Research On Control Strategy Of High-Temperature Superconducting Magnetic Energy Storage System Based On DSP2812

With the development of EHV AC and DC long-distance transmission, increase of renewable energy generation and the formation of the national large scale power grid, the dynamic stability of power has become increasingly prominent. Superconducting energy storage system (SMES) with the advantages of large storage capacity, high efficiency, quick response and flexible to use, can exchange the active and reactive power with power system quickly and efficiently, and will play an important role in improving power quality and reliability.For the power conversion system between the superconducting magnets and power grid, the control strategy of SMES converter is one of key technologies to achieve good performance for the system. By using mature control technology and a common control system for power exchange, voltage source converter (VSC) for SMES combined with a chopper and a converter,can isolate the magnet from the direct impact of power system, and contribute to the stable operation of the superconducting magnet. Meanwhile, with high-speed computing power and corresponding peripheral functions, DSP2812 is suitable for operation control algorithm of SMES converter.In this paper, working principles and the chopper charging and discharging modes are analyzed for VSC of SMES under the three-phase equilibrium condition. The switching function, the dq axis mathematical models of VSC and charging and discharging mathematical model of chopper are established. At the same time, current inner loop control method for VSC and hysteresis control strategy for chopper are discussed and studied. Synchronous PI current and voltage loop controller for VSC using SVPWM method and current/voltage regulator for chopper are designed respectively. Based on DSP2812, the control strategy softwares are programed and debugged. The hardware circuits are built for the SMES converter device. Simulation and experimental results demonstrate that the control strategy can achieve the energy excharge betwwen superconducting magnets and power grid in unit power factor.