用于漏电流抑制的正、反向钳位H10三相逆变器

H10 three-phase inverter with forward and reverse clamping circuit for leakage current suppression

针对非隔离光伏发电系统存在的漏电流问题,提出了正、反向两种不同钳位方式的十开关三相逆变器拓扑(H10拓扑)。在传统三相逆变器拓扑基础上增加了两个直流母线隔离开关以及一个钳位电路,两种拓扑区别在于钳位电路的钳位开关位置不同。同时对两种拓扑提出一种载波调制和逻辑运算相结合的通用控制策略。该控制策略能够使两种逆变器拓扑的共模电压幅值只在直流输入电压的1/3和2/3之间变化,但反向钳位逆变器拓扑的共模电压频率为正向钳位逆变器拓扑的3倍,高频状态下其共模回路阻抗显著增加,对于漏电流的抑制效果更加明显。最后搭建了两种逆变系统的仿真模型,以及每相输出功率200 W的实验样机,验证了理论分析的正确性。

To address the leakage current problem in non-isolated PV power generation systems,two tenswitch three-phase inverter topology(H10 topology)named forward-clamped and reverse-clamped H10 inverters were proposed.Both of the topologies were obtained by adding two DC bus isolating switches and a clamping circuit to the traditional three-phase inverter topology,but the difference between the two topologies lies in the positions of the clamping switches in the clamping circuit.A general control strategy combining carrier modulation and logic operation for these two topologies was proposed.The control strategy allows the common-mode voltage of these two topologies to vary only between 1/3 and 2/3 of the dc input voltage,but the frequency of the common-mode voltage of the reverse-clamped inverter topology is three times that of the forward-clamped inverter topology,and the impedance of the common-mode loop increases significantly at highly frequency,so the leakage current suppression capability is more obvious.Finally,simulations of the two inverter systems and an experimental prototype with 200 W output power per phase were built to verify correctness of the theoretical analysis.