MONITORING THE VARIATION OF SPEED FOR SINGLE PHASE INDUCTION MOTOR USING ANTI PARALLEL BACK TO BACK CONNECTED SILICON CONTROLLED RECTIFIER

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1 Proceeding o the International Conerence on Mechanical Engineering and Renewale Energy 5 (ICMERE5) 9 Novemer, 5, Chittagong, Bangladeh ICMERE5-PI-79 MONITORING THE ARIATION OF SPEED FOR SINGLE PHASE INDUCTION MOTOR USING ANTI PARALLEL BACK TO BACK CONNECTED SILICON CONTROLLED RECTIFIER Mrinmoy Dey,*, Sada Nehal and Ai Imran 3-3 Department o Electrical and Electronic Engineering, Chittagong Univerity o Engineering and Technology Chittagong-39, Bangladeh,* mrinmoycuet@gmail.com, adanehal@yahoo.com, 3 aiimran_cuet@yahoo.com Atract- Silicon Controlled Rectiier (SCR) i one o the mot powerul power electronic device which are ued in variou appliance in our daily lie. Thee rectiier are alo called phae controlled rectiier or thyritor and are widely ued or it lower on-conduction loe, eaily availaility, lower witching loe, higher eiciency and a large percentage o cot-eectivene. The eiciency o thee rectiier are almot 9% and are ued extenively in indutrial and houehold application, motly in variale-peed drive rom minimum hore-power motor to maximum hore power motor. In thi reearch paper, uch kind o peed drive are explained a it i decried here how to vary the peed o ingle phae induction motor uing anti-parallel ack to ack connected thyritor. The anti-parallel ack to ack thyritor are connected in the tator ide o the induction motor. The voltage control method are applied here or controlling peed ecaue the output voltage o thyritor i varied y controlling the iring angle o it and it can e turned on y applying a hort pule into it gate. A zero croing detection circuit are deigned or detecting the tarting o the input voltage. Then the microcontroller i programmed or generating iring angle in a particular equence that are hown in the paper. The iring angle are ed to the gate o the thyritor or conduction. Depending on the conduction angle and iring angle, the output voltage, torque and peed are varied which i our goal in thi reearch work. Moreover, the relationhip among the voltage, peed and iring angle are alo evaluated and graphically repreented. Keyword: Antiparallel ack to ack connected SCR, Single phae induction motor, variation o gate pule, iring angle, peed control.. INTRODUCTION Speed control o induction motor i required a it i widely ued in variou indutrie and houehold application. Induction motor are ued world-wide ecaue o it implicity, ruggedne and low cot. The dierence etween ingle phae and three phae induction motor i that ingle phae induction motor in t el-tarting. Single phae induction motordoen t have any revolving magnetic lux. For making it el-tarting, an extra winding known a auxiliary winding i provided with the main winding. The two winding are 9 electrically apart and are connected in parallel acro the ingle phae upply.split-phae and capacitor-tart motor are the example o two valuale ingle phae induction motor.ariou method are adopted or controlling the peed o induction motor uch a voltage control, voltage/requency control adding rheotat in tatorand changing the pole o the induction motor. Depending on the method variou technique are applied or peed control, variou technique are applied or peed control, the recent voltage control method that ha een dicovered or controlling peed i connecting anti-parallel ack to ack connected thyritor in the tator ide o the induction motor. Dierent equence o pule in variou iring angle are given to the gate o thyritor. By varying the iring angle, the output voltage change and that why peed alo change ecaue peed and voltage have proportionality. Speed control o induction motor i quite diicult ecaue o it decreaing eiciency and lower power actor. Inductive nature o the load i reluctant to the change o current. Shukla and Tripathi invetigated the peed o induction motor y varying iring angle o thyritor in 3[]. Mot o the

2 work done y them through imulation. Firing angle o induction motor wa varied y varying the potentiometer value which wa connected with microcontroller. In, a review journal paper wa pulihed aed on the peed control technique o induction motor y variale requency drive ytem []. In thi journal, the technique o peed control were hown like that olt/hertz control, how to adopt FD method. The load characteritic like contant torque load, contant hore-power load, variou type o inverter, cycloconverter and PWM method were alo hown in thi journal. In 3,a journal wa pulihed on the topic o peed control method o induction motor y cycloconverter with thyritor in which it wa decried aout the cycloconverter, it ue and it wa hown rom the paper that, cycloconverter produced one requency ac voltage rom dierent requency ac voltage[3]. Moreover, cycloconverter can handle load o variou power actor and allowed to low power in variou direction. Eicient ine wave output wa produced in low requencie. Another journal paper wa pulihed in y Suneeth and Uha on peed control o ingle phae induction motor uing AC chopper y aymmetrical PWM method in which PWM method wa ued to witch on IGBT. The goal o that reearch wa to maintain the peed contant in dierent load condition y uing aymmetrical PWM method. It wa ued to reduce harmonic too[]. In our reearch work, the peed control o ingle phae induction motor uing anti parallel ack to ack connected thyritor are done via dierent technique rom other reearch work. The gate pule that are ed y the microcontroller are programmed in a equential manner. Gate pule are generated careully o that the iring equence will e maintained. We invetigated the controlling o peed o ingle phae induction motor with repect to varying iring angle. Moreover, relationhip among iring angle, generated voltage and peed i hown.. METHODOLOGY Method or controlling the peed o induction motor are voltage/requency control method, voltage control method, adding rheotat in the tator ide o the motor, adding and changing the numer o pole. Among the method, voltage/requency control method and voltage control method are requently ued or controlling peed. In thi reearch work tator voltage control method are adopted.firt o all, the ynchronou peed i deined a N () P Where, N i the ynchronou peed in r.p.m, P i the numer o pole. Now, the peed o induction motor ecome, N N ( ) () m Where i thelip andn m i the rotor peed in r.p.m. The torque produced in induction motor i E R R ( X ) T= (3) Where, E i the induced voltage in the rotor ide in volt, R i the rotorreitance in ohm, X i the rotor leakage reactance in ohm and N N = contant So, rom the equation o torque aove, it i oerved that torque i related proportional to the rotor voltage. The peed which alo ha the proportional relation with the torque, that mean it alo proportional relation with voltage. So, peed will change with the change o induced voltage in the rotor. Another important criteria o the ingle phae motor i that rom the deinition o doule ield revolving theory, the alternating lux can e looked upon a compoed o two revolving luxe, each o hal the value and revolving ynchronouly in oppoite direction[5]. I the lip o the rotor with repect to orward rotating lux i and i the lip with repect to ackward rotating lux then, In thi method, the peed are regulated y varying the iring angle o the thyritor pair. AC T R T () Fig.: Schematic diagram or propoed method The pulatic waveorm or iring angle α=3 that are given in the gate o dierent thyritor are hown elow:- T T Fig.: Gate pule or T &T in the range o α=3 The pulatic waveorm or iring angle α= that are given in the gate o dierent thyritor are hown elow:- C M

3 T T Fig.3: Gate pule or T &T in the range o α= The pulatic waveorm or iring angle α=9 that are given in the gate o dierent thyritor are hown elow:- T T Fig. : Gate puleor T &T in the range o α=9 Gate pule or remaining delay i generated in identical manner. A mentioned earlier, the equence o gate pule are hiting right direction with the increaing delay angle. Thoe gate pule will chop the incoming line voltage and thee chopped inuoidal voltage will e provided to tator circuit o the ujected motor. Hence with an increaing delay angle a decreaing peed will e otained. 3. RESULTS AND ANALYSIS For thi reearch work a, W, pole ingle phae induction motor ha een ued to oerve peed regulation uing antiparallel ack to ack connected thyritor. The value o iring angle, peed and voltage ha een taken. Dierent value o parameter are compared and power lo ha een calculated individually or ingle phae induction motor. The comparion o iring angle, generated voltage andpeed are hown dierently or ingle phae induction motor in tale I: TABLE I. RELATION AMONG ARIOUS FIRING ANGLE, OLTAGE AND SPEED Firing angle, α (Degree) Terminal oltage, t(olt) Motor Speed,N m (R.p.m) It i oerved rom the relationhip that with the increaing o iring angle generated voltage i decreaed that caue the alling o the peed o ingle phae induction motor. Fig. how that the voltage drop doen t decreae linearly. The voltage ha een dropped dratically with the increae o iring angle o the thyritor pair. Terminal oltage,t(olt) Fig. 5: Firing anglev Terminal oltage curve In Fig.5voltage ha een plotted with repect to iring angle and it oerved that or the range o -3 o iring angle, voltage decreae almot linearly in a lower rate. Again or the variation o delay angle within 3 -, voltage change rapidly than the prior. Fig. how the relation etween peed and iring angle. Motor Speed,Nm(rpm) Motor Speed,Nm(rpm) Fig. : Firing angle v Motor Speed curve Terminal oltage,t(olt) Fig.7: Terminal oltage v Motor Speed curve

4 TABLE II. CALCULATION OF POWER LOSS FOR DIFFERENT FIRING ANGLE Evaluated Parameter α=3 α= α=9 α= Stator current, I tator(ampere) Forward Rotor current, I r (Ampere) Backward Rotor current,i r (Ampere) Input power, P in (Watt) Power Factor, coθ Forward torque,t (N-m) Backward torque, T (N-m) Slip with repect to orward rotating lux,s Slip with repect to ackward rotating lux,s Output power, P out (Watt) Power lo (Watt) From the graphical repreentation and tale that are hown aove it i een that with increaing iring angle, the output voltage i decreaing. Speed which i dependent on the output voltage i alo decreaing in the ame manner hown in Fig. 7. In our reearch work 5tep are hown ecaue ater iring angle the output voltage ecome zero or which no peed i ound. Power actor,co(angle) Fig. 8: Firing angle Power Factor Curve In the Fig. 8 the relationhip etween iring angle and power actor i demontrated. Power actor increae to a certain level or increaing the iring angle and then egin to decreae a like a power lo. Here rom the equivalent diagram, it i oerved that the rotor are plit into two portion. One i the orward portion and the other i the ackward. The Forward impedance, And the Backward impedance, I j( r /( ) jx) r j( x) r j ( jx) r j( x) (5) () (7) I (8) total r ( x (9) r ) r ( r /( )) x ; ()

5 I r r, I r r () From the calculation o ingle phae induction motor peed control, it i ound that y increaing the iring angle o the thyritor peed, voltage and the mot importantly it eiciency i decreaing. R X r/ Motor, International Journal o Computer Techology & Electronic Engineering,vol., no. 5, Octoer. [3] Sathih Bakanagari, Jagadeh Peddapudiand A. Maheh Kumar, A Novel Approach to Speed Control o Induction Motor y Cycloconverter with Thyritor, International Journal o Engineering reearch & Application, vol. 3, no., Nov-Dec. 3. [] R.Suneeth and P. Uha, Speed Control o Single Phae Induction Motor Uing AC Chopper y Aymmetrical PWM method, International Journal o Advanced Reearch in Electrical, Electronic Intrumentation,vol. 3, no., Octoer. [5] B.L. Theraja and A.K. Theraja, A Textook o Electrical Technology, olumer II. AC x r/(-) x Fig. 9: Equivalent diagram o ingle phae induction motor. CONCLUSION Controlling the peed o induction motor y uing thyritor ha one o the great advantage that it i a very precie proce or controlling peed ecaue thyritor are very at witching and availale power electronic device. It een that peed or voltage will e decreaed i delay angle i made higher than the prior. The peed will e changed a oon a the iring angle i changed. It i a antatic method or low power induction motor or controlling peed. It it meticulouly where teeper drop o peed i required. 5. ACKNOWLEDGMENT The author would like to thank the department o Electrical & Electronic Engineering (EEE) o Chittagong Univerity o Engineering and Technology (CUET), Chittagong-39, Bangladeh.. REFERENCES [] Devendra Kumar Shukla and Sudhanhu Tripathi, Thyritor Controlled Power or Induction Motor, International Journal o Innovative Reearch & Studie, vol., no. 7, July 3. [] Atul M.Gazare and Nitin R. Bhame, A Review on Speed Control Technique o Single Phae Induction