Patent ID: 9013906
Filing Date: 2015-04-21
Classification: H02M

Abstract:
1. A power-system-interconnected inverter device comprising: a first three-level circuit including first, second, third and fourth preceding-stage switch elements connected in series between a first input end of a direct-current power supply and a neutral point and a first charging and discharging capacitor including a first end that is connected to a connection point between the first preceding-stage switch element and the second preceding-stage switch element and a second end that is connected to a connection point between the third preceding-stage switch element and the fourth preceding-stage switch element; a second three-level circuit including fifth, sixth, seventh and eighth preceding-stage switch elements connected in series between a neutral point and a second input end of the direct-current power supply and a second charging and discharging capacitor including a first end that is connected to a connection point between the fifth preceding-stage switch element and the sixth preceding-stage switch element and a second end that is connected to a connection point between the seventh preceding-stage switch element and the eighth preceding-stage switch; a bridge clamping circuit including first, second, third and fourth subsequent-stage switch elements bridge-connected to first, second, third and fourth terminals wherein a first end is connected to a connection point between the second preceding-stage switch element and the third preceding-stage switch element and a second end is connected to a connection point between the sixth preceding-stage switch element and the seventh preceding-stage switch element; a first inductor connected between a first output end and a connection point between the first subsequent-stage switch element and the second subsequent-stage switch element in the bridge clamping circuit; a second inductor connected between a second output end and a connection point between the third subsequent-stage switch element and the fourth subsequent-stage switch element in the bridge clamping circuit; a detection unit arranged to detect an output current and an output voltage of a single-phase three-wire power system having a U-phase and a W-phase; an amplification unit arranged to amplify a current error serving as an error of the output current with respect to a current target value of a substantially sinusoidal wave; a voltage correction value obtaining unit arranged to obtain a voltage correction value in a direction reducing the current error; a voltage target value obtaining unit arranged to obtain a voltage target value by superimposing the voltage correction value on a detection value of the output voltage; a PWM-modulation unit arranged to obtain a PWM-modulated signal of the voltage target value; a switch element drive unit arranged to drive the first, second, third and fourth preceding-stage switch elements and the fifth, sixth, seventh and eighth preceding-stage switch elements based on the PWM-modulated signal; and a switch unit arranged to switch a state of the bridge clamping circuit based on a sign of the voltage target value.