A method for controlling power-up of an energy storage battery system

Abstract

The application provides a power-on control method for an energy storage battery system, which comprises the following steps: S1, low-voltage power-on of the energy storage battery system; S2, self-checking of the energy storage battery system, judgment of whether there is an abnormality, if there is an abnormality, power-on is stopped and protection is performed, if there is no abnormality, the next power-on process is entered; S3, judgment of whether the energy storage battery system is in a grid-connected state, if the energy storage battery system is in the grid-connected state, an AC-to-DC pre-charging working mode of an energy storage converter is performed, AC power is converted into DC power through a rectification and transformation circuit, and the system bus voltage is pre-charged to meet the voltage of the battery system within a set time. The power-on control method for the energy storage battery system can replace the original pre-charging circuit system scheme, thereby reducing the cost, and can ensure that the energy storage converter works in a safe condition, and is more reliable than the original system scheme.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of energy storage battery, in particular to a power-on control method of an energy storage battery system. BACKGROUND

[0002] In the existing energy storage system BMS, a traditional busbar series resistor pre-charging circuit scheme is adopted to avoid excessive voltage difference between the two sides of the switch during power-on, excessive current generated at the moment of closing, damage to the main control switch in the battery pack, protection of the busbar main control switch by the pre-charging circuit, and provision of reliable stability for the battery pack power-on process.

[0003] In order to achieve the above purpose, other ways can also be developed to replace the pre-charging circuit scheme and reduce costs. SUMMARY

[0004] The purpose of the present application is to propose a power-on control method of an energy storage battery system to replace the traditional power-on scheme of the energy storage battery system using a pre-charging circuit and to reduce costs to some extent.

[0005] The technical scheme of the present application is as follows:

[0006] A power-on control method of an energy storage battery system, comprising the following steps:

[0007] S1, low-voltage power-on of the energy storage battery system;

[0008] S2, self-checking of the energy storage battery system to determine whether there is an abnormality, if there is an abnormality, the power-on is stopped and protection is performed, if there is no abnormality, the next power-on process is entered;

[0009] S3, determination of whether the energy storage battery system is in a grid-connected state, if the energy storage battery system is in a grid-connected state, the energy storage converter performs an AC-to-DC pre-charging working mode, converts AC power into DC power through a rectifier and transformer circuit, and pre-charges the system busbar voltage to meet the battery system voltage within a set time;

[0010] S4, detection of the voltage of the battery pack and the voltage of the battery pack output end by the battery management unit, and feedback of the voltage state to the energy storage converter through communication;

[0011] S5, during the execution of the above pre-charging, the battery management system monitors the busbar voltage state to determine whether the pre-charging voltage meets the condition of closing the main control switch within a specified time, if yes, the pre-charging is successful, the main control switch is closed, and the system DC busbar power-on is completed, otherwise, the pre-charging is timed out, the pre-charging fails, the power-on is cancelled, and the fault is recorded;

[0012] S6, connecting the above process step S3, if the energy storage battery system is not in the grid-connected state, it is in the off-grid state, it is necessary to judge whether the photovoltaic input is stable, if it is not stable, it waits and then executes the pre-charge of a new round; if the photovoltaic input is stable, the energy storage converter executes the pre-charge working mode of direct current to direct current, and converts the photovoltaic input voltage into the bus voltage through the buck-boost circuit; the photovoltaic input voltage is higher than the battery voltage, and the buck-boost circuit executes the buck mode, and the photovoltaic input voltage is lower than the battery voltage, and the buck-boost circuit executes the boost mode.

[0013] The beneficial effects of the present application: after the system of the present application is powered on, the energy storage converter first detects the voltage state of the direct current bus side, the battery pack detects the battery end, the photovoltaic cell state and the voltage state of the battery pack output end (the direct current bus side), according to the voltage state in the battery pack and the direct current bus voltage state, the energy storage converter increases the direct current bus side voltage to be basically consistent with the battery pack through the rectification working mode, realizes the pre-charge process, replaces the original pre-charge circuit, thereby reducing the cost, and can also ensure that the energy storage converter works in a safe condition, and compared with the original system scheme, it is more reliable. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, without creative labor, other drawings can also be obtained according to these drawings.

[0015] Figure 1 The flow chart of the present application;

[0016] Figure 2 The circuit connection diagram. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of the present application.

[0018] Reference Figure 1 A power-on control method of an energy storage battery system, comprising the following steps:

[0019] S1, the energy storage battery system is powered on at low voltage;

[0020] S2, the energy storage battery system performs self-checking to determine whether there is an abnormality, if there is an abnormality, the power-on is stopped and protection is performed, if there is no abnormality, the next power-on process is entered;

[0021] S3, it is determined whether the energy storage battery system is in a grid-connected state, if the energy storage battery system is in the grid-connected state, the energy storage converter performs an AC-to-DC pre-charging working mode, converts AC into DC through a rectification and voltage conversion circuit, and pre-charges the system bus voltage to meet the battery system voltage within a set time;

[0022] S4, the battery management unit detects the voltage of the battery pack and the voltage of the battery pack output end, and feeds back the voltage state to the energy storage converter through communication;

[0023] S5, in the process of performing the above pre-charging, the battery management system monitors the bus voltage state, determines whether the pre-charging voltage within a specified time meets the condition of closing the main control switch, if yes, the pre-charging is successful, the main control switch is closed, and the system DC bus power-on is completed, otherwise, the pre-charging is timed out, the pre-charging fails, the power-on is cancelled, and the fault is recorded;

[0024] S6, as described in the above process step S3, if the energy storage battery system is not in the grid-connected state, it is in an off-grid state, it is necessary to determine whether the photovoltaic input is stable, if not, it is waited for and a new round of pre-charging is performed, if the photovoltaic input is stable, the energy storage converter performs a DC-to-DC pre-charging working mode, converts the photovoltaic input voltage into the bus voltage through a buck-boost circuit, if the photovoltaic input voltage is higher than the battery voltage, the buck-boost circuit performs a buck mode, and if the photovoltaic input voltage is lower than the battery voltage, the buck-boost circuit performs a boost mode.

[0025] The circuit connection block diagram is as follows Figure 2 .

[0026] After the system power-on trigger of the present application, firstly, the energy storage converter detects the DC bus voltage state, the battery pack detects the battery end, the photovoltaic cell state and the voltage state of the battery pack output end (DC bus side), according to the voltage state in the battery pack and the DC bus voltage state, the energy storage converter increases the DC bus voltage to be basically consistent with the voltage of the battery pack through the rectification working mode, realizes the pre-charging process, replaces the original pre-charging circuit, thereby reducing the cost, and can ensure that the energy storage converter works in a safe condition, and compared with the original system scheme, is more reliable.

[0027] The above only describes the preferred embodiments of the present application and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for controlling power-on of an energy storage battery system, characterized in that: The following steps are involved: S1, energy storage battery system low voltage power on; S2: The energy storage battery system performs a self-check to determine whether there is any abnormality. If there is an abnormality, the power-on is terminated and protection is executed; if there is no abnormality, the system enters the next power-on process; S3. Determine whether the energy storage battery system is in a grid-connected state. If the energy storage battery system is in a grid-connected state, the energy storage converter performs an AC-to-DC pre-charge operation mode, converts AC power into DC power through a rectifier and transformer circuit, and pre-charges the system bus voltage to meet the battery system voltage within a set time. S4. The battery management unit detects the voltage of the battery pack and the voltage of the battery pack output terminal, and feeds back the voltage status to the energy storage converter through communication; S5. During the pre-charging process, the battery management system monitors the bus voltage status and determines whether the pre-charging voltage meets the conditions for closing the main control switch within the specified time. If so, the pre-charging is successful, the main switch is closed, and the system DC bus is powered on. Otherwise, the pre-charging times out, the pre-charging fails, the power-on is canceled, and the fault is recorded. S6, go to process step S3. If the energy storage battery system is not in the grid-connected state, it is in the off-grid state. It is necessary to first determine whether the photovoltaic input is stable. If it is unstable, wait and then perform a new round of pre-charging. If the photovoltaic input is stable, the energy storage converter performs the DC-DC pre-charging working mode, and converts the photovoltaic input power into the bus voltage through the buck-boost circuit. If the photovoltaic input voltage is higher than the battery voltage, the buck-boost circuit performs the buck mode. If the photovoltaic input voltage is lower than the battery voltage, the buck-boost circuit performs the boost mode.

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