This document presents a new low-cost switched reluctance motor (SHRM) for adjustable-speed pump applications. The motor uses inexpensive ferrite magnets arranged in a flux concentration configuration to increase torque density compared to conventional single-phase SR motors. Static and steady-state test results show that the prototype motor can produce the rated torque of 30W at 3000 rpm, though the measured torque is about 30% lower than expected, likely due to measurement errors. The efficiency of the overall drive system at rated speed is 70%, with major losses from iron loss in the motor can estimated at around 20W. Future work on noise reduction would be needed for indoor pump applications.

1. A New Low-Cost SHRM for
Adjustable-Speed Pump
Applications
PRESENTED BY
SWATHI VENUGOPAL
SEMESTER 7, ROLL NO
60
EEE ,GOVT.RIT
GUIDED BY
PROF.SREELEAKHA
EEE ,GOVT.RIT

2. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
index
1 INTRODUCTION 12
1 INTRODUCTION 12
2 PROPOSED HSRM 13
3 STATIC MEASUREMENT 14
4 STEDY STATE
MEASUREMENT
15
5 CONCLUSION 16
6 REFERENCE 17

3. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
introduction
Adjustable speed pump
 pumps are selected
 maximum system demand, + potential future demands.
 oversized,
 multiple operating points
 Control of flow
 Throttling valves
 control flow by increasing the system’s
backpressure or resistance
 Loss in efficiency

4. Adjustable speed drives (ASDs)
provide an efficient flow control
alternative by varying a pump’s
rotational speed.

5. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
RELUCTANCE MOTOR
“An electric motor that induces non-permanent
magnetic poles on the ferromagnetic motor.
Torque is generated through the phenomenon of
magnetic reluctance .”

6. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
TYPES OF RELUCTANCE MOTOR
Synchronous
reluctance motor
Variable /switched
reluctance motor
Variable reluctance
stepping motor

7. 1
A New Low-Cost SHRM for Adjustable-Speed Pump Applications
SWITCHED RELUCTANCE MOTOR
“The movement of the rotor,production of torque and
power, involves a switching of currents into stator
windings when there is a variation of reluctance
- SWITCHED RELUCTANCE
MOTOR (SRM).”
OPERATION

8. SINGLE PHASE SWITCHED RELUCTANCE MOTOR
 When the stator and rotor poles are aligned
 Current is turned off
 Rotor keeps moving due to the stored KE
As the poles become unaligned
 Stator winding again is energized,
 producing an electromagnetic torque.
 Problem with 1φ SRM
 Alignment at standstill torque produced may be lower
than the load torque at starting.
 permanent magnet on the stator to pull the rotor away
from the alignment,

A New Low-Cost SHRM for Adjustable-Speed Pump Applications

9. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
THE PROPOSED SINGLE PHASE HSR MOTOR
1
SPECIFICATIONS DIMENSIONS
RATED POWER 30 W
RATED SPEED 3000 rpm
OUTER DIAMETER 80 mm
STACK LENGTH 25 mm
RECTANGULAR
FERRATE
4mm x 18mm
PERMANENT MAGNET
x40mm
(H X W X L)
REMANENCE OF
MAGNETS
0.39 T
COERCIVITY OF
MAGNETS
250 KA/m

10. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
MAJOR PARTS OF PROPOSED SINGLE PHASE HSRM
1
 Four S poles and two PM-poles.
 Rotor pole has a small slots close to
its surface ( stepped rotor pole ).
.
 Self-starting capability.
 Anticlockwise rotation
STATOR ROTOR

11. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
  Rotor The motor position is designed ; Non-slotted to rotate parts in
of
 A positive cogging torque will then
the anticlockwise direction.
continue to pull the rotor poles to the
position aligned with the PM-poles.
1
WORKING OF PROPOSED SINGLE PHASE SHRM
 The rotor will be aligned with the
reluctance poles
the rotor poles are aligned with the
PM-poles.
• Positive reluctance torque & PM
 A demagnetization current is
interaction torque
provided
.
• Cogging torque is negative.
• The current is made zero
I II III

12. 1
A New Low-Cost SHRM for Adjustable-Speed Pump Applications
 GRAPH OBTAINED FROM 2D FEM
 The rotor will settle at a position near point A
before starting.
 Positive torque will appear if the winding current
is increased (self starting)
 Steady state operations -Current flowing B and
C.
 After the rotor has passed position C,
 Current should be zero
 Cogging torque -positive motoring torque

13. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
 DEMONSTRATION OF HOW THE PM FLUX LINKAGE
COULD BE USED TO INCREASE THE TOTAL TORQUE
 Area enclosed by curve 1,2 & AB ;
Average torque for a DC current
 Curve 3-the total enclosed area for the same
current will be increased
 The PM flux move the flux-linkage curve so as to
increase the motor’s torque density
 Due to PM interaction torque component.

14. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
 PRINCIPLE OF FLUX CONCENTRATION CONFIGURATION
1
 Cheap ferrite magnets can produce.
 High air gap flux density
 High positive cogging torque.
 More flexibility in shaping the
cogging torque characteristic

15. 1
A New Low-Cost SHRM for Adjustable-Speed Pump Applications
 COGGING TORQUE V/S PM-POLE ARCS.
 Reducing the PM-pole arc by 20%, the
peak cogging torque value could be
increased by about 35%.
 Cogging torque
 No contribution to the average torque.
 Negative where the reluctance & PM interaction
torque are positive.
 Move part of the positive torque by the winding
current to the region where the current is zero.
 The ideal cogging torque
 waveform should be trapezoidal
 Average positive cogging torque = rated torque.

16. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
 Static test bench
 Back EMF,
 Flux-linkage profiles
 Cogging torque
 Interaction torque
1
STATIC MEASUREMENT RESULTS

17.  COMPARISON OF THE MEASURED AND CALCULATED
BACK EMF WAVEFORMS AT A SPEED OF 48 (RPM).
1
A New Low-Cost SHRM for Adjustable-Speed Pump Applications

18. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
 COMPARISON OF THE MEASURED AND CALCULATED
FLUX LINKAGE PROFILES AT THE MIN. &MAX.INDUCTANCE.
1
.

19. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
 COMPARISON OF THE MEASURED AND CALCULATED
1
COGGING TORQUE WAVEFORMS

20. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
 COMPARISON OF THE MEASURED AND CALCULATED
1
INTERACTION TORQUE

21. 1
A New Low-Cost SHRM for Adjustable-Speed Pump Applications
Taver
 AVERAGE INTERACTION TORQUE
4 X Area of BCDE
2π
=
Taver
2
π
[ + Ia.Δ∂pm ]
= Ia (L max - Lmin)
2
2
Flux linkage v/s current
• T
aver Average interaction torque
• 4 Number of rotor poles
• Ia DC phase current.
• L Linear inductance
• Δ∂ PM flux-linkage from minimum inductance
position to maximum inductance position.

22. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
INDUCTANCES & CHANGE OF THE PM FLUX LINKAGES
1
 MEASURED AND CALCULATED MAX. AND MIN.
 PARAMETERS Errors in the measurement MEASURED may CALCULATED
be affected
due to
 Wrong air gap lengths under both poles
 Measurement accuracy affected by the
MAX.INDUCTANCE 97.5 120.8
frictional torque.
MIN.INDUCTANCE 52.0 57.5
 Misalignment
• Shafts of the torque transducer .
• The coupling.
• Test motor.
CHANGE OF PM FLUX
LINKAGE L MIN-LMAX
(M.WB.TURNS) 29.0 41.3

23. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
 AVERAGE TORQUE VS. AMPLITUDE OF SQUARE CURRENT
1
WAVEFORM WITH CONSTANT AMPLITUDE
 Measured average torque is about 30%
lower than the expected value.
 Due to the reduction in the Lmin & Lmax, and Δ∂
 To achieve the rated torque
 winding current has to be increased by 30%
 copper loss would be 70% extra

24. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
STEADY-STATE MEASUREMENT RESULTS
1
 Equipment used for steady-state performance
measurements
COMPONENTS SPECIFICATIONS
MOTOR CONTROLLER ASYMMETRICAL HALF-BRIDGE
CONVERTER
TORQUE TRANSDUCER OPTICAL ROTARY TORQUE
TRANSDUCER(FULL SCALE
TORQUE 1 NM)
LOAD ZF HYSTERESIS BRAKE
DATA ACQUISITION BRUEL & KAJAER PULSE

25. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
 MEASURED VOLTAGE AND CURRENT WAVEFORMS
1
AT 2500 RPM, FREE-SHAFT

26.  MEASURED MOTOR VOLTAGE AT SPEED 2600 (RPM)
1
A New Low-Cost SHRM for Adjustable-Speed Pump Applications

27. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
 MEASURED MOTOR CURRENT AT SPEED 2600 (RPM)
1


28. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
 MEASURED MOTOR INSTANTANEOUS TORQUE AT SPEED
1
2600 (RPM)

29. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
A New Low-Cost SHRM for Adjustable-Speed Pump
Applications
 INFERENCE OF STEADY-STATE MEASUREMENT
RESULTS
 Instantaneous torque produced by the motor
is affected by the friction and mechanical
oscillation.
 Whole drive system’s efficiency at the rated
speed is 70%.
 Major loss is Iron loss in the can, extremely
high and was estimated .(≈20 watts).
 For indoor pumps, future work on noise
analysis and reduction will be required.
 Non-magnetic and no-conductive can

30. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
CONCLUSION
 This motor has higher torque density than
conventional single-phase SR motors by properly
using PM flux.
 It uses cheap ferrite magnets arranged in a flux
concentration manner.
 The rotor has a special design for reducing the
hydraulic loss associated with wet-running.

31. A New Low-Cost SHRM for Adjustable-Speed Pump Applications
REFERENCES
[1] R. Krishnan, S. Lee, ‘PM brushless DC motor drive with a new
power-converter topology’, IEEE Transactions on Industry
[2] R. Krishnan, ‘A novel single-switch-per-phase converter
topology for four-quadrant PM brushless DC motor drive’, IEEE
Transactions on
Industry
[3] Rolf Muller, ‘Collector-less DC motor’, US Patent,
[4] C. Koechli, Y. Perriard, M. Jufer, ‘One phase brushless DC
motor
analysis’, Proceeding of International Conference on Electrical
Machines, 1998, Pages: 639-644
5] Alex Horng, ‘Non-brush DC motor with an improved stator’, US
Patent,
[6] Alex Horng, ‘Non-brush DC motor with new improved stator’,
US
Patent,
[7] Johan C. Compter, ‘Single-phase reluctance motor’, US Patent,

32. REFERENCES
A New Low-Cost SHRM for Adjustable-Speed Pump
Applications
[8] Gary E. Horst, ‘Hybrid single-phase variable reluctance
motor’, US Patent,
[9] Gary E. Horst, ‘Shifted pole single phase variable reluctance
motor’, US Patent, No. 5,294,856, Mar. 1994
[10] Peter Lurkens, ‘Single-phase reluctance motor adapted to
start in a desired direction of rotation’, US Patent,
[11] T. Higuchi,; J.O. Fiedler, R.W. De Doncker, ‘On the design of
a single-phase switched reluctance motor’,
[12] John M. Stephenson , ‘Switched reluctance motors’, US
Patent,
[13] V. Torok, K. Loreth, ‘The world's simplest motor for variable
speed
control

33. A New Low-Cost SHRM for Adjustable-Speed Pump
Applications
Thank
you!

34. A New Low-Cost SHRM for Adjustable-Speed Pump
Applications
ANY
QUESTION
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