Rotary-Type Electromagnetic Power Generator Using a Cardiovascular System As a Power Source for Medical Implants

Power-harvesting devices have received attention as power supplies for implantable medical devices. Power-harvesting technologies can overcome the limitation of a battery, such as limited battery lifetime and repeated surgical interventions. However, micropower generators do not meet the energy requirements of medical implants such as neural recording, implantable hearing aids, and implantable wireless sensors. They require an electrical power from 1 to 10 mW. This paper introduces an electromagnetic power generator using blood flow and blood pressure to drive an implanted medical device. The fabricated power generator, which is composed of a tiny rotor with magnets and external coils with ferrite cores, operates within a wide blood pressure range from 6.75 to 54.75 mmHg. In addition, the total volume and weight of the generator are 3.16 cc and 24 g, respectively. Using animal and mock-up tests, we verified the ability of the self-powered device to drive the medical implants. In the animal test, we utilized a blood pump to control the blood flow and blood pressure. The generator generated a maximum electrical power of 3.4 mW (conversion efficiency of 1.04%) at a blood pressure drop of 54.75 mmHg and blood flow of 2.68 L/min.