三相开关型功率放大器设计及零序环流抑制研究

Design of Three-phase Switching Power Amplifier and Research on Zero-sequence Circulating Current Suppression

摘要:

为了满足硬件在环测试、并网变换器测试等需求，设计了一种交-直-交三相功率放大器，并在逆变侧采用并联交错T型多电平拓扑，满足了高开关频率、大功率等级以及低损耗等需求。此外，分析了三相开关型功率放大器中零序环流的流通路径，提出了零序环流的等效模型，给出了零序环流的数学表达式，并在仿真实验中进行了验证。最后，提出采用共模电感代替工频变压器抑制环流，大大减小了装置体积，节约了成本，并在仿真实验中验证了该措施的有效性。

Abstract:

In order to meet the requirements of hardware-in-the-loop testing and grid- connected converter testing, an AC-DC-AC three-phase power amplifier is designed, and a parallel interleaved T-type multilevel topology on inverter side is adopted to meet high switching frequency, high power level and low loss requirements. In addition, the flow path of zero- sequence circulating current in three- phase switching power amplifier is analyzed, an equivalent model of zero-sequence circulating current is proposed, and the mathematical expression of zero-sequence circulating current is given, which is verified in simulation experiment. Finally, common-mode inductor is proposed to replace power frequency transformer to suppress circulating current, which can greatly reduce the device size and save cost, and the effectiveness of this measure is verified in the simulation experiment.