Switched Reluctance Motor Research Articles

Sensitivity Analysis Using the Virtual Work Principle for 2-D Magnetostatic Problems

The sensitivity analysis of electromagnetic quantities such as the magnetic force and torque is a crucial step when optimizing electromagnetic devices with gradient-based optimizers. This paper provides an analytical derivation of those two quantities using the virtual work principle in a finite element package. It is suitable for any kind of optimization. A focus on the particular use of this sensitivity on shape optimization is presented. The development and validation of the method is detailed in this case. Finally, it is applied to the shape optimization of a switch reluctance motor (SRM) to improve its performances.

Position Sensorless Control of Switched Reluctance Motors with Pulse Injecting for Two Unexcited Windings

This paper proposes a control method of switched reluctance motors without requiring position sensors. A pulse voltage is applied to the unexcited two windings and their currents are observed. By detecting the intersection between one of the currents and the other one multiplied by a certain factor obtains a signal indicating that the rotor is at a certain position. A Phase-Locked Loop block receives this signal and provides the estimated rotor position information. The switching of the winding excitation is controlled using the estimated information. Experimental results confirm that the estimated position information has almost been the same as the actual rotor angle. Moreover, load and transient tests in speed were performed and their results are presented.

Optimization design of stepped rotor type bearingless switched reluctance motor

In order to solve the problems of small starting torque and large torque ripple existing in traditional 12/14 hybrid stator pole bearingless switched reluctance motor (BSRM), a stepped rotor type BSRM is proposed. The proposed motor not only inherits the advantages of traditional 12/14 hybrid stator pole BSRM, but also can start at any rotor position and has relatively small torque ripple. To obtain better electromagnetic characteristics, simulated annealing particle swarm optimization (SAPSO) algorithm is proposed to optimize the structure of the stepped rotor type BSRM. Then, the torque, inductance and suspension force characteristics of the stepped rotor type BSRM before and after optimization are analyzed and compared. Finally, the effectiveness of the proposed optimization algorithm is verified by analysis results.

Mathematical model of stepped rotor type 12/14 bearingless switched reluctance motor based on maxwell stress method

The stator of the stepped rotor type bearingless switched reluctance motor has two kinds of wide and narrow stator teeth. The wide stator teeth provide suspension force, and the narrow stator teeth provide torque, so the decoupling control of torque and suspension force could be realized. The rotor consists of 14 rotor teeth, and the surface of each rotor tooth has a stepped structure, so that the motor can self-start from any rotor position. Although the motor with this special structure has certain performance advantages, it also leads to the complex distribution of air gap magnetic field, which brings difficulties to the establishment of mathematical model. In this paper, the integral path suitable for the stepped rotor structure is proposed and the mathematical model of the stepped rotor type bearingless switched reluctance motor is established according to Maxwell stress method. Finally, the finite element method is used to verify the correctness of the established mathematical model.

Design and Finite Element Analysis of a 6/4 Pole Multi-Layer Fully Pitched Switched Reluctance Motor to Reduce Torque Ripple

—In this study, the design and analysis of multi-layer fully pitched winding switched reluctance motor (MFP-SRM) for general use (submersible pump, electric vehicles, etc.) have been performed. It is seen that the multi-layer switched reluctance motor (SRM) has higher output power when compared to the single-layer SRM. In multi-layer SRM, the motors in the layers are electromagnetically independent of each other although they are identically the same motors with the same characteristics in terms of performance and geometry. Each layer of the MFP-SRM which is designed in this study consists of a 6/4 pole fully pitched SRM (FP-SRM) and these motors are magnetically independent of each other. In the MFP-SRM, which is designed as a double layer, there is a 15° phase difference between the rotor position angles and torque profile curves of each layer. With the phase difference that changes depending on the number of layers, each layer contributes to the total torque production of the profile, ensuring a smooth profile. According to the results of the 3D FEM analysis, it is seen that the proposed multi-layer motor structure has high starting torque and low torque ripple properties. In the analysis carried out in the range of 3–15 Amperes, the torque ripple of the traditional FP-SRM varies between 31.99% and 38.19%, while the torque ripple of the proposed MFP-SRM only varies between 3.23% and 7.11%.

An Improved Direct Predictive Torque Control for Torque Ripple and Copper Loss Reduction in SRM Drive

This paper introduces a direct predictive torque control (DPTC) method to minimize the torque ripple and copper loss of the switched reluctance motor (SRM). Generally, there is a problem with torque ripple during the SRM’s commutation. In this method, the commutation optimization is provided by a direct predictive torque control algorithm. Firstly, the reachable range of phase torques is predicted and the boundary of two continuous phases is modified. By dividing the torque range directly to determine the torque allocation set, the suppression of torque ripple becomes simple. Secondly, considering the optimization problem of copper loss during commutation, a cost function only related to the phase current is constructed. Further, the minimization of copper loss can be achieved by solving the cost function, and the work of setting weight parameters is not required. Finally, the proposed DPTC method is tested by simulation and experiment in a three-phase 12/8-pole SRM drive system and the results are compared with the existing predictive torque control methods. The results show that the proposed method has less torque ripple and copper loss, which effectively improves the torque control performance.

Sensorless control of switched reluctance motor based on a simple flux linkage model

Introduction. The operation of switched reluctance motor requires prior knowledge of the rotor position, obtaining from either low resolution photocoupler based position sensor or high resolution shaft encoder, to control the on/off states of the power switches. Problem. However, using physical position sensor in harsh environment will inevitably reduce the reliability of the motor drive, in which sensorless control comes into play. Novelty. In this paper, a sensorless control scheme of switched reluctance motor is proposed. Methodology. The method is based on a simple analytical model of the flux-linkage curves rather than the conventional approach that normally uses a look-up table to store all the data points of the flux-linkage curves. By measuring the phase current, rotor position can be deduced from the analytical model. Practical value. Simulation results are given and the proposed sensorless scheme is verified to provide a moderate position estimation accuracy in a wide speed range in both unsaturated and saturated conditions.

A Novel Motor Structure with Extended Particle Swarm Optimization for Space Robot Control.

This paper studies motor structures and optimization methods for space robots, proposing an optimized stepped rotor bearingless switched reluctance motor (BLSRM) to solve the poor self-starting ability and significant torque fluctuation issues in traditional BLSRMs. Firstly, the advantages and disadvantages of the 12/14 hybrid stator pole type BLSRM were analyzed, and a stepped rotor BLSRM structure was designed. Secondly, the particle swarm optimization (PSO) algorithm was improved and combined with finite element analysis for motor structure parameter optimization. Subsequently, a performance analysis of the original and new motors was conducted using finite element analysis software, and the results showed that the stepped rotor BLSRM had an improved self-starting ability and significantly reduced torque fluctuation, verifying the effectiveness of the proposed motor structure and optimization method.

Review on Self-Decoupling Topology of Bearingless Switched Reluctance Motor

Bearingless switched reluctance motor (BSRM) adopts a doubly salient structure without windings on the rotor. BSRMs have the advantages of high rate of fault tolerance and simple structure, high power, super high speed and strong adaptability. They have broad application prospects in aerospace, flywheel energy storage, new energy and biomedical fields. Firstly, the suspension operation mechanism of a conventional double winding BSRM is described in this paper. The coupling between torque and suspension force is analyzed with a finite element method. On this basis, from the perspective of magnetic circuit optimization of the torque system and suspension system, the magnetic circuit design, decoupling mechanism and performance characteristics of self-decoupled BSRMs with different topological structures are described centering on the self-decoupled topology form of the BSRM. Finally, the study and development of BSRMs in the future are prospected based on the research status.

Modified Whale Algorithm-Based Optimization for Fractional Order Concurrent Diminution of Torque Ripple in Switch Reluctance Motor for EV Applications

This work proposes a new multi-objective optimization technique for concurrent diminution of torque ripple with the regulation of the speed of a 75 Kilowatt, 8/6, 4-phase SRM based on a double close loop, modified whale algorithm optimized fractional order proportional integral (MWAO FO-PI) control with a commutation angle controller. The system is analyzed and designed in MATLAB/SIMULINK environment. First, the performance of MWAO is tested on 30-dimensional standard benchmark functions. It is found that MWAO performance is better when examined on 30-dimensional standard benchmark functions, compared with WOA, and another six recently proposed state-of-art functions. Then, a double loop control based on the MWAO FO-PI controller is designed and implemented for concurrent diminution of torque ripple with the regulation of the speed of a 75 Kilowatt, 8/6, 4-phase SRM with a commutation angle controller. It was found that the percentage improvement achieved in the combined objective optimization function with the MWAO FO-PI controller was 10.044% in comparison with the MWAO PI controller, and 9.0597% compared with the WOA PI controller. It is also proved that MWAO FO-PI-based double close loop control of SRM provides less torque ripple, better tracking of speed with a reference value of speed and a better current profile in comparison with the MWAO PI controller and WOA PI controller. From all the above analysis, the conclusion is reached that the MWAO FO-PI controller provides very good overall system operational performance compared with MWAO PI and WOA PI controllers. The conclusion is reached based on simulation analysis and experimental validation is lacking.

Acoustic Noise Reduction in an 8/6 Switched Reluctance Machine Using Structural Design

Today, switched reluctance motors (SRMs) represent a promising technology for the long-term sustainability of electrified transportation, mainly due to their simpler structure, lower production cost, and robust configuration compared to other motor technologies. Notwithstanding, high acoustic noise and torque ripple are two performance imperfections that have prevented the widespread implementation of SRMs. This paper presents different structural design techniques to reduce the acoustic noise of an 8/6 SRM, while maintaining the electromagnetic performance of the machine. For each technique, a corresponding multiphysics FEA analysis of the motor’s performance is presented. The accuracy of the multiphysics model is confirmed experimentally using acoustic noise measurements obtained from a four-phase 8/6 SRM. Then, several structural techniques have been investigated on the 8/6 SRM represented in two main categories: stator-housing modifications and rotor modifications. The best design strategies are then combined to improve the acoustic noise level of the 8/6 SRM while maintaining its performance.

Improved indirect instantaneous torque control based torque sharing function approach of SRM drives in EVs using hybrid technique

This manuscript proposes an improved indirect instantaneous torque control (IITC) based torque sharing function (TSF) method of switched reluctance motor (SRM) drives in electric vehicles (EVs) using a hybrid system. The proposed hybrid techniques are joint performance of both Reptile Search Algorithm (RSA) and Honey Badger Algorithm (HBA), hence it is named as Enhanced RSA (ERSA) method. Here, an IITC method of SRMs for EVs is utilized. It achieves the requirements of the vehicle, like minimum torque ripple, improved speed range, high effectiveness, and maximal torque per ampere (MTPA). To precisely specify the switched reluctance motor and its magnetic features are measured by the proposed method. The modified Torque sharing function compensates the torque error along with incoming phase, which contains the minimal rate of change of flux linkage. Finally, the ERSA method is implemented to define the best control parameters. Then, the proposed ERSA system is performed on the MATLAB platform and the performance is compared to different existing systems. The MSE for case 1 and case 2 using proposed system attains 0.01093 and 0.01095. The voltage deviation for case 1 and case 2 using proposed system reaches 5 and 5. The power factor for case 1 and case 2 reaches a value of 50 and 40 using the proposed system.

Two‐phase switched reluctance motor with hybrid excitation: Modeling and evaluation

AbstractSwitched reluctance machines offer a robust structure, inexpensive maintenance, and a low‐cost drive. However, they can suffer from low mean torque, low torque density, and high noise. Techniques such as offering the stator poles at each phase in the shape of a C core, adding several teeth to the two poles of each C‐core, and embedding permanent magnets to overcome these deficiencies are presented. Permanent magnets are embedded into the structure to create a hybrid excitation that provides a higher torque density. The C‐core stator modules of the stator are toothed to improve the torque. The radial forces on the shaft are balanced. The design procedure, operating principles, and performance trade‐offs are explained. Also, a magnetic equivalent circuit model is introduced. The model provides continuous relationships over the operating regions and incorporates core saturation and accurate flux tubes to attain high precision. Finite element models are also employed in the analysis and design process. The motor is prototyped, and experimental results are extracted, closely matching those obtained with the model and finite‐element analysis.

Design and optimization of an external-rotor switched reluctance motor for an electric scooter

In order to reduce the global carbon foot print, the need of the hour is to provide pollution free and economically viable electric vehicles (EVs) as potential alternatives to the conventional ones. Amongst the different traction motors employed in EVs, switched reluctance motors (SRMs) being magnet-free, rugged in construction and fault-tolerant is a potential forerunner for automotive applications in the near future. Therefore, in this work, an external-rotor (ER) SRM has been designed for an electric scooter application. The proposed 4-phase SRM configuration comprises of 8 and 10 poles on the stator and rotor respectively. To achieve a well-balanced design with due consideration to the various performance indicators, a multi-objective design optimization (MOO) has been performed using particle swarm optimization (PSO). The optimization was based on the results obtained from the two-dimensional (2D) electromagnetic static finite element analysis (FEA) which aimed to maximize average torque, efficiency and minimize torque ripple respectively. In comparison to the preliminary design, the optimized ER-SRM demonstrated an increased average torque and decreased copper loss by 3% and 14% respectively. The large scale of simulations performed and the results thereby obtained confirmed that the proposed SRM design met the performance demands of the electric scooter application. The average torque at the rated and the maximum speed exceeded the desired torque requirements demanded by the electric scooter by 13.1% and 42.2% respectively.

An Improved Deadbeat Control Scheme for Unipolar Sinusoidal Current Excited Switched Reluctance Motor Drives

This article reports on a novel deadbeat control (DBC) scheme to improve the current regulation performance of the unipolar sinusoidal excited control strategy for switched reluctance motors (SRMs). In this scheme, the deadbeat controller with delay compensation is first designed by using a second-order inductance-based SRM model in the rotating reference frame. This developed model can provide a more accurate description of the torque and electromagnet characteristics compared with the existing model. However, ignoring the magnetic saturation during the modeling inevitably leads to uncertainties in the proposed DBC system. To further estimate the disturbance caused by these uncertainties and improve robustness, a simple adaptive disturbance observer (ADO) based on the steepest descent method is embedded in the deadbeat controller. Then, a stability analysis based on the discrete-time Lyapunov function is used to guarantee convergence and tune the adaption gain of the proposed ADO. Finally, comparative experiments under different operation conditions are carried out on a three-phase 12/8 SRM prototype to verify the effectiveness of the proposed scheme.

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.

Based on a Novel Modular Converter, Modular Battery Management for SRM drives in Hybrid Vehicles

Abstract: In order to address environmental issues, the automotive industry is moving in a significant direction towards hybrid vehicles. One of its primary drive system options is a switching reluctance motor (SRM). This article designs a brand-new SRM converter topology. The innovative converter can manage battery energy and implement multi-level control. The battery control circuit is created in a modular manner, allowing the number of battery modules (BMs) to be chosen based on system needs. A hybrid vehicle's driving conditions are used to separate the converter's status into five states and conduct detailed analyses of each. Ultimately, the novel converter's simulation model and testing platform are constructed. The findings of the simulation and experiment confirm the viability of various working modes of the system's fault tolerance and reliability have been considerably enhanced by the innovative converter topology and the ability to individually regulate each BM.

Consensus control of semi‐Markov jump topology multiple direct‐drive motion system

AbstractRandom jump of network communication topology challenges the tracking accuracy of linear switched reluctance motor (LSRM) system. This paper studies the pilot‐following consensus control of the multiple direct‐drive motion system (MDDMS) with semi‐Markov jump topology. The mathematical model of LSRM is constructed and the multi‐phase excitation strategy is studied. The directed graph is used to model the information transmission among the leaders and follower, and a new mechanism consensus based on previous states is provided. A consensus system based on semi‐Markov jump topology is constructed and the problem of consensus is shifted into a problem of stability analysis. A sufficient condition for consensus problem is obtained by using semi‐Markov switching system theory and graph theory. The MDDMS achieves consensus in the form of exponential convergence under the designed consensus controller. Several groups of simulation results verify the effectiveness of the proposed consensus control method.

Selection, Design and optimization of Switched Reluctance Motor Drive System for E-Rikshaw Application

Selection, Design and optimization of Switched Reluctance Motor Drive System for E-Rikshaw Application

Current Status and Prospects of Electric Motor Applications for Electric Vehicles

Nowadays, with the global pursuit of zero emissions, the trend of automobile electrification is very rapid. The drive motor is the core component of electric vehicles, which has an important impact on the working life and performance of electric vehicles. Therefore, all major manufacturers are trying to find and develop better and more efficient motors. At present, the research on driving motor has become a hot issue in the field of electric vehicles, attracting many scholars to carry out a lot of research work. This paper analyzes four common driving motors in the market, discusses their structure, principle and performance, and lists their advantages and disadvantages for comparison. Then it describes the development status of various types of motors and their applications in electric vehicles, and introduces the prospects of electric vehicle motors and suggestions for improvement of switched reluctance motors.