Synchronous motor driving circuit

Abstract

An embodiment of the invention provides a synchronous motor driving circuit. The synchronous motor driving circuit comprises a stator winding, a controllable bidirectional alternating current switch,an alternating current-direct current conversion circuit, a position sensor and a switch control circuit, wherein the stator winding and an external alternating current power supply are connected in series between a first node and a second node; the alternating current-direct current conversion circuit and the bidirectional alternating current switch are connected in parallel between the first node and the second node; the alternating current-direct current conversion circuit has no current flowing through due to short circuit between the first node and the second node when the controllable bidirectional alternating current switch is switched on; the position sensor is used for detecting the magnetic pole position of a permanent magnet rotor; and the switch control circuit is configured tocontrol the controllable bidirectional alternating current switch to be switched between a switch-on state and a cut-off state based on a predetermined mode according to the rotor magnetic pole position information detected by the position sensor and the polarity information of the external alternating current power supply so as to enable the stator winding to drag the rotor only in the startingdirection in the motor starting stage. By virtue of the synchronous motor driving circuit, the electric energy utilization rate can be highly improved.

Description

technical field [0001] The invention relates to a drive circuit of a permanent magnet synchronous motor, and is especially suitable for applications where the motor is used to drive low-power loads (such as low-power fans, water pumps, etc.). Background technique [0002] During the starting process of the synchronous motor, the electromagnet of the stator generates an alternating magnetic field, and drives the permanent magnet rotor to oscillate. If the rotor obtains enough kinetic energy, the oscillation amplitude of the rotor will continue to increase, and finally the rotation of the rotor will be accelerated rapidly to the point of contact with the stator. Alternating magnetic field synchronization. For traditional synchronous motors, in order to ensure starting, the starting point of the motor is usually set low, resulting in the motor not being able to run at the operating point, so the efficiency is low. On the other hand, due to the characteristics of alternating cu...

AI Technical Summary

Problems solved by technology

For traditional synchronous motors, in order to ensure starting, the starting point of the motor is usually set low, resulting in the motor not being able to run at the operating point, so the efficiency is low

On the other hand, due to the characteristics of alternating current and the non-fixed stop position of the permanent magnet rotor, it is impossible to guarantee that the rotor will rotate in the same direction every time it is started. Therefore, in applications such as fans and water pumps, the impellers driven by the rotor are usually straight. Radial blades, resulting in less efficient operation of fans, pumps, etc.

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