Flyback Converter Analysis

Abstract – Hybrid electric vehicle is a need of the today’s world because of the fact that it is pollution free and has more fuels efficiency. Flyback converter plays important role in hybrid electric vehicles because it is an isolated DC-DC boost converter. In the proposed work simulation of flyback converter has been done in the SIMULINK tool of MATLAB and voltage and current waveforms are obtained .The results of simulations matches the theoretical calculations and which led to the development of hardware model of Flyback converter.
Keywords-Hybrid Electric Vehicles, Flyback Converter, buck-boost converter, PMOSFET.
I. INTRODUCTION
In the modern world lots of attention has been given in hybrid electric vehicles. Many companies like Toyota,
We have chosen the PMOSFET for the design of hybrid electric vehicles because its switching is smooth and it has positive temperature of coefficient so there is no second breakdown as in case of Power MOSFET. Moreover paralleling of Power MOSFET is very easy [6], [7].
Flyback converter is an isolated buck-boost converter. It has one very big advantage over dc-dc converter because it is difficult to obtain large input–output voltage ratio with a dc-dc converter, because D may not reach a very small values. For the same reason it is difficult to obtain output voltage that is adjustable in large range. Because of this fact it increases the input voltage of voltage-source inverter and reduces the size of batteries [8], [9],
The paper has been organized as follows. An elaboration of various topologies of hybrid electric vehicles is given in section II. Third section deals with theoretical aspects of flyback converter.Simulation of flyback converter and forward converter have been discussed in section IV. Fifth section is the overall
Series hybrid Parallel hybrid Series- parallel hybrid Complex hybrid
. Figures 1,2,3,4 are the block diagrams of various types of hybrid electric vehicles (HEV) in which the bidirectional link is Electrical, the unidirectional link is hydraulic and the mechanical link (clutches and gears) is also bidirectional. The main feature of the series hybrid is to couple the ICE with the generator which is used for electric propulsion, where in the parallel hybrid to propel the wheels we couple both the ICE and electric motor with the transmission via the same drive shaft. The series parallel hybrid is used features of both the series and parallel hybrids. Among four complex HEV has more versatile feature.
A. Series hybrid electric vehicles
The series hybrid has very simple construction. The mechanical output that we are getting from ICE is converted into electricity using a generator. The converted electricity is either used to charges the battery or it can directly used to propel the wheels via the same electric motor and mechanical transmission. Due to the absence of clutches throughout the mechanical link, it has the certain advantage of flexibility locating the ICE-generator