A power coordination control method of a charging system

Abstract

The application discloses a power coordination control method of a charging system and relates to the technical field of charging piles, and comprises the following steps: S1: acquiring three-phase voltage of a power grid in real time, obtaining three-phase safe voltage of the power grid through the three-phase voltage of the power grid, acquiring a maximum allowable working current, acquiring a power factor, obtaining a maximum power limit value of a PCS through the three-phase safe voltage of the power grid, the maximum allowable working current and the power factor; when a charging gun is converted from slow charging to fast charging and proposes a power up-regulation request, whether there is a power up-regulation space is judged through a total output power and the maximum power limit value of the PCS, so that different power up-regulation strategies are formulated according to the size of the up-regulation space, which is beneficial to avoiding PCS overcurrent faults caused by uncontrollable sequences of power adjustment, and is also beneficial to improving the safety of power adjustment, so that circuit oscillation is smaller and more stable and safe.

Description

Technical Field

[0001] This invention relates to the field of charging pile technology, specifically to a power coordination control method for a charging system. Background Technology

[0002] The charging pile uses a PCS and multiple DC-DC modules to form a charging system. The PCS, as the front-end power conversion unit, converts the DC / AC power from the grid or battery into a stable DC bus voltage. Multiple DC-DC modules are connected in parallel to the DC bus, and each DC-DC module is connected to a charging gun to realize the charging and discharging function of electric vehicles. Since the rated power of the PCS and the sum of the rated power of each DC-DC module are usually not perfectly matched, and the number of charging guns connected and the power demand change dynamically in actual operation, it is necessary to coordinate and control the system power to prevent PCS overload or overcurrent faults and ensure the safe and stable operation of the equipment.

[0003] In existing technologies, a common power limiting method is to directly set a maximum output power limit for each DC-DC module. The principle for setting this limit is to ensure that the cumulative maximum output power of all DC-DC modules does not exceed the rated total power of the preceding PCS. While this static limiting method is simple to implement, it has significant drawbacks: Firstly, the system architecture dictates that each charging gun can only connect a maximum of two DC-DC modules in parallel. When some charging guns are not in operation, the idle DC-DC modules are still limited by their fixed maximum output power and cannot allocate redundant power to the operating charging guns, resulting in low overall power utilization. Secondly, P... The actual output capability of the CS is not a constant value; it fluctuates within a certain range due to AC grid voltage fluctuations. For example, when the grid voltage increases, the maximum output power of the PCS increases accordingly. However, existing technology cannot detect this change and dynamically adjust the power allocation of the DC-DC modules, thus wasting the PCS's floating power space. In addition, when multiple charging guns are working simultaneously, if the power demand of a certain charging gun suddenly increases, and if the power adjustment sequence of each DC-DC module is improper, the instantaneous total power may exceed the PCS's capacity, triggering an overcurrent fault and affecting system reliability. Therefore, we propose a power coordination control method for the charging system. Summary of the Invention

[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a power coordination control method for a charging system to solve the aforementioned problems in the prior art.

[0005] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a power coordination control method for a charging system, comprising the following steps: S1: Real-time acquisition of three-phase grid voltage, obtaining three-phase grid safety voltage, obtaining maximum allowable operating current, obtaining power factor, and obtaining PCS maximum power limit value through three-phase grid safety voltage, maximum allowable operating current and power factor; S2: Obtain the output power of each charging gun DC-DC module, sum the output power of all charging gun DC-DC modules to obtain the total output power, and determine whether to reduce the limiting power of the DC-DC module by comparing the total output power with the maximum power limit of the PCS. If the limiting power of the DC-DC module is reduced, then formulate a power reduction strategy based on the maximum power limit of the PCS. S3: Determine if there is a power increase request from a charging gun. If so, determine if there is room for power increase by comparing the total output power with the maximum power limit of the PCS. If there is room for power increase, implement a power increase strategy for that charging gun. If there is no room for power increase, first implement a power reduction strategy for other charging guns, and then implement a power recovery strategy for all charging guns according to the maximum power limit of the PCS, until the power of the charging gun requesting power increase reaches the required power.

[0006] Preferably, in S1, the three-phase voltage of the power grid is acquired in real time, and the three-phase safety voltage of the power grid is obtained from the three-phase voltage of the power grid, specifically as follows: S101: Set the three-phase voltage measurement cycle of the power grid, obtain the current three-phase voltage of the power grid, obtain the three-phase voltage of the power grid up to the current three-phase voltage measurement cycle, mark it as the previous three-phase voltage of the power grid, and obtain the change in the three-phase voltage of the power grid by taking the absolute value of the difference between the previous three-phase voltage of the power grid and the current three-phase voltage of the power grid. S102: Set a preset threshold for the change in three-phase voltage of the power grid, determine whether the change in three-phase voltage of the power grid is greater than the preset threshold, if the change in three-phase voltage of the power grid is greater than the preset threshold, mark the current three-phase voltage of the power grid as the safe three-phase voltage of the power grid, if the change in three-phase voltage of the power grid is less than or equal to the preset threshold, mark the previous three-phase voltage of the power grid as the safe three-phase voltage of the power grid.

[0007] Preferably, in S1, the maximum power limit value of the PCS is obtained through the three-phase safe voltage of the power grid, the maximum allowable operating current, and the power factor. The specific calculation method for the maximum power limit value of the PCS is as follows:

[0008] Where P represents the maximum power limit of the PCS, I represents the maximum allowable operating current, and U represents the three-phase safety voltage of the power grid. It is expressed as the power factor.

[0009] Preferably, in S2, the determination of whether to reduce the limiting power of the DC-DC module is based on the total output power and the maximum power limit value of the PCS, specifically: S201: Obtain the total output power, obtain the maximum power limit value of PCS, and obtain the power difference by subtracting the maximum power limit value of PCS from the total output power; S202: Determine if the power difference is greater than 0. If the power difference is greater than 0, the determination result is marked as no need to reduce the limit power of the DC-DC module. If the power difference is less than or equal to 0, the determination result is marked as needing to reduce the limit power of the DC-DC module.

[0010] Preferably, in S2, if the power limit of the DC-DC module is reduced, a power reduction strategy is formulated based on the maximum power limit of the PCS, specifically as follows: S203: Obtain the power difference, obtain the total number of DC-DC modules in the charging gun that are currently working, and obtain the average power difference by dividing the power difference by the total number of DC-DC modules in the charging gun that are currently working; S204: Obtain the limited power of each DC-DC module currently in operation, obtain the actual output power of each DC-DC module currently in operation, and determine whether the actual output power of the DC-DC module currently in operation is the limited power of the DC-DC module. If the actual output power of the charging gun DC-CDC module is equal to the limited power of the charging gun DC-CDC module, then the limited power of the charging gun DC-CDC module is reduced by a power average difference according to the low-speed descent slope control plan. The new limited power of the charging gun DC-CDC module after adjustment is obtained by subtracting the limited power of the charging gun DC-CDC module from the power average difference. If the actual output power of the charging gun DC-CDC module is not equal to the limit power of the charging gun DC-CDC module, the actual output power of the charging gun DC-CDC module is adjusted down by a power average difference according to the high-speed descent slope control plan. The new limit power of the charging gun DC-CDC module after adjustment is obtained by subtracting the actual output power of the charging gun DC-CDC module from the power average difference.

[0011] Preferably, in S204, the low-speed descent slope control plan specifically includes: obtaining the power average difference, dividing the power average difference by 5 to obtain the single adjustment value of the low-speed power average difference, setting the low-speed smoothing maintenance duration, and adjusting the limited power of the charging gun DC-DC module by one single adjustment value of the low-speed power average difference each time, with an interval of one low-speed smoothing maintenance duration after each adjustment, repeating the cycle until the limited power of the charging gun DC-DC module is reduced to the new limited power.

[0012] Preferably, in S204, the high-speed descent slope control plan specifically includes: obtaining the power average difference, setting the high-speed smoothing maintenance time, and the high-speed smoothing maintenance time being equal to two-thirds of the low-speed smoothing maintenance time; dividing the power average difference by 3 to obtain the single adjustment value of the high-speed power average difference; adjusting the actual output power of the charging gun DC-DC module by one single adjustment value of the high-speed power average difference each time, and pausing for one high-speed smoothing maintenance time after each adjustment, repeating the cycle until the actual output power of the charging gun DC-DC module is reduced to the new limit power.

[0013] Preferably, in S3, the presence of power adjustment space is determined by comparing the total output power with the maximum power limit of the PCS, specifically as follows: S301: Obtain the total output power, obtain the maximum power limit value of PCS, and obtain the power space value by subtracting the maximum power limit value of PCS from the total output power; S302: Obtain the power increase value through the power increase request of the charging gun, and determine whether the power increase value is less than the power space value. If the power increase value is less than the power space value, the judgment result is marked as having power increase space. If the power increase value is greater than or equal to the power space value, the judgment result is marked as not having power increase space.

[0014] Preferably, in S3, if there is room for power increase, a power increase strategy is implemented for the charging gun, specifically as follows: S303: Obtain the power increase value by requesting the power increase of the charging gun, obtain the actual output power of the charging gun's DC-CDC module, and obtain the target power by summing the actual output power of the charging gun's DC-CDC module with the power increase value; S304: Divide the power increase value with 5 to obtain the high-speed power increase single adjustment value, set the high-speed adjustment maintenance time, and increase the actual output power of the charging gun's DCDC module by one high-speed power increase single adjustment value each time, with an interval of one high-speed adjustment maintenance time after each increase, repeating the cycle until the actual output power of the charging gun's DCDC module reaches the target power.

[0015] Preferably, in S3, if there is no room for power increase, a power reduction strategy is first implemented for other charging guns, and then a power recovery strategy is implemented for all charging guns according to the maximum power limit of PCS, until the power of the charging gun requesting power increase reaches the required power, specifically: S305: Obtain the power increase value through the power increase request of the charging gun, obtain the number of all other working charging guns, obtain the average reduction value by quotient of the power increase value and the number of all other working charging guns, and reduce the actual output power of all other working charging guns by an average reduction value according to the low-speed descent slope control plan. S306: Obtain the actual output power of the charging gun's DC-DC module. Sum the actual output power of the charging gun's DC-DC module with the power adjustment value to obtain the target power. Divide the power adjustment value with 7 to obtain the low-speed power adjustment single adjustment value. Set the low-speed adjustment maintenance time, which is 1.5 times the high-speed adjustment maintenance time. Increase the actual output power of the charging gun's DC-DC module by one low-speed power adjustment single adjustment value each time, with a low-speed adjustment maintenance time interval after each increase. Repeat the cycle until the actual output power of the charging gun's DC-DC module reaches the target power.

[0016] (III) Beneficial Effects This invention provides a power coordination control method for a charging system, which has the following beneficial effects: (1) In this scheme, the three-phase safe voltage of the power grid is obtained through the three-phase voltage of the power grid. Then, the power adjustment change can be judged according to the magnitude of the power grid voltage fluctuation. This avoids the frequent power adjustment caused by direct power adjustment due to small voltage fluctuations. The maximum power limit value of the PCS is obtained through the three-phase safe voltage of the power grid, the maximum allowable operating current and the power factor. This makes it easier to grasp the maximum power that the PCS can withstand according to the real-time voltage of the power grid. This makes it easier to dynamically adjust the power limit of the charging gun according to the maximum power that the PCS can withstand, and thus facilitates the full utilization of the power of the charging gun.

[0017] (2) In this scheme, the total output power is obtained by summing the output power of all charging gun DCDC modules. Then, the limit power of the DCDC module is determined based on the total output power and the maximum power limit of the PCS. This makes it easier to reduce the limit power of the DCDC module when the total output power is higher than the maximum power limit of the PCS, thereby avoiding the failure of the equipment to operate normally due to overpower or overcurrent faults. The power reduction strategy achieves a ramp-down of power, which is beneficial to avoid circuit faults caused by the power drop too fast, and at the same time, it can reduce the total output power to below the maximum power limit of the PCS as soon as possible.

[0018] (3) In this scheme, when a charging gun requests to increase power from slow charging to fast charging, the total output power and the maximum power limit of the PCS are used to determine whether there is room for power increase. Different power increase strategies are formulated according to the size of the increase space. This is beneficial to avoid PCS overcurrent faults caused by the uncontrollable order of power adjustment, and also beneficial to improve the safety of power adjustment, making the circuit oscillation smaller and more stable and safer. Attached Figure Description

[0019] Figure 1 This is a flowchart of a power coordination control method for a charging system according to the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figure 1 The present invention provides a power coordination control method for a charging system, comprising the following steps: S1: Real-time acquisition of three-phase grid voltage, obtaining three-phase grid safety voltage, obtaining maximum allowable operating current, obtaining power factor, and obtaining PCS maximum power limit value through three-phase grid safety voltage, maximum allowable operating current and power factor; S2: Obtain the output power of each charging gun DC-DC module, sum the output power of all charging gun DC-DC modules to obtain the total output power, and determine whether to reduce the limiting power of the DC-DC module by comparing the total output power with the maximum power limit of the PCS. If the limiting power of the DC-DC module is reduced, then formulate a power reduction strategy based on the maximum power limit of the PCS. S3: Determine if there is a request to increase the power of a charging gun. If so, determine whether there is room for power increase by comparing the total output power with the maximum power limit of the PCS. If there is room for power increase, implement a power increase strategy for the charging gun. If there is no room for power increase, first implement a power reduction strategy for other charging guns, and then implement a power recovery strategy for all charging guns according to the maximum power limit of the PCS, until the power of the charging gun requesting power increase reaches the required power. In S1, the maximum power limit value of the PCS is obtained through the three-phase safe voltage of the power grid, the maximum allowable operating current, and the power factor. The specific calculation method for the maximum power limit value of the PCS is as follows:

[0022] Where P represents the maximum power limit of the PCS, I represents the maximum allowable operating current, and U represents the three-phase safety voltage of the power grid. It is expressed as the power factor.

[0023] In this embodiment, the three-phase safe voltage of the power grid is obtained through the three-phase voltage of the power grid. The magnitude of the power grid voltage fluctuation is then used to determine whether the power adjustment can be met, thus avoiding frequent power adjustments caused by direct power adjustments due to small-range voltage fluctuations. The maximum power limit of the PCS is obtained through the three-phase safe voltage of the power grid, the maximum allowable operating current, and the power factor. This makes it easier to determine the maximum power that the PCS can withstand based on the real-time voltage of the power grid, and further facilitates the dynamic adjustment of the power limit of the charging gun based on the maximum power that the PCS can withstand, thereby facilitating the full utilization of the charging gun's power. In this solution, the total output power is obtained by summing the output power of all DCDC modules in the charging gun. Then, based on the total output power and the maximum power limit of the PCS, it is determined whether to reduce the limiting power of the DCDC modules. This makes it easier to reduce the limiting power of the DCDC modules when the total output power is higher than the maximum power limit of the PCS, thereby avoiding overpower or overcurrent faults that would prevent the equipment from operating normally. The power reduction strategy achieves a gradual power reduction, which helps to avoid circuit faults caused by excessively rapid power drop while quickly reducing the total output power below the maximum power limit of the PCS. In this solution, when a charging gun requests a power increase from slow charging to fast charging, the system determines whether there is room for power increase by comparing the total output power with the maximum power limit of the PCS. Based on the size of this room, different power increase strategies are implemented. If there is sufficient room, the power is increased relatively quickly, preventing conflicts caused by other charging guns also increasing their power during the power increase process. A ramp-up approach is used in the power increase strategy to avoid circuit failures due to excessively rapid power increases. If there is insufficient room, the power of other charging guns is first reduced, and then the power of all charging guns is simultaneously increased to execute a power recovery strategy. This provides sufficient room for the charging gun switching from slow to fast charging and also avoids PCS overcurrent failures caused by uncontrollable power adjustment sequences, improving the safety of power adjustment. Unlike the power increase strategy, which requires a rapid increase to gain room, the power recovery strategy uses a slower ramp-up approach, resulting in less circuit oscillation and greater stability and safety. It is worth mentioning that the value of the preset threshold in this scheme can be obtained through weight analysis, which will not be elaborated on here.

[0024] In S1, the three-phase voltage of the power grid is acquired in real time, and the three-phase safety voltage of the power grid is obtained from the three-phase voltage of the power grid, specifically as follows: S101: Set the three-phase voltage measurement cycle of the power grid, obtain the current three-phase voltage of the power grid, obtain the three-phase voltage of the power grid up to the current three-phase voltage measurement cycle, mark it as the previous three-phase voltage of the power grid, and obtain the change in the three-phase voltage of the power grid by taking the absolute value of the difference between the previous three-phase voltage of the power grid and the current three-phase voltage of the power grid. S102: Set a preset threshold for the change in three-phase voltage of the power grid, determine whether the change in three-phase voltage of the power grid is greater than the preset threshold, if the change in three-phase voltage of the power grid is greater than the preset threshold, mark the current three-phase voltage of the power grid as the safe three-phase voltage of the power grid, if the change in three-phase voltage of the power grid is less than or equal to the preset threshold, mark the previous three-phase voltage of the power grid as the safe three-phase voltage of the power grid.

[0025] In this embodiment, the three-phase safe voltage of the power grid is obtained through the three-phase voltage of the power grid. Then, based on the magnitude of the power grid voltage fluctuation, it is determined whether the power adjustment can be met, thereby avoiding frequent power adjustments caused by direct power adjustments due to small-range voltage fluctuations.

[0026] In S2, the decision to reduce the limiting power of the DC-DC module is made by comparing the total output power with the maximum power limit of the PCS. Specifically: S201: Obtain the total output power, obtain the maximum power limit value of PCS, and obtain the power difference by subtracting the maximum power limit value of PCS from the total output power; S202: Determine if the power difference is greater than 0. If the power difference is greater than 0, the determination result is marked as no need to reduce the limit power of the DC-DC module. If the power difference is less than or equal to 0, the determination result is marked as the need to reduce the limit power of the DC-DC module. In S2, if the power limit of the DC-DC module is reduced, a power reduction strategy is formulated based on the maximum power limit of the PCS, specifically as follows: S203: Obtain the power difference, obtain the total number of DC-DC modules in the charging gun that are currently working, and obtain the average power difference by dividing the power difference by the total number of DC-DC modules in the charging gun that are currently working; S204: Obtain the limited power of each DC-DC module currently in operation, obtain the actual output power of each DC-DC module currently in operation, and determine whether the actual output power of the DC-DC module currently in operation is the limited power of the DC-DC module. If the actual output power of the charging gun DC-CDC module is equal to the limited power of the charging gun DC-CDC module, then the limited power of the charging gun DC-CDC module is reduced by a power average difference according to the low-speed descent slope control plan. The new limited power of the charging gun DC-CDC module after adjustment is obtained by subtracting the limited power of the charging gun DC-CDC module from the power average difference. If the actual output power of the charging gun DC-CDC module is not equal to the limit power of the charging gun DC-CDC module, the actual output power of the charging gun DC-CDC module is adjusted down by a power average difference according to the high-speed descent slope control plan. The new limit power of the charging gun DC-CDC module after adjustment is obtained by subtracting the actual output power of the charging gun DC-CDC module from the power average difference.

[0027] In this embodiment, the total output power is obtained by summing the output power of all charging gun DC-DC modules. Then, based on the total output power and the maximum power limit of the PCS, it is determined whether to reduce the limiting power of the DC-DC modules. This facilitates the reduction of the limiting power of the DC-DC modules when the total output power is higher than the maximum power limit of the PCS, thereby avoiding overpower or overcurrent faults that could cause the equipment to malfunction. The power reduction strategy achieves a gradual power decrease, which helps to avoid circuit faults caused by excessively rapid power drops while quickly reducing the total output power below the maximum power limit of the PCS.

[0028] In S204, the low-speed descent slope control plan is as follows: obtain the power average difference, divide the power average difference with 5 to obtain the low-speed power average difference single adjustment value, set the low-speed smoothing maintenance duration, and lower the limit power of the charging gun DC-DC module by one low-speed power average difference single adjustment value each time, with an interval of one low-speed smoothing maintenance duration after each adjustment, repeating the cycle until the limit power of the charging gun DC-DC module is lowered to the new limit power.

[0029] In this embodiment, since the actual output power of the charging gun DC-CDC module is equal to the limited power of the charging gun DC-CDC module, the power of the charging gun DC-CDC module cannot be adjusted beyond the upper limit in fast charging mode. Therefore, a low-speed descent slope control plan with a relatively longer adjustment time and interval time can be adopted to further reduce the power by making the circuit oscillation smaller and more stable and safer.

[0030] In S204, the high-speed descent slope control plan is as follows: obtain the power average difference, set the high-speed smoothing maintenance time, and the high-speed smoothing maintenance time is equal to two-thirds of the low-speed smoothing maintenance time. Divide the power average difference by 3 to obtain the single adjustment value of the high-speed power average difference. Adjust the actual output power of the charging gun DC-DC module by one single adjustment value of the high-speed power average difference each time, and after each adjustment, pause for one high-speed smoothing maintenance time. Repeat the cycle until the actual output power of the charging gun DC-DC module is reduced to the new limit power.

[0031] In this embodiment, since the actual output power of the charging gun DC-CDC module is not equal to the limited power of the charging gun DC-CDC module, the power of the charging gun DC-CDC module is in slow charging mode. There is a possibility that the user may switch from slow charging to fast charging. Therefore, a high-speed descent slope control plan with a relatively shorter adjustment time and interval time is adopted to improve the descent speed while ensuring that the sloped descent adjustment power is safer and more stable, and to avoid the user adjusting the charging mode during the descent process.

[0032] In S3, the presence of room for power increase is determined by comparing the total output power with the maximum power limit of the PCS. Specifically: S301: Obtain the total output power, obtain the maximum power limit value of PCS, and obtain the power space value by subtracting the maximum power limit value of PCS from the total output power; S302: Obtain the power increase value by requesting the power increase of the charging gun, and determine whether the power increase value is less than the power space value. If the power increase value is less than the power space value, the judgment result is marked as having power increase space. If the power increase value is greater than or equal to the power space value, the judgment result is marked as not having power increase space. In S3, if there is room for power increase, a power increase strategy will be implemented for the charging gun, specifically as follows: S303: Obtain the power increase value by requesting the power increase of the charging gun, obtain the actual output power of the charging gun's DC-CDC module, and obtain the target power by summing the actual output power of the charging gun's DC-CDC module with the power increase value; S304: Divide the power increase value with 5 to obtain the high-speed power increase single adjustment value, set the high-speed adjustment maintenance time, and increase the actual output power of the charging gun's DCDC module by one high-speed power increase single adjustment value each time, with an interval of one high-speed adjustment maintenance time after each increase, repeating the cycle until the actual output power of the charging gun's DCDC module reaches the target power.

[0033] In this embodiment, when a charging gun requests an increase in power from slow charging to fast charging, the total output power and the maximum power limit of the PCS are used to determine whether there is room for power increase. Based on the size of the increase space, different power increase strategies are formulated. If the increase space is sufficient, the power is increased relatively quickly through the power increase strategy. This helps to avoid the phenomenon of insufficient increase space caused by other charging guns also increasing their power during the power increase process. The power increase strategy also adopts a ramp-like incremental method, which helps to avoid circuit failure caused by excessively rapid power increase.

[0034] In S3, if there is no room for power increase, a power reduction strategy is first applied to other charging guns, and then a power recovery strategy is applied to all charging guns according to the maximum power limit of PCS, until the power of the charging gun requesting power increase reaches the required power. Specifically: S305: Obtain the power increase value through the power increase request of the charging gun, obtain the number of all other working charging guns, obtain the average reduction value by quotient of the power increase value and the number of all other working charging guns, and reduce the actual output power of all other working charging guns by an average reduction value according to the low-speed descent slope control plan. S306: Obtain the actual output power of the charging gun's DC-DC module. Sum the actual output power of the charging gun's DC-DC module with the power adjustment value to obtain the target power. Divide the power adjustment value with 7 to obtain the low-speed power adjustment single adjustment value. Set the low-speed adjustment maintenance time, which is 1.5 times the high-speed adjustment maintenance time. Increase the actual output power of the charging gun's DC-DC module by one low-speed power adjustment single adjustment value each time, with a low-speed adjustment maintenance time interval after each increase. Repeat the cycle until the actual output power of the charging gun's DC-DC module reaches the target power.

[0035] In this embodiment, if there is insufficient upward adjustment space, the power of other charging guns is reduced first, and then the power of all charging guns is simultaneously increased to execute the power recovery strategy. This provides sufficient upward adjustment space for the charging guns that are switching from slow charging to fast charging, and also helps to avoid PCS overcurrent faults caused by the uncontrollable order of power adjustment. This is beneficial to improving the safety of power adjustment. Unlike the power increase strategy, the power recovery strategy does not need to rush to gain upward adjustment space. Therefore, the power recovery strategy adopts a slower ramp-up method, which makes the circuit oscillation smaller and more stable and safer.

[0036] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0037] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0038] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A power coordination control method for a charging system, characterized in that, Includes the following steps: S1: Real-time acquisition of three-phase grid voltage, obtaining three-phase grid safety voltage, obtaining maximum allowable operating current, obtaining power factor, and obtaining PCS maximum power limit value through three-phase grid safety voltage, maximum allowable operating current and power factor; S2: Obtain the output power of each charging gun DC-DC module, sum the output power of all charging gun DC-DC modules to obtain the total output power, and determine whether to reduce the limiting power of the DC-DC module by comparing the total output power with the maximum power limit of the PCS. If the limiting power of the DC-DC module is reduced, then formulate a power reduction strategy based on the maximum power limit of the PCS. S3: Determine if there is a power increase request from a charging gun. If so, determine if there is room for power increase by comparing the total output power with the maximum power limit of the PCS. If there is room for power increase, implement a power increase strategy for that charging gun. If there is no room for power increase, first implement a power reduction strategy for other charging guns, and then implement a power recovery strategy for all charging guns according to the maximum power limit of the PCS, until the power of the charging gun requesting power increase reaches the required power.

2. The power coordination control method for a charging system according to claim 1, characterized in that: In S1, the three-phase voltage of the power grid is acquired in real time, and the three-phase safety voltage of the power grid is obtained from the three-phase voltage of the power grid, specifically as follows: S101: Set the three-phase voltage measurement cycle of the power grid, obtain the current three-phase voltage of the power grid, obtain the three-phase voltage of the power grid up to the current three-phase voltage measurement cycle, mark it as the previous three-phase voltage of the power grid, and obtain the change in the three-phase voltage of the power grid by taking the absolute value of the difference between the previous three-phase voltage of the power grid and the current three-phase voltage of the power grid. S102: Set a preset threshold for the change in three-phase voltage of the power grid, determine whether the change in three-phase voltage of the power grid is greater than the preset threshold, if the change in three-phase voltage of the power grid is greater than the preset threshold, mark the current three-phase voltage of the power grid as the safe three-phase voltage of the power grid, if the change in three-phase voltage of the power grid is less than or equal to the preset threshold, mark the previous three-phase voltage of the power grid as the safe three-phase voltage of the power grid.

3. The power coordination control method for a charging system according to claim 1, characterized in that: In S1, the maximum power limit value of the PCS is obtained through the three-phase safe voltage of the power grid, the maximum allowable operating current, and the power factor. The specific calculation method for the maximum power limit value of the PCS is as follows: Where P represents the maximum power limit of the PCS, I represents the maximum allowable operating current, and U represents the three-phase safety voltage of the power grid. It is expressed as the power factor.

4. The power coordination control method for a charging system according to claim 1, characterized in that: In S2, the decision to reduce the limiting power of the DC-DC module is made by comparing the total output power with the maximum power limit of the PCS. Specifically: S201: Obtain the total output power, obtain the maximum power limit value of PCS, and obtain the power difference by subtracting the maximum power limit value of PCS from the total output power; S202: Determine if the power difference is greater than 0. If the power difference is greater than 0, the determination result is marked as no need to reduce the limit power of the DC-DC module. If the power difference is less than or equal to 0, the determination result is marked as needing to reduce the limit power of the DC-DC module.

5. The power coordination control method for a charging system according to claim 4, characterized in that: In S2, if the power limit of the DC-DC module is reduced, a power reduction strategy is formulated based on the maximum power limit of the PCS, specifically as follows: S203: Obtain the power difference, obtain the total number of DC-DC modules in the charging gun that are currently working, and obtain the average power difference by dividing the power difference by the total number of DC-DC modules in the charging gun that are currently working; S204: Obtain the limited power of each DC-DC module currently in operation, obtain the actual output power of each DC-DC module currently in operation, and determine whether the actual output power of the DC-DC module currently in operation is the limited power of the DC-DC module. If the actual output power of the charging gun DC-CDC module is equal to the limited power of the charging gun DC-CDC module, then the limited power of the charging gun DC-CDC module is reduced by a power average difference according to the low-speed descent slope control plan. The new limited power of the charging gun DC-CDC module after adjustment is obtained by subtracting the limited power of the charging gun DC-CDC module from the power average difference. If the actual output power of the charging gun DC-CDC module is not equal to the limit power of the charging gun DC-CDC module, the actual output power of the charging gun DC-CDC module is adjusted down by a power average difference according to the high-speed descent slope control plan. The new limit power of the charging gun DC-CDC module after adjustment is obtained by subtracting the actual output power of the charging gun DC-CDC module from the power average difference.

6. The power coordination control method for a charging system according to claim 5, characterized in that: In S204, the low-speed descent slope control plan is as follows: obtain the power average difference, divide the power average difference with 5 to obtain the low-speed power average difference single adjustment value, set the low-speed smoothing maintenance duration, and lower the limit power of the charging gun DC-DC module by one low-speed power average difference single adjustment value each time, with an interval of one low-speed smoothing maintenance duration after each adjustment, repeating the cycle until the limit power of the charging gun DC-DC module is lowered to the new limit power.

7. The power coordination control method for a charging system according to claim 6, characterized in that: In S204, the high-speed descent slope control plan is as follows: obtain the power average difference, set the high-speed smoothing maintenance time, and the high-speed smoothing maintenance time is equal to two-thirds of the low-speed smoothing maintenance time. Divide the power average difference by 3 to obtain the single adjustment value of the high-speed power average difference. Adjust the actual output power of the charging gun DC-DC module by one single adjustment value of the high-speed power average difference each time, and after each adjustment, pause for one high-speed smoothing maintenance time. Repeat the cycle until the actual output power of the charging gun DC-DC module is reduced to the new limit power.

8. The power coordination control method for a charging system according to claim 1, characterized in that: In S3, the presence of room for power increase is determined by comparing the total output power with the maximum power limit of the PCS. Specifically: S301: Obtain the total output power, obtain the maximum power limit value of PCS, and obtain the power space value by subtracting the maximum power limit value of PCS from the total output power; S302: Obtain the power increase value through the power increase request of the charging gun, and determine whether the power increase value is less than the power space value. If the power increase value is less than the power space value, the judgment result is marked as having power increase space. If the power increase value is greater than or equal to the power space value, the judgment result is marked as not having power increase space.

9. The power coordination control method for a charging system according to claim 1, characterized in that: In S3, if there is room for power increase, a power increase strategy will be implemented for the charging gun, specifically as follows: S303: Obtain the power increase value by requesting the power increase of the charging gun, obtain the actual output power of the charging gun's DC-CDC module, and obtain the target power by summing the actual output power of the charging gun's DC-CDC module with the power increase value; S304: Divide the power increase value with 5 to obtain the high-speed power increase single adjustment value, set the high-speed adjustment maintenance time, and increase the actual output power of the charging gun's DCDC module by one high-speed power increase single adjustment value each time, with an interval of one high-speed adjustment maintenance time after each increase, repeating the cycle until the actual output power of the charging gun's DCDC module reaches the target power.

10. The power coordination control method for a charging system according to claim 5, characterized in that: In S3, if there is no room for power increase, a power reduction strategy is first applied to other charging guns, and then a power recovery strategy is applied to all charging guns according to the maximum power limit of PCS, until the power of the charging gun requesting power increase reaches the required power. Specifically: S305: Obtain the power increase value through the power increase request of the charging gun, obtain the number of all other working charging guns, obtain the average reduction value by quotient of the power increase value and the number of all other working charging guns, and reduce the actual output power of all other working charging guns by an average reduction value according to the low-speed descent slope control plan. S306: Obtain the actual output power of the charging gun's DC-DC module. Sum the actual output power of the charging gun's DC-DC module with the power adjustment value to obtain the target power. Divide the power adjustment value with 7 to obtain the low-speed power adjustment single adjustment value. Set the low-speed adjustment maintenance time, which is 1.5 times the high-speed adjustment maintenance time. Increase the actual output power of the charging gun's DC-DC module by one low-speed power adjustment single adjustment value each time, with a low-speed adjustment maintenance time interval after each increase. Repeat the cycle until the actual output power of the charging gun's DC-DC module reaches the target power.

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