Maximum Torque Control of Induction Traction Motor Based on DQ Axis Voltage Regulation

Transcription

1 6th Intenational Confeence on Machiney, Mateials, Envionent, Biotechnology and Copute (MMEBC 016) Maxiu Toque Contol of Induction Taction Moto Based on DQ Axis Voltage Regulation Guo-Bin SUN1,a, Shu-Jia MU1,b,, Hua I,c, and Fei IN,d 1 CRRC QINGDAO SIFANG ROING STOCK RESEARCH INSTITUTE CO., td, Qingdao, 66031, China BEIJING JIAOTONG UNIVERSITY, Beijing, , China a usasoldie_sgb@163.co, bushujia847@163.co, c @bjtu.edu.cn Keywods: Weakening contol; Induction oto; Indiect-field oientation. Abstact. In the high powe taction diving syste, induction oto is widely used with its advantages of stong stuctue, high eliability and low cost. When the voltage souce invete is used as the diving device of the induction oto and the oto speed exceeds the ated speed, it is equied to conside the liit of DC bus voltage and invete ated cuent. Theefoe, an appopiate field weakening contol stategy is needed to educe the oto flux, and to enhance the output toque of the oto when induction oto opeation in the filed weakening egion. Accoding to the above pobles, consideing the DC side bus voltage liit and the invete cuent liit, this pape focuses on the analysis the cuent distibution of induction oto in the field weakening egion to achieve axiu toque output, and poposes a ethod which achieve the axiu toque output in full speed ange based on the DQ axis voltage egulation. In the final, the siulation esults ae veified on the MATAB/Siulink siulation platfo. 1. Intoduction In ail tansit, the asynchonous oto is widely used fo its siple stuctue and stong adaptability. Fo high powe taction dive syste, it is vey ipotant to achieve high pefoance contol pefoance in the whole speed ange. Especially when the oto opeates in the field weakening egion choosing appopiate contol stategy has a vey ipotant influence on the contol pefoance of induction oto, due to the liitation of DC side voltage, stato cuent nonlinea factos and the ipact of back EMF. In the high powe taction diving syste, it is vey difficult to select the appopiate oto flux in the high-speed egion of induction oto. Too lage o too sall a value of oto flux ay lead to a decease in developed toque, and thus the deteioation of oto opeating pefoance, such as dynaic behavio and convesion efficiency. Accoding to this, it has been poposed a lot of the flux weakening contol stategy. The siplest ethod is to let the oto flux efeence be invesely popotional to the oto speed [1,]. In [1], the opeation pinciple of the 1/ ω ethod is explained. The ain poble of this contol stategy is that the oto flux is not popely selected. The eseaches ade in [] take the voltage liitation into consideation based on the conventional 1/ ω ethod. Weakening contol stategy [3] adopted in accodance with the oto odel to calculate a easonable stato excitation cuent coand. Since the calculation in accodance with the steady-state oto odel paaetes to obtain the paaetes of the cuent coand of highly sensitive, especially in cetain oto paaetes affected by agnetic satuation, fequency and tepeatue will change daatically. Tansient odel of induction oto ae used to calculate the efeence cuent coand, which ipoves its obustness to a cetain extent in [3]. In [4], the efeence flux cuent coand value calculated by adding a stato voltage loop, theeby geatly enhancing the obustness of the oto paaetes. The input of voltage contolle is the eo between the axiu output voltage liit and the actual output voltage. The pape [5] pointed out that an algebaic loop ay be existed in the ethod of voltage 016. The authos - Published by Atlantis Pess 005

2 contolle. To avoid the algebaic loop, PI contolle is eplaced by integal contolle. Off-line weakening contol stategy is ainly look-up table, the toque cuent and flux cuent coand value ae obtained by the look-up table in [6]. This pape established the steady-state atheatical odel of the induction oto, the voltage and cuent constaints ae eseached unde the full speed ange. By analyzing the constaints, based on eseach esults, we popose a axiu toque output of weakening contol ethod. The ethod is based on the oto field oiented vecto contol, in synchonization with the otation of the oto flux M-T coodinates, accoding to the DQ axis stato voltage egulation, achieves the axiu toque output in weakening field. In this pape, section establish the state atheatical odel of the induction oto, and analyzes the DC voltage liits, cuent liits. Accoding to the induction oto in diffeent wokspaces cuent and voltage analysis, a axiu toque output weakening contol stategy is obtained in the field weakening based on DQ axis voltage egulation in section 3. This ethod is veified on the MATAB/Siulink siulation platfo in section 4.. Cuent and voltage liitation of induction oto in the field weakening egion When the induction oto opeates in the field weakening egion, the ain objective is to ensue contol of the axiu toque output and full utilization of the oto and the invete capacity. The liitation of the ated cuent of the oto in the field weakening egion and the DC bus voltage ae shown in Eq. 1. i + i I sq sd s ax (1) u + u V sq sd s ax Whee usd and u sq is d, q-axis stato voltage, i sd and i sq is d, q-axis cuent, I is the ated cuent s.ax of oto and invento, V is the axiu output voltage of invete. s ax Fo the voltage-souce invete syste, in the synchonous otating coodinate syste, accoding to the oto field oientation, the stato voltage equation is shown below: u = ( R + R ) i + s pi ωsi R ψ sd s sd s sd e s sq () u = ( R + R ) i + s pi + ωs i + ωψ sq s sq s sq e s sd Whee s = 1 /( s) is the leakage inductance, ψ is the oto flux, ωe is the synchonous angula velocity. Cuent liit cicle U sq Incease fequency O U sd Voltage liit cicle ω ω 1 Fig. 1 the liit of cuent and voltage in the field weakening egion When the induction oto opeates in the high-speed egion, the voltage shaed by stato esistance is so sall that can be neglected. In the steady state analysis, the diffeential phase is zeo, so the Eq. can be siplified as: 006

3 u u = ωsi = ω i sd e s sq sq e s sd Accoding to Eq. 1 and Eq. 3, the DQ axis voltage liit cuve can be shown in Fig. 1 when induction oto opeates in the field weakening egion. As can be seen fo Fig. 1, in the DQ axis stato voltage coodinates, as the oto speed inceases, the cuent liit cicle constantly extended. When the speed eaches a cetain level, voltage liit cicle is all in the cuent liit cicle, at this tie, only need to conside the voltage liit. (3) 3. DQ axis stato voltage distibution fo the axiu toque output The full speed ange can be divided into thee aeas, the constant toque egion (ws <wbase), the constant powe egion (wbase <ws <w1) and the constant voltage egion (ws> w1), as shown in Fig.. T = k Tw = k Tw = k Toque e 1 e e Constant toque egion Constant powe egion T e U s e e 3 Constant voltage egion Cuent I s Voltage wbase w1 Fig. division of induction oto opeating egion In synchonous otating coodinate syste, accoding to the Eq. 3, the equation of oto output toque can be obtained. 3 3 T = n I I = n U U = ku U (4) e p sd sq p sq sd sq sd sω s e Fo Eq. 4, we can ake F = Te / k = U U. The size of F deteines the size of the oto output sq sd toque. Theefoe, a easonable allocation of DQ-axis voltage can achieve axiu toque output. 3.1 Constant toque egion In the constant toque egion, because the oto speed is lowe than the ated speed, the oto is not liited by the voltage and is only esticted by the ated cuent, theefoe, DQ axis stato voltage inceases linealy as the speed in Eq. 5. usd = ωs e s Is ax isd. ate (5) u = ω i sq e s sd. ate w 3. Constant powe egion When the speed exceeds the ated speed, the oto is not liited by the voltage and cuent. As shown in Fig. 3, if the oto flux coand still aintain the oiginal ating, oto un fo A to B` when the speed inceased fo wbase to ws1. It is clea that the opeation voltage has exceeded the axiu voltage which akes the cuent esponse decease a lot, and then leads the oto does not wok. Theefoe, in ode to pevent the voltage satuation, the oto needs un fo point B` to B by adjusting the flux coand. This will not only eet the voltage and cuent liits, but also achieves the axiu toque output. 007

4 U qs U ds ω base ω s1 Fig. 3 the liit of cuent and voltage in the constant powe egion and constant voltage egion Fo Fig. 3a, we can get distibution of DQ axis stato voltage in the constant powe egion which can achieve the axiu toque output in Eq. 6. u u sd sq = = V ωs I s 1 s s ax e s sax Vs ax ωs I 1 s e s sax 3.3 Constant voltage egion As the speed continues to incease, the oto uns fo C to D in Fig. 3b. It is clea that the toque output at point D is less than the toque output at point C. Theefoe, the optiu voltage vectos eain unchanged in the constant voltage egion. Fo Fig. 3b, we can get distibution of DQ axis stato voltage in the constant voltage egion which can achieve the axiu toque output in Eq. 7. usd = Vs ax / (7) u = V / sq s ax ω flux flux flux flux / i sd (6) u sq 0 Is ax - Isd ω T e T /3n i e p sd i sq i sq Fig. 4 the weakening contol stategy of the axiu toque output in full egion In the above, the analysis of the induction oto DQ axis voltage distibution of the axiu toque output unde full field is ealized. Theeby we obtain weakening contol stategy of the axiu toque output shown in Fig. 4. In ode to ake the stato voltage coand equal to the axiu output voltage, we can adjust oto flux coand by the q-axis stato voltage egulato when the oto opeates in the field weakening egion which can educe the q-axis stato voltage. When the oto opeates in the constant voltage egion, the axiu output toque is achieved by the d-axis stato voltage egulato. 008

5 4. Siulation esults In ode to veify the pefoance of the weakening contol stategy, a siulation odel based on MATAB is constucted. The oto paaetes used in the siulation ae shown in table 1. Table 1 oto paaetes Paaetes Size Paaetes Size Rated voltage /V 380 Stato esistance /Ω 1.9 Rated powe /kw 5.5 Roto esistance /Ω Rated cuent /A 17.9 Stato inductance /H Pole pais Roto inductance /H Rated speed(/in) 140 Mutual inductance /H The siulated oto oto flux esulting fo these two ethods fo oto speeds anging fo 0 to 3000 ev/in ae copaed in Fig 5a, and lage diffeence between the can be obseved fo the esults. In addition, the siulated output toque fo these two ethods fo oto speeds anging fo 0 to 3000 ev/in ae copaed in Fig 5b. One can obseve fo the esults shown in Fig. 5b that lage output toque ae esulted by applying the poposed ethod as the speed is inceased. Fig. 5 (a) oto flux deteined by poposed ethod and conventional 1/w ethod, (b) output toque by poposed ethod and conventional 1/w ethod Fig. 6 (a) DQ axis stato cuent by poposed ethod, (b) DQ axis stato voltage by poposed ethod Fig. 6a shows the DQ axis stato cuent by the poposed ethod. The flux cuent deceases and toque cuent inceases in the constant powe egion. The flux cuent and toque cuent both deceases in the constant voltage egion. Fig. 6b shows the DQ axis stato voltage by the poposed ethod. The siulation esults sae as the theoetical calculation. The d-axis voltage inceases and the q-axis voltage decease in the constant powe egion. The d-axis voltage is equal to the q-axis voltage in the constant voltage egion. 009

6 5. Conclusions In this pape, accoding to the steady state equation of induction oto, the estiction of cuent and voltage in field weakening egion is studied. In addition, weakening contol stategy is poposed based on DQ axis stato voltage egulation, to achieve the axiu toque output. The stategy does not equie pecise oto paaetes and coplex calculations to select the appopiate oto flux. What oe, it has a good effect on ipoving the pefoance of induction oto in field weakening egion. Refeences [1] Novotny, D.W., and ipo, T.A.: Vecto contol and dynaics of AC dives, Claendon Pess, Oxfod, 1996 [] A. M. Khabadkone and J. Holtz, Copensated synchonous PI cuent contolle in ove odulation ange and six-step opeation of space-vecto odulation-based vecto-contolled dives, IEEE Tans. Ind. Electon.,vol. 49, no. 3, pp , Jun. 00. [3] J. K. Seok, Field weakening contol ethod in induction oto, U.S. Patent , Aug. 15, 000. [4] M. Mengoni,. Zai, A. Tani, G. Sea, and D. Casadei, A copaison of fou obust contol schees fo field-weakening opeation of induction otos, IEEE Tans. Powe Electon., vol. 7, no. 1, pp , Jan.01. [5]. Hanefos, K. Pietilainen, and. Geta, Toque-axiizing field-weakening contol: design, analysis, and paaete selection, IEEE Tans. Ind. Electon., vol. 48, no. 1, pp , Feb [6] G. Gallegos-opez, F. S. Gunawan, and J. E. Waltes, Cuent contol of induction achines in the field-weakened egion, IEEE Tans. Ind. Appl., vol. 43, no. 4, pp , Jul./Aug