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Volumen 7 (2022): Edición 1 (January 2022)

Volumen 6 (2021): Edición 1 (January 2021)

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Volumen 3 (2018): Edición 1 (December 2018)

Volumen 2 (2017): Edición 2 (December 2017)

Volumen 2 (2017): Edición 1 (June 2017)

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Volumen 1 (2016): Edición 1 (June 2016)

Detalles de la revista
Formato
Revista
eISSN
2543-4292
Publicado por primera vez
16 Apr 2016
Periodo de publicación
1 tiempo por año
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Volumen 6 (2021): Edición 1 (January 2021)

Detalles de la revista
Formato
Revista
eISSN
2543-4292
Publicado por primera vez
16 Apr 2016
Periodo de publicación
1 tiempo por año
Idiomas
Inglés

Buscar

21 Artículos
Acceso abierto

Control of a Four-wire Hybrid Prosumer Converter for Balancing Utility Grids

Publicado en línea: 08 Apr 2021
Páginas: 1 - 11

Resumen

Abstract

The paper presents the project of the power electronic AC/DC converter operating under a multiresonant control algorithm for prosumer applications. This design allows independent control of active and reactive power for any or each phase. Both the converter and its algorithm are based on a three-phase converter of four-wire topology (AC/DC 3p-4w) with a DC bus, which couple the converter to a renewable energy source and energy storage. Further, model and simulation tests were carried out in the Matlab-SIMULINK programming environment. The results obtained indicate that operation with deep unbalances and powers of opposite signs in individual phases results in current variations (oscillations) in the DC line, which is a significant limitation, and it can be concluded that the level of asymmetry should be limited to the level acceptable to the energy storage device.

Palabras clave

  • control of 4-wire converter
  • utility grid balancing
  • prosumer generation
  • hybrid PV converter
  • energy storage
Acceso abierto

MATLAB modelling of double sided photovoltaic cell module

Publicado en línea: 05 Jul 2021
Páginas: 12 - 25

Resumen

Abstract

In this paper, the equatorial coordinate system is taken as the celestial coordinates, the double-sided photovoltaic module irradiance model is established by using the MATLAB simulation software, and the double-sided photovoltaic module irradiance model is combined with the photovoltaic module model (Jianhui (2001)) to form the mathematical model of the real-time generation system of double-sided photovoltaic modules. The effectiveness of the simulation model was verified by building an experimental platform, and the output characteristics of the optimal line spacing between the double-sided p-v module and the single-sided p-v module were further tested and compared.

Palabras clave

  • double sided photovoltaic module
  • back irradiance
  • modelling
  • output characteristics
  • MPPT
Acceso abierto

A New 13-Level Switched-Capacitor Inverter with Reduced Device Count

Publicado en línea: 05 Jul 2021
Páginas: 26 - 41

Resumen

Abstract

This paper proposed a new voltage-boosting 13-level switched-capacitor (SC) cost-effective inverter. The proposed topology comprises fourteen transistors, three capacitors and a single DC source to produce a 13-level staircase waveform. The capacitor voltage balancing problem is inherently solved by the series/parallel technique. Structural description, working principle, calculation of optimum values of capacitance and modulation scheme are briefly described. The comparative analyses with the existing SC multilevel inverter (MLI) in terms of voltage gain, blocking voltage, total standing voltage (TSV), component per level factor and cost function illustrate the merits of the proposed topology. Further, simulation and experimental results at different loading conditions verify the feasibility of the proposed topology.

Palabras clave

  • multilevel inverter
  • switched capacitor
  • voltage gain
  • component per level factor
  • cost function
Acceso abierto

Application of Spectral and Wavelet Analysis of Stator Current to Detect Angular Misalignment in PMSM Drive Systems

Publicado en línea: 12 Jul 2021
Páginas: 42 - 60

Resumen

Abstract

This paper deals with the selected methods of detecting angular misalignment in drive systems with a permanent magnet synchronous motor (PMSM), which are based on the analysis of the stator phase current signal, as well as their experimental verification and comparison. The proposed and compared methods are spectral analysis and wavelet analysis of the stator current, stator current envelope, stator current space vector module. Furthermore, the influence of power supply frequency and load torque on the performance of the proposed diagnostic methods is also discussed. The experimental tests were carried out for an undamaged motor and for two levels of angular misalignment. The article discusses the question of exactly what damage symptoms can be extracted from each of the methods. In the case of spectral analyses, it is demonstrated which multiplicities of the failure frequency are the most sensitive to misalignment and the least sensitive to changes in motor operating condition, which may be considered novel in the case of drive systems with permanent magnet motors. It is also proven that discrete wavelet transform (DWT) of the envelope and monitoring of the value of the relevant components allows the detection of misalignment with the availability of measuring current only in one phase in various motor operating conditions.

Palabras clave

  • fault diagnosis
  • permanent magnet synchronous motor
  • angular misalignment
  • fast Fourier transform
  • discrete wavelet transform
Acceso abierto

Control Strategy of Parallel Systems with Efficiency Optimisation in Switched Reluctance Generators

Publicado en línea: 16 Jul 2021
Páginas: 61 - 74

Resumen

Abstract

To solve motor heating and life shortening of parallel switched reluctance generator (SRG) induced by uneven output currents due to different external characteristics, we generally adopt current sharing control (CSC) to make each parallel generator undertake large load currents on average to improve the reliability of parallel power generation system. However, the method usually causes additional loss of power because it does not consider the efficiency characteristics of each parallel generator. Therefore, with the efficiency expression for the parallel system of SRG established and analysed, the control strategy based on differential evolution (DE) algorithm is proposed as a mechanism by which to enhance generating capacity and reliability of multi-machine power generation from the perspective of efficiency optimisation. We re-adjust the reference current of each parallel generator to transform the working point of each generator and implement the efficiency optimisation of parallel system. The performance of the proposed control method is evaluated in detail by the simulation and experiment, and comparison with traditional CSC is carried out as well.

Palabras clave

  • switched reluctance generator
  • parallel system
  • efficiency optimization
  • differential evolution algorithm
Acceso abierto

Investigation on Control Strategies for a Single-Phase Photovoltaic Inverter Using PSCAD/EMTDC Software

Publicado en línea: 23 Jul 2021
Páginas: 75 - 99

Resumen

Abstract

In the last decades, electric power produced through photovoltaic conversion has been increasing because of the need to reduce fossil fuel burning. Recently, photovoltaic systems have become more competitive and their role in the renewable energies market share is steadily gaining in importance. Improvements in the power electronics employed in the DC/AC conversion are topics of interest in the quest for more efficient and eventually reduced-cost inverters. The goal of this paper is to perform an investigation of control strategies and propose a topology for a single-phase DC/AC converter for photovoltaic arrays using the simulation software Power System Computer Aided Design/ Electromagnetic Transient Design and Control (PSCAD/EMTDC). The circuit proposed in this paper employs an isolating transformer to a grid-connected photovoltaic inverter. The control strategy proposed uses the instantaneous reactive power theory (p–q theory) and phase-locked loop (PLL). The p-q theory uses two virtual axes in the Park Transformation, which provide to the control system a good dynamic response, accuracy, and decoupling between the control and power system. Computer simulations using the electromagnetic transient software PSCAD show the efficiency of the proposed strategy for a single-phase inverter. The control strategy and topology are quite simple and easy to implement in the future using a Digital Signal Processor (DSP). The results provide insights into new power electronics solutions, which can improve the efficiency and efficacy of the current available in DC/AC converters for photovoltaic systems.

Palabras clave

  • DC/DC converters
  • DC/AC converters
  • photovoltaic modules
  • pulse width modulation
  • solar energy
Acceso abierto

Effectiveness Analysis of Rolling Bearing Fault Detectors Based On Self-Organising Kohonen Neural Network – A Case Study of PMSM Drive

Publicado en línea: 23 Jul 2021
Páginas: 100 - 112

Resumen

Abstract

Due to their many advantages, permanent magnet synchronous motors (PMSMs) are increasingly used in not only industrial drive systems but also electric and hybrid vehicle drives, aviation and other applications. Unfortunately, PMSMs are not free from damage that occurs during their operation. It is assumed that about 40% of the damage that occurs is related to rolling bearing damage. This article focuses on the use of Kohonen neural network (KNN) for rolling bearing damage detection in a PMSM drive system. The symptoms from the fast Fourier transform (FFT) and Envelope (ENV) Analysis of the mechanical vibration acceleration signal were analysed. The signal ENV was obtained by applying the Hilbert transform (HT). Two neural network functions are discussed: a detector and a classifier. The detector detected the damage and the classifier determined the type of damage to the rolling bearing (undamaged bearing, damaged rolling element, outer or inner race). The effectiveness of the analysed networks from the point of view of the applied signal processing method, map size, type of neighbourhood radius, distance function and the influence of input data normalisation are presented. The results are presented in the form of a confusion matrix, together with 2D and 3D maps of active neurons.

Palabras clave

  • PMSM
  • rolling bearings
  • electric drive diagnostics
  • self-organising maps
  • shallow neural network
Acceso abierto

Robust Back-stepping Based Higher Order Sliding Mode Control of Non-Inverted Buck-Boost Converter for a Photovoltaic System

Publicado en línea: 01 Sep 2021
Páginas: 113 - 127

Resumen

Abstract

Photovoltaic (PV) system generates renewable energy from sunlight, which has low efficiency due to the variance in nature of temperature and irradiance in a fast changing environment condition. Different researchers have proposed different maximum power point tracking MPPT techniques to improve the efficiency. However, still there are many open issues. Thus, to address this, a non-linear back-stepping–based higher order sliding mode controller (BHOSMC) is proposed to harvest maximum power from PV system. The PV module and load is interfaced by a non-inverted buck-boost converter (NIBBC). A linear interpolation method is used for voltage generation and Lyapunov stability is used to verify the control system equation. MATLAB/Simulink software is used for testing the proposed controller performance. The experimental result verified that the proposed BHOSMC is robust, accurate and fast tracking, faultless and less chattering as compared to perturb and observe (P&O), back-stepping control (BSC) and back-stepping-based sliding mode control under rapidly varying meteorological condition.

Palabras clave

  • MPPT
  • buck-boost converter
  • non-linear control
  • back-stepping
  • higher order sliding
  • photovoltaic PV
Acceso abierto

Control and Operation of a Hybrid Actuator for Maglev Applications

Publicado en línea: 18 Oct 2021
Páginas: 129 - 144

Resumen

Abstract

The hybrid actuator presented in this article is meant to enable stationary and slow dynamic levitation in Maglev applications. The term ‘hybrid’ refers to the design of the actuator, which is a combination of permanent magnets (PM) and electromagnets. This paper presents an analytically computable control algorithm for the said hybrid actuator. The theory of magnetic circuits is summarized shortly and used to derive a cascaded control loop consisting of an inner current controller and an outer air gap controller. Since the uncontrolled hybrid actuator is inherently unstable, the system has to be stabilized. By introducing a PID-controller into the air gap control loop, the unstable behaviour of the uncontrolled system is changed into the system behaviour of a damped harmonic oscillator. The advantage of this approach is that the computed controller parameters of the PID-controller can easily be adjusted, so the system behaviour of damping and eigenfrequency can be selected within a certain range. For the execution of the control algorithm, a microcontroller (MCU) is used and for precise air gap measurement, an eddy current sensor is installed. Finally, the behaviour of the current- and air gap controller is discussed for different measurement results and the adjustable system behaviour of the damped harmonic oscillator is presented.

Palabras clave

  • Maglev
  • electromagnetic levitation
  • controlled permanent magnet
  • hybrid actuator
Acceso abierto

Sliding Mode Control of Hybrid Renewable Energy System Operating in Grid Connected and Stand-Alone Mode

Publicado en línea: 09 Oct 2021
Páginas: 144 - 166

Resumen

Abstract

This paper studies innovative application of sliding mode control (SMC) for a Hybrid Renewable Energy System (HRES) in grid-connected and autonomous modes of operation. The considered HRES includes a photovoltaic (PV), wind turbine (WT) based on a Permanent Magnet Synchronous Generator (PMSG). The PV generator is coupled to the common DC bus via a DC/DC converter. The latter is controlled by an MPPT algorithm based on the Adaptive Perturbation and Observation Algorithm Method (APOAM) to search the optimum working of this source. A SMC is utilized to manage the PV voltage to achieve the Maximum Power Point (MPP) by altering the obligation duty cycle. The battery interfaced by a bidirectional buck-boost DC/DC converter can be charged or discharged depending on the production situation. On the one hand, the wind turbine conversion chain is equipped with a PMSG and a rectifier controlled to regulate the operating point of the wind turbine to its optimum value. During a Stand-Alone Mode (SAM) operation, the Voltage Source Converter (VSC) was used for controlling the output voltage in terms of amplitude and frequency delivered to the AC load. However, in Grid-Connected Mode (GCM) operation, the VSC was adapted to control the electrical parameters of the grid. To better appreciate the advantages of the proposed SMC approach, we have proposed a series of comparative tests with the conventional PI control in the operating modes GC and SA and under different scenarios. The proposed control strategy has undeniable advantages in terms of control performance and very low total harmonic distortion THD value compared with the conventional PI control. Finally, It is concluded that the proposed approach improves the quality and provides a stable operation of the HRES.

Palabras clave

  • sliding mode control
  • grid-connected mode
  • stand-alone mode
  • hybrid renewable energy system
  • wind turbine
  • photovoltaic
  • battery energy storage system
  • maximum power point tracking
Acceso abierto

Laser Power Transmission and Its Application in Laser-Powered Electrical Motor Drive: A Review

Publicado en línea: 28 Nov 2021
Páginas: 167 - 184

Resumen

Abstract

Laser power transmission (LPT) is considered a potentially efficient way for power delivery, especially in long-distance wireless applications and harsh hazardous environmental conditions. In contrast to other wireless power transmission (WPT) methods, LPT has many advantages such as lower device size, focused transmitting direction and high power density. With the development of technology, LPT has been widely adopted in several fields. In conservative industries, the utilisation of LPT can resolve the limitation problem in a wired connection. The adverse influence of electromagnetic interference (EMI) concerning application and high-temperature fields can be reduced. This paper will give a simple review of LPT and demonstrate the basic concept of a photoelectric emitter, transmission channel and receiver material. Based on the recent research about diode laser beam combining technology and high-efficiency multi-junction photovoltaics (PV) materials, the advised LPT devices for simple application as laser power motor will be simply discussed.

Palabras clave

  • Laser power transmission
  • Photovoltaic materials
  • Laser diode
  • Optical fibre power transmission
  • Atmosphere transmission
Acceso abierto

Grid-Tied Neutral Point Clamped based Centralised Photovoltaic Inverter with Improved DC Link Voltage Balancing and Harmonic Minimisation Control

Publicado en línea: 15 Nov 2021
Páginas: 185 - 203

Resumen

Abstract

This paper proposes an improved space vector pulse width modulation (SVPWM) based DC link voltage balancing control of a three-phase three-level neutral point clamped (NPC) centralised inverter supplying the generated power from photo voltaic (PV) array to a three-phase utility grid. Two possible schemes have been developed based on the power conversion stage between PV array and the utility grid namely, two-stage (three-level boost converter three-phase three-level NPC inverter) and single-stage (three-phase three-level NPC inverter alone). The comparison between these two schemes has been thoroughly discussed in terms of the control strategies employed, power loss analysis and efficiency. The performance of the centralised inverter under different modes of operation has been investigated by developing the required control strategies for smooth operation. Using the proposed control strategy, the centralised inverter can be operated as a static synchronous compensator (STATCOM) during night time, if needed. The power loss incurred in the power-electronic converters has been analysed for constant and also for variable ambient temperature. The effectiveness of the centralised inverter as an active filter (AF) has also been verified when a three-phase non-linear load is considered in the system.

Palabras clave

  • photovoltaic multilevel inverters
  • neutral point voltage balancing
  • space vector pulse width modulation
  • current harmonic minimisation
Acceso abierto

Selected Nature-Inspired Algorithms in Function of PM Synchronous Motor Cogging Torque Minimisation

Publicado en línea: 15 Nov 2021
Páginas: 204 - 217

Resumen

Abstract

Both permanent magnet brushless DC motors and permanent magnet synchronous motors have attracted wide attention and are increasingly used in industrial high-performance applications in recent years. Those motors are known for their good electrical, magnetic and performance characteristics, but there is one parameter known as cogging torque that has a negative influence on the performance characteristics of the motor. This pulsating torque is generated as a result of the interaction between the stator teeth and the permanent magnets. The minimisation of the ripple of this torque in those permanent magnet motors is of great importance and is generally achieved by a special motor design which in the design process involves a variety of many geometrical motor parameters. In this research work, a novel approach will be introduced where two different nature-inspired algorithms, such as genetic algorithm (GA) and cuckoo search (CS) algorithm are used as an optimisation tool, in which the defined equation for the maximum value of the cogging torque is applied as an objective function. Therefore, a proper mathematical presentation of the maximum value of the cogging torque for the analysed synchronous motor is developed and implemented in the research work. For a detailed analysis of the three different motor models, the initial motor and the two optimised motor models are modelled and analysed using a finite element method approach. The cogging torque is analytically and numerically calculated and the results for all the models are presented.

Palabras clave

  • permanent magnet synchronous motor
  • optimisation methods
  • cogging torque
  • genetic algorithm
  • finite element method
Acceso abierto

Possibilities for Energy Saving Predictions in Elevators

Publicado en línea: 22 Dec 2021
Páginas: 218 - 228

Resumen

Abstract

Today, with the longing for smart and sustainable transportation, the elevator industry has undergone major metamorphism in the field of control algorithm, electric drive, and the motor. Amongst these, regenerative drive (RD) plays a pivotal role in making elevator technology more energy efficient. Rather than wasting the recovery energy from the machine as heat, RD recovers it as green energy. Conventional direct current (DC) motors ruled the elevator industry for many years and were adopted as standard type of elevator motors. But with the advancement in electric drive technology, alternating current (AC) motors, especially induction motors, flourished in the later part. Recently with the introduction of Permanent Magnet Synchronous Motors (PMSM) technology, the elevator revolution began in terms of power quality, ride quality, and green energy. Likewise, contrasted with different types of vertical transportation machines, PMSMs have better powerful execution, compact size, and higher system-level efficiency. Recently, with the rapid improvement in intensity hardware, utilization of rare earth magnetic materials, and indubitably advanced research, PMSM has rapidly changed systems globally. PMSM is a multivariable, nonlinear, and high-coupling framework. The torque and stator current present a unique capacity connection. Attractive fields can be decoupled to gain decent power outcomes. With the presentation of regenerative PMSM, electrical drives coupled to system integrated frameworks for recovery energy has enhanced savings in power consumptions.

Palabras clave

  • energy management
  • drives
  • elevators
  • PMSM
Acceso abierto

Enhanced Reliability for Winding Machine via New Fault Tolerant Control Based on RST-Backstepping Controller

Publicado en línea: 28 Nov 2021
Páginas: 229 - 241

Resumen

Abstract

Due to the external disturbances, model uncertainties, strong coupling, and occurred faults, the winding machine presents a great control challenge. In order to deal with these problems, this paper presents the formulation of a novel scheme of fault tolerant control (FTC) for three-motor web-winding systems; it is concerned with the nonlinear robust backstepping control based on the combination of RST and backstepping controllers where the process is modelled by a nonlinear model. The main contribution of the paper is that the approach developed here summarises the performance of RST and backstepping controllers in order to design a robust controller capable of eliminating external disturbances and sensor faults affecting the system. The stability of the whole system is proven using the Lyapunov theory. Finally, analysis in comparison with the conventional backstepping controller and simulations in the MATLAB environment are accomplished to confirm the efficiency of the proposed method.

Palabras clave

  • winding machine
  • fault tolerant control
  • backstepping control
  • RST control
Acceso abierto

An Adaptive Control Strategy for a Low-Ripple Boost Converter in BLDC Motor Speed Control

Publicado en línea: 13 Dec 2021
Páginas: 242 - 259

Resumen

Abstract

Conventional boost converters are widely used for connecting low-voltage power sources and inverters in motor control. However, a large filter capacitor bank is often used to reduce DC-link ripples that occur when an inverter is connected to a boost converter. Otherwise, significant voltage and current perturbations can impact on battery performance degradation and cause torque ripple, speed ripple and vibration in brushless DC (BLDC) motors. To suppress the converter’s DC-link ripple, this paper proposes a new control strategy for boost converter controller to generate low-ripple DC-link voltage or current at different motor speeds. In the proposed method, observers are designed to adaptively estimate the DC-link voltage and current harmonics. The harmonic terms are used as feedback signals to calculate the DC converter’s duty cycle. The entire control model is implemented on an embedded system, and its robustness is verified by simulation and experimental results that show the DC-link voltage and current ripples can be reduced by about 50% and 30%, respectively.

Palabras clave

  • boost converter
  • BLDC
  • harmonics
  • observer
  • feedback control
Acceso abierto

A Bidirectional Buck-Boost Converter-Based Switching Ripple Communication Strategy for Intelligent Street Lighting Systems

Publicado en línea: 22 Dec 2021
Páginas: 260 - 275

Resumen

Abstract

The light-emitting diode (LED) is an essential component of intelligent street lighting (ISL) systems. An efficient ISL system can not only reduce power consumption by planning LED illuminating time but also reduce maintenance costs through a high degree of automation. In this paper, a buck-boost converter is used to realise composite transmission of power and signals for an ISL system. The power is modulated by the pulse width modulation (PWM) approach, and the switching ripple generated in the PWM process is utilised as the carrier of the signals transmitted between the remote-control centre and the slave nodes. Moreover, the proposed model involves a ‘request to send (RTS)/confirm to send (CTS)’ mechanism to avoid signal conflicts. Compared with the conventional power line communication (PLC) approach, the proposed transmission scheme has the advantages of simple circuit structure and simple system wiring. Additionally, a simulation model built in MATLAB/Simulink proves the designed transmission method has strong anti-noise ability.

Palabras clave

  • bidirectional switching ripple communication
  • buck-boost converter
  • intelligent street lighting system
  • pulse width modulation
  • smart city
Acceso abierto

Artificial Neural Network-Based Gain-Scheduled State Feedback Speed Controller for Synchronous Reluctance Motor

Publicado en línea: 17 Dec 2021
Páginas: 276 - 288

Resumen

Abstract

This paper focuses on designing a gain-scheduled (G-S) state feedback controller (SFC) for synchronous reluctance motor (SynRM) speed control with non-linear inductance characteristics. The augmented model of the drive with additional state variables is introduced to assure precise control of selected state variables (i.e. angular speed and d-axis current). Optimal, non-constant coefficients of the controller are calculated using a linear-quadratic optimisation method. Non-constant coefficients are approximated using an artificial neural network (ANN) to assure superior accuracy and relatively low usage of resources during implementation. To the best of our knowledge, this is the first time when ANN-based gain-scheduled state feedback controller (G-S SFC) is applied for speed control of SynRM. Based on numerous simulation tests, including a comparison with a signum-based SFC, it is shown that the proposed solution assures good dynamical behaviour of SynRM drive and robustness against q-axis inductance, the moment of inertia and viscous friction fluctuations.

Palabras clave

  • synchronous reluctance motor
  • state feedback controller
  • gain-scheduling
  • artificial neural network
  • robustness analysis
Acceso abierto

The Effect of Different Decision-Making Methods on Multi-Objective Optimisation of Predictive Torque Control Strategy

Publicado en línea: 17 Dec 2021
Páginas: 289 - 300

Resumen

Abstract

Today, a clear trend in electrification process has emerged in all areas to cope with carbon emissions. For this purpose, the widespread use of electric cars and wind energy conversion systems has increased the attention and importance of electric machines. To overcome limitations in mature control techniques, model predictive control (MPC) strategies have been proposed. Of these strategies, predictive torque control (PTC) has been well accepted in the control of electric machines. However, it suffers from the selection of weighting factors in the cost function. In this paper, the weighting factor associated with the flux error term is optimised by the non-dominated sorting genetic algorithm (NSGA-II) algorithm through torque and flux errors. The NSGA-II algorithm generates a set of optimal solutions called Pareto front solutions, and a possible solution must be selected from among the Pareto front solutions for use in the PTC strategy. Unlike the current literature, three decision-making methods are applied to the Pareto front solutions and the weighting factors selected by each method are tested under different operating conditions in terms of torque ripples, flux ripples, cur-rent harmonics and average switching frequencies. Finally, a decision-making method is recommended.

Palabras clave

  • predictive torque control
  • induction motor
  • multi-objective optimisation
  • decision-making method
Acceso abierto

Initial Rotor Position Detection of Induction Machines Using Feedforward Sensorless Saliency Separation

Publicado en línea: 23 Dec 2021
Páginas: 301 - 313

Resumen

Abstract

The use of induction machine spatial saliencies for sensorless vector control in the proximity of zero electrical frequency has been extensively researched over the last few decades. A robust technique to extract machine saliencies is called voltage step excitation, and it computes a saliency phasor out of phase current derivatives resulting from specific voltage steps generated by the inverter switching. Within the saliency phasor, all machine saliencies appear superposed. For some machine constructions, multiple saliencies are present, containing information about the spatial, magnetic and geometric state of the machine. Due to its direct relation with the rotor angle and its high accuracy, rotor slotting saliency is often chosen as the sensorless control signal. In order to exclusively access rotor slotting, saliency separation needs to be carried out, with the goal of eliminating all non-control saliencies from the saliency phasor. In this research, feedforward harmonic compensation based on look-up tables (LUTs) is chosen. The idea is to estimate each saliency in relation to amplitude and phase shift once, store such information in a torque-dependent LUT and use it for feedforward compensation. Yet, several saliencies are linked to the rotor position and, thus, the stored phase shift in the LUT is fixed to a defined rotor position at which the saliency estimation was performed. For the feedforward compensation to work during each sensorless start-up, an initial rotor slot detection must be carried out. This paper presents a technique to estimate initial rotor angle based only on the inherent characteristics of the induction machine multi-saliencies and an iterative feedforward compensation process that requires no extra resources and only a few PWM (Pulse Width Modulation) periods to achieve initial slot rotor angle. Experimental results measured at two different test benches prove the high accuracy of the method.

Palabras clave

  • Induction machines
  • harmonic compensation
  • rotor slotting saliency
  • sensorless control
Acceso abierto

Active Damping in Series Connected Power Modules with Continuous Output Voltage

Publicado en línea: 30 Dec 2021
Páginas: 314 - 335

Resumen

Abstract

This paper presents a modular and scalable power electronics concept for motor control with continuous output voltage. In contrast to multilevel concepts, modules with continuous output voltage are connected in series. The continuous output voltage of each module is obtained by using gallium nitride (GaN) high electron motility transistor (HEMT)s as switches inside the modules with a switching frequency in the range between 500 kHz and 1 MHz. Due to this high switching frequency a LC filter is integrated into the module resulting in a continuous output voltage. A main topic of the paper is the active damping of this LC output filter for each module and the analysis of the series connection of the damping behaviour. The results are illustrated with simulations and measurements.

Palabras clave

  • power electronics
  • modularity
  • scalability
  • GaN
  • active filter damping
21 Artículos
Acceso abierto

Control of a Four-wire Hybrid Prosumer Converter for Balancing Utility Grids

Publicado en línea: 08 Apr 2021
Páginas: 1 - 11

Resumen

Abstract

The paper presents the project of the power electronic AC/DC converter operating under a multiresonant control algorithm for prosumer applications. This design allows independent control of active and reactive power for any or each phase. Both the converter and its algorithm are based on a three-phase converter of four-wire topology (AC/DC 3p-4w) with a DC bus, which couple the converter to a renewable energy source and energy storage. Further, model and simulation tests were carried out in the Matlab-SIMULINK programming environment. The results obtained indicate that operation with deep unbalances and powers of opposite signs in individual phases results in current variations (oscillations) in the DC line, which is a significant limitation, and it can be concluded that the level of asymmetry should be limited to the level acceptable to the energy storage device.

Palabras clave

  • control of 4-wire converter
  • utility grid balancing
  • prosumer generation
  • hybrid PV converter
  • energy storage
Acceso abierto

MATLAB modelling of double sided photovoltaic cell module

Publicado en línea: 05 Jul 2021
Páginas: 12 - 25

Resumen

Abstract

In this paper, the equatorial coordinate system is taken as the celestial coordinates, the double-sided photovoltaic module irradiance model is established by using the MATLAB simulation software, and the double-sided photovoltaic module irradiance model is combined with the photovoltaic module model (Jianhui (2001)) to form the mathematical model of the real-time generation system of double-sided photovoltaic modules. The effectiveness of the simulation model was verified by building an experimental platform, and the output characteristics of the optimal line spacing between the double-sided p-v module and the single-sided p-v module were further tested and compared.

Palabras clave

  • double sided photovoltaic module
  • back irradiance
  • modelling
  • output characteristics
  • MPPT
Acceso abierto

A New 13-Level Switched-Capacitor Inverter with Reduced Device Count

Publicado en línea: 05 Jul 2021
Páginas: 26 - 41

Resumen

Abstract

This paper proposed a new voltage-boosting 13-level switched-capacitor (SC) cost-effective inverter. The proposed topology comprises fourteen transistors, three capacitors and a single DC source to produce a 13-level staircase waveform. The capacitor voltage balancing problem is inherently solved by the series/parallel technique. Structural description, working principle, calculation of optimum values of capacitance and modulation scheme are briefly described. The comparative analyses with the existing SC multilevel inverter (MLI) in terms of voltage gain, blocking voltage, total standing voltage (TSV), component per level factor and cost function illustrate the merits of the proposed topology. Further, simulation and experimental results at different loading conditions verify the feasibility of the proposed topology.

Palabras clave

  • multilevel inverter
  • switched capacitor
  • voltage gain
  • component per level factor
  • cost function
Acceso abierto

Application of Spectral and Wavelet Analysis of Stator Current to Detect Angular Misalignment in PMSM Drive Systems

Publicado en línea: 12 Jul 2021
Páginas: 42 - 60

Resumen

Abstract

This paper deals with the selected methods of detecting angular misalignment in drive systems with a permanent magnet synchronous motor (PMSM), which are based on the analysis of the stator phase current signal, as well as their experimental verification and comparison. The proposed and compared methods are spectral analysis and wavelet analysis of the stator current, stator current envelope, stator current space vector module. Furthermore, the influence of power supply frequency and load torque on the performance of the proposed diagnostic methods is also discussed. The experimental tests were carried out for an undamaged motor and for two levels of angular misalignment. The article discusses the question of exactly what damage symptoms can be extracted from each of the methods. In the case of spectral analyses, it is demonstrated which multiplicities of the failure frequency are the most sensitive to misalignment and the least sensitive to changes in motor operating condition, which may be considered novel in the case of drive systems with permanent magnet motors. It is also proven that discrete wavelet transform (DWT) of the envelope and monitoring of the value of the relevant components allows the detection of misalignment with the availability of measuring current only in one phase in various motor operating conditions.

Palabras clave

  • fault diagnosis
  • permanent magnet synchronous motor
  • angular misalignment
  • fast Fourier transform
  • discrete wavelet transform
Acceso abierto

Control Strategy of Parallel Systems with Efficiency Optimisation in Switched Reluctance Generators

Publicado en línea: 16 Jul 2021
Páginas: 61 - 74

Resumen

Abstract

To solve motor heating and life shortening of parallel switched reluctance generator (SRG) induced by uneven output currents due to different external characteristics, we generally adopt current sharing control (CSC) to make each parallel generator undertake large load currents on average to improve the reliability of parallel power generation system. However, the method usually causes additional loss of power because it does not consider the efficiency characteristics of each parallel generator. Therefore, with the efficiency expression for the parallel system of SRG established and analysed, the control strategy based on differential evolution (DE) algorithm is proposed as a mechanism by which to enhance generating capacity and reliability of multi-machine power generation from the perspective of efficiency optimisation. We re-adjust the reference current of each parallel generator to transform the working point of each generator and implement the efficiency optimisation of parallel system. The performance of the proposed control method is evaluated in detail by the simulation and experiment, and comparison with traditional CSC is carried out as well.

Palabras clave

  • switched reluctance generator
  • parallel system
  • efficiency optimization
  • differential evolution algorithm
Acceso abierto

Investigation on Control Strategies for a Single-Phase Photovoltaic Inverter Using PSCAD/EMTDC Software

Publicado en línea: 23 Jul 2021
Páginas: 75 - 99

Resumen

Abstract

In the last decades, electric power produced through photovoltaic conversion has been increasing because of the need to reduce fossil fuel burning. Recently, photovoltaic systems have become more competitive and their role in the renewable energies market share is steadily gaining in importance. Improvements in the power electronics employed in the DC/AC conversion are topics of interest in the quest for more efficient and eventually reduced-cost inverters. The goal of this paper is to perform an investigation of control strategies and propose a topology for a single-phase DC/AC converter for photovoltaic arrays using the simulation software Power System Computer Aided Design/ Electromagnetic Transient Design and Control (PSCAD/EMTDC). The circuit proposed in this paper employs an isolating transformer to a grid-connected photovoltaic inverter. The control strategy proposed uses the instantaneous reactive power theory (p–q theory) and phase-locked loop (PLL). The p-q theory uses two virtual axes in the Park Transformation, which provide to the control system a good dynamic response, accuracy, and decoupling between the control and power system. Computer simulations using the electromagnetic transient software PSCAD show the efficiency of the proposed strategy for a single-phase inverter. The control strategy and topology are quite simple and easy to implement in the future using a Digital Signal Processor (DSP). The results provide insights into new power electronics solutions, which can improve the efficiency and efficacy of the current available in DC/AC converters for photovoltaic systems.

Palabras clave

  • DC/DC converters
  • DC/AC converters
  • photovoltaic modules
  • pulse width modulation
  • solar energy
Acceso abierto

Effectiveness Analysis of Rolling Bearing Fault Detectors Based On Self-Organising Kohonen Neural Network – A Case Study of PMSM Drive

Publicado en línea: 23 Jul 2021
Páginas: 100 - 112

Resumen

Abstract

Due to their many advantages, permanent magnet synchronous motors (PMSMs) are increasingly used in not only industrial drive systems but also electric and hybrid vehicle drives, aviation and other applications. Unfortunately, PMSMs are not free from damage that occurs during their operation. It is assumed that about 40% of the damage that occurs is related to rolling bearing damage. This article focuses on the use of Kohonen neural network (KNN) for rolling bearing damage detection in a PMSM drive system. The symptoms from the fast Fourier transform (FFT) and Envelope (ENV) Analysis of the mechanical vibration acceleration signal were analysed. The signal ENV was obtained by applying the Hilbert transform (HT). Two neural network functions are discussed: a detector and a classifier. The detector detected the damage and the classifier determined the type of damage to the rolling bearing (undamaged bearing, damaged rolling element, outer or inner race). The effectiveness of the analysed networks from the point of view of the applied signal processing method, map size, type of neighbourhood radius, distance function and the influence of input data normalisation are presented. The results are presented in the form of a confusion matrix, together with 2D and 3D maps of active neurons.

Palabras clave

  • PMSM
  • rolling bearings
  • electric drive diagnostics
  • self-organising maps
  • shallow neural network
Acceso abierto

Robust Back-stepping Based Higher Order Sliding Mode Control of Non-Inverted Buck-Boost Converter for a Photovoltaic System

Publicado en línea: 01 Sep 2021
Páginas: 113 - 127

Resumen

Abstract

Photovoltaic (PV) system generates renewable energy from sunlight, which has low efficiency due to the variance in nature of temperature and irradiance in a fast changing environment condition. Different researchers have proposed different maximum power point tracking MPPT techniques to improve the efficiency. However, still there are many open issues. Thus, to address this, a non-linear back-stepping–based higher order sliding mode controller (BHOSMC) is proposed to harvest maximum power from PV system. The PV module and load is interfaced by a non-inverted buck-boost converter (NIBBC). A linear interpolation method is used for voltage generation and Lyapunov stability is used to verify the control system equation. MATLAB/Simulink software is used for testing the proposed controller performance. The experimental result verified that the proposed BHOSMC is robust, accurate and fast tracking, faultless and less chattering as compared to perturb and observe (P&O), back-stepping control (BSC) and back-stepping-based sliding mode control under rapidly varying meteorological condition.

Palabras clave

  • MPPT
  • buck-boost converter
  • non-linear control
  • back-stepping
  • higher order sliding
  • photovoltaic PV
Acceso abierto

Control and Operation of a Hybrid Actuator for Maglev Applications

Publicado en línea: 18 Oct 2021
Páginas: 129 - 144

Resumen

Abstract

The hybrid actuator presented in this article is meant to enable stationary and slow dynamic levitation in Maglev applications. The term ‘hybrid’ refers to the design of the actuator, which is a combination of permanent magnets (PM) and electromagnets. This paper presents an analytically computable control algorithm for the said hybrid actuator. The theory of magnetic circuits is summarized shortly and used to derive a cascaded control loop consisting of an inner current controller and an outer air gap controller. Since the uncontrolled hybrid actuator is inherently unstable, the system has to be stabilized. By introducing a PID-controller into the air gap control loop, the unstable behaviour of the uncontrolled system is changed into the system behaviour of a damped harmonic oscillator. The advantage of this approach is that the computed controller parameters of the PID-controller can easily be adjusted, so the system behaviour of damping and eigenfrequency can be selected within a certain range. For the execution of the control algorithm, a microcontroller (MCU) is used and for precise air gap measurement, an eddy current sensor is installed. Finally, the behaviour of the current- and air gap controller is discussed for different measurement results and the adjustable system behaviour of the damped harmonic oscillator is presented.

Palabras clave

  • Maglev
  • electromagnetic levitation
  • controlled permanent magnet
  • hybrid actuator
Acceso abierto

Sliding Mode Control of Hybrid Renewable Energy System Operating in Grid Connected and Stand-Alone Mode

Publicado en línea: 09 Oct 2021
Páginas: 144 - 166

Resumen

Abstract

This paper studies innovative application of sliding mode control (SMC) for a Hybrid Renewable Energy System (HRES) in grid-connected and autonomous modes of operation. The considered HRES includes a photovoltaic (PV), wind turbine (WT) based on a Permanent Magnet Synchronous Generator (PMSG). The PV generator is coupled to the common DC bus via a DC/DC converter. The latter is controlled by an MPPT algorithm based on the Adaptive Perturbation and Observation Algorithm Method (APOAM) to search the optimum working of this source. A SMC is utilized to manage the PV voltage to achieve the Maximum Power Point (MPP) by altering the obligation duty cycle. The battery interfaced by a bidirectional buck-boost DC/DC converter can be charged or discharged depending on the production situation. On the one hand, the wind turbine conversion chain is equipped with a PMSG and a rectifier controlled to regulate the operating point of the wind turbine to its optimum value. During a Stand-Alone Mode (SAM) operation, the Voltage Source Converter (VSC) was used for controlling the output voltage in terms of amplitude and frequency delivered to the AC load. However, in Grid-Connected Mode (GCM) operation, the VSC was adapted to control the electrical parameters of the grid. To better appreciate the advantages of the proposed SMC approach, we have proposed a series of comparative tests with the conventional PI control in the operating modes GC and SA and under different scenarios. The proposed control strategy has undeniable advantages in terms of control performance and very low total harmonic distortion THD value compared with the conventional PI control. Finally, It is concluded that the proposed approach improves the quality and provides a stable operation of the HRES.

Palabras clave

  • sliding mode control
  • grid-connected mode
  • stand-alone mode
  • hybrid renewable energy system
  • wind turbine
  • photovoltaic
  • battery energy storage system
  • maximum power point tracking
Acceso abierto

Laser Power Transmission and Its Application in Laser-Powered Electrical Motor Drive: A Review

Publicado en línea: 28 Nov 2021
Páginas: 167 - 184

Resumen

Abstract

Laser power transmission (LPT) is considered a potentially efficient way for power delivery, especially in long-distance wireless applications and harsh hazardous environmental conditions. In contrast to other wireless power transmission (WPT) methods, LPT has many advantages such as lower device size, focused transmitting direction and high power density. With the development of technology, LPT has been widely adopted in several fields. In conservative industries, the utilisation of LPT can resolve the limitation problem in a wired connection. The adverse influence of electromagnetic interference (EMI) concerning application and high-temperature fields can be reduced. This paper will give a simple review of LPT and demonstrate the basic concept of a photoelectric emitter, transmission channel and receiver material. Based on the recent research about diode laser beam combining technology and high-efficiency multi-junction photovoltaics (PV) materials, the advised LPT devices for simple application as laser power motor will be simply discussed.

Palabras clave

  • Laser power transmission
  • Photovoltaic materials
  • Laser diode
  • Optical fibre power transmission
  • Atmosphere transmission
Acceso abierto

Grid-Tied Neutral Point Clamped based Centralised Photovoltaic Inverter with Improved DC Link Voltage Balancing and Harmonic Minimisation Control

Publicado en línea: 15 Nov 2021
Páginas: 185 - 203

Resumen

Abstract

This paper proposes an improved space vector pulse width modulation (SVPWM) based DC link voltage balancing control of a three-phase three-level neutral point clamped (NPC) centralised inverter supplying the generated power from photo voltaic (PV) array to a three-phase utility grid. Two possible schemes have been developed based on the power conversion stage between PV array and the utility grid namely, two-stage (three-level boost converter three-phase three-level NPC inverter) and single-stage (three-phase three-level NPC inverter alone). The comparison between these two schemes has been thoroughly discussed in terms of the control strategies employed, power loss analysis and efficiency. The performance of the centralised inverter under different modes of operation has been investigated by developing the required control strategies for smooth operation. Using the proposed control strategy, the centralised inverter can be operated as a static synchronous compensator (STATCOM) during night time, if needed. The power loss incurred in the power-electronic converters has been analysed for constant and also for variable ambient temperature. The effectiveness of the centralised inverter as an active filter (AF) has also been verified when a three-phase non-linear load is considered in the system.

Palabras clave

  • photovoltaic multilevel inverters
  • neutral point voltage balancing
  • space vector pulse width modulation
  • current harmonic minimisation
Acceso abierto

Selected Nature-Inspired Algorithms in Function of PM Synchronous Motor Cogging Torque Minimisation

Publicado en línea: 15 Nov 2021
Páginas: 204 - 217

Resumen

Abstract

Both permanent magnet brushless DC motors and permanent magnet synchronous motors have attracted wide attention and are increasingly used in industrial high-performance applications in recent years. Those motors are known for their good electrical, magnetic and performance characteristics, but there is one parameter known as cogging torque that has a negative influence on the performance characteristics of the motor. This pulsating torque is generated as a result of the interaction between the stator teeth and the permanent magnets. The minimisation of the ripple of this torque in those permanent magnet motors is of great importance and is generally achieved by a special motor design which in the design process involves a variety of many geometrical motor parameters. In this research work, a novel approach will be introduced where two different nature-inspired algorithms, such as genetic algorithm (GA) and cuckoo search (CS) algorithm are used as an optimisation tool, in which the defined equation for the maximum value of the cogging torque is applied as an objective function. Therefore, a proper mathematical presentation of the maximum value of the cogging torque for the analysed synchronous motor is developed and implemented in the research work. For a detailed analysis of the three different motor models, the initial motor and the two optimised motor models are modelled and analysed using a finite element method approach. The cogging torque is analytically and numerically calculated and the results for all the models are presented.

Palabras clave

  • permanent magnet synchronous motor
  • optimisation methods
  • cogging torque
  • genetic algorithm
  • finite element method
Acceso abierto

Possibilities for Energy Saving Predictions in Elevators

Publicado en línea: 22 Dec 2021
Páginas: 218 - 228

Resumen

Abstract

Today, with the longing for smart and sustainable transportation, the elevator industry has undergone major metamorphism in the field of control algorithm, electric drive, and the motor. Amongst these, regenerative drive (RD) plays a pivotal role in making elevator technology more energy efficient. Rather than wasting the recovery energy from the machine as heat, RD recovers it as green energy. Conventional direct current (DC) motors ruled the elevator industry for many years and were adopted as standard type of elevator motors. But with the advancement in electric drive technology, alternating current (AC) motors, especially induction motors, flourished in the later part. Recently with the introduction of Permanent Magnet Synchronous Motors (PMSM) technology, the elevator revolution began in terms of power quality, ride quality, and green energy. Likewise, contrasted with different types of vertical transportation machines, PMSMs have better powerful execution, compact size, and higher system-level efficiency. Recently, with the rapid improvement in intensity hardware, utilization of rare earth magnetic materials, and indubitably advanced research, PMSM has rapidly changed systems globally. PMSM is a multivariable, nonlinear, and high-coupling framework. The torque and stator current present a unique capacity connection. Attractive fields can be decoupled to gain decent power outcomes. With the presentation of regenerative PMSM, electrical drives coupled to system integrated frameworks for recovery energy has enhanced savings in power consumptions.

Palabras clave

  • energy management
  • drives
  • elevators
  • PMSM
Acceso abierto

Enhanced Reliability for Winding Machine via New Fault Tolerant Control Based on RST-Backstepping Controller

Publicado en línea: 28 Nov 2021
Páginas: 229 - 241

Resumen

Abstract

Due to the external disturbances, model uncertainties, strong coupling, and occurred faults, the winding machine presents a great control challenge. In order to deal with these problems, this paper presents the formulation of a novel scheme of fault tolerant control (FTC) for three-motor web-winding systems; it is concerned with the nonlinear robust backstepping control based on the combination of RST and backstepping controllers where the process is modelled by a nonlinear model. The main contribution of the paper is that the approach developed here summarises the performance of RST and backstepping controllers in order to design a robust controller capable of eliminating external disturbances and sensor faults affecting the system. The stability of the whole system is proven using the Lyapunov theory. Finally, analysis in comparison with the conventional backstepping controller and simulations in the MATLAB environment are accomplished to confirm the efficiency of the proposed method.

Palabras clave

  • winding machine
  • fault tolerant control
  • backstepping control
  • RST control
Acceso abierto

An Adaptive Control Strategy for a Low-Ripple Boost Converter in BLDC Motor Speed Control

Publicado en línea: 13 Dec 2021
Páginas: 242 - 259

Resumen

Abstract

Conventional boost converters are widely used for connecting low-voltage power sources and inverters in motor control. However, a large filter capacitor bank is often used to reduce DC-link ripples that occur when an inverter is connected to a boost converter. Otherwise, significant voltage and current perturbations can impact on battery performance degradation and cause torque ripple, speed ripple and vibration in brushless DC (BLDC) motors. To suppress the converter’s DC-link ripple, this paper proposes a new control strategy for boost converter controller to generate low-ripple DC-link voltage or current at different motor speeds. In the proposed method, observers are designed to adaptively estimate the DC-link voltage and current harmonics. The harmonic terms are used as feedback signals to calculate the DC converter’s duty cycle. The entire control model is implemented on an embedded system, and its robustness is verified by simulation and experimental results that show the DC-link voltage and current ripples can be reduced by about 50% and 30%, respectively.

Palabras clave

  • boost converter
  • BLDC
  • harmonics
  • observer
  • feedback control
Acceso abierto

A Bidirectional Buck-Boost Converter-Based Switching Ripple Communication Strategy for Intelligent Street Lighting Systems

Publicado en línea: 22 Dec 2021
Páginas: 260 - 275

Resumen

Abstract

The light-emitting diode (LED) is an essential component of intelligent street lighting (ISL) systems. An efficient ISL system can not only reduce power consumption by planning LED illuminating time but also reduce maintenance costs through a high degree of automation. In this paper, a buck-boost converter is used to realise composite transmission of power and signals for an ISL system. The power is modulated by the pulse width modulation (PWM) approach, and the switching ripple generated in the PWM process is utilised as the carrier of the signals transmitted between the remote-control centre and the slave nodes. Moreover, the proposed model involves a ‘request to send (RTS)/confirm to send (CTS)’ mechanism to avoid signal conflicts. Compared with the conventional power line communication (PLC) approach, the proposed transmission scheme has the advantages of simple circuit structure and simple system wiring. Additionally, a simulation model built in MATLAB/Simulink proves the designed transmission method has strong anti-noise ability.

Palabras clave

  • bidirectional switching ripple communication
  • buck-boost converter
  • intelligent street lighting system
  • pulse width modulation
  • smart city
Acceso abierto

Artificial Neural Network-Based Gain-Scheduled State Feedback Speed Controller for Synchronous Reluctance Motor

Publicado en línea: 17 Dec 2021
Páginas: 276 - 288

Resumen

Abstract

This paper focuses on designing a gain-scheduled (G-S) state feedback controller (SFC) for synchronous reluctance motor (SynRM) speed control with non-linear inductance characteristics. The augmented model of the drive with additional state variables is introduced to assure precise control of selected state variables (i.e. angular speed and d-axis current). Optimal, non-constant coefficients of the controller are calculated using a linear-quadratic optimisation method. Non-constant coefficients are approximated using an artificial neural network (ANN) to assure superior accuracy and relatively low usage of resources during implementation. To the best of our knowledge, this is the first time when ANN-based gain-scheduled state feedback controller (G-S SFC) is applied for speed control of SynRM. Based on numerous simulation tests, including a comparison with a signum-based SFC, it is shown that the proposed solution assures good dynamical behaviour of SynRM drive and robustness against q-axis inductance, the moment of inertia and viscous friction fluctuations.

Palabras clave

  • synchronous reluctance motor
  • state feedback controller
  • gain-scheduling
  • artificial neural network
  • robustness analysis
Acceso abierto

The Effect of Different Decision-Making Methods on Multi-Objective Optimisation of Predictive Torque Control Strategy

Publicado en línea: 17 Dec 2021
Páginas: 289 - 300

Resumen

Abstract

Today, a clear trend in electrification process has emerged in all areas to cope with carbon emissions. For this purpose, the widespread use of electric cars and wind energy conversion systems has increased the attention and importance of electric machines. To overcome limitations in mature control techniques, model predictive control (MPC) strategies have been proposed. Of these strategies, predictive torque control (PTC) has been well accepted in the control of electric machines. However, it suffers from the selection of weighting factors in the cost function. In this paper, the weighting factor associated with the flux error term is optimised by the non-dominated sorting genetic algorithm (NSGA-II) algorithm through torque and flux errors. The NSGA-II algorithm generates a set of optimal solutions called Pareto front solutions, and a possible solution must be selected from among the Pareto front solutions for use in the PTC strategy. Unlike the current literature, three decision-making methods are applied to the Pareto front solutions and the weighting factors selected by each method are tested under different operating conditions in terms of torque ripples, flux ripples, cur-rent harmonics and average switching frequencies. Finally, a decision-making method is recommended.

Palabras clave

  • predictive torque control
  • induction motor
  • multi-objective optimisation
  • decision-making method
Acceso abierto

Initial Rotor Position Detection of Induction Machines Using Feedforward Sensorless Saliency Separation

Publicado en línea: 23 Dec 2021
Páginas: 301 - 313

Resumen

Abstract

The use of induction machine spatial saliencies for sensorless vector control in the proximity of zero electrical frequency has been extensively researched over the last few decades. A robust technique to extract machine saliencies is called voltage step excitation, and it computes a saliency phasor out of phase current derivatives resulting from specific voltage steps generated by the inverter switching. Within the saliency phasor, all machine saliencies appear superposed. For some machine constructions, multiple saliencies are present, containing information about the spatial, magnetic and geometric state of the machine. Due to its direct relation with the rotor angle and its high accuracy, rotor slotting saliency is often chosen as the sensorless control signal. In order to exclusively access rotor slotting, saliency separation needs to be carried out, with the goal of eliminating all non-control saliencies from the saliency phasor. In this research, feedforward harmonic compensation based on look-up tables (LUTs) is chosen. The idea is to estimate each saliency in relation to amplitude and phase shift once, store such information in a torque-dependent LUT and use it for feedforward compensation. Yet, several saliencies are linked to the rotor position and, thus, the stored phase shift in the LUT is fixed to a defined rotor position at which the saliency estimation was performed. For the feedforward compensation to work during each sensorless start-up, an initial rotor slot detection must be carried out. This paper presents a technique to estimate initial rotor angle based only on the inherent characteristics of the induction machine multi-saliencies and an iterative feedforward compensation process that requires no extra resources and only a few PWM (Pulse Width Modulation) periods to achieve initial slot rotor angle. Experimental results measured at two different test benches prove the high accuracy of the method.

Palabras clave

  • Induction machines
  • harmonic compensation
  • rotor slotting saliency
  • sensorless control
Acceso abierto

Active Damping in Series Connected Power Modules with Continuous Output Voltage

Publicado en línea: 30 Dec 2021
Páginas: 314 - 335

Resumen

Abstract

This paper presents a modular and scalable power electronics concept for motor control with continuous output voltage. In contrast to multilevel concepts, modules with continuous output voltage are connected in series. The continuous output voltage of each module is obtained by using gallium nitride (GaN) high electron motility transistor (HEMT)s as switches inside the modules with a switching frequency in the range between 500 kHz and 1 MHz. Due to this high switching frequency a LC filter is integrated into the module resulting in a continuous output voltage. A main topic of the paper is the active damping of this LC output filter for each module and the analysis of the series connection of the damping behaviour. The results are illustrated with simulations and measurements.

Palabras clave

  • power electronics
  • modularity
  • scalability
  • GaN
  • active filter damping

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