CN207410122U - Magnetic resonance is wireless MISO charging circuits - Google Patents

Abstract

The utility model provides a magnetic resonance wireless MISO charging circuit, which is composed of a power supply module S1, a DDS signal generation module S2, an impedance measurement module S3, an impedance matching module S4, a transceiver coil module S5 and a receiving circuit to supply power to a load module S6, a transceiver coil module S5 includes two or more transmitting coils S51 and a receiving coil S52, the receiving coil S52 is connected to the load power supply module S6; the DDS signal generation module S2 is provided with a DDS signal generator corresponding to each transmitting coil S51 respectively; the impedance measurement module S3 includes and each The transmitting coils S51 respectively correspond to impedance measuring circuits, the impedance matching module S4 includes impedance matching circuits corresponding to each transmitting coil S51, and the impedance matching circuit corresponding to each transmitting coil S51 includes two different types of impedance matching networks, two different Type impedance matching networks are respectively connected to the corresponding transmitting coils S51.

Description

Magnetic resonance wireless MISO charging circuit

technical field

The utility model relates to the technical field of magnetic resonance wireless charging, in particular to a magnetic resonance wireless MISO charging circuit.

Background technique

Magnetic resonance wireless charging technology is one of the mainstream technologies of wireless charging, which has the advantages of long transmission distance and high efficiency. With the release of the WPC1.2 specification, the current market has begun to shift from magnetic induction technology to magnetic resonance wireless charging technology, which is mainly aimed at charging mobile smart devices, wearable devices, and low-power small devices. Magnetic resonance wireless charging technology products can be made into a charging board (containing single or multiple coil transmitters), which can charge multiple receiving devices at the same time, becoming the future development direction of the wireless charging market. The charging efficiency of the charging receiving device is closely related to the position from the charging board. The charging board is a transmitting end composed of multiple coils, and each coil has a different degree of magnetic induction with the receiving device in the effective charging area. In order to better manage multi-device wireless charging, it is necessary to propose a wireless charging circuit design scheme to make the wireless charging system more intelligent, efficient and safe.

At present, wireless charging technology mainly includes four basic methods: electromagnetic induction, magnetic resonance, electric field coupling, and radio wave. At present, the most mature and common one is the electromagnetic induction type. Its technology is to apply the principle of electromagnetic induction. The alternating current flows through the transmitter coil to generate a changing magnetic field, and the transmitter coil generates current under the changing magnetic field to charge the receiving device. . Magnetic resonance technology also applies the principle of electromagnetic induction, and the frequency of the transmitting end and the receiving end are the same to achieve a resonance effect to enhance transmission efficiency. The principle of electric field coupling technology is to transfer the electric energy from the transmitting end to the receiving end through the electric field, and use the induced electric field generated by two groups of asymmetric dipoles coupled in the vertical direction to transmit electric energy. The principle of radio wave technology is to convert electromagnetic waves into current and transmit current through circuits, but it has disadvantages such as small transmission distance, low conversion efficiency, and large radiation.

The principle of various charging boards such as star-shaped wireless charging boards and Apple watch wireless chargers is basically electromagnetic induction charging, and the charging equipment and charging boards need to be bonded together. The research direction of large companies has turned to charging boards that can charge multiple mobile devices in any direction and within an appropriate distance. The existing adhesive wireless charging products cannot meet people's needs.

Since the multi-device wireless charging technology has only started research at home and abroad in the past few years, the future application fields are mainly mobile smart devices, wearable devices, small low-power devices, etc. Starting from the circuit design of the wireless charging system, there are currently the following papers and patents:

The paper (Wireless Power Hotspot that Charges All of Your Devices) described an example of a multi-coil charging board charging multiple devices under the condition of magnetic resonance. The receiving device and the charging board (transmitter) have the same coil frequency. In order to achieve resonance to improve charging efficiency. In this paper, the transmitting end and the receiving end use in-band communication to transfer information, estimate each channel, and then use the maximum power transmission algorithm to control the voltage of the transmitting end coil. This example gave us the direction of research reference and confirmed the feasibility of multi-device wireless charging, but in the management of the charging system due to the waste of resources caused by load mismatch and the complex circuit structure, there is a lot of room for optimization that needs our further research. Research and explore.

Patent (CN104701955A) discloses a wireless charging device connected with a charging stand and a battery. By sequentially connecting the oscillation module, the rectification and step-down module and the power management module, the Bluetooth communication module is connected to the rectification and step-down module, and the power management module is connected to the battery. The Bluetooth communication module communicates with the charging stand to obtain the charging communication protocol. The oscillation module receives the signal from the charging stand and oscillates to generate alternating current. The rectification and step-down module rectifies and steps down the alternating current and outputs a DC reference voltage. The power management module After the reference voltage is stepped down, the charging voltage is output to charge the battery. The circuit design of this patent is relatively complicated, and further research and exploration are still needed in the design process of multi-coil wireless charging.

It can be seen that since the single wireless charging technology has been relatively mature, many companies at home and abroad have been researching the multi-device wireless charging technology. The existing papers and patents only propose some simple solutions in the charging scheme, and some of them have A charging method based on multiple coils is proposed. However, the current multi-coil charging design circuit is too complex, especially at the receiving end of the circuit, it is necessary to design additional circuit detection and information feedback functions, which increases the complexity and cost of the circuit.

Utility model content

The purpose of the utility model is to design a wireless charging system circuit based on magnetic coupling resonance in combination with the feasibility of multi-device wireless charging.

The technical solution adopted by the utility model includes a magnetic resonance wireless MISO charging circuit, which is composed of a power supply module S1, a DDS signal generation module S2, an impedance measurement module S3, an impedance matching module S4, a transceiver coil module S5 and a receiving circuit to supply power to the load module S6 composition,

The power supply module S1 is connected to the signal generation module S2, the signal generation module S2 is connected to the impedance measurement module S3, the impedance measurement module S3 is connected to the impedance matching module S4, the impedance matching module S4 is connected to the transceiver coil module S5, and the transceiver coil module S5 is connected to the receiving circuit to the load power supply module S6;

The transceiver coil module S5 includes two or more transmitting coils S51 and one receiving coil S52, and the receiving coil S52 is connected to the load power supply module S6;

The DDS signal generation module S2 is provided with a DDS signal generator corresponding to each transmitting coil S51 respectively;

The impedance measurement module S3 includes impedance measurement circuits respectively corresponding to each transmitting coil S51;

The impedance matching module S4 includes an impedance matching circuit corresponding to each transmitting coil S51. The impedance matching circuit corresponding to each transmitting coil S51 includes two different types of impedance matching networks, and the two different types of impedance matching networks are respectively connected to the corresponding transmitting coils. Coil S51.

Moreover, the impedance measurement circuit corresponding to each transmitting coil S51 is composed of a directional coupler S31, an attenuator S32, a detection chip S33 and a selection chip S34,

The input terminal of the directional coupler S31 is connected to the signal generation module S2, and the through terminal of the directional coupler S31 is connected to the impedance matching module S4. The incident wave signal at the input terminal of the directional coupler S31 is coupled to the coupling terminal, and the signal at the through terminal of the directional coupler S31 passes through the receiving coil After S52, a reflected signal is formed, and the reflected signal is coupled to the isolation terminal;

The two attenuators S32 are respectively connected to the coupling end and the isolation end of the directional coupler S31 for adjusting the input signal of the detection chip S33;

The two power attenuation ports of the detection chip S33 are respectively connected to the signal adjusted by the attenuator S32, the detection chip S33 outputs the voltage gain through the gain port, and outputs the voltage phase through the phase port;

The selection chip S34 receives the voltage gain and the voltage phase, outputs a selection signal to the corresponding impedance matching circuit of the transmitting coil S51, and connects to one of two different types of impedance matching networks.

Moreover, the receiving circuit power supply module S6 for the load is composed of a full bridge rectifier circuit S61, a filter circuit S62 and a voltage stabilizing circuit S63 connected in sequence.

Moreover, the impedance matching circuit corresponding to each transmitting coil S51 includes an L-shaped impedance matching network and an inverse L-shaped impedance matching network.

Alternatively, the impedance matching circuit corresponding to each transmitting coil S51 includes a T-type impedance matching network and a π-type impedance matching network.

According to the characteristics of wireless energy transmission, the utility model designs a circuit of a wireless charging system, improves the efficiency of wireless charging through impedance matching and power control; provides a feasible reference scheme for multi-device wireless charging, facilitates systematic and integrated manufacturing, and provides future The realization of product commercialization provides a feasible basis and has important market value.

The utility model has the following advantages:

(1) The design of the wireless charging circuit of the present utility model is not limited to two transmitting coils, and is equally applicable to the design of a wireless charging circuit with multiple transmitting coils;

(2) The input impedance of the utility model is obtained by the detection chip, which reduces the complexity of circuit design;

(3) The impedance matching network proposed by the present invention is not limited to L-type and reverse-L-type impedance matching, and can also be replaced by T-type and π-type impedance matching networks.

Description of drawings

FIG. 1 is a structural diagram of a wireless charging circuit according to an embodiment of the present invention.

FIG. 2 is a structural diagram of an impedance measurement circuit according to an embodiment of the present invention.

FIG. 3 is an equivalent circuit diagram of wireless charging according to an embodiment of the present invention.

FIG. 4 is a structural diagram of an L-shaped and an inverted L-shaped impedance matching network according to an embodiment of the present invention.

FIG. 5 is a structural diagram of a transceiver coil module according to an embodiment of the present invention.

FIG. 6 is a structural diagram of a receiving circuit power supply module for a load according to an embodiment of the present invention.

Fig. 7 is a structural diagram of a model of a 2-to-1 wireless charging system according to an embodiment of the present invention.

Detailed ways

The technical solution of the utility model will be clearly and completely described below in conjunction with the accompanying drawings and embodiments.

Referring to Fig. 1, the magnetic resonance wireless MISO charging circuit provided by the present invention has 6 parts: power supply module S1, DDS signal generation module S2, impedance measurement module S3, impedance matching module S4, transceiver coil module S5 and receiving circuit power supply module for the load S6. Among them, MISO means multiple transmit single receive.

The transceiver coil module S5 includes two or more transmitting coils S51 and one receiving coil S52, and the receiving coil S52 is connected to the load power supply module S6;

The DDS signal generation module S2 is provided with a DDS signal generator corresponding to each transmitting coil S51 respectively;

The impedance measurement module S3 includes an impedance measurement circuit corresponding to each transmitting coil S51, and the impedance measurement circuit corresponding to each transmitting coil S51 includes a directional coupler S31, an attenuator S32, a detection chip S33 and a comparator S34,

The impedance matching module S4 includes an impedance matching circuit corresponding to each transmitting coil S51. The impedance matching circuit corresponding to each transmitting coil S51 includes two different types of impedance matching networks, and the two different types of impedance matching networks are respectively connected to the corresponding transmitting coils. Coil S51.

The power supply module S1 is connected to the signal generation module S2, the signal generation module S2 is connected to the impedance measurement module S3, the impedance measurement module S3 is connected to the impedance matching module S4, the transceiver coil module S5 is connected to the impedance matching module S4, and the transceiver coil module S5 is connected to the receiving circuit to the load power supply module S6;

The power supply module S1 transmits the electric energy provided by the power supply to the signal generation module S2;

The signal generation module S2 transmits the signal carrying electric energy to the impedance measurement module S3, which will be described in detail next;

The impedance matching module S4 provides a variety of different input impedance matching networks for the selection of the impedance measurement module S3, which will be described in detail next;

The transceiver coil module S5 is connected to the impedance matching module S4 to couple the signal energy to the receiving end circuit;

The receiving circuit supplies the load power supply module S6 with the energy coupled from the transceiver coil module S5, and supplies power to the load through rectification, filtering and voltage stabilization. This module will be described in detail next.

Referring to Fig. 2, each impedance measurement circuit includes a directional coupler S31, an attenuator S32, a detection chip S33 and a comparator S34,

The impedance measurement device uses a directional coupler S31, which includes an input terminal, a straight-through terminal, a coupling terminal and an isolation terminal.

The input terminal of the directional coupler S31 is connected to the signal generating module S2, the through terminal of the directional coupler S31 is connected to the impedance matching module S4, the incident wave signal Vinc at the input terminal of the directional coupler S31 is coupled to the coupling terminal Vcoup, and the through terminal Vtran of the directional coupler S31 is The signal forms a reflected signal Vref after passing through the LC resonant coil (the receiving coil in the transceiver coil module S5), and the formed reflected signal Vref is coupled to the isolation terminal Viso.

The two attenuators S32 are respectively connected to the coupling end and the isolation end of the directional coupler S31 to adjust the size of the input signal of the detection chip S33. The two attenuators are respectively marked as attenuator A and attenuator B in the figure, respectively Into the two power attenuation ports of the detection chip S33;

The detection chip S33 is AD8302, which has 4 ports, among which the A and B channels are power attenuation ports, respectively connected to the signal adjusted by the attenuator S32, the detection chip S33 converts the received electrical signal into a voltage signal, and passes through the gain port Output voltage gain, output voltage phase through the phase port;

The selection chip S34 receives the voltage gain and the voltage phase, and outputs a selection signal to the impedance matching module S4. The optional chip S34 can use an MCU controller, such as arduino uno3, which supports user setting and use. It can calculate the amplitude ratio of the two signals according to the voltage and signal at the gain end of the detection chip S33, and calculate the amplitude ratio of the two signals according to the voltage and phase signal at the phase end of the detection chip S33. , calculate the phase difference of the two signals. From the amplitude ratio and phase difference of the two signals, the emission coefficient Γ can be calculated. then by the formula Then the input impedance can be calculated, where Z ₀ =50Ω is the signal source impedance, and Z _L is the input. impedance. In order to save costs, the impedance measurement circuits of each transmitting coil S51 can be integrated into one chip. In the embodiment, the two impedance measurement circuits share one arduino uno3 chip.

See the equivalent circuit diagram of wireless charging in Figure 3. Z ₀ in the figure is the equivalent impedance of the signal source V _S , that is, the output impedance of the signal source; Z _L is the equivalent impedance of the output circuit, that is, the input impedance, and R _L is the load power resistance. When the output impedance does not match the input impedance, an impedance matching network is introduced at the front end of the transmitting coil. For example, when R is greater than 50 ohms, an L-type impedance matching network is selected, otherwise an inverse L-type impedance matching network is selected. After the impedance measurement module S3 detects the amplitude and phase value of the signal through the AD8302 amplitude and phase detection chip and calculates the data of the input impedance value through the arduino uno3, it starts to select the impedance matching network. Existing technologies can be used for specific detection and calculation, and those skilled in the art can set them according to their needs.

Referring to FIG. 3 , the L-type and reverse-L-type impedance matching network structure in the impedance matching module S4 of the embodiment, the selection chip S34 outputs a selection signal to the impedance matching module S4, and the L-type or reverse-L-type impedance matching network structure is connected. Where jX is the equivalent inductive reactance of the impedance matching network, 1/jB is the equivalent capacitive reactance of the impedance matching network, assuming that the input impedance value calculated by the impedance measurement module S3 is Z _L =R+jX, wherein R is the real part, X is the imaginary part.

In the radio frequency and microwave frequency bands, in order to maximize energy transmission, an impedance matching circuit is designed to ensure that the input and output impedances of the source are equal. In the embodiment, when the signal generator is tuned to a certain frequency, since its equivalent impedance is 50Ω, the input impedance of the transmitting end is also adjusted to 50Ω through the impedance matching circuit. Therefore, it can be preset by the user:

When the real part of the input impedance satisfies R>50Ω (S41), the output selection signal selects the L-type impedance matching network S42. Since the L-shaped impedance matching network S42 can reduce the value of the real part R, its impedance can be matched to the same value as the source impedance 50Ω, so as to achieve the purpose of impedance matching and realize the maximum energy transmission;

When the real part of the input impedance does not satisfy R>50Ω (S41), select an inverse L-shaped impedance matching network S43. Since the reverse L-shaped impedance matching network S43 can reduce the value of the real part R, its impedance can be matched to the same value as the source impedance 50Ω, so as to achieve the purpose of impedance matching and realize energy maximization transmission;

Finally, the L-shaped impedance matching network S42 or the reverse L-shaped impedance matching network S43 transmits energy through the transceiver coil module S5.

Referring to Fig. 5, the transceiving coil module S5 of the embodiment includes two transmitting coils S51 and one receiving coil S52, the two transmitting coils are in a circular structure with an outer diameter of 12 cm, an inner diameter of 9 cm, and impedance values of 10+0.32j , respectively recorded as TX1 and TX2, the receiving coil adopts the square coil of nucurrent company, the outer diameter is 7cm long, the outer diameter width is 5.6cm, the inner diameter is 4.5cm long, the inner diameter width is 3.2cm, and the impedance is 4.64+0.15j, Denoted as RX; in the transmitting end circuit (S1~S4), the transmitting end signal is transmitted to the transmitting coil TX1 and TX2 after impedance matching, and then transmitted to the load (S6 and user load) after being received by the receiving coil RX, and the receiving coil RX is received terminal LC resonant coil.

Accompanying drawing 6 is the structural diagram of the receiving circuit supplying power to the load module, which is composed of a full-bridge rectifier circuit S61, a filter circuit S62 and a voltage stabilizing circuit S63 connected in sequence.

The energy coupled by the transceiver coil module S5 is an AC signal, which is converted into a DC signal that can supply power to user loads through the full-bridge rectifier circuit S61;

The signal after high-frequency rectification by the full-bridge rectifier circuit S61 has not only a DC signal component, but also an AC component. The filter circuit S62 can effectively filter out the AC component after high-frequency rectification by the full-bridge rectifier circuit S61;

Although the filter circuit S62 filters out the AC component, it is accompanied by a certain harmonic component, and the influence of the harmonic component on the circuit needs to be eliminated by the voltage stabilizing circuit S63 to provide a stable voltage for the load.

Referring to FIG. 7 , the embodiment adopts a 2-to-1 wireless charging system, that is, a 2-to-1 wireless charging system with two transmitting coils and one receiving coil.

The power module supplies power to other modules and provides energy for the system;

The DDS signal generation module S2 includes two DDS signal generators, which provide signals for the system, amplify the AC signal carrying energy through the power amplifier, transmit it to the impedance matching network, and then transmit it to the transmitting coils TX1 and TX2; the receiving coil RX is used to receive and transmit The AC energy signal carried by the coils TX1 and TX2 is transmitted to the load to supply power to the load; the AD8302 detection module is used to detect the amplitude and phase of the signal amplified by the power amplifier, and then read the amplitude and phase detected by AD8302 through arduino uno3 and calculate the value of the input impedance. According to the value of input impedance, choose L-type or reverse-L-type impedance matching network.

The product of the utility model is suitable for manufacture and sale. During specific implementation, it is preferred that the manufacturer select a high-efficiency power amplifier according to the power required by the load, and determine the size of the power supply that needs to be powered by the conversion efficiency of the power amplifier. In order to realize the maximum energy transmission of the power supply, the input impedance can be measured by using the impedance measurement module of the utility model, and the corresponding impedance matching network is matched according to the measured input impedance value, so that the equivalent impedance of the signal source is equal to the load The end impedances are equal, and then coupled to the receiving end through the transceiver coil. After rectification, filtering and voltage stabilization at the receiving end, the received energy is supplied to the load.

The specific embodiments described herein are only examples to illustrate the spirit of the present invention. Those skilled in the technical field to which the utility model belongs can make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, but they will not deviate from the spirit of the utility model or go beyond the appended claims defined range.

Claims (5)

1. A magnetic resonance wireless MISO charging circuit is characterized in that: it is composed of power supply module S1, DDS signal generation module S2, impedance measurement module S3, impedance matching module S4, transceiver coil module S5 and receiving circuit to load power supply module S6, The power supply module S1 is connected to the signal generation module S2, the signal generation module S2 is connected to the impedance measurement module S3, the impedance measurement module S3 is connected to the impedance matching module S4, the impedance matching module S4 is connected to the transceiver coil module S5, and the transceiver coil module S5 is connected to the receiving circuit to the load power supply module S6; The transceiver coil module S5 includes two or more transmitting coils S51 and one receiving coil S52, and the receiving coil S52 is connected to the load power supply module S6; The DDS signal generation module S2 is provided with a DDS signal generator corresponding to each transmitting coil S51 respectively; The impedance measurement module S3 includes impedance measurement circuits respectively corresponding to each transmitting coil S51; The impedance matching module S4 includes an impedance matching circuit corresponding to each transmitting coil S51. The impedance matching circuit corresponding to each transmitting coil S51 includes two different types of impedance matching networks, and the two different types of impedance matching networks are respectively connected to the corresponding transmitting coils. Coil S51. 2. The magnetic resonance wireless MISO charging circuit according to claim 1, characterized in that: each transmitting coil S51 corresponding impedance measurement circuit is composed of a directional coupler S31, an attenuator S32, a detection chip S33 and a selection chip S34, The input terminal of the directional coupler S31 is connected to the signal generation module S2, and the through terminal of the directional coupler S31 is connected to the impedance matching module S4. The incident wave signal at the input terminal of the directional coupler S31 is coupled to the coupling terminal, and the signal at the through terminal of the directional coupler S31 passes through the receiving coil After S52, a reflected signal is formed, and the reflected signal is coupled to the isolation terminal; The two attenuators S32 are respectively connected to the coupling end and the isolation end of the directional coupler S31 for adjusting the input signal of the detection chip S33; The two power attenuation ports of the detection chip S33 are respectively connected to the signal adjusted by the attenuator S32, the detection chip S33 outputs the voltage gain through the gain port, and outputs the voltage phase through the phase port; The selection chip S34 receives the voltage gain and the voltage phase, outputs a selection signal to the corresponding impedance matching circuit of the transmitting coil S51, and connects to one of two different types of impedance matching networks. 3. The magnetic resonance wireless MISO charging circuit according to claim 1, wherein the receiving circuit power supply module S6 for the load is composed of a full-bridge rectifier circuit S61, a filter circuit S62 and a voltage stabilizing circuit S63 connected in sequence. 4. The magnetic resonance wireless MISO charging circuit according to claim 1, 2 or 3, wherein the impedance matching circuit corresponding to each transmitting coil S51 includes an L-shaped impedance matching network and an inverse L-shaped impedance matching network. 5. The magnetic resonance wireless MISO charging circuit according to claim 1, 2 or 3, characterized in that: the impedance matching circuit corresponding to each transmitting coil S51 includes a T-type impedance matching network and a π-type impedance matching network.