CHAPTER 1 : INTRODUCTION
1.1 INTRODUCTION:
As we find that many devices used in modern days are based on the power electronics, and power devices are having wide range of the applications. So in some way or other power devices may be used. In many applications there is requirement of converting fixed supply of D.C into variable D.C voltage for example electric automobiles, in traction system, in solar photovoltaic systems, in fuel cells, etc. DC-DC converter may be used.
Advantage of using DC-DC converter is that they have good voltage regulation, fast dynamic response, and has higher efficiency. Also they can be used in regenerative braking in DC motor for giving energy back to the supply. Energy saving is possible due to this. Also they are used in power levels ranging from small batteries to large high voltage power transmission systems. These converter can widely used for electrical vehicle as a dc input source in future developments. ex: electric cars, motors etc.
1.2 OBJECTIVE OF THE PROJECT:
The overall size, efficiency and cost are the main advantage of power converter devices compared to other devices. The ultimate aim of our project is to give an optimize power resources to run electrical vehicles in day to day life. The electrical input helps in saving fuel cost, Power management and also the electrical driven vehicles are more efficient, accurate & stable then the other fuel operated vehicles. Our DC electrical based input helps to increase the usage of electrical power based vehicles in futures and day to day life in various other matters also.
1.3 PROBLEM SOLVING:
Here in our project we have mainly focused on boost converter by the use of the optimization techniques. So first we have made the open loop control of the system in the MATLAB software and saw the results. We found that results were not proper because we had given input as 17v and output we obtained was 40v instead of 34v. So we found that open loop results had unsatisfactory dynamic response and poor voltage regulation. So the novel techniques were proposed using ziegler nichols and genetic algorithm. So this techniques exhibit good voltage regulation and satisfactory dynamic response under close loop control, Also, this technique exhibit less time for the change in the response variable than other conventional methods.
Literature survey
Sr No. 1
Title DC-DC Converter For Electric Vehicle.
Author Dakshina M. Bellur, Marian K . Kazimierczuk
Year 2007
Type of paper Electrical Insulation Conference and Electrical Manufacturing Expo
Objective A DC-DC converter supplies conventional low-power, low-voltage loads, The need for high power bidirectional DC- DC converters in future electric vehicles has led to the development of many new topologies of DC-DC converters.
Proposed technique • Several DC-DC converters such as isolated, non isolated, half-bridge, full-bridge, unidirectional and bidirectional topologies, and their applications in electric vehicles are presented.
Result • More used of electrical vehicles
• Improve efficiency and saving of fuels
Literature survey
Sr No. 2
Title A power dense DC-DC converter for a small electric vehicle.
Author F.J. Bryan, A.J. Forsyth
Year 2012
Type of paper Journal (IEEE Power Electronics, Machines and Drives)
Objective A power dense DC-DC converter is required to interface a super capacitor energy buffer with a higher voltage traction drive in a small electric vehicle application
Proposed technique • A converter design and component selection process is described for a bidirectional, 18 kW, dual interleaved boost converter with interphase transformer.
Parameter Power density of 6.5 kW/kg and 7.9 kW, 18 kw interphase transformer.
Result • Improved Power Quality
• Better interference mitigation to electronic devices
CHAPTER 2:
ANALYSIS, DESIGN AND IMPLEMENTATION STRATAGY
2.1 EMPATHY MAPPING CANVAS:
There are different types of the stakeholders that can use this product are like people, engineers, research engineers, industrial instrumentation engineers, etc. Also we have discussed about the user and designing features. Happy and sad story is built up where we went for the activities and there may be different types of the user for this type of the product.
Figure 1: Empathy Mapping Canvas
2.2. IDEATION CANVAS:
Now For building up the project we went to different types of labs, malls, schools, colleges, etc; and for getting a idea about the project, we went to the electrical/electronics labs, mechanical labs, classrooms, research labs, board rooms and computer labs.
For the activities we performed experiments in the labs and had the conversations with the staffs and lab assistant. Also we had seen videos in the YouTube and had Google search.
Possible solutions can be by the use of the open and close loop boost converter and by using the optimization techniques. This can be achieved by the use of controller and setting the values of the controller gain.
Figure 2: Ideation canvas
2.3 PRODUCT DEVELOPMENT CANVAS:
In this canvas we have built the idea about the progress of the project that is to done with some of the modifications in the existing model. In this work we discuss about the purpose, product experience, product features, customer revalidations, components, product functions, people, and some redesign which are done in the existing technology with conventional converter.
Figure 3: Product development canvas
2.4 AEIOU SUMMARY:
In this canvas we have discussed about the activities that are performed in the places which we went. Also after we have feel the environment in that places where we went. After the environment we discussed interactions among the people where we carried out the activities. Also in that place we saw the objects that were kept in that place and last there were user who used that product and user who performed that activity.
Figure 4: AEIOU summary
Chapter 3
BOOST CONVERTER IMPLEMENTATION
3.1 WHAT IS A BOOST CONVERTER?
Power for the boost converter can come from any suitable DC sources, such as DC generators, batteries, solar panels and rectifiers. The method that changes one DC voltage to a different DC voltage is called DC to DC conversion.
“Boost converter is a DC to DC converter with an output voltage greater than the source voltage. It is sometimes called a step-up converter since it “steps up” the source voltage.” The main DC to DC converters were developed in the early 1960s when semiconductor switches were available.
3.2 BLOCK DAIGRAM FOR BOOST CONVERTER:
Fig 5: BLOCK DIAGRAM OF BOOST CONVERTER
The voltage source provides the input DC voltage to the switch control, and also to the magnetic field storage element. The block which contains switch control directs the action of the switching element, whereas the output rectifier and filter deliver an acceptable DC voltage to the output.
3.3 APPLICATION:
Battery powered systems often stack cells in series to obtain higher voltage. However, sufficient heaping of cells is not possible in many high voltage applications due to insufficient space. Boost converters can increase the voltage and reduce the cell numbers.
Two battery-powered applications that use boost converters are hybrid electric vehicles (HEV) and lighting systems.
Battery power systems often stack cells in series to achieve higher voltage. However, sufficient stacking of cells is not possible in many high voltage applications due to lack of space. Boost converters can increase the voltage and reduce the number of cells. Two battery powered applications that use boost converters are used in hybrid electric vehicles (HEV) and lighting systems.
3.4 BOOST CONVERTER CIRCUIT:
In a boost converter, the output voltage is greater than the input voltage – hence the name boost”. A boost converter using a power MOSFET is shown below.
The function of boost converter can be divided into two modes, Mode 1 and Mode 2.
Fig.5(a) Circuit diagram of Boost Converter.
The circuits for the two modes of operation are shown below
:
Fig. (a) On State (Mode -1) Fig (b). Off State (Mode-2)
Mode 1:- It begins when transistor M1 is switched on at time t=0. The input current rises and flows through inductor L and transistor M1. As shown in figure 3.4.2 (a)
Mode 2:- t begins when transistor M1 is switched off at time t=t1. The input current now flows through L, C, load, and diode Dm. The inductor current falls until the next cycle. The energy stored in inductor L flows through the load. As shown in figure 3.4.2 (b)
The waveforms for the voltages and currents are shown below:
Figure 5(c): Waveforms
3.5 WORKING OF BOOST CONVERTER:
The key principle that drives the boost converter is the tendency of an inductor to resist changes in current by creating and destroying a magnetic field. In a boost converter, the output voltage is always higher than the input voltage.
(a) MODE 1 (ON STATE):-
When the switch is closed, current flows through the inductor in clockwise direction and the inductor stores some energy by generating a magnetic field. Polarity of the left side of the inductor is positive.
In the On-state, the switch is closed, resulting in an increase in the inductor current.
During on time 𝑇𝑜𝑛inductor current rises from 𝐼1 to 𝐼2 so,
𝐸𝑑𝑐=𝐿Δ𝐼/𝑇𝑜𝑛… (2)
𝑇𝑜𝑛=𝐿Δ𝐼/𝐸𝑑𝑐
If the switch is cycled fast enough, the inductor will not discharge fully in between charging stages, and the load will always see a voltage greater than that of the input source alone when the switch is opened. Also while the switch is opened, the capacitor in parallel with the load is charged to this combined voltage. When the switch is then closed and the right hand side is shorted out from the left hand side, the capacitor is therefore able to provide the voltage and energy to the load. During this time, the blocking diode prevents the capacitor from discharging through the switch. The switch must of course be opened again fast enough to prevent the capacitor from discharging too much.
The input current is the same as the inductor current as can be seen in figure 3.4.3. So it is not discontinuous as in the buck converter and the requirements on the input filter are relaxed compared to a buck converter.
(b) MODE 2 (OFF STATE):-
When the switch is opened, current will be reduced as the impedance is higher. The magnetic field previously created will be destroyed to maintain the current towards the load. Thus the polarity will be reversed (means left side of inductor will be negative now). As a result, two sources will be in series causing a higher voltage to charge the capacitor through the diode D.
In the Off-state, the switch is open and the only path offered to inductor current is through the fly back diode D, the capacitor C and the load R. This result in transferring the energy accumulated during the On-state into the capacitor.
During off time 𝑇𝑜𝑓𝑓inductor current falls from 𝐼2 to 𝐼1 so,
𝐸𝑜 − 𝐸𝑑𝑐 =𝐿Δ𝐼/𝑇𝑜𝑓𝑓… (1)
𝑇𝑜𝑓𝑓=𝐿Δ𝐼/(𝐸𝑜−𝐸𝑑𝑐)
Chapter 4
SIMULATIONS, RESULTS AND DISCUSSION
4.1 MATLAB SIMULATION OF BOOST CONVERTER
The MATLAB simulation of boost converter is as given below:
Figure 6: MATLAB Simulation of Boost Converter
Figure 7: Voltage across Inductor
Figure 8: Output Voltage
CHAPTER 5: CONCLUSION
Enhanced fuel consumption has been a growing concern among many individuals along with strengthened exhaust gas regulations. As such, electric vehicles that include at least one electrically driven motor have begun to be manufactured as an alternative to the traditional fuel combustion engine. Such electric vehicles, which are also called an environmentally-friendly vehicles, include fuel cell vehicles, hybrid electric vehicles, plug-in electric vehicles, and pure electric vehicles, which generates driving torque by using electric power system with a high voltage and a large current. Such an electric vehicle typically includes a motor to generate a driving torque, an inverter to control driving of the motor, The DC-DC boost converter is very much applicable for the use of electrical vehicle and for future technology and can further develop.