Patent ID: 9602039
Date: 2017-03-21
CPC Classifications: H02P

Claim:
1. A PWM rectifier connected through an electric storage device capable of storing DC power to DC side of an inverter performing a power conversion between the DC power and AC power which is drive power or regenerative power of a motor, the PWM rectifier comprising: a main circuit unit in which a switching operation of a switching element is PWM-controlled on the basis of a PWM control signal received, and which performs a power conversion between AC power on an AC power supply side and the DC power on the DC side; a DC voltage loop control unit which generates a current command to cause the DC voltage value on the DC side of the main circuit unit to match a DC voltage command received; a current command restriction unit which sets, when an absolute value of the current command exceeds a limit value predetermined, the limit value as a final current command, and otherwise sets the current command as the final current command; a DC voltage loop saturation determination unit which determines that the DC voltage loop control unit is in a saturation state when the current command restriction unit sets the limit value as the final current command and otherwise determines that the DC voltage loop control unit is in a non-saturation state; a DC voltage command calculation unit which maintains the DC voltage command when the DC voltage loop saturation determination unit determines the non-saturation state, and changes the DC voltage command into a value obtained by adding a predetermined offset to a minimum value or a maximum value of the DC voltage value after a transition to the saturation state from the non-saturation state when the DC voltage loop saturation determination unit determines the saturation state; and a PWM control signal generation unit which generates the PWM control signal using the final current command to output the PWM control signal to the main circuit unit.