Prof. J

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FORCED DYNAMICS CONTROL OF INDUCTION MOTOR WITH
SELECTABLE DYNAMICS

• Prof. Ján VITTEK Dr. Juraj ALTUS
• University of Žilina, SK
• Department of Electric Traction and Energetics
• Prof. Stephen J. DODDS Dr. Roy Perryman
• University of East London, UK
• School of Electrical and Manufacturing Engineering

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FORCED DYNAMICS SPEED CONTROL of EL. DRIVES with
Induction Motors

• Application of
• block control principle
• linearising function
• pseudo-sliding mode observers for angular speed
  estimation
• filtering observer including load torque
  estimation
• Achievements
• speed control without shaft sensor
• closed-loop dynamics for speed control chosen to
  suit particular drive application
• enhanced reliability of whole electric drive

Research CO-ORDINATION Prof. Stephen J.
DODDS University of East London School of
Electrical and Manufacturing Engineering Departmen
t of Electrical Electronic Engineering Longbridg
e Road DAGENHAM, RM8 2AS United Kingdom
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BASIC PRINCIPLE
y
nonlinear plant
LINEARISING FUNCTION
u
specified
u
y
nonlinear control law
nonlinear plant
closed-loop system
y
i.e.,
linear and de-coupled closed-loop system with
prescribed dynamics
MOTION SEPARATION
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MODEL OF MOTOR AND LOAD
expressed in stator-fixed frame
motor torque
rotor magnetic flux linkage
rotor speed
stator currents
stator voltages
stator and rotor resistances
stator, rotor and mutual inductances
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CONTROL LAW DESIGN
SIMPLIFICATION OF CONTROL PROBLEM BY
INNER/OUTER CONTROL LOOP STRUCTURE
r
Y
Rotor speed and rotor magnetic flux norm are
demanded values
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MASTER CONTROL LAWindependently controls rotor
speed and magnetic flux norm with first order
dynamics and time constants, T1 and T2
linearising functions
master control law
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Acceleration Demands for Three Various Dynamics
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SET OF OBSRVERS FOR STATE ESTIMATION AND FILTERING
1.Rotor Flux Estimator
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Pseudo-Sliding Mode Observer andAngular Velocity
Extractor
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3. Filtering Observer
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Overall Control Systems Structure
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Comparison of Control System Response and
Demanded Response
The actual system response is compared with the
simulated output of the ideal speed response of
prescribed dynamics .
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Experimental Results for Induction Motor
DriveDriven by First Order Dynamics
Experimental Bench of East London University,
Results Daniel Vysoudil, AD Developments,
Milton Keynes, UK
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Experimental Results for Constant Acceleration
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Experimental Results for First Order Dynamics
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Experimental Results for Second Order Dynamics
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Second Order Dynamics and Various Damping Factor
c)
b)
a)
critically dumped system x1
underdumped system x0.5
overdumped system x1.5
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Various Prescribed Dynamicsincluding MRAC
a) constant torque
b) first order dyn.
c) second ord. dyn.
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Conclusions and Recommendations

• A new approach to the control of electric drives
  with induction motors, based on feedback
  linearisation has been developed and
  experimentally proven.
• Three various prescribed dynamics to speed
  demands were achieved.
• Further research will focus on the application of
  the new approach to
• a) high power electric drives, including
  magnetic saturation and high speed applications,
  and
• b) enhancement of control system for outer loop
  based on MRAC or SMC to improve precision of
  control.