CN107579601B - Wireless Energy Transmission Device - Google Patents

Abstract

A wireless energy transmission device, which includes: a capacitor matrix, a detection circuit, a relay system, an oscillator and a single-chip control unit, the single-chip control unit is set to control the oscillator to make the operating frequency of the excitation power scan and change, and can control the relay system to make the transmission The natural frequency scanning changes of the loop can record the magnitude and frequency of each output current when the output voltage and output current are in phase, and can select the frequency of the minimum output current among the recorded output currents, and can also make the operating frequency of the excitation power supply and emission The natural frequencies of the loops are all the same as the frequency of this minimum output current. The device of the invention only needs to install a control device at the transmitting end of the system, so that both the operating frequency of the excitation power supply and the natural frequency of the transmitting loop can be scanned and changed, and the natural frequency of the receiving loop can be dynamically tracked, so as to realize the resonance work of the whole system.

Description

Wireless Energy Transmission Device

technical field

The present invention relates to the technical field of wireless energy transmission, in particular to a wireless energy transmission device and a method for controlling the resonant frequency of the device.

Background technique

Various electrical devices usually use wired connections to achieve energy transmission. Because the wireless transmission of energy has the characteristics of safety and convenience, realizing the wireless transmission of energy has always been a dream that people are eager to realize. In some special applications, such as underwater operations, medical implants, wireless networks and other occasions where it is inconvenient or impossible to use wires to provide energy, wireless energy transmission has a high application value.

According to the principle of energy transmission, at present, the wireless energy transmission technology researched at home and abroad mainly includes electromagnetic wave energy transmission technology, inductively coupled wireless energy transmission technology and resonant wireless energy transmission technology.

Electromagnetic wave energy transmission technology uses the principle of antenna transmission and reception, such as using microwaves for wireless energy transmission. This technology can achieve extremely high transmission power. The main problem with this technology is that there must be no obstacles on the energy transmission path. That is, energy transmission cannot bypass or pass through obstacles.

The inductively coupled wireless energy transmission technology uses the principle of electromagnetic induction to realize non-contact power transmission by using loosely coupled transformers or separable transformers. The main problem with this technology is that the energy transmission distance is limited to the millimeter level due to the limitation of the transmission principle.

Resonant wireless power transmission technology is an energy transmission technology that makes the transmitting loop and receiving loop separated by a certain distance in a resonant state. It is suitable for wireless energy transmission at medium distances. Since the transmitting loop and the receiving loop are susceptible to various interferences in the actual working environment, it is difficult for the entire system to work in a resonant state, and the detuning of the system will cause a sharp drop in the transmission efficiency of the system.

Contents of the invention

The purpose of the present invention is to automatically adjust or control the resonant frequency of the system and make the whole system work in the resonant state in the wireless energy transmission device.

In order to achieve the purpose of the present invention, the first aspect of the present invention is to provide a method for controlling the resonant frequency of a wireless energy transmission device. Transmission of energy, characterized in that the resonance frequency control method includes detecting the output voltage and output current of the excitation power supply connected to the transmission loop; making the operating frequency of the excitation power supply and the natural frequency of the transmission loop respectively in the first frequency region and The second frequency region scans and changes, wherein both the first frequency region and the second frequency region include the third frequency region where the natural frequency of the receiving circuit is located, and the operating frequency of the excitation power supply and the natural frequency of the transmitting circuit respectively scan the first frequency region and the second frequency region at least once; record the magnitude and frequency of each output current of the excitation power detected when the output voltage and output current of the excitation power are in phase during the scanning process; select the minimum output among the recorded output currents The frequency of the current; then the operating frequency of the excitation power supply and the natural frequency of the transmitting loop are the same as the frequency of the minimum output current.

In the actual application system, the circuit parameters of the transmitting loop and the receiving loop will be affected by the environment, so that the natural frequency of the transmitting loop and the receiving loop will change. In fact, the natural frequency of the transmitting loop and the receiving loop The natural frequencies may vary within a certain frequency range. For example, the natural frequency of the receiving loop may vary within the third frequency range. Therefore, in the actual working environment, the detuning of the transmitting loop and the receiving loop is It's easy to happen.

The resonant frequency control method of the present invention only takes control measures at the transmitting end of the system, so that the operating frequency of the excitation power supply and the natural frequency of the transmitting loop are scanned and changed, and the natural frequency of the receiving loop is dynamically tracked, so that the entire system is in a resonant working state .

However, the existing technology usually needs to take control measures at both the transmitting end and the receiving end to make the whole system in a resonant working state; and in applications such as medical implant equipment, it is very difficult to take control measures at the receiving end of the system It is even impossible; therefore, the resonant frequency control method of the present invention can realize the resonant work of the system only by taking control measures at the transmitting end of the system, which is a major breakthrough in technology and has high application value .

Since the frequency of the output current of the excitation power supply is the same as the operating frequency of the excitation power supply, the frequency of the output current of the excitation power supply is also the operating frequency of the excitation power supply.

Scanning the first frequency region once refers to scanning from one end of the first frequency region to the other end of the first frequency region; similarly, scanning the second frequency region once refers to scanning from one end of the second frequency region to The other end of the second frequency region finishes scanning once in this way.

In the resonant frequency control method, the first frequency range may be greater than the second frequency range, the first frequency range may be equal to the second frequency range, or the first frequency range may be smaller than the second frequency range.

In a preferred embodiment, the first frequency region includes the second frequency region. In another preferred embodiment, the second frequency range includes the first frequency range.

In the resonant frequency control method, the natural frequency of the transmitting loop is scanned and changed in a certain step in the second frequency region, and the natural frequency of the transmitting loop is changed by a step per scan, and the excitation power supply If the working frequency is higher, the first frequency area is scanned once.

The change of one step per scan here refers to each increase or decrease of one step. If the step amount is 100 Hz, one step amount represents 100 Hz, and one step amount per sweep of the natural frequency means that the natural frequency increases or decreases by 100 Hz.

In the resonant frequency control method, the operating frequency of the excitation power source is scanned and changed in a certain step in the first frequency region, and the operating frequency of the excitation power source is changed by a step amount per scan, and the transmitting loop The natural frequency scans the second frequency region once.

In the resonant frequency control method, the natural frequency of the transmitting loop can be swept and changed by controlling the parameters of the resonant element of the transmitting loop. Preferably, the natural frequency of the transmitting loop is swept and varied by controlling the size of the resonant capacitance of the transmitting loop.

In the resonant frequency control method, the third frequency region where the natural frequency of the receiving circuit is located is usually pre-set, and the accuracy of the setting is verified through experiments. Usually, the third frequency region is required to be as small as possible, but it is required to receive The natural frequency of the loop can only vary within the third frequency region.

The second aspect of the present invention is to provide a new wireless energy transmission device, which uses electromagnetic field coupling to transmit energy from the transmitting loop at the transmitting end to the receiving loop at the receiving end, and is characterized in that the device includes a capacitor The matrix is used as the resonant element of the transmitting circuit; the detection circuit is used to detect the output voltage and output current of the excitation power connected to the transmitting circuit; the relay system is used to control the capacitance matrix so that the natural frequency of the transmitting circuit can be scanned and changed; oscillation The device is used to control the operating frequency of the excitation power supply; the single-chip microcomputer control unit is configured to control the oscillation frequency of the oscillator so that the operating frequency of the excitation power supply can be scanned and changed, and can control the relay system to make the natural frequency of the transmitting circuit Scanning changes can record the magnitude and frequency of each output current of the excitation power detected by the detection circuit when the output voltage of the excitation power is in phase with the output current, and can select the frequency of the minimum output current among the recorded output currents. The oscillator and the relay system can be controlled so that the operating frequency of the excitation power supply and the natural frequency of the transmitting loop are the same as the frequency of the minimum output current; wherein, the operating frequency of the exciting power supply and the natural frequency of the transmitting loop are respectively in the first frequency region and the second The scanning changes of the two frequency regions, the first frequency region and the second frequency region both include the third frequency region where the natural frequency of the receiving circuit is located.

The device of the present invention can make the operating frequency of the excitation power supply and the natural frequency of the transmitting circuit scan and change and dynamically track the natural frequency of the receiving circuit only by setting the control device at the transmitting end of the system, and realize the resonance work of the whole system. However, in the existing technology, it is usually necessary to install control devices at both the transmitting end of the system and the receiving end of the system, so as to make the whole system work in resonance. Thus, the device of the present invention represents a significant advance in the art.

In the device, the first frequency region may be greater than the second frequency region, the first frequency region may be equal to the second frequency region, or the first frequency region may be smaller than the second frequency region.

In a preferred embodiment, the first frequency region contains the second frequency region. In another preferred embodiment, the second frequency region contains the first frequency region.

Preferably, the natural frequency of the transmitting loop changes in a certain step in the second frequency region, and every time the natural frequency of the transmitting loop changes by a step, the operating frequency of the excitation power supply scans the first step. One frequency region once.

Preferably, the operating frequency of the excitation power supply is scanned and changed in a certain step in the first frequency region, and every time the operating frequency of the excitation power scans and changes by a step, the natural frequency of the transmitting circuit scans the first frequency. Two frequency areas again.

In the wireless energy transmission device, the natural frequency of the transmission loop can be swept and changed by changing the parameters of the capacitance matrix.

Description of drawings

Fig. 1 is a schematic structural diagram of a wireless energy transmission device of the present invention.

Fig. 2 is a schematic diagram of the relationship between the working frequency of the excitation power supply, the natural frequency of the transmitting loop and the natural frequency of the receiving loop in the wireless energy transmission device shown in Fig. 1 .

Fig. 3 is a schematic diagram of a control flow of a method for controlling a resonance frequency of a wireless energy transmission device.

Fig. 4 is a control flow of another embodiment of a method for controlling a resonance frequency of a wireless energy transmission device.

Detailed ways

Fig. 1 is a schematic structural diagram of a wireless energy transmission device of the present invention, which is composed of a transmitting end and a receiving end. In Figure 1, the transmitter consists of an excitation power supply , transmitting coil , emission capacitance and capacitance matrix The formed transmitting circuit and the control circuit mainly composed of a single-chip microcomputer control unit, a relay system and a detection circuit. Among them, the excitation power Includes DC power supply , by field effect tube and The half-bridge circuit, drive circuit and oscillator formed. The receiving end consists of a receiving coil , receiving capacitance and load formed receiving circuit.

In Figure 1, the detection circuit respectively detects the output voltage of the excitation power supply and output current , and then sent to the A/D converter for analog-to-digital conversion, and finally sent to the microprocessor MCU. The control signals sent by the microprocessor MCU respectively control the oscillator and the relay system to perform related operations through the I/O interface. Referring to Figure 2, the MCU control unit controls the oscillator and relay system so that the operating frequency of the excitation power Sweep changes in the first frequency region, so that the natural frequency of the transmitting loop Scan changes in the second frequency region, where the natural frequency of the receiving loop Within the third frequency region, both the first frequency region and the second frequency region include the third frequency region.

In Figure 1, the currents flowing through the transmitting loop and the receiving loop are respectively , , the transmitting coil with receiving coil The mutual inductance and distance between , , excitation power supply The internal resistance is , the transmitting coil with receiving coil The resistance of , , applying Kirchhoff's voltage law, the following formula can be obtained:

(1)

It can be solved by formula (1):

(2)

In the formula:

(3)

(4)

(5)

It can be seen from (2) that the output voltage of the excitation power supply and the current of the transmit loop When in phase, there is , then formula (2) can be changed to

(6)

It can be seen from (4) and (6) that the resistance The magnitude and angular frequency of closely related to the output voltage of the excitation power supply with the transmit loop In the case of the same phase, if the get the maximum value, then Get the minimum value.

make ,available When the maximum value is obtained, Should conform to the following formula:

(7)

in the formula is the quality factor of the receiving circuit, which conforms to the following formula:

(8)

Since in practical application systems, the quality factor Usually much greater than 1, then formula (7) can be changed to:

(9)

The above formula shows that the receiving circuit will be in a resonance state at this time. Substitute (9) into (5) and apply the relation , you can get:

(10)

The above formula shows that the transmitting circuit is also in a resonance state at this time.

Therefore, at high value in the application system, the output voltage of the excitation power supply and the current of the transmit loop In the case of the same phase, When the minimum value is obtained, the transmitting circuit and the receiving circuit are basically in a state of resonance. This is the theoretical basis that the resonance frequency control technology of the present invention is only controlled at the transmitting end.

Figure 2 shows the operating frequency of the excitation power supply of this embodiment , The natural frequency of the transmitting circuit and the natural frequency of the receiving loop The relationship between the three. It can be clearly seen in Figure 2 that the operating frequency of the excitation power supply The scan range is to Between, the natural frequency of the transmitting loop The scan range is to Between, the natural frequency of the receiving loop available at to change between, among them, The scan range includes The entire frequency band that may vary, The scan range includes scan range.

In this embodiment, the natural frequency of the transmitting loop In the second frequency area, the step is 100 Hz, and the natural frequency of the transmitting circuit changes by 100 Hz, the operating frequency of the excitation power supply Just scan the first frequency area once. If the natural frequency of the transmitting loop from frequency scan to frequency Need to step N times, that is, change N 100 Hz, then the operating frequency of the excitation power supply Just scan the first frequency region N times, so that when the natural frequency of the transmitting loop from frequency scan to frequency , the operating frequency of the excitation power supply After scanning the first frequency region N times, the output voltage and output current of the excitation power supply are in the same phase state for N times. The size and frequency of the N output currents of the power supply, and select the frequency of the smallest output current among the recorded N output currents, and then control the oscillator and relay system to make the operating frequency of the excitation power supply and the natural frequency of the transmitting loop are the same frequency as this minimum output current, so that the whole system will be in resonance.

Fig. 3 is a schematic diagram of the control flow of the method for controlling the resonant frequency of the wireless energy transmission device of the present invention. As can be seen in Figure 3, the resonance frequency control method includes: detecting the output voltage of the excitation power supply connected to the transmission loop and output current ; Make the operating frequency of the excitation power supply and the natural frequency of the transmitting loop Sweep changes in the first frequency region and the second frequency region respectively, and make the operating frequency of the excitation power supply and the natural frequency of the transmitting loop Scanning the first frequency region and the second frequency region at least once respectively, wherein both the first frequency region and the second frequency region include the natural frequency of the receiving loop The third frequency region in which it is located; record the output voltage of the excitation power supply during the sweep and output current The magnitude and frequency of each output current of the excitation power detected when it is in the same phase; select the frequency of the smallest output current among the recorded output currents ; Then make the operating frequency of the excitation power supply and the natural frequency of the transmitting loop are related to the frequency of the minimum output current same.

Fig. 4 shows the control flow of another embodiment of the method for controlling the resonant frequency of the wireless energy transmission device. In this embodiment, the resonance frequency control method includes: system initialization, which is the parameter , , , assigned separately , , 0, 0, where , are respectively the lowest frequency of the first frequency region and the second frequency region; control the oscillator so that the operating frequency of the excitation power Work at the lowest frequency in the first frequency region , to control the capacitance matrix of the transmitting loop to make the natural frequency of the transmitting loop Work at the lowest frequency in the second frequency region ;Detect the excitation power connected to the transmission loop output voltage and output current ; for parameters Whether it is greater than 0 is judged, and the output voltage and output current Whether it is in phase is judged; when the natural frequency of the transmitting circuit works at the lowest frequency of the second frequency region, the operating frequency of the excitation power supply in steps from the lowest frequency in the first frequency region Scan to the highest frequency in the first frequency zone ,Natural frequency Each increment , the operating frequency of the excitation power supply in steps Scan the first frequency area once, when the natural frequency of the transmitting circuit scans to the highest frequency of the second frequency area And the operating frequency of the excitation power supply is also swept to the highest frequency in the first frequency region After that, its scanning is temporarily stopped, and the output voltage during the above scanning process is recorded and output current The magnitude and frequency of the individual output currents when in phase; select the smallest of the recorded output currents Frequency of ; Then make the operating frequency of the excitation power supply and the natural frequency of the transmitting circuit consistent with the minimum current Frequency of same, and for the parameter Increment by 1 for subsequent control. In this embodiment, the resonant frequency control method also includes clearing the magnitude and frequency of each recorded output current to save storage space; the ratio of the offset of the output current detected during operation to the original output current Is it greater than To make a judgment, the parameters here Can be set as needed, for example can be set to , if the judging condition is not established, the system will work at the frequency of the originally selected minimum current, if the judging condition is true, a new minimum current frequency will be reselected according to the process described above, and the operating frequency of the excitation power supply and the transmitting circuit will be The natural frequency of is the same as the frequency of the new minimum current.

While there has been shown and described what are presently considered to be the preferred embodiments of the invention, it will be apparent that various changes and modifications will be apparent to those skilled in the art. These changes or improvements all belong to the scope of the present invention defined by the appended claims.

Claims (2)

1. A wireless energy transmission device, the device utilizes the coupling of an electromagnetic field to transmit energy from a transmitting loop at a transmitting end to a receiving loop at a receiving end, wherein the device includes: a capacitance matrix as a resonant element of the transmitting loop; The detection circuit is used to detect the output voltage and output current of the excitation power connected to the transmission loop; the relay system is used to control the capacitance matrix so that the natural frequency of the transmission loop can be scanned and changed; the oscillator is used to control the operation of the excitation power supply Frequency; the single-chip microcomputer control unit, the single-chip microcomputer control unit is set to, can control the oscillation frequency of the oscillator to make the operating frequency scanning change of the excitation power supply, can control the relay system to make the natural frequency scanning change of the transmitting circuit, and can be recorded in the excitation power supply When the output voltage and output current are in the same phase, the detection circuit detects the magnitude and frequency of each output current of the excitation power supply, can select the frequency of the minimum output current among the recorded output currents, and can also control the oscillator and relay system to make the excitation The operating frequency of the power supply and the natural frequency of the transmitting loop are the same as the frequency of the minimum output current; wherein, the operating frequency of the exciting power supply and the natural frequency of the transmitting loop scan and change in the first frequency region and the second frequency region respectively, and the first frequency Both the region and the second frequency region include a third frequency region where the natural frequency of the receiving circuit is located, the operating frequency of the exciting power supply is scanned and changed in a certain step in the first frequency region, and the operating frequency of the exciting power supply Every time the scanning changes by one step, the natural frequency of the transmitting loop scans the second frequency region once. 2. The device according to claim 1, characterized in that, the natural frequency of the transmitting loop is swept and changed by changing the parameters of the capacitance matrix.