Introduction
The On-Board Charger (OBC) market for electric vehicles is expected to develop at a compound annual growth rate (CAGR) of 22.4% from 2020 to 2027, reaching $10.82 billion globally. By obtaining an average 25% improvement in DC-DC rating and almost 30% reduction in charging time, Electra EV has been making significant improvements in OBC technology, thus expanding electric mobility applications and meeting end-user expectations.
What Is an On-Board Charger?
An on-board charger (OBC) is a power electronics device that charges an electric vehicle’s (EV) battery pack by converting AC power from external sources—like household plugs—into DC electricity. To identify the proper current, power, and charging standard to utilize, the OBC connects with the vehicle controller and the charging station. Several international charging standards have distinct regional requirements for China, North America, and Europe. Based on information from the vehicle controller or EV supply equipment (EVSE) controller, the OBC automatically adapts to the appropriate regional standard.
Furthermore, by enabling it to convert DC power from the high-voltage battery back to AC power, the OBC is essential to bidirectional charging. This can power AC loads (V2L), feed energy into the grid (V2G), and even charge other electric vehicles (EVs).
Enabling faster AC charging
EV manufacturers can satisfy consumer needs for faster charging while minimizing battery degradation because of advancements in OBCs. Constant voltage and constant current are the two charging modes available on AC chargers. Constant voltage, sometimes referred to as trickle charging, is slower but permits complete charging and provides more control over the battery than constant current, which charges the battery more quickly but cannot fully charge it. OBCs use constant voltage toward the conclusion of the charging process, switching from constant current at first to maximize efficiency.
Single-phase and three-phase onboard chargers are the two primary varieties. The normal capacity of a single-phase OBC is between 7.2 and 11 kW; however, a three-phase OBC can have a capacity of up to 22 kW. How quickly the car charges depends in large part on the capacity of the OBC.
The fastest option for consumers is DC fast charging, which sends direct power straight to the battery without using the OBC at all. With capacities ranging from 50 kW to 300 kW, standard DC charging stations provide more than six times the capacity of single-phase OBCs. On the other hand, three-phase OBCs’ larger capacity enables users to maximize AC charging efficiency while reducing battery wear because AC charging is kinder to batteries.
A system-level approach
Several safety features are built into onboard chargers to safeguard consumers and provide the operational safety needed for vehicle applications. These include creating a separation between external hardware and internal components to lower the chance of an electrical failure and automatically cutting off power if the load exceeds operational restrictions. Cybersecurity is especially crucial since the OBC, when connected to the EVSE controller, functions as a high-speed data gateway between the car and the grid.
From the inlet to the battery. One such product is a three-phase On-Board charger that satisfies numerous automotive-grade data and charging requirements, including the Home Plug, V2G, and ISO 26262 functional safety standards.
To provide cutting-edge, integrated grid-to-battery-pack charging systems that satisfy the strictest performance, safety, cybersecurity, and power criteria.
Role of On-Board Charger
Controlling the flow of electricity from the grid to the vehicle’s traction battery is the main goal of an onboard charger (OBC), which enables electric vehicles to be charged from any power source. Consequently, depending exclusively on charging facilities is no longer necessary.
When charging a battery, the OBC also regulates the voltage and current levels. Constant voltage and constant current are the two basic forms of charging. Because there is a chance of overcharging, constant current charging might cause battery degradation even though it delivers great efficiency and rapid charging. Conversely, continuous voltage charging can cause a spike in current to first enter the battery.
To solve these problems, the battery is usually charged with constant voltage initially, shifting to constant current after an established charge level is reached. The most important purpose of an electric vehicle’s onboard charger is this charging approach.
Role of OBC in AC Charging
The Battery Management System (BMS) uses the On-Board Charger (OBC) to charge the battery during AC Level 1 and Level 2 charging. The OBC transforms grid AC electricity into DC power. The OBC is in charge of controlling the voltage and current during the charging process. The power output of AC charging does, however, reduce with increasing charging time.
Role of OBC in DC Charging
In DC fast charging (Level 3), the charger converts AC to DC and supplies it directly to the battery, eliminating the need for an onboard charger. This reduces charging time. The EVSE is organized into stacks to deliver high current, as a single stack cannot provide the necessary power. Therefore, the OBC has no role in DC charging.
Types of On-board Chargers
EV on-board chargers come in two primary varieties:
- On-board single-phase charger
- On-board charger in three phases
This classification is based on how many phases the charger can use. A three-phase OBC can generate up to 22 kWh, while a single-phase OBC typically produces between 7.2 and 7.4 kWh. It is possible for the OBC to automatically identify the kind of input it is connected to. When operating in a single phase, the charger can handle 110-260V AC; when operating in three phases, it can manage 360-440V AC. The output voltage applied to the battery is between 450 and 850 volts.
Working on an Onboard Charger
Design Considerations for OBCs
Key factors to consider when designing onboard chargers (OBCs) include:
1. The suitable output levels and the AC input
2. The battery pack’s maximum power capacity
3. Minimizing space and maximizing cooling
4. Charging time requirements
5. Power Factor Correction (PFC) and AC signal rectification
6. Connection of the EVSE with the EV
7. Ensure that the battery and power source are safely isolated.
Benefits of On-Board Charger
Enhancing Charging Efficiency
Reducing the time required to recharge an electric car by maximizing charging efficiency is one of the main objectives of the onboard charger. On-board chargers reduce energy loss and maximize charging speeds by efficiently converting AC power from the charging station into DC power for the battery. EV owners drive longer with zero emissions and spend less time charging.
Adaptive Charging Technologies
Adaptive charging technologies are widely used by modern on-board chargers to increase efficiency. Onboard chargers dynamically adjust to voltage, temperature, and battery state, optimizing charging in real time for efficiency and longevity.
Conclusion:
In conclusion, the onboard charger plays a crucial role in optimizing electric vehicle charging efficiency. Moreover, it ensures seamless energy conversion, enhancing overall performance. Therefore, its integration is vital for improving charging speed and reliability. Onboard chargers efficiently convert AC to DC power, minimizing energy loss and boosting charging speed. Advances in adaptive charging and EV technology will drive future innovations for a sustainable transition.
Explore our selection of VCU add-ons, which include CAN Keypads, CAN Displays, and EV Software Services. These manufacturers make these products to improve performance, visibility, and control for smooth EV operation.