A portable energy storage power supply off-line grid-connected detection and expansion system

Abstract

The application belongs to the technical field of energy storage, and particularly relates to a portable energy storage power supply off-line grid-connected detection and expansion system, which comprises a power grid access module, a multi-rate power grid state detection module, a central control module, an adaptive isolation module, an energy management module, an expansion battery interface module and a man-machine interaction and communication module; the multi-rate power grid state detection module is used for simultaneously providing an ultrafast response to transient abnormality of a power grid and accurate monitoring of steady-state parameters of the power grid, and comprises a transient abnormality fast detection submodule and a comprehensive parameter accurate detection submodule; the adaptive isolation module is directly associated with the transient abnormality fast detection submodule. Through a hardware acceleration detection mechanism of the transient abnormality fast detection submodule and a high-speed solid-state relay array of the adaptive isolation module, the system can respond to transient overvoltage, fast frequency deviation or zero-crossing abnormality and complete an isolation action.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology, specifically a portable energy storage power supply offline grid connection detection and expansion system. Background Technology

[0002] With the global energy transition and the growing consumer demand for flexible power sources, portable energy storage power supplies are widely used in outdoor, emergency, and remote operation scenarios. The core is efficient energy storage and conversion, as well as safe and intelligent interaction with the power grid. During charging, it is necessary to accurately identify the power grid status to ensure the stability and lifespan of the equipment.

[0003] In existing technologies, offline grid connection detection systems are the mainstream solution for the safe connection of energy storage power sources to the power grid. They collect grid parameters through voltage / current sensors and frequency detection modules, and after being digitized by ADC, they are analyzed and judged by microcontrollers / DSPs. If the parameters exceed the threshold or the power grid fails, the actuators realize the grid connection / off-grid switching of the energy storage power source. It can cope with the normal grid fluctuations and steady-state grid connection requirements, and meet the basic requirements for early safe grid connection.

[0004] However, there is a 10-100ms delay throughout the entire process of grid parameter acquisition, signal processing, and command transmission (due to periodic sensor sampling, ADC time consumption, and control unit calculation cycle). This delay can easily cause problems in complex grid dynamic changes: First, when there is a sudden surge in the grid (such as a voltage spike of 300V within 10ms followed by a return to normal), the system cannot detect it in time, causing the extended battery pack to experience short-term overvoltage. Long-term accumulation will accelerate battery degradation, shorten lifespan, and increase safety hazards; Second, when there is a sudden power outage, if the delay exceeds 200ms, the energy storage power supply or extension system cannot be isolated from the grid in time, easily forming an island effect and posing a risk of electric shock to grid maintenance personnel. Existing systems rely on a sequential sampling and serial processing architecture, which makes it difficult to balance extremely high real-time performance with normal operational stability. Therefore, this invention provides a portable energy storage power supply offline grid-connected detection and extension system. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0006] The technical solution adopted by this invention to solve its technical problem is as follows: A portable energy storage power supply offline grid connection detection and expansion system, characterized in that it includes: a grid access module, a multi-rate grid status detection module, a central control module, an adaptive isolation module, an energy management module, an expansion battery interface module, and a human-machine interaction and communication module. These modules are interconnected via a high-speed data bus and dedicated control signal lines, working collaboratively to achieve rapid offline grid connection detection and secure isolation of the power grid.

[0007] The grid connection module serves as the physical interface for the portable energy storage power supply to electrically connect to the external AC power grid. This module includes an AC input socket conforming to International Electrotechnical Commission (IEC) standards, with a rated voltage range of 100V to 240V AC and a rated frequency of 50Hz / 60Hz. The socket is connected to an adaptive isolation module via an internal high-voltage conductor.

[0008] The multi-rate power grid condition detection module is the core innovation of this invention, designed to simultaneously provide ultra-fast response to power grid transient anomalies and accurate monitoring of power grid steady-state parameters. This module is further divided into a rapid transient anomaly detection submodule and a comprehensive parameter accurate detection submodule.

[0009] The transient anomaly rapid detection submodule is used to detect rapid changes in grid voltage, drastic frequency fluctuations, and zero-point crossing anomalies within sub-millisecond timeframes. This submodule includes:

[0010] First, the transient overvoltage detection circuit: This circuit consists of a set of high-precision, low-latency analog comparators, such as rail-to-rail comparators with nanosecond-level response times (e.g., comparator model LM2903 or equivalent). The inputs of the comparators are connected to the mains voltage signal, which has been precisely divided and filtered. The precision voltage divider network consists of a series resistor array (e.g., multiple 1MΩ, 0.1% accuracy, 0.25W metal film resistors connected in series) and parallel sampling capacitors (e.g., multiple 1nF, 1000V rated ceramic capacitors connected in parallel), designed to proportionally attenuate the high-voltage AC signal to an acceptable input range for the comparators (e.g., 0V to 5V). The filtering circuit includes a passive RC filter with a cutoff frequency of 10kHz to remove high-frequency noise while retaining transient voltage change information. The comparators are set with multiple preset fixed reference voltage thresholds, such as peak voltages corresponding to the AC RMS values ​​of 270V, 280V, 300V, and 320V of the mains voltage. When the instantaneous amplitude of the grid voltage signal after voltage division and filtering exceeds any preset threshold, the corresponding comparator output will immediately flip. The comparator output is directly connected to a high-priority interrupt controller or a dedicated hardware logic gate array (e.g., fast-response logic integrated in an FPGA). Upon receiving any comparator output flip signal, the logic gate array will immediately generate a trigger signal with a response delay of less than 0.5 milliseconds.

[0011] Second, a fast frequency deviation detection circuit: This circuit consists of a high-speed zero-crossing detector and a frequency tracking and comparison unit based on a digital phase-locked loop (DPLL). The zero-crossing detector uses optocoupler isolation technology (e.g., PC817 series optocouplers) to convert the AC mains voltage into a square wave signal, where the rising and falling edges of the square wave signal correspond to the zero-crossing of the AC voltage, respectively. The square wave signal is input to the DPLL module of an FPGA or dedicated digital ASIC. The DPLL module has a configurable fast lock-in time (e.g., less than 5 milliseconds) and high-resolution frequency measurement capability. The DPLL module continuously tracks the mains frequency and compares it with an internally set nominal frequency (e.g., 50.00 Hz or 60.00 Hz). When the frequency detected by the DPLL deviates from the nominal frequency by more than a preset threshold (e.g., ±2 Hz) within a short time window (e.g., within 5 consecutive mains cycles), the DPLL module generates a frequency anomaly trigger signal. This trigger signal is also directly connected to the high-priority interrupt controller or dedicated hardware logic gate array.

[0012] Third, the zero-crossing behavior anomaly detection circuit: This circuit shares the square wave signal output by the zero-crossing detector with the fast frequency deviation detection circuit. This submodule monitors the time interval between consecutive zero-crossing events and the continuity of the zero-crossing signal. When a significantly abnormal time interval between consecutive zero-crossings is detected (e.g., exceeding 1.5 times the normal period) or the zero-crossing signal completely disappears within a certain time (e.g., 10 milliseconds), it indicates that the power grid may experience a power outage or severe waveform distortion. This anomaly detection logic is implemented by an FPGA or a dedicated digital ASIC, which outputs a zero-crossing anomaly trigger signal with a response delay of less than 1 millisecond.

[0013] All the trigger signals of the aforementioned transient anomaly rapid detection submodule are aggregated into one or more dedicated high-speed OR gate arrays. The aggregated output signal is directly used as the direct tripping command input of the adaptive isolation module, ensuring that the system can initiate isolation action in a very short time (e.g., less than 1 millisecond) when a severe transient anomaly occurs.

[0014] The comprehensive parameter precision detection submodule is used for high-precision, multi-cycle, steady-state digital acquisition and analysis of parameters such as grid voltage, current, frequency, and phase. This submodule includes:

[0015] First, high-precision voltage and current sensors: Hall effect voltage sensors (e.g., LEMLV25-P type or equivalent, with linearity better than 0.1% and bandwidth greater than 50kHz) and Hall effect current sensors (e.g., LEMLA55-P type or equivalent, with linearity better than 0.1% and bandwidth greater than 50kHz) are used to acquire the voltage and current waveforms of the power grid in real time. These sensors provide isolated analog output signals proportional to the input voltage / current.

[0016] Second, a multi-channel synchronous analog-to-digital converter (ADC): employing a multi-channel, high-resolution (e.g., 16-bit or higher), high-sampling-rate (e.g., at least 100 kHz per channel) synchronous sampling ADC (e.g., ADS8688 or its equivalent). This ADC converts the analog signal output from the sensor into a digital signal, ensuring a high degree of synchronization between voltage and current sampling points for accurate calculation of power factor and phase angle.

[0017] Third, a digital signal processor (DSP): The digital output data stream of the ADC is transmitted to a dedicated DSP (e.g., a TIC2000 series or equivalent) via a high-speed serial interface (e.g., SPI or LVDS). The DSP has an embedded high-performance floating-point unit that executes the following real-time algorithms:

[0018] A1. Effective Value (RMS) Calculation: A sliding window RMS calculation is performed on voltage and current sampling data from multiple power grid cycles to obtain stable and accurate effective values.

[0019] A2. Precise Frequency and Phase Detection: Employing zero-point cross-detection combined with Kalman filtering algorithm or frequency estimation algorithm based on Discrete Fourier Transform (DFT), the system achieves 0.01Hz-level accuracy measurement of the power grid frequency and accurately determines the phase angle between voltage and current.

[0020] A3. Harmonic Analysis: By performing spectral analysis on voltage and current waveforms using Fast Fourier Transform (FFT), the harmonic content is identified and quantified to assess the power quality of the power grid.

[0021] A4. Power Grid Status Judgment: Based on the above calculation results, the DSP compares parameters such as power grid voltage, frequency, phase angle, and harmonic distortion rate (THD) with international standards (e.g., IEC61000 series) and preset safe operating thresholds to generate a detailed power grid status report.

[0022] The response delay of the comprehensive parameter precision detection submodule is in the range of 10 milliseconds to 50 milliseconds. The detailed grid status data it outputs is transmitted to the central control module through a high-speed data bus. This data is used to guide the energy management module in adjusting charging strategies, diagnosing faults, and recording logs. It also serves as the basis for the adaptive isolation module to release isolation or reconnect to the grid.

[0023] The central control module, acting as the intelligent decision-making center of the entire system, coordinates and manages the operation of all sub-modules. This module includes: a high-performance microcontroller (MCU, for example, a microcontroller based on an ARM Cortex-M4 or M7 core with a clock frequency of not less than 200MHz), an embedded real-time operating system (RTOS), and non-volatile memory (e.g., EEPROM or NAND Flash) for storing system configuration, operation logs, and firmware programs.

[0024] The central control module receives direct trip commands (as high-priority interrupts) from the transient anomaly rapid detection submodule and detailed grid status data from the comprehensive parameter precise detection submodule, and makes decisions based on preset control strategies and safety logic. Upon receiving a trip command from the transient anomaly rapid detection submodule, the central control module immediately issues a forced isolation command to the adaptive isolation module, records the event log, and notifies the energy management module to stop charging. When the grid status returns to normal and is confirmed stable by the comprehensive parameter precise detection submodule, the central control module issues reconnection commands to the adaptive isolation module in stages according to preset delay and safety protocols. Furthermore, the central control module is also responsible for managing the charging / discharging strategy of the energy management module, the power distribution of the extended battery interface module, and the data exchange of the human-machine interface and communication modules. The firmware running on the microcontroller implements complex finite state machine (FSM) control logic to ensure the determinism and reliability of system behavior under various grid operating conditions.

[0025] The adaptive isolation module is designed to achieve rapid and reliable physical isolation between the portable energy storage power supply and the external power grid. This module is the key actuator for achieving millisecond-level security response in this invention, and it includes:

[0026] First, a high-speed solid-state relay (SSR) array: This array consists of multiple sets of AC solid-state relays with high voltage and high current resistance (e.g., a zero-point cross-type SSR with a rated voltage of 800V and a rated current of 30A). Upon receiving a voltage level signal command, the SSR can complete its switching action in less than 1 millisecond, achieving instantaneous disconnection from the power grid. The SSR array is used to respond to direct tripping commands issued by the transient anomaly rapid detection submodule.

[0027] Second, mechanical contactors: One or more high-reliability AC contactors (e.g., rated voltage 250V, rated current 30A, mechanical life greater than 1 million cycles) are connected in series downstream of the SSR array to provide long-term, physically disconnected isolation after the SSR actuates, and have higher short-circuit withstand capability. These mechanical contactors are controlled by a central control module via independent drive circuits (e.g., H-bridge drive circuits), and their actuation time is typically between 10 and 30 milliseconds.

[0028] Third, the overcurrent protection unit integrates high-speed fuses (e.g., ultra-fast fuses with a response time of less than 10 microseconds) and / or magnetic trip circuit breakers to provide ultimate protection in the event of extreme short-circuit faults. The adaptive isolation module is designed with the SSR array providing rapid transient isolation of the main path, followed by long-term physical isolation via mechanical contactors. This fast-then-stable isolation strategy ensures that the energy storage system can escape danger as quickly as possible in the event of any extreme grid transient event, while maintaining absolute physical safety through mechanical contactors during long-term isolation. The module's triggering logic features a hardware priority interrupt mechanism, meaning that any trip command from the transient anomaly rapid detection submodule will bypass the central control module's conventional decision-making process and directly drive the SSR array to trip.

[0029] The energy management module is responsible for managing the charging and discharging process of the internal battery pack of the portable energy storage power supply and for energy interaction with external extended battery packs. This module includes:

[0030] First, the Battery Management System (BMS): This integrates a dedicated battery management IC (e.g., bq76952 or its equivalent) for real-time monitoring of individual cell voltages, total voltage, charge / discharge current, battery temperature, and battery state of health (SOH) and state of charge (SOC) of the internal and extended battery packs. The BMS performs functions such as voltage equalization, overcharge protection, over-discharge protection, overcurrent protection, and over-temperature protection, controlling the charge / discharge path through an N-channel power MOSFET array.

[0031] Second, the AC-to-DC (AC / DC) charger: This charger employs a high-efficiency, power factor correction (PFC) AC / DC conversion topology (e.g., interleaved boost PFC combined with a full-bridge LLC resonant converter) to convert the AC power input from the grid connection module into DC power to charge the battery pack. The charger has programmable output voltage and current capabilities, dynamically adjusted by a central control module based on battery status and grid conditions.

[0032] Third, DC-to-AC inverter: A DC / AC inverter with pure sine wave output (e.g., an H-bridge inverter combined with SPWM control) converts the DC power from the battery pack into AC power to supply power to external loads. The inverter has multiple protection functions, including overload, short circuit, and over-temperature protection.

[0033] The energy management module communicates with the central control module via a CAN bus or a dedicated SPI interface to exchange battery status information and control commands in real time, so as to optimize charging and discharging efficiency and extend battery life.

[0034] The extended battery interface module is used to securely and reliably connect one or more external extended battery packs, thereby increasing the total energy capacity of the portable energy storage power supply. The module includes:

[0035] First, the physical connectors: High-current, low-contact-resistance waterproof and dustproof connectors (e.g., Anderson Powerpole series or their industrial equivalents) ensure a robust electrical connection between the expansion battery pack and the main unit. These connectors incorporate a mechanical foolproof design to prevent mis-insertion.

[0036] Second, the communication interface: a dedicated data pin is integrated inside the connector to establish a CAN bus or UART communication link between the host and the extended battery pack, so that the central control module and the energy management module can obtain the BMS data of the extended battery pack (e.g., voltage, current, temperature, SOC, etc.).

[0037] Third, power management and protection circuitry: including a secondary overcurrent protection circuit and a reverse connection protection diode independent of the main BMS, to ensure the safety of extended battery pack connections and prevent system damage caused by external faults.

[0038] The design of the extended battery interface module allows users to flexibly expand energy storage capacity without affecting the safety performance of the main system. All management data of the extended battery packs are uniformly scheduled by the central control module.

[0039] The human-computer interaction and communication module provides system status display, user input, and external data communication functions. This module includes:

[0040] First, the display unit: adopts a color liquid crystal display screen (e.g., a TFT LCD with a resolution of 320x240 pixels) to display real-time power grid status parameters, battery charging and discharging status, remaining power, fault alarms, and system operating modes.

[0041] Second, the input unit includes multiple physical buttons to prevent accidental touches and / or a touchscreen interface for users to switch modes, query parameters, and set functions.

[0042] Third, wireless communication unit: integrates a Wi-Fi module (e.g., IEEE 802.11b / g / n standard) and / or a Bluetooth module (e.g., Bluetooth Low Energy 5.0 standard) for wireless data exchange, remote monitoring, and firmware upgrades between the portable energy storage power supply and smartphone applications or cloud platforms.

[0043] Fourth, wired communication unit: including USB Type-C interface or Ethernet interface, for local data transmission, diagnostics and programming.

[0044] The human-computer interaction and communication module exchanges data with the central control module through standard communication protocols (e.g., Modbus TCP / IP or MQTT over Wi-Fi) to ensure the accuracy and real-time nature of information.

[0045] The workflow of the portable energy storage power supply offline grid-connected detection and expansion system provided by this invention is as follows:

[0046] When the portable energy storage power supply is connected to the external AC power grid via the grid access module, the multi-rate grid status detection module immediately activates. The transient anomaly rapid detection submodule continuously monitors the instantaneous amplitude and frequency fluctuations of the grid voltage, as well as zero-point crossing behavior, with a sub-millisecond response speed. If a transient overvoltage (e.g., voltage amplitude exceeding 300V), rapid frequency deviation (e.g., frequency deviation from nominal value ±2Hz), or zero-point crossing anomaly (e.g., zero-point signal disappearance exceeding 10 milliseconds) is detected, this submodule immediately generates a direct trip command. This command bypasses the routine processing of the central control module and directly triggers the high-speed solid-state relay array in the adaptive isolation module to disconnect the portable energy storage power supply from the grid in less than 1 millisecond, thereby preventing overvoltage damage to the extended battery pack caused by transient surges and effectively eliminating the safety hazard of islanding. Simultaneously, this trip command notifies the central control module in a high-priority interrupt manner. The central control module then records the event log and instructs the mechanical contactor in the adaptive isolation module to perform physical isolation, providing long-term disconnection protection.

[0047] Meanwhile, the comprehensive parameter precision detection submodule continuously performs high-precision measurement and analysis of parameters such as the effective voltage value, effective current value, precise frequency, phase angle, and harmonic distortion rate of the power grid with a response period of 10 to 50 milliseconds. The DSP generates a detailed power grid status report based on this data and transmits it to the central control module via a high-speed data bus. The central control module uses this detailed data to assess the overall stability and power quality of the power grid and adjusts the charging strategy of the energy management module accordingly. For example, when the power grid voltage fluctuation exceeds the set safe range but does not reach the instantaneous tripping threshold, the charging current is reduced to protect the battery.

[0048] When a power outage occurs, the adaptive isolation module has already completed its rapid tripping. The central control module monitors the grid status from the comprehensive parameter precision detection submodule. Once it confirms that the grid has fully stabilized and all parameters are within safe ranges, the central control module will follow a preset reconnection protocol. This protocol typically includes a configurable delay period (e.g., 300 to 600 seconds) to ensure long-term grid stability. After the delay, the central control module will instruct the AC / DC charger of the energy management module to enter pre-charging mode and, through the mechanical contactors and high-speed solid-state relay array in the adaptive isolation module, reconnect the portable energy storage power supply to the grid in stages and in a controlled manner, restoring its charging function.

[0049] The beneficial effects of this invention are as follows:

[0050] By significantly improving the response speed to power grid transient anomalies—through the hardware-accelerated detection mechanism of the transient anomaly rapid detection submodule and the high-speed solid-state relay array of the adaptive isolation module—the system can respond to and isolate transient overvoltages, rapid frequency deviations, or zero-point crossover anomalies in less than 1 millisecond. This response speed far exceeds the 10 to 100 millisecond delays commonly found in existing technologies, thus completely avoiding overvoltage damage to the extended battery pack caused by transient power grid surges.

[0051] By avoiding the impact of instantaneous high-voltage events on the battery, the irreversible degradation of the internal electrochemical materials of the battery is effectively suppressed, thereby significantly slowing down the battery capacity decay and internal resistance increase, fundamentally extending the cycle life and calendar life of portable energy storage power supplies and their extended battery packs.

[0052] In the event of a sudden power outage, the system of this invention can physically isolate the portable energy storage power source from the power grid at an extremely fast speed (e.g., less than 5 milliseconds, including the total time for detection and isolation), completely eliminating the risk of the energy storage power source feeding power to the de-energized power grid, thereby ensuring the safety of power grid maintenance personnel.

[0053] Through the coordinated operation of the comprehensive parameter precision detection submodule and the central control module, accurate and real-time monitoring and analysis of parameters such as grid voltage, current, frequency, phase and harmonics are ensured. Attached Figure Description

[0054] The invention will now be further described with reference to the accompanying drawings.

[0055] Figure 1 This is the system architecture diagram of the present invention. Detailed Implementation

[0056] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0057] like Figure 1 As shown, this invention discloses a portable energy storage power supply offline grid-connected detection and expansion system, comprising: a grid access module serving as the physical interface for electrical connection between the portable energy storage power supply and the external AC power grid, which integrates an industrial-grade three-phase or single-phase AC input socket conforming to the International Electrotechnical Commission (IEC) 60309 standard. This socket has IP67 protection rating, capable of withstanding dust and moisture intrusion under harsh environmental conditions. Its rated voltage operating range covers 90V to 265V AC RMS, supporting a rated grid frequency of 50Hz / 60Hz. The socket is internally electrically connected to the first-stage protection unit of the adaptive isolation module via a high-voltage conductor. The high-voltage conductor is a pure copper conductor with a cross-sectional area of ​​not less than 4 square millimeters, has a rated withstand voltage of 1000V, and is wrapped with an XLPE (cross-linked polyethylene) insulation layer, while also meeting the low-smoke halogen-free (LSZH) fire-resistant standard to ensure the system's electrical safety and fire resistance under extreme conditions.

[0058] The multi-rate power grid status detection module is the core technical unit of this invention for achieving efficient and safe offline grid-connected detection. Its innovation lies in decomposing the power grid status monitoring task into two parallel and complementary sub-modules: a rapid transient anomaly detection sub-module and a comprehensive parameter accurate detection sub-module.

[0059] The transient anomaly rapid detection submodule is specifically designed to detect sudden and drastic changes in grid voltage, rapid fluctuations in frequency, and abnormal zero-point crossing behavior within sub-millisecond timeframes. This submodule integrates the following three key circuits:

[0060] Firstly, the transient overvoltage detection circuit. This circuit consists of a parallel array of high-precision, ultra-low-delay analog comparators. In a preferred embodiment, four rail-to-rail comparators of the ADI LTC6752 type or equivalent are used. These comparators have a typical propagation delay of 2.9 nanoseconds (ns) and are compatible with digital logic level outputs from 0V to 5V. The inputs of the comparators are connected to a mains voltage signal that has undergone precise voltage division and multi-stage filtering.

[0061] The precision voltage divider network consists of eight 1-megaohm (MΩ) metal film resistors connected in series, each with a 0.1% accuracy and a rated power of 1 watt (W), for a total resistance of 8MΩ. This ensures a stable voltage division ratio and good heat dissipation under high voltage. The parallel sampling capacitor network consists of four 2.2 nanofarad (nF) ceramic capacitors with a rated voltage of 1200V and X7R dielectric material, connected in parallel, for a total capacitance of 8.8nF. This voltage divider network is designed to attenuate AC mains voltages up to 450V peak voltage to a comparator-acceptable input range of 0V to 5V by approximately a 1:500 ratio. The divided signal first passes through a first-order passive RC low-pass filter (e.g., consisting of a 10kΩ resistor and a 1nF capacitor) with a cutoff frequency of 15.9kHz to effectively suppress high-frequency noise and parasitic interference, while ensuring sufficient response bandwidth to transient voltage changes in the mains. The comparator array is set with four independent fixed reference voltage thresholds that precisely correspond to the peak voltages of the mains voltage at 270V, 280V, 300V, and 320V AC RMS. For example, for a 220Vrms mains grid, these peak voltages are 381V, 396V, 424V, and 452V, respectively.

[0062] When the instantaneous amplitude of the grid voltage signal, after voltage division and filtering, exceeds any preset threshold, the corresponding comparator output will immediately flip from low to high within nanoseconds. The comparator's digital output signal is directly connected to a field-programmable gate array (FPGA). In one embodiment, this FPGA is a Xilinx Artix-7A200T, which is internally configured with a dedicated high-speed interrupt pin and custom fast-response logic. This logic, implemented through a Look-Up Table (LUT) and register array, can immediately generate a trigger signal within 50 nanoseconds (ns) after receiving any comparator output flip signal. The total response delay of the entire instantaneous overvoltage detection circuit from the occurrence of grid voltage anomalies to the FPGA output trigger signal is strictly controlled to within 0.5 milliseconds (ms).

[0063] Secondly, a fast frequency deviation detection circuit. This circuit consists of a high-speed zero-crossing detector and a frequency tracking and comparison unit based on an FPGA-internal digital phase-locked loop (DPLL). The zero-crossing detector uses a high-speed optocoupler, such as the HCNR201 series manufactured by Avago Technologies (now Broadcom). This optocoupler, through precise input current-limiting resistors and output pull-up resistors, accurately converts the AC mains voltage into a square wave signal with jitter less than 50 nanoseconds (ns). The rising and falling edges of this square wave signal are strictly synchronized with the zero-crossing moments of the AC voltage.

[0064] The square wave signal is then input to the DPLL hard core integrated within the FPGA. This hard core, in conjunction with a custom IP core, processes the input signal at an internal sampling frequency of 200MHz. The DPLL module is configured in narrowband mode, featuring a fast lock-on time of less than 2 milliseconds (ms) and enabling high-resolution frequency measurement. The DPLL module continuously tracks the real-time frequency of the power grid and compares it at a high frequency with an internally preset nominal frequency (e.g., 50.00Hz or 60.00Hz). When the instantaneous frequency detected by the DPLL deviates from the nominal frequency by a preset threshold (e.g., ±1.5Hz) for a short time window (e.g., approximately 120 milliseconds over six consecutive grid cycles for a 50Hz grid), the DPLL module generates a frequency anomaly trigger signal. This trigger signal is also directly connected to the fast-response logic within the FPGA.

[0065] Thirdly, the zero-crossing behavior anomaly detection circuit. This circuit shares the same square wave signal output by the zero-crossing detector as the fast frequency deviation detection circuit. The FPGA is internally configured with a high-resolution (1 microsecond) timer to continuously monitor the time interval between consecutive zero-crossing events.

[0066] This submodule uses dedicated logic to determine the following two abnormal situations: when a significantly abnormal time interval between consecutive zero-crossings is detected, for example, exceeding 1.3 times the normal power grid cycle (20 milliseconds for a 50Hz power grid, i.e., exceeding 26 milliseconds), it indicates severe distortion of the power grid waveform or the presence of periodic interruptions; or when no zero-crossing signal is detected for a certain period of time (e.g., 20 milliseconds), it is determined that a power outage or severe waveform interruption may occur. This anomaly detection logic is implemented by an FPGA, which outputs a zero-crossing anomaly trigger signal, with a response delay of less than 1 millisecond (ms) from the occurrence of the anomaly to the signal output.

[0067] All trigger signals generated by the transient anomaly rapid detection submodule, whether from transient overvoltage, rapid frequency deviation, or zero-point crossover anomalies, are converged to one or more dedicated high-speed OR gate arrays within the FPGA. The aggregated output signal of this array is directly used as the direct trip command input to the adaptive isolation module via a low-voltage differential signaling (LVDS) interface with extremely low latency (less than 100 nanoseconds). This hardware-first command path design ensures that in the event of any of the aforementioned severe transient anomalies, the system can initiate physical isolation within a total latency of less than 1 millisecond (including detection and signal transmission), thereby providing ultimate instantaneous protection for portable energy storage power supplies.

[0068] The comprehensive parameter precision detection submodule, working in parallel with the transient anomaly rapid detection submodule, is responsible for high-precision, multi-cycle, steady-state digital acquisition and in-depth analysis of parameters such as grid voltage, current, frequency, and phase. This submodule plays a crucial role in achieving a refined assessment of the steady-state grid condition, and its components include:

[0069] Firstly, high-precision voltage and current sensors. This system employs voltage and current sensors based on the Hall effect principle to provide wide bandwidth, high linearity, and electrical isolation measurement capabilities. In one embodiment, the voltage sensor is a LEMLV25-P type or equivalent, with a rated input voltage of 250VAC, a rated output current of 50mA, linearity better than 0.1%, and a bandwidth greater than 100kHz. This sensor requires a precision attenuation network at the front end to accommodate a wider range of mains voltages. The current sensor is a LEMLA55-P type or equivalent, with a rated input current of 50AAC, a rated output current of 25mA, linearity better than 0.1%, and a bandwidth also greater than 100kHz. These sensors all provide isolated analog output signals proportional to the input voltage / current, ensuring measurement accuracy and system safety isolation.

[0070] Secondly, a multi-channel synchronous analog-to-digital converter (ADC). To achieve high synchronization between voltage and current waveform sampling points for accurate calculation of power factor and phase angle, this system employs a multi-channel, high-resolution, high-sampling-rate synchronous sampling ADC. In a preferred embodiment, the ADS8688A ADC manufactured by Texas Instruments (TI) is selected. This chip has eight independent analog input channels, 16-bit resolution, and a sampling rate of up to 200kSPS (thousands of samples per second) per channel. This ADC incorporates a programmable gain amplifier (PGA), allowing for flexible adjustment of the input range to fully utilize its dynamic range. The ADC accurately converts the isolated analog signals output from the sensors into digital signals.

[0071] Third, the Digital Signal Processor (DSP). The digital output data stream of the ADC is transmitted to a dedicated DSP via a high-speed serial interface (e.g., SPI bus, transmitting data at a rate of 10MHz). In one embodiment, a dual-core DSP, the TMS320F28379D from the TIC2000 series, is used. This chip has a 200MHz clock frequency and integrates a high-performance floating-point unit (FPU), capable of efficiently executing complex real-time digital signal processing algorithms. The firmware embedded in the DSP executes the following real-time algorithms:

[0072] A1. RMS Calculation: A sliding window is used to calculate the RMS value of the voltage and current sampled data from the ADC. This window is typically set to cover at least 5 grid cycles (e.g., 100 milliseconds for a 50Hz grid) to obtain stable and accurate RMS values. The RMS calculation accuracy is designed to be better than 0.5%.

[0073] A2. Precise Frequency and Phase Detection: Employing a frequency estimation algorithm combining zero-point crossover detection and Discrete Fourier Transform (DFT), or an adaptive Kalman filter algorithm, high-precision measurement of the grid frequency at the 0.005Hz level is achieved. Simultaneously, the DSP accurately calculates the phase angle between voltage and current, achieving a measurement accuracy of up to 0.1 degrees, providing a basis for subsequent power factor correction and energy management.

[0074] A3. Harmonic Analysis: By performing a 512-point Fast Fourier Transform (FFT) on the voltage and current waveforms, the harmonic content in the power grid is analyzed and quantified, down to the 50th harmonic. The Total Harmonic Distortion (THD) is calculated based on the analysis results to assess the power grid's power quality. The THD calculation accuracy is better than 0.1%.

[0075] A4. Power Grid Status Assessment: Based on the real-time calculation results above, the DSP rigorously compares key parameters such as the effective value of the power grid voltage, frequency, phase angle, and harmonic distortion rate (THD) with international standards (e.g., IEC61000-4-30 Class A) and the system's internally preset safe operating thresholds. These preset thresholds include, but are not limited to, voltage deviation ±10%, frequency deviation ±0.5Hz, and THD less than 5%. If any parameter exceeds these thresholds, the DSP will generate a detailed power grid status report and transmit it to the central control module via a high-speed CAN bus (1Mbps rate).

[0076] The overall response delay of the comprehensive parameter accurate detection submodule is typically in the range of 10 to 50 milliseconds. Its output detailed grid status data serves as a key basis for the central control module to make decisions, guide the energy management module to dynamically adjust the charging strategy, implement fault diagnosis, record operation logs, and serve as a steady-state decision basis for the adaptive isolation module to de-isolate or safely reconnect to the grid.

[0077] The central control module serves as the intelligent decision-making center for the entire portable energy storage power supply offline grid-connected detection and expansion system, coordinating and managing the operation of all sub-modules. This module includes a high-performance microcontroller (MCU). In a preferred embodiment, an i.MXRT1064 microcontroller manufactured by NXP Semiconductors is used. This chip is based on the ARM Cortex-M7 core, with a clock speed of up to 600MHz, and possesses powerful real-time processing capabilities. The MCU embeds a real-time operating system (RTOS), such as FreeRTOS, to enable multi-tasking concurrent processing and efficient system resource management. Furthermore, the module integrates 4 megabytes (MB) of QSPI Flash non-volatile memory for storing system firmware and critical program code, and 256 kilobytes (KB) of EEPROM for storing system configuration parameters, historical operation logs, and calibration data, ensuring data persistence even after power failure.

[0078] The central control module receives direct trip commands (as the highest priority interrupt) from the transient anomaly rapid detection submodule, as well as detailed grid status data from the comprehensive parameter precise detection submodule. Based on preset control strategies and safety logic, the MCU makes real-time decisions. When it receives a trip command from the transient anomaly rapid detection submodule, the central control module immediately sends a forced isolation command to the adaptive isolation module, records the event log with 1 millisecond (ms) precision, and notifies the energy management module to immediately stop the current charging operation to prevent damage to the battery pack.

[0079] Once the external power grid returns to normal, and the comprehensive parameter precision detection submodule confirms that all key parameters are stable and within safe operating ranges, the central control module will make a decision based on the preset reconnection protocol and a configurable safety delay (e.g., set by the user between 300 and 900 seconds via the human-machine interface module). After the delay, the central control module will issue reconnection commands to the adaptive isolation module in stages. Typically, it will first close the mechanical contactor, wait 500ms for voltage and current synchronization detection, and after confirming no abnormalities, close the high-speed solid-state relay, thereby achieving safe reconnection of the portable energy storage power supply to the grid. In addition, the central control module is also responsible for managing the charging and discharging strategies of the energy management module (e.g., automatically reducing the charging current to 50% of the rated value to protect the battery when grid voltage fluctuations exceed the safe range but do not reach the instantaneous tripping threshold), the power distribution of the extended battery interface module, and the data exchange of the human-machine interface and communication modules. The firmware running on the microcontroller implements complex finite state machine (FSM) control logic to ensure deterministic, stable, and highly reliable system behavior under various grid operating conditions.

[0080] The adaptive isolation module is the key actuator in this invention, enabling rapid and reliable physical isolation between the portable energy storage power supply and the external power grid. Its core design philosophy is a speed-first, stability-later isolation strategy. This module integrates the following three components:

[0081] Firstly, a high-speed solid-state relay (SSR) array. This array consists of multiple sets of AC solid-state relays capable of withstanding high voltage and high current. In a preferred embodiment, a Crydom D53TP25D three-phase solid-state relay is used, with a rated voltage of up to 530VAC and a rated current of 25A. This SSR features zero-point cross-switching characteristics and incorporates an RC buffer circuit to reduce transient overvoltage and current surges during the switching process. Upon receiving a level signal command from the transient anomaly rapid detection submodule, the SSR array can complete the switching action in less than 0.5 milliseconds (ms), achieving instantaneous disconnection from the power grid. To improve system redundancy and thermal management capabilities, two sets of SSRs are typically configured to operate in parallel, with an NTC thermistor connected in series on the heat sink of each SSR to monitor its operating temperature in real time and prevent overheating. The SSR array is the main actuator responding to the direct tripping command issued by the transient anomaly rapid detection submodule.

[0082] Secondly, mechanical contactors. Downstream of the SSR array, one or more high-reliability AC contactors are connected in series to provide long-term, physically disconnected isolation after the SSR operates, and offer higher short-circuit withstand capability. In one embodiment, a Siemens 3RT2026-1BB40 AC contactor is used, with a rated voltage of 230VAC, a rated current of 25A, and a mechanical life greater than 5 million cycles. The mechanical contactor is controlled by a central control module through an independent H-bridge drive circuit with undervoltage trip protection. The operating time of the mechanical contactor is typically between 10 milliseconds (closing) and 15 milliseconds (opening). Mechanical contactors are used to provide lower static power consumption and higher physical isolation security than SSRs during long-term grid outages or when energy storage power sources need to be offline for extended periods.

[0083] Third, the overcurrent protection unit. This unit integrates multiple protection mechanisms to cope with extreme short-circuit faults. It includes ultra-fast fuses with a response time of less than 10 microseconds (μs) (e.g., Littelfuse 0451.250NR, rated current 30A), and / or magnetically tripped circuit breakers (e.g., Schneider Electric C60H, rated current 32A, with an instantaneous trip current set at 5-10 times the rated value). These components provide ultimate overcurrent protection in the event of a severe short-circuit fault, preventing permanent damage to internal system components.

[0084] The adaptive isolation module is designed with ultra-fast transient isolation provided by the SSR array as the primary path, followed by long-term, robust physical isolation provided by mechanical contactors. This hierarchical isolation strategy, prioritizing speed over stability, ensures that the energy storage system can quickly escape danger during any extreme grid transient event, while maintaining absolute physical safety through mechanical contactors in long-term isolation. The module's triggering logic features a hardware-priority interrupt mechanism, meaning that any trip command from the transient anomaly rapid detection submodule bypasses the central control module's conventional decision-making process, directly driving the SSR array to trip within less than 0.5 milliseconds, thereby minimizing response latency.

[0085] The energy management module is responsible for the precise management of the charging and discharging process of the internal battery pack of the portable energy storage power supply, and for efficient energy interaction with external extended battery packs. The core components of this module are as follows:

[0086] Firstly, the Battery Management System (BMS). This system integrates a dedicated battery management IC, such as the TI bq76952 or its equivalent. This BMS supports monitoring of 16 series-connected lithium-ion batteries and integrates a high-precision coulomb counter, analog front-end (AFE), and independent protection functions. It can monitor in real time the individual cell voltage (accuracy ±5mV), total voltage (accuracy ±100mV), charge / discharge current (accuracy ±100mA), battery temperature (accuracy ±1℃), and battery state of health (SOH) and state of charge (SOC) of the internal and extended battery pack. The BMS performs several key protection functions, including but not limited to voltage equalization management, configurable overcharge protection (e.g., 4.25V / cell), over-discharge protection (e.g., 2.75V / cell), overcurrent protection (e.g., 50A charge / discharge current), and over-temperature protection (e.g., 55℃ battery temperature). These protection features precisely control the on / off state of the charge / discharge path by driving an array of N-channel power MOSFETs. In one embodiment, 12 CSD18540Q5B type N-channel power MOSFETs are connected in parallel to achieve low on-resistance (typical Rds(on) 1.2mΩ) and high current carrying capacity.

[0087] Secondly, the AC-to-DC (AC / DC) charger. This charger employs a high-efficiency, power factor correction (PFC) AC / DC conversion topology to convert the AC power input from the grid access module into DC power to charge the battery pack. In a preferred embodiment, an interleaved boost PFC (two-phase) combined with a full-bridge LLC resonant converter topology is used to achieve high efficiency and low harmonic distortion. The PFC stage is designed to achieve a total harmonic distortion (THD) of less than 5% and a power factor greater than 0.98. The overall AC / DC charger's conversion efficiency is targeted to be greater than 95%. This charger has programmable output voltage (40V-60V) and current (0A-20A) capabilities, dynamically adjusted by a central control module based on battery status (SOC, SOH, temperature) and grid quality conditions, and communicated and controlled via PMBus (Power Management Bus).

[0088] Thirdly, the DC-to-AC inverter. This inverter employs a pure sine wave output topology to convert the DC power from the battery pack into AC power to supply external loads. In one embodiment, an H-bridge inverter combined with a sinusoidal pulse width modulation (SPWM) control strategy is used, with real-time control by a high-performance DSP (e.g., sharing a TIC2000 series DSP with the comprehensive parameter precision detection submodule) to ensure the purity of the output AC power. The total harmonic distortion (THD) of the pure sine wave output by the inverter is less than 3%. Its rated output power is 2kW, and it has a peak output capability of up to 4kW (lasting for 10 seconds) to handle instantaneous high-power loads. This inverter integrates multiple protection functions, including overload protection (e.g., 120% rated load for 1 minute), short-circuit transient protection, and over-temperature protection (e.g., automatic shutdown when the internal temperature reaches 85°C).

[0089] The energy management module and the central control module communicate at high speed and reliably via CAN bus or dedicated SPI interface to exchange battery status information and control commands in real time, so as to optimize charging and discharging efficiency and maximize the cycle life and calendar life of the battery system.

[0090] The extended battery interface module is used to safely and reliably connect one or more external extended battery packs, thereby flexibly increasing the total energy capacity of portable energy storage power supplies. The module is designed with safety and compatibility in mind, and its main components include:

[0091] Firstly, the physical connector. It employs high-current, low-contact-resistance industrial-grade waterproof and dustproof connectors, such as the Anderson Powerpole PP75 series or equivalents. This connector is rated for 75A, ensuring a robust electrical connection and low-loss power transfer between the extended battery pack and the main unit. The connector integrates a mechanically foolproof design to effectively prevent incorrect or reverse insertion by the user, thereby avoiding electrical damage.

[0092] Secondly, the communication interface. Dedicated data pins are integrated within the physical connector to establish an isolated CAN bus or UART communication link between the host and the extended battery pack. Through this link, the central control module and energy management module can obtain BMS data from the extended battery pack in real time and securely, including but not limited to key information such as voltage, current, temperature, SOC, and SOH, enabling unified intelligent management of all battery packs.

[0093] Thirdly, the power management and protection circuitry. This module includes a secondary overcurrent protection circuit and a reverse connection protection circuit, independent of the main BMS, to ensure the overall safety of the extended battery pack connection and prevent system damage due to external faults. The secondary overcurrent protection uses a resettable PTC fuse with a rated current of 30A, which automatically recovers after the overcurrent condition is resolved. Reverse connection protection is implemented through a Schottky diode array to minimize losses associated with reverse connection protection. In addition, the interface module also integrates a voltage monitoring circuit on the connector side to verify the voltage compatibility with the host system before connecting the extended battery pack, preventing connection to incompatible or damaged battery packs.

[0094] The design of the extended battery interface module allows users to flexibly expand energy storage capacity according to actual needs without affecting the core detection and isolation functions and safety performance of the main system. Management data for all connected extended battery packs is centrally scheduled and optimized by the central control module.

[0095] The human-computer interaction and communication module provides users with intuitive system status displays, a convenient user input interface, and diverse external data communication functions. This module consists of:

[0096] Firstly, the display unit. A color LCD screen is used; in one embodiment, a 4.3-inch TFT LCD with a resolution of 480x272 pixels is selected. This screen is connected to the central control module via a MIPI interface and is used to display, in real-time and graphically, grid status parameters (e.g., voltage, frequency, THD), battery charging and discharging status (e.g., SOC, SOH, charging and discharging power), remaining power, operating mode (e.g., charging, discharging, off-grid), and any fault alarms or warnings.

[0097] Secondly, the input unit. This unit includes multiple physical buttons with an anti-mistouch design, or a larger 7-inch capacitive touchscreen interface can be selected. Users can use these input methods to switch modes, query parameters, set functions, and confirm faults.

[0098] Thirdly, the wireless communication unit. This module integrates a Wi-Fi module (e.g., based on the ESP32-WROOM-32E module, supporting IEEE 802.11b / g / n standards) and / or a Bluetooth module (e.g., compatible with the Bluetooth Low Energy 5.0 standard) for wireless data exchange, remote monitoring, and online firmware upgrades between the portable energy storage power supply and smartphone applications or cloud platforms. The wireless communication protocol uses MQTToverWi-Fi, combined with TLS encryption, to ensure the security of data transmission.

[0099] Fourth, the wired communication unit. This module includes a USB Type-C interface that supports the USB Power Delivery (PD) 3.0 protocol. It can be used for charging the portable power storage device itself, and also serves as an interface for local data transmission, system diagnostics, and firmware programming (supporting USB 2.0 data rates). Simultaneously, an Ethernet interface can be integrated to provide a more stable and faster local network connection in specific application scenarios.

[0100] The human-computer interaction and communication module exchanges data with the central control module through standard communication protocols (e.g., Modbus TCP / IP over Ethernet or MQTT over Wi-Fi) to ensure the accuracy and real-time nature of information, and improve user experience and system manageability.

[0101] The specific workflow of the portable energy storage power supply offline grid-connected detection and expansion system provided by this invention is as follows:

[0102] When the portable energy storage power supply is connected to the external AC power grid via the grid access module, the multi-rate grid status detection module immediately activates its parallel detection mechanism. The transient anomaly rapid detection submodule continuously monitors the instantaneous amplitude of the grid voltage, severe frequency fluctuations, and zero-point crossing behavior with a sub-millisecond response speed. If the transient overvoltage detection circuit detects that the grid voltage peak exceeds the preset 300V AC effective value (approximately 424V peak value) threshold, or the rapid frequency deviation detection circuit detects a frequency deviation from the nominal value (e.g., 50Hz) exceeding ±1.5Hz within six consecutive grid cycles, or the zero-point crossing behavior anomaly detection circuit detects an abnormal consecutive zero-point crossing time interval (e.g., exceeding 26 milliseconds) or the zero-point signal disappears within 20 milliseconds, this submodule will immediately generate a direct trip command. This command bypasses the conventional decision-making process of the central control module and directly triggers the high-speed solid-state relay array in the adaptive isolation module via a dedicated LVDS path. This SSR array can complete the disconnection action within 300 microseconds after receiving the command, thereby rapidly disconnecting the portable energy storage power supply from the external power grid within a total time of less than 1 millisecond (including detection and isolation). This rapid isolation mechanism effectively prevents overvoltage damage to the internal and extended battery packs caused by instantaneous power grid surges, and completely eliminates the safety hazard of islanding. Simultaneously, the trip command will notify the central control module as a high-priority interrupt. The central control module will then record a detailed event log and instruct the mechanical contactor in the adaptive isolation module to physically disconnect within 10 milliseconds after the SSR actuation, providing long-term power outage isolation protection.

[0103] Meanwhile, the comprehensive parameter precision detection submodule continuously performs high-precision measurement and in-depth analysis of parameters such as the RMS voltage, RMS current, precise frequency, phase angle, and harmonic distortion rate of the power grid with a response period of 10 to 50 milliseconds. The DSP generates a detailed power grid status report based on this data and transmits it to the central control module via the CAN bus. The central control module uses this detailed data to assess the overall stability and power quality of the power grid and dynamically adjusts the charging strategy of the energy management module accordingly. For example, when the comprehensive parameter precision detection submodule reports that the RMS voltage fluctuation exceeds the set safety range (e.g., ±5%) but does not reach the instantaneous tripping threshold, the central control module will instruct the AC / DC charger of the energy management module to automatically reduce the charging current to 50% of the rated value to protect the battery system from continuous minor power grid fluctuations, thereby extending battery life.

[0104] When a power outage occurs and the adaptive isolation module quickly trips, the central control module continuously monitors the grid status from the comprehensive parameter precision detection submodule. Once it is confirmed that the grid has fully stabilized and all parameters (including voltage, frequency, THD, etc.) are within safe operating ranges, the central control module follows a preset reconnection protocol. This protocol typically includes a configurable safety delay period (e.g., set between 300 and 900 seconds) to ensure long-term grid stability and prevent fluctuations after a brief recovery. After the delay, the central control module instructs the AC / DC charger of the energy management module to enter pre-charging mode and, through the mechanical contactor and high-speed solid-state relay array in the adaptive isolation module, reconnects the portable energy storage power supply to the grid in a phased and controlled manner, restoring its normal charging function. Specifically, the mechanical contactor is first closed, and the central control module waits another 500ms. During this time, the DSP synchronously detects the phase and amplitude of the grid voltage and the system's internal voltage to ensure good synchronization before closing the high-speed solid-state relay to complete the grid connection operation.

[0105] The technical effects of the present invention will be further illustrated below through a specific embodiment and comparative example.

[0106] Example 1: Verification of instantaneous overvoltage tripping

[0107] This embodiment aims to verify the response speed and protection effect of the system of the present invention in dealing with instantaneous overvoltage events in the power grid.

[0108] Test scenario setup: The portable energy storage power supply is connected to a simulated power grid, which is initially stable at 220V AC RMS, 50Hz. The system is in normal charging mode, with the battery pack voltage at 50VDC. At any instant after the start of the test, the simulated power grid voltage is set to rise from 220VRMS to 300VRMS within 100 microseconds, maintain this peak voltage for 500 microseconds, and then return to normal.

[0109] The response of the system (embodiment) of the present invention:

[0110] When the simulated grid voltage instantaneously rises to 300 VRMS, its peak voltage is approximately 424V. The instantaneous overvoltage detection circuit in the transient anomaly fast detection submodule of this invention is configured to trigger when the voltage peak reaches 380V (corresponding to approximately 270 VRMS). In this test, the comparator array outputs a toggle signal within approximately 100 microseconds after the voltage reaches the 380V peak. The fast response logic inside the FPGA generates a trip instruction within 50 microseconds of receiving this signal. This instruction is directly transmitted to the adaptive isolation module via LVDS. The high-speed solid-state relay (SSR) array in the adaptive isolation module completes the disconnection action within 300 microseconds of receiving the instruction.

[0111] Results: The total response time from the occurrence of a transient overvoltage in the power grid to the completion of physical isolation by the system was 100μs (detection) + 50μs (FPGA logic) + 300μs (SSR action) = 450 microseconds (i.e., 0.45 milliseconds). Within this extremely short 0.45 milliseconds, the portable energy storage power supply and its battery pack were disconnected from the external power grid. Therefore, the internal voltage of the battery pack did not significantly exceed the safety limit, nor was it subjected to an overvoltage surge. The system then entered offline mode and logged the event.

[0112] The response of the traditional system (comparative):

[0113] A typical traditional portable energy storage system relies on a microcontroller (MCU) for analog-to-digital converter (ADC) sampling and software-based judgment for grid monitoring. Assuming an ADC sampling rate of approximately 10kHz and a grid status judgment cycle of 10 milliseconds, under the same test scenario, when the grid voltage momentarily spikes, the traditional system must wait until the end of the next 10-millisecond judgment cycle to detect the voltage anomaly. Assuming the isolation action is performed by a mechanical relay or contactor, its action time is typically 10 to 15 milliseconds.

[0114] Results: The total response time from the occurrence of a transient overvoltage in the power grid to the completion of physical isolation by the system is approximately 10.0 ms (detection delay) + 15.0 ms (relay action) = 25.0 milliseconds. During this 25.0 millisecond period, the battery pack of the portable energy storage power supply will be continuously exposed to a transient overvoltage environment of 300 VRMS. According to battery performance test data, long-term or repeated exposure of lithium-ion batteries to voltages exceeding their rated safety thresholds will lead to irreversible degradation of the internal electrochemical materials of the battery, such as the collapse of the positive electrode material structure, electrolyte decomposition, and accelerated lithium plating on the negative electrode, thereby significantly shortening the battery's cycle life and calendar life. Simulation tests show that compared to batteries that have not been subjected to overvoltage shocks, batteries subjected to a 25-millisecond overvoltage shock may experience an additional 5% to 10% increase in capacity decay after 500 cycles.

[0115] By comparing the above embodiments with comparative examples, the system of the present invention demonstrates significant superiority in response speed to transient anomalies in the power grid, reducing the response time by approximately 55 times, thereby effectively protecting the battery system and extending its service life.

[0116]

[0117]

[0118] This invention decomposes grid state detection into two complementary layers: one focusing on hardware acceleration and ultra-fast response pathways for extreme transient events, and the other focusing on precise software analysis pathways for comprehensive steady-state parameters. This layered processing architecture completely resolves the inherent contradiction between response speed and detection accuracy in existing single-detection systems. The system's layered, multi-rate detection architecture, combined with a hardware-priority tripping mechanism and a fast-then-stable adaptive isolation strategy, enables the system to have higher safety redundancy and operational reliability under extreme conditions. Simultaneously, by expanding the battery interface module, the system can flexibly and safely connect additional battery capacity to meet the energy needs of different users, while the core detection and isolation functions remain unaffected, further enhancing the overall product value and market competitiveness of the portable energy storage power supply.

[0119] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A portable energy storage power supply offline grid-connected detection and expansion system, characterized in that, The system includes: a power grid access module, a multi-rate power grid status detection module, a central control module, an adaptive isolation module, an energy management module, an extended battery interface module, and a human-machine interaction and communication module. The multi-rate power grid state detection module is used to simultaneously provide ultra-fast response to power grid transient anomalies and accurate monitoring of power grid steady-state parameters, including a transient anomaly rapid detection submodule and a comprehensive parameter accurate detection submodule; The adaptive isolation module is directly associated with the transient anomaly rapid detection submodule and is used to achieve physical isolation between the portable energy storage power supply and the external AC power grid within milliseconds when a transient anomaly in the power grid is detected. The central control module is used to receive high-priority tripping commands from the transient anomaly rapid detection submodule and detailed grid status data from the comprehensive parameter accurate detection submodule, and make decisions based on preset control strategies and safety logic, coordinate the energy management module to adjust charging and discharging strategies, and control the adaptive isolation module to perform off-grid or reconnection operations. The energy management module is used to manage the charging and discharging process of the internal battery pack of the portable energy storage power supply, and to interact with the external extended battery pack connected to the extended battery interface module. The extended battery interface module is used to connect one or more external extended battery packs to increase the total energy capacity of the portable energy storage power supply. The human-computer interaction and communication module is used to provide system status display, user input, and external data communication functions; The above modules are interconnected through a high-speed data bus and dedicated control signal lines, and work together to achieve rapid offline grid connection detection and safe isolation of the power grid; All trigger signals generated by the transient anomaly rapid detection submodule are aggregated into a dedicated high-speed OR gate array inside the programmable gate array. The aggregated output signal of the gate array is used as the direct tripping command input of the adaptive isolation module through a low-voltage differential signal interface. Once the external power grid returns to normal and the comprehensive parameter precision detection submodule confirms that the key parameters are stable and within the safe operating range, the central control module will make a decision based on the preset reconnection protocol and configurable safety delay. After the safety delay ends, it will issue reconnection commands to the adaptive isolation module in stages. First, it will control the closing of the mechanical contactor. After confirming that there are no abnormalities through voltage and current synchronization detection, it will then control the closing of the high-speed solid-state relay to achieve safe reconnection of the portable energy storage power supply to the power grid.

2. The portable energy storage power supply offline grid-connected detection and expansion system according to claim 1, characterized in that, The multi-rate power grid status detection module includes: The transient anomaly rapid detection submodule is used to detect rapid changes in grid voltage, drastic fluctuations in frequency, and zero-point crossing anomalies within a sub-millisecond time, and generate a direct trip command. The comprehensive parameter precision detection submodule generates a detailed power grid status report.

3. The portable energy storage power supply offline grid-connected detection and expansion system according to claim 2, characterized in that, The transient anomaly rapid detection submodule includes a transient overvoltage detection circuit, which includes: An analog comparator array whose input is connected to the mains voltage signal after passing through a precision voltage divider network and filter circuit; The precision voltage divider network, composed of a series resistor array and a parallel sampling capacitor network, attenuates the high-voltage AC signal proportionally to the input range acceptable to the comparator. The filter circuit is used to remove high-frequency noise and retain transient voltage change information; The comparator's digital output signal is directly connected to a field-programmable gate array (FPGA), which generates a trigger signal within 50 nanoseconds after receiving a toggle signal from any comparator output.

4. The portable energy storage power supply offline grid-connected detection and expansion system according to claim 1, characterized in that, The transient anomaly rapid detection submodule includes a rapid frequency deviation detection circuit, which includes: At least one high-speed zero-crossing detector is used to accurately convert AC grid voltage into a square wave signal, the rising and falling edges of which are strictly synchronized with the zero-crossing time of the AC voltage. At least one frequency tracking and comparison unit based on a digital phase-locked loop (PLL) is provided. The PLL module is integrated inside the programmable gate array (PGA) and performs a high-frequency comparison with the internally preset nominal frequency.

5. A portable energy storage power supply offline grid-connected detection and expansion system according to claim 4, characterized in that, The transient anomaly rapid detection submodule includes a zero-point crossover behavior anomaly detection circuit, which shares the square wave signal output by the zero-point crossover detector with the rapid frequency deviation detection circuit. The programmable gate array is internally configured with a high-resolution timer to continuously monitor the time interval between consecutive zero-point crossover events and determine one of the following two abnormal conditions: Anomaly 1: The time interval between consecutive zero-point crossovers is detected to exceed 1.3 times the normal power grid cycle; Anomaly 2: No zero-crossing signal was detected within 20 milliseconds; The programmable gate array implements the anomaly detection logic, which outputs a zero-point crossover anomaly trigger signal.

6. The portable energy storage power supply offline grid-connected detection and expansion system according to claim 1, characterized in that, The comprehensive parameter accurate detection submodule includes: A high-precision voltage and current sensor is used to acquire the voltage and current waveforms of the power grid in real time. The sensor provides an isolated analog output signal that is proportional to the input voltage / current. A multi-channel synchronous analog-to-digital converter is used to convert the analog signal output by the sensor into a digital signal; A dedicated digital signal processor is provided, wherein the digital output data stream of the multi-channel synchronous analog-to-digital converter is transmitted to the dedicated digital signal processor via a high-speed serial interface.

7. A portable energy storage power supply offline grid-connected detection and expansion system according to claim 6, characterized in that, The firmware embedded in the digital signal processor executes the following real-time algorithm: A1. RMS Value Calculation: Perform sliding window RMS value calculation on voltage and current sampling data from multiple power grid cycles; A2. Precise Frequency and Phase Detection: Zero-point crossover detection combined with a frequency estimation algorithm based on discrete Fourier transform or an adaptive Kalman filter algorithm is used to measure the power grid frequency and accurately determine the phase angle between voltage and current. A3. Harmonic Analysis: The harmonic content in the power grid is analyzed and quantified by performing fast Fourier transform on the voltage and current waveforms. A4. Power Grid Status Assessment: Used to generate power grid status reports; The detailed power grid status data output by the comprehensive parameter precision detection submodule is transmitted to the central control module via a high-speed data bus.

8. The portable energy storage power supply offline grid-connected detection and expansion system according to claim 1, characterized in that, The adaptive isolation module includes a high-speed solid-state relay array, which comprises multiple sets of AC solid-state relays that are resistant to high voltage and high current.

9. A portable energy storage power supply offline grid-connected detection and expansion system according to claim 8, characterized in that, The adaptive isolation module also includes: A mechanical contactor, in series with one or more high-reliability AC contactors downstream of the high-speed solid-state relay array, the mechanical contactor being controlled by the central control module via an independent drive circuit; Overcurrent protection unit, integrating high-speed fuse and / or magnetic trip circuit breaker.

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