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Multilevel inverters have gained significant attention in recent years due to their ability to improve power quality, reduce total harmonic distortion (THD), and enhance efficiency in high-power applications.
to extract the maximum available power at any time and feed the extracted power into the grid. The inverters used in IBRs are generally designed to follow the grid volt-ages and inject current into the existing voltage. Therefore, they are known as grid following inverters (GFLIs).
In the islanded mode, one of the inverters, or a couple of them, should function as volt-age and/or frequency regulator(s) to form a local power grid. The concept of grid forming inverters (GFMIs) originated from this particular need.
IBRs that operate in the grid supporting mode are known as grid-supporting inverters (GSIs). Almost all the large-scale IBRs work as GSIs, and small-scale IBRs, typically below 5 MW, operate as GFDIs. The fundamental difference in grid interaction of GFMIs come from the way active and reactive power delivery to the grid is controlled.
Multilevel inverters are gaining significant traction in high-power, medium-voltage applications due to their distinct advantages over conventional two-level inverters. These inverters offer improved power quality, reduced harmonic distortion, lower voltage stress on switching devices, and higher efficiency.
For renewable energy sources (like solar systems, and wind turbine systems), inverters have a prominent role that is converting renewable energy into AC power and feeding AC power to the grid. What are the applications and uses of Inverters? An inverter is mostly used in uninterrupted power supplies (UPS).
The above applications cover the importance and uses of inverters in different domestic, commercial, and industrial applications. Thus, it performs several roles with multiple functions. Also, in advanced technologies such as smart grid systems, Vehicle to Home (V2H), and Vehicle to Grid (V2G), the inverter is very essential equipment.
The working principle of high voltage inverter is to control the speed of motor by changing the frequency of alternating current (AC), MICNO high voltage inverter adopts advanced power electronic technology and control algorithm to convert the input AC power into DC power, and then through the internal high-frequency PWM (Pulse Width Modulation) technology, convert the DC power into frequency-adjustable and voltage-adjustable AC power output.
The main function of the inverter is to convert the DC power to AC power by using the power electronics like the IGBT and MOSFET. Traditionally, many inverter systems will be implemented by the analog components. As the development of the digital processors, more and more low cost and high performance micro-controllers had got into the market.
Among the various inverter systems, there are two different types. The first type is the voltage output type, which outputs AC voltage as a voltage source. For example, the inverter in the UPS system is a typical voltage-type inverter. The other type is the current type, which outputs AC current in a specified power factor.
To produce a sine wave output, high-frequency inverters are used. These inverters use the pulse-width modification method: switching currents at high frequency, and for variable periods of time. For example, very narrow (short) pulses simulate a low voltage situation, and wide (long pulses) simulate high voltage.
Solar inverters produce solar energy input, then feed that solar energy to the grid. So the grid-tie technology and some of the protection are key points when designing a solar inverter system. This document describes the implementation of the inverter kit that used as a DC-AC part of the High Voltage Solar Inverter DC-AC Kit.
The available inverter models are now very efficient (over 95% power conversion efficiency), reliable, and economical. On the utility scale, the main challenges are related to system configuration in order to achieve safe operation and to reduce conversion losses to a minimum. Figure 11.1.
The kit has a nominal input of 400-V DC, and its output is 600 W, which can be fed to the grid. Many fields use this inverter, such as motor control, UPS, and solar inverter systems. The main function of the inverter is to convert the DC power to AC power by using the power electronics like the IGBT and MOSFET.
Basically, a capacitor consists of two parallel conductive plates separated by insulating material. Due to this insulation between the conductive plates, the charge/current cannot flow between the plates and is retained at the plates. The plates may be of different shapes like rectangle, square, circular, and can be made into. The image below is showing a simple circuit to show how capacitor charging and discharging takes place in a circuit. As the changeover switch moves. As we know that when a voltage source is connected to conductor it gets charged say by a value Q. And since the charge is proportional to the voltage. Capacitors are used in almost every field of electronics, and play a very significant role in power circuits as well. Depending on the application we may. The standard unit of capacitance is Farad, named after scientist Michael Faraday. 1 Farad=1 coulomb/volt Farad is a very large unit, in practice, we generally use smaller units like Nano farads, Pico farads, Micro farads, etc.
[PDF Version]A capacitor, or “ cap ” for short, is an electronic device that stores electrical energy in the form of electric charges on two conductive surfaces that are insulated from one another by a dielectric material. A capacitor is a common and widely used electrical component that serves various functions and applications.
In electronics, we use capacitors for filters, oscillators, and tuned circuits, and for these applications mostly ceramic capacitors due to their superior dielectric properties. Capacitors can also be used as timing devices as the charging and discharging time can be predetermined using RC time constant.
There's almost no circuit which doesn't have a capacitor on it, and along with resistors and inductors, they are the basic passive components that we use in electronics. What is Capacitor? A capacitor is a device capable of storing energy in a form of an electric charge.
Each plate is connected to an external terminal, enabling the capacitor to be integrated into an electrical circuit. The standard symbol used to represent a capacitor in circuit diagrams consists of two parallel lines representing the plates of the capacitor, separated by a gap to signify the dielectric material.
This is a simplified view of how a capacitor is constructed. At its most basic, a capacitor consists of two conducting plates made of materials like aluminium or tantalum, positioned parallel to each other with a small space between them.
A capacitor also has the following basic electrical characteristics: Store and filter electrical currents. Block direct current (DC) from flowing through it. Allow alternating current (AC) to flow through it. How Does a Capacitor Work? How Does a Capacitor Work?
Battery energy storage system (BESS) has been applied extensively to provide grid services such as frequency regulation, voltage support, energy arbitrage, etc. Advanced control and optimization algorithms are i. ••Battery energy storage systems provide multifarious applications. Battery energy storage system (BESS)BESS grid serviceBESS allocation and integrationUsage pattern and duty profile analysisFrequency regul. AcronymsABESS Aggregated battery energy storage systemaFRR Automatic frequency restoration reserveAGC Automatic generation contr. Battery energy storage systems (BESSs) have become increasingly crucial in the modern power system due to temporal imbalances between electricity supply and demand. The po. 2.1. Literature survey: observation and motivationThere is a substantial number of works on BESS grid services, whereas the trend of research and dev.
[PDF Version]Therefore, choosing energy stor-age to cascade utilize retired power batteries not only provides a large-scale and low-cost source of batteries for energy storage but also holds important significance for establishing an electricity market system that adapts to the new power system.
Based on an estimated residual capacity of 70–80% when retired from new energy vehicle power modules, potential application areas for cascade utilization include power sources for electric bicycles, tour buses, and fixed energy storage scenarios that meet energy density requirements.
To maximize the extent of cascade utilization by the energy storage station under favor-able profit compensation conditions owing to the increased peol, the battery manufacturer appropriately reduces the usage price of the cascaded batteries sold to the storage station.
The cascade utilization of power batteries holds tremendous potential and serves as an effec-tive means to address energy and environmental challenges, driving sustainable development.
Although this study provides practical guidance for decision-making for battery manufactur-ers engaging in cascade utilization and governmental departments attempting to implement EPR regulations on nondurable goods, it does not consider that a certain degree of com-petition prevails between cascade utilization batteries and new batteries.
The techno-economic analysis is carried out for EFR, emphasizing the importance of an accurate degradation model of battery in a hybrid battery energy storage system consisting of the supercapacitor and battery .
Li-ion battery technology uses lithium metal ions as a key component of its electrochemistry. Lithium metal ions have become a popular choice for batteries due to their high energy density and low weight. One n. Li-ion batteries have many applications in the real world aside from simply running the apps. Whatever you need a Li-ion battery for, you can rely on its durability, rechargeability, safety, and long-lasting power supply. Lithium batteries have become a vital part of our everyday li.
Rechargeable lithium-ion batteries have become incredibly popular for smartphones, laptops, personal digital assistants (PDAs), and other portable electronic devices. There are many reasons why so many manufacturers have adopted rechargeable Li-ion batteries, for example: Li-ion batteries used in watches are small.
Rechargeable lithium-ion batteries incorporating nanocomposite materials are widely utilized across diverse industries, revolutionizing energy storage solutions. Consequently, the utilization of these materials has transformed the realm of battery technology, heralding a new era of improved performance and efficiency.
Lithium-ion batteries have garnered significant attention, especially with the increasing demand for electric vehicles and renewable energy storage applications. In recent years, substantial research has been dedicated to crafting advanced batteries with exceptional conductivity, power density, and both gravimetric and volumetric energy.
Handheld power tools commonly use lithium-ion batteries as well. Drills, saws, sanders – they all run on rechargeable lithium packs. The high energy density of lithium allows compact battery designs that don't add much bulk. And they deliver enough power and runtime for job site use.
Digital cameras were another early mass market product to use lithium-ion batteries. Their rechargeable nature eliminated the need to constantly buy disposable batteries. Higher capacity lithium batteries now provide DSLR cameras battery lives measured in hundreds of shots per charge.
The low self-discharge rate of a typical lithium-ion battery is ten times lower than a traditional lead-acid battery. Lithium batteries are the ideal solution if a system is not continually in use. People with mobility issues have found new freedom thanks to rechargeable lithium-ion batteries.
The development of thermal, mechanical, and chemical energy storage technologies addresses challenges created by significant penetration of variable renewable energy sources into the electricity mix. Ren. Energy storage systems help to bridge the gap between power generation and demand. Energy storage employs and exploits the true fundamentals of Thermodynamics. As such, it is appropriate to begin the discussion with first principles. This section will provide an ov. The many forms of energy have resulted in a wide range of technologies that seek to store and convert energy, some of which are commercially mature and others that are currently und. 1.“BP Statistical Review of World Energy,” 68th ed., 2019.Google Scholar2.“Electricity Information: Overview,” International Ene.
The development of thermal, mechanical, and chemical energy storage technologies addresses challenges created by significant penetration of variable renewable energy sources into the electricity mix.
Energy storage technologies are undergoing advancement due to significant investments in R&D and commercial applications. For example, work performed for Pacific Northwest National Laboratory provides cost and performance characteristics for several different battery energy storage (BES) technologies (Mongird et al. 2019). Figure 26.
The ESS could be also used in case of a general blackout for the re-starting of the entire electrical system. As mentioned above, there are many applications for energy storage systems and several benefits for the electrical system where an energy storage system is present.
Research and development funding can also lead to advanced and cost-effective energy storage technologies. They must ensure that storage technologies operate efficiently, retaining and releasing energy as efficiently as possible while minimizing losses.
The earliest grid-scale energy storage technology is pumped hydroelectric storage, introduced to the grid in the 1930s. Significant capacity growth has continued since, and pumped hydro is still the dominant technology in energy storage on a capacity basis.
Energy storage systems that can operate over minute by minute, hourly, weekly, and even seasonal timescales have the capability to fully combat renewable resource variability and are a key enabling technology for deep penetration of renewable power generation.
Application process1. Submit an application You can apply for our self-generation program and for solar and battery storage rebates (if eligible) through your online MyHydro account.
Solar photovoltaic (PV) power generation is the process of converting energy from the sun into electricity using solar panels. Solar panels, also called PV panels, are combined into arrays in a PV system. PV systems can also be installed in grid-connected or off-grid (stand-alone) configurations.
Solar energy conversion and its application methods varies in wide range from passive solar to heat building to complex concentrated form to generate electricity. It is crucial to know these structures in detail and to classify them in methodical order. The constituent mechanism of primary energy sources have been briefly mentioned.
Substantial progress has been made in the area of solar power generation and application covering analysis, simulation, and hardware development and testing for efficiency maximization and cost minimization.
The majority of photovoltaic power generation applications are remote, off-grid applications. These include communication satellites, terrestrial communication sites, remote homes and villages, and water pumps. These are sometimes hybrid systems that include an engine-driven generator to charge batteries when solar power is insufficient.
A basic photovoltaic system integrated with utility grid is shown in Fig. 2. The PV array converts the solar energy to dc power, which is directly dependent on insolation. Blocking diode facilitates the array generated power to flow only towards the power conditioner.
They have also demonstrated the capability of the model in accurately simulating the I – V and P – V characteristics of the real PV module. The proposed model can also be used to design and simulate solar PV system with different power converter topologies and controllers including different MPPT control methods.
Single phase inverters are ideal for use in home appliances, power tools, office equipment, water pumping in agriculture, adjustable speed ac drives, induction heating, vehicles UPS, and grid connected applications.
A single-phase inverter is a type of inverter that converts DC source voltage into single-phase AC output voltage at a desired voltage and frequency and it is used to generate AC Output waveform means converting DC Input to AC output through the process of switching.
In addition to residential solar applications, single-phase inverters are used in small-scale wind and hydroelectric power systems to convert generated DC power into grid-compatible AC power. In conclusion, the single-phase inverter is a fundamental component for converting DC power to AC power, with widespread applications in various fields.
A typical single-phase inverter consists of several key components: DC source: This is the input to the inverter, typically a battery or solar panel. Inverter circuit: This circuit, usually composed of electronic switches such as transistors or thyristors, is responsible for converting the DC input into an AC output.
The quality of the output AC from a single-phase inverter is determined by the type of waveform it generates. There are typically three types: Square wave inverters: These are the simplest type of inverter. They generate a crude approximation of an AC waveform, but can cause problems with sensitive electronics.
The power circuit of a single phase full bridge inverter is constructed with precision, featuring four thyristors labeled T1 to T4, four diodes D1 to D4 and a two wire DC input power source denoted as Vs .
Basically there are three types of waveform of the single phase inverter: The half bridge inverter architecture serves as a fundamental building block in the realm of single phase inverters, offering a straight forward structure that efficiently converts direct current into alternating current .
Some typical applications of capacitors include: 1. Filtering:Electronic circuits often use capacitors to filter out unwanted signals. For example,. A capacitor is a passive electrical device that stores electrical energy in an electric field. It consists of two conductive plates separated by an insulating material called the dielectric. The plate. In short, capacitors have various applications in electronics and electrical systems. They are used in power supply circuits to smooth out. have many uses in electronic and electrical systems. They are so ubiquitous that it is rare that an electrical product does not include at least one for some purpose. Capacitors allow only AC signals to pass when they are charged blocking DC signals. The main components of filters are capacitors. Capacitors have the ability to connect one circuit segment to another. Capacit.
[PDF Version]These are the basic applications of capacitors in daily life. Thus, the fundamental role of the capacitor is to store electricity. As well as, the capacitor is used in tuning circuits, power conditioning systems, charge-coupled circuits, coupling, and decoupling circuits, electronic noise filtering circuits, electronic gadgets, weapons, etc.
Capacitors are widely used in various electronic circuits, such as power supplies, filters, and oscillators. They are also used to smooth out voltage fluctuations in power supply lines and to store electrical energy in devices such as cell phones and laptops. In short, capacitors have various applications in electronics and electrical systems.
One of the basic functions of capacitors in electronic circuits is filtering. Capacitors block high-frequency signals while allowing low-frequency signals to pass through. This feature is especially important in radio frequency circuits and audio circuits.
Capacitors are connected in parallel with the DC power circuits of most electronic devices to smooth current fluctuations for signal or control circuits. Audio equipment, for example, uses several capacitors in this way, to shunt away power line hum before it gets into the signal circuitry.
The capacitor (C) is an electronic component that is capable of storing charge. In electrical and electronic circuits, the capacitor is a very crucial part to store energy in the form of electrical charges. In other technical words, the capacitor is known as the ' Condensor '.
Dynamic braking: Capacitors are used in dynamic braking circuits to dissipate the energy stored in a motor. Coupling and Decoupling: Capacitors are used in coupling and decoupling circuits to provide an AC path and DC isolation. Resonant Circuits: Capacitors are used in resonant circuits to tune the circuit to a specific frequency.
In this article we investigate 4 simple yet powerful battery desulfator circuits, which can be used to effectively remove and prevent desulfation in lead acid batteries.
Sulphation in lead acid batteries is quite common and a big problem because the process completely hampers the efficiency of the battery. Charging a lead acid battery through PWM method is said to initiate desulfation, helping recover battery efficiency to some levels.
Charging a lead acid battery through PWM method is said to initiate desulfation, helping recover battery efficiency to some levels. Sulphation is a process where the sulfuric acid present inside lead acid batteries react with the plates overtime to form layers of white powder like substance over the plates.
Several manufactures have developed ways for sulfation reversal in lead acid batteries in recent years with different successes. Some pulsed charge appears to be the basis of the working processes. This is contrary to ordinary charging techniques with a steady voltage in most cases.
In this instructable a novel (resistive) pulsing approach is described for driving the lead-sulfate back into solution that is faster than the more traditional inductive method. Sulfation is not the only aging mode in lead acid batteries, so while desulfation may extend the life, it will not do so indefinitely.
The crystallized lead sulfate not only does not participate in the reaction, but also adsorbs on the surface of the electrode plate, which increases the internal resistance of the battery and affects the charge and discharge performance of the battery and the battery capacity3.
A battery desulfator is an electronic device that reverses the sulfation process in lead-acid batteries, restoring their capacity and extending their lifespan. It works by sending high-frequency pulses through the battery, which breaks down the lead sulfate crystals and allows them to be reabsorbed into the electrolyte.
The basic principle of a boost converter consists of 2 distinct states (see Figure 2):In the on-state, the switch S (see Figure 1) is closed, resulting in an increase in the inductor current;In the off-state, the switch is open, and the only path offered to inductor current is through the flyback diode D, the capacitor C and the load R. The input current is the same as the inductor current, as shown in figure 2.
Efficient regulation ensures that the boost converter can maintain a constant output voltage despite variations or changes in the input voltage which contributes performance and its reliability. Hence this working mode makes the boost converter efficiency in stepping up voltage levels.
The basic circuit topology of a boost converter consists of the following key components: Inductor (L): The inductor, which stores and releases energy throughout the switching cycles, is an essential part of the boost converter. Its major job is to preserve energy storage during conversion while controlling current flow.
In this study, a simulation of a mathematical model for the photovoltaic module and DC-DC boost converter is presented. DC-DC boost converter has been designed to maximize the electrical energy obtained from the PV system output. The DC-DC converter was simulated and the results were obtained from a PV-powered converter.
To reduce voltage ripple, filters made of capacitors (sometimes in combination with inductors) are normally added to such a converter's output (load-side filter) and input (supply-side filter). Power for the boost converter can come from any suitable DC source, such as batteries, solar panels, rectifiers, and DC generators.
Boost converter from a TI calculator, generating 9 V from 2.4 V provided by two AA rechargeable cells. A boost converter or step-up converter is a DC-to-DC converter that increases voltage, while decreasing current, from its input (supply) to its output (load).
Boost converters are a type of DC-DC switching converter that efficiently increase (step-up) the input voltage to a higher output voltage. By storing energy in an inductor during the switch-on phase and releasing it to the load during the switch-off phase, this voltage conversion is made possible.
When a violent short circuit occurs, the battery cells need to be protected fast. In Figure 5, you can see what's known as a self control protector (SCP) fuse, which is mean to be blown by the overvoltage control IC in case of overvoltages, driving pin 2 to ground. The Mcu can communicate the blown fuse's condition,. Here is implemented a low side current measurement, allowing direct connection to the MCU. Keeping a time reference and integrating the current. Temperature sensors, usually thermistors, are used both for temperature monitor and for safety intervention. In Figure 7, you can see a thermistor that controls an input of the overvoltage control IC. This artificially blows the SCP. Battery cells have given tolerances in their capacity and impedance. So, over cycles, a charge difference can accumulate among cells in series. If a weaker set of cells has less capacity, it will charge faster compared to others in. To act as switches, MOSFETs need their drain-source voltage to be Vds≤Vgs−VthVds≤Vgs−Vth. The electric current in the linear region is Id=k⋅(Vgs−Vth)⋅VdsId=k⋅(Vgs−Vth)⋅Vds,.
[PDF Version]The development ecosystem for battery management systems (BMS) includes various tools, software, and hardware components that are used to design, develop, test, and deploy BMS for diferent applications. Here are some of the key components of the BMS development ecosystem:
Robust BMS design is essential to maintaining a safe environment for the operator, maximizing pack reliability, and minimizing warranty costs. Arrow has the BEVOP demo kit from Neutron Controls available, it serves as a Battery Management System in a nutshell using Infineon components.
It consists of hardware and software components that work together to control the charging and discharging of the battery, monitor its state of charge and health, and provide alerts or shut down the system in case of any faults.
The BMS may use a combination of methods to calculate the SOC of the battery to improve the accuracy and reliability of the estimation. measurement: The BMS measures the voltage of the battery and each individual cell when it is at rest and not under load to eliminate voltage transients generated during operation.
Protection Circuits are crucial components in a BMS, safeguarding Li-ion batteries from potential risks such as overcharge, over-discharge, and short circuits. These protection circuits monitor and prevent overcharging, a condition that can lead to thermal runaway and damage. They may include voltage limiters and disconnect switches.
The existing BMS techniques are examined in this paper and a new design methodology for a generalized reliable BMS is proposed. The main advantage of the proposed BMS compared to the existing systems is that it provides a fault-tolerant capability and battery protection.
At its most simple, a capacitor can be little more than a pair of metal plates separated by air. As this constitutes an open circuit, DC current will not flow through a capacitor.
A capacitor is not well-described as an open circuit even in DC situations. I'd rather describe it as a charge-controlled ideal voltage source in that it can deliver and accept arbitrarily high currents at the cost of adapting its voltage depending on the delivered charge.
Capacitor: at t=0 is like a closed circuit (short circuit) at 't=infinite' is like open circuit (no current through the capacitor) Long Answer: A capacitors charge is given by Vt = V(1 −e(−t/RC)) V t = V (1 − e (− t / R C)) where V is the applied voltage to the circuit, R is the series resistance and C is the parallel capacitance.
Short Answer: Inductor: at t=0 is like an open circuit at 't=infinite' is like an closed circuit (act as a conductor) Capacitor: at t=0 is like a closed circuit (short circuit) at 't=infinite' is like open circuit (no current through the capacitor) Long Answer:
Then this is a closed circuit that will charge the capacitors. (sorry for the ascii circuit, the -| |- are capacitors, the MMM is a resistor, and the (-+) is a voltage source). Your argument is: If the circuit is open, the current must be zero. Consequently the field must be zero.
The circuit is open since the switch is open. My book says that the capacitor will only be charged when the switch is closed, but I don't see why this is true. I would expect the capacitor to be charged a little - not as much as if the circuit is closed, but still charged none the less.
Seeing it really helps you grasp what's going on. A capacitor looks like an open circuit to a steady voltage but like a closed (or short) circuit to a change in voltage. And inductor looks like a closed circuit to a steady current, but like an open circuit to a change in current.
Solar panelsare not new to us and today it's being employed extensively in all sectors. The main property of this device to convert solar energy to electrical energy has made it very popular and now it's being strongly considered as the future solution for all electrical power crisis or shortages. Solar energy may be used. But thanks to the modern highly versatile chips like the LM 338 and LM 317, which can handle the above situations very effectively, making the charging process of all rechargeable batteries. The second design explains a cheap yet effective, less than $1 cheap yet effective solar charger circuit, which can be built even by a layman for harnessing efficient solar battery charging. In our 4rth automatic solar light circuit we incorporate a single relay as a switch for charging a battery during day time or as long as the solar panel is. The 3rd idea teaches us how to build a simple solar LED with battery charger circuit for illuminating high power LED (SMD)lights in the order of 10 watt to 50 watt. The SMD LEDs are.
[PDF Version]Simple solar charger circuits are small devices which allow you to charge a battery quickly and cheaply, through solar panels. A simple solar charger circuit must have 3 basic features built-in: It should be low cost. Layman friendly, and easy to build. Must be efficient enough to satisfy the fundamental battery charging needs.
Place the solar panel in sunlight. Check the battery voltage using digital multi meter. Circuit is simple and inexpensive. Circuit uses commonly available components. Zero battery discharge when no sunlight on the solar panel. This circuit is used to charge Lead-Acid or Ni-Cd batteries using solar energy.
Here is the simple circuit to charge 12V, 1.3Ah rechargeable Lead-acid battery from the solar panel. This solar charger has current and voltage regulation and also has over voltage cut off facilities. This circuit may also be used to charge any battery at constant voltage because output voltage is adjustable.
These solar cells should be able to charge one 1.2 volt, battery, or two 1.2 volt batteries in series at a rate of 20 mA for 200 mAh battery, 30 mA for a 300 mAh battery, or 60 mA for a 600 mAh battery. The charging circuit for these batteries is simple, a solar cell connected to a diode then connected to a NiCad battery.
Below is the circuit diagram for it. The solar cells positive terminal is connected through the diode to the positive terminal of the 1.2V battery. If the voltage of the solar cell drops below 1.4 volts then with the 0.2V the blocking diode takes there wont be enough potential to charge the 1.2V battery.
Solar battery charger operated on the principle that the charge control circuit will produce the constant voltage. The charging current passes to LM317 voltage regulator through the diode D1. The output voltage and current are regulated by adjusting the adjust pin of LM317 voltage regulator. Battery is charged using the same current.