基于虚拟直流电机的隔离型三端口直流变换器控制策略研究

Study on Virtual DC Machine Control Strategy Based on Isolated Three-port Converter

近年来,直流微网因其供电可靠性高、成本低、无频率和功角稳定性等优点受到广泛的关注。然而,由于直流配网中缺乏旋转储能设备,从而体现出低惯性、低阻尼的特点,母线电压受负载功率变化的影响明显。为了提高直流微网的支撑能力,针对应用于直流微网中的隔离型三端口直流变换器,本文将虚拟直流电机控制策略应用到隔离三端口直流变换器中。该控制策略通过引入直流电机的特性方程,使得隔离型三端口直流变换器具有直流电机的惯性及阻尼特性。当直流母线电压因负载切换产生电压波动时,该控制策略能够提供良好的功率支撑,有效缓解瞬时功率的冲击,降低直流母线电压的波动,提升电压质量。最后通过仿真验证了控制策略的有效性。

In recent years,DC microgrid has received wide attention due to its advantages such as high reliability of power supply,low cost,and no frequency and power angle stability problems.However,due to the lack of rotating energy storage devices in DC distribution networks,thus reflecting the characteristics of low inertia and low damping,the bus voltage is significantly affected by load power variations.In order to improve the support capability of DC microgrid,the virtual DC machine control strategy is applied to the isolated three-port DC converter for the isolated three-port DC converter applied in DC microgrid.By introducing the characteristic equations of DC motor,this control strategy makes the isolated three-port DC converter have possess the inertia and damping characteristics of DC motor.When the DC bus voltage fluctuates due to load switching,this control strategy can provide good power support,effectively mitigate the transient power impact,reduce the DC bus voltage fluctuation,and improve the voltage quality.Finally,the effectiveness of the control strategy is verified by simulation.