Active Buck-boost inverter with coupled inductors

Abstract

Due to the duty cycle restriction, the boost ratio of the conventional Boost converter is limited. In order to get a constant output voltage, the input voltage cannot be too low. This paper presents an active Buck-Boost inverter with coupled inductors. The operation modes, voltage stress of the switches and the voltage gain of the circuit is analyzed. By properly setting the turns ratio of the coupled inductors, the inverter can generate AC voltage whose peak value is much higher than the input voltage. When the input voltage is very high, the inverter can work in buck mode to get a constant output voltage. The voltage gain of the Boost AC/AC part based on coupled inductors can be constant if the duty ratio is corrected timely. Simulation and experimental results are presented to verify the proposed inverter can achieve buck-boost inversion with wide range of input voltage.