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Field-Oriented Control of Induction Machine

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Presentation on theme: "Field-Oriented Control of Induction Machine"— Presentation transcript:

1 Field-Oriented Control of Induction Machine
Dr. Nik Rumzi Nik Idris Department of Energy Conversion, Faculty of Electrical Engineering, Universiti Teknologi Malaysia

2 Why FOC ? IM is superior to DC machine with respect to size, weight, inertia, cost, speed DC motor is superior to IM with respect to ease of control High performance with simple control due de-coupling component of torque and flux FOC transforms the dynamics of IM to become similar to the DC motor’s – decoupling the torque and flux components

3 Basic Principles DC machine
By keeping flux constant, torque can be controlled by controlling armature current Current in Current out a f Te = k If Ia

4 Basic Principles of IM s r Stator current produce stator flux
Stator flux induces rotor current  produces rotor flux Interaction between stator and rotor fluxes produces torque Space angle between stator and rotor fluxes varies with load, and speed

5 FOC of IM drive Torque equation : In d-q axis :

6 FOC of IM drive In d-q axis : Choose a frame such that:

7 FOC of IM drive Choose a frame such that:

8 FOC of IM drive Choose a frame such that: qs
As seen by stator reference frame: ds

9 FOC of IM drive Choose a frame such that: qs Rotating reference frame:
qr dr ds

10 FOC of IM drive To implement rotor flux FOC need to know rotor flux position: (i) Indirect FOC Synchronous speed obtain by adding slip speed and rotor speed Rotor voltage equation: Rotor flux equation:

11 FOC of IM drive - indirect
d component q component

12 FOC of IM drive - indirect
d component q component

13 FOC of IM drive - indirect
ia* irsq* isq* ib* CC VSI 2/3 ej irsd* isd* * ic* 1/s slip r + + Rotating frame Stationary frame

14 FOC of IM drive (ii) Direct FOC
Rotor flux estimated from motor’s terminal variables Rotor flux can be estimated by: Express in stationary frame

15 FOC of IM drive (ii) Direct FOC d q

16 FOC of IM drive - direct ia* T* isq* TC ib* CC 2/3 ej VSI r* isd*
irsq* isq* TC ib* CC VSI 2/3 ej r* irsd* isd* ic* FC r Te  Rotating frame Stationary frame


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