Optimise Electrical Vehicle Systems with Simulation

Shitalkumar Joshi

Shitalkumar Joshi

30 Jun 2021
09:00 AM
4 Min Read

With the kind of transformation electrification is bringing about, adoption of new product development methodologies and their effective utilisation will define the future of mobility.


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Transportation drives the global economy. It’s at the heart of both business and pleasure. With the world's population nearing eight billion, all that travel adds up and is taking a toll on the planet. 

There has been a strong need to find mobility solutions with lower environmental impact. The automotive industry is experiencing the challenge of simultaneously addressing the needs of new technology introduction along with new product development. To meet this challenge, the global automotive industry is undergoing a period of dramatic technology transformation. 

While traditional vehicles are expected to be highly energy-efficient ones, disruptive trends like electrification continue to alter the companies, industry and consumers. Emerging non-traditional players and traditional automotive companies are adapting to stay relevant at an unprecedented speed. 

Engineering teams must now combine speed with a strong commitment to deliver the product promise of reliability and performance. To support the same, the industry is witnessing innovation in the traditional product development processes. 

Some of the major trends in the transformation of product development process include:

Rapid prototyping through Model Based System Engineering (MBSE)

MBSE is the formalised application of modelling used to support system requirements, system and component design, analysis, verification, and validation activities throughout the product life cycle. 

MBSE is a well-established practice for software development across the industries, but its application for the physical asset development has been limited. However, the increasing complexity of the systems and ever-increasing role of the software in physical system operation is calling for a transformation in combined software and hardware development practices through MBSE. 

The ideal orchestration of MBSE can be extremely powerful, where digital continuity links all stages of product development, from requirement to validation. This ultimately enables an early-stage detection of problems and correction. However, such implementation can be a significant undertaking panning over several years.

Even though complete MBSE implementation is still a distant dream, there are elements of it being adopted by industry. Rapid prototyping approaches are being used to validate the design architecture right at the inception using historical design information. This helps to remove early-stage uncertainties and reduce design iterations. Model Based Design is employed to validate concept level designs without significant time investment. The next frontier for MBSE adoption will be virtual validation. 

Virtual validation: integrating hardware (through physics-based models) and software 

Moving the verification and validation practices to a virtual environment is gaining a lot of traction in the automotive industry. Currently, 40% of the product development cost is spent in integration and validation. Of this, about 90% is done using physical testing. Virtualisation in this segment can result in significant savings in terms of cost and time.

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Various stages of testing and validation that are practiced in the industry.

The above image shows the various stages of testing and validation that are practiced in the industry. The areas marked in green have a great potential for increased virtualisation. The industry is moving towards testing validations to increased virtual environment using high-fidelity simulation models.

The feasibility of developing a virtual validation framework for electric vehicles is much better compared to IC engines as it is possible to develop accurate predictive models using FEA or CFD simulation for EV components. Companies are looking at reusing the component intelligence developed through physics-based simulation and utilising it in system simulation. 

The behavioural model generated from thermal management analysis of the battery is being converted to a Reduced Order Model (ROM) to be used as a battery plant model. The models developed using this method are being used for system performance prediction as well as BMS validation. 

Similarly, electromagnetic simulations from motor are being applied for validating and tuning motor controls. A further abstraction of these models can make them directly usable for system performance calculation.

An even more exciting prospect is the ability to conduct the virtual drive test. The high-fidelity system model developed using the above practices can be connected to a driving simulator. The driving simulator can account for a real-life road scenario such as road elevation, traffic, city/highway driving etc. 

This brings the model predicted results much closer to real life. Considering the tens of thousands of scenarios that need to be validated for vehicle sign-off, the virtualisation of the drive test can result in significant cost reduction and design efficiency.

Process Integration and Design Optimisation (PIDO)

The goal of CAE-based optimisation in virtual prototyping is to achieve optimal product performance with minimal usage of resources and a high degree of reliability. These competing goals require the inclusion of Robust Design Optimisation (RDO) in product development process. 

However, when the design optimisation practices are applied together with virtualisation practices mentioned above, the optimisation goals can be elevated to system performance goals, requirement validations and trade studies. 

The current design practices, however, involve heterogeneous tools from different physics, fidelity, in-house methods and commercial tools like Excel, Python codes and Ansys. These environments need to be integrated to develop the design workflows that are repeatable, automated and seamless. PIDO enables substantial productivity gain by capturing the simulation best practices as a standard workflow and allows optimisation on component, sub-system as well as system level.

In summary, PIDO provides a comprehensive integrated platform that ensures robust design optimisation in most consistent way throughout the organisation. 

Modelling and simulation to meet compliance

Today’s vehicles give unprecedented control to machines; hence safety measures need to be multiplied. 

Functional Safety:

Automotive design engineers for electrification and autonomous are expected to implement key safety analysis methods like Hazard and Operability (HAZOP) analysis, Fault Tree Analysis (FTA), Failure Modes and Effects Analysis (FMEA). The industry is now moving with integrated software development and functional safety tools. They are specifically tailored to domain-specific standards like ISO 26262 and can be applied in all phases.

EMI-EMC:

The increasing role of electronics in automotive is making EMI compliant design challenging. Electrified powertrains, sensors, auxiliary electronics and sophisticated infotainment systems pose complex interaction of electromagnetic waves at all frequencies from KHz to GHz. 

Prediction/ rectification of electromagnetic interference, which was done mainly through trial-and-error method earlier, is now done through EM simulations. In what is called EMI aware design method, simulations are used as pre-compliance tool. Simulation and modelling will make EMI certification an easily tractable challenge.

Conclusion 

Electrification is bringing about a transformation like never before in the last 150 years. An equal transformation in the product development process will help organisations survive and grow in the wave of disruption. The adoption of new product development methodologies and their effective utilisation will define the future of mobility.

About the Author: Shitalkumar Joshi is Technical Director, Electrical and Electronics – India at Ansys.

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