A power supply vehicle suitable for low-voltage area emergency power supply

Abstract

The application discloses a power supply vehicle suitable for emergency power supply of low-voltage transformer area, and belongs to the technical field of emergency power supply of power distribution networks. The power supply vehicle suitable for emergency power supply of low-voltage transformer area comprises a vehicle body, a bidirectional isolation type DC and DC module, a direct-current bus, a network construction type PCS, a STS synchronous switch, at least two direct-current fast charging interfaces, a central controller, a battery management system and a grid-connected interface. The vehicle body is a new energy mobile carrier with fast charging and fast discharging functions. The direct-current fast charging interface is arranged on the vehicle body, and the outer side end of the direct-current fast charging interface is electrically connected with the bidirectional isolation type DC and DC module, so that bidirectional electric energy interaction between a new energy automobile and the direct-current bus is realized. In addition, the direct-current fast charging interface adopts the national standard GB and T20234.3 standard. One end of the bidirectional isolation type DC and DC module is electrically connected with the direct-current fast charging interface, and the other end is electrically connected with the direct-current bus.

Description

Technical Field

[0001] This invention relates to the field of emergency power supply technology for power distribution networks, and more specifically, to a power supply vehicle suitable for emergency power supply in low-voltage distribution areas. Background Technology

[0002] As the final link in the distribution network, low-voltage distribution areas directly supply power to users, and their power supply reliability is closely related to users' production and daily life. In actual operation, low-voltage distribution areas often experience power outages due to natural disasters (such as typhoons, rainstorms, and earthquakes), equipment aging and failures, line maintenance, etc., requiring the rapid activation of emergency power supply measures to reduce power outage losses.

[0003] Traditional emergency power supply equipment mostly uses diesel generator vehicles, which rely on diesel combustion to generate electricity. This has several inherent drawbacks: First, the response speed is slow. Diesel generators require a preheating process to start, and it usually takes more than 30 minutes from arrival at the site to putting them into operation, making it difficult to meet the needs of scenarios such as precision equipment and medical loads that are sensitive to power outage time. Second, it has poor environmental performance. The combustion process produces a large amount of exhaust gas and noise pollution, making it unsuitable for areas with high environmental requirements, such as urban core areas and residential areas. Third, it has limited performance. It has low power density and a large size, and its mobility is insufficient, making it difficult to enter narrow transformer substations for operation. Fourth, it has poor adaptability and cannot cope with reverse power scenarios. When the total power generated by distributed photovoltaic, energy storage, and other power sources in the transformer substation exceeds the load demand, it will send reverse power to the diesel generator, leading to equipment damage or even safety accidents.

[0004] With the rapid development of the new energy vehicle industry, its on-board power batteries possess characteristics such as large-capacity energy storage, high-rate discharge, high safety, and long cycle life, providing new solutions for emergency power supply. However, in existing technologies, there are still many technical bottlenecks when directly connecting new energy vehicles as emergency power sources to low-voltage distribution areas: First, the access interfaces are not standardized; different brands and models of new energy vehicles have different fast-charging interface specifications, resulting in poor universality. Second, the operation process is complex, requiring additional adapter equipment and lacking professional battery status monitoring and control mechanisms, which can easily lead to overcharging and over-discharging risks. Third, the discharge power is insufficient; the external discharge power of new energy vehicle charging ports is usually less than 30kW, which is difficult to meet the comprehensive load power supply needs of low-voltage distribution areas. Fourth, there is no voltage and frequency regulation capability, making it impossible to achieve seamless grid connection and off-grid switching with low-voltage distribution areas. Short power outages are required when connecting or disconnecting from power supply, affecting the continuity of power supply. Fifth, it cannot be adapted to scenarios with high penetration rates of distributed power sources, and cannot absorb excess photovoltaic output in distribution areas, leading to energy waste.

[0005] Therefore, developing a low-voltage distribution area emergency power supply vehicle that is versatile, green and efficient, has seamless switching capabilities, and is adaptable to reverse power scenarios has become an urgent need in the field of power distribution network operation and maintenance. Summary of the Invention

[0006] To address the problems existing in the prior art, the purpose of this invention is to provide a power supply vehicle suitable for emergency power supply in low-voltage distribution areas. Addressing the issues of high pollution, slow response, and poor adaptability of traditional diesel emergency power supply vehicles, as well as the lack of standardized interfaces and seamless grid connection / off-grid capability in direct emergency power supply from new energy vehicles, this invention provides a power supply vehicle suitable for emergency power supply in low-voltage distribution areas. This vehicle achieves rapid response, green efficiency, and seamless switching for emergency power supply in low-voltage distribution areas, while also being compatible with scenarios involving the absorption of excess distributed photovoltaic power, thereby improving the emergency operation and maintenance level of the distribution network.

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] A power supply vehicle suitable for emergency power supply in low-voltage distribution areas includes a vehicle body, a bidirectional isolated DC and DC module, a DC bus, a grid-type PCS, an STS synchronous switch, at least two DC fast charging interfaces, a central controller, a battery management system, and a grid connection interface; the vehicle body is a new energy mobile carrier with fast charging and discharging functions. The DC fast charging interface is installed on the vehicle body, and its outer end is electrically connected to the bidirectional isolated DC and DC module to realize bidirectional power interaction between the new energy vehicle and the DC bus. The DC fast charging interface adopts the national standard GB and T20234.3. One end of the bidirectional isolated DC and DC module is electrically connected to the DC fast charging interface, and the other end is electrically connected to the DC bus. The vehicle's own power battery serves as an emergency energy storage unit, and is connected to the DC bus via a bidirectional isolated DC and DC module; the battery management system is connected to the vehicle's own power battery management system to monitor and manage the operating status of the vehicle's own power battery. The central controller is communicatively connected to the grid-type PCS, bidirectional isolated DC and DC modules, STS synchronous switch and battery management system, respectively, to receive the operating status signals of each component and issue corresponding control commands; the grid-type PCS is connected in parallel to the DC bus to invert the electrical energy on the DC bus into AC power that meets the power supply standards of the low-voltage distribution area, or to rectify the AC power into DC power to replenish the DC bus and the connected new energy vehicles, while providing stable voltage and frequency support for the low-voltage distribution area to ensure power supply, and has the ability to switch between independent operation and grid-connected operation modes. The grid connection interface is fixedly installed on the vehicle body. The grid-type PCS is electrically connected to the grid connection interface through a line with a circuit breaker. The grid connection interface is used to realize the physical connection between the grid-type PCS and the main power grid. The STS synchronous switch is connected in series between the output terminal of the grid-type PCS and the low-voltage distribution area power supply line. The STS synchronous switch, together with the line with the circuit breaker and the grid connection interface, realizes millisecond-level seamless switching of the protection distribution area between the power supply vehicle and the main power grid based on voltage phase and frequency synchronization detection. The at least two DC fast charging interfaces can simultaneously connect to at least two new energy vehicles, including pure electric vehicles and range-extended new energy vehicles, and the power supply vehicle itself can participate in power interaction as one of the new energy vehicles. The grid-type PCS has a bidirectional power flow function, which can switch between inverter mode and rectification mode. In inverter mode, it supplies power to the low-voltage distribution area, and in rectification mode, it charges the DC bus and connected new energy vehicles.

[0009] As a further technical solution of the present invention, the DC fast charging interface adopts the national standard GB and T20234.3 standard interface, and the DC charging power supported by a single channel is not less than 60kW. It also has reverse connection protection, overcurrent protection and overvoltage protection functions to ensure that the power output of the DC fast charging interface meets the standard. The reverse connection protection, overcurrent protection and overvoltage protection functions can effectively avoid damage to the interface and the new energy vehicle battery, and ensure the safety and stability of the fast charging process.

[0010] As a further technical solution of the present invention, the bidirectional isolated DC and DC module is a bidirectional DC and DC converter with voltage boosting and regulating function and electrical isolation capability. The isolation voltage is not less than 1kV and the conversion efficiency is not less than 95%, ensuring electrical safety and voltage matching between the new energy vehicle and the DC bus. The performance parameters of the bidirectional isolated DC and DC module are clearly defined to realize voltage boosting and regulating function and electrical isolation, improve power conversion efficiency, and ensure safe and compatible power interaction between the new energy vehicle and the DC bus.

[0011] As a further technical solution of the present invention, the grid-type PCS adopts a multi-level topology structure, supporting independent operation mode and grid-connected operation mode. In the independent operation mode, it can independently establish voltage and frequency references, providing black start capability for low-voltage distribution areas, with voltage regulation accuracy not exceeding ±2% and frequency regulation accuracy not exceeding ±0.5Hz. In the grid-connected operation mode, it can operate synchronously with the large power grid to achieve smooth power interaction. The multi-level topology structure improves the operational stability of the grid-type PCS, and the dual-mode switching can meet the black start and grid-connected power supply needs of distribution areas, accurately adjust voltage and frequency, and achieve smooth power interaction.

[0012] As a further technical solution of the present invention, the STS synchronous switch is a static switching switch with a switching time of less than 10ms. It has voltage phase detection and synchronization judgment functions, and can realize uninterrupted load switching between power supply vehicle and main grid power supply. The voltage fluctuation during the switching process does not exceed 5%. The fast switching capability of the static switching switch realizes uninterrupted power supply switching, reduces voltage fluctuation during the switching process, avoids damage to the transformer area load due to power supply switching, and ensures power supply continuity.

[0013] As a further technical solution of the present invention, the battery management system is communicatively connected to each DC fast charging interface, bidirectional isolated DC and DC modules, and grid-type PCS. It is used to monitor the battery SOC, single cell voltage, total voltage, discharge current, and temperature parameters of the connected new energy vehicle in real time. Based on the monitoring data, it coordinates the power output of the bidirectional isolated DC and DC modules and the working mode switching of the grid-type PCS. When the battery parameters exceed the safety threshold, it triggers shutdown protection. In the power consumption and protection mode, it dynamically allocates charging power based on the SOC value, giving priority to charging new energy vehicles with low battery levels. It optimizes the control logic of the battery management system, monitors the battery status in real time and coordinates the regulation of each component, triggers shutdown protection to avoid safety risks, and rationally allocates power to improve the rationality of energy utilization.

[0014] As a further technical solution of the present invention, a communication module is also included. The communication module supports 4G and 5G, Ethernet, RS485 communication protocols and IEC61850 standard protocol. It can achieve triple communication interaction with the power grid dispatching system, the new energy vehicle BMS system, and the low-voltage distribution area monitoring terminal. It can upload emergency power supply status, battery parameters, distribution area load and distributed power output data, receive dispatching instructions and feed back execution results, and provide data support for working mode switching. At the same time, it has data encryption and breakpoint resume functions to ensure transmission security and stability. The communication module supports multi-protocol interaction to realize data transmission with multiple devices. The encryption and breakpoint resume functions ensure data security and stability, and provide reliable support for working mode switching and power grid dispatching.

[0015] As a further technical solution of the present invention, two working modes are supported, and the two modes are intelligently switched through the coordinated control of the grid-type PCS bidirectional power flow and communication module and the battery management system: Positive energy consumption mode: When the low-voltage distribution area loses power due to natural disasters or equipment failures, the connected new energy vehicles discharge to the DC bus through the DC fast charging interface. The isolated DC and DC modules adjust the voltage to the rated value of the DC bus and achieve electrical isolation. The grid-type PCS switches to inverter mode to invert the DC power into AC power that meets the distribution area standards. The AC power is then connected to the low-voltage distribution area through the STS synchronous switch to provide emergency power supply for the load. The battery management system dynamically allocates the discharge power of each vehicle to match the load demand of the distribution area. Power Consumption and Protection Mode: When a power outage occurs in a distribution area with high penetration of renewable energy and a black start is required, the grid-type PCS switches to independent operation mode, autonomously establishing voltage and frequency references to provide black start support for the distribution area and assist in the recovery of the microgrid. When the output of distributed power sources such as photovoltaics in the distribution area exceeds the load demand, the grid-type PCS switches to rectification mode, rectifying the excess AC power in the distribution area into DC power. Through isolated DC and DC modules and DC fast charging interfaces, it charges new energy vehicles, absorbing the excess output of distributed power sources and maintaining the stability of the microgrid in the distribution area. The two working modes are intelligently switched, which not only meets the emergency power supply needs of low-voltage distribution areas, but also absorbs the excess output of distributed power sources, assists in the recovery of the microgrid in the distribution area, and improves the flexibility and stability of power supply.

[0016] As a further technical solution of the present invention, in the power consumption and protection mode, the battery management system allocates charging power based on the SOC value of the new energy vehicle, giving priority to charging new energy vehicles with an SOC of less than 30%, ensuring charging safety and reasonable energy allocation, optimizing the charging power allocation in the power consumption and protection mode, giving priority to charging new energy vehicles with low battery levels, taking into account both charging safety and reasonable energy allocation, and further improving energy utilization.

[0017] Compared with the prior art, the advantages of this invention are: This invention is green, efficient, and fast-responding: it abandons the traditional diesel generator and relies on the power battery of new energy vehicles for power supply, with no exhaust gas or noise pollution, meeting environmental protection requirements; new energy vehicles do not require preheating when starting and discharging, and it only takes 5 minutes from connection to power supply, which is more than 80% faster than the response speed of traditional power vehicles, and can quickly restore power supply to low-voltage distribution areas. High versatility and flexible power supply capacity: It adopts the national standard GB / T 20234.3 fast charging interface, which is compatible with mainstream pure electric and range-extended new energy vehicles; it is equipped with at least two interfaces, which can connect multiple new energy vehicles at the same time. The power supply capacity can be expanded as needed to meet the needs of low-voltage distribution areas with different load scales. At the same time, the power vehicle itself can be used as an energy storage unit to improve emergency redundancy. Seamless switching and continuous power supply: Through the coordinated operation of the grid-type PCS and STS synchronous switch, millisecond-level seamless switching between the power supply vehicle and the main power grid is achieved. The switching time is less than 10ms, and the voltage fluctuation is small. It can realize zero-power-outage maintenance or emergency power supply switching in low-voltage distribution areas, meeting the needs of scenarios with high requirements for power supply continuity, such as medical and precision manufacturing. Dual-mode adaptation and high energy utilization: It supports both forward emergency power supply and photovoltaic excess output absorption modes, which not only solves the problem of power outage emergency in low-voltage distribution areas, but also adapts to the black start and energy absorption needs of distribution areas with high penetration of new energy, avoids waste of distributed photovoltaic excess output, and improves the new energy absorption capacity of the distribution network. Safe, reliable, intelligent and controllable: Equipped with an isolated DC / DC module to achieve electrical isolation, the battery management system monitors the battery status in real time and triggers multi-level protection, and the STS synchronous switch has a phase synchronization detection function, providing multiple guarantees for power supply safety; remote monitoring and intelligent scheduling are achieved through the communication module, adapting to the digital operation and maintenance needs of the power distribution network. Attached Figure Description

[0018] Figure 1 This is a topological diagram of the power supply vehicle structure of the present invention; Figure 2 This is a flowchart illustrating the working mode switching process of the present invention. Figure 3 This is a schematic diagram of the power supply topology for the positive energy consumption mode of the present invention; Figure 4 This is a topological diagram of the energy flow direction in the power absorption and retention mode of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention provides an embodiment 1 Please see Figure 1-4 A power supply vehicle suitable for emergency power supply in low-voltage distribution areas includes a vehicle body, a bidirectional isolated DC and DC module, a DC bus, a grid-type PCS, an STS synchronous switch, at least two DC fast charging interfaces, a central controller, a battery management system, and a grid connection interface; the vehicle body is a new energy mobile carrier with fast charging and discharging functions. The DC fast charging interface is installed on the vehicle body, and its outer end is electrically connected to the bidirectional isolated DC and DC module to realize bidirectional power interaction between the new energy vehicle and the DC bus. The DC fast charging interface adopts the national standard GB and T20234.3. One end of the bidirectional isolated DC and DC module is electrically connected to the DC fast charging interface, and the other end is electrically connected to the DC bus. The vehicle's own power battery serves as an emergency energy storage unit, and is connected to the DC bus via a bidirectional isolated DC and DC module; the battery management system is connected to the vehicle's own power battery management system to monitor and manage the operating status of the vehicle's own power battery. The central controller is communicatively connected to the grid-type PCS, bidirectional isolated DC and DC modules, STS synchronous switch and battery management system, respectively, to receive the operating status signals of each component and issue corresponding control commands; the grid-type PCS is connected in parallel to the DC bus to invert the electrical energy on the DC bus into AC power that meets the power supply standards of the low-voltage distribution area, or to rectify the AC power into DC power to replenish the DC bus and the connected new energy vehicles, while providing stable voltage and frequency support for the low-voltage distribution area to ensure power supply, and has the ability to switch between independent operation and grid-connected operation modes. The grid connection interface is fixedly installed on the vehicle body. The grid-type PCS is electrically connected to the grid connection interface through a line with a circuit breaker. The grid connection interface is used to realize the physical connection between the grid-type PCS and the main power grid. The STS synchronous switch is connected in series between the output terminal of the grid-type PCS and the low-voltage distribution area power supply line. The STS synchronous switch, together with the line with the circuit breaker and the grid connection interface, realizes millisecond-level seamless switching of the protection distribution area between the power supply vehicle and the main power grid based on voltage phase and frequency synchronization detection. The at least two DC fast charging interfaces can simultaneously connect to at least two new energy vehicles, including pure electric vehicles and range-extended new energy vehicles, and the power supply vehicle itself can participate in power interaction as one of the new energy vehicles. The grid-type PCS has a bidirectional power flow function, which can switch between inverter mode and rectification mode. In inverter mode, it supplies power to the low-voltage distribution area, and in rectification mode, it charges the DC bus and the connected new energy vehicles. The DC fast charging interface adopts the national standard GB and T20234.3 standard interface, and the DC charging power supported by a single channel is not less than 60kW. It also has reverse connection protection, overcurrent protection and overvoltage protection functions to ensure that the power output of the DC fast charging interface meets the standard. The reverse connection protection, overcurrent protection and overvoltage protection functions can effectively prevent damage to the interface and the new energy vehicle battery, and ensure the safety and stability of the fast charging process. The bidirectional isolated DC and DC modules are bidirectional DC and DC converters with voltage boost and pull regulation functions and electrical isolation capabilities. The isolation voltage is not less than 1kV and the conversion efficiency is not less than 95%. They ensure electrical safety and voltage matching between new energy vehicles and DC buses. The performance parameters of the bidirectional isolated DC and DC modules are clearly defined to realize voltage boost and pull regulation and electrical isolation, improve power conversion efficiency, and ensure safe and compatible power interaction between new energy vehicles and DC buses. The grid-connected PCS adopts a multi-level topology and supports both stand-alone and grid-connected operation modes. In stand-alone operation mode, it can autonomously establish voltage and frequency references, providing black-start capability for low-voltage distribution areas, with voltage regulation accuracy not exceeding ±2% and frequency regulation accuracy not exceeding ±0.5Hz. In grid-connected operation mode, it can operate synchronously with the main power grid to achieve smooth power interaction. The multi-level topology enhances the operational stability of the grid-connected PCS, and the dual-mode switching can meet the black-start and grid-connected power supply needs of distribution areas, accurately adjusting voltage and frequency to achieve smooth power interaction. The STS synchronous switch is a static switching switch with a switching time of less than 10ms. It has voltage phase detection and synchronization judgment functions, and can realize uninterrupted load switching between power supply vehicle and main grid power supply. The voltage fluctuation during the switching process does not exceed 5%. The fast switching capability of the static switching switch realizes uninterrupted power supply switching, reduces voltage fluctuation during the switching process, avoids damage to the transformer area load due to power supply switching, and ensures power supply continuity. The battery management system is connected to each DC fast charging interface, bidirectional isolated DC and DC modules, and grid-type PCS. It is used to monitor the battery SOC, single cell voltage, total voltage, discharge current, and temperature parameters of the connected new energy vehicles in real time. Based on the monitoring data, it coordinates the power output of the bidirectional isolated DC and DC modules and the working mode switching of the grid-type PCS. When the battery parameters exceed the safety threshold, it triggers shutdown protection. In the power consumption and protection mode, it dynamically allocates charging power based on the SOC value, giving priority to charging new energy vehicles with low battery levels. It optimizes the control logic of the battery management system, monitors the battery status in real time and coordinates the regulation of various components, triggers shutdown protection to avoid safety risks, and rationally allocates power to improve the rationality of energy utilization. It also includes a communication module that supports 4G and 5G, Ethernet, RS485 communication protocols and IEC61850 standard protocol. It can achieve triple communication interaction with the power grid dispatching system, the new energy vehicle BMS system and the low-voltage distribution area monitoring terminal. It can upload emergency power supply status, battery parameters, distribution area load and distributed power output data, receive dispatching instructions and feed back execution results, and provide data support for working mode switching. It also has data encryption and breakpoint resume functions to ensure transmission security and stability. The communication module supports multi-protocol interaction to realize data transmission with multiple devices. The encryption and breakpoint resume functions ensure data security and stability, and provide reliable support for working mode switching and power grid dispatching. It supports two operating modes, and the two modes are intelligently switched through the coordinated control of the network-type PCS bidirectional power flow and communication module and the battery management system: Positive energy consumption mode: When the low-voltage distribution area loses power due to natural disasters or equipment failures, the connected new energy vehicles discharge to the DC bus through the DC fast charging interface. The isolated DC and DC modules adjust the voltage to the rated value of the DC bus and achieve electrical isolation. The grid-type PCS switches to inverter mode to invert the DC power into AC power that meets the distribution area standards. The AC power is then connected to the low-voltage distribution area through the STS synchronous switch to provide emergency power supply for the load. The battery management system dynamically allocates the discharge power of each vehicle to match the load demand of the distribution area. Power Supply Consumption and Protection Mode: When a power outage occurs in a distribution area with high penetration of renewable energy and a black start is required, the grid-type PCS switches to independent operation mode, autonomously establishing voltage and frequency references to provide black start support for the distribution area and assist in the recovery of the microgrid. When the output of distributed power sources such as photovoltaics in the distribution area exceeds the load demand, the grid-type PCS switches to rectification mode, rectifying the excess AC power in the distribution area into DC power. Through isolated DC and DC modules and DC fast charging interfaces, it charges new energy vehicles, absorbing the excess output of distributed power sources and maintaining the stability of the microgrid in the distribution area. The two working modes are intelligently switched, which not only meets the emergency power supply needs of low-voltage distribution areas, but also absorbs the excess output of distributed power sources, assists in the recovery of the microgrid in the distribution area, and improves the flexibility and stability of power supply. Under the power supply and consumption mode, the battery management system allocates charging power based on the SOC value of the new energy vehicle, giving priority to charging new energy vehicles with an SOC of less than 30%, ensuring charging safety and reasonable energy allocation. It optimizes the charging power allocation under the power supply and consumption mode, giving priority to charging new energy vehicles with low battery levels, taking into account both charging safety and reasonable energy allocation, and further improving energy utilization. This invention provides an embodiment 2 A power supply vehicle suitable for emergency power supply in low-voltage distribution areas, with the following specific configuration: The vehicle body uses a certain brand of range-extended light truck, equipped with a 100kWh power battery, supports fast charging and discharging, and the fast charging power can reach 80kW. The vehicle body size is suitable for passing through narrow roads in rural and urban areas. The equipment compartment has a built-in forced air cooling system, and the working environment temperature range is -20℃~55℃. The DC fast charging interface is configured with two channels, both of which adopt the national standard GB / T 20234.3. The maximum discharge power of a single channel is 80kW, the interface protection level is IP54, and it has reverse connection protection, overcurrent (maximum 150A) and overvoltage (maximum 1000V) protection functions. It is installed at the rear of the vehicle body and equipped with an openable dust cover. The isolated DC / DC module adopts a bidirectional full-bridge topology, with an input voltage range of 200V~800V, an output voltage stable at 750V (DC bus rated voltage), an isolation voltage of 1.5kV, a conversion efficiency of 96.5%, a rated power of 160kW, and supports parallel expansion. It is connected one-to-one with the DC fast charging interface. The grid-connected PCS adopts a three-level NPC topology, with a rated power of 200kW, an input voltage of 750V, an output voltage of 380V / 3P4W, and a frequency of 50Hz. In independent operation mode, the voltage regulation accuracy is ±1.5%, the frequency regulation accuracy is ±0.3Hz, and the black start capability supports driving a 100kW inductive load. In grid-connected operation mode, the power factor regulation range is 0.8 (leading) to 0.8 (lagging), and it has frequency and voltage support functions. The STS synchronous switch is a static switching switch with a rated current of 400A, a rated voltage of 400V, a switching time of 8ms, a built-in phase detection unit, a synchronization error allowable range of ±3°, manual / automatic switching modes, and supports fault self-diagnosis. The battery management system uses a multi-core processor with a sampling frequency of 10Hz. It can monitor the battery parameters of two new energy vehicles simultaneously, with a SOC estimation accuracy of ±2%. It supports CAN / LIN bus communication and can exchange data with the networked PCS and communication module in real time. The communication module integrates a 4G / 5G dual-mode module and an Ethernet interface, supports the IEC 61850 protocol, can be connected to the power grid dispatching system, has a data transmission rate of no less than 10Mbps, and has data encryption and breakpoint resume functions. This invention provides an application example Scenario 1: Power outage due to equipment failure in low-voltage distribution area (positive energy consumption mode) A power outage occurred in a residential low-voltage distribution area in a city due to a transformer failure. The total load capacity was 120kW, including some household appliances and small shop loads. After the power supply vehicle arrived at the scene, the operators connected the power supply vehicle (a range-extended light truck) and an external pure electric pickup truck to the power supply vehicle via a DC fast charging interface. The total battery capacity of the two vehicles was 220kWh, and the SOC of both vehicles was 80%.

[0021] In the positive energy consumption mode, the battery management system collects battery parameters from both vehicles. After confirming that the status is normal, it controls the isolated DC / DC module to start, adjusting the DC output from both vehicles to the 750V DC bus voltage. The grid-type PCS switches to independent operation mode, autonomously establishing a 380V / 50Hz voltage reference. It connects to the load side of the distribution area via the STS synchronous switch to quickly restore power supply. The power supply is allocated as follows: 60kW for the power supply vehicle and 60kW for the external pickup truck, matching the load demand of the distribution area.

[0022] After the power grid maintenance personnel completed the transformer overhaul, the main power grid resumed power supply. The STS synchronous switch detected that the grid voltage, frequency, and phase were consistent with the power supply vehicle's output, and a seamless switchover was completed within 8ms, allowing the load to smoothly transition to the main power grid. Subsequently, the grid-type PCS stopped inverterizing, the isolated DC / DC module cut off the discharge circuit, and the power supply vehicle withdrew from power supply. The entire process was completed without any power outages, and users' power consumption was unaffected.

[0023] Scenario 2: Black start-up and photovoltaic power consumption in areas with high penetration of new energy sources (power consumption guarantee mode) A rural low-voltage distribution area is equipped with 150kW photovoltaic modules and has a peak load of 100kW. Due to a typhoon, a power outage occurred, requiring the initiation of black start and absorption of excess photovoltaic output. After the power supply vehicle arrived at the scene, it connected itself with a pure electric truck (SOC 30%) and initiated the absorption and power supply mode.

[0024] The grid-connected PCS switches to independent operation mode, providing voltage and frequency support to the distribution area, initiating the black start process, and gradually waking up the photovoltaic inverters and energy storage devices in the distribution area to build a microgrid. After 1 hour, the photovoltaic output reaches 120kW, the distribution area load is 80kW, resulting in a 40kW excess output.

[0025] The battery management system detects excess photovoltaic output and sends a mode switching command to the grid-connected PCS. The grid-connected PCS switches to rectification mode, rectifying 40kW of the excess 120kW AC power in the distribution area into 750V DC power. After adjustment by an isolated DC / DC module, this DC power is used to charge an external pure electric truck at a charging power of 40kW. The remaining 80kW AC power supplies the distribution area load. The battery management system monitors the truck's SOC in real time. When the SOC rises to 80%, the charging power is adjusted to 20kW to prioritize load power supply, continuously absorbing excess photovoltaic output and improving energy utilization. In summary, this invention is green, efficient, and responsive: it abandons the traditional diesel generator and relies on the power battery of new energy vehicles for power supply, with no exhaust gas or noise pollution, meeting environmental protection requirements; new energy vehicles do not require preheating when starting and discharging, and it only takes 5 minutes from connection to power supply, which is more than 80% faster than traditional power vehicles, and can quickly restore power supply to low-voltage distribution areas. High versatility and flexible power supply capacity: It adopts the national standard GB / T 20234.3 fast charging interface, which is compatible with mainstream pure electric and range-extended new energy vehicles; it is equipped with at least two interfaces, which can connect multiple new energy vehicles at the same time. The power supply capacity can be expanded as needed to meet the needs of low-voltage distribution areas with different load scales. At the same time, the power vehicle itself can be used as an energy storage unit to improve emergency redundancy. Seamless switching and continuous power supply: Through the coordinated operation of the grid-type PCS and STS synchronous switch, millisecond-level seamless switching between the power supply vehicle and the main power grid is achieved. The switching time is less than 10ms, and the voltage fluctuation is small. It can realize zero-power-outage maintenance or emergency power supply switching in low-voltage distribution areas, meeting the needs of scenarios with high requirements for power supply continuity, such as medical and precision manufacturing. Dual-mode adaptation and high energy utilization: It supports both forward emergency power supply and photovoltaic excess output absorption modes, which not only solves the problem of power outage emergency in low-voltage distribution areas, but also adapts to the black start and energy absorption needs of distribution areas with high penetration of new energy, avoids waste of distributed photovoltaic excess output, and improves the new energy absorption capacity of the distribution network. Safe, reliable, intelligent and controllable: Equipped with an isolated DC / DC module to achieve electrical isolation, the battery management system monitors the battery status in real time and triggers multi-level protection, and the STS synchronous switch has a phase synchronization detection function, providing multiple guarantees for power supply safety; remote monitoring and intelligent scheduling are achieved through the communication module, adapting to the digital operation and maintenance needs of the power distribution network.

[0026] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A power supply vehicle suitable for emergency power supply in low-voltage distribution areas, characterized in that: It includes a vehicle body, a bidirectional isolated DC and DC module, a DC bus, a grid-type PCS, an STS synchronous switch, at least two DC fast charging interfaces, a central controller, a battery management system, and a grid connection interface; the vehicle body is a new energy mobile carrier with fast charging and discharging capabilities. The DC fast charging interface is installed on the vehicle body, and its outer end is electrically connected to the bidirectional isolated DC and DC module to realize bidirectional power interaction between the new energy vehicle and the DC bus. The DC fast charging interface adopts the national standard GB and T20234.

3. One end of the bidirectional isolated DC and DC module is electrically connected to the DC fast charging interface, and the other end is electrically connected to the DC bus. The vehicle's own power battery serves as an emergency energy storage unit, and is connected to the DC bus via a bidirectional isolated DC and DC module; the battery management system is connected to the vehicle's own power battery management system to monitor and manage the operating status of the vehicle's own power battery. The central controller is communicatively connected to the grid-type PCS, bidirectional isolated DC and DC modules, STS synchronous switch and battery management system, respectively, to receive the operating status signals of each component and issue corresponding control commands; the grid-type PCS is connected in parallel to the DC bus to invert the electrical energy on the DC bus into AC power that meets the power supply standards of the low-voltage distribution area, or to rectify the AC power into DC power to replenish the DC bus and the connected new energy vehicles, while providing stable voltage and frequency support for the low-voltage distribution area to ensure power supply, and has the ability to switch between independent operation and grid-connected operation modes. The grid connection interface is fixedly installed on the vehicle body. The grid-type PCS is electrically connected to the grid connection interface through a line with a circuit breaker. The grid connection interface is used to realize the physical connection between the grid-type PCS and the main power grid. The STS synchronous switch is connected in series between the output terminal of the grid-type PCS and the low-voltage distribution area power supply line. The STS synchronous switch, together with the line with the circuit breaker and the grid connection interface, realizes millisecond-level seamless switching of the protection distribution area between the power supply vehicle and the main power grid based on voltage phase and frequency synchronization detection. The at least two DC fast charging interfaces can simultaneously connect to at least two new energy vehicles, including pure electric vehicles and range-extended new energy vehicles, and the power supply vehicle itself can participate in power interaction as one of the new energy vehicles. The grid-type PCS has a bidirectional power flow function, which can switch between inverter mode and rectification mode. In inverter mode, it supplies power to the low-voltage distribution area, and in rectification mode, it charges the DC bus and connected new energy vehicles.

2. A power supply vehicle suitable for emergency power supply in low-voltage distribution areas according to claim 1, characterized in that: The DC fast charging interface adopts the national standard GB and T20234.3 standard interface, and the DC charging power supported by a single channel is not less than 60kW. It also has reverse connection protection, overcurrent protection, and overvoltage protection functions.

3. A power supply vehicle suitable for emergency power supply in low-voltage distribution areas according to claim 1, characterized in that: The bidirectional isolated DC and DC modules are bidirectional DC and DC converters with voltage boost / down regulation and electrical isolation capabilities. The isolation voltage is not less than 1kV and the conversion efficiency is not less than 95%, ensuring electrical safety and voltage matching between the new energy vehicle and the DC bus.

4. A power supply vehicle suitable for emergency power supply in low-voltage distribution areas according to claim 1, characterized in that: The grid-type PCS adopts a multi-level topology and supports both independent and grid-connected operation modes. In independent operation mode, it can independently establish voltage and frequency references, providing black start capability for low-voltage distribution areas, with voltage regulation accuracy not exceeding ±2% and frequency regulation accuracy not exceeding ±0.5Hz. In grid-connected operation mode, it can operate synchronously with the main power grid to achieve smooth power interaction.

5. A power supply vehicle suitable for emergency power supply in low-voltage distribution areas according to claim 1, characterized in that: The STS synchronous switch is a static switching switch with a switching time of less than 10ms. It has voltage phase detection and synchronization judgment functions, and can realize uninterrupted load switching between power supply vehicle and main grid power supply. The voltage fluctuation during the switching process does not exceed 5%.

6. A power supply vehicle suitable for emergency power supply in low-voltage distribution areas according to claim 1, characterized in that: The battery management system is connected to each DC fast charging interface, bidirectional isolated DC and DC modules, and grid-type PCS. It is used to monitor the battery SOC, single cell voltage, total voltage, discharge current, and temperature parameters of the connected new energy vehicles in real time. Based on the monitoring data, it coordinates the power output of the bidirectional isolated DC and DC modules and the working mode switching of the grid-type PCS. When the battery parameters exceed the safety threshold, it triggers the shutdown protection. In the power consumption and protection mode, it dynamically allocates charging power based on the SOC value, giving priority to charging new energy vehicles with low battery levels.

7. A power supply vehicle suitable for emergency power supply in low-voltage distribution areas according to claim 1, characterized in that: It also includes a communication module that supports 4G and 5G, Ethernet, RS485 communication protocols and IEC61850 standard protocol. It can achieve triple communication interaction with the power grid dispatching system, the new energy vehicle BMS system and the low-voltage distribution area monitoring terminal, upload emergency power supply status, battery parameters, distribution area load and distributed power output data, receive dispatching instructions and feed back execution results, provide data support for working mode switching, and has data encryption and breakpoint resume functions to ensure transmission security and stability.

8. A power supply vehicle suitable for emergency power supply in low-voltage distribution areas according to any one of claims 1-7, characterized in that: It supports two operating modes, and the two modes are intelligently switched through the coordinated control of the network-type PCS bidirectional power flow and communication module and the battery management system: Positive energy consumption mode: When the low-voltage distribution area loses power due to natural disasters or equipment failures, the connected new energy vehicles discharge to the DC bus through the DC fast charging interface. The isolated DC and DC modules adjust the voltage to the rated value of the DC bus and achieve electrical isolation. The grid-type PCS switches to inverter mode to invert the DC power into AC power that meets the distribution area standards. The AC power is then connected to the low-voltage distribution area through the STS synchronous switch to provide emergency power supply for the load. The battery management system dynamically allocates the discharge power of each vehicle to match the load demand of the distribution area. Power Consumption and Supply Mode: When a power outage occurs in a distribution area with high penetration of renewable energy and a black start is required, the grid-type PCS switches to independent operation mode, autonomously establishes voltage and frequency references, provides black start support for the distribution area, and helps the microgrid in the distribution area to recover; when the output of distributed power sources such as photovoltaics in the distribution area exceeds the load demand, the grid-type PCS switches to rectification mode, rectifies the excess AC power in the distribution area into DC power, and charges new energy vehicles through isolated DC and DC modules and DC fast charging interfaces, absorbing the excess output of distributed power sources and maintaining the stability of the microgrid in the distribution area.

9. A power supply vehicle suitable for emergency power supply in low-voltage distribution areas according to claim 8, characterized in that: In the power consumption and protection mode, the battery management system allocates charging power based on the SOC value of the new energy vehicle, giving priority to charging new energy vehicles with an SOC of less than 30%, ensuring charging safety and reasonable energy allocation.

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