适合直接驱动型风力发电系统的DRC混合箝位变流器研究

DRC-clamped inverter for direct-drive wind power system

针对直接驱动型风力发电系统中需要的全功率变流器,提出了一种基于箝位二极管、电阻、电容DRC (Diode Resistor Capacitor)混合箝位的三电平变流器,并采用载波相移正弦脉宽调制CPS-SPWM(Carrier phase shifted SPWM)技术产生控制脉冲。仿真结果表明,该变流器输出波形正确,等效开关频率提高了1倍,最低次载波谐波移至载波频率2倍的位置,并具有自动平衡电容电压,电容充放电电流呈周期性变化且无电流尖峰冲击等优点。

For the full power inverter needed in direct-drive wind power system, a DRC（Diode Resistor Capacitor） clamped three-level inverter is proposed, in which CSP-SPWM（Carrier Phase Shifted PWM） technology is used to generate control pulses. Simulation results show that, the output voltage is fine, the equivalent switching frequency is doubled, the lowest harmonic component is two times of carrier frequency, the capacity voltage is balanced automatically and the charge/discharge current of capacity varies periodically without current impact.