A variable structure, model reference adaptive control (VS-MRAC) devoted to cancel interferences without the requirement of an auxiliary input is proposed. This method is an improved alternative to the strategies recently proposed in the control theory literature.Peer ReviewedPostprint (published version

Bertran Albertí, Eduardo

Montoro López, Gabriel

Electronics Letters

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References 0 0  0 5  1 0  15 2 0  VE E ,v 1112121 Fig. 2 Gummel plot of pseudomorphic AllnP/lnP HBT with emitter area of 40x40& 50 I I 45 - 40 - 35 - 0 2  4 6 8 1 0 1 2 1 4  FE,” m Fig. 3 Common-emitter characteristics of pseudomorphic AlInP/JnP HBT with emitter area of 40x40pm2 IB step = 250pA Gummel plot is shown in Fig. 2. Ideality factors for base and col- lector current were 1.7 and 1.3, respectively. We estimate that the 15% AI composition results in a bandgap difference between emit- ter and base of 87 meV (after accounting for strain effects). The common-emitter IN characteristics are shown in Fig. 3. The com- mon-emitter breakdown voltage BVcEo was of the order of 10 V, while the common-base breakdown voltage BVcao was 13V. BV,,, is not much larger than BV,,,, and both values are some- what smaller than estimated values for ideal InP p-n junctions. The breakdown voltages can most likely be attributed to surface breakdown as opposed to junction breakdown. Nonetheless this is a significant improvement over devices with an InGaAs base and collector. Summary: We have presented novel HBTs with pseudomorphic wide-bandgap AIInP emitters and InP base and collector regions. The devices permit the use of InP collectors in a way that avoids a conduction-band barrier between base and collector. These devices are candidates for high speed and/or high breakdown HBT appli- cations. 0 IEE 1995 Electronics Letters Online No: 19950084 Y.M. Hsin, M.C. Ho, X.B. Mei, H.H. Liao, T.P. Chin, C.W. Tu and P.M. Asbeck (Department of Electric and Computer Engineering, University of California. San Diego, LA Jolla, CA 92093-0407, USA) 23 Nocember 1994 NOTTENBURG, R.N., CHEN, Y.K., PANISH, M.B., HAMM, R., and HUMPHREY, D.A.: ‘High-current-gain submicrometer InGaAdInP heterostmcture bipolar transistors’, IEEE Electron. Device Lett., 1988, 9, pp. 524526 CHEN, Y.K., NOTTENBURG, R.N., PANISH, M.B., HAMM, R. ,  and HUMPHREY, D.A.: ‘Subpicosecond InP/InGaAs heterostructure bipolar transistors’, IEEE Electron. Device Lett., 1989, 10, pp. 267- 269 CHAW, H.F., and BEAM, E.A.: ‘High-speed InP/InGaAs heterojunction bipolar transistors’, IEEE Elecfron. Device Left..  1993, 14, (8), pp. 388-390 SONG, J.I.,  HONG, B.w.P., PALMSIROM, c.J., VAN DER GAAG, B P . ,  and CHOUGH, K.B.: ‘Ultra-high-speed lnP/lnGaAs heterojunction bipolar transistors’, IEEE Electron. Device Letf.,  1994, 3, p. 94 ‘InPflnGaAs double heterojunction bipolar transistors grown by metalorganic vapor phase epitaxy with sulfur delta doping in the collector region’, Appl. Phys. Lptt., 1990, 57, (26), pp. 2841-2843 MONTGOMERY, R.K., YADMSH, R.D., and TEMKIN, H.: ‘A 144GHz InPnnGaAs composite collector heterostructure bipolar transistor’. IEDM 92-75, 1992, pp. 75-78 considerations in InP/lnGaAs single and double-heterostructure bipolar transistors’, IEEE Trans., 1993, ED-40, (I) ,  pp. 2-8 ISHIBASHI, I.: ‘Fabrication and characterization of high- performance InPiInGaAs double-heterojunction bipolar transistors’, JEEE Trans., 1994, ED41, (8), pp. 1319-1326 LIN,K.C. ,  HSIN,Y.M., CHANG.C.Y., and CHANG,E.Y.: ‘A pseudomorphic GalnPiInP MESFET with improved device performance’, JEEE Trans., 1993, E M ,  (12), pp. 2361-2362 TOKUMITSU, E., DENTAL A.G., IOYNER, C.H., and CHANDRASEKHAR, S.: FEYGENSON, A., HAMM, R.A., SMITH, P.R., PINTO, M.R., CHAW,, PAVLIDIS, D., HU, I . ,  and TOMIUWA, K.: ‘Breakdown-speed KURISHIMA, K., NAKAJIMA, H., KOBAYASHI, I., MATSUOKA, Y., and Adaptive VS-MRAC for disturbance cancellation E. Bertran and G. Montoro Lopez rndexing terms: Model reference aduprive control system, Interference suppression A variable structure, model reference adaptive control (VS- MRAC) devoted to cancel interferences without the requirement of an auxiliary input is proposed. This method is an improved alternative to the strategies recently proposed in the wntrol theory literature. Introduction: In the general structure of a conventional noise can- celler [I], the reference signal, which must be correlated with the additive noise, can be obtained from the measurement of the inter- ference at some point of the system. When that is not possible due either to the impossibility of observing or measuring the interfer- ence noise, the conventional canceller structure is not useful. Non-adaptive VS-MRAC controllers can cancel interferences or unmodelled dynamics with only the requirement of the prior infor- mation concerning the interference bounds [2]. These methods show a fast response with zero error, but present chattering prob- lems due to the switching functions that appear in the control law. Adaptive VS-MRAC controllers are used when the interference bound is unknown: the bound is obtained adaptively [3, 41. Recently [4], a new method has been proposed that uses an inte- gral law to generate the adaptive bound, with a zero output track- ing error, in spite of chattering phenomena. We propose a proportional-integral based law to generate the adaptive bound. This method reduces chattering and high fre- quency harmonics, assuring that the error tends to zero. VS-MRAC canceller: The system (ARMAX) describing the evolu- tion of the error is represented by the state equations [5] 142 ELECTRONICS LElTERS 79th January 1995 Vol. 37 No. 2 - -- - _. __ - S ( t )  = As( t )  + b v ( t )  E ( t )  = cTz ( t )  = yp(t)  - y,(t) v ( t )  = u( t )  - $J(t)a + i f ( t )  u( t )  = J ( t ) k ( t )  +Ui(t) (1) where i,(t) is the interference to cancel, referred to the input. The plant output is y,(f) ,  y,(t) the model output, and u(t) the control signal. The transfer function H(s) between e(t) and v( t )  is H ( s )  = cT(s1  - A ) - ' b  (2) and must be an SPR (strictly positive real function) function [SI. Therefore, defining the vector $(t)  = k( t )  - a, the error equations can be rewritten as i ( t )  = Az(t)  + b v ( t )  E ( t )  = cTr ( t )  u ( t )  = W T ( t ) ( k ( t )  - a )  + u z ( t )  + i f ( t )  = VT( t )@( t )  + u, ( t ,  + i f ( t )  (3) The k(t) vector is selected according to an integral law: it is a clas- sical adaptive algorithm if the plant is disturbance free. The uxt) signal, devoted to cancel the interference, is chosen as in [2, 61 (4) L( t )  = $ ( t )  = -Rp( t )E( t )  u,(t)  = -sgn(E) max(lif1) where max(li,l) is a bound for li,l. The Lyapunov function candi- date is L = sT( t )Pz( t )  + $'(t)R-'@(t) ( 5 )  where P is a positive definite matrix, and R is a positive definite diagonal matrix. The time derivative of L is given by i = -zT(t)Qz(t)  + 2~(t)(-sgn(~)max(l i , / )  + i f ( t ) )  5 0 i 5 -xT(t)Qz(t)  lim Z ~ ( T ) & T ( T ) ~ T  5 L(0) 1'- I' (6) where Q is a positive definite matrix [SI. Hence L is hounded and converges to a finite value. Moreover, x( t )  is continuous due to its derivative being bounded. Therefore, it follows from the Barbalat lemma that x(t )  + 0 when t 3 - [SI. Adaptive VS-MRAC canceller: If the bound of i/ct) is unknown then it can be obtained adaptively [3, 41. We propose a new solu- tion: the adaptive generation of the unknown bound with an inte- gral-proportional based law. The u l t )  signal is u,(t) = -sgn(E)M(t) (7) with fi, > 0. We can consider a zero initial condition for M ( f ) .  A Lyapunov function candidate is L = rT( t )Pz( t )  The time derivative of L is given by L = -zT(t)&s(t)  + ~ ~ ( t ) ( - s g n ( ~ )  max(lif1) i, 5 -rT(t)&r(t)  + i f ( t ) )  - 2P2Ii(t)l2 i 0 (9) as in eqn. 6, it follows that x(f) + 0 and e ( f )  + 0 when t + m. The choice of p2 = 0, leads to an integral law, like in [4]. Simulution resulfs: The plant, reference model and error equations are defined by where e( f )  = y,,(t) - ym(f). Therefore u ( f )  and H(s) are 44 = h'l(t)Y,(t) + Kz(t)uJt)  + u,(t)  (11) H ( s )  = a,>O a,>O s + b ,  H(s) is SPR. The k, parameters are generated from (12) kl(t) = -71e(t)y,(t) & ( t )  = - -^i2E(t)Uc(t)  where y, > 0. The signal u i f )  is given hy uz( t )  = -sgn(E)M(t) V S - M R A C  : M ( t )  = M = rnax(lzf1) adaptive  V S - M R A C  : M ( t )  = I E ( T ) ~ ~ T  + pZ/E(t) l  (13) Jd' The previous systems have been simulated with the parameters a, = 1 ,  6,  = I ,  a, = 0.9, b, = 1.2, yl = y2 = 1. The command signal u,(t) is a square wave and i ( f )  is a strong interference defined by i(r) = sin(0.5f) + sin(t) + sin(2t) + sin(3t). The SIMNON graphic results (see Figs. 1 and 2) are: a Proposed adapfive VS-MRAC fiI = 1, p2 = 50 b Adupfive VS-MRAC fiI = I (integral law) c VS-MRAC: max(li,l) = 6 20 1 10 0 -1 0 -20 I a 300 31 0 320 330 1 0  0 -1 0 -20 I b 300 310 32 0 33 0 20 0 -1 0 c 300 310 320 330 rn Fig. 1 Steady-stafe control signal u,(f) j f--y-L-r-., -1 2 1 a O  20 LO 60 8 0  100 0 A .  L r 20 40 60 80 100 b1 C O  20 40 60 80 100 Fig. 2 Plant and model responses ELECTRONICS LETTERS 19th January 1995 Vol. 31 No. 2 --- -__ - 143 Conclusions: The simulation results show the good behaviour of the proposed adaptive system, even for strong interferences in the same spectral band of the plant. In spite of the use of the signum function, the control signal u,(t) shows a lower chattering content (high frequencies) than the equivalent signal proposed in previous works. Apart from hardware considerations, this aspect has a sig- nificant importance in telecommunication applications. The method has been studied with other types of perturbations, unmodelled dynamics and nonlineanties in the plant, with similar results as above. 0 IEE 1995 Electronics Letters Online No: 19950088 21 October 1994 E. Bertran and G. Montoro L6pez (Department of Signal Theory and Communications, Universitat Politecnica de Catalunya, PO Box 30.002. 08080 Barcelona, Spain) References COWAN, c.F.w., and GRANT. P M. (Eds.): ‘Adaptive filters’ (Prentice- Hall, 1985) HSU, L.: ‘Variable structure model-reference adaptive control (VS- MRAC) using only input and output measurements: Part 11’. Proc. 27th IEEE Conf. Decision and Control, December 1988, pp. 2396- 2401 NARENDRA, K.s., and BOSKOVIC, J.D.: ‘A combined direct, indirect and variable structure method for robust adaptive control’. Proc. Automatic Control Conf., May 1990, pp. 543-548 FENG, G.: ‘New robust model reference adaptive control algorithm’, IEE Proc. Control Theory Appl., May 1994, 141, pp. 177-180 NARENDRA, K.s., and ANNASWAMY, A.M.: ‘Stable adaptive systems’ (Prentice-Hall, 1989) BERTRAN. E., and MONTORO. G.: ‘Application of hyperstability theory to interference cancelling’. Proc. 7th Mediterranean Electrotechnical Conf., April 1994, Vol. 2, pp. 679-682 ERRATA LING, C.H., AH, L.K., and YEOW, Y.T.: ‘Observation of current spikes in thin oxide MOS capacitor’, Electron. Lett., 1994, 30, (24), pp. 2077-2079 Printers corrections In the subcaption to Fig. I ,  ‘815’ should read ‘815000’ In the subcaption to Fig. 2, ‘30mW should read ‘30mV’ In the line below Fig. 2, ‘scaned‘ should read ‘scanned‘ In the caption to Fig. 3, ‘Cuurent’ should read ‘Current’ Authors’ correction In the subcaptions to Fig. 3, the first line should read ‘Hold time [SI at V, = 2V:’ Editor’s corrections In the subcaptions to Fig. 3, ‘a’ to ‘h’ should read ‘(i)’ to ‘(viii)’ In line 11 on p. 2079, and on the right-hand side of Fig. 4, the minus sign should read ‘=’ SHIEH, J.-L., CHYI, J.-I. ,  LIN, R.-J., LIN, R.-M., and PAN, 1.-w.: ‘Band offsets of In,,,Gao ,&s/In,.,,~.,,As heterojunction grown on GaAs sub- strate’ Electron. Lett.,  1994, 30, (25), pp. 2172-2173 Authors’ correction In Table I ,  the entries for ‘Charge neutrality level’ should read ‘0.39’ and ‘0.68’ respectivelyl9th January 1995 ESTIMATION OF LENGTH FOR ELECTRONICS LE77€RS Title Indexing terms Abstract Authors Text 1 column cm per 80 characters 1.5 column cm (this includes adjacent space) 1 column cm per 165 characters 1 column cm, plus 1 column cm for each address 1 column cm per 165 characters (it is easiest to estimate the number of characters, including spaces, per line and the number of lines per page); add 0.5 or even 1 column cm for each equation or line in a matrix unless it is well displayed; counts of words or even characters made by word processors are not reliable for this purpose References 1 column cm each Tables 1 to 2 column cm for the title, 0.4 column an for each line, including blanks; wide tables will be reshaped by editorial staff and the estimate adjusted accordingly I column cm for the main caption, 0.33 column cm per line for subcaptions, including keys which would be moved from the graphics These are usually reduced to single column width (8.6 cm) at constant ratio of height to width; if the Figure is illegible at this reduction, the editing staff will redraw it and the height will be recalculated accordingly Figure captions Figures VERSION 4.0 144 ELECTRONICS LETTERS 19th January 1995 Vol. 31 No. 2 --- - __ ~ 

Adaptive us-mrac for disturbance cancellation

A variable structure, model reference adaptive control (VS-MRAC) devoted to cancel interferences without the requirement of an auxiliary input is proposed. This method is an improved alternative to the strategies recently proposed in the control theory literature.Peer Reviewe

Adaptive us-mrac for disturbance cancellation

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