Implementation of Field Oriented Speed Sensorless Control of Induction Motor Drive

Transcription

1 International Journal on Electrical Engineering and Informatic - Volume 8, Number 4, December 216 Implementation of Field Oriented Speed Senorle Control of Induction Motor Drive R. Gunabalan 1 and V. Subbiah 2 1 School of Electrical and Electronic Engineering, VIT Univerity, Chennai, TamilNadu, INDIA 2 Department of Electrical and Electronic Engineering, PSG College of Technology, Coimbatore, TamilNadu, INDIA Abtract: Thi paper focue the hardware realization and implementation of peed-enorle field oriented control of induction motor drive. For peed enorle operation, natural oberver i applied to etimate the tator current, rotor fluxe, load torque and rotor peed becaue of it imple tructure and no direct feedback. The configuration of the natural oberver i comparable to and a well a it feature i identical to the induction motor. State pace model i applied to both the etimator and the induction motor. Load torque adaptation i provided to etimate the load torque and, peed i etimated from the torque, rotor fluxe and tator current. Direct field oriented enorle vector control cheme i ued and the rotor angle i calculated from the etimated rotor fluxe. Simulation a well a experimental reult are preented for variou peed and load condition to demontrate the performance of natural oberver in enorle vector control application. Keyword: Induction motor, DSP proceor, oberver, enorle control, imulation 1. Introduction Induction motor are favoured for very large drive becaue of the boundarie of commutation and rotor peed in dc drive. The induction motor i in fact 'bruhle' and can work with imple control without a haft poition tranducer. Induction motor control can be claified into two type: calar control and vector control. In calar control [1], the magnitude of the control variable i varied and it diregard the coupling effect in the machine. The mot popular method i V/f control, which adjut the contant volt per hertz of the tator voltage to keep the tator flux contant. The dynamic performance of V/f control i unatifactory becaue of temperature and aturation effect. Recent development in fat witching power emiconductor device and powerful digital ignal proceor made advanced control technique of induction motor. The vector control i introduced in the beginning of 197. The vector control conit of controlling the tator current repreented by a vector. Thi control i baed on tranforming a three phae time and frequency dependent ytem into a two co-ordinate (d and q axe) time invariant ytem. Thee projection lead to a tructure imilar to that of a eparately excited dc motor control. Vector control i alo called a Field Oriented Control (FOC). Generally, two type of field oriented control cheme are available. 1. Direct field oriented control 2. Indirect field oriented control. In the direct cheme, the intantaneou poition of rotor flux (θ e ) ha to be meaured uing flux enor. Thi add to the cot and complexity of the drive ytem. In the indirect cheme, a model of induction motor i required to calculate the reference angular lip frequency that ha to be added to the meaured rotor peed. The um i integrated to calculate the intantaneou poition of the rotor flux. Indirect field orientation i more enitive to parameter value inaccuracy than direct field orientation. The value of the rotor time contant (L r /R r ) i ued in the lip frequency calculation and i enitive to temperature and flux level. The need of pecial poition incremental encoder i another diadvantage of the method. To avoid thee complication, different algorithm are projected, to etimate both the rotor flux Received: September 15 th, 214. Accepted: November 8 th, 216 DOI: /ijeei

2 R. Gunabalan, et al. vector and/or rotor haft peed. The induction motor drive without mechanical peed enor have the attraction of low cot, high reliability and reduce the ize and the lack of additional wiring for enor or device mounted on the haft. Nowaday, a number of adaptive oberver deign technique are available for peed and flux etimation. The tandard peed etimator are Luenberger oberver [2] [7], Extended Kalman Filter (EKF) [8] [13], Model Reference Adaptive Sytem (MRAS) [14] [18], natural oberver [19], load torque oberver [2]-[21], liding mode oberver [22] [23] etc. The election of the oberver gain contant (K) i difficult in Luenberger oberver. The initial election of noie covariance matrice i not eay in EKF and ubequently the algorithm i complicated. The number of input in EKF and Luenberger oberver i different to the number of input to the induction motor ince they utilize output feedback. The above difficultie are overcome by introducing natural oberver for etimating the peed and alo the load torque. The paper i organized a follow: Chapter 2 dicue the concept of natural oberver. The imulation reult are preented in chapter 3. Hardware circuit and reult are preented in chapter 4 and are concluded in chapter Mathematical Model of Natural Oberver The tructure and feature of the natural oberver are identical to the induction motor for the given upply voltage and load torque. The major difference between natural and conventional oberver i that there i no external feedback and fater convergence rate. A a reult, the peed etimation follow the peed change imultaneouly. It dynamic behavior i exactly the ame a the motor and load torque adaptation i ued to etimate the load torque from the active power error. Fourth order induction motor model in tator flux oriented reference frame i ued to etimate the peed, where dq-axe tator current and rotor fluxe are elected a tate variable. The induction motor i repreented in tationary reference frame by the following tate equation: dx dt = AX + BV (1) where, Y = CX A = (R +R r ( L m Lr )2 ) σl [ 1 σl (R +R r ( L m Lr )2 ) σl L m τ r 1 B = C = [ 1 σl 1 ] [ ] σ = 1 L2 m - leakage coefficient X = [i d Y = [i d V = [V d L L r i q i q φ dr ] = i V q ] T φ qr ] T L m σl L r τ r ω r L m σl L r 1 τ r ω r L m σl L r L m σl L r τ r ω r L m 1 ω τ r r τ r ] (2) 728

3 Implementation of Field Oriented Speed Senorle L, L r tator and rotor elf inductance repectively (H) L m - mutual inductance (H) τ r -rotor time contant = L r R r -motor angular velocity (rad/) r The block diagram repreentation of natural oberver i hown in Figure 1 and the oberver tate equation are a follow: dx dt = A X + BV (3) Y = CX (4) X = [i d Y = [i d i q i q φ dr ] T = i φ qr ] T where, ^ repreent the etimated quantitie. The load torque i etimated from the active power error by the following equation [14]: T L = K P e P + K I e P dt (5) e P = V d (i d e i e d ) + V q (i q e i e q ) (6) Etimation of rotor peed i acquired from etimated tator current, rotor flux and the etimated load torque a: ω r = ( 3 ) 2 (n p ) J (L m ) L [φ dr i q φ qr i d ] T L (7) r J Where n p i the no. of pole pair and J i of inertia of motor load ytem (kg.m 2 ). The peed etimation method in EKF and Luenberger oberver alway deire ome correction term in order to follow peed change. Thi reult in the etimation alway lagging the actual value. In natural oberver, the peed etimation follow the peed change imultaneouly even for udden change occur in the load torque. Figure 1. Block diagram of a natural oberver with load torque adaptation The cloed loop arrangement of induction motor drive with natural oberver i hown in Figure 2. The reference current i d and i q are calculated a follow: i q = L r T n p L e (8) m φ r 729

4 R. Gunabalan, et al. i d i obtained by comparing the actual flux with the reference flux and the error i proceed in the PI controller which give the deired value of i d. It i alo attained by the following equation for a known flux value. i d = φ dr L m (9) The reference current are tranformed into tationary reference frame by rotor angle θ e. The two phae dq-axe tator current are tranformed into three phae reference current by 2 to 3 converion block (invere Clarke tranformation). Figure 2. Cloed loop arrangement of induction motor with natural oberver 3. Simulation Reult and Dicuion The imulation block of enorle vector control are contructed in MATLAB uing power ytem block et and imulink librarie. The imulation reult are preented for variou running condition. The rating and parameter of the induction motor ued for imulation are given in Table 1. Three phae quirrel cage induction motor of.746 kw (1HP) i ued for imulation. Direct field oriented enorle vector control cheme i ued and the rotor angle i calculated from the etimated rotor fluxe. Figure 3 how the imulation diagram of natural oberver baed enorle vector control with PI controller. Induction motor and natural oberver tate equation are contructed in m-file and called back in imulink model file. In addition, variou imple block available in imulink are ued to contruct the entire ytem. PI controller i contructed uing PID block available in imulink librarie. Simulation are carried out at a peed of 1 rpm and the imulation reult are hown in Figure 4. The motor i at no load at the time of tarting. The command peed i et at 1 rpm. At t = 1.5, a tep command i given and the peed of the motor increae from 1 rpm to 125rpm. At t=3, a load of 2.5 Nm i applied. At teady tate, the difference between etimated and actual peed i zero. The etimated and actual peed repone are hown in Figure 4 (a). It i oberved that the etimated peed follow the actual peed and it convergence rate i fat even for a udden change in load condition. The etimated torque repone i illutrated in Figure 4 (b). The etimated torque follow the load torque and no limiter i placed in the torque etimator. It i concluded that the oberver etimate the peed and load torque of the motor for a variety of running condition. 73

5 Implementation of Field Oriented Speed Senorle Figure 3. Simulation diagram of natural oberver baed enorle vector control. 731

6 Speed (rpm) Speed (rpm) R. Gunabalan, et al. Table 1. Rating and Parameter of Induction Motor Motor rating Output W R Ω Pole 4 R r 8.43 Ω Speed 1415 rpm L.715 H Voltage 415 V L r.715 H Current 1.8 A L m.689 H Connection Star f 5 Hz Actual peed Etimated peed Time (S) (a) Etimated and actual peed repone for a refrence peed of 1 rpm and 125 rpm Etimated peed Reference peed Time (S) (b) Etimated peed repone for a reference peed of 125 rpm 732

7 Load torque (Nm) Implementation of Field Oriented Speed Senorle 6 Etimated load torque Time (S) (c) Etimated load torque with 2.5 Nm load Figure 4. Simulation reult for a peed of 1 rpm and 125 rpm with 2.5 Nm load. 4. Hardware Reult and Dicuion Three-phae quirrel cage induction motor of W (1HP) i ued for both imulation and hardware et up. Brake drum arrangement are provided for mechanical loading. The central proceor unit i the TMS32F2812 DSP proceor and it execute all the mathematical calculation. Variou imulink block like natural oberver and PI controller are built in VISSIM. TMS32F2812 DSP proceor upporting block are available in VISSIM. In VISSIM, the imulation block are converted into C- code uing the target upport for TMS32F2812 and compiled uing code compoer tudio internally and the output file i downloaded into the DSP proceor through J-tag emulator. Three number of LEM current enor and voltage enor are ued to meaure the phae current and terminal voltage of induction motor repectively. The meaured analog current and voltage are converted into digital by on chip ADC with 12 bit reolution. The feedback ignal are linked to DSP proceor uing 26 pin header and the proceor etimate the tator current, rotor flux, load torque and peed. The proceor alo generate the required PWM pule to enable the three phae IGBT inverter witche in the Intelligent Power Module (IPM). Highly effective overcurrent and hort-circuit protection i realized through the ue of advanced current ene IGBT chip that allow continuou monitoring of power device current. Sytem reliability i further enhanced by the IPM integrated over temperature and under voltage lock out protection. The hardware reult for a tep peed of 1 rpm to 125 rpm for a load of 2.5 Nm are hown in Figure 5. The actual peed of the motor i meaured by proximity enor. The etimated peed and actual peed waveform are depicted in Figure 5 (a). It i identified that the etimated peed follow the actual peed and matche with the imulation waveform. The etimated peed repone with repect to the reference peed of 125 rpm i illutrated in Figure 5(b). The motor run at a contant peed of 125 rpm (1cm = 5 rpm) with a load of 2.5 Nm (1cm=1Nm). The external load i applied by brake drum mechanim and the torque i calculated uing tandard formula. The etimated torque waveform oberved under no load and a load of 2.5 Nm i illutrated in Figure 5(c) and it follow the applied load. The dq-axe tator current waveform obtained by imulation and hardware reult are hown in Figure 6. It i inferred that the hardware reult upport the imulation reult. 733

8 R. Gunabalan, et al. (a) Etimated and actual peed repone for a tep peed of 1 rpm to 125 rpm (b) Etimated peed repone for a reference peed of 125 rpm (c) Etimated torque with 2.5 Nm load Figure 5. Experimental reult for a peed of 1 rpm and 125 rpm with 2.5 Nm load 734

9 Stator current (A) Implementation of Field Oriented Speed Senorle 4 3 d-axi q-axi Time () (a) dq-axe current waveform imulation reult (b) dq-axe current waveform hardware reult Figure 6. dq-axe tator current waveform for a peed of 1 rpm and 125 rpm with 2.5 Nm load 5. Concluion The induction motor and natural oberver are modeled in MATLAB with tate pace model and imulation are carried out for different running condition. It i concluded that the etimated parameter uch a rotor peed and load torque follow the command value and the error i zero at teady tate. The ripple i very le in the etimated torque and the convergence rate are very fat. P-I controller are applied in the peed control loop to generate the torque reference and to maintain the rotor flux contant. Hardware reult are preented to validate the performance of the natural oberver and it matche with the imulation reult. The natural oberver i a imple and peedy etimator for enorle vector control of induction motor drive. 6. Reference [1]. B. K. Boe, Modern Power Electronic and AC Drive, Upper Saddle River, NJ: Prentice-Hall, pp , 21. [2]. H. Kubota, K. Matue, and T.Nakano, New adaptive flux oberver of induction motor for wide peed range motor drive, in Proc. IEEE IECON 9, vol.2, 199, pp

10 R. Gunabalan, et al. [3]. H. Kubota and K. Matue, Speed enorle field-oriented control of induction motor with rotor reitance adaptation, IEEE Tran. Indutry Application, vol. 3, pp , Sept. /Oct [4]. T. Yamada, K. Matue and K. Saagawa, Senorle control of direct field oriented induction motor operating at high efficiency uing adaptive rotor flux oberver, in Proc. IEEE, 1996, pp [5]. K. Matue, Y.Kouno, H.Kawai and J.Oikawa, Characteritic of peed enor-le vector controlled dual induction motor drive connected in parallel fed by a ingle Inverter, IEEE Tran.Indutry Application., vol. 4, pp , Jan./Feb. 24. [6]. K. Matue, Y. Kouno, H. Kawai and S. Yokomizo, A Speed-enor-le vector control method of parallel-connected dual induction motor fed by a ingle inverter, IEEE Tran. Indutry Application, vol. 38, pp , Nov./Dec. 22. [7]. Maurizio Cirrincione, Marcello Pucci, Gianalvo Cirrincione and Gérard-André Capolino, An Adaptive Speed Oberver Baed on a New Total Leat-Square Neuron for Induction Machine Drive, IEEE Tran. Indutry Application, vol. 42, no. 1, pp.89-14, January/February 26. [8]. Luigi Salvatore, Silvio Stai, and Lea Tarchioni, A new EKF-baed algorithm for flux etimation in induction machine, IEEE Tran. Indutrial Electronic, vol.4, no.5, pp , October [9]. Y.R. Kim, S.K. Sul and M.H. Park, Speed enorle vector control of induction motor uing Extended Kalman Filter, IEEE Tran. Indutry Application., vol. 3, no. 5, pp , September / October [1]. H.W. Kim and S.K. Sul, A New motor Speed Etimator Uing Kalman Filter in Low- Speed range, IEEE Tran. Indutry Application, vol. 43, no. 4, pp , Augut [11]. K. L. Shi, T. F. Chan, Y. K. Wong and S. L. Ho, Speed etimation of an induction motor drive uing an optimized Extended Kalman Filter, IEEE Tran. Indutrial Electronic, vol. 49, pp , Feb. 22. [12]. M. Barut, S. Bogoyan and M. Gokaan, Speed-enorle etimation for induction motor uing Extended Kalman Filter, IEEE Tran. Indutrial Electronic, vol. 54, no.1, pp , Feb. 27. [13]. M. Barut, S. Bogoyan and M. Gokaan, Experimental evaluation of Braided EKF for enorle control of induction motor, IEEE Tran. Indutrial Electronic, vol. 55, no.2, pp , Feb. 28. [14]. M. Tuji, Y. Umeaki, R. Nakayama, and K. Izumi, A Simplified MRAS baed enorle vector control method of induction motor, in proc. IEEE, 22, pp [15]. Mohamed Rahed, Fraer Stronach and Peter Va, A Stable MRAS-baed enorle vector control induction motor drive at low peed, in proc. IEEE, 23, pp [16]. R. Cardena, R. Pena, G. Aher, J. Clare and J. Carte, MRAS oberver for doubly fed induction machine, IEEE Tran. Energy Converion, vol.19, no.2, pp , June 24. [17]. M. Cirrincione, M. Pucci, G. Cirrincione and G. A. Capolino, A new TLS-baed MRAS peed etimation with adaptive integration for high- performance induction machine drive, IEEE Tran. Indutry Application, vol. 4, no.4, pp , July/Aug. 24. [18]. M. Cirrincione and M. Pucci, An MRAS-baed enorle high-performance induction motor drive with a predictive adaptive model, IEEE Tran. Indutrial Electronic, vol. 52, no.2, pp , April 25. [19]. S. R. Bowe, A. Sevinc and D. Holliday, New natural oberver applied to peed enorle DC ervo and induction motor, IEEE Tran. Indutry Application, vol. 51, no.5, pp , Oct. 24. [2]. J. Guzinki, M. Diguet, Z. Krzeminki, A. Lewicki and H. Abu-Rub, Application of peed and load torque oberver in high- peed train drive for diagnotic purpoe, IEEE Tran. Indutry Application, vol. 56, no. 1, pp , Jan

11 Implementation of Field Oriented Speed Senorle [21]. J. Guzinki and H. Abu-Rub, M. Diguet, Z. Krzeminki and A. Lewicki Speed and load torque oberver application in high peed train electric drive, IEEE Tran. Indutry Application, vol. 57, no. 2, pp , Feb. 21. [22]. Adnan Derdiyok, Speed-Senorle Control of Induction Motor Uing a Continuou Control Approach of Sliding-Mode and Flux Oberver, IEEE Tran. Indutry Application, vol. 52, no. 4, pp , Augut 25. [23]. C. Lacu and G.D. Andreecu, Sliding mode oberver and improved integrator with DCoffet compenation for flux etimation in enorle controlled induction motor, IEEE Tran. Indutrial Electronic, vol. 53, no.3, pp , Feb.26. APPENDIX NOMENCLATURE R, R r Stator and rotor reitance (Ω) repectively L, L r Stator and rotor elf inductance (H) repectively J Inertia of the motor load ytem. (Kg-m 2 ) i d i d V d τ r Rotor time contant φ dr σ Leakage co-efficient φ dr i q d-axi and q-axi tator current in tator reference frame (A) Etimated d-axi and q-axi tator current i q V q in tator reference frame (A) d-axi and q-axi tator voltage in tator reference frame (V) d-axi and q-axi rotor flux in tator reference (Wb) Etimated d-axi and q-axi rotor flux in tator reference frame (Wb) ˆ Repreent etimated value T L Load torque (Nm) A State matrix T L Etimated load torque (Nm) X State vector T e Electromagnetic torque developed (Nm) B Input matrix ω r Rotor angular velocity (rad/) V Input vector ω r Etimated rotor angular velocity (rad/) C Output matrix. n p No. of pole pair φ qr φ qr 737

12 R. Gunabalan, et al. R. Gunabalan obtained hi B.E. degree in Electrical and Electronic Engineering from Manonmanium Sundaranar Univerity, Tirunelveli, TamilNadu in 2 and M.Tech. degree in Electrical Drive and Control from Pondicherry Univerity in 26. He did hi Ph.D from Anna Univerity, Chennai, TamilNadu in 215. He i working a an Aociate Profeor in the School of Electrical and Electronic Engineering, VIT Univerity-Chennai, TamilNadu, India. He ha publihed / preented around 3 paper in National and International Journal / Conference. Hi reearch interet are in the area of dc-dc power converter and etimation and control of induction motor drive. He i a life member of ISTE and a member of IEEE. V. Subbiah obtained hi BE (Electrical) degree from Madra Univerity, India in 1965, ME (Control Sytem) from Calcutta Univerity in 1968 and PhD (Power Electronic) from Madra Univerity in He ha been aociated with Technical Education for more than four decade. He worked at PSG College of Technology, Coimbatore, India in variou capacitie and retired in May 2. Then, he joined the Faculty of Engineering, Multimedia Univerity, Malayia in June 2 on a contract appointment for two year. After returning to India, he joined Sri Krihna College of Engineering and Technology, Coimbatore in Augut 22 a the Dean of Electrical Science and continued in that capacity till 213. Currently, he i working a a viiting profeor at PSG College of Technology, Coimbatore. Dr Subbiah ha taught undergraduate a well a potgraduate coure for more than 4 year. He ha publihed / preented around 8 paper in National and International Journal / Conference. He i a Senior Member of IEEE (USA), a Fellow of the Intitution of Engineer (India), and a Life Member of Indian Society for Technical Education. Hi area of interet include Power Electronic, Electrical Drive and Control Sytem. 738