基于动态电压补偿的VSG电流平衡及峰值电流控制

Current Balance and Peak Current Control of Virtual Synchronous Generator Based on Dynamic Voltage Compensation

虚拟同步发电机(VSG)能够实现新能源机组友好并网。然而,传统的VSG技术主要适用于电网电压平衡工况,这使得VSG在电压不平衡情况下面临输出电流不平衡及过流等问题,为此提出一种基于动态电压补偿的VSG平衡电流控制架构及方法。通过负序电流抑制和峰值电流抑制策略,分别生成对应的补偿电压,使得VSG在电压不平衡时仍能输出平衡电流,且可抑制电网电压跌落瞬间的暂态冲击,以及确保稳态运行时的电流不超过安全阈值。同时,所提控制方法并未改变VSG等效为电压源的属性,保留了VSG的电压支撑能力。不同工况下的仿真测试结果验证了所提出控制方法的正确性和有效性。

Virtual synchronous generator（VSG）can achieve friendly power grid integration of new renewable energy resource.However,traditional VSG technique is mainly applied in the voltage balanced situation,which leads to the unbalanced current output and overcurrent of VSG in the voltage unbalanced situation.A balanced current control strategy of VSG is therefore proposed based on the dynamic voltage compensation.By suppressing negative sequence current and controlling peak current,the corresponding compensating voltage is generated,which guarantees that the current of VSG is balanced in the unbalanced grid,the transient impact at the moment of voltage dip is suppressed,and the stable peak current is limited.Simultaneously,the proposed control strategy does not change the voltage source property of VSG,which retains the voltage support ability of VSG.Finally,the test simulation results under different operating conditions verify the correctness and effectiveness of the proposed control strategy.