Abstract: A flywheel battery system is designed which is mainly composed of five parts: power converter in power side, excitation capacitor, power converter in machine side, switched reluctance machine integrated with a flywheel and the control system. In order to enhance the suitability of the system, a new DC-DC converter is used which can realize bi-directional power flow and boost-buck function in both directions at the same time. Meanwhile, a capacitance in the converter acts as the excitation power of SRM, so that the structure of the system is simplified. In the charging stage, current chopping method and angle position control is used to achieve control of the flywheel battery output power. In the Discharging stage, angle position control method combined with voltage chopper control method is used to realize control of output voltage and output power. A simulation model is set up by Matlab to verify the effectiveness of the energy storage/release control strategy and its feasibility of power smoothing in the photovoltaic power station by using the flywheel battery.