Wireless power transfer topology analysis for inkjet-printed coil

Abstract

The fabricated inkjet-printed coils (IPCs) are a suitable candidate for near-field wireless power transmission (WPT) to the next generation of high-performance implantable medical devices with extreme size constraints that will target intraocular and intracranial spaces. It is a challenging task for anyone to design an efficient inductive link for power transmission as, the secondary coil (receiver element) is placed 3 mm under the skin surface. This paper focuses on an analytical comparison among the basic four topologies of the WPT system in terms of compensation requirement and power efficiency. Hence, designers can choose the best possible topology depending on the coupling coefficient, coil design, and load impedance. In this work, the printed coil is designed with 10 layers of 10 μm thickness, respectively, in both cases. The effect of IPCs on the secondary side is briefly analyzed by considering the parasite resistance of the coil for compensation; the behavior of the system is not significantly affected by using the printed coils for compensation on the primary side. As the compensating capacitance does not depend on the parasite resistance, the series–series topology is preferable for the WPT system. The efficiency decreases due to the presence of parasite resistance in the printed coils. Moreover, it is required to choose an efficient topology as the efficiency varies from 56% to only 38%.

Keywords

• wireless power transmission
• inkjet printed coil
• compensation
• parasite resistance
• power transfer efficiency