Multi-emission-source wireless charging device

Abstract

The utility model relates to the field of wireless charging, in particular to a multi-transmitting-source wireless charging device, the primary side of the multi-transmitting-source wireless charging device is n transmitting ends, the secondary side of the multi-transmitting-source wireless charging device is a receiving end, and each transmitting end comprises a direct-current source module, a full-bridge inverter, a phase-shifting switched capacitor and a transmitting end coupling coil, the receiving end comprises a receiving end coupling coil, a series compensation circuit, a rectification filter circuit and a load, the receiving end and the transmitting end are respectively provided with a single chip microcomputer and a peripheral circuit thereof, and the peripheral circuit comprises a detection circuit, a driving circuit and a communication circuit; in the transmitting end, the output of the direct-current source module is connected with a full-bridge inverter, the output of the full-bridge inverter is connected with a phase-shifting switched capacitor, and the output of the phase-shifting switched capacitor is connected with a coupling coil of the transmitting end in series; in the receiving end, the receiving end coupling coil is connected in series with a compensation circuit and then connected with a rectification filter circuit, and the output end of the rectification filter circuit is connected with a load. The device is simple in structure and easy to implement, and the control method is effective and simple.

Description

Technical Field

[0001] The utility model relates to the field of wireless charging, and in particular to a multi-transmitter wireless charging device. Background Art

[0002] In magnetically coupled resonant wireless charging systems, the magnetic field strength generated by the coil is a key factor in measuring the system's transmission performance, and the uniformity of the magnetic field determines the stability of the entire charging process. Traditional single-transmitter wireless charging systems use only a single transmitting coil, and the magnetic field strength generated by the transmitting coil gradually decreases from the center of the coil outward. In actual operation, the coil is prone to significant offset, reducing the degree of magnetic field coupling, and the induced voltage generated on the receiving coil fluctuates significantly, affecting the system's transmission efficiency. For certain high-power applications, the power level of a single-transmitter system is limited, and the switching devices need to withstand greater voltage and current stress, which can easily damage the converter.

[0003] Multi-emitter wireless charging systems offer numerous advantages, including high flexibility, a large charging area, and uniform coil magnetic fields. Magnetic coupling resonant multi-emitter wireless charging systems, in particular, have been widely used in various fields due to their extended transmission distance and higher transmission efficiency. However, multi-emitter wireless charging systems still face some challenges. For example, Chinese utility model patent application number CN201710145547.4, titled "An Enhanced Wireless Charging System with Multiple Emitters," reduces direct coupling between the transmitting coils by providing a relay coil between the transmitting and receiving ends. This approach alleviates the cross-coupling issue to some extent, but also increases system complexity and places high demands on the precise positioning of devices. Chinese invention patent application number CN202111342014.8, titled "A Wireless Charging System and Resonant Network Matching Method Thereof," utilizes collected current and voltage data to derive phase difference data, thereby adjusting the PWM duty cycle of the primary and secondary series capacitors to maintain a resistive and resonant state for the wireless charging system. This method requires adjusting the capacitance values ​​of both the primary and secondary sides simultaneously. In addition, the control signal and current in the PWM-type switched capacitor are synchronized, requiring a corresponding zero-crossing detection circuit, making the control more difficult.

[0004] Therefore, it is necessary to design a multi-transmitter wireless charging device with a simple and effective control method to reduce the impact of cross-coupling between transmitting coils on the system transmission performance, improve the system transmission efficiency, and ensure the stability of the receiving end load output. Utility Model Content

[0005] The purpose of the utility model is to provide an efficient multi-transmitter wireless charging device on the basis of meeting power requirements.

[0006] In order to achieve the above purpose, the technical solution proposed by the utility model is:

[0007] A multi-transmitter wireless charging device has n transmitters on its primary side and one receiver on its secondary side. Each transmitter includes a DC source module, a full-bridge inverter, a phase-shifted switching capacitor, and a transmitter coupling coil. The receiver includes a receiver coupling coil, a series compensation circuit, a rectifier filter circuit, and a load. Both the transmitter and receiver have a single-chip microcomputer and its peripheral circuits, which include a detection circuit, a drive circuit, and a communication circuit.

[0008] At the transmitting end, the output of the DC source module is connected to a full-bridge inverter, the output of the full-bridge inverter is connected to a phase-shifted switching capacitor, and the output of the phase-shifted switching capacitor is connected in series with a transmitting end coupling coil; at the receiving end, the receiving end coupling coil is connected in series with a compensation circuit and then connected to a rectifier filter circuit, and the output of the rectifier filter circuit is connected to a load.

[0009] Furthermore, the phase-shifted switching capacitor includes two switching tubes Q1 and Q2 and two capacitors C1 and C2 with the same capacitance. A single switching tube and capacitor are connected in series to form a basic switching capacitor unit. Two basic switching capacitor units are connected in parallel to form a phase-shifted switching capacitor. The conduction states of the switching tubes Q1 and Q2 are always complementary.

[0010] Furthermore, the DC source module is used to output DC power, and has the following structure: the input end is connected in series with an NTC resistor, a rectifier bridge, and a fuse in sequence, wherein the output of the rectifier bridge is connected in series with a magnetic core and then in parallel with an output filter capacitor.

[0011] Furthermore, the full-bridge inverter is an H full-bridge, including a unidirectional full-bridge circuit consisting of four MOS transistors Q1-Q4 and four RCD snubber circuits. An RCD snubber circuit is connected in parallel to the D and S poles of each MOS transistor. The RCD snubber circuit is a diode and a resistor connected in parallel followed by a capacitor connected in series. In the unidirectional full-bridge circuit, MOS transistors Q1 and Q2 form a pair of bridge arms, namely the leading bridge arm, and MOS transistors Q3 and Q4 form another pair of bridge arms, namely the lagging bridge arm. The four MOS transistors are controlled by a microcontroller in combination with a drive circuit. MOS transistors Q1 and Q2 receive a set of complementary drive signals, and MOS transistors Q3 and Q4 receive another set of complementary drive signals. Phase shift control is adopted between the two bridge arms.

[0012] Furthermore, the rectifier and filter circuit includes a unidirectional bridge rectifier circuit composed of four diodes D1-D4 and a capacitor Co. In the unidirectional bridge rectifier circuit, diodes D1 and D2 form a pair of bridge arms, and diodes D3 and D4 form another pair of bridge arms. Capacitor Co is connected in parallel to the output end of the single-phase bridge rectifier circuit, wherein capacitor Co is an electrolytic capacitor with the positive pole connected to the high-voltage side of the output end.

[0013] Compared with the prior art, the utility model has the following advantages:

[0014] This device dynamically compensates for the negative impact of cross-coupling between transmitting coils on system transmission performance by adding compensating reactance to the transmitting circuit. Phase-shifting switched capacitors only require adjustment of the equivalent capacitance of the primary side. They are simple to implement and offer effective and simple control. Structurally, a single switching transistor and capacitor are connected in series to form a basic switched capacitor unit. Two such units connected in parallel can control the equivalent capacitance of the phase-shifting switched capacitor by controlling the shift angle between the switches.

[0015] The switch tube can realize soft switching, reduce loss, and the equivalent compensation capacitance value of the primary side of the switch tube can be obtained by calculating the mutual inductance value between the detection coils, thereby realizing dynamic compensation of the system and improving the transmission efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural block diagram of the multi-transmitter wireless charging device of the present invention;

[0017] Figure 2 This is a structural diagram of a DC input source module of a multi-transmitter wireless charging device of the present invention;

[0018] Figure 3 This is a structural diagram of a full-bridge inverter module of a multi-transmitter wireless charging device of the present invention;

[0019] Figure 4 This is a structural diagram of the receiving end of the multi-transmitter wireless charging device of the utility model;

[0020] Figure 5 This is a phase-shifted switched capacitor topology structure of the utility model;

[0021] Figure 6 This is the driving signal and working waveform diagram of the phase-shifted switched capacitor topology of the utility model;

[0022] Figure 7 This is the working mode diagram of the phase-shifted switched capacitor of the utility model.

[0023] Figure numerals: 1-DC source module, 2-full-bridge inverter, 3-phase-shifted switching capacitor, 4-transmitter coupling coil, 5-receiver coupling coil, 6-compensation circuit, 7-rectifier filter circuit, 8-load, 9-microcontroller and its peripheral circuits. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be further described below with reference to the accompanying drawings:

[0025] As attached Figure 1As shown, the multi-transmitter wireless charging device provided by the present invention has the following structure: its primary side has n transmitters and its secondary side has one receiver. The transmitter consists of a DC source module 1, a full-bridge inverter 2, a phase-shifted switched capacitor 3, and a transmitter coupling coil 4. The receiver consists of a receiver coupling coil 5, a compensation circuit 6, a rectifier and filter circuit 7, and a load 8. Furthermore, both the transmitter and receiver have a single-chip microcontroller and its peripheral circuitry 9. These peripheral circuits include a detection circuit, a drive circuit, and a communication circuit.

[0026] The transmitters of multi-source wireless charging devices all use the same hardware structure. Taking a single transmitter as an example, the output of the DC source module 1 is connected to a full-bridge inverter 2 to perform high-frequency DC inversion. The output of the full-bridge inverter 2 is connected to a phase-shifting switched capacitor 3, and the output of the phase-shifting switched capacitor 3 is connected in series with a transmitter coupling coil 4. Together, they form a transmitter resonant circuit, generating an AC-varying transmitter magnetic field. The transmitter coupling coil 4 couples with the receiver coupling coil 5 to complete energy transmission. The receiver coupling coil 5 is connected in series with a receiver compensation circuit 6 and then to a rectifier filter circuit 7. The receiver coupling coil 5 and the compensation circuit 6 form a receiver resonant circuit that receives energy transmitted by the resonant coupling magnetic field. The output of the receiver rectifier filter circuit 7 is connected to a load 8, which outputs DC power to power the load. It can also be connected to a battery to complete battery charging.

[0027] As attached Figure 2 As shown, the input current of DC source module 1 passes through an NTC resistor, a rectifier bridge, and a fuse. The output of the rectifier bridge is connected in series with a magnetic core and then in parallel with an output filter capacitor. The purpose of this module is to output stable DC power for use in a full-bridge inverter. The module input can be 220V AC or DC power.

[0028] The filter capacitor smoothes the output voltage. The NTC thermistor is used to suppress inrush current in the AC input circuit, and the series magnetic core can suppress the ripple component of the rectified DC power. Both can improve circuit reliability.

[0029] As attached Figure 3As shown, the full-bridge inverter module 2 is an H-type full-bridge, which, together with a phase-shifted switched capacitor 3 and a transmitter-side coupling coil 4, forms a resonant conversion module. The H-type full-bridge comprises a unidirectional full-bridge circuit consisting of four MOS transistors Q1-Q4 and four RCD snubber circuits. Each MOS transistor has an RCD snubber circuit connected in parallel between its D and S poles. The RCD snubber circuit, formed by a diode and a resistor connected in parallel and a capacitor connected in series, eliminates the voltage spike generated when the MOS transistor is turned off, ensuring proper operation. In the unidirectional full-bridge circuit, MOS transistors Q1 and Q2 form a pair of bridge arms (the leading arm), while MOS transistors Q3 and Q4 form another pair of bridge arms (the lagging arm). The four MOS transistors are controlled by a microcontroller in conjunction with a drive circuit. MOS transistors Q1 and Q2 receive one set of complementary drive signals, while MOS transistors Q3 and Q4 receive another set of complementary drive signals. Phase-shift control is employed between the two bridge arms.

[0030] After the full-bridge inverter module 2, the phase-shifted switching capacitor 3 and the transmitter coupling coil 4 together form a series resonant circuit, which is the transmitter resonant circuit.

[0031] Attachment Figure 4 This diagram shows the receiving end of the multi-transmitter wireless charging device of the present invention. The receiving end compensation circuit 6 includes a series CBB resonant capacitor. Together with the receiving end coupling coil 5, this circuit forms a series resonant circuit, the receiving end resonant circuit. Wireless energy transmission is achieved by utilizing the resonance between the transmitting and receiving end resonant circuits.

[0032] The receiving-end rectifier and filter circuit 7 is a unidirectional bridge rectifier circuit composed of four diodes D1-D4. It rectifies the high-frequency AC power received by the receiving-end resonant circuit. Diodes D1 and D2 form a pair of bridge arms, and diodes D3 and D4 form another pair of bridge arms. During the positive half-cycle, diodes D1 and D4 are in the on state, while diodes D2 and D3 are in the off state. At this time, the input current flows through the path of D1, the equivalent load, and D4, while also supplying energy to the equivalent load, thereby obtaining the rectified current during the positive half-cycle. Correspondingly, during the negative half-cycle, diodes D2 and D3 are on, while D1 and D4 are off. The current then flows through the path of D2, the equivalent load, and D3, and the equivalent load now receives the current for the other half-cycle. This process repeats continuously, thus achieving rectification. Capacitor Co is connected in parallel at the output end of the single-phase bridge rectifier circuit. Capacitor Co is an electrolytic capacitor, with the positive terminal connected to the high-voltage side of the output end. The DC power after voltage stabilization and filtering supplies power to the load.

[0033] Attachment Figure 5The topology of a phase-shifted switched capacitor 3 is shown, comprising two switching transistors (Q1, Q2) and two capacitors (C1, C2) of equal capacitance. The switching transistors and capacitors are connected in series to form a basic switched capacitor unit, with two such units connected in parallel to form a phase-shifted switched capacitor. In a phase-shifted switched capacitor, the conduction states of the switching transistors Q1 and Q2 are always complementary. By adjusting the phase difference between the switching transistor drive signal and the primary inverter leading bridge arm drive signal, the charging time of capacitors C1 and C2 is changed, thereby changing the equivalent capacitance of the phase-shifted switched capacitor.

[0034] The equivalent capacitance Ceq of the phase-shifting switching capacitor is proportional to its charge storage capacity. At the same time, the capacitances of the two capacitors are the same (C1=C2=C0). Therefore, the relationship between the phase shift angle θ and the equivalent capacitance Ceq of the phase-shifting switching capacitor is shown in formula (1.1), where the adjustment range of θ is [π / 4,π], and the corresponding equivalent capacitance adjustment range is: [C0,1.9239C0].

[0035]

[0036] Attachment Figure 6 The following is a typical waveform of a phase-shifted switched capacitor, where θ is the phase shift angle of the switch drive signal relative to the primary inverter S1 and S2. In the first row of the waveform, S1, S2, S3, and S4 are the serial numbers of the switch tubes in the full-bridge inverter, and in the second row, Q1 and Q2 are the serial numbers of the two switch tubes of the phase-shifted switched capacitor. The third and fourth rows are V AB 、i t The fifth to eighth rows are the voltage and current waveforms of the two branches of the phase-shifted switched capacitor.

[0037] Attachment Figure 7 The figure shows the working process of the phase-shifted switching capacitor in half a cycle of circuit modal analysis:

[0038] Phase 1 (t0-t1): At t0, Q2 turns on and Q1 turns off. At this point, the loop current is positive, and the current flows through Q2's antiparallel diode to charge capacitor C2.

[0039] Phase 2 (t1-t2): At t1, the input current crosses zero and reverses, the anti-parallel diode of Q2 is naturally turned off, and Q2 begins to conduct. At this time, the current i c2 is negative, capacitor C2 starts to discharge.

[0040] Phase 3 (t2-t3): At t2, capacitor C2 discharges until the voltage is equal to the voltage across capacitor C1, and the anti-parallel diode of Q1 is turned on. Since the capacitance values ​​of the two branches are the same, i c1 and i c2 Equal and equal to half of the input current.

[0041] The operating mode of the remaining half cycle is symmetrical with the first half cycle and is therefore not further analyzed. From the above analysis of the operating mode of the phase-shifted switched capacitor, it can be seen that during the operation of the phase-shifted switched capacitor, both MOSFETs in its circuit can achieve soft switching, indicating that the switching tube has low losses during the turn-on and turn-off processes.

[0042] The dynamic compensation cross-coupling process of the multi-emitter wireless charging device of the utility model is as follows: first, the input voltage and current are sampled by the detection circuit, and the detection circuit corresponds to the attached Figure 1 The single chip microcomputer and its peripheral circuit 9 process the sampled signals through the corresponding algorithm to obtain the fundamental component of the input voltage and current, and then use it to calculate the input impedance of the transmitting circuit. The input impedance is substituted into the mutual inductance related formula to obtain the reactance value that needs to be compensated. In this way, the phase difference between the switch tube drive signal and the primary inverter leading bridge arm drive signal is adjusted, thereby changing the equivalent capacitance of the phase-shifted switch capacitor to achieve the purpose of dynamic compensation.

[0043] The above description of the present invention and its embodiments is non-limiting. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, without inventive design, a structure and embodiment similar to the technical solution should fall within the scope of protection of the present invention.

Claims

1. A multi-source wireless charging device, characterized by: Its primary side is n transmitting ends, and its secondary side is a receiving end. Each transmitting end includes a DC source module (1), a full-bridge inverter (2), a phase-shifted switching capacitor (3) and a transmitting end coupling coil (4). The receiving end includes a receiving end coupling coil (5), a series compensation circuit (6), a rectifier filter circuit (7) and a load (8). Both the receiving end and the transmitting end have a single-chip microcomputer and its peripheral circuit (9). The peripheral circuit includes a detection circuit, a drive circuit and a communication circuit. At the transmitting end, the output of the DC source module (1) is connected to the full-bridge inverter (2), the output of the full-bridge inverter (2) is connected to the phase-shifting switch capacitor (3), and the output of the phase-shifting switch capacitor (3) is connected in series with the transmitting end coupling coil (4); at the receiving end, the receiving end coupling coil (5) is connected in series with the compensation circuit (6) and then connected to the rectifier filter circuit (7), and the output end of the rectifier filter circuit (7) is connected to the load (8).

2. The multi-transmitter wireless charging device according to claim 1, wherein: The phase-shifting switching capacitor (3) comprises two switching tubes Q1 and Q2 and two capacitors C1 and C2 of the same capacitance. A single switching tube and a capacitor are connected in series to form a basic switching capacitor unit. Two basic switching capacitor units are connected in parallel to form a phase-shifting switching capacitor (3). The conduction states of the switching tubes Q1 and Q2 are always complementary.

3. The multi-transmitter wireless charging device according to claim 2, wherein: The DC source module (1) is used for outputting DC power and has the following structure: an input end is connected in series with an NTC resistor, a rectifier bridge, and a fuse, wherein the output of the rectifier bridge is connected in series with a magnetic core and then in parallel with an output filter capacitor.

4. The multi-transmitter wireless charging device according to claim 3, wherein: The full-bridge inverter (2) is an H full-bridge, comprising a unidirectional full-bridge circuit consisting of four MOS tubes Q1-Q4 and four RCD buffer circuits. The D pole and S pole of each MOS tube are connected in parallel with an RCD buffer circuit. The RCD buffer circuit is a diode and a resistor connected in parallel and then connected in series with a capacitor. In the unidirectional full-bridge circuit, the MOS tubes Q1 and Q2 form a pair of bridge arms, namely the leading bridge arm, and the MOS tubes Q3 and Q4 form another pair of bridge arms, namely the lagging bridge arm. The four MOS tubes are controlled by a microcontroller in combination with a drive circuit. The MOS tubes Q1 and Q2 receive a set of complementary drive signals, and the MOS tubes Q3 and Q4 receive another set of complementary drive signals. A phase shift control method is adopted between the two bridge arms.

5. The multi-transmitter wireless charging device according to claim 4, wherein: The rectifier filter circuit (7) includes a unidirectional bridge rectifier circuit composed of four diodes D1-D4 and a capacitor Co. In the unidirectional bridge rectifier circuit, diodes D1 and D2 form a pair of bridge arms, and diodes D3 and D4 form another pair of bridge arms. The capacitor Co is connected in parallel to the output end of the single-phase bridge rectifier circuit. The capacitor Co is an electrolytic capacitor, and its positive electrode is connected to the high-voltage side of the output end.

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