Page 42 - PEN eBook July 2023
P. 42
Power Supply
The inverter switching losses P were modeled by means of an equivalent current source in
sw,inv
parallel to the inverter input, whose current is given by:
The Tx and Rx conduction losses are given by:
The overall WPTS efficiency is evaluated as:
EXPERIMENTAL VERIFICATION OF WPTSes
The WPTS adopted for the validation of the proposed model is characterized by the following
operating parameters: f = 6.78 MHz, L = 7.5 μH, L = 0.93 μH, C = 1 ÷ (ω × L ) = 73.5 pF,
2
s 1 2 1s s 1
C = 1 ÷ (ω × L ) = 593 pF, Q = 150, Q = 40, Q = Q = 1,000. The WPTS is physically realized with
2
2s s 2 L1 L2 C1 C2
the Tx coil (nine turns, 70 × 70-mm diameter) and the Rx coil (eight turns, 15 × 15-mm diameter).
2
2
The Rx coil was placed centered with respect to the Tx coil at 6 mm of distance from each other,
yielding a coupling factor of K = 0.076 (calculated by means of Ansys’s high-frequency structural
simulator). Rohm’s RUF015N02 MOSFETs were adopted for the inverter and rectifier stages. Texas
42 JULY 2023 | www.powerelectronicsnews.com
