微电网运行模式切换下储能变流器双无源控制策略

Dual-Passivity-Based Control Strategy for Energy Storage Converter under Microgrid Operation Mode Switching

在孤岛启动、孤岛负荷投切、非计划性离网等不利时刻,微电网母线电压频率的过大波动可能严重损害整个微电网的电气设备。被选作主逆变器的储能变流器,其控制性能对维持微电网电压频率稳定十分关键。因此,在严格证明储能变流器无源性的基础上,提出适用于微电网的双无源控制策略,以提高微电网安全稳定运行的能力。通过建立端口受控哈密尔顿模型、设立平衡点、求解能量匹配方程和阻尼参数校正,设计了基于孤岛电压环无源控制器和电流内环无源控制器的双无源控制策略。仿真结果验证了双无源控制可有效提高孤岛/并网运行模式切换下微电网电压频率的稳定性,更好保障微电网安全稳定运行。

At the unfavorable moments such as island startup, island load switching, and unplanned off-grid, the excessive fluctuation of microgrid bus voltage frequency may seriously damage the electrical equipment of the entire microgrid. The control performance of the energy storage converter selected as the main inverter is vital for maintaining the voltage and frequency stability of the microgrid. Therefore, on the basis of rigorously proving the passivity of the energy storage converter, a dual-passivity-based control strategy suitable for microgrid is proposed to improve the safe and stable operation of the microgrid. A passivity-based control strategy based on the island voltage loop passivity-based controller and the current inner loop passivity-based controller is designed through establishing a port-controlled Hamiltonian model, setting equilibrium points, solving energy matching equations, and correcting damping parameters. The simulation results have verified that the dual-passivity-based control can effectively improve the voltage and frequency stability of the microgrid under islanding/grid-connected operation mode switching, and better ensure the safe and stable operation of the microgrid.