Power configuration and control system of low-voltage flexible interconnection device based on battery SOH

Abstract

The invention provides a battery SOH-based power configuration and control system of a low-voltage flexible interconnection device, which comprises an EMS, an energy storage battery, a bidirectional converter, a bus and a BMS, and is characterized in that the energy storage battery is electrically connected with the bus through the bidirectional converter, and the EMS communicates with the BMS and the bidirectional converter to obtain an operation state and parameters of the energy storage battery; the BMS comprises a data acquisition module for acquiring battery operation parameters and data in real time and an SOH calculation and evaluation module for calculating the SOH value of the battery based on the real-time data of the data acquisition module, and the EMS comprises a power configuration module for configuring the SOH value of the battery based on the SOH value calculated by the BMS according to the priority of energy storage scheduling and a set power limit value; the dispatching instruction is generated on the premise of meeting the voltage constraint of the power distribution network, overload of the low-health-degree battery can be effectively avoided, the energy storage life is prolonged, and the economical efficiency, reliability and safety of micro-grid operation are improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic-storage integrated systems, and in particular to a power configuration and control system for low-voltage flexible interconnect devices based on battery SOH. Background Technology

[0002] In recent years, with the rapid development of microgrid systems, the deployment of battery energy storage systems in the power grid has been increasing, becoming a key component for improving the reliability and profitability of microgrids. As batteries are constantly being charged and discharged, their capacity and working ability will gradually degrade over time, thereby reducing their dispatching capabilities to support the operation of microgrids.

[0003] Therefore, effective and accurate monitoring of battery state of health (SOH) provides important data for predicting lifespan and making maintenance, repair or replacement decisions, which is crucial for reducing capital costs, achieving optimal microgrid operation and ensuring optimal battery performance. Summary of the Invention

[0004] This invention provides a power configuration and control system for a low-voltage flexible interconnect device based on battery state of health (SOH). It effectively and accurately monitors the health status of the battery, provides scheduling priority and charging / discharging power according to the health status, and provides constraints such as feeder voltage, thereby achieving the sustainability and economy of energy storage battery use.

[0005] To achieve the above objectives, this technical solution provides: an EMS, an energy storage battery, a bidirectional converter, a bus, and a BMS. The energy storage battery is electrically connected to the bus via the bidirectional converter. The EMS communicates with the BMS and the bidirectional converter to obtain the operating status and parameters of the energy storage battery. The BMS includes: a data acquisition module and a SOH calculation and evaluation module. The data acquisition module is used to collect battery operating parameters and data in real time, and the SOH calculation and evaluation module calculates the SOH value of the battery based on the real-time data from the data acquisition module. The EMS includes: a power configuration module, which issues scheduling commands for the microgrid system based on the SOH value from the SOH calculation and evaluation module.

[0006] Furthermore, the data acquisition module is used to collect the battery's temperature, current, and voltage.

[0007] Furthermore, in the SOH calculation and evaluation module, the SOH calculation formula is used:

[0008]

[0009] in, It is the initial SOH. The SOH decreases at each time step. It represents the instantaneous battery charge and discharge rate, which is the ratio of the battery charge and discharge current to the rated capacity. N is the number of round-trip cycles calculated before the end of the battery life, N is the factor for the reduction of the remaining capacity, and T is the temperature.

[0010] Furthermore, the EMS provides an energy scheduling priority strategy: When SOH > 0.9, the energy storage battery preferentially undertakes the tasks of peak shaving and valley filling, and rapid frequency modulation; When 0.75 < SOH ≤ 0.9, the energy storage participates in the intra-day energy transfer; When SOH ≤ 0.75, it is only used as emergency backup, and active scheduling is prohibited; The EMS also provides the power limit conditions for energy storage scheduling, and establishes the mapping relationship between the charge and discharge power and SOH, SOC in the power configuration module:

[0011] is the maximum available power at time, and the power scheduling issued by the EMS should not be greater than the maximum available power. is the rated power, is the health state, is the battery temperature, is the state of charge, is a constant, usually .

[0012] Furthermore, in the EMS, the voltage constraint condition of the distribution network is also established as:

[0013] is the allowable voltage lower limit, is the allowable voltage upper limit, is the voltage amplitude of node in the distribution network.

[0014] The beneficial effects of the present invention are: The BMS collects the battery operation data in real time through the data acquisition module and calculates the health state (SOH). The EMS generates the scheduling instructions according to the priority of energy storage scheduling, the set power limit, and on the premise of meeting the voltage constraint of the distribution network, which can effectively avoid overloading of low-health batteries, extend the energy storage life, and improve the economy, reliability and safety of the microgrid operation. Specific implementation manners

[0015] This technical solution provides: an EMS, an energy storage battery, a bidirectional converter, a bus, and a BMS. The energy storage battery is electrically connected to the bus through the bidirectional converter. The EMS communicates with the BMS and the bidirectional converter to obtain the operation state and parameters of the energy storage battery.

[0016] The BMS includes: a data acquisition module and a SOH calculation and evaluation module. The data acquisition module is used to collect battery operation parameters and data in real time, including the temperature, current, and voltage of the battery. The SOH calculation and evaluation module calculates the SOH value of the battery based on the real-time data of the data acquisition module, and the formula used is:

[0017]

[0018] Where, is the initial SOH, is the SOH reduction at each time, represents the instantaneous battery charge-discharge rate, which is the ratio of the charge-discharge current of the battery to the rated capacity. N is the number of round-trip cycles calculated before the end of the battery life, N is the factor for the reduction of the remaining capacity, and T is the temperature.

[0019] The EMS includes: a power configuration module. The power configuration module issues scheduling instructions for the microgrid system based on the SOH value of the SOH calculation and evaluation module. More precisely, it generates scheduling conditions adapted to the current SOH value according to the set energy scheduling priority strategy. Through SOH hierarchical scheduling, it avoids high-stress conditions for deteriorated batteries: First, determine the energy scheduling priority strategy as: When SOH > 0.9, the energy storage battery preferentially undertakes peak shaving and valley filling, and fast frequency modulation tasks; When 0.75 < SOH ≤ 0.9, the energy storage participates in intraday energy transfer; When SOH ≤ 0.75, it is only used as emergency backup, and active scheduling is prohibited.

[0020] The EMS also provides power limit conditions for energy storage scheduling, and establishes a mapping relationship between charge-discharge power and SOH, SOC in the power configuration module:

[0021] is the maximum available power at time, and the power scheduling issued by the EMS should not be greater than the maximum available power. is the rated power, is the health state, is the battery temperature, is the state of charge, is a constant, usually and its value decreases as the SOH decreases, the temperature deviates, or the SOC approaches the boundary; The scheduling power instruction that the EMS can issue is: The scheduling power instruction is always within the current maximum capacity of the battery, and the execution success rate is high.

[0022] Furthermore, voltage constraints are established in the EMS to ensure that the power quality on the user side meets the specifications. The voltage constraints are as follows:

[0023] The lower limit of the allowable voltage. The upper limit of the permissible voltage, For nodes in the distribution network The voltage amplitude.

[0024] In addition to the embodiments described above, the present invention may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A power configuration and control system for a low-voltage flexible interconnect device based on battery state of equilibrium (SOH), comprising: The system comprises an EMS (Energy Management System), an energy storage battery, a bidirectional converter, a bus, and a BMS (Battery Management System). The energy storage battery is electrically connected to the bus via the bidirectional converter. The EMS communicates with the BMS and the bidirectional converter to obtain the operating status and parameters of the energy storage battery. The BMS includes a data acquisition module and a State of Health (SOH) calculation and evaluation module. The data acquisition module collects battery operating parameters and data in real time, and the SOH calculation and evaluation module calculates the SOH value of the battery based on the real-time data from the data acquisition module. The EMS includes a power configuration module, which issues scheduling commands for the microgrid system based on the SOH value calculated by the SOH calculation and evaluation module.

2. The power configuration and control system for the low-voltage flexible interconnect device based on battery SOH according to claim 1, characterized in that: The data acquisition module is used to collect the battery's temperature, current, and voltage.

3. The power configuration and control system for the low-voltage flexible interconnect device based on battery SOH according to claim 2, characterized in that: In the SOH calculation and evaluation module, the SOH is calculated using the following formula: in, It is the initial SOH. The SOH decreases at each time step. This represents the instantaneous battery charge / discharge rate, the ratio of the battery's charge / discharge current to its rated capacity, N is the number of round trip cycles calculated before the end of the battery's life, N is the factor for the reduction of remaining capacity, and T is the temperature.

4. The power configuration and control system for the low-voltage flexible interconnect device based on battery SOH according to claim 3, characterized in that: The EMS provides an energy scheduling priority strategy: when SOH > 0.9, the energy storage battery preferentially undertakes the tasks of peak shaving and valley filling, and rapid frequency modulation; when 0.75 < SOH ≤ 0.9, the energy storage participates in intraday energy transfer; when SOH ≤ 0.75, it is only used as emergency backup and active scheduling is prohibited. The EMS also provides the power limit conditions for energy storage scheduling, and establishes the mapping relationship between charge-discharge power and SOH, SOC in the power configuration module: is the maximum available power at the moment, and the power scheduling issued by the EMS should not be greater than the maximum available power. is the rated power, is the health state, is the battery temperature, is the state of charge, is a constant, usually .

5. The power configuration and control system for the low-voltage flexible interconnect device based on battery SOH according to claim 4, characterized in that: In EMS, the distribution network voltage constraint conditions are also established as follows: The lower limit of the allowable voltage. The upper limit of the permissible voltage, For nodes in the distribution network The voltage amplitude.

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