International Conference on Innovations in Power and Advanced Computing Technologies [i-PACT2017] 1 BBBC based Optimization of PI Controller Parameters for Buck Converter Akhilesh K. Gupta Bandi Mallikarjuna Reddy Dept. of Electrical Engineering, MNNIT Dept. of Electrical Engineering, MNNIT Utter Pradesh, Allahabad, INDIA Utter Pradesh, Allahabad, INDIA akhileshgupta08@ gmail.com ree1505@mnnit.ac.in Deepak Kumar Paulson Samuel Dept. of Electrical Engineering, MNNIT Dept. of Electrical Engineering, MNNIT Utter Pradesh, Allahabad, INDIA Utter Pradesh, Allahabad, INDIA deepak_kumar@mnnit.ac.in paul@mnnit.ac.in Abstract— the most widely used controllers in industries are PI or PID controllers. The major concern with designing of such controllers is the determination of controller parameters. An intelligent method is discussed in this paper to determine the controller parameter to control the dynamic performance of buck converter by optimizing these parameters with the big bang big crunch (BBBC) algorithm. Initially, the mathematical modeling is developed and thereafter the weighted numerical values of overshoot, peak time, rise time and settling time are summed to make a fitness function which is to be minimize for the better dynamic response. The performance of BBBC-PI controller is analyzed by settling time, rise time and overshoot of the output response. The disturbance rejection ability of optimized PI controller is verified by three cases such as step change in input voltage, output voltage and output load resistance. The closed loop operation of buck converter is simulated and verified at the MATLAB/Simulink platform. Keywords– BBBC, Buck Converter, Fitness function, PI, Optimization Algorithm I. INTRODUCTION ower electronics converters are gaining adamant popularity in the field of generation and transmission of electrical power. Conversion of one level of electrical energy to the other level of electrical energy is possible by these power converters in the field of SMPC. The energy is first transmitted via electronic switches to energy storage devices and afterward these devices act as a source to transmit the stored energy into the load. MOSFETs and IGBTs are most popular choice for the controlled switch application whereas diodes act as an uncontrolled switch. Inductors and capacitors are used as energy storage elements. This process of energy transfer results in an output voltage that is pertaining to the input voltage by the duty ratios of the switches. The buck converter [1-2] is a ubiquitous DC- DC converter that efficiently converts a high voltage to a low voltage efficiently. Efficient power condition is very important to enhance the battery life, and to reduce heat generated during the application. The buck converter can be used in lots of specific applications like microprocessor and embedded systems. It offers the required local voltage from a higher voltage bus that is common to several converters in the system. The buck converter itself comprises of one active controlled switch and an uncontrolled switch along with the filters elements. This great simplicity allows for cost operative high efficient power distribution throughout the application. The buck converter has the filter inductor on the output side, which provides a smooth continuous output current waveform to the load. This could be reflected a qualitative profit but requires special considerations for huge load transients. Buck converter provides the regulated dc supply from unregulated dc supply for various application which needs regulated dc supply. A number of modern control techniques such as optimal control [3] linear control [4], nonlinear control [5], sliding mode control [6] and hybrid controllers [7] etc. have been proposed to improve the dynamic performance of power converters. Along with above explained techniques, state space control [8] and LQR control [9] are also used as output voltage control method for dc/dc converters. Although, several methods are available for closed loop operation of converter but PID and PI error control technique is still most popular and powerful technique because of its simplicity in hardware as well as software implementation. The main challenge with the PID or PI controller implementation is tuning of their parameters. These parameters are main constraints for the effectiveness and robust transient performance of the controller. Ziegler-Nichols [10] method is applied to obtain the closed loop behavior of controller. The complex mathematical model requirement and high overshoot limits the use of this method. Since last few years, a numerical approach for finding optimum solution under certain constraints, called optimization techniques are applied to find the parameters of PI or PID controllers to improve the performance and robustness behavior of controller. Genetic Algorithm [11-12], Particle Swarm Optimization [13-14] and Bacterial Foraging Optimization (BFO) [15-16] and Artificial Bee Colony (ABC) [17] are successfully applied by the several researchers for closed loop operation of buck converter. In this article, the P 978-1-5090-5682-8 /17/$31.00 ©2017 IEEE