微网储能变流器平滑切换控制方法的研究

Research on Smooth Switching Control Method for Micro-grid Power Converter System

针对微电网储能变流器系统常规切换过程中存在合闸冲击电流、电压波动等问题,本文提出了一种基于相位同步的控制器状态跟随平滑切换控制策略,采用输出闭环跟踪的V/f控制和P/Q控制相互切换的方法。离网转并网时,将V/f控制器的输出状态跟随到P/Q控制器的输出;并网转离网时,将P/Q控制器输出状态跟随到V/f控制器的输出;在离网重新转并网时引入相位同步模块,使离网时的相位角与并网相位角同步。最后,基于Matlab建立储能变流器平滑切换仿真模型。仿真结果表明,该方法能够有效抑制微电网储能变流器平滑切换过程中电压波动并降低冲击电流。

To solve the problems such as the switching impulse current and voltage fluctuations during the conventional switching process of a micro-grid power converter system(PCS),a state-following smooth switching control strategy based on phase synchronization is proposed in this paper,in which the V/f control and P/Q control of output closed-loop tracking are switched between each other.When the off-grid mode is switched to grid-connected mode,the output state of the V/f controller follows that of the P/Q controller;when the grid-connected mode is switched to off-grid mode,the output state of the P/Q controller follows that of the V/f controller;when the off-grid mode is switched to grid-connected mode again,a phase synchronization module is introduced to synchronize the off-grid and grid-connected phase angles.Finally,a simulation model for the smooth switching of PCS is established based on Matlab,and simulation results show that this method can effectively suppress voltage fluctuations and reduce the impulse current during the smooth switching process of the micro-grid PCS.