AU2021100849A4 - An advanced predictive flux control for induction motor drive - Google Patents
An advanced predictive flux control for induction motor drive Download PDFInfo
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- AU2021100849A4 AU2021100849A4 AU2021100849A AU2021100849A AU2021100849A4 AU 2021100849 A4 AU2021100849 A4 AU 2021100849A4 AU 2021100849 A AU2021100849 A AU 2021100849A AU 2021100849 A AU2021100849 A AU 2021100849A AU 2021100849 A4 AU2021100849 A4 AU 2021100849A4
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- induction motor
- motor drive
- voltage vectors
- flux
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/34—Modelling or simulation for control purposes
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/14—Estimation or adaptation of machine parameters, e.g. flux, current or voltage
- H02P21/141—Flux estimation
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/14—Estimation or adaptation of machine parameters, e.g. flux, current or voltage
- H02P21/143—Inertia or moment of inertia estimation
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/24—Vector control not involving the use of rotor position or rotor speed sensors
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/06—Arrangements for speed regulation of a single motor wherein the motor speed is measured and compared with a given physical value so as to adjust the motor speed
Abstract
Our invention "An advanced predictive flux control for induction motor drive "is a
Predictive flux control (PFC) is one of finite control set model predictive control
(FCS MPC) used for adjustable speed operation of induction motor drive. The
objective function of this control technique is defined with stator flux as a single
control objective AND The reference stator flux used in the objective function is
expressed as the function of reference torque. As a result, the issue of weighting
factor selection of FCSMPC is eliminated. however, the number of computations
required for the PFC is very high as all the voltage vectors of the 2-level inverter
will be used for required predictions. To address this problem, limited voltage
vectors are selected based upon the stator flux location and quadrant of operation
of the drive. Hence, the required number of computations required for predictions
and objective function optimization can be reduced by 50 % compared to
conventional approach. In this work, a simplified approach of PFC is presented
with selective voltage vectors based on operating conditions of induction motor
drive. The detailed implementation of the proposed concept is presented with
supportive simulation results.
10
* r e Op S t
0r -
s Cost e Reference - -W Fncin3(
r * transformation Optmiztion
L3M,
k+1 k +1 2-Level VSI sa s
Qua.dran..t Optimal (, Stator Flux sRtrFu Transformation
() -- of - voltage and and
Operation VectorscEsiaonTaf
atn
Figure.1HPredictive fluxcontrolofinductionmotordrive
Sector-II t Sector-II
u?(010) I u,( 10)
Sector-IV - Sector-I
n( AP 000
SectorIII Setorc1
u4 (011) -- ' dI tIIu(100
us (0 10) u,( 01)
Sector-V Sector-VI
Figure.2 Location of 2-level VSI voltage vectors in complex plane
Description
* r e Op t S 0r - e Reference - s-W Fncin3( Cost Optmiztion L3M, r * transformation
k+1 k +1 2-Level VSI sa s
Qua.dran..t Optimal (, Stator Flux sRtrFu Transformation () -- of - voltage and and
Operation VectorscEsiaonTaf atn
Figure.1HPredictive fluxcontrolofinductionmotordrive
Sector-II t Sector-II u?(010) I u,( 10)
SectorIII Setorc1 Sector-IV - Sector-I n( AP 000 u4 (011) -- ' dI tIIu(100
us (0 10) u,( 01) Sector-V Sector-VI
Figure.2 Location of 2-level VSI voltage vectors in complex plane
An advanced predictive flux control for induction motor drive
Our invention "An advanced predictive flux control for induction motor drive" is related to a finite control set model predictive control technique used for 2-level voltage source inverter fed induction motor for adjustable speed applications. This technique works well for all the four quadrant operations of the induction motor driven by a 2-level voltage source inverter.
An electric motor converts electrical power with certain voltage or current magnitude and frequency to the mechanical power at corresponding speed and torque. In many of the industrial applications power electronic converter fed electric motors will be used for adjustable speed operation and the combination of electrical source, power electronic converter and electric motor is known as electric drive. Traditionally, DC motor drives were used for adjustable speed operation and induction motors were used for constant speed applications. After the advancement in power electronic converter technologies and digital control platforms, the usage of induction motor drives became popular for their numerous advantages(1).
The major control techniques used for voltage source inverter which is used to drive induction motor for adjustable speed applications are scalar control technique, field-oriented control technique (FOC) and direct torque control (DTC)(2-5). However, FOC and DTC are the control techniques adopted for fast dynamic response. Each of the above control technique is having their own advantages and disadvantages. However, DTC control structure is simple compared to FOC and moreover direct control over torque and stator flux can be achieved(5).
Recently, conventional linear (PI) controllers and nonlinear (hysteresis) controllers are being replaced by model based predictive controllers in various control techniques used for different power electronic converter-based applications(6).
One of such popular control techniques used for induction motor drive is predictive torque control (PTC)(7). This control technique uses the concept of finite control set model predictive control which is presented in (8,9). The detailed implementation of PTC was well documented in (7,10,11).
Predictive torque control (PTC) is an effective alternative for direct torque control (DTC) of induction motor in adjustable speed drive applications. The major concern with PTC is the selection of weighting factor for the stator flux term in the objective function. To avoid the weighting factor selection, a modified objective function was introduced as stator flux is the only control objective and it is known as predictive flux control (PFC)(12,13).
On the other hand, to reduce the computational complexity in predictive control techniques, few methods were reported in the literature with different approaches(10-12). In (14), the selection of the switching states were selected based on the stator current location in the complex plane and operating mode of the drive. By considering the key points from the above works, a simplified PFC was proposed for an induction motor drive based on the location of the stator flux in the complex plane and drive operating mode.
1. Mohan N, Raju S. ANALYSIS AND CONTROL OF ELECTRIC Simulations and Laboratory Implementation. Wiley; 2021. 2. Takahashi I, Noguchi T. A New Quick-Response and High-Efficiency Control Strategy of an Induction Motor. IEEE Trans Ind Appl [Internet]. 1986 Sep
[cited 2014 Aug 18];IA-22(5):820-7. Available from: http://ieeexplore.ieee.org/xpls/abs-all.jsp?arnumber=4504799 3. Takahashi I, Ohmori Y. High-Performance Direct Torque Control of an Induction Motor. IEEE Trans Ind Appl. 1989;25(2):257-64. 4. Kubota H, Matsuse K. Speed sensorless field-oriented control of induction motor with rotor resistance adaptation. IEEE Trans Ind Appl. 1994;30(5):1219-24. 5. Casadei D, Profumo F, Serra G, Tani A. FOC and DTC: Two Viable Schemes for Induction Motors Torque Control. IEEE Trans Power Electron. 2002 Sep;17(5):779-87. 6. Cort6s P, Kazmierkowski MP, Kennel RM, Quevedo DE, Rodriguez J. Predictive Control in Power Electronics and Drives. IEEE Trans Ind Electron. 2008 Dec;55(12):4312-24. 7. Rodriguez J, Kennel RM, Espinoza JR, Trincado M, Silva CA, Rojas CA. High Performance Control Strategies for Electrical Drives: An Experimental Assessment. IEEE Trans Ind Electron. 2012 Feb;59(2):812-20. 8. Rodriguez J, Kazmierkowski MP, Espinoza JR, Zanchetta P, Abu-rub H, Young HA, et al. State of the Art of Finite Control Set Model Predictive Control in Power Electronics. IEEE Trans Ind Informatics. 2013 May;9(2):1003-16. 9. Kouro S, Cort6s P, Vargas R, Ammann U, Rodriguez J. Model Predictive
Control - A Simple and Powerful Method to Control Power Converters. IEEE Trans Ind Electron. 2009 Jun;56(6):1826-38. 10. Wang F, Zhang Z, Kennel R, Rodriguez J. Model predictive torque control with an extended prediction horizon for electrical drive systems. Int J Control. 2015 Jul;88(7):1379-88. 11. Habibullah M, Lu DD-C, Xiao D, Rahman MF. A Simplified Finite-State Predictive Direct Torque Control for Induction Motor Drive. IEEE Trans Ind Electron [Internet]. 2016 Jun;63(6):3964-75. Available from: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=738663 7 12. Muddineni VP, Sandepudi SR, Bonala AK. Simplified finite control set model predictive control for induction motor drive without weighting factors. IEEE Int Conf Power Electron Drives Energy Syst PEDES 2016. 2017;2016 Janua(2):1-6. 13. Zhang Y, Yang H. Model-Predictive Flux Control of Induction Motor Drives with Switching Instant Optimization. IEEE Trans Energy Convers. 2015 Sep;30(3):1113-22. 14. Sahin I, Keysan 0. A new model predictive torque control strategy with reduced set of prediction vectors. Proc - 2018 IEEE 12th Int Conf Compat Power Electron Power Eng CPE-POWERENG 2018. 2018;1-6. 15. CN110350837A Simplified alternative finite state set model predictive direct
torque control method.
16. CN111092581A Model predictive control method with variable control
period.
17. CN107171587A Improved finite set model prediction control method suitable
for inverter.
18. CN107453627A Fixed frequency control method of finite set model prediction
control.
1. The objective of the invention is to design simplified predictive flux control (PFC) for 2-level voltage source inverter fed induction motor drive used for adjustable speed operation. 2. The other objective is to eliminate the weighting factor selection in the objective function by considering stator flux being the control objective in the control technique. 3. The other objective of the invention is to limit the number of candidate voltage vectors to reduce the computational burden.
4. The other objective of the invention is to maintain the satisfactory operating conditions during all the operating modes (i.e., FM,RM,FB and RB) of the drive. 5. The other objective of the invention is to select the appropriate candidate voltage vectors to address the previous objective. 6. The other objective of the invention is to maintain the decoupled control over torque and stator flux.
The following claims were made in the proposed work
1. Selection of suitable voltage vectors based on mode of operation and stator flux location.
2. The computational burden is reduced 50% for the required predictions and objective function optimization.
3. Weighting factor selection can be eliminated in this approach.
4. Drive is running with satisfactory operating conditions.
Example embodiments of present invention presents the physical structure of the basic induction motor drive arrangement used with DTC/PTC will not be effected with the proposed control technique.
Example embodiments of present invention presents the simplified predictive flux control for voltage source inverter fed induction motor drive.
Example embodiments of the present invention eliminates the weighting factor selection and associated problems in the objective function of predictive control techniques used for converter fed drives applications. Further, the selected weighting factors may not be optimal for all the operating conditions of the drive.
Example embodiments of the present invention reduces the number of computations required for the predictions and objective function optimization by limiting the number of candidate voltage vectors from eight to four. Therefore, % of total computations will be reduced for required predictions and objective function optimization.
Example embodiments of the present invention selects the appropriate candidate voltage vectors are selected for different operating modes of the drive. Further, suitable zero voltage vector is used to limit the number of switching transitions.
Example embodiments of the present innovation gives the decoupled control over torque and stator flux.
Figure.1 Predictive flux control of induction motor drive Figure.2 Location of 2-level VSI voltage vectors in complex plane Figure.3 Identification of operating mode of induction motor drive Figure.4 Steady state operation of the drive with 150 rad/s speed and 8 N-m load. Figure.5Dynamic load change for the drive with T = 0 to 8 N-m Figure.6Different modes of operation of the drive
Predictive Flux Control: Implementation of PFC requires the mathematical model of induction motor for the estimation and prediction of control objectives. The model of the induction motor with Osand is as state variables can be expressed as
dVLdt F L0 A,,ILV 1(1) di,/Idt _| = A. A2_2] _ B)
' T= 3/2p Im(Vi) (2)
Jdo,/dt = T - (3)
Where An= -R,
An= A (R-jLmr), A22= - A ( RsL,+ RrLs)+ jcor, Bl= A Lr, A= 1/ (Ls Lr-Lm 2 )
In this representation us, is,ys, Rs and Ls are the stator parameters ir,fr,Rrand Lr are the rotor parameters and Lmis the mutual inductance, wrisrotor speed. Teand Tlare the electromagnetic torque and load torque, respectively. J and p are the moment inertia and pole pairs of the induction motor. The implementation of predictive control technique involves estimation and prediction of control objectives for objective function optimization. The implementation diagram is shown in the Figure.1. Estimation of stator flux and rotor flux for the present sampling period (k) can be obtained by using the Euler's discretization for the above represented mathematical model of induction motor. k k-I 5 T (Ai- +) (4) Y1'k=(L/Lj)y (/AL)i (5)
Based on the estimated values, prediction of stator current, stator flux and rotor flux can be obtained from (6)-(8) for the predefined voltage vectors presented in Table 1.
=k 1 +T ( Agk+ A + B, (u (7) 1
+= +(R(L/ L,)i-((R/L)-j)) (8)
Where m represents the set of selected voltage vectors. In each sampling period, four voltage vectors are selected instead of eight voltage vectors. The selection of voltage vectors depends on the location of stator flux and operating mode of the drive. The location of all the voltage vectors in complex plane are depicted in Figure 2. In this representation, total plane is divided in to six equal sectors. Each sector contains an active vector which is displaced by /3 rad with respect to adjacent active vector and null vectors are located at the center of the complex plane. To identify the sector number p which contains the stator flux vector can be obtained by using following relations. 0, = arctan(V/ /V) (9) (2N-3) r/6 !p (N) (2N-1) r/6 (10) Where N= 1,...6
Table.1 Selected voltage vectors for predictions
Mode/Sector FM RM FB RB I U2U3UO UsU6UIUO U2U3U4U7 U4U5U6U7
II u2U3U4U7 U6UIU2U7 U3U4U5UO UsU6UIUO
III U4 U5 UO U U2 U3 UO U4 U U6 U7 U6 U U2 U7
IV U4UsU6U7 U2U3U4U7 U5U6UIUO UU2U3UO
V UU6UIUO U3U4U5UO U6UIU2U7 U2U3U4U7
VI U6UIU2U7 U4UsU6U7 UU2U3UO U3U4U5UO
The mode of the drive will be identified based upon the motor operating conditions and it is shown in Figure 3. Here, the low speed is selected as 10% of the rated speed. Where FM= Forward Motoring RM= Reverse Motoring FB= Forward Braking
RB= Reverse Braking After prediction of control objectives with the above predefined voltage vectors, objective function defined with stator flux control objective. The reference stator flux required for this objective function is obtained by using below relations. Initially, the reference stator flux is selected as follows for below rated speed operation of the induction motor.
The torque can be expressed as the cross product of stator flux and rotor flux as follows.
T =1.5pAL (V, &V) (12)
From the above equation, if the estimated rotor flux is available, the following relation should be satisfied.
T'=1.5pAL,(yy ) (13)
Now, the reference stator flux vector based on (11) and (13) can be expressed as follows.
y = exp(jZ y) (14)
Z/ ZV + arcsin(T* 1.5pAL,, '| [(15
) By using (6) and (14), an objective function is expressed as follows.
C= f- (16) By minimizing the above objective function appropriate optimal voltage vector will be selected for the next sampling period.
Results: The proposed control algorithm is implemented in MATLAB/Simulink environment for 2.2 kW, 2-level VSI fed induction motor. The control algorithm is implemented for a sampling period of 50 ps. The results are given for steady state in Figure.4, dynamic load response in Figure Sand all possible quadrant of operations in Figure.6. The waveforms in each result are given for rotor speed, stator current, torque and stator flux. From all these results, it is evident that the proposed algorithm is giving satisfactory operating conditions of the drive. However, a small deviation in stator flux and torque can be observed during the mode transition from braking to motoring mode.
Claims (6)
1. Our invention "An advanced predictive flux control for induction motor drive" is a predictive flux control (PFC) is one of finite control set model predictive control (FCS MPC) used for adjustable speed operation of induction motor drive. The objective function of this control technique is defined with stator flux as a single control objective. The reference stator flux used in the objective function is expressed as the function of reference torque. As a result, the issue of weighting factor selection of FCSMPC is eliminated. however, the number of computations required for the PFC is very high as all the voltage vectors of the 2-level inverter will be used for required predictions. To address this problem, limited voltage vectors are selected based upon the stator flux location and quadrant of operation of the drive. Hence, the required number of computations required for predictions and objective function optimization can be reduced by 50
% compared to conventional approach. In this work, a simplified approach of PFC is presented with selective voltage vectors based on operating conditions of induction motor drive. The detailed implementation of the proposed concept is presented with supportive simulation results.
2. According to claims# the invention is to a predictive flux control (PFC) is one of finite control set model predictive control (FCS MPC) used for adjustable speed operation of induction motor drive and the objective function of this control technique is defined with stator flux as a single control objective AND The reference stator flux used in the objective function is expressed as the function of reference torque.
3. According to claim,2# the invention is to a result, the issue of weighting factor selection of FCSMPC is eliminated. however, the number of computations required for the PFC is very high as all the voltage vectors of the 2-level inverter will be used for required predictions.
4. According to claim,2,3# the invention is to address this problem, limited voltage vectors are selected based upon the stator flux location and quadrant of operation of the drive and the required number of computations required for predictions and objective function optimization can be reduced by 50 % compared to conventional approach.
5. According to claim,2,4# the invention is to a simplified approach of PFC is presented with selective voltage vectors based on operating conditions of induction motor drive.
6. According to claiml,2,3,5# the invention is to the detailed implementation of the proposed concept is presented with supportive simulation results.
Figure.1 Predictive flux control of induction motor drive
Figure.2 Location of 2-level VSI voltage vectors in complex plane
Figure.3 Identification of operating mode of induction motor drive
Figure.4 Steady state operation of the drive with 150 rad/s speed and 8 N-m load.
Figure.5 Dynamic load change for the drive with Tl = 0 to 8 N-m
Figure.6 Different modes of operation of the drive.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112054512A (en) * | 2020-08-20 | 2020-12-08 | 三峡大学 | FCS-MPC control-based high-permeability active power distribution network power quality management method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112054512A (en) * | 2020-08-20 | 2020-12-08 | 三峡大学 | FCS-MPC control-based high-permeability active power distribution network power quality management method |
| CN112054512B (en) * | 2020-08-20 | 2022-04-08 | 三峡大学 | FCS-MPC control-based high-permeability active power distribution network power quality management method |
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