An ice melting device

Abstract

The present application provides an ice-melting device, relating to the field of circuit technology, comprising: a first multi-level rectifier bridge, wherein the input end of the first multi-level rectifier bridge is connected to an AC power source, a first output end of the first multi-level rectifier bridge is provided with a first switch, the first output end of the first multi-level rectifier bridge is used to connect to a first end of a transmission line via the first switch, and a second output end of the first multi-level rectifier bridge is used to connect to a second end of the transmission line; a second multi-level rectifier bridge, wherein the input end of the second multi-level rectifier bridge is connected to an AC power source, the first output end of the second multi-level rectifier bridge is used to connect to the first end of the transmission line, a second output end of the second multi-level rectifier bridge is provided with a second switch, and the second output end of the second multi-level rectifier bridge is used to connect to the second end of the transmission line via the second switch; and a third switch, wherein the first end of the first multi-level rectifier bridge and the second end of the second multi-level rectifier bridge are connected via the third switch. The present application can improve the ice-melting effect on transmission lines.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to an ice melting device. Background Art

[0002] Transmission lines may become covered in ice in winter. This ice can cause weight changes on the transmission lines, potentially leading to breakage and widespread power outages. A related technical document (CN104753015B) discloses a transmission line de-icing device comprising a transformer and a diode rectifier bridge, as well as a three-phase voltage source converter and AC output filter. The secondary winding of the transformer is connected to the three-phase AC output terminals of the three-phase voltage source converter and AC output filter and the three AC input terminals of the diode rectifier bridge. The three-phase voltage source converter and AC output filter primarily comprises a three-phase voltage source converter circuit and a three-phase filter circuit. These circuits are used to convert the three-phase voltage source and compensate for the harmonic currents generated by the diode rectifier bridge when the de-icing device is operating in de-icing mode. When not de-icing, the de-icing device operates in dynamic reactive power compensation to achieve de-icing of the power lines. However, there are lines with different cross-sectional sizes in the power grid, such as conductors and ground wires used to transmit electricity. The cross-sections of the two lines are quite different, and the required ice-melting voltages and ice-melting currents are different (for example, the conductor ice-melting voltage is smaller but the ice-melting current is larger, while the ground wire ice-melting voltage is larger but the ice-melting current is smaller). The output voltage in the relevant technical documents is low and cannot meet the ice-melting requirements of lines with different cross-sectional sizes, resulting in poor ice-melting effects on some lines.

[0003] It can be seen that the related art has the problem of poor ice melting effect on transmission lines. Summary of the Invention

[0004] An embodiment of the present application provides an ice melting device to solve the problem of poor ice melting effect on power transmission lines in the related art.

[0005] To achieve the above objectives, an embodiment of the present application provides an ice melting device, comprising:

[0006] a first multi-level rectifier bridge, wherein an input end of the first multi-level rectifier bridge is used to connect to an AC power supply, a first output end of the first multi-level rectifier bridge is provided with a first switch, the first output end of the first multi-level rectifier bridge is used to connect to a first end of a power transmission line through the first switch, and a second output end of the first multi-level rectifier bridge is used to connect to a second end of the power transmission line;

[0007] a second multi-level rectifier bridge, wherein an input end of the second multi-level rectifier bridge is used to connect to the AC power supply, a first output end of the second multi-level rectifier bridge is used to connect to the first end of the transmission line, a second output end of the second multi-level rectifier bridge is provided with a second switch, and the second output end of the second multi-level rectifier bridge is used to connect to the second end of the transmission line through the second switch;

[0008] a third switch, wherein the first end of the first multi-level rectifier bridge and the second end of the second multi-level rectifier bridge are connected via the third switch;

[0009] When the ice melting device is required to output a first voltage and a first current, the first switch and the second switch are closed, and the third switch is opened;

[0010] When the ice melting device is required to output a second voltage and a second current, the first switch and the second switch are opened, the third switch is closed, the second voltage is greater than the first voltage, and the second current is less than the first current.

[0011] In one embodiment, when the AC power supply is a three-phase power supply, the first multi-level rectifier bridge includes three first rectifier arms and three second rectifier arms, the input end of each first rectifier arm is respectively used to connect to different phases of the three-phase power supply, the output end of each first rectifier arm is connected to one end of the third switch, the output end of each first rectifier arm is used to connect to the first end of the transmission line through the first switch, the input end of each second rectifier arm is respectively used to connect to different phases of the three-phase power supply, and the output end of each second rectifier arm is used to connect to the second end of the transmission line;

[0012] When the AC power supply is a three-phase power supply, the second multi-level rectifier bridge includes three third rectifier arms and three fourth rectifier arms, the input end of each third rectifier arm is used to connect to different phases of the three-phase power supply, the output end of each third rectifier arm is used to connect to the first end of the transmission line, the input end of each fourth rectifier arm is used to connect to different phases of the three-phase power supply, the output end of each fourth rectifier arm is connected to the other end of the third switch, and the output end of each fourth rectifier arm is used to connect to the second end of the transmission line through the second switch.

[0013] In one embodiment, each of the first rectifier arms includes at least one switch module, each of the second rectifier arms includes at least one switch module, each of the third rectifier arms includes at least one switch module, and each of the fourth rectifier arms includes at least one switch module.

[0014] In one embodiment, when each of the first rectifier arms includes a switch module, an input end of the switch module is used to connect different phases of the three-phase power supply, and an output end of the switch module is connected to the first switch and the third switch; and / or,

[0015] In the case where each second rectifier arm includes a switch module, the input end of the switch module is used to connect different phases of the three-phase power supply, and the output end of the switch module is used to connect the second end of the transmission line; and / or,

[0016] In the case where each third rectifier arm includes a switch module, the input end of the switch module is used to connect different phases of the three-phase power supply, and the output end of the switch module is used to connect the first end of the transmission line; and / or,

[0017] In the case where each fourth rectifier arm includes a switch module, the input end of the switch module is used to connect different phases of the three-phase power supply, and the output end of the switch module is connected to the second switch and the third switch.

[0018] In one embodiment, when each first rectifier arm includes at least two switch modules, the at least two switch modules are connected in series, and input ends of the at least two switch modules connected in series are used to connect different phases of the three-phase power supply, and output ends of the at least two switch modules connected in series are connected to the first switch and the third switch; and / or,

[0019] In the case where each second rectifier arm includes at least two switch modules, the at least two switch modules are connected in series, and the input ends of the switch modules connected in series are used to connect different phases of the three-phase power supply, and the output ends of the switch modules connected in series are used to connect the second end of the transmission line; and / or,

[0020] In the case where each third rectifier arm includes at least two switch modules, the at least two switch modules are connected in series, and the input ends of the series-connected switch modules are used to connect different phases of the three-phase power supply, and the output ends of the series-connected switch modules are used to connect to the first end of the transmission line; and / or,

[0021] In the case where each fourth rectifier arm includes at least two switch modules, the at least two switch modules are connected in series, and the input ends of the switch modules connected in series are used to connect different phases of the three-phase power supply, and the output ends of the switch modules connected in series are connected to the second switch and the third switch.

[0022] In one embodiment, the switch module includes:

[0023] a first switching unit and a second switching unit, wherein the input end of the first switching unit is used to connect to different phases of the three-phase power supply or the output ends of other switch modules, the output end of the first switching unit is connected to the input end of the second switching unit, and the output end of the second switching unit is used to connect to the first end of the transmission line, the second end of the transmission line, the first switch, the second switch, the third switch or the input end of other switch modules;

[0024] a third switching unit and a fourth switching unit, wherein the input end of the third switching unit is used to connect to different phases in the three-phase power supply or the output ends of other switch modules, the output end of the third switching unit is connected to the input end of the fourth switching unit, and the output end of the fourth switching unit is used to connect to the first end of the transmission line, the second end of the transmission line, the first switch, the second switch, the third switch or the input ends of other switch modules;

[0025] a capacitor, wherein a first end of the capacitor is connected to the output end of the first switching unit, and a second end of the capacitor is connected to the output end of the third switching unit;

[0026] The first opening and closing unit, the second opening and closing unit, the third opening and closing unit, and the fourth opening and closing unit are used to convert alternating current into direct current by connecting and disconnecting.

[0027] In one embodiment, the first opening and closing unit, the second opening and closing unit, the third opening and closing unit, and the fourth opening and closing unit each include a switching tube and a diode, the emitter of the switching tube is connected to the anode of the diode to form an input end, and the collector of the switching tube is connected to the cathode of the diode to form an output end.

[0028] In one embodiment, the input end of each first rectifier arm is provided with a reactor, and the input end of each first rectifier arm is connected to different phases of the three-phase power supply through the reactor; and / or,

[0029] The input end of each second rectifier arm is provided with the reactor, and the input end of each second rectifier arm is connected to different phases of the three-phase power supply through the reactor; and / or,

[0030] The input end of each third rectifier arm is provided with the reactor, and the input end of each third rectifier arm is connected to different phases of the three-phase power supply through the reactor; and / or,

[0031] The input end of each fourth rectifier arm is provided with the reactor, and the input end of each fourth rectifier arm is connected to different phases of the three-phase power supply through the reactor.

[0032] In one embodiment, the ice melting device further comprises a transformer, wherein the transformer comprises a first winding, a second winding, and a third winding, wherein the first winding is a delta winding or a Y winding, the second winding is a delta winding or a Y winding, and the third winding is a delta winding or a Y winding;

[0033] The first winding is used to connect to the AC power supply, the second winding is used to connect to the input end of the first multi-level rectifier bridge, and the third winding is used to connect to the input end of the second multi-level rectifier bridge.

[0034] In one embodiment, the ice melting device further comprises:

[0035] a fourth switch, wherein a first end of the fourth switch is connected to the first output end of the first multi-level rectifier bridge and the first output end of the first multi-level rectifier bridge, and a second end of the fourth switch is used to connect to the first end of the transmission line;

[0036] A fifth switch, wherein a first end of the fifth switch is connected to the second output end of the first multi-level rectifier bridge and the second output end of the first multi-level rectifier bridge, and a second end of the fifth switch is used to connect to the second end of the transmission line.

[0037] One of the above technical solutions has the following advantages or beneficial effects:

[0038] In an embodiment of the present application, the ice melting device includes: a first multilevel rectifier bridge, wherein an input end of the first multilevel rectifier bridge is used to connect to an AC power source, a first output end of the first multilevel rectifier bridge is provided with a first switch, the first output end of the first multilevel rectifier bridge is used to connect to a first end of a transmission line through the first switch, and a second output end of the first multilevel rectifier bridge is used to connect to a second end of the transmission line; a second multilevel rectifier bridge, wherein an input end of the second multilevel rectifier bridge is used to connect to the AC power source, a first output end of the second multilevel rectifier bridge is used to connect to the first end of the transmission line, a second output end of the second multilevel rectifier bridge is provided with a second switch, and the second output end of the second multilevel rectifier bridge is used to connect to the second end of the transmission line through the second switch; and a third switch, wherein the first end of the first multilevel rectifier bridge and the second end of the second multilevel rectifier bridge are connected via the third switch. In this way, when the ice-melting device is required to output a first voltage and a first current, the first switch and the second switch are closed, and the third switch is opened; when the ice-melting device is required to output a second voltage and a second current, the first switch and the second switch are opened, and the third switch is closed, the second voltage is greater than the first voltage, and the second current is less than the first current. The first switch, the second switch, and the third switch are used to implement switching between series and parallel connection of the first multi-level rectifier bridge and the second multi-level rectifier bridge to output different voltages and currents, thereby adapting to different types of transmission lines and improving the ice-melting effect of the transmission lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0040] Figure 1 is a structural diagram of an ice melting device provided in an embodiment of the present application;

[0041] Figure 2 is a schematic diagram of a multi-level rectifier bridge in the related art;

[0042] Figure 3 This is a schematic diagram of the ice melting process provided by the embodiment of the present application;

[0043] Figure 4 This is a structural diagram of the switch module provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described 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 making creative efforts are within the scope of protection of this application.

[0045] See Figure 1 ,like Figure 1 As shown, an embodiment of the present application provides an ice melting device, comprising:

[0046] a first multi-level rectifier bridge, wherein an input end of the first multi-level rectifier bridge is used to connect to an AC power supply, a first output end of the first multi-level rectifier bridge is provided with a first switch K1, the first output end of the first multi-level rectifier bridge is used to connect to a first end of a transmission line through the first switch K1, and a second output end of the first multi-level rectifier bridge is used to connect to a second end of the transmission line;

[0047] a second multi-level rectifier bridge, wherein an input end of the second multi-level rectifier bridge is used to connect to the AC power supply, a first output end of the second multi-level rectifier bridge is used to connect to the first end of the transmission line, a second output end of the second multi-level rectifier bridge is provided with a second switch K2, and the second output end of the second multi-level rectifier bridge is used to connect to the second end of the transmission line through the second switch K2;

[0048] a third switch K3, wherein the second end of the first multi-level rectifier bridge is connected to the first end of the second multi-level rectifier bridge via the third switch K3;

[0049] When the ice melting device is required to output the first voltage and the first current, the first switch K1 and the second switch K2 are closed, and the third switch K3 is opened;

[0050] When the ice melting device is required to output a second voltage and a second current, the first switch K1 and the second switch K2 are opened, the third switch K3 is closed, the second voltage is greater than the first voltage, and the second current is less than the first current.

[0051] Both the first and second multilevel rectifier bridges can convert AC power from an AC power source into DC power. The first and second multilevel rectifier bridges include diodes D and switches S, which convert the AC power from the AC power source into DC power.

[0052] The voltage of the first multi-level rectifier bridge and the voltage of the second multi-level rectifier bridge may be the same or different.

[0053] The first switch K1, the second switch K2, and the third switch K3 are used to control the connection between the first and second multilevel rectifier bridges. To control the ice-melting device to output a lower voltage and a higher current (i.e., a first voltage and a first current), the first and second multilevel rectifier bridges need to be connected in parallel. In this case, the third switch K3 is disconnected, and the first and second switches K1, K2 are closed. To control the ice-melting device to output a higher voltage and a lower current (i.e., a second voltage and a second current), the first and second multilevel rectifier bridges need to be connected in series. In this case, the third switch K3 is closed, and the first and second switches K1, K2 are disconnected. The first, second, and third switches K1, K2, and K3 enable switching between the series and parallel connections of the first and second multilevel rectifier bridges to achieve different output voltages.

[0054] Optionally, the first switch K1 , the second switch K2 and the third switch K3 may be isolation switches.

[0055] It should be noted that, by connecting the first multi-level rectifier bridge and the second multi-level rectifier bridge in series or in parallel, Figure 2 The multi-level rectifier bridge shown (for example, only the first multi-level rectifier bridge) can provide different voltages and currents for ice melting, thereby flexibly adapting to different ice melting requirements of transmission lines.

[0056] For example, Figure 3 As shown, the present application provides a flowchart of ice melting by an ice melting device. When ice melting is required, the type of the transmission line is determined; when the transmission line is a conductor, it is determined to melt ice at a first voltage, and at this time, the first switch K1 and the second switch K2 are controlled to be closed, and the third switch K3 is controlled to be opened; when the transmission line is a ground line, it is determined to melt ice at a second voltage, and at this time, the first switch K1 and the second switch K2 are controlled to be opened, and the third switch K3 is controlled to be closed.

[0057] In an embodiment of the present application, the ice melting device includes: a first multilevel rectifier bridge, wherein an input end of the first multilevel rectifier bridge is used to connect to an AC power source, a first output end of the first multilevel rectifier bridge is provided with a first switch K1, the first output end of the first multilevel rectifier bridge is used to connect to a first end of a transmission line through the first switch K1, and a second output end of the first multilevel rectifier bridge is used to connect to a second end of the transmission line; a second multilevel rectifier bridge, wherein an input end of the second multilevel rectifier bridge is used to connect to the AC power source, a first output end of the second multilevel rectifier bridge is used to connect to the first end of the transmission line, a second output end of the second multilevel rectifier bridge is provided with a second switch K2, and the second output end of the second multilevel rectifier bridge is used to connect to the second end of the transmission line through the second switch K2; and a third switch, wherein the first end of the first multilevel rectifier bridge and the second end of the second multilevel rectifier bridge are connected via the third switch. In this way, when the ice-melting device is required to output a first voltage and a first current, the first switch K1 and the second switch K2 are closed, and the third switch K3 is opened. When the ice-melting device is required to output a second voltage and a second current, the first switch K1 and the second switch K2 are opened, and the third switch K3 is closed. The second voltage is greater than the first voltage, and the second current is less than the first current. The first switch K1, the second switch K2, and the third switch K3 implement switching between series and parallel connection of the first multi-level rectifier bridge and the second multi-level rectifier bridge to output different voltages and currents, thereby adapting to different types of transmission lines and improving the ice-melting effect of the transmission lines.

[0058] In one embodiment, when the AC power supply is a three-phase power supply, the first multi-level rectifier bridge includes three first rectifier arms U1 and three second rectifier arms U2, the input end of each first rectifier arm U1 is respectively used to connect to different phases of the three-phase power supply, the output end of each first rectifier arm U1 is connected to one end of the third switch K3, the output end of each first rectifier arm U1 is used to connect to the first end of the transmission line through the first switch K1, the input end of each second rectifier arm U2 is respectively used to connect to different phases of the three-phase power supply, and the output end of each second rectifier arm U2 is used to connect to the second end of the transmission line;

[0059] When the AC power supply is a three-phase power supply, the second multi-level rectifier bridge includes three third rectifier arms U3 and three fourth rectifier arms U4, the input end of each third rectifier arm U3 is used to connect to different phases of the three-phase power supply, the output end of each third rectifier arm U3 is used to connect to the first end of the transmission line, the input end of each fourth rectifier arm U4 is used to connect to different phases of the three-phase power supply, the output end of each fourth rectifier arm U4 is connected to the other end of the third switch K3, and the output end of each fourth rectifier arm U4 is used to connect to the second end of the transmission line through the second switch K2.

[0060] In an embodiment of the present application, the above-mentioned three first rectifier arms U1 are respectively connected to the three phases of the three-phase power supply, the above-mentioned three second rectifier arms U2 are respectively connected to the three phases of the three-phase power supply, the above-mentioned three third rectifier arms U3 are respectively connected to the three phases of the three-phase power supply, and the above-mentioned three fourth rectifier arms U4 are respectively connected to the three phases of the three-phase power supply, so as to provide AC voltage to each first rectifier arm U1, second rectifier arm U2, third rectifier arm U3 and fourth rectifier arm U4 through three power supplies, and each first rectifier arm U1, second rectifier arm U2, third rectifier arm U3 and fourth rectifier arm U4 converts AC power into DC power.

[0061] Among them, each first rectifier arm U1, second rectifier arm U2, third rectifier arm U3 and fourth rectifier arm U4 includes a switching module, which converts AC power into DC power through the switching module. Optionally, the switching module can be a modular multilevel converter (MMC) sub-module (SM), which converts AC power into DC power through the SM.

[0062] Specifically, each first rectifier arm U1 includes at least one switch module, each second rectifier arm U2 includes at least one switch module, each third rectifier arm U3 includes at least one switch module, and each fourth rectifier arm U4 includes at least one switch module.

[0063] In the embodiment of the present application, each switch module is configured to output a positive voltage level, a negative voltage level, or a zero voltage level. By controlling the on and off states of each switch module, conversion between AC and DC is achieved. Furthermore, by providing different numbers of switch modules in each of the first rectifier arm U1, the second rectifier arm U2, the third rectifier arm U3, and the fourth rectifier arm U4, each of the first rectifier arm U1, the second rectifier arm U2, the third rectifier arm U3, and the fourth rectifier arm U4 can output different voltages, thereby increasing the flexibility of the ice-melting device.

[0064] Each of the first rectifier arm U1, the second rectifier arm U2, the third rectifier arm U3, and the fourth rectifier arm U4 includes at least one switch module. The voltage of the switch module is fixed. The number of switch modules in each of the first rectifier arm U1, the second rectifier arm U2, the third rectifier arm U3, and the fourth rectifier arm U4 can be determined based on the required output voltages of the first multi-level rectifier bridge and the second multi-level rectifier bridge. For example, if the first rectifier arm U1 needs to output a voltage of -6kV to 6kV and the voltage of each switch module is -2kV to 2kV, then three switch modules are provided in the first rectifier arm U1.

[0065] In one embodiment, when each first rectifier arm U1 includes a switch module, the input end of the switch module is used to connect different phases of the three-phase power supply, and the output end of the switch module is connected to the first switch K1 and the third switch K3; and / or,

[0066] In the case where each second rectifier arm U2 includes a switch module, the input end of the switch module is used to connect different phases of the three-phase power supply, and the output end of the switch module is used to connect the second end of the transmission line; and / or,

[0067] In the case where each third rectifier arm U3 includes a switch module, the input end of the switch module is used to connect different phases of the three-phase power supply, and the output end of the switch module is used to connect the first end of the transmission line; and / or,

[0068] When each fourth rectifier arm U4 includes a switch module, the input end of the switch module is used to connect different phases of the three-phase power supply, and the output end of the switch module is connected to the second switch K2 and the third switch K3.

[0069] In an embodiment of the present application, when each first rectifier arm U1, each second rectifier arm U2, each third rectifier arm U3 or each fourth rectifier arm U4 includes only one switch module, the switch module is directly used to connect different phases in the three-phase power supply and the first end, the second end, the first switch K1, the second switch K2 or the third switch K3 of the transmission line, thereby enabling each first rectifier arm U1, each second rectifier arm U2, each third rectifier arm U3 or each fourth rectifier arm U4 to convert alternating current into direct current.

[0070] In one embodiment, when each first rectifier arm U1 includes at least two switch modules, the at least two switch modules are connected in series, and the input ends of the at least two switch modules connected in series are used to connect different phases of the three-phase power supply, and the output ends of the at least two switch modules connected in series are connected to the first switch K1 and the third switch K3; and / or,

[0071] In the case where each second rectifier arm U2 includes at least two switch modules, the at least two switch modules are connected in series, and the input ends of the series-connected switch modules are used to connect different phases of the three-phase power supply, and the output ends of the series-connected switch modules are used to connect the second end of the transmission line; and / or,

[0072] In the case where each third rectifier arm U3 includes at least two switch modules, the at least two switch modules are connected in series, and the input ends of the switch modules connected in series are used to connect different phases of the three-phase power supply, and the output ends of the switch modules connected in series are used to connect the first end of the transmission line; and / or,

[0073] When each fourth rectifier arm U4 includes at least two switch modules, the at least two switch modules are connected in series, and the input ends of the switch modules connected in series are used to connect different phases of the three-phase power supply, and the output ends of the switch modules connected in series are connected to the second switch K2 and the third switch K3.

[0074] In an embodiment of the present application, when each first rectifier arm U1, each second rectifier arm U2, each third rectifier arm U3 or each fourth rectifier arm includes at least two switch modules, it is necessary to first connect at least two switch modules in series, and then connect the switch modules in series to different phases of the three-phase power supply and the first end, the second end, the first switch K1, the second switch K2 or the third switch K3 of the transmission line, so as to enable each first rectifier arm U1, each second rectifier arm U2, each third rectifier arm U3 or each fourth rectifier arm U4 to convert alternating current into direct current.

[0075] In which, when at least two switch modules are connected in series, two adjacent switch modules are connected to the output end of the other switch module through the input end of one switch module, and at least two switch modules connected in series have only one unconnected first end and second end, which are connected to different phases of the three-phase power supply and the first end, second end, first switch K1, second switch K2 or third switch K3 of the transmission line through the unconnected first end and second end.

[0076] In one embodiment, Figure 4 As shown, the switch module includes:

[0077] a first switching unit and a second switching unit, wherein the input end of the first switching unit is used to connect to different phases of the three-phase power supply or the output ends of other switch modules, the output end of the first switching unit is connected to the input end of the second switching unit, and the output end of the second switching unit is used to connect to the first end of the transmission line, the second end of the transmission line, the first switch K1, the second switch K2, the third switch K3, or the input ends of other switch modules;

[0078] a third switching unit and a fourth switching unit, wherein the input end of the third switching unit is used to connect to different phases in the three-phase power supply or the output ends of other switch modules, the output end of the third switching unit is connected to the input end of the fourth switching unit, and the output end of the fourth switching unit is used to connect to the first end of the transmission line, the second end of the transmission line, the first switch K1, the second switch K2, the third switch K3, or the input ends of other switch modules;

[0079] a capacitor C, wherein a first end of the capacitor C is connected to the output end of the first switching unit, and a second end of the capacitor C is connected to the output end of the third switching unit;

[0080] The first opening and closing unit, the second opening and closing unit, the third opening and closing unit, and the fourth opening and closing unit are used to convert alternating current into direct current by connecting and disconnecting.

[0081] The first, second, third, and fourth switching units, along with capacitor C, work together to convert alternating current (AC) into direct current (DC). Capacitor C provides voltage when the first, second, third, and fourth switching units are connected or disconnected.

[0082] In an embodiment of the present application, the switch module includes: a first switching unit and a second switching unit, wherein the input end of the first switching unit is used to connect to different phases in a three-phase power supply or the output end of another switching module, the output end of the first switching unit is connected to the input end of the second switching unit, and the output end of the second switching unit is used to connect to the first end of the transmission line, the second end of the transmission line, the first switch K1, the second switch K2, the third switch K3, or the input end of another switching module; a third switching unit and a fourth switching unit, wherein the input end of the third switching unit is used to connect to different phases in a three-phase power supply or the output end of another switching module, the output end of the third switching unit is connected to the input end of the fourth switching unit, and the output end of the fourth switching unit is used to connect to the first end of the transmission line, the second end of the transmission line, the first switch K1, the second switch K2, the third switch K3, or the input end of another switching module; and a capacitor C, wherein the first end of the capacitor C is connected to the output end of the first switching unit and the second end of the capacitor C is connected to the output end of the third switching unit. In this way, the first, second, third, and fourth switching units are connected and disconnected to achieve conversion of AC power into DC power.

[0083] In one embodiment, the first opening and closing unit, the second opening and closing unit, the third opening and closing unit, and the fourth opening and closing unit each include a switch tube S and a diode D, the emitter of the switch tube S is connected to the anode of the diode D to form an input end, and the collector of the switch tube S is connected to the cathode of the diode D to form an output end.

[0084] In the embodiment of the present application, by connecting the switch tube S and the diode D in parallel, when AC power is connected, the switch tube S and the diode D can convert AC power into DC power, and can effectively compensate for harmonics, thereby reducing the harmonics of the ice melting device.

[0085] The switch tube S may be an insulated gate bipolar transistor (IGBT), an integrated gate-commutated thyristor (IGCT) or a field effect transistor.

[0086] In one embodiment, the input end of each first rectifier arm U1 is provided with a reactor L, and the input end of each first rectifier arm U1 is connected to different phases of the three-phase power supply through the reactor L; and / or,

[0087] The input end of each second rectifier arm U2 is provided with the reactor L, and the input end of each second rectifier arm U2 is connected to different phases of the three-phase power supply through the reactor L; and / or,

[0088] The input end of each third rectifier arm U3 is provided with the reactor L, and the input end of each third rectifier arm U3 is connected to different phases of the three-phase power supply through the reactor L; and / or,

[0089] The input end of each fourth rectifier arm U4 is provided with the reactor L, and the input end of each fourth rectifier arm U4 is connected to different phases of the three-phase power supply through the reactor L.

[0090] It should be noted that circulating current will be generated in the process of converting AC power into DC power through the first multi-level rectifier bridge and / or the second multi-level rectifier bridge. In order to reduce the circulating current of the ice melting device, in the embodiment of the present application, the input end of each first rectifier arm U1 is connected to different phases of the three-phase power supply through the reactor L; and / or, the input end of each second rectifier arm U2 is provided with the reactor L, and the input end of each second rectifier arm U2 is connected to different phases of the three-phase power supply through the reactor L; and / or, each third rectifier arm U2 is connected to different phases of the three-phase power supply through the reactor L. The input end of the rectifier arm U3 is provided with the reactor L, and the input end of each third rectifier arm U3 is connected to different phases of the three-phase power supply through the reactor L; and / or, the input end of each fourth rectifier arm U4 is provided with the reactor L, and the input end of each fourth rectifier arm U4 is connected to different phases of the three-phase power supply through the reactor L, and the circulating current of the first rectifier arm U1, the second rectifier arm U2, the third rectifier arm U3 and / or the fourth rectifier arm U4 is reduced by the reactor L, thereby reducing the circulating current of the transmission line de-icing device.

[0091] In one embodiment, the ice melting device further includes a transformer T, wherein the transformer T includes a first winding, a second winding, and a third winding, wherein the first winding is a delta winding or a Y winding, the second winding is a delta winding or a Y winding, and the third winding is a delta winding or a Y winding;

[0092] The first winding is used to connect to the AC power supply, the second winding is used to connect to the input end of the first multi-level rectifier bridge, and the third winding is used to connect to the input end of the second multi-level rectifier bridge.

[0093] The transformer T is used to control the voltage of the AC power input to the first multilevel rectifier bridge and the second multilevel rectifier bridge. The transformer T includes a first winding, a second winding, and a third winding, which are used to be connected to an AC power source, the first multilevel rectifier bridge, and the second multilevel rectifier bridge, respectively, and input the transformed AC power to the first multilevel rectifier bridge and the second multilevel rectifier bridge through the first winding, the second winding, and the third winding.

[0094] The first winding, the second winding, and the third winding can be delta windings or Y-shaped windings. The second winding is used to connect to the input of the first multi-level rectifier bridge, and the third winding is used to connect to the input of the second multi-level rectifier bridge. Power is supplied to the first multi-level rectifier bridge via the second winding, and power is supplied to the second multi-level rectifier bridge via the third winding. The second and third windings output the same voltage.

[0095] In an embodiment of the present application, the ice-melting device further includes a transformer T, which includes a first winding, a second winding, and a third winding. The first winding is a delta winding or a Y-shaped winding, the second winding is a delta winding or a Y-shaped winding, and the third winding is a delta winding or a Y-shaped winding. The first winding is used to connect to an AC power source, the second winding is used to connect to the input of a first multi-level rectifier bridge, and the third winding is used to connect to the input of a second multi-level rectifier bridge. In this way, the transformed AC power is input to the first and second multi-level rectifier bridges via the first, second, and third windings, thereby achieving voltage control of the input AC power.

[0096] In one embodiment, the ice melting device further comprises:

[0097] a fourth switch K4, wherein a first end of the fourth switch K4 is connected to the first output end of the first multi-level rectifier bridge and the first output end of the first multi-level rectifier bridge, and a second end of the fourth switch K4 is used to connect to the first end of the transmission line;

[0098] A fifth switch K5 , wherein a first end of the fifth switch K5 is connected to the second output end of the first multi-level rectifier bridge and the second output end of the first multi-level rectifier bridge, and a second end of the fifth switch K5 is used to connect to the second end of the transmission line.

[0099] The first multi-level rectifier bridge and the second multi-level rectifier bridge both include capacitors. Dynamic reactive power compensation for the AC power supply can be achieved through the capacitors included in the first multi-level rectifier bridge and the second multi-level rectifier bridge.

[0100] Specifically, when dynamic reactive power compensation is required by the ice melting device, the ice melting device is not connected to the transmission line, the fourth switch K4 and the fifth switch K5 are disconnected, and dynamic reactive power compensation of the AC power supply is achieved by the capacitors included in the first multi-level rectifier bridge and the second multi-level rectifier bridge.

[0101] In the embodiment of the present application, the ice-melting device further includes a fourth switch K4, a first end of the fourth switch K4 being connected to the first output end of the first multi-level rectifier bridge and the first output end of the first multi-level rectifier bridge, and a second end of the fourth switch K4 being used to connect to the first end of the transmission line; and a fifth switch K5, a first end of the fifth switch K5 being connected to the second output end of the first multi-level rectifier bridge and the second output end of the first multi-level rectifier bridge, and a second end of the fifth switch K5 being used to connect to the second end of the transmission line. By disconnecting the fourth switch K4 and the fifth switch K5, the first multi-level rectifier bridge and the second multi-level rectifier bridge are connected to the AC power supply, so that the ice-melting device can melt ice on the transmission line and achieve dynamic reactive power compensation for the AC power supply.

[0102] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0103] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

Claims

1. An ice melting device, characterized in that: include: a first multi-level rectifier bridge, wherein an input end of the first multi-level rectifier bridge is used to connect to an AC power supply, a first output end of the first multi-level rectifier bridge is provided with a first switch, the first output end of the first multi-level rectifier bridge is used to connect to a first end of a power transmission line through the first switch, and a second output end of the first multi-level rectifier bridge is used to connect to a second end of the power transmission line; a second multi-level rectifier bridge, wherein an input end of the second multi-level rectifier bridge is used to connect to the AC power supply, a first output end of the second multi-level rectifier bridge is used to connect to the first end of the transmission line, a second output end of the second multi-level rectifier bridge is provided with a second switch, and the second output end of the second multi-level rectifier bridge is used to connect to the second end of the transmission line through the second switch; a third switch, wherein the first end of the first multi-level rectifier bridge and the second end of the second multi-level rectifier bridge are connected via the third switch; When the power transmission line is a conductor and the ice melting device is required to output a first voltage and a first current, the first switch and the second switch are closed, and the third switch is opened; When the power transmission line is a ground line and the ice melting device is required to output a second voltage and a second current, the first switch and the second switch are opened, the third switch is closed, the second voltage is greater than the first voltage, and the second current is less than the first current; In the case where the AC power supply is a three-phase power supply, the first multi-level rectifier bridge includes three first rectifier arms and three second rectifier arms, the input end of each first rectifier arm is respectively used to connect to different phases of the three-phase power supply, the output end of each first rectifier arm is connected to one end of the third switch, the output end of each first rectifier arm is used to connect to the first end of the transmission line through the first switch, the input end of each second rectifier arm is respectively used to connect to different phases of the three-phase power supply, and the output end of each second rectifier arm is used to connect to the second end of the transmission line; When the AC power supply is a three-phase power supply, the second multi-level rectifier bridge includes three third rectifier arms and three fourth rectifier arms, the input end of each third rectifier arm is respectively used to connect to different phases of the three-phase power supply, the output end of each third rectifier arm is used to connect to the first end of the transmission line, the input end of each fourth rectifier arm is respectively used to connect to different phases of the three-phase power supply, the output end of each fourth rectifier arm is connected to the other end of the third switch, and the output end of each fourth rectifier arm is used to connect to the second end of the transmission line through the second switch; Each of the first rectifier arms includes at least one switch module, each of the second rectifier arms includes at least one switch module, each of the third rectifier arms includes at least one switch module, and each of the fourth rectifier arms includes at least one switch module; In which, the voltage of the switching module is fixed, the number of the switching modules in each first rectifier arm, each second rectifier arm, each third rectifier arm and each fourth rectifier arm is confirmed based on the voltage required to be output by the first multi-level rectifier bridge and the second multi-level rectifier bridge, and the voltage of each switching module is -2kV to 2kV.

2. The ice melting device according to claim 1, wherein: In the case where each first rectifier arm includes a switch module, an input end of the switch module is used to connect different phases of the three-phase power supply, and an output end of the switch module is connected to the first switch and the third switch; and / or, In the case where each second rectifier arm includes a switch module, the input end of the switch module is used to connect different phases of the three-phase power supply, and the output end of the switch module is used to connect the second end of the transmission line; and / or, In the case where each third rectifier arm includes a switch module, the input end of the switch module is used to connect different phases of the three-phase power supply, and the output end of the switch module is used to connect the first end of the transmission line; and / or, In the case where each fourth rectifier arm includes a switch module, the input end of the switch module is used to connect different phases of the three-phase power supply, and the output end of the switch module is connected to the second switch and the third switch.

3. The ice melting device according to claim 1, wherein: In the case where each first rectifier arm includes at least two switch modules, the at least two switch modules are connected in series, and input ends of the at least two switch modules connected in series are used to connect different phases of the three-phase power supply, and output ends of the at least two switch modules connected in series are connected to the first switch and the third switch; and / or In the case where each second rectifier arm includes at least two switch modules, the at least two switch modules are connected in series, and the input ends of the switch modules connected in series are used to connect different phases of the three-phase power supply, and the output ends of the switch modules connected in series are used to connect the second end of the transmission line; and / or, In the case where each third rectifier arm includes at least two switch modules, the at least two switch modules are connected in series, and the input ends of the series-connected switch modules are used to connect different phases of the three-phase power supply, and the output ends of the series-connected switch modules are used to connect to the first end of the transmission line; and / or, In the case where each fourth rectifier arm includes at least two switch modules, the at least two switch modules are connected in series, and the input ends of the switch modules connected in series are used to connect different phases of the three-phase power supply, and the output ends of the switch modules connected in series are connected to the second switch and the third switch.

4. The ice melting device according to claim 1, wherein: The switch module includes: a first switching unit and a second switching unit, wherein the input end of the first switching unit is used to connect to different phases of the three-phase power supply or the output ends of other switch modules, the output end of the first switching unit is connected to the input end of the second switching unit, and the output end of the second switching unit is used to connect to the first end of the transmission line, the second end of the transmission line, the first switch, the second switch, the third switch or the input end of other switch modules; a third switching unit and a fourth switching unit, wherein the input end of the third switching unit is used to connect to different phases in the three-phase power supply or the output ends of other switch modules, the output end of the third switching unit is connected to the input end of the fourth switching unit, and the output end of the fourth switching unit is used to connect to the first end of the transmission line, the second end of the transmission line, the first switch, the second switch, the third switch or the input ends of other switch modules; a capacitor, wherein a first end of the capacitor is connected to the output end of the first switching unit, and a second end of the capacitor is connected to the output end of the third switching unit; The first opening and closing unit, the second opening and closing unit, the third opening and closing unit, and the fourth opening and closing unit are used to convert alternating current into direct current by connecting and disconnecting.

5. The ice melting device according to claim 4, characterized in that: The first opening and closing unit, the second opening and closing unit, the third opening and closing unit and the fourth opening and closing unit all include a switching tube and a diode, the emitter of the switching tube is connected to the anode of the diode to form an input end, and the collector of the switching tube is connected to the cathode of the diode to form an output end.

6. The ice melting device according to claim 1, wherein: The input end of each first rectifier arm is provided with a reactor, and the input end of each first rectifier arm is connected to different phases of the three-phase power supply through the reactor; and / or, The input end of each second rectifier arm is provided with the reactor, and the input end of each second rectifier arm is connected to different phases of the three-phase power supply through the reactor; and / or, The input end of each third rectifier arm is provided with the reactor, and the input end of each third rectifier arm is connected to different phases of the three-phase power supply through the reactor; and / or, The input end of each fourth rectifier arm is provided with the reactor, and the input end of each fourth rectifier arm is connected to different phases of the three-phase power supply through the reactor.

7. The ice melting device according to any one of claims 1 to 6, characterized in that: Also included is a transformer, the transformer including a first winding, a second winding and a third winding, the first winding being a delta winding or a Y-type winding, the second winding being a delta winding or a Y-type winding, and the third winding being a delta winding or a Y-type winding; The first winding is used to connect to the AC power supply, the second winding is used to connect to the input end of the first multi-level rectifier bridge, and the third winding is used to connect to the input end of the second multi-level rectifier bridge.

8. The ice melting device according to any one of claims 1 to 6, characterized in that: Also includes: a fourth switch, wherein a first end of the fourth switch is connected to the first output end of the first multi-level rectifier bridge and the first output end of the first multi-level rectifier bridge, and a second end of the fourth switch is used to connect to the first end of the transmission line; A fifth switch, wherein a first end of the fifth switch is connected to the second output end of the first multi-level rectifier bridge and the second output end of the first multi-level rectifier bridge, and a second end of the fifth switch is used to connect to the second end of the transmission line.

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