| 摘要 |
PROBLEM TO BE SOLVED: To attain stable control even at a transitional decrease of input AC voltage by detecting an AC power supply voltage and changing a voltage command value with an AC voltage in the ignition phase control of the switching element of an inverter for converting the DC voltage of a rectifying circuit into constant an AC voltage. SOLUTION: The output of a rectifier 13 which rectifies an AC voltage e1 from a voltage sensor 11 is smoothed by a smoothing circuit 14, a prescribed gain K (0<K<1) is multiplied by a multiplying circuit 15. Deviation between a voltage command value V* produced by a voltage command control circuit 16 and the voltage V2 of a smoothing capacitor is computed by a subtracter 8, output voltage Vref is produced by a voltage controller 9 which includes an integral element. A phase signal is outputted by a phase control circuit 10 from a carrier wave produced, based on the AC voltage e1 of the voltage sensor 11 and the voltage Vref, and the gate signal is produced, to be transmitted to the thyrisor element of a rectifying circuit 2. Conseguently, by ensuring a fixed amount of control marginal angle, it is possible to advance ignition phase at transitional dive of the AC voltage, thereby attaining stable control. |
