AC monitoring method and system based on battery electronic module

Abstract

The invention discloses an AC monitoring method and a system based on a battery electronic module. The system comprises a harmonic detection module, a single battery inner resistance calculation module, a data processing module and a harmonic injection module, wherein the harmonic detection module is used for detecting a harmonic signal in the battery electronic module, the frequency of the harmonic signal is m times that of the power grid, and m is an integer larger than 1; the single battery inner resistance calculation module is used for calculating the single battery inner resistance according to the detected harmonic signal and a single battery model; the data processing module is used for calculating the state of charge of the single battery according to the detected harmonic signal and the single battery inner resistance; and the harmonic injection module is used for outputting a harmonic signal for controlling the battery electronic module to complete conversion between DC and AC according to an instruction of the data processing module. The battery performance measurement cost can be reduced, the battery performance measurement precision is improved and the battery-side quick measurement is realized.

Description

technical field [0001] The invention relates to the field of energy, in particular to an AC monitoring method and system based on a battery electronic module. Background technique [0002] At present, how to store electric energy in the grid has always been an important problem to be solved in the energy field. In order to solve this problem to a certain extent, DC / AC single-stage or DC / DC+DC / AC two-stage bidirectional power converters are used in the prior art to realize bidirectional power flow between the battery and the grid. [0003] Since the current energy storage system uses multiple batteries connected in series to form a high-voltage DC battery pack, once any battery unit in the battery pack is damaged, the entire energy storage system will not work properly, which is not suitable for safe power supply. occasions, such as coal mines, oil fields and other industrial occasions. [0004] The Chinese patent document "A Modularized Medium-voltage Energy Storage System...

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Problems solved by technology

[0003] Since the current energy storage system uses multiple batteries connected in series to form a high-voltage DC battery pack, once any battery unit in the battery pack is damaged, the entire energy storage system will not work properly, which is not suitable for safe power supply. occasions, such as coal mines, oil fields and other industrial occasions

[0004] The Chinese patent document "A Modularized Medium-voltage Energy Storage System" (publication number CN102355065) provides a way to realize energy storage. The primary side adopts a star connection, and realizes charging, discharging, and equalization by controlling the three phase voltages. However, the energy storage system needs to properly control the amplitude and phase of the three-phase voltage when performing phase-to-phase balance and fault redundancy control. Due to the mutual coupling of the control of the three-phase voltage, the control is difficult, which is not conducive to its stability. run

[0005] The Chinese patent document "A Large-Capacity Medium-Voltage Battery Energy Storage System" (publication number CN103199630A) provides another way to realize energy storage. The battery module still uses a high-voltage module, and it has to withstand twice the power that the system itself cannot overcome. Frequency power pulsation will have a certain impact on battery life and normal use, and the connection mode of direct connection on the AC side will make the fault design of the system more complicated, and will also generate common mode interference, which is not conducive to the normal operation of the management and control system

The state of charge SOC is related to the battery model. Aging or process may make the parameters of the battery model different. In order to dynamically update the SOC, a complete battery discharge process needs to be performed, which is inconvenient to monitor battery performance.

[0008] Finally, in order to enable the energy storage system to be applied to different power generation, transmission, and distribution occasions, to play the role of peak shaving and valley filling, improving new energy grid connection capabilities, island operation, grid frequency regulation, and backup power, it is necessary to provide energy storage systems with control, and the existing energy storage system is composed of battery management system (BMS) and power conversion system (PCS) divided into two modules, and upload information to the main controller respectively, poor integration, high cost, so it is necessary Propose a low-cost, high-efficiency energy storage system control technology solution

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