A method for starting a brushless DC excitation synchronous motor

Abstract

The invention discloses a starting method of a brushless DC excitation synchronous motor, including S1, an asynchronous starting closed-loop vector control process: according to the three-phase stator currents Ia, Ib and Ic of the synchronous motor, three-phase reference voltages Va, Vb, Vc are obtained, Output to the stator winding of the synchronous motor for excitation through PWM modulation; S2, transitional closed-loop vector control process: when the speed of the synchronous motor reaches the preset speed, the excitation of the stator winding is gradually switched to the excitation of the brushless DC excitation device; S3, synchronous Closed-loop control process: When switching to all the excitation provided by the brushless DC excitation device, the synchronous motor enters the synchronous operation process. The starting method of the brushless DC excitation synchronous motor of the present invention has the advantages of simple control, reduced starting current, excellent speed regulation performance and high starting torque.

Description

technical field [0001] The invention mainly relates to the technical field of motor control, in particular to a starting method of a brushless DC excitation synchronous motor. Background technique [0002] Because there are no brushes and collector rings, the brushless synchronous motor avoids the generation of sparks, simplifies the operation and maintenance procedures, and reduces the damage of brush dust to the motor insulation. Wide range of applications. At the same time, due to the removal of vulnerable components such as carbon brushes, the overall reliability of the motor is greatly improved, and there are many applications in some occasions that require continuous long-term high-reliability operation. [0003] The structure principle of brushless DC excitation synchronous motor and excitation system is as follows: figure 1 As shown, the main difference between it and the ordinary brushed synchronous motor is the excitation system. The brushless DC excitation syste...

AI Technical Summary

Problems solved by technology

The starting method mentioned in the papers "Application of High Voltage Frequency Converter to Increased Safety Brushless Excitation Synchronous Motor" and "Research on Variable Frequency Operation Mode of Brushless Synchronous Motor" can reduce the starting current, but the open loop method is difficult to achieve better The control effect of the motor is not strong, and the load capacity of the motor is not strong; at the same time, the motor speed fluctuates greatly during the whole step of excitation, which may easily cause the inverter to over-current or the module to trip due to over-voltage, and the starting success rate is not high

The synchronous motor involved in the patent "Starting Control Method and Device of Aeronautical Three-Stage Electric Excitation Synchronous Motor" is quite different from the ordinary brushless synchronous motor. Said control method is also different from the present invention

Because the brushless DC excitation synchronous motor can only be started asynchronously, the closed-loop vector control or torque control strategy of ordinary brushed synchronous motors cannot be directly used

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