Non-inductive conversion control method for network-forming type energy storage power station

Abstract

The invention discloses a non-inductive conversion control method for a network construction type energy storage power station. By monitoring the state of a main power supply in real time, once a fault occurs, non-inductive switching of an off-grid / grid-connected mode is realized within millisecond-level time by means of control logic based on a pre-synchronization control algorithm and a rapid power compensation algorithm, and continuous and uninterrupted power supply of a load is ensured; and smooth grid connection can be realized after power grid recovery. Besides, an energy management system (EMS) dynamically adjusts an operation strategy based on an objective function which takes the real-time operation cost, the energy storage state of charge (SOC) standard-reaching rate and the load power fluctuation coefficient of the network construction type energy storage power station as optimization objectives, so that the uninterruptible power supply requirement of the load can be met, and the power grid frequency and voltage stability can be actively supported. According to the method, the problems of slow response and single function of a traditional emergency power supply are solved, and millisecond-level non-inductive switching and stable power supply in a major scene are realized.

Description

Technical Field

[0001] This invention relates to the field of emergency power supply technology for power systems, and in particular to a sensorless switching control method for a grid-type energy storage power station. Background Technology

[0002] Some critical scenarios (such as major sporting events) have extremely high requirements for power supply reliability. Traditional emergency power supply solutions often use equipment such as diesel generators and UPS uninterruptible power supplies, which have problems such as slow response speed (seconds or more), need to be connected to the power grid through a transformer, can only passively supply power and cannot actively adjust the grid parameters, and have limited endurance.

[0003] As a cutting-edge direction in the field of power electronics control and new energy storage, grid-based energy storage technology has the ability to actively form a grid and support the power grid. However, there is currently no precedent for applying grid-based energy storage systems to emergency power supply and achieving millisecond-level seamless switching. Specifically, existing grid-based energy storage technologies lack a complete technical solution for seamless switching and rapid power restoration adapted to large-scale event scenarios, and cannot meet the core requirements such as millisecond-level power supply switching, long-term uninterrupted power supply, and active adjustment of grid parameters during events.

[0004] Therefore, there is an urgent need to develop a grid-based energy storage power station method for seamless switching and rapid power restoration in emergency power supply scenarios for large-scale events, in order to solve the problems of slow response, single function and poor adaptability of traditional power supply solutions, and achieve millisecond-level seamless switching and stable restoration of power supply in major event scenarios.

[0005] It should be noted that the information disclosed in the background section above is only for understanding the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The top-level technical problem that this invention aims to solve is: how to achieve seamless switching and continuous stable power supply in power supply systems for critical occasions; specifically, it can be manifested as: how to enable the grid-type energy storage converter to switch from grid-connected to off-grid mode within milliseconds through a fast and precise control method when the main power supply fails, and maintain the stability of power supply parameters during the switching process and in off-grid mode, so that the load has no power outage perception.

[0007] Therefore, this application provides a sensorless switching control method for a grid-type energy storage power station to solve the above-mentioned technical problems.

[0008] The technical solution adopted in this application to solve the above-mentioned technical problems is as follows.

[0009] The first aspect of this application provides a sensorless conversion control method for a grid-type energy storage power station, the grid-type energy storage power station including a grid-type energy storage converter (PCS), the method comprising the following steps: Monitor the electrical parameters of the main power supply, and determine whether the main power supply has failed based on the comparison results of the electrical parameters with preset thresholds; When a fault is detected in the main power supply, an off-grid switching command is generated; In response to the off-grid switching command, the grid-connected energy storage converter (PCS) switches from grid-connected operation mode to off-grid operation mode within milliseconds, so that the grid-connected energy storage power station can independently supply power to the load. During the switching process, a closed-loop control strategy for electrical parameters is adopted to keep the power supply parameters stable and ensure that the load does not experience any power outage. Monitor the recovery status of the main power supply. When the main power supply stabilizes, control the grid-connected energy storage converter (PCS) to switch from off-grid operation mode back to grid-connected operation mode.

[0010] In some embodiments, the closed-loop control strategy for electrical parameters includes a pre-synchronization control algorithm and a fast power compensation algorithm.

[0011] In some embodiments, the electrical parameters include voltage and frequency. Based on the comparison of the electrical parameters with preset thresholds, it is determined whether the main power supply has failed, using the following formula:

[0012] in, This is a fault identification indicator; 1 indicates a main power supply failure, and 0 indicates normal operation. This refers to the voltage tolerance threshold. This is the permissible frequency deviation threshold; and These are the real-time voltage and frequency of the main power supply, respectively; and These are the voltage threshold and the frequency threshold, respectively; when the fault flag calculated from multiple consecutive samples is 1, it is determined that the main power supply has failed.

[0013] In some embodiments, the pre-synchronization control algorithm achieves tracking control of the output voltage and frequency of the grid-type energy storage converter (PCS) using the following formula:

[0014]

[0015] in, , The voltage and frequency output by the grid-type energy storage converter PCS at time t; and These are the voltage threshold and the frequency threshold; This is the voltage proportionality coefficient. This is the frequency scaling factor; and These are the real-time voltage and frequency of the main power supply, respectively.

[0016] In some embodiments, the fast power compensation algorithm is implemented using the following formula:

[0017] in: Real-time load power of the load; Output power before the main power supply failure; This is the power compensation coefficient; This represents the real-time output power of the grid-type energy storage converter (PCS) at time t.

[0018] In some embodiments, after switching to off-grid operation mode, dynamic operation strategy adjustment is performed through the energy management system (EMS). The dynamic operation strategy adjustment is based on an objective function that optimizes the operation of the grid-connected energy storage power station by taking the real-time operating cost of the grid-connected energy storage power station, the state of charge (SOC) compliance rate of the energy storage, and the load power fluctuation coefficient as optimization objectives.

[0019] In some embodiments, the objective function for dynamically adjusting the execution strategy is:

[0020] in, The real-time operating cost of the energy storage system includes battery cycle loss costs and auxiliary control system energy consumption costs; The SOC (State of Charge) compliance rate for energy storage; This refers to the load power fluctuation coefficient. These are the weighting coefficients.

[0021] In some embodiments, an improved particle swarm optimization (PSO) algorithm is used to solve the objective function. The iterative update formula of the PSO algorithm is as follows:

[0022]

[0023] in, For particle velocity, For the particle position, As inertia weights, an adaptive adjustment strategy is adopted. , As a learning factor, A random number in the range [0, 1] This represents the optimal position in the history of an individual particle. This represents the best historical position for the entire population.

[0024] In some embodiments, switching from off-grid operation mode back to grid-connected operation mode includes the following steps: achieving phase synchronization using a smooth synchronization algorithm before completing the grid-connected switch to avoid power surges. The formula for the smooth synchronization algorithm is as follows:

[0025] in, , The phase angle between the output voltage of the grid-type energy storage converter PCS and the main power supply voltage; Phase compensation coefficient The second aspect of this application provides a grid-type energy storage power station for power supply guarantee, comprising: one or more prefabricated compartments; a grid-type energy storage converter (PCS) installed in the prefabricated compartment and configured to execute the sensorless conversion control method of the first aspect of this application; an energy storage battery electrically connected to the grid-type energy storage converter (PCS); an energy management system (EMS) communicatively connected to the grid-type energy storage converter (PCS) and configured to monitor the operating status of the energy storage power station and send control commands; and a fire protection system installed in the prefabricated compartment.

[0026] The present invention has the following beneficial effects: This application fundamentally solves the technical problem of traditional power supply systems' inability to achieve seamless switching and continuous stable power supply in critical situations through a closed-loop control process encompassing "monitoring, judgment, rapid switching, stable control, and recovery." This application ensures that in the event of a main power supply failure, the grid-connected energy storage converter (PCS) can seamlessly take over power supply within milliseconds. During the switching process and off-grid operation, the closed-loop control strategy maintains high stability of power supply parameters such as voltage and frequency, ultimately achieving the core benefit of completely eliminating power outage awareness for the load and meeting the extreme reliability requirements of critical scenarios.

[0027] Specifically, this application continuously monitors the electrical parameters of the main power supply and compares them with preset thresholds, which enables the rapid and accurate identification of power supply faults. This provides key triggering conditions and time guarantees for subsequent millisecond-level switching, avoiding false starts or failures to start, and ensuring the timeliness of switching from the source.

[0028] Specifically, this application generates and responds to an off-grid switching command immediately upon fault detection, controlling the grid-connected energy storage converter (PCS) to complete the transition from grid-connected to off-grid mode within milliseconds. This feature directly addresses the issue of "slow response," and its extremely short switching time is the core foundation for achieving "seamless" switching, completely eliminating power interruptions caused by switching delays.

[0029] Specifically, this application employs a closed-loop control strategy for electrical parameters during switching and in off-grid mode. This strategy dynamically adjusts the output of the PCS to counteract disturbances caused by power switching and load changes, firmly stabilizing the power supply parameters within the allowable range. This feature directly overcomes the defect of "unstable power supply parameters," ensuring that the load equipment does not interrupt operation due to sudden voltage drops or frequency shifts during switching and subsequent operation. This is the key technology for achieving "no power outage detection."

[0030] Specifically, this application completes a full power supply protection closed loop by monitoring the recovery status of the main power supply and controlling the grid-connected energy storage converter (PCS) to smoothly switch back to grid-connected mode. This not only ensures the continuity of power supply during the fault period but also ensures the smooth reconnection of the system after the grid returns to normal, demonstrating the completeness of the method.

[0031] Furthermore, this application introduces a "pre-synchronization control algorithm" and a "fast power compensation algorithm" as specific implementations of the closed-loop control strategy for electrical parameters. Based on the defined pre-synchronization control algorithm, the output voltage and frequency of the grid-connected energy storage converter (PCS) are precisely tracked and controlled, ensuring that its output remains highly synchronized with the main grid or the expected value of the load during switching or off-grid operation, greatly reducing closing impact or operational fluctuations. The defined fast power compensation algorithm can quickly calculate and compensate for the required power according to load changes, effectively suppressing voltage fluctuations caused by load switching, and further consolidating the power supply stability during off-grid operation.

[0032] Furthermore, this application implements dynamic operation strategy adjustments through an energy management system (EMS) based on an objective function that optimizes the real-time operating cost of the grid-connected energy storage power station, the state of charge (SOC) compliance rate of the energy storage, and the load power fluctuation coefficient. An improved particle swarm optimization algorithm is used for efficient solution, enabling the system to not only perform well during fault switching but also intelligently optimize its operating status during off-grid independent power supply. This ensures power supply reliability while also taking into account economy and equipment lifespan, thereby improving the overall performance of the system.

[0033] Furthermore, this application achieves phase synchronization through a smooth synchronization algorithm before grid connection switching, effectively avoiding potential power surges to the grid and its own equipment during grid connection restoration. This ensures the safety and reliability of the operation at the end of the entire power supply guarantee process, and is an extension of the "seamless" concept in the grid connection process.

[0034] Other beneficial effects of the present invention will be further described below. Attached Figure Description

[0035] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1This is a flowchart illustrating the steps of one embodiment of this application. Detailed Implementation

[0036] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] This application discloses a seamless switching control method for a grid-connected energy storage power station. By monitoring the status of the main power supply in real time, in the event of a fault, a seamless switching between off-grid and grid-connected modes is achieved in milliseconds using control logic based on pre-synchronization control and fast power compensation algorithms, ensuring uninterrupted power supply to the load; and smooth grid connection is achieved after grid recovery. Furthermore, the energy management system (EMS) dynamically adjusts the operating strategy based on an objective function that optimizes the real-time operating cost of the grid-connected energy storage power station, the state of charge (SOC) achievement rate of the energy storage, and the load power fluctuation coefficient. This not only meets the uninterrupted power supply requirements of the load but also actively supports grid frequency and voltage stability. This method solves the problems of slow response and limited functionality of traditional emergency power supplies, achieving millisecond-level seamless switching and stable power supply in critical scenarios.

[0039] In some embodiments, a sensorless conversion control method for a grid-connected energy storage power station includes the following steps: Step 1: Construct a 10 kV high-voltage direct-connection grid-type energy storage system.

[0040] A 10 kV high-voltage direct-connection real-time online grid-type energy storage system was constructed, consisting of 41 sets of core equipment. The core equipment includes 20 prefabricated cabins (3 meters high and 6-10 meters long) that integrate off-grid and on-grid control, energy storage and conversion, relay protection and fire protection functions, forming multiple sets of "super power bank" type energy storage units. The energy storage system is directly connected to the 10 kV high-voltage busbar on the venue side, without the need for transformer conversion. The system configuration includes: Cell layer: Lithium iron phosphate cells are selected, and the charging and discharging efficiency and stability of the cells are ensured through full-process consistency control; Converter layer: The grid-connected energy storage converter PCS is adopted, which has the ability to actively adjust the grid frequency and voltage. It can provide "stabilizer" support for the grid when the grid fluctuates. Specifically, unlike conventional grid-connected converters that rely on grid voltage / frequency reference and passively track grid status, the grid-connected energy storage converter PCS of this application adopts virtual synchronous machine (VSG) + droop control technology. By simulating the inertia, damping and droop characteristics of synchronous generator, it actively supports grid frequency / voltage and can operate independently without relying on grid reference, thus having stronger grid support capability and operational flexibility. Energy Management Layer: Based on the Energy Management System (EMS), it adopts a "cloud + terminal" cockpit architecture to realize real-time monitoring of the energy storage system's operating status and dynamic adjustment of charging and discharging strategies; Fire protection floor: Equipped with a dual three-dimensional fire protection system of "water + gas" to ensure the safe operation of the energy storage unit.

[0041] Step 2: Establish a comprehensive quality control system.

[0042] A comprehensive quality control system is established across seven dimensions: raw materials, equipment components, system design, manufacturing, installation and commissioning, handover and acceptance, and grid connection. Details are shown in Table 1 below. Table 1

[0043] Step 3: Develop a transportation support plan for energy storage equipment.

[0044] To address the long-distance transportation needs of energy storage equipment from the production site to the application site (such as a sports venue), a precise and controlled transportation plan should be developed: Monitoring aspect: Each energy storage device is equipped with all-around gravity, tilt, and temperature sensors to monitor the equipment status in real time during transportation; Protection measures: A dual protection structure of "external 360-degree buffer pad + internal damping fixation" is adopted to reduce the impact of transportation vibration on the equipment, as detailed below: 1. External 360-degree cushioning pad.

[0045] Structure: It adopts a modular splicing design, which completely wraps the outer wall of the prefabricated energy storage cabin (including the top, bottom and four sides). The splicing joints are sealed with snap-fit, with no blind spots.

[0046] Materials: The core layer is high-density EVA foam material (Shore hardness 45±5°), the outer layer is composite flame-retardant Oxford cloth (flame retardant grade GB8624-2012B1), and the inner layer is bonded with anti-slip rubber pads.

[0047] Parameters: The size of a single buffer pad is 1m×0.5m×15cm (length×width×thickness), and the overall buffer layer thickness after splicing is uniform ≥15cm; the compression rebound rate is ≥90% (under 25% compression), and the impact absorption performance is ≥80% (to cope with impacts of less than 5g during transportation).

[0048] 2. Internal damping is fixed.

[0049] Structure: The prefabricated cabin adopts a "four-point damping bracket + transverse tie rod reinforcement" structure. Damping shock absorbers are installed at the four corners of the bottom of the cabin, and transverse damping tie rods are installed between the side walls and the core equipment (battery cluster, PCS cabinet).

[0050] Materials: The core of the damping shock absorber is a composite structure of natural rubber and metal spring, and the tie rod is made of high-strength aluminum alloy (tensile strength ≥300MPa) with anodized surface treatment.

[0051] Parameters: Damping shock absorber rated load 50kN / unit, damping coefficient 0.3~0.5, natural frequency 5~8Hz; transverse tie rod preload 15~20kN, can absorb ±15° tilt and high frequency vibration (≤50Hz) during transportation, and the displacement after the equipment is fixed is ≤2mm.

[0052] Speed ​​control: The transport vehicle speed will be controlled within 80 km / h throughout the entire process to avoid excessive equipment swaying caused by high-speed driving; Environmental adaptability: Based on the adaptability range of parameters such as equipment temperature and tilt angle, the transportation route and timeliness are dynamically adjusted to ensure that the parameters of the equipment are within a safe range throughout the entire transportation process.

[0053] Step 4: Achieve seamless switching and rapid power restoration.

[0054] The energy storage system is preset with two operation modes: grid-connected and off-grid. It monitors the status of the main power supply in real time. The specific conversion and recovery process is as follows: Normal operating conditions: The energy storage system is in grid-connected operation mode, connected to the 10 kV high-voltage bus, actively adjusting the grid frequency and voltage to assist in the stable operation of the grid; Fault Trigger: When a main power supply malfunction is detected (voltage / frequency exceeds preset threshold), the system triggers an off-grid operation mode switching command; Millisecond-level switching: The grid-connected energy storage converter PCS completes seamless switching between grid-connected and off-grid modes within 5 milliseconds, and the energy storage system independently takes over the power supply to the venue, achieving uninterrupted and imperceptible power supply switching; Continuous power supply: After switching, the energy storage system supplies power to the venue in off-grid operation mode, which can meet the uninterrupted power supply needs for nearly 3 hours under the maximum power operation conditions during the closing ceremony performance; Grid restoration: Once the main power supply has stabilized, the system will smoothly switch back to grid-connected operation mode while ensuring stable power supply.

[0055] It is understandable that the core of restoring the stability of the main power supply lies in its three key electrical parameters: voltage, frequency, and phase. These parameters must continuously meet preset thresholds and industry standard requirements, without abnormal fluctuations. For example, voltage change rate ≤ 2% / s, frequency change rate ≤ 2Hz / s, and phase ( (Difference ≤ 5°, etc.)

[0056] In some implementations, the energy storage system is preset with two modes: grid-connected operation and off-grid operation. It monitors the status of the main power supply in real time, and the specific control logic for the 5-millisecond seamless switching is implemented through the following formulas and algorithms: Main power supply fault detection logic: Real-time acquisition of voltage amplitude of the main power supply ,frequency , and the preset threshold (voltage threshold) Frequency threshold In comparison, the fault determination formula is:

[0057] in: This is a fault identification indicator; 1 indicates a main power supply failure, and 0 indicates normal operation. The voltage tolerance threshold is set to a value of [value to be filled in]. (correspond The power grid is ); The frequency tolerance threshold is set to a value of [value to be filled in]. (Strict power supply standards for the event); Data sampling frequency is (i.e., each) (One sample), triggered by two consecutive samples If the fault is detected, immediately initiate the off-grid handover command; fault determination takes time. 2ms.

[0058] Millisecond-level offline handover control logic: The off-grid switching of the grid-connected energy storage converter (PCS) adopts pre-synchronization control + fast power compensation algorithm. After the switching command is issued, the tracking formula for the PCS output voltage / frequency is as follows:

[0059]

[0060] in: , Let t represent the voltage and frequency output by the PCS. This is the voltage proportionality coefficient, with a value of 100 (dimensionless). This is the frequency proportionality coefficient, with a value of 50 (dimensionless). Integral time constant Ensure voltage / frequency tracking without overshoot; During the switching process, the formula for compensating the output power of the energy storage system is as follows:

[0061] in: The real-time load power of the venue is predicted by combining pre-stored load curves with real-time sampling, with an error margin of [missing information]. 2%; Output power before the main power supply failure; This is the power compensation factor, with a value of 1.05, to ensure uninterrupted power supply to the load. This represents the real-time output power of the grid-type energy storage converter (PCS) at time t.

[0062] In some embodiments, the specific steps of the pre-synchronization control + fast power compensation algorithm are as follows: Pre-synchronization preparation: After fault determination, the PCS immediately starts the pre-synchronization mode and reads the voltage / frequency / phase data before the power grid fault as the initial tracking reference.

[0063] Parameter tracking adjustment: Based on the voltage / frequency tracking formula, through proportional-integral control (K_U=100, K_f=50, τ=1ms), the PCS output quickly approaches the set value without overshoot deviation.

[0064] Load power prediction: By combining pre-stored load curves with real-time sampling (error ≤ 2%), the current load power P_load (t) of the venue is accurately predicted.

[0065] Power compensation output: Based on the power compensation formula (K_P=1.05), it supplements the power gap before the main power supply failure, ensuring that P_PCS(t) matches the load demand in real time without power interruption.

[0066] Switching confirmation closed loop: Real-time monitoring of PCS output and load matching degree. When voltage sag ≤3% and frequency fluctuation ≤±0.1Hz, the switching is confirmed to be complete and the system enters the stable off-grid operation state.

[0067] The above control logic is implemented through FPGA hardware circuitry, with instruction execution delay... Combined with fault diagnosis Total time spent on offline handover To achieve "seamless switching" (voltage sag of venue electrical equipment) Frequency fluctuation (No power outage detection).

[0068] It should be noted that the core reason for choosing FPGA hardware circuits to implement the above control logic is that its parallel computing architecture can simultaneously handle multi-dimensional control tasks such as voltage / frequency tracking and power compensation, with an instruction execution latency of ≤1ms. Compared with the serial processing mode of DSP, it can better meet the microsecond-level timing control requirements and provide hardware support for 5-millisecond seamless switching.

[0069] The determination of "no power outage detection" is based on the event equipment tolerance standards and the IEEE 1159 power system transient standard: voltage sag ≤3% (duration ≤5ms) and frequency fluctuation ≤±0.1Hz, both of which are lower than the tolerance thresholds of large-scale sports event equipment (lighting, sound, broadcasting equipment, etc.) (voltage sag ≤5% and frequency fluctuation ≤±0.2Hz), ensuring that the equipment has no abnormal response.

[0070] Grid connection switching logic after grid restoration: When detected And the main power supply is operating stably. When switching to grid connection is initiated, a smooth synchronization algorithm is used:

[0071] in: , The phase angle between the PCS output voltage and the mains voltage; This is the phase compensation coefficient, with a value of 20 (dimensionless), representing the phase synchronization time. After synchronization, it connects smoothly to the grid without power surge.

[0072] Step 5: Real-time monitoring and dynamic optimization of system operation Through the "cloud + terminal" cockpit architecture of the EMS system, data such as the charging and discharging status of the energy storage system, cell temperature, and grid parameters (frequency / voltage) are collected in real time. The operating strategy of the energy storage system is dynamically adjusted according to different power consumption conditions during the event (such as peak performance and equipment standby) to ensure optimal power supply stability and energy efficiency.

[0073] A "cloud + edge" cockpit-style EMS system is adopted, and the dynamic adjustment strategy algorithm is implemented based on a multi-objective optimization model of real-time operating conditions. In some implementations, the optimization objective function of the EMS system is as follows:

[0074] in: The real-time operating cost of the energy storage system (RMB / kWh) includes battery cycle loss cost and auxiliary control system energy consumption cost; The target value is the energy storage state of charge (SOC) compliance rate. , ;

[0075] The power fluctuation coefficient of the venue. ;

[0076] This is a weighting coefficient, representing peak times of the event (performances and competition segments). Off-peak hours .

[0077] In some implementations, the constraints for dynamically adjusting the strategy are as follows:

[0078]

[0079]

[0080] in: This refers to the charging / discharging power. For charging and discharging efficiency, ; (Ensuring uninterrupted power supply for 3 hours).

[0081] In some implementations, the optimization algorithm is solved as follows: An improved particle swarm optimization (PSO) algorithm is used to solve the above objective function. The particle dimensions include: PCS output power, charging / discharging time, and SOC target value. The iterative update formula is as follows:

[0082]

[0083] in: For inertia weights, an adaptive adjustment strategy is adopted: ( Maximum number of iterations (value 50). As a learning factor, A random number in the range [0, 1]. Iteration termination condition: the convergence accuracy of the objective function value 0.001, iteration time This ensures that the EMS system updates its operating strategy every second to adapt to dynamic changes in venue load.

[0084] It should be noted that this application employs an improved particle swarm optimization (PSO) algorithm, the core improvement of which lies in the adaptive adjustment strategy of inertia weight: ( (Maximum number of iterations), compared to the fixed inertia weight of standard PSO, it can dynamically balance global search and local convergence capabilities, improve the accuracy and efficiency of objective function solution, and ensure that the optimal running strategy is output within 100ms.

[0085] In some embodiments, a grid-type energy storage power station for power supply is also provided, comprising: one or more prefabricated cabins; a grid-type energy storage converter (PCS) disposed within the prefabricated cabin and configured to execute the sensorless conversion control method of this application; an energy storage battery electrically connected to the PCS; an energy management system (EMS) communicatively connected to the PCS and configured to monitor the operating status of the energy storage power station and send control commands; and a fire suppression system disposed within the prefabricated cabin.

[0086] In some embodiments, the grid-type energy storage converter (PCS) is a high-voltage direct-connected converter, configured to be directly connected to the high-voltage bus on the load site side.

[0087] In some embodiments, the prefabricated cabin integrates a grid-connected and off-grid control unit, an energy storage and conversion unit, a relay protection unit, and a fire protection unit.

[0088] In some embodiments, the energy storage battery includes a lithium iron phosphate battery; the fire protection system includes a water-air dual-stage fire protection system.

[0089] In some embodiments, a grid-type energy storage converter PCS is also provided, comprising: a processor and a memory; the memory stores a computer program; when the processor executes the computer program, it implements the sensorless conversion control method of this application.

[0090] In some embodiments, a power supply system is also provided, comprising: a main power supply; a grid-type energy storage power station of this application, which is connected to the same power grid as the main power supply via a high-voltage bus; and a load powered by the main power supply or the grid-type energy storage power station; wherein the grid-type energy storage power station is configured to perform seamless transfer control to provide uninterrupted power supply to the load in the event of a failure of the main power supply.

[0091] In some embodiments, a computer-readable storage medium is also provided, on which a computer program / instruction is stored, which, when executed by a processor, implements the seamless switching control method of this application.

[0092] The following will further describe specific embodiments of the present invention. These embodiments are merely illustrative and do not mean that the present invention is limited to the following examples.

[0093] Example: Emergency power supply application for the closing ceremony of the 15th National Games Step 1: Energy storage system construction.

[0094] A 10 kV high-voltage direct-connection real-time online grid-type energy storage system was built for the closing ceremony of the 15th National Games. The system includes 41 sets of core equipment, of which 20 prefabricated cabins integrate grid-connected and off-grid control, energy storage and conversion, relay protection, and fire protection functions. The prefabricated cabins are 3 meters high and 6-10 meters long, forming 4 sets of "super power bank" energy storage units. The system uses lithium iron phosphate cells and is equipped with a grid-type PCS, a "cloud + terminal" cockpit-style EMS, and a "water + gas" dual three-dimensional fire protection system, which is directly connected to the 10 kV high-voltage busbar of the closing ceremony venue.

[0095] The specific composition of the 41 sets of core equipment is shown in Table 2.

[0096] Table 2

[0097] The compositional relationship between the prefabricated module and the energy storage unit is as follows: Composition logic: The 20 prefabricated cabins are configured as "5 units / set", and divided into 4 independent "super power bank" energy storage units (5 cabins × 4 sets = 20 units). Unit Composition: Each energy storage unit consists of 5 prefabricated modules (energy storage core) + 1 grid-type PCS (control core), with matching sensor kits and auxiliary control cabinets to achieve coordinated operation; System level: 4 sets of energy storage units are connected in parallel to the 10 kV high-voltage bus, and are uniformly managed by 1 EMS system, forming an energy storage system with 41 sets of core equipment.

[0098] Step 2: Implementation of quality control.

[0099] A comprehensive quality control system was established for this energy storage system: during the raw material stage, the capacity, internal resistance and other parameters of the lithium iron phosphate cells were 100% verified; during the manufacturing stage, more than 10 on-site experiments were conducted to verify the consistency of the cells and optimize the battery compartment structure to improve charging and discharging efficiency; during the installation and commissioning stage, more than 100 grid fault scenarios were simulated and the off-grid switching logic was debugged to ensure that the conversion response time is ≤5 milliseconds.

[0100] Step 3: Equipment transportation support.

[0101] The energy storage equipment production site is far from Shenzhen. To ensure transportation safety, each set of equipment is equipped with gravity, tilt, and temperature sensors to transmit data to the monitoring platform in real time. Double protection is adopted with external buffer pads (15cm thick) and internal damping brackets. The transport vehicles are equipped with speed limiters, and the speed does not exceed 80 km / h throughout the journey. The transportation route avoids high-temperature and bumpy road sections, and the equipment finally arrived at the Shenzhen closing ceremony venue with zero failures.

[0102] Step 4: Seamless transition and power restoration.

[0103] During the closing ceremony, the energy storage system monitored the status of the main power supply in real time: when a simulated main power supply failure occurred, the system completed the off-grid mode switch within 4.8 milliseconds, and the energy storage system provided independent power supply, with no power outage detected in the venue's electrical equipment; after the switch, the system operated at maximum power and provided power continuously for 2 hours and 58 minutes, with voltage and frequency always remaining within the range required by the event; after the main power supply was restored, the system smoothly switched back to grid-connected mode, with no power supply fluctuations throughout the entire process.

[0104] Peak hours of the closing ceremony performance (load power) ), simulating the main power supply voltage drop to (deviation Fault determination time PCS switching command execution time Overall switching time The venue voltage temporarily dropped. Frequency fluctuation The stage lighting, sound and other equipment operated without any interruption or abnormality, achieving a "seamless transition".

[0105] Step 5: Real-time monitoring and optimization.

[0106] Through the EMS "cloud + terminal" cockpit, the system monitored in real time that the venue's power increased by 30% during the peak period of the closing ceremony performance. The system automatically adjusted the energy storage discharge strategy to increase the discharge power and ensure the stable operation of the performance equipment. During the breaks between performances, the system switched to charging mode to supplement the energy storage by utilizing the off-peak electricity of the power grid and improve the overall energy efficiency.

[0107] Performance breaks (load power) The EMS system maintains the SOC at 80% through an optimization algorithm, and adjusts the charging power to... Reduced operating costs During peak performance periods, the system immediately switches to a power-priority strategy, with the PCS output power tracking load fluctuations and the power fluctuation coefficient. The power supply stability meets the requirements of the competition.

[0108] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0109] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0110] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0111] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0112] The background section of this invention may include background information about the problems or environment in which the invention is being developed, and is not necessarily a description of prior art. Therefore, the content included in the background section does not constitute an admission of prior art by the applicant.

[0113] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A sensorless switching control method for a grid-type energy storage power station, wherein the grid-type energy storage power station includes a grid-type energy storage converter (PCS), characterized in that, The method includes the following steps: Monitor the electrical parameters of the main power supply, and determine whether the main power supply has failed based on the comparison results of the electrical parameters with preset thresholds; When a fault is detected in the main power supply, an off-grid switching command is generated; In response to the off-grid switching command, the grid-connected energy storage converter (PCS) is controlled to switch from grid-connected operation mode to off-grid operation mode within milliseconds, so that the grid-connected energy storage power station can independently supply power to the load. During the switching process, a closed-loop control strategy for electrical parameters is adopted to keep the power supply parameters stable, and the load is not affected by power outages. Monitor the recovery status of the main power supply, and when the main power supply stabilizes, control the grid-type energy storage converter PCS to switch from off-grid operation mode back to grid-connected operation mode.

2. The method according to claim 1, characterized in that, The closed-loop control strategy for the electrical parameters includes a pre-synchronization control algorithm and a fast power compensation algorithm.

3. The method according to claim 1, characterized in that, The electrical parameters include voltage and frequency. Based on the comparison results of the electrical parameters with preset thresholds, it is determined whether the main power supply has failed, which is achieved by the following formula: in, This is a fault identification indicator; 1 indicates a main power supply failure, and 0 indicates normal operation. This is the voltage tolerance threshold. This is the permissible frequency deviation threshold; and These are the real-time voltage and frequency of the main power supply, respectively; and These are the voltage threshold and the frequency threshold, respectively; when the fault flag calculated from multiple consecutive samples is 1, it is determined that the main power supply has failed.

4. The method according to claim 2, characterized in that, The pre-synchronization control algorithm achieves tracking control of the output voltage and frequency of the grid-type energy storage converter PCS through the following formula: in, , The voltage and frequency output by the grid-type energy storage converter PCS at time t are respectively. and These are the voltage threshold and the frequency threshold; This is the voltage proportionality coefficient. This is the frequency scaling factor; and These are the real-time voltage and frequency of the main power supply, respectively.

5. The method according to claim 2, characterized in that, The fast power compensation algorithm is implemented using the following formula: in: This represents the real-time load power of the load. The output power before the main power supply failure; This is the power compensation coefficient; This represents the real-time output power of the grid-type energy storage converter (PCS) at time t.

6. The method according to claim 1, characterized in that, After switching to off-grid operation mode, dynamic operation strategy adjustment is performed through the energy management system (EMS). The dynamic operation strategy adjustment is based on solving an objective function with the real-time operating cost of the grid-connected energy storage power station, the state of charge (SOC) compliance rate of the energy storage, and the load power fluctuation coefficient as optimization objectives, so as to optimize the operation of the grid-connected energy storage power station.

7. The method according to claim 6, characterized in that, The objective function for adjusting the dynamic operation strategy is: in, The real-time operating cost of the energy storage system includes battery cycle loss costs and auxiliary control system energy consumption costs; The State of Charge (SOC) compliance rate for energy storage; This refers to the load power fluctuation coefficient. These are the weighting coefficients.

8. The method according to claim 7, characterized in that, The objective function is solved using an improved particle swarm optimization algorithm, and the iterative update formula of the improved particle swarm optimization algorithm is as follows: in, For particle velocity, For particle position, As inertia weights, an adaptive adjustment strategy is adopted. , As a learning factor, A random number in the range [0, 1] This represents the optimal position in the history of an individual particle. This represents the best historical position for the entire population.

9. The method according to claim 1, characterized in that, Switching from off-grid operation mode back to grid-connected operation mode includes the following steps: Phase synchronization is achieved using a smooth synchronization algorithm, followed by grid-connected switching to avoid power surges. The formula for the smooth synchronization algorithm is as follows: in, , The phase angle between the output voltage of the grid-type energy storage converter PCS and the main power supply voltage; This is the phase compensation coefficient.

10. A grid-type energy storage power station for power supply guarantee, characterized in that, include: One or more prefabricated cabins; a grid-type energy storage converter (PCS) disposed within the prefabricated cabin and configured to perform the sensorless conversion control method according to any one of claims 1 to 9; an energy storage battery electrically connected to the grid-type energy storage converter (PCS); an energy management system (EMS) communicatively connected to the grid-type energy storage converter (PCS) and configured to monitor the operating status of the energy storage power station and send control commands; and a fire protection system disposed within the prefabricated cabin.

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