A System-Level Demonstration of Low-Frequency Magnetoelectric Power Transfer System

This letter presents a complete system-level demonstration of a low-frequency magnetoelectric (ME) wireless power transfer (WPT) system for low-voltage applications. The proposed WPT system incorporates a trilayered ME transducer featuring polyvinylidene fluoride as the piezoelectric layer and Metglas as the magnetostrictive layer. The dimension of the ME device has been micromachined into a dimension of 3.5 × 5 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{2}$</tex-math></inline-formula> to operate it at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\approx$</tex-math></inline-formula> 50 kHz. The ME device generates an output voltage of 0.4 V at a 0.4 Oe magnetic field. The corresponding power across an optimum load of 8 k<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Omega$</tex-math></inline-formula> is 6.65 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\upmu$</tex-math></inline-formula>W. The alignment orientation study of the ME device confirms that its radiation characteristics are similar to those of the loop antenna. The maximum voltage degradation in the azimuth and elevation planes is 5<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\%}$</tex-math></inline-formula> and 15<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\%}$</tex-math></inline-formula>, respectively. Moreover, a power management circuit (PMC) is designed to extract maximum power from the ME device and generate a regulated DC voltage. The PMC consumes an area of 6.5 × 5.5 cm<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{2}$</tex-math></inline-formula> and is capable of producing 2.5 V from an input voltage ranging from 0.7 to 5 V, with the peak efficiency of 85<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\%}$</tex-math></inline-formula>.