入网电压控制型逆变器直流分量的动态分析与消除

针对入网电压控制型逆变器的并网电流直流注入问题进行研究。基于轴压调节控制型的单相LCL型并网逆变器,建立并网数学模型,并结合逆变器的控制结构对并网电流注入直流分量的原因进行详细的数学分析与公式推导,结果表明直流分量的大小与电网电压幅值和频率的变化量近似呈线性关系。同时为了抑制和消除直流分量对逆变器并网系统所带来的不利影响,提出电流偏移补偿(CDC)控制策略,该策略在电网电压幅值波动和电网频率波动时能够有效地补偿并网电流中的直流分量,保证入网电压控制型逆变器优良的控制性能。最后,通过仿真和实验验证了理论分析的正确性与所提控制策略的有效性。

Dynamic Analysis and Elimination of DC Component of Grid Connected Voltage Controlled Inverter

This paper focusses on the problem of direct current injection caused by voltage-controlled inverter connection. Based on the axial-voltage regulation single phase LCL inverter, the mathematical model of grid connected inverter has been built. This paper shows the details of mathematical analysis and formula derivation by analyzing the reasons of DC component indection. The result shows that the DC component has a nearly linear relationship with the voltage amplitude and frequency. Thus, this paper proposes the current deviation compensation (CDC) control strategy to diminish and eliminate the impacts of DC component. This strategy can compensate the injection direct current when the grid voltage and frequency fluctuation happen. The CDC control can also improve the performance of voltage-controlled inverter at the same time. Finally, simulation and experiment verify the effectiveness of the proposed control strategy.