Technology In Inverter Air-Conditioner Compressor

In the current household appliances market,especially in the air-conditioning product market with relatively high electricity consumption,the demand for energy saving and comfort of users is getting higher and higher,the market share of variable frequency air-conditioning is getting higher and higher,the energy efficiency standard of air-conditioning is also increasing year by year,and the cost pressure of air-conditioning is increasing.Compressors with high cost share have become the first object of cost reduction research.From scroll compressor to double-rotor compressor,more and more products adopt single-rotor compressor with lower cost.However,the frequency fluctuation and instability of single-rotor compressor in low-frequency operation has been plagued by the industry.At present,brushless permanent magnet synchronous motor(PMSM)is mainly used in variable frequency compressor for air conditioning.Therefore,this paper mainly studies the control technology of PMSM in low speed section,aiming at improving the control effect of compressor in low speed operation stage,ensuring stable,low vibration,power saving operation at low speed,and extending the range of low speed.In addition,as the current detection technology is an important part of the compressor drive technology center,this paper introduces a low-cost single resistance current detection technology,and proposes a solution to a problem in single resistance detection..This paper mainly analyses from the following aspects:In the first chapter,the research status and development trends at home and abroad are analyzed.The steady-state characteristics of permanent magnet synchronous motor are analyzed,and the conditions to ensure the stable operation of the motor are studied.In the second chapter,the control theory of brushless permanent magnet synchronous motor is introduced.Based on its working principle and steady-state characteristics,the causes of synchronous motor vibration are analyzed,and the vector control technology of synchronous motor is introduced.In Chapter 3,aiming at the adverse effects of the fluctuation of brushless permanent magnet synchronous motor(BLDPMSM)caused by load fluctuation on the system at low speed,a scheme of load fluctuation compensation(Id-PLUS)is proposed.The purpose of this scheme is that when the compressor works at low speed,the impact of load fluctuation on the stable operation of the motor becomes greater and it is easy to leave the stable region.It causes vibration distance and even stops running out of step.Using Id-PLUS control scheme,a compensation current is added to the reference current of the d-axis.By compensating the current component on the q-axis and changing the load angle,the motor runs in the stable region.In this part,the scheme is discussed in detail and verified by experiments.The effectiveness of Id-PLUS control scheme is verified by testing the actual air-conditioning products.The fourth chapter introduces the single resistance current detection technology,and puts forward the corresponding solutions to the existing problems.Finally summarizes the research results of this article,and the future research direction of this article related technique is prospected.