Abstract

This study investigates the design and performance of a grid-connected photovoltaic (PV) system for electric vehicle (EV) charging. The system utilizes 48 PV panels arranged in four parallel strings of 12 series panels each. A 25 kVA Huawei inverter converts the generated DC power to 24.3 kW AC, supplying the EV charger. A net metering system tracks both imported and exported energy, balancing the customer's needs by recording active and reactive energy in both directions. The proposed system provides the user with the ability to power their EV using solar energy. Design software (PVsyst, SketchUp, and AutoCAD) was used to create the architectural design, shading analysis, and electrical wiring diagram, including connection points and protection devices. Power consumption calculations for the EV were performed to ensure sufficient power supply from the PV system. Preliminary results indicate that the solar station can potentially generate 54 MW annually, resulting in cost savings of 9,375 K SAR and a return on investment (ROI) of 529.2%. The payback period is estimated at 7.2 years.

1. Introduction

The transportation sector significantly contributes to global warming through greenhouse gas emissions, particularly carbon dioxide ¹. This calls for a shift towards clean and sustainable energy sources for powering vehicles. This paper explores the design and implementation of a grid- connected PV system to power an EV charger. The primary focus is on the environmental benefits achieved by minimizing reliance on fossil fuels and greenhouse gas emissions ². Figure 1 shows the suggested EV charging PV station.

A. Motivation for Solar Energy Utilization in Saudi Arabia

Saudi Arabia, with its abundant sunshine throughout the year, presents an ideal location for harnessing solar energy. The country aims to significantly increase solar energy utilization as a clean, renewable, and sustainable alternative to conventional energy sources. These traditional sources contribute to global warming through greenhouse gas emissions, particularly carbon dioxide. Solar energy offers a solution by generating electricity through photovoltaic technology ³.

B. Proposed System Design

The system comprises two main parts:

1. EV Charger: This unit is conveniently installed within a home for charging EVs.

2. Grid-Connected PV Station: This station includes:

™ Solar panels

™ Inverters (convert DC to AC electricity)

™ DC and AC cables

™ Power and protection panels

C. Operating Requirements and Target Users

The system requires specific operating conditions for optimal performance:

• Internal temperature below 40°C (104°F)

• Internal humidity below 50%

• Sufficient surface area for solar panel installation

• Reliable internet access

This system offers benefits for a wide range of users:

• Residential homeowners with EVs can achieve convenient and environmentally friendly charging.

• Businesses (hospitals, hotels, factories) seeking to reduce their environmental impact can utilize the system for a more sustainable operation.

D. Proposed Idea and Limitations

This project focuses on a limited-scale system that demonstrates the concept and its benefits. The design can be readily expanded for commercial or large-scale applications.

E. Assumptions and Limitations

Certain assumptions are made for project execution:

• Electrical components are housed in a waterproof case for protection against external elements.

• Free software is used to minimize project budget.

• Online monitoring is the default mode for immediate alarm notification in case of system issues.

The study acknowledges limitations inherent to the initial design:

• The initial study is limited to one EV and one EV charger.

• EV charging is limited by lithium-ion battery temperature constraints.

• All components are protected by suitable devices to ensure system safety.

• Only one user can remotely access the monitoring and control system.

F. Expected Deliverables for Commercial Implementation

For commercial implementation, the system includes the following components delivered to the client:

• Waterproof case containing EV charger, inverter, switches, and protection devices

• Solar panels and steel structure

• AC/DC cables, power and protection panels

• Instruction manual

• Client registration on inverter company website for device access

G. Software Used in the Project

This project utilizes several software tools for design and simulation:

• AutoCAD: This software is used for 2D/3D design and drafting of technical drawings related to the system components.

• SketchUp: This software is used for 3D modeling and design to create a visual representation of the system layout.

• PVsyst: This specialized software is used for photovoltaic system design and simulation, allowing for performance optimization.

This research explores the potential of a solar-powered EV charger system for reducing environmental impact. The paper details the system design, target users, and limitations. The project demonstrates the viability of using renewable energy for EV charging and contributes to a more sustainable transportation sector.

A. Proposed Methodology

B. Objective of the Task

The primary objective of this project extends beyond simply providing convenient charging for new EVs. It aims to achieve a multi-faceted impact:

1. Environmental Sustainability: By incorporating a grid-connected PV system, the proposal significantly reduces reliance on fossil fuels for EV charging. This translates to a decrease in greenhouse gas (GHG) emissions, particularly carbon dioxide (CO₂), which are major contributors to global warming ¹.

2. Cost Savings: The system leverages solar energy, a free and renewable resource, to power EVs. This reduces dependence on traditional grid electricity, potentially leading to cost savings on energy bills for users.

C. Proposed system design

The proposed Solar EV Charger system is intended to supply Power to EV through solar PV grid connected system.

Figure 2 shows the structure of the proposed system and the provided specifications and options of the proposed system. The end user can supply power to his EV charger by his PV grid connected station. It shows the High-Level description of the proposed solar PV grid connected system with EV charger.

D. Arch and Electrical Structure of the Proposed Grid Connected System with EV charger

The proposed design of the project is shown in Figure 3, where it presents the block diagram of the proposed system components and the connection between PV Panels (Trina / Jinko 535 Wp) and the grid connected inverter (Huawei / Sun Grow 25 KVA) to the EV charger for 2 EVs lucid air Electric Car

E. Sequence of activities in the proposed Grid Connected with EV charger system.

The proposed design of the project shown in Figure 4, EV Charger’s needs is covered daylight usage only , when output energy of the PV grid connected system is ready, solar station provides all produced energy to the load with counting the exported energy by the Net Meter’s Recording recordings that clears the sky from this math by recording the active and reactive energy in load direction and count the load energy consumption and PV Energy Production and calculate whether it's more or less the customer’s needs.

F. The Proposed Grid Connected with EV Charger System

In grid-connected PV systems, power flow is managed predictively. When solar generation falls short of load demand, the grid supplements the deficit.

Conversely, excess PV generation is fed back to the grid. The inverter plays a critical role in this dynamic exchange. During sufficient sunlight hours, the PV system generates DC voltage (𝑉_𝐷𝐶) and current (𝐼_𝐷𝐶). The inverter then converts this DC output to AC at the maximum power point (MPP) voltage (𝑉_𝑚𝑝) and current (𝐼_𝑚𝑝𝑝) to match grid requirements. Grid synchronization occurs when the grid voltage (V) and frequency (F) meet specified stability conditions (e.g., V = 380V, F = 60Hz). In the absence of a stable grid signal, the inverter remains unsynchronized and ceases AC power output. As shown in Figure 5.

2. Sequence of Calculations and Designs According to EV Power Consumption

The interactions and activities between the two ends of the proposed system are graphically described in the activity sequence diagram shown in Figure (3), Where the Solar Power supplies the EV charger and the grid, here are the steps of calculations to adjust the required power for the EV consumption with the supplied PV power.

A. Power consumption of EV

It is suggested that a Lucid Air Grand Touring vehicle be used for this design, and the required power calculations.

According to Lucid Motors, Lucid Air Grand Touring has a power consumption of 112 kWh ⁴ as shown in Figure 6.

B. Calculation of the Required Power Generation to supply 112 kWh

This section outlines the calculation of the required PV system size to support EV charging needs the goal is to size the PV system such that it can generate enough energy to meet the daily EV charging requirement.

Saudi Arabia experiences an average of five Peak Sun Hours (PSH) per day ⁵. Therefore, the required AC power per hour to meet the daily charging needs is calculated as 112 kWh / 5 h = 22.4 kW.

To account for system inefficiencies, a derating factor of 95% is applied. System inefficiencies typically include inverter losses (around 2%), cable losses (around 2%), and connection losses (around 1%). With this derating factor, the required DC power from the PV panels is calculated as 22.4 kW / 0.95 = 23.5 kWp.

C. Calculation of the Power Generation of PV Panels.

This section describes the selection and sizing process for the photovoltaic (PV) panels used in the system design. Trina Vertex 535 Wp solar panels were chosen due to their high efficiency, readily available in the region. The key electrical specifications of the Trina Vertex 535 Wp panel are summarized below:

Maximum Power (Pmax): 535 W Open-Circuit Voltage (Voc): 37.7 V

Maximum Power Voltage (Vmp): 31.0 V

Short-Circuit Current (I_sc): 18.36 A Maximum Power Current (I_mp): 17.28 A. ⁶

To determine the number of PV panels required to meet the system's power needs, the following equation was used:

Number of Panels = Total System Power (W) / Power per Panel (Wp) (1)

Based on the previously calculated required DC power of the system (23.5 kWp) and the individual panel power (535 Wp), the preliminary number of usable panels is estimated as:

Number of Panels ≈ 23.5 kWp / 535 Wp ≈ 44 panels.

D. Calculation of the Power transformation of Grid Connected inverter

This section details the selection and sizing process of the grid-tied inverter for the photovoltaic (PV) system. The chosen inverter is the Huawei SUN2000-25KTL, a 25 kVA inverter with a unity power factor (PF = 1) ^{8, 9}. Key electrical specifications of the inverter are provided below:

• Maximum Power Output: 25 kVA

• Power Factor: 1

• Maximum Input Voltage (Voc): 1000 V

• Maximum Power Point Voltage (Vmpp): 650 V

• Maximum Power Point Tracking (MPPT) Efficiency: 98%. ^{7, 8, 9, 10}

1). Determining the Number of Series-Connected Panels

The number of PV panels that can be connected in series is limited by the inverter's maximum input voltage (Voc).

To calculate the number of series-connected panels, the following equation was used:

Number of Series Panels = Inverter Input Voltage (V) / Panel Maximum Voltage (V) (2)

Based on the inverter's maximum input voltage (650 V) and the individual panel's open-circuit voltage (assumed to be 51 V based on Trina Vertex 535 Wp specifications), the initial calculation suggests connecting approximately 12.7 panels

in series. However, due to winter temperature coefficient (Temp Co) effects, the actual number of series-connected panels will be limited to 12 to ensure the voltage remains within the inverter's safe operating range during colder months.

2). Determining the Number of Parallel Connections

The total number of PV panels required is divided by the number of panels connected in series to determine the number of parallel connections. Given the preliminary requirement of 44 panels and 12 panels connected in series, the initial calculation suggests approximately 3.7 parallel connections.

3). Final Number of Usable Panels

In practice, the number of parallel connections is typically an integer value. To achieve the closest integer value while maintaining system efficiency, a final design of 4 parallel strings, each with 12 series-connected panels, is chosen. This results in a total of 48 usable panels with a combined peak power output of approximately 25.67 kWp.

E. Electrical Design of the proposed Grid Connected system with EV Charger

According to the Load Requirement, we need 25.6 kWp with total 48 PV panels divided into 4 parallel lines each line has 12 series panels , with one inverter Huawei 25 KVA , transform these DC power to 24.3 kW AC to Supply the EV charger , when output energy of the PV grid connected system is ready, solar station provides all produced energy to the load with counting the exported energy by the inverter’s recordings that clears the sky from this math by recording active and reactive energy in load direction and counting the load energy consumption and PV Energy Production and calculating whether it's the customer’s needs.

The PVsyst software was used to simulate the system's performance throughout the year. The results, presented in Table 1, provide a detailed breakdown of the monthly energy production. This data allows for an assessment of whether the system's generation meets or exceeds the customer's electricity needs.

3. Architecture Design of the Proposed Grid Connected System with EV Charger

The output of a PV array can significantly reduce if even just one module is shaded. So, we use sketch-up software to determine the following:

Natural landscape: The software incorporates data on surrounding topographical features (hills, trees) that may cast shadows on the PV array throughout the day.

Other buildings: Any nearby structures that could potentially shade the array during specific times are modeled in SketchUp.

Roof sections: The software allows for detailed modeling of the client's roof, considering its orientation, pitch, and potential shading from roof elements (e.g., chimneys, vents).

The shading analysis will be conducted for the specific location in 7751 Jabal Al-Nour Neighborhood, Makkah, Saudi Arabia ⁸ as shown in Figure 7.

The Available Area is only 190 m², with total 48 Installed panels, which they are enough for the required power 25 kWp.

offsetting electricity purchases from the grid, resulting in reduced electricity costs, influenced by prevailing grid

4. The Economic Assessment of a Grid-connected PV

The economic assessment of a grid-connected PV system involves analyzing both initial costs and ongoing benefits. The initial system cost encompasses expenses related to design, equipment, installation, commissioning, and paperwork, totaling 18,000 USD or 67,500 SAR.

Ongoing costs primarily involve maintenance, estimated at 240 USD per year or 900 SAR per year, which may be included in the initial cost package ⁹. Additionally, the PV system provides ongoing benefits directly electricity prices and PV generation. Furthermore, certain installations may qualify for a feed-in tariff (FIT) offered by the government or electricity network, providing an additional source of financial return.

A. Return on investment

The return on investment (ROI) calculation indicates the financial benefit of that investment, this being a grid- connected PV system and it’s a percentage of the refund back over initiation cost. Annual consumption and PV energy production = 54 MWh/Year. shown in Figure 8.

B. Pay Back Benefits

A high ROI means that the gains are high compared with the investment costs. The ROI can be calculated using the life cycle cost and life cycle income of the system which is shown as 2592 USD = 9720 SAR annual savings. Refund back is Initiation cost over annual price for energy production and it’s after 7.2 years.

Energy Production of 25 years (Wh) = Annual Energy

Production (Wh) × Number of years × Efficiency (3)

We have energy production of 25 years = 54 MWh × 25×0.84 = 1.134 GWh

With annual Raise 3% of (fit) = 3%

The Total Raise in 25 Years of (fit) (%) = Annual Raise (%) × Number of Years (4)

With Total Raise in 25 years of (fit) = 3% × 25 = 75 %

Total Cost Saving Over 25 Years = Energy Production of 25 years (GWh) × Tariff (GW/h) × Total Raise (5)

Total Cost Saving Over 25 Years = 1.134 × 18000 × 1.75 =357.210 K SAR

Total Saving % Over 25 years = Total Cost Saving / Initial System Cost (6)

Total Saving % Over 25 Years = 357.210 K / 67.5 K = 529.2 %

Conclusion

This study investigated the design and performance of a grid-connected PV system for EV charging. The system utilizes 48 PV panels arranged in four parallel strings of 12 series panels each. A 25 kVA Huawei inverter converts the generated DC power to 24.3 kW AC, supplying the EV charger. A net metering system tracks both imported and exported energy, balancing the customer's needs by recording active and reactive energy in both directions. The proposed system provides the user with the ability to power their EV using solar energy. Design software (PVsyst, SketchUp, and AutoCAD) was used to create the architectural design, shading analysis, and electrical wiring diagram, including connection points and protection devices. Power consumption calculations for the EV were performed to ensure sufficient power supply from the PV system. Preliminary results indicate that the solar station can potentially generate 54 MW annually, resulting in cost savings of 9,375 K SAR and a return on investment (ROI) of 529.2%. The payback period is estimated at 7.2 years.

References