CN114221452B - Electric automobile wireless charging device with battery energy balance function and control method thereof - Google Patents

Electric automobile wireless charging device with battery energy balance function and control method thereof Download PDF

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Publication number
CN114221452B
CN114221452B CN202111301907.8A CN202111301907A CN114221452B CN 114221452 B CN114221452 B CN 114221452B CN 202111301907 A CN202111301907 A CN 202111301907A CN 114221452 B CN114221452 B CN 114221452B
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switching tube
circuit
energy
switch
battery
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CN114221452A (en
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黄琳璐
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China Three Gorges University CTGU
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China Three Gorges University CTGU
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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
    • 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
    • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0014—Circuits for equalisation of charge between batteries
    • H02J7/0019—Circuits for equalisation of charge between batteries using switched or multiplexed charge circuits
    • 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
    • H02J7/04—Regulation of charging current or voltage
    • 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

An electric automobile wireless charging device with a battery energy balancing function and a control method thereof are provided, wherein the device comprises a power supply side circuit, a receiving circuit and an balancing circuit. The power supply side circuit comprises a first rectifying circuit, an LC filter circuit and an inverter circuit, wherein the power frequency power supply AC is connected with the first rectifying circuit, the first rectifying circuit is connected with the LC filter circuit, the LC filter circuit is connected with the inverter circuit, and the inverter circuit is connected with the transmitting coil L1. The receiving circuit comprises a second rectifying circuit, a variable capacitor and a series battery pack, wherein the receiving coil L2 is connected with the second rectifying circuit, the second rectifying circuit is connected with the variable capacitor, and the variable capacitor is connected with the series battery pack. The equalization circuit comprises an equalization unit and a switch array, wherein the equalization unit is connected with the switch array, and the switch array is connected with the series battery pack. The wireless charging device and the control method can balance the energy of the battery pack while charging, thereby reducing the energy loss caused by the process of charging and balancing, and having the advantages of convenient use, safety, reliability, rapidness and convenience.

Description

Electric automobile wireless charging device with battery energy balance function and control method thereof
Technical Field
The invention belongs to the technical field of electric automobile charging, and particularly relates to an electric automobile wireless charging device with a battery energy balancing function and a control method thereof.
Background
Nowadays, new energy automobiles using lithium batteries as power sources are widely used. The plug-in charging mode needs joint matching, is limited by the position and distance of a charging pile, and easily has potential safety hazards. The wireless charging mode can be used for non-contact charging, and safety and convenience are greatly improved. However, the primary and secondary coils cannot be matched particularly well, so that the charging transmission efficiency is low. Wireless charging is typically slow on electric vehicles, where the power is not large enough to be sufficient, but much longer than is required by conventional techniques.
Existing wireless charging techniques often ignore battery cell inconsistencies and consider the battery pack as a whole. This charging may have a problem in that a part of the battery is full and a part of the battery is not full. At this time, the charged batteries are charged continuously, and the charged batteries are over-charged, so that potential safety hazards of explosion are brought. Therefore, the charging needs to be stopped, which results in that a part of batteries are not fully charged, and the chargeable capacity of the part of batteries is not fully utilized, so that the available capacity is idle and wasted, and the endurance mileage of the new energy automobile is limited. Also, during the running of the new energy automobile, all the batteries are regarded as a whole, and the inconsistency of the battery cells is ignored. Thus, some batteries are depleted during travel, but some batteries remain. If the vehicle continues to run at this time, the battery with the depleted electric quantity is subject to the problem of excessive use of the battery, so that the service life of the electric vehicle is shortened, and therefore, the vehicle should stop running at this time, and the running mileage of the new energy vehicle is limited.
Disclosure of Invention
In order to solve the technical problems, the invention provides an electric vehicle wireless charging device with a battery energy balancing function and a control method thereof. Compared with the prior art, the wireless charging device and the control method can balance the energy of the battery pack while charging, so that the energy loss caused by the process of charging and balancing is reduced, and the wireless charging device and the control method have the advantages of convenience in use, safety, reliability, rapidness and convenience.
The technical scheme adopted by the invention is as follows:
an electric vehicle wireless charging device with a battery energy equalization function, comprising: a power supply side circuit, a receiving circuit, and an equalizing circuit;
the power supply side circuit comprises a first rectifying circuit, an LC filter circuit and an inverter circuit, wherein the power frequency power supply AC is connected with the first rectifying circuit, the first rectifying circuit is connected with the LC filter circuit, the LC filter circuit is connected with the inverter circuit, and the inverter circuit is connected with the transmitting coil L1;
the receiving circuit comprises a second rectifying circuit, a variable capacitor and a series battery pack, wherein the receiving coil L2 is connected with the second rectifying circuit, the second rectifying circuit is connected with the variable capacitor, and the variable capacitor is connected with the series battery pack;
the equalization circuit comprises an equalization unit and a switch array, wherein the equalization unit is connected with the switch array, and the switch array is connected with the series battery pack.
The first rectifying circuit comprises diodes VD1, VD2, VD3 and VD4; the LC filter circuit comprises an inductor Lf and a capacitor C1; the inverter circuit comprises switching tubes VT1, VT2, VT3 and VT4;
one side of the power frequency power supply AC is respectively connected with the anode of the diode VD1 and the cathode of the diode VD3, and the other side of the power frequency power supply AC is respectively connected with the anode of the diode VD2 and the cathode of the diode VD4; the cathode of the diode VD1 and the cathode of the diode VD2 are both connected with one end of an inductor Lf, the other end of the inductor Lf is connected with one end of a capacitor C1, and the other end of the capacitor C1 is respectively connected with the anode of the diode VD3 and the anode of the diode VD4;
one end of the capacitor C1 is respectively connected with the source electrode of the switch tube VT1 and the source electrode of the switch tube VT2, the other end of the capacitor C1 is respectively connected with the drain electrode of the switch tube VT3 and the drain electrode of the switch tube VT4, the drain electrode of the switch tube VT1 is connected with the source electrode of the switch tube VT3, the drain electrode of the switch tube VT2 is connected with the source electrode of the switch tube VT4, the drain electrode of the switch tube VT1 is connected with one end of the transmitting coil L1, and the other end of the transmitting coil L1 is connected with the source electrode of the switch tube VT4.
The second rectifying circuit comprises a diode VD7, a diode VD8, a diode VD9 and a diode VD10, the variable capacitor comprises a capacitor C2, and the switching tubes SC1, SC2, SC3 and SC4 are connected in series, and the series battery pack comprises n batteries B1, B2 and B3 which are connected in series;
one end of the receiving coil L2 is respectively connected with the anode of the diode VD7 and the cathode of the diode VD9, and the other end of the receiving coil L2 is respectively connected with the anode of the diode VD8 and the cathode of the diode VD 10;
one end of a capacitor C2 is respectively connected with the drain electrode of the switching tube SC1 and the drain electrode of the switching tube SC3, the other end of the capacitor C2 is respectively connected with the source electrode of the switching tube SC2 and the source electrode of the switching tube SC4, the source electrode of the switching tube SC1 is respectively connected with the drain electrode of the switching tube SC2 and the cathode of the diode VD8, and the source electrode of the switching tube SC3 is respectively connected with the drain electrode of the switching tube SC4 and the anode of the diode VD 10;
the cathode of the diode VD8 is connected with the anode of the series battery, and the anode of the diode VD10 is connected with the cathode of the series battery.
The equalization unit comprises a switching tube SH, a switching tube SL, a switch SE and an inductor L3, wherein the drain electrode of the switching tube SH is connected with the output anode of the second rectifying circuit, the source electrode of the switching tube SL is connected with the output anode of the second rectifying circuit, the source electrode of the switching tube SH is respectively connected with the drain electrode of the switching tube SL, one end of the switch SE and one end of the inductor L3, the other end of the switch SE and the other end of the inductor L3 are respectively connected with one side terminal PM of a switch array, and the switch array comprises N-1 switches S1, S2 and S3 N-1 One end of any switch is connected with the terminal PM, and the other end of the switch S1, the other end of the switch S2 and the switch S3The other end N - 1 The other end is respectively connected with a battery B1 negative electrode, a battery B2 negative electrode and a battery B3 negative electrode.
The positive electrode of the battery B1 is connected with the output positive electrode of the second rectifying circuit through a switch Sup, and the negative electrode of the battery BN is connected with the output negative electrode of the second rectifying circuit through a switch SDown.
The invention relates to an electric automobile wireless charging device with a battery energy balance function and a control method thereof, which have the following technical effects:
1) The non-contact charging mode reduces potential safety hazards caused by the connector, and is simple, convenient and efficient.
2) The receiving end of the invention adopts the electronic capacitor, and the size of the capacitor can be adjusted, thereby tracking the frequency of the transmitting end and realizing the maximization of the charging efficiency.
3) The invention only uses the combination of the equalization unit and the switch array, reduces the volume and the quality of the system, and the equalization circuit can also be carried out in the charging process, thereby reducing the secondary loss caused by the prior charging and the equalization.
4) The equalization circuit can ensure that the battery pack keeps electric quantity consistency in the charging process, and can realize secondary distribution of the energy of the battery pack in an idle state. Further, the energy from the power supply side can be charged into part of the batteries in the battery pack, so that the balance during charging is realized, and the extra loss caused by the existing charge and equalization is reduced.
Drawings
Fig. 1 is a schematic structural diagram of a wireless charging device for an electric vehicle according to the present invention.
Fig. 2 is a circuit diagram of a transmitting portion of the wireless charging circuit of the present invention.
Fig. 3 is a circuit diagram of a receiving portion of the wireless charging circuit of the present invention.
Fig. 4 is a circuit diagram of an equalization circuit portion of the present invention.
Fig. 5 is an overall circuit diagram of the wireless charging device for the electric automobile.
Fig. 6 is a schematic diagram of a charging process when the battery energies are consistent.
FIG. 7 (a) is a schematic diagram illustrating the operation of the equalization circuit;
fig. 7 (b) is a schematic diagram of the equalization circuit in state two.
Fig. 8 (a) is a schematic diagram of the operation of the equalization circuit state (1);
fig. 8 (b) is a schematic diagram of the operation of the equalization circuit state (2);
fig. 8 (c) is a schematic diagram of the operation of the equalization circuit state (3);
fig. 8 (d) is a schematic diagram of the operation of the equalization circuit state (4).
Fig. 9 is a charge mode diagram one of the equalization process;
fig. 10 is a charge pattern diagram two of the equalization process.
FIG. 11 is a flow chart of the mode selection of operation of the present invention.
Detailed Description
As shown in fig. 1, an electric vehicle wireless charging device with a battery energy balancing function includes a power supply side circuit, a receiving circuit, and an balancing circuit. The power supply side circuit comprises a first rectifying circuit, an LC filter circuit and an inverter circuit, wherein the power frequency power supply AC is connected with the first rectifying circuit, the first rectifying circuit is connected with the LC filter circuit, the LC filter circuit is connected with the inverter circuit, and the inverter circuit is connected with the transmitting coil L1. The receiving circuit comprises a second rectifying circuit, a variable capacitor and a series battery pack, wherein the receiving coil L2 is connected with the second rectifying circuit, the second rectifying circuit is connected with the variable capacitor, and the variable capacitor is connected with the series battery pack. The equalization circuit comprises an equalization unit and a switch array, wherein the equalization unit is connected with the switch array, and the switch array is connected with the series battery pack.
As shown in fig. 2, the first rectifying circuit includes diodes VD1, VD2, VD3, VD4; the LC filter circuit comprises an inductor Lf and a capacitor C1; the inverter circuit includes switching transistors VT1, VT2, VT3, VT4. One side of the power frequency power supply AC is respectively connected with the anode of the diode VD1 and the cathode of the diode VD3, and the other side of the power frequency power supply AC is respectively connected with the anode of the diode VD2 and the cathode of the diode VD4; the cathode of the diode VD1 and the cathode of the diode VD2 are both connected with one end of an inductor Lf, the other end of the inductor Lf is connected with one end of a capacitor C1, and the other end of the capacitor C1 is respectively connected with the anode of the diode VD3 and the anode of the diode VD 4. One end of the capacitor C1 is respectively connected with the source electrode of the switch tube VT1 and the source electrode of the switch tube VT2, the other end of the capacitor C1 is respectively connected with the drain electrode of the switch tube VT3 and the drain electrode of the switch tube VT4, the drain electrode of the switch tube VT1 is connected with the source electrode of the switch tube VT3, the drain electrode of the switch tube VT2 is connected with the source electrode of the switch tube VT4, the drain electrode of the switch tube VT1 is connected with one end of the transmitting coil L1, and the other end of the transmitting coil L1 is connected with the source electrode of the switch tube VT4.
As shown in fig. 3, the second rectifying circuit includes a diode VD7, a diode VD8, a diode VD9, and a diode VD10, the variable capacitance includes a capacitor C2, and the switching transistors SC1, SC2, SC3, and SC4, and the series battery pack includes n series-connected batteries B1, B2, and B3. One end of the receiving coil L2 is respectively connected with the anode of the diode VD7 and the cathode of the diode VD9, and the other end of the receiving coil L2 is respectively connected with the anode of the diode VD8 and the cathode of the diode VD 10. One end of the capacitor C2 is respectively connected with the drain electrode of the switching tube SC1 and the drain electrode of the switching tube SC3, the other end of the capacitor C2 is respectively connected with the source electrode of the switching tube SC2 and the source electrode of the switching tube SC4, the source electrode of the switching tube SC1 is respectively connected with the drain electrode of the switching tube SC2 and the cathode of the diode VD8, and the source electrode of the switching tube SC3 is respectively connected with the drain electrode of the switching tube SC4 and the anode of the diode VD 10. The cathode of the diode VD8 is connected with the anode of the series battery, and the anode of the diode VD10 is connected with the cathode of the series battery.
As shown in fig. 4, the equalizing unit includes a switching tube SH, a switching tube SL, a switch SE, and an inductor L3, where a drain of the switching tube SH is connected to an output anode of the second rectifying circuit, a source of the switching tube SL is connected to an output cathode of the second rectifying circuit, the source of the switching tube SH is respectively connected to the drain of the switching tube SL, one end of the switching tube SE, one end of the inductor L3, the other end of the switching tube SE, and the other end of the inductor L3 are both connected to a terminal PM on one side of a switching array, and the switching array includes N-1 switches S1, S2, and S3 N - 1 One end of any switch is connected with the terminal PM, and the other end of the switch S1, the other end of the switch S2 and the other end of the switch S3 N-1 The other end is respectively connected with a battery B1 negative electrode, a battery B2 negative electrode and a battery B3 negative electrode. The positive electrode of the battery B1 is connected with the output positive electrode of the second rectifying circuit through a switch Sup, and the negative electrode of the battery BN is connected with the output negative electrode of the second rectifying circuit through a switch SDown.
A charging control method of a wireless charging circuit of an electric automobile comprises the following steps:
step one: the power frequency power supply AC obtains direct current containing harmonic waves through a first rectifying circuit;
step two: removing clutter of the direct current obtained in the first step through an LC filter circuit to obtain stable direct current;
step three: the stable direct current obtained in the second step generates high-frequency alternating current on a transmitting coil L1 through an inverter circuit;
step four: the receiving coil L2 generates high-frequency alternating current at two ends through magnetic coupling;
step five: the high-frequency alternating current obtained in the fourth step is converted into direct current containing harmonic waves through a second rectifying circuit at the load side;
step six: the direct current containing harmonic waves obtained in the fifth step is filtered through a variable capacitor to obtain stable direct current;
step seven: the stable direct current obtained in the step six charges the series battery pack through the positive electrode and the negative electrode of the series battery pack;
step eight: the energy difference of each battery unit in the series battery pack is balanced through the balancing unit and the switch array.
A variable capacitance control method controls a switching tube SC1 and a switching tube SC4 to be conducted, a capacitor C2 is connected into a receiving circuit, at the moment, the capacitance value in the circuit is C2, then the switching tube SC4 is controlled to be turned off, a switching tube SC3 is conducted, the capacitor C2 is bypassed from the receiving circuit, and at the moment, the capacitance value of the receiving side is 0. Similarly, the switching tube SC2 and the switching tube SC3 are controlled to be turned on, the capacitor C2 is reversely connected to the receiving circuit, the capacitor value in the circuit is C2, then the switching tube SC3 is controlled to be turned off, the switching tube SC4 is controlled to be turned on, the capacitor C2 is bypassed from the receiving circuit, and the capacitor value at the receiving side is changed to 0.
The time of the capacitor C2 connected to the load side can be controlled by controlling the on time of the switching tube SC1, the switching tube SC2, the switching tube SC3 and the switching tube SC4, that is, the duty ratio of the switching tube, and the equivalent capacitance value is related to the duty ratio for the receiving circuit, and the equivalent capacitance value can be adjusted from 0 to the rated capacitance value thereof, that is, the capacitance value is variable by adjusting the duty ratio of the switching tube.
A battery equalization control method, comprising:
(1) And energy balance between two parts of batteries in the battery pack:
firstly, if the energy of the first i batteries in the battery pack is higher, the redundant energy of the first i batteries in the battery pack needs to be transferred to the last N-i+1 batteries in the battery pack, and the switch Si needs to be closed.
As shown in fig. 7 (a), state one: the control switch SH is turned on, the switch SL is turned off, the front i batteries, the switch SH and the inductor L3 form a discharge loop, the inductor L3 stores energy released by the front i batteries, and the current direction on the inductor is rightward.
As shown in fig. 7 (b), state two: the switching tube SH is controlled to be turned off, the switching tube SL is turned off, and the N-i+1 batteries in the battery pack, the anti-parallel diode of the switching tube SL and the inductor L3 form a discharging loop. The anti-parallel diode of the switching tube SL plays a freewheel role. The inductor L3 releases the energy absorbed in the first stage, the current on the inductor L3 is directed to the right, and the rear N-i+1 cells in the battery pack are charged.
Through the two processes of the state one and the state two, the surplus energy of the first i batteries in the battery pack is stored through the inductor, and then is released to the last N-i+1 batteries in the battery pack through the inductor L3.
(2) The energy of a certain battery in the battery pack is high and needs to be transferred:
when the energy of one cell in the battery pack is high, the energy of the cell needs to be transferred to the rest cells in the battery pack.
Let the difference between Bi and average energy of battery beFirstly, closing a switch Si-1 and opening the switch Si;
as shown in fig. 8 (a), in the state (1), the switching tube SL is turned on, and the batteries Bi to Bn each release energy as Δε 1 This part of the energy is stored in the inductance L3;
as shown in fig. 8 (B), in state (2), the switching tube SL (i-1) is turned off, and the inductor releases the energy stored by the inductor L3 to the battery B1 to the battery Bn-1 in state one;
then closing the switch Si and opening the switch Si-1;
as shown in fig. 8 (c), in the state (3), the switching tube SH is turned on, and the battery B1 to the battery Bi release energy per battery is Δε 2 This part of the energy is temporarily stored in the inductance L3;
as shown in fig. 8 (d), in the state (4), the switching tube SH is turned off, and the inductor L3 releases the energy stored in the state three to the batteries bi+1 to Bn.
By the volt-second balance characteristic of the inductor, the equation pair delta epsilon is written 1 ，△ε 2 And (3) carrying out solving:
equation (1) is the energy variation of the previous i-1 batteries,
equation (2) is the amount of energy change of the ith battery,
equation (3) is the energy variation of the following n-i+1 cells:
simultaneous equation solving:
the control of the four switching tubes can realize that the energy with higher power saving capacity in any battery pack can be evenly distributed to other batteries in the battery pack; when the abnormal battery position is the first position and the last position of the series battery pack, the function can be realized by controlling only one switching tube.
In the charging process, if the battery with lower energy in the battery pack needs to be charged, the first three batteries in the battery pack are set to have lower electric quantity, and the first three batteries need to be additionally charged, and at the moment, the inductor L3 is used as a secondary coil for wireless charging to absorb the energy emitted by a power supply side circuit. Switches Sup and Sdown are closed, switch S3 is closed, and switch SH is closed. At this time, the batteries B1, B2, B3, the switching tube SH, and the inductance L3 constitute a closed loop.
The inductor L3 acts as a secondary coil to absorb energy provided by the transmit circuit. Since high-frequency alternating current is generated on the inductor, a loop is formed by the inductor L3 and the batteries B1, B2 and B3 when the current flows to the left;
when the current of the inductor L3 is directed to the right, a charging loop is formed by the diode and the rest N-3 batteries. Since the inductance L3 absorbs equal energy in the positive and negative cycles, the total energy absorbed by the first three cells is equal to the energy absorbed by the last N-3 cells throughout the cycle. For the single battery, the energy absorbed by each of the first three batteries is larger than the energy absorbed by each of the last N-3 batteries, so that the energy difference of the single battery is reduced, and the additional charge of the battery with lower energy in the battery pack is realized.
Similarly, the equalization circuit can additionally charge any previous battery in the battery pack in the wireless charging process. Similarly, any of the cells after the battery pack may be additionally charged to reduce the energy difference of the unit cells.
FIG. 11 is a flowchart illustrating the operation of the present invention. First, whether or not wireless charging is necessary is determined by determining the total energy of the battery pack, and if necessary, further, whether or not the battery is balanced is determined, and if necessary, wireless charging accompanied by balance control is performed, and if not, wireless charging is performed. If the battery pack has sufficient energy and does not need to be charged wirelessly, but the energy difference of the single batteries is large, and energy balance is needed, the balance battery can be independently controlled to transfer and secondarily distribute the energy of the battery pack, so that the purpose of balance is realized.

Claims (8)

1. An electric automobile wireless charging device with battery energy balance function, which is characterized by comprising: a power supply side circuit, a receiving circuit, and an equalizing circuit;
the power supply side circuit comprises a first rectifying circuit, an LC filter circuit and an inverter circuit, wherein the power frequency power supply AC is connected with the first rectifying circuit, the first rectifying circuit is connected with the LC filter circuit, the LC filter circuit is connected with the inverter circuit, and the inverter circuit is connected with the transmitting coil L1;
the receiving circuit comprises a second rectifying circuit, a variable capacitor and a series battery pack, wherein the receiving coil L2 is connected with the second rectifying circuit, the second rectifying circuit is connected with the variable capacitor, and the variable capacitor is connected with the series battery pack;
the equalization circuit comprises an equalization unit and a switch array, wherein the equalization unit is connected with the switch array, and the switch array is connected with the series battery pack; the energy difference of each battery unit in the series battery pack is balanced through the balancing unit and the switch array;
the equalization unit comprises a switching tube SH, a switching tube SL, a switch SE and an inductor L3, wherein the drain electrode of the switching tube SH is connected with the output anode of the second rectifying circuit, the source electrode of the switching tube SL is connected with the output cathode of the second rectifying circuit, the source electrode of the switching tube SH is respectively connected with the drain electrode of the switching tube SL, one end of the switch SE and one end of the inductor L3, and the other end of the switch SE and the other end of the inductor L3 are respectively connected with one side terminal PM of the switch array;
the switch array comprises N-1 switches S1, S2 and S3, wherein one end of any switch is connected with a terminal PM, the other end of the switch S1, the other end of the switch S2 and the other end of the switch S3 are respectively connected with a battery B1 negative electrode, a battery B2 negative electrode and a battery B3 negative electrode;
in the charging process, if the batteries with lower energy in the battery pack are required to be charged, the front X batteries in the battery pack are required to be additionally charged if the electric quantity of the front X batteries in the battery pack is lower, at the moment, the inductor L3 is used as a secondary coil for wireless charging to absorb the energy emitted by a power supply side circuit, the switches Sup and SDown are closed, the switch SX is closed, and the switch SH is closed; at this time, batteries B1, B2, B3 were charged, the switching tube SH and the inductor L3 form a closed loop;
the inductor L3 is used as a secondary coil to absorb energy provided by the transmitting circuit, and because high-frequency alternating current is generated on the inductor, a loop is formed between the inductor L3 and batteries B1, B2 and B3 and between the inductor L3 and the batteries B1, B2 and B3;
when the current direction of the inductor L3 is rightward, a charging loop is formed by the diode and the rest N-X batteries; because the energy absorbed by the inductor L3 in positive and negative periods is equal, the total energy absorbed by the front X batteries is equal to the energy absorbed by the rear N-X batteries in the whole period;
the equalization circuit can carry out additional charge on any battery before in the battery pack in the wireless charging process, and can also carry out additional charge on any battery after the battery pack.
2. The electric vehicle wireless charging device with a battery energy equalization function according to claim 1, wherein: the first rectifying circuit comprises diodes VD1, VD2, VD3 and VD4; the LC filter circuit comprises an inductor Lf and a capacitor C1; the inverter circuit comprises switching tubes VT1, VT2, VT3 and VT4;
one side of the power frequency power supply AC is respectively connected with the anode of the diode VD1 and the cathode of the diode VD3, and the other side of the power frequency power supply AC is respectively connected with the anode of the diode VD2 and the cathode of the diode VD4; the cathode of the diode VD1 and the cathode of the diode VD2 are both connected with one end of an inductor Lf, the other end of the inductor Lf is connected with one end of a capacitor C1, and the other end of the capacitor C1 is respectively connected with the anode of the diode VD3 and the anode of the diode VD4;
one end of the capacitor C1 is respectively connected with the source electrode of the switch tube VT1 and the source electrode of the switch tube VT2, the other end of the capacitor C1 is respectively connected with the drain electrode of the switch tube VT3 and the drain electrode of the switch tube VT4, the drain electrode of the switch tube VT1 is connected with the source electrode of the switch tube VT3, the drain electrode of the switch tube VT2 is connected with the source electrode of the switch tube VT4, the drain electrode of the switch tube VT1 is connected with one end of the transmitting coil L1, and the other end of the transmitting coil L1 is connected with the source electrode of the switch tube VT4.
3. The electric vehicle wireless charging device with a battery energy equalization function according to claim 1, wherein: the second rectifying circuit comprises a diode VD7, a diode VD8, a diode VD9 and a diode VD10, the variable capacitor comprises a capacitor C2, and the switching tubes SC1, SC2, SC3 and SC4 are connected in series, and the series battery pack comprises n batteries B1, B2 and B3 which are connected in series;
one end of the receiving coil L2 is respectively connected with the anode of the diode VD7 and the cathode of the diode VD9, and the other end of the receiving coil L2 is respectively connected with the anode of the diode VD8 and the cathode of the diode VD 10;
one end of a capacitor C2 is respectively connected with the drain electrode of the switching tube SC1 and the drain electrode of the switching tube SC3, the other end of the capacitor C2 is respectively connected with the source electrode of the switching tube SC2 and the source electrode of the switching tube SC4, the source electrode of the switching tube SC1 is respectively connected with the drain electrode of the switching tube SC2 and the cathode of the diode VD8, and the source electrode of the switching tube SC3 is respectively connected with the drain electrode of the switching tube SC4 and the anode of the diode VD 10;
the cathode of the diode VD8 is connected with the anode of the series battery, and the anode of the diode VD10 is connected with the cathode of the series battery.
4. The electric vehicle wireless charging device with a battery energy equalization function according to claim 1, wherein: the positive electrode of the battery B1 is connected with the output positive electrode of the second rectifying circuit through a switch Sup, and the negative electrode of the battery BN is connected with the output negative electrode of the second rectifying circuit through a switch SDown.
5. A charge control method of an electric vehicle wireless charging circuit employing the electric vehicle wireless charging device according to any one of claims 1 to 4, characterized by comprising the steps of:
step one: the power frequency power supply AC obtains direct current containing harmonic waves through a first rectifying circuit;
step two: removing clutter of the direct current obtained in the first step through an LC filter circuit to obtain stable direct current;
step three: the stable direct current obtained in the second step generates high-frequency alternating current on a transmitting coil L1 through an inverter circuit;
step four: the receiving coil L2 generates high-frequency alternating current at two ends through magnetic coupling;
step five: the high-frequency alternating current obtained in the fourth step is converted into direct current containing harmonic waves through a second rectifying circuit at the load side;
step six: the direct current containing harmonic waves obtained in the fifth step is filtered through a variable capacitor to obtain stable direct current;
step seven: the stable direct current obtained in the step six charges the series battery pack through the positive electrode and the negative electrode of the series battery pack;
step eight: the energy difference of each battery unit in the series battery pack is balanced through the balancing unit and the switch array.
6. A variable capacitance control method using the wireless charging device for electric vehicles according to any one of claims 1 to 4, characterized in that: the switching tube SC1 and the switching tube SC4 are controlled to be conducted, the capacitor C2 is connected to the receiving circuit, the capacitance value in the circuit is C2 at the moment, then the switching tube SC4 is controlled to be turned off, the switching tube SC3 is controlled to be conducted, the capacitor C2 is bypassed from the receiving circuit, and the capacitance value at the receiving side is 0 at the moment;
similarly, the switching tube SC2 and the switching tube SC3 are controlled to be conducted, the capacitor C2 is reversely connected to the receiving circuit, the capacitance value in the circuit is C2 at the moment, then the switching tube SC3 is controlled to be turned off, the switching tube SC4 is controlled to be conducted, the capacitor C2 is bypassed from the receiving circuit, and the capacitance value of the receiving side is changed to 0 at the moment;
the time of the capacitor C2 connected to the load side can be controlled by controlling the on time of the switching tube SC1, the switching tube SC2, the switching tube SC3, and the switching tube SC4, that is, the duty ratio of the switching tube, and the equivalent capacitance value is related to the duty ratio for the receiving circuit, and the equivalent capacitance value can be adjusted from 0 to its rated capacitance value by adjusting the duty ratio of the switching tube.
7. A battery equalization control method using the wireless charging device for electric vehicles according to any one of claims 1 to 4, characterized by comprising:
(1) And energy balance between two parts of batteries in the battery pack:
firstly, setting the energy of the front i batteries in the battery pack to be higher, transferring the redundant energy of the front i batteries in the battery pack to the rear N-i+1 batteries in the battery pack, and closing a switch Si;
state one: the switching tube SH is controlled to be conducted, the switching tube SL is controlled to be turned off, the front i batteries, the switching tube SH and the inductor L3 form a discharging loop, the inductor L3 stores energy released by the front i batteries, and the current direction on the inductor is rightward;
state two: the switching tube SH is controlled to be turned off, the switching tube SL is turned off, and a discharging loop is formed by the N-i+1 batteries in the battery pack, an anti-parallel diode of the switching tube SL and an inductor L3; the anti-parallel diode of the switching tube SL plays a role of follow current; the inductor L3 releases the energy absorbed in the first stage, the current direction on the inductor L3 is rightward, and the rear N-i+1 batteries in the battery pack are charged;
through the two processes of the state one and the state two, the surplus energy of the first i batteries in the battery pack is stored through an inductor, and then released to the last N-i+1 batteries in the battery pack through an inductor L3;
(2) The energy of a certain battery in the battery pack is high and needs to be transferred:
when the energy of one battery in the battery pack is high, the energy of the battery pack needs to be transferred to other batteries in the battery pack;
let the difference between Bi and average energy of battery be
Firstly, closing a switch Si-1 and opening the switch Si;
in the state (1), the switching tube SL is turned on, and the energy released from each of the batteries Bi to Bn is Deltaε 1 This part of the energy is stored in the inductance L3;
in state (2), switching off the switching tube SL (i-1), the inductor releasing the energy stored by the inductor L3 in state one to the battery B1 to the battery Bn-1;
then closing the switch Si and opening the switch Si-1;
in the state (3), the switching tube SH is turned on, and the energy released from each of the batteries B1 to Bi is Deltaε 2 This part of the energy is temporarily stored in the inductance L3;
in state (4), the switching tube SH is turned off, and the inductor L3 releases the energy stored in state three to the batteries bi+1 to Bn.
8. The battery equalization control method of claim 7, wherein:
by the volt-second balance characteristic of the inductor, the equation pair delta epsilon is written 1 ，△ε 2 And (3) carrying out solving:
equation (1) is the energy variation of the previous i-1 batteries,
equation (2) is the amount of energy change of the ith battery,
equation (3) is the energy variation of the following n-i+1 cells:
simultaneous equation solving:
CN202111301907.8A 2021-11-04 2021-11-04 Electric automobile wireless charging device with battery energy balance function and control method thereof Active CN114221452B (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109256844A (en) * 2018-11-01 2019-01-22 三峡大学 A kind of electric car wireless charging circuit and charge control method
CN110323803A (en) * 2019-06-21 2019-10-11 三峡大学 A kind of multiphase interleaved converter suitable for cascaded lithium ion batteries group
WO2021057658A1 (en) * 2019-09-26 2021-04-01 The University Of Hong Kong A wireless battery charging system and method for battery charging and handshaking
CN113131540A (en) * 2019-12-30 2021-07-16 上海北京大学微电子研究院 Battery active equalization circuit based on magnetic resonance wireless power transmission technology and control system thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109256844A (en) * 2018-11-01 2019-01-22 三峡大学 A kind of electric car wireless charging circuit and charge control method
CN110323803A (en) * 2019-06-21 2019-10-11 三峡大学 A kind of multiphase interleaved converter suitable for cascaded lithium ion batteries group
WO2021057658A1 (en) * 2019-09-26 2021-04-01 The University Of Hong Kong A wireless battery charging system and method for battery charging and handshaking
CN113131540A (en) * 2019-12-30 2021-07-16 上海北京大学微电子研究院 Battery active equalization circuit based on magnetic resonance wireless power transmission technology and control system thereof

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