Impedance Matching and Power Division Using Impedance Inverter for Wireless Power Transfer via Magnetic Resonant Coupling

An Efficiency Enhancement Technique for a Wireless Power Transmission System Based on a Multiple Coil Switching Technique

“…To obtain maximum efficiency for a WPT system, several methods have been proposed and studied in prior works [11][12][13][14][15][16][17][18][19][20][21]. These methods consist of adaptive circuits to optimize efficiency based on frequency control, impedance matching control, Q-factor tuning control and adjusting the coupling coefficient.…”

“…However, the technique violates the frequency standards (Industrial Scientific Medical (ISM) Band) of wireless power transmission as it requires a wide frequency bandwidth. In [12,[14][15][16][17]22], adaptive impedance matching-based efficiency improvement is proposed. However, the range of tuning to obtain optimal efficiency was limited by the varactors employed in the circuit, and additionally, varactor losses reduced the total efficiency of the system.…”

Design of LCC Impedance Matching Circuit for Wireless Power Transfer System Under Rectifier Load

“…The particular solution of (15) can be described in (20).The coefficient C 4 and C 5 are calculated by (21). Then u L (t), i L21 (t), u C21 (t) can be described in (22)-(24) when 0 ≤ ωt < θ. β in (23) reflects the high frequency component in i L21 (t), and …”

“…In many applications, such as electric vehicle wireless charger and mobile phone wireless charger, WPT system outputs are direct voltage and current, and always use rectifier circuit to convert high frequency alternating current into direct current, and then supply DC power for actual load, or other DC-DC converters [18]- [20]. Thus the load of secondary coil is a nonlinear rectifier load, and the impedance matching design becomes more complicated than linear load.…”

Design of Peak Efficiency of 85.3% WPC/PMA Wireless Power Receiver Using Synchronous Active Rectifier and Multi Feedback Low-Dropout Regulator

“…Whatever we use the charging technique for, maintaining a high efficiency is necessary which is important because low efficiency will produce heat from the receiver which creates several problems. Under normal conditions, a WPT system has more than 5 W of power at its input, low efficiency of the receiver causes heat which reduces the receiver efficiency [2][3][4][5][6]. Usually, the whole efficiency of wireless power receiver (WPR) is controlled by the rectifier [7].…”