High-efficient low-noise soft switching inverter with two-level PWM resonant snubber for telecommunication energy utilization

This paper proposes a novel quasi-resonant DC link circuit with voltage clamped PWM scheme and deals with a three-phase space voltage vector modulated sinewave soft-switching inverter incorporating a single auxiliary resonant DC link snubber into its DC voltage bus line. This two level PWM resonant DC link circuit capable of adjusting DC line bus voltage-clamped PWM and zero voltage holding PWM period in DC bus line can realize the soft-switched chopper operation under the principle of soft-switching. Its operating circuit analysis in repetitive steady-state is performed. This type of soft-switching inverter using two level PWM resonant DC link which includes an optimum type digital voltage servo controller in the d-q coordinate frame is presented and its new pulse pattern sinewave space vector modulation is demonstrated in order to minimize the switching losses and conduction losses. It is proved that this inverter topology is more effective to reduce the switching losses as well as the conduction losses of the active power switches (IGBTs) with three-phase bridge arms and resonant DC link snubber.