基于电流反馈的同步逆变器功率解耦控制策略

Power Decoupling Control Strategy of Synchronverter Based on Current Feedback

同步逆变器通过模拟同步电机内部机理和外部特性使其对电网具有天然友好的特性,但其有功功率和无功功率之间存在的耦合会加剧同步频率谐振,容易引发功率振荡,导致系统不稳定。本文首先建立同步逆变器功角特性的小信号模型,分析产生功率耦合的机理。在此基础上,针对功率耦合问题提出了一种新型的功率解耦控制方法：通过添加反馈电流环对耦合功率进行动态补偿,将引起耦合的动态功率量转换成动态电流的形式,消除了由功率耦合引起的动态功率振荡和虚拟同步控制的稳态误差,并对加入反馈电流环的控制系统进行了稳定性分析,最后通过仿真验证了该方法的有效性和可行性。

Synchronverter has natural friendly characteristics to the grid by simulating the internal mechanism and external feature of the synchronous motor, however, the coupling between active and reactive power intensifies synchronous frequency resonance, triggers power oscillations and results system instability. Therefore, the small signal model of the synchronverter power angle characteristics is firstly established to analyze the production mechanism of the power coupling. Aiming at the problem of power coupling, a new power decoupling control method is proposed. The coupling power is dynamically compensated by adding a feedback current loop, realizing the way that convert the dynamic power quantity which causes the coupling into the form of dynamic current, and eliminating the steady-state error and dynamic power oscillation of virtual synchronization control caused by power coupling. The stability analysis of the control system with feedback current loop is presented. Simulation are given to show the validity and feasibility of the proposed control strategy.