A low-profile, high power density Inverter with minimal energy storage requirement for ripple cancellation

An inherent characteristic of a Single-Phase Inverter is the DC-link voltage ripple. In order to ensure Maximum Power Point Tracking (MPPT) in Photovoltaic (PV) systems, the voltage ripple needs to be suppressed through use of an energy buffering device which can be a passive, i.e. typically a capacitor or active in the form of an Active Power Filter (APF). This paper describes a novel approach to an APF through a combination of hardware and software advances, with an emphasis on: a) further efficiency improvements through enhanced control; b) maximized deployment capabilities - the proposed APF is independent of the Inverter and can directly replace the DC-link ripple capacitor; c) high quality ripple cancellation; d) minimum storage capacitance.