WPT system based on four-pole-plate coupling full-duplex communication and parameter design method

Abstract

The invention provides a WPT system and a parameter design method based on four-pole-plate coupling full-duplex communication, four groups of coupling pole plates are arranged in the system, the first group of coupling pole plates and the second group of coupling pole plates are used as coupling structures of energy transmission channels, the first group of coupling pole plates and the third group of coupling pole plates are used as data forward transmission coupling interfaces, and the third group of coupling pole plates are used as data reverse transmission coupling interfaces. The second group of coupling polar plates and the fourth group of coupling polar plates are used as data reverse transmission coupling interfaces, a primary side signal source and a primary side LC wave blocking network are arranged between two primary side polar plates of the data forward transmission coupling interface, and a secondary side compensation inductor and a secondary side sampling resistor are arranged between two secondary side polar plates of the data forward transmission coupling interface; a primary side compensation inductor and a primary side sampling resistor are arranged between two primary side pole plates of the data reverse transmission coupling interface, and a secondary side signal source and a secondary side LC wave blocking network are arranged between two secondary side pole plates of the data reverse transmission coupling interface. The invention has the effect that the full duplex mode transmission of signals can be realized by using fewer devices.

Description

Technical Field

[0001] The present invention relates to the field of wireless power transmission, and in particular to a WPT system based on quadrupole plate coupling full-duplex communication and a parameter design method. Background Art

[0002] In recent years, in the field of wireless power transmission (WPT), wireless power transmission technology based on electric field coupling technology (EC-WPT) has attracted the attention of many researchers at home and abroad due to its unique advantages. Electric field coupling electric power transmission technology comprehensively utilizes modern power electronic energy conversion technology, electric field coupling technology, high-power high-frequency conversion technology, and uses modern control theory and methods to achieve wireless transmission of electric energy. This technology provides a new way for wireless power transmission, promotes the development and application of wireless power transmission technology, and has high practical value.

[0003] In some practical applications, the system often needs to detect the operating status of the equipment or transmit control instructions on the basis of satisfying energy transmission, which requires the system to have the ability to wirelessly transmit energy signals in parallel. The power transmission channel provides power and energy for the system operation, and the signal transmission channel is used to transmit data such as status information.

[0004] From the perspective of several proposed methods of parallel transmission of electric energy and signals in EC-WPT systems, it is difficult to achieve bidirectional signal transmission by using energy modulation; using shared channels, the signal transmission rate is relatively high at low power, but when the power is high, the interference of electric energy transmission on signal transmission is large, and additional isolation circuits and control algorithms need to be added to solve the crosstalk problem, which increases the circuit complexity and design difficulty; using partial energy channels, it is easy to achieve high-speed signal transmission, and the mutual crosstalk between energy transmission and signal transmission is relatively small, but in large and high-power systems, electric energy crosstalk will still greatly affect the reliable transmission of signals, and will also affect the efficiency of energy transmission. It is necessary to solve the isolation problem of data transmission and energy transmission to solve the crosstalk between the two. It is not easy to achieve bidirectional signal transmission by using other modules to achieve communication. Time-division multiplexing is often used to achieve full-duplex data communication, which increases the complexity of operation and requires the introduction of other switching devices. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a WPT system based on quadrupole plate coupling full-duplex communication, which can realize full-duplex transmission of signals with the help of four inductors, two capacitors, two signal sources and two sampling resistors, and does not require an additional data coupling transformer, and the volume is greatly reduced. With the help of two pairs of coupling plate capacitors of the energy channel, a partial energy channel is adopted, two pairs of signal coupling plate capacitors are added, and a double-sided LC filtering structure is adopted to isolate the interference of the energy channel to the signal channel, improve the quality of system signal transmission and the signal-to-noise ratio of signal transmission without affecting the transmission of energy.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A WPT system based on quadrupole plate coupling full-duplex communication comprises an energy transmission channel and a data transmission channel, and the key lies in that: four groups of coupling plates are arranged in the system, wherein: a first group of coupling plates and a second group of coupling plates are used as coupling structures of the energy transmission channel, the first group of coupling plates and a third group of coupling plates are used as data forward transmission coupling interfaces, the second group of coupling plates and a fourth group of coupling plates are used as data reverse transmission coupling interfaces, a primary signal source and a primary LC wave blocking network are arranged between two primary plates of the data forward transmission coupling interface, a secondary compensation inductor and a secondary sampling resistor are arranged between two secondary plates of the data forward transmission coupling interface; a primary compensation inductor and a primary sampling resistor are arranged between two primary plates of the data reverse transmission coupling interface, and a secondary signal source and a secondary LC wave blocking network are arranged between two secondary plates of the data reverse transmission coupling interface.

[0008] Optionally, the energy transmission channel also includes a direct current power supply, a high-frequency inverter, a primary compensation network, a secondary compensation network, a rectifier filter and an electrical load.

[0009] Optionally, both the primary compensation network and the secondary compensation network adopt an LC series resonant network, wherein: the primary plates in the first group of coupling plates and the second group of coupling plates are respectively connected to the two ends of the compensation capacitor in the primary compensation network, and the secondary plates in the first group of coupling plates and the second group of coupling plates are respectively connected to the two ends of the compensation capacitor in the secondary compensation network.

[0010] Optionally, the operating frequency of energy transmission is 392 kHz, the carrier frequency of the primary signal source is 25 MHz, and the carrier frequency of the secondary signal source is 20 MHz.

[0011] Optionally, the operating angular frequency of energy transmission is w p , the carrier frequency of the primary signal source is w 1 , the carrier frequency w of the secondary signal source 2 , then the secondary side LC wave blocking network satisfies:

[0012]

[0013] L s2 is the primary compensation inductance, L r2 is the inductance value of the secondary LC wave-blocking network, C r2 is the capacitance value of the secondary LC wave-blocking network, C eq2 It is the equivalent capacitance value of the second group of coupling plates and the fourth group of coupling plates in series in the data reverse transmission coupling interface.

[0014] Optionally, the primary LC wave-blocking network satisfies:

[0015]

[0016] L s1 is the secondary compensation inductance, L r1 is the inductance value of the primary LC wave-blocking network, C r1 is the capacitance value of the primary LC wave-blocking network, C eq1 The equivalent capacitance value of the first group of coupling plates and the third group of coupling plates in series in the data forward transmission coupling interface.

[0017] Based on the above system, the present invention also provides a parameter design method, comprising the following steps:

[0018] S1: According to the application scenario, determine the working angular frequency of energy transmission as w p , the carrier frequency of the primary signal source is w 1 , the carrier frequency w of the secondary signal source 2 ;

[0019] S2: Determine the installation positions and sizes of the four sets of coupling plates according to the structural space of the application scenario, and obtain the corresponding equivalent capacitance values;

[0020] S3: Configure the primary compensation inductor L s2 and the secondary compensation inductance L s1 , determine the component parameters in the primary side LC choke network and the secondary side LC choke network according to the choke requirements.

[0021] Optionally, in step S3:

[0022] and

[0023] Configure the capacitance value C in the primary LC wave blocking network r1 and the inductance value L in the primary LC wave-blocking network r1 , C eq1 The equivalent capacitance value of the first group of coupling plates and the third group of coupling plates in series in the data forward transmission coupling interface;

[0024] At the same time, follow: and

[0025] Configure the capacitance value C in the secondary side LC wave blocking network r2 and the inductance value L in the secondary LC wave-blocking network r2 , C eq2 It is the equivalent capacitance value of the second group of coupling plates and the fourth group of coupling plates in series in the data reverse transmission coupling interface.

[0026] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0027] The present invention provides a WPT system based on quadrupole plate coupling full-duplex communication, which shares the energy channel coupling plate capacitance in the data transmission channel, and can use fewer devices to realize the full-duplex mode transmission of signals. The bilateral LC filter structure is used to effectively isolate the interference of the energy channel, and at the same time, the coupling data transformer is not used, which can effectively reduce the volume of the circuit. Through parameter configuration, the system can be in a resonant state at the data carrier frequency, which can improve the data transmission voltage gain, and at the same time, it is in a state of infinite impedance at the energy carrier frequency, which can effectively isolate the interference of the energy channel and improve the signal-to-noise ratio and transmission rate of data transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings of the present invention are as follows.

[0029] Figure 1 The WPT system topology structure based on quadrupole plate coupling full-duplex communication provided by the present invention;

[0030] Figure 2 The data reverse transmission circuit structure and impedance characteristics in a specific embodiment of the present invention;

[0031] Figure 3 The data forward transmission circuit structure and impedance characteristics in a specific embodiment of the present invention;

[0032] Figure 4 It is the equivalent circuit of the data forward transmission channel;

[0033] Figure 5 Schematic diagram for analyzing the interference of reverse data transmission on forward data transmission;

[0034] Figure 6 It is a schematic diagram of a signal demodulation circuit in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0036] like Figure 1As shown, this embodiment provides a WPT system based on quadrupole plate coupling full-duplex communication, including an energy transmission channel and a data transmission channel, and four groups of coupling plates are arranged in the system, wherein: the first group of coupling plates and the second group of coupling plates are used as coupling structures of the energy transmission channel, the first group of coupling plates and the third group of coupling plates are used as data forward transmission coupling interfaces, the second group of coupling plates and the fourth group of coupling plates are used as data reverse transmission coupling interfaces, a primary signal source and a primary LC wave blocking network are arranged between the two primary plates of the data forward transmission coupling interface, and a secondary compensation inductor and a secondary sampling resistor are arranged between the two secondary plates of the data forward transmission coupling interface; a primary compensation inductor and a primary sampling resistor are arranged between the two primary plates of the data reverse transmission coupling interface, and a secondary signal source and a secondary LC wave blocking network are arranged between the two secondary plates of the data reverse transmission coupling interface.

[0037] pass Figure 1 It can be seen that the energy transmitting end and the energy receiving end are respectively equipped with 4 coupling plates, and unidirectional energy transmission and full-duplex data communication can be realized through four sets of coupling plates. In specific implementation, the energy transmission channel consists of a DC power supply Edc, a full-bridge inverter composed of four MOSFETs (S1-S4), an LC compensation topology, a coupling plate, a rectifier and a load. After passing through the LC resonant network, it is loaded on the coupling plate, and a high-frequency alternating electric field is generated between the coupling plates to form a displacement current, which transmits the electric energy from the transmitting side to the receiving side. The electric energy receiving side then passes through the LC resonant network, and after rectification and filtering, it realizes power supply to the load. The data transmission channel consists of a signal source, a transmitting circuit and a receiving circuit. The data transmission channel has a bidirectional transmission direction. The signal is mainly transmitted through the loop composed of Cs2 and Cs1 and the data transmission circuit, which is separated from the power transmission loop.

[0038] Combination Figure 1It can be seen that the ECPT system with double-sided LC compensation is adopted in this embodiment. The ECPT system with this compensation method has a simple structure and good constant voltage characteristics. The Lfp and Cfp resonant networks on the power transmitting side compensate the capacitive reactance of the coupling capacitor to a certain extent and increase the plate excitation voltage; the Lfs and Cfs resonant networks on the receiving side are intended to achieve impedance matching to improve the system output capacity. Uin and Iin are the output voltage and output current after inversion, respectively. At the same time, Uo and Io are the voltage and current on the load, respectively. RL is the equivalent load resistance when the system is charging. Cd is the secondary DC filter capacitor. The four power electronic switches S1-S4 form a primary-side full-bridge inverter. The four diodes D1-D4 form a secondary-side full-bridge rectifier. In a specific implementation, the primary plates in a group of coupling plates and the second group of coupling plates are respectively connected to the two ends of the compensation capacitor in the primary compensation network, and the secondary plates in the first group of coupling plates and the second group of coupling plates are respectively connected to the two ends of the compensation capacitor in the secondary compensation network, so that the resonant compensation capacitor and the coupling plate equivalent capacitance in the energy transmission channel act between the signal forward transmission channel and the signal reverse transmission channel at the same time, which not only realizes the shared utilization of components, but also enhances the isolation effect between data transmission channels.

[0039] Specifically, the reverse transmission channel of data in this example is simplified to Figure 2 As shown, its circuit structure is as follows Figure 2 As shown in part (a), the impedance characteristics are as follows Figure 2 As shown in part (b), when designing the parameters of the reverse data transmission channel, the parameter L is fixed in advance. s2 , C s2 , C s4 , assuming that the blocking frequency is the energy transmission channel frequency f p , through frequency f 2 , and at the same time satisfy f 2 Much larger than f p .

[0040] Combined with the circuit topology, the coupling plate capacitor C s2 and C S4 Can be equivalent to capacitance C eq2 :

[0041]

[0042] The impedance of the reverse data transmission branch can be expressed as Z d2 (w):

[0043]

[0044] The reverse data transmission branch is at frequency f 2 The impedance is zero at frequency f pThe impedance is infinite. The blocking frequency of the parallel LC blocking network is f p , then L r2 With C r2 Relationship satisfaction:

[0045]

[0046] The impedance of the reverse data transmission branch at frequency f2 is Z d2 (w 2 ) is zero, then:

[0047]

[0048] From equation (3) and equation (4), we can get C r2 for:

[0049]

[0050] From equation (3) and equation (5), we can get L r2 for:

[0051]

[0052] Similarly, the data forward transmission channel circuit and impedance characteristics are as follows Figure 3 As shown, when designing the parameters of the data forward transmission channel, the parameter L is fixed in advance. s1 , C s1 , C s3 Assume that the blocking frequency is the energy transmission channel frequency f p , through frequency f 1 , and at the same time satisfy f 1 Much larger than f p .

[0053] Coupling plate capacitance C s1 and C S3 Can be equivalent to capacitance C eq1 :

[0054]

[0055] The impedance of the forward data transmission branch can be expressed as Z d1 (w):

[0056]

[0057] The forward data transmission branch is at frequency f 1 The impedance is zero at frequency f p The impedance at the point is infinite, and the blocking frequency of the parallel LC blocking network is f p , then L r1 With C r1 Relationship satisfaction:

[0058]

[0059] The forward data transmission branch is at frequency f 1 Impedance Z d1 (w 1 ) is zero, then:

[0060]

[0061] From equations (9) and (10), we can get C r1 for:

[0062]

[0063] From equations (9) and (11), we can get L r1 for:

[0064]

[0065] When only the data transmission channel is analyzed, the power supply Uin in the energy transmission channel can be regarded as a short circuit, and the equivalent circuit is as follows: Figure 4 As shown, at the data carrier frequency w 1 and w 2 Taking forward data transmission as an example, the voltage gain of forward data transmission can be derived. The modulation signal is from the data carrier source U sig1 Injection and receiving resistor R 1 Extract from:

[0066] Forward data transmission channel data voltage gain G df for:

[0067]

[0068] In view of the interference of reverse data on forward data transmission, the corresponding impedance analysis is as follows: Figure 5 As shown, Z bf1 , Z bf2 , Z bf3 They are the data signal source U sig2 The equivalent input impedance of each port when viewed from left to right. The equivalent impedance of each part is expressed in the time domain as:

[0069]

[0070] The interference voltage gain of each part caused by the interference of reverse data transmission on forward data transmission is:

[0071]

[0072] Based on formula (15), the interference gain G of reverse data transmission on forward data transmission isbf It can be expressed as:

[0073]

[0074] Therefore, the signal-to-noise ratio of the forward transmission of the present invention is calculated based on the gain derived from equations (13) and (16):

[0075]

[0076] Signal demodulation refers to the process of restoring the carrier at the receiving end to a digital signal. Envelope demodulation is the simplest demodulation method of ASK modulation, which restores the digital signal by obtaining the carrier envelope. Figure 6 This is the signal receiving and demodulation schematic diagram. The input is the pickup voltage across the detection resistors R1 and R2. The system noise is filtered out through a bandpass filter built by an operational amplifier device, and then passes through a detection diode and a low-pass filter network. Finally, it is shaped by a voltage hysteresis comparator to restore the digital signal.

[0077] Based on the above analysis, in specific implementation, the WPT system parameter design based on quadrupole plate coupled full-duplex communication of the system proposed in the present invention can be carried out according to the following steps:

[0078] S1: According to the application scenario, determine the working angular frequency of energy transmission as w p , the carrier frequency of the primary signal source is w 1 , the carrier frequency w of the secondary signal source 2 ;

[0079] S2: Determine the installation positions and sizes of the four sets of coupling plates according to the structural space of the application scenario, and obtain the corresponding equivalent capacitance values;

[0080] S3: Configure the primary compensation inductor L s2 and the secondary compensation inductance L s1 , determine the component parameters in the primary side LC choke network and the secondary side LC choke network according to the choke requirements.

[0081] Wherein: In step S3, according to:

[0082]

[0083] Configure the capacitance value C in the primary LC wave blocking network r1 and the inductance value L in the primary LC wave-blocking network r1 , C eq1 The equivalent capacitance value of the first group of coupling plates and the third group of coupling plates in series in the data forward transmission coupling interface;

[0084] At the same time, follow: and

[0085] Configure the capacitance value C in the secondary side LC wave blocking network r2 and the inductance value L in the secondary LC wave-blocking network r2 , C eq2 It is the equivalent capacitance value of the second group of coupling plates and the fourth group of coupling plates in series in the data reverse transmission coupling interface.

[0086] Based on the above system and parameter design, this embodiment uses simulation software to build a system for verification, in which: the operating frequency of the energy transmission channel is 392kHz, the DC input voltage is 200V, and the output power is 1.95kw. The carrier frequency of the forward data signal source is 25MHz, the signal amplitude is 12V, the carrier frequency of the reverse data signal source is 20MHz, the signal amplitude is 12V, and the output voltage Uo on the equivalent AC load resistance is 198V. The simulation results without adding the signal loop show that the output voltage Uo is 198V and the electric energy transmission power is 1.95kw. The simulation results with the addition of the signal loop show that the output voltage Uo is 198V and the electric energy transmission power is 1.95kw. There is almost no change in the transmission power before and after the addition, which shows that the signal channel has no effect on the system transmission power.

[0087] At the same time, the forward and reverse modulation carrier peaks are 12V, and the signal detection resistor carrier peak is 12V. It can be seen that the signal voltage attenuation is close to zero, which verifies the correctness of the signal attenuation model and explains that the signal branch is in a resonant state at the corresponding carrier frequency, ensuring the high voltage gain of data transmission. Taking forward data transmission as an example, in the signal branch without a signal source, the peak value of the electric energy crosstalk on the detection resistor R1 after power-on is 0.12V. It can be seen that the crosstalk is 1%. According to formula (17), the theoretical value is 0.98%. From the simulation results, it can be seen that the parameter design of the signal branch can effectively filter out the interference of the energy channel. The interference voltage mainly comes from the high-order harmonic interference of the inverter. At the same time, the signal carrier waveform on the sampling resistor is basically not distorted, and the data transmission has a high signal-to-noise ratio.

[0088] Under the premise of ensuring the power transmission of electric energy, the channel is used to achieve stable and reliable parallel transmission of signals. At the same time, the complexity of the channel and the overall system cost are reduced. In addition, the effectiveness of this method is verified through simulation and experiments, and the simulation system built achieves parallel transmission of signals in both directions at 1Mbit / s.

[0089] From the above, it can be seen that the WPT system based on quadrupole plate coupling full-duplex communication and its parameter design method proposed by the present invention share the energy channel coupling plate capacitance in the data transmission channel, and can use fewer devices to realize the full-duplex mode transmission of signals. The bilateral LC filtering structure is used to effectively isolate the interference of the energy channel, and at the same time, the coupling data transformer is not used, which can effectively reduce the volume of the circuit. Through parameter configuration, the system can be in a resonant state at the data carrier frequency, which can improve the data transmission voltage gain, and at the same time, it is in a state of infinite impedance at the energy carrier frequency, which can effectively isolate the interference of the energy channel and improve the signal-to-noise ratio and transmission rate of data transmission.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A WPT system based on quadrupole plate coupling full-duplex communication, including an energy transmission channel and a data transmission channel, characterized in that: Four groups of coupling plates are arranged in the system, wherein: the first group of coupling plates and the second group of coupling plates are used as coupling structures of energy transmission channels, the first group of coupling plates and the third group of coupling plates are used as data forward transmission coupling interfaces, the second group of coupling plates and the fourth group of coupling plates are used as data reverse transmission coupling interfaces, a primary signal source and a primary LC wave-blocking network are arranged between the two primary plates of the data forward transmission coupling interface, a secondary compensation inductor and a secondary sampling resistor are arranged between the two secondary plates of the data forward transmission coupling interface; a primary compensation inductor and a primary sampling resistor are arranged between the two primary plates of the data reverse transmission coupling interface, and a secondary signal source and a secondary LC wave-blocking network are arranged between the two secondary plates of the data reverse transmission coupling interface.

2. The WPT system based on quadrupole plate coupling full-duplex communication according to claim 1, characterized in that: The energy transmission channel also includes a direct current power supply, a high-frequency inverter, a primary compensation network, a secondary compensation network, a rectifier filter and an electrical load.

3. The WPT system based on quadrupole plate coupling full-duplex communication according to claim 2, characterized in that: The primary compensation network and the secondary compensation network both adopt LC series resonant networks, wherein: the primary plates in the first group of coupling plates and the second group of coupling plates are respectively connected to the two ends of the compensation capacitor in the primary compensation network, and the secondary plates in the first group of coupling plates and the second group of coupling plates are respectively connected to the two ends of the compensation capacitor in the secondary compensation network.

4. The WPT system based on quadrupole plate coupling full-duplex communication according to claim 1, 2 or 3, characterized in that: The operating frequency of energy transmission is 392kHZ, the carrier frequency of the primary signal source is 25MHz, and the carrier frequency of the secondary signal source is 20MHz.

5. The WPT system based on quadrupole plate coupling full-duplex communication according to claim 3, characterized in that: The operating angular frequency of energy transmission is w p , the carrier frequency of the primary signal source is w1, and the carrier frequency of the secondary signal source is w2, then the secondary LC wave-blocking network satisfies: and L s2 is the primary compensation inductance, L r2 is the inductance value of the secondary LC wave-blocking network, C r2 is the capacitance value of the secondary LC wave-blocking network, C eq2 It is the equivalent capacitance value of the second group of coupling plates and the fourth group of coupling plates in series in the data reverse transmission coupling interface.

6. The WPT system based on quadrupole plate coupling full-duplex communication according to claim 5, characterized in that: The primary side LC wave blocking network meets the following requirements: and L s1 is the secondary compensation inductance, L r1 is the inductance value of the primary LC wave-blocking network, C r1 is the capacitance value of the primary LC wave-blocking network, C eq1 The equivalent capacitance value of the first group of coupling plates and the third group of coupling plates in series in the data forward transmission coupling interface.

7. A parameter design method for a WPT system based on quadrupole plate coupling full-duplex communication as described in any one of claims 1 to 6, characterized in that: The following steps are involved: S1: According to the application scenario, determine the working angular frequency of energy transmission as w p , the carrier frequency of the primary signal source is w1, and the carrier frequency of the secondary signal source is w2; S2: Determine the installation positions and sizes of the four sets of coupling plates according to the structural space of the application scenario, and obtain the corresponding equivalent capacitance values; S3: Configure the primary compensation inductor L s2 and the secondary compensation inductance L s1 , determine the component parameters in the primary side LC choke network and the secondary side LC choke network according to the choke requirements.

8. The parameter design method of the WPT system based on quadrupole plate coupling full-duplex communication as claimed in claim 7, characterized in that: In step S3, follow: and Configure the capacitance value C in the primary LC wave blocking network r1 and the inductance value L in the primary LC wave-blocking network r1 , C eq1 The equivalent capacitance value of the first group of coupling plates and the third group of coupling plates in series in the data forward transmission coupling interface; At the same time, follow: and Configure the capacitance value C in the secondary side LC wave blocking network r2 and the inductance value L in the secondary LC wave-blocking network r2 , C eq2 It is the equivalent capacitance value of the second group of coupling plates and the fourth group of coupling plates in series in the data reverse transmission coupling interface.

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