| 摘要 |
PROBLEM TO BE SOLVED: To provide an uninterruptible power source system, capable of supplying a stable power, even if an inverter and an external AC power source are switched and connected to a load. SOLUTION: When a commercial power source is interrupted, the terminated phase of the output waveform of the power source is detected, and the polarity of a pulse first output from an inverter 16 is decided based on the phase. That is, when the terminated phase of the output waveform of the power source is 0 to 90 degrees or 180 to 270 degrees with the phase of a zero-crossing point to be switched from a negative polarity to a positive polarity of the output waveform of the power source set as 0 degree. That is, when power interruption occurs in the phase in front of a half wave of the positive polarity or the negative polarity arrives at a peak, it is decided so that the pulse of the same polarity as the polarity of the terminated polarity of the output waveform of the power source is output to the inverter 16. |
