【摘要】 为避免电网非对称故障时直驱永磁风电机组发生脱网事故,分析了电网电压不对称跌落时机、网侧能量不平衡引起直流链电容电压骤升的机理,提出了一种并联超级电容储能与序分量协调控制策略。考虑了电网非对称故障时电压的跌落程度、传动系统的储能限度和变流器的约束条件,通过对机、网侧变流器进行双闭环控制,实现快速平衡母线有功功率,同时补偿无功以改善电网电压。根据超级电容器寿命等影响因素选取电容容量,采用DC-DC变换器对超级电容的储能模式进行控制,限制故障阶段直流链支撑电容的电压。仿真结果表明了控制策略的有效性,提高了直驱永磁风电系统非对称故障的穿越能力和运行稳定性。更多还原

【Abstract】 In order to avoid an off-grid accident of a direct-drive permanent magnet wind turbine during asymmetrical grid faults, when the grid voltage drops asymmetrically, the mechanism of the DC link capacitor voltage swell caused by the unbalanced energy of the generator side and the grid side is analyzed. A coordinated control strategy of parallel super capacitor energy storage and sequence component is proposed. Some factors are considered such as the voltage drop degree of the power grid during asymmetrical faults, the energy storage limit of the drive system, and the constraints of the converter. Through the double closed-loop control of the generator and the grid side converters, the active power of the busbar can be quickly balanced, and reactive power can be compensated to improve the grid voltage. The capacity of the capacitor is selected according to the life of the super capacitor and other influencing factors, and the DC-DC converter is used to control the energy storage mode of the super capacitor to limit the voltage of the DC link supporting capacitor in the fault phase. The simulation results show the effectiveness of the control strategy and improve the asymmetric fault ride-through capability and operational stability of the direct-drive permanent magnet wind power system.更多还原