Design and Hardware Implementation of Bidirectional Power Converter For Vehicle Grid Integration
Electric Vehicles are becoming an emerging trend and will eventually penetrate in the power systems via distribution grids. Therefore, there must be an accurate efficient control strategy which can lead to smooth, promising and reliable bi-directional power flow. The EV battery charger must provide
2025-06-28 16:26:23 - Adil Khan
Design and Hardware Implementation of Bidirectional Power Converter For Vehicle Grid Integration
Project Area of Specialization Electrical/Electronic EngineeringProject SummaryElectric Vehicles are becoming an emerging trend and will eventually penetrate in the power systems via distribution grids. Therefore, there must be an accurate efficient control strategy which can lead to smooth, promising and reliable bi-directional power flow. The EV battery charger must provide bi-directional power to charge EV battery and also provide power to grid during peak hours. Since V2G or G2V technology is an emerging trend in the modern power systems.
In the upcoming era, the power systems will transition from electricity consumption to electricity utilization in which the consumers will be actively participating in giving the surplus electric power back to the grid and doing a bidirectional trade. This will enable consumers to utilize electric power in the most efficient way possible. EVs will be an important part of that power system. EVs are penetrating in the national grids at distribution generation (DG) level, it is very essential to balance the grid at the peak time. Thus, the efficient bidirectional power converters are essential to implement V2G & G2V technology.
We want to use renewable energy but renewable energy is intermittent power source and the fluctuations might occur at the grid like voltage and frequency.
Project ObjectivesFocused on the rational utilization of large-scale electric vehicle energy storage medium, the bidirectional and efficient power converter technique is important for the vehicle-to-grid (V2G) system. Designing a bi-directional charger of electrical vehicle including its integration with the grid in order to utilize the surplus energy and reduce consumer cost.
Core aim of getting into the concept of bi-directional flow of power is the improved and efficient power transfer. Because the main objective is to design a system which is capable enough to work according to the designed parameters.
We can get an understanding of bi-directional working by considering how charging an electric vehicle works. When you plug in your car, it takes AC from the Grid (V2G), which is then converted into a DC by the internal charger or converter before being stored in the battery.
To bring out energy from the battery, you need a bi-directional charger that will convert the DC from the battery into AC before sending it back to the grid (G2V).
Integration with grid is a tedious job, due to variations in various parameter i.e. frequency, voltage, phase difference etc.
Project Implementation MethodThis project basically consists of two stages: AC-DC conversion for Grid to Vehicle integration to provide the surplus energy back to grid and DC-DC conversion for Vehicle and battery integration for battery charging.
The full-bridge AC-DC bidirectional converter operates as inverter with sinusoidal current and unitary power factor, and the reversible DC-DC converter operates as a boost converter. As in the G2V operation mode and in the V2G mode the full-bridge AC-DC bidirectional converter must be synchronized with the power grid fundamental voltage.
The bidirectional power converter basically works in two modules:
1): - Control Circuit which consists of a Gate driver IC use to generate PWM (Pulse Width Modulation) to drive the gate of MOSFET.
2): - Power Circuit which is the main circuit for bi-directional conversion, in case of DC-DC conversion we have used the DAB (converter topology) and in case of AC-DC conversion simple capacitor is used and the technique of APWM (Advanced Pulse Width Modulation) is adopted to drive the MOSFETs.
These circuits are analyzed through simulations in order to derive required results by varying different parameters and values of RLC components. The converter is then to be designed or implemented practically to compare the calculated/measured and the practical values.
Benefits of the ProjectVehicle-to-Grid (V2G) or Grid-to-Vehicle (G2V), bi-directional charging is the ability of an electric vehicle to reverse the process of taking power from the grid, i.e. the vehicle can supply energy back to the grid.
Basic advantage of approaching the bi-directional flow is that in case of bidirectional flow of power the grid is not the only source that can draw power from an electric vehicle’s battery but the energy can power a home, another electric car, power tools, etc.
Save money – Benefitting from flexible energy prices
If the charging time of the vehicle is linked to the energy prices, we can charge the battery cheaply and when the energy prices increase again, we can use the energy from the vehicle battery to reduce the energy costs.
Thereby the owner of a bi-directional charging vehicle and bi-directional charging station gains independence from energy providers.
Reducing the load of the grid
With lots and lots of bidirectional charging vehicles, the grid can benefit from a mass effect. The load of the grid can be reduced for peak hours, such as 4 pm-8 pm, when workers and students typically come home and start cooking or using other electrical devices. With many bi-directional charging vehicles connected to the grid, this peak load can be reduced for the grid. Consequently, the risk of grid outages can be reduced for all.
Use of wind-power and solar-power
For wind and solar power, power generation is highly dependent on daily conditions. Having many bi-directional charging vehicles connected to the grid, the vehicles can be charged when the weather conditions allow for a high power generation. If the weather conditions change and the power for the grid needs to be generated by other technologies, the vehicles can support the grid while starting up the other power plants.
Powering homes during extreme weather conditions
With climate change, many regions experience more extreme weather conditions. Hard snowfalls or extreme Winds can lead to power lines collapsing. One example of this was the extreme weather condition in Pakistan during floods. With the grid broken down, many customers were stuck with flexible energy prices skyrocketing.
Technical Details of Final DeliverableThe core aim of this project to design power converter system that implements bidirectional flow between the grid and an electric vehicle battery, where a dual active bridge is advantageous. With a bidirectional topology and proper control all the major grid constraints, such as power quality, harmonic rejection, active and reactive power control, and others, can be easily satisfied. A hardware prototype of the power converter is built. Moreover, its integration with grid is also target to be achieved.
Reasons for selecting DAB (Dual Active Bridge) as DC-DC converter
DAB dual active bridge topology is selected on basis of its efficiency and reliability, modularity and symmetrical structure in the DAB which allows the converters to achieve high power throughout and facilitate a bidirectional mode of power flow.
DAB also provide high efficiency with advanced phase shift modulation control. DAB has advantage of using Wide battery voltage range enabled by single shift modulation control.
Increased power density by higher switching frequency through smaller magnetics. DAB basically act as main circuitry of DC to DC conversion. The Dual Active Bridge is a topology with two active semiconductor bridges (Full Bridges) and a High Frequency Transformer (HFT).
Final Deliverable of the Project Hardware SystemCore Industry Energy Other IndustriesCore Technology Clean TechOther TechnologiesSustainable Development Goals Affordable and Clean Energy, Sustainable Cities and Communities, Responsible Consumption and Production, Climate ActionRequired Resources| Item Name | Type | No. of Units | Per Unit Cost (in Rs) | Total (in Rs) |
|---|---|---|---|---|
| Total in (Rs) | 80000 | |||
| Power MOSFET | Equipment | 20 | 450 | 9000 |
| Bread Board | Equipment | 5 | 200 | 1000 |
| Gate Driver IC's | Equipment | 20 | 150 | 3000 |
| High Frequency Transformer | Equipment | 2 | 6000 | 12000 |
| Phase Detector IC's | Equipment | 3 | 300 | 900 |
| Capacitors, Resistors | Equipment | 40 | 25 | 1000 |
| Relay's | Equipment | 4 | 280 | 1120 |
| ACS712 Sensor | Equipment | 5 | 350 | 1750 |
| Toroidal Inductor Magnetic inductance Coil | Equipment | 5 | 700 | 3500 |
| Winding Wire | Equipment | 1 | 1000 | 1000 |
| F28379D LaunchPad development kit | Equipment | 1 | 15750 | 15750 |
| PCB Fabrication | Equipment | 1 | 15000 | 15000 |
| Batteries | Equipment | 2 | 2000 | 4000 |
| Connecting Wires | Equipment | 10 | 50 | 500 |
| IC Sockets Base | Equipment | 25 | 8 | 200 |
| Veroboard | Equipment | 2 | 140 | 280 |
| Charging station body | Miscellaneous | 1 | 8000 | 8000 |
| Stationery (Printing) | Miscellaneous | 1 | 2000 | 2000 |