定子双绕组异步风力发电机组并网运行控制机理研究

Distributed generation based on power electronic device interface has smaller inertia than the conventional synchronous generator and no regulatory function for frequency and voltage. A large number of them will trigger the instability problem of the electrical power grid. And that operated interface with micro-grid will reduce the inertia of the power system and increase voltage fluctuation for unable to establish energy balance instantly in the transient process, which is unfavorable for the stability of micro-grid power system. For the first time employing the virtual synchronous generator technology in the dual stator-winding induction generator (DWIG) wind power system for grid-connected operation is proposed in this project. The whole DWIG wind turbine is operated to mimic the behavior of an SG for improving system inertia, and having regulation function for frequency and voltage will promote system stability. The integrated control strategy helps to enhance the stability of the output frequency and voltage, realizing flexible integration into the electrical power grid and tracking maximum wind power. The grid-fault-ride-through is carried out by integrated designing the phase-locked loop, current limiter and grid detection device and coordinated control of the whole unit. The improved reactive power compensation detection method is adopted for isolated island operation. For operation interface with micro-grid, adjusting the output active power by its own inertia and energy storage on the DC side is used to regulate the frequency of micro-grids, and the voltage of micro-grids is supported by regulating output reactive power on the basis of the voltage fluctuation accomplished by the grid-connected inverter. The success of the project will lay a foundation for the theory and application of the grid-connected DWIG wind power system.

基于电力电子装置接口的分布式电源相对于常规同步发电机惯性很小，且无法体现频率电压的调节功能，大量并入电网会引发稳定性问题，接入微网亦会降低微网惯性，使得系统无法瞬间建立能量平衡，增大电压频率波动，降低微网稳定性。项目提出在定子双绕组异步风电系统中首次采用电压源型虚拟同步发电机技术实现并网运行，将整个机组模拟成同步发电机，增加系统惯性，体现调频调压控制特性，促进电网和微网稳定。利用机组整体运行控制策略提高输出频率和电压的稳定性，实现柔性并网和最大风能跟踪；综合设计锁相环、电流限制器和电网检测环节，借助机组协调控制实现电网故障下运行；采取改进型无功补偿检测方法实现孤岛运行；针对微网运行，通过机组自身惯性和直流侧电容储能，调节机组输出有功，主动参与微网频率调节；根据微网电压变化由并网逆变器调节输出无功，支撑微网电压。本项目的成功开展将为定子双绕组异步风电系统的并网运行奠定理论和应用基础。

基于电力电子装置接口的分布式电源相对于常规同步发电机惯性很小，且无法体现频率电压的调节功能，大量并入电网会引发稳定性问题，接入微网亦会降低微网惯性，使得系统无法瞬间建立能量平衡，增大电压频率波动，降低微网稳定性。项目提出在定子双绕组异步风电系统中首次采用电压源型虚拟同步发电机技术实现并网运行，将整个机组模拟成同步发电机，增加系统惯性，体现调频调压控制特性，促进电网和微网稳定。利用机组整体运行控制策略提高输出频率和电压的稳定性，实现柔性并网和最大风能跟踪；综合设计锁相环、电流限制器和电网检测环节，借助机组协调控制实现电网故障下运行；采取改进型无功补偿检测方法实现孤岛运行；针对微网运行，通过机组自身惯性和直流侧电容储能，调节机组输出有功，主动参与微网频率调节；根据微网电压变化由并网逆变器调节输出无功，支撑微网电压。本项目的成功开展将为定子双绕组异步风电系统的并网运行奠定理论和应用基础。