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

Abstract

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.

Introduction

In the recent past, the research in the Switched Reluctance Motor (SRM) plays a key measure to find an alternative to the Induction Motor (IM) drive in the industrial applications as well as in the variable speed drive market. The SRM has numerous advantages over the IM and Permanent Magnet Brush Less DC (PMBLDC) motor due to its minimal maintenance, wide speed range, and operates in high temperature environment [1]. The adjustable speed of single phase IM drive with reduced number of switches requires frequent maintenance and faces power quality issues is explained in [2]. The scholars has chosen SRM with integration of charging capacity for hybrid electric vehicle to reducing CO₂ emission in the atmosphere [3], and numerical analysis experiment in the invention of new double layer SRM drive system [4].

The drawbacks of SRM drive in the hybrid electric vehicles are noise and vibration produced by the motor. The prediction of noise and control measures and vibration control of switched reluctance motor are discussed in [5,6]. The torque ripple production, acoustic noise and vibration of motor during operation are prime causes to discard of the SR motor in the industrial areas. The torque ripple production makes fast switching in the excitation of phase windings and forced commutation thus fault occurs in the motor.

To mitigate, the torque ripple content at the output, the new methods are proposed in the paper [6], [7], [8]. The power converters play a vital role in the SRM operation, the new topologies are proposed to nullify the drawbacks in [9], [10], [11]. The conventional controller and vector control techniques are used to control SRM in [12,13]. The advanced controller designs and techniques such as Fuzzy Logic Controller (FLC), open loop control, Artificial Neural Network (ANN) controllersare introduced to control the motor drive in [14]. The electromagnetic energy efficient conversion of SRM motor is presented in [15].

The fault existence possibilities in SRM drives are more than the other drives. Because the SR drives operation consists of high number of stages from input supply to the output. The fault detection methods using K-means clustering algorithm that are explained in [16]. A new method to diagnosis the power converter faults and flexible fault tolerance topologies are proposed to diagnosis the fault occurrence in the system are discussed in [17,18] respectively. The other fault investigation methods using rotor structure [19], inter turn faults diagnosis using Space Vector Modulation (SVM) technique [20], fault tolerance analysis of SRM with distributed inverter [21] are presented. In this work, Wavelet Transforms (WT) based, fault analysis method is implemented to find the various faults in the SRM drive. The various faults in the SRM drive are illustrated, in the Fig. 1. The proposed converter with WT based fault identification method is realized using MATLAB simulink tool and the same is validated through experimental results.