Analysis of Five Leg Voltage Source Inverter Fed Dual Motor Drive System

Abstract

With the advent of electric vehicle multi-machine drives are attaining overwhelming responses from the researchers and industries in recent years, as compared to their counterpart of single machine drive. In this regard, the industries are looking for multi motor control with single inverter system with precise speed control. The solution of aforesaid problem lies with multi-leg inverter fed dual induction motor drives that are capable for high power ratings and other specific applications. Any faults in the system leads to the failure of the operation of the entire drive system. Hence condition monitoring of the entire drive system becomes of paramount significance. Considering the aforementioned points, this paper focuses on the fault analysis of five leg voltage source inverter feeding dual induction motors. The drive system is simulated using MATLAB/ SIMULINK for different pulse width modulation techniques like SPWM, SVPWM and Two Arm Modulation (TAM) Techniques. The effect on fault in the inverter like opening of the switch and shorting the switch, on the performance of the induction motors are analysed. Total Harmonic Distortion (THD) of the stator current for different modulation techniques are compared for the analysis purpose. From the results it is observed that the THD is less for SVPWM techniques as compared with SPWM and TAM method. But independent control of both the machine cannot be attained by SPWM and SVPWM method. For independent speed control TAM method is used. So a trade-off has to be done considering the requirement and THD. It is finally concluded that independent speed control is achieved at the cost of higher THD.