Control Of Switched Reluctance Motor Research Articles

Modified switching control of SRM drives for electric vehicles application with torque ripple reduction

The switched reluctance motor (SRM) offers extensive prospects, particularly within the realm of electric vehicles (EVs). Its robust construction, wide speed range, high torque density, and efficiency provide significant advantages that surpass other motors. Nonetheless, controlling these motors is more intricate when compared to conventional DC brushed or AC motors. This complexity arises due to the non-linear inductance characteristics of SRMs, resulting in undesirable effects like torque ripple, vibrations, and noise. Using the conventional full-bridge inverter, three switching approaches are highlighted for various operating modes of an EV. This aims to reduce costs and the number of switching pulses, leading to a more compact system, elimination of dead time, and switching losses. The MATLAB/Simulink platform was utilized to examine the operational effectiveness of a three-phase 6/4 poles SRM drive. Additionally, this paper focuses on mitigating torque ripple concerns by employing an adaptive neuro-fuzzy inference system (ANFIS) controller that has better efficiency and superior responses compared to conventional controllers such as fuzzy logic control (FLC) and proportional integral (PI) control. The results of the simulation encourage the practical implementation of the system, which is the next step in the author’s research.

Maximum Torque per Ampere Technique for Switched Reluctance Motor Drive

Numerous researchers have investigated switched reluctance motors (SRMs) as a competitor to other electrical motors for usage in electric and hybrid vehicle appliances. SRMs are fault-tolerant and have a broad operating speed range. However, they have numerous drawbacks, such as high nonlinearity in machine models, complex control, and torque ripple. This study aims to improve the SRM drive system to attain maximum torque per ampere in a wide speed range. In the design and control of SRMs, maximizing torque per ampere (MTPA) is a crucial objective. MTPA refers to the strategy of achieving the maximum possible torque output for a given current input (amperes). This is essential for enhancing the efficiency and performance of the motor. The paper focuses on achieving MTPA in an SRM drive system-based commutation angle control. Utilizing a bacterial foraging optimization algorithm (BFOA), the suitable commutation angles at each operation point are determined. The intended technique is straightforward to realize and does not require complex algorithms. Simulation comparisons on an 8/6 SRM are also presented to validate the intended control technique. The results indicate that the MTPA has been enhanced by 6.961% compared to the conventional method.

Direct Instantaneous Torque Control of SRM Based on a Novel Multilevel Converter for Low Torque Ripple

The torque ripple of a switched reluctance motor (SRM) limits its application in electric vehicles. This paper proposes a DITC system for SRMs based on a novel multilevel converter (MLC), which aims at the problem that the torque ripple cannot be effectively suppressed for the conventional direct instantaneous torque control (DITC) of an SRM due to the limitation of the DC bus voltage in the asymmetric half-bridge converter (AHBC) and the single control strategy formulated in the commutation region. Based on the advantages of fast excitation and fast demagnetization for the proposed MLC and the torque distribution characteristics for each phase winding in the commutation region, a novel torque hysteresis control strategy is developed to improve the torque-following ability of the DITC and achieve the purpose of minimizing the torque ripple in the commutation region. In addition, multiobjective optimization control of the motor is carried out to improve the efficiency of the DITC system while suppressing the torque ripple. The effectiveness of the proposed SRM drive scheme is verified by experiment, which is of great significance for the application of SRMs in electric vehicles.

Two-phase switched reluctance motor drive control system design

The two-phase switching reluctance motor drive control system uses STM8S003F3 as the control chip to realize the control function. The hardware circuit is mainly composed of switched reluctance motor controller power and relay control circuit based on an asymmetric half-bridge circuit, a drive circuit module based on IR2101S, a rotor detection module based on a photoelectric sensor, current detection and protection circuit based on Hall current sensor, power supply circuit based on the multi-integrated chip. The control system has been significantly improved in safety and reliability.

Comparative analysis of switched reluctance motor control algorithms

Nowadays it has become possible to develop inexpensive modern control systems for nonlinear complexity electromechanical objects due to the development of microprocessor technology and power electronics. Switched reluctance electric machines are among these devices. It makes it possible to widely use such electric machines in various practical implementations, in particular, in traction drives, electric drives of oil and gas drilling rigs, and in other applications. The switched reluctance electric machine is a non-linear object, and its control methods require formalization and grouping. The manuscript considers the design and functional features of switched reluctance electrical machines. The main methods of controlling these electrical machine types are given. Comparative analysis of the most known methods is carried out. The main classical methods of switched reluctance electric machine control are considered, such as a relay current controller with a limitation, the method of controlling the turn on/off angles and controlling the DC link voltage. Transient responses in the electric drive system are demonstrated using the considered methods. It is shown that by adjusting the on/off angles, it is possible to reduce the torque oscillation coefficient. The identified features of the presented methods will make it possible to simplify and reduce the development time for an effective control system for switched reluctance electrical machines as well as to reduce the torque ripple.

Simulation and Optimization for Position Servo Control System of Switched Reluctance Motor

Switched reluctance motors are widely used in household appliances, textile machines, electric vehicles, and other fields due to their simple structure, low cost, high reliability, high efficiency, large starting torque, and wide speed regulation range. With the continuous expansion of the application field of SRM, higher requirements are put forward for the design of the motor position servo control system. The control system should be highly accurate and easy to deploy and have strong anti-interference. Based on the traditional switched reluctance motor control method, this paper designs a feedforward control position loop and applies CVC control at low-speed conditions to optimize the accuracy, anti-interference, and torque ripple characteristics of position servo control. The simulation results prove that the design results of the servo control system are correct and effective.

Phase Current Reconstruction Method With an Improved Direct Torque Control of SRM Drive for Electric Transportation Applications

Acquisition of the accurate phase currents is indispensable for the control and protection of switched reluctance motor (SRM) drives for electric transportation applications. Existing phase current reconstruction techniques for SRM are implemented under the current control techniques, which generate large torque pulsations. Therefore, the direct torque control (DTC) method can be adopted to minimize torque pulsations and to enhance transient performance in electrified vehicles. However, the existing current estimation methods cannot be applied to DTC strategies due to the simultaneous conduction of all phases at any switching instant. Furthermore, it offers a lower torque per ampere ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$T/A$</tex-math></inline-formula> ) ratio and draws a high source current. This article addresses the aforementioned concerns by proposing a cost-effective phase current reconstruction method with an improved DTC strategy for a 4-kW four-phase SRM drive. This method employs a 16-sector partition method with a new voltage vector selection by detecting zero-current regions of each phase. As a result, the long-tail currents can be avoided, thereby limiting the simultaneous conduction of all phases. The simulation and test results show that the proposed DTC has minimal torque pulsations, high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$T/A$</tex-math></inline-formula> ratio, low converter losses, and lower source current ripple in comparison to the existing DTC schemes under various operating conditions. Also, the proposed phase current estimation method effectively reconstructs the phase currents under both steady-state and transient operating conditions.

Design of a Deflection Switched Reluctance Motor Control System Based on a Flexible Neural Network

Deflection switched reluctance motors (DSRM) are prone to chattering at low speeds, which always affects the output efficiency of the DSRM and the mechanical loss of the motor. Combining the characteristics of a traditional reluctance motor with the strong nonlinear and high coupling of the DSRM, a control system for a DSRM based on a flexible neural network (FNN) is proposed in this paper. Based on the better robustness and fault tolerance of fuzzy PI control, the given speed signal is adjusted and converted into a torque control signal. As a result, the FNN control module possesses the strong self-learning ability and adaptive adjustment ability necessary to obtain the control voltage signal. Through simulations and experiments, it was verified that the control system can run stably on DSRM and shows good dynamic performance and anti-interference ability.

Position Sensorless Control of Switched Reluctance Motor Drives Based on a New Sliding Mode Observer Using Fourier Flux Linkage Model

This paper proposes a new position sensorless method for switched reluctance motor (SRM) drive control based on a sliding mode observer using nonlinear Fourier flux linkage model. First, to obtain an accurate mathematical model of SRM for establishment of sliding mode position observer (SMPO), an analytical method based on Fourier polynomial function is introduced to regress the nonlinear relationship between flux linkage, position and current. Then, a new SMPO is designed in detail to estimate the rotor position, including the establishment of SRM model of sliding mode observer, and analysis of estimation error and convergence conditions of SMPO. Finally, position sensorless control of SRM drive based on SMPO is carried out in terms of accuracy and robustness in simulation. Experiments are also given on a dynamic testing platform to verify the effectiveness of the proposed position sensorless scheme.

Simulation analysis of SR motor speed regulation system based on PI control

The switching reluctance motor speed regulation system (SRD) will produce more serious nonlinear problems when running, and the current conventional solution is analyzed and discussed as a PI control method(HE 2008). Based on the SR motor model included in Matlab/Simuliunk simulation system, the simulation results are obtained by using the comparison method with or without PI control, and the advantages and disadvantages of the PI control method are analyzed to achieve the requirements for the switched reluctance motor control system.

Unipolar sinusoidal current excited switched reluctance motor control based on a 3D space vector modulation

This paper reports on a novel unipolar current excited control scheme for the asymmetric bridge converter (ABC)-based switched reluctance drive (SRD), where the 3D space vector modulation under three modes is developed to reduce the total harmonic distribution (THD) and torque ripple. Firstly, two different 3D vector distributions, namely, the small voltage amplitude mode and large mode are presented based on the asymmetric converter. For both distributions, the zero-sequence voltages generated by the effective vectors are considered. Additionally, zero-sequence vectors (1,1,1) and (−1,−1,−1) are no longer treated as null vectors and involved in the control of zero-sequence current. Then, the duty cycles of both two modes are obtained by the combination of the zero-sequence and two adjacent active vectors. Moreover, based on the large modulation mode, a novel method combined with the small mode is proposed to further optimise the switching costs and torque ripples. The effectiveness of the proposed modes is verified through the simulation in MATLAB and the experiment on a dSPACE-1103-based prototype. Compared with the conventional switched reluctance motor vector control, the proposed scheme delivers better performances of THD, efficiency and torque ripple reduction.

Position-Sensorless Control of Switched Reluctance Motor Drives: A Review

Switched reluctance motors (SRMs) are promising traction machine candidates for electric vehicle powertrains and industrial driving systems due to their rugged construction and high efficiency. Precise speed and torque control of SRMs require real-time rotor position information from mechanical position sensors. With the advantages of lower costs and position sensor fault-tolerant capability, various position-sensorless control strategies have been developed for SRM drives in the past decades. This article presents a review of the state-of-the-art sensorless control schemes over a wide speed range. Low-speed methods based on high-frequency pulse voltage injection and high-speed methods based on fundamental excitation are summarized to give readers a systematic categorization. An in-depth comparison of major sensorless control algorithms in estimation accuracy, robustness, universality, and parameter sensitivity is presented. Finally, the existing challenges and future trends are discussed.

Optimal Design of Terminal Sliding Mode Controller for Direct Torque Control of SRMs

A nonsingular terminal sliding mode controller (NTSMC) based on a direct torque control is presented for a switched reluctance motor (SRM) in this article. To guarantee dynamic stability, the nonsingular terminal sliding mode based on an improved reaching law (RL) is employed to design the speed controller. The torque ripple of the system can be suppressed, and the disturbance caused by uncertainties, such as load disturbance and parameter perturbation, can be suppressed by the proposed NTSMC. Moreover, the gray wolf optimization algorithm is applied to automatically adjust the parameters of the controllers and the value of given flux, thereby acquiring a satisfactory result. The NTSMC is validated by both simulation and experimental results with a six-phase 12/10 SRM. Compared with PI and conventional sliding mode control, NTSMC improves the convergence rate of state and exhibits better performance in torque ripple reduction and antidisturbance ability. The robustness and dynamic performance of the system can be ensured.

A Nonlinear SRM Controller Design for Torque Ripple Reduction with accounting for Magnetic Saturation

In this paper, a nonlinear backstepping controller design is proposed for torque ripple minimization in switched reluctance motor (SRM) drive systems, which ensures less acoustic noise and less vibration. The proposed controller is based on a model taking into account the stator coils magnetic saturation phenomenon. For the torque ripple optimization purpose, the excitation angles are adapted according to the instantaneous SRM torque and speed values. Therefore, a lookup table is built, proposing the excitation angles optimal values for different machine operation points. The proposed control strategy validation was carried out by simulation, using MATLAB-Simulink tools. More specifically, the Simpower system library was exploited, since it offers an SRM simulator, taking into account magnetic saturation. To highlight the supremacy of the proposed controller, its performances are compared with those of conventional linear (PI) regulator. The obtained results validate the proposed controller robustness and efficiency.

ANFIS based speed and current control with torque ripple minimization using hybrid SSD-SFO for switched reluctance motor

SRM (Switched Reluctance motor) is gaining much interest in industries due to its straightforward structure, low-cost manufacturability and dependability which makes it better than other electric machines. SRM drive is the most appropriate for variable speed tasks. Additionally, the performance of the current and speed control for the SRM driver framework could be negatively influenced by noise, disturbances, and inactivity of load torque. To solve this difficulty, this paper develop an ANFIS based Speed and Current control with Torque Ripple Minimization using Hybrid SSD-SFO for SRM. The main goal of this work is to obtain preferred current and speed performance of SRM with minimum torque ripple. For concurrent regulator of the speed and current, an ANFIS (Adaptive Neuro-Fuzzy Inference System) structure is employed which includes two controlling loops. The inside loop is regulated for control of current and the outside loop is regulated for control of speed even with perfect choice of switching angles. The dynamic conduct of SRM is studied to restrict the current and speed that reduces the ripple of torque. Hybrid SSD-SFO (social ski-diver based sunflower optimization) procedure is employed to achieve the parameter values of current and speed control of SRM. The proposed scheme is accomplished by MATLAB/ Simulink environment. The results show that the hybrid SSD-SFO scheme given the better performance compared to the SSD and SFO algorithm.

Optimum Switching Angles Control of SRM for Electric Vehicle Applications

Switched Reluctance Motor (SRM) drive is being gradually used in industrial applications, including electric vehicles (EVs), due to several advantages over conventional motors. However, the nonlinear magnetic characteristics of the motor make its controller very complicated. This paper presents a simplified procedure to obtain the optimal switching angles under hysteresis current control SRM drive over a wide range of speeds. A multi-objective optimization technique is applied to determine the optimal switch on and switch off angles that achieve the optimum combination of maximum average torque with minimum torque ripple and copper loss. A searching algorithm is developed for each operating point to define the maximum average torque and the minimum torque ripple and copper losses, as they vary for different currents and motor speeds. Then the optimal values of switching angles are stored in the lookup tables to build a MATLAB model of the SRM drive system. Finally, simulation and experimental results are presented to show the validity and effectiveness of the proposed controller.

Torque Ripple Suppression Control of Vector-Controlled Switched Reluctance Motors

For the switched reluctance motor (SRM), it is difficult to derive optimum control parameters to suppress vibration and noise. In previous studies, to suppress the torque ripple, which is one of the causes of vibration, it was necessary to derive control parameters by trial and error, for example, by using finite element analysis. Thus, vector control specialized for the SRM has been proposed to simplify the construction of the control system. This paper proposes torque ripple suppression control of the vector-controlled SRM. In the proposed control method, the torque ripple is suppressed by feeding back the estimated torque to the reference torque by considering its harmonic components; the torque ripple can then be suppressed with a simple controller configuration. It was experimentally observed that the sixth harmonic component of the torque is suppressed by a maximum of 74.0% compared with that obtained in the conventional control method.

Artificial Intelligent Controller-Based Speed Control of Switched Reluctance Motor

A new control methodology for controlling the speed of switched reluctance motor (SRM) drive using an intelligent controller is proposed in this paper. The control technology consists of an outer loop fuzzy controller as a speed controller and hysteresis current controller as the inner control loop along with control of switching angles for the four-phase, 8/6 SRM. In this proposed method, the speed control is optimized using the randomly determined fuzzy parameters. Fuzzy interfaced speed control of SRM is simulated using MATLAB/SIMULINK software. The robust performance of the fuzzy logic controller is valued using the least combinations (matrix) of rules for wide ranges of speed and is compared with the proportional-integral (PI) controller. Simulation results reveal that fuzzy-based speed controller gives enhanced performance in the form of quick speed response varies between 0.02sec to 0.12 sec over an extensive range of speed thereby improving the dynamic efficiency of the SRM drive.

A Simple Method to Control The Excitation Angle for Switched Reluctance Motor

A switched reluctance motor (SRM) has been an alternative solution for electric drives because of its benefit features. The use of such a motor in electric vehicles (EVs) or hybrid electric vehicles (HEVs) requires a control strategy that is capable to develop high torque. SRMs are commonly available in the market with rotor position detectors embedded inside. Problems will appear when such detectors are not symmetrically installed because most of SRM control strategies are commonly based on them. Inaccurate pulses will be generated by the control circuit which finally takes effect on phase current commutation or the beginning of the excitation which is not on proper angle. The use of such detectors is just capable to give information of rotor position in common angles. Improvement for such problems can be done by generating pulses related to the rotor position in smooth angles. In this paper, a control strategy to produce excitation signals with proper angles for SRM stator winding is proposed. By using input capture facility that is commonly available in embedded system, excitation angles can be controlled precisely because a large number of pulses can be produced by the system. Accuracy level of this strategy is determined by TIMER period of embedded system and speed of SRM. To verify the analysis, laboratory experiments were done. They show that the proposed control strategy is capable to rotate the motor with better performance.

Torque ripple and noise control of switched reluctance motor using an adaptive fuzzy PI control with the aid of AR algorithm

In recent days switched reluctance motor is widely used for numerous industrial applications due to its simple structure, minimum cost and maximum efficiency. Regardless of numerous exclusive benefits of the switched reluctance motor (SRM), acoustic noise of this motor is high and it is important to accomplish more analysis on the noise lessening, which is the primary goal of this paper. The major causes of acoustic noise in a SRM are torque ripple and radial magnetic force. Since radial magnetic force is highly influential by the design of motor, torque ripple control is analysed in this article for acoustic noise control. Torque ripple control of SRM is proposed using optimization in direct torque control (DTC) method. Nowadays, optimisation plays a crucial role in motor drives for enhanced control. In this paper, artificial raindrop algorithm is proposed in DTC of SRM to minimise torque ripple. Performance of proposed ARA based DTC of four-phase 8/6 SRM is analysed using Matlab and compared with the performance of fuzzy gain scheduling PI controller based DTC.