Design of Intelligent Based Battery Charger for a Pure Sine Wave Inverter

The purpose of this work is to design an intelligent battery charger for use with a pure sine wave inverter. It expresses a relatively new idea that is yet to break grounds in some parts of the world. It discusses four components which are inverter, battery, battery charger and artificial intelligence (which can be referred to as the controller). The controller serves as the central processor that processes the output of the charger and tells the whole system what to do about a particular problem. The major problems faced by the system were highlighted as well as the problem faced in charging a battery manually and automatically. The manual charging is a charging system that needs full monitoring in order to prevent overcharging and some other charging problems that is faced while charging. The automatic charging however has improved upon the demerits of the manual charging and has provided us with a safe and a lower level of supervision while charging. Various types of charging has been described in this research work and the best type of charging coupled with the best type of battery that is to work with a pure sine wave inverter has been described. Keyword: Artificial intelligence, battery, controller, inverter. INTRODUCTION The research work is based on the design of an intelligent battery charger for use with a pure sine wave inverter. The battery charger is such that detects the state of charge of the battery and switches from different modes till the battery attains its full charge state. The research work is very important because it has been discovered that the major problem with batteries used with inverters is that they deteriorate due to overcharging and undercharging because there is no mechanism in place to help in curtailing some extreme conditions. The battery charger will be controlled by a charge controller which prevent the battery from overcharging the battery. When the battery voltage rises to a preset maximum, where the battery is completely charged, the control automatically reduces or stops the charge as demonstrated in [1]. Chris Woodford [1], explain the state of health of the battery (SOH) as a figure of merit (FOM) of the condition of a battery (or a cell, or a battery pack), compared to its ideal conditions. The unit of SOH are percent points (100% = the battery conditions match the battery specifications). Typically, a battery’s SOH will be 100% at the time of manufacture and will gradually reduce as the battery is being used. Artificial intelligent systems however learn very quickly as compared to a programmed system. The research is based on designing a model of battery charger that can reason like a human being and take some crucial decisions on its own based on the input that it gets from the component that it is interacting with. Inverter though not a new technology have various types depending on their size and their nature of work. They are however subdivided into pure sine wave and modified sine wave as discussed later. The best type of inverter is the true or pure sine wave inverter, although expensive, but it provides a pure sine wave just like the alternating current produced as our shore power and has the ability to conveniently do well with some kind of loads that need a heavy starting. Pure sine waves are not widely used because of their cost of manufacture which is on the high side. The second type is the modified sine wave which tends to work like a pure sine wave inverter but not exactly like it. It does not however give the pure sine waveform but it produces a modified one which is gotten by modifying a square sine waveform. Background on smart battery There are several types of ‘smart’ batteries, each offering different complexities, performance and cost. The most basic JOURNAL OF ADVANCEMENT IN ENGINEERING AND TECHNOLOGY Journal homepage: http://scienceq.org/Journals/JAET.php Research Article Open Access


INTRODUCTION
The research work is based on the design of an intelligent battery charger for use with a pure sine wave inverter.The battery charger is such that detects the state of charge of the battery and switches from different modes till the battery attains its full charge state.The research work is very important because it has been discovered that the major problem with batteries used with inverters is that they deteriorate due to overcharging and undercharging because there is no mechanism in place to help in curtailing some extreme conditions.The battery charger will be controlled by a charge controller which prevent the battery from overcharging the battery.When the battery voltage rises to a preset maximum, where the battery is completely charged, the control automatically reduces or stops the charge as demonstrated in [1].
Chris Woodford [1], explain the state of health of the battery (SOH) as a figure of merit (FOM) of the condition of a battery (or a cell, or a battery pack), compared to its ideal conditions.The unit of SOH are percent points (100% = the battery conditions match the battery specifications).Typically, a battery's SOH will be 100% at the time of manufacture and will gradually reduce as the battery is being used.
Artificial intelligent systems however learn very quickly as compared to a programmed system.The research is based on designing a model of battery charger that can reason like a human being and take some crucial decisions on its own based on the input that it gets from the component that it is interacting with.
Inverter though not a new technology have various types depending on their size and their nature of work.They are however subdivided into pure sine wave and modified sine wave as discussed later.The best type of inverter is the true or pure sine wave inverter, although expensive, but it provides a pure sine wave just like the alternating current produced as our shore power and has the ability to conveniently do well with some kind of loads that need a heavy starting.Pure sine waves are not widely used because of their cost of manufacture which is on the high side.The second type is the modified sine wave which tends to work like a pure sine wave inverter but not exactly like it.It does not however give the pure sine waveform but it produces a modified one which is gotten by modifying a square sine waveform.

Background on smart battery
There are several types of 'smart' batteries, each offering different complexities, performance and cost.The most basic 'smart' battery may only contain a chip to identify its chemistry and tell the charger which charge algorithm to apply.Other batteries claim to be smart simply because they provide protection from overcharging, under-discharging and short-circuiting.In the eyes of the Smart Battery System (SBS) forum [2], these batteries cannot be called 'smart'.The SBS forum states that a 'smart' battery must be able to provide SoC indications [3].Benchmark was the first company to commercialize the concept of the battery fuel gauge technology.Early IC chips date back to 1990.Several manufacturers followed suit and produced 'smart' chips for batteries Any charging system that is devoid of proper charging procedure and that is not properly monitored is soon going to fail.The research work is however going to be a profitable one since the design is meant to actually stand on its own and also conduct a maintenance work on its own.It is on its way to acceptability by the general Nigerian populace.

Project description
The design has arisen from the evident of short lifespan of batteries used with inverters and also their archaic charging techniques which has made the charging system to be almost unreliable.It is also meant to provide a feedback system that is capable of providing the necessary interface needed in a charging setup.
All smart chargers are intended for unsupervised use, being foolproof to connect, spark proof and reverse-polarity protectedallowing charging to be a safe and convenient task.A smart charger can be left attached to a battery for an indefinite amount of time without risk of either the charger or battery overheating making them the perfect product for use on cars that are used infrequently, driven on regular short journeys or left standing for long periods of time e.g. over the winter.This is what this project describes.The project is aimed at presenting an intelligent charging system that meets all charging requirements and can work with any type of battery.The project is also aimed at designing a smart charger that can work under any condition and still produce a desired outcome.The battery charger can however be a stand-alone device or a built-in device, but for the purpose of this project we would be dealing with a stand-alone mechanism of charging.

Artificial intelligence
According to Luger and Stubblefield [4] artificial intelligence (AI) is the intelligence of machines and the branch of computer science that aims to create it.AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its chances of success.John McCarthy, who coined the term in 1956, also defines it as "the science and engineering of making intelligent machines".
The field was founded on the claim that a central property of humans, intelligence-the sapience of Homo sapiens-can be so precisely described that it can be simulated by a machine.This raises philosophical issues about the nature of the mind and the ethics of creating artificial beings, issues which have been addressed by myth, fiction and philosophy since antiquity.Artificial intelligence has been the subject of optimism, but has also suffered setbacks and, today, has become an essential part of the technology industry, providing the heavy lifting for many of the most difficult problems in computer science.

Applications of AI
Artificial intelligent is important to inverter systems because it does not just follow some set of rules, but it learns something and then integrates it into its memory.Inverter systems need intelligence to a large extent because the timing and other requirements needed in its switching application is a very important factor.

Inverters
According to [5], an Inverter converts the DC current from a battery to AC current.Some inverters convert to 110 volts, some to 240 volts AC, based on what we need.
Essentially, an Inverter performs two tasks: 1.It converts Direct Current to Alternating Current.

It acts as a step-up transformer by converting 12 volts to 240
volts.
There are two main types of Inverters; 1. Pure Sine Wave, 2. Modified Sine Wave.

Pure or True Sine Wave Inverters
A pure or true sine wave inverter converts the dc supply into a near perfect or pure sine wave, replicating the supply attained from a domestic ac power source such as a plug socket.The sine wave has very little harmonic distortion resulting in a very 'clean' supply and makes it ideal for running electronic systems such as computers, digital fax racks and other sensitive equipment without causing problems or noise.
Ideal for all applications, the pure sine wave inverter is a must for anyone needing to convert power from a dc source to a universally useable AC supply.Unfortunately they are very expensive compared to the modified alternative.The waves that emanate from a true sine wave inverter are more or less like a pure sine wave curve.

Modified (Quasi) Sine Wave Inverters
Modified sine wave inverters are much cheaper and somewhat rougher alternative to the pure Sine Wave Inverter.Instead of the output being a pure sine wave, the cheaper circuitry in the Modified Sine Wave Inverter outputs a rough sine wave.This means equipment with circuitry that relies on the smooth oscillation of a true sine wave, like dimmer switches, PC power supplies, variable speed motors and scientific equipment like oscilloscopes etc. may not work properly or as efficiently as they would otherwise.

Battery charger
Battery charger is a kind of electric devices used to put energy into a secondary cell or (rechargeable) battery by forcing an electric current through it as seen in [6].The charge current depends upon the technology and capacity of the battery which is being charged.For example, the current that should be applied to recharge a 12 V car battery will be very different from the current for a mobile phone battery.The battery charger includes a first charging circuit controlling input power to charge an external battery detachably mounted to the charger; A charger configured to charge batteries includes a housing, a plurality of battery storage chambers accommodating the batteries, the battery storage chambers being aligned in a horizontal direction such that depth directions of the battery storage chambers are parallel to each other.Internal secondary battery charged by the input power; a charge or discharge control circuit charging the internal battery by the input power and controlling a charge of the internal battery; and a control circuit controlling an operative state of the first charging circuit and the charge or discharge control circuit.The charger serves to charge the detachably mounted external battery both by the input power and by the internal battery.The charger is so structured that when the input power is not in a inputted state, the control circuit supplies the electric power from the internal battery to the charge or discharge control circuit into an operative state, where an operative state of the internal battery is controlled, thus discharging the internal battery to charge the external battery by the discharged electric power.
An intelligent battery charger can be seen in the fact that you may be able to detect when cells are fully charged.Then the process is stopped by closing the connection to the terminal.This can occur concurrently when the cells were added at the same time.But if you put them in different time frames, this means that each terminal stop at a time depending on the total amount you received.This automated ability to detect when all terminals are fully charged removes the fear of damage or overloading of power.
Finally, to demonstrate that automated intelligence battery charger comes with a screen for each terminal so that the owner can monitor the processes running within each cell in high security.This makes it possible to eliminate one of these when they are seen on the screen to be fully loaded for immediate use.
The battery puts out 12 volts DC current.As we know, home electrical appliances run on 240 volts AC.So we need to convert the 12 volts DC coming from the battery to 240 volts AC that our electrical devices require.
An Inverter converts 12 volts DC to 240 volts AC.The advantages of this type of power backup system are numerous compared to a conventional diesel generator.
i.No noise.
ii.No fuel required.
iii.Practically maintenance free once you get it up and running.
iv. Can be upgraded and downgraded easily.
An Inverter is connected to the battery, which converts the 12 volts DC current, to 240 volts AC.A power strip can then be connected to the inverter, and electrical appliances connected to the strip.During a blackout, this system will be able to run most electrical appliances, with the exception of high power appliances like refrigerators, air conditioners, etc.

Battery
According to David L. and Thomas B [6], there are two main classes of batteries: (1) Crank, and (

Charge rate
Charge rate is often denoted as C or C-rate and signifies a charge or discharge rate equal to the capacity of a battery in one hour.For a 1.6Ah battery, C = 1.6A.A charge rate of C/2 = 0.8A would need two hours, and a charge rate of 2C = 3.2A would need 30 minutes to fully charge the battery from an empty state, if supported by the battery.This also assumes that the battery is 100% efficient at absorbing the charge, this can be seen in Duracell NiMH charging methods [8].
The standard automotive battery chargers that is mostly used is call (linear) constant voltage chargers.In simple terms what this means is that as the battery is charging, the voltage slowly rises, and as the voltage rises the current (amps) that the charger is putting into the battery starts to drop off, and keeps falling until the battery voltage is up around 14 volts or so, at this point the amps going in has now dropped off to almost nothing and the battery is deemed to be 'charged' but they are NOT really fully charged, and also this process can take a very long time because of the constantly reducing current input.On the other hand these chargers when left connected to a battery for too long can, and often do damage the battery.Smart multi stage chargers may cost a bit more, but they do fully charge a battery at a faster rate, and at the same time they do it safely, giving the battery what it needs, when it needs it.
Smart multi stage chargers start first with the 'boost' stage, in this stage the charger puts in as much current as the charger is capable of and for as long as it can safely do so.In this stage it operates as a constant current charger, so if it's a 10A charger it will put in a constant 10 amps until the battery reaches a voltage set point that is normally about 14.4-14.7v.At this time the battery is about 75-85% charged.Now the next stage begins, the 'Adsorption' stage, and the charger now turns into a constant voltage charger, it now holds the voltage at the set point, say 14.4 volts.The only way it can achieve this is that it must back off the current, otherwise the voltage would just keep climbing higher and higher, so it must vary the current to hold the battery at the 14.4 volts as the battery adsorbs the last of the required current that it needs to become fully charged.After some time the amount of current flowing to keep the battery at the set point is so small that the chargers smart processor circuit says to itself, "hey, I've been holding this battery at the required voltage until the amps have dropped off to almost nothing, this battery has stopped accepting any real current now, so it must be fully charged!" the charger now convinced that the battery has finished charging and is fully charged, goes into the next stage, the 'Float or maintenance' stage, this is where it backs the current off even further so that the battery voltage drops to around 13.5-13.8v,and now holds it there by varying the current again, the lower voltage is below the electrolytes gassing point and can be left on charge like this indefinitely, and if power is being drawn from the battery the charger just ramps up the current output to match the draw.

Research design
The design is subdivided into four different units which are; i.The charger ii.The battery iii.The inverter iv.The controller It is from these units that we start the design work.Essentially, the charger and the controller are usually connected together.The battery is dependent on the charger as whatever the state of the battery is, the charger can know it and hence route the status to the controller that serves as the processor.The inverter is a stand-alone unit on its own and it just needs feeds only when AC power is off (when it switches to inverting mode) or when it is to indicate that the battery is in its charging mode.
The relationship between time to full charge, battery capacity and charge rate current is given below: Since the design takes the control system algorithm, we would have a block diagram which has a feedback as shown in the figure 1 below.Let the input signal be R(t), the output signal be F(t), and the controller be Q(t).
Since we know that for the system to operate in a closed circuit, the difference between the input and the output must be zero, which can be written mathematically as: The above equation is the perfect condition for a closed system From the above block diagram we can observe that some parameters are shown immediately after the charger unit, they are the parameters to be measured (inputs).The output is the state of charge (SoC), state of health (SoH), etc. the mathematical relationship between the parameters are what the feedback element will process.

The controller
This serves as the processor and it contains sensors and actuators.The sensors serve as the input device while the actuators serve as the output device.The sensors sense the incoming instruction and then pass it to the controller which in turn passes it to the actuators which decides which action to take.
There are sixteen different outputs and inputs in the diagram above.The sensors serve as the input device while the actuators serve as the output device.The actuators here, process the outcome of whatever the input is.The controller here is the major design as we do not know its values.

Pictorial view of the research design
An animated pictorial view of the supposed input and output of the design in order to aid understanding of what the project is about is shown below.Macromedia flash was used for this pictorial view.

CONCLUSION AND RECOMMENDATION
This research work has shown that artificial intelligence based battery charger would meet the current power problems in a country like Nigeria and even proffer a better solution to charging problems associated with Inverter systems.This work is different from a programmable work in the sense that it does not just work like a robot; it has an inherent ability to learn new conditions and integrate it into its complex system.The trend of artificial intelligence based chargers will definitely provide people with an intelligent charging and system as a whole and it will help in reducing the volume of work that is still being done manually.
The controller is the most important aspect of the project as it serves as the central processing unit, as it can be seen in a desktop computer

RECOMMENDATION
It would be recommended that the field of artificial intelligence be effectively tapped into as there are still a lot to learn in this field.It will be very interesting to see how this field can provide us more technological breakthrough that we all desire.More research work should be done on artificial intelligence as it is the core of all engineering discipline.Also artificial intelligence would also be very useful in the renewable energy applications like solar systems, wind generation systems, biomass and others.

Figure 1 :
Figure 1: Block Diagram of an Intelligent based battery charger Inverter

Figure 2 :
Figure 2: Controller pin connection 2) Deep cycle.Crank batteries are used in cars and motorcycles.When a car is ignited (cranked up), it requires a temporary high current.This zaps the battery.The car immediately commences charging the battery back-up while the car is running.Deep cycle batteries are used in RV's, boats, etc. Deep cycle batteries are more suitable for slow discharge, and for situations where the battery is charged or discharged very frequently.A crank car battery would die very quickly if treated this way.
For best results, it is advised to not allow Crank batteries to be discharged below 20%, i.e. the battery should always have a charge of 80% or more.Deep cycle batteries should not be discharged beyond 50%.