The design method of motor insulation system for eco ...20design... · 2.3 Equivalent insulation resistance ... (coil to stator core) Contact area A tooth of a stator core Coil Slot

EVS28 KINTEX, Korea, May 3-6, 2015

The design method of motor insulation

system for eco-friendly vehicles

Yong Ho Kim1, Jong Bin Park2, Sang Han Lee3, Hyeong Geun Park, Seung Yong Park

1Electric Power Engineering Team, Hyundai MOBIS, Korea

Hyeoun Dong Lee (corresponding author), [email protected] 2Eco Engineering Group, Hyundai MOBIS, Korea

3 Electric Power Engineering Design Team, Hyundai Motor Group, Korea

mailto:[email protected]

Outline

Ⅰ. Introduction 1. Importance of insulation systems

2. Test principle of insulation systems

Ⅱ. Study on insulation systems 1. High potential test for insulation systems

2. Method of Insulation equivalent circuit

2.1 Equivalent circuit

2.2 Voltage equation

2.3 Equivalent insulation resistance

2.4 Prediction on insulation systems performance

Ⅲ. Summary

2

◆ Introduction

1. Importance of insulation systems

- Protecting insulation systems from external factors.

: surge, high voltage, vibration shocks

: ambient, thermal stress

- Preventing the insulation breakdown.

: circuit short between phase and phase, turn and turn & phase to ground

3

Insulation paper Enameled wires Impregnation

Insulation System Mechanical

Stress Electrical

Stress

Thermal

Stress Ambient

Stress

◆ Introduction

2. Test principle of insulation systems

: Purpose of insulation testing is to identify windings

with high risk factors of failure.

4

Test method Advantage Disadvantage Remark

Insulation

Resistance

- Low cost

- Easy perform

- Insensitive to internal problems

in the insulation (voids) DC

Surge - Confirm the insulation of coil

(scratch, pinhole)

- Applying a impulse voltage

higher than the operating voltage

for a short time

Impulse

High Potential - Sensitive to internal insulation

problems - High cost AC

Study

◆ Study on insulation systems

5

A high potential test

1. High potential test for insulation systems

A state of insulation systems is identified

by a high potential test.

A high potential test is to check a leakage current

that flows from a coil to a housing.

Test method and diagnostic methods.

- A test voltage is applied to a coil of a motor for 60 sec.

- The leakage current is identified as a state

of insulation systems.

Checking the measured leakage current compared

with a reference value.

Test method Voltage

(Vrms)

Duration

(sec.)

Frequency

(Hz)

High Potential 1000+V×2 60 50 or 60


6

Voltage equation

(Applied to an insulation resistance)

Estimating the resistivity coefficient

Prediction a high potential test

A method of Insulation equivalent circuit

Calculation an insulation resistance

Insulation equivalent circuit

2. Method of Insulation equivalent circuit

A diagnostic method of a high potential

test is to measure a leakage current that

flows from a coil to a housing.

To study a leakage current, a method

of an insulation equivalent circuit is applied.

A voltage equation using an insulation resistance

is applied as the governing equation.

After analyzing the resistivity coefficient of

an insulation resistance, a voltage equation is

calculated.

The result of a high potential test is compared

with a estimating leakage current.


7

Stator

Core

Coil

Current Housing

Leakage

Current, IL


Voltage equation







High Potential Test

A leakage current flows from a coil to a housing

for applying a voltage.


8


V

Stator

Core

Housing

Enamel + Paper + Resin

Insulation

Systems

IL

C R

IC IR

IL

V


A leakage current passes through the insulation resistance.

Insulation systems consist of enamel coil, insulation paper, impregnating resin.

Voltage equation







Loss Current, IR

Capacitor Current, IC

Leakage Current, IL


9


Insulation & phase resistances of motor are

shown as a insulation circuit.

Voltage equation







Resistance of motor

A, B, C phase resistance, Ra, Rb, Rc

A, B, C insulation resistance, Ria, Rib, Ric

10


In a resistance equation of motor, a insulation

resistance is much larger than a phase resistance.

Voltage equation








◇ Equivalent circuit & Voltage equation

11


Enamel + Paper + Resin

Insulation

Systems

Voltage equation

A voltage equation is shown by a leakage current

and a insulation resistance.

Voltage equation







R insulation = R coil + R paper + R resin

V = Ileakage× R insulation


2.3 Estimating the resistivity coefficient

12


Voltage equation







1

insulation

insulation

AC

d R

dR

A

A: contact area/stack length

(coil to stator core)

Contact area

A tooth of

a stator core

Coil

Slot of stator core

Stator

core

coil

d: Distance between a coil

and a stator core

A: contact area

d: distance

ε: permittivity

ρ: resistivity coefficient

2.3 Estimating the resistivity coefficient

13


Voltage equation







Item

Condition Test

Result

A

(mm2)

Insulation paper enamel thickness Leakage

current

d

(mm) ρ

d

(mm) ρ -

Model1

of test1 2,105 0.5 - 0.038 - 1

Model1

of test2 2,105 0.6 - 0.038 - 0.88

A resistivity coefficient of a insulation paper is

calculated by a voltage equation.

1 1 sin/ enamel coil paper reV I R R R

2 2 sin/ enamel coil paper reV I R R R

2 1

2 1

1 2

2 1

2 1 1 2

1 1( )

1 1( ) ( )

1 1( )( )

p p

paper

R R VI I

d dV

A I I

AV

I I d d

2.4 Calculation an insulation resistance

14


Voltage equation







Item

Condition Test

Result

A

(mm2)

Insulation paper enamel thickness Leakage

current

d

(mm) ρ

d

(mm) ρ -

Model1

of test1 2,105 0.5 - 0.038 - 1

Model1

of test2 2,105 0.6 - 0.038 - 0.88

Insulation resistances of a enamel coil and a

insulation paper are calculated by a voltage equation.

1 1 sin/ ( )enamel coil paper reR V I R R

sin ,re enamel coil paperR R Rpaper

dR

A

2.5 Prediction a high potential test

15


Voltage equation







A comparison of the predicted and test data

results have 3.3 to 11.1% variation.

◆ A comparison of the predicted and test result

Item Leakage current (%)

Test result Prediction

Model1 100 103.3 (3.3%↑)

Model2 100 88.9 (11.1%↓)

Model3 100 95.9 (4.1%↓)

Model1 Model2 Model3

◆ Summary

I. A insulation resistance and a equivalent circuit applied the voltage equation is

developed for a Prediction on insulation systems performance of a motor.

II. Using the voltage equation and the test result the resistivity coefficients of

insulation systems are estimated. The insulation systems performance of Other

motors is predicted.

III. Although a comparison of the predicted and test data results have 3.3 to 11.1%

variation, the difference will be reduced through gathering data and studying a

insulation resistance and a equivalent circuit applied the voltage equation.

16

Documents

The design method of motor insulation system for eco ...20design... · 2.3 Equivalent insulation resistance ... (coil to stator core) Contact area A tooth of a stator core Coil Slot