| 摘要 |
PURPOSE: To prevent inverter operation from being interrupted by accident. CONSTITUTION: A series resonance inverter is constituted of a series resonance circuit, that can be connected to a DC power supply via at least two push-pull thyristors and a diode connected antiparallel with them, a zero-cross detector for generating a zero-cross signal as soon as current passing through the series resonance circuit exceeds a specific value after the zero crossing, and an excitation pulse generator that is controlled by the zero-cross detector, so that an excitation pulse for the thyistor is generated. Measurement apparatuses 702,..., 704 for measuring the time interval between the excitation pulse and the next zero-cross signal and a memory 705 for accumulating the time interval for normal operation are provided. Also when the measured time interval exceeds the accumulated time interval by a specific value or more, generation circuit 706,..., 709 for generating an auxiliary zero-cross signal are provided. |
