AUXILIARY POWER CONTROL OF
HYBRID ELECTRIC VEHICLES
DYNAMIC MODELS OF THE AUXILIARY
POWER UNIT (APU) COMPONENT
APU POWER CONTROL
What is Hybrid Electric Vehicle?
Need for A.P.U.
Role of Supervisor
The objective to be satisfied are
(1) To fast activate the A.P.U.
(2) To limit the current overshoots and
(3) To maintain constant shaft speed
Different A.P.U. Operating Phases
Role of reference governor
DYNAMIC MODELS OF THE
AUXILIARY POWER UNIT
Internal Combustion Engine
Three Phase Induction Motor
Power Converter will be considered to be
(1) Stator Current iD and iQ
(2) Rotor flux ΦD and ΦQ
DYNAMIC MODEL OF THE
Rotating reference frame synchronous with rotor
Obtain the model by using mass balance and
ideal gas equations
Obtain torque expression from in-cylinder
The intake manifold is modeled
ENGINE OPERATING CYCLES
IC Engine torque
Sum of torque determines the shaft
Main objective of APU
Different operating phases
(1) start up phase
(2) warm-up phase
(3) Power generation phases
(a) Low-power phase
(b) high-power phase
(4) Shut down phase
Fig. 1. APU operating phase and state transitions
APU POWER CONTROL
Phases Control Schemes
Torque Control of the EM
Internal combustion Engine control
PHASE CONTROL SCHEMES
Different controller for different operating
Fig. 2. APU general control scheme
Fig. 3. APU control scheme during start-up, shut-down and warm-up phases
Fig. 4. APU control scheme during the low-power and high-power
TORQUE CONTROL OF THE EM
Fig. 5. Block scheme of torque controller for EM
Finally we get,
Fig. 6. Cascade current and flux control scheme
Operates during low-power and high
Structure depends on the specific power
(1) low-power phase
(2) high-power phase
(a) Reference speed is constant
(b) reference torque for the EM
(c) Problems in the management of the
APU by oscillation
(d) The reference torque can be
(2) High-power phase
(a) Torque and power at 80% of their
(b) Demanded value of power
(c) The reference torque
INTERNAL COMBUSTION ENGINE
Enabled during power generation phases
The model used by the observer is
The condition obtained is
Different operating phases have corresponding
controller for ICE and EM
A reference governor have been designed
Reference governor exploits the separation
between slow dynamics and fast dynamics
The proposed APU controller yields good steady
state and dynamic performance
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