Fast Current Control of the Single-phase DC-AC Converter Using Digital Peak Current Mode Control

Abstract

Peak current mode controlled converters can be made in a small size because it has fast response to suppress overshoot current, which can decrease the maximum rated current of various components such as a grid interconnected reactor, switching devices, etc. This paper presents a digital peak current mode controlled single-phase DC-AC converter with a new current control method which can reduce harmonic distortion of output current. This converter is mainly composed of a half-bridge at DC input side, full- bridge at AC output side and a reactor which is connected to the two bridges. The new current control method can estimate and compensate the drop of reactor current which is caused by current ripple and slope compensation. We performed experiments using a prototype converter rated at 3.3kW. The results showed that the proposed method could reduce the harmonic distortion of the output current. Furthermore, the effectiveness for suppression of overshoot current caused by disturbance of the AC grid voltage is also verified.