Patent ID: 6211635
Filing Date: 2001-04-03
Classification: F04D,F05D,H02P,Y02B

Abstract:
A brushless motor driving system for driving an outdoor fan of an air conditioner comprising:a single Hall probe for detecting a position of a rotor of a brushless motor for driving the outdoor fan of the air conditioner;an inverter circuit consisting of six switching elements connected in a three-phase bridge connection, DC terminals of the inverter circuit being connected to a main DC power source, AC terminals of the inverter circuit being connected to star-connected stator coils of the brushless motor; andcontrol means for controlling the switching elements in the inverter circuit in synchronization with an output signal from the Hall probe so as to generate a predetermined magnetic field in a direction of braking a rotation of the rotor, the control means including DC excitation means, whereinbefore starting the brushless motor, said DC excitation means controls one switching element of one phase of a positive or negative side of said inverter circuit and switching elements of the other two phases of the other side to supply a pulse width modulation (PWM) controlled DC current to the stator coils of the motor, thereby bringing the rotor to brake and stop at a first position.