Abstract
Electrical power systems are accessible in renewable energy systems, and hybrid battery systems or energy storage systems (ESS) are capable of delivering uninterruptible power to the demand even if faults occur. Additionally, the energy storage device increases system dynamics during power fluctuations. A photovoltaic (PV) battery hybrid system with an ESS link is considered, and an impact leveling management system is planned to transfer the ability to load as well as the battery. Electricity generation is vital, and also the method is fairly complicated. The goal of lowering production prices, maintaining instrumentation, and its fuels, all play necessary roles within the method. As a result, producers should import fuel to satisfy the electrical demand, the assembly value rises. We are considering using renewable energy sources to avert a harmful economic imbalance. We tend to introduce a replacement system to complete the load of alternative energy. To boost inertia and improve frequency responsiveness, load side inverters linking PV to grid and energy storage systems are used on a utility-scale (ESS). Furthermore, with growing PV penetration, independent development of PV and ESS linking to the load and the battery is one of the alternatives for steady operation of the standalone system. The associate integrated the idea for PV and ESS integration to AC load and ESS and it is used for automotive applications.
1. Introduction
Renewable energy growth has been steady throughout the last two centuries, not only are there growing concerns about climate change and rising oil prices but there is also strong backing from renewable energy legislation. One of the most prevalent types of renewable energy is photovoltaic (PV) systems. In contrast to traditional fossil fuels such as coal, oil, and gas, it is an attractive energy source since it is renewable, limitless, and nonpolluting. Photovoltaic power generation has become one of the most popular renewable energy sources as a result of these unique properties [1].
To convert sunlight into electrical energy, photovoltaics employ the photoelectric effect. Photovoltaic systems immediately transform the sun’s beams into useable power. Solar irradiance and temperature have such a major impact on PV generation. As a result, the amount of electricity produced by solar systems varies. Aside from the clean conversion of solar energy into electrical energy, one of the constraints of photovoltaic systems is their vulnerability. Their accumulation varies with solar irradiation and temperature. As a result, installing a maximum power point tracker (MPPT) embedded with an artificial neural network (ANN) controller enhances the durability of solar power, where this increased energy source will be stored as ESS when the primary solar energy source has been unable to match the load requirement, the backup supply will take place. PV modules produce power by absorbing the energy from solar radiation. In this case, solar radiation is not constant, it varies time to time, and this variation depends on the natural calamities of weather conditions. In this case, an MPPT approach is used to calculate the maximum power and watch the solar radiation throughout the day in order to determine the most extreme instant when the PV modules create the most notable power from their framework. The output power depends on the solar irradiation and temperature of the atmosphere. When demand outweighs generation, the primary solar source will power the help compensate. [2–7].
However, if this low output level can be increased by employing a boost converter, stepping the voltage, and using a voltage source inverter (VSI), reconfigured on the load side dependent on demand. It is demonstrated how solar power is employed as one half of our system to power the load. This controller is adjusted using the ANN, and the symmetrical components are used for harmonic separation [8–12]. The ANN controller provides an alternate lowpass filter in isolating constant and oscillating components in distorted signals.
The ANN’s linear mapping of input and output yields oscillating components of extracted instantaneous active power. When the sun does not deliver enough irradiation to the PV panel to produce maximum output to the load, the battery’s stored energy is used to power the generation section [13–15]. Because the power generated by the battery is time-dependent and also depends on the state of charge of the battery. As a result, the electricity from the battery is used to power a brushless direct current motor (BLDC) coupled to the generator [16–18]. The generator then generates a voltage, which is monitored and used to power the load. When solar radiation is normal for producing demand electricity, energy is usually produced by employing PV modules [19–27].
2. Literature Review
Vladimir Burlaka investigated the conversion is conducted in a single step by adopting a distinct topology evolved from LLC dual active bridge converters. Controlling the converter’s ratio and equivalent output impedance is done by integrating PWM and frequency control. The envisioned converter can be exploited as an uninterruptible source of power that works unrated, features pure sinewave output, allowing for both DC-AC conversions in battery backup mode and AC-DC conversion for recharging when connected to the mains. It may also function as a bidirectional grid-tie inverter, producing electricity between the mains and a DC voltage source.
Omar Abdel-Rahim explicates that PV operations, for a case, need to raise the output voltage to an advanced voltage position. Especially, compared to other transformer topologies, any use of coupled inductors in some topologies offered lesser advantages similar as reduction switching device stress and enhanced converter voltage gain the present architecture achieves significant voltage gain. Voltage demands on active MOSFETs are lower than half that of the output voltage.
Sudha Bansal explicates that thus in the PV power conditioning units, high-frequency converters minimize the system size. DC-DC converters are utilized for energy storage and reconnecting downstream devices. This energy can be extracted from the Solar System. Individual controllers are offered to appropriately regulate these DC-DC converters. As a consequence, the entire structure becomes interlinked, allowing for a wide range of dynamic interactions. The PV array’s voltage can be controlled by a DC-DC converter circuit. This study explores a photovoltaic (PV) system with a PI-controlled secluded full-bridge bridge dc/dc conversion that may be utilized as a standalone power source in faraway missions.
Tunku Muhammad Nizar Tunku Mansur intricates the solar PV system’s low DC output voltage can be used regionally before supplying surplus power to the transmission network through the oblique connection. These PV modules or arrays can charge rechargeable batteries using a PV battery charger for a range of different applications such as solar PV off-grid structures, satellites, solar automobiles, street lamps, base transceiver stations, and building integrated PV systems where solar energy can be stored for winter or rainy seasons, at night, and so on.
Mayank Kumar interpolates that the external DC microgrid is used to increase end-user security and power quality. By charging and discharging the battery, the bidirectional converter monitors the independent DC bus voltage and maintains the power balance between PV power output and load power demand for deficit spending energy scenarios. The numerous modes of operation are addressed, and numerous controller design features are presented to balance the load energy usage, concerning the availability of source power and the battery’s state of charge (SOC). Power converter losses are also taken into account for appropriate power balance studies.
Shradha Deshmukh explicates the fluctuation of PV, which a solar PV control system requires. PV device modelling and analysis are therefore provided for low voltage in DC load applications. To increase PV voltage and provide a battery backup interface, a multimodal controller comprising DC-DC converters is utilized. The technology is meant to eliminate overloading and discharging by maintaining the device’s state of charge and reducing dumps load consumption. Depending on the load, the PV acts in either the maximum power point algorithm with incremental conductance or the intended voltage regulation phase.
Epuganti Sri Harsha interpolates that the ESSs are incorporated into the DC bus and provides an uninterrupted power supply to the load. In other applications that demand multiple battery banks, the battery banks are directly connected to the DC bus, and this form of design is not cost-effective. Using a modest number of battery banks is more convenient for consumers of capacity and cost, with the introduction of a bilateral DC-DC converter in between ESS and the DC bus, short-string string battery banks may be used. Inverters in uninterruptible power supply systems and DC microgrids, aircraft power systems, electric vehicle charging systems, and data centers demand high DC voltage, which can be supplied by these converters.
3. Materials and Methods
Figure 1 illustrates the proposed block diagram. The DC supply is coupled to a boost converter, which boosts the PV voltage. The battery is linked to the bidirectional converter, which retains the DC connection and charges and unloads the battery based on the available power and load power. The control system algorithm is designed to ensure that the level of the SOC batteries is kept within acceptable limits. The reference voltage is provided to the controller through the MPPT algorithm. The flowing power from the PV to the load contains an integrated converter, the looping system monitored by the MPPT technique, and a combination of the ANN controller. MPPT tracks maximum power from the PV module that measured value sensed by the ANN controller in that controller calculated value difference between the maximum value and the allowable input to the converter. If any variation in the input to the converter the looping sends the error signal to the ANN controller and the controller erects the difference with the help of the energy storage system. Solar Vpv and Ipv feedback signals are utilized for decision-making at photovoltaic terminals. The control variables are provided to the reference signal for active power, which may be regulated and retrieved from a controller. If the power at the specified radiation and temperature reaches the maximum PV power attainable, the actual power produced by Ppv would be the maximum power.
If the solar energy falls below a certain threshold, the PV modules will struggle to provide the rated voltage. In the first part of the process, we the power in the battery, pulse width modulation spike voltage injector technique, PI-controlled converter with minimum ripple voltage, constant current and constant voltage method, and variable voltage and constant current are the methods used to improve the battery charge controller and in the second half, we use the battery to run the brushless DC motor, which drives the induction generator to generate the rated AC voltage. The rotating component of a squirrel-cage induction motor is known as a squirrel-cage rotor.
It is made up of a steel lamination cylinder with aluminum or copper conductors implanted in its surface. When a nonrotating stator winding is coupled to an alternating current power source, the alternating current in the stator generates a rotating magnetic field and that voltage is being monitored and used to run the loads.
Figure 2 illustrates that light and temperature affect their features. Photovoltaic cells create electricity by absorbing sunlight. PV arrays are made up of PV modules that are connected in parallel and series. Cells are grouped to form panels or modules. PV modules produce electrical power which is successive voltage and current. Here, the current from the modules is near to the constant value and the voltage from the modules are varying that depend on the solar irradiation and the temperature. If the level of radiation from the solar is reduced, then the voltage from the modules is also reduced then power extraction is reduced. In contrary, the hike in the solar radiation voltage also increased which may cause damage to the system to prevent that circuit damage voltage controller is used to control voltage drop or hike and output the constant voltage to the system. The voltage and current produced at the terminals of a PV may be used to power, not just a direct current load, but can also be linked to an inverter to produce alternating current. Figures 3 and 4 depict I–V parameters and P–V parameters of the photovoltaic cell.where k = Boltzmann constant (JK−1). q = electric charge. T = cell temperature (K). ID = diode current (A). A = diode factor. RS = resistance in series (Ω). RP = resistance in parallel (Ω). NS = number of cells linked in series. NP = number of cells linked in parallel. ISC = solar short circuit current (A). IPV = photovoltaic (PV) current (A). VPV = photovoltaic (PV) voltage (V). T = module temperature (K).
Rated power tendency is that entire instant discharge capability (in kilowatt-hours (kW)), or the greatest rate discharge that the ESS can accomplish beginning from a fully charged condition. The largest quantity of stored energy is referred to as energy capacity. The charge storage may discharge at its capacity before exhausting its energy capacity is referred to as storage duration.A = area of cathode. c = density of lithium-ion electrode. F = Faraday’s constant. n = ratio of the redox process. R = gas constant. T = absolute temperature.
The amount of time or cycles a battery storage system can offer regular charging and discharge before failure or significant degradation is referred to as the cycle life/lifetime. Total resistance is equal to the summation of internal resistance and external resistance. If internal resistance increases current drop inside the battery is high, which affects the efficiency of the battery. External depends on which type of load is connected to the external terminal circuit. Consideration of dimension also plays a vital role in the prediction of the efficiency, because if the area of the battery increases, the weight also increases; due to this expansion of size, large anode and cathode rods are placed, and filled with more electrolyte, and the space for separation is also inbuilt with an expansion of dimension.
When a battery’s stored charge (or energy) is drained by internal chemical processes rather than being discharged to conduct work for the grid or a customer, this is referred to as self-discharge. Self-discharge is expressed as a percentage of charge lost over a certain period, lowers the amount of energy available for discharge, and is an essential characteristic to consider in batteries designed for long-term use. A battery’s state of charge, based on a percentage, shows its current degree of charge and varies from entirely depleted to fully charged. The state of charge of a battery at any one time influences its capacity to supply power or auxiliary services to the grid.
Rolling efficiency is calculated by combining the energy-charged to the battery with the energy liberated from the battery. It might represent the entire converter efficiency of the battery system, encompassing self-discharge as well as other electrical losses. Table 1 shows the storage specification.
3.1. Photovoltaic System with Battery Storage Using the Inverter and Converter
In the proposed system, solar power is harvested from solar cells using PV modules. Light energy is turned into electrical energy as a result of this process. When this procedure is complete, the DC voltage generated by the PV module is connected to the DC-DC boost converter, which steps the voltage and uses a voltage source inverter to invert and reconfigure it on the load side based on demand. Table 2 shows the commutation technique for the BLDC motor.
Figure 5 represents how solar energy is used as one-half of our system to power the load. If the solar energy goes below a specific level, the PV modules will struggle to produce the rated voltage. We store some energy in the battery in the first part of the process, and in the second half, we use the battery energy to power the brushless DC motor, which drives the induction generator to create the rated AC voltage, which is monitored and used to power the loads. Because this is a loop system, it will continue to supply power for a long time.
The numbers of switches are estimated as follows:where k is the no. of basic unit, then, the no. of switches are as follows:
The no. of sources are estimated as follows:
Then the no. of sources are as follows:
The no. of levels are obtained as follows:
The no. of levels are as follows:
The output voltage is determined as follows:
Then, the output voltage is as follows:
3.2. Modes of Operation
3.2.1. Mode A
Figure 6 explicates how the charge management circuit of a solar battery charger ensures that the voltage remains consistent. The charging current flows through the voltage regulator through diodes D1 and D3. The voltage regulator controls the output voltage and current. The main normal function of the inverter is to transition DC input to three-phase AC output. A basic three-phase inverter is comprised of three single-phase inverter switches, each of which may be connected to one of three load terminals. PWM may be utilized in three-phase inverters, just as it can in single-phase voltage source inverters. Three sine waves phase-shifted by 120° with the frequency of the desired output voltage are compared with a very high-frequency carrier triangle, and the two signals are mixed in a comparator whose output is high when the sine wave is greater than the triangle and low when the sine wave, or modulation signal, is smaller. The switches (Q1, Q2, Q3, Q4, Q5, and Q6) used in the inverter have a ratio, and switching can occur after every 60 degrees angle.
Iph = phase current. PF = power factor. Vrms = RMS voltage.
The ANN controller is the control unit of the system that measures all of the output values from all sections of the system. It measures inverted voltage and matches the algorithmic condition, if the value is mismatched to the initialized condition, then the controller erects the aligned voltage to match the grid voltage.
3.2.2. Mode B
Figure 7 explicates how the BLDC motor is driven by a direct current source, and the basic drives of BLDC motors have been investigated to provide a helpful reference for primary research traditionally. Because the evolution of the rotor and through motor’s electromagnetic force, on the other hand, is indistinguishable from that of a generator, and therefore, the motor both receives and generates its own voltage. This phenomenon has been described as opposing electromotive power, or back EMF, and it is proportional to the motor’s rotor velocity. Back EMF may be used to calculate rotor speed in a motor, but position sensors are necessary. Back EMF control of a motor is a difficult operation; most sensorless BLDC motors are controlled by a microcontroller. Commutation occurs at brushes through which reverse current passes in brush DC motors, while in BLDC motors, commutation happens through the use of switching sequences of a three-phase inverter, and hence, this is referred to as electronic commutation. As a result, hall sensors are put on the motor every 60 degrees, the produced hall signal is evaluated, and the inverter functions in the right sequence to power the BLDC motor. GVTC is an automotive gearbox; this is a very effective method to produce variable torque. Geometric variable torque converter (GVCT) is input by the BLDC motor and the torque converter is placed in between the motor and the generator circuit. Practical losses are included in the torque conversion methodology. Friction loss and stress losses are combined to be mechanical losses The mechanical output of the DC motor is delivered into the induction generator, which generates AC power to power the appropriate electrical load.F1 = force, M1 = mass of object, G1 = gravity constant, and f2 = friction.
The amount of force required to run the generator is calculated; to achieve the rated speed of operation, the torque produced by BLDC is measured and input to the variable torque converter setup, which is input by the BLDC motor, and torque is multiplied with respect to gear ratio to the generator speed ratio.TD = torque, F1 = force, Dr = radius of wheel. VT = variable torque output. TD = torque developed. TC = torque conversion ratio. ML = mechanical losses.
4. Results and Discussion
MATLAB has been utilized as a modeling and simulation tool to enhance the researcher’s data representation and analysis abilities. In this part, a Li-ion battery is modeled and simulated using MATLAB software.
The output waveforms of battery current and voltage are shown in Figures 8 and 9. The ripple in the battery current is 8 A, and the battery voltage is 14 V.
Voltage sources are employed to charge the battery in Figure 10, and simulations for varying charge current and voltage for Li-ion batteries are performed.
The state of charge (SOC) of a battery determines how much power it can deliver in Ampere-hours (Ah), as seen in Figure 11. When a battery losses energy, the voltage drops, and the current rises. In this situation, the bidirectional port is used to recharge the battery.
Figure 12 shows the plots of torque vs. time, as a result, the induced e.m.f. in the rotor causes the current to flow in the opposite direction of the revolving magnetic field in the stator, resulting in a twisting motion or torque in the rotor.
Figures 13 and 14 show the simulation results describing rotor speed response, SCIG model control works extremely well and has very good dynamic and steady-state performance. Figure 15 shows the different phase voltage responses.
As shown in Figures 15 and 16, the inverter converts DC voltage from the battery into AC voltage and is connected to the battery and load. In a three-phase supply system, the sixth harmonic in an AC voltage is reflected as a dominant harmonic on the DC side. The VSI’s fundamental frequencies are predicted to match the rated speed and the lowest speed of the BLDC motor critical for running the SCIG generator.
5. Conclusion
The study successfully described and simulated the use of a bidirectional DC-DC converter to control a PV system with MPPT. Additionally, a boost converter stage was successfully simulated and modeled to increase the PV output voltage. A closed-loop control system was implemented using the ANN controller. Increased conductance algorithms were incorporated in the MPPT controller. MPPT controllers using improved conductance algorithms can help eliminate steady-state ripples. By creating SOC limits and considering them in the system control, it is difficult to use dump load and permits another battery life. In addition to studying and simulating the ANN control technique, the bidirectional converter has also been analyzed and it is used for automotive applications.
Data Availability
The data used to support the findings of this study are included within the article.
Disclosure
The study was performed as a part of the Employment of Authors.
Conflicts of Interest
On behalf of all authors, the corresponding author states that there are no conflicts of interest.