A 3'4 kW, 42 V HIGH EFFICIENCY AUTOMOTIVE POWER GENERATION SYSTEM

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A 3.4 kW, 42 V HIGH EFFICIENCY AUTOMOTIVE POWER
GENERATION SYSTEM
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BACKGROUND
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NEW POWER GENERATION SYSTEMS
42V System
14V System
High power capability (100/250A twice the CS144)


High efficiency (76 idle/66 cruising - 30
improvement)


Efficiency improvement over 14 V system

Low inertia (2/3 present) due to hallow rotor

• Low cost controller

Manufacturing flexibility (1-4 kW)

Quiet operation (8db less noise than CS 144)




? System cost is an issue
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PM MACHINE
Dimensions
Outside diameter D
130.0 mm
o
Overall length L 138.4 mm
Constructional Features
Stator


3-phase winding

Large gap 0.7 mm
Rotor


Four MQ3 ring magnets assembled without
magnetizing
One piece hollow core


Magnetized after rotor assembly
PM rotor
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VARIABLE FREQUENCY SCR BRIDGE CONTROLLER
Simplified Block Diagram
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PHASE-LOCK-LOOP (PLL) CIRCUITS
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PM ALTERNATOR
CONTROLLER
Figure. 3. Prototype SCR bridge controller and
the PM alternator
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Figure. 5. Components of the PM machine with
stator , rotor and end plates.
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(No Transcript)
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FULL LOAD EFFICIENCIES AT 42.5 V
TEST RESULTS
(42V SYSTEM )
FULL LOAD CONDITION

IDLE SPEED_at_ 2150 RPM
84.5 efficiency at 46A load

CRUISING SPEED _at_ 6500 RPM


70.7 efficiency _at_ 80A load
(
vs
64 for 14V PERMAGEN at 210A)
PART LOAD EFFICIENCIES AT 42.5 V
PART LOAD CONDITION
IDLE SPEED_at_ 2150 RPM



77 efficiency _at_ 7A load


CRUISING SPEED _at_ 6500 RPM


44.5 efficiency _at_ 7A load
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Figure. 14a. Comparison between 14 V and 42 V
high power PM generators and the Lundell.

• 42 V PM alternator system is more efficient than
  Lundell type CS 144
• and 14 V PM alternator system (Permagen)
• - At idle speed 5 over the 14 V Permagen and
  30 over the CS 144
• - At cruising speed 6.7 over the 14 V Permagen
  and 13 over CS 144

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Figure. 14b. Comparison between 14 V and 42 V
high power PM generators and the Lundell.
? PM alternator systems deliver more power than
Lundell type machine
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LOAD DUMP TEST
Figure 15. Schematic diagram of the circuit for
load dump test.
Figure 16. Measured load dump voltage at 75 a
output current at the alternator
speed of 6500 r/min without load dump voltage
limiting circuit..
? The load dump voltage is controlled to the
acceptable limit of 57 V
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Figure. 17. The circuit diagram for the limiting
load dump voltage.
Figure. 18. Measured load dump voltage at the
alternator speed of 6500 r/min with 80 A
output current with load dump voltage
limiting circuit.
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CONCLUSIONS
1. A 42 V, 3.3 kW PM alternator with a SCR bridge
controller has been built and tested
successfully. 2. The system improves efficiency
over the 14 V Lundell machine (CS144) and
14 V PM alternator with dual SCR bridge (up to
the cruising speed) - At idle speed 30 over
the CS 144 (Lundell machine) and
5 over 14 V PM alternator - At
cruising speed 13 over CS 144 and 6.7 over PM
alternator 3. Single SCR bridge is used to
reduce the system cost 4. The designed load dump
voltage controller limits the load dump voltage
to the acceptable limit of 57 V