基于内模控制的逆变器并离网无缝切换策略研究

Research on seamless switching strategy of inverter betweeen grid-connected and off-grid based on internal model control

针对逆变器在并离网切换过程中存在电压畸变、冲击电流等问题,提出了一种基于虚拟同步发电机(VSG)控制和电压电流内模控制(IMC)的并离网无缝切换控制策略。首先,建立了逆变器整体控制结构以及数学模型。其次,设计了基于内模控制的电压电流双环控制结构,并对内模控制器进行参数整定。再次,采用基于电压幅值和相位的预同步控制方法使逆变器能在两种运行模式之间平滑切换,切换瞬间电压电流波形稳定,能实现平滑过渡。最后,通过Matlab/Simulink仿真验证了所提出控制策略的有效性。

This paper presents a seamless switching control strategy based on virtual synchronous generator(VSG) control and voltage and current internal model control(IMC) for voltage distortion and impulse current in the switching process betweeen grid-connected and off-grid of the Inverter. Firstly, the control structure and mathematical model of the inverter are established.Secondly, the control structure with voltage and current double-loop based on IMC is designed and the parameters of internal model controller are adjusted. Thirdly, the pre-synchronization control method based on amplitude and phase of the voltage is adopted to enable the inverter to switch smoothly between the two models, and the transient voltage and current of switching is stable, which realizes the smooth transition. Finally, the effectiveness of the proposed control strategy is verified by the Matlab/Simulink simulation.