Simulation, Design and Implementation of dsPIC based 1 kW Multi Phase Interleaved Bi-directional DC-DC Converter

Abstract

A Bi-directional DC-DC converter has its applications in many places, such as in hybrid vehicles, solar inverters, power supplies for microprocessors etc. A high voltage supply using a single converter is not preferred as it leads to high ripple in output voltage and current. This increases the value of inductor and filter capacitor. The output ripple can be reduced by increasing the switching frequency but it also increases the switching losses. Thus to improve this, multiphase interleaving is used in bidirectional DC-DC converters. A bidirectional DC-DC converter can be alternately operated as a step down converter in one direction of energy flow and as step up converter in reverse direction of energy flow, i.e. flow from source to load and load to source respectively.

The idea of paralleling converters with even distribution of switching instants is called multiphase interleaved. The interleaved converters are connected in parallel. They are operated at the same switching frequency with their switching waveforms displaced in phase over a switching period. The switching frequency seen by the converter thus becomes N*fs, where N is number of converters connected in parallel. This reduces the size of filter while switching frequency remains fs, also the ripple frequency becomes high there by giving smooth output current.

The proposed work done is to develop a general purpose 1 kW dsPIC based bi-directional DC-DC converter. The open loop and closed loop simulation is done in simulation tool and accordingly prototype is developed and tested.