Instantaneous switching over-current suppression method for charging pile of one-machine-two-charging structure based on delay switching strategy

Abstract

The application discloses a one-machine two-charging-structure charging pile instantaneous switching overcurrent suppression method based on a delay switching strategy, relates to a charging pile switching control strategy, and has a control object structure containing a charging device module capable of simultaneously providing services for two electric vehicles, a battery voltage acquisition module, a delay operation module and a relay switching control module. When the charging device is in a two-electric-vehicle charging switching state, the voltage difference between the batteries of the two electric vehicles is monitored through the battery voltage acquisition module, when the voltage difference exceeds a certain threshold value, the output value of the delay operation module is increased to increase the switching time difference value of the input side relays of the two groups of batteries, so that the instantaneous overcurrent caused by the relay parasitic capacitor in the charging battery switching process is suppressed, and the power battery and the charging system are protected from damage caused by overcurrent impact.

Description

Technical Field

[0001] This invention relates to a method for suppressing overcurrent during instantaneous switching of a charging pile with a dual-charger structure based on a delayed switching strategy, belonging to the technical field of power conversion devices. Background Technology

[0002] With the increasing number of electric vehicles, the construction of various supporting facilities for electric vehicles has also begun to develop rapidly. Some regions have begun to promote charging devices with a dual-charger structure, which can charge a second electric vehicle while simultaneously charging one, through automatic switching. However, the battery parameters of the two electric vehicles often differ, and their states of charge are also not the same, resulting in random voltage differences between the two batteries. At the same time, the relays connected in series on the two output lines of the charging pile will generate parasitic capacitance during rapid switching, causing instantaneous circulating current during the switching process between the two sets of power batteries. If the circulating current value is too large, it will endanger the safety of the charging pile and the power batteries.

[0003] like Figure 1 As shown, a voltage difference exists between the two batteries, which generates a circulating current during the instantaneous switching of the relay. Parasitic capacitance refers to the capacitive characteristics exhibited by inductors, resistors, and chip pins at high frequencies. In reality, the internal resistance of the relay is not very noticeable at low frequencies, but during high-frequency switching, the parasitic capacitance increases with frequency. The relay forms a loop due to this parasitic capacitance during high-frequency switching, and since there is a voltage difference between the two battery banks, the loop generates a transient overcurrent due to the potential difference.

[0004] To avoid the occurrence of the above situations that could endanger the safe and stable operation of charging piles and charging vehicles, this invention proposes an instantaneous switching overcurrent suppression method based on a delayed switching strategy. Summary of the Invention

[0005] The technical problem to be solved by this invention is to overcome the instantaneous overcurrent problem caused by the existing technical solutions. The invention provides a method for suppressing instantaneous overcurrent when switching between two charging piles with a one-machine-two-charger structure based on a delayed switching strategy. This method solves the problem of instantaneous circulating current between the two sets of power batteries during the instantaneous switching of the charging pile, and ensures the user's charging experience as long as the battery voltage difference does not exceed the threshold voltage.

[0006] The present invention specifically adopts the following technical solutions to achieve the above technical objectives:

[0007] In a first aspect, the present invention provides a method for suppressing instantaneous switching overcurrent in a charging pile with a dual-charger structure based on a delayed switching strategy, comprising:

[0008] In response to the charging pile output side completing the charging of battery one through the first relay, the charging is switched to battery two through the second relay to start charging. Before the relay is switched, the voltage difference ΔV between battery one and battery two is obtained.

[0009] Based on the voltage difference between battery one and battery two, the switching delay time Δt is calculated, including: in response to the voltage difference ΔV being greater than the preset threshold ΔVref, the switching delay time is increased;

[0010] The first relay is controlled to disconnect, and the closing time of the second relay is selected according to the switching delay time to complete the charging.

[0011] In some embodiments, calculating the switching delay time Δt based on the voltage difference between battery one and battery two further includes:

[0012] In response to a voltage difference ΔV being less than a preset threshold ΔVref, the switching delay time is reduced.

[0013] In some embodiments, obtaining the voltage difference ΔV between battery one and battery two includes:

[0014] Obtain the voltage values ​​of battery one and battery two before the relay is switched on;

[0015] Calculate the voltage difference between battery one and battery two based on their voltage values ​​before the relay is switched on.

[0016] In some embodiments, the instantaneous switching overcurrent suppression method for a dual-charger charging pile with a one-machine-two-charger structure based on a delayed switching strategy specifically includes the following steps:

[0017] Step 1: Detect the terminal voltage of battery one and battery two, and calculate the voltage difference between battery one and battery two;

[0018] Step 2: The voltage difference at the feedback terminal is sent to the delay calculation module to calculate the delay time;

[0019] Step 3: The first relay on the battery input side is disconnected;

[0020] Step 4: The second relay on the input side of battery 2 selects the closing time point according to the delay time to complete the charging connection, thereby reducing the instantaneous overcurrent caused by the parasitic capacitance of the relays during the rapid switching process of the two sets of battery input side relays, and achieving the purpose of protecting the charging device and the battery.

[0021] Secondly, the present invention provides a device for suppressing instantaneous switching overcurrent of a charging pile with a dual-charger structure based on a delayed switching strategy, comprising:

[0022] The battery voltage acquisition module is configured to: in response to the charging pile output side completing the charging of battery one through the first relay, switch to battery two to start charging through the second relay, and acquire the voltage difference ΔV between battery one and battery two before the relay is switched on;

[0023] The delay calculation module is configured to: calculate the switching delay time Δt based on the voltage difference between battery one and battery two, and send the switching delay time to the relay switching control module; wherein calculating the switching delay time Δt based on the voltage difference between battery one and battery two includes: increasing the switching delay time in response to the voltage difference ΔV being greater than a preset threshold ΔVref;

[0024] The relay switching control module is configured to: control the first relay to disconnect, and select the closing time of the second relay according to the switching delay time to complete the charging connection.

[0025] In some embodiments, the battery voltage acquisition module specifically includes:

[0026] The battery voltage acquisition unit is used to acquire the voltage values ​​of battery one and battery two before the relay is switched on;

[0027] The battery voltage difference calculation unit is used to calculate the voltage difference between battery one and battery two, and then transmit it to the delay calculation module after proportional voltage reduction.

[0028] In some embodiments, the delay calculation module includes:

[0029] The voltage difference receiving unit is used to receive the voltage difference between battery one and battery two, and performs high-frequency filtering and electrical isolation functions during the receiving process.

[0030] The delay time calculation unit is used to calculate the switching delay time Δt based on the voltage difference between battery one and battery two, and send the switching delay time to the relay switching control module as the basis for the switching delay parameter.

[0031] In some embodiments, the delay calculation module is further configured to:

[0032] In response to a voltage difference ΔV being less than a preset threshold ΔVref, the switching delay time is reduced.

[0033] Thirdly, the present invention provides an apparatus comprising,

[0034] Memory;

[0035] processor;

[0036] as well as

[0037] Computer programs;

[0038] The computer program is stored in the memory and configured to be executed by the processor to implement the method described in the first aspect above.

[0039] Fourthly, the present invention provides a storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in the first aspect.

[0040] Beneficial Effects: The present invention provides a method, device, equipment, and storage medium for instantaneous switching overcurrent suppression of a charging pile with a dual-charger structure based on a delayed switching strategy. The charging pile first charges the power battery of the first electric vehicle via a first relay. After charging is completed, if the fully charged vehicle is not disconnected and the charging pile is connected to the second electric vehicle to be charged via a second relay, the battery voltage detection module detects the voltage values ​​of the power batteries of the two electric vehicles and performs voltage difference calculation. The obtained voltage difference is sent to the delayed calculation module via a wired connection. When the voltage difference is higher than a set threshold, the time lag between the activation of the second relay and the deactivation of the first relay is increased, and this delay time controls the triggering time of the relay switching control module. When the voltage difference is lower than the set threshold, the delay time is reduced to optimize the fast charging experience for the second electric vehicle user.

[0041] It has the following advantages: it solves the problem of instantaneous circulating current between the two sets of power batteries during the instantaneous switching of charging piles, and ensures the user's charging experience as long as the battery voltage difference does not exceed the threshold voltage.

[0042] Furthermore, the voltage difference and the relay switching delay interval can be quantitatively analyzed and set in practical applications, and the quantified indicators should also be within the protection scope of this invention. Attached Figure Description

[0043] Figure 1 This is a schematic diagram illustrating the charging fault principle of a charging pile with a dual-charger structure based on a delayed switching strategy.

[0044] Figure 2 This is a structural diagram of a charging pile with a dual-charger configuration based on a delayed switching strategy. Figure 2 Explanation of the names in the dashed box: 1 - Charging device module; 2 - Battery voltage acquisition module; 3 - Delay calculation module; 4 - Relay switching control module.

[0045] Figure 3 The battery state of charge and circulating current waveform during the charging period for electric vehicles that were charged before the delay switching strategy was adopted.

[0046] Figure 4The battery state of charge and circulating current waveform during the time period when the second charging vehicle, which did not adopt the delayed switching strategy, was connected to the charging pile.

[0047] Figure 5 The battery state of charge and circulating current waveform during the charging period of an electric vehicle that uses a delayed switching strategy to complete the charging task.

[0048] Figure 6 The battery state of charge and circulating current waveform during the time period when the second charging vehicle using the delayed switching strategy is connected to the charging pile;

[0049] Main symbol names: C1, C2, C3, C4 — relay parasitic capacitance; I c —Loop current; V1—Battery 1 voltage; V2—Battery 2 voltage; V acref —Voltage difference reference signal; E f —Delayed switching signal; S w1 S w2 —Relay switching control signal. Detailed Implementation

[0050] The present invention will be further described below with reference to the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and should not be used to limit the scope of protection of the present invention.

[0051] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0052] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0053] Example 1

[0054] Firstly, this embodiment provides a method for suppressing instantaneous switching overcurrent in a charging pile with a dual-charger structure based on a delayed switching strategy, including:

[0055] In response to the charging pile output side completing the charging of battery one through the first relay, the charging is switched to battery two through the second relay to start charging. Before the relay is switched, the voltage difference ΔV between battery one and battery two is obtained.

[0056] Based on the voltage difference between battery one and battery two, the switching delay time Δt is calculated, including: in response to the voltage difference ΔV being greater than the preset threshold ΔVref, the switching delay time is increased;

[0057] The first relay is controlled to disconnect, and the closing time of the second relay is selected according to the switching delay time to complete the charging.

[0058] In some embodiments, calculating the switching delay time Δt based on the voltage difference between battery one and battery two further includes:

[0059] In response to a voltage difference ΔV being less than a preset threshold ΔVref, the switching delay time is reduced.

[0060] In some embodiments, obtaining the voltage difference ΔV between battery one and battery two includes:

[0061] Obtain the voltage values ​​of battery one and battery two before the relay is switched on;

[0062] Calculate the voltage difference between battery one and battery two based on their voltage values ​​before the relay is switched on.

[0063] In some embodiments, the dual-charger structure of the present invention has the ability to provide charging services for two electric vehicles simultaneously. To ensure the safety and stability of the charging process, the present invention provides an instantaneous overcurrent suppression control strategy based on a delayed switching strategy.

[0064] In the charging pile of the present invention, the charging device module 1 generates a signal, and the battery voltage acquisition module 2 undertakes the task of data acquisition. After acquiring the voltage of battery one and battery two, the battery voltage acquisition module 2 calculates the voltage difference between the two sets of batteries.

[0065] The delay calculation module 3 calculates the delay time Δt based on the battery voltage difference and inputs the signal to the relay switching control module 4. During charging, to prevent a sudden increase in current, the relay needs to switch when the battery voltage difference reaches a certain value. The delay time Δt ensures that the relay switches at the appropriate time, thereby achieving the purpose of suppressing instantaneous overcurrent. In the relay switching control module 4, the relay on the input side of battery one is first disconnected, and then the closing time point is selected according to the delay time Δt to close the relay on the input side of battery two, completing the charging process. This achieves charging balance between the two batteries and avoids damage to the equipment and batteries caused by instantaneous overcurrent.

[0066] In summary, this invention provides an instantaneous overcurrent suppression control strategy based on a delayed switching strategy, which can effectively ensure the safety and stability of the charging process.

[0067] Working principle

[0068] This invention aims to solve the instantaneous overcurrent problem in existing technical solutions and provides a charging pile instantaneous switching overcurrent suppression method based on a delayed switching strategy to ensure a good user charging experience when the battery voltage difference does not exceed a threshold voltage. This invention is applicable to charging piles with a dual-charger structure and plays a crucial role in addressing the instantaneous circulating current problem between two sets of power batteries.

[0069] When implementing a transient overcurrent suppression control strategy based on a time-delay switching approach, the charging pile first charges the power battery of the first electric vehicle via a first relay. After the first vehicle completes charging, the charging pile connects to the second electric vehicle to be charged via a second relay. A battery voltage detection module detects the power battery voltages of both electric vehicles and calculates the voltage difference. This voltage difference is then sent to a time-delay calculation module via a wired connection. When the voltage difference exceeds a set threshold, the time lag between the second relay's activation and the first relay's activation is increased. This delay time controls the triggering time of the relay switching control module to reduce transient overcurrent. When the voltage difference falls below the set threshold, the delay time is reduced to optimize the fast charging experience for the second electric vehicle user.

[0070] In practical applications, the voltage difference and relay switching delay interval can be set through quantitative analysis to ensure the effectiveness and reliability of the invention. These quantitative indicators should also be within the scope of protection of this invention. In summary, the implementation of this invention can overcome the problems existing in the prior art and provide a more efficient, stable, and safer method for suppressing instantaneous switching overcurrent in charging piles.

[0071] Without a delayed switching strategy, the instantaneous switching of the relay can cause a large circulating current in the circuit, potentially damaging electric vehicle charging stations and other equipment. Experimental simulations are as follows... Figure 3 As shown, without a time-delay switching strategy, when the relay switch is instantaneously switched on, the first electric vehicle completes charging when it reaches 96.604%, and the first relay turns off because the first electric vehicle has completed its charging task, resulting in a momentary positive peak current of 3000 amps in the loop; Figure 4 As shown, when the second relay is turned on, the second electric vehicle connects to the charging pile with an initial charge capacity of 20%, and the loop generates... Figure 3 The waveform is the opposite of the instantaneous reverse spike of negative 3000 amps.

[0072] Employing a time-delay switching strategy can effectively suppress this overcurrent phenomenon and protect the normal operation of the circuit. The time-delay calculation module calculates the switching trigger interval between relays based on the current status of the charging pile and the charging demand of the electric vehicle, and then controls the relays to switch on and off at appropriate times to avoid generating large circulating currents. In this way, not only can the circuit equipment be protected, but the charging efficiency and stability of the electric vehicle charging pile can also be effectively improved. When the time-delay switching strategy is adopted, the following results are obtained: Figure 5 , 6 As shown in the waveform, after the delay calculation module has calculated the trigger interval of the relay switch, the relay switching control module switches at the appropriate time point. The current of battery 1 drops rapidly from 80A to 0, and the current of battery 2 rises rapidly from 0 to 120A, thereby achieving the purpose of instantaneous overcurrent suppression.

[0073] Example 2

[0074] Secondly, based on Embodiment 1, this embodiment provides a device for suppressing instantaneous switching overcurrent of a charging pile with a dual-charger structure based on a delayed switching strategy, comprising:

[0075] The battery voltage acquisition module is configured to: respond to the charging pile output side completing the charging of battery one via the first relay, and then switch to starting charging of battery two via the second relay. Before the relay switching...

[0076] Obtain the voltage difference ΔV between battery one and battery two;

[0077] The delay calculation module is configured to: calculate the switching delay time Δt based on the voltage difference between battery one and battery two, and send the switching delay time to the relay switching control module; wherein calculating the switching delay time Δt based on the voltage difference between battery one and battery two includes: increasing the switching delay time in response to the voltage difference ΔV being greater than a preset threshold ΔVref;

[0078] The relay switching control module is configured to: control the first relay to disconnect, and select the closing time of the second relay according to the switching delay time to complete the charging connection.

[0079] In some embodiments, the battery voltage acquisition module specifically includes:

[0080] The battery voltage acquisition unit is used to acquire the voltage values ​​of battery one and battery two before the relay is switched on;

[0081] The battery voltage difference calculation unit is used to calculate the voltage difference between battery one and battery two, and then transmit it to the delay calculation module after proportional voltage reduction.

[0082] In some embodiments, the delay calculation module includes:

[0083] The voltage difference receiving unit is used to receive the voltage difference between battery one and battery two, and performs high-frequency filtering and electrical isolation functions during the receiving process.

[0084] The delay time calculation unit is used to calculate the switching delay time Δt based on the voltage difference between battery one and battery two, and send the switching delay time to the relay switching control module as the basis for the switching delay parameter.

[0085] In some embodiments, the delay calculation module is further configured to:

[0086] In response to a voltage difference ΔV being less than a preset threshold ΔVref, the switching delay time is reduced.

[0087] Example 3

[0088] Thirdly, based on Embodiment 1, this embodiment provides a device, including,

[0089] Memory;

[0090] processor;

[0091] as well as

[0092] Computer programs;

[0093] The computer program is stored in the memory and configured to be executed by the processor to implement the method described in Embodiment 1.

[0094] Example 4

[0095] Fourthly, based on Embodiment 1, this embodiment provides a storage medium on which a computer program is stored, and when the computer program is executed by a processor, it implements the method described in Embodiment 1.

[0096] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0097] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0098] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0099] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0100] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for suppressing overcurrent during instantaneous switching of a charging pile with a dual-charger structure based on a delayed switching strategy, characterized in that, include: In response to the charging pile output side completing the charging of battery one through the first relay, the charging is switched to battery two through the second relay to start charging. Before the relay is switched, the voltage difference ΔV between battery one and battery two is obtained. Based on the voltage difference between battery one and battery two, calculate the switching delay time Δt, including: in response to the voltage difference ΔV exceeding a preset threshold ΔV ref Increase the casting delay time; The first relay is controlled to disconnect, and the closing time of the second relay is selected according to the switching delay time to complete the charging.

2. The instantaneous switching overcurrent suppression method for a charging pile with a dual-charger structure based on a delayed switching strategy according to claim 1, characterized in that, The switching delay time Δt is calculated based on the voltage difference between battery one and battery two, and also includes: In response to a voltage difference ΔV being less than a preset threshold ΔV ref This reduces the switching delay time.

3. The instantaneous switching overcurrent suppression method for a charging pile with a dual-charger structure based on a delayed switching strategy according to claim 1, characterized in that, The step of obtaining the voltage difference ΔV between battery one and battery two includes: Obtain the voltage values ​​of battery one and battery two before the relay is switched on; Calculate the voltage difference between battery one and battery two based on their voltage values ​​before the relay is switched on.

4. The instantaneous switching overcurrent suppression method for a charging pile with a dual-charger structure based on a delayed switching strategy according to claim 1, characterized in that, Specifically, the following steps are included: Step 1: Detect the terminal voltage of battery one and battery two, and calculate the voltage difference between battery one and battery two; Step 2: The voltage difference at the feedback terminal is sent to the delay calculation module to calculate the delay time; Step 3: The first relay on the battery input side is disconnected; Step 4: The second relay on the input side of battery 2 selects the closing time point according to the delay time to complete the charging connection, thereby reducing the instantaneous overcurrent caused by the parasitic capacitance of the relays during the rapid switching process of the two sets of battery input side relays, and achieving the purpose of protecting the charging device and the battery.

5. A system for suppressing overcurrent during instantaneous switching of a charging pile with a dual-charger structure based on a delayed switching strategy, characterized in that: include: The battery voltage acquisition module is configured to: in response to the charging pile output side completing the charging of battery one through the first relay, switch to battery two to start charging through the second relay, and acquire the voltage difference ΔV between battery one and battery two before the relay is switched on; The delay calculation module is configured to: calculate the switching delay time Δt based on the voltage difference between battery one and battery two, and send the switching delay time to the relay switching control module; wherein calculating the switching delay time Δt based on the voltage difference between battery one and battery two includes: responding to a voltage difference ΔV greater than a preset threshold ΔV ref Increase the casting delay time; The relay switching control module is configured to: control the first relay to disconnect, and select the closing time of the second relay according to the switching delay time to complete the charging connection.

6. The instantaneous switching overcurrent suppression system for a charging pile with a dual-charger structure based on a delayed switching strategy according to claim 5, characterized in that, The battery voltage acquisition module specifically includes: The battery voltage acquisition unit is used to acquire the voltage values ​​of battery one and battery two before the relay is switched on; The battery voltage difference calculation unit is used to calculate the voltage difference between battery one and battery two, and then transmit it to the delay calculation module after proportional voltage reduction.

7. The instantaneous switching overcurrent suppression system for a charging pile with a dual-charger structure based on a delayed switching strategy according to claim 5, characterized in that, The delay calculation module includes: The voltage difference receiving unit is used to receive the voltage difference between battery one and battery two, and performs high-frequency filtering and electrical isolation functions during the receiving process. The delay time calculation unit is used to calculate the switching delay time Δt based on the voltage difference between battery one and battery two, and send the switching delay time to the relay switching control module as the basis for the switching delay parameter.

8. The instantaneous switching overcurrent suppression system for a charging pile with a dual-charger structure based on a delayed switching strategy according to claim 5, characterized in that, The delay calculation module is also used for: In response to a voltage difference ΔV being less than a preset threshold ΔV ref This reduces the switching delay time.

9. A device, characterized in that, include: Memory; processor; as well as Computer programs; The computer program is stored in the memory and configured to be executed by the processor to implement the method as described in any one of claims 1 to 4.

10. A storage medium, characterized in that, It stores a computer program thereon, which, when executed by a processor, implements the method described in any one of claims 1 to 4.

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