In order to realize the voltage equalization and minimize the total harmonic distortion rate of current of cascaded multilevel rectifier with common high voltage Direct Current (HVDC) bus, the cascaded multilevel rectifier with common high voltage DC bus and its control method are studied.
The output side DC voltage of the cascade multilevel rectifier with common high voltage DC bus is sampled, and the output DC current signal amplitude is obtained according to the calculated output side DC voltage signal. On this basis, the AC side voltage corresponding to the applied switching
state and the switching state corresponding to the rectifier in the sampling period are solved. The driving signal of the switch device is generated and sent to the corresponding switch device to realize the active power factor correction and sinusoidal input current, so as to realize the
balanced control of output DC capacitor voltage of cascaded multilevel rectifier with common High-Voltage Direct Current (HVDC) bus. The test results show that this method can effectively control the three-phase output current of the rectifier and ensure the maximum output of the current.
The lowest total harmonic distortion rate of the output phase voltage is about 40%, which can effectively ensure the stability of the output phase voltage after control.