Peak Current Mode Control of Coupled Inductor based High Step-Up Gain Boost Converter

Abstract

High step-up gain Coupled Inductor Boost Converter (CIBC) discovers application in Distributed Generation System (DGS) to step-up voltage level of renewable energy sources. In DGS system, high step-up CIBC with a regulated output voltage and faster dynamic operation is required at various local loads. Transfer function of CIBC has one zero on Right Hand Plane (RHP). It is difficult to achieve high bandwidth when system has Non-Minimum Phase (NMP) characteristic. Peak Current Mode (PCM) control is the well-known technique to improve dynamic response in DC-DC converters. To design feedback controller and to analysis behaviour of CIBC, small signal model of CIBC is required. This paper presents small signal control-to-output voltage transfer function for PCM control of CIBC. Effect of artificial ramp is considered in derivation of this small signal model. A state space averaging method is used to derive small signal model. PI controller is designed using root locus technique. Time and frequency response of Voltage Mode Control (VMC) and PCM control of CIBC are compared. PCM control improves transient response and stability margin of CIBC for wide range of load variations. It also reduces effect of RHP zero. Simulation of CIBC using PCM control to get regulated output voltage is done in PSIM. Simulation results demonstrate that CIBC is able to get desire dynamic and steady state response of output voltage using PCM control under dynamic load conditions.