Design And Research On Control System For High Efficiency Brushless DC Motor

Water pump, which accounts for 20 percent of the country's electricity, is the main energy consumption equipment widely used in national production and life. With the increasingly serious energy crisis, improving the operation efficiency to reduce the energy consumption have actual value on targets for saving energy and reducing emissions in the nation's 12th Five-Year Plan.Taking the project"development and industrialization on new secondary water supply equipment"of Special Motor Institute of Shenyang University of Technology as the engineering background. BLDCM is used to drive pump, due to it has the advantages of simple control, convenient speed regulation and high efficiency. This dissertation researches on control system for high efficiency brushless dc motor, and efficiency optimization of control system is carried out to improve efficiency of controller and system. The main contents are as follows:Firstly, a controller of BLDCM whose rated power is 4.5kW and rated speed is 3000r/min is designed based on a special integrated chip MC33035 that has the advantages of low cost, simple control and easy realization. Peripheral hardware circuits are designed and improved. The designed controller is verified by experiments. System performance can achieve approximately the requirements of the project which are high efficiency and energy conservation.Secondly, the losses of BLDCM control system are analyzed and calculated. The efficiency optimization of BLDCM system is given from four aspects. They are switch frequency, PWM modulation mode, hall sensor's position and commutation advance angle. Through analysis and optimization, the optimum switching frequency, PWM modulation mode, position of hall element and commutation advance angle of BLDCM system are determined.Finally, a BLDCM control system is built using field programmable gate array (FPGA)to achieve the high efficiency BLDCM system at the base of the first controller. The hardware and the module circuit with HDL language are described in detail. Then experimental platform is set up to verify the controller of BLDCM. System performance can meet the expected requirements of the project which are high efficiency, energy conservation and good stability.