3rd

International Symposium on Electrical Engineering and Energy Converters September 24-25, 2009, Suceava

137

Abstract—The purpose of this paper is to present the use of

the DMCode-MS(IM) motion control library in the MATLAB-

Simulink development environment and in the DMCD-Pro

(Digital Motor Control Developer Pro) real control system. It

presents the way of using the DMCode-MS(IM)

MATLAB/Simulink library, and of simulating in

MATLAB/Simulink different control models for asynchronous

motors. These models can then be tested on the Technosoft

MSK2812 Kit C Pro, a digital control real time system

integrated with the TMS320F2812. This state-of-the-art

development approach of digital motor control applications

implements the developers’ old dream: start with the complete

system model, design the control blocks and analyze its

expected behavior by simulation, then automatically generate

executable code for the target control system and perform the

tests on the real system. Such an approach not only

significantly reduces the development time, but also lets you

focus on the application functionality and performance, thus

shortening the road from design and laboratory phase and

from there to industrial application level.

Index Terms—asynchronous motors, digital motor control,

motion control, vector control, simulation software.

I. INTRODUCTION

The rapid pace of technology development and progress

recorded in power electronics equipment allows at the

present production of highly efficient electric drives. Rapid

development of microelectronics and informatics, has

caused major changes in the electric motor control

technology and development of digital signal processor

dedicated to control movement made possible the

widespread deployment of numerical control algorithms.

In order to practically implement a system drive, in a way

as quickly as possible, in recent years have developed a

series of specially designed software to convert a drive from

the stage of simulation in machine code for digital signal

processors dedicated to different applications.

The solution used provides many significant benefits for

the following characteristics:

� automatic generation of C code - it eliminates the

need to write C code and assembly code;

� structure modeling and visual simulation system -

can quickly change the control structure, may be made an

optimization of control parameters, simulation results are

obtained immediately;

� analysis on the DSP system - validation of the

solution on the real control environment;

� “plug-and-play” approach - the first straightforward

step is to set up the hardware and software and then you can

already test that all parts operate properly (simulation, code

generation, download and execution on DSP structure).

Fig.1 The implementation of the scheme drive system - the software

simulation stage during the execution phase on DSP.

II. MATHEMATICAL MODEL OF INDUCTION

MOTOR

To simulate some transitional processes in asynchronous

machine was used a model of induction motor based on the

theory of representative space phasor. Using theory of

representative space phasor allowed to obtain a general and

simple model of induction motor, including the most

complex operating regimes.

The use of representative space phasors simplifies the

mathematical model of the motors with cylindrical

symmetry, as is the induction motor. The main advantage is

that it facilitates the understanding of the phenomena

occurring in the motor, through the direct link between the

representative space phasor of the current and the magnetic

voltage produced by a poly-phased winding. These

advantages are best illustrated within the “field control” of

the induction motor.

With practical control systems, the use of a model with a

number of equations as little as possible is preferred, even if

its parameters present certain variations.

In developing the model were taken into account the

following simplifying assumptions:

� the motor is unsaturated;

� the iron permeability is practically infinite;

Techniques for Implementing a Model

Simulated on a Physical Drive Vector Control

Ciprian AFANASOV

"Stefan cel Mare" University of Suceava

str.Universitatii nr.13, RO-720229 Suceava

aciprian@eed.usv.ro

138

� iron losses are practically insignificant;

� only the fundamental of magnetic fields are

considered;

� the motor has a perfect electric symmetry (stator

phases have the same number of coils and the same

parameters).

Taking into account the above simplifying assumptions

and the functioning equations of the induction motor,

through computing we can obtain the following final

operating equations [1]:

u�α � R� · i�α ��Ψα�

� �Ψα� � u�α R� · i�α (1)

u�β � R� · i�β ��Ψβ�

� �Ψβ� � u�β R� · i�β (2)

u�α � R� · i�α ��Ψ�α�

� �Ψ�α� � u�α R� · i�α (3)

u�β � R� · i�β ��Ψ�β�

� �Ψ�β� � u�β R� · i�β (4)

where:

i� � i�α � j · i�β (5)

i� � i�α � j · i�β � i�� � i�α j · i�β (6)

�ω� �

�� ·

��J · L� · I��i�, i��� M�

�J (7)

�ω� �

����J L� · I� � i�α � ji�β! i�α ji�β!" M�

�J (8)

�ω� �

�� ·

��J · L� · i�β · i�α i�α · i�β! M�

�J (9)

The variable parameters to be placed in SIMULINK

block of the induction motor are:

� stator winding resistance: Rs

� rotor winding resistance: Rr

� stator winding inductance: Ls

� rotor winding inductance: Lr

� mutual inductance: Lm

� moment of inertia: J

� number of pole pairs: p

SIMULINK diagram of three phase induction motor that

was simulated is shown in Fig. 2.

III. SYSTEM SIMULATION

At this first level, the working environment MATLAB

allows complete simulation of digital systems control for

induction motors. All models block to simulate motors,

sensors, power converters, etc., are provided by software

libraries. For example, Fig. 3 presents the principle scheme

for the vector control of an three phase induction motor

operating in a speed loop.

Equivalent scheme of vector control system described in

Fig. 3 was implemented in the MATLAB-Simulink

development environment, as can be seen in Fig. 4.

A separate tuning tool can be used to set up the

controllers, based on the system parameters and imposed

control performances. Fixed-point IQ Math type is

emulated, to reproduce the real environment from the DSP

controller [2].

Once the design phase has been accomplished, simulation

of different operating conditions will allow you to evaluate

the expected behavior of the system, and to improve the

system model and/or parameters, for better performance.

At this stage you can choose optimal parameters for all

regulators, may refrain simulated waveform that basically

have no way to be measured and verified if made properly

functioning system.

If results are satisfactory, can pass to the next stage - C

code generation for the model.

M

6

teta_mech[rad]

5

omega_mech[rad/s]

4

Phira

3

Ic [A]

2

Ib [A]

1

Ia [A]

p/J

2/3

a,b,o ->ABC

Tabo2ABC

3/2

ABC ->

a,b,o

TABC2abo

1/p

Rr

Rr

Rs

Rs

Phis Is

Phir Ir

Phib ---> Ib

Phis Is

Phir Ir

Phia ---> Ia3/2*p*p/J*Lm

Irb*Isa

Ira*Isb

1

s

I_w

1

s

I_Phi_sb

1

s

I_Phi_sa

1

s

I_Phi_rb

1

s

I_Phi_ra

1

s

1

4

Mr [Nm]

3

Uc [V]

2

Ub [V]

1

Ua [V]

Fig. 2 SIMULINK diagram of three phase induction motor

3rd

International Symposium on Electrical Engineering and Energy Converters September 24-25, 2009, Suceava

139

Fig. 3 Motion control scheme of an induction motor, operating in sinusoidal mode (vector control)

Fig. 4 The vector control scheme in MATLAB-Simulink

IV. C CODE GENERATION

At this level it is generating code C/C++ for all blocks

involved in the simulated system in order that they are

implemented and tested on a DSP controller (in this case

TMS320F2812). To do this the program uses Real Time

Workshop, offered by MATLAB working environment. It

helps generate a file C/C++ complete for each of the blocks

that were used to model the control system, as seen in Fig.5.

Thus, you will get the code to be embedded on the DSP,

implementing for example coordinate transformations,

current/speed/position controllers, etc. Specific

implementation aspects as fixedpoint numerical

representation can also be applied, including scaling,

overflow and saturation. Specific numerical representations

(as the IQ Math format) can be used to generate code that

can be correctly implemented and executed at DSP level [3].

V. IMPLEMENTATION OF THE DSP REAL TIME

APPLICATION

The C code generated from MATLAB is finally included

in a basic real-time interrupt application, which can be

executed on a TMS320F2812 DSP controller based module.

Using the Digital Motor Control Developer Pro (DMCD-

Pro) IDE platform, you will be able to download and run the

application on the real digital control environment (Fig. 6).

Also this program allows you to use some graphical tools

for analysis and could thus generate a graph of motion as a

benchmark for the system and can see how varied the

parameters of the system. The values are shown graphically

are saved in a first phase the memory controller, saving is

made in real time as they are transferred to the user's

computer and displayed graphically.

At this level, you can finally compare results obtained

from system simulation with the ones obtained in the real

time application.

i_a[bits]

i_b[bits]

i_c[bits]

spd_controller0

SLIP

COMPENSATION

sl ip0

sinsin_theta

iq_controller0

id_controller0

Id_ref

i_d_ref

cos cos_theta

z

1

Unit Delay

Power

module

UQ-ref + UD_ref

[biti]

UA +UB + UC

[A]

TETA

[RAD]

Transform

dq->abc

TDQ2ABC0

Transform

abc->dq

TABC2DQ0

Speed

reference

Copy

Rate Transition

REFERINTA DE VITEZA +

VITEZA MASURATA

[counts/sampl ing]

OMEGA

[RAD/S]

0.1 Mr [Nm]

IM

Induction Motor

IQ_ref +

ID_ref

[A]

IQ_reactie

ID_reactie

IA +IB

[A]

double

double

double

double

Convert

Convert

Convert

Convert

Convert

Convert

Convert

FLUX ROTORIC

[A]

Encoder

-K-

-K-

A/D

Current Measurement

CUPLU

ELECTROMAGNETIC

omg_mech

[counts/sampling]

iq[bits]

iq[bits]

id_ref [bits]

id[bits]

uq_ref [bits]

ud_ref [bits]

ua_ref [bits]

ub_ref [bits]

uc_ref [bits]

u_a [V]

theta_mech[rad]

spd_ref

[counts/sampling]

u_b [V]

u_c [V]

iq_ref [bits]i_a[A]

i_b[A]

theta_mech[counts]

speed

[counts/sampling]

speed

[counts/sampling]

speed

[counts/sampling]

140

Fig. 5 Using Real Time Workhop for C/C++ code generation

Fig. 6 Real-time Digital Motor Control Developer-Pro IDE platform

VI. EXPERIMENTAL RESULTS

Simulation of vector drive system described in Fig.4

presents the operation of a three phase induction motor with

rotor cage prescribing a reference speed. Throughout the

simulation, the induction motor was applied to the rotor a

resistant torque of 0.05 Nm. Parameters correspond to a

induction motor with power of 370W.

Drive system includes in addition to three phase induction

motor powered by a PWM inverter, two blocks performing

transformations of axes of DQ in ABC and the ABC in DQ,

a block is to compensate the rotor slip (SLIP

COMPENSATION), a block (A / D) which is to convert the

currents of the two phase of analog to digital, and three PI

regulators. An PI block is designed for speed regulator and

the other two serve as current regulators, one for component

Iq and one for component Id.

The entire drive system simulating vector control of

induction motor through a DSP. For this reason all units

with working digital signal processor are converted into bits

and scaled with the appropriate scale factor. Scale factor is

chosen for each size separately in line with current and

speed transducers which are used basically to measure the

strength parameters of the circuit.

In Fig.7 are presented simulation results of vector drive

system. In Fig.7 a) is present in blue prescribed speed and

the green speed at which the engine worked, where 100 bits

is 3000 rpm. In Fig.7 c) are presented current response after

the component Id and the Fig.7 d) real current component

has been established for Iq.

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International Symposium on Electrical Engineering and Energy Converters September 24-25, 2009, Suceava

141

Fig. 7 a) Prescribed speed and the actual speed

of the system

Fig. 7 b) Reference of current component Iq and Id

Fig. 7 c) Current component Id

Fig. 7 d) Current component Iq

Fig.7 e) Electromagnetic torque

In Fig. 7 f) is presented as the variation of three phase

stator currents. Note that currents go to high levels during

the regimes of variation of speed between two constant

values of speed. Large amount of current is an image of

component Iq which produces torque in the motor, while the

lower value of current is an image of component Id which

produces magnetic field in the motor.

Fig.7 f) Three phase stator currents

In Fig. 8 are presented the results of practical

implementation a drive system on digital signal processor

TMS320F2812.

To make a comparison as well between the values

obtained by simulating the control system and the values

obtained by direct measurements, have been prescribed as a

reference speed of Fig.8 a), the same reference is used and

for simulation. In Fig.8 a) is presented in black prescribed

speed and with red the speed at which the engine worked.

In Fig.8 b) is presented the stator current Iq_ref and in

Fig.8 c) how the varied current Iq.

If a comparison is made between results obtained by

simulation and results are determined practically almost

finds no major differences, validating the correctness of this

vector drive system simulation.

142

Fig. 8 a) Prescribed speed and the real speed of the system

Fig. 8 b) Reference of current component Iq_ref

Fig. 8 c) Current component Iq

VII. CONCLUSION

Such a system design of drive not only significantly

reduces the development time, but also lets you focus on the

application functionality and performance, thus shortening

the road from design and laboratory phase and from there to

industrial application level.

APPENDIX A

Photographs of the experimental stand

REFERENCES

[1] K B. Bose. Power electronics and ac drives, New Jersey 07632 :

Prentice Hall.

[2] Instruments, Texas. Digital Motor Control SPRU485A. Dallas, Texas

75265 : Texas Instruments, August 2001.

[3] Technosoft. DMCode-MS(IM) MATLAB Library User Manual.

Chemin de Buchaux 38 Switzerland : Technosoft, 2006.

0 1 2 3 4 5

x1e3

-150

-75

0

75

150

Acquisition time

SpdRef Spd

0 1 2 3 4 5

x1e3

-15

-7.5

0

7.5

x1e3

Acquisition time

IqRef

0 1 2 3 4 5

x1e3

-10

-5

0

5

10

x1e3

Acquisition time

Iq