Patent ID: 9602019
Date: 2017-03-21
CPC Classifications: H02M,Y02B

Claim:
1. A voltage-adjusting device applied in a power conversion system, the power conversion system comprising a Vienna rectifier, a DC bus, and an inverter, the Vienna rectifier converting a three-phase AC voltage of a grid to a DC bus voltage, the inverter being electrically coupled to the DC bus and generating a three-phase AC signal based on the DC bus voltage transmitted by the DC bus, the voltage-adjusting device comprising: a grid voltage sampling module, electrically coupled to the grid, for sampling a grid voltage; a given bus voltage calculating module for calculating a given DC bus voltage based on the grid voltage; a voltage-adjusting module for receiving the DC bus voltage and the given DC bus voltage, and outputting an active current given signal based on the DC bus voltage and the given DC bus voltage; a current control module electrically coupled to the voltage-adjusting module, which is configured for receiving a three-phase AC current from the grid, the active current given signal and the reactive current given signal to output a three-phase control voltage; a pulse width modulation (PWM) module for receiving the three-phase control voltage and the DC bus voltage to output a pulse control signal to the Vienna rectifier; and a rectifier switch control module for receiving the DC bus voltage and comparing it with a DC bus voltage threshold, and outputting a switch control signal according to a comparison result, wherein the pulse width modulation module outputs the pulse control signal based on the three-phase control voltage, the DC bus voltage and the switch control signal.