| 摘要 |
PROBLEM TO BE SOLVED: To ensure smooth start up even in case of simultaneous stare up by employing a simultaneous chopping system, when an operation is started and making a switch to single chopping system during the operation. SOLUTION: This brusless motor comprises an inverter, having a series connection of semiconductor switches Qu+ and Qu-, Qv+ and Qv-, and Qw+ and Qw-, and when a commercial power supply AC is turned on, a DC voltage is induced in a smoothing capacitor C1 and applied to an inverter. A position detecting circuit PSC detects the position of a permanent magnet rotor Rt and, based on the detected signal, a control circuit CC turns the semiconductor switches Qu+, Qu-, Qv+, Qv-, Qw+, Qw- on/off thus rotating the rotor Rt. At simultaneous start up, switching elements in the upper arm of some phase and in the lower arm of other phases are chopped simultaneously. At brushless motor operation, only one of there switching elements is chopped. According to the arrangement, circulation current will be suppressed, even at simultaneous start up, and smooth start up is ensured. |
