Robust and Efficient Control of an Induction Machine for an Electric Vehicle

1
Robust and Efficient Control of an Induction
Machine for an Electric Vehicle

• Arbin Ebrahim and Dr. Gregory MurphyUniversity
  of Alabama

2
Outline

• Project Objectives
• What is Adaptive Control?
• Definition of Adaptive Backstepping
• Advantages of Using a Adaptive Backstepping
  Controller
• Problem Formulation
• Design Procedures
• Project Work Summary

3
Project Objectives

• Robust and efficient control of an induction
  motor for an electric vehicle
• Track the speed of an induction motor to a
  desired reference trajectory under time-varying
  load torque for an electric vehicle
• Robust control of an electric vehicle induction
  motor under varying changes in the motor
  parameters.

4
What is an Adaptive Controller?
Learning Mechanisms (Parameter Adaptation)
Coordination Mechanisms
Robust Feedback
x
u
Plant
Adjustable Model Compensation
r (t)
y

• To invent, design and build systems capable of
  controlling unknown plants or
• adapting to unpredictable changes in the
  environment

5
What is Backstepping?
x
u
d
?
?
f (x)
0
,
z
u
x
?
?
-
0
,
f ' (x)
V,Va Lyapunov Functions
x, State Variables
z Virtual State
(x) Virtual Control
u plant input

• Backstepping is to design a controller for a
  system recursively by considering some of the
  state variables as Virtual Controls and
  designing for them intermediate control laws

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Advantages of Adaptive Backstepping Controller
Design Procedure

• Both the stability properties and control law can
  be ensured in this same step
• The Control Law can be obtained in steps no
  greater than the order of the system
• In adaptive backstepping unknown plant parameters
  can be easily dealt with to design control laws
• Observers can be easily incorporated in the
  design procedure to perform observer backstepping

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Problem Formulation
Flux Command
-

Flux Controller
Rotating Stator Frame to Stationary Stator
Frame Conversion
Space Vector Modulation
Power Stage
Speed Controller

-
Speed
Command
Flux Estimator
Where
Time varying Load Torque
Flux component of the Stator Current
IM
Speed component of the Stator Current
,
Voltages in the rotating stator frame
Measured Speed of the Motor
Estimated Flux of the motor
,
,
Measured Stator Currents
,
,
Applied three phase stator voltages
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Design Procedure

• Modeling-
• The equations representing the dynamics of
  motion of the Induction Motor is derived in the
  three phase, stationary and rotating stator frame
  co-ordinates and analyzed for the application of
  Adaptive Backstepping procedure.
• Controller Design-
• Flux Controller-
• An Observer Backstepping Flux Controller is
  designed using flux observers to make the
  estimated flux track a desired reference
  trajectory to ensure that sufficient torque is
  delivered to Load
• Speed Controller-
• An Adaptive Backstepping Speed Controller
  is designed to make the measured speed of the
  motor track a desired reference trajectory under
  varying Load Torque Conditions
• Simulation-
• The adaptive controllers designed are
  simulated in the Simulink environment to verify
  the results

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Design ProcedureContinued

• Hardware Implementation-
• The Adaptive Controllers developed are
  verified in real time using an Induction Motor
  tied to a varying load. The results are observed
  and conclusions made

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Project Work Summary

• Model the Induction Motor in the stationary and
  rotating stator frames so that Vector Control can
  be applied to develop a speed controller as well
  as a flux contoller
• Apply adaptive backstepping procedure to develop
  a speed controller for the motor speed to track a
  desired reference speed under time varying load
  conditions
• Design flux observers to estimate the flux and
  design an observer based backstepping controller
  for the flux to track a desired reference
  trajectory so that sufficient torque can be
  supplied to the Load
• Develop a modular design in Simulink environment
  for the motor models, observer models, controller
  models, and etc for simulation
• Implement real-time controller application to an
  Induction Motor for verifying and comparing the
  simulation results to the real-time results to
  make conclusions and recommendations on future
  research