CN-122026586-A - Charging system and charging method of flow battery

CN122026586ACN 122026586 ACN122026586 ACN 122026586ACN-122026586-A

Abstract

The application relates to the technical field of energy storage, and discloses a charging system and a charging method of a flow battery, wherein the charging system comprises a first voltage regulating unit, a three-phase isolation transformer, a first rectifying unit, a second rectifying unit and a balancing filtering unit, wherein the first voltage regulating unit is suitable for carrying out voltage regulating treatment on three-phase alternating current, the three-phase isolation transformer comprises a primary winding, a first secondary winding and a second secondary winding, the primary winding is connected with the first voltage regulating unit, the first rectifying unit is connected with the first secondary winding, the second rectifying unit is connected with the second secondary winding, the balancing filtering unit is suitable for carrying out balancing filtering treatment on parallel output of the first rectifying unit and the second rectifying unit so as to output smooth direct current, the second voltage regulating unit is suitable for carrying out voltage regulating treatment on the smooth direct current, and the control unit is configured to control the first voltage regulating unit and the second voltage regulating unit so as to charge and control the flow battery based on the smooth direct current after the voltage regulating treatment in an initial activation stage, and rapid, reliable and high-quality charging of the flow battery in the initial activation stage is realized.

Inventors

XIN SHISHUAI
ZHANG ZHENLEI
LI XUEWEI
LIU SHUWEI
LI ZONG

Assignees

大连融科储能技术发展有限公司

Dates

Publication Date: 20260512
Application Date: 20260210

Claims (10)

1. A charging system for a flow battery, comprising: The first voltage regulating unit is suitable for carrying out voltage regulating treatment on the input three-phase alternating current; The three-phase isolation transformer comprises a primary winding, a first secondary winding and a second secondary winding, and the primary winding is connected with the first voltage regulating unit; The input end of the first rectifying unit is connected with the first secondary winding; the input end of the second rectifying unit is connected with the second secondary winding, and the output end of the second rectifying unit is connected with the output end of the first rectifying unit in parallel; the first input end of the balance filtering unit is connected with the positive output end of the first rectifying unit and the positive output end of the second rectifying unit respectively, the second input end of the balance filtering unit is connected with the negative output end of the first rectifying unit and the negative output end of the second rectifying unit respectively, and the balance filtering unit is suitable for carrying out balance filtering treatment on the parallel output of the first rectifying unit and the second rectifying unit so as to output smooth direct current; The second voltage regulating unit is suitable for carrying out voltage regulating treatment on the smooth direct current; And the control unit is configured to control the first voltage regulating unit and the second voltage regulating unit so as to control the charging of the flow battery based on the smooth direct current after the voltage regulating treatment in the initial activation stage.
2. The charging system of a flow battery according to claim 1, wherein the first voltage regulating unit comprises: a first three-phase controllable switch; The three-phase voltage regulating device comprises a first three-phase controllable switch and a three-phase voltage regulating resistor, wherein the first three-phase controllable switch is connected with the three-phase voltage regulating resistor in series, and then connected with the first three-phase controllable switch in parallel.
3. The charging system of a flow battery according to claim 2, wherein the second voltage regulating unit includes: A first DC switch; And the plurality of direct current voltage regulating branches are respectively connected with the first direct current switches in parallel, and each direct current voltage regulating branch comprises a second direct current switch and a direct current voltage regulating resistor which are connected in series.
4. The charging system of the flow battery according to claim 3, wherein the control unit is further configured to control the second three-phase controllable switch to be turned on first in the initial activation stage to perform rough voltage adjustment on the three-phase alternating current, and to control at least one of the plurality of second direct current switches to be turned on after the input voltage of the balance filter unit is stabilized, so as to charge the flow battery by the smooth direct current after the voltage adjustment treatment, and to control the first three-phase controllable switch to be turned on and the second three-phase controllable switch to be turned off if the charging parameter of the flow battery satisfies a first preset condition, and to control the first direct current switch to be turned on and the corresponding second direct current switch to be turned off after the input voltage of the balance filter unit is stabilized again.
5. The charging system of the flow battery according to claim 4, wherein in the case that the first rectifying unit and the second rectifying unit are three-phase rectifying bridges built with thyristors, respectively, the control unit is further configured to finely adjust the charging current and the charging voltage of the flow battery by adjusting the conduction angle of the thyristors.
6. A charging system for a flow battery according to any of claims 1-3, wherein the primary winding is delta-connected, the first secondary winding is delta-connected, and the second secondary winding is star-connected, wherein the output voltage magnitude of the first secondary winding is equal to the output voltage magnitude of the second secondary winding and is out of phase by 30 °.
7. The charging system of a flow battery according to claim 6, wherein the balance filter unit includes: a first reactor, one end of which is used as a first input end of the balance filter unit; a second reactor, one end of which is used as a second input end of the balance filter unit; One end of the filter capacitor is connected with the other end of the first reactor, and the other end of the filter capacitor is connected with the other end of the second reactor; and the filter resistor is connected with the filter capacitor in parallel.
8. The charging system of the flow battery according to claim 7, wherein a first capacitor is further connected in parallel between the positive output terminal and the negative output terminal of the first rectifying unit, and a second capacitor is further connected in parallel between the positive output terminal and the negative output terminal of the second rectifying unit.
9. A method of charging a flow battery, wherein the flow battery is charged based on the charging system of any one of claims 1-8, the method comprising: in the initial activation stage, confirming that the charging system and the flow battery meet preset charging conditions; and controlling the first voltage regulating unit and the second voltage regulating unit to perform constant-current charging and constant-voltage charging on the flow battery.
10. The method for charging a flow battery according to claim 9, wherein the first voltage regulating unit comprises a first three-phase controllable switch, a second three-phase controllable switch and a three-phase voltage regulating resistor, the second three-phase controllable switch is connected in parallel with the first three-phase controllable switch after being connected in series with the three-phase voltage regulating resistor, the second voltage regulating unit comprises a first direct current switch and a plurality of direct current voltage regulating branches respectively connected in parallel with the first direct current switch, each direct current voltage regulating branch comprises a second direct current switch and a direct current voltage regulating resistor which are connected in series, and the method comprises the steps of: Firstly controlling the second three-phase controllable switch to be closed so as to carry out rough voltage adjustment on the three-phase alternating current, and controlling at least one of the second direct current switches to be closed after the input voltage of the balance filtering unit is stable so as to charge the flow battery by the smooth direct current after voltage adjustment treatment; And under the condition that the charging parameters of the flow battery meet a first preset condition, controlling the first three-phase controllable switch to be closed and the second three-phase controllable switch to be opened, and controlling the first direct current switch to be closed and the corresponding second direct current switch to be opened after the input voltage of the balance filtering unit is stabilized again.

Description

Charging system and charging method of flow battery Technical Field The application relates to the technical field of energy storage, in particular to a charging system of a flow battery and a charging method of the flow battery. Background Along with the rapid growth of new energy installation, the power grid is subjected to various negative effects such as difficult digestion, poor stability and increased investment requirements, and the long-term energy storage technology can better solve the problems such as new energy digestion, so that the long-term energy storage technology of large-scale deployment represented by the all-vanadium redox flow battery gradually enters the public view. However, in the initial stage of construction or when the redox flow battery is overhauled and restarted, the battery must be initially charged, but most of PCS (Power Conversion System, energy storage converters) in the market are developed based on the functions of lithium battery products, and PCS developed for the features of the redox flow battery are not available, so that the standard PCS cannot initially charge the redox flow battery, which results in that the redox flow battery cannot be directly matched with the standard PCS in the early construction and debugging stages. If the PCS product functions are customized, the PCS can be customized in a pre-charging resistor mode, and hardware and software logic need to be redeveloped, so that the internal space of equipment can be influenced, and even the type test report of a standard product can be influenced. Or when the charging circuit is built by adopting a switching power supply or a half-control rectification mode to initially charge the flow battery, the charging efficiency is reduced and the aging of electrode materials is accelerated due to higher energy consumption in the charging process and larger alternating current ripple on the output direct current component under the high-power application scene. Disclosure of Invention The application aims to provide a charging system and a charging method of a flow battery, which realize high-efficiency, stable and reliable conversion of three-phase alternating current by adopting a three-phase 12-pulse rectification technology on the premise of not affecting the structure of the existing energy storage system, and rapidly establish electrode potential for the flow battery in a high-current constant-current charging mode to establish charging voltage, so that the flow battery can be rapidly and reliably charged with high quality in an initial activation stage, and the charging system is flexible and reliable in product application, relatively simple in structure, good in electric energy quality, friendly to a power grid and capable of solving the problems of high harmonic, low power factor, high current ripple and the like caused by adopting a switching power supply or a semi-controlled rectification charging mode. In order to achieve the above purpose, the main technical scheme adopted by the application comprises the following steps: In a first aspect, the embodiment of the application provides a charging system of a flow battery, which comprises a first voltage regulating unit, a three-phase isolation transformer, a first rectifying unit, a second rectifying unit, a balancing filter unit, a first input end and a second input end, wherein the first voltage regulating unit is suitable for carrying out voltage regulating treatment on input three-phase alternating current, the three-phase isolation transformer comprises a primary winding, a first secondary winding and a second secondary winding, the primary winding is connected with the first voltage regulating unit, the input end of the first rectifying unit is connected with the first secondary winding, the input end of the second rectifying unit is connected with the second secondary winding, the output end of the second rectifying unit is connected with the output end of the first rectifying unit in parallel, the first input end of the balancing filter unit is connected with the positive output end of the first rectifying unit and the positive output end of the second rectifying unit respectively, the second input end of the balancing filter unit is connected with the negative output end of the first rectifying unit and the negative output end of the second rectifying unit respectively, the balancing filter unit is suitable for carrying out voltage regulating treatment on the first voltage regulating unit and the second voltage regulating unit in parallel, and the second voltage regulating unit is suitable for carrying out voltage regulating and smoothing treatment on the first voltage regulating unit and the second voltage regulating unit and then carrying out the first voltage regulating and the second voltage regulating unit to carry out the smoothing control. According to the charging system of the flow battery, provided by the embodiment of the application