| 摘要 |
PROBLEM TO BE SOLVED: To supply electric power with less voltage fluctuation without interrupting the power system voltage, by supplying a sinusoidal drive control signal of fixed amplitude synchronizing with the power system voltage to a correction circuit block, and controlling the output voltage of an inverter with the drive control signal through a correction circuit block. SOLUTION: A drive control part 10 of an inverter 4 is provided with a main control block 11, and a sinusoidal correction block 12 which corrects the amplitude of the drive control signal for driving the inverter 4 of fixed amplitude outputted by the sinusoidal circuit 9 of the block 11. The output voltage of the inverter 4 phase-synchronizes with the system voltage, and is corrected so as to follow the system voltage when the system power source 1 is normal and is controlled so as to be the lower limit of the system voltage when the system power source 1 is in a power failure condition, by a closed loop control through the correction circuit block 12. It is thus possible to keep inverter voltage at the system voltage without having an adverse effect if a load change occurs, thereby supplying stable electric power to the load 3. |
