| 摘要 |
PROBLEM TO BE SOLVED: To provide a commutation method, for a cycloconverter, which does not required a snubber circuit or the like. SOLUTION: In a commutation method for a cycloconverter 5, when the polarity of the output voltage of a high-frequency link-type PWM inverter 1 is different from that of its output current, all semiconductor switches at the cycloconverter 5 in which the output current of the high-frequency link-type PWM inverter 1 can flow are set to an ON state in a period in which the voltage of a DC power supply is applied to the primary side of a high-frequency transformer 4, the primary-side voltage of the high-frequency transformer is applied to the leakage inductance on the secondary side of the high-frequency transformer, the current which flows in the semiconductor switch at the cycloconverter 5 which is set to continuity before the output polarity of a high- frequency inverter 3 is reduced, the current which flows in the semiconductor switch at the cycloconverter 5 which is to be set to continuity after the changeover the output polarity is increased, and the semiconductor switch is turned off when the current which flows in the semiconductor switch at the cycloconverter 5 which is set to continuity before the output polarity of the high-frequency inverter 3 is changed over becomes zero. |
