Single-phase Power Conditioner with a Buck-boost-type Power Decoupling Circuit

This paper presents a novel single-phase inverter equipped with a buck-boost-type power decoupling function that is suitable for PV generation. The proposed buck-boost-type power decoupling circuit relaxes the increase of the DC-bus voltage of the PWM inverter compared with the conventional boost-type power decoupling circuit. This prevents the increase in switching and conduction losses caused by the high voltage rating switching devices. Another feature of the proposed inverter is a power decoupling control method based on a single-phase p-q theory. Because the proposed power decoupling method reduces the low-frequency ripple current flowing at the DC input, the electrolytic DC-bus capacitor is replaced by a small film capacitor that has a longer lifetime. The effectiveness of the proposed system is verified through simulation and experiments using a 200W experimental setup.