Partial Power Assistance Operation for Single-Phase Grid-Fed Motor Drive System with DC-Link Shunt Compensator

This paper proposes a partial power assistance operation to encourage the feasibility of a single-phase diode rectifier-fed motor drive system equipping DC-link shunt compensator (DSC). DSC which is located to DC-link in parallel allows to remove electrolytic capacitor and grid filter inductor from the system by performing grid current shaping and motor output power supporting controls. The capability of DSC is mainly determined by the required energy during grid disconnection time where DSC should fully supply motor output power. If motor drive system needs full-rated power in overall area, DSC should possess supply ability and becomes heavy and bulky. Moreover, since available DC-link voltage is relatively low during this area, total system efficiency is decreased. Therefore this paper proposes partial power assistance operating method for DSC system which can ease the burden of DSC. This method uses ripple power control in order to actively utilize the fluctuating DC-link voltage which is unique characteristic of the DSC system, so it is able to be applied ripple allowable applications. However the DSC system with proposed method has advantage for improving system efficiency and being able to miniaturize the DSC.