Digital Simulation of FM-ZCS-Quasi Resonant Converter Fed DD Servo Drive Using Matlab Simulink

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1 SERBIAN JOURNAL OF ELECTRICAL ENGINEERING Vol. 6, No. 2, Novembe 2009, UDK: : Digital Simulation of FM-ZCS-Quasi Resonant Convete Fed DD Sevo Dive Using Matlab Simulink Kattamui Naasimha Rao 1, Vyza Chinna Veea Reddy 2 Abstact: This pape deals with digital simulation of FM-ZCS-quasi esonant convete fed DC sevo dive using Matlab Simulink. Quasi Resonant Convete (QRC) is fast eplacing conventional PWM convetes in high fequency opeation. The salient featue of QRC is that the switching devices can be eithe switched on at zeo voltage o switched off at zeo cuent, so that switching losses ae zeo ideally. Switching stesses ae low, volumes ae low and powe density is high. This popety impats high efficiency and high powe density to the convetes. The output of QRC is egulated by vaying the switching fequency of the convete. Hence it is called Fequency modulated Zeo cuent/zeo voltage switching quasi esonant convete. The pesent wok deals with simulation of DC Sevo moto fed fom ZCS-QRC using Matlab. Simulation esults show that the ZCS-QRC s have low total hamonic distotion. The ZCS-QRC opeating in half wave and full wave modes ae simulated successfully. Keywods: Quasi esonant convete (QRC), Zeo cuent switching (ZCS), Pulse width modulation (PWM). 1 Intoduction Thyistoised powe contolles ae now widely used in the industy. Conventional contolles involving magnetic amplifies, otating amplifies, mecuy ac amplifies, esistance contolles etc., have been eplaced by thyistoised powe contolles. Contolles of DC dives and AC dives widely use thyistoised powe contolles in olling mills, textile mills, pape mills, canes, taction vehicles and mine windes etc., Some othe aeas whee thyistoised powe contolles employed ae uninteuptible and standby powe supplies fo citical loads, static powe compensation, special powe supplies fo ai caft and space 1 Depatment of Electical Engineeing, BMS College of Engineeing, P.O. Box No.: 1908, Bull Temple Road, Basavanagudi, Bangaloe , Kanataka, India; kn_kn@yahoo.com 2 Depatment of Electical and Electonic Engineeing, Si Venkateswaa Univesity, Tiupati , Andha Padesh, India; veeaeddy_vc@yahoo.com 227

2 K.N. Rao, V.C.V. Reddy applications, tansfome tap changes and static connecto fo industial powe systems, powe convesion at the teminals of HVDC tansmission system, HV supplies fo electonic pecipitatos and X-ay geneatos. 2 Quasi Resonant Convete The fundamental depatue fom the conventional foced tun off appoach is the zeo cuent switching (ZCS) technique, poposed by F C Y Lee et al (1987). Replacing the switches as powe switches (MOSFET, GTO ) in the PWM convetes by esonant switches gives ise to a new family of convetes, namely Quasi Resonant Convetes (QRC). This new family of convetes can be viewed as a hybid between PWM convetes and esonant convetes. They utilize the pinciple of inductive o capacitive enegy stoage and powe tansfe in a simila fashion as PWM convetes. The cicuit topologies also esemble those of PWM convetes. Howeve an LC tank cicuit is always pesent nea the powe switch and is used not only to shape the cuent wavefoms though the powe switch and the voltage wavefom acoss the device. It can also stoe and tansfe enegy fom input to output in a manne simila to the conventional esonant convetes. The two types of ZCS-QRC convetes ae: (a) half wave; (b) full wave as shown in Figs. 1(a) and 1(b). (a) 2 ZCS Popeties (b) Fig. 1 (a) Half wave ZCS-QRC; (b) Full wave ZCS-QRC. The following ae the popeties of zeo cuent switching: 228

3 Digital Simulation of FM-ZCS-Quasi Resonant Convete Fed DD Sevo Dive The switch tun-on and tun-off occus at zeo cuent, which significantly educes the switching losses. 2. Sudden cuent changes in the switch ae avoided in ZCS. 3. The d i /dt value is small, the stesses ae educed and hence EMI is educed. 4. The peak cuent [ I0 + Vdc / Z0] Conducted by switch must be moe than twice as high as the maximum of the load cuent I 0 and Z 0 is the chaacteistic impedance 5. The output voltage can be vaied by vaying the switching fequency. 6. The intenal capacitances of the switch ae dischaged duing tun on in ZCS, which can poduce significant switching loss at high switching fequency. (a) (b) Fig. 2 (a) Powe cicuit of Half wave FM-ZCS-QRC fed sevo dive; (b) Wavefoms of Half wave FM-ZCS-QRC. 229

4 K.N. Rao, V.C.V. Reddy A conventional Fequency modulated-zeo cuent switching-quasi esonant convete cicuit and its opeating wavefoms ae shown in Figs. 2(a) and 2(b) espectively. The sinusoidal cuent wavefom in the case of zeo cuent esonant switch/the sinusoidal voltage wavefom in the case of Zeo voltage esonant switch, geneated by the wavefom shaping LC esonant elements ceates a zeo cuent/voltage condition fo the switch to tun-off/tun-on without switching stesses and losses, which ae given by vaious mathematical equations fom (1) to (9). A switching cycle can be divided into fou stages. The associated equivalent cicuits fo these fou stages ae shown in modes of opeation fo half wave and full wave cicuits espectively. Assume initially fee wheel diode ( D fw ) caies the output cuent ( I 0 ) and esonant capacito voltage ( V C ) is clamped at zeo and switch S is off. At the beginning of the switching cycle t = t 0, S is switched on. 3 Modes of Opeation 1. MODE 1: When S is tuned on at t = t0, the input cuent ( i L ) ises linealy and is govened by the state equation V = L(d il / d t). The duation of the mode, td1 = ( t1 t0) can be solved with bounday conditions which can be expessed by equations (1) il ( t0) = 0 and il ( t1) = I0 (1) t = t t = L I / V. d Fig. 3 Equivalent cicuit fo mode Mode 2: At time t = t1, when the input cuent ises to the level of I 0, 230 D fw is tuned off and the amount of cuent ( il () t I0 ) is now chaging C, which can be given by the state equations (2) to (5):

5 Digital Simulation of FM-ZCS-Quasi Resonant Convete Fed DD Sevo Dive... with the initial conditions VC ( t 1) = 0 and il ( t1) = I0. dvc C = il I0, d t d il L = V VC(), t d t, (2) V il () t = I0 + Z sin ωt, If a half wave esonant switch is used, switch S will be natually commutated at time when the esonating input cuent il ( t ) educes to zeo. On the othe hand, if a full wave esonant switch is used, cuent i () t will continue to oscillate and enegy is fed back to souce, V though though fw 0 D fw L. Cuent D again oscillate to zeo. The duation of this stage t 2 = ( t2 t1) can be solved by setting i ( t 2 ) = 0. L d Thus, Fig. 4 Equivalent cicuit fo Mode 2 opeation. t d 2 α = ω, (3) whee π α 3 π / 2 fo half wave mode; 3 π/ 2 α 2π fo full wave mode. 0 0 α=, (4) acsin Z I V At time t 2, V C can be solved using: V ( t ) = V(1 cos α ). (5) C d 2 231

6 K.N. Rao, V.C.V. Reddy 3. Mode 3: This stage begins at t 2, when the cuent though inducto L is zeo. At t = t2, S is tuned off. The Capacito C dischages though the load to supply constant load cuent. Hence V C deceases linealy and educes to zeo at t 3. The state equation fo this mode is given by the equations (6) to (8) dvc C = I0. (6) d t The duation of this stage td 3 = ( t3 t2) (7) can be solved with the initial condition. V ( t ) = V(1 cos α ). (8) C 2 Fig. 5 Equivalent cicuit fo Mode 3 opeation. 4. Mode 4: This stage stats with the conduction of feewheeling diode and the amatue cuent feewheels though D fw fo a peiod t d 4 until S is tuned on again. The duation of this stage is td4 = TS td1 td2 td3, (9) whee T S is the peiod of a switching cycle. Fig. 6 Equivalent cicuit fo Mode 4 opeation. 232

7 Digital Simulation of FM-ZCS-Quasi Resonant Convete Fed DD Sevo Dive... 4 Simulation Results (a) (b) (c) Fig. 7 (a) Half wave ZCS QRC with RLE Load; (b) Cuent though inducto L ; (c) Voltage acoss capacito 233 C.

8 K.N. Rao, V.C.V. Reddy The undestanding of the opeation of a powe electonic cicuit equies a clea knowledge of the tansient behavio of cuent and voltage wavefom fo each and evey cicuit element at evey instant of time. Fo the easy undestanding of the tansient esponse compute aided simulation softwae s wee used. The FM-ZCS-QRC has been simulated using MATLAB simulink softwae. Fo simulation pupose the values chosen ae L = 168 μ H, C = 2.2 μ F, V = 75 V, R a = 5 Ω, L a = 30 mh, and E b = 35 V. Half wave ZCS QRC with RLE load is shown in the Fig. 7a. The cuent though the inducto is shown in the Fig. 7b. Voltage acoss the capacito is shown in the Fig. 7c. Full wave ZCS QRC with RLE load is shown in the Fig. 8a. The cuent though the inducto and Voltage acoss the capacito is shown in the Fig. 8b. Full wave ZCS QRC with moto load is shown in the Fig. 6a. The cuent though the inducto is shown in the Fig. 9b. Voltage acoss the capacito is shown in the Fig. 9c. Speed esponse cuve is shown in Fig. 9d. The speed inceases and settles at 100 ad/s. (a) Fig. 8 (a) Full wave QRC with RLE load; (b) Cuent though inducto L and voltage acoss capacito 234 (b) C.

9 Digital Simulation of FM-ZCS-Quasi Resonant Convete Fed DD Sevo Dive... (a) (b) (c) 235

10 K.N. Rao, V.C.V. Reddy (d) Fig. 9 (a) Full wave QRC with moto load.; (b) Cuent though inducto L ; (c) Voltage acoss capacito C ; (d) oto speed in ad/sec. 5 Conclusion The FM-ZCS-QRC was simulated using MATLAB SIMULINK softwae. By vitue of this modeling appoach, design of quasi esonant convetes can be ealized efficiently and effectively by using soft switching techniques. Switching stesses get educed since voltage and cuent wavefoms have lesse slope. Powe density is inceased since the volume is educed. The appoach of maintaining zeo cuent switching condition is also identified fom the simulated wavefoms, ie. wheneve cuent is zeo, switch S tuns on and off. Simulation wavefoms coincide with theoetical wavefoms. QRC fed Sevo dive is a viable altenative to the DC dive since it has less losses and high powe density. The speed of the sevo moto can be vaied by vaying the off time of the QRC. 6 Refeences [1] S.R. Reddy, C. Chellamuthu: Pefomance of a DC Moto Fed fom Seies and Paallel Quasi-esonant Convetes, Intenational Jounal of Powe and Enegy Systems, Vol. 17, No. 3, 1997, pp [2] L. Bo-Tao, L. Yim-Shu: Novel Actively-clamped Zeo Cuent Switching Quasi-esonant Convetes, IEEE Intenational Symposium on Cicuits and Systems, Hong Kong, 9-12 June 1997, Vol. 2, pp [3] L.K. Wong, F.H. Leung, P.K.S. Tam: A Simple Lage Signal non Linea Modeling Appoach fo Fast Simulation of Zeo Cuent Switching Quasi-esonant Convetes, IEEE Tansactions on Powe Electonics, Vol. 12, No. 3, May 1997, pp

11 Digital Simulation of FM-ZCS-Quasi Resonant Convete Fed DD Sevo Dive... [4] G.H. Cho, J.G. Cho: Cyclic Quasi-esonant Convete: a New Goup of Resonant Convetes Suitable fo Highe Pefomance DC/DC and AC/AC Convesion Applications, poc IEEE IECON, 1990, pp [5] B.T. Lin, G. Lin, S.S. Oiu: A New Goup of Quasi-esonant Convetes, South Ohina Univesity Poc, Vol. 23, No. 8, 1995, pp [6] K.H. Liu, O. Ramesh, F.C.Y. Lee: Quasi-esonant Convetes Topology and Chaacteistics, IEEE Tansactions on Powe electonics, Vol. PE-2, No. 1, Jan. 1987, pp [7] R.B. Ridely, W.A. Tabisz, F.C.Y. Lee, V. Vopeian: Multi Loop Contol of Quasi-esonant Convetes, IEEE Tansactions on Powe Electonics, Vol. 6, No. 1, Jan. 1991, pp [8] G. Ume, C. Chellamuthu: A Novel Closed Loop Opeated Soft Switched DC to DC Convete fo Electical Vehicles, IEEE Powe Engineeing Society Winte Meeting 2000, Vol. 1, pp [9] K.N. Rao, V.C.V. Reddy: Implementation of FM-ZCS-Quasi Resonant Convete fed DC sevo dive, Jounal of Theoetical and Applied Infomation Technology, Vol. 5, No. 4, Apil 2009, pp [10] K.N. Rao, V.C.V. Reddy: Digital Simulation of FM-ZCS-Quasi Resonant Convete Fed DC Sevo Dive using Matlab Simulink, IESPEEE09, SRM Univesity, Chennai, India. [11] P.C. Sen: Pinicples of Electic Machines and Powe Electonics, 2nd edition, Wiley Publications, Dec [12] S. Aulselvi, C. Subhashini, G. Ume: A New Push-pull Zeo Voltage Switching Quasiesonant Convete: Topology, Analysis and Expeimentation, IEEE INDICON 2005, Dec. 2005, pp [13] S. Aulselvi, G, Uma, B. Kalaanjani: Design and Simulation of Model based Contolles fo Quasi Resonant Convetes using Neual Netwoks, India Intenational Confeence on Powe Electonics 2006, IICPE 2006, Chennai, India, Dec. 2006, pp

IMPLEMENTATION OF FM-ZCS-QUASI RESONANT CONVERTER FED DC SERVO DRIVE

IMPLEMENTATION OF FM-ZCS-QUASI RESONANT CONVERTER FED DC SERVO DRIVE 1 K. NARASIMHA RAO, 2 DR V.C. VEERA REDDY 1 Research Scholar,Department of Electrictrical Engg,S V University, Tirupati, India 2 Professor,