Below are the questions asked during the live event, along with their respective answers.
Q: Have you estimated the emissions intensity from spurious frequencies created by typical efficient PWM AC power electronics source driving the transmit coil and the overall system?
A: We have calculated the conducted emissions on the DC input of a WPT system by circuit simulations. The obtained results have shown as it is possible to make the system widely compliant with the limits (e.g. CISPR 25) using only a very simple input filter. On the vehicle side, the conducted emission is mainly generated from the rectifier while the noise from the receiving side is blocked by the coils and by the compensation networks which act as a bandpass filter. For further readings:
[1] T. Campi, S. Cruciani, F. Maradei, and M. Feliziani, “Conducted emission of wireless power transfer charging system in electric vehicle,” 2017 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (EMCSI), Washington DC, USA, pp. 619-622, 7-11 Aug. 2017.
[2] M. Suzuki et al., “Conducted Emission in an 85 kHz, 50 kW WPT System with Opposite-Phase Transfer and Spread Spectrum,” 2019 IEEE PELS Workshop on Emerging Technologies: Wireless Power Transfer (WoW), London, United Kingdom, pp. 1-4, 2019
Q: Currently, are any of the commercial EVs in the market equipped for wireless charging?
A: The application of the WPT technology to EVs is under development by many car manufacturers, e.g., BMW, Tesla, and Nissan are ready to equip their EVs with wireless charging pads. However, nowadays, there are no commercial EVs in the market equipped with a factory WPT system, at least to my knowledge. Currently, only aftermarket kits are available to be used for EV wireless charging, e.g., Plugless Charging Upgrade [1] or system proposed by Witricity [2].
[1] Plugless. Online: https://www.pluglesspower.com/
[2] Witricity. Online: https://witricity.com/products/automotive/
Q: Human health safety. Are we going to test this on real living creatures-people or only phantoms or engineering models? Please advise.
A: Currently the assessment of the dosimetric quantities and the compliance with basic restrictions (e.g. internal electric field for ICNIRP 2010 at 85 kHz) can be only carried out by numerical simulations, since measurements of physical quantities inside the human body are not allowable, while well-recognized phantoms do not exist in the market at the considered frequency. The simulations are performed adopting high definition human body models with a small resolution (up to 1 mm). Since it is not possible to directly measure the dosimetric quantities inside the human body, some experimental measurements could be performed on animals, however, they are very difficult at 85 kHz.