Control method based on charging station energy management system

Abstract

The invention provides a control method based on a charging station energy management system, and the system comprises an energy management host and a plurality of energy management sub-controllers which are in communication connection with the energy management host. Comprising the steps that S1, the energy management host receives state information sent by the multiple energy management sub-controllers respectively, and the state information comprises the state of charge SOC, the required power Np and the buffer distribution proportion B of the corresponding electric equipment; s2, the energy management host obtains the total power MPW of the charging station, obtains the total power APW of the upper limit value of the energy buffer area distributed to each energy management sub-controller, and calculates the residual distributable power RPW; in the charging peak period, when the multiple sub-controllers carry out rapid power adjustment at the same time, the response time can still be stably kept at the millisecond level, so that rapid suppression can be achieved during instantaneous load fluctuation, and the problems of transformer overload and power distribution imbalance are effectively prevented.

Description

Technical Field

[0001] This invention relates to the field of charging energy management technology, and in particular to a control method based on a charging station energy management system. Background Technology

[0002] With the continuous growth in the number of new energy vehicles, the proportion of high-power charging piles in charging stations is increasing year by year, and the changes in instantaneous charging load are becoming more frequent and drastic. Most existing charging station energy management systems adopt a master-slave control architecture, that is, the energy management host (master control end) uniformly receives the power requests from each energy management sub-control (slave control end), and after calculation, issues control commands to each sub-control.

[0003] Under this architecture, before each power adjustment, the sub-control unit must first send a power adjustment request to the main control unit and wait for the main control unit to calculate and provide feedback before it can perform the adjustment. This polling-based decision-making inevitably introduces communication delay and calculation queuing delay, which is particularly noticeable during peak charging periods.

[0004] When multiple sub-control units in a charging station simultaneously initiate power adjustment requests, the accumulated delay can cause the response time to rise from milliseconds to hundreds of milliseconds or even longer, making it impossible to suppress instantaneous load fluctuations in a timely manner and increasing the risk of transformer overload and power distribution imbalance.

[0005] Therefore, a control method based on the energy management system of charging stations is proposed. Summary of the Invention

[0006] In view of this, the present invention provides a control method based on a charging station energy management system to solve or alleviate the technical problems existing in the prior art, and at least provides a beneficial option.

[0007] The technical solution of the present invention is implemented as follows: a control method based on a charging station energy management system, wherein the charging station energy management system includes an energy management host and multiple energy management sub-controllers communicatively connected to the energy management host, and the method includes the following steps:

[0008] S1. The energy management host receives status information sent by the multiple energy management sub-controllers respectively. The status information includes the state of charge (SOC), power demand (Np), and buffer allocation ratio (B) of the applied electrical equipment.

[0009] S2. The energy management host obtains the total power MPW of the charging station and the total power APW that has been allocated to the upper limit of the energy buffer between each energy management sub-control, and calculates the remaining allocable power RPW, where: RPW = MPW - APW;

[0010] S3. The energy management host calculates the upper limit value UBC of the energy buffer interval of the target energy management sub-control according to the remaining allocable power RPW, the state of charge SOC of the electrical equipment, the demand power Np, and the buffer allocation ratio B, where: UBC = (100 - SOC) × B + Np;

[0011] S4. The energy management host sets the lower limit value of the energy buffer interval to 0, the upper limit value to the upper limit value UBC, and sends this energy buffer interval to the target energy management sub-control;

[0012] S5. In the case of a power increase demand or a power decrease demand within the energy buffer interval, the target energy management sub-control directly adjusts the output power to the demand power without sending a confirmation request to the energy management host;

[0013] S6. When the demand power exceeds the upper limit value UBC of the energy buffer interval, the target energy management sub-control limits the output power to the upper limit value UBC and sends an update request to the energy management host to trigger the energy management host to recalculate and allocate the energy buffer interval;

[0014] S7. The energy management host determines whether to update the energy buffer interval of the target energy management sub-control based on the comparison result between the difference between the previous buffer interval upper limit value PUBC and the currently calculated buffer interval upper limit value NUBC and the remaining allocable power RPW, where:

[0015] Update is performed when |NUBC - PUBC| < RPW, otherwise the previous energy buffer interval remains unchanged;

[0016] S8. The energy management host calculates the total remaining power allocable power change rate PVR according to the current total power MPW of the charging station, the currently allocated power APW, and the corresponding total power MPW' and allocated power APW' at the previous moment, where: PVR = ((MPW' - APW') - (MPW - APW)) / t;

[0017] t is the time interval between the previous moment and the current moment, MPW' is the total power of the charging station at the previous moment, APW' is the total allocated power at the previous moment. When the change rate PVR is greater than the preset threshold, the energy storage device is controlled to be in the on state.

[0018] More preferably, the energy management host periodically acquires the total active and reactive power data of the charging station through a three-phase smart meter installed on the low-voltage side of the transformer at the charging station, and acquires the transformer winding and oil temperature information in real time through a digital temperature sensor installed on the transformer tank wall; when the temperature information exceeds the rated operating temperature threshold, the energy management host reduces the total power limit of the charging station to 80% to 95% of the current maximum tolerable power.

[0019] More preferably, when calculating the upper limit value UBC of the energy buffer, the energy management host allocates different buffer allocation ratios B according to the type of electrical equipment, business priority, and task urgency.

[0020] More preferably, after receiving the energy buffer space issued by the energy management host, the target energy management sub-controller stores the upper and lower limits of the energy buffer space and the current output power value in a local cache module, and obtains the real-time power demand of the electrical equipment with a scanning period of 10ms to 50ms; when the power demand is within the range of the energy buffer space, the target energy management sub-controller directly adjusts the output power locally using pulse width modulation control to achieve millisecond-level response.

[0021] More preferably, when the required power is less than the upper limit value UBC of the energy buffer zone, the target energy management sub-controller will directly adjust the output power to the required power, and when the change in output power exceeds 10% of the previous change value, it will report the updated required power to the energy management host to synchronize the global power allocation data.

[0022] More preferably, the calculation cycle of the energy management host is 0.5 to 2 seconds, so as to issue an energy storage device activation command in a timely manner when the rate of change (PVR) suddenly increases.

[0023] More preferably, when the rate of change (PVR) is continuously lower than the preset threshold and the duration exceeds the time threshold T, and the charging station is in a low-load operation state, the energy management host controls the energy storage device to shut down in a step-by-step power reduction manner, first gradually reducing the output power of the energy storage device to 20% to 40% of the rated power, and then performing disconnection control.

[0024] More preferably, when the target energy management sub-controller detects any of the following situations, it immediately reports to the energy management host and enters a safe mode:

[0025] (1) The electrical equipment failed to start and two consecutive starting attempts were unsuccessful;

[0026] (2) The deviation between the measured output power and the set output power exceeds ±15% and lasts for more than 2 seconds;

[0027] (3) The internal protection device of the electrical equipment activates or detects that the insulation resistance is lower than the safe value;

[0028] Upon receiving the aforementioned anomaly report, the energy management host immediately suspends the power allocation for the target energy management sub-control and performs a global power reallocation.

[0029] The embodiments of the present invention have the following advantages due to the adoption of the above technical solutions:

[0030] I. This invention distributes the global power calculation results of the energy management host to each energy management sub-controller in a single go through the allocation of energy buffer zones, in the form of upper and lower limit ranges. Power changes within the range of the sub-controller do not require further confirmation from the host and can be directly adjusted locally. This eliminates the polling link in the traditional master-slave architecture where each power adjustment must go through "sub-controller request - host calculation - instruction issuance - sub-controller execution", avoiding the superposition of communication delay and calculation waiting time. During peak charging periods, when multiple sub-controllers perform rapid power adjustments simultaneously, the response time can still be stably maintained at the millisecond level, thereby enabling rapid suppression of instantaneous load fluctuations and effectively preventing transformer overload and power distribution imbalance problems.

[0031] Second, the energy buffer zone of this invention enables the power regulation behavior of the sub-control unit within the range to be completely controlled locally. Only when the actual demand exceeds the upper limit of the buffer zone or the power fluctuation exceeds the set threshold will an update request be sent to the energy management host and a global reallocation be triggered. This reduces the frequency of the energy management host processing a large number of minor power fluctuations in a short period of time, reduces the computing pressure and communication load of the energy management host, and avoids global response delays caused by computation queuing. At the same time, the rapid local adjustment of the energy management sub-control can quickly respond to power changes without the intervention of the host, maintaining the stability of the total load and the safe operation of the power distribution system.

[0032] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a flowchart illustrating the method steps of the present invention.

[0035] Figure 2 This is a flowchart of the calculation of the total remaining power available power change rate and the control of the energy storage device according to the present invention;

[0036] Figure 3 This is a schematic diagram illustrating the communication connection between the energy management host and multiple energy management sub-controllers of the present invention. Detailed Implementation

[0037] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0038] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0039] like Figure 1-3 As shown, this embodiment of the invention provides a control method based on a charging station energy management system. The charging station energy management system in this embodiment includes: an energy management host (hereinafter referred to as the host) and several energy management sub-controllers (hereinafter referred to as sub-controllers) connected to the host via a communication bus; the host undertakes functions such as global power monitoring, energy buffer allocation, and energy storage device scheduling; the sub-controllers undertake local power regulation and status monitoring functions for their respective charging units or other electrical equipment. Their communication methods can adopt Ethernet, fiber optics, or industrial buses (Modbus TCP, CAN bus, etc.); the method includes the following steps:

[0040] Step S1: Status Information Acquisition and Transmission

[0041] The host periodically receives status information reported by each sub-controller. The status information of each sub-controller includes:

[0042] State of Charge (SOC): Represents the percentage of battery charge of the currently used electrical equipment (charging pile), with a value range of 0% to 100%.

[0043] Power demand Np: The instantaneous power value required by the sub-controller in the next scheduling cycle, in kW, which can be positive (charging) or negative (discharging / feedback);

[0044] Buffer allocation ratio B: The priority allocation ratio of this sub-control in the total power is determined based on the comprehensive factors of equipment type, business priority, and task urgency, and the value range is 0 to 1;

[0045] SOC can be obtained in real time through the BMS interface inside the charging pile; Np is calculated by the sub-controller in combination with historical power curves and real-time business requirements; B is issued by the host or a preset strategy and can be adjusted periodically.

[0046] Step S2: Global Power Calculation and Residual Power Determination

[0047] The host obtains the total power MPW of the charging station through the three-phase smart meter on the low-voltage side, in kW; at the same time, it sums the upper limit values ​​of the energy buffers between all the current sub-controls to obtain the total allocated power APW, and calculates the remaining allocable power RPW: RPW = MPW - APW;

[0048] Among them, MPW and APW must be acquired at the same sampling time to avoid calculation deviations caused by asynchronous sampling. When RPW is positive, it means that there is still room for allocation. When it is negative, the allocated buffer space needs to be compressed.

[0049] Step S3: Calculation of the upper limit value between target sub-control buffer zones

[0050] After determining the target sub-controller and the sub-controllers that need to be adjusted or added, the host calculates the upper limit value UBC of its energy buffer zone based on RPW, SOC, Np and B: UBC = (100-SOC)×B+Np;

[0051] In the formula, (100-SOC)×B represents the additional power compensation amount allocated according to the state of charge and priority ratio, and Np is the basic power requirement of the sub-control. If the SOC is low and B is high, the UBC will increase significantly to prioritize meeting the fast charging needs of low-charged devices.

[0052] Step S4: Distribution between buffer zones

[0053] The host sets the lower limit of the buffer to 0 and the upper limit to UBC, and sends it to the target subcontroller through the communication link. The subcontroller stores the upper and lower limits in its local cache module and records the sending timestamp for comparison with subsequent update requests.

[0054] Step S5: Autonomous Adjustment within the Interval

[0055] When the real-time power demand of the sub-controller is within the allocated buffer range [0, UBC], the sub-controller does not need to send a request to the host. It can directly adjust the output power to the demand power through pulse width modulation (PWM) or frequency conversion control, achieving a fast response at the millisecond level, effectively shortening the control link and avoiding polling confirmation delay.

[0056] Step S6: Handling of out-of-range conditions

[0057] If the real-time required power exceeds UBC, the sub-control will limit the output power to UBC and immediately send an update request to the host. The update request includes: the current required power, the current SOC, the current UBC, and the reason for the excess (such as a sudden high-power request). After receiving the update request, the host enters step S7 to re-evaluate whether to allocate a higher UBC.

[0058] Step S7: Update judgment and allocation strategy

[0059] The host compares the difference between the newly calculated upper limit value NUBC and the previous upper limit value PUBC with RPW:

[0060] If ∣NUBC - PUBC∣ < RPW, it is considered that the global margin can support this adjustment, perform the update and send the new UBC to the sub-control;

[0061] Otherwise, keep PUBC unchanged to avoid global power overlimit.

[0062] Step S8: Calculation of the total remaining power change rate and energy storage scheduling

[0063] The host monitors the power dynamics of the charging station, and calculates the total remaining power change rate PVR based on the current total power MPW, the allocated power APW, as well as the previous total power MPW' and the allocated power APW':

[0064] PVR = (MPW' - APW') - (MPW - APW) / t;

[0065] When PVR > the preset threshold, the host sends an enabling instruction to the energy storage device to quickly release the energy storage power and suppress the total load fluctuation.

[0066] In this embodiment, the host periodically collects the total active power and reactive power through a three-phase intelligent meter installed on the low-voltage side of the transformer; at the same time, it uses a digital temperature sensor installed on the oil tank wall to monitor the winding and oil temperature in real time. When any temperature value exceeds the rated operating threshold (such as 85°C), the total power upper limit is automatically adjusted to 80% - 95% of the maximum tolerable power to prevent overheating damage.

[0067] In this embodiment, when calculating UBC, the value of B can be set according to different device types: for example, B = 0.8 for fast charging piles of buses, B = 0.5 for passenger car piles, and B = 0.2 for low-priority auxiliary loads. The higher the task urgency, the larger the value of B, so as to prioritize important services when power is tight.

[0068] In this embodiment, the sub-control stores the received UBC in the local cache and collects the real-time required power with a 10ms scanning period; if the required power is within the range, it is directly adjusted through the local PWM, and the response time can be less than 50ms to meet the high-power fast charging demand.

[0069] In this embodiment, when the required power is less than UBC, the output power is directly adjusted to the required power; if the change in power exceeds 10% compared to the previous power, it is immediately reported to the host so as to synchronize the global allocation data and ensure the coordination and consistency of multiple sub-controls.

[0070] In this embodiment, the host calculates the PVR periodically (0.5 to 2 seconds). When the PVR remains below the threshold for more than T (e.g., 60 seconds) and the host is in a low-load operating state (MPW < 40% of rated capacity), the energy storage output power is reduced step by step to 20% to 40% of the rated power, and then disconnection control is executed to reduce the impact of frequent start-stop of the energy storage device on its lifespan.

[0071] In this embodiment, the sub-controller detected one of the following anomalies:

[0072] (1) Two consecutive startup failures;

[0073] (2) The measured output power deviation from the set output power is >±15% and lasts for >2 seconds;

[0074] (3) If the internal protection activates or the insulation resistance falls below a safe value, immediately report to the host and enter safe mode. The host will suspend the power allocation for that sub-control and re-execute the global allocation strategy to ensure system safety.

[0075] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A control method based on a charging station energy management system, wherein the charging station energy management system includes an energy management host and multiple energy management sub-controllers communicatively connected to the energy management host, characterized in that: The method includes the following steps: S1. The energy management host receives the status information respectively sent by the multiple energy management sub-controls. The status information includes the state of charge (SOC), the required power (Np), and the buffer allocation ratio (B) of the corresponding power-consuming equipment. S2. The energy management host obtains the total power (MPW) of the charging station and the total power (APW) of the upper limit of the energy buffer interval already allocated to each energy management sub-control, and calculates the remaining allocable power (RPW), where: RPW = MPW - APW. S3. The energy management host calculates the upper limit value (UBC) of the energy buffer interval of the target energy management sub-control according to the remaining allocable power (RPW), the state of charge (SOC) of the power-consuming equipment, the required power (Np), and the buffer allocation ratio (B), where: UBC = (100 - SOC) × B + Np. S4. The energy management host sets the lower limit value of the energy buffer interval to 0, sets the upper limit value to the upper limit value (UBC), and sends this energy buffer interval to the target energy management sub-control. S5. For the power increase demand or power decrease demand within the energy buffer interval of the target energy management sub-control, without sending a confirmation request to the energy management host, directly adjust the output power to the required power. S6. When the required power exceeds the upper limit value (UBC) of the energy buffer interval, the target energy management sub-control limits the output power to the upper limit value (UBC) and sends an update request to the energy management host to trigger the energy management host to recalculate and allocate the energy buffer interval. S7. The energy management host determines whether to update the energy buffer interval of the target energy management sub-control based on the comparison result between the difference between the previous upper limit value (PUBC) of the buffer interval and the currently calculated upper limit value (NUBC) of the buffer interval and the remaining allocable power (RPW), where: Update is performed when |NUBC - PUBC| < RPW, otherwise keep the previous energy buffer interval unchanged. S8. The energy management host calculates the change rate (PVR) of the total remaining power allocable power according to the current total power (MPW) of the charging station, the currently allocated power (APW), the total power (MPW') and the allocated power (APW') corresponding to the previous moment, where: PVR = ((MPW' - APW') - (MPW - APW)) / t. t is the time interval between the previous moment and the current moment, MPW' is the total power of the charging station at the previous moment, APW' is the total allocated power at the previous moment. When the change rate (PVR) is greater than the preset threshold, control the energy storage device to be in the on state.

2. The control method based on the energy management system of a charging station according to claim 1, characterized in that: The energy management host periodically obtains the total active power and reactive power data of the charging station through a three-phase intelligent meter installed on the low-voltage side of the charging station transformer, and obtains the transformer winding and oil temperature information in real time through a digital temperature sensor installed on the transformer oil tank wall; when the temperature information exceeds the rated operating temperature threshold, the energy management host reduces the total power upper limit of the charging station to 80% - 95% of the current maximum tolerable power.

3. The control method based on the energy management system of a charging station according to claim 1, characterized in that: When calculating the upper limit value UBC of the energy buffer, the energy management host allocates different buffer allocation ratios B according to the type of electrical equipment, business priority, and task urgency.

4. The control method based on the energy management system of a charging station according to claim 1, characterized in that: After receiving the energy buffer range from the energy management host, the target energy management sub-controller stores the upper and lower limits of the energy buffer range and the current output power value in the local cache module, and obtains the real-time power demand of the electrical equipment with a scanning period of 10ms to 50ms. When the power demand is within the range of the energy buffer range, the target energy management sub-controller directly adjusts the output power locally using pulse width modulation control to achieve millisecond-level response.

5. The control method based on the energy management system of a charging station according to claim 1, characterized in that: When the required power is less than the upper limit value UBC of the energy buffer zone, the target energy management sub-controller will directly adjust the output power to the required power, and when the change in output power exceeds 10% of the previous change value, it will report the updated required power to the energy management host to synchronize the global power allocation data.

6. The control method based on the energy management system of a charging station according to claim 1, characterized in that: The calculation cycle of the energy management host is 0.5 to 2 seconds, so as to issue an energy storage device activation command in a timely manner when the rate of change (PVR) suddenly increases.

7. The control method based on the energy management system of a charging station according to claim 1, characterized in that: When the rate of change (PVR) remains below the preset threshold for an extended period exceeding the time threshold (T), and the charging station is operating under low load, the energy management host controls the energy storage device to shut down in a step-by-step power reduction manner. First, the output power of the energy storage device is gradually reduced to 20% to 40% of the rated power, and then disconnection control is executed.

8. The control method based on the energy management system of a charging station according to claim 1, characterized in that: When the target energy management sub-controller detects any of the following situations, it immediately reports to the energy management host and enters safe mode: (1) The electrical equipment failed to start and two consecutive starting attempts were unsuccessful; (2) The deviation between the measured output power and the set output power exceeds ±15% and lasts for more than 2 seconds; (3) The internal protection device of the electrical equipment activates or detects that the insulation resistance is lower than the safe value; Upon receiving the aforementioned anomaly report, the energy management host immediately suspends the power allocation for the target energy management sub-control and performs a global power reallocation.

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