大功率高升压比光伏直流变压器控制策略

Control Strategy of High-power High-step-up Ratio Photovoltaic Direct Current Transformer

基于中频逆变和24脉波整流的高升压比直流变压器以其控制简单、可靠稳定等优点在大功率光伏直流汇集系统中具有广阔的应用前景。针对其中的交流并联逆变部分无同步电网及环流等问题,提出了一种基于中频逆变的功率主从控制策略,其中主机采用定直流电压控制,并建立电压同步矢量,提供基准电流,依据此基准电流采用功率控制策略,该方法在满足功率分配精度、减小环流的同时无需快速通讯,稳定性较高。最后通过仿真和实验结果验证了控制方案的可行性。

High-step-up ratio direct current transformer based on medium-frequency inversion and 24 pulse rectification has features of simple control and high reliability,its application to high-power photovoltaic system has broad prospects.Aiming at the problems of alternating current parallel inverter without synchronous power system and circulation,a power master-slave control scheme based on medium-frequency inversion is proposed.The master inverter adopts direct current voltage control and establishes voltage synchronization vector to provide reference current.According to reference current,the slave inverter adopts power control strategy.This method not only satisfies the accuracy of power distribution and reduces the circulation,but also does not need fast communication and has high stability.Finally,the feasibility of the control scheme is verified by the simulation and experimental results.