Development Of Brushless DC Motor Drive System For Hydrogen Circulation Pump

With the serious impact of fossil energy consumption on environmental pollution,the new energy vehicle has become a research hotspot.With many advantages such as zero emission in using,high energy conversion efficiency and low noise,hydrogen fuel cell vehicles have a broad development prospect.Hydrogen circulating pump is one of the important components in vehicle hydrogen fuel cell system.So it is of great significance to study the control technology of the hydrogen circulating pump drive motor.This thesis is based on a hydrogen fuel cell hydrogen circulating pump motor drive system development project.The main content of this thesis is divided into the following parts:The main research directions of brushless DC motor control technology in highspeed and sensorless control are introduced.Combined with the structure and working principle of brushless DC motors,the mathematical model of the motor is derived.According to the requirement of hydrogen fuel cell to the drive system of hydrogen circulating pump,the design scheme of the motor drive system of hydrogen circulating pump is determined.According to the design plan,the hardware circuit of the brushless DC motor controller is designed.Then the software program development of the controller was carried out.The generation principle and calculation method of power loss in the working process of MOSFET are discussed.The aluminum substrate heat sink for the control board is designed and the finite element simulation analysis is carried out.The simulation results show that the heat sink can meet the requirements.The experimental platform is built,the motor controller is debugged,and the hardware circuit is adjusted according to the debugging results.The system testing on the experimental platform verifies the effectiveness of the brushless DC motor drive system.The discussion of the sensorless control of the brushless DC motor was discussed,and an optimization method of back-EMF rotor position detection based on PWM duty cycle was proposed.According to the high and low level maintenance time corresponding to the different duty cycles during the chopping process,the sampled time is divided into small duty cycle time and the large duty ratio energized time,and a duty ratio threshold hysteresis sampling strategy is designed.The strategy gives a relatively accurate low frequency chopping time detection optimization calculation method.The experimental test shows the feasibility of the proposed detection method.