Position Sensorless Noise Reduction Control Of Dual Three-Phase Permanent Magnet Motor With Random Frequency Triangular Wave Injection

Dual three-phase permanent magnet motors have advantages such as high power density,high torque density,and strong fault tolerance performance,making them significantly advantageous in the field of ship propulsion.The high-frequency signal injection method is an effective zero low speed sensorless control method.It can improve the reliability of the dual three-phase permanent magnet motor control system.However,the injected high-frequency signal can cause serious audible noise problems and generate maximum noise at the injection frequency,which cannot meet the requirements of high-end applications such as ship propulsion.To achieve noise reduction,this paper focuses on dual three-phase permanent magnet motors and proposes a random frequency triangular wave injection method based on vector space decoupling.Two triangular wave voltage signals with different frequencies are randomly injected into the motor,reducing the maximum noise at the injection frequency,and expanding the power spectral density of high-frequency current,thus reducing high-frequency noise.In addition,to further reduce noise,a variable axis random frequency triangular wave injection method based on the dual dq model is also proposed.The random frequency triangular wave voltage signal is injected into the motor by randomly changing the axis system.The simulation and experimental results verify the feasibility and effectiveness of the proposed control strategy.The central substances of this paper are as follows:1.The mathematical model of a dual three-phase permanent magnet motor in a six-phase natural coordinate system is established.The mathematical model of dual three-phase permanent magnet motor in the two-phase stationary coordinate system and the synchronous rotating coordinate system is constructed.The basic principle and implementation method of position sensorless control using high-frequency signal injection method are described.2.A random frequency triangular wave injection method based on vector space decoupling is proposed to address the issues of maximum noise at the injection frequency and highfrequency noise at fixed frequency injection.The basic principle of random number generation is briefly described.The waveform form and position information demodulation strategy of the random frequency triangular wave injection method are introduced in detail.In addition,the power spectral density theory of the method is analyzed to reveal the noise reduction mechanism of the method.Finally,the random frequency triangular wave injection method is simulated,modelled,and analyzed using Matlab Simulink.3.In order to further reduce noise,a variable axis random frequency triangular wave injection method is proposed based on the dual dq model.For this injection method,a synthetic position information demodulation strategy is designed,and its power spectral density theory is analyzed.Finally,a simulation model is built using Matlab Simulink to verify the feasibility and effectiveness of this control strategy.4.A dual three-phase permanent magnet motor experimental platform using TMS320F28377 S as the main control chip is established,and the hardware and software implementation principles of this experimental platform are briefly introduced.The control strategy proposed in this paper is experimentally verified from the perspectives of power spectral density analysis,steady control performance analysis and dynamic control performance analysis.