Three-dimensional wireless power charging system and method for tracking mutual inductance between transceivers thereof

Abstract

The present disclosure relates to a three-dimensional wireless power charging system and a method for tracking mutual inductance between transceivers thereof. The transmission system for three-dimensional wireless power charging includes a plurality of transmitters and a controller configured to control the plurality of transmitters. Each of the transmitters is configured to receive a control signal for determining a transmission current of an arbitrary magnitude from the control unit, and adjust the input voltage of the transmission terminal by the input impedance of the transmission terminal while outputting the corresponding transmission current. The control unit is configured to monitor the input voltage of each of the transmitters and track mutual inductances between the plurality of transmitters and a receiver by using data including the transmission current set in each of the transmitters and the input voltage monitored by each of the transmitters.

Description

3D wireless power charging system and method for tracking mutual inductance between the same's transceiver

[0001] The present disclosure relates to mutual inductance tracking.

[0002] As the demand for the Internet of Things (IoT) and portable devices increases, there is a need for wireless charging technology that considers power efficiency. However, current wireless charging technology is applicable only within a limited range between transmitters and receivers, and charging efficiency decreases significantly depending on the distance, location, orientation, state, movement, and number of receivers. There is a need for 3D wireless charging technology that can efficiently wirelessly charge receivers by shaping the transmitted magnetic field in three-dimensional space to match various receiver states. To achieve optimal efficiency in 3D wireless power charging, the mutual inductance between transmitters and receivers must be known in order to output the optimal transmitted current for optimal efficiency.

[0003] The frequency sweeping method is known as an existing method for tracking mutual inductance between transmitters and receivers; however, since this is primarily used in strongly-coupled systems, it is difficult to use in weakly-coupled systems such as 3D wireless power charging systems. Meanwhile, although there is a transmit / receive voltage / current monitoring method applicable to weakly-coupled systems, it requires the use of only a single transmitter; therefore, when applied to 3D wireless power charging systems, the power of transmitters not used for tracking must be turned off. Consequently, existing transmit / receive voltage / current monitoring methods have the disadvantage that the power of transmitters must be repeatedly turned on and off during mutual inductance tracking, and the large transmit current required for sufficient power induction at the receiver can burden the operation of the transmitting system. A new mutual inductance tracking technology between transmitters applicable to 3D wireless charging systems is required to solve these problems.

[0004] The present disclosure provides a three-dimensional wireless power charging system and a method for tracking mutual inductance between the transmitter and receiver thereof.

[0005] The present disclosure provides a method for simultaneously tracking mutual inductance between transmitters and receivers using the voltage / current of multiple transmitters and multiple receivers.

[0006] A transmission system for three-dimensional wireless power charging according to some embodiments comprises a plurality of transmitters and a control unit for controlling the plurality of transmitters. Each transmitter is implemented to receive a control signal from the control unit for determining a transmission current of arbitrary size and to adjust the input voltage of the transmitter by the input impedance of the transmitter while outputting the transmission current. The control unit is implemented to monitor the input voltage of each transmitter and to track the mutual impedances between the plurality of transmitters and the receiver using data including the transmission current set for each transmitter and the input voltage monitored by each transmitter.

[0007] Each transmitter may include a current mode converter implemented to adjust the input voltage of the transmitter by the input impedance of the transmitter while outputting a transmission current set by the control unit.

[0008] The above data may further include equivalent circuit parameter values ​​of the plurality of transmitters and the receiver, and the voltage and current of the receiver.

[0009] The control unit may be implemented to input values ​​included in the data into equations regarding transmission currents and reception currents, and to calculate the mutual inductances and the load of the receiver, which are unknown variables in the equations. The equations may be relationships derived by superimposing the transmission currents and reception currents in each mode classified according to the input voltage on / off of each transmitter.

[0010] The above control unit may be implemented to acquire the data while all of the plurality of transmitters are operating.

[0011] The transmitting coils of the plurality of transmitters mentioned above can be configured to be orthogonal to each other.

[0012] A method of operation of a transmitting system for three-dimensional wireless power charging according to some embodiments comprises the steps of: setting each transmitter to output a transmission current of arbitrary size while all of the transmitters are operating; monitoring an input voltage adjusted to output the transmission current at each transmitter; and tracking mutual impedances between the plurality of transmitters and a receiver using data including the transmission current set at each transmitter and the input voltage monitored at each transmitter.

[0013] The above operation method may further include the steps of obtaining equivalent circuit parameter values ​​of the plurality of transmitters and the receiver, and obtaining the voltage and current of the receiver.

[0014] The above data may further include the equivalent circuit parameter values, and the voltage and current of the receiver.

[0015] The step of tracking the mutual impedances involves inputting the values ​​included in the data into equations regarding the transmission currents and reception currents, and calculating the unknown mutual inductances and the load of the receiver in the equations. The equations may be relationships derived by superimposing the transmission currents and reception currents in each mode classified according to the input voltage on / off of each transmitter.

[0016] Each transmitter may include a current mode converter implemented to adjust the input voltage of the transmitter by the input impedance of the transmitter while outputting a transmission current set by the control unit.

[0017] The transmitting coils of the plurality of transmitters mentioned above can be configured to be orthogonal to each other.

[0018] According to the present disclosure, mutual inductance can be measured without the need to repeatedly turn the power of the transmitter on and off, thereby increasing the stability of the three-dimensional wireless power charging system and also enabling high-speed measurement of mutual inductance.

[0019] According to the present disclosure, mutual inductance can be measured according to various states of the receiver, and can be utilized for wireless power charging of various devices.

[0020] FIG. 1 is a configuration diagram of a three-dimensional wireless power charging system according to one embodiment.

[0021] FIG. 2 is a diagram illustrating mutual inductance between a transmitter and a receiver according to one embodiment.

[0022] Figure 3 is a diagram illustrating a mutual inductance tracking method using a conventional voltage / current monitoring method.

[0023] FIG. 4 is a diagram illustrating the mutual inductance simultaneous tracking method of the present disclosure.

[0024] FIG. 5 is a circuit diagram illustrating the structure of a transmitter of the present disclosure in an exemplary manner.

[0025] FIG. 6 is a flowchart illustrating a mutual inductance tracking method of a three-dimensional wireless power charging system according to one embodiment.

[0026] Embodiments of the present disclosure are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present disclosure in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals.

[0027] In the description, drawing symbols and names are provided for convenience of explanation and are not limited to drawing symbols or names.

[0028] In the description, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, terms such as "…part," "…unit," and "module" as used in the specification refer to a unit that processes at least one function or operation, and this may be implemented in hardware, software, or a combination of hardware and software.

[0029] In the description, expressions written in the singular may be interpreted as singular or plural unless explicit expressions such as "one" or "singular" are used. Terms containing ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms may be used for the purpose of distinguishing one component from another.

[0030] FIG. 1 is a configuration diagram of a three-dimensional wireless power charging system according to one embodiment, and FIG. 2 is a diagram explaining the mutual inductance between a transmitter and a receiver according to one embodiment.

[0031] Referring to FIG. 1, a three-dimensional wireless power charging system (10) may include a transmitting system (100) comprising multiple transmitters, and a receiver (200) that is wirelessly charged by the transmitting system (100). The transmitting system (100) may include a transmitter (TX#1, TX#2, TX#3) (110: 110-1, 110-2, 110-3) composed of three orthogonal coils, and a control unit (130). Each transmitter may include a transmitting coil (TX coil) and a power amplifier connected to the corresponding transmitting coil. The control unit (130) may be a Micro Control Unit (MCU) and may be configured in various other ways. The transmitting coils (TX coil #1, TX coil #2, TX coil #3) of the transmitting modules are orthogonal coils arranged on orthogonal planes in three-dimensional space.

[0032] Here, the three-dimensional wireless power charging system (10) is a loosely coupled system in which the transmitter and receiver are loosely coupled, and has the advantage of a wide charging area.

[0033] A three-dimensional wireless power charging system (10) can be represented by an equivalent circuit (20) as shown in FIG. 2, and in order to achieve optimal efficiency of three-dimensional wireless power charging, the mutual inductance M between the transmitter and receiver 1, We need to track M2 and M3.

[0034] FIG. 3 is a diagram illustrating a mutual inductance tracking method by a conventional voltage / current monitoring method, and FIG. 4 is a diagram illustrating a mutual inductance simultaneous tracking method of the present disclosure.

[0035] One method for tracking mutual inductance is the voltage / current monitoring method. The voltage / current monitoring method can detect the current or voltage of the transmitter and receiver via BLE (Bluetooth low energy) and calculate the mutual inductance M between the transmitter and receiver as shown in Equation 1.

[0036] [Mathematical Formula 1]

[0037]

[0038] Referring to FIG. 3, the conventional voltage / current monitoring method is a method for measuring mutual inductance between a single transmitter and a receiver using only a single transmitter. Therefore, when tracking mutual inductance using the conventional voltage / current monitoring method in a three-dimensional wireless power charging system (10) including multiple transmitters, the transmitting system (100) turns off the power of transmitters TX#2 and TX#3 that are not used for tracking, and the transmitting current I of transmitter TX#1 TX1 Receiver voltage V due to RX Based on this, the mutual inductance M1 can be tracked. Next, the transmitting system (100) turns off the power to transmitters TX#1 and TX#3, and the transmitting current I of transmitter TX#2 TX2 Receiver voltage V due to RX Based on this, the mutual inductance M2 can be tracked. Finally, the transmitting system (100) turns off the power to receivers TX#1 and TX#2, and the transmitting current I of transmitter TX#3 TX3 Receiver voltage V due to RX Based on this, mutual inductance M3 can be traced.

[0039] As such, in a multi-transmitter structure, the transmitters must be repeatedly switched on and off to track individual mutual inductances, and the tracking time increases as individual mutual inductance tracking is repeated using a single transmission current. Furthermore, since a large transmission current flows from the transmitter to induce sufficient power at the receiver, it can place a burden on the operation of the transmission system and results in a short tracking distance.

[0040] Referring to FIG. 4, the three-dimensional wireless power charging system (10) of the present disclosure can simultaneously track mutual inductances M1, M2, and M3 between transmitters and receivers using the voltage or current of multiple transmitters and the voltage or current of a single receiver when power is applied to transmitters TX#1, TX#2, and TX#3.

[0041] The three-dimensional wireless power charging system (10) can be assumed to be a linear system since the transmitting coil and the receiving coil are weakly coupled. In the equivalent circuit (20), the mutual inductances M1, M2, M3 and the load Z of the receiver L It is assumed that is an unknown and all other parameters are known values. Then, according to the characteristics of a linear system, the superposition principle is applied to the mutual inductances M1, M2, M3 and the receiver load Z L can calculate.

[0042] First, the equivalent circuit (20) can be classified into three modes depending on the on / off input voltage of each transmitter. Mode 1 is a state in which only transmitter TX#1 is operating, i.e., V TX1 It is assumed that this is in the ON state and the remaining input voltages are in the OFF state. Mode 2 is a state where only transmitter TX#2 is operating, i.e., V TX2 It is assumed that this is in the ON state and the remaining input voltages are in the OFF state. Mode 3 is a state where only transmit module #3 is operating, i.e., V TX3 Assume that this is in the ON state and the remaining input voltages are in the OFF state.

[0043] In the equivalent circuit of each mode, equations for each transmitting and receiving circuit can be derived using Kirchhoff's voltage law, and the transmitting and receiving currents for each transmitter in the corresponding mode can be derived through a system of equations.

[0044] Specifically, by applying Kirchhoff's voltage law to the nth transmitter TX#n, an equation like Equation 2 can be derived, and by applying Kirchhoff's voltage law to the receiver RX, an equation like Equation 3 can be derived.

[0045] [Mathematical Formula 2]

[0046]

[0047] [Mathematical Formula 3]

[0048]

[0049] In Mode 1, where only transmitter TX#1 is operating, the equations for the transmitting and receiving circuits can be expressed as Equation 4. By solving the system of equations in Equation 4, the transmitting currents and receiving currents in Mode 1, I TX1,Mode1 , I TX2,Mode1 , I TX3,Mode1 , I RX,Mode1 It can be derived. Similarly, from the system of equations derived from the transmitting and receiving circuits in Mode 2 where only transmitter TX#2 is operating, the transmitting currents and receiving current I in Mode 2 can be derived. TX1,Mode2 , I TX2,Mode2 , I TX3,Mode2 , I RX,Mode2 ...can be derived. From the system of equations derived from the transmitting and receiving circuits in Mode 3 where only transmitter TX#3 is operating, the transmitting currents and receiving current I in Mode 3 can be derived. TX1,Mode3 , I TX2,Mode3 , I TX3,Mode3 , I RX,Mode3 It can induce.

[0050] [Mathematical Formula 4]

[0051]

[0052]

[0053]

[0054]

[0055] By applying the superposition principle of the currents induced in each mode, as shown in Equation 5, the transmitted currents and the received current, I TX1 , I TX2 , I TX3 , I RX can be induced.

[0056] [Mathematical Formula 5]

[0057]

[0058]

[0059]

[0060]

[0061] Here, in the equivalent circuit (20), mutual inductances M1, M2, M3 and the receiver's load Z L Assuming that is an unknown and all other parameters are known values, the transmit and receive currents are given by the mutual inductances M1, M2, M3 and the receiver load Z L It can be expressed as a function of. Solve the system of equations in Equation 5 to obtain the mutual inductances M1, M2, M3 and the receiver load Z L It can calculate.

[0062] R, L, and C of the equivalent circuit (20) are known constants, and the voltage V of the receiver RX and current I RX It is assumed that is a value obtainable via BLE. Then, the input voltage V of each transmitter TX and transmission current I TX A value for is required. To this end, each transmitter uses a current mode converter (current mode step-down converter) to set an arbitrary transmission current I TXThe input voltage V of the transmitter is to be output. TX Adjust , and input impedance Z TX Input voltage V adjusted according to TX It can monitor.

[0063] FIG. 5 is a circuit diagram illustrating the structure of a transmitter of the present disclosure in an exemplary manner.

[0064] Referring to FIG. 5, the transmitter TX#n (110-n) may include a current mode converter (111) and a transmitting end (112).

[0065] The current mode converter (111) receives a transmission current I of any size from the control unit (130). TX When a control signal (e.g., digital-to-analog converter, DAC) determining is received, the output voltage is fed back to the input impedance Z of the transmitting end (112). TX Input voltage V according to TX By adjusting the set transmission current I TX It consists of a circuit that outputs.

[0066] The transmitting unit (112) may be composed of, for example, a power amplifier, a matching circuit, and a transmitting coil (TX coil). Voltage V regulated by the current mode converter (111). TX It can be supplied as the drain voltage of the power amplifier.

[0067] Each transmitter has a transmission current I determined by the control unit (130). TX Output, provided that the input impedance Z of the transmitter TX Input voltage V adjusted according to TX By monitoring, parameter values ​​required for calculating mutual inductance can be obtained.

[0068] FIG. 6 is a flowchart illustrating a mutual inductance tracking method of a three-dimensional wireless power charging system according to one embodiment.

[0069] Referring to FIG. 6, a control unit (130) of a transmission system (100) including a plurality of transmitters obtains equivalent circuit parameter values ​​(R, L, C) of transmitters (110-1, 110-2, 110-3, …) and a receiver (200) (S110).

[0070] The control unit (130) sets a transmission current of arbitrary size to be output from each transmitter while all of the multiple transmitters are in operation (S120). Each transmitter receives a transmission current of arbitrary size I from the control unit (130). TX It can receive a control signal that determines. Each transmitter uses a current mode converter to determine an arbitrary transmission current I set in that transmitter. TX While outputting, the input voltage V of the transmitter is determined by the input impedance TX It can be implemented to control.

[0071] The control unit (130) monitors the input voltage regulated to output the corresponding transmission current from each transmitter (S130).

[0072] The control unit (130) obtains the voltage and current of the receiver (S140). The transmitting system can monitor the voltage and current measured at the receiver in a specified manner (e.g., BLE communication).

[0073] The control unit (130) simultaneously tracks mutual inductances between multiple transmitters and receivers using equivalent circuit parameter values ​​of transmitters and receivers, a transmission current set in each transmitter and an input voltage monitored in each transmitter, and the voltage and current of the receiver (S150). In each mode classified according to the on / off status of the input voltage of each transmitter, the transmission current and reception current for each transmitter in that mode can be derived using an equation based on Kirchhoff's voltage law. Then, by superimposing the transmission currents and reception currents in each mode, an equation regarding the transmission currents and reception currents is derived. Here, using the equivalent circuit parameter values ​​of transmitters and receivers and the voltage and current obtained from transmitters and receivers, the unknown mutual inductances M1, M2, M3 and the load Z of the receiver L can be calculated.

[0074] As such, according to the present disclosure, mutual inductance can be measured without the need to repeatedly turn the power of the transmitter on and off, thereby increasing the stability of the three-dimensional wireless power charging system and also enabling high-speed measurement of mutual inductance.

[0075] According to the present disclosure, mutual inductance can be measured according to various states of the receiver, and can be utilized for wireless power charging of various devices.

[0076] The embodiments of the present disclosure described above are not implemented only through devices and methods, but may also be implemented through a program that realizes a function corresponding to the configuration of the embodiments of the present disclosure or a recording medium on which such program is recorded.

[0077] Although embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts of the present disclosure as defined in the following claims also fall within the scope of the present disclosure.

Claims

1. As a transmission system for three-dimensional wireless power charging, Multiple transmitters, and It includes a control unit that controls the plurality of transmitters mentioned above, and Each transmitter is It is implemented to receive a control signal determining a transmission current of arbitrary size from the above control unit, output the corresponding transmission current, and adjust the input voltage of the transmission unit by the input impedance of the transmission unit. The above control unit A transmission system implemented to monitor the input voltage of each transmitter and to track mutual impedances between the plurality of transmitters and receivers using data including the transmission current set in each transmitter and the input voltage monitored in each transmitter.

2. In Paragraph 1 Each transmitter is A transmission system comprising a current mode converter implemented to regulate the input voltage of the transmitting end by the input impedance of the transmitting end while outputting a transmission current set by the control unit.

3. In Paragraph 1 The above data A transmission system further comprising equivalent circuit parameter values ​​of the plurality of transmitters and the receiver, and the voltage and current of the receiver.

4. In Paragraph 3 The above control unit It is implemented to input values ​​included in the above data into equations regarding transmission currents and reception currents, and to calculate the mutual inductances and the load of the receiver, which are unknowns in the above equations, and The above equations are relationships derived by superimposing the transmission currents and reception currents in each mode classified according to the input voltage on / off of each transmitter, in a transmission system.

5. In Paragraph 1 The above control unit A transmission system implemented to acquire the data while all of the above-mentioned multiple transmitters are in operation.

6. In Paragraph 1 A transmission system in which the transmission coils of the plurality of transmitters are configured to be orthogonal to each other.

7. As a method of operation of a transmitting system for three-dimensional wireless power charging, A step of setting each transmitter to output a transmission current of arbitrary size while all multiple transmitters are in operation, A step of monitoring the input voltage regulated to output the corresponding transmission current at each transmitter, and A method of operation comprising the step of tracking mutual impedances between the plurality of transmitters and receivers using data including a transmission current set in each transmitter and an input voltage monitored in each transmitter.

8. In Paragraph 7 The step of obtaining equivalent circuit parameter values ​​of the plurality of transmitters and the receiver, and Step of obtaining the voltage and current of the above receiver A method of operation that further includes 9. In Paragraph 8 The above data A method of operation further comprising the above equivalent circuit parameter values, and the voltage and current of the receiver.

10. In Paragraph 9 The step of tracking the above mutual impedances Input the values ​​included in the above data into the equations regarding the transmission currents and reception currents, and calculate the mutual inductances and the load of the receiver, which are unknowns in the above equations, and The above equations are a method of operation in which the transmission currents and reception currents in each mode classified according to the input voltage on / off of each transmitter are derived by superimposing the equations.

11. In Paragraph 7 Each transmitter is A method of operation comprising a current mode converter implemented to adjust the input voltage of the transmitting end by the input impedance of the transmitting end while outputting a transmitting current set by the above-mentioned control unit.

12. In Paragraph 7 A method of operation in which the transmitting coils of the plurality of transmitters are configured to be orthogonal to each other.

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