无电压传感器的三电平PWM整流器定频直接功率控制

Direct Power Control with Fixed Switching Frequency of Three-level PWM Rectifier Without Grid Voltage Sensors

给出了三电平PWM整流器的数学模型,在传统的直接功率控制和电压定向控制的基础上,结合虚拟磁链控制的优点,提出了一种新的三电平PWM整流器定频直接功率控制方法。该控制方法省略了电网电压传感器,实现了有功功率和无功功率的动态解耦,调制环节采用空间电压矢量调制,开关频率固定。仿真结果表明,该控制方法实现了单位功率因数运行,网侧电流谐波小,具有良好的动静态性能,保证了中点电位的平衡。

The mathematical model of the three-level voltage source PWM rectifier is presented, then based on the traditional direct power control and voltage oriented control and combing the advantages of virtual flux control, a new direct power control method with fixed switching frequency for the three-level neutral-point clamped voltage source PWM rectifier is proposed. In the new method, voltage sensors of grid side are eliminated, and the decoupling control between active and reactive power during the dynamic course has been realized.Besides, space voltage pulse width modulation is used to make the switching frequency fixed.Simulation results show that the unity power factor can be achieved, harmonic distortion of current is low, dynamic and steady performance are both well, and the neutral-point potential balance can be ensured.