| 摘要 |
PURPOSE:To prevent the rush current into a transformer, when such a DC power as the ones of solar batteries or fuel cells whose output state is changed largely is converted into an AC power by an inverter and the output of the inverter which is insulated from the inverter by the transformer is interconnected to a power system, by making the breaker provided on the side of a power system when the interconnection condition is satisfied. CONSTITUTION:The output power of such a DC power supply 1 as a solar batteries and fuel cells whose variation is large is converted into an AC power by an inverter bridge 2, and the output power of the inverter bridge 2 is fed to an insulation transformer 6 via an inductor 3 and capacitor 4. Further, the output of a DC voltage sensor 10 and a power- system-voltage sensor 11 are inputted to an excitation-current-reference generator 24. Also, a current reference I2*sinwt associated with power factor equal to 1 and an excitation current reference I1*sin(wt-pi/2) of the transformer 6 which is sensed by a CT 12 are added to each other and are inputted to a current amplifier 22, and further, the output of the amplifier 22 is inputted to a PWM generator 23, and by the output of the PWM generator 23, the inverter bridge 2 is controlled. When an output voltage EV of the excitation-current-reference generator 24 and an output voltage VX of the power-system-voltage sensor 11 are confined within predetermined ranges respectively, a breaker driver 8 is turned on, and the inverter bridge 2 is operated so as to interconnected to a power system. Thereby, the rush current into the transformer 6 is prevented. |
