单相Z/Q-Z源逆变器的无差拍并网控制策略

摘要

In order to improve the efficiency of Z/Q-Z source inverter and output current quality,reduce the harmonic distortion rate of grid-connected current,the control strategy of grid-connected current is applied to the Z/Q-Z source inverter.The deadbeat control is used to realize grid-connection control,The current can track the reference current quickly,realize the single power factor operation,and the digital control of the inverter.Z/Q-Z source grid-connected inverter simulation model is established,and the grid-connected system of Z/Q-Z source inverter is simulated and analyzed to prove the validity and feasibility of the grid-connected control strategy.The simulation results show that the total harmonic distortion rate of the grid-connected current is less than 1％,the quality of grid-connected current is improved,and the capacitor voltage value of Q-Z source inverter is about half order of magnitude smaller than the Z inverter network.Moreover soft start control of the Z/Q-Z source inverter is analyzed,soft start can effectively solve the start impact of the Z source capacitor voltage and inverter bridge voltage.%为了提高Z/Q-Z源逆变器效率、输出电流质量,减小并网电流谐波畸变率,将无差拍并网电流控制策略应用到Z/Q-Z源逆变器中.采用无差拍算法对Z/Q-Z源逆变器进行并网控制,并网电流能够快速跟踪参考电流,实现逆变器单功率因数运行,以及逆变器的数字化控制.建立Z/Q-Z源并网逆变器仿真模型,并对Z/Q-Z源逆变器并网系统进行仿真分析,证明采用无差拍算法并网控制策略的正确性与可行性.仿真结果表明:并网电流总谐波畸变率小于1％,提高了并网电流质量,且Q-Z源逆变器比Z逆变器网络中电容电压值减小半个数量级.另对Z/Q-Z源逆变器进行软启动控制仿真分析,软启动可以有效解决Z源电容电压、逆变桥电压的启动冲击等问题.