Zero-Speed Operation of High-Power PWM Current-Source-Inverter-Fed Induction Motor Drive

Most research work in current-source inverter (CSI) fed motor drives has focused on general control strategies, pulsewidth modulation schemes, topologies, and efficiency evaluation. This paper, however, is dedicated to investigating zero-speed operation characteristics of CSI-fed induction motor drives (IMDs). Zero-speed operation can greatly increase the competitive value of the drive and expand its range of applications to include cranes, hoists, and draglines. The motor drive is controlled with rotor flux orientation, where stator currents and motor speed are employed for the rotor flux estimation. Unlike voltage-source-inverter-based drives, filter capacitors are required at the output of the CSI for current commutation and harmonics filtering. The influence of these capacitors on the system dynamic performance is comprehensively evaluated. Moreover, a classic load torque observer with feedforward control is employed to improve the speed dynamic response. Simulated and experimental results show that the CSI-fed IMD works well at zero speed with promising speed dynamic performance.