To take single-phase PWM rectifier as AFE of cascaded H-bridge multi-level frequency converter can satisfy requirement that electric drive system of coal mine hoist must have capacity of bidirectional energy flowing. but there are third harmonic in its AC-side current because of the second ripple of output voltage. To slove the problem. a method of steady-state error feed-forward comp... https://www.roneverhart.com/BJORK-VULNICURA-2LP-Deluxe-Edition/