Wen Ding

Dynamic Modeling and Performance Prediction for Dual-Channel Switched Reluctance Machine Considering Mutual Coupling

Switched reluctance machines (SRMs) are normally designed and applied as 6/4 or 8/6 single-channel SRMs. However, recent efforts with 12/8 dual-channel SRMs (DCSRMs) have spurred interest. The 12/8 DCSRM is driven by two independent sets of power electronic circuits with dual control channels, and the two channels would have strong interactions between each other due to the magnetic mutual coupling for each channel. We propose a dynamic modeling strategy that accounts for the effect of mutual coupling of a DCSRM. First, we illustrate the flux patterns of a DCSRM under different operation modes. Then, we use an indirect experimental procedure to measure the static self and mutual flux linkages for the DCSRM. By using the measured flux linkage data, we describe a simulation model for a DCSRM operating in single-channel mode and dual-channel mode in which the mutual coupling is considered. We predict and compare the dynamic performance characteristics such as phase currents, flux linkages, energy conversion, and static torque under different operation modes and excitation conditions. Finally, we compare the simulation and experimental results for four operating conditions in DCSRM systems in single-channel mode and dual-channel mode. The proposed modeling strategy for the DCSRM is quite accurate.

Modeling of a 6/4 Switched Reluctance Motor Using Adaptive Neural Fuzzy Inference System

The magnetic saturation and strong nonlinearity of switched reluctance machines (SRMs) makes it very difficult to derive a comprehensive mathematical model for the behavior of the machine. We propose a new method of modeling SRMs based on an adaptive neural fuzzy inference system (ANFIS). First, we use an indirect method to measure the static flux linkage and then use the co-energy method (via the principle of virtual displacement) to calculate the torque characteristics from data on flux linkage versus current and rotor position. A hybrid learning algorithm, which combines the back propagation algorithm and the linear least-squares estimation algorithm, identifies the parameters of the ANFIS. After training, the ANFIS flux linkage model and ANFIS torque model are in excellent agreement with experimental flux linkage measurements and the calculated torque data. Finally, we use an ANFIS current model and an ANFIS torque model to study SRM dynamic performance. The accuracy of the model was evaluated by comparison to laboratory measurements of the machines current-speed and torque-speed characteristics. The model is quite accurate.

Comparative Studies on Mutually Coupled Dual-Channel Switched Reluctance Machines With Different Winding Connections

This paper presents comparative studies of magnetic characteristics and dynamic performances for two mutually coupled dual-channel switched reluctance machines (DCSRMs) with the same properties and different winding connections. A 2D/3D finite element method (FEM) is used to analyze the magnetic field distributions and calculate the static inductance and torque characteristics of these two DCSRMs. The different static magnetic characteristics, details of mathematical models and dynamic performances prediction at transient and steady states for these two DCSRMs under single- and dual-channel operation modes are presented and compared. Finally, an experimental setup for two high speed 12/8-pole DCSRMs with different winding connections is built. The experimental results of these two DCSRMs such as phase current, average torque, copper loss, iron loss and efficiency under different operation modes are presented and compared to verify the analytical and simulation results.

Investigation and Experimental Test of Fault-Tolerant Operation of a Mutually Coupled Dual Three-Phase SRM Drive Under Faulty Conditions

The mutually coupled dual three-phase switched reluctance motor (DTPSRM) is a new type of special 12/8 SRMs, which possesses high-reliability and fault-tolerant feature. In the past researches, the model, analysis, and fault-tolerant operation were mainly focused on the classical single three- and four-phase SRMs. This paper is mainly to analyze and investigate the fault-tolerant performances of a 12/8-pole mutually coupled DTPSRM drive under various open-circuit operations. First, the static magnetic characteristics of DTPSRM with single- and two-phase excitations are calculated by finite-element analysis. Then, the mathematic model of the DTPSRM drive under open-circuit condition is developed with a combination of state and fault functions. The simulation model of the DTPSRM drive system with a fault-tolerant control strategy is established for dynamic analysis. The faulty characteristics and fault-tolerant performances of the DTPSRM with diverse open circuits are predicted. Finally, a 12/8 DTPSRM is prototyped and an experimental setup is built for verification. The experimental normal results and diverse open-circuit operations and self-starting capability under lack of phases are presented, validating the accuracy of the analysis and simulation as well as fault-tolerant characteristics of the DTPSRM drive system.

Comprehensive Research of Modular E-Core Stator Hybrid-Flux Switched Reluctance Motors With Segmented and Nonsegmented Rotors

Modular switched reluctance motors (MSRMs) normally have better characteristics than conventional SRMs (CSRMs) such as lower cost, higher torque production, stronger fault-tolerance, less loss, etc. This paper comprehensively investigates two hybrid-flux MSRMs with the same E-core stator, but different rotor configurations, termed as segmented-rotor MSRM (SR-MSRM) and nonsegmented rotor MSRM (NSR-MSRM), as well as compares with a CSRM. To evaluate the effects of different rotor topologies, the electromagnetic performances of two MSRMs and a CSRM with the same basic dimensions, including machine cost, flux distribution, static flux linkage, and torque, dynamic and transient operation performances are comprehensively analyzed and compared. The results based on finite-element analysis and Simulink indicate that the SR-MSRM has lowest steel consumption, highest torque production, highest power and torque densities, and strongest starting capability. Finally, three motor prototypes, including one SR-MSRM, one NSR-MSRM, and one CSRM are manufactured. The experimental results of static magnetic characteristics, dynamic and transient performances of three SRM drives confirm the predictions.

Novel nonsingular fast terminal sliding mode control for a PMSM chaotic system with extended state observer and tracking differentiator

A novel nonsingular fast terminal sliding mode (NNFTSM) control strategy based on the extended state observer (ESO) and the tracking differentiator (TD) is developed for the stabilization and tracking of the uncertain perturbed permanent magnet synchronous motor (PMSM) chaotic system. The proposed NNFTSM surface not only makes the system state rapidly converge to the equilibrium point in finite time with high steady-state precision, but also avoids the singular phenomenon. Furthermore, the ESO which does not rely on the mathematical model of the system is used for estimating uncertainties and disturbances to decrease the chattering caused by the big switching gain through compensating controller. Meanwhile, the TD is introduced to arrange the transition process for the reference input signal to realize the coordinated control between the rapidity and overshoot, and to decrease the initial impulse of the manipulative variable. The simulation results demonstrate that the proposed control scheme can flexibly restrain chaos which provides good dynamic and static performances, and has strong robustness to parameter variations and external load disturbances with low chattering.

Design Consideration and Evaluation of a 12/8 High-Torque Modular-Stator Hybrid Excitation Switched Reluctance Machine for EV Applications

This paper presents a 12/8-pole, three-phase, modular-stator hybrid excitation switched reluctance machine (MSHSRM) assisted with permanent magnets (PMs) as well as its design consideration and performance evaluation. The basic operating principle is illustrated through a specific form of this machine, and the magnetic equivalent circuit model is built and analyzed. Then, the main parameters of the machine are optimized by the finite-element method. The static magnetic characteristics and dynamic performance of this novel machine are simulated and compared with other two SRMs, one is segmented 12/8 SRM without PM, and the other is the conventional 12/8 SRM with unsegmented structure. Finally, two motor prototypes, including one MSHSRM and one conventional SRM of the same size are manufactured. The static magnetic characteristic and dynamic operation of two motor drives are measured to confirm the predictions. The simulation and experimental results indicate that this MSHSRM has higher power and stronger load capacities than the conventional SRM in whole speed range with higher torque/power density and higher torque per ampere.

Characteristics comparison of conventional and modular E-core stator with segmental rotor switched reluctance motors

This paper presents comparative studies between a novel modular switched reluctance machine (SRM) with modular E-core stators and segmental rotors and a conventional SRM. Owing to the particular construction, there are hybrid magnetic paths with both radial and axial magnetic paths in the modular E-core stators SRM. To evaluate the motor performance, a 3D modeling finite-element analysis (FEA) is presented to simulate its flux distribution. Comparisons of static magnetic characteristic and dynamic performance between the modular SRM and the conventional 6/4 SRM are made to emphasize and evaluate the advantages of this novel SRM. Finally, a prototype modular SRM is built and tested in the laboratory. The measured static flux linkage characteristic and dynamic operation of the MSRM are presented to verify the theoretical and simulation results.

Analysis and experimental verification of fault-tolerant performance of a mutually coupled dual-channel SRM drive under open-circuits

The mutually coupled dual-channel switched reluctance machine (DCSRM) is a kind of special machine, which inherently offers high fault-tolerant feature. The purpose of this paper is to analyze and investigate the fault-tolerant performance of the DCSRM at open-circuits. Firstly, the faulty mathematic model of the DCSRM under open-circuit fault is developed with combination of a state and a fault functions. The simulation model of the DCSRM drive based on Matlab/simulink is established for dynamic analysis. To achieve fault-tolerant operation, a speed closed-loop control is performed to maintain the speed as the normal operation. The dynamic performances of the DCSRM under normal and open-circuit faults are predicted. Finally, an experimental setup for a 12/8 DCSRM drive is built for verification. The experimental results at normal, various open-circuit faults and sudden changes of load torque operations are presented to verify the analytical and simulation results and fault-tolerant control strategy of the DCSRM drive system.

Development and Investigation on Segmented-Stator Hybrid-Excitation Switched Reluctance Machines With Different Rotor Pole Numbers

In order to improve the performances of switched reluctance machines (SRMs), such as torque production and power density, combining segmented structure and hybrid-excitation is a proper and useful method. This paper develops a kind of segmented-stator hybrid-excitation SRMs (SS-HESRMs) assisted with permanent magnets (PMs) and investigates on them with different rotor pole numbers. To evaluate the effects of different rotor topologies, the static magnetic characteristics and dynamic performances of two SS-HESRMs with 12/10 and 12/8 poles are briefly presented. Moreover, both SS-HESRMs are compared with two segmented-stator SRMs (SS-SRMs) which have the same basic structure and stator/rotor pole combinations but without PMs. The results reveal that SS-HESRMs produce higher electromagnetic torque than SS-SRMs with the same stator/rotor pole configuration. The 12/10 SS-HESRM exhibits better characteristics, such as higher dynamic average torque, lower torque ripple, and higher power/torque density, than the 12/8 SS-HESRM at low-speed operation. While at high speed, the 12/8 SS-HESRM exhibits better characteristics than 12/10 SS-HESRM. The 12/10 SS-HESRM has stronger starting capability but lower steady-state speed under the same starting condition. Finally, a 12/10 SS-HESRM and a 12/8 SS-HESRM with the same structure and size are prototyped and tested to confirm the predictions.