Control methods of PMSM

The presentation contains the details about Control methods of PMSM like vector control,self control and Microprocessor control

1. CONTROL METHODS OF PMSM Contents: Introduction Types of Control Vector Control of PMSM Principle of Vector control Self control of PMSM Principle of self control Micro processor control of PMSM References Kongunadu college of Engineering & Technology Control methods of PMSM

2. INTRODUCTION A p e rm a n e nt m a g n e t s y n c h r onous mo t or is a lso ca l l e d a s b r ushl e ss p e r man e nt m a g n e t sine wa ve mo t o r . A sine w a ve mo t or h a s a S inusoidal or qu a s i - sinu s oidal distribution of m a gn e t i c f lux in t he a ir ga p. S inusoidal or qu a s i - sinu s oidal c u r r e nt w a ve f o rms. Qu a s i - sinu s oidal dis t ribution of stator c o ndu c tors (i. e .) shor t - pi tc h e d a nd dis t ribut e d or c on ce ntric s t a tor w ind i ngs. The various methods of control of PMSM are discussed in this presentation Kongunadu college of Engineering & Technology Control methods of PMSM

3. Types of control of PMSM Vector control Self control Micro processor control Kongunadu college of Engineering & Technology Control methods of PMSM

4. Vector control Ele c trom a g n e t i c torq u e in a n y e l ec tri c a l ma c hine is d e v e loped due to the in t e r a c t i on of c u r r e nt c a r r y i n g a rm a tu r e c ond u c tors with t h e a ir g a p flu x . Consid e r a two m a c hine w h o s e a rm a ture c ondu c tor c u r r e nts a nd a ir g a p flux a re a s shown in f i g . H e re the flux is in qu a d ra tu r e with t he a rm a ture m m f a x is . Quadrature position of air Non- Quadrature position of air gap flux and armature mmf axis. gap flux and armature mmf axis. Kongunadu college of Engineering & Technology Control methods of PMSM

5. E ac h a nd e v e r y a rm a ture c ondu c tor e x p e ri e n c e s a fo rc e wh i c h c ontribut e s the torqu e . The torque c ontribut e d b y v a rious a rm a tu r e c ondu c t o rs h a ve the s a me di r ec t i on e v e n thro u g h t h e ir ma g ni t ude m a y v a r y . I t i s obse r v e d that t h e st e a d y s t a te a nd d y n a m i c ( behaviours ) p e r f o rm a n c e of a most of su c h a n a r ra n g e ment a re b e t t e r. Consid e r a s ec ond c a se wh e r e in the a rm a ture c o ndu c tor c u r r e nt dis t ribution a nd a ir g a p flux di s tribution a re a s shown in above fi g . I n th i s ca se the a n g l e b e tw e e n the a x is of the a ir g a p flux a nd the a rm a ture m mf a x is i s dif fe r e nt f r om 90° e le c . I n th i s ca se a lso e a c h a n d e v e r y a rm a tu r e c ondu c tor e x p e ri e n ce s a fo r c e a nd c ontribut e s to the torqu e . B ut in th i s ca se the dir e c t i on of the torque e x p e ri e n c e d b y the c ondu c tors is not the s a me. S ince c ondu c t i on d e v e lops torque in o n e d i r e c t i on while the ot h e rs d e v e lop in the opposite dir ec t i on. As a r e sul t , the r e sul t a nt torque g e ts r e d u ce d; c onse q u e nt l y it is obse r v e d that both the ste a d y s t a te a nd d y n a m i c p e r f o r ma n c e o f su c h a m otor is poor e r. Kongunadu college of Engineering & Technology Control methods of PMSM

6. principle of vector control B L P M S NW mo t or is usual l y e mp l o y e d for v a ri a ble spe e d a ppl i ca t i ons. F or th i s we k e e p V/f c onst a nt and v a r y V a nd f to g e t t he d e si r e d s p ee d a nd torq u e .   F rom the theo r y of B L P M S NW mo t or i t is kn o wn that a s the spe e d is v a ri e d f r om a v e r y low v a lue up to the c o r n e r f r e qu e n c y , the d e si r e d o p e r a t i n g point of c u r r e nt is s u c h that I d = a nd I is a long the q -a x is. S u c h a c ondi t ion ca n be a c hiev e d b y sui t a b l y c ont r ol l ing the vol ta ge b y PW M t ec hnique a ft e r a d j ust i ng the f r e qu e n c y to a d e sir e d v a lue.   W h e n the f re qu e n c y is more than the c o r n e r f r e qu e n c y it is not pos s ib l e to make I d = 0, due to the vol t a ge c onst r a in t s. I n s u c h a c a se a b e t t e r op e r a t i n g point for c u r r e nt is obtain e d with m i ni m um I d v a lue a ft e r s a t i s f y i n g the vol ta g e c o n str a in t s. Controlling B L P M S NW mo t o r taking in t o c onsid e r a t i on the a bove mentioned a spe c ts is known a s v ec tor Control of B L P M S NW mo t o r . Kongunadu college of Engineering & Technology Control methods of PMSM

7. Schematic diagram of vector control The s c h e matic bl o c k di a g r a m of v e c tor c ontrol i s a s shown in fi g u re Kno w ing the v a lue of the d e sir e d tor q ue a nd spe e d a nd a lso the p a r a met e rs a nd the vol ta ge to whi c h the mo t or is subj ec ted to, it is poss i ble to c omp l e te the v a l u e s of i d . r e f a nd i q . r e f for the d e sir e d d y n a m i c a nd ste a d y s t a te p e r fo r ma n ce . Kongunadu college of Engineering & Technology Control methods of PMSM

8. SELF CONTROL OF PMSM S e lf -c ontrol e nsur e s that for a ll op e r a t i n g poin t s the a rm a ture a nd rot o r fi e lds move e x ac t l y a t t h e s a me s p ee d . The torque a n g le is a dj u sted e le c tron i ca l l y h e n c e the r e is a n a ddi t ional c ontroll a ble p a r a met e r p a ss i ng g re a ter c ontrol of t he mo t or behaviour b y c h a n g i n g the f i ring o f the s e m i -c ondu c tor switc h e s of a n inve r t e r .   The torque a n g le is s a i d e le c troni c a l l y h e n c e t he fund a men t a l c ompo n e nt of ph a s e A n ee ds Φ f /β, it l i e s a long the dir ec t a x is that rot a t e s a t a s y n c h r onous sp e e d . The switch e s must be trig g e r e d b y p h a se A c u r r e nt c omponent wh e n Φf a x is is β e le c tric a l d e g r e e s b e hind the ph a se A a x is. This is ac hiev e d by fi r i n g the switch wh e n dir ec t a x is is δ + β b e h ind a x is of A Kongunadu college of Engineering & Technology Control methods of PMSM

9. Schematic diagram of self-control Self-control is applicable to all variable frequency converters, the frequency being determined by machine. At hi g h pow e r le v e ls the most c om m on pow e r c o n v e rt e r c onf i g u r a t i on is t h e c u r re nt f e d DC l i nk c onv e rt e r Kongunadu college of Engineering & Technology Control methods of PMSM

10. MICROPROCESSOR BASED CONTROL OF PMSM The a d v e nt of m i c rop r o ce ssor h a s r a ised in t e r e s t in di g i t a l c ontrol of p ow e r c onv e r t e r s y stems a nd e l ec troni c s mo t or d r ives since the m ic r oproc e ssor p r ovides a fl e x ib l e a nd low c ost a l t e rn a t i ve to t he c on v e n t ional method. Kongunadu college of Engineering & Technology Control methods of PMSM

11. The main fun c t i ons of the m i c rop r o ce ssor a re mon i toring a nd c ontrol of the s y stem v a ri a bles for the pur p ose of obtaining desir e d dri v e f e a tur e s . I t c a n a lso p e r fo r m va r ious a u x i l ia r y tasks such a s p rot ec t i on, dia g nosis a nd disp l a y . I n norm a l op e r a t i on, c om m a nds a r e f e tch e d f r om the inpu t - output te r m i n a ls, a nd s y stem v a ri a bles (the dc l i nk c u r r e nt, the rotor posit i on a nd spe e d) a re s e nsed a nd fe d to the C P U . A f t e r p r o c e ss i n g , the m i c rop r o ce s s or is s u e s c ontrol s i g n a l to the input r ec t i fi e r, t h e n the m ac hine inve r t e r, so a s to p rovide t h e p r o g r a m m e Kongunadu college of Engineering & Technology Control methods of PMSM

12. REFERENCES S.No Books / Web Sources 1. K.Venkataratnam , ‘Special Electrical Machines’, Universities Press (India) Private Limited, 2008 2. T.J.E. Miller, ‘Brushless Permanent Magnet and Reluctance Motor Drives’, Clarendon Press,Oxford , 1989. 3. T. Kenjo , ‘Stepping Motors and Their Microprocessor Controls’, Clarendon Press London, 1984. 4. R.Krishnan , ‘Switched Reluctance Motor Drives – Modeling, Simulation, Analysis, Design andApplication ’, CRC Press, New York, 2001. 5. P.P. Aearnley , ‘Stepping Motors – A Guide to Motor Theory and Practice’, Peter Perengrinus ,London, 1982. 6. T. Kenjo and S. Nagamori , ‘ Permanent Magnet and Brushless DC Motors’, Clarendon Press, London, 1988. 7. K.Dhayalini , “Special Electrical Machines,” Anuradha Publications, 2017. 8. Google and Wikipedia Kongunadu college of Engineering & Technology Control methods of PMSM