外文翻譯--基于plc與頻率控制的加熱系統(tǒng)（英文）

1、Heating systems with PLC and frequency controlSalah Abdallah, Riyad Abu-Mallouh *Department of Mechanical and Industrial Engineering, Applied Science University, Amman 11931, Jordana r t i c l e i n f oArticle history:Av

2、ailable online 18 July 2008Keywords:Heat treatmentPLC controlFrequency controlTemperinga b s t r a c tIn this work, medium capacity controlled heating system is designed and constructed. The programmingmethod of control

3、of heating process is achieved by means of integrated programmable logic controller(PLC) and frequency inverter (FI). The PLC main function is to determine the required temperatures levelsand the related time intervals o

4、f the heating hold time in the furnace. FI is used to control the dynamicchange of temperature between various operating points. The designed system shows the capability forfull control of temperature from zero to maximu

5、m for any required range of time in case of increasing ordecreasing the temperature. All variables of the system will be changed gradually until reaching theirneeded working points.An experimental study was performed to

6、investigate the effect of tempering temperature and temperingtime on hardness and fatigue resistance of 0.4% carbon steel. It was found that increasing tempering tem-perature above 550 ?C or tempering time decreases the

7、hardness of the material. It was also found thatthere is a maximum number of cycles to which the specimen can survive what ever the applied load was.? 2008 Elsevier Ltd. All rights reserved.1. IntroductionHeat treatment

8、is the controlled heating and cooling of metals to alter their physical and mechanical properties without changing the product shape. Heat treatment is often associated with increas- ing the strength of material, but it

9、can also be used to alter certain manufacturability objectives such as improve machining, improve formability, and restore ductility after a cold working operation. Thus it is a very enabling process that can not only he

10、lp other man- ufacturing process, but can also improve product performance by increasing strength or other desirable characteristics [1,2]. A new single-switch parallel resonant converter for induction heating was introd

11、uced in [3]. The circuit consists of an input LC- filter, a bridge rectifier and only one controlled power switch. The switch operates in a soft communication mode and serves as a high frequency generator. A voltage-fed

12、resonant LCL inverter with phase shift control was presented in [4]. It was seen that the control strategy offered advantages in the megahertz operating region, where a constant switching frequency is required. The inver

13、ter steady state opera- tion is analyzed using fundamental frequency analyses. A cost-effective high efficiency inverter with phase-shifted pulse modulation scheme was proposed for medium power (5–30) kW induction heatin

14、g applications is discussed in [5]. The pro- posed inverter accomplishes soft switching operation over a wide power regulation range. The actual power conversion efficiency reached was 96.7%. A control method of reducing

15、 the size of the dc-link capacitors of a converter–inverter system was presented in [6]. The main idea is to utilize the inverter operation status in the current control of the converter. This control strategy is effecti

16、ve in regulating the dc-voltage level. Even the dc-link capacitor is arbitrarily small and the load varies abruptly. In [7] a method was proposed to accurately predict the mini- mum required temperature recovery consider

17、ing repeatability and accuracy of the leak detector by investigating the relation be- tween temperature recovery time and theoretical thermal time constant for various test volumes and applied pressures using PLC system.

18、 In [8] a methodology was demonstrated to design a PLC pro- gram that organized the relation between the physical inputs and outputs of the pumping tools in manufacturing systems. In [9] an experimental study was perform

19、ed to investigate the effect of using two axes tracking with PLC control on the solar en- ergy collected. The two axes tracking surface showed better perfor- mance with an increase in the collected energy up to 41% compa

20、red to the fixed surface. The PLC main function is to control the required temperature levels and the related time intervals of the heating hold time in the furnace [10]. Frequency inverter is used to control the dynamic

21、 change of temperature between various operating points [11,12].0196-8904/$ - see front matter ? 2008 Elsevier Ltd. All rights reserved.doi:10.1016/j.enconman.2007.11.017* Corresponding author. Tel.: +962 5 3740026.E-mai

22、l addresses: Salahabdalah_1964@yahoo.com, Salahabdalah_1964@hotmail.com (S. Abdallah), mallouh@maktoob.com (R. Abu-Mallouh).Energy Conversion and Management 49 (2008) 3356–3361Contents lists available at ScienceDirectEne

23、rgy Conversion and Managementjournal homepage: www.elsevier.com/locate/enconmanwhere Ed is the rectified voltage at the output of converter, Rd is the active resistance of coil and id is the coil current, iu is the input

24、 cur-rent of the inverter and ic the current of the condenser.3.2. Modeling of the furnaceThe right hand side of Fig. 2 illustrates a furnace consisting of a three phase heater in a room. The three phase heater emits hea

25、t at a rate of q1 and the room loses heat at a rate of q2.q1 ¼ 3kh ? iu ð5Þwhere Kh is the heater coefficient. Assuming that the air in the room is at a uniform temperature T and that there is no heat stor

26、age in the walls of the room, we can derive an equation describing the time rate of change in room temperature.q1 ? q2 ¼ codTdt ð6Þwhere Co is the thermal capacity of the air in the room. If the temperatur

27、e inside the room is T and that outside the room is To, thenq2 ¼ T ? To Ro ð7Þwhere Ro is the resistivity of the walls. Substituting for q2 givesq1 ? T ? To Ro ¼ codTdtHenceRocodTdt þ T ¼ Ro

28、q1 þ To ð8Þ4. Experimentation and results4.1. Testing the control system performanceIn order to test the ability of the designed control system to per- form the desired temperature control properly, succes

29、sive heat treatment experiments were performed and their results are de- scribed as follows.Fig. 3 shows the input frequency vs. time and Fig. 4 shows the temperature vs. time for the two specimens 1 and 2 where this pro

30、cess represent a heat-treatment process carried out with ramp- ing function only (i.e. the furnace and frequency inverter only are used), the holding time in this case was counted off from the mo- ment the furnace is act

31、uated (form room temperature). That is why the graph starts at 20 ?C and then temperature rise up using the ramp up function in the frequency inverter on a range of time forprogramControllerABCV1V4V2V5V3V6V7 V8 V9V12 V11

32、 V10C+-LdCiruit 1 Ciruit 2q2T Toid iuicq1uiuThree phase heaterFurnaceFig. 2. Principle circuit of frequency controlled three phase heater.Personal Computer PLCAnalog UnitFrequency InverterParameter UnitThree Phase Heater

33、Program to control the slope of temperature TProgram to cntrol the temperature levelFig. 1. Block diagram of PLC and frequency controlled heating system.3358 S. Abdallah, R. Abu-Mallouh / Energy Conversion and Managem