Patent ID: 6949899
Filing Date: 2005-09-27
Classification: H02P

Abstract:
1. A conversion circuit for a brushless dc motor connected with a dc motor drive circuit, comprising: a rectifier unit electrically connected to an ac power source to thereby supply a dc voltage to the dc motor drive circuit; a voltage-stabilizing control unit electrically connected between the rectifier unit and the dc motor drive circuit, and adapted to detect whether a dc voltage supplied by the rectifier unit to the dc motor drive circuit is a low dc voltage suitable for the brushless dc motor; and a voltage-stabilizing unit electrically connected between the voltage-stabilizing control unit and the dc motor drive circuit, said voltage-stabilizing unit being controlled by the voltage-stabilizing control unit to supply a stabilized dc voltage to the dc motor drive circuit only if the voltage-stabilizing control unit detects that the dc voltage supplied by the rectifier unit is said low dc voltage; wherein the dc voltage supplied from the rectifier unit is passed through the voltage-stabilizing control unit controlled by the voltage-stabilizing unit to turn on or off the dc motor drive circuit, said voltage-stabilizing control unit cutting off supply of dc voltage to the dc motor drive circuit when a high dc voltage is detected.