电压型并网逆变器的冲击电流抑制新方法

A new approach of suppressing impulse currents for voltage-type inverters

针对传统电压型并网逆变器存在冲击电流问题,从变换器电路结构对冲击电流影响的新角度,提出了一种改进的并网逆变器拓扑,其主要特征是设计有内置电阻.通过仿真分析发现,相比传统并网,有内置电阻的并网逆变器并网时的冲击电流抑制效果更好.然后,通过传递函数建立数学模型,对内置电阻下并网能抑制冲击电流的原因进行理论分析,指出原因在于这种情况下产生更小的幅值差,且能消除相位差,并给出了内置电阻的参数设计方法.最后通过实验验证了内置电阻抑制冲击电流的效果,证明了理论分析的正确性.

The traditional grid-connected inverter has impulse current problems. An improved topology of grid- connected inverters with built-in resistance was proposed from the point of the impact of converter circuit structure on impulse currents. Simulation analysis showed that the grid-connected inverter with built-in resistance had a better effect of inhibiting impulse currents during the grid-connected time. The mathematical model of transfer function was built to analyze the reason that impulse currents were inhibited when the inverter with built-in resistance was grid-connected. In this case it would produce smaller magnitude difference and eliminate phase difference. The design method of the parameter of built-in resistance was given. Finally it was verified through experiments that the built-in resistance could restrain impulse currents and the correctness of theoretical analysis was proved.