Wireless charging apparatus and method
The wireless charging apparatus addresses instability in conventional systems by switching between dual frequencies with a high-order compensation network, ensuring reliable and efficient operation without sensors or communication, and adhering to industrial standards.
Patent Information
- Authority / Receiving Office
- HK · HK
- Patent Type
- Applications
- Current Assignee / Owner
- THE HONG KONG POLYTECHNIC UNIV
- Filing Date
- 2026-05-27
- Publication Date
- 2026-07-10
AI Technical Summary
Conventional wireless charging systems are prone to failure due to environmental interference, power supply issues, and compatibility problems, leading to unsafe and unstable operation by relying on sensors and communication components.
A wireless charging apparatus with automatic switching between dual operating frequencies using a high-order compensation network at both the transmitting and receiving ends, eliminating the need for sensing and communication components, and ensuring compliance with industrial frequency bands.
Ensures high reliability and stable operation by adapting to charging curves of power batteries, supporting bidirectional energy flow, and reducing component count.
Smart Images
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Abstract
Description
English Abstract Title: Wireless Charging Apparatus and Method Abstract: The present application discloses a sensorless wireless charging apparatus and method. Conventional wireless charging systems rely on sensors to achieve real-time monitoring of various charging parameters at both the energy transmitting end and the energy receiving end, and to complete data transmission and reception via certain communication methods. However, due to environmental interference, power supply failures, and compatibility issues, the sensing and communication functions are prone to failure, resulting in unsafe and unstable operation of the wireless charging system. To address this problem, the present application proposes a wireless charging apparatus with automatic switching between dual operating frequencies based on a high-order compensation network at both the transmitting and receiving ends, and a corresponding dual-operating-frequency switching charging method that adapts to the charging curve of power batteries. The said wireless charging apparatus not only eliminates dependence on sensing and communication components so that high reliability can be achieved, but also ensures that the selected operating frequencies complies with industrial standard frequency bands. Furthermore, it offers competitive advantages such as supporting bidirectional energy flow, achieving zero-phase-angle high-efficiency operation, and reducing the number of components in the wireless charging apparatus. Abstract
Claims
1. A wireless charging device, comprising a primary-side energy transmitter and a secondary-side energy receiver, in, The primary side energy transmitter includes a primary side energy transmitter coil, a primary side compensation network, and a primary side power converter. The secondary side energy receiver includes a secondary side energy receiver coil, a secondary side compensation network, and a secondary side power converter. However, the secondary side energy receiver does not include a sensor for detecting the charging status of the load device. The primary-side power converter is connected to the input power supply, the secondary-side power converter is coupled to the load device to charge it, and the primary-side energy transmitting coil and the secondary-side energy receiving coil transmit energy wirelessly through mutual inductance. The primary-side power converter converts the input power into AC voltage and provides the AC voltage to the primary-side compensation network. The primary-side compensation network transmits the AC voltage to the primary-side energy transmitting coil after resonant transformation. The primary-side energy transmitting coil induces an AC voltage in the secondary-side energy transmitting coil wirelessly through mutual inductance and transmits the AC voltage to the secondary-side compensation network. After resonant transformation by the secondary-side compensation network, the AC voltage is provided to the secondary-side power converter, which then converts it into a DC output voltage for charging the load equipment.
2. The wireless charging device according to claim 1, wherein the input power supply is an input DC power supply, the primary-side power converter includes a primary-side inverter containing switching devices, and the secondary-side power converter includes a rectifier containing switching devices.
3. The wireless charging device according to claim 1, wherein the structures of the primary-side energy transmitter and the secondary-side energy receiver are symmetrical, the inductance value of the energy transmitting coil in the primary-side energy transmitter is consistent with the inductance value of the energy receiving coil in the secondary-side energy receiver, the topology and inductance / capacitance values of the compensation network of the primary-side energy transmitter are consistent with the topology and inductance / capacitance values of the compensation network of the secondary-side energy receiver, and both the power converter of the primary-side energy transmitter and the power converter of the secondary-side energy transmitter use fully controlled switching devices to enable the wireless charging device to achieve bidirectional energy flow.
4. The wireless charging device according to claim 3, wherein the primary-side compensation network and the secondary-side compensation network are in a CLC-CLC or LCC-LCC symmetrical form, wherein, C represents the compensation capacitor, and L represents the compensation inductor.
5. The wireless charging device according to claim 3, wherein the inverter at the primary side energy transmitter or the rectifier at the secondary side energy receiver each comprises only one stage converter.
6. The wireless charging device according to claim 1, wherein the wireless charging device is configured to charge the load device through a constant current-constant voltage two-stage charging process. in, The first stage of the charging process is constant current charging. The operating frequency of the primary side energy transmitter is the constant current operating frequency. The secondary side power converter charges the load device with a constant current. In the first stage, the input current of the primary side compensation network will increase with the increase of the charging voltage of the secondary side power converter. The wireless charging device determines whether the input current has increased to the mode switching point. as well as, When the input current increases to the mode switching point, the operating frequency of the primary side energy transmitter switches from constant current operating frequency to constant voltage operating frequency, and the charging process of the wireless charging device enters the second stage. The second stage is constant voltage charging, which is performed at a constant voltage operating frequency. The charging voltage of the secondary side power converter remains constant, while the charging current of the primary side compensation network gradually decreases. The wireless charging device determines whether the input current of the primary side compensation network has decreased to the charging stop point. When the input current decreases to the charging stop point, the charging process ends.
7. The wireless charging device according to claim 6, wherein the mode switching point of the input current is associated with the battery characteristics of the load device and the impedance characteristics of the wireless charging device.
8. A wireless charging system, the wireless charging system comprising a wireless charging device according to any one of claims 1-6 and a control device, wherein the control device comprises an input voltage and current sampling circuit, a controller and a drive circuit, the controller comprising a charging parameter setting module and a mode switching module, the charging parameter setting module setting or pre-setting parameters for switching the operating frequency of the wireless charging device, including a constant current operating frequency, a constant voltage operating frequency, a mode switching point and a charging stop point, and the mode switching module switching the charging mode of the wireless charging device from a constant current charging mode to a constant voltage charging mode based on the mode switching point and the charging stop point.
9. A charging method for a wireless charging device, the charging method charging the load device through a constant current-constant voltage two-stage charging process, the charging method comprising: (1) The first stage of the charging process is constant current charging. The operating frequency of the primary side energy transmitter of the wireless charging device is the constant current operating frequency. The secondary side power converter of the wireless charging device charges the load device with a constant current. In the first stage, the input current of the primary side compensation network in the primary side energy transmitter will increase with the increase of the charging voltage of the secondary side power converter. In the first stage of the charging process, it is determined whether the input current increases to the mode switching point. as well as, (2) When the input current increases to the mode switching point, the operating frequency of the primary side energy transmitter switches from constant current operating frequency to constant voltage operating frequency, and the charging process of the wireless charging device enters the second stage. The second stage is constant voltage charging, which is performed at a constant voltage operating frequency. The charging voltage of the secondary side power converter remains constant, while the charging current of the primary side compensation network gradually decreases. In the second stage of the charging process, it is determined whether the input current of the primary side compensation network has dropped to the charging stop point. When the input current drops to the charging stop point, the charging process ends.
10. The charging method according to claim 9, wherein, The mode switching point of the input current is related to the battery characteristics and the impedance characteristics of the wireless charging device, and the mode switching point and the charging stop point are determined by the following steps: The parameters X of each compensation element in the primary-side compensation network and the secondary-side compensation network of the wireless charging device are... t1 To X t4 X r1 To X r4 The values of mutual inductance M and the resistance R of the load device are input into the following formulas (1), (2), (3), and (4) to solve for parameters A and B: The current gain of the wireless charging device relative to the input voltage of the primary-side compensation network is expressed by formula (1): In formula (1), X = -jω cc MX t3 X r3 , Y1=(ω cc M) 2 (X t3 +X t4 )[jR-(X r3 +X r4 )], Y2=[(X t1 +X t2 )(X t3 +X t4 )+X t3 X t4 ], Y3=[j(X r1 +X r2 +X r3 )R-(X r1 +X r2 )(X r3 +X r4 )-X r3 X r4 ], M represents the mutual inductance between the primary and secondary energy emitting coils. R represents the resistance of the load device. Among them, jX ti (i = 2, 3, 4) represent the compensation elements L1, C1, C2, and C3 of the primary compensation network. t The impedance form, jX ri (i = 2, 3, 4) represents the compensation element C of the secondary side compensation network. r The impedance forms of C2 and L2, and the compensation elements in the primary and secondary compensation networks are arranged in a T-type equivalent network form, jX t1 and jX r1 Let i represent the impedances of the primary and secondary energy transmitting coils of the wireless charging device, respectively, and define the index i∈{1,2,3,4}: The simplified form of formula (1) is: The voltage gain of the wireless charging device relative to the input voltage is expressed by formula (3): In formula (3), X = -jω cv MX t3 X r3 R, Y4=(ω cv M) 2 (X t3 +X t4 )[jR-(X r3 +X r4 )], Y5=[(X t1 +X t2 )(X t3 +X t4 )+X t3 X t4 ], Y6=[j(X r1 +X r2 +X r3 )R-(X r1 +X r2 )(X r3 +X r4 )-X r3 X r4 ], The simplified form of formula (3) is: Solve for the constant current operating frequency, which makes |B / A| in formula (2) take the minimum value; solve for the constant voltage operating frequency, which makes |A / R| / |B / R| in formula (4) take the minimum value, thereby determining the constant current operating frequency and the constant voltage operating frequency respectively; Then, based on the battery characteristics of the load device, the optimal switching load for constant current charging mode and constant voltage charging mode is determined, and the input current of the primary-side energy emitter corresponding to this switching load is marked as the mode switching point for constant current charging and constant voltage charging; and The equivalent load at which the battery is fully charged is determined based on the battery characteristics, and the input current at the primary side energy emitter corresponding to the equivalent load is marked as the charging stop point.