Research On Position Sensorless Control System Of Permanent Magnet Synchronous Motor For Blower

With the booming of the automotive industry,requirements for various performances of automobiles have increased.As an important part of the car’s cooling system,the vehicle cooling blower has an important impact on the safety and comfort of the car.High requirements represent high control performance,and cooling blowers are also moving toward low noise,high efficiency,low cost,and small size.The conventional PMSM control strategy relies on the rotor position sensor,but at the same time increases the system cost and is susceptible to external factors such as the environment.In order to reduce the cost,improve reliability,continue to reduce the size of the motor and have good control performance,the position sensorless control algorithm of PMSM for blower has become one of the research hotspots of the blower bottom drive algorithm.In this paper,the position sensorless control strategy of PMSM for blower is studied.The combination of low speed IF control and medium and high speed back-EMF integration method is adopted.The hardware is designed by stm32F103C8T6 as the main control CPU and the control program is designed.Finally complete the experiment debugging work.The low-speed and medium-high-speed state switching process is analyzed.On the_qi^（9）current regulator,the state switching performance under different current decreasing slopes is compared.The distortion of the air gap magnetic field causes the motor phase current to be distorted and contains many higher harmonics.The direct voltage compensation method and the current loop harmonic suppression method are introduced to eliminate the higher harmonics contained in the phase current.For the5th harmonic,the direct voltage compensation method uses the 5th harmonic component of the three-phase stationary coordinate system to represent the 6th harmonic in the fundamental dq synchronous rotating coordinate system.Injecting the corresponding 6th harmonic voltage into theu_dandu_qcontaining the harmonic component can eliminate the5th harmonic component contained in the back EMF.The current loop harmonic suppression method is divided into three steps:harmonic current extraction,harmonic voltage calculation,and harmonic voltage injection.The 5th harmonic current is expressed as a direct current in the5th dq-axis synchronous rotating coordinate system rotating at 5?,and the fundamental current is expressed as an alternating current.The 5th harmonic current can be extracted by the low-pass filter,and then the 5th harmonic voltage is obtained by the PID adjustment and is transformed into the two-phase stationary coordinate system by the inverse Park and then superimposed with the fundamental wave.Combined with the characteristics of the blower,the starting performance and running stability of the position sensorless fan under the upwind condition are studied.The idea of starting the blower under the reverse wind reverse condition is given,so as to accelerate the stable opening of the blower.The experimental results show that the designed sensorless PMSM for blower control system has strong robustness,good blower running stability,and can adapt to the starting and acceleration under different working conditions,which has great application value.