Lecture 7 8 Synchronous Motor

Palestine Polytechnic University

Workshop Matlab/Simulink in Drives and Power electronics – Lecture 7-818-21 May 2009 / 19

WorkshopMatlab/Simulink in Drives

and Power electronics

Lecture 7: Synchronous Motor Modeling

Lecture 8: Synchronous Motor Control

1

Ghislain REMY Jean DEPREZ



Workshop Programe• 8 lectures will be presented based on Matlab/Simulink :

– 1 Introduction to Matlab

– 2 Introduction to Simulink

– 3 DC-Motor Control design

– 4 DC-Motor Chopper design SimPowerSystems

– 5 Introduction to Stateflow/Statechart

– 6 Induction Motor Inverter Control

– 7 Synchronous Motor Modeling

– 8 Synchronous Motor Control

• Two system applications (four quadrants electric drives of mechanical systems) will be used as “guidelines" during the workshop.

2



Summary• Presentation of Synchronous Motors

• Surface Mounted PM SM model in abc frame (+vector design)

• In dq frame

• Using SimPowerSystems

• Comparison of the three models results

3



Presentation of Synchronous Motors• Various representations of PMSM in SimPowerSystems

4



Fixed Coil+ 50Hz Current Pulse Field

Pulse Field



Ferraris Principle: The sum of 3 Pulse Fields,

120o Shifted, of 3-phases currents

Rotating Field

1847–1897

Rotating Field: Principle

http://fr.wikipedia.org/wiki/Fichier:Galileo_Ferraris.jpg



Rotating Field: Vector Representation



Influence of Pole Pairs



Ω = ωp

If p is increasing Ω will decrease

With a fixed ω,

Pole Pairs: p

At 50Hz At 60Hz

p t/min p t/min

1 3000 1 3600

2 1500 2 1800

3 1000 3 1200

4 750 4 900

5 600 5 720



Model example in causal representation• Causal Representation is based on a decomposition of all the

3-phase electrical part of the PMSM

• Using the From Tag and Goto Tag

10



Trapezoidal Back-Electromotive force• Using the Lookup Table for the

back-electromotive force generation

11



The Park Transform• Main idea is to change from the stationary frame to the rotary

frame Sinusoidal signal with constant amplitude Using the Park Transform ( Remove the sin() ) Constant value only in the dq frame

12

( ) ( ) ( )( ) ( ) ( )

cos cos 2 / 3 cos 2 / 32

sin sin 2 / 3 sin 2 / 33

1/ 2 1/ 2 1/ 2

e e e

e e ePθ θ π θ π

θ θ π θ π

− +

= − − − − +

abc framedq frame



PMSM in dq frame

13



Example of PMSM• The power_simplealt shows a Simplified Synchronous

Machine block with a 1000 MVA, 315 kV, 60 Hz equivalent source connected to an infinite bus (Three-Phase Programmable Voltage Source block).– The Simplified Synchronous Machine (SI Units) block is used as a

synchronous generator.

– The internal resistance and reactance are set respectively to 0.02 pu (1.9845 Ω) and 0.2 pu (X = 19.845 Ω; L = 0.0526 H).

– The inertia of the machine is J = 168,870 kg.m2, corresponding to an inertia constant H = 3 s. The electrical frequency is ωs = 2*π*60/2 = 377 rad/s.

– The machine has two pairs of poles such that its synchronous speed is 2*π*60/2 = 188.5 rad/s or 1800 rpm.

14



Using the Bus Selector

15



Synchronous Machine block in motor mode• The power_syncmachine demo illustrates the use of the

Synchronous Machine block in motor mode. – The simulated system consists of an industrial grade synchronous

motor (150 HP (112 kVA), 762 V) connected to a network with a 10 MVA short-circuit level.

– In order to start simulation in steady state, the machine is initialized using the Load Flow and Machine Initialization option of the Powergui. The machine is initialized for an output electrical power of -50 kW (negative value for motor mode), corresponding to a mechanical power of -48.9 kW.

– The corresponding values of mechanical power and field voltage have been automatically entered by the Load Flow analysis into the Pm Step block and in the Vf Constant block.

16



Synchronous Machine block in motor mode• Using the simulation to observe the RMS current, RMS

voltage, speed, load angle δ, and output electrical power of the motor.

17



PM Synchronous 3HP Motor Drive• ac6_example: PM Synchronous 3HP Motor Drive

18



PI Gain Calculator

19

Lecture 7 8 Synchronous Motor

Documents