An integrated switched reluctance motor drive topology with voltage-boosting and on-board charging capabilities for plug-in hybrid electric vehicles (PHEVs)

This paper presents a new topology of switched reluctance motor (SRM) drive for plug-in hybrid electric vehicles (PHEVs). Six operating modes can be achieved as a result. Three of those modes are applied for driving and the others for charging. During the driving mode, the topology can be converted to a four-level one. During the charging mode, two battery packs are charged in parallel with the boost circuit by the external AC source or generators. The main contributions of the proposed topology are as follows: 1) A four-level converter is formed by adopting different ways of connection (series or parallel) of the two battery packs (or the two capacitors), which can accelerate the excitation and demagnetization procedures of SRMs. Moreover, the topology contributes to decreasing the switching losses and extending the constant torque region to improve the drive performance as well. 2) The state of charge (SOC) of the two battery packs (or the voltages of two capacitors) can keep balance on their own by parallel operation of the two battery packs. Furthermore, a detailed comparison between two drive modes of the proposed topology and asymmetric half bridge inverters is undertaken with simulation and experimental studies, the results of which demonstrate the validity of the proposed topology

A neutral-point diode-clamped converter with inherent voltage-boosting for a four-phase SRM drive

This paper proposes a new asymmetric neutral-point diode-clamped (NPC) multilevel converter for a four-phase switched reluctance motor drive. The inbuilt NPC clamping capacitors are used for both voltage level clamping and also as dc rail voltage-boosting capacitors to increase the output power of the motor, particularly for high-speed electric vehicle applications. The new converter allows regenerative energy to be recovered back to the dc supply for rapid machine braking, thus increasing overall drive efficiency. Analysis of the different modes of converter operation, along with design equations for sizing the voltage-boosting capacitors, are detailed. The effect of capacitance on boost voltage and increased motor base speed is presented. Simulation and experimental results confirm the effectiveness of the proposed converter

A Review of the Power Converter Interfaces for Switched Reluctance Machines

The use of power electronic converters is essential for the operation of Switched Reluctance Machines (SRMs). Many topologies and structures have been developed over the last years considering several specific applications for this kind of machine, improving the control strategies, performance range, fault-tolerant operation, among other aspects. Thus, due to the great importance of power electronic converters in such applications, this paper is focused on a detailed review of main structures and topologies for SRM drives. The proposed study is not limited to the classic two-level power converters topologies dedicated to the SRMs; it also presents a review about recent approaches, such as multilevel topologies and based on impedance source network. Moreover, this review is also focused on a new class of topologies associated to these machines, namely the ones with fault-tolerant capability. This new category of topologies has been a topic of research in recent years, being currently considered an area of great interest for future research work. An analysis, taking into consideration the main features of each structure and topology, was addressed in this review. A classification and comparison of the several structures and topologies for each kind of converter, considering modularity, boost capability, number of necessary switches and phases, integration in the machine design, control complexity, available voltage levels and fault-tolerant capability to different failure modes, is also presented. In this way, this review also includes a description of the presented solutions taking into consideration the reliability of the SRM drive.info:eu-repo/semantics/publishedVersio

PV generator-fed water pumping system based on a SRM with a multilevel fault-tolerant converter

This paper presents a pumping system supplied by a PV generator that is based on a switched reluctance machine (SRM). Water pumping systems are fundamental in many applications. Most of them can be used only during the day; therefore, they are highly recommended for use with PV generators. For the interface between the PV panels and the motor, a new multilevel converter is proposed. This converter is designed in order to ensure fault-tolerant capability for open switch faults. The converter is based on two three-level inverters, with some extra switches. Moreover, to reduce the number of switches, the converter is designed to provide inverse currents in the motor windings. Due to the characteristics of this motor, the inverse currents do not change the torque direction. In this way, it was possible to obtain an SRM drive with fault-tolerant capability for transistor faults; it is also a low-cost solution, due to the reduced number of switches and drives. These characteristics of fault-tolerant capability and low cost are important in applications such as water pumping systems supplied by PV generators. The proposed system was verified by several tests that were carried out by a simulation program. The experimental results, obtained from a laboratory prototype, are also presented, with the purpose of validating the simulation tests.info:eu-repo/semantics/publishedVersio

SRM power density improvement utilising rotor conducting screens and DC‐link voltage boosting for EV applications

The power density enhancement of a four-phase switched reluctance motor using rotor conducting screens and DC-link voltage boosting for electric vehicle applications is studied. The effect of conducting screen thickness and material electrical conductivity on current rise time, developed torque, and output power is studied. Different screen shapes are compared that elicit the optimum screen design by formulating a multi-objective optimisation problem based on maximising the developed torque and efficiency and minimising added material weight. A double arm common switch converter with a DC-link voltage-boosting capacitors is deployed. The boosted voltage provided by the capacitors aids the winding current to rapidly build-up; thus, increasing the motor base speed, whence power rating. Finite element analysis results confirm the SRM drive's effectiveness in increasing the motor base speed and improving the torque range; hence make the power capability of SRMs to be competitive with an equivalent volume permanent magnet synchronous motor

Fault-tolerant multilevel converter to feed a switched reluctance machine

The switched reluctance machine (SRM) is one of the most interesting machines, being adopted for many applications. However, this machine requires a power electronic converter that usually is the most fragile element of the system. Thus, in order to ensure high reliability for this system, it is fundamental to design a power electronic converter with fault-tolerant capability. In this context, a new solution is proposed to give this capability to the system. This converter was designed with the purpose to ensure fault-tolerant capability to two types of switch faults, namely open- and short-circuit. Moreover, apart from this feature, the proposed topology is characterized by a multilevel operation that allows improvement of the performance of the SRM, taking into consideration a wide speed range. Although the proposed solution is presented for an 8/6 SRM, it can be used for other configurations. The operation of the proposed topology will be described for the two modes, fault-tolerant and normal operation. Another aspect that is addressed in this paper is the proposal of fault detection and diagnosis method for this fault-tolerant inverter. It was specifically developed for a multilevel SRM drive. The theoretical assumptions will be verified through two different types of tests, firstly by simulation and secondly by experiments with a laboratory prototype.info:eu-repo/semantics/publishedVersio

Design of a Switched Reluctance Motor Controller Applied to Electric Vehicles Traction.

Switched reluctance motors (SRM) are a suitable and cheaper alternative for current electric vehicle (EV) powertrain topologies due to low weight, high torque/size ratio and simple construction, without permanent magnets and a minimum amount of copper. The main setback that these motors encounter is the high torque ripple, mainly due to the highly nonlinear torque generation mechanism. Torque ripple leads to mechanical vibrations that require unnecessary wear in the mechanical powertrain. In conventional torque sharing function (TSF) control, the torque produced by the machine cannot follow the expected torque for an extended speed range, mostly due to the imposed demagnetization of the outgoing phase at high speeds, resulting in poor performance and causing a high torque ripple. The main goal of this work is to design and validate a new SRM control method suitable for EV propulsion. The proposed controller applies a feedback loop that improves the weakness of the conventional methods, keeping a fast dynamic response. The simulation results show that torque ripple can effectively be reduced for a high torque and speed range. The researched algorithm is developed using Matlab/Simulink, basing the validation on experiments with a 60kW SRM, 12/8 poles prototype designed using finite element methods (FEM)