Wirelessly Charge Electric Vehicles by Induction While Driving
By Staff Editor and Joachim G. Taiber
(Originally printed in the January issue of Elektroborse Smarthouse)
Drivers of electric vehicles should be able to charge their car in the future while they are driving. This shall be enabled via inductive charging. Hereby, alternating current generates a magnetic field within a charging plate, which induces the current into the vehicle. The alternating current is transformed into direct current and is fed into the battery. Elektrobörse Smarthouse talked to Prof. Dr. Joachim G. Taiber, professor of the Clemson University International Center of Automotive Research (CU-ICAR) and technical expert of the IEEE Transportation Electrification Initiative, about the current state of this technology.
Interview with Joachim Taiber
Staff Editor: Companies are currently doing research on a technology that should enable electrical vehicles to drive on a lane without a cable and being charged wirelessly. What is its current status?
Taiber: Currently, the commercial focus of wireless charging is on stationary use cases. This means that the consumer can recharge plug-in hybrids or full electric vehicles without using a conductive charging cable. The standardization of stationary wireless charging is addressed by the SAE working group J2954. A technical recommendation will be published at the beginning of this year and a standard should be available within the next 1-2 years.
Dynamic wireless charging is technologically feasible and has been successfully demonstrated in research prototypes. But with respect to commercialization, substantial validation work has to be done for this technology – in particular with respect to higher power transfer levels. IEEE established a working group in which academic experts, industry experts and government representatives are dealing with the “pre-standardization” of this technology.
Staff Editor: Which advantages come with dynamic wireless charging?
Taiber: The main advantage of wireless charging while the vehicle is in motion is the automation of the charging process and the resulting additional range –thus the use of an internal combustion engine as a ”range extender“ and the use of larger and thus heavier batteries are not necessary. The alternative to dynamic wireless charging is conductive fast charging. But this will cause an interruption of travel. Conductive fast charging stations are limited in the number of vehicles that can be recharged in parallel, resulting in potential waiting times.
Staff Editor: How do the costs of the necessary road modifications relate to other charging technologies?
Taiber: This is currently difficult to quantify, as dynamic wireless charging is not yet commercialized. In expert discussions, we learn that infrastructure cost are in the best case a few hundred thousand euros per kilometer, in the worst case a few million euros per kilomter – studies with robust figures can be expected in the near future. In order to get to better estimates, more physical prototypes need to be built and more business cases needs to be calculated.
Staff Editor: What do collaborations with Automotive OEM’s look like?
Taiber: The automotive OEM’s are currently focused on the rollout of stationary wireless charging stations. With the standardization framework provided by SAE J2954, the automotive suppliers can work with more robust system development parameters. Thus, automotive OEM’s have a number of supplier choices with respect to the technology of stationary wireless charging. Dynamic wireless charging systems are currently still in the research phase and automotive suppliers are monitoring the technology development – it is currently too early for supplier decisions.
Staff Editor: Which are the largest technical challenges?
Taiber: The larger challenges are in the standardization of the energy transfer frequencies, the acceptable limits of electromagnetic field strengths to minimize health risks, the geometrical parameters of the positioning of the coils (package-relevant), and the cooling technologies for higher energy transfer power levels. As mentioned before – the challenges for stationary wireless charging appear to be under control and are within a technological convergence corridor, the suppliers are developing commercial solutions and standards are also in development.
Staff Editor: Are there European standardization efforts?
Taiber: SAE and IEC synchronize their standardization efforts with a focus on stationary wireless charging. IEEE is committed to generating dynamic inductive charging and also takes into account the IEEE communication standards.
Staff Editor: In what timeframe can these projects be implemented?
Taiber: The first commercial solutions for stationary wireless charging are currently being introduced to the market – first as “aftermarket“ solutions. OEM solutions can be expected in at least three to five years. Commercial solutions for dynamic wireless charging will come later. It should also be noted that rules for infrastructure financing and technical standardization should be developed prior to commercialization.
Staff Editor: What does the new technology mean for technicians?
Taiber: For stationary wireless charging the electrical installation process can be compared with the installation of conductive charging systems. The most important difference is that instead of a cable, coils are being used for the energy transfer. The energy transfer power levels between contacted-based and contactless charging systems are comparable. But with contactless charging no metallic or living objects are allowed between the primary and secondary coil. Therefore, it is expected that vehicles are equipped with the ability to detect foreign objects in order to avoid malfunctions and prevent possible harm to pets.
Prior to coming to Clemson in 2010, Dr. Joachim Taiber was heading the Information Technology Research Office at the BMW ITRC (Information Technology Research Center) at CUICAR (Clemson University International Center of Automotive Research). He designed and implemented an open innovation business model with leading information & communication technology companies as a first of its kind in the automotive industry at this center. Since the ITRC started its operation in 2005 he completed more than 50 research projects in close cooperation with universities, especially in cooperation with faculty members from ECE, School of Computing and Mechanical Engineering at Clemson University. He also created a 4G wireless communication infrastructure at a high-speed track which is considered the first of its kind in the automotive industry.