Research On Control Technology Of Brushless Dc Motor For Single Rotor Compressor In Inverter Air Conditioning

As people continue to pay attention to the energy-saving effect of air conditioners,major companies have also increased their investment in research on energy-saving air conditioners.The compressor is one of the most core components in the air conditioner,and its operating status directly affects the performance of the entire air conditioner.The compressor is also the most power-consuming component in the air conditioner.At present,most household inverter air conditioners use single-rotor compressors,and the internal drive motor part uses brushless DC motors.The control of air-conditioning compressors has become a hot topic in the air-conditioning industry.In this thesis,the sensorless position detection technology and speed fluctuation suppression of the brushless DC motor driving the single-rotor compressor of the inverter air conditioner are studied.The corresponding solution is proposed and the simulation and single-rotor compressor experiment are carried out.First of all,this thesis introduces the principle and structure of air conditioner and single-rotor compressor,and gives the structure,principle and mathematical model of the brushless DC motor driving the single-rotor compressor.Secondly,this thesis studies the rotor position detection of the compressor motor.Due to the structure of the motor in the compressor and the limitation of environmental conditions,the position sensor cannot be used.On this basis,it is proposed to build a virtual neutral point through circuit hardware and obtain the rotor position of the motor indirectly by using the inverse electromotive force zero crossing detection method.The three-stage starting strategy of single rotor compressor is studied,and the simulation model of single rotor compressor motor is built on Matlab/Simulink platform to verify the effectiveness of the rotor position detection method designed.In addition,this thesis analyzes the internal changes of the cylinder and the force of the rolling rotor during the operation of the single-rotor compressor,gives its load characteristics,and analyzes the reasons for the fluctuation of the rotational speed.In order to solve the fluctuation of the rotational speed,fuzzy control and PI Combining control,designing a fuzzy PI controller,building a brushless DC motor model of a singlerotor compressor through the Matlab/Simulink platform for verification,the results show that the fuzzy PI controller has better performance than the traditional PI controller,and can effectively suppress the single-rotor compressor Rotary compressor speed fluctuations.Finally,this thesis designs the hardware circuit and software of the single rotor compressor control system,and conducts experiments on a single rotor compressor with1.5P air conditioning.The experimental results show that in the speed range of 600 r/min to 3500 r/min,compared with the traditional PI control,the suppression effect of the compressor speed fluctuation under fuzzy PI control can reach 16.27% at the lowest level and 44.59% at the highest level,which verifies the design of the single-rotor compressor.The effectiveness of the machine control algorithm can effectively suppress the speed fluctuation of the compressor and make the single-rotor compressor run stably.