A control device and method for an AC excitation synchronous motor

Abstract

The invention provides an alternating-current excitation synchronous machine control device and method, and belongs to the field of electromechanical control engineering. According to the method, alternating-current excitation is conducted on a wound-type motor rotor winding through a variable-frequency controller, excitation efficiency is improved by controlling the excitation current of the motor through a rotor, the capacity of the system is decreased to be twenty percent or lower that of the motor, the capacity of the variable-frequency controller is greatly decreased, and device cost is greatly reduced. Active power of the motor running is provided by a stator winding through a power grid, the power factor on the stator side can be controlled to be 1, the speed regulation system is made more reasonable and more efficient through excitation control, and four-quadrant operation is achieved.

Description

technical field [0001] The invention belongs to the field of electromechanical control engineering, and in particular relates to an AC excitation synchronous motor control device and method. Background technique [0002] The existing frequency conversion speed regulation system basically uses the frequency converter to act on the stator end of the AC motor, not only to provide the active current for the motor to run, but also to provide the excitation current to maintain the magnetic field, so the capacity of the frequency converter must be greater than or equal to the capacity of the motor. First, the capacity selection, withstand voltage and current rating of all components such as switching tubes, capacitors, reactors, and even wires used in the inverter must be large enough to match the motor, especially in some megawatt systems The series connection of a large number of switching devices is required to realize the control of the motor, resulting in high cost of the freq...

AI Technical Summary

Problems solved by technology

[0002] The existing frequency conversion speed regulation system basically uses the frequency converter to act on the stator end of the AC motor, not only to provide the active current for the motor to run, but also to provide the excitation current to maintain the magnetic field, so the capacity of the frequency converter must be greater than or equal to the capacity of the motor. First, the capacity selection, withstand voltage and current rating of all components such as switching tubes, capacitors, reactors, and even wires used in the inverter must be large enough to match the motor, especially in some megawatt systems A large number of switching devices need to be connected in series to realize the control of the motor, resulting in a high cost of the inverter

The excitation efficiency of the existing AC asynchronous motor is too low, which wastes energy; the AC synchronous motor requires an independent excitation unit or an expensive permanent magnet, which greatly increases the cost of the system

Images