Abstract: Single-phase inverters are widely used in many fields, but there are inherent double frequency problems, and double frequency fluctuations can easily cause system instability. This paper proposed a mid-point common-mode injection power decoupling circuit. The advantage of this topology is that no additional switching devices are needed, and only the original support capacitors and filter capacitors on both sides of the H-bridge inverter can be used to buffer the double frequency power and realize the solution. The entire decoupling control algorithm is simple and easy to implement in a single-phase differential inverter. Another feature is that the topology uses the AC-side filter capacitor and the DC-side support capacitor to be connected at the midpoint to construct a half-bridge differential inverter structure. The AC-side capacitor can operate in positive and negative directions while reducing the withstand voltage of the decoupling capacitor. The half-bridge structure not only improves the utilization of the capacitor, but also promotes the increase of power density in the selection of the capacitor. The simulation and experimental results further prove that the method can effectively suppress the double ripple on the DC side, and the data proves that the topology can effectively improve the system efficiency.