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

A New Low-Cost SHRM for

Adjustable-Speed Pump

Applications

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

A New Low-Cost SHRM for Adjustable-Speed Pump Applications

index

Adjustable speed pump


introduction

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

Adjustable speed drives (ASDs)

provide an efficient flow control

alternative by varying a pump’s

rotational speed.

“An electric motor that induces non-permanent

magnetic poles on the ferromagnetic motor.

Torque is generated through the phenomenon of

magnetic reluctance .”


RELUCTANCE MOTOR

Synchronous

reluctance motor

Variable /switched

reluctance motor

Variable reluctance

stepping motor

TYPES OF RELUCTANCE MOTOR


1

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


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,


1

SPECIFICATIONS DIMENSIONS

RATED POWER 30 W

RATED SPEED 3000 rpm

OUTER DIAMETER 80 mm

STACK LENGTH 25 mm

RECTANGULAR

FERRATE

PERMANENT MAGNET

(H X W X L)

4mm x 18mm

x40mm

REMANENCE OF

MAGNETS

0.39 T

COERCIVITY OF

MAGNETS

250 KA/m

THE PROPOSED SINGLE PHASE HSR MOTOR


1

Four S poles and two PM-poles.

Rotor pole has a small slots close to

its surface ( stepped rotor pole ). .

MAJOR PARTS OF PROPOSED SINGLE PHASE HSRM

STATOR ROTOR

Self-starting capability.

Anticlockwise rotation


1

WORKING OF PROPOSED SINGLE PHASE SHRM

I II III

Rotor position ; Non-slotted parts of

the rotor poles are aligned with the

PM-poles.

A demagnetization current is

provided

.

The rotor will be aligned with the

reluctance poles

• Positive reluctance torque & PM

interaction torque

• Cogging torque is negative.

• The current is made zero

A positive cogging torque will then

continue to pull the rotor poles to the

position aligned with the PM-poles.

The motor is designed to rotate in

the anticlockwise direction.


1

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


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.


1

PRINCIPLE OF FLUX CONCENTRATION CONFIGURATION

Cheap ferrite magnets can produce.

High air gap flux density

High positive cogging torque.

More flexibility in shaping the

cogging torque characteristic


1

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.


1

Static test bench

Back EMF,

Flux-linkage profiles

Cogging torque

Interaction torque

STATIC MEASUREMENT RESULTS


1

COMPARISON OF THE MEASURED AND CALCULATED

BACK EMF WAVEFORMS AT A SPEED OF 48 (RPM).


1


FLUX LINKAGE PROFILES AT THE MIN. &MAX.INDUCTANCE.

.


1


COGGING TORQUE WAVEFORMS


1


INTERACTION TORQUE


1

Taver4 X Area of BCDE

2π=

Taver2

π= Ia (L max - Lmin)

2][ + Ia.∆∂pm

2

Flux linkage v/s current

• Taver

Average interaction torque

• 4 Number of rotor poles

• Ia DC phase current.

• L Linear inductance

• ∆∂ PM flux-linkage from minimum inductance

position to maximum inductance position.

AVERAGE INTERACTION TORQUE


1

PARAMETERS MEASURED CALCULATED

MAX.INDUCTANCE 97.5 120.8

MIN.INDUCTANCE 52.0 57.5

CHANGE OF PM FLUX

LINKAGE L MIN-LMAX

(M.WB.TURNS) 29.0 41.3

MEASURED AND CALCULATED MAX. AND MIN.

INDUCTANCES & CHANGE OF THE PM FLUX LINKAGES

Errors in the measurement may be affected

due to

Wrong air gap lengths under both poles

Measurement accuracy affected by the

frictional torque.

Misalignment

• Shafts of the torque transducer .

• The coupling.

• Test motor.


1

AVERAGE TORQUE VS. AMPLITUDE OF SQUARE CURRENT

WAVEFORM WITH CONSTANT AMPLITUDE

winding current has to be increased by 30%

copper loss would be 70% extra

Measured average torque is about 30%

lower than the expected value.

Due to the reduction in the Lmin & Lmax, and ∆∂

To achieve the rated torque


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

STEADY-STATE MEASUREMENT RESULTS


1

MEASURED VOLTAGE AND CURRENT WAVEFORMS

AT 2500 RPM, FREE-SHAFT


1

MEASURED MOTOR VOLTAGE AT SPEED 2600 (RPM)


1

MEASURED MOTOR CURRENT AT SPEED 2600 (RPM)


1

MEASURED MOTOR INSTANTANEOUS TORQUE AT SPEED

2600 (RPM)


Non-magnetic and no-conductive can

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.

INFERENCE OF STEADY-STATE MEASUREMENT

RESULTS

A New Low-Cost SHRM for Adjustable-Speed Pump

Applications A New Low-Cost SHRM for Adjustable-Speed Pump Applications

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.

CONCLUSION


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,


REFERENCES

[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


Applications


Applications

Thank

you!

ANY

QUESTION

S?


Applications

Engineering

A new low cost shrm for adjustable-speed pump applications