Efficient deactivation of unused LCC inverter for multiple transmitter wireless power transfer

Abstract

The study addresses the difficulties in deactivating an unused transmitter (TX) element for a multiple-transmitter wireless power system that is driven by LCC resonant inverters. One difficulty of TX deactivation is a high-level of unwanted circulating current in unused TX coil, which increases the losses in unused TX. To suppress the unwanted current without the aid of high-voltage isolated switches and detuning capacitors, it is proposed that low-side switches in LCC bridge should be constantly turned on. The other difficulty is the runtime detuning of LCC resonant inverter in response to the activation or deactivation status of adjacent TX coil, which degrades the LCC inverter efficiency. A tuning switch and capacitor cannot directly be inserted at the LCC resonant path due to high-voltage stress and complex driving scheme. Instead, this study proposes a loop that adjusts the effective inductance of the TX coil with low-voltage stress and easy gate driving, thereby increasing the LCC inverter efficiency. The loop also provides an additional power path towards the receiver so that the coil-to-coil efficiency is also increased.

A Comparative Study on Current- and Voltage-Optimized Circuit Scheme for Multiple-Transmitter and Single-Receiver WPT System

“…is system with LCC compensation is used to maximize the PDL based on the voltage-optimized scenario. Under the design equation of (15), the transmitting currents of I V,Ti based on LCC compensation are completely determined by feeding voltage values regardless of the load conditions and the coupling strengths between TXs and RX [25,26].…”

Analysis, design and evaluation of a zero‐voltage‐switching non‐resonant converter for IPT applications

“…With regard to the input current i 1 , which is the current handled by the bridge transistors, its time delay t 1 and peak amplitude I m1 can be obtained from (19) and (20), respectively. The resulting values are t 1 = 0.541 μs 77.5° and I m1 = 2.55 A.…”

“…As conclusion, IPT systems are highly reactive circuits, which usually require compensation to decrease rms currents and increase the efficiency. Most of topologies studied in the literature are based on resonant converters, which use serial, parallel and serialparallel compensation circuits to improve IPT system performance [8][9][10][11][12][13][14][15][16][17][18][19]. These converters require extra elements, thus increasing the complexity and possibly decreasing the efficiency when operating out of resonance.…”

Large-Area Free-Positioning Wireless Power Transfer to Movable Receivers

“…The use of a large Tx coil may be relatively simpler and cost effective method to generate homogeneous electromagnetic field in a large area, however, it is not a feasible option for moderate-and high-power applications because 1. unwanted electromagnetic exposure in uncoupled area, 2 low coupling 3. not able to control the power flow to multiple receivers. Therefore, the use of multiple Tx coils is the only feasible option to enable large-area WPT [7]- [9]. However, the cost and complexity is one of the main concern for multi-Tx WPT systems.…”