Load Dump Analysis

Ansoft CorporationPittsburgh, PA

2-3 kW power generation capability

Engine

12VBattery

Loads

14V

Starter

OPENs occur here….

…or here.

WHY?• Cables corrode and

break• Nuts & bolts come

loose• Mechanics disconnect

the wrong wire at the wrong time.

14 V Single Battery System

Alternator

…or here…

InstancesA major OEM received six new

42 volt alternators from a supplier. Three were destroyed in testing during the first month. That’s $15,000 up in smoke. They bought SIMPLORER.

Another major OEM worked for over a year to create an accurate Saber alternator model that could be fit to parametric data. They have not succeeded. Ansoft and the OEM are discussing the deployment of SIMPLORER.

Why should you be interested?Solving “by hand”

Time consumingError prone

TestingDestroy or degrade partsVery difficult to repeatInsufficient quantity of parts available

SimulationParts are virtual…don’t “smoke”Exactly repeatable

All are necessary to some extent and support one another.

Options are few!

Ansoft’s Solution

RMxprtMotor/generator design tool that can automatically produce a model for SIMPLORER

SIMPLORERsimulate the alternator, the battery, the loads and the devices and strategies that control and regulate the alternator

Design Flow

Maxwell2DMaxwell3D

Static, Harmonic, Transient

Maxwell Equivalent Circuit Generator

Geometry & Material

Parametric Solution

Parameter Sets, Lookup

Tables, Models

Model G

eneration

Model Generation

Model Order Reduction

Mod

el

Gen

erat

ion

Parameters &

Models

Optimization

Optimization

Optimization

RMxprt

Multi Domain SimulationSIMPLORER Simulation Data Bus

Simulator Coupling Technology

CircuitSimulator

Block DiagramSimulator

State MachineSimulator

Simulink

MathCad

Maxwell2D/3DElectromagnetismElectro mechanics

C/C++ Interface

Model DatabaseElectrical, Blocks, States, Machines, Automotive, Hydraulic,

Mechanics, Power, Semiconductors…

VHDL-AMSSimulator

Specifications

RMxprt

ModelFEA

SimplorerECE

RMxprt Data Input

RMxprt - LINK RMxprt - LINK

A

B

C

Torque

Position

RMxprtLink1

E1

E2

A+ Torque

J

MchRMas1

STF

MchRStf1

J

MchRMas2

STF

MchRStf2

J

MchRMas3

+ V

Speed

+ V

Position

RMxprt -> SIMPLORER

BJT1

S1

Alternator

A

BC

Field

ControlfromPCM

Powertrain Control Module

3 ~MS BA

C

Battery

M

Loads

Motors,Lamps,Solenoids,Sensors,Modules

Typical Charging System: Alternator, PCM, Battery, Loads

Charging System in SIMPLORER

RLOADS

Alternator

A

B

C

FieldIGBT1

+ V

Position

Speed

RCable

D2 D3 D4

D5D6D7

R1

C_Bat

R_Dis

D8

D9

S1

Y t

CS

R_wire11

L_wire13000 RPM

A +

AM1

A+

AM2

MEAN VALUEMEAN_I_Field

MEAN VALUE

MEAN_I_Load

+ V VM1

MEAN VALUE

MEAN_Vout

SUM1.VAL > 0

42

A

B

C

Torque

Position

Field

RMxprtLink1

SET: ctrl_1:=0SET: ctrl_1:=1

D1

OPEN at 350msec

ctrl_1

AbsSUM1

FCT_ABS1

SAWTOOTHV

SUM1.VAL <= 0COMP1

S & H

Output Voltage, Average Output(X10), and Control Signal(X100)

Simulation Results

(Scaled at 100*Control Signal and 10*Average Output)

MEAN_Vout.VALVM1.Vctrl_1

t

597.38

-100.00

0

100.00

200.00

300.00

400.00

500.00

0 1.000.25 0.50 0.75

Field Current

Simulation ResultsR_WandB.I

t

20.00

-2.00

0

2.50

5.00

7.50

10.00

12.50

15.00

17.50

0 1.000.20 0.40 0.60 0.80

Add zener, adjust sawtooth frequency & duty cycle

RLOADS

Alternator

A

B

C

FieldIGBT1

+ V

Position

Speed

RCable

R_WandB D2 D3 D4

D5D6D7

R1

C_Bat

R_Dis

D8

D9

S1

Y t

CS

R_wire11

L_wire1

L_wirec

3000 RPM

A+

AM1A

+

AM2

MEAN VALUEMEAN_I_Field

MEAN VALUEMEAN_I_Load

+ V VM1

MEAN VALUEMEAN_Vout

SUM1.VAL > 0

42

A

B

C

Torque

Position

Field

RMxprtLink1

SET: ctrl_1:=0SET: ctrl_1:=1

D1

OPEN at 350msec

ctrl_1

AbsSUM1

FCT_ABS1

SAWTOOTHV

SUM1.VAL <= 0COMP1

S & H

D_Z_ST_56V1

“Bang-bang” modeDuty cycle

Design Improvement

20Hz Sampling with 90/10 PWM

Output Voltage

Average Output Voltage

Field Current

VM1.V

t

60.00

-10.000

10.00

20.00

30.00

40.00

50.00

0 5.001.00 2.00 3.00 4.00

MEAN_Vout.VAL

t

50.00

-5.000

10.00

20.00

30.00

40.00

0 5.001.00 2.00 3.00 4.00

R_WandB.I

t

12.00

0

2.00

4.00

6.00

8.00

10.00

0 5.001.00 2.00 3.00 4.00

VM1.V

t

60.00

-10.000

10.00

20.00

30.00

40.00

50.00

0 2.000.50 1.00 1.50

MEAN_Vout.VAL

t

50.00

-5.000

10.00

20.00

30.00

40.00

0 2.000.50 1.00 1.50

R_WandB.I

t

12.00

0

2.00

4.00

6.00

8.00

10.00

0 2.000.50 1.00 1.50

16Hz Sampling with 90/10 PWM

Output Voltage

Average Output Voltage

Field Current

RMxprt and SIMPLORER enable the engineer to study all thedesign alternatives quickly and without destroying or degrading the properties of valuable components. With thisinformation highly focused testing can be carried out to complete the development process.

Benefits:

Shortened development timeImproved performance and reliabilityGreater customer satisfactionLower warranty costs

Summary