A DC protection power supply system and battery balancing control method thereof

Abstract

The present invention relates to a DC protection power supply system and a battery balancing control method thereof. The DC protection power supply system comprises: a battery pack, a bidirectional DC / DC conversion module; the battery pack comprises: a plurality of sub-battery packs connected in series in sequence; the bidirectional DC / DC conversion module comprises: a plurality of DC / DC sub-conversion modules arranged corresponding to the plurality of sub-battery packs; the method comprises: obtaining the current value of the battery pack; obtaining the minimum balancing value; judging whether the battery pack needs to be balanced according to the current value of the battery pack; if so, controlling the bidirectional DC / DC conversion module to balance the battery pack according to the minimum balancing value. The present invention can balance the battery pack discharge imbalance caused by short circuit in the battery pack, the discharge imbalance caused by the unbalanced number of single battery cells, or the battery voltage imbalance caused by long-term use, etc. It is not affected by the balancing equipment, has a good balancing effect, and improves the service life and reliability of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of battery balancing control, and more specifically, to a DC protection power supply system and a battery balancing control method thereof. Background Art

[0002] In the existing DC guard power supply system, when boosting the voltage from the battery group to the DC bus, there is no reverse charging of the battery. When the battery is unbalanced, a battery inspector (a battery inspector with balancing function or a battery management system) is used for balancing. However, the balancing current of the battery inspector is generally around 1A. If the battery group is broken, the battery voltage of a certain group will not be boosted and discharged to the outside, which will cause the boost and discharge of the batteries in other groups to be seriously unbalanced, and the battery inspector cannot achieve balancing at this time.

[0003] Alternatively, due to the uneven number of battery cells in each subgroup of the battery pack, there will be an imbalance in the current output to the DC bus, which will lead to uneven battery discharge. Alternatively, even if the number of battery cells in each subgroup of the battery pack is the same, long-term use will still lead to uneven battery voltage. Alternatively, when controlling the charging and self-test of the battery subgroups, there may be inconsistencies in time and current, which will also lead to uneven battery voltage over a long period of time. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a DC protection power supply system and a battery balancing control method thereof in view of the above-mentioned defects of the prior art.

[0005] The technical solution adopted by the present invention to solve the technical problem is: construct a battery balancing control method for a DC protection power supply system, which is applied to the DC protection power supply system, the DC protection power supply system includes: a battery pack, a bidirectional DC / DC conversion module; the battery pack includes: a plurality of sub-battery packs connected in series in sequence; the bidirectional DC / DC conversion module includes: a plurality of DC / DC sub-conversion modules arranged corresponding to the plurality of sub-battery packs; the method includes:

[0006] Obtaining a current value of the battery pack;

[0007] Get the minimum equilibrium value;

[0008] Determining whether it is necessary to perform balancing control on the battery pack according to the current value of the battery pack;

[0009] If so, the bidirectional DC / DC conversion module is controlled according to the minimum balancing value to perform balancing control on the battery pack.

[0010] In the battery balancing control method of the DC guard power system of the present invention, judging whether it is necessary to perform balancing control on the battery group according to the current value of the battery group includes:

[0011] Determining whether the current value of the battery pack is greater than zero;

[0012] If yes, it is determined that the battery pack needs to be balanced;

[0013] If not, it is determined that balancing control of the battery pack is not required.

[0014] In the battery balancing control method of the DC guard power system of the present invention, controlling the bidirectional DC / DC conversion module to perform balancing control on the battery group according to the sub-battery group information includes:

[0015] Obtaining the current state of the battery pack;

[0016] Determining whether the battery pack is in a balanced state according to the current state of the battery pack;

[0017] If so, adopting a first balancing mode to perform balancing control on the battery pack;

[0018] If not, the second balancing mode is adopted to perform balancing control on the battery pack.

[0019] In the battery balancing control method of the DC protection power supply system of the present invention, if the battery group is balanced by using the first balancing mode, the battery group is balanced by using the first balancing mode, which includes:

[0020] If the battery pack is currently in a balanced state, obtaining the battery pole temperature in the battery;

[0021] Whether to continue to perform balancing control on the battery pack is determined according to the battery pole temperature.

[0022] In the battery balancing control method of the DC guard power supply system of the present invention, judging whether to continue to perform balancing control on the battery group according to the battery pole temperature includes:

[0023] If the battery pole temperature is greater than a preset temperature, then stopping the balancing control of the battery pack;

[0024] If the battery pole temperature is lower than the preset temperature, then:

[0025] Calculate the equalization voltage of each sub-battery group according to the group voltage value of each sub-battery group and the number of single cells in each sub-battery group;

[0026] Selecting a maximum balancing voltage and a minimum balancing voltage from the balancing voltages of each sub-battery group;

[0027] The battery group is balanced and controlled according to the group voltage value of each sub-battery group, the maximum balanced voltage, the minimum balanced voltage and the minimum balanced value.

[0028] In the battery balancing control method of the DC protection power supply system of the present invention, if not, using the second balancing mode to balance the battery group includes:

[0029] If the battery pack is currently in an unbalanced state, then:

[0030] Calculate the equalization voltage of each sub-battery group according to the group voltage value of each sub-battery group and the number of single cells in each sub-battery group;

[0031] Selecting a maximum balancing voltage and a minimum balancing voltage from the balancing voltages of each sub-battery group;

[0032] Whether to continue to perform balancing control on the battery group is determined according to the maximum balancing voltage, the minimum balancing voltage and the minimum balancing value.

[0033] In the battery balancing control method of the DC guard power system of the present invention, judging whether to continue to perform balancing control on the battery group according to the maximum balancing voltage, the minimum balancing voltage and the minimum balancing value includes:

[0034] Difference between the maximum balancing voltage and the minimum balancing voltage and taking the absolute value;

[0035] comparing the absolute value with the minimum equilibrium value;

[0036] If the absolute value is less than the minimum balancing value, the balancing control is stopped;

[0037] If the absolute value is greater than the minimum equilibrium value, then:

[0038] Calculating an average voltage according to the maximum equalizing voltage and the minimum equalizing voltage;

[0039] Determine, according to the equalized voltage of each of the sub-battery groups, a first quantity greater than the average voltage and a second quantity less than the average voltage;

[0040] comparing the first amount to a value that is less than the second amount;

[0041] If the first number is less than the second number, discharging and balancing the high-voltage sub-battery group;

[0042] If the first number is greater than the second number, charging and balancing is performed on the low-voltage sub-battery group.

[0043] In the battery balancing control method of the DC guard power system of the present invention, if the first number is less than the second number, discharging and balancing the high-voltage sub-battery group includes:

[0044] Controlling the DC / DC sub-conversion module corresponding to the sub-battery group whose equalization voltage is greater than the average voltage to perform discharge equalization on the sub-battery group whose equalization voltage is greater than the average voltage;

[0045] Obtaining the current of the battery pack;

[0046] Comparing the current of the battery pack with a first preset current or a second preset current;

[0047] If the current current of the battery pack is greater than the first preset current, reducing the balanced discharge current of the DC / DC sub-conversion module;

[0048] If the current current of the battery pack is less than the second preset current, increasing the balanced discharge current of the DC / DC sub-conversion module;

[0049] If the current current of the storage battery group is equal to the second preset current or the balanced discharge current is equal to the first preset current, the balanced discharge is stopped.

[0050] In the battery balancing control method of the DC guard power system of the present invention, the charging balancing of the low-voltage sub-battery group includes:

[0051] Controlling the sub-battery group whose equalization voltage is less than the average voltage to charge and equalize the sub-battery group whose equalization voltage is less than the average voltage to the corresponding DC / DC sub-conversion module;

[0052] Acquire the current current of the storage battery group and the current charging current of the sub-battery group whose equalization voltage is less than the average voltage;

[0053] Charging equalization control is performed according to the current current of the storage battery group and the current charging current of the sub-battery group whose equalization voltage is less than the average voltage.

[0054] The present invention also provides a DC protection power supply system, comprising: a battery pack, a bidirectional DC / DC conversion module and a control unit; the battery pack comprises: a plurality of sub-battery packs connected in series in sequence; the bidirectional DC / DC conversion module comprises: a plurality of DC / DC sub-conversion modules arranged corresponding to the plurality of sub-battery packs; the control unit is used to:

[0055] Obtaining a current value of the battery pack;

[0056] Get the minimum equilibrium value;

[0057] Determining whether it is necessary to perform balancing control on the battery pack according to the current value of the battery pack;

[0058] If so, the bidirectional DC / DC conversion module is controlled according to the minimum balancing value to perform balancing control on the battery pack.

[0059] The implementation of the DC protection power supply system and the battery balancing control method of the present invention has the following beneficial effects: the DC protection power supply system includes: a battery pack, a bidirectional DC / DC conversion module; the battery pack includes: a plurality of sub-battery packs connected in series in sequence; the bidirectional DC / DC conversion module includes: a plurality of DC / DC sub-conversion modules corresponding to the plurality of sub-battery packs; the method includes: obtaining the current value of the battery pack; obtaining the minimum balancing value; judging whether the battery pack needs to be balanced according to the current value of the battery pack; if so, controlling the bidirectional DC / DC conversion module to balance the battery pack according to the minimum balancing value. The present invention can balance the battery pack discharge imbalance caused by short circuit in the battery pack, the discharge imbalance caused by the unbalanced number of single battery cells, or the battery voltage imbalance caused by long-term use, etc. It is not affected by the balancing equipment, has a good balancing effect, and improves the service life and reliability of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0061] Figure 1 It is a flowchart of a battery balancing control method of a DC guard power system provided by an embodiment of the present invention;

[0062] Figure 2 It is a principle block diagram of a DC protection power supply system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0063] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0064] refer to Figure 1 , which is a flow chart of an optional embodiment of a battery balancing control method for a DC guard power supply system provided by the present invention.

[0065] The battery balancing control method of the DC protection power supply system can be applied to the DC protection power supply system. The DC protection power supply system includes: a battery pack 12 and a bidirectional DC / DC conversion module 13. The battery pack 12 includes: a plurality of sub-battery packs connected in series; the bidirectional DC / DC conversion module 13 includes: a plurality of DC / DC sub-conversion modules corresponding to the plurality of sub-battery packs.

[0066] Specifically, Figure 1 As shown, the battery balancing control method of the DC guard power system includes:

[0067] Step S101 : obtaining the current value of the battery pack 12 .

[0068] It can be understood that the current value of the battery pack 12 is the charge and discharge current of the entire battery pack 12, which is a real-time measurement value and can be positive or negative. When the battery pack 12 is in a charging state, the current value is positive; when the battery pack 12 is in a discharging state, the current value is negative.

[0069] Step S102: Obtain the minimum balance value.

[0070] Optionally, the minimum balancing value may be preset according to the configuration of the battery pack 12. The minimum balancing value is used as a reference for starting or stopping balancing of the battery pack 12.

[0071] Step S103 : judging whether it is necessary to perform balancing control on the battery group 12 according to the current value of the battery group 12 .

[0072] In some embodiments, determining whether the battery pack 12 needs to be balanced controlled based on the current value of the battery pack 12 includes: determining whether the current value of the battery pack 12 is greater than zero; if so, determining that the battery pack 12 needs to be balanced controlled; if not, determining that the battery pack 12 does not need to be balanced controlled.

[0073] It can be understood that when the current value of the battery group 12 is less than 0, it means that the battery group 12 is in a discharging state and no balancing operation control is performed; when the current value of the battery group 12 is greater than 0, it means that the battery group 12 is in a charging state and balancing operation control can be performed according to the charging condition of the battery group 12.

[0074] Step S104 : If yes, the bidirectional DC / DC conversion module 13 is controlled to perform balancing control on the battery group 12 according to the minimum balancing value.

[0075] In some embodiments, controlling the bidirectional DC / DC conversion module 13 to perform balancing control on the battery group 12 according to the sub-battery group information includes: obtaining the current state of the battery group 12; judging whether the battery group 12 is in a balanced state according to the current state of the battery group 12; if so, performing balancing control on the battery group 12 using a first balancing mode; if not, performing balancing control on the battery group 12 using a second balancing mode.

[0076] In some embodiments, if so, using the first balancing mode to perform balancing control on the battery pack 12 includes: if the battery pack 12 is currently in a balanced state, obtaining the battery pole temperature in the battery; and determining whether to continue to perform balancing control on the battery pack 12 according to the battery pole temperature.

[0077] Optionally, judging whether to continue to perform balancing control on the battery group 12 according to the battery pole temperature includes: if the battery pole temperature is greater than a preset temperature, stopping the balancing control on the battery group 12. If the battery pole temperature is less than the preset temperature, then: calculating the balancing voltage of each sub-battery group according to the group voltage value of each sub-battery group and the number of single cells in each sub-battery group; selecting the maximum balancing voltage and the minimum balancing voltage from the balancing voltages of each sub-battery group; performing balancing control on the battery group 12 according to the group voltage value, the maximum balancing voltage, the minimum balancing voltage and the minimum balancing value of each sub-battery group.

[0078] Optionally, the group voltage value of each sub-battery group is the real-time voltage of each sub-battery group, the maximum equalization voltage is the current maximum value of the real-time voltages of all sub-battery groups, and the minimum equalization voltage is the current minimum value of the real-time voltages of all sub-battery groups.

[0079] Optionally, performing balancing control on the battery group 12 according to the group voltage value, the maximum balancing voltage, the minimum balancing voltage and the minimum balancing value of each sub-battery group includes:

[0080] If a sub-battery group is in the discharge balancing state, it is determined whether the group voltage value of the sub-battery group is less than half of the sum of the minimum balancing voltage and the minimum balancing value. If so, the battery discharge balancing of the sub-battery group is exited. If not, the DC / DC sub-conversion module corresponding to the sub-battery group is controlled to continue the charge balancing control of the sub-battery group; if the discharge balancing of all sub-battery groups is terminated, the balancing is terminated. Similarly, the balancing control of other battery groups in the discharge balancing state is the same as that of the sub-battery group.

[0081] If a sub-battery group is in the charge balancing state, it is determined whether the group voltage value of the sub-battery group is greater than half of the difference between the maximum balancing voltage and the minimum balancing value. If so, the battery charge balancing of the sub-battery group is exited. If not, the sub-battery group is controlled to continue discharging to the DC / DC sub-conversion module corresponding to it; if the charge balancing of all sub-battery groups is terminated, the balancing is terminated.

[0082] If not, in some embodiments, the second balancing mode is used to perform balancing control on the battery group 12, including: if the battery group 12 is currently in an unbalanced state, then: calculating the balancing voltage of each sub-battery group according to the group voltage value of each sub-battery group and the number of single cells in each sub-battery group; selecting the maximum balancing voltage and the minimum balancing voltage from the balancing voltages of each sub-battery group; judging whether to continue to perform balancing control on the battery group 12 according to the maximum balancing voltage, the minimum balancing voltage and the minimum balancing value.

[0083] Optionally, judging whether to continue to perform balancing control on the battery group 12 based on the maximum balancing voltage, the minimum balancing voltage and the minimum balancing value includes: subtracting the maximum balancing voltage from the minimum balancing voltage and taking the absolute value; comparing the absolute value with the minimum balancing value; if the absolute value is less than the minimum balancing value, stopping the balancing control; if the absolute value is greater than the minimum balancing value, then: calculating the average voltage based on the maximum balancing voltage and the minimum balancing voltage; determining a first number greater than the average voltage and a second number less than the average voltage based on the balancing voltage of each sub-battery group; comparing the first number with a number less than the second number; if the first number is less than the second number, performing discharge balancing on the high-voltage sub-battery group and charging balancing on the low-voltage sub-battery group.

[0084] Optionally, if the first number is less than the second number, discharging and balancing the high-voltage sub-battery group includes: controlling the DC / DC sub-conversion module corresponding to the sub-battery group whose balancing voltage is greater than the average voltage to discharge and balance the sub-battery group whose balancing voltage is greater than the average voltage; obtaining the current current of the battery group 12; comparing the current current of the battery group 12 with the first preset current or the second preset current; if the current current of the battery group 12 is greater than the first preset current, reducing the balancing discharge current of the DC / DC sub-conversion module; if the current current of the battery group 12 is less than the second preset current, increasing the balancing discharge current of the DC / DC sub-conversion module; if the current current of the battery group 12 is equal to the second preset current or the balancing discharge current is equal to the first preset current, stopping the balancing discharge.

[0085] Specifically, assume that during the balancing process, the current current of the battery pack 12 is I 0当 , the first preset current is 1.5C 10 , the second preset current is 1C 10, where C10 is the discharge capacity of the entire battery pack for 1210 hours.

[0086] When performing discharge balance control, if I 0当 Greater than 1.5C 10 , the balanced discharge current of the DC / DC sub-conversion module that is discharging is reduced; if I 0当 Less than 1.5C 10 When the discharge current of the DC / DC sub-conversion module is equal to 1C, the balanced discharge current of the DC / DC sub-conversion module is increased; if the discharge current of the DC / DC sub-conversion module is equal to 1C 10 or I 0当 Equal to 1.5C 10 When , no balancing operation is performed.

[0087] Optionally, charging and balancing the low-voltage sub-battery group includes: controlling the sub-battery group with a balancing voltage less than the average voltage to charge and balance the sub-battery group with a balancing voltage less than the average voltage to the corresponding DC / DC sub-conversion module; obtaining the current current of the battery group 12 and the current charging current of the sub-battery group with a balancing voltage less than the average voltage; and performing charging and balancing control according to the current current of the battery group 12 and the current charging current of the sub-battery group with a balancing voltage less than the average voltage. Among them, charging and balancing control according to the current current of the battery group 12 and the current charging current of the sub-battery group with a balancing voltage less than the average voltage includes: summing the current current of the battery group 12 and the current charging current of the sub-battery group to obtain the sum of the current current of the battery group 12 and the current charging current of the sub-battery group. Determine whether the sum is greater than the first preset current. If so, reduce the current charging current of the sub-battery group; if the sum is less than the third preset current and the current charging current of the sub-battery group is less than the fourth preset current, increase the current charging current of the sub-battery group. When it is other cases, no operation is performed.

[0088] Specifically, assume that during the balancing process, the current current of the battery pack 12 is I 0当 , the first preset current is 1.5C 10 , the second preset current is 1C 10 , the third preset current is 1.2C 10 , the fourth preset current is 0.1C 10 , where C 10 It is the discharge capacity of the entire battery pack for 1210 hours. n充 is the current charging current of any sub-battery group.

[0089] When performing charge balancing control, if I 0当 +I n充 >1.5C 10, then reduce the current charging current of the DC / DC sub-conversion module to the sub-battery group (i.e. reduce I n充 ); if I 0当 +I n充 <1.2C 10 And I n充 <0.1C 10 When the DC / DC sub-conversion module increases the current charging current of the sub-battery group (i.e., increases I n充 ). In other cases, no operation is performed.

[0090] Assume that the battery value of a battery pack 12 is V0, and the current value of the battery pack 12 is I0; the battery pack 12 is divided into a first sub-battery pack, a second sub-battery pack, a third sub-battery pack and a fourth sub-battery pack, a total of 4 sub-battery packs; the bidirectional DC / DC conversion module 13 is correspondingly provided with a first DC / DC sub-conversion module, a second DC / DC sub-conversion module, a third DC / DC sub-conversion module and a fourth DC / DC sub-conversion module, a total of 4 DC / DC sub-conversion modules; then v1, v2, v3 and v4 represent the group voltage value of the first sub-battery pack, the group voltage value of the second sub-battery pack, the group voltage value of the third sub-battery pack and the group voltage value of the fourth sub-battery pack respectively. Assume N b1 、N b2 、N b3 and N b4 denote the number of single cells in the first sub-battery group, the number of single cells in the second sub-battery group, the number of single cells in the third sub-battery group, and the number of single cells in the fourth sub-battery group. b1 、v b2 、v b3 and v b4 represents the equalization voltage of the first sub-battery group, the equalization voltage of the second sub-battery group, the equalization voltage of the third sub-battery group, and the equalization voltage of the fourth sub-battery group, v bmax Indicates the maximum equilibrium voltage, v bmin Indicates the minimum equilibrium voltage. v bc represents the minimum equilibrium value, v b Indicates the average voltage, N GTR represents {v b1 ,v b2 …v b4} is greater than v b The number (first number), N LSS represents {v b1 ,v b2 …v b4} is less than v b 's quantity (second quantity).

[0091] The specific implementation steps are as follows:

[0092] Step 1: Judge according to I0. If I0 is greater than 0, balance control is performed and step 2 is executed. Otherwise, if I0 is less than 0, if there is a balance operation currently, the balance operation control is exited and the control process ends; if there is no balance operation currently, the control process ends.

[0093] Step 2: Determine the current state of the battery pack 12. If there is no balancing operation (i.e., it is currently in a non-balancing state), then execute step 3; if there is a balancing operation (i.e., it is currently in a balancing state), then execute step 7.

[0094] Step 3: Determine |v bmax -v bmin |Is it greater than v bC If yes, execute step 4; if no, stop the operation.

[0095] Step 4: Calculate {v b1 ,v b2 …v bn} is greater than v b The number N GTR , and less than v b The number N LSS .

[0096] If N GTR <N LSS , execute the fifth step to discharge and balance the high-voltage sub-battery group; for the low-voltage sub-battery group, execute the sixth step to charge and balance the low-voltage battery.

[0097] Step 5: Control the high-voltage sub-battery group to discharge and balance the corresponding DC / DC sub-conversion module. 0当 Greater than 1.5C 10 When the balanced discharge current is reduced; if I 0当 Less than 1.5C 10 When the balanced discharge current is increased, the maximum value of the balanced discharge current is 1C 10 If the balanced discharge current is equal to 1C 10 or I 0当 Equal to 1.5C 10 If no operation is performed, the process will be exited and no further execution will be performed.

[0098] Step 6: Control the DC / DC sub-conversion module corresponding to the low-voltage sub-battery group to perform charge balancing control on the low-voltage sub-battery group. n充 >1.5C 10 , reduce I n充 ; If I0+I n <1.2C 10 And I n <0.1C10 , improve I n充 ; In other cases, do nothing, exit this process, and do not proceed further.

[0099] Step 7: If the temperature of the battery pole in the sub-battery group being balanced (including discharge balance or charge balance) is too high, stop the battery balancing operation (i.e. stop charging or discharging the sub-battery group) and end the balancing; otherwise, execute step 8.

[0100] Step 8: If the current is discharge balance control, if the v of the discharged sub-battery group bn <(v bmin +v bC / 2), exit the discharge balancing of this sub-battery group; if all discharge balancing is terminated, end the balancing; otherwise, execute the fifth step.

[0101] If the current control is charge balancing, if the v of the sub-battery group being charged bn >(v bmax -v bC / 2), exit the charge balancing of this sub-battery group; if all charge balancing is terminated, end the balancing; otherwise, execute step 6.

[0102] refer to Figure 2 , is a principle block diagram of an optional embodiment of a DC protection power supply system provided by the present invention. The DC protection power supply system can adopt the battery balancing control method disclosed in the embodiment of the present invention for balancing control.

[0103] Specifically, Figure 2 As shown, the DC protection power supply system includes: a battery pack 12, a bidirectional DC / DC conversion module 13 and a control unit 15; the battery pack 12 includes: a plurality of sub-battery packs connected in series in sequence; the bidirectional DC / DC conversion module 13 includes: a plurality of DC / DC sub-conversion modules arranged corresponding to the plurality of sub-battery packs; the control unit 15 is used to: obtain the current value of the battery pack 12; obtain the minimum balancing value; determine whether the battery pack 12 needs to be balanced according to the current value of the battery pack 12; if so, control the bidirectional DC / DC conversion module 13 to balance the battery pack 12 according to the minimum balancing value.

[0104] Furthermore, the DC protection power supply system also includes: a DC bus 14 and an AC / DC power supply module 11.

[0105] The AC / DC power supply module 11 is used to charge the battery pack 12 and supply power to the load through the DC bus 14 when the AC is in a normal state.

[0106] The battery pack 12 is used to supply power to the load via the DC bus 14 when the AC is abnormal.

[0107] The bidirectional DC / DC conversion module 13 is used to supply power to the load through the DC bus 14 when the AC is abnormal and the battery pack 12 is abnormal. Figure 2 As shown, the DC protection power supply system may further include: a first switch K1, the first switch K1 is used to control the on / off of the AC / DC power supply module 11 and the DC bus 14, that is, to control the connection or disconnection of the AC / DC power supply module 11.

[0108] Furthermore, if Figure 2 As shown, the DC protection power supply system may further include: a second switch K2, the second switch K2 is used to control the on-off of the battery pack 12 and the DC bus 14, that is, to control the connection or disconnection of the battery pack 12.

[0109] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0110] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0111] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0112] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot limit the scope of protection of the present invention. All equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A battery balancing control method for a DC protection power supply system, applied to a DC protection power supply system, characterized in that: The DC protection power supply system comprises: a battery pack, a bidirectional DC / DC conversion module; the battery pack comprises: a plurality of sub-battery packs connected in series in sequence; the bidirectional DC / DC conversion module comprises: a plurality of DC / DC sub-conversion modules arranged corresponding to the plurality of sub-battery packs; the method comprises: Obtaining a current value of the battery pack; Get the minimum equilibrium value; Determining whether it is necessary to perform balancing control on the battery pack according to the current value of the battery pack; If so, the bidirectional DC / DC conversion module is controlled according to the minimum balancing value to perform balancing control on the battery pack; the controlling the bidirectional DC / DC conversion module according to the minimum balancing value to perform balancing control on the battery pack includes: obtaining the current state of the battery pack; judging whether the battery pack is in a balanced state according to the current state of the battery pack; if so, the first balancing mode is used to perform balancing control on the battery pack; if not, the second balancing mode is used to perform balancing control on the battery pack; If so, adopting the first balancing mode to balance the battery group includes: if the battery group is currently in a balanced state, obtaining the battery pole temperature in the battery; judging whether to continue to balance the battery group according to the battery pole temperature; judging whether to continue to balance the battery group according to the battery pole temperature includes: if the battery pole temperature is greater than a preset temperature, stopping the balance control of the battery group; if the battery pole temperature is less than the preset temperature, then: calculating the balance voltage of each sub-battery group according to the group voltage value of each sub-battery group and the number of single cells in each sub-battery group; selecting the maximum balance voltage and the minimum balance voltage from the balance voltages of each sub-battery group; and performing balance control on the battery group according to the group voltage value of each sub-battery group, the maximum balance voltage, the minimum balance voltage and the minimum balance value; If not, adopting the second balancing mode to balance the battery group includes: if the battery group is currently in an unbalanced state, then: calculating the balancing voltage of each sub-battery group according to the group voltage value of each sub-battery group and the number of single cells in each sub-battery group; selecting the maximum balancing voltage and the minimum balancing voltage from the balancing voltages of each sub-battery group; judging whether to continue to balance the battery group according to the maximum balancing voltage, the minimum balancing voltage and the minimum balancing value; The determining whether to continue to perform equalization control on the battery pack according to the maximum equalization voltage, the minimum equalization voltage and the minimum equalization value comprises: Difference between the maximum balancing voltage and the minimum balancing voltage and taking the absolute value; comparing the absolute value with the minimum equilibrium value; If the absolute value is less than the minimum balancing value, the balancing control is stopped; If the absolute value is greater than the minimum equilibrium value, then: Calculating an average voltage according to the maximum equalizing voltage and the minimum equalizing voltage; Determine, according to the equalized voltage of each of the sub-battery groups, a first quantity greater than the average voltage and a second quantity less than the average voltage; comparing the first amount to the second amount; If the first number is smaller than the second number, discharge balancing is performed on the high-voltage sub-battery group, and charge balancing is performed on the low-voltage sub-battery group.

2. The battery balancing control method of the DC protection power supply system according to claim 1, characterized in that: The step of judging whether it is necessary to perform balancing control on the battery pack according to the current value of the battery pack comprises: Determining whether the current value of the battery pack is greater than zero; If yes, it is determined that the battery pack needs to be balanced; If not, it is determined that balancing control of the battery pack is not required.

3. The battery balancing control method of the DC protection power supply system according to claim 1, characterized in that: If the first number is less than the second number, discharging and balancing the high-voltage sub-battery group includes: Controlling the DC / DC sub-conversion module corresponding to the sub-battery group whose equalization voltage is greater than the average voltage to perform discharge equalization on the sub-battery group whose equalization voltage is greater than the average voltage; Obtaining the current of the battery pack; Comparing the current of the battery pack with a first preset current or a second preset current; If the current current of the battery pack is greater than the first preset current, reducing the balanced discharge current of the DC / DC sub-conversion module; If the current current of the battery pack is less than the second preset current, increasing the balanced discharge current of the DC / DC sub-conversion module; If the current current of the storage battery group is equal to the second preset current or the balanced discharge current is equal to the first preset current, the balanced discharge is stopped.

4. The battery balancing control method of the DC protection power supply system according to claim 1, characterized in that: The charging and balancing of the low-voltage sub-battery group includes: Controlling the sub-battery group whose equalization voltage is less than the average voltage to charge and equalize the sub-battery group whose equalization voltage is less than the average voltage to the corresponding DC / DC sub-conversion module; Acquire the current current of the storage battery group and the current charging current of the sub-battery group whose equalization voltage is less than the average voltage; Charging equalization control is performed according to the current current of the storage battery group and the current charging current of the sub-battery group whose equalization voltage is less than the average voltage.

5. A DC protection power supply system, characterized in that: include: Battery pack, bidirectional DC / DC conversion module and control unit; The battery pack includes: a plurality of sub-battery packs connected in series in sequence; the bidirectional DC / DC conversion module includes: a plurality of DC / DC sub-conversion modules arranged corresponding to the plurality of sub-battery packs; the control unit is used for: Obtaining a current value of the battery pack; Get the minimum equilibrium value; Determining whether it is necessary to perform balancing control on the battery pack according to the current value of the battery pack; If yes, controlling the bidirectional DC / DC conversion module to perform balancing control on the battery pack according to the minimum balancing value; The controlling the bidirectional DC / DC conversion module to balance the battery pack according to the minimum balance value comprises: obtaining the current state of the battery pack; judging whether the battery pack is in a balanced state according to the current state of the battery pack; if so, using a first balance mode to balance the battery pack; if not, using a second balance mode to balance the battery pack; If so, adopting the first balancing mode to balance the battery group includes: if the battery group is currently in a balanced state, obtaining the battery pole temperature in the battery; judging whether to continue to balance the battery group according to the battery pole temperature; judging whether to continue to balance the battery group according to the battery pole temperature includes: if the battery pole temperature is greater than a preset temperature, stopping the balance control of the battery group; if the battery pole temperature is less than the preset temperature, then: calculating the balance voltage of each sub-battery group according to the group voltage value of each sub-battery group and the number of single cells in each sub-battery group; selecting the maximum balance voltage and the minimum balance voltage from the balance voltages of each sub-battery group; and performing balance control on the battery group according to the group voltage value of each sub-battery group, the maximum balance voltage, the minimum balance voltage and the minimum balance value; If not, adopting the second balancing mode to balance the battery group includes: if the battery group is currently in an unbalanced state, then: calculating the balancing voltage of each sub-battery group according to the group voltage value of each sub-battery group and the number of single cells in each sub-battery group; selecting the maximum balancing voltage and the minimum balancing voltage from the balancing voltages of each sub-battery group; judging whether to continue to balance the battery group according to the maximum balancing voltage, the minimum balancing voltage and the minimum balancing value; The determining whether to continue to perform equalization control on the battery pack according to the maximum equalization voltage, the minimum equalization voltage and the minimum equalization value comprises: Difference between the maximum balancing voltage and the minimum balancing voltage and taking the absolute value; comparing the absolute value with the minimum equilibrium value; If the absolute value is less than the minimum balancing value, the balancing control is stopped; If the absolute value is greater than the minimum equilibrium value, then: Calculating an average voltage according to the maximum equalizing voltage and the minimum equalizing voltage; Determine, according to the equalized voltage of each of the sub-battery groups, a first quantity greater than the average voltage and a second quantity less than the average voltage; comparing the first amount to the second amount; If the first number is smaller than the second number, discharge balancing is performed on the high-voltage sub-battery group, and charge balancing is performed on the low-voltage sub-battery group.

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