Output Current Regulation with PWM Inverter--Induction Motor Drives

Current regulation plays an important part in the protection of solid-state drives operating from stiff voltage sources. Certain types of pulsewidth modulated (PWM) inverters, however, are not directly suited for peak or average output current regulation with induction motor loading. It is established in the paper that the typical output voltage response times of defined voltage waveform PWM inverters are 1) too high for peak output current regulation, and 2) too low for average output current regulation---i.e., for stable current regulation, the control system must limit the rate of inverter output voltage reduction. Inverter voltage control requirements and inverter deratings necessary to implement average output current regulation are presented. Experimental results from a 15-hp bread-board are included.