Rapid switching device based on digital energy reconstruction system

Abstract

The invention discloses a rapid switching device based on a digital energy reconstruction system, which belongs to the technical field of energy storage of a new energy power system and comprises the digital energy reconstruction system and a switching loop. The digital energy reconstruction system is used for monitoring and managing the operation state of the battery module and controlling the on-off of the battery module as required; and the switching loop is used for realizing rapid control of energy exchange between the battery module and the power grid. Through series-parallel connection of the IGBT modules, switching and protection effects of a traditional switch in a direct-current system can be replaced; based on a current mainstream rapid power electronic device IGBT, on-off of an electrical main loop of the digital energy storage system can be realized at a microsecond level, and system safety is protected in time.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage of new energy power systems, and in particular to a fast switching device based on a digital energy reconstruction system. Background Art

[0002] The main performance indicators of battery energy storage systems, such as efficiency, reliability and safety, are crucial to the safe operation and successful commercial deployment of energy storage systems. The digital energy reconstruction system discretizes and digitizes the battery analog energy flow, transforms the physical hard connection between battery cells into a flexible connection controlled by a program, and thus transforms the analog battery energy storage system into a digital battery energy storage system. This fundamentally solves the industry pain points in terms of safety and economy caused by the short board effect of the battery system, and thus achieves seamless integration with the information Internet industry. As a disruptive technology of the energy Internet, digital energy storage has transformative significance for the future development of the energy storage industry.

[0003] In the digital energy reconstruction system, the battery system is quickly put into use when in use, and is quickly cut out of the system in case of failure to protect the battery from damage. The traditional solution is to use a contactor or a fast switch based on traditional power electronics, such as a fast thyristor as a switch, but its response speed still cannot meet the technical requirements of digital battery energy storage. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a fast switching device based on a digital energy reconstruction system.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A fast switching device based on a digital energy reconstruction system, comprising a digital energy reconstruction system and a switching circuit;

[0007] The digital energy reconstruction system is responsible for monitoring and managing the operating status of the battery module and controlling the on and off of the battery module as needed;

[0008] The switching circuit is used to achieve rapid control of energy exchange between the battery module and the power grid.

[0009] Furthermore, the positive pole of the switching circuit is connected to the battery system of the digital energy reconstruction system to achieve differentiated inclusion of second-life battery utilization; the negative pole of the switching circuit is connected to the AC bus to achieve energy exchange with the power grid.

[0010] Furthermore, the switching circuit adopts a design method of arranging IGBT modules and diode pairs.

[0011] Further, the switching circuit is a switching circuit of a half-bridge IGBT module + diode.

[0012] Further, the switching circuit is a switching circuit of a multi-bridge-arm IGBT module + diode.

[0013] Further, the IGBT module includes an insulated gate bipolar transistor and an anti-parallel diode.

[0014] Further, in the switching circuit, the working current is increased by paralleling the IGBT modules in the current direction.

[0015] Further, in the switching circuit, according to the different magnitudes of the current passing through, the number of IGBT modules turned on in the series direction is different.

[0016] Further, in the digital energy reconstruction system, for the control of the number of IGBT modules invested for different power levels, it includes:

[0017] Allocate 2 n IGBT modules for series-parallel connection on the battery system side, and allocate 2 n diodes in parallel on the AC bus side, where n ≥ 1 and n represents the number of branches;

[0018] If the operating power of the digital energy reconstruction system is P, then the power P1 that each branch can withstand is:

[0019] P1 = P / (2 n / 2);

[0020] If the power ratio is m, 0 < m ≤ 100%, then calculate the number of IGBT branches n1 to be invested, 1 ≤ n1 ≤ 2 n / 2, n1 is the number of branches to be invested at different powers, and the calculation formula is as follows:

[0021] n1 = mP / P1.

[0022] Further, if n1 is calculated as a non-integer, round up to the nearest integer for branch investment.

[0023] In summary, compared with the prior art, the beneficial effects of the above technical solutions are:

[0024] The present invention can replace the traditional switches in the switching and protection functions of the DC system through the series and parallel connection of IGBT modules. The traditional switches, whether contactors or control methods based on switching devices such as thyristors, have a response time of milliseconds, and their response time increases with the increase of current. At the same time, due to technical bottlenecks, there are often no matching conventional products in a larger voltage and current environment, and the technical parameters of new development or production cannot be guaranteed. The present invention can intelligently control the number of IGBTs invested according to the system capacity, which can effectively reduce losses and increase the life of IGBTs. Based on the current mainstream fast power electronic device insulated gate bipolar transistor, i.e. IGBT, the present invention can realize the opening and closing of the electrical main circuit of the digital energy storage system in microseconds, and timely protect the safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is a topological diagram of a half-bridge IGBT module + diode switching circuit according to an embodiment of the present invention;

[0027] Figure 2 This is a topological diagram of a multi-bridge-arm IGBT module + diode switching circuit according to an embodiment of the present invention;

[0028] Figure 3 The figure is a flow chart of judging whether to start the IGBT under different power conditions according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The principles and features of the present invention are described below in conjunction with all the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0030] Traditional switches, whether they are contactors or control methods based on switch devices such as thyristors, have a response time of milliseconds, and their response time increases with the increase of current. From the above description, it can be seen that traditional switches have a slow response time, and the response time increases with the increase of current, which cannot meet the needs of digital energy storage systems for fast action in microseconds. The present invention adopts a combination of fast power electronic devices, insulated gate bipolar transistors (IGBTs) and diodes, and realizes rapid switching of battery clusters in digital energy storage systems in a series-parallel manner. At the same time, two coils are used on one side of the switching circuit to reduce the difficulty of control.

[0031] Reference Figure 1-Figure 3, an embodiment of the present invention discloses a fast switching device based on a digital energy reconstruction system, including a digital energy reconstruction system and a switching circuit;

[0032] The digital energy reconstruction system is responsible for monitoring and managing the operating status of the battery module and controlling the on and off of the battery module as needed;

[0033] The switching circuit is used to achieve rapid control of energy exchange between the battery module and the power grid; the switching circuit adopts the design of IGBT module and diode pair arrangement, and realizes rapid switching of battery clusters in the digital energy storage system through series and parallel connection. Furthermore, the positive pole of the switching circuit is connected to the battery system of the digital energy reconstruction system, namely the BAT side, to achieve differentiated inclusion of the use of second-life batteries; the negative pole of the switching circuit is connected to the AC bus, namely the PCS side, to achieve energy exchange with the power grid.

[0034] In this embodiment, the digital energy reconstruction system includes an energy block and an energy control module, and the energy block is a reconfigurable battery network; the energy control module is used to obtain the operating parameters of each battery module in the energy block when the energy block is charging or discharging, and control the on and off of each battery module by controlling the switch of each battery module in the energy block based on the acquired operating parameters.

[0035] When the energy block needs to discharge, the energy control module controls the opening and closing of the switching circuit according to the status information of the battery module to quickly and accurately transmit the energy in the battery cluster to the grid. When the energy block needs to be charged, the energy of the grid is transmitted to the battery cluster through the opposite process. In the event of a fault, the switching circuit can cut off the electrical connection between the battery side and the grid side within microseconds to protect the system safety.

[0036] In the embodiment of the present invention, an IGBT module and a diode pair are arranged. The microsecond response speed of the IGBT module can cut off the electrical connection between the battery side and the PCS side more quickly in case of a fault. At the same time, with precise adoption and control circuits, the safety of the digital energy storage system can be greatly improved under different working conditions. At the same time, according to the power flow direction, the IGBT at the corresponding position is turned on, avoiding the problem of reverse flow of power or current in case of a fault.

[0037] like Figure 1As shown, an embodiment of the present invention shows a topological diagram of a half-bridge IGBT module + diode switching circuit, wherein the switching circuit includes an upper bridge arm and a lower bridge arm, wherein the upper bridge arm is the IGBT module T1, and the lower bridge arm is the IGBT module T2. The IGBT module includes an insulated gate bipolar transistor and an anti-parallel diode. The insulated gate bipolar transistor has the advantages of low driving power, fast switching speed, low on-state voltage drop, and strong current carrying capacity. The anti-parallel diode can make the insulated gate bipolar transistor bidirectionally conductive, and can also protect the insulated gate bipolar transistor from being broken down by reverse high voltage. The two poles of the switching circuit constitute the two poles of the microsecond switching circuit, which are the positive pole of the switching circuit and the negative pole of the switching circuit.

[0038] If the power flows from the BAT side to the PCS side, the IGBT module T2 is turned on, and the energy flows to the PCS side through the IGBT module T2 and the diode D2 to achieve this function. At this time, if a fault occurs, since the IGBT module T1 is turned off, the built-in diode of the IGBT module T1 is reversed, which prevents the energy from flowing from the PCS side to the BAT side. That is, in the embodiment of the present invention, the lower bridge arm IGBT module T2 is turned on during discharge, and the upper bridge arm IGBT module T1 is turned on during charging.

[0039] like Figure 2 As shown, the embodiment of the present invention also shows a topological diagram of a switching circuit of a multi-bridge arm IGBT module + a diode, which can be regarded as a switching circuit of a combination of multiple IGBT modules. The specific working logic is:

[0040] Combination Figure 1 The operating logic shown in the figure is that in order to increase the operating current, multiple IGBT modules are connected in parallel in the current direction. Figure 2 In the BAT side, 2 n IGBTs are connected in series and parallel (n≥1), and 2 n When n diodes are connected in parallel (n≥1), the circuit can withstand a proportional increase in current.

[0041] As in Figure 1 In the equation, n=1, the maximum current flowing is A;

[0042] Figure 2 In the case of n=4, the maximum current flowing is 2A;

[0043] When n=6 / 8 / 10…, the current flowing increases in the same proportion;

[0044] Figure 2 In the scheme shown, under different current conditions, the IGBT can still be partially turned on according to the IGBT parameters. At the same time, in this topology, the number of IGBTs is greater, which is more effective in reducing losses and increasing the life of the IGBT.

[0045] The energy flow direction is controlled by the IGBT module T1 and the IGBT module T2, and fast switching is achieved at the same time. When charging, the lower-arm IGBT module T2 is turned on, and when discharging, the upper-arm IGBT module T1 is turned on. This avoids the ineffective turn-on of the IGBT and restricts the energy flow in the abnormal control direction.

[0046] By paralleling the tubes such as the IGBT module T1, the IGBT module T3, and the IGBT module T5, the increase of the current can be achieved.

[0047] According to the different magnitudes of the current flowing through, the number of longitudinal IGBT modules to be turned on can be selected. For example, for the rated current, all the IGBT modules are turned on. If the current is lower than a certain value, some of the IGBT modules are turned on. By paralleling multiple IGBT modules in the current direction, a larger current flow can be achieved, as Figure 2 shown.

[0048] In practical applications, for the control of the number of IGBTs input for different power levels, it is first necessary to determine the power that each IGBT module or branch can withstand. Then, according to the total power demand and power ratio of the system, the number of IGBT modules to be input is calculated. Specifically, through the following methods:

[0049] (1) Determine the power of each branch;

[0050] As Figure 2 shown, to increase the current-carrying capacity of the topology, 2 n IGBT modules are allocated on the BAT side, n≥1, where n represents the number of branches. If the operating power of the system is P, then the power P1 that each branch can withstand is:

[0051] P1 = P / (2 n / 2);

[0052] Figure 2 Among them, each branch includes two IGBT modules and two diodes. For example, a branch includes the IGBT module T1, the IGBT module T2, the diode D1, and the diode D2.

[0053] (2) Calculate the number of IGBT module branches to be input;

[0054] In different power ranges, if the power ratio is m (0 < m ≤ 100%), then the number of IGBT branches n1 (1 ≤ n1 ≤ 2 n / 2) to be input can be calculated through the following formula. n1 is the number of IGBT branches that need to be input on both the battery side and the PCS side:

[0055] n1 = mP / P1;

[0056] According to the above formula, if the calculated n1 is 1, the minimum number of branches put into operation is 1, that is, 1 branch is put into operation on the battery side and the PCS side. If the calculated n1 is a non-integer, it is necessary to round up to the nearest integer to put the branch into operation to ensure that the power capacity of the IGBT module is greater than the operating power to avoid IGBT overload damage. In the actual control process, in order to ensure the power circuit, n1≥1 needs to be set when the power is 0.

[0057] The present invention can replace the traditional switches in the switching and protection functions of the DC system through the series and parallel connection of IGBT modules. The traditional switches, whether contactors or control methods based on switching devices such as thyristors, have a response time of milliseconds, and their response time increases with the increase of current. At the same time, due to technical bottlenecks, there are often no matching conventional products in a larger voltage and current environment, and the technical parameters of new development or production cannot be guaranteed. The present invention can intelligently control the number of IGBTs invested according to the system capacity, which can effectively reduce losses and increase the life of IGBTs. Based on the current mainstream fast power electronic device insulated gate bipolar transistor, i.e. IGBT, the present invention can realize the opening and closing of the electrical main circuit of the digital energy storage system in microseconds, and timely protect the safety of the system.

[0058] Based on the same inventive concept, an embodiment of the present invention also provides a method for realizing a fast switching device based on a digital energy reconstruction system involved in the above-mentioned fast switching device based on a digital energy reconstruction system. The implementation scheme for solving the problem provided by the system is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in one or more system embodiments provided below can refer to the above-mentioned limitations on a fast switching device based on a digital energy reconstruction system, and will not be repeated here.

[0059] In one embodiment, referring to Figure 3 , provides a fast switching method based on a digital energy reconstruction system, comprising the following steps:

[0060] The digital energy reconstruction system starts to run, and the energy control module continuously monitors the energy block, that is, the operating parameters of each battery module in the battery cluster, wherein the operating parameters of the battery module include voltage and current;

[0061] According to the operating power P of the digital energy reconstruction system, calculate the power P1 that each branch can bear; according to the required power ratio m, calculate the number of IGBT modules that need to be invested;

[0062] According to the determined number of IGBT modules to be put into use, a corresponding number of IGBT modules are put into use simultaneously on the battery cluster side and the AC bus side;

[0063] By connecting the IGBT modules in series and in parallel, the energy exchange between the battery cluster and the power grid can be quickly controlled.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A fast switching device based on a digital energy reconstruction system, characterized in that: Including digital energy reconstruction system and switching circuit; The digital energy reconstruction system is responsible for monitoring and managing the operating status of the battery module and controlling the on and off of the battery module as needed; The switching circuit is used to achieve rapid control of energy exchange between the battery module and the power grid.

2. According to claim 1, a fast switching device based on a digital energy reconstruction system is characterized in that: The positive pole of the switching circuit is connected to the battery system of the digital energy reconstruction system to achieve differentiated inclusion of second-life battery utilization; the negative pole of the switching circuit is connected to the AC bus to achieve energy exchange with the power grid.

3. According to claim 1, a fast switching device based on a digital energy reconstruction system is characterized in that: The switching circuit adopts the design mode of IGBT module and diode pair arrangement.

4. According to claim 3, a fast switching device based on a digital energy reconstruction system is characterized in that: The switching circuit is a switching circuit of a half-bridge IGBT module+diode.

5. According to claim 3, a fast switching device based on a digital energy reconstruction system is characterized in that: The switching circuit is a switching circuit of a multi-bridge-arm IGBT module+diode.

6. A fast switching device based on a digital energy reconstruction system according to claim 3, characterized in that: The IGBT module includes an insulated gate bipolar transistor and an anti-parallel diode.

7. The fast switching device based on the digital energy reconstruction system according to claim 3 is characterized in that: In the switching circuit, the operating current is increased in the current direction by connecting IGBT modules in parallel.

8. The fast switching device based on the digital energy reconstruction system according to claim 3 is characterized in that: In the switching circuit, the number of IGBT modules turned on in the series direction varies depending on the size of the current.

9. The fast switching device based on the digital energy reconstruction system according to claim 3 is characterized in that: In the digital energy reconstruction system, the control of the number of IGBT modules invested in different power levels includes: Allocate 2 on the battery system side n IGBT modules are connected in series and parallel, and 2 n diodes are connected in parallel, where n≥1, and n represents the number of branches; If the operating power of the digital energy reconstruction system is P, the power P1 that each branch can withstand is: P1=P / (2 n / 2); If the power ratio is m, where 0 < m ≤ 100%, then calculate the number of IGBT branches n1 to be put into operation, where 1 ≤ n1 ≤ 2 n / 2. n1 is the number of branches to be put into operation at different powers, and the calculation formula is as follows: n1=mP / P1.

10. A fast switching device based on a digital energy reconstruction system according to claim 9, characterized in that: If the calculated n1 is not an integer, round it up to the nearest integer and put the branch into operation.

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