Load‐independent inverse class‐E ZVS inverter and its application to wireless power transfer systems

Abstract

This paper proposes a load‐independent inverse class‐E zero‐voltage switching (ZVS) inverter. The proposed inverter achieves the constant output current and the ZVS at any load resistance without any control. The waveforms and design equations of the proposed inverter are shown. Besides, a wireless‐power‐transfer system was implemented using the proposed inverter. The designed WPT system kept the constant output voltage and the ZVS against load variations, which denoted the effectiveness of the proposed inverter and validities of the analytical equations.

Capacitive Wireless Power Transfer System with a 3D-Functional Coupler for Maintenance-Free Industrial Robots

“…Optimized inverter load calculations based on frequency and power parameters yielded a value of 31 Ω. To ensure a zero-voltage switching (ZVS) operation in the FETs irrespective of the load variations induced by tool conditions, we employed a load-independent inverter [16,17,18]. When the imaginary part of the input impedance as observed from the inverter is small, ZVS is sustained, enabling constantcurrent/-voltage (CC/CV) output operation.…”

Analysis and Design of High-Frequency WPT System Using Load-Independent Inverter With Robustness Against Load Variations and Coil Misalignment

“…Class-E [12] ZVS CV Series Class-Φ [13] ZVS CV Series Class-E/F [14] ZVS CC Series Class-E −1 [15] ZCS CV Parallel Class-E [16] ZVS CC Parallel Class-E −1 [17] ZCS CC Series Class-E [18] ZVS CC Parallel against load variations. The inverter works with the LI mode even against coil misalignment because the output reactance of the transmitter is consistent in the proposed configuration.…”

Wireless charging for cardiac pacemakers based on class‐D power amplifier and a series–parallel spider‐web coil

“…The two coils are coupled by mutual inductance (M), and are reported according to the SWC properties and the transfer distance between SWC–TX and SWC–RX. The value of M between SWC–TX and SWC–RX was determined using Equation (4) 29,46 as follows: where μ° is the permeability of free space (4π × 10 −7 ) 57 ; and N SWC‐TX and N SWC‐RX are the numbers of turns in the transmitter and receiver coils; D SWC‐TX and D SWC‐RX are the outer diameters of the transmitter and receiver coils; X is the air gap distance between SWC–TX and SWC–RX coils. From the laws of self‐induction and the calculated M, the coupling factor can be calculated as a percentage of interlock, determined from Equation (5) 57 as follows: The delivered power on the receiver side (P out ) was determined using Equation (6).…”

“…The value of M between SWC–TX and SWC–RX was determined using Equation (4) 29,46 as follows: where μ° is the permeability of free space (4π × 10 −7 ) 57 ; and N SWC‐TX and N SWC‐RX are the numbers of turns in the transmitter and receiver coils; D SWC‐TX and D SWC‐RX are the outer diameters of the transmitter and receiver coils; X is the air gap distance between SWC–TX and SWC–RX coils. From the laws of self‐induction and the calculated M, the coupling factor can be calculated as a percentage of interlock, determined from Equation (5) 57 as follows: The delivered power on the receiver side (P out ) was determined using Equation (6). To calculate the efficiency of the setup, power transfer efficiency was determined using Equation (7) 58 : where the voltage and current denoted in Equation (6) are the load voltage and the load current, respectively.…”

“…T A B L E 2 Compensated capacitor values for the WPT-SP-SWC system where μ is the permeability of free space (4π Â 10 À7 ) 57 ; and N SWC-TX and N SWC-RX are the numbers of turns in the transmitter and receiver coils; D SWC-TX and D SWC-RX are the outer diameters of the transmitter and receiver coils; X is the air gap distance between SWC-TX and SWC-RX coils. From the laws of self-induction and the calculated M, the coupling factor can be calculated as a percentage of interlock, determined from Equation ( 5) 57 as follows:…”