直流微电网中接入的恒功率负载降低了系统的有效阻尼,导致直流母线上产生高频电压振荡,威胁系统的安全稳定运行.为此,提出一种基于有源电容的直流母线电压振荡抑制器及其控制方法,将振荡抑制器与直流母线并联,令其直接与直流母线进行能量交互,振荡抑制器中的储能电容可以有效存储直流母线上伴随电压振荡产生的瞬变能量,从而降低电压振荡幅值,提高母线电压的稳定性.振荡抑制器中电源的电压可跟随直流母线电压进行自适应调节,面对系统中负荷变化,振荡抑制器可以保持稳定工作,具有即插即用、适用性强、控制灵活的优点.此外,通过分析振荡抑制器的工作模态和机理,建立其小信号模型,分析控制器参数对振荡抑制器稳定性和动态特性的影响,得出控制器参数优化方案.最后通过实验验证了上述振荡抑制器的有效性.

The constant power load (CPL) in a DC microgrid can reduce the effective damping of the system, resulting in high frequency voltage oscillations on the DC bus, which threatens the safe and stable operation of the system. To address this issue, this paper proposes a DC-bus voltage oscillation suppressor based on an active capacitor and its control method. The oscillation suppressor is connected in parallel to the DC bus, enabling direct interaction with the DC bus. The energy storage capacitor in the oscillator suppressor effectively stores the transient energy generated by voltage oscillations, thereby reducing the amplitude of voltage oscillation and improving the voltage stability of the bus. The voltage of the power supply in the oscillation suppressor adapts to the voltage of the DC bus, allowing for stable operation in the face of load changes in the system. The design offers advantages such as plug-and-play functionality, strong applicability, and flexible control. In addition, by analyzing the operating mode and mechanism of the oscillation suppressor, a small signal model is established, and the influence of controller parameters on the stability and dynamic performance of the suppressor is analyzed, based on which the controller parameter optimization scheme is proposed. Finally, the effectiveness of the oscillatory suppressor is validated through the experimental results.