一种基于内模控制的光伏逆变器功率控制策略

为改善微电网电能质量,解决微电网独立控制有功和无功控制问题,分析了两电平三相三线制电压源逆变器的控制方案,建立数学模型,运用瞬时功率理论推导出参考电流计算公式,提出由内外两层组成的串级控制策略。内层控制器采用内模一阶过程控制技术调节q轴和d轴的交流电流实现电流控制,外层控制器采用内模二阶过程的前馈控制策略实现直流母线电压控制。通过仿真验证,该控制策略可以有效的进行微电网逆变器有功和无功控制,实现逆变器跟随电网电压跌落自动调节直流侧电压功能,为改善微电网电能质量控制研究提供了一种新方法。

A Power Control Strategy of Photovoltaic Inverter Based on Internal Model Control

To improve micro-grid power quality and solve the problem that micro-grid controls active and reactive power by itself, the control scheme of two level source inverter of three-phase three-wire voltage system is analyzed. Then the mathematical model is constituted, the expression of reference current is deduced by instantaneous power theory, and the cascade control micro-grid inverter structure is proposed which is composed of inter and outer controllers. On one hand, the internal model control with one-order process is put forward to realize current control by adjusting alternating current of axis and axis. On the other hand, the feed forward control of internal model with two-order process is presented to achieve DC bus voltage control in the outer controller. Through simulation verification, the control strategy can be effective for active and reactive power control of micro grid inverter, also the inverter can follow grid voltage sag and self-adjust DC bus voltage. So the new strategy is provided for the study to improve power quality of micro-grid.