A high efficiency high frequency resonant inverter for high frequency ac power distribution architectures

Abstract

A high efficiency two-stage resonant inverter with effective control of both the magnitude and phase angle of the output voltage was proposed in this paper for high frequency AC (HFAC) power distribution applications, where a number of resonant inverters need to be paralleled. In order to parallel multiple resonant inverters of the same operation frequency, each inverter module need independent control of the phase angle and magnitude. It is also desirable that the output voltage has very low total harmonics distortion, as well as high efficiency over wide input and load ranges. The proposed resonant inverter consists of two stages. The first stage is a two-switch DC/DC converter with zero voltage transition, and the second stage is a half-bridge resonant DC/AC inverter with fixed duty ratio. A series-parallel resonant tank is used to achieve high waveform quality of the output voltage. The output voltage of the inverter can be regulated through the pulse width modulation of the duty ratio of the first stage. The phase angle of the resonant inverter can be regulated through a pulse phase modulation control of the second stage. The proposed resonant inverter has the advantages of better waveform quality, and wide range of input and load variations for soft-switching, independent control of the phase angle and magnitude, making it an attractive selection for applications where a number of resonant inverters need to be placed between the DC bus and HFAC bus, and a number of distributed loads are connected to the HFAC bus. The performance is verified with both simulation and experiments.