University of Miskolc Department of Automation. RUNTIME RECONFIGURATION OF AC DRIVE CONTROLLERS. Vásárhelyi József . Email: vajo@mazsola.iit.unimiskolc.hu. Details about the author.
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Department of Automation
Vásárhelyi József
Email: vajo@mazsola.iit.unimiskolc.hu
There are different approaches to define the reconfigurable systems [Brebner, Hauck, Luk, Maciejowski, Shirazi, Vuillemin].
Reconfigurable systems are usually considered those computing platforms whose architecture is modified by the software to suit the application at hand.
Most of Reconfigurable Computing Systems are plugin boards made for standard computers and they act as a Coprocessor attached to the main microprocessing unit.
There was demonstrated significant potential for the acceleration of computing in generalpurpose applications [Hauck, Smith, Villasenor, Vuillemin].
To treat the reconfiguration as a process one need a simple model for specifying and optimising designs, which contain elements that can be reconfigured at runtime.
Comparing to the number of applications known in the reconfigurable filed just a few of them are concentrated in the study of vector control for AC drives.
Vector control is a special field for digital signal processing.
There are known dedicated DSP processors for digital motor control and successful implementations of vector control [Beierke] are referred. The DSP implementation of speedsensorless induction motor drive using artificial intelligence is also known [Vas].
Up to now the studied literature by the author, only the research of Monmasson and his group is reported as direct application of reconfigurable structures in vector control for AC Drives [Monmasson, Tazi]. The most significant result introduced in reconfigurable control was the parallelmachine control architecture.
Current
Controller
Controller
+
Flux
Model
Speed
Controller
Vector control structure for AC drive
[is]
Current
feedback
Set parameters
Power
imR
Converter
Magnetising
Flux
PWM
+
S
motor

Reference
speed
+
S
Speed
feedback

w
Source Texas Instruments
Most of the motor control applications use asynchronous motors.
The most often used method to control induction motors is the field oriented control method to achieve the best dynamic behaviour.
Using the Park’s direct and reverse transformations the AC drive can be controlled like a separately exited DC machine, whereby the direct (d) path is representing the flux building component and the quadrate (q) path sets the electrical torque.
Best results are obtained when the magnetising current imR is kept constant, which is direct proportional to the rotor flux r under the assumption that the main inductance Lh is constant
(2)
(3)  (4)
Based on the mathematical model of the induction machine in field coordinates, given in equation (14), a controller was developed and a flux model was derived.
Transformation
System
Transformations
TwoLevel Current Tracking Controller
Flux Controller
i*sd
i*sq
*r
TA
[D(r)]
[is]*
i*sdr
i*sdr
TS
[A]1

VSI



[(r)]
Position Controller
Speed Controller
cosr
sinr
Current
Sensors
[is]*
isd
TS
[A]
imrd
imrq
r
imr
Lm
AF
C1Imr
r
isq
Induction
machine
Orientationfield
Computation
Integrator
zp
r
Control Strategy
Field Oriented DC Quantities
Two Phase AC Quantities
ThreePhase
AC Quantities
Vector control system for voltagesource inverterfed induction machine
Starting from the mentioned modularity a reconfigurable controller structure it is introduced.
Triscend’s CSoC:
Xilinx’s FPGA Virtex:
Q and P represent the two control structures, C and C’ represent the reconfiguration control, [is] and [is]* are the observed current signal and the current control signal, respectively.