Research And Application Of Phase-Current Reconstruction Technology In Vector Control System Of Inverter Compressor

Nowadays,Application of frequency conversion technology on refrigerator compressor technology is the main bottleneck of Chinese refrigerator industry.In all kinds of frequency conversion driving technologies,Permanent Magnet Synchronous Motors(PMSM)frequency conversion driving technology has splendid speed-regulation performance and excellent energy-saving performance.Therefore the vector frequency conversion technology which applies on inverter refrigerating compressor adopted senseless Permanent Magnet Synchronous Motors(PMSM)has been the hot area of research.This paper made deep research and experimental study on phase-current reconstruction and rotor position measurement in senseless vector frequency conversion technology,used STM32F103produced by ST company as the main control core,the method of reconstructing three-phase current using only a single-resistor in the inverter dc link and the sliding mode observer to detecting continuous position is adopted,the refrigerator compressor vector frequency conversion control is realized.The following aspects in this dissertation were analyzed:1.According to basic structure of Permanent Magnet Synchronous Motors(PMSM),mathematical model in different coordinate system and conversion method.control algorithm of senseless Permanent Magnet Synchronous Motors(PMSM)Field-Orientation Vector Control,the Space-Vector Pulse Width Modulation(SVPWM),reconstructing three-phase current using only a singe-resistor and Sliding Mode Control arithmetic is detailed analyzed.2.The method of reconstructing three-phase current using only a singe-resistor is adopted.In the Space-Vector Pulse Width Modulation(SVPWM)inventor driving system,sampling the DC bus instant current using only a single-resistor reconstruct three-phase current.And a mathematical method of using predictive state observer to the non-observable regions in the process of space vector pulse width modulation.3.The speed and position of compressor can be estimated by using speed control arithmetic based on Sliding Mode Observer and PI control was taken to control the speed.Influence of refrigerating compressor's COP,noise and oscillation was studied from two aspects which were PWM modulation frequency and speed of motor.4.Based on the above theoretical analysis,hardware circuit and the corresponding PCB of the drive system was designed;also the method of general control software was built.Finally,two experimental platforms were built in order to debug and tested the system function and refrigeration performance.The experiment results indicated that the system had steady and splendid speed-regulation performance;refrigerating compressor's COP was improved.Thus,it achieved the anticipated effect.