SYNCHRONOUS MOTOR DRIVE CIRCUIT, SYNCHRONOUS MOTOR DRIVEN BY SAME, FAN USING THIS SYNCHRONOUS MOTOR, AIR CONDITIONER USING THIS FAN, AND SYNCHRONOUS MOTOR DRIVING METHOD

摘要

The objective of the present invention is to provide a drive circuit for a synchronous motor which is highly efficient and is able to suppress vibration/noise due to electromagnetic excitation force in the radial direction when the motor is driven by a rectangular wave driving method, and to provide a synchronous motor driven by this drive circuit, a fan using this synchronous motor, an air conditioner using this fan, and a synchronous motor driving method. The drive circuit (100) is for a synchronous motor equipped with a rotor (4) having ten magnetic poles formed by permanent magnets (6), and a stator (1) wherein windings (3) are wound in a concentrated winding around nine teeth (2) facing the rotor (4). The drive circuit is equipped with an inverter (200) formed by bridge-connecting multiple switching elements (201a-201f), and a control means (300) that controls the inverter (200) so as to energize the windings (3) with a rectangular-wave current. The energization phase of the rectangular-wave current operates in an electrical angle ranging from −10° to +5° with respect to the energization phase that results in the minimum current when the target torque for the synchronous motor is generated.