Multi-coil battery pack equalization circuit system

Abstract

The utility model discloses a multi-coil battery pack equalization circuit system, which comprises a plurality of battery pack coil modules, a relay multi-coil loop, an acquisition and comparison module and a digital signal processing module, each battery pack coil module is coupled with the relay multi-coil loop; the acquisition and comparison module is respectively connected with the battery pack coil module and the digital signal processing module; the digital signal processing module is in communication connection with each battery pack coil module; the technical problem that an existing equalization circuit system is low in integration level is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of wireless power transmission, in particular to a multi-coil battery pack balancing circuit system. Background Art

[0002] The booming development of electric vehicles has boosted the demand for lithium-ion batteries. However, due to the differences in initial capacity, internal resistance and self-discharge rate of each lithium battery cell in a lithium battery pack, the battery capacity difference between each lithium battery cell will increase with the use of the lithium battery pack, resulting in widespread inconsistency between lithium battery cells.

[0003] As an important part of the battery management system (BMS), balancing technology can reduce or even eliminate the above inconsistency by actively balancing the battery pack through the balancing function of the battery management system. Balancing is to use electronic technology to keep the voltage deviation of the battery cells within the expected range, so as to ensure that each single cell is not damaged during normal use. If balancing control is not performed, as the charge and discharge cycles increase, the voltage of each single cell will gradually diverge, and the service life will be greatly reduced.

[0004] In the existing balancing circuit system, a shunt resistor needs to be connected in parallel outside each battery. The energy of the battery cell with high remaining capacity is consumed through the resistor by controlling the corresponding switching device, and cables are required to connect the various battery cells, resulting in low integration of the balancing circuit system. Utility Model Content

[0005] In order to solve the technical problem of low integration of the existing equalizing circuit system, the utility model discloses a multi-coil battery pack equalizing circuit system.

[0006] The utility model provides a multi-coil battery pack equalization circuit system, the system comprises a plurality of battery pack coil modules, a relay multi-coil loop, a collection and comparison module and a digital signal processing module;

[0007] Each of the battery pack coil modules is coupled to the relay multi-coil loop;

[0008] The acquisition and comparison module is connected to the battery pack coil module and the digital signal processing module respectively;

[0009] The digital signal processing module is respectively connected to each of the battery pack coil modules for communication.

[0010] Optionally, the relay multi-coil loop includes a cascaded relay coil compensation capacitor and a plurality of relay coils;

[0011] The plurality of battery pack coil modules are coupled and connected with the plurality of relay coils in a one-to-one correspondence.

[0012] Optionally, the battery pack coil module includes a capacitor coil submodule and a battery pack, a DC filter capacitor, and an H-bridge conversion circuit inductor and capacitor module connected in parallel in sequence;

[0013] One end of the capacitor coil submodule is connected to the H-bridge conversion circuit inductor and capacitor module, and the other end of the capacitor coil submodule is coupled and connected to the relay coil;

[0014] The battery pack and the H-bridge conversion circuit inductor and capacitor module are both connected to the acquisition and comparison module, and the H-bridge conversion circuit inductor and capacitor module is communicatively connected to the digital signal processing module.

[0015] Optionally, the H-bridge conversion circuit inductor and capacitor module includes an H-bridge conversion circuit, a parallel resonant inductor and a parallel resonant capacitor;

[0016] The H-bridge conversion circuit includes two sets of switch tube modules connected in parallel, and the switch tube module includes two switch tubes connected in series;

[0017] The switch tube is communicatively connected with the digital signal processing module;

[0018] The DC filter capacitor is connected in parallel with the switch tube module;

[0019] One end of the parallel resonant inductor is connected between two switch tubes in a group of the switch tube modules, and the other end of the parallel resonant inductor is respectively connected to one end of the parallel resonant capacitor and one end of the capacitor coil submodule;

[0020] The other end of the parallel resonant capacitor is connected between two switch tubes in another group of the switch tube modules, and is connected to one end of the capacitor coil submodule;

[0021] The acquisition and comparison module is connected to the other end of the parallel resonant capacitor.

[0022] Optionally, the capacitor coil submodule includes a primary coupling coil compensation capacitor and a primary coupling coil;

[0023] One end of the primary coupling coil compensation capacitor is respectively connected to the other end of the parallel resonant inductor and one end of the parallel resonant capacitor;

[0024] The other end of the primary coupling coil compensation capacitor is connected to the first end of the primary coupling coil, and the second end of the primary coupling coil is connected to the other end of the parallel resonant capacitor;

[0025] The third end of the primary coupling coil is coupled to the relay coil.

[0026] Optionally, the switch tube includes a parasitic diode and a field effect tube;

[0027] The cathode of the parasitic diode is connected to the drain of the field effect transistor, and the anode of the parasitic diode is connected to the source of the field effect transistor;

[0028] The gate of the field effect tube is communicatively connected to the digital signal processing module.

[0029] Optionally, the acquisition and comparison module includes a voltage and current detection circuit and a current zero-crossing detection circuit;

[0030] The battery pack is connected to one end of the voltage and current detection circuit, and the other end of the voltage and current detection circuit is connected to the digital signal processing module;

[0031] The other end of the parallel resonant capacitor is connected to one end of the current zero-crossing detection circuit, and the other end of the current zero-crossing detection circuit is connected to the digital signal processing module.

[0032] Optionally, the voltage and current detection circuit includes a voltage measurement circuit and a current measurement circuit;

[0033] One end of the voltage measurement circuit is connected to the positive electrode of the battery pack, and the other end of the voltage measurement circuit is connected to the digital signal processing module;

[0034] One end of the current measurement circuit is connected to the negative electrode of the battery pack, and the other end of the current measurement circuit is connected to the digital signal processing module.

[0035] Optionally, the voltage measurement circuit includes a first voltage resistor, a second voltage resistor, a third voltage resistor, a fourth voltage resistor, a fifth voltage resistor, a sixth voltage resistor, a seventh voltage resistor, a first voltage capacitor, a second voltage capacitor, a third voltage capacitor, a fourth voltage capacitor, a first voltage operational amplifier, a second voltage operational amplifier, a first voltage diode, and a second voltage diode;

[0036] One end of the first voltage resistor is connected to the positive electrode of the battery pack, and the other end of the first voltage resistor is connected to one end of the second voltage resistor;

[0037] One end of the first voltage capacitor is connected to the non-inverting input end of the first voltage operational amplifier, and the other end of the second voltage resistor is connected to the other end of the first voltage capacitor and the negative electrode of the battery pack respectively;

[0038] One end of the third voltage resistor is connected to the inverting input end of the first voltage operational amplifier, and the other end of the third voltage resistor is connected to one end of the fourth voltage resistor and the output end of the first voltage operational amplifier respectively;

[0039] The other end of the fourth voltage resistor is connected to one end of the fifth voltage resistor and one end of the second voltage capacitor respectively;

[0040] One end of the third voltage capacitor is grounded, and the other end of the fifth voltage resistor is connected to the non-inverting input end of the second voltage operational amplifier and the other end of the third voltage capacitor respectively;

[0041] The other end of the second voltage capacitor is connected to the inverting input end of the second voltage operational amplifier, and the output end of the second voltage operational amplifier is connected to the other end of the second voltage capacitor and one end of the sixth voltage resistor respectively;

[0042] The other end of the sixth voltage resistor is respectively connected to one end of the fourth voltage capacitor, one end of the seventh voltage resistor, the cathode of the first voltage diode, and the anode of the second voltage diode;

[0043] The other end of the fourth voltage capacitor, the other end of the seventh voltage resistor, and the anode of the first voltage diode are all grounded, and the cathode of the second voltage diode is externally connected to a 3.3V voltage port;

[0044] The common ends of the anode of the first voltage diode and the cathode of the second voltage diode are both connected to the digital signal processing module.

[0045] Optionally, the current measurement circuit includes a current sensor, a current operational amplifier, a first current resistor, a second current resistor, a third current resistor, a first current capacitor, a second current capacitor, a first current diode and a second current diode;

[0046] The positive power port of the current sensor is connected to one end of the DC filter capacitor, and the negative power port of the current sensor is connected to the negative electrode of the battery pack;

[0047] The output port of the current sensor is connected to the non-inverting input terminal of the current operational amplifier, and the non-inverting input terminal of the current operational amplifier is connected to one end of the first current resistor;

[0048] The output end of the current operational amplifier is respectively connected to the other end of the first current resistor, one end of the second current resistor, and one end of the first current capacitor;

[0049] The other end of the second current resistor is respectively connected to the other end of the first current capacitor, one end of the third current resistor, one end of the second current capacitor, the cathode of the first current diode, and the anode of the second current diode;

[0050] The other end of the third current resistor, the other end of the second current capacitor, and the anode of the first current diode are all grounded, and the cathodes of the second current diodes are externally connected to a 3.3V voltage port;

[0051] A common end of the cathode of the first current diode and an anode of the second current diode are both connected to the digital signal processing module.

[0052] It can be seen from the above technical solutions that the utility model has the following advantages:

[0053] The utility model provides a multi-coil battery pack balancing circuit system, which includes multiple battery pack coil modules, a relay multi-coil loop, an acquisition and comparison module and a digital signal processing module; each battery pack coil module is coupled and connected with the relay multi-coil loop; the acquisition and comparison module is respectively connected with the battery pack coil module and the digital signal processing module; the digital signal processing module is respectively communicatively connected with each battery pack coil module; based on the above scheme, each battery pack coil module is coupled and connected with the relay multi-coil loop, compared with the circuit system design in the existing balancing circuit system that requires cables to connect each battery unit, it can reduce the connection lines between the battery pack and the circuit, and further improve the integration of the balancing circuit system. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0055] Figure 1 It is a structural schematic diagram of a multi-coil battery pack balancing circuit system provided in an embodiment of the utility model;

[0056] Figure 2 A control principle diagram of a multi-coil battery pack balancing circuit system provided in an embodiment of the utility model;

[0057] Figure 3 A schematic diagram of a half-bridge active rectification working mode of a multi-coil battery pack balancing circuit system provided in an embodiment of the utility model;

[0058] Figure 4A switching synchronization waveform diagram under the control of an AC equivalent load provided in an embodiment of the utility model;

[0059] Figure 5 It is a schematic diagram of comparing the transmission efficiency of the front and rear multi-coil battery pack balancing circuit system under the same conditions provided in the embodiment of the utility model;

[0060] Figure 6 It is a schematic diagram of the structure of the voltage detection circuit provided in the embodiment of the utility model;

[0061] Figure 7 It is a structural schematic diagram of the current detection circuit provided in the embodiment of the utility model.

[0062] The meanings of the symbols in the accompanying drawings are as follows:

[0063] 1. Battery pack coil transmitting submodule; 2. Battery pack coil receiving submodule; 3. Battery pack coil submodule; 4. Relay multi-coil loop; 5. Voltage and current detection circuit; 6. Current zero-crossing detection circuit; 7. Digital signal processing module; 8. H-bridge conversion circuit. DETAILED DESCRIPTION

[0064] The utility model discloses a multi-coil battery pack equalizing circuit system, which is used to solve the technical problem of low integration of the existing equalizing circuit system.

[0065] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0066] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0067] Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0068] See also Figure 1 , Figure 1 It is a structural schematic diagram of a multi-coil battery pack balancing circuit system provided in an embodiment of the utility model.

[0069] An embodiment of the utility model provides a multi-coil battery pack balancing circuit system, which includes multiple battery pack coil modules, a relay multi-coil loop 4, an acquisition and comparison module and a digital signal processing module 7; each battery pack coil module is coupled and connected to the relay multi-coil loop 4; the acquisition and comparison module is respectively connected to the battery pack coil module and the digital signal processing module 7; the digital signal processing module 7 is respectively communicated with each battery pack coil module.

[0070] Optionally, the relay multi-coil loop 4 includes a cascaded relay coil compensation capacitor and a plurality of relay coils;

[0071] The multiple battery pack coil modules are coupled and connected with the multiple relay coils in a one-to-one correspondence.

[0072] Please note that Figure 1 , multiple battery coil modules include at least one battery coil transmitting submodule 1, at least one battery coil receiving submodule 2 and multiple battery coil submodules 3. Among all the battery coil modules, the battery coil module with the highest battery voltage is used as the battery coil transmitting submodule 1, and the battery coil module with the lowest battery voltage is used as the battery coil receiving submodule 2. The battery coil transmitting submodule 1, the battery coil receiving submodule 2 and each battery coil submodule 3 are all electrically connected to an acquisition and comparison module. After determining the battery coil transmitting submodule 1 and the battery coil receiving submodule 2, the acquisition and comparison module connected to the battery coil receiving submodule 2 allows it to work.

[0073] Furthermore, the battery pack coil transmitting submodule 1, the battery pack coil receiving submodule 2 and each battery pack coil submodule 3 are respectively coaxially arranged with any relay coil in the relay multi-coil loop 4, and the battery pack coil transmitting submodule 1, the battery pack coil receiving submodule 2 and the battery pack coil submodule 3 have the same symmetrical topological structure; among which, the battery pack coil transmitting submodule 1 is the battery pack coil module with the highest voltage, and the battery pack coil receiving submodule 2 is the battery pack coil module with the lowest voltage.

[0074] Furthermore, the relay multi-coil loop 4 is composed of a relay coil compensation capacitor and multiple relay coils connected in series, and each relay coil is coupled and connected with the battery pack coil transmitting submodule 1, the battery pack coil receiving submodule 2 and each battery pack coil submodule 3 in a one-to-one correspondence, that is, the battery pack coil transmitting submodule 1, the battery pack coil receiving submodule 2, and each battery pack coil submodule 3 are coupled and connected with a relay coil.

[0075] In a preferred embodiment, the battery pack coil module includes a capacitor coil submodule and a battery pack, a DC filter capacitor, and an H-bridge conversion circuit inductor and capacitor module connected in parallel in sequence;

[0076] One end of the capacitor coil submodule is connected to the inductor capacitor module of the H-bridge conversion circuit, and the other end of the capacitor coil submodule is coupled and connected to the relay coil;

[0077] The battery pack and the H-bridge conversion circuit inductor and capacitor module are both connected to the acquisition and comparison module, and the H-bridge conversion circuit inductor and capacitor module is communicatively connected to the digital signal processing module 7 .

[0078] Optionally, the inductor and capacitor module of the H-bridge conversion circuit includes an H-bridge conversion circuit 8, a parallel resonant inductor and a parallel resonant capacitor; the H-bridge conversion circuit 8 includes two groups of parallel switch tube modules, and the switch tube module includes two switch tubes connected in series; the switch tube is communicatively connected to the digital signal processing module 7; the DC filter capacitor is connected in parallel to the switch tube module; one end of the parallel resonant inductor is connected between two switch tubes in one group of switch tube modules, and the other end of the parallel resonant inductor is respectively connected to one end of the parallel resonant capacitor and one end of the capacitor coil sub-module; the other end of the parallel resonant capacitor is connected between two switch tubes in another group of switch tube modules, and is connected to one end of the capacitor coil sub-module; the acquisition and comparison module is connected to the other end of the parallel resonant capacitor.

[0079] Optionally, the capacitor coil submodule includes a primary coupling coil compensation capacitor and a primary coupling coil; one end of the primary coupling coil compensation capacitor is respectively connected to the other end of the parallel resonant inductor and one end of the parallel resonant capacitor; the other end of the primary coupling coil compensation capacitor is connected to the first end of the primary coupling coil, and the second end of the primary coupling coil is connected to the other end of the parallel resonant capacitor; the third end of the primary coupling coil is coupled to the relay coil.

[0080] It should be noted that the battery pack coil transmitting submodule 1, the battery pack coil receiving submodule 2 and the battery pack coil submodule 3 are all composed of a capacitor coil submodule and a battery pack, a DC filter capacitor, and an H-bridge conversion circuit inductor and capacitor module connected in parallel in sequence, wherein the H-bridge conversion circuit inductor and capacitor module is composed of an H-bridge conversion circuit 8, a parallel resonant inductor and a parallel resonant capacitor, and the H-bridge conversion circuit 8 is composed of four switching tubes, each bridge arm includes two switching tubes, the upper tube source is connected to the lower tube drain, and the switch tube is communicatively connected to the digital signal processing module 7.

[0081] In a preferred embodiment, the acquisition and comparison module includes a voltage and current detection circuit 5 and a current zero-crossing detection circuit 6; the battery pack is connected to one end of the voltage and current detection circuit 5, and the other end of the voltage and current detection circuit 5 is connected to a digital signal processing module 7 (digital signal processing, digital signal processor); the other end of the parallel resonant capacitor is connected to one end of the current zero-crossing detection circuit 6, and the other end of the current zero-crossing detection circuit 6 is connected to the digital signal processing module 7.

[0082] In actual use, please refer to Figure 2 The utility model utilizes coaxial placement of multiple coils to complete the connection between multiple battery pack coil modules and the relay multi-coil loop 4, thereby improving the integration of the balancing circuit system. Next, the voltage of the battery packs in all the battery pack coil modules is collected, and the average voltage value of the battery pack is calculated according to all the voltage values. The battery pack with the highest voltage is controlled as the transmitter, that is, the battery pack coil module with the highest battery pack voltage is used as the battery pack coil transmitting submodule 1, and the battery pack coil module with the lowest battery pack voltage is used as the battery pack coil receiving submodule 2 and connected to the balancing circuit, so that the voltage and current detection circuit 5 and the current zero-crossing detection module connected to the battery pack coil receiving submodule 2 are operated, and the digital signal processing module 7 is controlled to send a complementary conduction signal with a switching frequency of f=85Hz and a duty cycle of D=0.5 to the switch tube in the H-bridge inverter circuit (H-bridge conversion circuit 8) of the battery pack coil transmitting submodule 1. After the circuit is stable, the voltage V of the battery pack coil receiving submodule 2 is collected through the voltage and current measurement module connected to the battery pack coil receiving submodule 2. 02 、Current I 02 The current zero-crossing detection module connected to the battery pack coil receiving submodule 2 continuously generates a square wave phase-locked pulse signal (zero-crossing pulse signal) in phase with the current and transmits it to the digital signal processing module 7. The digital signal processing module 7 uses V 02 ,I 02 Calculate the receiving module power P 02 , the receiving module power and the set rated power After the difference is made, PI adjustment is performed to obtain the adjusted power difference. According to the adjusted power difference and the square wave phase-locked pulse signal, the generated receiving-side rectifier drive signal can control the on and off of the four switch tubes in the H-bridge conversion circuit 8 of the battery pack coil receiving submodule 2, thereby adjusting the transmission efficiency of the entire multi-coil battery pack balancing circuit system to maintain the maximum value, until the voltage value of the battery pack coil receiving submodule 2 is close to the average voltage value of the battery pack obtained by calculation, and then continue to collect the voltage of the battery pack in the remaining battery pack coil modules, re-determine the new battery pack coil transmitting submodule 1 and the battery pack coil receiving submodule 2, and repeat the above process, thereby completing the balancing of all battery pack coil modules, and can achieve the maximum efficiency tracking of energy transmission during the balancing process, solving the technical problem of the continuous decline in efficiency during the balancing process; it should be noted that the description of the above actual use method is only used to illustrate the beneficial effects brought about by the structure of this system, and does not represent the system The protection content involves the above method. After obtaining the system, the technical personnel in this field can use the system reasonably according to their needs. In this embodiment, the technical personnel in this field can collect the voltage of the battery pack in all the battery pack coil modules based on common knowledge, so as to determine the battery pack coil transmitting submodule 1 and the battery pack coil receiving submodule 2. At the same time, the digital signal processing module 7 is used to generate the receiving side rectifier drive signal and control the on and off of the four switch tubes according to the voltage, current and square wave phase-locked pulse signal. This is the method content that the technical personnel in this field can implement based on the prior art. The realization of the above technical effect does not depend on the improvement of the method, but depends on the structure of the hardware and the use of the existing hardware working method. The description of the above actual use method is only used to illustrate the beneficial effects brought by the structure of the present system, and does not mean that the protection content of the present system involves the above method. After obtaining the system, the technical personnel in this field can use the system reasonably according to their needs.

[0083] In this embodiment, four switching tubes constitute an H-bridge conversion circuit 8, each bridge arm includes two switching tubes, and the source of the upper tube is connected to the drain of the lower tube; the battery pack and the DC filter capacitor are connected in parallel with the switch arm as the DC side of the H-bridge conversion circuit 8; one side of the parallel resonant inductor is connected to the midpoint of the first bridge arm of the H-bridge conversion circuit 8, and the other side is connected to the parallel resonant capacitor, and the common point is connected to the primary coupling coil compensation capacitor; one side of the primary coupling coil is connected to the primary coupling coil compensation capacitor, and the other side is connected to the midpoint of the second bridge arm of the H-bridge conversion circuit 8 and the other side of the parallel resonant capacitor.

[0084] As an illustration of the technical effect, the utility model takes three battery coil modules as an example. After determining the battery coil transmitting submodule 1 and the battery coil receiving submodule 2, when the system starts balancing, the circuit equation can be known from Kirchhoff's voltage law as follows:

[0085]

[0086] Among them, U ac (1) is the inverter voltage after the H-bridge conversion circuit of the battery pack coil transmitting submodule is transformed; j is the imaginary unit; ω is the angular frequency; L f1 is the parallel resonant inductance of the first battery pack coil module; I1 is the current of the first primary coupling coil; C f1 is the parallel resonant capacitor of the first battery pack coil module; C1 is the primary coupling coil compensation capacitor of the first battery pack coil module; L 11 is the first primary coupling coil; R is the parasitic resistance of the coupling coil; M is the mutual inductance of the coupling coil; I0 is the relay coil current; L 12 is the first relay coil in the relay multi-coil loop; C0 is the relay coil compensation capacitor; L 22 It is the second relay coil in the relay multi-coil loop; L 32 is the third relay coil in the relay multi-coil loop; I2 is; C2 is the primary coupling coil compensation capacitor of the second battery pack coil module; L 21 is the second primary coupling coil; I f2 The current of the battery pack coil receiving submodule; R load is the equivalent load of the battery coil receiving submodule on the rectifier side; L f2 is the parallel resonant inductance of the second battery pack coil module; C f2 is the parallel resonant capacitor of the second battery pack coil module.

[0087] Based on the above, the current flowing through the battery pack coil receiving submodule 2 can be obtained as:

[0088]

[0089] Among them, I f2 The current of the battery pack coil receiving submodule; L f2 is the parallel resonant inductance of the second battery pack coil module; M is the mutual inductance of the coupled coil; U ac (1) is the inverter voltage after the H-bridge conversion circuit of the battery pack coil transmitting submodule; ω is the angular frequency; L f1 is the parallel resonant inductance of the first battery pack coil module; R is the parasitic resistance of the coupling coil; R load It is the equivalent load of the battery pack coil receiving submodule on the rectifier side.

[0090] Furthermore, combining the above expressions, the efficiency expression can be obtained as follows:

[0091]

[0092] Where, η is the efficiency; L f2is the parallel resonant inductance of the second battery pack coil module; M is the mutual inductance of the coupled coil; ω is the angular frequency; R load is the equivalent load of the battery pack coil receiving submodule on the rectifier side; R is the parasitic resistance of the coupling coil.

[0093] Furthermore, when the system is in steady state, the transmission efficiency of the system is related to the equivalent load resistance of the front side of the full-bridge rectifier, and there is a maximum point. The utility model uses the half-bridge active rectification principle to ensure that the balanced system works under the load condition of maximum efficiency and realizes efficient bidirectional power transmission between batteries. For details, please refer to Figure 3 , in the half-bridge active rectification mode, such as Figure 3 (a) and (c) show that when I o,ac >0 or I o,ac <0, S6 or S8 is open and the output AC voltage is zero. Figure 3 (b) and (d) show that when all switches are off, the S-BAR acts as a typical diode rectifier; therefore, the output AC voltage V can be adjusted by controlling the conduction time of S6 or S8. o,ac1 The fundamental component of the AC equivalent load Z can be controlled o,ac , in the control AC equivalent load Z o,ac The switching synchronization waveform below is as follows Figure 4 As an illustration of the beneficial effects of the system structure, this embodiment also provides a specific control method process of a multi-coil battery pack equalization circuit system for reference by technicians. It should be noted that the improvement of this application lies in the structure of the circuit system, and the following method description is only an example to prove the system effect:

[0094] After completing the connection between multiple battery pack coil modules and the relay multi-coil loop 4, the voltages of the battery packs in all the battery pack coil modules are collected, and the average voltage value of the battery pack is calculated according to all the voltage values, and the battery pack with the highest voltage is controlled as the transmitter, that is, the battery pack coil module with the highest battery pack voltage is used as the battery pack coil transmitting submodule 1, and the battery pack coil module with the lowest battery pack voltage is used as the battery pack coil receiving submodule 2 and connected to the balancing circuit, so that the voltage and current detection circuit 5 and the current zero-crossing detection module connected to the battery pack coil receiving submodule 2 are operated, and the duty cycle and switch conduction point of the battery pack coil transmitting submodule 1 are controlled by the digital signal processing module 7, that is, the complementary conduction signal of the switching frequency and duty cycle is sent to the H-bridge inverter circuit (H-bridge conversion circuit 8) of the battery pack coil transmitting submodule 1 through the digital signal processing module 7. After the circuit is stable, the V of the battery pack coil receiving submodule 2 is collected through the voltage and current measurement module connected to the battery pack coil receiving submodule 2. 02 ,I 02(voltage, current), and transmit the square wave phase-locked pulse signal (zero-crossing pulse signal) which is in phase with the current and is continuously generated by the current zero-crossing detection module connected to the battery pack coil receiving submodule 2 to the digital signal processing module 7, and the digital signal processing module 7 adopts V 02 ,I 02 Calculate the receiving module power P 02 , the receiving module power and the set rated power After the difference is made, PI adjustment is performed to obtain the adjusted power difference. According to the adjusted power difference and the square wave phase-locked pulse signal, the receiving-side rectifier drive signal is generated and the on-off of the switch device is controlled, that is, the receiving-side rectifier drive signal is used to control the on-off of the four switch tubes in the H-bridge conversion circuit 8 of the battery pack coil receiving submodule 2. By controlling the rectifier of the battery pack coil receiving submodule 2, the system works under the optimal load conditions to ensure that the balancing system works under the load conditions with maximum efficiency, thereby realizing efficient two-way power transmission between batteries.

[0095] Furthermore, control design is performed based on the above steps, and simulation experiments are performed using Matlab / Simulink to verify the effectiveness of the utility model. To facilitate understanding, the initial voltage value for balancing the three battery modules is set: U BT1 =51V, U BT2 =48V, U BT3 =49.5V, other simulation parameters are shown in Table 1:

[0096] Table 1 Simulation parameters

[0097]

[0098] For further information, see Figure 5 Based on the Matlab / Simulink simulation results, the system transmission efficiency comparison before and after control under the same conditions is shown; specifically, in the natural equilibrium mode without control, the efficiency is decreasing with the increase of time; in the maximum efficiency tracking mode, as the equilibrium process proceeds, the efficiency has been maintained at around 85.3%, and compared with the uncontrolled mode, the efficiency has been increased by 3%. It can be seen that the maximum efficiency tracking control of the utility model is superior.

[0099] In a preferred embodiment, the switch tube includes a parasitic diode and a field effect tube;

[0100] The cathode of the parasitic diode is connected to the drain of the field effect transistor, and the anode of the parasitic diode is connected to the source of the field effect transistor;

[0101] The gate of the field effect tube is communicatively connected to the digital signal processing module 7 .

[0102] It should be noted that the switching tube is composed of a field effect tube and a parasitic diode.

[0103] In a preferred embodiment, the voltage and current detection circuit 5 includes a voltage measurement circuit and a current measurement circuit;

[0104] One end of the voltage measurement circuit is connected to the positive electrode of the battery pack, and the other end of the voltage measurement circuit is connected to the digital signal processing module 7;

[0105] One end of the current measurement circuit is connected to the negative electrode of the battery pack, and the other end of the current measurement circuit is connected to the digital signal processing module 7 .

[0106] Optionally, the voltage measurement circuit includes a first voltage resistor, a second voltage resistor, a third voltage resistor, a fourth voltage resistor, a fifth voltage resistor, a sixth voltage resistor, a seventh voltage resistor, a first voltage capacitor, a second voltage capacitor, a third voltage capacitor, a fourth voltage capacitor, a first voltage operational amplifier, a second voltage operational amplifier, a first voltage diode, and a second voltage diode;

[0107] One end of the first voltage resistor is connected to the positive electrode of the battery pack, and the other end of the first voltage resistor is connected to one end of the second voltage resistor;

[0108] One end of the first voltage capacitor is connected to the non-inverting input end of the first voltage operational amplifier, and the other end of the second voltage resistor is connected to the other end of the first voltage capacitor and the negative electrode of the battery pack respectively;

[0109] One end of the third voltage resistor is connected to the inverting input end of the first voltage operational amplifier, and the other end of the third voltage resistor is connected to one end of the fourth voltage resistor and the output end of the first voltage operational amplifier respectively;

[0110] The other end of the fourth voltage resistor is connected to one end of the fifth voltage resistor and one end of the second voltage capacitor respectively;

[0111] One end of the third voltage capacitor is grounded, and the other end of the fifth voltage resistor is connected to the non-inverting input end of the second voltage operational amplifier and the other end of the third voltage capacitor respectively;

[0112] The other end of the second voltage capacitor is connected to the inverting input end of the second voltage operational amplifier, and the output end of the second voltage operational amplifier is connected to the other end of the second voltage capacitor and one end of the sixth voltage resistor respectively;

[0113] The other end of the sixth voltage resistor is respectively connected to one end of the fourth voltage capacitor, one end of the seventh voltage resistor, the cathode of the first voltage diode, and the anode of the second voltage diode;

[0114] The other end of the fourth voltage capacitor, the other end of the seventh voltage resistor, and the anode of the first voltage diode are all grounded, and the cathode of the second voltage diode is externally connected to a 3.3V voltage port;

[0115] The common ends of the anode of the first voltage diode and the cathode of the second voltage diode are both connected to the digital signal processing module 7 .

[0116] Please note that Figure 6 The voltage measurement circuit is composed of seven resistors (a first voltage resistor R1, a second voltage resistor R2, a third voltage resistor R3, a fourth voltage resistor R4, a fifth voltage resistor R5, a sixth voltage resistor R8, and a seventh voltage resistor R9), four capacitors (a first voltage capacitor C1, a second voltage capacitor C2, a third voltage capacitor C3, and a fourth voltage capacitor C4), two operational amplifiers (a first voltage operational amplifier and a second voltage operational amplifier), and two diodes (a first voltage diode D1 and a second voltage diode D2), wherein one end of the first voltage resistor is connected to the positive electrode (battery+) of the battery pack, and the other end of the second voltage resistor is respectively connected to the other end of the first voltage capacitor and the negative electrode (battery-) of the battery pack.

[0117] Optionally, the current measurement circuit includes a current sensor, a current operational amplifier, a first current resistor, a second current resistor, a third current resistor, a first current capacitor, a second current capacitor, a first current diode and a second current diode;

[0118] The positive power port of the current sensor is connected to one end of the DC filter capacitor, and the negative power port of the current sensor is connected to the negative electrode of the battery pack;

[0119] The output port of the current sensor is connected to the non-inverting input terminal of the current operational amplifier, and the non-inverting input terminal of the current operational amplifier is connected to one end of the first current resistor;

[0120] The output end of the current operational amplifier is respectively connected to the other end of the first current resistor, one end of the second current resistor, and one end of the first current capacitor;

[0121] The other end of the second current resistor is respectively connected to the other end of the first current capacitor, one end of the third current resistor, one end of the second current capacitor, the cathode of the first current diode, and the anode of the second current diode;

[0122] The other end of the third current resistor, the other end of the second current capacitor, and the anode of the first current diode are all grounded, and the cathode of the second current diode is externally connected to a 3.3V voltage port;

[0123] The common end of the cathode of the first current diode and the anode of the second current diode are both connected to the digital signal processing module 7 .

[0124] Please note that Figure 7 The current measurement circuit consists of a current sensor, an operational amplifier (current operational amplifier), three resistors (a first current resistor R1, a second current resistor R2, and a third current resistor R3), two capacitors (a first current capacitor C1 and a second current capacitor C2), and two diodes (a first current diode D1 and a second current diode D2).

[0125] As a comparison of technical effects, we can refer to the existing technology. In the existing balancing technology, cables are required to connect each battery unit, which has a complex structure and low integration. Although the wireless power transmission (Wireless Power Transfer, WPT) technology has the potential to eliminate the wires directly connected in energy transmission, in the process of wireless power transmission of electric energy, it is affected by load changes and will reduce the efficiency of energy transmission during the transmission process.

[0126] In response to the above problems, the present application proposes a multi-coil battery pack balancing circuit system, which can ensure that the balancing system operates under the load conditions of maximum efficiency and realize efficient two-way power transmission between batteries. It also simplifies the design of the balancing circuit, reduces the connecting wires between the battery and the circuit, and improves the system integration.

[0127] In an embodiment of the present application, the present application provides a multi-coil battery pack balancing circuit system, which includes multiple battery pack coil modules, a relay multi-coil loop, an acquisition and comparison module and a digital signal processing module; each battery pack coil module is coupled and connected to the relay multi-coil loop; the acquisition and comparison module is respectively connected to the battery pack coil module and the digital signal processing module; the digital signal processing module is respectively communicatively connected to each battery pack coil module; based on the above scheme, each battery pack coil module is coupled and connected to the relay multi-coil loop, compared with the existing balancing circuit system design that requires cables to connect each battery cell, it can reduce the connecting lines between the battery pack and the circuit, and further improve the integration of the balancing circuit system.

[0128] The above is a detailed introduction to a multi-coil battery pack balancing circuit system provided by the present invention. For those skilled in the art, according to the idea of ​​the embodiments of the present invention, there may be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A multi-coil battery pack balancing circuit system, characterized in that: The system includes a plurality of battery pack coil modules, a relay multi-coil loop, an acquisition and comparison module, and a digital signal processing module; Each of the battery pack coil modules is coupled to the relay multi-coil loop; The acquisition and comparison module is connected to the battery pack coil module and the digital signal processing module respectively; The digital signal processing module is respectively connected to each of the battery pack coil modules for communication.

2. The multi-coil battery pack balancing circuit system according to claim 1, characterized in that: The relay multi-coil loop includes a cascaded relay coil compensation capacitor and a plurality of relay coils; The plurality of battery pack coil modules are coupled and connected with the plurality of relay coils in a one-to-one correspondence.

3. The multi-coil battery pack balancing circuit system according to claim 2, characterized in that: The battery pack coil module includes a capacitor coil submodule and a battery pack, a DC filter capacitor, and an H-bridge conversion circuit inductor and capacitor module connected in parallel in sequence; One end of the capacitor coil submodule is connected to the H-bridge conversion circuit inductor and capacitor module, and the other end of the capacitor coil submodule is coupled and connected to the relay coil; The battery pack and the H-bridge conversion circuit inductor and capacitor module are both connected to the acquisition and comparison module, and the H-bridge conversion circuit inductor and capacitor module is communicatively connected to the digital signal processing module.

4. The multi-coil battery pack balancing circuit system according to claim 3, characterized in that: The H-bridge conversion circuit inductor and capacitor module includes an H-bridge conversion circuit, a parallel resonant inductor and a parallel resonant capacitor; The H-bridge conversion circuit includes two sets of switch tube modules connected in parallel, and the switch tube module includes two switch tubes connected in series; The switch tube is communicatively connected with the digital signal processing module; The DC filter capacitor is connected in parallel with the switch tube module; One end of the parallel resonant inductor is connected between two switch tubes in a group of the switch tube modules, and the other end of the parallel resonant inductor is respectively connected to one end of the parallel resonant capacitor and one end of the capacitor coil submodule; The other end of the parallel resonant capacitor is connected between two switch tubes in another group of the switch tube modules, and is connected to one end of the capacitor coil submodule; The acquisition and comparison module is connected to the other end of the parallel resonant capacitor.

5. The multi-coil battery pack balancing circuit system according to claim 4, characterized in that: The capacitor coil submodule includes a primary coupling coil compensation capacitor and a primary coupling coil; One end of the primary coupling coil compensation capacitor is respectively connected to the other end of the parallel resonant inductor and one end of the parallel resonant capacitor; The other end of the primary coupling coil compensation capacitor is connected to the first end of the primary coupling coil, and the second end of the primary coupling coil is connected to the other end of the parallel resonant capacitor; The third end of the primary coupling coil is coupled to the relay coil.

6. The multi-coil battery pack balancing circuit system according to claim 4, characterized in that: The switch tube includes a parasitic diode and a field effect tube; The cathode of the parasitic diode is connected to the drain of the field effect transistor, and the anode of the parasitic diode is connected to the source of the field effect transistor; The gate of the field effect tube is communicatively connected to the digital signal processing module.

7. The multi-coil battery pack balancing circuit system according to claim 4, characterized in that: The acquisition and comparison module includes a voltage and current detection circuit and a current zero-crossing detection circuit; The battery pack is connected to one end of the voltage and current detection circuit, and the other end of the voltage and current detection circuit is connected to the digital signal processing module; The other end of the parallel resonant capacitor is connected to one end of the current zero-crossing detection circuit, and the other end of the current zero-crossing detection circuit is connected to the digital signal processing module.

8. The multi-coil battery pack balancing circuit system according to claim 7, characterized in that: The voltage and current detection circuit includes a voltage measurement circuit and a current measurement circuit; One end of the voltage measurement circuit is connected to the positive electrode of the battery pack, and the other end of the voltage measurement circuit is connected to the digital signal processing module; One end of the current measurement circuit is connected to the negative electrode of the battery pack, and the other end of the current measurement circuit is connected to the digital signal processing module.

9. The multi-coil battery pack balancing circuit system according to claim 8, characterized in that: The voltage measurement circuit includes a first voltage resistor, a second voltage resistor, a third voltage resistor, a fourth voltage resistor, a fifth voltage resistor, a sixth voltage resistor, a seventh voltage resistor, a first voltage capacitor, a second voltage capacitor, a third voltage capacitor, a fourth voltage capacitor, a first voltage operational amplifier, a second voltage operational amplifier, a first voltage diode, and a second voltage diode; One end of the first voltage resistor is connected to the positive electrode of the battery pack, and the other end of the first voltage resistor is connected to one end of the second voltage resistor; One end of the first voltage capacitor is connected to the non-inverting input end of the first voltage operational amplifier, and the other end of the second voltage resistor is connected to the other end of the first voltage capacitor and the negative electrode of the battery pack respectively; One end of the third voltage resistor is connected to the inverting input end of the first voltage operational amplifier, and the other end of the third voltage resistor is connected to one end of the fourth voltage resistor and the output end of the first voltage operational amplifier respectively; The other end of the fourth voltage resistor is connected to one end of the fifth voltage resistor and one end of the second voltage capacitor respectively; One end of the third voltage capacitor is grounded, and the other end of the fifth voltage resistor is connected to the non-inverting input end of the second voltage operational amplifier and the other end of the third voltage capacitor respectively; The other end of the second voltage capacitor is connected to the inverting input end of the second voltage operational amplifier, and the output end of the second voltage operational amplifier is connected to the other end of the second voltage capacitor and one end of the sixth voltage resistor respectively; The other end of the sixth voltage resistor is respectively connected to one end of the fourth voltage capacitor, one end of the seventh voltage resistor, the cathode of the first voltage diode, and the anode of the second voltage diode; The other end of the fourth voltage capacitor, the other end of the seventh voltage resistor, and the anode of the first voltage diode are all grounded, and the cathode of the second voltage diode is externally connected to a 3.3V voltage port; The common ends of the anode of the first voltage diode and the cathode of the second voltage diode are both connected to the digital signal processing module.

10. The multi-coil battery pack balancing circuit system according to claim 8, characterized in that: The current measurement circuit includes a current sensor, a current operational amplifier, a first current resistor, a second current resistor, a third current resistor, a first current capacitor, a second current capacitor, a first current diode and a second current diode; The positive power port of the current sensor is connected to one end of the DC filter capacitor, and the negative power port of the current sensor is connected to the negative electrode of the battery pack; The output port of the current sensor is connected to the non-inverting input terminal of the current operational amplifier, and the non-inverting input terminal of the current operational amplifier is connected to one end of the first current resistor; The output end of the current operational amplifier is respectively connected to the other end of the first current resistor, one end of the second current resistor, and one end of the first current capacitor; The other end of the second current resistor is respectively connected to the other end of the first current capacitor, one end of the third current resistor, one end of the second current capacitor, the cathode of the first current diode, and the anode of the second current diode; The other end of the third current resistor, the other end of the second current capacitor, and the anode of the first current diode are all grounded, and the cathodes of the second current diodes are externally connected to a 3.3V voltage port; A common end of the cathode of the first current diode and an anode of the second current diode are both connected to the digital signal processing module.

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