Research On Motor Drive Control System For Mining In High Temperature Environment

As the core unit of driving motor,motor drive control system is widely used in mineral resources exploration and other fields(such as underground pipe electric cutting,belt transportation,ventilation,etc.).Mining motor usually works in extreme environments such as high temperature and high pressure for a long time,which requires its control system to have high accuracy,reliability and stability.In this paper,taking the motor drive system of mining downhole cutting equipment as the research object,a permanent magnet synchronous machine(PMSM)drive control system is designed to solve the problems of unstable output signal of grid driver and nonlinear change of bus capacitance under high temperature environment.The drive system mainly improves the design of the high temperature special function circuit based on the position No position sensor control system based on the Extended Kalman Filter(EKF)and the grid driven IC,which improves the high temperature adaptability and control accuracy of the ystem.The main research contents are as follows:Firstly,the mathematical models of PMSM in different coordinates are established.The development of mine motor drive control system and modern PMSM control strategy are analyzed.The theoretical analysis of coordinate transformation of three-phase PMSM,the design of space vector pulse width modulation and closed-loop control regulator are completed.Secondly,the high temperature adaptability of sensor less system based on improved EKF is studied.(1)By selecting the No position sensor control strategy,the connection line between the inverter and the motor is simplified,and the reliability of the system is improved;(2)By enhancing the fundamental wave signal,the pulse high-frequency signal is injected into the d-axis of the synchronous rotating coordinate system,so that the superimposed fundamental wave signal is applied to the three-phase winding together,and then the voltage signal output by EKF is extracted and amplitude modulated by a bandpass filter to estimate the rotor position;(3)Finally,the drive system is simulated with MATLAB/Simulink.The results show that the filtering gain effect of the improved EKF non inductive control system is good,which can significantly improve the control accuracy of the drive system at high temperatures and improve the low signal-to-noise ratio of the rotor useful signal at low speeds.Thirdly,the hardware and software of the system are designed.The failure mechanism of the main electronic components is analyzed,the components are selected,and the circuit design with TMS320F28035 PNQ digital signal processor as the core is completed.In order to reduce the system power consumption and improve the high temperature adaptability of the drive part,the grid drive IC is designed with a special high temperature functional circuit starting from the smallest controllable integrated unit.The bus capacitance shall be replaced,the thermal insulation between boards and the aluminum base shell shall be achieved,and the PCB routing layout shall be optimized.At the same time,the software program flow is designed to realize the basic functions of the controller.Finally,an experimental platform is set up to verify the high-temperature adaptability of the motor drive controller.The experimental results show that the system has good adaptability and control performance in high temperature environment.The system can run stably at 125℃ for more than two hours,and the communication is normal.The useful signal-to-noise ratio of rotor position signal is increased by about 47.62% at zero speed and extremely low speed,and the phase difference of three-phase alternating current is complementary by 120,reaching a balanced and stable state.