Proposed solution for the electrification of a motor vehicle formerly powered by an internal combustion engine (case study: Oltcit)

A vehicle powered by electricity is a kind of alternative fuel-powered automobile that uses electrically powered engines and controllers for them in place of a conventional internal combustion engine. Instead of burning a carbon-based fuel, power is generated using battery packs. This not only results in monetary savings but also has an extremely reduced negative influence on the surrounding natural environment. The high price that a buyer must pay to get one of the electric cars that are now on the market is one disadvantage. In this article, we explore the possibility of developing an electric vehicle with the use of an electrical conversion kit. The fundamentals and constituent parts of electric car systems will be broken down, and the procedure for transitioning from an internal combustion engine vehicle to an electric vehicle will be analyzed in this paper.


Introduction
The widespread perception that oil is a resource that will be almost depleted within the next halfcentury is one of the primary factors contributing to the ever-increasing cost of a barrel of oil [1].Electric vehicles and hybrid electric vehicles, which major manufacturers are now proposing, indicate a shift in the transportation paradigm for cities.In addition, a number of organizations and energy experts are proposing new regulations that will stimulate research, development, and demonstration projects aimed at boosting electric vehicles.
On the other hand, low-cost solutions that make use of dependable components that are already on the market might also be presented [2,3].Consequently, the transformation of cars powered by internal combustion engines into electric vehicles is an appealing option for the interim time of coexistence.
Electric vehicle conversion is the term used to describe this procedure the transformation procedure [4].This is a difficult procedure from an engineering standpoint, and it requires understanding of multiple domains and mainly in mechanics but also the electronics domain is important to complete.The electric motor and its associated controller, an energy storage system, and its associated charging system are the primary systems that need to be integrated.
Batteries are the option that has been suggested the most often for the energy storage system.As a result, a mechanism for charging the batteries is required as well.The use of static power converters IOP Publishing doi:10.1088/1757-899X/1303/1/012012 2 has historically been the technology of choice for the implementation of battery charging systems, but there are a variety of topologies that also may be employed [5,6].Because of this different charging algorithms will need to be utilized in order so that charging technology behind batteries will work.
Charging systems for batteries may also be used to convert electric vehicles and hybrid vehicles into an energy storage system [7].This system both receives and distributes energy, which contributes to the stability of the power grid.Therefore, in addition to the process of charging batteries, the flow of energy may also occur in the other direction, depending on the features of the power grid and the advantages gained by the driver.
This article, discusses the process of converting an internal combustion engine vehicle into an electric vehicle [8].All of the essential components, including the powertrain power electronics converter and the battery charging system, has their designs and prototype implementations described.

Electric vehicle development steps
This build started off with a manual OLTCIT 11R vehicle, which can be seen in the figure 1 bellow.We decided to go with this vehicle because it was readily accessible, its bed provided a convenient spot for us to store batteries, and its manual gearbox makes it possible for us to more easily convert it to one with an electric engine.
Based on the weight of the vehicle, the weight of the planned electrical components, dimensions, and the intended range, we were able to determine the amount of power that would be necessary to achieve a variety of possible peak speeds as well as the range that would be associated with each of those speeds.The electric vehicle design was calibrated in three stages:  Electric traction motor (ME), which is of the PMSM type (permanent magnet synchronous motor)  Command and control system (SCC), which consists of the BorgWarner -Sevcon Gen. 4 unit and the start/stop components  Energy storage system (SSE), which consists of 6 12V Pb batteries/accumulators, providing a total voltage of 72 V.

Electric traction motor
The electric traction motor is a three-phase permanent magnet synchronous motor (PMSM) with 10 poles, 8000 rpm, and a nominal power of 13 kW (rated current of 157 A).
However, the electric traction motor is capable of assuring a peak output of around 48 kW for approximately 1 minute maximum (at a current of max.600 A).This peak output is crucial for accelerating the vehicle quickly, especially during overtaking or merging vehicle flow.Beyond this one-minute period, the motor's output gradually decreases to avoid overheating and potential damage.Nonetheless, the electric traction motor provides sufficient power for regular driving conditions and ensures a smooth and efficient performance of the electric vehicle.
The ME1905 electric motor is produced by Motenergy, its overall dimensions being given as follows in the figure 2: The operating curves of the motor (input power, output power, voltage, current, efficiency) are shown in the following figure 3. The input power curve shows the amount of power supplied to the motor, while the output power curve represents the power produced by the motor.The voltage and current curves depict the electrical characteristics of the motor, showcasing how these values change with varying load conditions.Lastly, the efficiency curve illustrates the motor's ability to convert input power into useful output power, providing insights into its overall performance.Together, these curves offer a comprehensive understanding of the motor's behavior under different operating conditions.As can be seen, the output power of the motor is around 7 kW, and the current draw is approximately 100 Amperes, when the supply voltage is 72 Volts, which is the nominal voltage of the battery pack that is being utilized.The torque is around 22 Nm, which is adequate torque for an Oltcit car to operate.
Controlling the position of the motor is accomplished by use of a sinusoidal encoder, also known as a sin/basket encoder, which is connected to the Sevcon command and control system.

Command and control system
The command-and-control system (SCC) is produced by BorgWarner, being a Sevcon Gen. 4 system, see figure 4. It is a highly advanced and efficient system designed for electric vehicles.The SCC seamlessly integrates with the vehicle's drivetrain, providing precise control over power delivery and optimizing overall performance.With its cutting-edge technology, the SCC ensures smooth acceleration, regenerative braking, and enhanced energy management, making it a reliable choice for electric vehicle manufacturers.The Sevcon has two parts, a low-voltage one for command and control, and a high-voltage one, which is responsible for powering the three-phase electric traction motor.Three-phase voltage is obtained by means of an inverter built into the SCC.The command-and-control part is interfaced through a 35-pin Ampseal jack.This allows for easy connection and disconnection of the Sevcon with other electrical systems.The high-voltage section, on the other hand, is connected directly to the motor through heavy-duty cables.By separating the command-and-control functions from the power delivery, the Sevcon ensures efficient and safe operation of the electric traction motor, making it an essential component in electric vehicle technology.

Energy storage system
The battery system (SSE) consists of 6 Varta batteries with Pb, AGM type, capable of providing a maximum current of 680 amperes.The rated voltage is 12 V, and the capacity of one battery is 60 Ah.The 6 batteries inserted will provide a voltage of 72 V.This battery system is commonly used in largescale applications such as backup power systems for commercial buildings or renewable energy storage systems.With a maximum current of 680 amperes, it can support high-power devices and equipment.The capacity of 60 Ah per battery ensures a long-lasting and reliable power supply, while the combined voltage of 72 V allows for efficient energy distribution.

Connections and testing of the EV
The battery pack is directly connected to the Sevcon command and control system, the positive terminal of the package having a 500 A fuse embedded in the SCC structure.The delimitation of the force part from the control part is done by means of a power contactor, the control of this contactor being made in low voltage.On the power/control side of the contactor (powered at low voltage from SCC Sevcon) there is a 5 A protective fuse, emergency stop button and key contact that activates the force part of the contactor.The emergency stop button and key contact provide an additional layer of safety by allowing immediate shutdown of the force part of the contactor in case of any unforeseen circumstances.When activated, the force part of the contactor allows the flow of high voltage power from the SCC Sevcon to the connected system.This setup ensures that the control of the contactor is securely separated from the high voltage power, preventing any accidental or unauthorized activation.
Furthermore, the emergency stop button and key contact are strategically placed in easily accessible locations, ensuring that they can be quickly and effortlessly reached in case of an emergency.The emergency stop button is designed to be highly visible and easily identifiable, with a bright red color and a prominent label.This ensures that anyone in the vicinity can immediately recognize and activate it in the event of a hazardous situation.Additionally, the key contact adds an extra layer of security by requiring a physical key to be inserted and turned in order to activate or deactivate the force part of the contactor.The Sevcon controller is programed using BorgWarner DTV software.With the BorgWarner DTV software, users can easily adjust parameters such as acceleration, deceleration, and torque settings to optimize the performance of the Sevcon controller.Additionally, the software provides real-time data analysis and diagnostic tools, enabling efficient troubleshooting and maintenance of the controller.Overall, the integration of BorgWarner DTV software enhances the functionality and reliability of the Sevcon controller in various applications.
The general schematic for the EV connections can be seen in the figure 8.It is important to mention that the schematic for EV connections may vary depending on the specific model or manufacturer, so it may not be accurate to say that this is a general schematic that applies to all EVs.Further more the entire electrical drive can be seen in figure 9, installed on the vehicle.

Conclusion
The conversion process involved removing the engine and fuel system and replacing them with an electric motor and battery pack.The paper also discussed the challenges encountered during the conversion, including modifying the vehicle's wiring and ensuring compatibility with existing systems.Overall, the successful conversion demonstrated the feasibility of transforming conventional vehicles into electric ones, highlighting the potential for reducing emissions and dependence on fossil fuels.
The paper conversion proved that as these technologies continue to evolve, the process of converting vehicles to electric power will become even more efficient and cost-effective.Furthermore, the integration of smart charging systems and renewable energy sources, such as solar panels, were identified as potential enhancements to further reduce the environmental impact of electric vehicle conversions.
Additionally, it is crucial to address any potential challenges and barriers that may hinder the transition, such as limited range and charging time.By addressing these issues and investing in research and development, the potential for electric vehicle conversions to revolutionize transportation and reduce greenhouse gas emissions is immense.
In conclusion, the paper emphasized the importance of continued research and development in the field of electric vehicle conversions to accelerate the transition towards sustainable transportation.

Figure 6 .
Figure 6.On/off command for the EV.Figure 7. Safety fuse.

Figure 7 .
Figure 6.On/off command for the EV.Figure 7. Safety fuse.

Figure 9 .
Figure 9. Electrical drive installed on the vehicle