V2G-based diesel-storage hybrid emergency power supply system and control method thereof

Abstract

The invention provides a V2G-based diesel-storage hybrid emergency power supply system and a control method thereof, and is applied to the technical field of emergency power supplies, the V2G-based diesel-storage hybrid emergency power supply system comprises a vehicle system, an energy storage system and a diesel-generator system, the emergency power supply system comprises a grid-connected economic mode and an off-grid emergency mode, when a power grid state is normal, the emergency power supply system operates in the grid-connected economic mode, and when the power grid state is normal, the emergency power supply system operates in the off-grid emergency mode corresponding grid-connected strategies are executed according to the conditions of the vehicle system and the energy storage system, and economic benefits are earned through the vehicle system and the energy storage system on the basis that it is guaranteed that the energy storage system has the emergency capacity; when the power grid state is abnormal, the emergency power supply system operates in an off-grid emergency mode, corresponding emergency strategies are executed according to the conditions of the vehicle system and the energy storage system, and the use frequency of the diesel generator system is reduced on the basis of guaranteeing load power supply. The defects of a traditional toll station and other outer suburb power distribution load emergency scheme are overcome, more efficient, clean and intelligent power supply and emergency guarantee are achieved, and the stability and reliability of a power distribution system are enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of emergency power supplies, and particularly relates to a V2G-based diesel-storage hybrid emergency power supply system and its control method. Background Art

[0002] In traditional power distribution systems such as toll stations, the power distribution reliability is not high, but the load is particularly important. Diesel generators (DG) are often used in combination with UPS (uninterruptible power supply) as an emergency power supply solution. However, DGs have disadvantages such as high noise, serious emission pollution, high maintenance costs, and slow start-up response; although the UPS can provide short-term uninterrupted power supply, its energy storage capacity is limited and it is difficult to maintain the operation of high-power loads for a long time. Conventional industrial and commercial energy storage cabinets can also be used as backup power, but their functions are single and their endurance is limited in extreme scenarios; with the rapid development of new energy vehicle technology, its potential as a mobile energy storage carrier has gradually emerged, and at the same time, new energy storage technologies have provided new ideas for emergency power supply. At present, the new energy vehicle V2G technology is still in its infancy. How to use these new technologies to build an efficient, clean, and intelligent power distribution emergency system has become an urgent problem to be solved. Summary of the Invention

[0003] In view of the above problems in the prior art, the purpose of the present invention is to provide a V2G-based diesel-storage hybrid emergency power supply system, which solves the deficiencies of the emergency power supply solutions for remote suburban power distribution loads such as traditional toll stations, realizes more efficient, clean, and intelligent power supply and emergency guarantee, and enhances the stability and reliability of the power distribution system.

[0004] A V2G-based diesel-storage hybrid emergency power supply system includes a vehicle system, an energy storage system, and a DG system. The emergency power supply system includes a grid-connected economic mode and an off-grid emergency mode. When the grid state is normal, the emergency power supply system operates in the grid-connected economic mode, and executes corresponding grid connection strategies according to the situations of the vehicle system and the energy storage system. On the basis of ensuring that the energy storage system has emergency capacity, economic benefits are earned by using the vehicle system and the energy storage system; when the grid state is abnormal, the emergency power supply system operates in the off-grid emergency mode, and executes corresponding emergency strategies according to the situations of the vehicle system and the energy storage system. On the basis of ensuring load power supply, the use frequency of the DG system is reduced.

[0005] Preferably, it further includes an energy management system for real-time collecting the grid state, the state of the energy storage system, the vehicle information of the vehicle system, and the required power of the load; the energy management system controls the charging and discharging timing and charging and discharging power of the energy storage system, coordinates the charging and discharging processes of new energy vehicles based on the V2G interaction module, manages the start and stop of the DG system, and power distribution based on the collected information.

[0006] Preferably, the vehicle system includes a V2G interaction module and an externally connected new energy vehicle, and the energy management system realizes information interaction with the new energy vehicle through the V2G interaction module; The vehicle system includes an economic mode and an emergency mode. When the vehicle system is in the economic mode, the new energy vehicle is connected to the power grid, and economic benefits are earned through the charging and discharging of the vehicle battery; when the vehicle system is in the emergency mode, the new energy vehicle is connected to the load, and the normal operation of the load is supported by the discharge of the vehicle battery.

[0007] Preferably, the energy storage system includes an energy storage battery module and an energy storage inverter module, and the energy storage inverter module is used to realize the AC-DC conversion between the energy storage battery and the power grid or between the energy storage battery and the load; The energy storage system includes an economic mode, an emergency mode and a standby mode. When the energy storage system is in the economic mode, the energy storage system is connected to the power grid, and economic benefits are earned through the charging and discharging of the energy storage battery; when the energy storage system is in the emergency mode, the energy storage system is connected to the load, and the normal operation of the load is supported by the discharge of the energy storage battery; when the energy storage system is in the standby mode, the energy storage system is connected to the power grid and waits for charging.

[0008] Preferably, the diesel generator system includes a diesel power generation module. The diesel generator system includes an emergency mode and a standby mode. Under normal circumstances, the diesel generator system is in the standby mode. When the power grid is abnormal and the energy storage system meets the diesel generator power supply conditions, the diesel generator system enters the emergency mode and supplies power to the load, the energy storage battery and the vehicle battery as an emergency power source.

[0009] Preferably, a grid interaction module is configured between the load and the power grid. The grid interaction module includes a static transfer switch STS, and the static transfer switch STS is used to realize the switching of the load power supply. When the power grid is abnormal, the load power supply is switched to the emergency power supply system.

[0010] Another object of the invention is to provide a control method for a V2G-based diesel-electric hybrid emergency power supply system. The emergency power supply system includes a vehicle system, an energy storage system, a diesel generator system and an energy management system. The control method includes the following steps: Step 1, monitor the power grid status in real time and switch the corresponding operating mode according to the power grid status; the operating modes of the emergency power supply system include a grid-connected economic mode and an off-grid emergency mode; Step 2, when the emergency power supply system is in the grid-connected economic mode, dynamically execute the corresponding grid-connected strategy according to the vehicle system information and the energy storage system parameters: When the energy storage system meets the grid connection conditions, the energy storage system enters the economic mode and executes Grid Connection Strategy 1 to enable the energy storage battery to charge and discharge independently; when the energy storage system does not meet the grid connection conditions, the energy storage system enters the standby mode and waits for charging; When the energy storage system is in the standby mode, if a new energy vehicle is connected, the vehicle system enters the economic mode and executes grid connection strategy II, enabling the new energy vehicle battery to charge and discharge independently. When the energy storage system is in the economic mode, if a new energy vehicle is connected, the vehicle system enters the economic mode, forming a vehicle-storage grid-connected system with the coordinated action of the vehicle system and the energy storage system, and executes grid connection strategy III, enabling the energy storage battery and the vehicle battery to charge and discharge in coordination. Step 3: When the emergency power supply system is in the off-grid emergency mode, dynamically execute corresponding emergency strategies according to the energy storage system parameters and the vehicle system conditions: When the energy storage system meets the diesel generator power supply conditions, trigger the diesel generator system to enter the emergency mode, and as the emergency power supply, execute emergency strategy I, enabling the diesel generator system to supply power to the load, the energy storage battery, and the vehicle battery. If the energy storage system does not meet the diesel generator power supply conditions, the energy storage system enters the emergency mode, and as the emergency power supply, executes emergency strategy II, enabling the energy storage battery to supply power to the load and realizing the coordinated interaction of the storage-load system. When the energy storage system is in the emergency mode, if a new energy vehicle is connected, the vehicle system is enabled to enter the emergency mode, forming a vehicle-storage emergency power supply, and executes emergency strategy III, enabling the energy storage battery and the vehicle battery to supply power to the load in coordination and realizing the coordinated interaction of the vehicle-storage-load system.

[0011] Preferably, when the emergency power supply system forms a vehicle-storage grid-connected system and executes grid connection strategy III, the coordination process of the energy storage battery and the vehicle battery charging and discharging in coordination is as follows: Calculate the dischargeable time of the vehicle battery according to the agreed parameters and vehicle information ; The agreed parameters include the discharge ratio coefficient , the planned exit time, and the planned exit capacity ; Among them, the calculation formula of the dischargeable time is as follows:

[0012]

[0013] In the formula, is the available capacity of the vehicle battery, is the remaining capacity of the vehicle battery when the vehicle is connected, is the discharge ratio coefficient, is the current supplied power, is the average discharge power of the vehicle battery, is the efficiency; Dynamically calculate the discharge power of the energy storage battery , the discharge power of the vehicle battery , and discharge in coordination; the calculation formula is as follows:

[0014]

[0015] Among them, is the available capacity of the vehicle battery, is the total capacity of the energy storage battery, is the discharge ratio coefficient, is the real-time power on the grid side, is the real-time power on the load side, is the grid support coefficient; After the discharge is completed, calculate the charging power of the vehicle battery according to the agreed parameters and vehicle information , and the calculation process is as follows:

[0016]

[0017] In the formula, is the required compensation capacity, is the planned withdrawal capacity, is the currently supplied power, is the remaining connection time of the vehicle, the maximum charging power of the vehicle battery; When the vehicle access time reaches the planned withdrawal time, the vehicle withdraws and settles the economic benefits; After the vehicle withdraws, the emergency power supply system continues to dynamically execute the corresponding grid connection strategy by monitoring the vehicle system information and energy storage system parameters.

[0018] Preferably, when the emergency power supply system forms a vehicle-energy storage emergency power supply and executes emergency strategy three, enabling the energy storage battery and the vehicle battery to jointly supply power to the load and realizing the coordinated interaction of the vehicle-energy storage-load system, based on the principle of maximizing vehicle utilization, the vehicle battery is used as the main power supply, the energy storage battery is used as the auxiliary power supply, the compensable power of the vehicle battery is preferentially used, and then the energy storage battery is used to supplement the remaining load demand.

[0019] Preferably, the specific process of the emergency power supply system forming a vehicle-energy storage emergency power supply and executing emergency strategy three, enabling the energy storage battery and the vehicle battery to jointly supply power to the load and realizing the coordinated interaction of the vehicle-energy storage-load system is as follows: Calculate the remaining connection time of the vehicle and the available capacity of the vehicle battery according to the agreed parameters and vehicle information, and the calculation formula is as follows:

[0020] In the formula, is the remaining capacity of the vehicle battery when the vehicle is connected, is the discharge proportion coefficient; Dynamically calculate the emergency discharge power of the vehicle battery , and perform discharge based on the emergency discharge power , and the calculation formula is as follows:

[0021] In the formula, is the remaining connection time of the vehicle, is the available capacity of the vehicle battery, is the maximum discharge power of the vehicle battery; After the vehicle battery finishes discharging, it enters the standby state, and the energy storage battery performs the discharge operation to support the load operation; when the vehicle access time does not reach the planned exit time and the vehicle battery is in the standby state, if the power grid returns to the normal state, then charge through the power grid to make its battery capacity reach the planned exit capacity ; if the diesel generator system is started, then charge through the diesel generator system to make its battery capacity reach the planned exit capacity ; Among them, the calculation process of the charging power is as follows:

[0022]

[0023] In the formula, is the required compensation capacity, is the planned exit capacity, is the currently supplied power, is the remaining connection time of the vehicle, the maximum charging power of the vehicle battery; When the vehicle access time reaches the planned exit time, the vehicle exits and settles the economic benefits; After the vehicle exits, the emergency power supply system continues to dynamically execute corresponding emergency strategies according to the energy storage system parameters and the vehicle system conditions.

[0024] The beneficial effects of the present invention are: the V2G-based diesel-electric hybrid emergency power supply system and its control method can execute corresponding grid connection strategies and emergency strategies according to different states of the power grid. In the grid-connected economic mode, corresponding economic benefits can be earned through the charge and discharge operations of the vehicle battery and the energy storage battery; in the off-grid emergency mode, on the basis of ensuring the load requirements of the station, the use frequency of the diesel generator system can be reduced by 60%-80%, improving the energy utilization efficiency, realizing more efficient, clean and intelligent power supply and emergency guarantee, and enhancing the stability and reliability of the distribution system.

[0025] Furthermore, the system constructs a V2G-diesel storage collaborative control architecture. By using the V2G technology of new energy vehicles, new energy vehicles can be continuously connected according to the load demand in the off-grid scenario. Through the dynamic power distribution algorithm, the real-time power optimization of multiple energy sources can be achieved, and the off-grid endurance time can be extended by 2-3 times, improving the intelligent level of the entire distribution system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation to the present invention. In the drawings: Figure 1 is a schematic structural diagram of a V2G-based diesel storage hybrid emergency power supply system of the present invention; Figure 2 is a flowchart of the V2G request access interaction of the present invention; Figure 3 is a flowchart of the control method of the V2G-based diesel storage hybrid emergency power supply system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Embodiment 1 As Figure 1 shown, a V2G-based diesel storage hybrid emergency power supply system includes a vehicle system, a energy storage system, a diesel generator system, and an energy management system. The emergency power supply system includes a grid-connected economic mode and an off-grid emergency mode. When the grid status is normal, the emergency power supply system operates in the grid-connected economic mode and executes corresponding grid-connected strategies according to the vehicle system and the energy storage system. On the basis of ensuring that the energy storage system has emergency capacity, economic benefits are earned by using the vehicle system and the energy storage system. When the grid status is abnormal, the emergency power supply system operates in the off-grid emergency mode and executes corresponding emergency strategies according to the vehicle system and the energy storage system. On the basis of ensuring load power supply, the use frequency of the diesel generator system is reduced.

[0028] Among them, the energy management system is used to collect data such as the grid status, the status of the energy storage system, the vehicle information of the vehicle system, and the demand power of the load in real time, and intelligently control the operation of each system based on the collected information. Specifically, the energy management system is used to control the charging and discharging timing and power of the energy storage system, to coordinate the charging and discharging process of new energy vehicles based on the V2G interaction module, and to manage the start and stop and power distribution of the diesel generator system.

[0029] As Figure 2 shown, the vehicle system includes a V2G interaction module and an externally connected new energy vehicle. The energy management system realizes information interaction with the new energy vehicle through the V2G interaction module.

[0030] When the emergency management system operates in the grid-connected economic mode, after the new energy vehicle is connected, it enters the economic mode according to the instructions issued by the energy management system, and performs charging and discharging operations according to the vehicle parameters to earn economic benefits.

[0031] When the emergency management system operates in the off-grid emergency mode, after the new energy vehicle is connected, it enters the emergency mode according to the instructions issued by the energy management system, and performs discharging operations according to the vehicle parameters to earn economic benefits.

[0032] The energy storage system includes an energy storage battery module and an energy storage converter module. The energy storage converter module is a bidirectional current controllable conversion device connecting the energy storage battery module and the power grid, which can accurately adjust the power grid, frequency, and power between the power grid and the energy storage battery module, realizing constant power and constant current charging and discharging and smoothing the output of fluctuating power sources.

[0033] The energy storage system includes an economic mode, an emergency mode, and a standby mode, and switches the operating mode according to the instructions issued by the energy management system based on the power grid status. When the energy storage system is in the economic mode, on the basis of ensuring the emergency capacity requirements, charging and discharging operations of the energy storage battery are carried out to obtain economic benefits; when the energy storage system is in the emergency mode, on the basis of ensuring the safety capacity, it serves as an emergency power supply to supply power to the load.

[0034] The diesel generator system includes a diesel power generation module. In the case of abnormal power grid status, when the power of the energy storage battery in the energy storage system is insufficient, the diesel power generation module is seamlessly connected to the power consumption system as an emergency power supply to supply power and ensure the power supply within the station.

[0035] When the diesel generator supplies power, on the one hand, it supports the operation of the load, and on the other hand, it uses the remaining power to charge the energy storage system and the vehicle system. Among them, the charging priority of the energy storage system is higher than that of the vehicle system. When the power of the energy storage system reaches the threshold, the diesel generator stops supplying power, and the energy storage system supports the operation of the load. After the power grid returns to normal, it seamlessly switches to the power grid power supply mode.

[0036] In addition, a power grid interaction module is configured between the station load and the power grid. The power grid interaction module is configured with a static transfer switch STS, and through the static transfer switch STS, millisecond-level seamless switching between the commercial power (i.e., the power grid) and the emergency power supply can be realized. When the power grid status is abnormal, through the static transfer switch, the power supply of the station load can be switched to the emergency power supply system within milliseconds to ensure that the entire station does not lose power and users are unaware; after the power grid status is restored, it seamlessly switches back to the power grid power supply. In addition, the power grid interaction module is configured with a bypass switch (bidirectional power switch BPS) for maintenance.

[0037] Embodiment 2 As Figure 3As shown in the figure, the second aspect of the present invention proposes a control method for a diesel - energy storage hybrid emergency power supply system based on V2G, which is used to control the diesel - energy storage hybrid emergency power supply system based on V2G as described in Embodiment 1, and includes the following steps: Step 1: Monitor the grid status in real - time and switch the corresponding operating mode according to the grid status.

[0038] If the grid status is normal, the emergency power supply system operates in the grid - connected economic mode; if the grid status is abnormal, the emergency power supply system switches to the off - grid emergency mode.

[0039] Among them, the grid status is judged by the grid voltage and the grid frequency. The standard value of the grid voltage is set as , and the standard value of the grid frequency is f. When the value of the grid voltage is within the range of ±10%, and the value of the grid frequency is within the range of f±1%, the grid is in a normal state; otherwise, the grid is in an abnormal state.

[0040] Step 2: When the emergency power supply system is in the grid - connected economic mode, the station load is powered by the grid, and the emergency power supply system dynamically executes the corresponding grid - connection strategy according to the vehicle system information and the energy storage system parameters.

[0041] The specific steps are as follows: 2.1 Judge whether the SOC of the energy storage battery in the energy storage system is greater than Threshold 1 (60%). If the SOC of the energy storage battery in the energy storage system is not greater than Threshold 1 (60%), the energy storage system does not execute the grid - connection strategy and enters the standby mode to wait for charging. If the SOC of the energy storage battery in the energy storage system is greater than Threshold 1 (60%), the energy storage system enters the economic mode, executes Grid - connection Strategy 1, and the energy storage battery performs charge - discharge operations independently.

[0042] 2.2 When the energy storage system is waiting for charging, if a new - energy vehicle accesses the emergency power supply system, the accessed new - energy vehicle is connected to the grid through the V2G interaction module. At this time, the vehicle system enters the economic mode, executes Grid - connection Strategy 2, and the new - energy vehicle battery performs charge - discharge operations independently.

[0043] 2.3 When the energy storage system executes Grid - connection Strategy 1, if a new - energy vehicle accesses the emergency power supply system, the accessed new - energy vehicle is connected to the grid through the V2G interaction module. At this time, the vehicle system enters the economic mode, forming a vehicle - energy storage grid - connected system with the synergistic effect of the vehicle system and the energy storage system. The vehicle - energy storage grid - connected system executes Grid - connection Strategy 3, and the energy storage battery and the new - energy vehicle battery perform charge - discharge operations synergistically.

[0044] Among them, the first threshold is usually set at 60%. The energy storage system needs to reserve emergency capacity to supply power to the load in case of grid anomalies. Therefore, when the emergency power supply system is in the grid-connected economic mode, when the SOC of the energy storage battery is not greater than 60%, the energy storage system does not participate in charge and discharge operations to ensure emergency situations; at this time, if a new energy vehicle is connected, the vehicle system executes the second grid-connected strategy to perform charge and discharge operations. When the SOC of the energy storage battery is greater than 60%, the energy storage system executes the first grid-connected strategy to perform charge and discharge operations; and when a new energy vehicle is connected, a vehicle-storage grid-connected system is formed to execute the third grid-connected strategy, and the energy storage battery and the vehicle battery cooperate to perform charge and discharge operations.

[0045] Among them, the first grid-connected strategy, the second grid-connected strategy, and the third grid-connected strategy executed by the emergency power supply system in the grid-connected economic mode are all based on the peak-valley arbitrage strategy, and the system output power is adjusted according to the load power and the grid power during the peak and valley periods of the grid, aiming to obtain greater economic benefits.

[0046] When the energy storage system executes the first grid-connected strategy, the energy storage battery increases the output power when the grid electricity price is high to perform discharge compensation, and charges and stores energy when the grid electricity price is low. This process is an existing technology and will not be elaborated here.

[0047] When the vehicle system executes the second grid-connected strategy, the vehicle battery increases the output power when the grid electricity price is high to perform discharge compensation, and charges and stores energy when the grid electricity price is low.

[0048] When the vehicle-storage grid-connected system executes the third grid-connected strategy, the energy storage battery and the vehicle battery perform cooperative discharge compensation when the grid electricity price is high, and perform cooperative charge and storage when the grid electricity price is low.

[0049] The specific process is as follows: (1) Calculate the dischargeable time of the vehicle battery according to the agreed parameters and vehicle information . Among them, the agreed parameters are set by the user himself when connecting a new energy vehicle, and the agreed parameters include the discharge ratio coefficient , the planned exit time, and the planned exit capacity . The calculation formula for the dischargeable time is as follows:

[0050]

[0051] In the formula, is the available capacity of the vehicle battery, is the remaining capacity of the vehicle battery when the vehicle is connected, is the discharge ratio coefficient (0 < ≤ 1), is the current supplied power, is the average discharge power of the vehicle battery, is the efficiency (usually 90%).

[0052] (2) Dynamically calculate the discharge powers of the energy storage battery and the vehicle battery, and perform discharging collaboratively. Specifically, through the dynamic power distribution algorithm of the energy management system, comprehensively calculate the discharge power of the energy storage battery and the discharge power of the vehicle battery and perform distribution. The calculation formula is as follows:

[0053]

[0054] Among them, is the available capacity of the vehicle battery, is the total capacity of the energy storage battery, is the discharge ratio coefficient (0 < ≤ 1), is the real-time power on the grid side, is the real-time power on the load side, is the grid support coefficient (0 < ≤ 1, affected by the real-time grid resistance, generally taken as 0.9).

[0055] (3) After discharging is completed, calculate the charging power of the vehicle battery according to the agreed parameters and vehicle information , and the calculation process is as follows:

[0056]

[0057] In the formula, is the required compensation capacity, is the planned withdrawal capacity, is the currently supplied power, is the remaining connection time of the vehicle, the maximum charging power of the vehicle battery.

[0058] (4) When the vehicle access time reaches the planned withdrawal time, the vehicle withdraws and settles the economic benefits; (5) After the vehicle withdraws, the emergency power supply system continues to dynamically execute the corresponding grid connection strategy based on the monitored vehicle system information and energy storage system parameters.

[0059] It should be noted that: The new energy vehicle needs to complete the charge and discharge operations of the vehicle battery before the planned withdrawal time arrives, and ensure that the vehicle battery capacity reaches the planned withdrawal capacity when the vehicle withdraws , and rely on the charge and discharge operations of the vehicle battery to obtain the corresponding economic benefits during the discharge process.

[0060] Among them, the emergency power supply system determines whether a new energy vehicle is connected by detecting the gun insertion signal of the charging pile in real time. If the emergency power supply system detects the gun insertion signal, it means that a new energy vehicle is connected. Further, a handshake request is sent to the new energy vehicle through the V2G interaction module, and information interaction is carried out after the handshake is successful.

[0061] Step 3: When the emergency power supply system is in the off-grid emergency mode, it continuously judges the grid recovery situation. If the grid returns to the normal state, the emergency power supply system switches to the grid-connected economic operation mode and dynamically executes the corresponding grid-connected strategy; if the grid does not return to the normal state, the emergency power supply system remains in the off-grid emergency mode and dynamically executes the corresponding emergency strategy according to the energy storage system parameters and the vehicle system conditions.

[0062] The specific steps are as follows: 3.1 Judge whether the SOC of the energy storage battery in the energy storage system is less than Threshold 2 (20%). If the SOC of the energy storage battery in the energy storage system is less than Threshold 2 (20%), the diesel generator system enters the emergency mode, starts the diesel power generation module of the diesel generator system, and the diesel generator system executes Emergency Strategy 1 as the emergency power supply.

[0063] Specifically, after the diesel generator system starts, it supplies power to the load and uses the remaining power to supply power to the energy storage battery of the energy storage system. This process realizes the coordinated interaction of the diesel - energy storage - load system. In addition, during the power supply process of the diesel generator, if a vehicle is connected, the diesel generator system will also supply power to the vehicle, thus realizing the coordinated interaction of the diesel - energy storage - vehicle - load system. It should be noted that when the diesel generator system executes Emergency Strategy 1, if the SOC of the energy storage battery exceeds Threshold 1 (60%) and reaches the emergency capacity requirement, the diesel generator power supply is immediately terminated.

[0064] Among them, Threshold 2 is usually set to 20% to ensure the safe power of the energy storage battery and avoid damage to the energy storage battery due to too low power.

[0065] 3.2 If the SOC of the energy storage battery in the energy storage system is not less than Threshold 2 (20%), or the diesel generator system exits the power supply, the energy storage system enters the emergency mode, and the energy storage system executes Emergency Strategy 2 as the emergency power supply, enabling the energy storage battery to supply power to the load and realizing the coordinated interaction of the energy storage - load system.

[0066] 3.3 During the process of the energy storage system executing Emergency Strategy 2 as an emergency power source, it is determined whether a new energy vehicle is connected. If no new energy vehicle is connected, it is determined whether the state of charge (SOC) of the energy storage battery in the energy storage system requires starting the diesel generator system; if a new energy vehicle is connected, the vehicle system is put into the emergency mode to form a vehicle-storage emergency power source, and Emergency Strategy 3 is executed, enabling the energy storage battery and the vehicle battery to cooperate to supply power to the load, realizing the coordinated interaction of the vehicle-storage-load system. Among them, based on the principle of maximizing vehicle utilization, the vehicle battery is used as the main power supply, and the energy storage battery is used as the auxiliary power supply to supplement the remaining load demand.

[0067] The specific process is as follows: (1) Calculate the remaining connection time of the vehicle according to the agreed parameters and vehicle information and the available capacity of the vehicle battery . The calculation formulas are as follows:

[0068] In the formula, is the remaining capacity of the vehicle battery when the vehicle is connected, is the discharge ratio coefficient (0 < ≤1).

[0069] (2) Dynamically calculate the emergency discharge power of the vehicle battery , and discharge based on the emergency discharge power . The calculation formula is as follows:

[0070] In the formula, is the remaining connection time of the vehicle, is the available capacity of the vehicle battery, is the maximum discharge power of the vehicle battery.

[0071] (3) After the vehicle battery finishes discharging, it enters the standby state, and the energy storage battery performs the discharge operation to support the load operation.

[0072] When the vehicle connection time has not reached the planned exit time and the vehicle battery is in the standby state, if the power grid returns to the normal state, it is charged through the power grid to make its battery capacity reach the planned exit capacity ; if the diesel generator system is started, it is charged through the diesel generator system to make its battery capacity reach the planned exit capacity ; Among them, the calculation process of the charging power is as follows:

[0073]

[0074] In the formula, is the required compensation capacity, is the planned withdrawal capacity, is the currently supplied power, is the remaining connection time of the vehicle, is the maximum charging power of the vehicle battery.

[0075] (4) When the vehicle access time reaches the planned withdrawal time, the vehicle withdraws and settles the economic benefits.

[0076] (5) After the vehicle withdraws, the emergency power supply system continues to dynamically execute corresponding emergency strategies according to the energy storage system parameters and the vehicle system conditions.

[0077] It should be noted that when the emergency power supply system is in the off-grid emergency mode, if the grid state returns to normal, it will immediately switch to the grid-connected economic mode and dynamically execute corresponding grid-connected strategies according to the vehicle system information and the energy storage system parameters.

[0078] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A diesel-storage hybrid emergency power supply system based on V2G, characterized in that: It includes vehicle system, energy storage system and diesel generator system. The emergency power supply system includes grid-connected economic mode and off-grid emergency mode. When the grid is in normal condition, the emergency power supply system operates in the grid-connected economic mode, and executes corresponding grid-connected strategies according to the conditions of the vehicle system and energy storage system. On the basis of ensuring that the energy storage system has emergency capacity, the vehicle system and energy storage system are used to earn economic benefits. When the grid is in abnormal condition, the emergency power supply system operates in the off-grid emergency mode, and executes corresponding emergency strategies according to the conditions of the vehicle system and energy storage system. On the basis of ensuring the power supply to the load, the frequency of use of the diesel generator system is reduced.

2. The V2G-based diesel-storage hybrid emergency power supply system according to claim 1 is characterized in that: It also includes an energy management system for real-time collection of grid status, energy storage system status, vehicle system information, and load power requirements; based on the collected information, the energy management system controls the charging and discharging timing and power of the energy storage system, coordinates the charging and discharging process of new energy vehicles based on the V2G interaction module, and manages the start and stop of the diesel engine system and power distribution.

3. The V2G-based diesel-storage hybrid emergency power supply system according to claim 2 is characterized in that: The vehicle system includes a V2G interaction module and an external new energy vehicle, and the energy management system realizes information interaction with the new energy vehicle through the V2G interaction module; The vehicle system includes an economic mode and an emergency mode. When the vehicle system is in the economic mode, the new energy vehicle is connected to the power grid to earn economic benefits through the charging and discharging of the vehicle battery; when the vehicle system is in the emergency mode, the new energy vehicle is connected to the load to support the normal operation of the load through the discharge of the vehicle battery.

4. The V2G-based diesel-storage hybrid emergency power supply system according to claim 1 is characterized in that: The energy storage system includes an energy storage battery module and an energy storage converter module, wherein the energy storage converter module is used to realize AC / DC conversion between the energy storage battery and the power grid or between the energy storage battery and the load; The energy storage system includes an economic mode, an emergency mode and a standby mode. When the energy storage system is in the economic mode, the energy storage system is connected to the power grid and earns economic benefits through the charging and discharging of the energy storage battery; when the energy storage system is in the emergency mode, the energy storage system is connected to the load and supports the normal operation of the load through the discharge of the energy storage battery; when the energy storage system is in the standby mode, the energy storage system is connected to the power grid and waits for charging.

5. The V2G-based diesel-storage hybrid emergency power supply system according to claim 1 is characterized in that: The diesel generator system includes a diesel generator module, and the diesel generator system includes an emergency mode and a standby mode. Under normal circumstances, the diesel generator system is in the standby mode. When the power grid is abnormal and the energy storage system meets the diesel generator power supply conditions, the diesel generator system enters the emergency mode and serves as an emergency power supply to supply power to the load, energy storage battery, and vehicle battery.

6. The V2G-based diesel-storage hybrid emergency power supply system according to claim 1 is characterized in that: A power grid interaction module is configured between the load and the power grid. The power grid interaction module includes a static transfer switch STS. The static transfer switch STS is used to switch the load power supply. When the power grid is abnormal, the load power supply is switched to the emergency power supply system.

7. A control method for a diesel-storage hybrid emergency power supply system based on V2G, the emergency power supply system comprising a vehicle system, an energy storage system, a diesel-generating system and an energy management system, characterized in that: The control method comprises the following steps: Step 1: monitor the state of the power grid in real time and switch the corresponding operation mode according to the state of the power grid; the operation mode of the emergency power supply system includes a grid-connected economic mode and an off-grid emergency mode; Step 2: When the emergency power supply system is in the grid-connected economic mode, the corresponding grid-connected strategy is dynamically executed according to the vehicle system information and energy storage system parameters: When the energy storage system meets the grid connection conditions, the energy storage system enters the economic mode and executes the grid connection strategy 1, so that the energy storage battery can be charged and discharged independently; when the energy storage system does not meet the grid connection conditions, the energy storage system enters the standby mode and waits for charging; When the energy storage system is in standby mode, if a new energy vehicle is connected, the vehicle system enters the economic mode and executes the grid connection strategy 2, so that the battery of the new energy vehicle can be charged and discharged separately; When the energy storage system is in economic mode, if a new energy vehicle is connected, the vehicle system will enter economic mode, forming a vehicle-storage grid-connected system in which the vehicle system and the energy storage system work together, and the grid-connected strategy three will be implemented, so that the energy storage battery and the vehicle battery can be charged and discharged in coordination; Step 3: When the emergency power supply system is in off-grid emergency mode, the corresponding emergency strategy is dynamically executed according to the energy storage system parameters and vehicle system conditions: When the energy storage system meets the diesel generator power supply conditions, the diesel generator system is triggered to enter the emergency mode and execute emergency strategy 1 as an emergency power supply, so that the diesel generator system can supply power to the load, energy storage battery and vehicle battery; If the energy storage system does not meet the diesel power supply conditions, the energy storage system enters the emergency mode and executes emergency strategy 2 as an emergency power supply, so that the energy storage battery supplies power to the load, realizing the coordinated interaction of the storage-load system; When the energy storage system is in emergency mode, if a new energy vehicle is connected, the vehicle system will enter emergency mode, forming a vehicle-storage emergency power supply, and executing emergency strategy three, so that the energy storage battery and vehicle battery can work together to power the load, realizing the coordinated interaction of the vehicle-storage-load system.

8. The control method of the V2G-based diesel-storage hybrid emergency power supply system according to claim 7 is characterized in that: When the emergency power supply system forms a vehicle-storage grid-connected system to execute the grid-connected strategy three, the coordinated process of the energy storage battery and the vehicle battery for coordinated charging and discharging is as follows: Calculate the discharge time of the vehicle battery based on agreed parameters and vehicle information ; The agreed parameters include the discharge ratio coefficient , planned exit time, planned exit capacity ; Among them, the discharge time The calculation formula is as follows: In the formula, Provides capacity for vehicle batteries, The remaining capacity of the vehicle battery when the vehicle is connected. is the discharge proportional coefficient, is the current power supply, is the average discharge power of the vehicle battery, For efficiency; Dynamic calculation of energy storage battery discharge power , Vehicle battery discharge power , discharge in coordination, the calculation formula is as follows: in, Provides capacity for vehicle batteries, is the total capacity of the energy storage battery, is the discharge proportional coefficient, The real-time power of the grid side, is the real-time power on the load side, is the grid support factor; After the discharge is completed, the charging power of the vehicle battery is calculated based on the agreed parameters and vehicle information , the calculation process is as follows: In the formula, is the required compensation capacity, To plan the capacity withdrawal, is the current power supply, The remaining connection time of the vehicle. Maximum charging power of the vehicle battery; When the vehicle access time reaches the planned exit time, the vehicle exits and the economic benefits are settled; After the vehicle exits, the emergency power supply system continues to dynamically execute the corresponding grid connection strategy by monitoring the vehicle system information and energy storage system parameters.

9. The control method of the V2G-based diesel-storage hybrid emergency power supply system according to claim 7 is characterized in that: When the emergency power supply system forms a vehicle-storage emergency power supply and executes emergency strategy three, the energy storage battery and vehicle battery work together to power the load, realizing the coordinated interaction of the vehicle-storage-load system. Based on the principle of maximizing vehicle utilization, the vehicle battery is used as the main power supply and the energy storage battery as an auxiliary power supply. The compensable power of the vehicle battery is used first, and then the energy storage battery is used to supplement the remaining load demand.

10. The control method of the V2G-based diesel-storage hybrid emergency power supply system according to claim 9 is characterized in that: The emergency power supply system forms a vehicle-storage emergency power supply, executes emergency strategy three, enables the energy storage battery and the vehicle battery to collaboratively supply power to the load, and realizes the specific process of collaborative interaction of the vehicle-storage-load system as follows: Calculate the remaining vehicle connection time based on agreed parameters and vehicle information 、Vehicle battery available capacity , the calculation formula is as follows: In the formula, The remaining capacity of the vehicle battery when the vehicle is connected. is the discharge proportional coefficient; Dynamic calculation of vehicle battery emergency discharge power , and based on the emergency discharge power Discharge is performed, and the calculation formula is as follows: In the formula, The remaining connection time of the vehicle. Provides capacity for vehicle batteries, is the maximum discharge power of the vehicle battery; After the vehicle battery is discharged, it enters the standby state, and the energy storage battery performs the discharge operation to support the load operation; when the vehicle access time does not reach the planned exit time and the vehicle battery is in the standby state, if the power grid returns to normal, it will be charged through the power grid to make its battery capacity reach the planned exit capacity If the diesel engine system is started, the battery capacity will be charged to the planned exit capacity. ; Among them, the charging power The calculation process is as follows: In the formula, is the required compensation capacity, To plan the capacity withdrawal, is the current power supply, The remaining connection time of the vehicle. Maximum charging power of the vehicle battery; When the vehicle access time reaches the planned exit time, the vehicle exits and the economic benefits are settled; After the vehicle exits, the emergency power supply system continues to dynamically execute corresponding emergency strategies based on the energy storage system parameters and vehicle system conditions.

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