Implementation of Hybrid Optimization technique for optimal tuning of a Cascaded controller for DC DC converters

Abstract

Cuk Converter and Zeta converter are focused on this work. Both the converters newlineconsist of energy storage elements, i.e, two inductors, and two capacitors. Cuk newlineconverter produces inverted output whereas the Zeta converter produces a non-inverted output. Proportional Integral (PI) control is designed to control the output voltage of the converter. The controller parameters are tuned using the classical method such as Zeigler Nichol s tuning, Particle Swarm Optimization (PSO), and Particle Swarm Optimization Gravitational Search Algorithm (PSOGSA). The steady-state response of the converter was analyzed with servo response and regulatory response. PI Controller is a linear controller that gives the desired closed-loop response in the linear region of operation. This PI controller will give a different response at different operating regions for a non-linear system when subjected to disturbances. Cuk and Zeta converters exhibit non-linearity due to the presence of energy storage elements which cause the system to become unstable with the same PI parameters. Hence there arises a necessity for a non-linear controller. Sliding Mode Control(SMC), otherwise called variable structure systems(VSS) whose structure changes intentionally during the time by following a preset control law. The structure changes due to the action of controlled switches and diodes but there is chattering in the output. Hence PI-SMC controller is used in shaping the input current in the converter. Moreover, to enhance the performance of the system, an evolutionary algorithm such as PSO was used to tune the PI parameters. This technique when applied converges very slowly and this can be minimized by using hybrid optimization techniques by combining two or more algorithms. In this proposed work, a PSOGSA based optimization is presented to tune the PI controller in the voltage control loop and the SMC controller was used to reduce the error in the inner current control loop. Better performance and Setpoint trackingare explored in PSOGS