Pole Switched Reluctance Motor Research Articles

Sensorless control using single current sensor with PFC assisted SRM drive for cost-effective domestic appliances

This paper presents a sensorless control designed for low to medium speed operation of an 8/6 pole switched reluctance motor (SRM) drive, utilizing only a single current and voltage sensor while ensuring grid-side power quality. It emphasizes a cost-effective solution suitable for low-power applications in both domestic and industrial appliances, employing SRM drive technology. In this, AC input is fed to Cuk converter that suppresses grid current total harmonic distortion (THD). Using symmetrical structural properties of SRM allows for a cost-friendly sensorless control approach. Position estimation for four-phase SRM is achieved by comparing two-position reference fluxes with running flux. In case of four-phase SRM, phases A and C are conducted sequentially, enabling a single voltage and current sensor to estimate flux for both phases. This method contrasts with lookup table-based rotor position estimation, requiring only two sets of position flux data, thus reducing memory usage, controller complexity, and speeding up response. A laboratory prototype of a four-phase 8/6 SRM is used to estimate rotor position in sensorless control. Finally, test results are used to validate effectiveness of presented PFC assisted sensorless control approach.

Co‐excitation control of a four‐degree‐of‐freedom magnetic bearing switched reluctance motor based on mathematical models

AbstractIn traditional magnetic bearing motors, the magnetic bearing and the motor are usually driven and controlled separately, resulting in higher controller costs and limiting further expansion of their applications. The author presents a four‐degree‐of‐freedom (4DOF) magnetic bearing switched reluctance motor (MBSRM), consisting of two 8‐pole active radial magnetic bearings (RMBs) and two two‐phase 4/2‐pole switched reluctance motors (SRMs), driven simultaneously by a set of asymmetrical power converters together. Firstly, the structure, winding configuration and co‐excitation working principles of the 4DOF‐MBSRM system are described in detail. Then the radial force formula for an 8‐pole RMB and the torque mathematical model for a 4/2‐pole SRM are briefly derived based on equivalent magnetic circuits, respectively. Furthermore, a co‐excitation control strategy for the 4DOF MBSRM is developed wherein an instantaneous radial force is used to control its rotor shaft levitation, an instantaneous torque is employed for rotational control at low and medium speeds, and an average torque is used for high speed operation. Finally, the good performance of the co‐excitation control for the proposed 4DOF‐MBSRM is proved by simulation analysis.

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.

Modal Analysis of an 8/6 Pole Switched Reluctance Motor Core with Different Materials and Assembly Method Using FEA

Vibration causes acoustic nuisance, aggravating fatigue etc. Knowing that resonance is caused by amplified deformation when a structure is excited at natural frequency, modal analysis is important to identify the natural frequency and mode of deformation that may be excited in electrical machine. This study analyzes the natural frequency and mode shape of major components in 120v 4-Phase 8/6 Pole Switched Reluctance Motor. The material selected are materials that are commonly employed for electrical machines components. It was found that gray cast iron core has the lowest natural frequency for each mode from 1 to 3. This is mainly due to its lower elasticity modulus (10 times smaller in comparison to other materials). Solid and slinky rotor has a very low first mode natural frequency at tens of Hz, which is very susceptible to mechanically induced excitation vibration.

Fuzzy Controller Based DTC of SRM Drive Fed by Common High Side Asymmetric Switch Converter

The switched reluctance motor (SRM) is recently gaining huge popularity in electric vehicle (EV) applications due to its control flexibility, simple structure, lower cost and high efficiency than the synchronous and induction motors. Among all the controllers, the direct torque control (DTC) is the most preferred due to its higher efficiency, lower losses and superior control characteristics. In this paper, a 6/4 pole SRM with fuzzy logic based DTC has been proposed for the EV application along with a converter with reduced switch counts to reduce the torque ripples and enhance the performance of the system under steady and transient state conditions. The proposed system is tested and validated under various scenarios that include load torque and speed variations and compared with the vector control method. From, the investigation it has been found that the proposed technique reduces ripples from the system during all the scenarios with a resultant flux of less than 0.5pu.

Current Optimization Control of Switched Reluctance Motor for Low Speed Range

In this paper, two different strategies are combined to optimize the phase current control for switched reluctance motor (SRM). Firstly, considering the sampling and computation delay, a current prediction chopping control method is proposed to alleviate the current ripple during the entire excitation phase chopping process. Secondly, in order to cut down the large current ripple in the initial stage of phase current establishment and the excessive output current of the battery, a partitioned current control method is proposed to control the phase current with different control logic at different rotor zones. Finally, the two control strategies are combined to further optimize the phase current. In order to verify the proposed combined control strategy, a three-phase 12/8 poles SRM simulation model and experimental platform are built. The simulations and experiments are carried out to verify the effectiveness of the proposed control strategy.

A unified control method combined with improved TSF and LADRC for SRMs Using modified grey wolf optimization algorithm

This paper proposes a unified control method based on an improved grey wolf optimization algorithm to improve the performance of the switched reluctance motors (SRMs) to cope with various operating conditions. Compared with the single control mode of traditional SRMs, an SRM with 12/10 poles is called a multimode switched reluctance motor, which can be used not only as a six-phase motor but also as a three-phase motor. The control method proposed is based on a 12/10 pole SRMs. In the TSRM mode, an improved torque sharing function with parameters is utilized to reduce torque ripple and widen the speed range. In the SSRM mode, the linear active disturbance rejection control (LADRC) method is used to increase the anti-interference ability of the system. For the switching modes, an improved gray wolf optimization algorithm is designed to ensure smooth switching. The global optimal solution is obtained by introducing the coyote group to avoid falling into the local optimal solution. Finally, the experimental results prove the effectiveness of the control method.

Performance Improvement of a Switched Reluctance Motor and Drive System Designed for an Electric Motorcycle

In this paper, the implementation of a switched reluctance motor (SRM) and drive system for the propulsion system of a two-seat electric motorcycle is described. The overall design focuses on the required vehicle speed, acceleration, driving distance, and overall system cost, as well as reliability. The performance of the three-phase 6/4 pole (six-stator pole and four-rotor pole) and four-phase 8/6 pole (eight-stator pole and six-rotor pole) are investigated and compared by static performance analysis and dynamic performance analysis. Their performance is further investigated by finite element analysis. The indirect torque controller in a drive system for optimal torque and efficiency operation is also mentioned. A methodology for rotor position detection and its hardware implementation are also proposed. The designed 3.5 kW three-phase 6/4 pole SRM and its drive system were constructed and tested on the test bench. A maximum efficiency of about 82% could be achieved for the SRM and drive system. It was also installed on a 120-cc electric motorcycle, and the vehicle’s performance was also validated by on-road and dynamometer testing. The maximum vehicle speed reached was 82 km/h, and a cruising distance of about 98 km at a constant speed of 40 km/h was measured.

Minimization of torque ripple in switched reluctance motor based on MPC and TSF

In this paper, a novel control method based on model predictive control (MPC) and torque sharing function (TSF) is addressed to minimize the torque ripple of switched reluctance motor (SRM). Firstly, an accurate SRM model is established based on flux‐linkage characteristic curves obtained from the locked rotor test, which can predict the future operation state of the SRM drive system. Secondly, an improved TSF curve is proposed, and genetic algorithm is used to optimize TSF parameters to reduce torque ripple in commutation region. Besides, the MPC is integrated into the TSF control framework to replace the traditional hysteresis controller, and establishes a new TSF‐based model predicted torque control (MPTC) method, which avoids the frequency conversion problem caused by torque or current hysteresis controller. Further, a sector division scheme is addressed to decrease the number of candidate voltage states, whereby the computation of the controller in each sampling period is effectively reduced. Finally, in order to verify the correctness of the MPTC method, it is compared with the traditional direct instantaneous torque control (DITC). Both simulations and experiments on a three‐phase 12/8 pole SRM have confirmed that MPTC scheme can not only decreases torque ripple and stator copper losses, but also has higher efficiency than DITC. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Influence of Control and Structure Parameters on the Starting Performance of a 12/8 Pole Switched Reluctance Motor

To investigate the influence of control and structure parameters on the starting performance of a switched reluctance motor, a 12/8 pole switched reluctance motor is analyzed in this paper. The novel field-circuit coupled finite element method of switched reluctance motor is proposed in the paper. The influence of the controller on the switched reluctance motor is considered. The influence of rotor initial position angle, starting mode, starting current, and structure parameters on the starting performance of the switched reluctance motor is studied using the field-circuit coupled finite element method. The starting performance of the switched reluctance motor is obtained under the different control and structure parameters. The alternating starting mode of single- and two-phase winding can improve the starting torque of switched reluctance motor (SRM). As the stator pole arc coefficient increases, the starting torque of SRM increases. The appropriate reduction of the air gap length can improve the starting torque of SRM. Experimental results of the prototype are compared with the calculation results, which verifies the reliability of the calculation method and accuracy of the calculation results.

A New Constructed Geometry of A Switched Reluctance Motor for Reduced Torque Ripple (Dept.E)

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Realization of fault tolerant capability in a multiphase SRM drive using wavelet transform

Switched Reluctance Motor (SRM) are widely used in drives market because of its elegant features such as simple arrangement, manufacturing cost, minimal maintenance and wide speed range. Significant investigation has been conducted to lengthen the feasibility of SRM drive technologies in various aspects such as control strategy, torque ripple minimization, an optimal winding arrangement, etc. Even though it has numerous virtues, there are few noticeable issues that occur in SRM. In this paper, the issues like phase open circuit fault, phase-phase short circuit fault, power switch failure, dc link capacitor failure, and encoder faults are discussed using Wavelet Transform (WT) with their experimental results. A multi-phase (10/8 pole) SRM motor is considered to investigate the fault tolerance proficiency and other performance parameters. Initially, a healthy condition of multi-phase SRM is simulated then faults are injected at different phases which are analyzed and validated using MATLAB simulink tool and the same is validated through experimental results. The performance parameters of SRM drive during various faults conditions are analyzed and the impacts of speed and torque are illustrated.

An Integrated SRM Powertrain Topology for Plug-In Hybrid Electric Vehicles With Multiple Driving and Onboard Charging Capabilities

Plug-in hybrid electric vehicles (PHEVs) possess the merits of low carbon emissions, high fuel efficiency, and long driving mileage, and thus attract more and more attention. This article presents an integrated switched reluctance motor (SRM) powertrain topology for PHEVs, which owns multiple driving and battery-charging functions with less power electronic devices than traditional topology. In motor driving mode, four driving modes are achieved according to the road conditions. Motoring and braking operations can be successfully implemented. For battery-charging mode, three charging modes are implemented without extra battery chargers. A three-channel interleaved boost converter with power factor correction (PFC) capability is constituted by utilizing the SRM windings and integrated converter circuit to charge the traction battery from the grid. An integrated half-bridge isolation dc/dc converter is employed to charge the auxiliary battery from the generator or traction battery. A proof-of-concept prototype platform is built and experiments are carried out on a three-phase 12/8 poles SRM to verify the effectiveness of the proposed integrated drive topology and the corresponding control schemes.

Transverse nonlinear vibration of the eccentric rotor in a 12/8 switched reluctance motor

PurposeTo investigate transverse vibration of the eccentric rotor in a 12/8 poles switched reluctance motor (SRM), a transverse analytical vibration model is built by finite element method (FEM) under the interaction of radial magnetic resultant and vibration displacement. External forces, including radial magnetic resultant and centrifugal force, are also derived in detail, according to the variation of airgap and current and other intermediate parameters with rotation angle.Design/methodology/approachThe transverse vibration response of the eccentric rotor including radial magnetic resultant and vibration displacement is solved by Newmark-β method, after inputting the currents of three phase windings under angle position control strategy. The basic characteristics of radial magnetic resultant and vibration displacement are reflected in time and frequency domain.FindingsThe magnetic resultant vector of the eccentric rotor presents multi-petals star geometric shape. The frequency distribution of magnetic resultant relates to rotation speed, current waveform and the least common multiple of the stator and rotor teeth. However, the frequency distribution of the vibration displacement also relates closely to the first-order critical whirl speed of the rotor. When the rotor is running at certain speeds, it will display superharmonic resonance and show abundant displacement locus.Originality/valueBy using this analytical model and solving process proposed in this paper, the nonlinear coupled vibration response of the eccentric rotor in SRM can be analyzed and discussed rapidly; only the stator’s winding currents obtained by experiment or electromagnetic simulation is needed as input.

An Integrated Electrified Powertrain Topology With SRG and SRM for Plug-In Hybrid Electrical Vehicle

With the advantages of less carbon dioxide emissions and high fuel efficiency, plug-in hybrid electrical vehicle (PHEV) is an attractive means of transportation. This article presents an electrified powertrain for PHEV containing switched reluctance generator (SRG), switched reluctance motor (SRM), and integrated power converters, which could achieve various driving and flexible on-board charging functions. The operation states of SRG and SRM with the integrated topology is analyzed. Five driving modes for PHEV are implemented and can be smoothly switched by controlling the front-end converter according to the load conditions. For the PHEV charging mode, a single-phase ac–dc rectifier is constituted by the windings and power converter of SRG with the capability of input power factor correction. The traction and auxiliary batteries chargers are formed by the windings and power converter of SRM. Three charging modes also are achieved and no complex control strategies are required to avoid the rotation of rotors. The three-phase 12/8 poles SRG and SRM experimental platform are built. The experiments are carried out to verify the effectiveness of proposed integrated powertrain and the corresponding control schemes.

Design and Analysis of 4 Kw Srm Drive for Air-Conditioned Pwm Rectifier and Buck-Boost Pfc Converter

In domestic applications like air conditioners Buck or Cuk converter fed by Permanent Magnet Brushless DC Motors (PMBLDCM) are applicable in literature. Due to drawbacks of economical factor and non availability of permanent magnets these motors are not preferable in these days and are compensated by using Switched Reluctance Motor (SRM) as it has benefits of simple design and low cost. For domestic applications accessible input is AC, a diode bridge rectifier is a simple way of converting AC to DC but it produces lower order harmonics, a low power factor on supply side and variable DC on DC side. In order to overcome this problem PWM rectifier and Buck-Boost Converters are proposed for harmonic mitigation and power factor modification. This paper describes the design analysis (calculations) of 200V, 4KW, 2500 RPM 6/4 pole SRM. Analysis is carried out for SRM drive in air-conditioner (ac) application with PWM rectifier and Buck-Boost converter (BBC) for Power Factor Correction and harmonic mitigation. In proposed work the analysis was carried out for 6/4 SRM with various conditions like initial condition, step variation in dc link voltage, at fixed DC link voltage and variation in source voltage. MATLAB/SIMULINK model of SRM drive for different conditions said above were developed and results were also discussed in this paper. Voltage and current waveforms representing power factor is shown for the SRM drive system with PFC- PWM rectifier and Buck Boost converter. Comparison between proposed converters fed SRM and existing converters like Buck, Cuk converter fed PMBLDCM and Zeta converter fed SRM were given along with their THD. THD was reduced and limited within IEEE standards when operating SRM drive with PFC converter.

Novel Switched Reluctance Machines for Domestic Appliances

Switched reluctance motors (SRM) are the core components of household appliances, which directly affect the performance and quality of household appliances. We have studied the application of switched reluctance motors in the home appliance industry. The 12/8-pole three-phase switched reluctance motor with a new rotor structure was proposed for the performance of SRM and the performance is simulated by MATLAB tools. Besides, the control principle and the operating equations of the switched reluctance motor are also introduced and deduced in detail. For the further work, although the 12/8 pole switched reluctance motor can effectively reduce the torque ripple, it cannot be completely eliminated. Therefore, the next step should continue to explore ways to reduce torque ripple.

The Design of Flux Linkage Measurement for Switched Reluctance Motor

A Back Propagation neural network (BPNN) flux linkage model was proposed based on the measured magnetization curve for 8/6 poles switched reluctance motor (SRM). A flux linkage measuring installation is set up by using a digital signal processor (DSP) and measuring the voltage of winding under different rotor positions and different current values, then obtained the value of the corresponding flux linkage and the rotor magnetization characteristics of different positions.The flux linkage has higher accuracy. The design has the actual reference value to the high performance speed control of SRM.

A New Control Method Based on DTC and MPC to Reduce Torque Ripple in SRM

This paper proposes a new control strategy to reduce torque ripple in a switched reluctance motor (SRM). The flux linkage in this paper is related to model predictive flux control (MPFC). In addition, the torque hysteresis remained in the system is similar to direct torque control (DTC) and direct instantaneous torque control (DITC). The candidate voltage vectors (VVs) are selected from the torque hysteresis and the cost function is designed for the flux linkage minimization to select the best VV from candidate VVs. The advantages, as well as the improvement prospects for these methods, are discussed in details. Performance for torque ripple in steady state and the robustness in the transient state are evaluated in this paper under the simulation and experimental results, and also the possibility and some advice for model predictive control (MPC) applied to an SRM are indicated. The experimental result for the new method is carried out on a three-phase 12/8 poles SRM with the analysis of torque ripple compared to a DTC and DITC.

Lateral Superharmonic Resonance of the Rotor in 12/8 Poles Switched Reluctance Motor

Switched reluctance motor (SRM) generates a very large electromagnetic radial force when the stator windings commutate because of its doubly salient structure and magnetic saturation. Lateral vibration appears when electromagnetic radial force is applied onto the rotational rotor, which causes continual changes of airgap and further radical electromagnetic force. Nonlinear vibration of the rotor under the interaction of electromagnetic radial force and displacement becomes very complicated, which is becoming a research hotspot at present. A whole lateral vibration dynamics equation is established by finite element method. The radical force formula of single rotor tooth was deduced by integration of equivalent electromagnetic circuit and Maxwell stress method, and final functional expression of radial electromagnetic resultant when stator windings are energized with ideal square wave is also obtained. The critical speeds and vibration modes of the rotor are analyzed by Campbell diagram and lateral vibration displacement locus is solved by Newmark-Beta numerical integration method. The results show that the vibration locus of the rotor distributes in a circular domain. The frequency distribution of electromagnetic resultant relates to rotation speed, current switch frequency, and current wave, while the frequency distribution of the displacement also closely relates to the first-order critical speed of the rotor. When the rotor runs at some specific speed, lateral superharmonic resonance phenomenon appears and its displacement locus shows rich diversity. Lateral vibration characteristic of the rotor could be quickly grasped through this study, which makes vibration evaluation possible for advanced motor design.