•Bio-Medical Implants:- The use of bio-implants to restore biological structures of the body (e.g., retinal implant, cochlear implant etc.), or support a damaged biological structure (e.g., defibrillator and pacemakers for heart), or enhance existing biological structure. The cardiac pacemaker was the first human implanted device that has been in use for the last five decades.

•Electroceuticals :- Electroceuticals, also known as electronic medicine, are a new category of therapeutic devices that provides neuro-stimulation to a particular neural circuit and either provides stimulus in case of some neural disorder or epilepsy, or for pain management. (used in arthritis)

Hence, the implants and electroceuticals are battery- powered. So, what seems to be the problem?

•Yes, battery powered devices have always been portable, reliable to a certain degree and convenient.

•But, since the battery cannot be recharged by any means, its size is bulky and constitute large portion of the implant’s volume.

•Also, once the implant is placed inside the body, the only means to replace the batteries is to perform a surgical procedure again which both an economic and serious health burden.

•The materials that compose the batteries are highly toxic and leakage of these materials is a serious health concern.

Inductively coupled Power Transfer

•Inductive coupling is the oldest and most established WPT method.

•It is indeed a promising technology in charging implants wirelessly.

•Useful since the relative permeability of any human tissue is close to 1.

Challenges:-

1. For high power transfer, the coupling coefficient needs to be high.

2. The method is highly sensitive to any lateral or angular misalignment.

3. High frequency ensures higher power transfer; but suffers from the SAR limit bottleneck.

Motivation: - The idea of Partial Power Processing first appeared in a 1996 paper, “An Advanced Photovoltaic Array Regulator Module” published by Mr. Robert M. Button. The focus was on designing small, reliable, and inexpensive spacecraft and satellites, mostly in LEO (Low Earth Orbit). The concept of Partial Power Processing involves processing a small amount of power by the power converter, while most of the power flows from the input to the output without being processed. Hence, such a topology provides higher efficiency and higher power density.

Applications: - There is a huge range of applications, namely, in DC-DC Transformer, power processing of solar photovoltaic string power modules, power modules for spacecraft, power modules for EV battery charging, etc.

Load Resonant Converters are a class of power converters known for efficiently transferring power due to their inherent soft switching. Since these converters operate at high frequency, the size of magnetics reduces, thus increasing the power density of the power converter.

Hence, resonant converters are increasingly being used in power supplies for consumer electronics, electric vehicles, space modules and diagnostics devices like X-ray machines, CT scanner and MRI machines.