Converter DC bus protection device

Abstract

The present invention discloses a converter DC bus protection device, which comprises: a switching module and a plurality of protection circuits with different functions, wherein the plurality of protection circuits are used to be connected between the DC bus and the DC load to protect the DC bus, and the switching module is used to switch the protection circuits connected between the DC bus and the DC load. By adopting the technical solution of the present invention, the DC bus of the converter can be protected with multiple functions.

Description

Technical Field

[0001] The present invention relates to the field of converters, and in particular to a converter DC bus protection device. Background Art

[0002] With the development of the new energy industry, converters or converter units, as the basic energy conversion part, play a vital role. Converters are generally composed of basic topologies such as DC / DC, AC / DC or DC / AC, where the DC voltage is the DC bus voltage, which is usually tens of volts to hundreds of volts.

[0003] The DC bus may have the following fault problems: 1. The bus capacitor explodes and the DC load on the DC bus is damaged due to reverse polarity of the DC bus; 2. The residual charge of the bus capacitor on the DC bus is discharged slowly; 3. The DC load is slow to adjust immediately, and the DC load can only be adjusted after the system power supply is disconnected; 4. The short circuit caused by the DC load's own fault leads to a short circuit in the DC bus.

[0004] If the DC bus is not properly protected, it may cause the inverter to fail and even affect the normal operation of the entire system. Summary of the invention

[0005] The purpose of the present invention is to provide a converter DC bus protection device which can effectively protect the DC bus of the converter in view of the technical problems in the above-mentioned prior art.

[0006] In an embodiment of the present invention, a converter DC bus protection device is provided, which includes a switching module and multiple protection circuits with different functions, the multiple protection circuits are used to be connected between the DC bus and the DC load to protect the DC bus, and the switching module is used to switch the protection circuit connected between the DC bus and the DC load.

[0007] In an embodiment of the present invention, the protection circuit includes a first connection terminal, a second connection terminal, a third connection terminal and a fourth connection terminal respectively used to connect to the positive connection terminal, the negative connection terminal of the DC bus, and the positive connection terminal and the negative connection terminal of the DC load, and the switching module is used to control the connection and disconnection of the four connection terminals of the protection circuit with the positive connection terminal, the negative connection terminal of the DC bus, and the positive connection terminal and the negative connection terminal of the DC load.

[0008] In an embodiment of the present invention, the switching module includes a rotating component for carrying the multiple protection circuits. When the rotating component rotates to a set angle, the four connection terminals of the protection circuit are just connected to the positive connection terminal, negative connection terminal of the DC bus, and the positive connection terminal and negative connection terminal of the DC load.

[0009] In an embodiment of the present invention, the switching module also includes a driving circuit, a stepper motor and a rotating shaft, the rotating shaft is connected to the rotating component, the stepper motor is connected to the rotating shaft, the driving circuit is connected to the stepper motor, and the driving circuit is used to send a driving signal to drive the stepper motor to rotate and drive the rotating component to rotate.

[0010] In the embodiment of the present invention, the four connection terminals of the protection circuit are arranged at the four corners of a square centered on the rotation axis.

[0011] In an embodiment of the present invention, the plurality of protection circuits include a reverse polarity protection circuit and a residual charge discharge circuit.

[0012] In an embodiment of the present invention, the reverse polarity protection circuit includes diodes D1, D2, D3, and D4, the first connection end of the reverse polarity protection circuit is respectively connected to the anode of the diode D1 and the cathode of the diode D3, the second connection end of the reverse polarity protection circuit is respectively connected to the cathode of the diode D1 and the cathode of the diode D4, the third connection end of the reverse polarity protection circuit is respectively connected to the anode of the diode D2 and the cathode of the diode D3, and the fourth connection end of the reverse polarity protection circuit is respectively connected to the cathode of the diode D2 and the anode of the diode D4.

[0013] In an embodiment of the present invention, the reverse polarity protection circuit also includes fuses FU1 and FU2, fuse FU1 is connected between the cathode of diode D1 and the second connection end of the reverse polarity protection circuit, and fuse FU2 is connected between the anode of diode D4 and the fourth connection end of the reverse polarity protection circuit.

[0014] In an embodiment of the present invention, the residual charge discharge circuit includes resistors R1, R2, R3, and R4, wherein the resistors R1 and R2 are connected in series between the second connection terminal and the third connection terminal of the residual charge discharge circuit, and the resistors R3 and R4 are connected in series between the first connection terminal and the fourth connection terminal of the residual charge discharge circuit.

[0015] In the embodiment of the present invention, a control module connected to the switching module is further included, and the control module is used to transmit the user's switching instruction to the switching module.

[0016] Compared with the prior art, in the converter DC bus protection device of the present invention, the switching module is used to switch the protection circuit connected between the DC bus and the DC load, so that a variety of different protection functions can be provided for the DC bus according to actual needs; by arranging the four connection ends of the multiple protection circuits on a rotatable rotating component, the multiple protection circuits can be connected and disconnected by rotating the rotating component, thereby realizing different protection functions, and the switching process is simple and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a converter DC bus protection device according to an embodiment of the present invention.

[0018] Figure 2 It is a schematic diagram of the structure of the switching module of an embodiment of the present invention.

[0019] Figure 3 It is a schematic diagram of the normal working state of the converter DC bus protection device according to an embodiment of the present invention.

[0020] Figure 4 It is a schematic diagram of the working state of the converter DC bus protection device in an embodiment of the present invention to realize the anti-reverse connection function.

[0021] Figure 5 It is a schematic diagram of the working state of the converter DC bus protection device according to an embodiment of the present invention to achieve instant DC load adjustment.

[0022] Figure 6 It is a schematic diagram of the working state of the converter DC bus protection device according to an embodiment of the present invention to achieve rapid charge discharge. DETAILED DESCRIPTION

[0023] like Figure 1 As shown, an embodiment of the present invention provides a converter DC bus protection device, which includes a control module, a switching module, a polarity reverse protection circuit and a residual charge discharge circuit. The polarity reverse protection circuit and the residual charge discharge circuit are respectively used to be connected between the DC bus and the DC load to protect the DC bus, the switching module is used to switch the polarity reverse protection circuit and the residual charge discharge circuit connected between the DC bus and the DC load, and the control module is used to transmit the user's switching instruction to the switching module.

[0024] The reverse polarity protection circuit includes diodes D1, D2, D3, D4 and a first connection terminal 1, a second connection terminal 2, a third connection terminal 3 and a fourth connection terminal 4 respectively connected to the positive connection terminal, the negative connection terminal of the DC bus, the positive connection terminal and the negative connection terminal of the DC load. The first connection terminal 1 of the reverse polarity protection circuit is respectively connected to the positive electrode of the diode D1 and the negative electrode of the diode D3, the second connection terminal 2 of the reverse polarity protection circuit is respectively connected to the negative electrode of the diode D1 and the negative electrode of the diode D4, the third connection terminal 3 of the reverse polarity protection circuit is respectively connected to the positive electrode of the diode D2 and the positive electrode of the diode D3, and the fourth connection terminal 4 of the reverse polarity protection circuit is respectively connected to the negative electrode of the diode D2 and the positive electrode of the diode D4. Furthermore, in the reverse polarity protection circuit, fuses FU1 and FU2 are also provided. Fuse FU1 is connected between the cathode of diode D1 and the second connection terminal of the reverse polarity protection circuit, and fuse FU2 is connected between the anode of diode D4 and the fourth connection terminal of the reverse polarity protection circuit. Fuses FU1 and FU2 are used to blow when the DC bus current is too large, thereby protecting the DC bus.

[0025] The residual charge discharge circuit includes resistors R1, R2, R3, R4 and a first connection terminal 5, a second connection terminal 6, a third connection terminal 7 and a fourth connection terminal 8 respectively connected to the positive connection terminal and the negative connection terminal of the DC bus, and the positive connection terminal and the negative connection terminal of the DC load. The resistors R1 and R2 are connected in series between the second connection terminal 6 and the third connection terminal 7 of the residual charge discharge circuit, and the resistors R3 and R4 are connected in series between the first connection terminal 5 and the fourth connection terminal 8 of the residual charge discharge circuit.

[0026] like Figure 2 As shown, the switching module includes a rotating component, a driving circuit, a stepper motor and a rotating shaft. The rotating component is used to carry the multiple protection circuits. When the rotating component rotates to a set angle, the four connection ends of the polarity reverse connection protection circuit or the residual charge discharge circuit are just connected to the positive connection end, the negative connection end of the DC bus, and the positive connection end and the negative connection end of the DC load. The rotating shaft is connected to the rotating component, the stepper motor is connected to the rotating shaft, and the driving circuit is connected to the stepper motor. The driving circuit is used to send a driving signal to drive the stepper motor to rotate, thereby driving the rotating component to rotate. The four connection ends of the polarity reverse connection protection circuit and the residual charge discharge circuit are all arranged at the four corners of a square centered on the rotating shaft, so that when the rotating component rotates to a set angle, the four connection ends of the polarity reverse connection protection circuit or the residual charge discharge circuit are just connected to the positive connection end, the negative connection end of the DC bus, and the positive connection end and the negative connection end of the DC load.

[0027] The working principle of the above converter DC bus protection device is described below.

[0028] like Figure 3 As shown in FIG. 1 , when the DC load is connected normally, the current at the positive end of the DC bus flows into the DC load through the diode D1, and then flows back to the negative end of the DC bus through the diode D2. Figure 4 As shown, when the DC load is reversely connected, the current at the positive end of the DC bus flows into the DC load through the diode D4, and flows back to the negative end of the DC bus through the diode D3, so that the DC load can work normally even when it is reversely connected, avoiding the problem of capacitor explosion and DC load damage caused by reverse polarity.

[0029] like Figure 5 As shown, when a large-capacitance DC load is adjusted or the DC bus voltage needs to be discharged, the rotation angle α is controlled to be 45°, so that the contacts 5-8 are connected to the four connection points, the resistors R1 and R2 are connected in series between the DC loads, and the resistors R3 and R4 are connected in series between the DC buses, and the residual charge of the capacitor can be quickly discharged through the series resistors). The values ​​of the resistors R1, R2, R3, and R4 are related to the discharge time. At the same time, combined with the selected value and power of the DC bus voltage, the residual charge of the capacitor can be quickly discharged, saving time.

[0030] like Figure 6 As shown, when the user needs to replace, maintain or adjust the DC load, the user can directly send relevant instructions to the switching module through the control module. After receiving the instruction information, the switching module will control the stepper motor to rotate a certain angle through the drive circuit, so that the four connection points of the protection circuit are disconnected from the DC bus and the DC load, and indirectly disconnect the electrical connection between the DC bus and the DC load. For some non-capacitive or small-capacitance DC loads, the user can directly adjust them, and then control the DC load to be connected to the DC bus through user instructions and restart the operation. During the whole process, the system does not need to be powered off, and does not affect the operation of the DC bus or the power supply to other DC loads.

[0031] Compared with the prior art, in the converter DC bus protection device of the present invention, the switching module is used to switch the protection circuit connected between the DC bus and the DC load, so that a variety of different protection functions can be provided for the DC bus according to actual needs; by arranging the four connection ends of the multiple protection circuits on a rotatable rotating component, the multiple protection circuits can be connected and disconnected by rotating the rotating component, thereby realizing different protection functions, and the switching process is simple and easy to implement.

[0032] 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 and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A converter DC bus protection device, characterized in that: include: A switching module and a plurality of protection circuits with different functions, wherein the plurality of protection circuits are used to be connected between a DC bus and a DC load to protect the DC bus, and the switching module is used to switch the protection circuits connected between the DC bus and the DC load; The protection circuit comprises a first connection terminal, a second connection terminal, a third connection terminal and a fourth connection terminal respectively used to be connected to the positive connection terminal and the negative connection terminal of the DC bus, and the positive connection terminal and the negative connection terminal of the DC load; The switching module includes a rotating component for carrying the multiple protection circuits, the multiple protection circuits include a polarity reverse protection circuit and a residual charge discharge circuit connected between a DC bus and a DC load; four connection ends of the polarity reverse protection circuit and the residual charge discharge circuit are arranged at four corners of a square centered on the rotation axis of the rotating component; When the rotating component rotates to a set angle, the four connection terminals of the reverse polarity protection circuit or the residual charge discharge circuit are just connected to the positive connection terminal, the negative connection terminal of the DC bus, and the positive connection terminal and the negative connection terminal of the DC load.

2. The converter DC bus protection device according to claim 1, characterized in that: The switching module is used to control the connection and disconnection between the four connection terminals of the protection circuit and the positive connection terminal, the negative connection terminal of the DC bus, and the positive connection terminal, the negative connection terminal of the DC load.

3. The converter DC bus protection device according to claim 1, characterized in that: The switching module also includes a driving circuit, a stepper motor and a rotating shaft, wherein the rotating shaft is connected to the rotating component, the stepper motor is connected to the rotating shaft, and the driving circuit is connected to the stepper motor, and the driving circuit is used to drive the stepper motor to rotate so as to drive the rotating component to rotate.

4. The converter DC bus protection device according to claim 1, characterized in that: The reverse polarity protection circuit includes diodes D1, D2, D3, and D4. The first connection end of the reverse polarity protection circuit is respectively connected to the anode of the diode D1 and the cathode of the diode D3, the second connection end of the reverse polarity protection circuit is respectively connected to the cathode of the diode D1 and the cathode of the diode D4, the third connection end of the reverse polarity protection circuit is respectively connected to the anode of the diode D2 and the anode of the diode D3, and the fourth connection end of the reverse polarity protection circuit is respectively connected to the cathode of the diode D2 and the anode of the diode D4.

5. The converter DC bus protection device according to claim 4, characterized in that: The reverse polarity protection circuit also includes fuses FU1 and FU2. Fuse FU1 is connected between the cathode of diode D1 and the second connection terminal of the reverse polarity protection circuit, and fuse FU2 is connected between the anode of diode D4 and the fourth connection terminal of the reverse polarity protection circuit.

6. The converter DC bus protection device according to claim 1, characterized in that: The residual charge discharge circuit includes resistors R1, R2, R3, and R4. The resistors R1 and R2 are connected in series between the second connection terminal and the third connection terminal of the residual charge discharge circuit. The resistors R3 and R4 are connected in series between the first connection terminal and the fourth connection terminal of the residual charge discharge circuit.

7. The converter DC bus protection device according to claim 1, characterized in that: It also includes a control module connected to the switching module, and the control module is used to transmit the user's switching instruction to the switching module.

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