Ultra-High Speed Switched Reluctance Motor-Generator for Turbocharger Applications

The objective of this study is to create an ideal model for an ultra-high speed switched reluctance motor generator for automotive turbocharger assistance and energy recovery by using electromagnetic finite element analysis. For this purpose, the transient simulation process is considered. The modelling and analysis of a switched reluctance motor (SRM) is the initial task for the selection of the coupled mover. The SRM must be able to achieve high speed and enough starting torque to actuate the coupled compressor and turbine, for the application of an automotive turbocharger. With the use of finite element analysis, a motor was designed to achieve the performance requirements of turbocharger coupling.

This paper presents detailed analysis, and operation of Asymmetric Half Bridge (AHB) converter topology and shared switch converter topology for 4-phase Switched Reluctance Motor (SRM) drives. Compared to an asymmetric half bridge converter, shared switch converter reduces the number of switches and diodes. Simulation results show that both topologies give the same results of phases flux, phases current, torque electric, and speed. However, some switches in shared switch converter controlled more than one phase. So, the number of switching at operation speed condition is twice more than other switches on asymmetric half bridge or shared switch converter. The simulation results are made by MATLAB/SIMULINK.

A switched reluctance motor (SRM) is well suited to the electric propulsion of a hybrid electric vehicle (HEV), due to its simple and rugged construction, low cost, and ability to operate over a wide speed range at constant power. This paper presents the design optimisation of SRMs for HEV applications, by using a combination of 2D electromagnetic finite element (FE) analysis, experience from previous designs, 3D correction factors, simple lumped-parameter thermal models, and computer search techniques. A prototype SRM was built and fully tested. The experimental results validate the design methodology. Based on the optimal lamination profile of the prototype, five motors were constructed for two HEVs: two for a parallel HEV and three for a series HEV. The two cars have demonstrated excellent performance with the optimised SRMs.

A Permanent Magnet Reluctance Generator (PMRG) possesses important features such as simplicity and low cost. Absence of rotor winding allows the generator to run in a wide speed range. The PMRG may have potential to be used in wind power conversion systems. An asymmetric half bridge (AHB) converter may be acceptable as a classical converter topology for PMRGs and offers independent phase control. The AHB converter with a torque ripple minimization-assisted maximum power point tracking algorithm not only provides significant torque ripple reduction on the mechanical side but also allows conversion of maximum wind energy to electrical energy. The major drawback is that the AHB converter is not commercially available as a single module; hence, manual construction by combining discrete components is required. Instead, this work introduces for the first time, the use of a full bridge (FB) converter for independent phase control of the PMRG. The main advantage is that the FB converter is commercially available as a standard intelligent power module. In order to obtain unidirectional current as in the AHB converter, modified delta configuration of the phase windings has been used. The experimental results under fixed and variable wind speed conditions confirm the effectiveness of the proposed control-converter configuration.

A Switched Reluctance Motor (SRM) is often characterized with structural simplicity and low cost. However, its torque density and efficiency is generally lower than any same size AC machine. In this research, performance improvement in the SRM has been investigated under the presence of low-cost permanent magnets (PMs). The Permanent Magnet Switched Reluctance Motor (PM-SRM) is formed by burying PMs on stator yoke. A non-rare earth type magnet, Alnico, has been employed for this purpose. Alnico magnets in AC machines is limited because of low coercivity against reverse magnetic field. However, this is not an important issue for PM-SRM driven by an Asymmetric Half Bridge Converter. The analysis results of PM-SRM demonstrate that a significant increase in efficiency, torque density as well as in power factor can be obtained without losing much from the low-cost feature.

In this paper, A 12/8, 3-phase, 28 A, 1.25 kW, SRM (Switched Reluctance Motor) is controlled for the application of LEV (Light Electric Vehicle). Asymmetric half-bridge (ASHB) converter is implemented to drive the SRM with a lead-acid battery connected across the DC-link capacitor. An MPC (Model Predictive Control) based sensorless approach is implemented on the target SRM. The estimation of rotor position is executed with the help of the flux-current-position characteristics obtained from the characterization of the machine. The rotor speed is estimated from the instants, as the rotor passes from certain discrete positions and from the estimated rotor speed, the position is estimated and fed to the MPC controller for the switching. The rotor position, phase current and torque are predicted from the analytic and look-up table based models. The cost function is formulated for the torque control of the SRM. The phase current is kept in the limit with two stage cascaded controller, in this work. The regenerative braking feature is added to system, in which a part of energy (kinetic) stored in the moving part of the system is fed back to the input source and thus the range of EV is enhanced in case of practical system.

This paper presents a highly integrated converter topology in plug-in electric vehicle (PEV) switched reluctance motor (SRM) drive system, which can also achieve battery charging function and vehicle-to-grid (V2G) function. This integrated converter can implement three operation modes. In the driving mode, the SRM works as a normal four-phase motor, every phase is connected an asymmetrical half-bridge structure. In the charging mode, the SRM phase windings are used as large inductance, among two phases are directly connected to the grid. So, the two phases asymmetrical half-bridge are rebuilt a bridgeless power factor correction (PFC) converter to satisfy the power quality requirement. Another phase asymmetrical half-bridge is constructed to be a buck-boost convertor to realize battery charging. In the V2G mode, the two phases asymmetrical half-bridge and a large capacitance are used as a voltage source type inverter(VSTI), which can feedback the capacitance power to the grid. The other phase can run as a boost converter to boost up the dc-link voltage from battery. This highly integrated technology will play an important role in miniaturization and efficiency of electric vehicles.

This paper investigate a 12/10-pole Switched Reluctance Motor (SRM) which can be used as a six-phase or three-phase machine by altering the winding connection. The parameter relationship including resistance, inductance, phase current and torque between two operation modes is deduced and analyzed. A connection method between the machine and power converter based on three-phase asymmetrical half bridge (AHB) structure and the corresponding control strategy are proposed to carry out dual-mode operation. The inductance and torque characteristics of six-phase and three-phase operation are comparatively analyzed, and then the steady-state performances and mode-changing simulation are also performed. Finally, an experimental setup is developed and the independent steady-state operation and mode-changing experiment are implemented. Both the simulations and experiments validate the proposed mode-changing scheme.

Signal Generation for Switched Reluctance Motors using Parallel Genetic Algorithms

Based on theoretical derivation, the rotor structure of a 2-phase 4/2 switched reluctance motor (SRM) for high-speed application is optimized in this paper. In light of the proposed method, a rotor with asymmetrical air-gap is designed to improve the disability of self-start and torque ripple by broadening the positive torque region, based on which a prototype SRM running up to 30000 r/min is manufactured. For the drive topology, an active front-end rectifier controlled by model predictive direct power control (MP-DPC) algorithm is proposed to provide a stable DC-link voltage for the asymmetric half-bridge (AHB) converter. Compared with the conventional diode bridge rectifier, the active front-end rectifier can significantly increase the grid-side power factor by directly manipulating the reactive power flow in the rectifier. An idea-proofed testbench is constructed to verify the feasibility of the proposed drive topology based on the optimized 4/2 high-speed SRM.

Traditionally, an uncontrollable diode bridge rectifier (DBR) is employed to supply the constant DC voltage for the asymmetric half-bridge (ASHB) converter fed switched reluctance motors (SRMs), which brings about inferior AC side power quality. In this article, a high-speed SRM drive system based on integrated power control scheme is proposed, which not only realizes the regulation of SRM but improves the AC side power quality. For the topology, a single-phase H-bridge rectifier and ASHB converter are connected in a cascade arrangement to form an AC-DC-DC converter to drive the SRM. For the control, the proposed integrated power control scheme governs the rectifier and SRM as one control unit in which stable motor speed and high AC side power factor are realized via regulating the input real and reactive power, respectively. Moreover, the proposed system has bi-directional power flow capability, which means the power can flow out of and into the AC side. Experiments are carried out to investigate the steady-state and dynamic performances of the proposed driving system. The experimental data and performance comparison confirm its effectiveness.

The popularity of the Switched Reluctance Motors (SRMs) increases gradually due to its advantages such as low weight, less cost, high efficiency, high starting torque and rugged construction as compared to conventional motors. The overall cost reduction of SRM drive can be done with minimum switching devices in power converter. The ac split supply converter is best alternative for asymmetric bridge converter. This paper deals with the performance of ac split converter and asymmetric bridge converter with 8/6 SRM motor using MATLAB simulation. The 8/6 SRM motor parameter is determined with Ansys / Rmxprt. This paper discusses split ac supply converter has low cost and better efficiency.

This paper introduces a variable magnet switched reluctance motor (VM‐SRM) drive that can be characterized with adjustable performance. It consists of a switched reluctance (SR) motor with low coercive force (LCF) magnets buried on stator yoke and a modified asymmetric half bridge (AHB) converter. Magnetization level of the LCF magnets is adjusted by injecting a current pulse to a phase winding of the VM‐SRM. The magnetization process does not need any extra coil and provides a simplicity owing to modified AHM converter. Possible magnetic saturation that limits the magnetization level is overcome by injecting current pulses to two phase windings at the same time. Thus, LCF magnets can be used with their full capacity. The presented analysis results demonstrate that proposed VM‐SRM drive provides a variable performance and might be a candidate for future variable speed applications. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

A switched reluctance motor (SRM) has been developed with merits such as the low cost and reliability. Recently, its application has been expanded from industrial to home appliance use. The inverter of the SRM is more robust than that of induction or brushless DC(BLDC) motors, but still its drive is comparatively expensive for home appliances. To drive a conventional three- or four-phase SRM, 6 to 8 power switches are required when an asymmetric bridge inverter is employed. Generally, more than 50% of the cost for the SRM drive is allocated to power devices and gate drives. This paper proposes a single-phase SRM that has both radial and axial air gaps. The stator and rotor were stacked with two types of stampings that have different diameters. This configuration is very effective to increase align inductance (Lmax). The high value of Lmax increases the motor efficiency and power density. The proposed single-phase SRM (Claw SRM) can be driven by only two power switches. To show the validity of the proposed idea, an analysis using the finite element method (FEM) and experimental works are carried out. The proposed SPSRM can be driven with high efficiency and can be made compactly and inexpensively because of the high value of align inductance and reduced number of switches. For the comparison, the authors used the same stator for three-phase and single-phase designs, and slightly different stators and rotors for the proposed single-phase SRM (Claw SRM).

A multilevel converter topology for switched reluctance motor (SRM) drive with integration of front end circuit is appealing for electric vehicle. As SRM carries the highlights like simple construction, high reliability, high fault tolerance capability and low production cost. However, the high torque ripples, running vibrations and acoustic noise are the major drawbacks in SRM. In proposed theory of a multilevel converter for five phase SRM drive overcome this drawbacks and flip it into advantages like high torque range, low torque ripple and vibration free response with flexible speed control. This paper represents a operating theory and simulation results of five phase muliltlevel converter for SRM drive. Which results, with increasing the number of phases the system performance is increase without increasing the number of switching devices and a comparison is shown based on torque speed characteristics of motor when fed from proposed converter and a asymmetric half bridge converter for different condition. This analysis states the proposed converter topology is advantages over the conventional converter topology, especially for the high speed response.