Investigation of harmonics interaction in high-power PWM current-source motor drives

For high-power current-source drive systems, due to the limited dc choke size and low converter switching frequency, the distortion of dc-link current cannot be ignored. The distorted dc-link current will introduce interharmonics in the grid side and the motor side through the rectifier and the inverter, and may give rise to the system resonance at certain motor speeds. In this paper, the harmonics interaction in highpower PWM current-source drive systems is investigated, and a method for the system resonance estimation is proposed. The investigation and proposed resonance estimation method is verified through both simulations and experiments.