Optimum Sway Control for Overhead Traveling Cranes

Transcription

1 Optimum Sway Control for Overhead Traveling Crane KAMAL A. KHANDAKJI, K. P. ZDROZIS Department of Electrical Engineering, Tafila Technical Univerity Tafila, JORDAN; Department of Automation, Technological Educational Intitute of Thealoniki, Sindo P.O. Box : 4, GREECE; zdrozi@teithe.gr Abtract: - Sway control for indutrial application and for crane particularly i a hitorical problem that ha accompanied the development in power emiconductor ince the 980. Thi article propoe a power emiconductor drive ytem, which can be ued in the anti-way control of overhead crane driven three-phae induction motor. The developed ytem i baed on the rotor current control. The propoed power emiconductor drive ytem i imulated uing the developed comprehenive mathematical model. The performance of the propoed ytem i analyzed and compared to voltage-controlled anti-way ytem. A prototype of the propoed anti-way control ytem i developed at the laboratory of electric drive and automation in ATEI Greece, while the mechanim prototype wa developed by the project ponor - Arab Manufacture Company in Amman Jordan. Key-Word: - Anti-way control, overhead traveling crane, controlled current converter, three-phae induction motor. Introduction In the lat decade AC power emiconductor drive, baed on different kind of AC motor, have become the mot pread electromechanical ytem to generate controlled motion with high accuracy and dynamic requirement. Modern crane are a good example of uch electromechanical ytem, which are equipped with ac power emiconductor drive alo. The productivity of overhead traveling crane depend on the time required for the crane to hoit, tranport and lower a load, i.e. the crane cycle time. The upended load way i a major problem that occur at load tranportation, increaing the total crane cycle time and thu decreaing the crane productivity in general. The olution of uch problem wa and till a crucial iue for crane deigner and reearcher a well [-6]. In [7] a pecial control algorithm for upended load antiway wa developed, the developed motor torque algorithm can be realized uing different power electronic circuitrie. In thi paper two power electronic drive ytem are developed for anti-way control and adjuted with the torque algorithm given in [7]. The firt ytem i baed on the reverible power controller (RPC), the output voltage of which i a function of the firing angle, i.e. oft tarter. Therefore, the motor torque can be controlled with a pecial algorithm tored in the controller. Nowaday, oft tarter ue pecial control trategie that eliminate electromagnetic torque pulation at tarting and recloing, and keep the line current nearly contant at a preet value over the entire tarting period [8]. The torque pulation elimination trategy define the triggering intant of the ofttarter of the upply voltage (Fig. ). Thyritor of the voltage controller are triggered in the equence marked in Fig., reulting in a phae difference of 60 between conecutive witching during tarting a well a in the teady tate, excluding the firt energization cycle. In order to eliminate upply frequency pulation in the electromagnetic torque, different witching trategie are ued for T, T, and T3, on the firt upply voltage cycle for continuou and dicontinuou line current cae, depending on whether triggering angle α i le or greater than the power factor (pf) angle of the machine at unity lip [8]. The econd anti-way electric drive ytem i baed on a thyritor current-converter (TCC), which can be connected to the rotor winding of the lip-ring induction motor. The rotor current determine the motor torque, thu the required motor torque algorithm can be realized by creating the appropriate firing of the thyritor of the converter. In the current paper, a try to create an anti-way control uing current converter for three-phae induction motor driven electric drive i performed. ISSN: Iue 6, Volume 7, June 008

2 Deign Conideration The block-diagram of the anti-way electric drive ytem baed on the RPC i hown in Fig. (a), a peed et point (V in ) i applied at the input of the control ytem (CS), where it i added to the negative peed feedback ignal (V fb ), the formed error i then applied to a PID peed controller. After a ignal proceing at the controller tage, the output ignal of the controller i applied to the firing circuit of the RPC (revering oft tarter), then the thyritor of the oft tarter are triggered with a finite firing angle α, which correpond to a finite rm value of the voltage acro the oft tarter. The oft tarter voltage i applied to the tator winding of the 3-phae induction motor (IM). Fig.: Schematic diagram of oft tarter The rotor winding of the 3-phae lip-ring IM i connected to external reitor R ext and R ext, thi greatly increae the range of peed regulation of the ytem. Thu, in thi ytem the motor torque i controlled by varying the tator voltage and the rotor reitance. In Fig. (b), the block-diagram of the propoed antiway electric drive ytem i hown, a peed et point (V in ) i applied at the input of the control ytem (CS), where it i added to the negative peed feedback ignal (V fb ), the formed error i then applied to a PID peed controller. After a ignal proceing at the controller tage, the output ignal of the controller i applied to the firing circuit of the TCC. The function of the current converter i to control the rotor current and thu the motor torque to achieve the required torque diagram for anti-way control. 3 Deign and Analyi of the Power Circuit The power circuit of the two above-mentioned ytem are hown in Fig. 3. Varying the firing angle α in the RPC ytem, the RMS value of the voltage applied to the tator winding i alo varied. ISSN: Iue 6, Volume 7, June 008

3 Thi permit a torque regulation of the motor. The exitence of the additional reitance in the rotor circuit R ad permit a peed regulation with α = variable. RPC CS ΔV V in TG IM TG V fb V fb R add V in ΔV R ad Current Converter CS (a) (b) Fig. : Block-diagram of the anti-way revering power controller (a) and thyritor current controller (b) ytem The thyritor-current converter (TCC) ytem permit a mooth rotor current regulation. Varying the firing angle α of thyritor T-T3, which are connected in erie with the additional reitor R ad and in parallel with R ad. If α = α min then only R ad i active in the rotor circuit and R ad i hort-circuited. If the thyritor are turned off, i.e. α = α max then R ad i in erie with R ad. Therefore, varying α, a family of peed-torque characteritic laying between two extreme characteritic - when α = αmin and - when α = α max are formed (Fig. 4). To minimize cargo ocillation uing TCC, it i required to know the firing algorithm of thyritor T-T3 o that the motor torque remain contant over the tarting/topping period, and the ign of the torque could be changed twice over the tranient period of tarting or topping [7]. For thi purpoe we need to find the relationhip between the motor lip () and the firing angle (α) o that the motor torque remain contant. The load-phae angle of the rotor circuit can be determined a follow: ϕ r = tan - (X r S)/R r () Where X r and R r the reactance and the reitance of the rotor circuit, repectively. Varying and uing univeral characteritic, we can find the value of coefficient K r and X r with the help of which the equivalent rotor reitance and reactance can be calculated a follow: R eq = R r K r X eq = X r K x () The motor torque can be calculated uing the following formula: T T ( + a ) max max = (3) max + + a max max where T max the maximum motor torque occurring at = max max R R eq + ( X + X ) ISSN: Iue 6, Volume 7, June 008

4 CF CR T-T6 R ad T-T3 R ad R ad (a) (b) Fig. 3: The power circuit of the RPC ytem (a) and the TCC ytem (b) Calculation were made for a real 3-phae induction motor with the following rating: P = 45kW, n = 576 rpm, T max = 940Nm, R = 0.084Ω, R = Ω. The value of the additional rotor reitance are: R ad = R = 0.77Ω R ad = 3.6Ω The relationhip α = f() with a motor torque =. of the nominal motor torque wa calculated. With the ame torque condition the tator (I ) and rotor (I ) current were calculated for both ytem. The reult of calculation are hown on Fig. 5 and Fig.6. Knowing the firing algorithm α = f() with contant motor torque, it i poible to imulate the operation of the traveling mechanim over a full-cycle. The reult of modeling are hown are hown in Fig. 7. From Fig. 7, it i een that the propoed thyritor current converter ytem can be uccefully ued for anti-way control. By the end of tarting, the load-way angle α wa reduced to zero, after that the upended load wa kept in a vertical poition without way over the teady-tate period. At topping, the upended load deviate with a negative angle α, and by the end of topping, the load wa returned back to the ame poition with zero way angle. The motor torque diagram wa alo uccefully realized in accordance with the diagram derived in [7] for anti-way control. 4 Qualitative Analyi To make a complete comparion between both ytem, calculation for the equivalent tranient and teady-tate tator-current (I eq ) and rotorcurrent (I eq ) for both ytem have been developed. For the full-cycle operation, the traveling ditance wa varied to get more information about the behavior of both ytem. The reult of calculation are hown in Table and. Table : Equivalent current of the traveling electric drive at tarting and topping TCC RPC Proce I eq, p.u. I eq, p.u. I eq, p.u. I eq, p.u. t, Starting Stopping ISSN: Iue 6, Volume 7, June 008

5 Table : Equivalent current of the traveling electric drive for a complete cycle of operation Sytem TCC RPC Traveling ditance, m I eq, p.u. I eq, p.u. I eq, p.u. I eq, p.u T c,, p.u. 0.5 T m, p.u. Fig. 4: Two extreme peed-torque characteritic and Fig. 5: The relationhip between the motor-lip () veru the firing angle (α) with a contant motor torque =.5 of the rated value ISSN: Iue 6, Volume 7, June 008

6 I, pu I, pu (a) (b) Fig. 6. Motor peed veru tator-current characteritic (a) and motor peed veru rotor-current characteritic (b). - uing TCC, - uing RPC. 4 Concluion Two cloed-loop power emiconductor drive ytem for anti-way control of overhead traveling crane driven three-phae induction motor are developed. The firt ytem control the motor torque by changing the intantaneou voltage applied to the tator winding, while the econd ytem control the motor torque by changing the rotor current. Two comprehenive mathematical model for both anti-way ytem are ued to imulate the effectivene of uing the propoed ytem for load anti-way purpoe in overhead crane. A prototype of the propoed anti-way control ytem i developed at the laboratory of electric drive and automation in ATEI Greece, while the mechanim prototype wa developed by the project ponor - Arab Manufacture Company in Amman Jordan. T, ω, α ω T T α α t t t 3 t 4 t 5 t 6 Fig. 7: Simulation reult of the crane traveling electric drive for a full-cycle operation ISSN: Iue 6, Volume 7, June 008

7 The performance of the propoed ytem i analyzed. Reult of imulation and experimental analyi how that both electric drive ytem do eliminate upended load way; in the TCC ytem, the tator equivalent current i le than the tator equivalent current in the RPC ytem by 0%. The rotor equivalent current (over a complete crane cycle of operation) in the TCC ytem i alo le than the rotor equivalent current in the RPC ytem by 0%. Thu, it i recommended to ue the TCC ytem. Acknowledgement The author thank the adminitration of Tafila Technical Univerity (TTU) Jordan and Alexander Technological Educational Intitute of Thealoniki (ATEI) Greece for their upport by providing the neceary facilitie for thi work preparation. Reference: [] Jianqiang Yi Yubazaki, N. Hirota, K. Antiwing Fuzzy Control of Overhead Traveling Crane, Fuzzy Sytem, 00. Honolulu, HI, USA, -7/05/00. IEEE Proceeding. Vol., pp [] Jung Hua Yang and Kuang Shine Yang. Adaptive Coupling Control for Overhead Crane Sytem, Mechatronic. Elevier. Vol. 7. Iue -3, March-April 007, Page [3] Yanai, N. Yamamoto, M. Mohri, A. Anti-way Control for Wire-upended Mechanim Baed on Dynamic Compenation, Intelligent Robot and Sytem, 00. IEEE Proceeding. Vol. 4, pp ISBN: [4] Yanai, N. Yamamoto, M. Mohri, A. Feedback Control for Wire-upended Mechanim with Exact Linearization, Intelligent Robot and Sytem, 00. IEEE Proceeding. Vol. 3, pp 3-8. ISBN: [5] Yong-Seok Kim; Han-Suk Seo; Seung-Ki Sul. A New Anti-Sway Control Scheme for Trolley Crane Sytem. Indutry Application Conference, 00. IEEE Proceeding. Vol., pp [6] Khandakji K.A. and Zdrozi K. Determination of Quality Parameter of Hoiting Electric Drive Sytem with 3-phae Induction Motor, Proc. 5th International Conference on Technology and Automation, 005. pp [7] Kamal Khandakji. Minimization of Load Ocillation in Travelling Mechanim of Crane, American Journal of Applied Science. Science Publication. Vol., Iue 5, 005. pp [8] Gürkan Zenginobuz, I ık Çadırcı. Soft Starting of Large Induction Motor at Contant Current with Minimized Starting Torque Pulation, IEEE Tranaction on Indutry Application, Vol. 37, Iue 5, September/October 00, pp [] Dewan S.B., Slemon G.R., Straughen A. Power Semiconductor Drive. Jhon Wiley & Son, 984. Biography: Dr. Kamal Abd Al-Majeed Khandakji received hi Ph.D. in Electric Drive and Automation in 999 from Lvov National Polytechnic Univerity. In 000, he joined Al-Balqa' Applied Univerity then Tafila Technical Univerity in 005. Currently, he i an aociate profeor and Vice Dean of the Faculty of Engineering. Hi reearch interet include enhancing the performance of electric drive uing microproceor control, invetigation of abnormal mode of power emiconductor drive and viual poitioning. Biography: Dr. Koma Zdrozi received hi Ph.D. in Electric Drive and Automation in 00 from Odea National Polytechnic Univerity. In the ame year, he joined Alexander Technological Educational Intitute of Thealoniki. Currently, he i an aociate profeor and Vice Head of the Department of Automation. Hi reearch interet include invetigation of the dynamic behavior of hoiting electric drive and their optimum control, programmable inverter and PLC. ISSN: Iue 6, Volume 7, June 008