Research On Harmonic Excitation Control System Of Brushless Hybrid Excitation Generator

Hybrid excitation synchronous motor combines the respective advantages of permanent magnet motor and electric excitation motor,and effectively solves the problems of inconvenient excitation adjustment of permanent magnet motor and low efficiency of electric excitation motor,and has broad application prospects.Taking a brushless hybrid excitation generator with additional harmonic winding as an object,the research is carried out around its harmonic excitation control system,and the adjustment of the terminal voltage of the hybrid excitation generator with different loads is realized.The working principle of the hybrid excitation synchronous generator with additional harmonic winding is analyzed,and the mathematical expression between the rotor excitation current and the stator harmonic excitation current is obtained;the stator harmonic excitation current can be DC current or AC current,by controlling the The current can realize the adjustment of the air gap magnetic field and terminal voltage of the motor.At the same time,according to the structure and working principle of the generator,the mathematical model of the hybrid excitation synchronous generator is established.A DC excitation control system based on phase-shifted full-bridge converter topology is designed.The system adopts a double closed-loop control strategy,the armature winding line voltage is used as the control outer loop,and the stator harmonic excitation winding current is the control inner loop.By adjusting the DC current input into the stator harmonic excitation winding,the constant voltage of the generator is realized.run.The structural block diagram of the DC excitation control system is given,the design of the DC excitation main circuit and the calculation of circuit parameters are completed,the hardware platform of the DC excitation control system with DSP28335 as the core controller is built,and the system is designed according to the DC excitation control strategy The software program establishes a complete set of DC excitation control system.In order to improve the harmonic excitation power of the hybrid excitation generator,on the basis of the DC excitation control system,a set of AC excitation control system was developed,including the simulation analysis of the double closed-loop control strategy and the design of the software and hardware of the excitation system,providing the stator harmonic excitation winding AC current,the additional harmonic magnetic field generated by it can be decomposed into two rotating magnetic fields.In the case of the same number of turns of the rotor harmonic winding,a larger harmonic electromotive force and harmonic excitation power can be obtained.Based on the developed hybrid excitation synchronous generator prototype,a harmonic excitation control system test platform was built to test the performance of the developed DC and AC excitation control systems.The test results show that the harmonic excitation control system can automatically adjust the stator harmonic excitation current,effectively control the rotor harmonic winding electromotive force,excitation current,and air gap magnetic field,and realize the constant voltage operation of the generator under different loads.