Fuzzy controller for inverter fed induction machines

Abstract

Phone (2 16)972-7649 Fax (2 16)972-6487 A bsfruct-A n i n d u c t i o n machine operated w i t h a d i r e c t s e l f c o n t r o l l e r ( D S C ) shows a s l u g g i s h response d u r i n g s t a r t u p a n d u n d e r changes o f t o r q u e command. Fuzzy logic is used in c o n j u n c t i o n w i t h d i r e c t self c o n t r o l t o m i n i m i z e these problems. A fuzz! logic con t r o I le r c 11 ooses t Ii e swi t c Ii i n g st a tes based o n a set o f fuzzy variables. Flux position, e r r o r in flux m a g n i t u d e a n d e r r o r in torque a r e used as fuzzy state variables. Fuzzy rules are determined b y o b s e r v i n g t h e v e c t o r d i a g r a m o f f l u x a n d c u r r e n t s . T h e o p e r a t i o n o f t h e d i r e c t self c o n t r o l l e r becomes d i f f i c u l t a t low speeds due t o the effect o f c h a n g e i n s t a t o r r e s i s t a n c e o n t h e f l u x measurements. T o i m p r o v e the system p e r f o r m a n c e a t low speeds a f u z z y r e s i s t a n c e e s t i m a t o r is proposed t o eliminate t h e e r r o r d u e to the the change i n s t a t o r resistance. A t constant f l u x a n d t o r q u e commands a n y change in s t a t o r resistance o f t h e i n d u c t i o n machines causes a n e r r o r in s t a t o r c u r r e n t . T h i s e r r o r i s u t i l i z e d b y t h e f u z z y resistance e s t i m a t o r t o c o r r e c t t h e s t a t o r resistance u s e d b y t h e c o n t r o l l e r t o m a t c h t h e m a c h i n e r e s i s t a n c e . B o t h f u z z y c o n t r o l l e r a n d fuzzy resistance e s t i m a t o r a r e s i m u l a t e d f o r a 3 h p i n d u c t i o n motor. T h e s i m u l a t i o n r e s u l t s d e m o n s t r a t e :I g o o d p e r f o r m a n c e .

Robustness Analysis on Sliding Mode Control of Induction Motor

“…These coefficients depend explicitly on the machine parameters, which are not precisely known since they are very sensitive to rising temperature and saturation effects. Hence, the control low (7) may fail in making the manifold ( ( ) ( )) T e e Ψ = Ψ Ψ attractive and invariant. This means that, flux-speed tracking may not be achieved.…”

“…Another approach consists in exploiting the non-linear controls, which essentially incorporate properties of robustness. One can initially quote the H ∞ control [5,6], the fuzzy logic control [7,8]. For our case one is interested in the sliding modes control.…”

Modeling and Experimental Verification of ANN Based Online Stator Resistance Estimation in DTC-IM Drive

“…It means for constant torque and flux command, stator current is dependent only on the stator resistance of the motor. So any variation in stator current indicates the variation in stator resistance [31,35] and also there is a nonlinear relationship between stator current and stator resistance [31,34]. The basic structure for stator resistance adaptation described by Fig.…”

Emotional Learning Based Intelligent Controllers for Rotor Flux Oriented Control of Induction Motor

“…However, the application of FLC has been facing some disadvantages during hardware and software implementation due to its high computational burden [7]. That is why so far the reported fuzzy logic works in motor drives [8][9][10][11][12] are mainly theoretical and based on either simulation or experimental results at very low speed operating conditions. With referring to above mentioned approaches it is clear up that fuzzy-logic control utilization to design speed control system of induction motor, rapidly increasing because of the good performance of this controller both in nonlinear and complex systems.…”