A brief note on the vehicle control unit

A Vehicle Control Unit or VCU plays a crucial role in managing various aspects of the vehicle’s performance, functionality, and safety. Poorvak Kapoor, AVP, Vehicle Intelligence, Euler Motors, pens a note on the basics of VCU.

A Vehicle Control Unit is an electronic control unit that manages a vehicle’s subsystems. A VCUs’ responsibility is usually to interact, aggregate data, and then make decisions. It interacts with different ECUs (Electronic Control Units) within a vehicle ecosystem. These different ECUs would ideally involve components like Motor Controller (MCU), Battery Management System (BMS), On Board Charger (OBC), DCDC, Instrument Cluster (IC), and Telemetry Control Unit (TCU).

Image source: Euler Motors

The VCU communicates with these ECUs using various communication protocols such as CAN, LIN, and Ethernet. All ECUs within the vehicle are responsible for maintaining the health status of their respective components and reporting it to the VCU. Henceforth, VCU marks the vehicle healthy and operational – from an electronics and mechanical standpoint. Modern VCUs require reliable and high-speed communication with powertrain controllers and intelligent and robust control of the vehicle powertrain to coordinate driving modes. The VCU ensures that the vehicle operates efficiently and safely by monitoring critical systems such as battery health, motor temperature, and the state of charge.

VCU function in an electric vehicle

In an electric vehicle, the VCU regulates and optimizes the power flow between the battery and the motor. It also monitors and controls other systems, such as the regenerative braking system and the charging system. It receives signals from various sensors in the vehicle and uses that information to control the power train system. For example, when the driver presses the accelerator, the VCU receives a signal from the pedal position sensor and sends a signal to the motor controller to increase the power output to the electric motor. Or when the driver presses the brake, the VCU sends a signal to the motor controller to reduce the power output and engage the regenerative braking system to slow down the vehicle.

Types and applications

There are different kinds of VCUs available, and the choice depends on the vehicle’s application and requirements. For an electric L5 vehicle (like the Euler HiLoad EV) meant for cargo application, an advanced VCU with high processing power and the ability to integrate with other systems is more suitable. One must analyse EV operation parameters vis-a-vis road conditions and other criteria to ensure that control unit designs are robust and adaptive, enabling system improvement in dynamic and steady-state performance. At Euler, we have designed our VCU to guarantee superior control strategies for charging control, high voltage coordination, and thermal management.

This article was first published in EVreporter June 2023 magazine, which can be accessed here.

Also read: Software defined vehicles and vehicle configuration management