三电平脉冲宽度调制整流器定频直接功率控制

在传统的直接功率控制和电压定向控制的基础上,给出了三电平脉冲宽度调制整流器的数学模型,提出了一种固定开关频率的三电平脉冲宽度调制整流器直接功率控制方法。该控制结构为直流电压外环、功率控制内环,实现了有功功率和无功功率的动态解耦,且采用空间电压矢量调制,开关频率固定,简化了滤波器的设计。仿真结果表明,该控制方法能保证中点电位平衡、网侧电流谐波小,具有良好的动、静态性能,实现了单位功率因数运行。

Direct Power Control with Fixed Switching Frequency of Three-level Pulse Width Modulation Rectifier

The mathematical model of the three-level voltage source PWM rectifier was presented,then based on the traditional direct power control and voltage oriented control,a new direct power control method with fixed switching frequency for the three-level neutral-point clamped voltage source PWM rectifier was proposed.The new method used closed-loop DC voltage control as outside control and closed-loop power control as internal control,and the decoupling control between active and reactive power during the dynamic course had been realized.Besides,space voltage pulse width modulation was used to make the switching frequency fixed which would simplify the design of filter.Simulation results showed that the neutral-point potential balance could be ensured,harmonic distortion of current was low,dynamic and steady performance were both well,unity power factor could be achieved.