integrated onboard charger

An integrated onboard charger (OBC) that functions as a boost converter is a modern design strategy used in electric vehicles (EVs)

What Is an Integrated OBC?

An integrated OBC combines the traction inverter and motor windings to act as part of the charger during grid charging, avoiding the need for a standalone charger. One of its modes is boost operation, where it steps up the AC line input voltage to the required battery voltage.

✅ When It Works as a Boost Converter

• In AC charging mode, the grid AC is rectified, and the existing motor windings and inverter are configured to act as a boost inductor and switch.
• This topology is often used for single-phase AC input (230 V) to charge high-voltage EV batteries (e.g., 400–800 V DC).

⚙️ Boost Mode Functionality

Simplified Process:

1. AC Input (grid) is connected to the motor terminals via relays/contactors.
2. The inverter bridge switches are configured to operate in boost mode.
3. The motor windings act as the inductors.
4. The battery acts as the DC output of the boost converter.

🧰 Simulink Implementation: Key Elements

🔩 Required Components:

BlockFunction

AC Voltage SourceSimulate grid input

Diode Bridge or Universal BridgeAC-DC rectification

InductanceModel motor windings

MOSFET/IGBT + PWMUsed as boost switch

BatteryDC output/load

Control LogicClosed-loop control for voltage regulation

PowerguiRequired for simulation

🧠 Control Strategy

• Sense battery voltage
• Use a PI controller to regulate the duty cycle
• Control PWM to switch IGBT/MOSFET
• Achieve desired output (battery) voltage