CN114614580A - PT symmetry-based parallel multi-transmitting multi-receiving wireless power transmission system - Google Patents

PT symmetry-based parallel multi-transmitting multi-receiving wireless power transmission system Download PDF

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CN114614580A
CN114614580A CN202210372346.9A CN202210372346A CN114614580A CN 114614580 A CN114614580 A CN 114614580A CN 202210372346 A CN202210372346 A CN 202210372346A CN 114614580 A CN114614580 A CN 114614580A
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coil
transmitting
receiving
sub
symmetry
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张路
胡佳伟
杨奕
谢诗云
易皓鹏
李欢
叶谊
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Chongqing University of Technology
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
    • H02J50/12—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling of the resonant type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/10—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by the energy transfer between the charging station and the vehicle
    • B60L53/12—Inductive energy transfer
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/40—Circuit arrangements or systems for wireless supply or distribution of electric power using two or more transmitting or receiving devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y02T90/14—Plug-in electric vehicles

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  • Computer Networks & Wireless Communication (AREA)
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  • Inverter Devices (AREA)

Abstract

The invention relates to the technical field of wireless power transmission, and particularly discloses a PT (potential transformer) symmetry-based parallel multi-transmitting multi-receiving wireless power transmission system, wherein a plurality of parallel transmitting sub-coils are adopted at a transmitting end of the system, a plurality of parallel receiving sub-coils are adopted at a receiving end of the system, the system also provides parameter design under the circuit structure, conditions for keeping constant output power and constant transmission efficiency output of the system, and expressions of system transmission efficiency and output power, so that the actual requirements on the system transmission efficiency eta and the system output power P and the current stress of a switching tube in a high-frequency inverter are determined according to the expression of the system transmission efficiency eta and the expression of the system output power P, and the number m of transmitting coils and the number n of receiving coils are ensured, so that the system keeps good transmission performance.

Description

PT symmetry-based parallel multi-transmitting multi-receiving wireless power transmission system
Technical Field
The invention relates to the technical field of Wireless Power Transfer (WPT), in particular to a PT symmetry-based parallel multi-transmitting multi-receiving Wireless Power transmission system.
Background
A Wireless Power Transfer (WPT) system is connected with a transmitting end of electric energy without using a conducting wire, so that the problems of electric sparks, interface aging and the like generated in the traditional wired electric energy transmission process are solved, and the safety and the convenience in the aspect of electric energy transmission are greatly improved. In 2007, the MIT research team proposed a magnetic coupling resonant/wireless power transmission system that enables a 60W bulb to operate successfully with a transmission efficiency of 40% at a transmission distance of 2 m. The WPT system has been the focus of research in the field of power transmission since then.
A problem that has been urgently solved in the WPT system is a large change in output power and transmission power due to a shift in the relative positions of the transmitting coil and the receiving coil, that is, a shift problem. For this problem, there is a literature that a space-Time (PT) symmetry theory is applied to the WPT system for the first Time, and a nonlinear saturation gain-negative resistance is constructed by using an operational amplifier, so that when the coupling coefficient of a transmitting coil and a receiving coil is greater than a critical value, the output power and the transmission power of the system are kept constant. And the system is designed without double-ended communication between the transmitting end and the receiving end. In subsequent researches, a research team, which is first of the Zhang wave professor of the university of southern China, applies the PT symmetry principle to the WPT system for many times, and publishes a plurality of academic achievements at home and abroad, so that the application of the PT symmetry principle to the WPT system is promoted. The literature proposes a double-coupling WPT system based on electric field coupling and magnetic field coupling, which uses PT symmetry principle to realize strong robustness of the system. And the theory analysis is carried out on the whole system through the coupling mode theory, so that the expression of the output power and the transmission efficiency of the system is deduced. Finally, a WPT system which keeps constant output power of 70W and constant transmission efficiency of 70% in the range of 1.4m is designed. In other documents, the transmission performance of a WPT system based on the PT symmetry principle is analyzed based on a coupled-mode theory (CMT), and a jacobian matrix is used to determine the stability of the whole system. Theories show that in a strong coupling area, the WPT system can realize constant output power and constant transmission power, and an unmanned aerial vehicle wireless charging system with the transmission efficiency of 93.6% is designed. The method is also applied to the field of wireless charging of electric automobiles, a circuit model of a WPT system based on PT symmetry is established, and a critical coupling coefficient for keeping constant output power and transmission efficiency of the WPT system under SS topology is deduced. A WPT system consisting of one transmitting coil and two receiving coils is designed, and the result shows that the transmission efficiency can be remarkably improved by the aid of the multiple receiving coils. In the prior art, under a PT-symmetry-based WPT system, a relay coil is introduced, a corresponding coupling model and a circuit steady-state model are established, and experimental platforms including one relay coil and two relay coils are respectively established, and the results show that the addition of the relay coil can effectively prolong the transmission distance for maintaining constant output power and constant transmission efficiency, but the transmission efficiency of the whole system is slightly reduced. Still another document proposes a control strategy combining self-oscillation and pulse width modulation on the basis of a WPT system based on PT symmetry principle. When the WPT system is in a strong coupling state, the WPT system is in a PT symmetrical state, and constant output power and constant transmission efficiency can be achieved. When the WPT system is in a weak coupling state, namely a broken PT symmetrical state, a pulse width modulation strategy is adopted on a primary side, so that the output power and the transmission efficiency are kept stable.
Most of the documents above are directed to theoretically deriving and determining stability of a single transmitting coil and a single receiving coil WPT system based on PT symmetry principle, and a circuit model of a one-to-many WPT system based on PT symmetry principle is proposed, but none of the above contents has studied influence of the number of coils of multiple transmitting coils and multiple receiving coils based on PT symmetry on system output power and transmission efficiency, and the wireless power transmission technology based on PT symmetry principle cannot be developed to multiple receiving coils and multiple receiving coils with practical significance.
Disclosure of Invention
The invention provides a PT symmetry-based parallel multi-transmitting multi-receiving wireless power transmission system, which solves the technical problems that: how to apply a multi-transmitting multi-receiving coil in a PT symmetry based wireless power transmission system and maintain good output power and transmission efficiency.
In order to solve the technical problems, the invention provides a PT-based symmetrical parallel multi-transmitting multi-receiving wireless power transmission system, which comprises a transmitting end and a receiving end, wherein the transmitting end is connected with the receiving end;
the transmitting end comprises a direct-current power supply, a high-frequency inverter, a parallel multi-transmitting coil circuit, a current sensor and a zero-crossing comparator, wherein the direct-current power supply, the high-frequency inverter and the parallel multi-transmitting coil circuit are sequentially connected with one another; the direct current power supply obtains high-frequency voltage after full-bridge inversion of the high-frequency inverter, then obtains an output current signal through induction of the current sensor, inputs the output current signal into the zero-crossing comparator, feeds back a corresponding zero-crossing signal to the driving module through the zero-crossing comparator, and generates a corresponding driving signal to act on the high-frequency inverter so as to keep the output voltage and the output current of the high-frequency inverter in the same phase;
the receiving end comprises a parallel multi-receiving coil circuit, a rectifier and an equivalent load resistor R which are connected in sequenceL；
The parallel multi-transmitting coil circuit comprises m transmitting sub-coil circuits which are connected in parallel between two output ends of the high-frequency inverter, each transmitting sub-coil circuit comprises a transmitting sub-coil and a primary side compensation capacitor which are connected in series, and m is more than or equal to 2; the parallel multi-receiving coil circuit comprises n receiving sub-coil circuits connected between two input ends of the rectifier in parallel, each receiving sub-coil circuit comprises a receiving sub-coil and a secondary compensation capacitor which are connected in series, and n is larger than or equal to 2.
Preferably, the specification parameters of the m emitter sub-coils are consistent, namely:
Rp1＝…Rpi…＝Rpm＝Rp,Xp1＝…Xpi…＝Xpm,Lp1＝…Lpi…＝Lpm＝Lp，
Rpiis the parasitic resistance of the ith transmitter coil,
Figure BDA0003589296030000031
is the impedance, L, of the primary side loop in which the i-th transmitter coil is locatedpiIs the self-inductance of the i-th emitter coil, CpiThe system is characterized in that the system is an ith primary side resonance capacitor connected with an ith transmitter coil in series, i is 1,2 … m, and omega is the working angular frequency of the system;
the specification parameters of the n receiver sub-coils are consistent, namely:
Rs1＝…Rsk…＝Rsn＝Rs,Xs1＝…Xsk…＝Xsn,Ls1＝…Lsk…＝Lsm＝Ls，
Rskis the parasitic resistance of the kth receiver sub-coil,
Figure BDA0003589296030000032
is the impedance of the secondary loop in which the kth receiver coil is located, LskIs the self-inductance of the kth receiver coil, CskA kth secondary side resonance capacitor connected in series with the kth receiver sub-coil, wherein k is 1,2 … n;
the coupling coefficients of any one transmitting sub-coil and any one receiving sub-coil are equal to each other and are K, and the mutual inductance between any one transmitting sub-coil and any one receiving sub-coil is equal to each other and is Mik＝Mki＝MmnThe natural resonant frequency of the resonant circuit in which the ith transmitter coil is positioned is omegapiThe natural resonant frequency of the resonant circuit in which the kth receiver coil is located is omegask，ωpi＝ωsk＝ω0，i＝1,2…m，k＝1,2…n；
Preferably, the operating angular frequency ω of the system is designed as:
Figure BDA0003589296030000041
Figure BDA0003589296030000042
preferably, so that ω is within the real number range, the system further satisfies:
Figure BDA0003589296030000043
Kais the critical coupling coefficient.
Preferably, K ≧ K is selected to maintain constant output power, constant transmission efficiency outputa。
Preferably, the system transmission efficiency
Figure BDA0003589296030000044
System output power
Figure BDA0003589296030000045
VpA fundamental component of the output voltage for the high frequency inverter;
and determining the number m of transmitting coils and the number n of receiving coils according to the expression of the system transmission efficiency eta, the expression of the system output power P, the actual requirements on the system transmission efficiency eta and the system output power P and the current stress of a switching tube in the high-frequency inverter.
The invention provides a PT symmetrical parallel multi-transmitting multi-receiving wireless power transmission system, different from various PT symmetrical wireless electric energy transmission systems in the background art, the transmitting end of the system adopts a plurality of transmitting sub-coils which are connected in parallel, the receiving end adopts a plurality of receiving sub-coils which are connected in parallel, the system also provides parameter design under the circuit structure, and the system keeps constant output power and constant transmission efficiency output, and also provides expressions of system transmission efficiency and output power, so that according to the expression of system transmission efficiency eta and the expression of system output power P, and determining the number m of transmitting coils and the number n of receiving coils according to the actual requirements on the transmission efficiency eta and the output power P of the system and the current stress of a switching tube in the high-frequency inverter, so that the system keeps good transmission performance.
Drawings
FIG. 1 is a schematic diagram of an implementation of a nonlinear gain provided by an embodiment of the present invention;
fig. 2 is an overall structural diagram of a PT-based symmetric parallel multi-transmission multi-reception wireless power transmission system according to an embodiment of the present invention;
fig. 3 is an equivalent circuit diagram of a parallel multi-transmitting multi-receiving wireless power transmission system based on PT symmetry according to an embodiment of the present invention;
FIG. 4 is a diagram of the relationship between the output power and the number m of transmitting coils and the number n of receiving coils in the simulation provided by the embodiment of the present invention;
FIG. 5 shows a critical coupling coefficient K in a simulation provided by an embodiment of the present inventionaA relation graph with the number m of transmitting coils and the number n of receiving coils;
FIG. 6 is a graph comparing output power of a one-to-one type system and a three-to-two type system in a simulation provided by an embodiment of the present invention;
FIG. 7 is a graph comparing transmission efficiency of a one-to-one type system and a three-to-two type system in a simulation according to an embodiment of the present invention.
Detailed Description
The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, which are given solely for the purpose of illustration and are not to be construed as limitations of the invention, including the drawings which are incorporated herein by reference and for illustration only and are not to be construed as limitations of the invention, since many variations thereof are possible without departing from the spirit and scope of the invention.
The PT symmetrical system is kept constant under time reversal and space reversal. The WPT system under PT symmetry must satisfy:
(1) the natural resonant frequencies at the two ends of the secondary side are equal;
(2) contains a nonlinear saturation gain-negative resistance (whose voltage is opposite to the current).
The system proposed in this embodiment should meet the above requirements. For realizing the negative resistance, as shown in the schematic diagram of fig. 1, the present embodiment adopts a high-frequency inverter (formed by connecting 4 MOS transistors Q1, Q2, Q3, and Q4) to the dc power supply UdInverting to obtain high-frequency voltage, and obtaining output current signal i by current sensorpAnd then the zero-crossing comparator feeds the zero-crossing signal back to a driving module of the high-frequency inverter to generate a corresponding driving signal. Through the operation, the output voltage and the output current of the full-bridge inverter can be kept in the same phase, so that the full-bridge inverter is equivalent to a negative resistance-PN。
Based on this, the embodiment of the present invention provides a PT-symmetry-based parallel multi-transmitting multi-receiving wireless power transmission system, which includes a transmitting end and a receiving end. As shown in the overall structure diagram of fig. 2, the transmitting terminal includes a direct current power supply DC, a high frequency inverter, a parallel multi-transmitting coil circuit, and a current sensor and a zero-crossing comparator sequentially connected between the output terminal and the driving terminal of the high frequency inverter. The direct current power supply obtains high-frequency voltage after full-bridge inversion of the high-frequency inverter, then obtains an output current signal through induction of the current sensor, inputs the output current signal into the zero-crossing comparator, feeds back a corresponding zero-crossing signal to the driving module through the zero-crossing comparator, and generates a corresponding driving signal to act on the high-frequency inverter so as to enable the output voltage and the output current of the high-frequency inverter to keep the same phase. The receiving end comprises a parallel multi-receiving coil circuit, a rectifier and an equivalent load resistor R which are connected in sequenceL。
As shown in an equivalent circuit diagram of FIG. 3, the parallel multi-transmitting coil circuit comprises m transmitting sub-coil circuits connected in parallel between two output ends of the high-frequency inverter, each transmitting sub-coil circuit comprises a transmitting sub-coil and a primary side compensation capacitor which are connected in series, and m is larger than or equal to 2. The parallel multi-receiving coil circuit comprises n receiving sub-coil circuits which are connected between two input ends of the rectifier in parallel, each receiving sub-coil circuit comprises a receiving sub-coil and a secondary side compensation capacitor which are connected in series, and n is more than or equal to 2.
Wherein L isPi,RPiSelf-inductance and self-inductance of the transmitter coil (i-th transmitter coil) in the i-th primary-side loop, respectivelyParasitic resistance, CPiFor series compensation capacitors in the i-th primary side loop, Lsk,RskRespectively, the self-inductance and the parasitic resistance of the receiver coil (kth receiver sub-coil) in the kth secondary side loop, CskFor series compensation capacitors in the kth secondary side loop, MikFor mutual inductance between the transmitter coil in the ith primary side loop and the receiver coil in the kth secondary side loop, ipiFor the coil current in the ith primary-side loop, iskIs the coil current in the kth secondary side loop, ω is the operating angular frequency of the system,
Figure BDA0003589296030000061
Figure BDA0003589296030000062
is the impedance of the ith primary-side loop,
Figure BDA0003589296030000063
the impedance of the kth secondary-side loop is 1,2, … …, m, k is 1,2, … …, n.
According to the KVL law, the equivalent circuit diagram shown in fig. 3 can be given by the following equation:
Figure BDA0003589296030000064
Figure BDA0003589296030000071
for the above system of equations, the present embodiment makes the following assumptions:
(1) the coupling coefficients of any one transmitting sub-coil and any one receiving sub-coil are equal to K;
(2) decoupling processing is carried out on a transmitting coil at the primary side and a receiving coil at the secondary side, namely mutual inductance cannot be generated between coils at the same end;
(3) the specification parameters of all the transmitter sub-coils are consistent, and the specification parameters of all the receiver sub-coils are also consistent.
From the above assumptions:
Rp1＝…Rpi…＝Rpm＝Rp,Xp1＝…Xpi…＝Xpm,Lp1＝…Lpi…＝Lpm＝Lp，i＝1,2…m；
Rs1＝…Rsk…＝Psn＝Rs,Xs1＝…Xsk…＝Xsn,Ls1＝…Lsk…＝Lsm＝Ls，k＝1,2…n；
Mik＝Mki＝Mmn＝M，i＝1,2…m，k＝1,2…n。
based on the above assumptions, equations (1) and (2) can be simplified as follows:
Figure BDA0003589296030000072
suppose the natural resonant frequency of the ith transmitting coil loop is ωpi(i is 1,2 … …, m), and the natural resonant frequency of the kth receiver coil loop is ωsk(k is 1,2, … …, n) and satisfies ωpi＝ωsk＝ω0Then equation (3) can be converted to:
Figure BDA0003589296030000073
if a real solution to the above equation is desired, it must be satisfied:
Figure BDA0003589296030000074
separating the real part from the imaginary part in equation (5) above, one can then obtain:
Figure BDA0003589296030000081
working systemWhen PT symmetry principle is satisfied, ω ≠ ω0Then, equation (6) is further simplified to obtain:
Figure BDA0003589296030000082
by substituting formula (7) into formula (6), two solutions for ω can be obtained:
Figure BDA0003589296030000083
formula (8) is further simplified to:
Figure BDA0003589296030000084
to make the above formula ω within the real number range, there are:
Figure BDA0003589296030000085
at this time, KaIs the critical coupling coefficient. When the coupling coefficient K is more than or equal to KaEquation (4) is:
Figure BDA0003589296030000086
then, the following equation (11) can be solved:
Figure BDA0003589296030000087
the transmission efficiency of the WPT system in PT symmetry is:
Figure BDA0003589296030000088
the output power is:
Figure BDA0003589296030000091
Vpis the fundamental component of the high frequency inverter output voltage.
From equations (13) and (14), when the system is in the PT symmetric state, the transmission efficiency and the output power of the system are independent of the coupling coefficient K. As can be seen from equation (13), increasing the number of receiving coils n improves the transmission efficiency. As can be seen from equation (14), when the number n of receiving coils is not changed, increasing the number m of transmitting coils increases the transmission power. As can be seen from equation (10), when the number n of receiving coils is not changed, increasing the number m of transmitting coils can significantly reduce the critical coupling coefficient Ka. Specifically, as can be seen from equations (13) and (14), when the coupling coefficient K.gtoreq.KaThe transmission power of the proposed system is only related to the self-inductance of the transmitting side coil, the self-inductance of the receiving coil, the number m of turns of the transmitting coil, the number n of turns of the receiving coil, the input voltage and the load resistance, and is not related to the coupling coefficient K, while the transmission efficiency of the system is only related to the parasitic resistance and self-inductance of the transmitting coil, the parasitic resistance and self-inductance of the receiving coil, and the load resistance.
Therefore, when a WPT system based on PT symmetry is designed, reasonable transmitting coil number m and receiving coil number n can be selected, so that the transmission efficiency and the output power of the WPT system are remarkably improved. However, the excessive number of the transmitting coils will increase the current of the switch tube in the full-bridge inversion. Therefore, when designing a symmetrical WPT system based on PT, the current stress of the switch tube is also considered so as to avoid burning the switch tube.
Next, performing joint contrast simulation on the WPT systems of one-to-one type and three-to-two type based on the PT symmetry principle in Simulink simulation software to verify the conclusion. To obtain a smaller critical coupling coefficient KaHere taking the load R L5 Ω. The natural resonance frequency is 85kHz according to the industry standard of electric automobiles. Specific simulation parameters are shown in table 1, and the parameters of the proposed one-to-one and three-to-two WPT systems differ only in the number of transmit turns m and the number of receive turns n.
TABLE 1 System parameters
Figure BDA0003589296030000092
Figure BDA0003589296030000101
The output power and the critical coupling coefficient K can be obtained by MATLAB according to the simulation parametersaAnd m, n. From the graph of the output power with respect to the number m of the transmitting coils and the number n of the receiving coils shown in FIG. 4 and the critical coupling coefficient K shown in FIG. 5aThe relation graph of the number m of the transmitting coils and the number n of the receiving coils shows that the improvement of the number m of the transmitting coils can obviously increase the output power and can also obviously reduce the critical coupling coefficient KaThis is consistent with the conclusions set forth.
As can be seen from the output power comparison graph shown in fig. 6 and the transmission efficiency graph shown in fig. 7, the transmission efficiency and the output power of the three-to-two WPT system based on PT symmetry are significantly superior to those of the conventional one-to-one WPT system. The transmission power of a three-to-two WPT system is about 75% higher than that of a one-to-one WPT in terms of output power. From the transmission efficiency, the transmission efficiency of the three-to-two WPT system is about 12% higher than that of the one-to-one WPT system, and the three-to-two WPT system has good transmission performance.
To sum up, the parallel multi-transmitting multi-receiving wireless power transmission system based on PT symmetry provided by the embodiments of the present invention is different from various existing wireless power transmission systems based on PT symmetry in that the system employs a plurality of parallel transmitting sub-coils at the transmitting end and a plurality of parallel receiving sub-coils at the receiving end, and the system also provides parameter design under the circuit structure, and conditions that the system maintains constant output power and constant transmission efficiency output (K is greater than or equal to K)a) The expression of system transmission efficiency and output power is also given
Figure BDA0003589296030000102
So that the system transmission efficiency eta is expressed,The expression of the system output power P, the actual requirements on the system transmission efficiency eta and the system output power P, and the current stress of a switching tube in the high-frequency inverter determine the transmitting coil number m and the receiving coil number n, so that the system keeps good transmission performance.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to 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 construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims (6)

1. A PT symmetry-based parallel multi-transmitting multi-receiving wireless power transmission system is characterized by comprising a transmitting end and a receiving end;
the transmitting end comprises a direct-current power supply, a high-frequency inverter, a parallel multi-transmitting coil circuit, a current sensor and a zero-crossing comparator, wherein the direct-current power supply, the high-frequency inverter and the parallel multi-transmitting coil circuit are sequentially connected with one another; the direct current power supply obtains high-frequency voltage after full-bridge inversion of the high-frequency inverter, then obtains an output current signal through induction of the current sensor, inputs the output current signal into the zero-crossing comparator, feeds back a corresponding zero-crossing signal to the driving module through the zero-crossing comparator, and generates a corresponding driving signal to act on the high-frequency inverter so as to keep the output voltage and the output current of the high-frequency inverter in the same phase;
the receiving end comprises a parallel multi-receiving coil circuit, a rectifier and an equivalent load resistor R which are connected in sequenceL；
The parallel multi-transmitting coil circuit comprises m transmitting sub-coil circuits which are connected in parallel between two output ends of the high-frequency inverter, each transmitting sub-coil circuit comprises a transmitting sub-coil and a primary side compensation capacitor which are connected in series, and m is more than or equal to 2; the parallel multi-receiving coil circuit comprises n receiving sub-coil circuits connected between two input ends of the rectifier in parallel, each receiving sub-coil circuit comprises a receiving sub-coil and a secondary compensation capacitor which are connected in series, and n is larger than or equal to 2.
2. The parallel multi-transmission multi-reception wireless power transmission system based on PT symmetry of claim 1,
the specification parameters of the m emitter sub-coils are consistent, namely:
Rp1＝…Rpi…＝Rpm＝Rp，Xp1＝…Xpi…＝Xpm，Lp1＝…Lpi…＝Lpm＝Lp，
Rpiis the parasitic resistance of the ith transmitter coil,
Figure FDA0003589296020000011
is the impedance, L, of the primary side loop in which the i-th transmitter coil is locatedpiIs the self-inductance of the i-th emitter coil, CpiThe system is characterized in that the system is an ith primary side resonance capacitor connected with an ith transmitter coil in series, i is 1,2 … m, and omega is the working angular frequency of the system;
the specification parameters of the n receiver sub-coils are consistent, namely:
Rs1＝…Rsk…＝Rsn＝Rs，Xs1＝…Xsk…＝Xsn，Ls1＝…Lsk…＝Lsm＝Ls，
Rskis the parasitic resistance of the kth receiver sub-coil,
Figure FDA0003589296020000021
is the impedance of the secondary loop in which the kth receiver coil is located, LskIs the self-inductance of the kth receiver coil, CskA kth secondary side resonance capacitor connected in series with the kth receiver sub-coil, wherein k is 1,2 … n;
the coupling coefficients of any one transmitting sub-coil and any one receiving sub-coil are equal to each other and are K, and the mutual inductance between any one transmitting sub-coil and any one receiving sub-coil is equal to each other and is Mik＝Mki＝MmnNatural resonance of the resonant circuit in which the ith transmitter coil is located (M)Vibration frequency of omegapiThe natural resonant frequency of the resonant circuit in which the kth receiver coil is located is omegask，ωpi＝ωsk＝ω0，i＝1，2…m，k＝1，2…n。
3. The PT-symmetry-based parallel multi-transmission multi-reception wireless power transmission system of claim 2, wherein an operating angular frequency ω of the system is designed as:
Figure FDA0003589296020000022
Figure FDA0003589296020000023
4. the PT symmetry based parallel multi-transmit multi-receive wireless power transmission system of claim 3, further satisfying:
Figure FDA0003589296020000024
Kais the critical coupling coefficient.
5. The parallel multi-transmission multi-reception wireless power transmission system based on PT symmetry of claim 3, wherein: k is more than or equal to Ka。
6. The PT-symmetry-based parallel multi-transmission multi-reception wireless power transmission system of claim 4, wherein system transmission efficiency
Figure FDA0003589296020000025
System output power
Figure FDA0003589296020000026
Figure FDA0003589296020000027
VpA fundamental component of the output voltage for the high frequency inverter;
and determining the number m of transmitting coils and the number n of receiving coils according to the expression of the system transmission efficiency eta, the expression of the system output power P, the actual requirements on the system transmission efficiency eta and the system output power P and the current stress of a switching tube in the high-frequency inverter.
CN202210372346.9A 2022-04-11 2022-04-11 PT symmetry-based parallel multi-transmitting multi-receiving wireless power transmission system Pending CN114614580A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117081273A (en) * 2023-10-18 2023-11-17 北京建筑大学 Three-coil wireless power transmission system, detection method and control method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117081273A (en) * 2023-10-18 2023-11-17 北京建筑大学 Three-coil wireless power transmission system, detection method and control method thereof
CN117081273B (en) * 2023-10-18 2023-12-15 北京建筑大学 Three-coil wireless power transmission system, detection method and control method thereof

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