Electric Vehicles as Powerhouses: The Bidirectional OBC Breakthrough

The On Board Charger is a critical component that consists of a power circuit, which may include Power Factor Correction (PFC) and a phase-shifted full bridge or a LLC resonant converter, and a control circuit.

What is bidirectional OBC? How does it work?

The On-Board Charger (OBC) in new energy vehicles is categorized into two types: unidirectional and bidirectional.

The unidirectional OBC is designed to transform the alternating current (AC) voltage from the power grid into direct current (DC) voltage, which is then used to charge the vehicle's battery pack. On the other hand, the bidirectional OBC has the additional capability to convert the DC power stored in the battery pack back into AC power, which can be fed back into the grid or used for other applications.

What is the use of OBC's bidirectional function?

Bidirectional charging technology enables a two-way flow of power – not just charging your car, but also discharging it. But where does the energy head when it exits your vehicle?

V2G - Vehicle to Grid

V2G is the process where an electric vehicle (EV) with a bidirectional charger sends electricity from its battery back to the power grid, using a built-in DC-to-AC conversion system. This smart charging mechanism can help regulate energy supply and demand, allowing EVs to draw power during off-peak hours and contribute to the grid during peak demand. It's an efficient strategy considering that vehicles are parked about 95% of the time. With the right setup, these parked EVs could act as mobile power banks, offering a stabilizing force for future power grids. In essence, we can envision EVs as rolling energy storage units, ensuring a constant supply of energy for everyone.

Image source: Toka charging

For an extended period, concerns over driving range and the availability of charging infrastructure have been significant barriers to the widespread adoption of electric vehicles (EVs). Although advancements in battery technology by manufacturers have demonstrated increased range capabilities, and the proliferation of charging stations has alleviated some of these concerns, the challenge of efficient EV charging remains. This challenge, however, also presents an opportunity to enhance the balance and efficiency of the power grid's load.

An OBC with bidirectional energy transfer capabilities can draw power from the grid for charging and also return excess energy back to the grid, thereby contributing to the stabilization of a city's overall power infrastructure.

V2H - Vehicle to Home

V2H is the practice of using an EV's bidirectional charger to deliver electricity from the car's battery to residential or commercial buildings, also facilitated by a DC-to-AC converter within the charger. Similar to V2G, V2H can contribute to balancing energy supply and demand on a larger scale. For example, by charging your EV overnight when demand is low and then using that stored energy during the day, you can help decrease peak-time consumption and alleviate stress on the grid. V2H ensures that homes have a reliable power source when it's most needed, thus reducing the overall strain on the electricity grid.

Image source: gridx

As we progress towards a fully renewable energy landscape, both V2G and V2H will become increasingly significant. Renewable energy sources like solar and wind are intermittent, generating varying amounts of power based on time and conditions. Bidirectional charging allows EVs to maximize their battery storage potential, benefiting the entire energy ecosystem and the environment. In this context, EVs can serve as a renewable energy buffer: absorbing and storing surplus solar or wind energy for later use during periods of high demand or low production.

In summary, bidirectional charging with V2G and V2H not only enhances the functionality of EVs but also plays a pivotal role in creating a more sustainable and resilient energy infrastructure.

What are the benefits of OBC's bidirectional function to the electric vehicle battery?

Bidirectional charging is also advantageous for the health of the vehicle's battery. It is like the practice of occasionally discharging and then fully charging a smartphone battery to prolong its life. Continuously keeping a battery at a high charge level can stress the components and reduce their lifespan, leading to the need for premature battery replacement, which is costly.

In an ideal scenario, the OBC should be equipped with smart sensing capabilities that can detect when the vehicle's battery level is low, such as at 30%, and then initiate a battery cycle by feeding the excess energy back into the home grid, followed by recharging the vehicle. This process helps to maintain the battery's health and prolong its life. The primary objective of employing a bidirectional OBC is to facilitate an efficient transfer of power with minimal energy loss during the transmission process. This efficiency is crucial for both the vehicle's operational costs and the overall sustainability of the power grid.

Brogen's Bidirectional OBC

Main Specifications

Project	Rated Output Power	Input Voltage Range	The Output Voltage	Maximum Output Current	Voltage Stabilization Accuracy
AC/DC	6.6KW	90~264Vac	210~450Vdc	20A	≤±1%
VTL	3.3KVA	250~450Vdc	220Vac±15%	16A	≤±5%
DC/DC	2.5KW	200~450Vdc	14.5V±0.25V	173A	≤±1%

Should you want to know more about our bidirectional on-board charger, please feel free to contact us via inquiry@brogenmotors.com. We promise to get back to you within two business days.

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We've forged strategic alliances with key players in the new energy vehicle sector, including electric motor and controller manufacturers, battery pack producers, and charging station suppliers. We also collaborate with suppliers of essential components such as EV car battery, electric vehicle motor(PMSM motor), motor controller, OBC+DCDC+PDU, axial flux motor, BMS, air conditioning systems, air compressors, and power steering systems.

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