(A) new current source inverter for induction motor drive

Abstract

A new six-step current source inverter (CSI) with novel features of DC-side commutation and energy recovery (ER) are proposed with detailed analysis and explanation of the circuit operation. The proposed inverter operates over very wide range of frequency and load variation by employing the DC-side commutation. The commutation capacitance value and the power rating of the ER transformer are calculated. The energy recovery scheme has made the use of low voltage thyristors possible and contributed to an increase in inverter efficiency and reliability. And a control scheme without using tachometer is adopted for speed control. In this scheme, only the stator voltage of the induction motor is controlled for the constant flux operation. In the end, experimental results are given.