| In the refrigeration industry,my country is the world’s largest manufacturing country,and it is also the first consumer market for refrigeration products.With the active advocacy and support of national policies,the energy-saving space in the refrigeration industry is huge.As the core of the refrigeration system,the compressor is the key to the energy-saving control of the refrigeration system.It has become a trend for compressors to be driven by permanent magnet synchronous motors in recent years,but the traditional classic control algorithm has not fully exploited the advantages of permanent magnet synchronous motors.With the advancement of power electronics technology,the continuous enhancement of microcontroller chip processing capabilities and the implementation of complex algorithms on the drive system can significantly reduce the energy consumption of the compressor.Therefore,the development of high-performance compressor drive systems has important economic and social value.Starting from the structure and working principle of the permanent magnet synchronous motor,the thesis discusses the advantages and disadvantages of each structure motor.Among them,the built-in permanent magnet synchronous motor has excellent power density and overload capacity.Through the mathematical transformation matrix,the mathematical model of the PMSM in the three-phase natural coordinate system is transformed to the mathematical model in the rotating coordinate system,so that the vector control can be realized;the control of the MTPA is determined by analyzing the different control algorithms of the vector control technology.Method:Discussed the principle of sensorless control,determined the sensorless technology based on the position estimation of the state observer;then discussed the technical principle of SVPWM;By discussing the working principle of the refrigeration system,the characteristics of the torque and speed of the compressor are analyzed,and the proportional relationship between the refrigeration capacity of the compressor and the speed is demonstrated.It is determined that the compressor speed is used as the control variable,and a double fuzzy controller is designed to correct the parameters of the PI controller.Finally,the system is simulated by MATLAB software,and the conditions of double fuzzy,single fuzzy and no fuzzy are compared.The results show that the dual fuzzy controller can effectively suppress the torque fluctuation and speed fluctuation of the PMSM,and the start-up time is shortened by 32%compared with the single fuzzy controller.After comparing the power situation of i_d=0 control and MPTA at the same speed and load,the simulation results showed that the stator winding phase current amplitude of the motor decreased by about 7.96%compared with i_d=0,and the power factor of the system increased from 0.86 to 0.97.The thesis takes the STM32 control chip as the core of the drive system,and designs hardware and software around it.In terms of hardware design,the peripheral circuit design of the microcontroller is carried out,and then the power supply circuit,signal acquisition circuit,power supply circuit,communication circuit,and IGBT power module are carried out.And power supply control circuit,IGBT drive circuit design.In terms of software design,the main software program was first designed,and then the safety task program,state processing program,motor driver program,communication program,etc.were designed on this basis.At the same time,the upper computer interface was designed using the graphical programming interface,and Conducted experimental debugging.Experimental results in different experimental environments show that,compared with not using fuzzy algorithms,the use of dual fuzzy control algorithms in the compressor drive system has significantly improved its energy-saving effect,which proves the superiority of the system design. |
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