Abstract: A power distribution system includes: a distribution unit that splits a supply AC current Ip from an external AC power supply 2 into a first distributed AC current and a second distributed AC current and distributes the first distributed AC current to a first load; a current monitoring unit that monitors the supply AC current Ip; a bidirectional AC-DC converter that converts, when operated as an AC-DC converter, the second distributed AC current distributed from the distribution unit into a supply DC current and supplies the supply DC current to a second load 5 and that converts, when operated as a DC-AC inverter, a regenerative DC current from the second load into a regenerative AC current and supplies the regenerative AC current to the first load; and a control unit that controls the bidirectional AC-DC converter based on the supply AC current Ip monitored by the monitoring unit.

Abstract: The command signal processing unit outputs, when a first PWM frequency command signal is received, a high-PWM frequency command signal such that an asynchronous PWM control is performed at a PWM frequency of a predetermined constant frequency. The command signal processing unit outputs, when a second PWM frequency command signal is received, a low-PWM frequency command signal such that an asynchronous or synchronous PWM control is performed at a frequency lower than the above-described frequency. The PWM frequency control unit controls the PWM frequency such that an asynchronous PWM control is performed if a motor has a rotational speed less than a predetermined rotational speed and that a synchronous PWM control is performed if the motor has a rotational speed greater than or equal to the predetermined rotational speed, when a low-PWM frequency command signal is input.

Abstract: The command signal processing unit outputs, when a first PWM frequency command signal is received, a high-PWM frequency command signal such that an asynchronous PWM control is performed at a PWM frequency of a predetermined constant frequency. The command signal processing unit outputs, when a second PWM frequency command signal is received, a low-PWM frequency command signal such that an asynchronous or synchronous PWM control is performed at a frequency lower than the above-described frequency. The PWM frequency control unit controls the PWM frequency such that an asynchronous PWM control is performed if a motor has a rotational speed less than a predetermined rotational speed and that a synchronous PWM control is performed if the motor has a rotational speed greater than or equal to the predetermined rotational speed, when a low-PWM frequency command signal is input.