基于转子基波电压协同输出控制的双馈变流器高电压穿越策略

Research on the High Voltage Ride Through the Method for the Doubly-Fed Converter Based on the Coordinated Output Control of Rotor Fundamental Wave Voltage

为了解决电网电压深度不对称骤升时,机侧变流器功率不稳定以及直流母线脉动问题,提出一种基于转子基波电压协同输出控制的双馈变流器高电压穿越方法。当电网电压不对称升高时,转子侧变流器只输出转子电压基波分量,控制转子变流器输出有功功率基本为零,同时网侧变流器把直流母线的脉动功率送至电网。试验结果表明,该控制方案不仅可以保证在电网电压不对称升高期间双馈风电机组不脱网运行,还能向电网提供一定的感性无功功率,同时该方法不需要使用直流母线电压斩波电路,节省了成本。

In view of the problems of the asymmetric rise in the voltage depth of power grid, the instability of the power in the side converter, as well as the pulsation in DC bus, a proposal has thus been proposed of the high voltage ride through the method for the doubly-fed converter based on the coordinated output of rotor fundamental wave voltage. When the voltage asymmetry increases, there is only an output of the fundamental components of rotor voltage from the rotor side converter, with the output power of the control rotor converter being basically zero, and the pulsating power of the DC bus simultaneously transported to the power grid by the grid side converter. The experimental results show that the proposed control scheme can not only ensure that the doubly-fed wind turbine does not take off the grid with the rise of asymmetry grid voltage, but also provide a certain inductive reactive power to the power grid. Meanwhile, the cost can be saved due to the fact that the proposed method does not need the chopper circuit of the DC bus voltage.