| 摘要 |
PURPOSE: To obtain a power conversion apparatus which can be operated stably even when an overload capacity is very large or a large overload is changed suddenly. CONSTITUTION: In a power conversion apparatus, switching energy in GTO thyristors S1, S2 is collected once by a regenerative capacitor CC1, and the energy is regenerated to a main DC power supply Ed via chopper circuits (SC1, SC2, DC1, DC2). In the power conversion apparatus, a voltage in the regenerative capacitor CC1 whose voltage is controlled by the chopper circuits after the level of a main circuit current has been detected by a load-current level discriminator LD changes a regenerative-voltage reference value to REF2 from REF1 by a changeover device CH when the level of the main circuit current is at a prescribed value or higher. Thereby, a chopper voltage reference REFC is lowered, and the continuity period the GTO thyristors for the chopper circuits is controlled by a chopper voltage reference REFC via the lowered chopper voltage reference REFC so as to be controlled to a low voltage. |
