Field-oriented control of five-phase induction motor with open-end stator winding

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1 ARCHIVES OF ELECTRICAL ENGINEERING VOL. 6(3), pp (216) DOI 1.11/aee Field-oriented control of five-phase indction motor with open-end stator winding JACEK LISTWAN, KRZYSZTOF PIEŃKOWSKI Wroclaw University of Technology Department of Electrical Machines, Drives and Measrements Wybree Wyspianskiego 27, -37 Wrocław, Poland (Received: , revised: ) Abstract: The mathematical model of the five-phase sqirrel-cage indction motor and the system of the dal five-phase voltage sorce inverter have been presented. The control methods and control systems of the field-oriented control of the five-phase indction motor with an open-end stator winding are described. The strctres of the direct fieldoriented control system (DFOC) and the Indirect Field-oriented control system (IFOC) with PI controllers in oter and inner control loops are analyed. A method of space vector modlation sed to control the system of the dal five-phase voltage sorce inverter has been discssed. The reslts of simlation stdies of the field-oriented control methods are presented. Comparative analysis of the simlation reslts was carried ot. Key words: analysis, field-oriented control, five-phase indction motor, open-end winding, simlation stdies, space-vector modlation 1. Introdction Nowadays three-phase sqirrel cage indction motors are widely sed in the indstrial drive systems. In recent years, there is a great interest in sing the constrctions of sqirrelcage indction motors with the nmber of phases of the stator winding greater than three. Motors of this design are called mlti-phase motors [2, 4-9]. Mlti-phase sqirrel-cage indction motors have a lot of advantages in comparison to conventional three-phase indction motors [2, 4-9]. The nominal vales of the phase crrents in mlti-phase systems are smaller than the nominal vales of the phase crrents in the threephase systems with the same power ratings. Other beneficial properties of the mlti-phase indction motors inclde: redction of the amplitdes of plsating components of the motor electromagnetic torqe, redction of losses cased by higher harmonics of motor crrents and redction of the amplitde of the crrent harmonics in the dc link of freqency converter. In addition, the mlti-phase indction motors allow to ensre greater reliability of the drive Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

2 396 J. Listwan, K. Pieńkowski Arch. Elect. Eng. systems. Motors with a phase nmber greater than three may be operated conditionally at failre of one or more phases of the stator windings. Development of freqency converter control systems provides the possibility of indstrial applications of these types of motors. Power freqency converters can be bilt for a larger nmber of phases dring powering from the three phase mains. Indction motors with an open-end stator winding with dal-inverter spply have been extensively investigated for varios applications, for example series hybrid power vehicles and falt-tolerant drives. The topology is simple to realie while offering a higher nmber of switching states in comparison to standard converters and allows to increase the accracy of control [1, 3, 1]. The control strctres of the mlti-phase indction motor with an open-end stator winding allow to generate voltage waveforms, which are comparable with voltage waveforms obtained from mltilevel inverters. In this paper the theoretical analysis and simlation research were performed for the control systems of the five-phase indction motor with an open-end stator winding. The openend stator winding of the motor is fed and controlled by the system which consists of two voltage sorce inverters, connected to the beginnings and the ends of five-phase stator winding terminals. 2. Mathematical model of five-phase indction motor The mathematical model of the five-phase sqirrel-cage indction motor has been formlated on the basis of commonly sed simplifying assmptions [2, 4, 8]: a mlti-phase stator and rotor phase windings are considered as concentrated, a motor magnetic circit is linear, the effects of eddy crrents and iron losses are neglected, the vales of parameters and variables of the rotor phase winding are converted to the stator winding side. The mathematical model of the five-phase indction motor is described by differential eqations with coefficients changing as a fnction of the angle of rotor rotation. Eqations with constant coefficients can be obtained by the se of sitable power invariant transformations of the stator and rotor phase variables. The non-power-invariant forms of transformation matrices for stator and rotor phase variables are presented in detail in [4-9]. The stator and rotor phase variables of the five-phase indction motor can be transformed to new variables considered in the transformed coordinate systems: the x-y coordinate system, which rotates at arbitrary anglar speed ω k (in case ω k = the stationary coordinate system is denoted as α-β), the additional coordinate system 1-2 and the system of ero components. The eqations of the five-phase indction motor after transformation take the following form [4-9]: the voltage eqations of the stator and rotor in the x-y coordinate system, which rotates at arbitrary anglar speed ω k : sx sy = R i ω ψ + pψ (1) s s sx sy k k sy sx sx, = R i + ω ψ + pψ (2) sy, Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

3 Vol. 6 (216) Field-oriented control of five-phase indction motor with open-end stator winding 397 ( ω ω ) ψ + pψ, Rr irx k e ry rx = (3) ( ω ω ) ψ + pψ, Rr iry + k e rx ry = (4) the stator voltage eqations in the additional coordinate systems 1-2: = Rs is1 + pψ 1, () s1 s = Rs is2 + pψ 2, (6) s2 s the eqation of motor electromagnetic torqe: T e ( 2) p ( ψ i ψ i ) = ( 2) p ( ψ i ψ i ), = (7) b sy rx sx ry b ry sx rx sy where: sx, sy, s1, s2 are components of the stator voltage vectors in the x-y and 1-2 systems; i sx, i sy, i s1, i s2, i rx, i ry are components of the stator and rotor crrent vectors in the x-y and 1-2 systems; ψ sx, ψ sy, ψ s1, ψ s2, ψ rx, ψ ry are components of the stator and rotor flx linkage vectors in the x-y and 1-2 systems; ω k is the arbitrary anglar speed of the coordinate system relative to the stator; ω e is the electrical anglar speed of the motor; T e is the motor electromagnetic torqe; R s, R r are the stator and rotor phase resistances; p b is the nmber of motor pole pairs; p = d/dt is the derivative operator. In the above system the eqations for stator and rotor ero components and the rotor voltage eqations in the additional coordinate systems 1-2 are omitted, becase they are identically eqal to ero. 3. Mathematical model of the system of dal five-phase voltage sorce inverter The scheme of the five-phase sqirrel-cage indction motor with the open-end stator winding spplied by the dal five-phase voltage sorce inverter is shown in Fig 1. The dal fivephase voltage sorce inverter consists of two conventional five-phase voltage sorce inverters. The individal inverters and their elements are marked by indices 1 and 2. The inverter legs are denoted with capital letters A, B, C, D, E and the netral points of the two dc links are identified as N1 and N2. The machine stator phases are labeled as a, b, c, d and e [1, 3, 1]. It is assmed that the both inverters are spplied from separate ideal DC voltage sorces and that the voltage vales d1 and d2 are the same for the two inverters. In the case of a two-level voltage sorce inverter, each inverter branch consists of two power electronics keys operated alternately. Each branch of the inverter can be presented as a binary switch, assming an ideal operation of the voltage sorce inverters keys. The phase voltages of the stator winding can be described as: sa sb = A1N 1 + N1N 2 A2N 2, (8) = B1N1 + N1N 2 B2N 2, (9) Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

4 398 J. Listwan, K. Pieńkowski Arch. Elect. Eng. sc = C1N1 + N1N 2 C 2N 2, (1) sd = D1N1 + N1N 2 D2N 2, (11) se = E1N1 + N1N 2 E 2N 2. (12) Fig. 1. Five-phase indction motor with open-end stator winding spplied by two voltage sorce inverters The voltage space vectors generated by the inverter 1 and 2 expressed in the stationary rectanglar coordinate systems α-β and in the system 1-2 can be determined in general form: αβ i = α i + jβ i = ( AiNi + abini + a CiNi + a DiNi + a EiNi ), (13) i = 1i + j2i = ( AiNi + a BiNi + a CiNi + a DiNi + a EiNi ), (14) where: i = 1, 2; a = exp( j2π /). The stator voltage space vectors of the five-phase indction motor with the open-end winding in the coordinate systems α-β and 1-2 are eqal to the difference of the corresponding otpt voltage space vectors of individal inverters. This condition can be described by the following formlas: s αβ = (1) αβ1, αβ 2. s = (16) Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

5 Vol. 6 (216) Field-oriented control of five-phase indction motor with open-end stator winding 399 All otpt voltage vectors generated by individal five-phase voltage sorce inverters are presented in Fig. 2 [4]. Voltage vectors designated in coordinate system α-β are shown in Fig. 2a and voltage vectors designated in coordinate system 1-2 are shown in Fig. 2b. a) Sector Sector 6 Sector β Sector Sector Sector 1 α Sector Sector 7 3 Sector 9 Sector 8 Fig. 2. Voltage space vectors generated by five-phase voltage sorce inverter: a) in coordinate system α-β; b) in coordinate system 1-2 All otpt voltage space vectors generated by the five-phase voltage sorce inverter considered in coordinate systems α-β and 1-2 can be divided into thirty active vectors and two ero vectors. Thirty active voltage space vectors can be divided into three grops taking into accont the length of the vector: 1 long vectors, 1 medim vectors and 1 short vectors. In Fig. 2 the ero voltage vectors were marked with the nmbers and 31 and the active voltage vectors were marked with the nmbers from 1 to 3. The decimal nmber specifying the nmber of voltage vector can be converted into a -position nmber in the binary system. The binary bits determine states of the switches in the sitable legs of the five-phase voltage sorce inverter. Voltage vectors in coordinate system 1-2 are not involved in the generation of the motor electromagnetic torqe, bt they can case enlargement of the amplitde of the stator phase crrents and the power losses in the stator windings. 4. Space vector modlation method Space vector modlation (SVM) is widely sed for the control of voltage sorce inverters with three-phase indction motors. This modlation techniqe can be also implemented for the control of the dal system of the five-phase voltage sorce inverters, sed for the five-phase indction motor with an open-end stator winding. Bt there are some difficlties in the application of the principle of the space vector modlation to mltiphase inverters. For example, in the five-phase inverter there are 2 = 32 voltage space vectors as illstrated in Fig. 2. De to a great nmber of generated voltage space vectors it is not practical for sing all these voltage vectors in the modlation techniqe. For this reason in the system of the dal five-phase voltage sorce inverter sed for the five-phase indction motor with an open-end stator winding the modified concept of conventional modlation has been adopted. Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

6 4 J. Listwan, K. Pieńkowski Arch. Elect. Eng. The block diagram of the space vector modlation method sed to control the system of the dal five-phase voltage sorce inverter is shown in Fig. 3 [1, 3]. Two space vector modlators: SVM 1 and SVM 2 are sed in this control strctre. The vale of the reference stator voltage space vector sref is mltiplied by. and!.. It means, that the reference stator voltage vector is divided into two reference voltage vectors 1ref, 2ref with opposite directions and two times smaller magnitdes. These two new reference voltage vectors are applied to individal space vector modlators and are synthesied by the selection of the appropriate voltage space vectors of individal inverters and the dwell times. d VSI 1 S A1 A1N1 sref. 1ref SVM 1 S B1 S C1 S D1 S E1 B1N1 C1N1 D1N1 E1N1 S A2 A2N2 -. 2ref SVM 2 S B2 S C2 S D2 S E2 B2N2 C2N2 D2N2 E2N2 VSI 2 d Fig. 3. Block diagram of the space vector modlation method sed to control the system of the dal five-phase voltage sorce inverter The space vector modlation of each inverter has been based on the synthesis of the reference voltage vector by sing the appropriate switching times of two long and two medim inverter voltage vectors, chosen from the same sector in which the reference voltage vector is located and sing additionally two ero voltage vectors. Graphical interpretation of the space vector modlation method sed for SVM 1 and SVM 2 is shown in Fig. 4. a) Im 24 Sector1 Re 6 1 α 29 1ref Sector 6 π π α 16 2 Re 2ref 7 2 Im Fig. 4. The principle of determining the reference voltage vector with the choice of long and medim inverter voltage vectors: a) for SVM 1; b) for SVM 2 Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

7 Vol. 6 (216) Field-oriented control of five-phase indction motor with open-end stator winding 41 For example, when reference voltage vector 1ref falls into Sector 1, as shown in Fig. 4a it can be synthesied by for adjacent active vectors and two ero vectors. The two adjacent long voltage vectors: 2, 24, two adjacent medim voltage vectors: 16, 29 and two ero voltage vectors:, 31 are selected for modlation. For the reference voltage vector 2ref sitated in Sector 6, as shown in Fig. 4b it can be also synthesied by for adjacent active vectors and two ero vectors. The two adjacent long voltage vectors: 6, 7, two adjacent medim voltage vectors: 1, 2 and two ero voltage vectors:, 31 are selected for modlation. For the case when the reference voltage vectors are located in sector 1 and 6, the principle of the space vector modlation method for SVM 1 and SVM 2 can be described by the eqations: a) for SVM 1: b) for SVM 2: 1ref s 2 al 24 bl 16 am 29 bm 2 31 t T = t + t + t + t + t + 2, (17) 2ref s 6 al 7 bl 1 am 2 bm 2 31 t T = t + t + t + t + t + 2. (18) Besides the generation of two above described reference voltage vectors in the α-β coordinate system, the reference voltage vectors which are eqal to ero in the 1-2 coordinate system were also generated. Switching times of individal voltage vectors are calclated according to the eqations [1]: t t bl t bm al ( 2 / ) sin( s π / ) ( ) T, = 2sin π α sref d s (19) ( 2 / ) sin[ α ( s 1) / ] ( ) T, = 2sin π π sref d s (2) t am ( /) sin( s π / ) ( sref d ) T, ( / ) sin[ α ( s 1) / ] ( ) T, = 2sin π α s (21) = 2sin π π sref d s (22) t = T t t t t s al am bl bm, (23) where: t al, t bl are switching times of long voltage vectors; t am, t bm are switching times of medim voltage vectors; t is the switching time of ero voltage vectors; sref the magnitde of the reference voltage vector; T s is a switching period; α is the angle position of reference voltage vector; s is a sector nmber (s = 1,, 1).. Field-oriented control systems In this paper the methods of rotor field oriented control of the five-phase indction motor with an open-end stator winding are considered. The rotor field oriented control systems can be generally classified into Direct Field-Oriented Control (DFOC) and Indirect Field-Oriented Control (IFOC). Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

8 42 J. Listwan, K. Pieńkowski Arch. Elect. Eng. The block diagram of the Direct Field-Oriented Control system of the five-phase indction motor with an open-end stator winding is shown in Fig.. * ψ r ψ r γ ψ ψ r ψ r ψ r γ ψ Fig.. The Direct Field-Oriented Control system of five-phase indction motor with open-end stator winding To implement the DFOC scheme the estimator of the instantaneos magnitde of the rotor flx vector and the instantaneos angle of the rotor flx vector has been sed. The estimator is based on the measred stator phase crrents and motor anglar speed. In the control scheme two oter control loops are applied: the control loop for motor anglar speed and the control loop for magnitde of the rotor flx vector. In the speed control loop the reference motor speed is compared with the actal motor speed and the error signal is given to the PI controller. An otpt signal from the PI controller is the reference vale of the y component of the stator crrent vector which is responsible for electromagnetic torqe control. In the flx control loop the reference magnitde of rotor flx is compared with the estimated magnitde of rotor flx and the otpt signal is given to the PI flx controller. An otpt signal from this PI controller is the reference vale of the x component of the stator crrent vector which is responsible for the rotor flx control. Then the reference vales of x and y components of the stator crrent vector are compared with the transformed vales of measred stator phase crrents and the error signals are given to the inner PI controllers. Reference vales of the stator voltage vector components determined by the PI controllers are transformed to the α-β coordinate system and afterwards given to the space vector modlators. Space voltage modlators set the switching states in the system of the dal five-phase voltage sorce inverter. The Indirect Field-Oriented Control system of the five-phase indction motor with an open-end stator winding is shown in Fig. 6. Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

9 Vol. 6 (216) Field-oriented control of five-phase indction motor with open-end stator winding 43 γ ψ γ ψ Fig. 6. The Indirect Field-Oriented Control system of the five-phase indction motor with an open-end stator winding To implement the IFOC scheme the angle of the rotor flx vector for field orientation is obtained by measring the motor speed and calclation of slip anglar freqency. In this control system the rotor slip freqency is calclated. The slip anglar freqency is added to the signal of the measred electrical anglar speed of the motor and the otpt vale is integrated in order to obtain the instantaneos angle position of the rotor flx vector. Three control loops are applied in this control system: the loop of motor speed control and the loops of x and y components of the stator crrent vector. In the loop of speed control the reference speed is compared with the actal speed of the five-phase indction motor and the error signal is given to the PI controller. The otpt signal from the PI controller is the reference vale of y component of the stator crrent vector which is responsible for electromagnetic torqe control. The reference vale of x component of the stator crrent vector is specified in accordance with the eqation: i sx * = ψ r /L m. The reference vales of x and y components of the stator crrent vector are compared with the transformed vales of measred stator phase crrents and the error signals are given to the PI controllers. Reference vales of the stator voltage components determined by the PI controllers are transformed to the α-β coordinate system and afterwards given to the space vector modlators. Space voltage modlators set the switching states in the system of the dal five-phase voltage sorce inverter. 6. Simlation reslts Simlation stdies were carried ot for the -phase sqirrel-cage indction motor with an open-end stator winding with the data and parameters: P N = 3 kw, U fn = 23 V, f N = H, p b Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

10 44 J. Listwan, K. Pieńkowski Arch. Elect. Eng. = 2, R s = 1 Ω, R r = 6.3 Ω, L ls =.4 H, L lr =.4 H, L m =.42 H. Simlation stdies were carried ot for two field-oriented control methods: Indirect Field Oriented Control (IFOC) and Direct Field Oriented Control (DFOC). The stdies of the indction motor with an open-end stator winding and dal converter system were performed for the assmed trapeoidal form of time changes of reference motor electrical speed. The step changes of load torqe were applied after transition to steady-state operation. The time waveforms of reference speed and electrical speed of the motor are shown in Fig Fig. 7. The waveforms of reference electrical speed ω er and electrical speed ω e of the five-phase indction motor with an open-end stator winding for field-oriented control methods: a) IFOC and b) DFOC It can be stated that for the considered operation the motor electrical speed ω e follows the reference electrical speed ω er with great accracy. The waveforms of the motor electromagnetic torqe and the load torqe for the two considered field-oriented control methods are presented in Fig. 8. The electromagnetic torqe of the indction motor has the vales eqal to the dynamic torqes dring start-p. In other operating states of the drive system the vales of the electromagnetic torqe are eqal to the load torqe. The waveforms of the flx component i sx and the torqe component i sy of the stator crrent vector of the five-phase indction motor with an open-end stator winding for the Indirect Field-Oriented Control method are presented in Fig. 9 and for the Direct Field-Oriented Control method in Fig. 1. It can be stated for both control methods that the flx component i sx of stator crrent vector is reglated at the nominal vale and that the torqe component i sy of the stator crrent vector has the vales proportional to the vales of the motor electromagnetic torqe. Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

11 Vol. 6 (216) Field-oriented control of five-phase indction motor with open-end stator winding 4 Fig. 11 shows the trajectories of the reference and the estimated vales of the magnitde of the rotor flx vector dring operation of the motor in the Direct Field Oriented Control strctre. It can be stated that the magnitde of the rotor flx vector is reglated at the nominal vale Fig. 8. The waveforms of the motor electromagnetic torqe T e and the load torqe T m of the five-phase indction motor with an open-end stator winding for field-oriented control methods: a) IFOC and b) DFOC Fig. 9. The waveforms of the components of stator crrent vector of the five-phase indction motor with an open-end stator winding for Indirect Field-Oriented Control: a) the reference i sxr and the actal i sx flx component; b) the reference i syr and the actal i sy torqe component Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

12 46 J. Listwan, K. Pieńkowski Arch. Elect. Eng Fig. 1. The waveforms of the components of stator crrent vector of the five-phase indction motor with an open-end stator winding for Direct Field-Oriented Control: a) the reference i sxr and the actal i sx flx component; b) the reference i syr and the actal i sy torqe component Fig. 11. Trajectory of the reference and the estimated magnitde of the rotor flx vector for Direct Field-Oriented Control of the five-phase indction motor with an open-end stator winding Fig. 12 shows the waveforms of stator phase voltage of the five-phase indction motor with an open-end stator winding. It has been observed that for the Indirect Field Oriented Control strctre and the Direct Field Oriented Control strctre the stator phase voltage have similar amplitde vales and time shapes. The waveforms of the stator phase crrent of the five-phase indction motor with an openend stator winding are shown in Fig. 13. The amplitdes of the stator phase crrent depend on the operation conditions of the drive system. The amplitdes have great vales in the dynamic states and fixed small vales at the steady-state operation. Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

13 Vol. 6 (216) Field-oriented control of five-phase indction motor with open-end stator winding Fig. 12. The time waveforms of the stator phase voltage of the five-phase indction motor with an open-end stator winding: a) IFOC and c) DFOC for the entire time of control system operation; b) IFOC and d) DFOC for the selected time period of control system operation The state variables obtained in the 1-2 coordinate system do not contribte to the electroagnetic torqe at all. A five-phase machine presents low impedance to this variables and it is therefore mandatory that the spply does not generate crrent components in the 1-2 cordinate system. This has been verified via simlation. Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

14 48 J. Listwan, K. Pieńkowski Arch. Elect. Eng. 1 is [A] Fig. 13. The waveforms of the stator phase crrent of the five-phase indction motor with an open-end stator winding: a) IFOC and c) DFOC for the entire time of control system operation; b) IFOC and d) DFOC for the selected time period of control system operation The waveforms of the stator crrent components in 1-2 system are shown in Fig. 14 for Indirect Field-Oriented Control of the five-phase indction motor with an open-end stator winding. The similar reslts were obtained for Direct Field-Oriented Control. As a reslt of the applied SVM strategy the amplitdes of the crrent vector components in the 1-2 coordinate system are very small and do not contribte to the performance of the motor. Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

15 Vol. 6 (216) Field-oriented control of five-phase indction motor with open-end stator winding Fig. 14. The waveforms of the components of the stator crrent vector in the 1-2 coordinate system for Indirect Field-Oriented Control of the five-phase indction motor with an open-end stator winding: a) i s1 and b) i s2 In the article the system of the five-phase indction motor with an open-end stator winding with two isolated DC power spplies was considered. The common mode voltage is of nonero vale bt the flow of ero seqence stator crrents is avoided. The simlation reslts confirmed also that the ero seqence stator crrent is eqal to ero. 7. Conclsions The mathematical models of the five-phase sqirrel-cage indction motor and the system of the dal five-phase voltage sorce inverter have been presented. The modified concept of space vector modlation has been applied for the control of the dal inverter system. In the space vector modlation system the long and middle inverter voltage vectors have been chosen for synthesiing of the reference voltage vector. The methods and control systems of Indirect Field-Oriented Control (IFOC) and Direct Field-Oriented Control (DFOC) of the five-phase indction motor with an open-end stator winding are described. Simlation stdies were carried ot for two field-oriented control methods: Indirect Field-Oriented Control Method and Direct Field-Oriented Control Method. The selected simlation reslts of the field-oriented control methods of the considered motor have been presented. The indction motor drive was tested for different load torqe conditions. The step changes of load torqe were applied after transition to steady-state operation. The measred motor speed follows the reference speed with great accracy. The electromagnetic torqe of Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM

16 41 J. Listwan, K. Pieńkowski Arch. Elect. Eng. the indction motor has a vale eqal to dynamic torqe dring start-p. In other operating states of the drive system the electromagnetic torqe is eqal to the load torqe. It has been observed that there was a rapid torqe response to mechanical load changes by sing the both field-oriented control methods. The amplitdes of stator phase crrents depend on the condition of the drive system: they have great vales in dynamic states and fixed small vales at the steady-state operation. It has been stated for the both control methods that the flx component i sx of stator crrent vector is reglated at the nominal vale and that the torqe component i sy of the stator crrent vector has the vales proportional to the vales of the motor electromagnetic torqe. The components of the stator phase crrent vector determined in the 1-2 coordinate systems have small amplitdes in the stdied states of the drive and these amplitdes are not dependent on the control strctre and have only a small contribtion to the performance of the stdied drive system. References [1] Jones M., Satiavan W., Levi E., A Five-Phase Mltilevel Space Vector PWM Algorithm for a Dal- Inverter Spplied Drive, Proc. of IECON 21-36th Annal Conference on IEEE Indstrial Electronics Society (21). [2] Levi E., Bojoi R., Profmo F., Toliyat H.A., Williamson S., Mltiphase indction motor drives a technology stats review, IET Electr. Power Appl., pp (27). [3] Levi E., Satiavan W., Bodo N., Jones M., A Space Vector Modlation Scheme for Mltilevel Open- End Winding Five-Phase Drives, IEEE Transactions on Energy Conversion 27(1): 1-1 (212). [4] Listwan J., Pieńkowski K., Analysis of Vector Control of Mlti-Phase Indction Motor, Zesyty Problemowe Masyny Elektrycne (Komel) 3: (214) (in Polish). [] Logan R., Aani J., Kasrl A., Tole S., Sndram R., Mohid H.J., Improved Torqe Control Performance of Direct Torqe Control for -Phase Indction Machine, International Jornal of Power Electronics and Drive Systems (IJPEDS) 3(4): (213). [6] Namhn K., Minhei K., Modified Direct Torqe Control System of Five Phase Indction Motor, Jornal of Electrical Engineering & Technology 4(2): (29). [7] Pieńkowski K., Analysis and control of dal stator winding indction motor, Archives of Electrical Engineering 61(3): (212). [8] Pieńkowski K., Analysis and Control of Mlti-Phase Sqirrel-Cage Indction Motor, Prace Nakowe Instytt Masyn, Napędów i Pomiarów Elektrycnych Politechniki Wrocławskiej 6: (211) (in Polish) [9] Renkadevi G., Rajambal K., Generalied Model of Mlti-Phase Indction Motor Drive sing Matlab/Simlink, Proc. IEEE PES Innovative Smart Grid Technologies India (211). [1] Somasekhar V.T., Reddy B.V., Sivakmar K., A For-Level Inversion Scheme for a 6n-Pole Open- End Winding Indction Motor Drive for an Improved DC-Link Utiliation, IEEE Transaction on Indstrial Electronics 61(9): (214). Broght to yo by Uniwersytet Technologicnego w Scecinie - Biblioteka Glówna Zachodniopomorskiego Download Date 1//16 11:9 AM