Power distribution network peak regulation and frequency modulation charging pile micro-grid charging method and system

Abstract

The invention discloses a micro-grid charging method and system for peak and frequency modulation charging piles of a power distribution network, and the method comprises the steps: obtaining the final demand information of a user side, and obtaining the factors and factor values of the current power distribution network; based on a preset charging pile micro-grid master control system, generating a charging / discharging scheme according to the final demand information of the user side and the factor value of the current power distribution network, and arranging the electric vehicles into a charging sequence; the charging / discharging scheme is sent to a charging pile connected with the electric vehicle, a charging / discharging controller preset in the charging pile charges / discharges the electric vehicle, and bidirectionally measures the cost; after charging is completed, the charging / discharging controller disconnects the switch, charging is stopped, charging / discharging cost is obtained, and the charging / discharging cost is sent to the user side to be displayed based on the micro-grid platform; according to the invention, a reasonable charging scheme is designed by taking the final demand information of the user side as a basic criterion, convenience is provided for the electric vehicle user, and the cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle charging, and more specifically, to a microgrid charging method and system for a peak shaving and frequency modulation charging pile of a distribution network. Background Art

[0002] With the strong promotion of new energy vehicles by the state and the improvement of social requirements for environmental protection, the sales volume and social ownership of electric vehicles have both shown explosive growth; electric vehicles are usually replenished with energy by charging piles in the distribution network, which will inevitably increase the load of the distribution network; the typical specifications of electric vehicle charging services are in accordance with GB / T - 20234 - 2015. Referring to the current mainstream energy storage capacity of electric vehicles, the characteristics of such loads can be summarized as follows: 1) It contains elements for storing electrical energy, that is, electricity can flow from the grid side to the load side, and can also flow from the load side to the grid side; 2) There may be a demand for high-power fast charging, but this demand is not widespread, and it mostly exists in the form of low-power and low-speed charging modes; 3) The scale of a single charging load and energy storage is not large, belonging to distributed energy storage elements, but the number of loads shows explosive growth, and the total charging power is huge enough to impact the distribution network during peak load periods. If the active power of the grid is insufficient, it will lead to power quality problems such as a decrease in the grid frequency; 4) The charging time is mostly at night after work, spanning the peak and trough periods of residential electricity consumption; 5) The charging loads are distributed within residential communities, belonging to the load center; 6) They are sensitive to the cost of power consumption, that is, they expect the electricity price to be as low as possible. Therefore, the access of electric vehicles needs to solve the following problems: 1) Eliminate the impact on the distribution network load during the charging process, that is, achieve peak shaving of the distribution network; 2) When the active power of the grid is insufficient and the frequency drops, distributed energy storage devices participate in the frequency of the distribution network; 3) According to the expected usage of each vehicle and the battery maintenance plan, charge enough electricity as economically as possible and leave a margin; 4) Two-way power flow requires two-way billing and a more economical way to facilitate settlement.

[0003] Currently, there are usually three ways to achieve peak shaving for charging vehicle loads: One is that the dispatching center interacts with each vehicle charging pile through a communication network such as GPRS, and the dispatching center controls the real-time power of the charging pile to reduce the load during peak periods of the distribution network; the second is to control the charging time of the vehicle, stagger a part of the electric vehicles from the peak electricity consumption period and postpone them to the low electricity consumption period for charging, so as to balance the load in terms of time; the third way is to send the electrical energy stored in the electric vehicle back to the distribution network during the peak electricity consumption period to achieve the purpose of peak shaving and valley filling.

[0004] However, the method of scheduling real-time control of charging power requires real-time adjustment of the operation mode of the distribution network line, which is complex to operate and cannot perform peak shaving locally. The method of controlling the charging period is very inflexible and cannot meet the flexible charging methods of users. For example, if a vehicle needs 9 hours to charge, and the charging period is controlled during the low-power consumption period from 0:00 to 8:00, obviously the energy storage battery of this vehicle cannot be fully charged, nor can it meet the needs of vehicles in urgent need of charging. In addition, both of these methods can only allow electric vehicles to absorb energy from the power grid, but cannot feed back the remaining power of their own to the power grid, actively participate in the peak shaving and frequency modulation of the power grid, and optimize the power quality of the power grid. Although the above-mentioned third method feeds power back to the power grid, if some vehicles charge during the peak load period and absorb power from the power grid at the high electricity price of the peak load, it is not economical. Summary of the Invention

[0005] In order to solve at least one of the above technical problems, the object of the present invention is to provide a method and system for microgrid charging of a distribution network peak shaving and frequency modulation charging pile, which can design a reasonable charging scheme, provide convenience for electric vehicle users, and save costs.

[0006] The first aspect of the present invention provides a method for microgrid charging of a distribution network peak shaving and frequency modulation charging pile, including:

[0007] Obtain the final demand information of the user side, and obtain the factors and factor values of the current distribution network;

[0008] Based on a preset main control system of the charging pile microgrid, generate a charging / discharging scheme according to the final demand information of the user side and the factor values of the current distribution network, and arrange the electric vehicles in the charging sequence;

[0009] Send the charging / discharging scheme to the charging pile accessed by the electric vehicle, and the preset charging / discharging controller in the charging pile charges / discharges the electric vehicle and measures the cost bidirectionally;

[0010] After charging is completed, the charging / discharging controller disconnects the switch, stops charging, obtains the charging / discharging cost, and sends the charging / discharging cost to the user side based on the microgrid platform for display;

[0011] The factors of the current distribution network at least include the current distribution network capacity, load period and frequency; the final demand information at least includes the remaining power, the required charging amount and the pick-up time.

[0012] In this solution, before generating the charging / discharging scheme, it further includes:

[0013] According to the required charging amount and the charging power of the corresponding charging pile, obtain the expected charging time of the corresponding electric vehicle;

[0014] Obtain the current time, and obtain the allowable charging time according to the current time and the pick-up time;

[0015] When the estimated charging time is greater than the allowed charging time, trigger a time-insufficient prompt message and send the time-insufficient prompt message to the user terminal for display;

[0016] When the estimated charging time is equal to the allowed charging time, directly charge the electric vehicle without generating a charging / discharging plan;

[0017] When the estimated charging time is less than the allowed charging time, generate a charging / discharging plan according to the final demand information of the user terminal and the factor value of the current distribution network.

[0018] In this solution, the steps of generating the charging / discharging plan specifically include:

[0019] Extract the durations of the peak, flat, and valley periods in the allowed charging time;

[0020] Judge whether the valley duration of the allowed charging time is longer than the estimated charging time. If the allowed charging time completely falls within the interval of the valley duration, charging can be carried out solely using the valley duration;

[0021] If the allowed charging time not only falls within the valley duration, then judge whether the valley and flat durations of the allowed charging time are longer than the estimated charging time. If the sum of the valley and flat periods of the allowed charging time is greater than the estimated charging time, charge for all the valley durations and part of the flat duration;

[0022] If the allowed charging time spans three load periods, it is necessary to charge using all the valley and flat durations plus part of the peak duration.

[0023] This solution also includes:

[0024] Obtain the frequency of the current distribution network and the load period of the allowed charging time;

[0025] According to the load period of the allowed charging time, determine the range of the distribution network frequency corresponding to the load period;

[0026] If the frequency of the current distribution network is not within the range of the distribution network frequency corresponding to the load period, generate distribution network frequency modulation information;

[0027] Based on the distribution network frequency modulation information, obtain the remaining power of the electric vehicle;

[0028] Judge whether the remaining power of the electric vehicle meets the distribution network frequency modulation requirements. If so, the charging pile operates in a discharging mode, recalculate the estimated charging time, and obtain the revised estimated charging time;

[0029] If the revised estimated charging time is less than the allowed charging time, continue to discharge and continue to calculate the revised estimated charging time until the revised estimated charging time is equal to the allowed charging time.

[0030] In this solution, the formula for obtaining the charging / discharging cost is specifically as follows:

[0031] W = ∑ i (k i *T i *P i ) - ∑ j (k ′ j *T j *P j * η); where W represents the charging / discharging cost, k i represents the charging electricity price in the i-th period, k ′ j represents the discharging electricity price in the j-th period, T i represents the charging duration in the i-th period, T j represents the discharging duration in the j-th period, P i represents the charging power in the i-th period, P j represents the discharging power in the j-th period, and η represents the discharging efficiency coefficient.

[0032] In this solution, it further includes:

[0033] Based on a preset time period, obtain the temperature change rate of the electric vehicle battery;

[0034] Judge whether the temperature change rate of the electric vehicle battery is greater than a preset first temperature change threshold. If so, trigger a safety warning message;

[0035] If the temperature change rate of the electric vehicle battery is greater than a preset second temperature change threshold, then disconnect the charging connection between the electric vehicle and the charging pile microgrid.

[0036] The second aspect of the present invention provides a charging system for a distribution network peak shaving and frequency modulation charging pile microgrid, including a memory and a processor. A charging method program for a distribution network peak shaving and frequency modulation charging pile microgrid is stored in the memory. When the charging method program for a distribution network peak shaving and frequency modulation charging pile microgrid is executed by the processor, the following steps are implemented:

[0037] Obtain the final demand information of the user side, and obtain the factors and factor values of the current distribution network;

[0038] Based on a preset charging pile microgrid main control system, generate a charging / discharging plan according to the final demand information of the user side and the factor values of the current distribution network, and arrange the electric vehicles in the charging sequence;

[0039] Send the charging / discharging plan to the charging pile accessed by the electric vehicle. The preset charging / discharging controller in the charging pile charges / discharges the electric vehicle and measures the cost bidirectionally;

[0040] After charging is completed, the charge / discharge controller disconnects the switch, stops charging, obtains the charge / discharge fee, and sends the charge / discharge fee to the user terminal for display based on the microgrid platform;

[0041] The factors of the current distribution network at least include the current distribution network capacity, load period, and frequency; the final demand information at least includes the remaining power, the required charging amount, and the vehicle pick-up time.

[0042] In this solution, before generating the charge / discharge plan, it further includes:

[0043] Based on the required charging amount and the charging power of the corresponding charging pile, obtain the estimated charging time of the corresponding electric vehicle;

[0044] Obtain the current time, and based on the current time and the vehicle pick-up time, obtain the allowed charging time;

[0045] When the estimated charging time is greater than the allowed charging time, trigger a time-insufficient prompt message and send the time-insufficient prompt message to the user terminal for display;

[0046] When the estimated charging time is equal to the allowed charging time, directly charge the electric vehicle without generating a charge / discharge plan;

[0047] When the estimated charging time is less than the allowed charging time, generate a charge / discharge plan according to the final demand information of the user terminal and the factor values of the current distribution network.

[0048] In this solution, the steps of generating the charge / discharge plan specifically include:

[0049] Extract the durations of the peak, flat, and valley periods in the allowed charging time;

[0050] Judge whether the valley duration of the allowed charging time is longer than the estimated charging time. If the allowed charging time completely falls within the valley duration interval, the valley duration can be solely used for charging;

[0051] If the allowed charging time not only falls within the valley duration, then judge whether the valley and flat durations of the allowed charging time are longer than the estimated charging time. If the sum of the valley period and the flat period of the allowed charging time is greater than the estimated charging time, charge for all the valley durations and part of the flat duration;

[0052] If the allowed charging time spans three load periods, it is necessary to use all the valley and flat durations and add part of the peak duration for charging.

[0053] In this solution, it further includes:

[0054] Obtain the frequency of the current distribution network and the load period of the allowed charging time;

[0055] Determine the distribution network frequency range corresponding to the load period according to the load period allowing charging time;

[0056] If the frequency of the current distribution network is not within the distribution network frequency range corresponding to the load period, generate distribution network frequency modulation information;

[0057] Based on the distribution network frequency modulation information, obtain the remaining power of the electric vehicle;

[0058] Judge whether the remaining power of the electric vehicle meets the distribution network frequency modulation requirement. If so, the charging pile operates in the discharging mode, recalculate the estimated charging time, and obtain the revised estimated charging time;

[0059] If the revised estimated charging time is less than the allowed charging time, continue to discharge, and continue to calculate the revised estimated charging time until the revised estimated charging time is equal to the allowed charging time.

[0060] The present invention discloses a peak shaving and frequency modulation charging method and system for a distribution network peak shaving and frequency modulation charging pile microgrid. Based on the final demand information of the user side as the basic criterion, the present invention designs a reasonable charging scheme, which provides convenience for electric vehicle users and saves costs. Brief Description of the Drawings

[0061] Figure 1 Shows a flowchart of a peak shaving and frequency modulation charging method for a distribution network peak shaving and frequency modulation charging pile microgrid according to the present invention;

[0062] Figure 2 Shows a flowchart for determining a charging and discharging scheme;

[0063] Figure 3 Shows a flowchart of an electric vehicle during the charging process;

[0064] Figure 4 Shows the structure of a timing bidirectional charging and discharging intelligent charging pile microgrid system for peak shaving and frequency modulation of a distribution network according to the present invention;

[0065] Figure 5 Shows a charging system architecture diagram of the present invention;

[0066] Figure 6 Shows a block diagram of a peak shaving and frequency modulation charging pile microgrid charging system for a distribution network according to the present invention. Detailed Embodiments

[0067] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described in detail below with reference to the drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0068] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention may be practiced in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0069] Figure 1 The flowchart of a method for peak shaving and frequency modulation charging of electric vehicles in a distribution network charging pile microgrid according to the present invention is shown.

[0070] S101, Obtain the final demand information of the user side, and obtain the factors and factor values of the current distribution network;

[0071] S102, Based on the preset main control system of the charging pile microgrid, generate a charging / discharging plan according to the final demand information of the user side and the factor values of the current distribution network, and arrange the electric vehicles into the charging sequence;

[0072] S103, Send the charging / discharging plan to the charging pile accessed by the electric vehicle, and the preset charging / discharging controller in the charging pile charges / discharges the electric vehicle and measures the cost bidirectionally;

[0073] S104, After the charging is completed, the charging / discharging controller disconnects the switch, stops the charging, obtains the charging / discharging cost, and sends the charging / discharging cost to the user side based on the microgrid platform for display.

[0074] According to an embodiment of the present invention, the factors of the current distribution network at least include the current distribution network capacity, load period, and frequency; the final demand information at least includes the remaining power, the required charging amount, and the pick-up time; the electric vehicle intelligent system takes the charging amount and the pick-up time as the initial charging demand and informs the user through the human-vehicle interaction interface; the user adjusts and confirms the demand according to the expected usage situation, and the electric vehicle intelligent system submits the demand to the main control system of the charging pile microgrid platform; the initial demand is informed to the user through the human-vehicle interaction interface; the user opens the permission for the electric vehicle to discharge to the power grid, adjusts the demand information according to the expected next usage time and mileage, and confirms the final demand information including the remaining power, the required charging amount, and the pick-up time. The electric vehicle intelligent system submits the final charging demand to the main control system of the charging pile microgrid platform. It should be noted that the user can change and adjust the charging demand at any time through the human-machine interaction, and the microgrid platform needs to dynamically adjust the charging capacity according to the charging demand, update the capacity allocation plan of the entire microgrid in real time, and reflect it in the settlement of the ladder electricity price.

[0075] According to an embodiment of the present invention, before generating the charging / discharging plan, it further includes:

[0076] According to the required charging amount and the charging power of the corresponding charging pile, obtain the expected charging time of the corresponding electric vehicle;

[0077] Obtain the current time, and based on the current time and the vehicle pick-up time, obtain the allowed charging time;

[0078] When the predicted charging time is greater than the allowed charging time, trigger a time-insufficient prompt message and send the time-insufficient prompt message to the user terminal for display;

[0079] When the predicted charging time is equal to the allowed charging time, directly charge the electric vehicle without generating a charge / discharge plan;

[0080] When the predicted charging time is less than the allowed charging time, generate a charge / discharge plan according to the final demand information of the user terminal and the factor value of the current distribution network.

[0081] It should be noted that the required charging amount is the full charge value of the electric vehicle minus the current remaining charge value. Divide the required charging amount by the charging power of the corresponding charging pile to obtain the predicted charging time of the corresponding electric vehicle; when the time is insufficient, if the user terminal does not consider charging, it is not within the current consideration scope; if the user terminal considers charging, then charge immediately without participating in peak shaving and frequency modulation.

[0082] Figure 2 Shows the flowchart for determining the charge / discharge plan.

[0083] According to an embodiment of the present invention, the steps of generating the charge / discharge plan specifically include:

[0084] Extract the durations of the peak, flat, and valley periods in the allowed charging time;

[0085] Judge whether the valley duration of the allowed charging time is longer than the predicted charging time. If the allowed charging time completely falls within the interval of the valley duration, then the valley duration can be solely used for charging;

[0086] If the allowed charging time not only falls within the valley duration, then judge whether the sum of the valley and flat durations of the allowed charging time is longer than the predicted charging time. If the sum of the valley and flat periods of the allowed charging time is greater than the predicted charging time, then charge for all the valley durations and part of the flat duration;

[0087] If the allowed charging time spans three load periods, then it is necessary to use all the valley and flat durations and add part of the peak duration for charging.

[0088] It should be noted that the charging fees for the peak, flat, and valley periods in the allowed charging time are different. Therefore, give priority to the low-price charging periods. After all the low-price charging periods are fully utilized, then consider the high-price charging periods until the charging is completed.

[0089] According to an embodiment of the present invention, it further includes:

[0090] Obtain the frequency of the current power distribution network and the load period allowing the charging time;

[0091] Determine the power distribution network frequency range corresponding to the load period according to the load period allowing the charging time;

[0092] If the frequency of the current power distribution network is not within the power distribution network frequency range corresponding to the load period, generate power distribution network frequency modulation information;

[0093] Based on the power distribution network frequency modulation information, obtain the remaining power of the electric vehicle;

[0094] Judge whether the remaining power of the electric vehicle meets the power distribution network frequency modulation requirement. If so, the charging pile operates in the discharging mode, recalculate the estimated charging time, and obtain the revised estimated charging time;

[0095] If the revised estimated charging time is less than the allowed charging time, continue to discharge, and continue to calculate the revised estimated charging time until the revised estimated charging time is equal to the allowed charging time.

[0096] It should be noted that the main control system of the charging pile microgrid platform reads the information submitted by the electric vehicle intelligent system to judge whether the remaining power is sufficient to participate in frequency modulation. If the remaining power of the vehicle is insufficient and it is not suitable to participate in frequency modulation, the vehicle does not feed back power and charges according to the determined charge-discharge plan; if the remaining power of the vehicle is sufficient and the permission to participate in frequency modulation is open, the charging pile operates in the discharging mode, injects the electric energy in the electric vehicle into the charging pile microgrid, and feeds it into the power distribution network through the PCC (Point of Common Coupling); when the charging pile microgrid participates in power distribution network frequency modulation and the charging piles in the microgrid operate in the discharging mode, each electric vehicle participating in power distribution network frequency modulation needs to continuously judge whether the estimated charging time can meet the charging requirement according to its own power. If continuous discharging can meet the charging requirement, continue to discharge; if continuous discharging, the estimated actual charging time can no longer meet the charging requirement, stop discharging.

[0097] According to the embodiments of the present invention, the formula for obtaining the charge / discharge cost is specifically:

[0098] W = ∑ i (k i *T i *P i ) - ∑ j (k ′ j *T j *P j *η); where W represents the charge / discharge cost, k i represents the charging electricity price in the i-th period, k ′ j represents the discharging electricity price in the j-th period, T i represents the charging duration in the i-th period, Tj represents the discharge duration in the j-th period, P i represents the charging power in the i-th period, P j represents the discharge power in the j-th period, and η represents the discharge efficiency coefficient.

[0099] It should be noted that during the charging and discharging process of the electric vehicle, the electric energy released or absorbed during charging and discharging is settled according to their respective stepped electricity prices. Further, the user can change and adjust the charging demand at any time through human-computer interaction, and the microgrid platform will increase or decrease the charging and discharging power of the electric vehicle according to constraints such as the charging demand, the charging / discharging power of the electric vehicle, and the maintenance of the energy storage components of the electric vehicle, so as to obtain the best economic benefits while meeting the charging demand.

[0100] According to an embodiment of the present invention, it further includes:

[0101] Based on a preset time period, obtain the temperature change rate of the electric vehicle battery;

[0102] Judge whether the temperature change rate of the electric vehicle battery is greater than a preset first temperature change threshold. If so, trigger a safety warning message;

[0103] If the temperature change rate of the electric vehicle battery is greater than a preset second temperature change threshold, then disconnect the charging connection between the electric vehicle and the charging pile microgrid.

[0104] It should be noted that during the charging process of the electric vehicle, the temperature of the electric vehicle will increase during the charging process. In order to ensure charging safety, two temperature sensing limits are set.

[0105] According to an embodiment of the present invention, it further includes: when multiple electric vehicles request frequency modulation services at the same time, select the batteries of the electric vehicles to participate in discharge in descending order of battery health; when the number of frequency modulation services reaches a set number threshold, stop the electric vehicles from participating in frequency modulation services.

[0106] According to an embodiment of the present invention, it further includes

[0107] Obtain the carbon emission intensity C during the charging process of the electric vehicle, and its formula is where P t represents the charging power in the t-th period, η t represents the power transmission efficiency in the t-th period, and f represents the carbon emission factor of the power grid in the t-th period;

[0108] Obtain the carbon emission reduction amount C during the discharge process of the electric vehicle ′ , and its formula is where p ′ t represents the discharge power in the t-th period, η ′t represents the discharge efficiency during period t, f ′ represents the carbon emission reduction amount avoided per 1 kWh of discharge during period t;

[0109] Subtract the carbon emission intensity during the charging process of the electric vehicle from the carbon emission reduction amount during the discharging process of the electric vehicle to obtain the carbon credits that the user can dispose of;

[0110] Multiply the carbon credits that the user can dispose of by a preset price coefficient to obtain the deductible charging fee, and revise the charging / discharging fee according to the deductible charging fee.

[0111] Figure 3 Shows the flowchart of the charging process of the electric vehicle.

[0112] As Figure 3 shown, after the electric vehicle is connected to the charging pile, the user inputs the preliminary charging requirements on the interaction interface and confirms them to obtain the final requirement information; when the allowed charging time meets the preset charging time, further confirm whether the allowed charging time is longer than the expected charging time. If not, charge immediately and do not participate in peak shaving and frequency modulation; the charging with the optimal timing scheme is the charging / discharging scheme generated according to the final requirement information of the user side and the factor values of the current distribution network.

[0113] Figure 4 Shows the structure of the timing bidirectional charging and discharging intelligent charging pile microgrid system for peak shaving and frequency modulation of the distribution network of the present invention.

[0114] As Figure 4 shown, a bidirectional charging and discharging intelligent charging pile microgrid system for peak shaving and frequency modulation of the distribution network provided by the present invention is connected to the public distribution network with a single-point or multi-point PCC. An electric energy quality monitoring device and a bidirectional metering device are installed at the PCC. Each charging pile is sequentially connected to the microgrid bus. The main control system of the charging pile microgrid platform establishes a communication connection with each charging pile, uniformly manages each charging pile, and establishes an information connection with the human-computer interaction module of the electric vehicle intelligent system; among them, the microgrid is an AC microgrid or a DC microgrid, and the voltage level depends on specific requirements; the microgrid topology structure includes but is not limited to the following methods: star network, chain network, ring network, etc.; the microgrid can be connected to other power supply points, such as a photovoltaic system or a wind power generation system arranged on the shed roof.

[0115] Figure 5 Shows the architecture diagram of the charging system of the present invention.

[0116] As Figure 5As shown in the figure, the charging system architecture of the present invention includes an electric vehicle intelligent system, a main control system of a charging pile microgrid platform, a charging pile, a charge / discharge controller, and a two-way metering and settlement device. Among them, the electric vehicle intelligent system is connected to the main control system of the charging pile microgrid platform through a human-computer interaction method, and the human-computer interaction method includes but is not limited to the following methods: software connection between the electric vehicle operation platform and the charging pile microgrid platform, mobile phone APP connection, connection of other electronic terminals, etc. The main control system of the charging pile microgrid platform can obtain information such as the current distribution network frequency and load through a dispatching and distribution network data system. The main control system of the charging pile microgrid platform is connected to the charging pile controller. The charging pile is respectively connected to the charge / discharge controller and the two-way metering and settlement device. The charging pile guides the charging and discharging and corresponding power of the charge / discharge controller to complete the implementation of the charging plan. The charge / discharge controller controls the charge / discharge circuit to complete the injection or extraction of the electric energy of the electric vehicle energy storage element into the distribution network. The two-way metering and settlement device measures the charging and discharging energy, settles according to the electricity price difference between the peak or trough period of the load, and then feeds the metering data back to the main control system of the charging pile microgrid platform for power trading. The charging pile body includes a display module for displaying the charging and discharging power, real-time current, stepped electricity charges, and settlement methods. Considering that the charge / discharge current is relatively large and there are risks in the process, the charging pile and the charge / discharge controller include corresponding relay protection devices.

[0117] Figure 6 The block diagram of a peak shaving and frequency modulation charging pile microgrid charging system of the present invention is shown.

[0118] As Figure 6 As shown in the figure, in the second aspect of the present invention, a peak shaving and frequency modulation charging pile microgrid charging system 6 is provided, including a memory 61 and a processor 62. A peak shaving and frequency modulation charging pile microgrid charging method program is stored in the memory. When the peak shaving and frequency modulation charging pile microgrid charging method program is executed by the processor, the following steps are implemented:

[0119] Obtain the final demand information of the user side, and obtain the factors and factor values of the current distribution network;

[0120] Based on the preset main control system of the charging pile microgrid, generate a charge / discharge plan according to the final demand information of the user side and the factor values of the current distribution network, and arrange the electric vehicle into the charging sequence;

[0121] Send the charge / discharge plan to the charging pile accessed by the electric vehicle. The preset charge / discharge controller in the charging pile charges and discharges the electric vehicle and performs two-way metering of the fees;

[0122] After the charging is completed, the charge / discharge controller disconnects the switch, stops charging, obtains the charge / discharge fee, and sends the charge / discharge fee to the user side based on the microgrid platform for display;

[0123] The factors of the current distribution network at least include the current distribution network capacity, load period, and frequency; the final demand information at least includes the remaining power, the required charging amount, and the vehicle pick-up time.

[0124] In this solution, before generating the charging / discharging plan, it further includes:

[0125] Based on the required charging amount and the charging power of the corresponding charging pile, obtain the estimated charging time of the corresponding electric vehicle;

[0126] Obtain the current time, and based on the current time and the vehicle pick-up time, obtain the allowable charging time;

[0127] When the estimated charging time is greater than the allowable charging time, trigger a time-insufficient prompt message and send the time-insufficient prompt message to the user terminal for display;

[0128] When the estimated charging time is equal to the allowable charging time, directly charge the electric vehicle without generating a charging / discharging plan;

[0129] When the estimated charging time is less than the allowable charging time, generate a charging / discharging plan according to the final demand information of the user terminal and the factor values of the current distribution network.

[0130] In this solution, the steps of generating the charging / discharging plan specifically include:

[0131] Extract the durations of the peak, flat, and low valleys in the allowable charging time;

[0132] Judge whether the low valley duration of the allowable charging time is longer than the estimated charging time. If the allowable charging time completely falls within the interval of the low valley duration, the low valley duration can be solely used for charging;

[0133] If the allowable charging time not only falls within the low valley duration, then judge whether the low valley and flat duration of the allowable charging time are longer than the estimated charging time. If the sum of the low valley period and the flat period of the allowable charging time is greater than the estimated charging time, charge for all the low valley durations and part of the flat duration;

[0134] If the allowable charging time spans three load periods, it is necessary to use all the low valley and flat durations and add part of the peak duration for charging.

[0135] In this solution, it further includes:

[0136] Obtain the frequency of the current distribution network and the load period of the allowable charging time;

[0137] According to the load period of the allowable charging time, determine the distribution network frequency range corresponding to the load period;

[0138] If the frequency of the current power distribution network is not within the power distribution network frequency range of the corresponding load period, power distribution network frequency modulation information is generated;

[0139] Based on the power distribution network frequency modulation information, the remaining power of the electric vehicle is obtained;

[0140] It is judged whether the remaining power of the electric vehicle meets the power distribution network frequency modulation requirement. If so, the charging pile operates in a discharging mode, and the estimated charging time is recalculated to obtain a revised estimated charging time;

[0141] If the revised estimated charging time is less than the allowable charging time, continue to discharge, and continue to calculate the revised estimated charging time until the revised estimated charging time is equal to the allowable charging time.

[0142] The present invention discloses a method and system for peak shaving and frequency modulation charging of a power distribution network charging pile. The present invention takes the final demand information of the user side as the basic criterion, designs a reasonable charging scheme, provides convenience for electric vehicle users, and saves costs.

[0143] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined, or can be integrated into another system, or some features can be ignored, or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed with each other can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical, or other forms.

[0144] The units described above as separate components may or may not be physically separated, and the components shown as units may or may not be physical units; they can be located in one place or distributed to multiple network units; some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0145] In addition, each functional unit in the embodiments of the present invention can be all integrated in one processing unit, or each unit can be separately used as one unit, or two or more units can be integrated in one unit; the above integrated units can be implemented in the form of hardware, or in the form of hardware plus software functional units.

[0146] Those of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps including those of the above method embodiments. The aforementioned storage medium includes various media that can store program codes, such as removable storage devices, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs.

[0147] Alternatively, if the above integrated unit of the present invention is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the embodiments of the present invention, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media that can store program codes, such as removable storage devices, ROM, RAM, magnetic disks, or optical discs.

Claims

1. A distribution network peak-shaving and frequency-regulating charging pile microgrid charging method, characterized in that: include: Obtain the final demand information of the user end, and obtain the factors and factor values ​​of the current distribution network; Based on the preset charging pile microgrid master control system, a charging / discharging plan is generated according to the final demand information of the user end and the factor value of the current distribution network, and the electric vehicles are arranged into the charging sequence; The charging / discharging plan is sent to the charging pile to which the electric vehicle is connected. The preset charging / discharging controller in the charging pile charges / discharges the electric vehicle and measures the charges in both directions. After charging is completed, the charge / discharge controller disconnects the switch, stops charging, obtains the charge / discharge fee, and sends the charge / discharge fee to the user end for display based on the microgrid platform; The factors of the current distribution network include at least the current distribution network capacity, load period and frequency; The final demand information includes at least the remaining power, the required charging amount and the vehicle pick-up time.

2. A distribution network peak-shaving and frequency-regulating charging pile microgrid charging method according to claim 1, characterized in that: Before generating the charge / discharge plan, the method further includes: According to the required charging amount and the charging power of the corresponding charging pile, the estimated charging time of the corresponding electric vehicle is obtained; Get the current time, and get the allowed charging time based on the current time and the vehicle pick-up time; When the estimated charging time is greater than the allowed charging time, a prompt message indicating that the time is insufficient is triggered, and the prompt message indicating that the time is insufficient is sent to the user terminal for display; When the estimated charging time is equal to the allowed charging time, the electric vehicle is directly charged without generating a charging / discharging plan; When the estimated charging time is less than the allowed charging time, a charging / discharging plan is generated according to the final demand information of the user end and the factor values ​​of the current distribution network.

3. A distribution network peak-shaving and frequency-regulating charging pile microgrid charging method according to claim 1 or 2, characterized in that: The step of generating a charge / discharge plan specifically includes: Extract the duration of peak, flat and valley periods in the allowed charging time; Determine whether the valley duration of the allowed charging time is longer than the estimated charging time. If the allowed charging time completely falls within the valley duration range, the valley duration can be used alone for charging. If the allowed charging time does not only fall within the valley time, then determine whether the valley and flat time periods of the allowed charging time are longer than the expected charging time. If the sum of the valley time period and the flat time period of the allowed charging time is greater than the expected charging time, then charge for all valley time periods and part of the flat time period. If the charging time is allowed to span three load periods, it is necessary to utilize all the time during the valley and flat periods and add the peak time to charge.

4. A distribution network peak-shaving and frequency-regulating charging pile microgrid charging method according to claim 1, characterized in that: Also includes: Get the frequency of the current distribution network and the load period of the allowed charging time; According to the load period of the allowed charging time, determine the distribution network frequency range corresponding to the load period; If the current distribution network frequency is not within the distribution network frequency range of the corresponding load period, the distribution network frequency modulation information is generated; Based on the frequency modulation information of the distribution network, the remaining power of the electric vehicle is obtained; Determine whether the remaining power of the electric vehicle meets the frequency regulation requirements of the distribution network. If so, the charging pile operates in a discharge mode, and the estimated charging time is recalculated to obtain a revised estimated charging time; If the revised estimated charging time is less than the allowed charging time, discharge continues and the revised estimated charging time continues to be calculated until the revised estimated charging time is equal to the allowed charging time.

5. A distribution network peak-shaving and frequency-regulating charging pile microgrid charging method according to claim 1, characterized in that: The formula for obtaining the charge / discharge cost is specifically: W=∑ i (k i *T i *P i )―∑ j (k ′ j *T j *P j *η); where W represents the charge / discharge cost, k i represents the charging electricity price in period i, k ′ j represents the discharge price in period j, T i represents the charging time of period i, T j represents the discharge duration of period j, P i represents the charging power in period i, P j represents the discharge power in period j, and η represents the discharge efficiency coefficient.

6. A distribution network peak-shaving and frequency-regulating charging pile microgrid charging method according to claim 1, characterized in that: Also includes: Based on a preset time period, obtain the temperature change rate of the electric vehicle battery; Determine whether the temperature change rate of the electric vehicle battery is greater than a preset first temperature change threshold, and if so, trigger a safety warning message; If the temperature change rate of the battery of the electric vehicle is greater than a preset second temperature change threshold, the charging connection between the electric vehicle and the charging pile microgrid is disconnected.

7. A distribution network peak-shaving and frequency-regulating charging pile microgrid charging system, characterized in that: The invention comprises a memory and a processor, wherein the memory stores a distribution network peak-shaving and frequency-regulating charging pile microgrid charging method program, and when the distribution network peak-shaving and frequency-regulating charging pile microgrid charging method program is executed by the processor, the following steps are implemented: Obtain the final demand information of the user end, and obtain the factors and factor values ​​of the current distribution network; Based on the preset charging pile microgrid master control system, a charging / discharging plan is generated according to the final demand information of the user end and the factor value of the current distribution network, and the electric vehicles are arranged into the charging sequence; The charging / discharging plan is sent to the charging pile to which the electric vehicle is connected. The preset charging / discharging controller in the charging pile charges / discharges the electric vehicle and measures the charges in both directions. After charging is completed, the charge / discharge controller disconnects the switch, stops charging, obtains the charge / discharge fee, and sends the charge / discharge fee to the user end for display based on the microgrid platform; The factors of the current distribution network include at least the current distribution network capacity, load period and frequency; The final demand information includes at least the remaining power, the required charging amount and the vehicle pick-up time.

8. A distribution network peak-shaving and frequency-regulating charging pile microgrid charging system according to claim 7, characterized in that: Before generating the charge / discharge plan, the method further includes: According to the required charging amount and the charging power of the corresponding charging pile, the estimated charging time of the corresponding electric vehicle is obtained; Get the current time, and get the allowed charging time based on the current time and the vehicle pick-up time; When the estimated charging time is greater than the allowed charging time, a prompt message indicating that the time is insufficient is triggered, and the prompt message indicating that the time is insufficient is sent to the user terminal for display; When the estimated charging time is equal to the allowed charging time, the electric vehicle is directly charged without generating a charging / discharging plan; When the estimated charging time is less than the allowed charging time, a charging / discharging plan is generated according to the final demand information of the user end and the factor values ​​of the current distribution network.

9. A distribution network peak-shaving and frequency-regulating charging pile microgrid charging system according to claim 7 or 8, characterized in that: The step of generating a charge / discharge plan specifically includes: Extract the duration of peak, flat and valley periods in the allowed charging time; Determine whether the valley duration of the allowed charging time is longer than the estimated charging time. If the allowed charging time completely falls within the valley duration range, the valley duration can be used alone for charging. If the allowed charging time does not only fall within the valley time, then determine whether the valley and flat time periods of the allowed charging time are longer than the expected charging time. If the sum of the valley time period and the flat time period of the allowed charging time is greater than the expected charging time, then charge for all valley time periods and part of the flat time period. If the charging time is allowed to span three load periods, it is necessary to utilize all the time during the valley and flat periods and add the peak time to charge.

10. A distribution network peak-shaving and frequency-regulating charging pile microgrid charging system according to claim 7, characterized in that: Also includes: Get the frequency of the current distribution network and the load period of the allowed charging time; According to the load period of the allowed charging time, determine the distribution network frequency range corresponding to the load period; If the current distribution network frequency is not within the distribution network frequency range of the corresponding load period, the distribution network frequency modulation information is generated; Based on the frequency modulation information of the distribution network, the remaining power of the electric vehicle is obtained; Determine whether the remaining power of the electric vehicle meets the frequency regulation requirements of the distribution network. If so, the charging pile operates in a discharge mode, and the estimated charging time is recalculated to obtain a revised estimated charging time; If the revised estimated charging time is less than the allowed charging time, discharge continues and the revised estimated charging time continues to be calculated until the revised estimated charging time is equal to the allowed charging time.

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