By Eric Cohen, Marketing Manager
Virtual reality is making its way into everyday life, providing life-like experiences through computer simulation. Computer simulation is also essential for developing safe and effective wireless charging systems for everyday life.
At WiTricity, our 15 years of scientific research and engineering development have proven that wireless charging is more than just wireless power transfer. Computer simulation is key to ensuring all aspects of our wireless charging system work optimally and are safe for humans. Our team has a deep scientific understanding of the behavior of each sub-system and component of our wireless charging solution. But, to ensure the best product performance, stability, and safety – before any component is built and tested – simulations are performed that allow us to evaluate different materials or configurations and see the impact those changes have on the performance of the system. Computer simulation under different sets of assumptions and conditions enables us to build the product and go into field testing with a high level of confidence in how our product will behave.
Through 15 years of creating computer simulations of our electromagnetic systems and then comparing the simulation results to lab tests of the actual components, we have improved the accuracy of the simulations and our practical understanding of the electromagnetics. By making design tradeoffs virtually, rather than experimentally, we’re able to rapidly tune our designs to get better real-world behavior. Each tweak along the way makes WiTricity’s wireless charging system better. And better.
But what are we simulating?
Every aspect of the wireless charging platform is evaluated using custom computer simulations built on many years of experience. We simulate performance of the electronic circuits in the system using typical circuit simulations tools, such as SPICE (Simulation Program with Integrated Circuit Emphasis), modeling how the different electronic components and circuits behave in our designs. We also utilize finite element thermal simulations to ensure that mechanical structures and electronic circuits operate within allowed temperature ranges. In addition, control system simulations are utilized to understand how the system behaves dynamically to ensure stability in all operating modes.
For WiTricity, simulations of the electromagnetic fields that couple the charging pad on the ground and the vehicle are especially important. We evaluate the magnetic fields created by the coils to predict energy transfer performance, but we also understand how the fields interact with the vehicle underbody – and with the larger environment around the vehicle. Questions around the performance of the energy transfer system include, but are not limited to:
• How does the choice of wire, and how the wire is coiled, impact the system’s behavior?
• How do the properties of the ferrite magnetic materials impact performance?
• How does the size, shape, and physical layout of the ferrite tiles and aluminum shielding affect system performance?
• What effect does the material composition and shape of the vehicle underbody, where the vehicle assembly is attached, have on the energy transfer?
All these questions – and more – can be answered with computer simulation and the system optimized for performance, safety, and cost.
Of critical importance are the simulations that ensure our systems are safe for people and meet regulatory requirements, as weak magnetic and electric fields extend well beyond the ground and vehicle assembly coils. Measuring the interactions of these fields with the human body is extraordinarily difficult and, in some cases, not even possible. But, with our years of experience, we’ve developed a tremendous expertise in simulating potential exposure of the human body to these fields. This enables us to design systems that meet human exposure guidelines published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and ensure that our systems are safe for people to be around.
