How Do We Define A Safety Concept for a Traction Inverter?

peggy-nxp — Wed, 06 Oct 2021 22:27:35 GMT

Current Revision posted to Documents by peggy-nxp on 10/6/2021 10:27:35 PM

As car makers continue to improve each piece of the electrified powertrain, the role of the traction inverter continues to be central for energy efficient and robust EV systems. The traction inverter can make a difference in improved performance, better efficiencies and ultimately, longer driving range.

Role and Standards

The traction inverter controls energy conversion between the energy source and the mechanical shaft of the electric motor, providing acceleration, regenerative braking and switch protection. As with each safety critical component within automotive applications, the ISO 26262 functional safety standard provides recommendations for the development process of safety system products with a V cycle project management tool. The tool identifies a series of parts to address the requirements of the standard.

Defining the Concept

Developing a clear safety concept for the traction inverter is therefore essential. To achieve this, it is necessary to identify the potential hazards and limitations of the EV application. There are typically safety concerns around unintended traction or braking, as well as the risk of electric shocks. This is the first step in defining the concept.

Safety Goals, Systems and More

Along with this, the safety goals are developed and the functional safety architecture is defined. This combines hardware and software sub-element functions that are used to achieve the intended item and system functionality as well as the safety measures to protect those sub-elements.

We explain how this is applied through three simplified examples of safety architecture for EV traction systems.