Research On Fan Motor Controller

The frequency conversion regulating velocity technology for fan is an importanttechnology of solving the energy problem and economic benefit problem faced in thefield of fan. In order to achieve the function of frequency conversion regulatingvelocity of the fan, it is necessary to focus on better research and development of thefan motor controller. The development of the fan motor controller has become a hottopic of research in the field of fan over the world. As it has the superiority of DCmotor speed control performance, permanent magnet synchronous motor (PMSM) hasbeen widely used in the field of fan, so this thesis focused on motor controller of fanwith PMSM.At present the industrial grade motor controller mainly uses the field orientedcontrol (FOC) strategy, using the current sensors to collect three-phase current of themotor, through the installation position sensor in the motor to obtain the motoroperating angle. But the high cost of this motor controller go against its popularizationin the fields of fan, so more fan motor controllers use three sampling resistor toreplace current sensor, use the state observation method which can estimate angle toreplace position sensor. The innovation of this thesis is adopting single resistorsampling techniques in the current collection. This technique can save moreproduction cost.Starting with equivalent voltage equation of PMSM, this thesis analyzes the roleof direct-axis and cross-axis armature reaction, and the characteristics of thepower-angle and torque-angle. Through using of the vector coordinate transformation,we establish a dynamic mathematical model of PMSM in the rotor magnetic fieldcoordinates to achieve the FOC.This thesis designs the hardware circuit of the master control module, theintelligent power module, the rectifier module, the power module, the communicationmodule and the data storage module. In order to improve the safety performance, wealso design over-current, short circuit and under-voltage fault detection circuit.Through concrete analyze the problems of single resistance sampling technologywhich combined with space vector pulse width modulation (SVPWM) technology, wedevelop solutions and software implement strategy. Through using of the software compiler, we design the overall control strategy and software program flow of the fanmotor controller, also modify and streamline the program code by online debugging.Through setting up the fan motor controller test platform, we test the samplingaccuracy and stability of single resistance sampling system, the result shows that itssampling window enough, sample point position accurate, the three-phase currentcurve close to sine after reconstruction. Through practical operation of the fan in realtime monitoring and testing, the results show that the closed-loop switching smoothlyand good performance of speed regulation.