Experimental Study On Variable Frequency Air Conditioner For Rail Transit Vehicles

In the field of air conditioning for rail transit vehicles,the traditional fixed frequency air conditioning system has been unable to meet the energy saving,comfortable,green travel concept,variable frequency air conditioning system is a strong impact on the traditional rail vehicle air conditioning market.In this paper,the experiment and research on the variable frequency air conditioning system for railway vehicles.Including the design of the overall system control program,and the problem of sampling blind area in the current sampling process is presented by using the double resistance alternating current sampling method in the driving circuit.analyzing the communication protocol between the parts of the system,and designing the hardware and software of the indoor and outdoor units.Based on the mathematical model of permanent magnet synchronous motor(PMSM),the space vector control method is analyzed and studied.By building the experimental platform of the variable frequency air conditioner prototype for rail vehicles,the overall structure and the working principle of the main components are studied.Analyzing the current waveform of the outdoor fan at different operating frequencies,and the power consumption and the cooling capacity of different frequency are compared with the fixed frequency air conditioner.At the same time,the current waveform of the compressor at different frequencies is studied to analyze the influence of double resistance current sampling on the stability of the motor.The refrigeration performance of variable frequency air conditioning system is tested,and the cooling capacity and energy efficiency ratio parameters are obtained.The results show that the cooling capacity in the 25~50℃ range is 22.3% higher than that of the fixed frequency air conditioner.When the ambient temperature reaches 32,Compared with the fixed frequency air conditioner,the energy efficiency ratio of COP is increased by 1℃ on average with an increase of about 0.08.It can be concluded,for rail traffic vehicle inverter air conditioner not only better than the traditional cooling performance of the fixed frequency air conditioner,and experience the comfort in the premise of guarantee,its energy efficiency is also higher than the fixed frequency air-conditioning system under the same conditions.