CN211296328U

CN211296328U - Electric field coupling wireless power transmission system of series autonomous fractional order circuit

Info

Publication number: CN211296328U
Application number: CN201922289431.5U
Authority: CN
Inventors: 张波; 疏许健; 江彦伟; 魏芝浩
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2019-12-17
Filing date: 2019-12-17
Publication date: 2020-08-18
Anticipated expiration: 2029-12-17

Abstract

The utility model discloses a series autonomous fractional order circuit electric field coupling wireless power transmission system, including fractional order transmitting circuit, fractional order series receiving circuit and coupling capacitance metal polar plate, fractional order transmitting circuit and fractional order series receiving circuit are connected through two coupling capacitance metal polar plates that are connected in parallel; the fractional order transmitting circuit comprises a primary side fractional order inductor with the order more than 1 and a primary side fractional order capacitor with the order less than or equal to 1 which are connected in series; the fractional order series type receiving circuit includes a secondary side fractional order inductance having an order of 1 or less, a secondary side fractional order capacitance having an order of 1 or less, and a load connected in series. The utility model discloses simple structure is reliable, need not high frequency voltage source, and system efficiency and transmission power can adapt to electric field coupling coefficient and resonant frequency's change automatically, are favorable to more high-power, more distant wireless power transmission, are particularly useful for the application scenario of high-power load.

Description

Electric field coupling wireless power transmission system of series autonomous fractional order circuit

Technical Field

The utility model belongs to the technical field of space electric field coupling wireless power transmission's technique and specifically relates to indicate a tandem type is from the transmission system of fractional order circuit electric field coupling wireless power.

Background

According to different power transmission implementation mechanisms and modes, wireless power transmission technologies can be broadly classified into inductive coupling type wireless power transmission technologies, magnetic resonance coupling type wireless power transmission technologies, microwave type wireless power transmission technologies, and electric field coupling type wireless power transmission technologies. Among them, the inductive coupling type, the magnetic resonance coupling type, and the electric field coupling type wireless power transmission technology are most widely studied.

As one of the most widely studied wireless power transmission technologies, the electric field coupling wireless power transmission technology can achieve the same level of transmission distance, output power and transmission efficiency as compared with the inductive coupling wireless power transmission technology, but the energy transmission form is an interactive electric field, the transmission of energy is to transmit energy by using a metal barrier as a part of a coupling plate without being blocked by the metal barrier, and the electric field is basically limited to exist between the coupling plates, so that the electromagnetic interference is greatly reduced. Compared with the magnetic resonance coupling wireless power transmission technology, the electric field coupling mechanism is simple, light and thin, low in cost and easy to change in shape, most of electric flux of the electric field coupling mechanism is distributed between the coupling polar plates in the working state, electromagnetic interference on the surrounding environment is small, and in addition, when metal barriers exist between or around the electric field coupling mechanism, eddy current loss is not generated on the conductor.

At present, the traditional space electric field coupling wireless power transmission system can be divided into a series-series type, a series-parallel type, a parallel-series type and a parallel-parallel type according to different connection modes of an inductor and a capacitor, wherein the receiving circuit adopts the series connection and is suitable for the application occasions of high-power loads, such as electric automobiles and the like, while the receiving circuit adopts the parallel connection and is suitable for the application occasions of low-power loads, such as consumer electronics products, such as mobile phones and the like, and different connection modes have great research significance and practical application value.

The transmission efficiency of a traditional receiving circuit series type space electric field coupling wireless electric energy transmission system is greatly influenced by the transmission distance, the transmission efficiency is greatly reduced along with the increase of the distance, the effective electric energy transmission interval of the system is very short, and the practical application of the system is not facilitated. Moreover, under the influence of ambient temperature, load, surrounding metal objects or electromagnetic environment, etc., the resonant frequency of the resonator in the electric field coupling wireless power transmission system is easily shifted, and the slight shift of the resonant frequency can cause the electric energy to be unable to be completely transmitted, so the conventional method cannot adapt to the situation that the resonant frequency and the transmission distance are shifted due to the interference of the system by external environment or internal factors, and the transmission efficiency and the output power cannot be kept stable.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome prior art's shortcoming and not enough, a tandem type is from the digital circuit electric field coupling wireless power transmission system is proposed, utilize the primary side fractional order inductance that the order is greater than 1 and the fractional order electric capacity and the fractional order tandem type receiving circuit that the order is less than or equal to 1 to constitute autonomous system, make the primary side fractional order inductance that the order is greater than 1 not only provide the energy for the circuit, its operating frequency and inductance value can follow system parameter change automatically when the order is fixed simultaneously, do not need any other regulation, with the pair of constancy that realizes system transmission efficiency and output, traditional electric field coupling wireless power transmission system has been solved when slight skew and electric field coupling coefficient change take place at resonant frequency, the efficiency that causes drops rapidly or the unstable inherent bottleneck problem of output. And the smaller the load resistance is, the longer the constant running distance of the output power and the transmission efficiency is, the more high-power and longer-distance realization is facilitated, and the application prospect of the wireless electric energy transmission in the high-power field of the electric automobile and the like is greatly widened.

In order to achieve the above object, the present invention provides a technical solution: a series connection type autonomous fractional order circuit electric field coupling wireless electric energy transmission system comprises a fractional order transmitting circuit, a fractional order series connection type receiving circuit and coupling capacitor metal plates, wherein the fractional order transmitting circuit and the fractional order series connection type receiving circuit are connected through the two coupling capacitor metal plates which are connected in parallel, and further wireless electric energy transmission is achieved in an electric field coupling mode; the fractional order transmitting circuit comprises a primary side fractional order inductor and a primary side fractional order capacitor, wherein the primary side fractional order inductor is connected in series, the order of the primary side fractional order inductor is greater than 1, the primary side fractional order capacitor is smaller than or equal to 1, the primary side fractional order inductor has the property of negative resistance and provides energy for the circuit, and the working frequency and the inductance value of the primary side fractional order inductor can automatically follow the change of system parameters when the order is fixed, so that the transmission efficiency and the output power of the system have strong robustness to the change of the system parameters and are constant; the apparent power of the primary fractional order inductor is constant and has two operating modes: the fractional order inductor has a constant order, the working frequency and the inductance value automatically follow the change of system parameters to keep the fractional order inductor to work stably, and the working frequency is fixed, and the order and the inductance value automatically follow the change of the system parameters to keep the fractional order inductor to work stably; the fractional order series type receiving circuit comprises a secondary side fractional order inductor with the order less than or equal to 1, a secondary side fractional order capacitor with the order less than or equal to 1 and a load which are connected in series, the current gain of the fractional order series type receiving circuit is constant, the coupling interval with the output power and the transmission efficiency constant depends on the load resistance, the smaller the load resistance is, the longer the critical coupling distance is, and the realization of the long-distance wireless power supply of a load with higher power is facilitated.

Further, the differential relation between the voltage and the current of the primary side fractional order inductor and the secondary side fractional order inductor satisfies the following condition:

the phase relation satisfies:

wherein i_LIs the current of a fractional order inductor, u_LIs the voltage of the fractional order inductor, β is the order of the fractional order inductor, L_βIs the inductance value of the fractional order inductance,

is the phase of a fractional order inductor and the order of the primary fractional order inductor is 1<β<2, order 0 of the secondary side fractional order inductor<β≤1。

Further, the differential relation between the voltage and the current of the primary side fractional order capacitor and the secondary side fractional order capacitor meets the following requirements:

the phase relation satisfies:

wherein i_CIs a current of fractional order capacitance u_CIs the voltage of the fractional order capacitor, α is the order of the fractional order capacitor, and 0<α≤1，C_αIs the capacitance value of the fractional order capacitor,

is the phase of the fractional order capacitance.

Compared with the prior art, the utility model, have following advantage and beneficial effect:

1. the system has simple structure and does not need a high-frequency voltage source.

2. The system efficiency and transmission power are insensitive to changes in transmission distance.

3. The system efficiency and transmission power can automatically adapt to the change of the electric field coupling coefficient and the resonant frequency.

4. The smaller the load resistance, the larger the interval in which the output power and the system efficiency constantly operate.

5. The wireless power transmission device is beneficial to wireless power transmission with larger power and longer distance, is particularly suitable for application occasions of high-power loads, and widens the application prospect of the wireless power transmission technology in the high-power fields of electric automobiles and the like.

Drawings

Fig. 1 is a schematic diagram of a specific system structure provided in the embodiment.

Fig. 2 is an equivalent circuit schematic diagram of a specific system provided in the embodiment.

Detailed Description

To further illustrate the aspects and features of the present invention, the following detailed description of the embodiments of the present invention is provided in conjunction with the accompanying drawings, but the invention is not limited thereto.

As shown in fig. 1 and fig. 2, the electric field coupling wireless power transmission system of the series autonomous fractional order circuit provided in this embodiment includes a fractional order transmitting circuit, a fractional order series receiving circuit, and a coupling capacitor metal plate, where the fractional order transmitting circuit and the fractional order series receiving circuit are connected in parallel through two coupling capacitor metal plates C_c1、C_c2Connecting, and further realizing wireless electric energy transmission in an electric field coupling mode; the fractional order transmitting circuit comprises a primary side fractional order inductor L which is connected in series and has the order more than 1_β1Primary side fractional order capacitor C with sum order number less than or equal to 1_α1The primary side fractional order inductance L_β1The circuit has the property of negative resistance, provides energy for the circuit, and the working frequency and the inductance value of the circuit can automatically follow the change of system parameters when the order is fixed, so that the transmission efficiency and the output power of the system have strong robustness to the change of the system parameters and are constant; the primary side fractional order inductor L_β1The device has the characteristic of constant apparent power and has two working modes: the fractional order inductor has a constant order, the working frequency and the inductance value automatically follow the change of system parameters to keep the fractional order inductor to work stably, and the working frequency is fixed, and the order and the inductance value automatically follow the change of the system parameters to keep the fractional order inductor to work stably; the fractional order series type receiving circuit comprises a secondary side fractional order inductor L which is connected in series and has an order less than or equal to 1_β2And a secondary side fractional order capacitor C with order less than or equal to 1_α2And a load R_L。

The working principle of the above system of this embodiment is: using a primary fractional order inductor L with an order greater than 1_β1And a fractional order capacitor C with an order of less than or equal to 1_α1And a fractional order series receiving circuit to form an autonomous system, so that a primary fractional order inductor L_β1The parameters of the system can automatically follow the system parameters to realize the constancy of the transmission efficiency and the power of the system; primary side fractional order inductance L_β1Providing energy to the circuit while the primary side is a fractional order inductor L_β1Preferentially work in a mode with fixed order, and the primary side fractional order inductor L_β1The operating frequency and inductance are automatically selected to maintain stable operation. Primary side fractional inductance L when system parameters change_β1The working frequency and the inductance value can automatically follow the change of the system, the transmission efficiency and the output power of the system are automatically kept constant, and when the change of the system parameters exceeds a set range, the primary side fractional order inductance L_β1And automatically switching to a mode with fixed working frequency to keep stable operation. Fractional order inductance L using secondary side with order less than or equal to 1_β2And a secondary side fractional order capacitor C with order less than or equal to 1_α2And a load R_LThe series connection forms a fractional order series type receiving circuit, the current gain is constant, the coupling interval of constant output power and transmission efficiency depends on the load resistance, and the load R_LThe smaller the resistance is, the longer the critical coupling distance is, which is beneficial to realizing the long-distance wireless power supply of a larger-power load, thereby widening the application prospect of the wireless power transmission technology in the large-power field of electric vehicles and the like.

According to the coupled mode theory, the coupled mode equation of the system is as follows:

in the formula, g₁、τ_2LGain ratio of the transmitting circuit and loss ratio of the receiving circuit, respectively, and g₁＝-(τ_Cα1+τ_Lβ1)，τ_2L＝τ_Cα2+τ_Lβ2+τ_LIn which τ is_Cα1、τ_Lβ1、τ_Cα2、τ_Lβ2、τ_LRespectively the loss rate of each element in the circuit,

where k is the electric field coupling coefficient, ω₁、ω₂The resonant angular frequencies of the transmitter and receiver, respectively, are expressed as follows:

the specific expression of the element loss rate of the fractional order transmitting circuit is as follows:

the load loss coefficient is:

the total loss factor of the fractional order series type receiving circuit is as follows:

the ratio of the load loss coefficient is:

the condition that the system has the steady state solution can be obtained by the formula (1) is as follows:

further, it is obtained from the formulae (1) and (9):

the system efficiency obtained is generally expressed as:

system output power general formula:

wherein:

in the formula I_Lβ1Is the effective value of the current of the fractional order inductor.

From equation (1), the system operating frequency is solved as:

when the primary side fractional order inductor works in a mode with a fixed order, β is made₁＝β₀Is constant, therefore the range of the mutual inductance coupling coefficient of the system obtained by the above formula when the primary side fractional order inductance order is fixed is:

k₀is the critical operating point of the system. When k is<k₀When the primary side fractional order inductor works in the order fixing mode, otherwise, the primary side fractional order inductor can not work stably without working frequency solution, so that the primary side fractional order inductor is automatically switched to the working frequency fixing mode, namely, omega is equal to omega₂。

When k is more than or equal to k₀While the primary side fractional order inductor operates in the fixed order mode β₁＝β₀Let k_mMaximum mutual inductance designed for the system. According to the equations (3) to (9), it can be found that when the system parameter satisfies the following equation:

τ_L＞＞τ_Cα2+τ_Lβ2(17)

then τ_L/τ_2LIs approximately constant and the transmission efficiency can be approximated as:

the output power is approximately:

S_Lβ1is the apparent power of the primary fractional order inductor, so as known from the above formula, k ≧ k₀The transmission efficiency and the output power of the time system are irrelevant to the mutual inductance and the resonant frequency.

When k is<k₀Then, from equations (9) - (14), the system transmission efficiency and output power can be obtained as:

according to the above analysis, the utility model provides a series connection type is from the electric field coupling wireless power transmission system of fractional order circuit, in the electric field coupling coefficient within range of design, no matter be the change of electric field coupling coefficient or resonant frequency's skew, the system can all realize the transmission of the invariable efficient of efficiency and output, and the invariable operating distance under the high-power load is far away, be favorable to realizing the more long-range wireless power supply of more high-power load, thereby greatly widen the application prospect of wireless power transmission technique in high-power fields such as electric automobile, this has great difference with traditional electric field coupling wireless power transmission system, the utility model discloses the advantage of system is obvious, is worth promoting.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be equivalent replacement modes, and all are included in the scope of the present invention.

Claims

1. A series type autonomous fractional order circuit electric field coupling wireless electric energy transmission system is characterized in that: the device comprises a fractional order transmitting circuit, a fractional order series receiving circuit and a coupling capacitance metal plate, wherein the fractional order transmitting circuit and the fractional order series receiving circuit are connected in parallel through two coupling capacitance metal plates (C)_c1、C_c2) Connecting, and further realizing wireless electric energy transmission in an electric field coupling mode; the fractional order transmitting circuit comprises a primary side fractional order inductor (L) which is connected in series and has an order greater than 1_β1) And a primary side fractional order capacitor (C) having a sum order of 1 or less_α1) The primary side fractional order inductance (L)_β1) Having the property of a negative resistance, providing energy to the circuit, said primary side fractional order inductance (L)_β1) Has a constant apparent power and has two modes of operation: the fractional order inductor has a constant order, the working frequency and the inductance value automatically follow the change of system parameters to keep the fractional order inductor to work stably, and the working frequency is fixed, and the order and the inductance value automatically follow the change of the system parameters to keep the fractional order inductor to work stably; the fractional order series type receiving circuit includes a secondary side fractional order inductance (L) having an order of 1 or less connected in series_β2) And a secondary side fractional order capacitor (C) with order less than or equal to 1_α2) And a load (R)_L) The coupling interval in which the current gain is constant and the output power and the transmission efficiency are constant depends on the load (R)_L) Resistance, load (R)_L) The smaller the resistance, the further the critical coupling distance.

2. The electric field coupling wireless power transmission system of the series autonomous fractional order circuit of claim 1, wherein: the primary side fractional order inductance (L)_β1) And secondary fractional order inductance (L)_β2) The voltage and current differential relation satisfies:

the phase relation satisfies:

3. The electric field coupling wireless power transmission system of the series autonomous fractional order circuit of claim 1, wherein: the primary side fractional order capacitor (C)_α1) And secondary fractional order capacitance (C)_α2) The voltage and current differential relation satisfies:

the phase relation satisfies:

is the phase of the fractional order capacitance.