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

Abstract

The invention discloses a three-phase load balance control method based on a charging pile group, relates to the technical field of charging pile group control, solves the problem that the original three-phase control process is not accurate, and fully manifests the adaptability advantage by flexibly adjusting the current supply of each phase according to the current requirements at different moments. 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 operation is reduced, and equipment loss is reduced; when the current demand is increased, a method of gradually increasing the current and synchronously coordinating each phase is ingeniously adopted, three-phase balance is orderly realized, each charging pile can obtain stable and sufficient electric power, the overall charging efficiency is improved, the waiting time of a vehicle due to insufficient electric power is shortened, and in the scene that the current demand is reduced, the current is controlled to be gradually reduced by reverse thinking; three-phase balance is ensured in the whole process, and equipment impact or power grid fluctuation caused by sudden reduction of current is avoided.

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] The application with publication number CN117239789B discloses a three-phase balance control method and device for a pile group, wherein the pile group includes a plurality of three-phase charging piles, each of which performs three-phase charging or single-phase charging on a charging object, and the method includes the following steps: obtaining the current of each phase of the three-phase alternating current powering the pile group; determining the first phase, the second phase and the third phase of the three-phase alternating current according to the magnitude of the current of each phase of the three-phase alternating current; generating a phase change control instruction when the difference between the current of the first phase and the current of the second phase is greater than a preset threshold; after the three-phase charging pile to be charged receives the charging instruction, the first phase and the third phase of the three-phase charging pile to be charged are controlled to change phases according to the phase change 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. The invention can automatically realize the three-phase load balance of the 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 deficiencies in the prior art, 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 by the following technical solution: A three-phase load balancing control method based on a charging pile group 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 adjusted quickly 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. The specific sub-steps are:

[0008] S11, calibrate the real-time monitored current of each phase to Li-k , where i represents different phases and k represents different moments. The three sets of real-time current 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 directly perform a quick balance adjustment;

[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 moments, where N is a preset value, and 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. From the several groups of change data identified by the corresponding phase, lock the minimum value and the maximum value, 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 +Maximum value;

[0010] S13, confirming the current interval associated with each different phase at the next moment in turn, and randomly selecting a current value from each different current interval, and performing variance processing on the randomly selected current value to confirm the associated variance, and confirming from the confirmed groups of associated variances whether all associated variances satisfy: all associated variances < Y1, if satisfied, continue monitoring, if not satisfied, generate a control signal;

[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 the current of each phase at the subsequent moment is confirmed and evenly distributed. The specific sub-steps are:

[0012] S21, confirming the generation time of the control signal, and confirming the current associated with each phase corresponding to the generation time, calibrating the confirmed current of each phase as L1, L2 and L3, identifying the current value at the middle position from L1, L2 and L3, calibrating the phase associated with this current value as the middle phase, and calibrating 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 calibrating the current values ​​of the other two phases, and sorting the calibrated current values ​​in ascending order of value, and confirming 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 the current demand 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 position of the sorting calibration sequence, so that its output current is gradually increased. During the increase process, the current value of the first position of the sorting calibration sequence increases synchronously. When the current value of the first position increases to be consistent with the current value of the second position, the current value of the first position and the current value of the second position are synchronously controlled to increase synchronously, and the current value increased in each increase process is consistent;

[0017] When the current values ​​of the first and second digits increase to be consistent with 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 is changed 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.

[0018] When the current demand of the pile group at a later moment is lower than the current demand 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 the synchronous decrease. When the current value of the third position decreases to be consistent with 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 synchronously dropped 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.

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

[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 associated phase with max is determined, and the supply current of the associated phase to the charging pile is selected from a plurality of supply currents, and the charging pile associated with the supply current is represented by D i The associated phase corresponding to min supplies current to complete 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 prior art, it has the following beneficial effects:

[0025] The present invention can keenly capture the subtle imbalance trend of the three-phase current of the pile group by real-time monitoring of the three-phase current, applying variance processing and combining the prediction of past current change data. Compared with the traditional method that only relies on rough threshold judgment, this multi-level recognition system has greatly improved the accuracy;

[0026] In 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 to reduce unnecessary operations and reduce equipment losses; 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, the current is controlled to gradually decrease with reverse thinking to ensure three-phase balance throughout the process and avoid equipment shock or grid fluctuations caused by a sudden drop in current. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work 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 adjusted quickly based on the specific value change of each phase current, and generate a control signal or a quick adjustment signal according to the identification result. Specifically, when the pile group is changing normally, 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 be unevenly distributed by the system, which will cause a large difference in the current of each phase, resulting in an imbalance.

[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. The three sets of real-time current 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, which means 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 its current change data = the current data of the next moment - the current data of the previous moment (the next moment and the previous moment here belong to adjacent moments, the next moment is the next group of moments of the previous moment, and the previous moment is the previous group of moments of 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 +Maximum value;

[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 several sets of associated variances, it is confirmed whether all associated variances meet the following conditions: all associated variances < Y1, if satisfied, continuous monitoring is performed, if not satisfied, a control signal is generated (the control signal here represents that an unbalanced situation may occur at the next moment, then the corresponding control signal is directly generated for current control, so as to avoid an unbalanced current in 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, and 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 confirmed, and evenly distributed to complete the balance control process, wherein the specific sub-steps of even distribution are:

[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 of value, and confirm the sorting calibration sequence, for example: the three-phase currents are proposed to be 5A, 10A and 15A respectively, then the current value in the middle is 10A, calibrate 10A to 0, that is, reduce 10A, then the currents of the front and rear phases are synchronously calibrated and changed, and the changed current values ​​are -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 the current demand 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 position of the sorting calibration sequence, so that its output current is gradually increased. During the increase process, the current value of the first position of the sorting calibration sequence increases synchronously. When the current value of the first position increases to be consistent with the current value of the second position, the current value of the first position and the current value of the second position are synchronously controlled to increase synchronously, and the current value increased in each increase process is consistent;

[0041] When the current values ​​of the first and second digits increase to be consistent with 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 calibration sequence is changed 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 (for example: originally {-5, 0, 5}, after the corresponding adjustment process, the corresponding subsequent moment is higher than the previous moment, and the higher value is 5A, then the phase associated with -5 is controlled to supply current first, and after control, the sequence is adjusted to {0, 0, 5}, then the subsequent moments are regulated according to {0, 0, 5});

[0042] When the current demand of the pile group at a later moment is lower than the current demand 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 the synchronous decrease. When the current value of the third position decreases to be consistent with 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 synchronously dropped 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.

[0045] Specifically, in the specific balance execution control process, the control process of increasing the current value and the control process of reducing the current value will often be interspersed with control, and in each group of control processes, the determined sequence is adjusted in real time according to the corresponding control parameters, and the subsequent control process performs balance control according to the adjusted sequence, so as to complete 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 (it may be caused by the intervention of a large-power demand vehicle, which leads to such a situation, so rapid adjustment is required). Confirm the supply current of each phase when the rapid adjustment signal is generated. 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 of control are as follows:

[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 associated phase with max is determined, and the supply current of the associated phase to the charging pile is selected from a plurality of supply currents, and the charging pile associated with the supply current is represented by D i The associated phase corresponding to min 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, the processing process is executed again to complete the corresponding supply current adjustment process, and 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 satisfying 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 rather than to limit it. 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 adjusted quickly based on the specific value change of each phase current, and generate a control signal or a quick adjustment signal according to the identification result; 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, and based on the correlation difference of the current value of each phase at the previous moment, the distribution logic of the current of each phase at the subsequent moment is confirmed and evenly distributed; Step 3: Based on the generated fast adjustment signal, confirm the supply current of each phase corresponding to the generation of this fast 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 1, the specific sub-steps for identifying whether the pile group needs to be balanced controlled are: S11, calibrate the real-time monitored current of each phase to L i-k , where i represents different phases and k represents different moments. The three sets of real-time current 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 directly perform a quick balance adjustment.

3. The three-phase load balancing control method based on a charging pile group according to claim 2 is characterized in that: In step 1, the specific sub-step of identifying whether the pile group needs to be balanced controlled also includes: 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, and 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. From the several groups of change data identified by the corresponding phase, lock the minimum value and the maximum value, 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 +Maximum value; S13. Confirm the current interval associated with each different phase at the next moment in turn, and randomly select a current value from each different current interval, and perform variance processing on the randomly selected current value to confirm the associated variance, and confirm from the confirmed groups of associated variances whether all associated variances meet the condition that all associated variances are less than Y1. If so, continue monitoring; if not, generate a control signal.

4. 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, confirming the generation time of the control signal, and confirming the current associated with each phase corresponding to the generation time, calibrating the confirmed current of each phase as L1, L2 and L3, identifying the current value at the middle position from L1, L2 and L3, calibrating the phase associated with this current value as the middle phase, and calibrating 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 calibrating the current values ​​of the other two phases, and sorting the calibrated current values ​​in ascending order of value, and confirming 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 a later moment is the same as the current demand at a previous moment, no processing is performed and the current supply state of the three phases remains unchanged.

5. The three-phase load balancing control method based on a charging pile group according to claim 4 is characterized in that: In the 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 the current demand 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 position of the sorting calibration sequence, so that its output current is gradually increased. During the increase process, the current value of the first position of the sorting calibration sequence increases synchronously. When the current value of the first position increases to be consistent with the current value of the second position, the current value of the first position and the current value of the second position are synchronously controlled to increase synchronously, and the current value increased in each increase process is 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.

6. The three-phase load balancing control method based on a charging pile group according to claim 4 is characterized in that: In the 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 the current demand 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 the synchronous decrease. When the current value of the third position decreases to be consistent with 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 also dropped 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.

7. 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 of 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 associated phase with max is determined, and the supply current of the associated phase to the charging pile is selected from a plurality of supply currents, and the charging pile associated with the supply current is represented by D i The associated phase corresponding to min supplies current to complete the adjustment process of the supply current.

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