Renewable energy sources cannot guarantee long-term and stable output supply when they are given energy consumption at the load end. At the same time, traditional solar and utility power supply system cannot guarantee the priority of using solar energy to generate electricity, which has certain limitations. In this regard, an energy control strategy for achieving smooth and no backflow switching and prioritizing the use of clean energy solar energy under a joint power supply system of a solar power grid and a municipal power grid is proposed, which is used for a conventional combined power supply system of a contactor switching circuit. A new combined power supply topology is proposed, which effectively reduces the impact on the solar power grid and the municipal power grid during the system switching process combined control mode for controlling the current phase and repetitive control at the output end of the solar power grid in the combined power supply mode and adding a feedforward control method for the grid voltage is adopted to ensure that the solar grid and the municipal power, and prioritise the use of clean energy solar energy. And at the same time, ensure the maximum utilisation of solar energy. In order to further validate energy control strategy, this paper chose the combined power supply system with solar power grid and the municipal power grid as the object of this research the topology structure and controlling strategy of the power supply system were comprehensively and deeply researched, and on this basis, the combined power supply system prototype was designed on the foundation of DSP28335 and CPLD. And hardware parameters are designed in the system, and an energy management optimisation algorithm based on the system is developed on the corresponding experimental platform. The experimental results show that the proposed energy control strategy can effectively reduce the impact on the solar power grid and the municipal power grid during the system switching process, ensure that the solar power grid and the municipal power grid have no backflow combined power supply, and give priority to the use of clean energy solar energy.