US-12620835-B2 - Method of wirelessly transmitting power and device for performing the method

US12620835B2US 12620835 B2US12620835 B2US 12620835B2US-12620835-B2

Abstract

Provided is a method of wirelessly transmitting power and a device for performing the method. The wireless power transmission device includes a transmission coil configured to wirelessly transmit power to at least one of a plurality of receivers according to a transmission frequency and a processor configured to control at least one of the transmission frequency or resonant frequencies of the plurality of receivers, and the processor is configured to set the resonant frequencies of the plurality of receivers differently based on the transmission frequency at which the wireless power transmission device wirelessly transmits power, determine a transmission amount of power to be wirelessly transmitted to each of the plurality of receivers, and change at least one of the transmission frequency or the resonant frequencies of the plurality of receivers based on the transmission amount.

Inventors

Jung Ick Moon
Gwangzeen Ko
Sang-Won Kim
Seong-Min Kim
In Kui Cho

Assignees

ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE

Dates

Publication Date: 20260505
Application Date: 20230131
Priority Date: 20220429

Claims (10)

1 . A wireless power transmission device comprising: a transmission coil configured to wirelessly transmit power to at least one of a plurality of receivers according to a transmission frequency; and a processor configured to control at least one of the transmission frequency or resonant frequencies of the plurality of receivers, wherein the processor is configured to: set at least one of the resonant frequencies of the plurality of receivers to a frequency lower than the transmission frequency; and set at least one of the resonant frequencies of the plurality of receivers to a frequency higher than the transmission frequency based on the transmission frequency at which the wireless power transmission device wirelessly transmits power, thereby transmitting power to the plurality of receivers simultaneously; determine a transmission amount of power to be wirelessly transmitted to each of the plurality of receivers; and change at least one of the transmission frequency or the resonant frequencies of the plurality of receivers based on the transmission amount, and change the resonant frequency of a first receiver among the plurality of receivers so that the resonant frequency of the first receiver approaches the transmission frequency, when the transmission amount for the first receiver is greater than the transmission amounts for the other receivers.
2 . The wireless power transmission device of claim 1 , wherein each of the plurality of receivers is disposed on one side and another side of the transmission coil.
3 . The wireless power transmission device of claim 1 , wherein the processor is configured to change the transmission frequency so that the transmission frequency is close to one of the resonant frequencies of the plurality of receivers.
4 . The wireless power transmission device of claim 1 , wherein the processor is configured to determine the transmission amount based on a battery state and demanded power information received from each of the plurality of receivers.
5 . A wireless power transmission device comprising: a transmission coil configured to wirelessly transmit power to at least one of a plurality of receivers according to a transmission frequency; and a processor configured to control at least one of the transmission frequency or resonant frequencies of the plurality of receivers, wherein the processor is configured to: set at least one of the resonant frequencies of the plurality of receivers to a frequency lower than the transmission frequency; and set at least one of the resonant frequencies of the plurality of receivers to a frequency higher than the transmission frequency, thereby transmitting power to a plurality of receivers simultaneously; identify the transmission frequency to wirelessly transmit power and the resonant frequencies of the plurality of receivers, the resonant frequencies being different from each other; receive demanded power information from the plurality of receivers; determine a transmission amount of power to be wirelessly transmitted to each of the plurality of receivers, based on the demanded power information; determine a parameter related to the transmission frequency and the resonant frequencies of the plurality of receivers, based on the transmission amount; wirelessly transmit power to the plurality of receivers based on the parameter; and change the resonant frequency of a first receiver among the plurality of receivers so that the resonant frequency of the first receiver approaches the transmission frequency, when the transmission amount for the first receiver is greater than the transmission amounts for the other receivers.
6 . The wireless power transmission device of claim 5 , wherein the processor is configured to determine the parameter so that the transmission frequency is close to one of the resonant frequencies of the plurality of receivers.
7 . A method of wirelessly transmitting power, the method comprising: setting resonant frequencies of a plurality of receivers differently based on a transmission frequency at which a wireless power transmission device wirelessly transmits power; determining a transmission amount of power to be wirelessly transmitted to each of the plurality of receivers; changing at least one of the transmission frequency or the resonant frequencies of the plurality of receivers based on the transmission amount, wherein the setting of the resonant frequencies of the plurality of receivers differently comprises: setting at least one of the resonant frequencies of the plurality of receivers to a frequency lower than the transmission frequency; and setting at least one of the resonant frequencies of the plurality of receivers to a frequency higher than the transmission frequency, thereby transmitting power to a plurality of receivers simultaneously; and changing the resonant frequency of the first receiver so that the resonant frequency of the first receiver approaches the transmission frequency, when the transmission amount for a first receiver among the plurality of receivers is greater than the transmission amounts for the other receivers, wherein the wireless power transmission device comprises: a transmission coil configured to wirelessly transmit power to at least one of the plurality of receivers according to the transmission frequency; and a processor configured to control at least one of the transmission frequency or the resonant frequencies of the plurality of receivers.
8 . The method of claim 7 , wherein the plurality of receivers is disposed in different directions based on the transmission coil.
9 . The method of claim 7 , wherein the changing of at least one of the transmission frequency or the resonant frequencies of the plurality of receivers comprises changing the transmission frequency so that the transmission frequency is close to one of the resonant frequencies of the plurality of receivers.
10 . The method of claim 7 , wherein the determining of the transmission amount comprises determining the transmission amount based on a battery state and demanded power information received from each of the plurality of receivers.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of Korean Patent Application No. 10-2022-0053432 filed on Apr. 29, 2022, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. BACKGROUND 1. Field of the Invention One or more embodiments relate to a method of transmitting wireless power and a device for performing the method. 2. Description of the Related Art In wireless charging technology, the ability to transmit power energy between a transmitter and a receiver is called transmission efficiency or system efficiency. In order to improve the power transmission performance of a wireless power transceiver, a resonant frequency and a power transmission frequency determined by a coil and an internal circuit of a transmitter and a receiver must be the same. In order to match a resonant frequency with a power transmission frequency, the reactance (a combination of inductance and capacitance) of a coil and a circuit must be set to zero to resonate. Meanwhile, as the technical field of applying wireless charging spreads from charging smartphones and electric vehicles to small mobile robots, it is necessary to charge multiple receivers simultaneously with one transmitter to reduce the space and cost required to install a transmitter. When charging multiple receivers simultaneously with one transmitter, the transmitter may receive the same power under exactly the same conditions as the load state (e.g., the remaining battery) of the receiver and coil characteristics, but when the conditions of the receiver are different, it is necessary to distribute power appropriately and supply it to the receiver. SUMMARY Embodiments provide a method of wirelessly and efficiently transmitting power to a plurality of receivers disposed on each side of a transmitter in a wireless charging system simultaneously, and a device for performing the method. Embodiments provide a device that may prevent the performance of a wireless charging system from deteriorating by causing receivers disposed on each side of a transmitter to interfere with each other and perform a method of wirelessly transmitting power to control power to be wirelessly transmitted. According to an aspect, there is provided a device for wirelessly transmitting power according to various embodiments including a transmission coil configured to wirelessly transmit power to at least one of a plurality of receivers according to a transmission frequency and a processor configured to control at least one of the transmission frequency or resonant frequencies of the plurality of receivers, and the processor is configured to set the resonant frequencies of the plurality of receivers differently based on the transmission frequency at which the wireless power transmission device wirelessly transmits power, determine a transmission amount of power to be wirelessly transmitted to each of the plurality of receivers, and change at least one of the transmission frequency or the resonant frequencies of the plurality of receivers based on the transmission amount. Each of the plurality of receivers may be disposed on one side and another side of the transmission coil. The processor may be configured to set at least one of the resonant frequencies of the plurality of receivers to a frequency lower than the transmission frequency and set at least one of the resonant frequencies of the plurality of receivers to a frequency higher than the transmission frequency. The processor may be configured to change the transmission frequency so that the transmission frequency is close to one of the resonant frequencies of the plurality of receivers. The processor may be configured to change at least one of the resonant frequencies of the plurality of receivers so that at least one of the resonant frequencies of the plurality of receivers is close to the transmission frequency. The processor may be configured to determine a target receiver to change a resonant frequency among the plurality of receivers based on the transmission amount and change at least one of the resonant frequency of the target receiver or the transmission frequency so that the resonant frequency of the target receiver and the transmission frequency are close to each other based on the transmission amount for the target receiver. The processor may be configured to determine the transmission amount based on a battery state and demanded power information received from each of the plurality of receivers. According to an aspect, there is provided a device for wirelessly transmitting power according to various embodiments including a transmission coil configured to wirelessly transmit power to at least one of a plurality of receivers according to a transmission frequency and a processor configured to control at least one of the transmission frequency or resonant frequencies of the plurality of receivers, and the processor is configured to i