機(jī)車服務(wù)廠空氣壓縮機(jī)節(jié)能控制系統(tǒng).外文翻譯

1、J. Electromagnetic Analysis revised March 12th, 2009; accepted March 20th, 2009.ABSTRACTThe actuality and disadvantages of traditional high power asynchronism motor drive air compressor in locomotive service plant are d

2、iscussed. In order to reduce the energy consumption and obtain safe running, a variable frequency control method to the motor is supplied. A PLC with touch screen is used for monitoring the status of the compressor and i

3、ts control system. It also presents energy consumption analysis caused by the variable frequency control method in a locomotive service plant.Keywords: Variable Frequency, Air Compressor, Locomotive Service Plant1. Intro

4、duction Air compressor is a key equipment to provide air power, which is driven by asynchronism motor. Air compressor is operated by adjusting rotation speed of the motor. In general, the output air pressure in pipeline

5、of the air tank is acted as controlling object in the system. The air pressure in the pipeline is controlled to be fluctuate in a certain range. Its upper limit (0.7MPa) is under the rating pressure of the pipeline, and

6、 its lower limit (0.4MPa) is above the rating pressure of the equipment using the compressive air. Usually, there are two ways to control the air pressure in the pipeline to content this demand. The first method is start

7、ing up and stopping the motor continually for adjusting air pressure in pipeline. When the air pressure is under the upper limit, the air compressor operates until the air pressure goes up to the upper limit, then the mo

8、tor stops running. But the air pressure will be lowered with air leak or air consuming equipment operating. When the air pressure goes down to the lower limit, the motor begins to work and air compressor operates again.

9、This method is simple and low cost, but it is suitable for small power motor because the motor will be started up continually. The second method is using pressure valve to limit air pressure in the pipeline. When the pre

10、ssure goes up to the upper limit pressure, the valve will close entrance of the air compressor, then the compressor is in idle state. In this case, the compressor is still driven in operation by the motor, but it does no

11、t export compressive air, so the air pressure will not go up further. When the pressure goes down to the lower limit, the valve will be open again, and then the compressor exports compressive air and the air pressure wil

12、l be up again. The variable air pressure is same as that of the first method. In this case, motor is running continuously, which can be used for high power motor. In locomotive serve plant, the second method is widely us

13、ed for control the air pressure from air compressor because of high power motor being used, which rating power is about 100KW. Although the motor is in running operation, its starting up should be controlled. Traditional

14、ly, there are two ways In Figure , a transducer of YASKAMA 616PC5 forms the air pressure feedback control system. On the transducer, FS, FV, FI and FC are ports of pressure enactment and feedback input signal. The FS pro

15、vides power supply (+15V). An input voltage, which deter-mines frequency of AC power supply from the transducer, is linked to the FV port from a resistor (4.7K). A feed-back voltage of air pressure in the air tank detect

16、ed by a remote pressure gauge is linked to FI port. These two signals are compared in the transducer and an error can be calculated, by which PID arithmetic is used for calculating control variable. The transducer has se

17、lfeducated ability, i.e. PID parameters can be adjusted automatically in terms of actual pressure change characteristic in the transducer.S1, S3, S4 and SC are ports for several control functions. When K1 is closed, the

18、transducer operates normally. If there is a failure outside the transducer, K2 will be closed, and the transducer will stop operation. In this case, a signal can be detected in S3 port to protect the whole system. Howeve

19、r, if there is a failure in the transducer, MA and MC ports will be connected in it, by which control system (PLC) can stop the whole system operation. When the failure is removed, control system makes K3 close, a signal

20、 inputs to the S4 port, which can reset the transducer. M1 and M2 ports output running state signal. Three-phrase AC power supply are linked to R, S, and T ports on the transducer. Then, the variable frequency AC power s

21、upply can be exported from U, V, and W ports.A PLC acts as a control unit in the system, from which switches K1, K2 and K3 can output relative signals. Signals from ports M1, M2, MA and MC on the transducer can also be i

22、nput to the PLC.2.2 Existing Problems and SolutionsUsing the transducer would generate harmonic wave. The external input industrial frequency power supply AC (380V/50Hz) is rectified into DC by threephrase bridge. Finall