Modelling and Simulation of Locomotives with Traction Induction Motors and Three Levels Converters

Transcription

1 Proceedings o the 7th WSEAS International Conerence on Systems Theory and Scientiic Computation, Athens, Greece, August 4-6, Modelling and Simulation o Locomotives with Traction Induction Motors and Three Levels Converters DANIEL CRISTIAN CISMARU DORU ADRIAN NICOLA GHEORGHE MANOLEA MIRCEADRIAN DRIGHICIU Faculty o Electromechanical Engineering University o Craiova Decebal, 107 ROMANIA dcismaru@em.ucv.ro dnicola@em.ucv.ro ghmanolea@em.ucv.ro adrighiciu@em.ucv.ro Abstract: - The paper describes the mathematical models and structural diagrams o the three levels voltagesource inverter and line-side converter used on the locomotive ed rom AC line. The overall structural diagram construction or the principle schemes corresponding to modern locomotives is also presented. At the end are shown the simulated waveorms o the three levels converters. Key-Words: - modelling, locomotive, electric traction, three levels converters, simulation 1 Introduction Utilization in the electric traction o the induction motor with squirrel cage it is possibly only in this eeding condition with a three-phase system by voltages o amplites and requency controlled variable. This eeding type it is achieved by means o machine-side converter (CM), usually a voltagesource inverter (IT) with two or three levels (Fig.1,a). As a rule, the main electric circuits o modern locomotive (Fig.1) ensure two conversion stages o the electric energy, the irst being achieved by lineside converters and the second, by machine-side converters [1], [], [3]. In the case o AC- line supply, the line-side converter is a our-quadrant converter (C4Q) with two (N) or three levels (3N), associated to a voltage-source inverter (IT3N), which represents the machine-side converter (Fig.1). The modelling o such line-side converters can use the switching unctions method, which oers a high generality degree. As ar as the model implementation into simulation sotware is concerned, the switching unctions approach presents the advantages o reduced simulation time and good convergence. For three levels converters, the switching unctions with three levels 3w [4], [5] are used. For the modelling o dierent converter structures by means o switching unctions, it has been considered that the switching devices are ideal, by neglecting the commutation time and orward voltage drop. Such a converter is considered ideal (without losses). a) basic scheme b) B 0 B 0 locomotive main electric circuits Fig.1 Basic scheme and main electric circuits used in modern locomotives with three levels converters

2 Proceedings o the 7th WSEAS International Conerence on Systems Theory and Scientiic Computation, Athens, Greece, August 4-6, Fig. Three-phase voltage-source inverter with three levels (IT3N) Modelling o the Machine-Side Converter For the modelling o the machine-side converter, that being the three levels voltage-source inverter, they are used the commutation unctions with three levels [5], [6]. From viewpoint o modelling, any static converter it can be approached like a "black box" with input/output characteristics through the commutation unctions intermediation. For the dierent structures modelling o converters by means o commutation they have been considered that the used semiconductor devices they are ideally, they are neglected both the commutations times and the voltage drop at conduction in orward direction. Such converter is ideal and it is considered without losses. For modelling o three-phase voltage-source inverter with three levels (Fig.) it is considered the ideal case, at which two identical capacitors they divide in equal mode the constant voltage u d. For modelling they are used the commutation unction with three levels 3w : +1, Ti, Ti1 3w R, S, T = 0, Ti1, Ti ', i=1,, 3 (1) -1, Ti ', Ti1' Analysing the topology o three-phase voltagesource inverter with three levels (Fig.) they can be written the equations: u RO = 3wR ; uso = 3wS ; uto = 3wT ; i = ir 3wR + is 3wS + it ; d 3wT () urn = uro - u NO ; usn = uso - u NO ; utn = uto - u NO ; uro + uso + uto u NO = ; 3 On these equations basis, it is obtained the structural diagram o three-phase voltage-source inverter with three levels (Fig.3). This model have comprised in their structure the MAT traction induction motor model (both the electromagnetic part and mechanic part) [], [6], the link with this making through the voltage (u s ) and respectively by the stator current (i s ) space phasors. Fig.3 Structural diagram and mask block or three-phase voltage-source inverter with three levels

3 Proceedings o the 7th WSEAS International Conerence on Systems Theory and Scientiic Computation, Athens, Greece, August 4-6, Modelling o the Four-Quadrant Line-Side Converter In order to obtain the mathematical model o the our-quadrant line-side converter with three levels (Fig. 4), the ollowing switching unctions are used: +1, T1, T11 +1, T, T1 3wA = 0, T11, T1 ' ; 3wB = 0, T1, T' (3) -1, T1 ', T11' -1 T', T1' Fig.4 Structure o the our-quadrant line-side converter with three levels C4Q3N By means o these unctions, the ollowing voltage and current expressions, respectively, can be written: uao = 3wA ; ubo = 3wB (4) u = uab = uao - ubo = ( 3wA - 3wB) = 3wAB i4q = i 3wA - i 3wB = i ( 3wA - 3wB) = i 3wAB (5) With reerence to the electric circuit o Fig.4, the ollowing equations can be added to (4) and (5): di u T = Lk + u dt i4q = if + id ; id = id1 + id dif 1 = L + i dt dt F (6) C C du d id1 = dt u = 3wAB ; i4q = i 3wAB Based on the above system o equations, the structural diagram and mask block o the ourquadrant line-side converter with three levels are obtained in Fig.5. The input quantities are: - u T, the voltage rom the transormer secondary; - i d, the input current rom the inverter (machine-side converter); - the switching unctions, which allow the ourquadrant operation control o line-side converters, being generated by the traction control system. The DC-link voltage u d represents the output quantity or the our-quadrant line-side converters and, in the same time, the input quantity or the inverter (machine-side converter) model. 4 Structural Diagrams or AC Locomotives With the obtained structural diagrams, as well as the mask blocks o other components o the main electric circuit, it is possible to build the structural diagrams or the modern locomotives ed rom AC contact line having the main circuit schemes given in Fig.1. Fig.5 Structural diagram and mask block o the our-quadrant line-side converter with three levels

4 Proceedings o the 7th WSEAS International Conerence on Systems Theory and Scientiic Computation, Athens, Greece, August 4-6, Fig.6 Structural diagrams o the main electric circuits o Fig.1 a) The locomotives with traction induction motors ed rom the AC contact line they have obligatory two conversion phases, through the existence o network converter (our quadrant converter). The basic scheme modelling o the traction induction motor eeding (Fig.1., a) it can make easily by means o the mask blocks o the our quadrant converter with three levels ( C4Q3N ) and o the voltage-source inverter ed traction induction motor ( IT3N+MAT ) [], [6]. It is obtained thus the structural diagram (ig.6) having like input variables the u T (voltage rom the transormer secondary) as well as the switching unctions o those two converters. The output variables can be considered anything among variables rom the mask blocks inside, depending on the sties regime or the possibly connections with other sub-systems. For the structural diagram construction o the entire main circuit, corresponding to a high-speed train (Fig.7), the previous diagram it is multiplied o our time (the total numbers o motors) and they are written the proportionality relations what they describe the traction transormer working. For the identiication o the blocks and o the quantities corresponding to those our traction secondary they have been used superior indexes. Like input and output variables they have been considered those which interact with the contact line, the u LC voltage and the i LC current absorbed by the train. For obtainment o this rom behind, given the previous cases, it was necessary the utilization, rom the our quadrant converters inside, o the i (i),i = 1,4 currents rom the traction transormers secondary. 5 Simulink Model Based on the presented structural diagram (ig.6), its SIMULINK model has been achieved, as shown in Fig.8. They are obtained the identical SIMULINK model rom viewpoint topology with associated structural diagram. Using this SIMULINK model (Fig.8), the operation o a our-quadrant line-side converter together with a voltage-source inverter with two levels and a traction induction motor has been simulated (ig. 9). Fig.7 Structural diagrams o the main electric circuits (B 0 B 0 locomotive)

5 Proceedings o the 7th WSEAS International Conerence on Systems Theory and Scientiic Computation, Athens, Greece, August 4-6, Fig.8 SIMULINK model o the main electric circuits o Fig.1 a) Fig.9 Waveorms o simulated system quantities 6 Conclusions The imposed speciic eatures o the utilization in electric traction o equipments used in modern locomotives ed rom AC contact line can be sties by means o the simulation. In this context it is necessarily a mathematical modelling consorted o the structural diagrams obtainment what permit the immediate implementation within the ramework o a simulation sot like MATLAB- SIMULINK. With the obtained structural diagrams, as well as the mask blocks o other components o the main electric circuit, it is possible to build the structural diagrams or the locomotives with traction induction motors ed rom AC contact. It is observed the acile modality by achievement o the structural diagram corresponding to a complex circuit rom viewpoint topology. Otherwise, it is achieved a construction on our levels, easy to sty modiied and implemented in a simulation sot like MATLAB-SIMULINK. It is possibly, the integration o this diagram in to another more complex, how it would be that which it is stied the interaction between the traction substation and motor electric vehicles, too. Reerences [1] D.A. Nicola, D.C. Cismaru, Bazele trac"iunii electrice, Vol.I, Ed. Sitech, Craiova, [] D.C. Cismaru, Modelarea 'i simularea ac"ion)rilor cu motoare asincrone speciice trenurilor de mare vitez), Tez) de doctorat, Craiova 003. [3] F. Perticaroli, Sistemi elettrici per i trasporti, Ed. Mason, Milano, [4] M. Carpita, A. Monti, Voltage Source Converters and Drives Simulation at System Level or Control Design Applications, "EPE Journal", Vol.5, No3/4 Jan 1996, p [5] D. FloricNu, Sisteme de comand) pentru convertoare statice de putere, Ed. Printech, BucureOti, [6] D.A. Nicola, D.C. Cismaru, Modelling o voltage-source inverter ed traction induction motor, SIELMEN 003, ChiOinNu, 003.