Performance analysis of a four switch 3-phase inverter fed IM drives

This paper investigates the performance of a 4-switch, 3-phase inverter (4S3P) fed cost effective induction motor (IM) drive system for high performance industrial drive systems. In the proposed approach, instead of a conventional 6-switch, 3-phase inverter (6S3P) a 4-switch, 3-phase inverter is utilized. This reduces the cost of the inverter, the switching losses, and the complexity of the control algorithms and interface circuits to generate 6 PWM logic signals. Furthermore, the proposed control approach reduces the computation for real-time implementation. The complete vector control scheme for the IM drive fed from the proposed 4S3P inverter is implemented in real-time using digital signal processor (DSP) T1 TMS320C31 for a prototype 1 hp motor. Theoretical and experimental results of the proposed drive verify the robustness of the drive. A performance comparison of the proposed 4S3P inverter fed drive with a conventional 6S3P inverter fed drive is also made in terms of speed response and total harmonic distortion (THD) of the stator current. The proposed inverter fed IM drive is found acceptable considering its cost reduction and other advantageous features.