抑制IGBT器件结温的双馈风电变流器分段DSVPWM策略

针对双馈风电机组机侧变流器绝缘栅双极型晶体管(IGBT)结温波动大的问题,提出了一种抑制IGBT结温且不影响机组运行性能的机侧变流器调制策略。首先,基于不连续空间矢量调制(DSVPWM)在一定负载功率因数角可降低变流器开关损耗的思路,通过推导双馈风电机组机侧变流器功率因数角表达式,详细分析了机侧变流器功率因数角的变化范围。其次,为了有效抑制IGBT结温,针对机侧变流器功率因数角变化范围大的问题,提出以机侧变流器功率因数角变化范围为依据的分段DSVPWM策略。最后,建立了考虑IGBT热性能的双馈风电变流器电-热耦合模型,对机组不同出力下的变流器电-热性能进行了仿真分析。结果表明,与传统连续空间矢量调制(CSVPWM)策略相比,所提出的分段DSVPWM策略能有效抑制机侧变流器IGBT结温及结温波动。

Segmented DSVPWM strategy to depress IGBT junction temperature of wind-power converter

Aiming at the large IGBT(Insulated Gate Bipolar Transistor) junction temperature fluctuation of the rotor-side converter of doubly-fed wind turbine-generator, a modulation strategy is proposed to depress the IGBT junction temperature without affecting the operation performance of system. A power-factor angle expression of rotor-side converter is derived based on the concept that the DSVPWM(Discontinuous Space Vector Pulse Width Modulation) at a certain load power-factor angle can reduce the switching loss of converter and its variation range is analyzed. Since the variation range is quite large, a segmented DSVPWM strategy according to the power-factor angle variation range of rotor-side converter is proposed to depress its IGBT junction temperature. An electric-thermal coupling model considering the thermal performance of converter IGBT is established for a 2 MW doubly-fed turbine-generator system, and the electric-thermal performance of converter is simulated and analyzed for different power outputs, which show that, compared with the continuous space vector pulse width modulation, the proposed segmented DSVPWM strategy can effectively depress the IGBT junction temperature of the rotor-side converter and its fluctuation.