High frequency quasi-resonant DC voltage notching inverter for AC motor drives

A high-frequency quasi-resonant DC voltage notching inverter derived from a resonant DC link inverter is discussed. The quasi-resonant link circuit provides a DC voltage with resonant notches to the inverter such that inverter switches can switch at zero voltage crossing. Compared to resonant DC link inverters, the size of passive components is reduced. Compared to traditional pulse-width modulation (PWM) inverters, the efficiency and performance are largely improved because high-frequency switching occurs at zero voltage crossing. The resonant voltage notches can be created at any instant, which permits the inverter to operate at standard or optimized PWM control. A least current error square method is proposed to incorporate the quasi-resonant DC voltage notching inverter, resulting in minimum output current ripples. For regenerative-type AC drive operation, a bidirectional current initialization is included in the circuit. The complete system was simulated using PC-SIMNON and fabricated as a laboratory prototype.<>