| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent erroneous overcurrent determination and protection operation by utilizing the power conversion performance of a power conversion device to the most. <P>SOLUTION: The overcurrent protective device supplies a controlled electric power/current to a load 2 by on/off control of a semiconductor switch element (IGBT) constituting a main circuit of an inverter 1, and protects the IGBT from overcurrent when a detection value of the current flowing the IGBT exceeds an overcurrent determination level for the IGBT at a current detector 6. An overcurrent determination level variable circuit 3A sets/adjusts an overcurrent determination level Ij to a higher value as a DC voltage Ed of the main circuit becomes lower. A comparator 3B, when determines that a detection current Idet has exceeded the overcurrent determination level Ij having been set/adjusted, cuts off the current to the load and IGBT by turning off the gate voltage output of a drive circuit 4. <P>COPYRIGHT: (C)2012,JPO&INPIT |
