基于改进型电流控制策略的单相并网逆变装置研究

单相并网逆变装置的性能主要取决于其控制技术,传统的并网电流瞬时值单环PI控制虽然能够获得快速的动态性能,但不能保证输出电流幅值的精度且系统会受电网电压影响。针对以上问题,本文提出了并网电流平均值外环和瞬时值内环的双环控制策略,提高了系统的精度,并在内环加入电网电压前馈环节,消除了电网电压的干扰。通过仿真实验和样机对比实验证明了所提方案的有效性。

Research of single-phase grid-connected inverter based on improved current control strategy

The performance of the single phase grid-connected inverter depends mainly on its control technique.The traditional single-loop PI control of instantaneous value of grid current can make the system to gain fast dynamic performance,but is not capable to obtain high amplitude accuracy of the output current and the system will be interfered with by the grid voltage.To solve the above problems,a double-loop strategy of the mean value and instantaneous value of grid-current is proposed in this paper.The inner loop of the instantaneous value makes the output current of the inverter tracking the sinusoidal reference current quickly,while the outer loop of the mean value makes the amplitude of the output current equal to the one of the reference.So the solution proposed in this paper can help to obtain high accuracy and to offset the impact of the grid voltage with its the feed forward loop.The simulation and prototype experiments had verified that the proposal is effective.