High-voltage series super-capacitor cluster charging and discharging system and voltage-sharing protection method thereof

Abstract

The invention provides a high-voltage series super-capacitor cluster charging and discharging system. The high-voltage series super-capacitor cluster charging and discharging system comprises a plurality of power modules. The single power module includes: a first semiconductor device; the second semiconductor device is connected with the first semiconductor device in series and is connected to a super capacitor cluster; the bypass switch is connected with the second semiconductor device in parallel; and the third semiconductor device is connected with the bypass switch in parallel, and the third semiconductor device is connected to an input port. The invention further provides a fault protection method of the high-voltage series super-capacitor cluster charging and discharging system, and through actions of the bypass switch and the third semiconductor device, it is ensured that after the power module breaks down, work is stopped in time, and operation of the system is not affected. According to the high-voltage series super-capacitor cluster charging and discharging system provided by the invention, through the arrangement of the first semiconductor device and the second semiconductor device, the switching state of the corresponding power module is controlled, and the dynamic voltage sharing of the super-capacitor cluster is realized.

Description

Technical Field

[0001] The present application relates to the field of power electronic control technology, and in particular to a high-voltage series supercapacitor cluster charging and discharging system and a voltage balancing protection method thereof. Background Art

[0002] As a new type of energy storage element, supercapacitors have the advantages of high power density, fast charging and discharging speed, strong temperature adaptability, long life, low maintenance cost and flexible construction methods. In the application field of supercapacitor high-voltage series connection, such as static synchronous condenser (SSC), grid control technology, high-voltage cascade and supercapacitor short-term energy storage are used to instantly share active power during faults, provide inertia support for the system, help improve the overall short-circuit capacity of grid nodes, and improve the "through" fault capability of grid-connected equipment.

[0003] In order to facilitate overcapacity management, a one-cluster-one-management solution for overcapacitors is generally adopted. A number of overcapacitors are connected in series and parallel, which is called a cluster. The back stage of each power module is connected to a cluster of overcapacitors. After the power modules are cascaded, they form a branch and are connected to the DC side of the synchronous phase regulator. A branch is composed of several cascaded overcapacitor clusters; an overcapacitor cluster is composed of multiple overcapacitors connected in series and parallel. During charging and discharging or energy storage, due to the discreteness of characteristic parameters, each overcapacitor may have an uneven voltage problem. The current of a branch is the same, and the uneven voltage problem will affect the service life of the overcapacitor, and then endanger the entire branch. Summary of the invention

[0004] The present application provides a high-voltage series super-capacitor cluster charging and discharging system and a voltage-balanced protection method thereof to solve the problem of uneven voltage in the super-capacitor cluster. If the uneven voltage between super-capacitor cells reaches a certain level, the corresponding super-capacitor cluster and power module are bypassed and exit work without affecting the operation of the system.

[0005] In order to solve the above technical problems, the present application provides a high-voltage series supercapacitor cluster charging and discharging system, including several power modules, wherein the power module includes: a first semiconductor device; a second semiconductor device connected in series with the first semiconductor device; a bypass switch connected in parallel with the second semiconductor device; a third semiconductor device connected in parallel with the bypass switch, and the third semiconductor device is connected to an input port. The output port of the power module is connected to the supercapacitor cluster.

[0006] Furthermore, the power module further includes a filter capacitor, and the filter capacitor is connected to the first semiconductor device and the second semiconductor device.

[0007] Furthermore, the power module further comprises a fuse and a circuit breaker, and the fuse and the circuit breaker are connected in series between the supercapacitor cluster and the filter capacitor.

[0008] The present invention also provides a voltage balancing protection method for a high-voltage series supercapacitor cluster charging and discharging system. When the high-voltage series supercapacitor cluster is in a charging state, the second semiconductor device in the power module with a higher voltage is turned on, and the first semiconductor device in the power module with a higher voltage is turned off; when the high-voltage series supercapacitor cluster is in a discharging state, the second semiconductor device in the power module with a lower voltage is turned on, and the first semiconductor device in the power module with a lower voltage is turned off.

[0009] Further, when the first semiconductor device and / or the second semiconductor device fails, the bypass switch is closed, the system current flows through the bypass switch, and the power module exits operation.

[0010] Furthermore, when the bypass switch cannot be closed normally, the voltage of the filter capacitor reaches a set threshold, the third semiconductor device is broken down, the system current flows through the third semiconductor device, and the power module exits operation.

[0011] The present invention provides a voltage balancing protection method for a high-voltage series super-capacitor cluster charging and discharging system, which controls the switching state of the power module by turning off and on the first semiconductor device and the second semiconductor device, thereby realizing dynamic voltage balancing of the super-capacitor cluster. Furthermore, by setting the third semiconductor device, when the bypass switch cannot be closed normally, it can also ensure that the power module exits operation in time without affecting the overall operation of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0013] Figure 1 A schematic diagram of the DC side branch connection in the high voltage series supercapacitor cluster charging and discharging system provided by an embodiment of the present invention;

[0014] Figure 2 A schematic diagram of the electrical connection of power modules in a high-voltage series super-capacitor cluster charging and discharging system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0016] In the description of the present application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0017] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0018] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0019] Figure 1 A schematic diagram of the DC side branch connection in the high-voltage series super-capacitor cluster charging and discharging system provided in an embodiment of the present invention; the DC side of the synchronous phase regulator corresponds to P and Q. P is the positive terminal and Q is the negative terminal. After several power modules are cascaded, a branch is formed, which is connected between PQ. Multiple branches can be connected in parallel between PQ. Two branches are shown in the figure. The rear stage of the power module is connected to the super-capacitor cluster, refer to Figure 1 , a high-voltage series super-capacitor cluster charging and discharging system provided by an embodiment of the present invention includes several power modules. Figure 2 Schematic diagram of the electrical connection of the power module in the high-voltage series super-capacitor cluster charging and discharging system provided by the embodiment of the present invention. AB is the input port, and CD is the output port. The CD port is connected to the super-capacitor (such as Figure 1 As shown). C is the positive electrode and D is the negative electrode. The power module comprises: a first semiconductor device T1; a second semiconductor device T2 connected in series with the first semiconductor device T1; a bypass switch K1 connected in parallel with the second semiconductor device T2; a third semiconductor device T3 connected in parallel with the bypass switch K1, and the third semiconductor device T3 is connected to the input port AB.

[0020] In an embodiment of the invention, the power module further includes a filter capacitor, a fuse and a circuit breaker. The filter capacitor C1 is connected to the first semiconductor device and the second semiconductor device; the fuses F1, F2 and the circuit breakers Q1, Q2 are connected in series between the supercapacitor cluster and the filter capacitor. When the power module operates normally, the circuit breakers Q1, Q2 are in a closed state, the bypass switch K1 is in an open state, and the third semiconductor device T3 is in a blocked state, presenting a high-impedance characteristic to the outside.

[0021] When the supercapacitor cluster is charged, the current flows in from point A, flows through the diode of the first semiconductor device T1, then flows through the circuit breaker Q1 and the fuse F1, and reaches the positive electrode of the supercapacitor. After flowing through the supercapacitor, it flows through the fuse F2 and the circuit breaker Q2, and reaches point B; when the supercapacitor is discharged, the current flows out from the positive electrode of the supercapacitor cluster, flows through the fuse F1 and the circuit breaker Q1, and then flows through the IGBT of the first semiconductor device T1, and reaches port A. Each power module is cascaded (such as Figure 1 As shown in the figure, the overcapacitor clusters in the same branch discharge synchronously, and the current eventually flows into the positive electrode P on the DC side of the synchronous condenser. The current flows out from the negative electrode Q on the DC side of the synchronous condenser, reaches point B of the power module, flows through the circuit breaker Q2 and the fuse F2, and reaches the negative electrode of the overcapacitor cluster.

[0022] The present invention also provides a dynamic voltage equalization method for a high-voltage series supercapacitor cluster charging and discharging system. When the high-voltage series supercapacitor cluster is in a charging state, the second semiconductor device in the power module with a higher voltage is turned on, and the first semiconductor device in the power module with a higher voltage is turned off; the branch current flows through the second semiconductor device in the power module and does not flow through the supercapacitor cluster corresponding to the power module, so the voltage of other supercapacitor clusters in the system will increase. After a period of time, the voltage of all supercapacitor clusters will tend to be balanced.

[0023] When the high-voltage series supercapacitor cluster is in a discharging state, the second semiconductor device in the power module with a lower voltage is turned on, and the first semiconductor device in the power module with a lower voltage is turned off, and the supercapacitor cluster corresponding to the power module stops discharging. After a period of time, the voltages of all supercapacitor clusters tend to be balanced.

[0024] When the first semiconductor device and / or the second semiconductor device fails, a discharge loop is formed, and the overcapacitor cluster continues to discharge with a large current, causing fuses F1 and F2 to burn out, and the power module and the overcapacitor cluster are disconnected. At this time, the control system detects the power module failure and issues a bypass switch closing instruction. The bypass switch is closed, the system current flows through the bypass switch, the power module exits operation, and the equipment does not need to be shut down and operates uninterruptedly.

[0025] When the bypass switch fails to close normally due to a fault or an abnormal closing trigger circuit, the charging current of the branch continues to flow into the power module through the diode of the first semiconductor device T1. Figure 2 The voltage between points F and G in the circuit will increase rapidly. When the voltage reaches the set threshold, the third semiconductor device T3 is broken down, and the third semiconductor device T3 is in a low-resistance state to the outside. The system current can flow through the broken-down third semiconductor device T3 to bypass the power module, and the power module will exit operation. The equipment does not need to be shut down and operates uninterruptedly.

[0026] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection created by this application.

Claims

1. A high-voltage series super-capacitor cluster charging and discharging system, comprising a plurality of power modules, characterized in that: The power module comprises: a first semiconductor device; a second semiconductor device, connected in series with the first semiconductor device; a bypass switch connected in parallel with the second semiconductor device; a third semiconductor device connected in parallel with the bypass switch, the third semiconductor device being connected to an input port; The output port of the power module is connected to the super-capacity cluster.

2. The high-voltage series supercapacitor cluster charging and discharging system according to claim 1 is characterized in that: The power module further includes a filter capacitor connected to the first semiconductor device and the second semiconductor device.

3. The high-voltage series supercapacitor cluster charging and discharging system according to claim 1 is characterized in that: The power module further comprises a fuse and a circuit breaker, wherein the fuse and the circuit breaker are connected in series between the supercapacitor cluster and the filter capacitor.

4. A voltage balancing protection method for a high-voltage series supercapacitor cluster charging and discharging system as claimed in claim 1, characterized in that: When the high-voltage series super-capacitor cluster is in a charging state, the second semiconductor device in the power module with a higher voltage is turned on, and the first semiconductor device in the power module with a higher voltage is turned off; when the high-voltage series super-capacitor cluster is in a discharging state, the second semiconductor device in the power module with a lower voltage is turned on, and the first semiconductor device in the power module with a lower voltage is turned off.

5. The voltage balancing protection method for a high-voltage series supercapacitor cluster charging and discharging system according to claim 4, characterized in that: include: When the first semiconductor device and / or the second semiconductor device fails, the bypass switch is closed, the system current flows through the bypass switch, and the power module stops operating.

6. The voltage balancing protection method for a high-voltage series supercapacitor cluster charging and discharging system according to claim 4, characterized in that: include: When the bypass switch cannot be closed normally, the voltage of the filter capacitor reaches a set threshold, the third semiconductor device is broken down, the system current flows through the third semiconductor device, and the power module exits operation.

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