Design and Performance Comparison of PI and PID Controllers For Half Bridge DC-DC Converter

Transcription

1 International Journal of Advanced Reearch in Electrical and Electronic Engineering Volume: 2 Iue: 1 08-Mar-2014,ISSN_NO: Deign and Performance Comparion of PI and PID Controller For Half Bridge DC-DC Converter R. Ilayaraman 1, L.Raguraman 2, J.Rajakumar 3 PG Scholar, Power Sytem Engineering, Chandy College of Engineering,India 1 Aitant Profeor, Dept of EEE, Chandy College of Engineering,India 2 Aitant Profeor, Dept of EEE, Chandy College Of Engineering, India 3 ilayaramanmmk@gmail.com, raguraman.5138@gmail.com, rajakumarj13@gmail.com ABSTRACT -Proportional Integral Derivative (PID) controller i the mot widely ued controller in the indutrie becaue of it implicity and robutne. Different type of tuning are propoed for PID controller[1]- [4]. Thi paper propoe a new technology, which utilize the duty cycle ignal to improve the light load efficiency with imple implementation. In thi paper Ziegler-Nichol tuned PID cheme i developed for DC-DC converter where large load change are expected or the need for fat repone time[9]. The Ziegler-Nichol rule developed in thi paper i ued for tuning dicrete PID controller to obtain it parameter with a minimum computing complexity and i applied to Half Bridge DC-DC converter to improve it performance. The tranient repone and ettling time of the converter i improved and it i compared with the Ziegler-Nichol baed PI controller. Keyword - Variable parameter PID, Ziegler-Nichol method,pi Controller. 1, INTRODUCTION The witch-mode dc dc converter are power electronic ytem that convert one level of electrical voltage into another level by witching action. Thee converter are very popular becaue of their high efficiency and maller ize, and therefore are ued extenively in peronal computer, communication, medical electronic and adapter of conumer electronic device to provide different level of dc voltage. The widepread ue of witching dc dc converter in many electronic ytem make a neceity for many electronic ytem deign engineer to deign and develop efficient and reliable upplie according to demand. Switching converter are in general, time-variant, nonlinear dynamic ytem[13]. The non-linearity arie primarily due to witching, power device, and paive component, uch a inductor, and capacitor. A a reult, the conventional linear control technique can t be directly applied to analyze. To deign the feedback compenation uing linear control technique, a dynamic model of the witching converter i needed. The dynamic ytem hould model the low frequency behavior of the ytem, but hould neglect the inignificant behavior at and beyond the witching frequency. Therefore modeling proce hould involve the approximation to neglect the high frequency phenomena. The Z-N tuning proce hould atify two important requirement. Firt it hould not affect converter operation under nominal condition and econd it hould be baed on a imple and robut algorithm whoe complexity hould not ignificantly increae the ilicon area of the IC controller[11]. A compreive tudy ISRJournal and Publication Page 1

2 International Journal of Advanced Reearch in Electrical and Electronic Engineering Volume: 2 Iue: 1 08-Mar-2014,ISSN_NO: ha been done and cheme i preented for Ziegler-Nichol tuned PI & PID controller to improve the tranient repone under et-point change and load diturbance. 2, PID CONTROLLER AND BUCK CONVERTER A general body of a PID control ytem i hown in Fig.1, where it can be een that in a PID controller, the error ignal e(t) i ued to generate the proportional, integral, and derivative action, with the reulting ignal weighted and ummed to form the control ignal u(t) applied to the plant model.. Figure.1 A typical PID control ytem 2.1 Different PID Controller Tuning Method Depite there are many deign method for PID controller, the mot widely ued deign method in the literature are Ziegler-Nichol rule, Chien-Hrone-Rewick PID tuning algorithm, Cohen-Coon tuning algorithm, Wang-Juang-Chan tuning formulae[7]. The Ziegler-Nichol[3] deign method which wa preented in mid-20th century i the mot popular method ued in proce control to determine the parameter of a PID controller. One of the important pecialtie of thi ytem guarantee the tabilitie. PID control conit of three type of control, Proportional, Integral and Derivative control[1]. Proportional Control: The proportional controller output ue a proportion of the ytem error to control the ytem. However, thi introduce an offet error into the ytem. P term = K P x Error (1) Integral Control: The integral controller output i proportional to the amount of time there i an error preent in the ytem. The integral action remove the offet introduced by the proportional control but introduce a phae lag into the ytem. I term = K I x ʃ Error dt (2) Derivative Control: The derivative controller output i proportional to the rate of change of the error. Derivative control i ued to reduce/eliminate overhoot and introduce a phae lead action that remove the phae lag introduced by the integral action. D term = K D x d(error)/dt (3) 2.2 Buck Converter ISRJournal and Publication Page 2

3 International Journal of Advanced Reearch in Electrical and Electronic Engineering Volume: 2 Iue: 1 08-Mar-2014,ISSN_NO: The buck or tep down converter regulate the average DC output voltage at a level lower than the input or ource voltage. Thi i accomplihed through controlled witching where the DC input voltage i turned on and off periodically, reulting in a lower average output voltage. The buck converter i commonly ued in regulated DC power upplie like thoe in computer and intrumentation. The buck converter i alo ued to provide a variable DC voltage to the armature of a DC motor for variable peed drive application Figure.2 Block diagram of buck converter 3, PROPOSED METHOD The demand for the high efficiency DC-DC converter i increae dramatically, epecially for ue in battery operated device uch a cellular phone and laptop computer. The witched mode power upply i called a the high efficiency power upply and buck converter i one of them therefore it i of great importance to reearch on buck converter. good performance. The output voltage i controlled by varying the duty cycle. Figure.3 Block diagram of a propoed ytem Proportional Integral Derivative (PID) controller i the mot widely ued controller in the indutrie becaue of it implicity and robutne. Different type of tuning are propoed for PID controller. Thi propoed ytem propoe a new technology, which utilize the duty cycle ignal to improve the light load efficiency with imple implementation. In thi propoed ytem Ziegler-Nichol tuned PID cheme i developed for DC-DC converter where large load change are expected or the need for fat repone time.the tranient repone and ettling time of the converter i improved. 4, DESIGN OF PID AND PI CONTROLLER 4.1 Ziegler-Nichol method-1 ISRJournal and Publication Page 3

4 International Journal of Advanced Reearch in Electrical and Electronic Engineering Volume: 2 Iue: 1 08-Mar-2014,ISSN_NO: Controller K p T i T d P T/t d PI 0.9T/t d 3.33t d PID 1.2T/t d 2t d.5t d Table.1 Formula For Z-N Method 1 PID Controller: Tranfer function for PID Controller i K p = 12 K i = 10.4*e3 K d = 3.42*e-3. ) (4) PI Controller: The tranfer function for PI controller i K p = 9 K i = 4.7*e-3. (5) 4.2 Ziegler-Nichol method-2 Controller K p K i K d P T/t d PI T/t d t d /0.3 PID 1.2T/t d t d /0.5.5t d Table 2. Formula for Z-N method-2 PID Controller: PI Controller : K p = 12 K i = 1.14*e-3 K d = 2.85*e-4. Kp = 9. K i = 1.9 * e-3. 5, SIMULATION RESULTS ISRJournal and Publication Page 4

5 International Journal of Advanced Reearch in Electrical and Electronic Engineering Volume: 2 Iue: 1 08-Mar-2014,ISSN_NO: Figure.4 Cloed Loop Simulation Circuit for Z-N PID 1 and Z-N PI 1 Figure.5 Simulation Waveform of Output Voltage for ZN -PID 1 and ZN-PI 1 6,SIMULATION ANALYSIS 6.1 Ziegler Nichol Method 1 and Method 2 Parameter PI PID Maximum 3.02v 2.95v peak overhoot (Mp) Rie time (tr) 1.04 * e * e- 3 Peaktime (tp) 2.2 * e * e-3 Delay time (td) ISRJournal and Publication 8.56 * e * e-4 Parameter PI PID Maximum 1.03v 0.9v peak overhoot (Mp) Rie time (tr) 1.42 * e * e-3 Peaktime (tp) * e * e- 3 Delay time (td) 8.65 * e * e-3 Page 5

6 International Journal of Advanced Reearch in Electrical and Electronic Engineering Volume: 2 Iue: 1 08-Mar-2014,ISSN_NO: Settling time (t) Steady tate error (e) 3.33 m 3.1 m 12.2 % 7.1 % Settling time (t) Steady tate error (e) 3.48 m 3.4 m 15.4 % 12.6 % Table.3 Simulation analyi uing Ziegler-Nichol method 1 and method 2 VII. CONCLUSION In pite of the fact that controller deigned by the Ziegler-Nichol rule give a good performance. In thi paper, the control technique applicable for a buck converter i propoed and the analyi of it operating principle wa dicued. In thi paper, a Ziegler-Nichol tuned PID cheme ha been preented for DC-DC converter It i concluded that with the ue of voltage feedback loop contant output voltage i obtained.the propoed cheme continuouly adjut the controller gain through Ziegler-Nichol rule defined on the intantaneou proce tate. It can be eaily applied to an exiting controller. The effectivene of the propoed controller ha been teted through imulation experiment on Half Bridge DC-DC converter. The performance of the converter i compared with ZN tune PI controller i applied with initial parameter. The Ziegler-Nichol tuned PID ha hown conitently enhanced performance both in tranient and teady tate condition. In the propoed cheme tranient repone and ettling time of the converter ha been improved. REFERENCES [1] K.J. Atrom, T. Hagglund, Advanced PID Control, ISA-The Intrumentation, Sytem, and Automation Society, [2] B. Armtrong, D. Neevel, T. Kuik, New reult in NPID control: tracking, integral control, friction compenation and experimental reult, IEEE Tran. Control Syt. Technol., vol. 9(2), pp , [3] B. Armtrong, B.A. Wade, Nonlinear PID control with partial tate knowledge: damping without derivative, Int. J. Robotic Reearch, vol. 19(8), pp , [4] W.H. Chen, D.J. Balance, P.J. Gawthrop, J.J. Gribble, J. O Reilly, Nonlinear PID predictive controller, IEE Proc. Control Theory Appl., vol. 146 (6), pp , [5] J.Q. Han, Nonlinear PID controller, Acta Automatica Sinica, vol. 20(4), pp , ISRJournal and Publication Page 6

7 Powered by TCPDF ( International Journal of Advanced Reearch in Electrical and Electronic Engineering Volume: 2 Iue: 1 08-Mar-2014,ISSN_NO: [6] W. Wang, J.T. Zhang, T.Y. Chai, A urvey of advanced PID parameter tuning method, Acta Automatica Sinica, vol. 26(3), pp , [7] J.J. Gu, Y.J. Zhang, D.M. Gao, Application of Nonlinear PID Controller in Main Steam Temperature Control, Aia Pacific Power and Energy Engineering Conference, pp. 1-5, Wuhan, Chine, [8] O. Aydogdu, M. Korkmaz, A Simple Approach to Deign of Variable Parameter Nonlinear PID Controller, International Conference on Electrical Engineering and Application, pp , Chennai, India, [9] Stefanutti, Mattavelli,Saggini.S, and M. Ghioni, Auto-Tuning of Digitally controlled DC-DC converter baed on relay feedback, IEEE Tran. On Power Electronic, vol.22, No.1, pp ,2007. [10] Middlebrook.R.D, Small-ignal modeling of pule-width modulated witched-mode power converter, Proc. IEEE, vol. 76, no. 4, pp ,1988. [11] Hang C.C,Åtröm K.J, and Ho.W.K, Refinement of Ziegler-Nichol tuning formula, IEE Proceeding- D,Vol.138,No.2,pp. ISRJournal and Publication Page 7