Optimization Of Startup Performance And Vibration Noise Control For Air Conditioning Rolling Piston Compressor

Inverter air-conditioner has energy saving and comfort characteristics, the popularization and performance improvement of inverter air-conditioner has important meanings to energy saving and environmentalism to our country. The rolling piston compressors are adopted in mostly air conditioning systems now, the rolling piston compressor has lower parts, small size, lower vibration and noise excellences. Application of drive technology and improvement of vibration and noise reduction technology have important meaning to performance improvement of air conditioning system. Air conditioner compressor motor is located in close shell, inside space is narrow and is filled with high temperature and strong corrupt liquid, is unfit for installation of position sensor, usually sensorless drive method is adopted in air conditioning system. This paper studied sensorless drive technology of permanent magnet synchronous machines (PMSM) used in rolling piston compressors. To improve vibration and noise performance of compressor, this paper studied air conditioning compressor vibration and noise.Firstly on the base of reading literature characteristics and development status of inverter air-conditioner are introduced. Inverter air-conditioner is relate to refrigeration theory, thermodynamics, motor drive technique, electric power electronical technique, micro-electronics technique and autocontrol theory, hydrodynamics, mechanism design and noise theory. PMSM structure, PMSM sensorless drive, PMSM vector control and direct torque control are introduced in this paper. Rolling piston compressor structure and characteristics are discussed detailedly. Rolling piston compressor excellence, history and national development status and international development status, important performance guideline are introduced. The main problems of rolling piston compressor at present, the main content of this paper and the problems need solved and some key technical points are talked about.Secondly PMSM sensorless drive method is introduced detailedly, includes vector control strategy and direct torque control strategy. Sensorless drive arithmetics usually used at present are introduced, these methods include Extended Kalman Filter method, direct compute method, model reference adaptive system (MRAS) method and method based on observer. Drive performance of Extended Kalman Filter method and method based on observer are compared and researched through simulation. Direct torque control method is talked about. Simulation arithmetic adopts vector control system. id=0 strategy and MTPA strategy are talked about through simulation. Simulation results indicate that MTPA strategy has faster speed response performance compared with id=0 strategy to PMSM Ld is unequal to Lq.On the base of upwards discussion of sensorless drive arithmetics structure characteristic of rolling piston compressor is analyzed detailedly. Load simulation model of rolling piston compressor in working status is established. Load simulation model is combined with PMSM model to establish simulation model of rolling piston compressor in different working state. Speed and position response curves of compressor sensorless drive are presented. Because sensorless drive methods mainly adopted method based on observer at present, these methods have well drive performance at middle and high speed but drive performance is poor at standstill state or low speed, the process of compressor from standstill to middle speed require particular operation, this process is startup process of compressor. A simpler start method is proposed on the base of analyzing other start methods and combining with DSP characteristics and the experiment system is established. The start interval is decreased, reliability is improved and compressor can start successfully under samll pressure difference through theoretical analyse and experiment study. The acceleration curve of start process is optimized through repeating experiments. The feasibility and superiority of the start method proposed in this paper are validated through compare of experiment results.Next compressor sensorless drive methods are studied detailedly on the base of realization of compressor statup process. A sensorless drive arithmetic is selected and applied on compressor drive through analyzation of different sensorless drive arithmetics. Vibration and noise performance is an important performance to refrigeration compressors. Reasons of compressor vibration and noise is complicated. Now reduction of compressor vibration and noise method are improvement of shell design, installation of muffler. But the improvement of compressor drive effect to reduce compressor vibration and noise need not modification of hardware system, need not additional hardware and cost. To improve compressor vibration and noise performance the method through improving compressor drive effect is adopted. Compressor speed ripples is decreased through controlling torque side, speed side or changing sampling time, when different drive strategies are adopted compressor speed ripple is different, and these conclusion are proved through simulation experiments. The compressor vibration and noise performance is tested when different drive arithmetics are adopted in this paper. Different drive arithmetics have distinct influence to compressor vibration and noise performance is proved through compressor vibration and noise test in silencer room.Lastly manners and methods are concluded through compare and analyzation of experiment results. Different sensorless drive methods have different vibration and noise performance can be explained as below, different chips have different electric performance and different sampling time, different drive arithmetics need different program execution time lead to different sampling time, these parts all lead to different vibration and noise performance. Improvement of compressor drive system can decrease compressor vibration and noise, different drive arithmetics have different vibration and noise effection is tested through experiment. Simple operation on torque side and speed side can lead to obvious reduction effect of compressor vibration through analyzation of simulation results. On the base of need not additional system complication and cost, reduction of rolling piston compressor speed ripple on the software and arithmetic layer is realized. The effection of vibration reduction is different at different speed through analyzation. To low speed effection is usually more obvious and the effection is more unobvious when speed is higher. It is said to low speed improvement of speed ripple is larger through improvement of software and arithmetic.