CN110739749B - Active battery balancing circuit and control method using flyback transformer correlation - Google Patents
Active battery balancing circuit and control method using flyback transformer correlation Download PDFInfo
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- CN110739749B CN110739749B CN201911219191.XA CN201911219191A CN110739749B CN 110739749 B CN110739749 B CN 110739749B CN 201911219191 A CN201911219191 A CN 201911219191A CN 110739749 B CN110739749 B CN 110739749B
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- 238000000034 method Methods 0.000 title claims abstract description 19
- 238000005070 sampling Methods 0.000 claims abstract description 37
- 238000004804 winding Methods 0.000 claims abstract description 26
- 238000007599 discharging Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000010349 pulsation Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
- H02J7/0014—Circuits for equalisation of charge between batteries
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
- H02J7/0014—Circuits for equalisation of charge between batteries
- H02J7/0019—Circuits for equalisation of charge between batteries using switched or multiplexed charge circuits
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
- Secondary Cells (AREA)
Abstract
本发明公开了一种利用反激变压器各绕组电压被电池钳位的关联性的主动电池均衡电路，包括控制单元、驱动单元、充电电池组；在电池均衡充电前测试总的电压，算出所有电池组的平均电压；测试电路中每组电池组的电压，计算所有电池组的电压与平均电压的电压差值，根据电压差值与预先设定的阈值之间的关系，选择电池充电。该电路及方法使电池在任意时刻都能进行较大电流的均衡，使电池组内的所有单节电池能够同时充到他们的最高电压，和同时放到他们的最低电压，充分的提高电池组的容量及利用率，而且保持系统的简洁及高效率。利用单端反激变压器的简洁性及同一变压器绕组电压的关联性，减少变压器的个数，减少采样点。均衡快速。
The present invention discloses an active battery balancing circuit that utilizes the correlation of the voltage of each winding of a flyback transformer being clamped by a battery, including a control unit, a drive unit, and a charging battery pack; before the battery is balanced and charged, the total voltage is tested to calculate the average voltage of all battery packs; the voltage of each battery pack in the test circuit is tested, the voltage difference between the voltage of all battery packs and the average voltage is calculated, and the battery to be charged is selected according to the relationship between the voltage difference and a preset threshold. The circuit and method enable the battery to be balanced with a large current at any time, so that all single cells in the battery pack can be charged to their highest voltage at the same time, and discharged to their lowest voltage at the same time, fully improving the capacity and utilization of the battery pack, and maintaining the simplicity and high efficiency of the system. The simplicity of the single-ended flyback transformer and the correlation of the voltage of the same transformer winding are utilized to reduce the number of transformers and the sampling points. The balancing is fast.
Description
Technical Field
The invention belongs to the field of battery charging circuits, and particularly relates to an active battery equalization circuit utilizing relevance of flyback transformers and a control method thereof.
Background
Currently, in the application of battery power supply equipment, the actual work needs serial connection of multiple batteries, and the capacities of the batteries always have differences, if the batteries are not protected singly during charging or use, the batteries can overshoot or overdischarge, which can affect the service life of the batteries, and the capacities of the battery packs can not be fully utilized for protection.
The existing battery balancing technology is divided into active and passive technologies, passive energy consumption balancing is generally adopted, the energy consumption of the overcharged battery is discharged after the battery is full, the efficiency is low, the circuit efficiency of active balancing is high, but the system is complex, balancing work can be rarely carried out at any moment, and simultaneous balancing of a plurality of batteries is rarely carried out.
Disclosure of Invention
The invention aims to solve the technical problem of providing an active battery equalization circuit and a control method thereof which utilize the relevance of clamping by battery voltage of each winding of a flyback transformer, and solve the problem of unbalanced battery electric quantity in the charging and discharging processes of a battery pack in the prior art.
The invention adopts the following technical scheme for solving the technical problems:
An active battery equalization circuit utilizing relevance of flyback transformers comprises a control unit, a driving unit and a rechargeable battery pack, wherein the control unit comprises a driving circuit, a voltage sampling circuit, a current sampling circuit and a power supply circuit, the driving unit comprises more than two groups of branches consisting of driving transistors and flyback transformers, each branch is output and connected with the battery pack after being subjected to flyback rectification to charge the battery pack, an output end winding of each flyback transformer comprises two output ends, each output end is connected with one battery, one end of an input end winding of each flyback transformer is connected with a main power supply, the other end of the input end winding of each flyback transformer is connected with the output end of each driving transistor, the input ends of the driving transistors are connected with the driving circuit, the common ends of the driving transistors are grounded, the voltage sampling circuit is correspondingly connected with the positive electrode of each battery pack, and the current sampling circuit is correspondingly connected with the common end of each driving transistor.
The output end winding of each flyback transformer comprises two output ends which are respectively connected with the positive electrode and the negative electrode of the two series batteries through diodes, and the middle point of the output end winding of the flyback transformer is connected with the middle point of the two series batteries.
The power input end of the power circuit is connected with the positive electrode of at least one battery.
The control method of the active battery equalization circuit utilizing the relevance of the flyback transformer comprises the following steps:
Step 1, testing total voltage before equalizing charge of batteries, and calculating average voltage of all battery packs;
step 2, testing the voltage of each group of battery packs in the circuit, calculating the voltage difference between the voltage of all the battery packs and the average voltage,
Step 3, judging the relation between the voltage difference value and a preset threshold value, executing step 4 when any group of voltage difference values are lower than the preset threshold value, otherwise, executing step 5;
step 4, opening a flyback transformer corresponding to the battery pack to charge the battery pack, stopping charging after a preset time is spent on charging, and returning to the step 2 and the step 3 until the voltages of all the battery packs are consistent;
and 5, stopping charging all the battery packs, waiting for a period of time, and returning to the step 2.
Compared with the prior art, the invention has the following beneficial effects:
1. The battery can balance larger current at any time, so that all single batteries in the battery pack can be charged to the highest voltage and simultaneously discharged to the lowest voltage, the capacity and the utilization rate of the battery pack are fully improved, and the simplicity and the high efficiency of the system are maintained.
2. The simplicity of the single-ended flyback transformer and the relevance of the same transformer winding voltage are utilized, so that the number of transformers is reduced, and sampling points are reduced.
3. Current is extracted from the overall voltage, the weaker battery is replenished, and the balancing is rapid.
4. The power input end of the power circuit is connected with the anode of a battery with proper voltage, and the system power is simplified.
Drawings
Fig. 1 is a schematic diagram of a battery equalization circuit of the present invention.
Detailed Description
The construction and operation of the present invention will be further described with reference to the accompanying drawings.
The invention provides a technology for balancing a battery pack by utilizing a plurality of low-power flyback switching power supplies, which utilizes the relevance of different winding voltages of the same transformer, greatly simplifies a balancing circuit, and can also perform balancing work of the battery at any time of charging and discharging. The circuit is simple, and can perform equalization activity of multiple batteries at any time.
The active battery equalization circuit utilizing relevance of the flyback transformer comprises a control unit, a driving unit and a rechargeable battery pack, wherein the control unit comprises a driving circuit, a voltage sampling circuit, a current sampling circuit and a power supply circuit, the driving unit comprises more than two groups of branches consisting of driving transistors and the flyback transformer, each branch output is connected with the battery pack after flyback rectification to charge the battery pack, an output end winding of each flyback transformer comprises two output ends, each output end is connected with one battery, one end of an input end winding of the flyback transformer is connected with the power supply, the other end of the input end winding of the flyback transformer is connected with the output end of the driving transistor, the input end of the driving transistor is connected with the driving circuit, the public end of the driving transistor is grounded, the voltage sampling circuit is correspondingly connected with the positive electrode of each battery pack, and the current sampling circuit is correspondingly connected with the public end of each driving transistor.
The output end winding of each flyback transformer comprises two output ends which are respectively connected with the positive electrode and the negative electrode of the two series batteries through diodes, and the middle point of the output end winding of the flyback transformer is connected with the middle point of the two series batteries.
The power input end of the power circuit is connected with the positive electrode of at least one battery.
The control method of the active battery equalization circuit utilizing the relevance of the flyback transformer comprises the following steps:
Step 1, testing total voltage before equalizing charge of batteries, and calculating average voltage of all battery packs;
step 2, testing the voltage of each group of battery packs in the circuit, calculating the voltage difference between the voltage of all the battery packs and the average voltage,
Step 3, judging the relation between the voltage difference value and a preset threshold value, executing step 4 when any group of voltage difference values are lower than the preset threshold value, otherwise, executing step 5;
step 4, opening a flyback transformer corresponding to the battery pack to charge the battery pack, stopping charging after a preset time is spent on charging, and returning to the step 2 and the step 3 until the voltages of all the battery packs are consistent;
and 5, stopping charging all the battery packs, waiting for a period of time, and returning to the step 2.
In a specific embodiment, as shown in fig. 1:
The active battery equalization circuit utilizing relevance of flyback transformers comprises a control unit, a driving unit and a rechargeable battery pack, wherein the control unit comprises a control singlechip, a driving circuit, a voltage sampling circuit, a current sampling circuit and a power supply circuit which are connected with the control singlechip, the driving unit comprises four groups of flyback circuit branches consisting of a driving MOS tube MA, MB, MC, MD and a flyback transformer TA, TB, TC, TD, the two groups of voltages output by the transformers are subjected to flyback rectification to be charged into battery packs A, B, C and D, the battery packs A are formed by serially connecting batteries A1 and A2, the battery packs B, C and D are respectively formed by B1, B2, C1, C2, D1 and D2, and the current sampling circuit comprises sampling resistors RA, RB, RC, RD. The circuit topology structure is described in detail below by taking a flyback circuit branch corresponding to a battery pack A as an example, an output end winding of a flyback transformer TA comprises two output ends which are respectively connected with batteries A1 and A2, one end of an input end winding of the flyback transformer TA is connected with a power supply, the other end of the input end winding of the flyback transformer TA is connected with a drain electrode of a driving MOS tube, a grid electrode of the driving MOS tube is connected with a driving circuit, a source electrode of the driving MOS tube is grounded after passing through a sampling resistor RA, and a voltage sampling circuit is correspondingly connected with an anode of the battery A2.
The output end winding of the flyback transformer TA comprises two output ends, the first output end is connected with the positive pole of the battery A2 in the morning through a diode DA2, the second output end is connected with the negative pole of the battery A1 through a reverse diode DA1, the middle point of the output end winding of the flyback transformer TA is connected with the middle points of the batteries A1 and A2 in series, and the circuit is used for reducing half of battery voltage sampling.
The power for the control system is supplied by a battery with a portion of the appropriate voltage being equalized.
The power input end of the power circuit is connected with the positive electrode of a battery with proper voltage, the embodiment is connected with the positive electrode of the battery B2, and the voltage can also be connected with the positive electrode of the battery A2 or the positive electrode of other batteries with proper voltages.
The working process of the equalizing circuit is as follows:
When the system control singlechip detects that the voltage of the battery pack A is lower than the average value, the MOS tube MA is pulsed through the driving circuit, the two symmetrical windings of the transformer TA are controlled to charge the batteries A1 and A2, and when the voltages of the batteries A1 and A2 are asymmetric, the transformer preferentially charges the battery with lower voltage. Thus, after a period of time, the voltages of the two batteries are automatically close, when the voltages of the two batteries are close, the current is automatically distributed according to the internal resistance of the batteries, and when the voltages of the two batteries reach the set voltage, the control circuit turns off the pulse of the power tube MA through the driving circuit to control the TA to turn off the charging circuit.
The control method of the equalization circuit comprises the following steps:
Step 1, testing total voltage before equalizing charge of batteries, and calculating average voltage of all battery packs;
step 2, testing the voltage of each group of battery packs in the circuit, calculating the voltage difference between the voltage of all the battery packs and the average voltage,
Step 3, judging the relation between the voltage difference value and a preset threshold value, executing step 4 when any group of voltage difference values are lower than the preset threshold value, otherwise, executing step 5;
step 4, opening a flyback transformer corresponding to the battery pack to charge the battery pack, stopping charging after a preset time is spent on charging, and returning to the step 2 and the step 3 until the voltages of all the battery packs are consistent;
And 5, stopping charging all the battery packs, waiting for a short period of time, and returning to the step 2.
In step 3 of this embodiment, the preset threshold is 1% of the average voltage, and in step 4, the preset charging time is one minute.
The small time in the step 5 can be set according to the needs, and a person skilled in the art can understand the specific meaning represented by the small time, and can set according to the needs without giving out specific time.
For example, in the figure, when the voltages of the battery groups A and C are lower than the average value, the charging circuits of the battery groups A and C are opened to charge the battery groups A and C, the voltages of the battery groups A and C are increased after charging, the voltages of the battery groups B and D are reduced, and if the voltages of the battery groups A and C are increased to the average voltage, the battery groups A and C are only charged in the next period, and the process is repeated until all the voltages are within the error range.
The equalization circuit has a charging protection function, and specifically comprises the following steps:
The charging process can be carried out at any time of charging and discharging, and the battery can be fully utilized. However, when the voltage of a certain battery is too low, the transformer for charging the battery cannot be reset, and the input current of the transformer is increased suddenly, at this time, pulse width charging is reduced, if the voltage cannot be increased after a period of charging, the battery is damaged, and the system can prompt the repair or replacement of the battery.
All power supply circuits of the equalizing circuit are provided by batteries of the system, wherein a control power supply of the system is powered by the batteries and is connected to the connection parts of the four batteries, and the batteries are unbalanced under the general condition, but because the equalization of the system happens at any time, the equalizing circuit can automatically increase current to power the power supply without influencing the equalization use of the batteries, and the control power supply can be simplified.
The working principle and working process of the sampling circuit of the equalizing circuit are as follows:
The sampling circuit of the equalizing circuit is divided into voltage sampling and current sampling, the voltage sampling corresponds to the current sampling one by one, the battery voltage of each two groups is measured, the charging current and the voltage sampling are formed by resistor voltage division, when the battery voltages are the same, the voltages on the AD sampling chips are the same, and the current sampling is amplified by an amplifier and then is sent to the AD sampling chips.
Average from the highest voltage sample, automatically equalize the battery voltage under the same transformer,
The control method for sampling pulsation sampling improves the sampling precision of the voltage, namely, a short charging period is set, sampling is not carried out during charging, charging is not carried out during sampling, and the influence of charging on sampling is avoided.
The preferred embodiments of the present invention have been described above. It is to be understood that the invention is not limited to the particular embodiments described above, in which circuits, devices and structures not described in detail are to be understood as being implemented in a manner common to the art, and that any person skilled in the art may make many possible variations and modifications to the technical solution of the invention using the methods and technical contents disclosed above, or be modified to equivalent embodiments without affecting the spirit of the invention, without departing from the scope of the technical solution of the invention. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.
Claims (3)
1. The control method of the active battery equalization circuit utilizing relevance of flyback transformers comprises a control unit, a driving unit and a rechargeable battery pack, wherein the control unit comprises a driving circuit, a voltage sampling circuit, a current sampling circuit and a power supply circuit, the driving unit comprises more than two groups of branches consisting of driving transistors and flyback transformers, each branch output is connected with the battery pack after flyback rectification to charge the battery pack, an output end winding of each flyback transformer comprises two output ends, each output end is connected with a battery, one end of an input end winding of each flyback transformer is connected with a main power supply, the other end of the input end winding of each flyback transformer is connected with the output end of each driving transistor, the input ends of the driving transistors are connected with the driving circuit, the common ends of the driving transistors are grounded, the voltage sampling circuit is correspondingly connected with the positive electrode of each battery pack, and the current sampling circuit is correspondingly connected with the common end of each driving transistor, and the control method is characterized by comprising the following steps:
Step 1, testing total voltage before equalizing charge of batteries, and calculating average voltage of all battery packs;
step 2, testing the voltage of each group of battery packs in the circuit, calculating the voltage difference between the voltage of all the battery packs and the average voltage,
Step 3, judging the relation between the voltage difference value and a preset threshold value, executing step 4 when any group of voltage difference values are lower than the preset threshold value, otherwise, executing step 5;
step 4, opening a flyback transformer corresponding to the battery pack to charge the battery pack, stopping charging after a preset time is spent on charging, and returning to the step 2 and the step 3 until the voltages of all the battery packs are consistent;
and 5, stopping charging all the battery packs, waiting for a period of time, and returning to the step 2.
2. The method for controlling the active battery equalization circuit utilizing the correlation of flyback transformers according to claim 1, wherein the output terminal windings of each flyback transformer comprise two output terminals which are respectively connected with the positive poles and the negative poles of the two series batteries through diodes, and the middle point of the output terminal windings of the flyback transformers is connected with the middle points of the two series batteries.
3. The method of claim 1, wherein the power input of the power circuit is connected to the positive electrode of at least one battery.
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