Three-phase load balancing control method based on charging pile group

Abstract

The present invention discloses a three-phase load balancing control method based on a charging pile group. The present invention relates to the field of charging pile group control technology, and solves the problem that the original three-phase control process is not accurate. The present invention fully demonstrates its adaptability advantage by flexibly adjusting the current supply of each phase according to the current demand at different times; when the current demand at a later moment is the same as that at a previous moment, the current stable power supply state is maintained, unnecessary operations are reduced, and equipment loss is reduced; in the face of rising current demand, a method of gradually increasing the current and synchronously coordinating the phases is cleverly adopted to achieve three-phase balance in an orderly manner, ensuring that each charging pile can obtain stable and sufficient power, improving the overall charging efficiency, and reducing the waiting time of vehicles due to insufficient power. In the scenario where the current demand decreases, the current is controlled to decrease gradually by reverse thinking, ensuring three-phase balance throughout the process, and avoiding equipment impact or power grid fluctuation caused by a sudden drop in current.

Description

Technical Field

[0001] The present invention relates to the technical field of charging pile group control, and in particular to a three-phase load balancing control method based on a charging pile group. Background Art

[0002] A charging pile cluster refers to a collection of multiple charging piles that are centrally arranged and uniformly managed. It is designed to meet the charging needs of multiple electric vehicles in a specific area and has become a key component in the construction of modern electric vehicle infrastructure.

[0003] Application Publication No. CN117239789B discloses a method and device for controlling three-phase balancing of a charging pile group. The charging pile group comprises multiple three-phase charging piles, each of which performs three-phase or single-phase charging on charging objects. The method comprises the following steps: obtaining the current of each phase of the three-phase AC power supplying the charging pile group; determining the first, second, and third phases of the three-phase AC power supply based on the magnitude of the current of each phase of the three-phase AC power supply; generating a phase switching control instruction when the difference between the current of the first phase and the current of the second phase exceeds a preset threshold; and upon receiving the charging instruction, controlling the first and third phases of the three-phase charging pile to be charged to switch phases according to the phase switching control instruction, so that the input end of the first phase is connected to the output end of the third phase, and the input end of the third phase is connected to the output end of the first phase. This invention can automatically achieve three-phase load balancing in a three-phase AC charging station.

[0004] During the three-phase load balancing control process, the charging pile group performs real-time adjustment and control based on the current supply corresponding to each phase. However, in the actual control process, the current of each phase is only evenly distributed according to the subsequent demand current, and the subsequent current needs to be supplied continuously. The current of each phase is not monitored in real time to identify the numerical differences between the corresponding phases, so as to complete a more accurate control process and make the three phases more balanced. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the present invention provides a three-phase load balancing control method based on a charging pile group, which solves the problem that the original three-phase control process is not accurate.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: Based on the three-phase load balancing control method of the charging pile group, the method includes the following steps:

[0007] Step 1: Monitor the three-phase current of the charging pile group in real time, and identify whether the pile group needs to be balanced or quickly adjusted based on the specific value changes of each phase current. Based on the identification results, generate a control signal or a quick adjustment signal. The specific sub-steps are as follows:

[0008] S11, calibrate the real-time monitored current of each phase to Li-k , where i represents different phases and k represents different moments, and the three sets of real-time currents L corresponding to the three phases are i-k Perform variance processing to confirm the associated variance GF k , if GF k <Y1, then execute step S12 for reanalysis. If GF k ≥Y1, a quick adjustment signal is generated and step 3 is executed to perform a quick balance adjustment directly;

[0009] S12, based on the current L associated with each phase at the current moment i-k , identify the change data generated by the corresponding phase in the past N groups of time, where N is a preset value, and the change data is the current change data between adjacent moments, the current change data = the current data of the next moment - the current data of the previous moment, from the several groups of change data identified by the corresponding phase, lock the minimum and maximum values, based on the current L associated with the corresponding phase i-k , predict the current interval [Qmin, Qmax] generated at the next set of moments, where Qmin = L i-k + minimum value, where Qmax = L i-k +max;

[0010] S13, confirming the current interval associated with each different phase at the next moment in sequence, and randomly selecting a current value from each different current interval, performing variance processing on the randomly selected current value to confirm the associated variance, and confirming whether all associated variances from the confirmed groups of associated variances meet the condition that all associated variances are less than Y1. If so, continuous monitoring is performed; if not, a control signal is generated.

[0011] Step 2: Based on the control signal generated by the corresponding pile group, the current value associated with each phase of the pile group is regulated. Based on the correlation difference of the current value of each phase at the previous moment, the distribution logic of each phase current at the subsequent moment is determined and evenly distributed. The specific sub-steps are:

[0012] S21. Confirm the generation time of the control signal and confirm the current associated with each phase corresponding to the generation time. Calibrate the confirmed current of each phase as L1, L2, and L3. Identify the current value at the middle position among L1, L2, and L3. Calibrate the phase associated with this current value as the middle phase. Calibrate the current value of the middle phase to 0. Based on the change pattern of the middle phase current value during this calibration process, synchronously calibrate the current values ​​of the other two phases. Sorting the calibrated current values ​​in ascending order of value to confirm the sorting calibration sequence.

[0013] S22. Based on the confirmed sorting calibration sequence, control the current supply at subsequent moments:

[0014] When the current demand of the pile group at the next moment is the same as the current demand at the previous moment, no processing is performed and the current supply state of the three phases remains unchanged;

[0015] When the current demand of the pile group at a later moment is higher than that at a previous moment, current control is performed according to the following control process:

[0016] Prioritize the current output control of the phase associated with the first phase of the sorting calibration sequence, so that its output current gradually increases. During the increase process, the current value of the first phase of the sorting calibration sequence increases synchronously. When the current value of the first phase increases to the same as the current value of the second phase, the current values ​​of the first phase and the second phase are synchronously controlled to increase synchronously, and the current values ​​increased in each increase process are consistent.

[0017] When the current values ​​of the first and second digits increase to the same value as the current value of the third digit, the current values ​​of the first, second, and third digits are increased synchronously to complete the current balance control process associated with each phase. In the real-time adjustment control process, the sorting and calibration sequence is changed in real time according to the adjustment process. When the current values ​​of the three phases in the sorting and calibration sequence are the same, the balance control process is stopped.

[0018] When the current demand of the pile group at a later moment is lower than that at a previous moment, current control is performed according to the following control process:

[0019] Prioritize the current output control of the phase associated with the third position of the sorting calibration sequence, so that its output current gradually decreases. During the decrease process, the current value of the third position of the sorting calibration sequence follows and decreases synchronously. When the current value of the third position decreases to the same level as the current value of the second position, the current value of the third position and the current value of the second position are synchronously controlled to decrease synchronously, and the current values ​​decreased in each decrease process are consistent;

[0020] When the current values ​​of the third and second digits drop to the same level as the current value of the first digit, the current values ​​of the first, second, and third digits are caused to drop synchronously, completing the current balance control process associated with each phase. In the real-time adjustment control process, the sorting and calibration sequence is changed in real time according to the adjustment process. When the current values ​​of the three phases in the sorting and calibration sequence are the same, the balance control process is stopped.

[0021] Step 3: Based on the generated rapid adjustment signal, determine the supply current of each phase corresponding to the generation of the rapid adjustment signal, and based on the numerical difference between the supply currents of each phase, readjust the charging pile supplied by each phase, and control the supply current of each phase to achieve a balanced state between each phase. The specific sub-steps are as follows:

[0022] S31, calibrate the supply current of each phase at the time when the fast adjustment signal is generated as D i , where i represents different phases, the supply current D of three different phases i Select D i max and D i min, and determine the charging pile supplied by the corresponding associated phase, using: GX=(D i max-D i min)÷2 to confirm the associated value GX;

[0023] S32, from D i The charging pile supplied by the max associated phase is determined, and the supply current of the associated phase to the charging pile is selected from a plurality of supply currents, which is closest to the associated value GX, and the charging pile associated with this supply current is represented by D i The associated phase corresponding to min supplies current, completing the adjustment process of the supply current.

[0024] The present invention provides a three-phase load balancing control method based on a charging pile group. Compared with the existing technology, it has the following advantages:

[0025] This invention monitors three-phase current in real time, applies variance processing, and combines predictions based on past current change data to keenly detect subtle imbalance trends in the three-phase current of a pile group. Compared to traditional methods that rely solely on rough threshold judgments, this multi-level recognition system significantly improves accuracy.

[0026] During the balancing control process, the current supply of each phase is flexibly adjusted according to the current demand at different times, fully demonstrating its adaptability advantage; when the current demand at the next moment is the same as that at the previous moment, the current stable power supply state is maintained, unnecessary operations are reduced, and equipment loss is reduced; in the face of rising current demand, the method of gradually increasing the current and synchronously coordinating the phases is cleverly adopted to achieve three-phase balance in an orderly manner, ensuring that each charging pile can obtain stable and sufficient power, improving the overall charging efficiency, and reducing the waiting time of vehicles due to insufficient power. In the scenario where the current demand decreases, reverse thinking is used to control the current to gradually decrease, ensuring three-phase balance throughout the process, and avoiding equipment impact or power grid fluctuations due to sudden current drops. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] See also Figure 1 The present application provides a three-phase load balancing control method based on a charging pile group, comprising the following steps:

[0030] Step 1: Monitor the three-phase current of the charging pile group in real time, and identify whether the pile group needs to be balanced or quickly adjusted based on the specific value changes of each phase current, and generate a control signal or a quick adjustment signal based on the identification result. Specifically, when the pile group undergoes normal changes, the current of each phase changes normally. During the change process, if the current of each phase changes with the intervention of the corresponding charging pile, the current of each phase will differ greatly due to the uneven distribution of the system, and an imbalance will occur.

[0031] The specific sub-steps for identifying whether the pile group needs to be balanced are:

[0032] S11, calibrate the real-time monitored current of each phase to L i-k , where i represents different phases and k represents different moments, and the three sets of real-time currents L corresponding to the three phases are i-k Perform variance processing to confirm the associated variance GF k , if GF k <Y1, then execute step S12 for reanalysis. If GF k ≥Y1, a fast adjustment signal is generated and step 3 is executed to directly perform a fast balance adjustment, indicating that the three-phase current of the current pile group needs to be balanced. Y1 is a preset value, and its specific value is determined by the operator based on experience;

[0033] S12, based on the current L associated with each phase at the current moment i-k , identify the change data generated by the corresponding phase in the past N groups of moments, where N is a preset value, at least 30, and its specific value is determined by the operator based on experience. The change data is the current change data between adjacent moments, and the current change data = the current data of the next moment - the current data of the previous moment (the next moment and the previous moment are adjacent moments, the next moment is the next group of moments after the previous moment, and the previous moment is the previous group of moments before the next moment). From the several groups of change data identified by the corresponding phase, lock the minimum value and the maximum value (the minimum value is generally less than 0), based on the current L associated with the corresponding phase i-k, predict the current interval [Qmin, Qmax] generated at the next set of moments, where Qmin = L i-k + minimum value, where Qmax = L i-k +max;

[0034] S13, the current interval associated with each different phase at the next moment is confirmed in turn, and a current value is randomly selected from each different current interval, and the randomly selected current value is subjected to variance processing (in each random selection process, only one set of current values ​​can be selected for the current interval of the corresponding phase), the associated variance is confirmed, and from the confirmed sets of associated variances, it is confirmed whether all associated variances meet the following conditions: all associated variances < Y1. If so, continuous monitoring is performed; if not, a control signal is generated (the control signal here represents a situation where an imbalance may occur at the next moment, so a corresponding control signal is directly generated for current control to avoid an imbalance in the current of the corresponding pile group);

[0035] Step 2: Based on the control signal generated by the corresponding pile group, the current value associated with each phase of the pile group is regulated. Based on the correlation difference of the current value of each phase at the previous moment, the distribution logic of each phase current at the subsequent moment is determined and evenly distributed to complete the balance control process. The specific sub-steps of even distribution are as follows:

[0036] S21. Confirm the generation time of the control signal, and confirm the current associated with each phase corresponding to the generation time, calibrate the confirmed current of each phase as L1, L2, and L3, identify the current value at the middle position from L1, L2, and L3, calibrate the phase associated with this current value as the middle phase, and calibrate the current value of the middle phase to 0. Based on the change form of the middle phase current value during this calibration process, synchronously calibrate the current values ​​of the other two phases, and sort the calibrated current values ​​in ascending order to confirm the sorting calibration sequence. For example: if the three-phase currents are 5A, 10A, and 15A respectively, then the current value in the middle is 10A. Calibrate 10A to 0, that is, reduce it by 10A, then the currents of the front and rear phases will synchronously follow the calibration change, and the changed current values ​​will be -5A, 0A, and 5A;

[0037] S22. Based on the confirmed sorting calibration sequence, control the current supply at subsequent moments:

[0038] When the current demand of the pile group at the next moment is the same as the current demand at the previous moment, no processing is performed and the current supply state of the three phases remains unchanged;

[0039] When the current demand of the pile group at a later moment is higher than that at a previous moment, current control is performed according to the following control process:

[0040] Prioritize the current output control of the phase associated with the first phase of the sorting calibration sequence, so that its output current gradually increases. During the increase process, the current value of the first phase of the sorting calibration sequence increases synchronously. When the current value of the first phase increases to the same as the current value of the second phase, the current values ​​of the first phase and the second phase are synchronously controlled to increase synchronously, and the current values ​​increased in each increase process are consistent.

[0041] When the current values ​​of the first and second digits increase to the same value as the current value of the third digit, the current values ​​of the first, second, and third digits are increased synchronously, completing the current balance control process associated with each phase. In the real-time adjustment control process, the sorting and calibration sequence changes in real time according to the adjustment process. When the current values ​​of the three phases in the sorting and calibration sequence are the same, the balance control process is stopped (for example, if the current values ​​are originally {-5, 0, 5}, and after the corresponding adjustment process, the corresponding subsequent moment is higher than the previous moment by 5A, then the current supply of the phase associated with -5 is prioritized. After control, the current sequence is adjusted to {0, 0, 5}, and the subsequent moments are controlled according to {0, 0, 5}).

[0042] When the current demand of the pile group at a later moment is lower than that at a previous moment, current control is performed according to the following control process:

[0043] Prioritize the current output control of the phase associated with the third position of the sorting calibration sequence, so that its output current gradually decreases. During the decrease process, the current value of the third position of the sorting calibration sequence follows and decreases synchronously. When the current value of the third position decreases to the same level as the current value of the second position, the current value of the third position and the current value of the second position are synchronously controlled to decrease synchronously, and the current values ​​decreased in each decrease process are consistent;

[0044] When the current values ​​of the third and second digits drop to the same level as the current value of the first digit, the current values ​​of the first, second, and third digits are caused to drop synchronously, completing the current balance control process associated with each phase. In the real-time adjustment control process, the sorting and calibration sequence is changed in real time according to the adjustment process. When the current values ​​of the three phases in the sorting and calibration sequence are the same, the balance control process is stopped.

[0045] Specifically, during the specific balance execution control process, the control process of increasing the current value and the control process of decreasing the current value are often interspersed with each other. In each group of control processes, the determined sequence is adjusted in real time according to the corresponding control parameters. The subsequent control processes perform balance control according to the adjusted sequence, thereby completing the overall balance control process of the three phases.

[0046] Step 3: Based on the generated rapid adjustment signal, the three-phase current of the charging pile group has completely shown an unbalanced state (this may be caused by the intervention of a large-power demand vehicle, so rapid adjustment is required). Confirm the supply current of each phase when this rapid adjustment signal is generated. Based on the numerical difference between the supply currents of each phase, readjust the charging piles supplied by each phase, and control the supply current of each phase to achieve a balanced state between each phase. The specific sub-steps of the control are:

[0047] S31, calibrate the supply current of each phase at the time when the fast adjustment signal is generated as D i , where i represents different phases, the supply current D of three different phases i Select D i max and D i min, and determine the charging pile supplied by the corresponding associated phase, using: GX=(D i max-D i min)÷2 to confirm the associated value GX;

[0048] S32, from D i The charging pile supplied by the max associated phase is determined, and the supply current of the associated phase to the charging pile is selected from a plurality of supply currents, which is closest to the associated value GX, and the charging pile associated with this supply current is represented by D i min corresponding associated phase supplies current to complete the supply current adjustment process. Since the corresponding step one has been in the real-time monitoring process, if the corresponding fast adjustment signal still appears, this processing process is executed again to complete the corresponding supply current adjustment process. The corresponding normal supply charging pile is selected from the phase with the maximum supply current, so that it supplies current with the corresponding minimum supply power, thereby not only sharing the supply pressure of the maximum supply phase, but also fully meeting the balance control process of each phase current.

[0049] Some of the data in the above formulas are dimensionless and numerically calculated. Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0050] The above embodiments are only used to illustrate the technical method of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A three-phase load balancing control method based on a charging pile group, characterized in that: The following steps are involved: Step 1: Monitor the three-phase current of the charging pile group in real time, and identify whether the pile group needs to be balanced or quickly adjusted based on the specific value changes of each phase current. Based on the identification results, generate a control signal or a quick adjustment signal. The specific sub-steps are as follows: S11, calibrate the real-time monitored current of each phase to L i-k , where i represents different phases and k represents different moments, and the three sets of real-time currents L corresponding to the three phases are i-k Perform variance processing to confirm the associated variance GF k , if GF k <Y1, then execute step S12 for reanalysis. If GF k ≥Y1, a quick adjustment signal is generated and step 3 is executed to perform a quick balance adjustment directly; S12, based on the current L associated with each phase at the current moment i-k , identify the change data generated by the corresponding phase in the past N groups of time, where N is a preset value, and the change data is the current change data between adjacent moments, the current change data = the current data of the next moment - the current data of the previous moment, from the several groups of change data identified by the corresponding phase, lock the minimum and maximum values, based on the current L associated with the corresponding phase i-k , predict the current interval [Qmin, Qmax] generated at the next set of moments, where Qmin = L i-k + minimum value, where Qmax = L i-k +max; S13, confirming the current interval associated with each different phase at the next moment in sequence, and randomly selecting a current value from each different current interval, performing variance processing on the randomly selected current value to confirm the associated variance, and confirming whether all associated variances from the confirmed groups of associated variances meet the condition that all associated variances are less than Y1. If so, continuous monitoring is performed; if not, a control signal is generated. Step 2: Based on the control signal generated by the corresponding pile group, the current value associated with each phase of the pile group is regulated. Based on the correlation difference of the current value of each phase at the previous moment, the distribution logic of each phase current at the subsequent moment is determined and evenly distributed; Step 3: Based on the generated rapid adjustment signal, confirm the supply current of each phase corresponding to the generation of this rapid adjustment signal, and based on the numerical difference between the supply currents of each phase, readjust the charging pile supplied by each phase, and control the supply current of each phase to achieve a balanced state between each phase.

2. The three-phase load balancing control method based on a charging pile group according to claim 1 is characterized in that: In step 2, the specific sub-steps for uniform distribution are: S21. Confirm the generation time of the control signal and confirm the current associated with each phase corresponding to the generation time. Calibrate the confirmed current of each phase as L1, L2, and L3. Identify the current value at the middle position among L1, L2, and L3. Calibrate the phase associated with this current value as the middle phase. Calibrate the current value of the middle phase to 0. Based on the change pattern of the middle phase current value during this calibration process, synchronously calibrate the current values ​​of the other two phases. Sorting the calibrated current values ​​in ascending order of value to confirm the sorting calibration sequence. S22. Based on the confirmed sorting calibration sequence, control the current supply at subsequent moments: When the current demand of the pile group at the next moment is the same as the current demand at the previous moment, no processing is performed and the current supply state of the three phases remains unchanged.

3. The three-phase load balancing control method based on a charging pile group according to claim 2 is characterized in that: In step S22, controlling the current supply at subsequent moments further includes: When the current demand of the pile group at a later moment is higher than that at a previous moment, current control is performed according to the following control process: Prioritize the current output control of the phase associated with the first phase of the sorting calibration sequence, so that its output current gradually increases. During the increase process, the current value of the first phase of the sorting calibration sequence increases synchronously. When the current value of the first phase increases to the same as the current value of the second phase, the current values ​​of the first phase and the second phase are synchronously controlled to increase synchronously, and the current values ​​increased in each increase process are consistent. When the current values ​​of the first and second digits increase to the same level as the current value of the third digit, the current values ​​of the first, second, and third digits are increased synchronously to complete the balance control process of the current associated with each phase. In the real-time adjustment control process, the sorting calibration sequence changes in real time according to the adjustment process. When the current values ​​of the three phases in the sorting calibration sequence are the same, the balance control process is stopped.

4. The three-phase load balancing control method based on a charging pile group according to claim 3 is characterized in that: In step S22, controlling the current supply at subsequent moments further includes: When the current demand of the pile group at a later moment is lower than that at a previous moment, current control is performed according to the following control process: Prioritize the current output control of the phase associated with the third position of the sorting calibration sequence, so that its output current gradually decreases. During the decrease process, the current value of the third position of the sorting calibration sequence follows and decreases synchronously. When the current value of the third position decreases to the same level as the current value of the second position, the current value of the third position and the current value of the second position are synchronously controlled to decrease synchronously, and the current values ​​decreased in each decrease process are consistent; When the current values ​​of the third and second digits drop to the same level as the current value of the first digit, the current values ​​of the first, second and third digits are caused to drop synchronously to complete the balance control process of the current associated with each phase. In the real-time adjustment control process, the sorting calibration sequence changes in real time according to the adjustment process. When the current values ​​of the three phases in the sorting calibration sequence are the same, the balance control process is stopped.

5. The three-phase load balancing control method based on a charging pile group according to claim 1 is characterized in that: In step 3, the specific sub-steps for controlling the supply current of each phase are: S31, calibrate the supply current of each phase at the time when the fast adjustment signal is generated as D i , where i represents different phases, the supply current D of three different phases i Select D i max and D i min, and determine the charging pile supplied by the corresponding associated phase, using: GX=(D i max-D i min)÷2 to confirm the associated value GX; S32, from D i The charging pile supplied by the max associated phase is determined, and the supply current of the associated phase to the charging pile is selected from a plurality of supply currents, which is closest to the associated value GX, and the charging pile associated with this supply current is represented by D i The associated phase corresponding to min supplies current, completing the adjustment process of the supply current.

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