This paper presents a STATCOM with a self-oscillating bidirectional dc-dc converter for interfacing battery energy storage in a stand-alone induction generator system. The self-oscillation mode is based on relay feedback control with hysteresis. To reduce the output current ripple, an LCL filter is connected between the half bridge of this dc-dc converter and the energy storage system. The other side of bidirectional converter is coupled with a voltage-source converter. The proposed control allows that the previous electronic converters, with an additional resistive dump load, compensate all disturbances in a self-excited induction generator due to three-phase four-wire loads and an improvement of system efficiency. The simulated results show good performance of the stand-alone power system under different loading conditions.