Research On The Energy-saving Method Of Brushless DC Motor

With the development of electronic technology, brushless DC motor came into being,and it is the product of modern electronic technology combined with motor technology.Electronic commutation is applied to the brushless DC motor to replace the original mechanical commutation, which increases the life expectancy, reliability, speed performance,high efficiency, small size, etc., and it is widely used in industrial control and daily life.Although the superior performance and the wide scope of application of brushless DC motor,but in advocating environmental protection, energy conservation and emission reduction, the problems of energy saving motor become the focus of scholars, which has important significance.Firstly, the development status and research significance of the brushless DC motor are introduced, and its body structure, mathematical model, operating principle and control method of the hot spot research is realized, and the importance of energy saving of brushless DC motor is cleared.Secondly, an advanced control technique based on a linear tracking method the current waveform track the induced EMF waveform is presented, for energy saving of the brushless DC. The product of each voltage and current harmonic produces electrical output power. So,we have to consider all the harmonics included when calculating output power. For maximum power, each voltage and current harmonic should be in phase, and using the zero sequence elimination method to obtain the back EMF except zero sequence components. Then combined with theoretical analysis, the effectiveness of the proposed control strategy is demonstrated through the Matlab/simulink platform.Finally, brushless DC motor energy saving control system based on the current waveform track the induced EMF waveform is designed, in which speed loop and current loop are designed, regards the output signal of speed loop PI regulator as the input signal of current loop PI regulator, and considers the signal current loop PI regulator output signal as the PWM signal. The motor position signal which is obtained by the Hall sensor is sampled through the FPGA port, after the processing, obtains the commutation signals, reverses motor control, and calculates the motor speed. The current signal is obtained by the current sensor,through the samples of AD passed to FPGA port. At the same time, the processed bus voltage signal is sent to the FPGA chip, and protects the entire system from over voltage. In addition,the system also sets the terminal voltage detection module which is used to calculate commutation interval, overloads PWM duty ratio which derived from the non-commutation phase terminal voltage remained constant before and after the process of commutation, and compensates the terminal voltage during commutation to reduce torque ripple. Through debugged, the BLDCM is in stabilization work state, and achieves the desired effect.