容性等效输出阻抗的逆变器并联控制研究

摘要

并联逆变器的等效输出阻抗一般设计呈感性、阻性及阻感性。通过合理的控制方法和合适的参数设计，在以上三种等效输出阻抗形式下，均可实现微网中的多逆变器并联控制。为进一步寻求更优的并联控制策略，建立了两台逆变器并联运行系统模型，通过引入虚拟阻抗，将逆变器输出阻抗设计呈电容性，推导出了容性等效输出阻抗条件下的下垂控制算法，提出了基于容性等效输出阻抗的鲁棒下垂控制策略。通过仿真分别对比了容性和感性、阻性等效输出阻抗条件下的功率均分特性，结果表明，容性等效输出阻抗条件下的多逆变器并联运行系统具有更好的性能。通过两台额定功率均为2 kVA的光伏逆变器并联系统平台验证了基于容性等效输出阻抗的鲁棒下垂控制策略的正确性。%The equivalent output impedance of paral el inverters could be designed to be inductive, resistive or resistance and inductance. With reasonable control methods and suitable design of parameters, under the above three kinds of equivalent output impedance form, the control of paral el inverters could be realized. To further study the paral el-control strategy, the model based on two paral el inverters was established through the introduction of virtual impedance. The droop control strategy based on the capacitive equivalent output impedance was deduced through the output impedance of the inverters which were designed to be capacitive. The robust droop control strategy based on capacitive equivalent output impedance was proposed. The power sharing characteristics under the capacitive, inductive, and resistive equivalent output impedance were compared. It shows that the multiple-inverter paral el system under the capacitive equivalent output impedance has better performance. In the photovoltaic inverter paral el system platform with two 2kVA inverters, the crorrection of robust droop control strategy based on capacitive equivalent output impedance was verified.