基于改进双矢量模型预测控制的逆变器功率均分控制策略

Inverter Power Equalization Control Strategy Based on Improved Dual-Vector Model Predictive Control

在低压微电网中,由于线路阻抗的不匹配问题,导致传统的并联逆变器系统无法实现功率的精确均分,且系统间存在较大环流。对此,在分析逆变器功率均分机理和环流特性的基础上,提出一种无需通信的自调节虚拟阻抗控制策略,引入虚拟负感抗抵消线路的感性成分,保证功率解耦,以环流作为反馈信号自动调节虚拟阻抗项,有效实现了有功功率的均匀分配以及环流的抑制。同时,提出一种改进双矢量模型预测控制(model predictive control,MPC)策略对矢量作用时间进行重构,降低系统输出电流的谐波含量,实现电压矢量的全局最优控制。仿真和实验结果表明,所提控制策略能够使并联系统均分负载功率,对环流有明显的抑制作用,系统动态响应性能得到提升,验证了控制策略的可行性及有效性。

In low-voltage microgrids,the mismatch in the line impedance prevents traditional shunt inverter systems from achieving precise power equalization,leading to significant circulating current between the systems.In this regard,based on an analysis of the inverter power equalization mechanism and circulating current characteristics,this study proposes a selfregulating virtual impedance control strategy without communication.This strategy introduces a virtual negative inductive impedance to offset the inductive component of the line,ensuring power decoupling.It automatically adjusts the virtual impedance term using the circulating current as the feedback signal,effectively realizing an even distribution of active power and suppressing the circulating current.Additionally,an improved dual-vector model predictive control strategy was proposed to reconstruct the vector action time,reducing the harmonic content of the system output current and realizing global optimal control of the voltage vector.Simulation and experimental results show that the proposed control strategy ensures that the parallel system divides the load power equally and significantly suppresses the circulating current.The dynamic response performance of the system has been significantly improved,verifying the feasibility and effectiveness of the control strategy.