Starter

Starter as a DC motor

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Libraries:
Powertrain Blockset / Energy Storage and Auxiliary Drive / Starter

Description

The Starter block implements a starter assembly as a separately excited DC motor, permanent magnet DC motor, or series connection DC motor. The motor operates as a torque source to an internal combustion engine.

Use the Starter block:

• In an engine model with a front-end accessory drive (FEAD)

• To model engine start and stop scenarios

The Starter block supports only an angular speed input to the DC motor. A load torque input requires engine dynamics.

Separately Excited DC Motor

In a separately excited DC motor, the field winding is connected to a separate source of DC power.

The relationship between the field winding voltage, field resistance, and field inductance is given by:

$V_f=L_f\frac{d{i}_f}{dt}+R_f{i}_f$

The counter-electromotive force is a product of the field resistance, mutual inductance, and motor shaft angular speed:

$EMF=L_a{i}_f{L}_{af}\omega$

The armature voltage is given by:

$V_a=L_a\frac{d{i}_a}{dt}+R_a{i}_a+ EMF$

The starter motor current load is the sum of the field winding current and armature winding current:

$i_{load}= i_f+ i_a$

The starter motor shaft torque is the product of the armature current, field current, and mutual inductance:

$T_{mech}= i_a{i}_f{L}_{af}$

Permanent Magnet DC Motor

In a permanent magnet DC motor, the magnets establish the excitation flux, so there is no field current.

The counter-electromotive force is proportional to the motor shaft angular speed:

$EMF= K_t\omega$

The armature voltage is given by:

$V_a=L_a\frac{d{i}_a}{dt}+R_a{i}_a+ EMF$

The starter motor current load is equal to the armature winding current:

$i_{load}= i_a$

The starter motor shaft torque is proportional to the armature winding current:

$T_{mech}= K_t{i}_a$

Series Excited DC Motor

A series excited DC motor connects the armature and field windings in series with a common DC power source.

The counter-electromotive force is a product of the field and armature initial series current, field, and armature mutual inductance and motor shaft angular speed:

$EMF=i_{af}{L}_{af}\omega$

The field and armature winding voltage is given by:

$V_{af}=L_{ser}\frac{d{i}_{af}}{dt}+R_{ser}{i}_{af}+ EMF$

The starter motor current load is equal to the field and armature series current:

$i_{load}= i_{af}$

The starter motor shaft torque is the product of the squared field and armature series current and the field and armature mutual inductance:

$T_{mech}= i_{af}^2{L}_{af}$

For motor stability, the motor shaft angular speed must be greater than the ratio of the series connected field and armature resistance to the mutual inductance:

$\omega >-\frac{R_{ser}}{L_{af}}$

Power Accounting

For the power accounting, the block implements these equations.

Bus Signal			Description	Variable	Equations
PwrInfo	PwrTrnsfrd — Power transferred between blocks Positive signals indicate flow into block Negative signals indicate flow out of block	PwrMtr	Mechanical power	Pmot	$P_{mot}= -\omega T_{mech}$
		PwrBus	Electrical power	Pbus	Separately excited DC motor $P_{bus}= v_a{i}_a+v_f{i}_f$
					PM excited DC motor $P_{bus}= v_a{i}_a$
					Series excited DC motor $P_{bus}= v_{af}{i}_{af}$
	PwrNotTrnsfrd — Power crossing the block boundary, but not transferred Positive signals indicate an input Negative signals indicate a loss	PwrLoss	Motor losses	Ploss	$P_{loss}= -(P_{mot}+P_{bus}-P_{ind})$
	PwrStored — Stored energy rate of change Positive signals indicate an increase Negative signals indicate a decrease	PwrInd	Electrical inductance	Pind	Separately excited DC motor $P_{ind}= L_f{i}_f\frac{d{i}_f}{dt}+L_a{i}_a\frac{d{i}_a}{dt}$
					PM excited DC motor $P_{ind}= L_a{i}_a\frac{d{i}_a}{dt}$
					Series excited DC motor $P_{ind}=L_{ser}{i}_{af}\frac{d{i}_{af}}{dt}$

The equations use these variables.

Ra	Armature winding resistance
La	Armature winding inductance
EMF	Counter-electromotive force
Rf	Field winding resistance
Lf	Field winding inductance
Laf	Field and armature mutual inductance
ia	Armature winding current
if	Field winding current
Kt	Motor torque constant
ω	Motor shaft angular speed
Va	Armature winding voltage
Vf	Field winding voltage
Vaf	Field and armature winding voltage
iaf	Field and armature series current
Rser	Series connected field and armature resistance
Lser	Series connected field and armature inductance
iload	Starter motor current load
Tmech	Starter motor shaft torque

Examples

Build Conventional Vehicle Model

Build a vehicle with an internal combustion engine using the conventional vehicle reference application.

Ports

Inputs

MtrSpd — Angular speed

scalar

Motor shaft angular speed, in rad/s.

StartVolt — Armature and field voltage

scalar

• Armature winding voltage V_a and field winding voltage V_f, in V.

• In series excited DC motor, armature and field winding voltage V_af.

Output

Info — Bus signal

bus

Bus signal containing these block calculations.

Signal			Description	Units
ArmCurr			Armature winding current	A
FldCurr			Field winding current	A
PwrInfo	PwrTrnsfrd	PwrMtr	Mechanical power	W
		PwrBus	Electrical power	W
	PwrNotTrnsfrd	PwrLoss	Motor power loss	W
	PwrStored	PwrInd	Electrical inductance	W

LdCurr — Starter motor load current

scalar

Starter motor load current, in A.

MtrTrq — Starter motor shaft torque

scalar

Starter motor shaft torque, in N·m.

Parameters

Configuration

Motor Type — Select motor type

Separately Excited DC Motor (default) | Permanent Magnet Excited DC Motor | Series Connection DC Motor

Select one of the three motor types.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	machine_type
Values:	Separately Excited DC Motor (default) | Permanent Magnet Excited DC Motor | Series Connection DC Motor
Data Types:	character vector

Dependencies

The table summarizes the motor parameter dependencies.

Motor Type	Enables Motor Parameter
Separately Excited DC Motor	Armature winding resistance, Ra
	Armature winding inductance, La
	Field winding resistance Rf
	Field winding inductance, Lf
	Mutual inductance, Laf
	Initial armature and field current, Iaf
Permanent Magnet Excited DC Motor	Armature winding resistance, Rapm
	Armature winding inductance, Lapm
	Torque constant, Kt
	Initial armature current, Ia
Series Connection DC Motor	Total resistance, Rser
	Total inductance, Lser
	Initial current, Iafser
	Mutual inductance, Lafser

Separately Excited DC Motor

Armature winding resistance, Ra — Resistance

1 (default) | scalar

Armature winding resistance, in ohm.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Ra
Values:	1 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Separately Excited DC Motor for the Motor Type parameter.

Armature winding inductance, La — Inductance

.1 (default) | scalar

Armature winding inductance, in H.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	La
Values:	.1 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Separately Excited DC Motor for the Motor Type parameter.

Field winding resistance, Rf — Resistance

.3 (default) | scalar

Field winding resistance, in ohm.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Rf
Values:	.3 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Separately Excited DC Motor for the Motor Type parameter.

Field winding inductance, Lf — Inductance

.2 (default) | scalar

Field winding inductance, in H.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Lf
Values:	.2 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Separately Excited DC Motor for the Motor Type parameter.

Mutual inductance, Laf — Inductance

.3 (default) | scalar

Mutual inductance, in H.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Laf
Values:	.3 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Separately Excited DC Motor for the Motor Type parameter.

Initial armature current and field current, Iaf — Current

[0 0] (default) | vector

Initial armature and field current, in A.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Iaf
Values:	[0 0] (default) | vector
Data Types:	double

Dependencies

To enable this parameter, select Separately Excited DC Motor for the Motor Type parameter.

Permanent Magnet Excited DC Motor

Armature winding resistance, Rapm — Resistance

.5 (default) | scalar

Armature winding resistance, in ohm.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Rapm
Values:	.5 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Permanent Magnet Excited DC Motor for the Motor Type parameter.

Armature winding inductance, Lapm — Inductance

.1 (default) | scalar

Armature winding inductance, in H.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Lapm
Values:	.1 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Permanent Magnet Excited DC Motor for the Motor Type parameter.

Torque constant, Kt — Motor torque constant

.1 (default) | scalar

Motor torque constant, in N·m/A.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Kt
Values:	.1 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Permanent Magnet Excited DC Motor for the Motor Type parameter.

Initial armature current, Ia — Current

.1 (default) | scalar

Initial armature current, in A.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Ia
Values:	.1 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Permanent Magnet Excited DC Motor for the Motor Type parameter.

Series Connection DC Motor

Total resistance, Rser — Resistance

.1 (default) | scalar

Series connected field and armature resistance, in ohm.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Rser
Values:	.1 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Series Excited DC Motor for the Motor Type parameter.

Total inductance, Lser — Inductance

.1 (default) | scalar

Series connected field and armature inductance, in H.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Lser
Values:	.1 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Series Excited DC Motor for the Motor Type parameter.

Initial current, Iafser — Current

0 (default) | scalar

Initial series current, in A.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Iafser
Values:	0 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Series Excited DC Motor for the Motor Type parameter.

Mutual inductance, Lafser — Inductance

.3 (default) | scalar

Field and armature mutual inductance, in H.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	Lafser
Values:	.3 (default) | scalar
Data Types:	double

Dependencies

To enable this parameter, select Series Excited DC Motor for the Motor Type parameter.

References

[1] Krause, P. C. Analysis of Electric Machinery. New York: McGraw-Hill, 1994.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2017a