SMES提高DFIG低电压穿越能力策略研究

Operational Research on SMES for Improving DFIG Low Voltage Ride Through Capability

针对双馈型风力发电机组变流器直流母线过电压导致风机脱网问题,应用超导储能系统(SMES)的稳压结构并联于直流母线电容,在发生低电压故障时投入SMES,通过控制SMES快速吞吐电能达到稳定直流母线电容电压的目的,解决直流母线过电压问题;再者由于投入SMES稳定了直流母线电容电压,机侧变流器输出的有功量不再影响直流母线电容电压,就此提出投入SMES的双馈型风力发电机(DFIG)机侧变流器无功功率优先输出控制策略。在低电压故障结束后,网侧变流器通过控制有功功率输出量使SMES恢复到低电压故障前的存储电能初始值,提出网侧变流器平衡SMES电能的控制策略。

In order to solve the problem of double fed induction generator(DFIG)disconnection caused by DC bus overvoltage.A stable voltage structure of superconductor magnetics energy storage(SMES)is proposed,which is connected to DC bus capacitor in parallel.SMES is put into operation when low voltage fault occurs,and the DC bus capacitor voltage can be stabilized by controlling the SMES fast throughput power,so as to solve the problem of DC bus overvoltage.Furthermore,since SMES stabilizes the DC bus capacitor voltage,the active power output of the DFIG side converter no longer affects the DC bus capacitor voltage.Therefore,a reactive power priority output control strategy of the DFIG side converter with SMES is proposed.After the low voltage fault,the grid-side converter restores the SMES to the initial value of stored energy before the low voltage fault by controlling the active power output.A control strategy for balancing the SMES energy of the grid-side converter is proposed.