Three-phase unbalance adjustment method, system and storage medium for AC charging stack

Abstract

The present invention relates to the field of charging technology, and specifically to a three-phase imbalance regulation method, system and storage medium of an AC charging stack, wherein the AC charging stack comprises a transformer, a main control board and a plurality of charging terminals; the method comprises: in the power supply process of the AC charging stack, determining the three-phase imbalance of the transformer based on charging data; if it is determined that the three-phase imbalance is greater than an imbalance threshold, dynamically adjusting the charging terminals connected to the three phases of the transformer according to the charging data, so as to adjust the three-phase imbalance of the transformer to be lower than the imbalance threshold; if it is determined that the three-phase imbalance of the transformer is lower than the imbalance threshold, determining a switching control strategy based on the required voltage type of the vehicle charging port, and controlling the charging terminal connected to the vehicle to supply power to the vehicle charging port according to the switching control strategy; the present invention realizes effective control of the three-phase imbalance by monitoring the charging data of the three phases during the charging process and dynamically adjusting the charging strategy.

Description

Technical Field

[0001] The present invention relates to the field of charging technology, and in particular to a three-phase unbalance adjustment method, system and storage medium for an AC charging stack. Background Art

[0002] There are more and more new energy vehicles. In order to meet the charging needs of new energy vehicles, many AC charging piles (AC piles for short) will be built in parks and residential destinations. However, there are currently two problems that are difficult to solve. The first is the problem of three-phase imbalance. When charging, the output line of a single-phase AC pile is only connected to one live wire. When the single-phase AC pile is used unbalanced, the single-phase AC pile cannot adapt to the three-phase imbalance; when the three-phase AC pile outputs single-phase AC power, it will also cause three-phase imbalance. When discharging, the use of the AC pile will also be unbalanced, which will also cause three-phase imbalance. The three-phase imbalance problem will lead to a decline in the quality of the power grid, affecting the charging efficiency and the life of the equipment.

[0003] Therefore, it is necessary to study the three-phase imbalance problem of the AC charging stack and provide a solution that can effectively control the three-phase imbalance. Summary of the invention

[0004] In view of this, the purpose of the embodiments of the present invention is to provide a three-phase imbalance regulation method, system and storage medium for an AC charging stack, which can effectively control the three-phase imbalance by dynamically adjusting the charging strategy through real-time monitoring of the three-phase charging data during the charging process.

[0005] On the one hand, an embodiment of the present invention provides a three-phase unbalance adjustment method for an AC charging stack, wherein the AC charging stack includes a transformer, a main control board, and a plurality of charging terminals, wherein the charging terminals include a plurality of single-phase AC piles and a plurality of three-phase AC piles, wherein the main control board is respectively connected to each of the charging terminals in communication, and the transformer is respectively connected to each of the charging terminals in electrical communication;

[0006] The method comprises the following steps:

[0007] S100, during the power supply process of the AC charging stack, obtaining charging data of the AC charging stack, determining a three-phase imbalance of the transformer based on the charging data, and comparing the three-phase imbalance with a preset imbalance threshold;

[0008] S200, if it is determined that the three-phase imbalance is greater than the imbalance threshold, dynamically adjusting the charging terminals connected to the three phases of the transformer according to the charging data to adjust the three-phase imbalance of the transformer to be lower than the imbalance threshold;

[0009] S300, if it is determined that the three-phase imbalance of the transformer is lower than the imbalance threshold, then in response to the vehicle's charging request instruction, the required voltage type of the vehicle's charging port is obtained, and a switching control strategy is determined based on the required voltage type, and the charging terminal connected to the vehicle is controlled according to the switching control strategy to supply power to the vehicle's charging port; wherein the required voltage type includes single-phase demand and three-phase demand; the switching control strategy includes allocating the three phases of the transformer in turn to the charging terminal providing single-phase demand, and allocating the three phases of the transformer to the three-phase AC pile providing three-phase demand in a switching order.

[0010] Further, in S100, the acquiring charging data of the AC charging stack and determining the three-phase imbalance of the transformer based on the charging data includes:

[0011] S110, acquiring charging data of the AC charging pile every other detection cycle, the charging data including: average output power of the three phases of the transformer in the most recent detection cycle, and the switching phase of each single-phase AC pile and the switching time of the phase;

[0012] S120, obtaining the capacity of the transformer, and calculating the three-phase imbalance of the transformer in a most recent detection cycle based on the capacity of the transformer and the average output power of the three phases of the transformer in a most recent detection cycle.

[0013] Further, in S110, the average output power of the three phases of the transformer in the most recent detection cycle is determined by:

[0014] S111, for each phase of the transformer, obtaining a single-phase AC pile switched on and off in the most recent detection cycle of the phase;

[0015] S112, obtaining the switching time of each of the single-phase AC piles, dividing the detection period into multiple sub-periods according to the switching time, and determining the output power of the phase in each sub-period;

[0016] S113, averaging the output power of the phase in each of the sub-periods to obtain the average output power of the phase in the most recent detection period.

[0017] Further, in S200, dynamically adjusting the charging terminals connected to the three phases of the transformer according to the charging data to adjust the three-phase imbalance of the transformer to be lower than the imbalance threshold includes:

[0018] S210, obtaining the output power of the three phases of the transformer in each sub-cycle in the most recent detection cycle, and calculating the unbalance index of the transformer in the most recent detection cycle based on the capacity of the transformer and the output power in each sub-cycle;

[0019] S220, if it is determined that the imbalance index exceeds the index threshold, then determine the high-power phase and the low-power phase in the most recent sub-cycle, find each single-phase AC pile connected to the high-power phase, obtain the switching time and power supply power of each single-phase AC pile, and determine the power impact of the single-phase AC pile based on the switching time and power supply power of the single-phase AC pile; wherein the high-power phase is the phase with the largest average output power among the three phases of the transformer, and the low-power phase is the phase with the smallest average output power among the three phases of the transformer;

[0020] S230, determining a single-phase AC pile whose power supply power is less than the power regulation threshold from each single-phase AC pile connected to the high-power phase as the single-phase AC pile to be switched; arranging each single-phase AC pile to be switched in descending order according to the power influence from high to low, selecting one single-phase AC pile to be switched in sequence, and switching the single-phase AC pile to be switched from the high-power phase to the low-power phase; wherein the power regulation threshold is the sum of the three-phase imbalance of the transformer and the imbalance threshold;

[0021] S240, determining whether the three-phase imbalance of the transformer is lower than the imbalance threshold, if not, executing S250; if yes, executing S270;

[0022] S250, determining whether there are more than one single-phase AC pile connected to the high-power phase, if so, executing S230; if not, stopping switching the single-phase AC pile connected to the high-power phase to the low-power phase, and when detecting a switching request sent by a charging terminal providing a single-phase demand, allocating the low-power phase to the charging terminal, and then executing S260;

[0023] S260, determining an adjustment coefficient based on the three-phase imbalance of each sub-cycle of the transformer in the most recent detection cycle, and updating the detection cycle based on the adjustment coefficient; wherein the magnitude of the adjustment coefficient is negatively correlated with the three-phase imbalance of each sub-cycle;

[0024] S270: Determine whether the imbalance index of the transformer is lower than the imbalance threshold, and end.

[0025] Further, in S210, the obtaining of the output power of the three phases of the transformer in each sub-cycle in the most recent detection cycle, and the calculation of the unbalance index of the transformer in the most recent detection cycle based on the capacity of the transformer and the output power in each sub-cycle, include:

[0026] S211, numbering each sub-cycle in the most recent detection cycle in ascending order from far to near the current time, and normalizing the number of each sub-cycle to serve as the weight of each sub-cycle;

[0027] S212, calculating the three-phase imbalance of each sub-cycle based on the capacity of the transformer and the output power in each sub-cycle, averaging the three-phase imbalance of each sub-cycle, and obtaining the average value of the three-phase imbalance in the most recent detection cycle;

[0028] S213, calculating the unbalance index of the transformer in the most recent detection cycle according to the following formula:

[0029]

[0030] Where D1 is the unbalance index of the transformer in the most recent detection cycle, d i is the three-phase unbalance degree of the ith sub-cycle, d avg is the mean value of the three-phase imbalance within the detection period, d th is the imbalance threshold, α i is the weight of the i-th sub-cycle, i=1,2,...,n, n is the total number of sub-cycles in the last detection cycle, max() means finding the maximum value, λ1 and λ2 are adjustment coefficients, and satisfy 0<λ1<1, 0<λ2<1, λ1+λ2=1.

[0031] Further, in S220, the power influence of the single-phase AC pile is calculated by the following formula:

[0032]

[0033] Among them, E j is the power impact of the jth single-phase AC pile, t j is the switching time of the jth single-phase AC pile, P j is the power supply of the jth single-phase AC pile, t max is the maximum value of the switching time of each single-phase AC pile connected to the high-power phase, P max is the maximum value of the switching time of each single-phase AC pile connected to the high-power phase, exp represents a natural exponential function, ω1 and ω2 are adjustment coefficients, and satisfy 0<ω1<1, 0<ω2<1, ω1+ω2=1.

[0034] Further, in S260, determining the adjustment coefficient based on the three-phase imbalance of each sub-cycle of the transformer in the most recent detection cycle, and updating the detection cycle based on the adjustment coefficient, includes:

[0035] S261, obtaining the three-phase imbalance degree of the transformer in each sub-cycle;

[0036] S262, comparing the three-phase unbalance degree in each of the sub-cycles with the first tolerance threshold, obtaining the number of times the three-phase unbalance degree of the transformer exceeds the first tolerance threshold in the most recent detection cycle, and recording it as a first cumulative number;

[0037] S263, determining whether the first cumulative number is greater than 0, if so, executing S264, if not, executing S265;

[0038] S264, setting the adjustment coefficient to k1 / 2 m , update the detection period to k1·T1 / 2 m ; Wherein, k1 is a preset proportional coefficient, 0<k1<1, m is the first cumulative number, and T1 is the duration of the most recent detection cycle;

[0039] S265, comparing the three-phase unbalance degree in each of the sub-cycles with the second tolerance threshold, obtaining the number of times the three-phase unbalance degree of the transformer is lower than the second tolerance threshold in the most recent detection cycle, and recording it as a second cumulative number; wherein the second tolerance threshold is less than the first tolerance threshold, and the first tolerance threshold is less than the unbalance degree threshold;

[0040] S266, setting the adjustment coefficient to k2·2 n , update the detection period to k2·T1·2 n ; Wherein, k2 is a preset proportional coefficient, 0.5<k2<1, and n is the second cumulative number.

[0041] On the other hand, an embodiment of the present invention provides a three-phase unbalanced regulation system for an AC charging stack, comprising:

[0042] at least one processor;

[0043] at least one memory for storing at least one program;

[0044] When the at least one program is executed by the at least one processor, the at least one processor implements the above method.

[0045] On the other hand, an embodiment of the present invention provides a computer-readable storage medium, in which a program executable by a processor is stored. When the program executable by the processor is executed by the processor, it is used to perform the above method.

[0046] The embodiments of the present invention include the following beneficial effects: the embodiment first determines the three-phase imbalance of the transformer based on the charging data, and compares the three-phase imbalance with a preset imbalance threshold; determines whether the AC charging pile currently has three-phase imbalance, and if the three-phase imbalance is greater than the imbalance threshold, dynamically adjusts the charging terminals connected to the three phases of the transformer according to the charging data, thereby adjusting the three-phase imbalance of the transformer to below the imbalance threshold; if it is determined that the three-phase imbalance of the transformer is lower than the imbalance threshold, determines the switching control strategy based on the required voltage type, and controls the charging terminal connected to the vehicle to supply power to the vehicle charging port according to the switching control strategy; by allocating the three phases of the transformer to the charging terminal providing single-phase demand in turn according to the switching order, and allocating the three phases of the transformer to the three-phase AC pile providing three-phase demand, the three-phase power can be distributed in an orderly manner, and effective control of the three-phase imbalance can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0048] Figure 1 It is a flow chart of a three-phase unbalance adjustment method of an AC charging stack provided by an embodiment of the present invention;

[0049] Figure 2 is a structural block diagram of an AC charging stack provided by an embodiment of the present invention;

[0050] Figure 3 It is a structural block diagram of a three-phase unbalanced regulation system for an AC charging stack provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0052] It should be noted that although the functional charging modules are divided in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described can be performed in a different order than the charging module division in the device or the order in the flowchart. The terms "first", "second", etc. in the specification, claims and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0054] like Figure 1 and Figure 2 As shown, Figure 1 A three-phase unbalance adjustment method for an AC charging stack provided in an embodiment of the present invention, the AC charging stack comprises a transformer, a main control board and a plurality of charging terminals, the charging terminals comprise a plurality of single-phase AC piles and a plurality of three-phase AC piles, the main control board is respectively connected to each of the charging terminals for communication, and the transformer is respectively connected to each of the charging terminals for electrical communication;

[0055] Specifically, the single-phase AC pile includes a single-phase phase-changing switch, and the three-phase AC pile includes a three-phase phase-changing switch; the single-phase AC pile and the three-phase AC pile both include a terminal control board and a charging gun; the main control board is communicated and connected with each terminal control board in the charging terminal through a switch, and the terminal control board in the single-phase AC pile is communicated and connected with the single-phase phase-changing switch and the charging gun in the single-phase AC pile where it is located, and the terminal control board in the three-phase AC pile is communicated and connected with the three-phase phase-changing switch and the charging gun in the three-phase AC pile where it is located; the corresponding terminals of the single-phase phase-changing switch are respectively connected to one of the A phase, B phase, and C phase and the N line on the output side of the transformer, and the corresponding terminals of the three-phase phase-changing switch are respectively connected to the A phase, B phase, C phase and the N line.

[0056] The method comprises the following steps:

[0057] S100, during the power supply process of the AC charging stack, obtaining charging data of the AC charging stack, determining a three-phase imbalance of the transformer based on the charging data, and comparing the three-phase imbalance with a preset imbalance threshold;

[0058] S200, if it is determined that the three-phase imbalance is greater than the imbalance threshold, dynamically adjusting the charging terminals connected to the three phases of the transformer according to the charging data to adjust the three-phase imbalance of the transformer to be lower than the imbalance threshold;

[0059] S300, if it is determined that the three-phase imbalance of the transformer is lower than the imbalance threshold, then in response to the vehicle's charging request instruction, the required voltage type of the vehicle's charging port is obtained, and a switching control strategy is determined based on the required voltage type, and the charging terminal connected to the vehicle is controlled according to the switching control strategy to supply power to the vehicle's charging port; wherein the required voltage type includes single-phase demand and three-phase demand; the switching control strategy includes allocating the three phases of the transformer in turn to the charging terminal providing single-phase demand, and allocating the three phases of the transformer to the three-phase AC pile providing three-phase demand in a switching order.

[0060] refer to Figure 2 When charging the vehicle, the main control board uses a switch to communicate with each terminal control board through Ethernet. The charging terminals numbered 01 to M are set as single-phase AC piles, and the charging terminals numbered M+1 to M+N are set as three-phase AC piles. When charging with a single-phase AC pile, the main control board sends charging instructions to the terminal control board in the order of charging time, requiring the corresponding single-phase phase-changing switches to be switched according to the logic of A phase, B phase, and C phase cycle, such as 01 control board switches A phase, 02 control board switches B phase, 03 control board switches C phase, 04 control board switches A phase, and so on.

[0061] When charging with a three-phase AC pile, the terminal control board will detect whether the vehicle's required voltage type is single-phase or three-phase when interacting with the vehicle. If it is a three-phase demand, KM1 and KM2 will be energized, and the three-phase phase-changing switch will be switched to phase A. If it is a single-phase demand, KM1 and KM2 will be disconnected, and the three-phase phase-changing switch will follow the switching logic of the single-phase phase-changing switch of the single-phase AC pile.

[0062] The three-phase imbalance adjustment method using the switching control strategy can only ensure that the power distribution at the beginning of charging is as balanced as possible, but the user's behavior of ending charging is random, so it cannot be guaranteed that the three-phase is balanced at any time. At this time, it is necessary to monitor the three-phase imbalance of the transformer in real time during the charging process, and set the imbalance threshold to 15%; then when the three-phase imbalance is greater than 15%, it is necessary to change the switching logic, control the three-phase imbalance within 15%, and then switch according to the switching control strategy.

[0063] According to the formula: three-phase unbalance degree = |maximum power - minimum power| / transformer capacity*100%; the allowable range of three-phase unbalance degree is ≤15%. Among them, maximum power = {P A , P B , P C} MAX ; Minimum power = {P A , P B , P C} MIN ; If: P A=40kW; P B =80kW; P C =100kW; transformer capacity is 315kVA; then three-phase unbalance = (100000-40000) / 315000*100%≈19%; that is, the three-phase unbalance is greater than 15%, and the three-phase power distribution needs to be adjusted. It should be noted that if the three-phase unbalance = unbalance threshold, a comparison is made after waiting for a period of time.

[0064] In the embodiment provided by the present invention, the main control board is connected to the cloud platform, and all charging terminals can be remotely controlled. The main control board communicates with all terminal control boards via Ethernet, and the Ethernet communication between the main control board and the charging terminal is performed through a switch, which is not limited by the CAN communication distance; the AC charging pile of the present invention has an independent transformer, and the main control board monitors the status of the transformer; the charging terminal of the present invention can be either a single-phase AC pile or a three-phase AC pile, and the output power is 3.5kW, 7kW, 11kW, 21kW, and 42kW, which greatly enriches the product types. When it is at the peak of electricity consumption, while ensuring the balance of the three phases, the single-phase AC pile and the three-phase AC pile are executed with a power reduction output instruction. Reduce the current value from 63A to 32A or 16A; reduce the voltage value from 380V to 220V; if it still cannot meet the demand, the output of the newly switched charging terminal can be prohibited, or the output can be delayed.

[0065] As an improvement of the above embodiment, in S100, acquiring charging data of the AC charging stack and determining the three-phase imbalance of the transformer based on the charging data includes:

[0066] S110, acquiring charging data of the AC charging pile every other detection cycle, the charging data including: average output power of the three phases of the transformer in the most recent detection cycle, and the switching phase of each single-phase AC pile and the switching time of the phase;

[0067] It should be noted that this embodiment intermittently calculates the three-phase imbalance of the transformer in the most recent detection cycle according to the detection cycle, which can effectively monitor and timely adjust the three-phase power distribution, thereby reducing the three-phase imbalance.

[0068] S120, obtaining the capacity of the transformer, and calculating the three-phase imbalance of the transformer in a most recent detection cycle based on the capacity of the transformer and the average output power of the three phases of the transformer in a most recent detection cycle.

[0069] Specifically, the maximum value of the average output powers of the three phases of the transformer in the most recent detection cycle is taken as the maximum average output power, and the minimum value of the average output powers of the three phases of the transformer in the most recent detection cycle is taken as the minimum average output power; then, the three-phase imbalance of the transformer in the most recent detection cycle = |maximum average output power-minimum average output power| / capacity of the transformer*100%.

[0070] It should be noted that if the three-phase imbalance calculated roughly is greater than the imbalance threshold, it means that the transformer must have a three-phase imbalance problem, which needs to be treated in subsequent steps. If the three-phase imbalance calculated roughly is less than or equal to the imbalance threshold, it means that the transformer may have a three-phase imbalance problem in some time periods, but it is still within a tolerable level and can be automatically adjusted through the subsequent switching control strategy, so no treatment is performed.

[0071] As an improvement of the above embodiment, in S110, the average output power of the three phases of the transformer in the most recent detection cycle is determined by the following method:

[0072] S111, for each phase of the transformer, obtaining a single-phase AC pile switched on and off in the most recent detection cycle of the phase;

[0073] S112, obtaining the switching time of each of the single-phase AC piles, dividing the detection period into multiple sub-periods according to the switching time, and determining the output power of the phase in each sub-period;

[0074] S113, averaging the output power of the phase in each of the sub-periods to obtain the average output power of the phase in the most recent detection period.

[0075] It should be noted that the average output power calculated in this embodiment is an overall estimate of the output power of the three phases in the most recent detection cycle, so as to facilitate the subsequent preliminary statistics of the three-phase imbalance of the transformer in the most recent detection cycle.

[0076] As an improvement of the above embodiment, in S200, dynamically adjusting the charging terminals connected to the three phases of the transformer according to the charging data to adjust the three-phase imbalance of the transformer to be lower than the imbalance threshold includes:

[0077] S210, obtaining the output power of the three phases of the transformer in each sub-cycle in the most recent detection cycle, and calculating the unbalance index of the transformer in the most recent detection cycle based on the capacity of the transformer and the output power in each sub-cycle;

[0078] It should be noted that the imbalance index reflects the degree of change of the three-phase imbalance of the transformer in each sub-cycle within the most recent detection cycle. The larger the imbalance index, the more drastic the change of the three-phase imbalance in each sub-cycle. Conversely, the three-phase imbalance in each sub-cycle changes relatively slowly.

[0079] S220, if it is determined that the imbalance index exceeds the index threshold, then determine the high-power phase and the low-power phase in the most recent sub-cycle, find each single-phase AC pile connected to the high-power phase, obtain the switching time and power supply power of each single-phase AC pile, and determine the power impact of the single-phase AC pile based on the switching time and power supply power of the single-phase AC pile; wherein the high-power phase is the phase with the largest average output power among the three phases of the transformer, and the low-power phase is the phase with the smallest average output power among the three phases of the transformer;

[0080] It should be noted that the index threshold is pre-set to determine the size of the imbalance index. For example, the index threshold is set between 1% and 15%, and the optimal value of the imbalance index is 0. If the imbalance index exceeds the index threshold, it means that the charging terminal is frequently switched on or off in a short period of time. The high-power phase should be optimized and adjusted in time by extending the switching time of the single-phase AC pile to reduce its power output and increasing the power of the low-power phase accordingly, so as to achieve the purpose of quickly reducing the imbalance.

[0081] In addition, the shorter the switching time of the single-phase AC pile, the longer the expected duration of subsequent charging, and the longer the power stability can be maintained; the longer the switching time of the single-phase AC pile, the shorter the expected time to the end of charging, and the greater the possibility of power instability in the short term; it can be seen that the switching time of the single-phase AC pile affects the power change frequency of the phase; selecting a single-phase AC pile with a shorter switching time for switching can avoid three-phase instability caused by frequent switching; the power supply power of the single-phase AC pile is used to meet the charging needs of the vehicle. The greater the power supply power, the greater the impact on the power change of the phase, and the more obvious the improvement of the three-phase imbalance; combining the switching time and power supply power of the single-phase AC pile to determine the power influence, affecting the power change size and frequency of the phase, can maintain a relatively stable improvement on the three-phase imbalance for a long time; avoid the problem of unclear and unstable improvement of three-phase imbalance.

[0082] S230, determining a single-phase AC pile whose power supply power is less than the power regulation threshold from each single-phase AC pile connected to the high-power phase as the single-phase AC pile to be switched; arranging each single-phase AC pile to be switched in descending order according to the power influence from high to low, selecting one single-phase AC pile to be switched in sequence, and switching the single-phase AC pile to be switched from the high-power phase to the low-power phase; wherein the power regulation threshold is the sum of the three-phase imbalance of the transformer and the imbalance threshold;

[0083] It should be noted that the value of the three-phase imbalance is an absolute value. Taking the three-phase imbalance equal to 20% and the imbalance threshold equal to 15% as an example, the minimum difference is |20%-15%|=5%, and the maximum difference is |-20%-15%|=35%. Therefore, the minimum difference is the absolute value of the difference between the three-phase imbalance of the transformer and the imbalance threshold, and the maximum difference is the sum of the three-phase imbalance of the transformer and the imbalance threshold; the maximum difference is the maximum power allowed for phase adjustment, which is used as the power adjustment threshold.

[0084] S240, determining whether the three-phase imbalance of the transformer is lower than the imbalance threshold, if not, executing S250; if yes, executing S270;

[0085] S250, determining whether there are more than one single-phase AC pile connected to the high-power phase, if so, executing S230; if not, stopping switching the single-phase AC pile connected to the high-power phase to the low-power phase, and when detecting a switching request sent by a charging terminal providing a single-phase demand, allocating the low-power phase to the charging terminal, and then executing S260;

[0086] It should be noted that the single-phase AC piles connected to the high-power phase are switched to the low-power phase one by one in the order of switching time from near to far; if there is only one single-phase AC pile left connected to the high-power phase, and the three-phase balance cannot be achieved by adjusting the single-phase AC pile, consider waiting for a period of time, and after detecting a newly switched single-phase AC pile or a three-phase AC pile that provides single-phase demand, switch the single-phase AC pile or the three-phase AC pile that provides single-phase demand to the low-power phase, and then determine whether the three-phase balance is achieved.

[0087] S260, determining an adjustment coefficient based on the three-phase imbalance of each sub-cycle of the transformer in the most recent detection cycle, and updating the detection cycle based on the adjustment coefficient; wherein the magnitude of the adjustment coefficient is negatively correlated with the three-phase imbalance of each sub-cycle;

[0088] S270: Determine whether the imbalance index of the transformer is lower than the imbalance threshold, and end.

[0089] In this embodiment, through real-time monitoring and dynamic adjustment, it is ensured that the power distribution of each phase AC pile is more reasonable and adapts to the power balance under different charging requirements.

[0090] As an improvement of the above embodiment, in S210, the obtaining of the output power of the three phases of the transformer in each sub-cycle in the most recent detection cycle, and the calculation of the unbalance index of the transformer in the most recent detection cycle based on the capacity of the transformer and the output power in each sub-cycle, include:

[0091] S211, numbering each sub-cycle in the most recent detection cycle in ascending order from far to near the current time, and normalizing the number of each sub-cycle to serve as the weight of each sub-cycle;

[0092] S212, calculating the three-phase imbalance of each sub-cycle based on the capacity of the transformer and the output power in each sub-cycle, averaging the three-phase imbalance of each sub-cycle, and obtaining the average value of the three-phase imbalance in the most recent detection cycle;

[0093] S213, calculating the unbalance index of the transformer in the most recent detection cycle according to the following formula:

[0094]

[0095] Where D1 is the unbalance index of the transformer in the most recent detection cycle, d i is the three-phase unbalance degree of the ith sub-cycle, d avg is the mean value of the three-phase imbalance within the detection period, d th is the imbalance threshold, α i is the weight of the i-th sub-cycle, i=1,2,...,n, n is the total number of sub-cycles in the last detection cycle, max() means finding the maximum value, λ1 and λ2 are adjustment coefficients, and satisfy 0<λ1<1, 0<λ2<1, λ1+λ2=1.

[0096] In this embodiment, combined with the maximum difference between the three-phase imbalance of all sub-cycles and the mean, taking into account the extreme case, combined with the sum of the differences between the three-phase imbalance of each sub-cycle and the imbalance threshold, the output power in each sub-cycle is weighted, the closer to the current time, the greater the weight, and the overall difference of each sub-cycle is reflected in a targeted manner; by adjusting the ratio of the maximum difference and the overall difference allocated by the adjustment coefficient, the imbalance condition of the transformer in the detection cycle can be more effectively grasped, and the degree of change of the three-phase imbalance of the sub-cycle can be comprehensively reflected, so as to make timely adjustments to ensure the stable operation of the power system. The value range of D1 is (0, 1).

[0097] As an improvement of the above embodiment, in S220, the power influence of the single-phase AC pile is calculated by the following formula:

[0098]

[0099] Among them, E j is the power impact of the jth single-phase AC pile, t j is the switching time of the jth single-phase AC pile, P j is the power supply of the jth single-phase AC pile, t max is the maximum value of the switching time of each single-phase AC pile connected to the high-power phase, P max is the maximum value of the switching time of each single-phase AC pile connected to the high-power phase, exp represents a natural exponential function, ω1 and ω2 are adjustment coefficients, and satisfy 0<ω1<1, 0<ω2<1, ω1+ω2=1.

[0100] It should be noted that the shorter the switching time and the greater the power supply power, the greater the power impact; if the switching time increases or the power supply power decreases, the power impact will decrease accordingly; the longer the switching time and the smaller the power supply power, the smaller the power impact; through the power impact calculation formula provided in this embodiment, the switching time and power supply power of the single-phase AC pile are comprehensively considered, which can take into account the three-phase imbalance improvement effect and stability.

[0101] As an improvement of the above embodiment, in S260, determining the adjustment coefficient based on the three-phase imbalance of the transformer in each sub-cycle in the most recent detection cycle, and updating the detection cycle based on the adjustment coefficient, includes:

[0102] S261, obtaining the three-phase imbalance degree of the transformer in each sub-cycle;

[0103] S262, comparing the three-phase unbalance degree in each of the sub-cycles with the first tolerance threshold, obtaining the number of times the three-phase unbalance degree of the transformer exceeds the first tolerance threshold in the most recent detection cycle, and recording it as a first cumulative number;

[0104] S263, determining whether the first cumulative number is greater than 0, if so, executing S264, if not, executing S265;

[0105] S264, setting the adjustment coefficient to k1 / 2 m , update the detection period to k1·T1 / 2 m ; Wherein, k1 is a preset proportional coefficient, 0<k1<1, m is the first cumulative number, and T1 is the duration of the most recent detection cycle;

[0106] S265, comparing the three-phase unbalance degree in each of the sub-cycles with the second tolerance threshold, obtaining the number of times the three-phase unbalance degree of the transformer is lower than the second tolerance threshold in the most recent detection cycle, and recording it as a second cumulative number; wherein the second tolerance threshold is less than the first tolerance threshold, and the first tolerance threshold is less than the unbalance degree threshold;

[0107] S266, setting the adjustment coefficient to k2·2 n , update the detection period to k2·T1·2 n ; Wherein, k2 is a preset proportional coefficient, 0.5<k2<1, and n is the second cumulative number.

[0108] It should be noted that, within the detection cycle, the more times the imbalance index exceeds the first tolerance threshold, the more frequently the imbalance index changes, and the more frequently the charging terminal is switched on and off, requiring faster dynamic switching of the charging terminal, thereby reducing the duration of the detection cycle; by dynamically adjusting the detection cycle, it is possible to adapt to the current usage of the charging terminal and achieve three-phase balance in a timely manner.

[0109] Under the premise that the unbalance index in each sub-cycle is lower than the first tolerance threshold, if the unbalance index is lower than the second tolerance threshold for a longer time, it means that the transformer is relatively stable. At this time, appropriately extending the detection cycle will help reduce the adjustment frequency and reduce unnecessary calculations and energy consumption. At the same time, this is also conducive to improving the overall operating efficiency and reliability of the system and ensuring stable power supply to the charging terminal.

[0110] See also Figure 3 The embodiment of the present invention provides a three-phase unbalanced regulation system for an AC charging stack, comprising:

[0111] at least one processor;

[0112] at least one memory for storing at least one program;

[0113] When the at least one program is executed by the at least one processor, the at least one processor implements the above method.

[0114] It can be seen that the contents of the above method embodiments are all applicable to the present system embodiments, the functions specifically implemented by the present system embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0115] In addition, the embodiment of the present application also discloses a computer program product or a computer program, and the computer program product or the computer program is stored in a computer-readable storage medium. The processor of the computer device can read the computer program from the computer-readable storage medium, and the processor executes the computer program, so that the computer device performs the above method. Similarly, the contents in the above method embodiment are all applicable to the storage medium embodiment, and the functions specifically implemented by the storage medium embodiment are the same as those in the above method embodiment, and the beneficial effects achieved are also the same as those achieved by the above method embodiment.

[0116] It will be appreciated by those skilled in the art that all or some of the systems in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or transient medium). As is known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0117] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

Claims

1. A three-phase unbalance adjustment method for an AC charging stack, characterized in that: The AC charging stack includes a transformer, a main control board and a plurality of charging terminals, the charging terminals include a plurality of single-phase AC piles and a plurality of three-phase AC piles, the main control board is respectively connected to each of the charging terminals for communication, and the transformer is respectively connected to each of the charging terminals for electrical communication; The method comprises the following steps: S100, during the power supply process of the AC charging stack, obtaining charging data of the AC charging stack, determining a three-phase imbalance of the transformer based on the charging data, and comparing the three-phase imbalance with a preset imbalance threshold; S200, if it is determined that the three-phase imbalance is greater than the imbalance threshold, dynamically adjusting the charging terminals connected to the three phases of the transformer according to the charging data to adjust the three-phase imbalance of the transformer to be lower than the imbalance threshold; S300, if it is determined that the three-phase imbalance of the transformer is lower than the imbalance threshold, then in response to the charging request instruction of the vehicle, the required voltage type of the vehicle charging port is obtained, and a switching control strategy is determined based on the required voltage type, and the charging terminal connected to the vehicle is controlled according to the switching control strategy to supply power to the vehicle charging port; wherein the required voltage type includes single-phase demand and three-phase demand; the switching control strategy includes allocating the three phases of the transformer to the charging terminal providing the single-phase demand in turn according to the switching sequence, and allocating the three phases of the transformer to the three-phase AC pile providing the three-phase demand; S200 specifically includes: S210, obtaining the output power of the three phases of the transformer in each sub-cycle in the most recent detection cycle, and calculating the unbalance index of the transformer in the most recent detection cycle based on the capacity of the transformer and the output power in each sub-cycle; S220, if it is determined that the imbalance index exceeds the index threshold, then determine the high-power phase and the low-power phase in the most recent sub-cycle, find each single-phase AC pile connected to the high-power phase, obtain the switching time and power supply power of each single-phase AC pile, and determine the power impact of the single-phase AC pile based on the switching time and power supply power of the single-phase AC pile; wherein the high-power phase is the phase with the largest average output power among the three phases of the transformer, and the low-power phase is the phase with the smallest average output power among the three phases of the transformer; S230, determining a single-phase AC pile whose power supply power is less than the power regulation threshold from each single-phase AC pile connected to the high-power phase as the single-phase AC pile to be switched; arranging each single-phase AC pile to be switched in descending order according to the power influence from high to low, selecting one single-phase AC pile to be switched in sequence, and switching the single-phase AC pile to be switched from the high-power phase to the low-power phase; wherein the power regulation threshold is the sum of the three-phase imbalance of the transformer and the imbalance threshold; S240, determining whether the three-phase imbalance of the transformer is lower than the imbalance threshold, if not, executing S250; if yes, executing S270; S250, determining whether there are more than one single-phase AC pile connected to the high-power phase, if so, executing S230; if not, stopping switching the single-phase AC pile connected to the high-power phase to the low-power phase, and when detecting a switching request sent by a charging terminal providing a single-phase demand, allocating the low-power phase to the charging terminal, and then executing S260; S260, determining an adjustment coefficient based on the three-phase imbalance of each sub-cycle of the transformer in the most recent detection cycle, and updating the detection cycle based on the adjustment coefficient; wherein the magnitude of the adjustment coefficient is negatively correlated with the three-phase imbalance of each sub-cycle; S270, determining that the imbalance index of the transformer is lower than the imbalance threshold, and ending.

2. The method according to claim 1, characterized in that In S100, the acquiring charging data of the AC charging stack and determining the three-phase imbalance of the transformer based on the charging data includes: S110, acquiring charging data of the AC charging pile every other detection cycle, the charging data including: average output power of the three phases of the transformer in the most recent detection cycle, and the switching phase of each single-phase AC pile and the switching time of the phase; S120, obtaining the capacity of the transformer, and calculating the three-phase imbalance of the transformer in a most recent detection cycle based on the capacity of the transformer and the average output power of the three phases of the transformer in a most recent detection cycle.

3. The method according to claim 2, characterized in that In S110, the average output power of the three phases of the transformer in the most recent detection cycle is determined by: S111, for each phase of the transformer, obtaining a single-phase AC pile switched on and off in the most recent detection cycle of the phase; S112, obtaining the switching time of each of the single-phase AC piles, dividing the detection period into multiple sub-periods according to the switching time, and determining the output power of the phase in each sub-period; S113, averaging the output power of the phase in each of the sub-periods to obtain the average output power of the phase in the most recent detection period.

4. The method according to claim 1, characterized in that: In S210, the step of obtaining the output power of the three phases of the transformer in each sub-cycle in the most recent detection cycle, and calculating the unbalance index of the transformer in the most recent detection cycle based on the capacity of the transformer and the output power in each sub-cycle, includes: S211, numbering each sub-cycle in the most recent detection cycle in ascending order from far to near the current time, and normalizing the number of each sub-cycle to serve as the weight of each sub-cycle; S212, calculating the three-phase imbalance of each sub-cycle based on the capacity of the transformer and the output power in each sub-cycle, averaging the three-phase imbalance of each sub-cycle, and obtaining the average value of the three-phase imbalance in the most recent detection cycle; S213, calculating the unbalance index of the transformer in the most recent detection cycle according to the following formula: ； Where D1 is the unbalance index of the transformer in the most recent detection cycle, d i is the three-phase unbalance degree of the ith sub-cycle, d avg is the mean value of the three-phase imbalance within the detection period, d th is the imbalance threshold, α i is the weight of the i-th sub-cycle, i=1,2,...,n, n is the total number of sub-cycles in the last detection cycle, max() means finding the maximum value, λ1 and λ2 are adjustment coefficients, and satisfy 0<λ1<1, 0<λ2<1, λ1+λ2=1.

5. The method according to claim 1, characterized in that In S220, the power influence of the single-phase AC pile is calculated by the following formula: ； Among them, E j is the power impact of the jth single-phase AC pile, t j is the switching time of the jth single-phase AC pile, P j is the power supply of the jth single-phase AC pile, t max is the maximum value of the switching time of each single-phase AC pile connected to the high-power phase, P max is the maximum value of the switching time of each single-phase AC pile connected to the high-power phase, exp represents a natural exponential function, ω1 and ω2 are adjustment coefficients, and satisfy 0<ω1<1, 0<ω2<1, ω1+ω2=1.

6. The method according to claim 1, characterized in that In S260, determining the adjustment coefficient based on the three-phase imbalance of each sub-cycle of the transformer in the most recent detection cycle, and updating the detection cycle based on the adjustment coefficient, includes: S261, obtaining the three-phase imbalance degree of the transformer in each sub-cycle; S262, comparing the three-phase unbalance degree in each of the sub-cycles with the first tolerance threshold, obtaining the number of times the three-phase unbalance degree of the transformer exceeds the first tolerance threshold in the most recent detection cycle, and recording it as a first cumulative number; S263, determining whether the first cumulative number is greater than 0, if so, executing S264, if not, executing S265; S264, setting the adjustment coefficient to k1 / 2 m , update the detection period to k1·T1 / 2 m ; Wherein, k1 is a preset proportional coefficient, 0<k1<1, m is the first cumulative number, and T1 is the duration of the most recent detection cycle; S265, comparing the three-phase unbalance degree in each of the sub-cycles with the second tolerance threshold, obtaining the number of times the three-phase unbalance degree of the transformer is lower than the second tolerance threshold in the most recent detection cycle, and recording it as a second cumulative number; wherein the second tolerance threshold is less than the first tolerance threshold, and the first tolerance threshold is less than the unbalance degree threshold; S266, setting the adjustment coefficient to k2·2 n , update the detection period to k2·T1·2 n ; Wherein, k2 is a preset proportional coefficient, 0.5<k2<1, and n is the second cumulative number.

7. A three-phase unbalanced regulation system for an AC charging stack, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method according to any one of claims 1 to 6.

8. A computer-readable storage medium storing a program executable by a processor, characterized in that: The processor-executable program is used to perform the method according to any one of claims 1 to 6 when executed by the processor.

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