| 摘要 |
PROBLEM TO BE SOLVED: To increase the fundamental wave constituent of an output voltage with a simple control circuit by obtaining a median value except the maximum and minimum values by a comparator, providing an adder for adding a value where the median value is divided by 2 to each voltage command, and newly setting the output of the adder to the voltage command value. SOLUTION: A voltage command comparison means 6 compares the magnitude of three-phase instantaneous voltage commands 501-503 that are generated by a voltage command means 5 to one another and outputs a median value excluding a maximum value 601 and a minimum value 602 from them. The half of a median value 603 of a voltage command is used as a voltage command correction signal 605, and values obtained by adding it to the voltage commands 501-503 of each phase are used as new voltage commands 606-608. A carrier 701 outputted by a carrier generation means 7 is compared with new voltage commands 606-608 of each phase by comparators 8a-8c, respectively, and obtained signals are used as a pulse width modulation signal, thus turning on or off each switching element of an inverter 3 through drive circuits 9a-9f. |
