Switching device for a converter

Abstract

The present disclosure relates to a switching device for a converter (1) comprising: a first series connection (SC1) of at least two switches between two terminals of the switching device, wherein the two switches are semiconductor switches; a second series connection of a first capacitor (C1) and a first diode circuit (D1) electrically connected in parallel with a first part (P1) of the first series connection between a first terminal (T1) of the two terminals (T1, T2) and a node (Nc) between the two switches (SR1, SL1), wherein the first diode circuit comprises at least one diode (D11); and a third series connection of a second capacitor (C2) and a second diode circuit (D2) electrically connected in parallel with a second part (P2) of the first series connection between a second terminal (T2) of the two terminals and the node between the two switches, wherein the second diode circuit comprises at least one diode (D21). Furthermore, a method for switching the switching device between a conducting state and a non-conducting state.

Description

Technical Field

[0001] This disclosure relates to a switching device for a converter, a method for switching the switching device between an on state and an off state, and a converter system having at least one converter including at least one switching device. Background Technology

[0002] Medium / high voltage semiconductor switches are critical electrical components in power electronic converters, enabling increased power output without the need for complex multilevel converter topologies using low-voltage devices. However, the availability of such medium / high voltage semiconductor switches is limited. Summary of the Invention

[0003] The embodiments of the present invention are based on the following considerations of the inventors:

[0004] To achieve the functionality of medium / high voltage semiconductor switches, lower voltage-level semiconductor switches connected in series can be utilized. This technology can be used to implement unidirectional and bidirectional semiconductor switches for use in medium and high voltage power electronics applications. Semiconductor switches can also be referred to as directional control switches (DCS). The terms "connection" and "electrical connection" can be used synonymously.

[0005] A bidirectional semiconductor switch is used to control current flow in two directions. Therefore, a bidirectional semiconductor switch can also be called a bidirectional control switch (BCS). A bidirectional semiconductor switch can be implemented by one or more controlled semiconductor switches and optionally one or more diodes. The term "uncontrolled semiconductor switch" can be used as a synonym for the term "diode." The term "controlled semiconductor switch" can refer to a semiconductor switch that includes control terminals, such as transistors, thyristors, three-terminal bidirectional thyristor switches, etc. Specifically, the one or more controlled semiconductor switches of a bidirectional semiconductor switch can be one or more transistors, such as one or more insulated-gate bipolar transistors (IGBTs), one or more field-effect transistors (FETs), one or more metal-oxide-semiconductor field-effect transistors (MOSFETs), one or more bipolar junction transistors (BJTs), and / or one or more junction-gate field-effect transistors (JFETs). The term "diode" can refer to a semiconductor switch (without a control terminal) that allows current to flow in only one direction, such as pn semiconductor diodes, pin diodes, Schottky diodes, and intrinsic body diodes of the corresponding devices / transistors.

[0006] Examples of bidirectional semiconductor switches include anti-series (back-to-back) bidirectional semiconductor switches with common emitter or common collector, bidirectional semiconductor switches with diode bridges, and bidirectional semiconductor switches using reverse blocking IGBTs (RB-IGBTs). Figure 1 An example of this is shown.

[0007] A unidirectional semiconductor switch is used to control the flow of current in only one direction. Therefore, a unidirectional semiconductor switch can also be called a unidirectional control switch (UCS). Examples of unidirectional semiconductor switches are MOSFETs or IGBTs connected in series with a diode. Figure 1 An example of this is shown.

[0008] Existing technologies for semiconductor switches, such as Figure 1The switch shown, when used as a power switch in a converter, has significant limitations on the maximum breakdown voltage that existing devices can achieve. As mentioned above, to achieve a higher voltage level switch (i.e., a switch robust to higher voltage levels and therefore capable of operating at higher voltage levels), several low-voltage semiconductor switches (i.e., lower voltage level semiconductor switches) can be connected in series. The switch achieved by the series connection of low-voltage semiconductor switches corresponds to a higher voltage level switch compared to the voltage level applicable to each low-voltage semiconductor switch.

[0009] To switch a system comprised of multiple series-connected low-voltage semiconductor switches simultaneously, appropriate dynamic voltage sharing across the low-voltage semiconductor switches is achieved through existing device matching. Additionally, a buffer circuit is required, connected in parallel with each low-voltage semiconductor switch. The buffer circuit suppresses voltage transients when the low-voltage semiconductor switches switch together between on and off states. Precise tuning of the buffer circuit is also necessary to achieve proper dynamic sharing among the low-voltage semiconductor switches. Furthermore, the gate controllers of these semiconductor switches require gate driver level matching.

[0010] The precise tuning of existing device matching and snubber circuits for low-voltage semiconductor switches significantly increases the cost, complexity, and size of implementing medium / high power switching via series connection of low-voltage semiconductor switches. Furthermore, these snubbers introduce additional losses. Therefore, in high-voltage applications, these snubber circuits tend to be bulky and require meticulous cooling, which increases system size and reduces efficiency.

[0011] In view of the above-mentioned problems and disadvantages, embodiments of this disclosure aim to improve a switching device comprising a series connection of semiconductor switches for implementing switching, particularly switches used in converters. One object is to provide a switching device that overcomes the above-mentioned problems and disadvantages.

[0012] This objective is achieved through embodiments of the invention described in the appended independent claims. Advantageous implementations of the embodiments of the invention are further defined in the dependent claims.

[0013] A first aspect of this disclosure provides a switching device for a converter. The switching device includes a first series connection of at least two switches between two terminals of the switching device. The switching device further includes a second series connection of a first capacitor and a first diode circuit, the second series connection being electrically connected in parallel to a first portion of the first series connection between the first terminals of the two terminals and the node between the two switches, wherein the first diode circuit includes at least one diode. The switching device further includes a third series connection of a second capacitor and a second diode circuit, the third series connection being electrically connected in parallel to a second portion of the first series connection between the second terminals of the two terminals and the node between the two switches, wherein the second diode circuit includes at least one diode.

[0014] The first diode circuit, the first capacitor, the second diode circuit, and the second capacitor allow for individual switching of at least two switches connected in series. As a result, no existing device matching is required for the at least two switches connected in series. When the at least two switches are in a non-conducting state, the first and second capacitors, which can be charged via the first and second diode circuits, allow the voltage between the two terminals of the switching device to be shared equally by the at least two switches connected in series. Since the first and second capacitors are used for an intermediate voltage lower than the voltage between the two terminals of the switching device, and the first and second diode circuits provide a current path for the charging current used only to charge the first and second capacitors, the dimensions of the first and second capacitors, as well as the first and second diode circuits, are suitable for smaller voltage levels compared to the electrical components of a snubber circuit not required by the switching device of the first aspect. Therefore, compared to circuits including snubber circuits, especially in high-voltage applications, the switching device is smaller and does not require sophisticated cooling. Furthermore, the switching device according to the first aspect does not require existing device matching with the first series-connected switches, nor does it require precise tuning of the snubber circuit, which are not required by the switching device of the first aspect. This significantly reduces the cost, complexity, and size of implementing medium / high power switching using the switching device of the first aspect. Based on the above, the switching device of the first aspect overcomes the aforementioned problems and shortcomings.

[0015] Because the switching device used to implement the first aspect is smaller in size compared to a circuit using a buffer circuit, the switching device can be used for high-switching operations, i.e., switches for implementing high-switching operations. In other words, the compact design results in lower switching losses and faster switching times for the at least two switches connected in series in the first aspect.

[0016] Furthermore, using at least two switches connected in series in the first series connection, instead of a single semiconductor switch, allows for the use of switches suitable for lower voltage levels. That is, the blocking voltage of each switch in the first series connection can be lower than the blocking voltage of a single semiconductor switch. This reduces cost and conduction losses. The conduction losses of the switch increase with increasing blocking voltage because the resistance of the switch in the on state increases with increasing blocking voltage (e.g., resistance Rα (V)). 阻断 ) 2.5 ).

[0017] The switching device can be used to implement both the semiconductor switch and the power switch of the converter. Specifically, the switching device can be used to implement a unidirectional semiconductor switch or a bidirectional semiconductor switch. In particular, the switching device can be used to implement a solid-state switch with bidirectional control.

[0018] The terms “power converter” or “power electronic converter” can be used as synonyms for the term “converter”.

[0019] The switching device can be used in AC / DC converters, DC / AC converters, DC / DC converters, and AC / AC converters. In particular, the switching device can be used in T-type converters, such as 3-stage T-type converters; nested T-type converters, such as 3-stage or 5-stage nested T-type converters; monkey head converters; Vienna converters / rectifiers; and matrix converters. The switching device can also be used in other power electronic converter topologies known to those skilled in the art.

[0020] Specifically, the switching device can be used to implement at least one bidirectional semiconductor switch arranged in a T-type converter or Vienna converter / rectifier for connecting the neutral point supplied by two DC link capacitors arranged at the output of the T-type converter or Vienna rectifier.

[0021] Switching devices can be referred to by the term semiconductor switching device.

[0022] In the implementation of the first aspect, the switches of the switching device (i.e., at least two switches) are bidirectional semiconductor switches. This could be a case where the bidirectional semiconductor switch is implemented by a switching device.

[0023] In the implementation of the first aspect, at least one switch in the switching device (i.e., at least one of at least two switches) is a unidirectional semiconductor switch. Specifically, the switches (i.e., at least two switches) of the switching device can be unidirectional semiconductor switches. This can be a case where a unidirectional semiconductor switch is implemented using a switching device.

[0024] In other words, the first series connection includes an even number of switches, which is two or more. That is, the even number of switches can be two, four, six, eight, etc. In other words, the first series connection can include two switches, four switches, six switches, eight switches, etc.

[0025] In other words, the second series connection is electrically connected in parallel to the first portion of the first series connection between the first terminal and the node at the center of the first series connection, which is the central node of the first series connection; and the third series connection is electrically connected in parallel to the second portion of the first series connection between the second terminal and the central node of the first series connection. In the case where the first series connection includes two switches, the node between the two switches is the central node of the first series connection. The terms "central node" and "center node" can be used synonymously.

[0026] The node at the center (between two electrical components) of a series connection of an even number of electrical components is a node between two electrical components that is equidistant from both ends of the series connection in terms of node position. "In terms of node position" should be understood as "in terms of the number of nodes". The node at the center of a series connection of an even number of electrical components can also be called the center node of the series connection. In other words, the center node of a series connection of electrical components corresponds to a node between two electrical components, arranged such that the number of nodes between the center node and the first end of the series connection is equal to the number of nodes between the center node and the second end of the series connection. Therefore, in the case of a first series connection, the center node of the first series connection is the node between the two switches in the first series connection, arranged such that the number of nodes between the center node and the first terminal is equal to the number of nodes between the center node and the second terminal. In the case of only two switches, the number of nodes is zero.

[0027] A first diode circuit can be connected to a first terminal, and a first capacitor can be connected to a node between the two switches. Alternatively, a first capacitor can be connected to a first terminal, and a first diode circuit can be connected to a node between the two switches. A second diode circuit can be connected to a second terminal, and a second capacitor can be connected to a node between the two switches. Alternatively, a second capacitor can be connected to a second terminal, and a second diode circuit can be connected to a node between the two switches.

[0028] At least two switches can be connected in series between two terminals, such that when both switches are in the ON state, the two switches allow unidirectional current flow from the first terminal to the second terminal.

[0029] At least one diode in the first diode circuit can be arranged to be electrically connected in the second series connection, such that the at least one diode in the first diode circuit allows unidirectional current flow of charging current from the first terminal to the node between the two switches in the first series connection. Specifically, at least one diode in the first diode circuit can be arranged such that its anode is electrically connected to the first terminal or its cathode is electrically connected to the node between the two switches in the first series connection. In other words, at least one diode in the first diode circuit can be arranged to be electrically connected in the second series connection, such that its cathode points towards the node between the two switches in the first series connection.

[0030] When a diode in an electrical component is arranged in series at any point in the series connection, and its cathode points towards a node in the series connection, such as one end of the series connection (the end node), it should be understood that the diode is arranged in the series connection such that the cathode of the diode is shown as the direction of entry into the node. Therefore, when the diode is connected to a node, the cathode of the diode is connected to the node. Correspondingly, when a diode is arranged in a series connection such that its anode points towards the node, it should be understood that the diode is arranged in the series connection such that the anode of the diode is shown as the direction of entry into the node. Therefore, when the diode is connected to a node, the anode of the diode is connected to the node.

[0031] At least one diode in the second diode circuit can be arranged to be electrically connected in the third series connection, such that the at least one diode in the second diode circuit allows unidirectional current flow from the node between the two switches in the first series connection to the second terminal. Specifically, at least one diode in the second diode circuit can be arranged such that its cathode is electrically connected to the second terminal or its anode is electrically connected to the node between the two switches in the first series connection. In other words, at least one diode in the second diode circuit can be arranged to be electrically connected in the third series connection, such that its anode points towards the node between the two switches in the first series connection.

[0032] In one implementation of the first aspect, the first series connection comprises an even number of switches, greater than or equal to four, wherein the switches are semiconductor switches. The second and third series connections may each be electrically connected to a node at the center of the first series connection, the node being the central node of the first series connection. A first capacitor in the second series connection and a second capacitor in the third series connection may be electrically connected to the central node of the first series connection. The first and second diode circuits may each comprise a number of diodes equal to half the even number of the switches; and each diode in the first and second diode circuits may be connected in series with each other.

[0033] The more switches connected in the first series, the lower the applicable voltage level for each switch. In other words, the more switches connected in the first series, the lower the blocking voltage of each switch. This reduces cost and conduction losses. As mentioned above, since existing device matching for the switches in the first series is not required, a larger number of switches does not increase the complexity of implementing the switching device.

[0034] An even number of switches can be two, four, six, eight, etc. That is to say, the first series connection can include two switches, four switches, six switches, eight switches, etc.

[0035] A switch can be connected in series between two terminals, such that when the switch is in the ON state, the switch allows unidirectional current flow from the first terminal to the second terminal of the two terminals.

[0036] The diodes of the first diode circuit can be arranged to be electrically connected in the second series connection, such that the diodes of the first diode circuit allow unidirectional current flow of the charging current from the first terminal to the center node of the first series connection. In other words, the diodes of the first diode circuit can be arranged to be electrically connected in the second series connection, such that the cathode of each diode of the first diode circuit points to the center node of the first series connection.

[0037] The diodes of the second diode circuit can be arranged to be electrically connected in the third series connection, such that the diodes of the second diode circuit allow unidirectional current flow of the charging current from the center node of the first series connection to the second terminal. In other words, the diodes of the second diode circuit can be arranged to be electrically connected in the third series connection, such that the anode of each diode in the second diode circuit points to the center node of the first series connection.

[0038] In one implementation of the first aspect, the switching device includes a third diode circuit and a fourth diode circuit, each including at least one diode. The second series-connected first capacitor and the third series-connected second capacitor can be electrically connected to the node between the two switches. The third diode circuit can be electrically connected between the first terminal and the node between the second capacitor and the second diode circuit. The fourth diode circuit can be electrically connected between the second terminal and the node between the first capacitor and the first diode circuit. At least one diode of the third diode circuit can be arranged in anti-parallel with at least one diode of the first diode circuit; and at least one diode of the fourth diode circuit can be arranged in anti-parallel with at least one diode of the second diode circuit.

[0039] The third and fourth diode circuits allow the switching device to be used as a bidirectional switch because, together with the first and second diode circuits, they allow charging of the first and second capacitors from the first terminal to the second terminal and from the second terminal to the first terminal.

[0040] The first series-connected switch can be a bidirectional switch. This allows bidirectional switching to be implemented using a switching device.

[0041] At least one diode in the third diode circuit can be arranged to be electrically connected such that at least one diode in the third diode circuit allows unidirectional current flow from the node between the two switches in the first series connection to the first terminal. Specifically, the cathode of at least one diode in the third diode circuit can be electrically connected to the first terminal. In other words, at least one diode in the third diode circuit can be arranged to be electrically connected such that its cathode points towards the first terminal.

[0042] At least one diode in the fourth diode circuit can be arranged to be electrically connected such that at least one diode in the fourth diode circuit allows unidirectional current flow of the charging current from the second terminal to the node between the two switches connected in series in the first terminal. Specifically, the anode of at least one diode in the fourth diode circuit can be electrically connected to the second terminal. In other words, at least one diode in the fourth diode circuit can be arranged to be electrically connected such that its anode points towards the second terminal.

[0043] In one implementation of the first aspect, the first series connection comprises an even number of switches, greater than or equal to four, wherein the switches are semiconductor switches. The second and third series connections may each be electrically connected to a node at the center of the first series connection, the node being the central node of the first series connection. The first capacitor of the second series connection and the second capacitor of the third series connection may be electrically connected to the central node of the first series connection. The first, second, third, and fourth diode circuits may each comprise a number of diodes equal to half the even number of the switches; and each diode in the first, second, third, and fourth diode circuits may be connected in series with each other.

[0044] The more switches connected in the first series, the lower the blocking voltage of each switch. This reduces cost and conduction losses. As mentioned above, since existing device matching for the switches in the first series connection is not required, a larger number of switches does not increase the complexity of implementing the switching device.

[0045] The diodes in the third diode circuit can be arranged to be electrically connected separately, such that the diodes in the third diode circuit allow unidirectional current flow from the center node of the first series connection to the first terminal. In other words, the diodes in the third diode circuit can be arranged to be electrically connected in series with each other, such that the cathode of each diode in the third diode circuit points to the first terminal.

[0046] The diodes in the fourth diode circuit can be arranged to be electrically connected separately, such that the diodes in the fourth diode circuit allow unidirectional current flow from the second terminal to the central node of the first series connection. In other words, the diodes in the fourth diode circuit can be arranged to be electrically connected in series with each other, such that the anode of each diode in the fourth diode circuit points to the second terminal.

[0047] In one implementation of the first aspect, the switching device includes a third capacitor for each node between two diodes in the first diode circuit, between two diodes in the second diode circuit, and optionally between two diodes in the third diode circuit and between two diodes in the fourth diode circuit. The nodes between two diodes in the first diode circuit and optionally between two diodes in the third diode circuit can be electrically connected via the corresponding third capacitor to the nodes between two switches in the first portion of the first series connection between the first terminal and the central node of the first series connection, such that the corresponding nodes between two diodes are arranged in the series connection of the diodes in the corresponding diode circuit at the same position as the nodes between two switches in the first portion of the first series connection, and the corresponding nodes between two diodes are electrically connected to the nodes between the two switches. Similarly, each node between two diodes in the second diode circuit and optionally between two diodes in the fourth diode circuit can be electrically connected via the corresponding third capacitor to the nodes between two switches in the second portion of the first series connection between the central node of the first series connection and the second terminal, such that the corresponding nodes between two diodes are arranged in the series connection of the diodes in the corresponding diode circuit at the same position as the nodes between two switches in the second portion of the first series connection, and the corresponding nodes between two diodes are electrically connected to the nodes between the two switches.

[0048] When voltage is applied to the two terminals of the switching device, the third capacitor allows for voltage balance of the voltage applied to each of the first series-connected switches.

[0049] In one implementation of the first aspect, the first capacitor and the second capacitor have the same capacitance.

[0050] In one implementation of the first aspect, a third capacitor electrically connected to the same node between the two switches in the first series connection has the same capacitance.

[0051] Optionally, all capacitors in the switching device have the same capacitance.

[0052] In one implementation of the first aspect, the diode of the switching device is used to provide a current path for charging current used to charge the first capacitor and the second capacitor when all switches are in a non-conducting state.

[0053] Specifically, when all switches are in the non-conducting state, one or more diodes in the first diode circuit and one or more diodes in the second diode circuit can provide a current path for the charging current from the first terminal to the second terminal. Specifically, one or more diodes in the first diode circuit can provide a current path for the charging current from the first terminal to the first capacitor. One or more diodes in the second diode circuit can provide a current path for the charging current from the second capacitor to the second terminal. Therefore, the charging current can be provided from the first terminal to the second terminal via one or more diodes in the first diode circuit, the first capacitor, the second capacitor, and one or more diodes in the second diode circuit.

[0054] When all switches are in the non-conducting state, one or more diodes of the optional fourth diode circuit and one or more diodes of the optional third diode circuit can provide a current path for the charging current from the second terminal to the first terminal. Specifically, one or more diodes of the fourth diode circuit can provide a current path for the charging current from the second terminal to the first capacitor. One or more diodes of the third diode circuit can provide a current path for the charging current from the second capacitor to the first terminal. Therefore, the charging current can be provided from the second terminal to the first terminal via one or more diodes of the optional fourth diode circuit, the first capacitor, the second capacitor, and one or more diodes of the optional third diode circuit.

[0055] In one implementation of the first aspect, in order to switch the switching device between an on state and an off state, the switches are controlled such that at least two of the switches do not switch between the on state and the off state simultaneously.

[0056] Therefore, there is no need for existing device matching of the first series-connected switch, which is advantageous for the reasons mentioned above.

[0057] In the ON state of a switching device, all switches of the switching device are ON, and in the OFF state of the switching device, all switches of the switching device are OFF. Therefore, in the ON state of the switching device, a current path for the load current is provided through all switches between the two terminals of the switching device. If at least one switch in the switching device is a unidirectional switch, the current path is unidirectional. If the switch is bidirectional, the current path is bidirectional. In the OFF state of the switching device, the switching device does not provide a current path for the load current. Therefore, the ON state of the switching device corresponds to the ON state of a single semiconductor switch, and the OFF state of the switching device corresponds to the OFF state of a single semiconductor switch. The OFF state can also be called a "zero state" or "open state." The ON state can also be called a "closed state." "Switching to ON state" and "closed" can be used as synonyms. "Switching to OFF state" and "open" can be used as synonyms.

[0058] In one implementation of the first aspect, in order to switch the switching device between an on state and a non-on state, the switch is controlled such that the switch switches sequentially between the on state and the non-on state according to the order in the first series connection.

[0059] Therefore, there is no need for existing device matching of the first series-connected switch, which is advantageous for the reasons mentioned above.

[0060] Specifically, the possible scenarios are: when the switching device comprises two switches respectively, or when the switching device comprises an even number of switches equal to two.

[0061] In one implementation of the first aspect, in order to switch the switching device between an on state and an off state, the switch is controlled such that one of the switches electrically connected to one of the two terminals first switches between the on state and the off state.

[0062] Specifically, the possible scenarios are: when the switching device comprises two switches respectively, or when the switching device comprises an even number of switches equal to two.

[0063] In one implementation of the first aspect, where the first series connection comprises an even number of switches of four or more:

[0064] In terms of nodes, two switches equidistant from the central node of the first series connection are switch pairs, such that the first series connection includes multiple switch pairs; and

[0065] In order to switch the switching device between an on state and a non-on state, the switch is controlled such that:

[0066] At least one switch pair of the plurality of switch pairs simultaneously switches between the on state and the off state, and

[0067] The two switches of each of the other switch pairs of the plurality of switch pairs are switched sequentially.

[0068] In other words, when the number of nodes between each switch of the two switches and the central node of the first series connection is the same, the two switches in the first series connection correspond to a switch pair. That is, the number of nodes between the first switch and the central node in the two switches, and the number of nodes between the second switch and the central node in the two switches, are equal to each other.

[0069] In one implementation of the first aspect, in order to switch the switching device between the on state and the off state, the switch is controlled such that: both switches of each of the plurality of switch pairs switch simultaneously between the on state and the off state, wherein at least two switch pairs of the plurality of switch pairs do not switch simultaneously between the on state and the off state.

[0070] In one implementation of the first aspect, in order to switch the switching device from the conducting state to the non-conducting state, the switch is controlled such that:

[0071] The switch pair includes two switches electrically connected to the two terminals of the switching device.

[0072] The switch pair includes two switches electrically connected to the center node of the first series connection.

[0073] First, the switch is switched from the conducting state to the non-conducting state, and then the other switch pairs of the plurality of switch pairs are switched from the conducting state to the non-conducting state in sequence according to the order of the other switch pairs in the first series connection.

[0074] Switching the first series-connected switch from an ON state to a OFF state causes the switch pair, comprising two switches electrically connected to the two terminals of the switching device, to be switched first, thereby charging the respective capacitors of the switching device. Switching the first series-connected switch from an ON state to a OFF state causes the switch pair, comprising two switches electrically connected to the central node of the first series connection, to be switched first, thereby discharging the respective capacitors of the switching device.

[0075] In order to switch the switching device from the non-conducting state to the conducting state, the switch can be controlled such that:

[0076] The switch pair, comprising the two switches electrically connected to the two terminals of the switching device, or

[0077] The switch pair including the two switches electrically connected to the center node of the first series connection

[0078] First, the switch is switched from the non-conducting state to the conducting state, and then the other switch pairs of the plurality of switch pairs are switched from the non-conducting state to the conducting state in sequence according to the order of the other switch pairs in the first series connection.

[0079] Switching the first series-connected switch from a non-conducting state to a conducting state causes the switch pair, comprising two switches electrically connected to the two terminals of the switching device, to be switched first, thereby discharging the respective capacitors of the switching device. Switching the first series-connected switch from a non-conducting state to a conducting state causes the switch pair, comprising two switches electrically connected to the central node of the first series connection, to be switched first, thereby charging the respective capacitors of the switching device.

[0080] Therefore, controlling which switch pair is switched first allows for the charging and discharging of the individual capacitors in the control switching device, causing each capacitor to reach its corresponding voltage. This allows for voltage balance control over the voltage applied to the first series-connected switch, since the voltage applied to the first series-connected switch depends on the voltage between the two terminals of the switching device, as well as the voltages of the first capacitor, the second capacitor, and optionally the third capacitor.

[0081] In one implementation of the first aspect, in order to switch the switching device from the on state to the off state and from the off state to the on state, the switch is controlled such that switching begins by means of the following:

[0082] The switch pair, comprising the two switches electrically connected to the two terminals of the switching device, or

[0083] The switch pair includes the two switches that are electrically connected to the central node of the first series connection.

[0084] This ensures that the charging state of each capacitor in the switching device remains constant during the corresponding charging state. That is, when first switching a pair of switches, including two switches electrically connected to the two terminals of the switching device, the capacitors are charged when the switching device is switched, thus the switch pair sequentially changes from an on state to a non-conducting state. Then, each capacitor discharges, and when the switching device is switched, the switch pair sequentially changes from a non-conducting state to an on state. Similarly, when first switching a pair of switches, including two switches electrically connected to the central node of the first series connection, the capacitors discharge when the switching device is switched, thus the switch pair sequentially changes from an on state to a non-conducting state. Then, each capacitor is charged, and when the switching device is switched, the switch pair sequentially changes from a non-conducting state to an on state.

[0085] In order to implement the switching device according to the first aspect of this disclosure, some or all of the implementations and optional features of the first aspect as described above can be combined with each other.

[0086] A second aspect of this disclosure provides a method for switching a switching device according to the first aspect or any implementation thereof, as described above, between an on state and a non-on state. The method includes the step of controlling the switching device such that at least two switches of the device do not simultaneously switch between the on state and the non-on state.

[0087] The second aspect's method, its implementation, and optional features achieve the same advantages as the first aspect's switching device, its corresponding implementation, and its corresponding optional features.

[0088] The implementation method and optional features of the switching device according to the first aspect are correspondingly effective for the method according to the second aspect.

[0089] In one implementation of the second aspect, the method includes the following steps: controlling the switch of the switching device such that the switch sequentially switches between the conducting state and the non-conducting state according to the order in the first series connection.

[0090] In one implementation of the second aspect, the method includes the following steps: controlling the switch of the switching device such that one of the switches electrically connected to one of the two terminals first switches between the on state and the off state.

[0091] In one implementation of the second aspect, where the first series connection of the switching device comprises an even number of switches of four or more, the method includes the step of: controlling the switching of the switching device such that:

[0092] At least one switch pair of the plurality of switch pairs simultaneously switches between the on state and the off state, and

[0093] The two switches of each of the other switch pairs of the plurality of switch pairs are switched sequentially.

[0094] In one implementation of the second aspect, where the first series connection of the switching device comprises an even number of switches of four or more, the method includes the following steps: controlling the switches of the switching device such that: two switches in each of the plurality of switch pairs simultaneously switch between the on state and the off state, wherein at least two of the plurality of switch pairs do not simultaneously switch between the on state and the off state.

[0095] In one implementation of the second aspect, where the first series connection of the switching device comprises an even number of switches of four or more, the method includes the step of: controlling the switching of the switching device such that:

[0096] The switch pair includes two switches electrically connected to the two terminals of the switching device.

[0097] The switch pair includes two switches electrically connected to the center node of the first series connection.

[0098] First, the switch is switched from the conducting state to the non-conducting state, and then the other switch pairs of the plurality of switch pairs are switched from the conducting state to the non-conducting state in sequence according to the order of the other switch pairs in the first series connection, so as to switch the switching device from the conducting state to the non-conducting state.

[0099] Furthermore, the method may include the following steps: controlling the switch of the switching device such that:

[0100] The switch pair, comprising the two switches electrically connected to the two terminals of the switching device, or

[0101] The switch pair including the two switches electrically connected to the center node of the first series connection

[0102] First, the switch is switched from the non-conducting state to the conducting state, and then the other switch pairs of the plurality of switch pairs are switched from the non-conducting state to the conducting state in sequence according to the order of the other switch pairs in the first series connection, so as to switch the switching device from the non-conducting state to the conducting state.

[0103] In one implementation of the second aspect, where the first series connection of the switching device comprises an even number of switches of four or more, the method includes the following steps: controlling the switching of the switching device such that switching begins by means of the following.

[0104] The switch pair, comprising the two switches electrically connected to the two terminals of the switching device, or

[0105] The switch pair includes the two switches electrically connected to the central node of the first series connection.

[0106] Used to switch the switching device from the on state to the off state and from the off state to the on state.

[0107] In order to implement the method according to the second aspect of this disclosure, some or all of the implementations and optional features of the second aspect as described above can be combined with each other.

[0108] A third aspect of this disclosure provides a converter system having at least one converter. The at least one converter includes at least one switching device according to the first aspect described above or any implementation thereof, for controlling the power conversion of the at least one converter.

[0109] The converter system of the third aspect, its implementation and optional features achieve the same advantages as the switching device of the first aspect, its corresponding implementation and optional features.

[0110] The implementation method and optional features of the switching device according to the first aspect are correspondingly effective for the converter system according to the third aspect.

[0111] In one implementation of the third aspect, the converter system includes a control unit. The control unit is configured to control the power conversion of the at least one converter by performing the method described according to the second aspect or any implementation thereof as described above, for switching at least one switching device of the at least one converter between an on state and an off state.

[0112] A fourth aspect of this disclosure provides a control unit for controlling the switching of at least one switching device according to the first aspect or any implementation thereof by performing the method described in accordance with the second aspect as described above or any implementation thereof.

[0113] A fifth aspect of this disclosure provides a converter including at least one switching device according to the first aspect as described above or any implementation thereof, for controlling the power conversion of the converter.

[0114] At least one converter in the converter system according to the third aspect and the converter according to the fifth aspect can be an AC / DC converter, a DC / AC converter, a DC / DC converter, and / or an AC / AC converter. Specifically, at least one converter in the converter system according to the third aspect and the converter according to the fifth aspect can be a T-type converter, such as a 3-stage T-type converter; a nested T-type converter, such as a 3-stage nested T-type converter or a 5-stage nested T-type converter; a monkey head converter; a Vienna converter / rectifier; and a matrix converter.

[0115] A sixth aspect of this disclosure provides a computer program including program code for performing the method described in accordance with the second aspect as described above or any implementation thereof.

[0116] A seventh aspect of this disclosure provides a non-transitory storage medium for storing executable program code, which, when executed by a control unit, causes the method described in accordance with the second aspect as described above or any implementation thereof to be executed.

[0117] The control unit of the converter system according to the third aspect, the control unit according to the fourth aspect, and the control unit for executing program code stored in the non-transitory medium according to the seventh aspect may include or correspond to a processor, microprocessor, controller, microcontroller, field-programmable gate array (FPGA), application-specific integrated circuit (ASIC), or any combination thereof.

[0118] The eighth aspect of this disclosure provides a switching device for a converter. The switching device includes an even number of switches (greater than or equal to two), wherein the switches are semiconductor switches, and two diode circuits, each diode circuit including diodes equal to the even number of the switches. The switches are connected in series between two terminals of the switching device. Diodes of a first diode circuit of the two diode circuits are connected in series between two terminals of the switching device. Diodes of a second diode circuit of the two diode circuits are connected in series between two terminals of the switching device. The series connection of the diodes of the first diode circuit, the series connection of the diodes of the second diode circuit, and the series connection of the switches are connected in parallel. The diodes of the first diode circuit of the two diode circuits are connected in series such that the cathode of each diode of the first diode circuit points to a node at the center of the series connection of the diodes of the first diode circuit. The node at the center of the series connection of the diodes of the first diode circuit corresponds to the center node of the first diode circuit. That is, when the first diode circuit includes two diodes, the anode of the first diode can be electrically connected to a first terminal of the two terminals, the cathode of the first diode can be connected to the cathode of the second diode of the two diodes, and the anode of the second diode can be connected to a second terminal of the two terminals. When the first diode circuit includes at least four diodes, two or more diodes between the first terminal and the center node of the first diode circuit can be connected such that the cathode of one diode is connected to the anode of another diode or to the center node of the first diode circuit; and two or more diodes between the second terminal and the center node of the first diode circuit can be connected such that the cathode of one diode is connected to the anode of another diode or to the center node of the first diode circuit. The diodes of the second diode circuit are connected in series, such that the anode of each diode in the second diode circuit points to the node at the center of the series connection of the diodes in the second diode circuit. The node at the center of the series connection of the diodes in the second diode circuit corresponds to the center node of the second diode circuit. That is, when the second diode circuit includes two diodes, the cathode of the first diode of the two diodes can be electrically connected to the first terminal, the anode of the first diode can be connected to the anode of the second diode of the two diodes, and the cathode of the second diode can be connected to the second terminal.When the second diode circuit includes at least four diodes, two or more diodes between the first terminal and the center node of the second diode circuit can be connected such that the anode of one diode is connected to the cathode of another diode or to the center node of the second diode circuit; and two or more diodes between the second terminal and the center node of the second diode circuit can be connected such that the anode of one diode is connected to the cathode of another diode or to the center node of the second diode circuit. For each node between the two diodes of the two diode circuits, the switching device includes a capacitor. Each node between the two diodes of the two diode circuits is electrically connected via the corresponding capacitor to a node between two switches in a series connection of the switches, such that the corresponding node between the two diodes is arranged in the series connection of the diodes of the corresponding diode circuit at the same position as the node between the two switches in the series connection of the switches, and the corresponding node between the two diodes is connected to the node between the two switches.

[0119] The switching device in the eighth aspect can be used to implement semiconductor switches of the converter, especially bidirectional semiconductor switches.

[0120] In one implementation of the eighth aspect, the switch is a bidirectional semiconductor switch.

[0121] A ninth aspect of this disclosure provides a switching device for a converter. The switching device includes two switches connected in series with each other between two terminals, such that, in an ON state, the two switches allow unidirectional current flow from a first terminal to a second terminal. The two switches are semiconductor switches. The switching device further includes a first diode and a first capacitor connected in series between the first terminal and a node between the two switches, wherein the cathode of the first diode points towards the node between the two switches. The switching device also includes a second diode and a second capacitor connected in series between the second terminal and the node between the two switches, wherein the anode of the second diode points towards the node between the two switches. The series connection of the first diode and the first capacitor is connected in parallel to the first switch, which is electrically connected to the first terminal. The series connection of the second diode and the second capacitor is connected in parallel to the second switch, which is electrically connected to the second terminal.

[0122] The switching device described in the ninth aspect can be used to implement semiconductor switches of the converter, particularly unidirectional semiconductor switches.

[0123] "The cathode of the first diode points to the node between the two switches" means that the cathode of the first diode is electrically connected to the node between the two switches, or the anode of the first diode is electrically connected to the first terminal. "The anode of the second diode points to the node between the two switches" means that the anode of the second diode is electrically connected to the node between the two switches, or the cathode of the second diode is electrically connected to the second terminal.

[0124] Therefore, the anode of the first diode can be connected to the first terminal, and the cathode of the first diode can be connected to the first capacitor. Alternatively, the first capacitor can be connected to the first terminal, the anode of the first diode can be connected to the first capacitor, and the cathode of the first diode can be connected to the node between the two switches. The cathode of the second diode can be connected to the second terminal, and the anode of the second diode can be connected to the second capacitor. Alternatively, the second capacitor can be connected to the second terminal, the cathode of the second diode can be connected to the second capacitor, and the anode of the second diode can be connected to the node between the two switches.

[0125] In one implementation of the ninth aspect, at least one of the two switches is a unidirectional semiconductor switch. Specifically, the two switches may be unidirectional semiconductor switches.

[0126] A tenth aspect of this disclosure provides a switching device for a converter. The switching device includes an even number of switches (four or more), wherein the switches are semiconductor switches, and two diode circuits, each diode circuit including diodes equal to half the number of the even number of the switches. The switches are electrically connected in series between two terminals of the switching device such that, in the on state, the switches allow unidirectional current flow from a first terminal to a second terminal of the two terminals. A node at the center of the series connection of the switches is the central node of the series connection of the switches. The diodes of each of the two diode circuits are electrically connected in series with each other. One end of the series connection of the diodes of the first diode circuit is electrically connected to the first terminal, and the other end is electrically connected via a first capacitor to the central node of the series connection of the switches. A first portion of the series connection of the switches between the diodes of the first diode circuit and the first capacitor is electrically connected in parallel with the central node of the series connection of the switches between the first terminal and the central node of the series connection of the switches. The diodes of the first diode circuit are electrically connected in series such that the cathode of each diode of the first diode circuit points to the central node of the series connection of the switches. In other words, when the first diode circuit includes two diodes, the anode of the first diode can be electrically connected to the first terminal, the cathode of the first diode can be connected to the anode of the second diode, and the cathode of the second diode can be connected to the first capacitor. When the first diode circuit includes at least three diodes, the anode of the first diode of the at least three diodes can be electrically connected to the first terminal, and the cathode of the second diode of the at least three diodes can be electrically connected to the first capacitor. One or more additional diodes of the first diode circuit can be electrically connected such that the anode of each of the one or more additional diodes is connected to the cathode of the preceding diode, and the cathode of each of the one or more additional diodes is connected to the anode of the following diode.

[0127] One end of the series connection of the diodes in the second diode circuit of the two diode circuits is electrically connected to the second terminal, and the other end is electrically connected to the center node of the series connection of the switches via the second capacitor. The series connection of the diodes and the second capacitor in the second diode circuit is connected in parallel to a second portion of the series connection of the switches between the second terminal and the center node of the series connection of the switches. The diodes in the second diode circuit are connected in series such that the anode of each diode in the second diode circuit points to the center node of the series connection of the switches. That is, when the second diode circuit includes two diodes, the cathode of the first diode of the two diodes can be electrically connected to the second terminal, the anode of the first diode can be connected to the cathode of the second diode of the two diodes, and the anode of the second diode can be connected to the second capacitor. When the second diode circuit includes at least three diodes, the cathodes of the first diodes of the at least three diodes can be electrically connected to the second terminal, and the anodes of the second diodes of the at least three diodes can be electrically connected to the second capacitor. One or more additional diodes in the second diode circuit can be electrically connected such that the anode of each of the one or more additional diodes is connected to the cathode of the preceding diode, and the cathode of each of the one or more additional diodes is connected to the anode of the following diode.

[0128] The switching device of the tenth aspect can be used to implement semiconductor switches of the converter, especially unidirectional semiconductor switches.

[0129] In one implementation of the tenth aspect, at least one switch of the switching device is a unidirectional semiconductor switch. Specifically, the switch of the switching device may be a unidirectional semiconductor switch.

[0130] In one implementation of the tenth aspect, for each node between the two diodes of the two diode circuits, the switching device includes a third capacitor. Each node between the two diodes of the first diode circuit is electrically connected via the corresponding third capacitor to a node between the two switches in a first portion of the series connection of the switches, such that the corresponding node between the two diodes is arranged in the series connection of the diodes of the first diode circuit at the same position as the node between the two switches in the first portion of the series connection of the switches, and the corresponding node between the two diodes is connected to the node between the two switches. Similarly, each node between the two diodes of the second diode circuit is electrically connected via the corresponding third capacitor to a node between the two switches in a second portion of the series connection of the switches, such that the corresponding node between the two diodes is arranged in the series connection of the diodes of the second diode circuit at the same position as the node between the two switches in the second portion of the series connection of the switches, and the corresponding node between the two diodes is connected to the node between the two switches.

[0131] In one implementation of the eighth, ninth, and tenth aspects, capacitors electrically connected to the same node between two series-connected switches of the switch have the same capacitance.

[0132] In one implementation of the ninth and tenth aspects, the first capacitor and the second capacitor have the same capacitance.

[0133] In one implementation of the eighth, ninth, and tenth aspects, the diode of the switching device is used to provide a current path for charging current for charging a capacitor at the center of a series connection electrically connected to the switches, when all switches are in a non-conducting state.

[0134] In one implementation of the ninth aspect, the first diode and the second diode are used to provide a current path for charging current used to charge the first capacitor and the second capacitor when all switches are in the non-conducting state.

[0135] In one implementation of the tenth aspect, the diode of the switching device is used to provide a current path for charging current used to charge the first capacitor and the second capacitor when all switches are in a non-conducting state.

[0136] The implementation mode and optional features of the switching device according to the first aspect are correspondingly effective for the switching devices according to the eighth, ninth, and tenth aspects. Specifically, the implementation mode and optional features of the switching device according to the first aspect are correspondingly effective for the switching devices according to the eighth, ninth, and tenth aspects.

[0137] To implement the switching device according to the eighth aspect, some or all of the implementations and optional features of the eighth aspect as described above can be combined with each other. To implement the switching device according to the ninth aspect, some or all of the implementations and optional features of the ninth aspect as described above can be combined with each other. To implement the switching device according to the tenth aspect, some or all of the implementations and optional features of the tenth aspect as described above can be combined with each other.

[0138] The method described in the second aspect or any of its implementations can be used for:

[0139] The switching device according to the eighth aspect or any implementation thereof

[0140] The switching device according to the ninth aspect or any implementation thereof, and

[0141] The switching device according to the tenth aspect or any implementation thereof switches between an on state and an off state.

[0142] The control unit according to the fourth aspect, the converter according to the fifth aspect, the computer program according to the sixth aspect, the non-transitory storage medium according to the seventh aspect, the switching device according to the eighth aspect, the switching device according to the ninth aspect, and the switching device according to the tenth aspect all achieve the same advantages as the switching device according to the first aspect.

[0143] It should be noted that all devices, elements, units, and apparatuses described in this application can be implemented in software or hardware elements or any combination thereof. All steps performed by various entities and functions performed by various entities as described in this application are intended to indicate that each entity is suitable for or used to perform its respective steps and functions. Even in the following description of specific embodiments, if a particular function or step performed by an external entity is not reflected in the description of the specific detailed elements of the entity performing that particular step or function, it will be clear to those skilled in the art that these methods and functions can be implemented in various software or hardware elements or any combination thereof. Attached Figure Description

[0144] The above aspects and implementations of this disclosure will be explained in the following description of specific embodiments with reference to the accompanying drawings, wherein,

[0145] Figure 1 Examples of unidirectional semiconductor switches are shown (see (a1), (a2), and (a3)) and examples of bidirectional semiconductor switches (see (b1), (b2), (b3), (b4), and (b5)).

[0146] Figures 2 to 7 A switching device according to an example of the present invention is shown.

[0147] Figure 8 An example according to the invention is shown. Figure 3 The switching state of the switching device when switching between the on and off states.

[0148] Figure 9 and Figure 10 An example according to the invention is shown respectively. Figure 6 (a) The switching state when the switching device switches between the on state and the off state.

[0149] Figure 11 An example according to the invention is shown. Figure 6 (a) Figure 9 and Figure 10 The voltage curve of the switching device as it switches between the on and off states over time.

[0150] Figure 12 An example according to the invention is shown. Figure 6 (b) Voltage curves over time as the switching device switches between the on and off states.

[0151] Figures 13 to 16 A converter system and converter according to an example of the present invention are shown.

[0152] In the accompanying drawings, corresponding elements are labeled with the same reference numerals. Detailed Implementation

[0153] Figure 1 Examples of unidirectional semiconductor switches are shown (see (a1), (a2), and (a3)) and examples of bidirectional semiconductor switches (see (b1), (b2), (b3), (b4), and (b5)).

[0154] Figure 1 (a1) shows the symbols for unidirectional control switches (UCS) used for unidirectional semiconductor switches. Figure 1 (a2) and Figure 1 (a3) illustrates two possible implementations of a unidirectional semiconductor switch, in which, Figure 1(a2) shows an IGBT with diodes connected in anti-parallel. Figure 1 (a3) shows an IGBT with diodes connected in series.

[0155] Figure 1 (b1) shows the symbols for a bidirectional control switch (BCS) used for a bidirectional semiconductor switch. Figure 1 (b2) to Figure 1 (b5) illustrates various possible implementations of a bidirectional semiconductor switch. Figure 1 (b2) and Figure 1 The configuration shown in (b3) is called an anti-series (back-to-back) bidirectional semiconductor switch, consisting of two common-emitter (e.g.) Figure 1 (b2) shown) or common collector electrode (as shown) Figure 1 The IGBT implementation shown in (b3). Figure 1 The configuration shown in (b4) is called a bidirectional semiconductor switch with a diode bridge, wherein the bidirectional semiconductor switch can be formed by a diode bridge and an IGBT. Figure 1 The configuration shown in (b5) can be referred to as an anti-parallel bidirectional semiconductor switch using a reverse blocking IGBT (RB-IGBT).

[0156] A bidirectional semiconductor switch can be used to control current in two directions. Figure 1 The common collector configuration of the anti-series bidirectional semiconductor switch shown in (b3) requires a separate isolated gate driver for each power switch, whereas a single driver is sufficient for the common emitter configuration, at the cost of separate current direction control. A bidirectional semiconductor switch with a diode bridge consists of a single power switch and four diodes, thus requiring only one gate driver. An anti-parallel bidirectional semiconductor switch requires additional diodes for each current direction and a separate gate driver for each power switch.

[0157] Figures 2 to 7 A switching device according to an embodiment of the present invention is shown.

[0158] Figure 2 An embodiment of the switching device according to the first aspect and an embodiment of the switching device according to the tenth aspect are shown.

[0159] Therefore, the above descriptions of the switching device in the first aspect and the switching device in the tenth aspect are for Figure 2 The switching device is therefore effective.

[0160] like Figure 2As shown, the switching device 1 includes an even number of switches S, greater than or equal to two, between its two terminals T1 and T2. Li S L2 S L1 S R1 S R2 S Ri The first series connection SC1, wherein switch S Li S L2 S L1 S R1 S R2 S Ri It is a semiconductor switch. For example... Figure 2 As shown, switch S Li S L2 S L1 S R1 S R2 S Ri It is a unidirectional semiconductor switch. Alternatively, switch S Li S L2 S L1 S R1 S R2 S Ri At least one switch in the circuit can be a bidirectional semiconductor switch. An even number of switches can be equal to two (this is the case in...). Figure 3 (shown in the middle), four (this situation in) Figure 4 (as shown in (a)), six (this case is in) Figure 4 (b) shown) or an even number greater than the above number. Switching device 1 can also be called a nested directional switch (NDS), particularly an N-level nested directional switch (N-level NDS), where N is the number of even-numbered switches S1 connected in series in the first series connection of switching device 1 SC1. Li S L2 S L1 S R1 S R2 S Ri That is to say, it includes two switches S. L1 S R1 The switching device corresponds to Level 2 NDS and includes four switches S. L2 S L1 S R1 S R2 The switching device corresponds to level 4 NDS, including six switches S L3 S L2 S L1 SR1 S R2 S R3 The switching device corresponds to level 6 NDS, etc. Figure 2 The switch device 1 shown corresponds to a unidirectional semiconductor switch, which can also be called a nested unidirectional switch.

[0161] Figure 2 The switching device 1 may include an even number of low-voltage semiconductor switches S, which is greater than or equal to two. Li S L2 S L1 S R1 S R2 S Ri This is used to implement a switch between terminals T1 and T2 with a blocking voltage higher than that of each low-voltage semiconductor switch. The total blocking capability of the switching device, i.e., the total blocking capability of the switch implemented between terminals T1 and T2, is equal to the even number of switches S in the switching device. Li S L2 S L1 S R1 S R2 S Ri Multiply by each switch S Li S L2 S L1 S R1 S R2 S Ri Blocking ability V 阻断 (2*(i)*V blocking, where i is an integer greater than or equal to 1). The switching device 1 includes 2*i semiconductor switches (i is an integer greater than or equal to 1) to achieve a switch with a blocking voltage higher than the blocking voltage of each semiconductor switch.

[0162] The switching device 1 further includes a second series connection SC2 of the first capacitor C1 and the first diode circuit D1, wherein the second series connection SC2 is electrically connected in parallel with the first portion P1 of the first series connection SC1 between the first terminal T1 of the two terminals T1 and T2 and the node Nc at the center of the first series connection SC1, and the node Nc is the center node of the first series connection SC1. The switching device 1 further includes a third series connection SC3 of the second capacitor C2 and the second diode circuit D2, wherein the third series connection SC3 is electrically connected in parallel with the second portion P2 of the first series connection SC1 between the second terminal T2 of the two terminals T1 and T2 and the center node Nc of the first series connection SC1.

[0163] like Figure 2As shown, the first capacitor C1 of the second series connection SC2 and the second capacitor C2 of the third series connection SC3 are electrically connected to the center node Nc of the first series connection SC1. A first diode circuit D1 is connected between the first terminal T1 and the first capacitor C1, wherein the node between the first diode circuit D1 and the first capacitor C1 is marked with reference numeral N1. A second diode circuit D2 is connected between the second terminal T2 and the second capacitor C2, wherein the node between the second diode circuit D2 and the second capacitor C2 is marked with reference numeral N2.

[0164] The first diode circuit D1 includes an even number (2*i) of switches S. Li S L2 S L1 S R1 S R2 S R1 Half of the diode D1 i ..., D12, D11. That is, the first diode circuit D1 includes at least one diode. When the first diode circuit D1 includes two or more diodes, the diodes are connected in series. For example... Figure 2 As shown, diode D1 in the first diode circuit D1 i D1, ..., D12, D11 are connected in series, so that each diode D1... i The cathodes of D11, D12, and D11 point towards the center node Nc of the first series connection SC1, and thus towards the first capacitor C1. In other words, diode D1 of the first diode circuit D1... i The diodes D1, D12, and D11 are electrically connected such that the cathode of the first diode circuit D1 is electrically connected to the anode of another diode (such as diode D1). i (This is the case with D12) or electrically connected to the first capacitor C1 (such as diode D11). Therefore, when the first series-connected switch S of SC1... Li S L2 S L1 S R1 S R2 S Ri When in a non-conducting state, diode D1 of the first diode circuit D1 i D11, ..., D12, D11 allow unidirectional current flow of the charging current from the first terminal T1 to the center node Nc of the first series connection SC1 for charging the first capacitor C1 and the second capacitor C2.

[0165] The second diode circuit D2 includes an even number (2*i) of switches S. Li S L2 SL1 S R1 S R2 S Ri Half of the diodes D21, D22, ..., D2 i In other words, the second diode circuit D2 includes at least one diode. When the second diode circuit D2 includes two or more diodes, the diodes are connected in series. For example... Figure 2 As shown, the diodes D21, D22, ..., D2 in the second diode circuit D2 i They are connected in series, so that each diode D21, D22, ..., D2 i The anode of the diode points to the center node Nc of the first series connection SC1, and thus to the second capacitor C2. In other words, diodes D21, D22, ..., D2 of the second diode circuit D2... i Electrical connection, such that the anode of diode D2 in the second diode circuit is electrically connected to the cathode of another diode (e.g., diodes D22 and D2). i This is the case) or it is electrically connected to the second capacitor C2 (such as diode D21). Therefore, when the first series-connected switch S of SC1... Li S L2 S L1 S R1 S R2 S Ri When in the non-conducting state, diodes D21, D22, ..., D2 in the second diode circuit D2 i Unidirectional current flow is allowed for the charging current used to charge the first capacitor C1 and the second capacitor C2, from the center node Nc of the first series connection SC1 to the second terminal T2.

[0166] like Figure 2 As shown, for each node N[i-1] between the two diodes of the first diode circuit D1 and the two diodes of the second diode circuit D2 D1 ..., N1 D1 N1 D2 ..., N[i-1] D2 The switching device 1 may include an optional third capacitor C3. Each node between the two diodes of the first diode circuit D1 is electrically connected via a corresponding third capacitor C3 to a node between the two switches of the first part P1 of the first series connection SC1, such that the corresponding nodes between the two diodes are arranged at the same positions as the nodes between the two switches of the first part P1 of the first series connection SC1. iIn a series connection of diodes D11, ..., D12, ..., D11, the corresponding node between two diodes is electrically connected to the node between two switches. For example, node N1 between the two diodes D12 and D11 in the first diode circuit D1. D1 Two switches S in the first part P1 connected in series with the first SC1 L2 and S L1 Node N1 between L The diode D1 is arranged at the same position as the diode in the first diode circuit D1. i In the series connection of diodes D12 and D11, the node N1 between the two diodes D12 and D11 in the first diode circuit D1 is... D1 The two switches S are connected to the first part P1 of the first series connection SC1 via the third capacitor C3. L2 and S L1 Node N1 between L .

[0167] Each node between the two diodes in the second diode circuit D2 (e.g., node N1) D2 The first series connection SC1 is electrically connected via a corresponding third capacitor C3 to the node between the two switches of the second part P2 of the first series connection SC1, which is the center node Nc of the first series connection SC1 and the second terminal T2. (e.g., node N1) R ), such that the corresponding node between the two diodes (e.g., node N1) D2 The node (e.g., node N1) between the two switches in the second part P2 of the first series connection SC1. R Diodes D21, D22, ..., D2 are arranged at the same positions as those in the second diode circuit D2. i In a series connection, the corresponding node between the two diodes (e.g., node N1) D2 Electrically connected to the node between the two switches (e.g., node N1) R ).

[0168] Based on the above, Figure 2 The number of switches, diodes, and third capacitor C3 shown is merely an example and does not limit this disclosure.

[0169] By performing the method described in the second aspect or any implementation thereof, the switching device 1 can switch between an ON state and a OFF state. Therefore, the above description of the method in the second aspect is effective in describing the switching of the switching device 1 between an ON state and a OFF state.

[0170] According to one embodiment, in order to switch the switching device 1 between an on state and a non-on state, switch S LiS L2 S L1 S R1 S R2 S Ri Being controlled, causing switch S Li S L2 S L1 S R1 S R2 S Ri According to the order in the first series connection SC1, the switches sequentially switch between the on and off states. Specifically, switch S Li S L2 S L1 S R1 S R2 S Ri It can be controlled so that the switch S connected to the first terminal T1 L1 Or a switch S connected to the second terminal Ri First, it switches between the on and off states. Figure 11 and Figure 12 Such a switching is illustrated in the example. Therefore, in order to switch the switching device 1 between the on state and the off state, the switching device switches between one or more transient states (also referred to as intermediate states).

[0171] One or more transient states last only tens or hundreds of nanoseconds. This is achieved through the switch S... Li S L2 S L1 S R1 S R2 S Ri The switching between the switches creates a delay (i.e., the switches are switched sequentially instead of simultaneously), resulting in a transient state. Therefore, the voltage between terminals T1 and T2 can be controlled by switch S. Li S L2 S L1 S R1 S R2 S Ri Equal sharing. Therefore, this disclosure proposes quasi-multilevel operation of the switching device (i.e., switching between an on state and an off state via one or more transient states depending on the number of switches of the switching device) to increase the effective voltage capability between the two terminals T1 and T2 of the switching device.

[0172] During the transient state of switching device 1, only charging current flows through one or more diodes and one or more capacitors of switching device 1. Therefore, compared with semiconductor switch S Li S L2 SL1 S R1 S R2 S Ri Compared to the rated current of the capacitor, the rated current of the diode in switching device 1 is much smaller. The diode is used to maintain the charge of the first capacitor C1, the second capacitor C2, and the optional third capacitor C3. During the transient state of switching device 1, the first capacitor C1, the second capacitor C2, and the optional third capacitor C3 can be charged or discharged. That is, the capacitors of switching device 1 operate during the transient state, and therefore, only for a very short time. Therefore, the size of the first capacitor C1, the second capacitor C2, and the optional third capacitor C3 can be very small.

[0173] The first series connection includes an even number of switches S, equal to or greater than four. Li S L2 S L1 S R1 S R2 S Ri In this case, two switches equidistant from the central node Nc of the first series connection SC1 are switch pairs, such that the first series connection SC1 includes multiple switch pairs. For example, switch S L1 and S R1 The nodes are equidistant from the central node Nc, therefore switch S L1 and S R1 They are switch pairs because they are connected to the central node Nc, therefore there are two switches S L1 S R1 There are zero nodes between each switch and the central node Nc. Switch S L2 and S R2 The nodes are equidistant from the central node Nc, therefore switch S L2 and S R2 It's a switch pair, because there are two switches S... L2 S R2 There is a node (node ​​N1) between each switch and the central node Nc. L and node N1 R ).

[0174] According to one embodiment, in order to switch the switching device 1 from the on state to the off state, switch S Li S L2 S L1 S R1 S R2 S Ri Controlled such that two switches S, including two terminals T1 and T2 electrically connected to the switching device 1, are controlled to... Li S RiThe switch pair or includes two switches S electrically connected to the center node Nc of the first series connection SC1. L1 S R1 The switch pair first switches from the on state to the off state, and the other switch pairs in the multiple switch pairs switch from the on state to the off state in sequence according to the order of the other switch pairs in the first series connection SC1.

[0175] Therefore, in order to switch the switching device 1 from the non-conducting state to the conducting state, switch S Li S L2 S L1 S R1 S R2 S Ri It can be controlled so that two switches S, including two terminals T1 and T2 electrically connected to the switching device 1, are included. Li S Ri The switch pair or includes two switches S electrically connected to the center node Nc of the first series connection SC1. L1 S R1 The switch pair first switches from the non-conducting state to the conducting state, and the other switch pairs in the multiple switch pairs switch from the non-conducting state to the conducting state in sequence according to the order of the other switch pairs in the first series connection SC1.

[0176] The switching method described above can be illustrated in Table 1 below, where "1" indicates that the switch is in the ON state and "0" indicates that the switch is in the OFF state.

[0177]

[0178] Table 1: Switching sequence for switching devices

[0179] When the switching sequence A in the left sub-column of Table 1 above is used to switch the switching device 1 from the non-conducting state to the conducting state (that is, firstly, the switch S including the connection to terminals T1 and T2 is switched on), Li S Ri When the switch pair is switched to the on state, each capacitor of the switching device 1 discharges during the transient state. When the switching sequence B in the right sub-column of Table 1 above is used to switch the switching device 1 from the non-conducting state to the on state (i.e., firstly, the switch S including the one connected to the central node Nc is switched on), L1 S R1 When the switch pair is switched to the on state, each capacitor of the switching device 1 is charged during the transient state.

[0180] When the switching sequence A in the left sub-column of Table 1 above is used to switch the switching device 1 from the on state to the off state (that is, firstly, the switch S including the one connected to the central node Nc will be switched), L1S R1 When the switch pair is switched to the non-conducting state, each capacitor of the switching device 1 discharges during the transient state. When the switching sequence B in the right sub-column of Table 1 above is used to switch the switching device 1 from the conducting state to the non-conducting state (i.e., firstly, the switch S including the one connected to terminals T1 and T2 is switched), Li S Ri When the switch pair is switched to the non-conducting state, the individual capacitors of the switching device are charged during the transient state.

[0181] In order to cyclically charge and discharge the capacitor, when the switching device 1 switches between the on and off states, switching sequences A and B can be used alternately to switch the switching device 1 between the on and off states.

[0182] As shown in Table 1, when the switch pair switches between the on and off states, both switches in each switch pair switch between the on and off states simultaneously.

[0183] Alternatively, two switches in at least one (i.e., one or more) switch pairs can be switched sequentially. This is illustrated exemplarily in Table 2 below, where, for switching sequence A, exemplarily, the two switches S forming the switch pair... L1 and S R1 They are switched sequentially, and for switching sequence B, for example, the two switches S forming a switch pair Li and S Ri They are switched sequentially.

[0184]

[0185] Table 2: Switching sequences for switching devices

[0186] Figure 3 An embodiment of the switching device according to the first aspect and an embodiment of the switching device according to the ninth aspect are shown.

[0187] Therefore, the above descriptions of the switching device in the first aspect and the switching device in the ninth aspect are for Figure 3 The switching device is therefore effective.

[0188] Figure 3 The switching device corresponds to Figure 2 The switching device, wherein, Figure 3 The even number of switches S in the first series connection of the switching device SC1 L1 S R1 The quantity is equal to two. Therefore, Figure 2 The above description of the switching device corresponds to... Figure 3 The switching device is effective, and for the description Figure 3The switching device is mainly referenced. Figure 2 The above description. Further details are provided below. Figure 3 Additional information for the embodiments.

[0189] like Figure 3 As shown, the central node Nc of the first series connection SC1 is the two switches S of the first series connection SC1. L1 and S R1 The nodes between. According to Figure 3 In the second series connection SC2, the first diode circuit D1 and the first capacitor C1 are connected such that the anode of the first diode circuit D1, specifically diode D11, is connected to the first terminal T1, and the first capacitor C1 is connected to the center node Nc. Alternatively, in the case where the first series connection SC1 includes only two switches, the first diode circuit D1 and the first capacitor C1 can be connected such that the first capacitor C1 is connected to the first terminal T1, and the cathode of the first diode circuit D1, specifically diode D11, is connected to the center node Nc.

[0190] according to Figure 3 The second diode circuit D2 and the second capacitor C2 are connected in series with SC3, such that the cathode of the second diode circuit D2, specifically diode D21, is connected to the second terminal T2, and the second capacitor C2 is connected to the center node Nc. In the case where the first series connection SC1 includes only two switches, the second diode circuit D2 and the second capacitor C2 can alternatively be connected such that the second capacitor C2 is connected to the second terminal T2, and the anode of the second diode circuit D2, specifically diode D21, is connected to the center node Nc.

[0191] Figure 4 Two embodiments of the switching device according to the first aspect and two embodiments of the switching device according to the tenth aspect are shown.

[0192] Therefore, the above descriptions of the switching device in the first aspect and the switching device in the tenth aspect are for Figure 4 The corresponding switching device is effective.

[0193] Figure 4 The switching device corresponds to Figure 2 The switching device, wherein, Figure 4 (a) The even number of switches S in the first series connection of the switching device SC1 L2 S L1 S R1 S R2 The quantity is equal to four, and Figure 4(b) The even number of switches S in the first series connection of the switching device SC1 L3 S L2 S L1 S R1 S R2 S R3 The quantity is equal to six. Therefore, Figure 2 The above description of the switching device corresponds to... Figure 4 The switching device is effective, and for the description Figure 4 Switching device, reference Figure 2 The above description.

[0194] Figure 5 An embodiment of the switching device according to the first aspect and an embodiment of the switching device according to the eighth aspect are shown.

[0195] Therefore, the above descriptions of the switching device in the first aspect and the switching device in the eighth aspect are for Figure 5 The switching device is therefore effective.

[0196] Figure 5 The switching device corresponds to Figure 2 A switching device, wherein the first switch S connected in series with SC1 Li S L2 S L1 S R1 S R2 S Ri It is a bidirectional semiconductor switch. Figure 5 The switch device 1 shown corresponds to a bidirectional semiconductor switch, which can also be called a nested bidirectional switch. Figure 2 The above description of the switching device corresponds to... Figure 5 The switching device is effective, and for the description Figure 5 The switching device is mainly referenced. Figure 2 The above description. Further details are provided below. Figure 5 Additional information for the embodiments.

[0197] Figure 5 The number of even-numbered switches in the first series connection SC1 of the switching device 1 can be equal to two (this is the case in...). Figure 6 (as shown in (a)), four (this situation is in) Figure 6 (b) shown), six (this case is in) Figure 7 (as shown in the figure) or an even number greater than the above number.

[0198] Figure 5The switching device 1 includes a third diode circuit D3 electrically connected between the first terminal T1, the second capacitor C2, and node N2 between the second diode circuit D2. The third diode circuit D3 includes an even number (2*i) of switches S, (i) equal to the number of switches S1 connected in series with the first diode circuit SC1. Li S L2 S L1 S R1 S R2 S Ri Half of the diodes. That is, the third diode circuit D3 includes at least one diode.

[0199] In the case where the third diode circuit D3 includes two or more diodes, the diodes are connected in series. For example... Figure 5 As shown, diode D3 in the third diode circuit D3 i ..., D32, D31 are connected in series, so that each diode D3... i The anodes of diodes D31, D32, and D31 point to the center node Nc of the first series connection SC1, and thus to the second capacitor C2. In other words, the diodes of the third diode circuit D3... i The diodes D3, D32, and D31 are electrically connected, such that the anode of the third diode circuit D3 is electrically connected to the cathode of another diode (e.g., diode D3). i (This is the case with D32) or electrically connected to the second capacitor C2 (as is the case with diode D31). Therefore, when the first series-connected switch S of SC1... Li S L2 S L1 S R1 S R2 S R1 When in a non-conducting state, diode D3 in the third diode circuit D3 i D32, D31 allow unidirectional current flow from the center node Nc of the first series connection SC1 to the first terminal T1 for charging the first capacitor C1 and the second capacitor C2. Figure 5 As shown, diode D3 in the third diode circuit D3 i ..., D32, D31 and diode D1 of the first diode circuit D1 i ..., D12, D11 anti-parallel arrangement.

[0200] Figure 5 The switching device 1 includes a fourth diode circuit D4 electrically connected between the second terminal T2 and node N1 between the first capacitor C1 and the first diode circuit D1. The fourth diode circuit D4 also includes an even number (2*i) of switches S1, the number of which is equal to the number of switches S1 connected in series with the first diode circuit SC1.Li S L2 S L1 S R1 S R2 S Ri Half of the diodes. That is, the fourth diode circuit D4 includes at least one diode.

[0201] In the case where the fourth diode circuit D4 includes two or more diodes, the diodes are connected in series. For example... Figure 5 As shown, the diodes D41, D42, ..., D4 in the fourth diode circuit D4 i They are connected in series, so that each diode D41, D42, ..., D4... i The cathode of the first diode circuit D4 points to the center node Nc of the first series connection SC1, and thus to the first capacitor C1. In other words, diodes D41, D42, ..., D4 of the fourth diode circuit D4... i The electrical connection allows the cathode of the fourth diode circuit D4 to be electrically connected to the anode of another diode (as is the case with diodes D41 and D42) or electrically connected to the first capacitor C1 (as is the case with diode D41). Therefore, when the switch S of the first series-connected SC1... Li S L2 S L1 S R1 S R2 S Ri When in the non-conducting state, diodes D41, D42, ..., D4 in the fourth diode circuit D4 i Unidirectional current flow is permitted for the charging current used to charge the first capacitor C1 and the second capacitor C2, from the second terminal T2 to the center node Nc of the first series connection SC1. For example... Figure 5 As shown, the diodes D41, D42, ..., D4 in the fourth diode circuit D4 i With the second diode circuit D2, diodes D21, D22, ..., D2 i Anti-parallel arrangement.

[0202] like Figure 5 As shown, for each node N[i-1] between the two diodes in the third diode circuit D3 and between the two diodes in the fourth diode circuit D4 D3 , ..., N1 D3 N1 D4 ,…,N[i-1] D4 The switching device 1 may also include an optional third capacitor C3. Each node (e.g., node N1) between the two diodes of the third diode circuit D3. D3The first part P1 of the first series connection SC1 is electrically connected via a corresponding third capacitor C3 to the node between the two switches of the first switch (e.g., node N1) between the first terminal T1 and the center node Nc of the first series connection SC1. L ), such that the corresponding node between the two diodes (e.g., node N1) D3 The node (e.g., node N1) between the two switches in the first part P1 of the first series connection SC1. L The diode D3 is placed at the same position as the diode in the third diode circuit D3. i In the series connection of diodes D1, D2, D32, D31, the corresponding node between the two diodes (e.g., node N1) D3 Electrically connected to the node between the two switches (e.g., node N1) L ).

[0203] Each node between the two diodes in the fourth diode circuit D4 (e.g., node N1) D4 The first series connection SC1 is electrically connected via a corresponding third capacitor C3 to the node between the two switches of the second part P2 of the first series connection SC1, which is the center node Nc of the first series connection SC1 and the second terminal T2. (e.g., node N1) R ), such that the corresponding node between the two diodes (e.g., node N1) D4 The node (e.g., node N1) between the two switches in the second part P2 of the first series connection SC1. R Diodes D41, D42, ..., D4 are arranged at the same positions in the fourth diode circuit D4. i In a series connection, the corresponding node between the two diodes (e.g., node N1) D4 Electrically connected to the node between the two switches (e.g., node N1) R ).

[0204] Based on the above, Figure 5 The number of switches, diodes, and third capacitor C3 shown is merely an example and does not limit this disclosure.

[0205] Figure 6 and Figure 7 An embodiment of the switching device according to the first aspect and an embodiment of the switching device according to the eighth aspect are shown.

[0206] Therefore, the above descriptions of the switching device in the first aspect and the switching device in the eighth aspect are for Figure 6 and Figure 7 The corresponding switching device is effective.

[0207] Figure 6 and Figure 7 The switching device corresponds to Figure 5 The switching device, wherein, Figure 6 (a) The even number of switches S in the first series connection of the switching device SC1 L1 S R1 The quantity is equal to two, and Figure 6 (b) The even number of switches S in the first series connection of the switching device SC1 L2 S L1 S R1 S R2 The quantity is four. Figure 7 The even number of switches S in the first series connection of the switching device SC1 L3 S L2 S L1 S R1 S R2 S R3 The quantity is equal to six. Therefore, Figure 5 The above description of the switching device corresponds to... Figure 6 and Figure 7 The switching device is effective, and for the description Figure 6 and Figure 7 Switching device, reference Figure 2 and Figure 5 The above description.

[0208] Figure 8 An embodiment of the invention is shown. Figure 3 The switching state of the switching device when switching between the on and off states.

[0209] exist Figure 8 , Figure 9 and Figure 10 In the diagram, a switch in a non-conducting state is represented by a dashed line. Furthermore, in... Figure 8 , Figure 9 and Figure 10 In the diagram, the current flow through the switching device is indicated by arrows.

[0210] In order to describe Figure 8 The function of switching device 1 is assumed to be that a voltage source VS providing a positive voltage Vin is connected to the first terminal T1 of switching device 1, and the load R L (Example: by load resistance R) L (Indicates) connected to the second terminal T2, such as Figure 8 As shown in (a). This is for descriptive purposes only. Figure 8 This is an example of the function of the switching device 1 and does not limit the scope of this disclosure. The positive voltage Vin can be, for example, 1000 volts (e.g., Vin = 1000V). In other words, suppose the switching device 1 is used to apply the positive voltage Vin of the voltage source VS to the load R.L (In the ON state of switch 1, where Vout = Vin) and used to interrupt the application of the positive voltage Vin of voltage source VS to load R. L (In the non-conducting state of switching device 1, no current flows through the load R via switching device 1) L And therefore Vout = 0V). The voltage at the second terminal T2 corresponds to the load R. L The voltage across the two ends can be called the output voltage Vout of the switching device 1.

[0211] exist Figure 8 In (a), the switching device is shown in a non-conducting state, that is, the two switches S of the switching device 1 (the first series connection of SC1) are shown in a non-conducting state. L1 and S R1 It is in a non-conducting state. Therefore, no current (load current) flows from the first terminal T1 through the switch S. L1 and S R1 The current flows to the second terminal T2. Therefore, it is in the... Figure 8 The switching device 1 in the state shown in (a) corresponds to a single semiconductor switch, specifically a unidirectional switch, i.e., in a non-conducting state, and therefore no current path is provided between its two terminals T1 and T2. Therefore, the positive voltage Vin of the voltage source VS exists at the switch S of the switching device 1. L1 and S R1 The first series connection is between the two ends (i.e., the voltage between the two terminals T1 and T2 is equal to Vin).

[0212] like Figure 8 As shown in (a), diode D11 of the first diode circuit D1 and diode D21 of the second diode circuit provide current paths for the charging current of the first capacitor C1 and the second capacitor C2. Therefore, when the two switches S L1 and S R1 When in the non-conducting state, current can flow through diode D11 of the first diode circuit D1 and diode D21 of the second diode circuit D2, ensuring that capacitors C1 and C2 are charged to voltage Vin. That is, first capacitor C1 and second capacitor C2 are each charged to half of the positive voltage Vin (V0). C1 =V C2 =Vin / 2). Once capacitors C1 and C2 are charged to voltage Vin (V C1 +V C2=Vin), diode D11 of the first diode circuit D1 is reverse biased. That is, once capacitors C1 and C2 are charged, the current flow through diode D11 of the first diode circuit D1 and diode D21 of the second diode circuit D2 stops. Since capacitors C1 and C2 are each charged to half of voltage Vin, switch S L1 voltage and switch S R1 The voltage across the switch is equal to half the voltage Vin. Therefore, voltage balance is achieved through capacitors C1 and C2. In other words, the positive voltage Vin is evenly distributed across switch S. L1 and S R1 Above. Capacitors C1 and C2 are used to measure the intermediate voltage value of the output voltage Vout during transient states (very short, such as lasting tens or hundreds of nanoseconds) between the output voltage values ​​in the non-conducting and conducting states.

[0213] In order to switch the switching device 1 from the non-conducting state to the as-conducting state Figure 8 (d) shows the conducting state, and the switch S of the switching device 1 L1 and S R1 The circuit sequentially switches from the non-conducting state to the conducting state. This can be done by first switching the switch S connected to the first terminal T1. L1 Or the switch S connected to the second terminal T2 R1 In the case of more than two switches, the switches can be switched sequentially according to the order of their first series connection. That is, in order to... Figure 3 and Figure 8 Switching device 1 switches from a non-conducting state to a conducting state, and switching device 1 in Figure 8 (b) and Figure 8 (c) operates in a transient state, where only switch S is active. L1 and S R1 One of the switches is switched to the ON state (closed respectively).

[0214] exist Figure 8 In the transient state shown in (b), current flows from the first terminal T1 through the first capacitor C1 and the switching switch S. R1 The current flows to the second terminal T2. When the switch S is turned on... R1 When in the ON state, it corresponds to a short circuit; therefore, switch S R1 The voltage is equal to 0 volts. As a result, the second capacitor C2 discharges, and the output voltage Vout is equal to half of the positive voltage Vin (Vout = Vin / 2). Figure 8 In the transient state shown in (c), current flows from the first terminal T1 through the on switch S L1 And the current flows from the second capacitor C2 to the second terminal T2. When the switch S is turned on...L1 When in the ON state, it corresponds to a short circuit; therefore, switch S L1 The voltage is equal to 0 volts. As a result, the first capacitor C1 discharges, and the output voltage Vout is equal to half of the voltage Vin (Vout = Vin / 2).

[0215] In order to achieve Figure 8 (d) shows the on state of the switching device, and the corresponding other switches switch from the off state to the on state. That is, in order to switch from the on state to the off state... Figure 8 (b) shows the transient state to the conduction state of switching device 1, switch S L1 It was switched to the on state. Therefore, in order to... Figure 8 (c) shows the transient state to the conduction state of switching device 1, switch S R1 The switches are switched to the ON state. In the ON state, all switches S of switching device 1... L1 S R1 It is in the ON state, therefore, switch S L1 and S R1 The voltages of all devices are 0 volts, and the output voltage Vout of the switching device 1 is equal to the positive voltage Vin of the voltage source VS (Vout = Vin).

[0216] In order to switch the switch from the on state to the off state, the switch S of the switching device 1 L1 and S R1 It also switches sequentially from the ON state to the OFF state. The switch S connected to the first terminal T1 can be switched first. L1 Or the switch S connected to the second terminal T2 R1 In the case of more than two switches, the switches can be switched sequentially according to the order of their first series connection. That is, in order to... Figure 3 and Figure 8 Switching device 1 switches from the conducting state to the non-conducting state, and switching device 1 in Figure 8 (b) and Figure 8 (c) operates in a transient state, where only switch S is active. L1 and S R1 One of the switches is switched to the non-conducting state (disconnected).

[0217] To switch the switching device from the ON state to the OFF state, the switch S is first turned on. L1 Switching from the on state to the off state (e.g.) Figure 8 (b) As shown, current flows from the first terminal T1 through the first capacitor C1 and the still-conducting switch S. R1 The current flows to the second terminal T2. As a result, the first capacitor C1 is charged to half of the voltage Vin (V). C1=Vin / 2), non-conducting switch S L1 The voltage is equal to half of the voltage Vin, and the output voltage Vout drops to half of the voltage Vin (Vout = Vin / 2). When switching the device from the ON state to the OFF state, the switch S is first turned... R1 Switching from the on state to the off state (e.g.) Figure 8 (c) As shown, current flows from the first terminal T1 through the still-conducting switch S L1 The current flows from the second capacitor C2 to the second terminal T2. As a result, the second capacitor C2 is charged to half of the voltage Vin (V). C2 =Vin / 2), non-conducting switch S R1 The voltage is equal to half of the voltage Vin, and the output voltage Vout is reduced to half of the voltage Vin (Vout = Vin / 2).

[0218] In order to achieve Figure 8 (a) shows the switching device in its non-conducting state; correspondingly, other switches switch from the conducting state to the non-conducting state. That is, in order to... Figure 8 (b) The transient state shown in the diagram transitions to the non-conducting state of the switching device 1, and the switch S R1 It was switched to a non-conducting state. Therefore, in order to... Figure 8 (c) shows the transient state to the non-conducting state of switching device 1, switch S L1 The switches are switched to the non-conducting state. In the non-conducting state, all switches S of switching device 1 L1 S R1 Since they are in a non-conducting state, the first capacitor C1 and the second capacitor C2 are each charged to half of the voltage Vin of the voltage source VS (V0). C1 =V C2 =Vin / 2). As a result, switch S L1 and S R1 The voltages are all equal to half of the voltage Vin, and the output voltage Vout of switching device 1 is equal to 0 volts (Vout=0V).

[0219] Figure 9 and Figure 10 Each of the embodiments of the present invention is shown to be... Figure 6 (a) The switching state when the switching device switches between the on state and the off state.

[0220] Figure 9 (a) shows the non-conducting state of the switching device 1. Figure 9 (b) and Figure 9 (c) shows two possible transient states of the switching device 1. Figure 9(d) shows the on state of the switching device 1. In the on state, current flows from the first terminal T1 through the bidirectional switch S. L1 and S R1 The current flows to the second terminal T2 of the switching device 1. Therefore, it can be assumed that the voltage source VS, which provides the positive voltage Vin, is connected to the first terminal T1, and the load R... L Connect to the second terminal T2, such as Figure 9 As shown in (a). The positive voltage Vin can be, for example, 1000 volts (e.g., Vin = 1000V). Therefore, in the non-conducting state and in both possible transient states, current can flow through diode D11 of the first diode circuit D1 and diode D21 of the second diode circuit D2. Figure 8 The above description is for describing Figure 9 The four states of the switch device 1 shown are correspondingly valid.

[0221] Figure 10 (a) shows the non-conducting state of the switching device 1. Figure 10 (b) and Figure 10 (c) shows two possible transient states of the switching device 1. Figure 10 (d) shows the on state of the switching device 1. In the on state, current flows from the second terminal T2 through the bidirectional switch S. R1 and S L1 The current flows to the first terminal T1 of the switching device 1. Therefore, it can be assumed that the voltage source VS providing the negative voltage -Vin is connected to the first terminal T1, and the load R... L Connect to the second terminal T2, such as Figure 10 As shown in (a). The negative voltage -Vin can be, for example, -1000 volts (e.g., Vin = -1000V). This is equivalent to connecting the voltage source VS to the second terminal T2 of the switching device 1, where the voltage source VS provides the positive voltage Vin. Therefore, in the non-conducting state and in both possible transient states, current can flow through diode D31 of the third diode circuit D3 and diode D41 of the fourth diode circuit D4. Figure 8 The above description is for describing Figure 10 The four states of the switch device 1 shown are correspondingly valid.

[0222] Figure 11 An embodiment of the invention is shown. Figure 6 (a) Figure 9 and Figure 10 The voltage curve of the switching device as it switches between the on and off states over time.

[0223] Figure 8 The above description is for describing Figure 11The states (1) to (10) of the switch device 1 shown are correspondingly active. Regarding Figure 6 (a) the switching device, Figure 11 The graph at the top shows switch S L1 voltage and switch S R1 Voltage change over time ( Figure 6 (a) Switch S of the switching device L1 and S R1 Corresponding to Figure 3 Switch S of the switching device L1 and S R1 "Voltage of the switch" and "voltage across the switch" can be used as synonyms. That is to say, Figure 11 The graph at the top shows switch S L1 and S R1 The voltage across the terminals changes over time. Figure 11 The graph at the bottom shows the corresponding output voltage Vout. Figure 11 The graph in (a) shows when Figure 6 (a) The switching device is used to provide, in the on state, as Figure 9 The diagram shows the connection from the first terminal T1 via switch S. L1 and S R1 The case where the current path leads to the second terminal T2. Figure 11 (b) The graph shows when Figure 6 (a) The switching device is used to provide, in the on state, as Figure 10 The diagram shows the connection from the second terminal T2 via switch S. R1 and S L1 The case where the current path leads to the first terminal T1.

[0224] Figure 11 Region (1) of (a) corresponds to the non-conducting state (e.g., Figure 9 (a) shows that switch S L1 and S R1 The voltage is equal to half of the voltage Vin, and the output voltage Vout is equal to 0 volts (it can be assumed that the voltage source providing the positive voltage Vin is connected to the first terminal T1). That is, in region (1), the voltage Vin is equal to half of the voltage at switch S. L1 and S R1 The current is evenly distributed between the two sides, and no current flows through switch S. L1 and S R1 This results in an output voltage of 0 volts (Vout = 0V). The voltage Vin can be, for example, 1000 volts, but this is only an example and does not limit this disclosure. Figure 11 (a) region (2) corresponds to when switch S R1 First, the transient state of the switching device when switching from a non-conducting state to a conducting state (e.g.) Figure 9 (b) shown). Therefore, in region (2), switch S R1 The voltage drops to 0 volts, and the output voltage Vout increases to half the voltage Vin (Vout = Vin / 2). After a short delay, switch S... L1 Switching to the ON state, therefore, switch S L1 When the voltage drops to 0 volts, the output voltage Vout increases to the full voltage Vin (Vout = Vin), such as Figure 11 (a) is shown in region (3). Therefore, region (3) corresponds to the on state of the switching device (as shown in region (a)). Figure 9 (d) shows. Therefore, regions (1) to (3) show when Figure 6 (a) The switching device is switched from the non-conducting state via Figure 9 When the transient state shown in (b) switches to the on state, switch S L1 and S R1 The voltage and the output voltage Vout.

[0225] Figure 11 (a) region (4) corresponds to when switch S R1 First, the transient state of the switching device when switching from the on state to the off state (e.g.) Figure 9 (c) shown). Therefore, in region (4), switch S R1 The voltage increases to half of the voltage Vin, and the output voltage Vout decreases to half of the voltage Vin (Vout = Vin / 2). After a short delay, switch S... L1 Switching to the non-conducting state, therefore, switch S L1 When the voltage is increased to half of the voltage Vin, the output voltage Vout increases to 0 volts (Vout = 0V). Figure 11 (a) is shown in region (5). Therefore, region (5) again corresponds to the non-conducting state of the switching device (as shown in region (a)). Figure 9 (a) is shown). Therefore, regions (3) to (5) show when Figure 6 (a) The switching device is switched from the on state via Figure 9 When the transient state shown in (b) switches to the non-conducting state, switch S L1 and S R1 The voltage and the output voltage Vout.

[0226] Figure 11 (b) shows Figure 6 (a) the switching device and Figure 11The same behavior is shown in (a) for the case where a voltage source VS providing a negative voltage -Vin is connected to the first terminal T1 of the switching device. This is equivalent to connecting the voltage source VS to the second terminal T2 of the switching device, where the voltage source VS provides a positive voltage Vin. Figure 11 (b) Switching order and Figure 11 The difference in the switching sequence of (a) is that the switching device moves from the non-conducting state via Figure 9 (c) shows the transient state switching to the on state, and from the on state via Figure 9 (b) shows the transient state switching to the non-conducting state.

[0227] Figure 12 An embodiment of the invention is shown. Figure 6 (b) Voltage curves over time as the switching device switches between the on and off states.

[0228] Figure 8 , Figure 9 , Figure 10 and Figure 11 The above description is for describing Figure 12 (a) and Figure 12 (b) The states (1) to (9) of the switching device 1 shown are correspondingly active. Regarding Figure 6 (b) the switching device, Figure 12 The graph at the top shows switch S L2 S L1 S R1 S R2 The voltage changes over time. Figure 12 The graph at the bottom shows the corresponding output voltage Vout. Figure 12 The graph in (a) shows when Figure 6 (b) The switching device is used to provide power from the first terminal T1 via switch S in the on state. L2 S L1 S R1 S R2 The current path to the second terminal T2 is as follows: Figure 6 (a) Switching device Figure 11 As shown in (a). Figure 12 (b) The graph shows when Figure 6 (b) The switching device is used to provide power from the second terminal T2 via switch S in the on state. R2 S R1 S L1 S L2 The current path to the first terminal T1 is as follows: Figure 6 (a) Switching device Figure 11 As shown in (b).

[0229] Figure 12 Regions (1) and (9) in (a) correspond to Figure 6 (b) is the non-conducting state of the switching device, therefore corresponding to Figure 11 (a) Regions (1) and (5). Figure 12 Region (5) of (a) corresponds to Figure 6 (b) The conducting state of the switching device, therefore corresponding to Figure 11 (a) of region (3).

[0230] When the switching device switches from a non-conducting state to a conducting state Figure 12 Regions (2), (3), and (4) of (a) correspond to Figure 6 (b) The transient state of the switching device. Figure 12 (a) region (1) to region (5), in order to Figure 6 (b) The switching device switches from the non-conducting state to the conducting state, according to switch S L2 S L1 S R1 S R2 The sequence of series connections, switch S L2 S L1 S R1 S R2 The switches are sequentially switched from a non-conducting state to a conducting state (with a brief delay of, for example, tens or hundreds of nanoseconds), wherein the switch S connected to the first terminal T1 of the switching device is switched first. L2 Switching from non-conducting state to conducting state ( Figure 12 (a) region (2)). Thus, in Figure 12 In region (3) of (a), switch S L1 (It is switch S in the series connection of switches) L2 The successive switches are switched to the ON state, in Figure 12 In region (4) of (a), switch S R1 (It is switch S in the series connection of switches) L1 The successive switches are switched to the ON state, and... Figure 12 In region (5) of (a), switch S R2 (It is switch S in the series connection of switches) R1 The successive switches were switched to the on state.

[0231] When the switching device switches from the on state to the off state... Figure 12 Regions (6), (7), and (8) of (a) correspond to Figure 6 (b) The transient state of the switching device. Figure 12 (a) region (5) to region (9), in order to Figure 6 (b) The switching device switches from the on state to the off state, according to switch S L2 S L1 S R1 S R2 The sequence of series connections, switch S L2 S L1 S R1 S R2 The switches are sequentially switched from the on state to the off state (with a brief delay of, for example, tens or hundreds of nanoseconds), wherein the switch S connected to the first terminal T1 of the switching device is switched first. L2 Switching from the on state to the off state ( Figure 12 (a) region (6)). Thus, in Figure 12 In region (7) of (a), switch S L1 (It is switch S in the series connection of switches) L2 The successive switches are switched to the non-conducting state, in Figure 12 In region (8) of (a), switch S R1 (It is switch S in the series connection of switches) L1 The successive switches are switched to the non-conducting state, and... Figure 12 In region (9) of (a), switch S R2 (It is switch S in the series connection of switches) R1 The successive switches were switched to the non-conducting state.

[0232] Figure 12 (b) shows Figure 6 (b) the switching device and Figure 12 The same behavior is shown in (a) for the case where a voltage source VS providing a negative voltage -Vin is connected to the first terminal T1 of the switching device. This is equivalent to connecting the voltage source VS to the second terminal T2 of the switching device, where the voltage source VS provides a negative voltage -Vin. Figure 12 (b) Switching order and Figure 12 The difference in the switching sequence of (a) is that, in order to switch the switching device from the non-conducting state to the conducting state ( Figure 12 (b) region (1) to region (5) and the switch from the conducting state to the non-conducting state ( Figure 12 (b) Regions (5) to (9) are connected to the switch S connected to the second terminal T2. R2 Start switching, and then continue switching according to the order of the switches in the series connection.

[0233] like Figure 11 and Figure 12As shown, the number of transient states between the on and off states is one less than the number of switches in the switching device. Therefore, the number of intermediate voltage values ​​of the output voltage Vout between the output voltage Vout value in the off state (Vout = 0V) and the output voltage Vout value in the on state (Vout = Vin or -Vin) is one less than the number of switches in the switching device.

[0234] Figures 13 to 16 A converter system and converter according to an embodiment of the present invention are shown.

[0235] Figure 13 An embodiment of the converter system according to the third aspect is shown. Therefore, the above description of the converter system with respect to the third aspect is relevant to... Figure 13 The converter system is therefore effective.

[0236] like Figure 13 As shown in (a), a converter system 2 according to an embodiment of the present disclosure includes a converter 3. The converter 3 may be an AC / DC converter, a DC / AC converter, a DC / DC converter, or an AC / AC converter. Specifically, the converter 3 may be a T-type converter, such as a 3-stage T-type converter; a nested T-type converter, such as a 3-stage nested T-type converter or a 5-stage nested T-type converter; a monkey head converter; a Vienna converter / rectifier; or a matrix converter. The converter 3 may be implemented according to other power electronic converter topologies known to those skilled in the art. The converter 3 of the converter system may include one or more switching devices 1 for controlling the power conversion of the converter 3.

[0237] One or more switching devices 1 may correspond to one or more switching devices of the first aspect or any implementation thereof, one or more switching devices of the eighth aspect or any implementation thereof, one or more switching devices of the ninth aspect or any implementation thereof, and / or one or more switching devices of the tenth aspect or any implementation thereof. Therefore, one or more switching devices 1 may correspond to... Figures 1 to 7 Any of the switching devices shown. The converter system 2 may also include more than one converter 3. The foregoing applies accordingly to multiple converters 3 of the converter system 2.

[0238] Figure 13 (b) The converter system corresponds to Figure 13 (a) The converter system. Therefore, the above regarding Figure 13 The description of the converter system in (a) also applies. Figure 13 (b) The converter system. Figure 13(b) The converter system 2 further includes a control unit 4. The control unit 4 is used to control the power conversion of at least one converter 3 by performing the method of the second aspect or any implementation thereof, for switching one or more switching devices 1 of at least one converter 3 between an on state and an off state. Therefore, the control unit 4 can be used to control the switching of one or more switching devices 1 of at least one converter 3, as described above regarding... Figures 1 to 12 As described.

[0239] The control unit 4 may include or correspond to a processor, microprocessor, controller, microcontroller, field programmable gate array (FPGA), application specific integrated circuit (ASIC), or any combination thereof.

[0240] Figures 14 to 16 It shows Figure 13 An embodiment of at least one converter 3 of the converter system.

[0241] Figure 14 The Vienna converter 3 is shown, wherein each of the bidirectional switches bS1, bS2, and bS3 can correspond to a switching device according to the first aspect or any implementation thereof, wherein the switch of the switching device is a bidirectional switch. Alternatively, each of the bidirectional switches bS1, bS2, and bS3 can correspond to a switching device according to the eighth aspect or any implementation thereof, wherein the switch of the switching device is a bidirectional switch. Specifically, each of the bidirectional switches bS1, bS2, and bS3 can be made according to... Figure 5 , Figure 6 (a) Figure 6 (b) and Figure 7 One of the switching devices is implemented. At least one of the bidirectional switches bS1, bS2 and bS3 can be implemented differently compared to other switches.

[0242] Figure 15 A three-stage nested T-type converter 3 is shown. The bidirectional switch bS11 of the three-stage nested T-type converter 3 can be as described above regarding... Figure 14 The bidirectional switches bS1, bS2, and bS3 of the Vienna converter 3 are implemented as described above. The unidirectional switches uS11, uS12, uS13, and uS14 can be implemented by a single unidirectional switch, for example, as... Figure 1As shown. Alternatively or additionally, at least one of the one-way switches uS11, uS12, uS13, and uS14, in particular all of the switches, can be implemented by a switching device according to the first aspect or any implementation thereof, wherein at least one switch of the switching device is a one-way switch, or the switch of the switching device is a one-way switch. Alternatively or additionally, at least one of the one-way switches uS11, uS12, uS13, and uS14, in particular all of the switches, can be implemented by a switching device according to the eighth aspect or any implementation thereof, the ninth aspect or any implementation thereof, or the tenth aspect or any implementation thereof, wherein at least one switch of the switching device is a one-way switch, or the switch of the switching device is a one-way switch. Specifically, each of the one-way switches uS11, uS12, uS13, and uS14 can be implemented by a switching device according to the first aspect or any implementation thereof. Figure 2 , Figure 3 , Figure 4 (a) and Figure 4 (b) is implemented using one of the switching devices. At least one of the unidirectional switches uS11, uS12, uS13 and uS14 may be implemented differently from the other switches.

[0243] Figure 16 A 5-stage nested T-type converter 3 is shown. The bidirectional switches bS21 and bS22 of the 5-stage nested T-type converter 3 can be configured as described above. Figure 14 The bidirectional switches bS1, bS2, and bS3 of the Vienna converter 3 are implemented as described above. The unidirectional switches uS21, uS22, uS23, uS24, uS25, uS26, uS27, and uS28 can be implemented as described above. Figure 15 The unidirectional switches uS11, uS12, uS13 and uS14 of the 3-level nested T-type converter are implemented as described.

[0244] Figure 15 and Figure 16 The voltages shown are merely examples and do not limit this disclosure.

[0245] This disclosure has been described in conjunction with various embodiments and implementations as examples. However, other variations can be understood and implemented by those skilled in the art and by practicing the claimed invention, through a study of the drawings, this disclosure, and the independent claims. In the claims and the description, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude multiple. A single element or other unit can perform the function of several entities or items recited in the claims. The fact that certain means are recited in mutually different dependent claims does not mean that a combination of these means cannot be used for advantageous implementation.

Claims

1. A switching device (1) for a converter, wherein, The switching device (1) includes: At least two switches (S) between the two terminals (T1, T2) of the switching device (1) L1 S R1 The first series connection (SC1) of the two switches (S) L1 S R1 () is a semiconductor switch; The first capacitor (C1) and the first diode circuit (D1) are connected in a second series connection (SC2), which is electrically connected in parallel with the first part (P1) of the first series connection (SC1). The first part (P1) of the first series connection (SC1) is located at the first terminal (T1) of the two terminals (T1, T2) and the two switches (S). L1 S R1 Between nodes (Nc) between the first diode circuit (D1), the first diode circuit (D1) includes at least one diode (D11); and The second capacitor (C2) and the second diode circuit (D2) are connected in a third series connection (SC3), which is electrically connected in parallel with the second part (P2) of the first series connection (SC1). The second part (P2) of the first series connection (SC1) is located at the second terminal (T2) of the two terminals (T1, T2) and the two switches (S). L1 S R1 Between the nodes (Nc) between the second diode circuit (D2), wherein the second diode circuit (D2) includes at least one diode (D21); The switching device is used to implement quasi-multilevel operation to improve the effective voltage capability between the two terminals (T1, T2). The quasi-multilevel operation is achieved by switching the at least two switches between an on state and an off state via at least one transient state, which is generated by sequentially switching the at least two switches.

2. The switching device (1) according to claim 1, wherein, The first series connection (SC1) includes an even number of switches (S) of four or more. Li S L2 S L1 S R1 S R2 S Ri ), wherein the switch (S) Li S L2 S L1 S R1 S R2 S Ri () is a semiconductor switch; The second series connection (SC2) and the third series connection (SC3) are each electrically connected to the node (Nc) at the center of the first series connection (SC1), and the node is the center node (Nc) of the first series connection (SC1); The first capacitor (C1) of the second series connection (SC2) and the second capacitor (C2) of the third series connection (SC3) are electrically connected to the center node (Nc) of the first series connection (SC1); The first diode circuit (D1) and the second diode circuit (D2) each include an even number of the switches (S). Li S L2 S L1 S R1 S R2 S Ri Half of the diode; and Each diode (D11, D12, D13) in the first diode circuit (D1) and the second diode circuit (D2) i D21, D22, D2 i They are connected in series.

3. The switching device (1) according to claim 1, wherein, The switching device (1) includes a third diode circuit (D3) and a fourth diode circuit (D4), each of which includes at least one diode (D31; D41). The first capacitor (C1) of the second series connection (SC2) and the second capacitor (C2) of the third series connection (SC3) are electrically connected to the node (Nc) between the two switches; The third diode circuit (D3) is electrically connected between the first terminal (T1) and the node (N2), and the node (N2) is located between the second capacitor (C2) and the second diode circuit (D2); The fourth diode circuit (D4) is electrically connected between the second terminal (T2) and the node (N1), and the node (N1) is located between the first capacitor (C1) and the first diode circuit (D1); At least one diode (D31) of the third diode circuit (D3) is arranged in anti-parallel with at least one diode (D11) of the first diode circuit (D1); and At least one diode (D41) of the fourth diode circuit (D4) is arranged in antiparallel with at least one diode (D21) of the second diode circuit (D2).

4. The switching device (1) according to claim 3, wherein, The first series connection (SC1) includes an even number of switches (S) of four or more. Li S L2 S L1 S R1 S R2 S Ri ), wherein the switch (S) Li S L2 S L1 S R1 S R2 S Ri () is a semiconductor switch; The second series connection (SC2) and the third series connection (SC3) are each electrically connected to the node (Nc) at the center of the first series connection (SC1), and the node is the center node (Nc) of the first series connection (SC1); The first capacitor (C1) of the second series connection (SC2) and the second capacitor (C2) of the third series connection (SC3) are electrically connected to the center node (Nc) of the first series connection (SC1); The first diode circuit (D1), the second diode circuit (D2), the third diode circuit (D3), and the fourth diode circuit (D4) each include an even number of the switches (S). Li S L2 S L1 S R1 S R2 S Ri Half of the diodes; and Each diode (D11, D12, D13) in the first diode circuit (D1), the second diode circuit (D2), the third diode circuit (D3), and the fourth diode circuit (D4) i D21, D22, D2 i D31, D32, D3 i D41, D42, D4 i They are connected in series.

5. The switching device (1) according to claim 3 or 4, wherein, For each node (N1) between the two diodes of the first diode circuit (D1), between the two diodes of the second diode circuit (D2), and between the two diodes of the optional third diode circuit (D3), and between the two diodes of the fourth diode circuit (D4). D1 , N[i-1] D1 N1 D2 , N[i-1] D2 N1 D3 , N[i-1] D3 N1 D4 , N[i-1] D4 The switching device (1) includes a third capacitor (C3); The nodes (N1) between the two diodes of the first diode circuit (D1) and between the two diodes of the optional third diode circuit (D3) D 1, N[i-1] D1 N1 D3 , N[i-1] D3 The node (N1) between the two switches in the first part (P1) of the first series connection (SC1) is electrically connected via the corresponding third capacitor (C3). L , N[i-1] L The corresponding nodes between the two diodes are arranged in the series connection of the diodes in the corresponding diode circuit (D1; D3) at the same position as the nodes between the two switches in the first part (P1) of the first series connection (SC1), and the corresponding nodes between the two diodes are electrically connected to the nodes between the two switches; the first part (P1) of the first series connection (SC1) is located between the first terminal (T1) and the center node (Nc) of the first series connection (SC1); and Each node (N1) between the two diodes of the second diode circuit (D2) and between the two diodes of the optional fourth diode circuit (D4) D2 , N[i-1] D2 N1 D4 , N[i-1] D4 The node (N1) between the two switches in the second part (P2) of the first series connection (SC1) is electrically connected via the corresponding third capacitor (C3). R , N[i-1] R The corresponding nodes between the two diodes are arranged in the series connection of the diodes in the corresponding diode circuit (D2; D4) at the same position as the nodes between the two switches in the second part (P2) of the first series connection (SC1), and the corresponding nodes between the two diodes are electrically connected to the nodes between the two switches. The second part (P2) of the first series connection (SC1) is located between the center node (Nc) of the first series connection (SC1) and the second terminal (T2).

6. The switching device (1) according to any one of claims 1-4, wherein, The first capacitor (C1) and the second capacitor (C2) have the same capacitance.

7. The switching device (1) according to any one of claims 1-4, wherein, A third capacitor (C3) electrically connected to the same node between the two switches in the first series connection (SC1) has the same capacitance.

8. The switching device (1) according to any one of claims 1-4, wherein, The diodes (D11, D12, D13) of the switching device (1) i D21, D22, D2 i ; D31, D32, D3 i D41, D42, D4 i ) is used for: when all switches (S) Li S L2 S L1 S R1 S R2 S Ri When in a non-conducting state, it provides a current path for the charging current used to charge the first capacitor (C1) and the second capacitor (C2).

9. The switching device (1) according to any one of claims 2-4, wherein, In order to switch the switching device (1) between an on state and a non-on state, the switch (S) Li S L2 S L1 S R1 S R2 S Ri ) is used to be controlled such that the switch (S) Li S L2 S L1 S R1 S R2 S Ri At least two switches in the circuit will not switch between the on state and the off state simultaneously.

10. The switching device (1) according to any one of claims 2-4, wherein, In order to switch the switching device (1) between an on state and a non-on state, the switch (S) Li S L2 S L1 S R1 S R2 S Ri ) is used to be controlled such that the switch (S) Li S L2 S L1 S R1 S R2 S Ri According to the order in the first series connection (SC1), the system switches between the on state and the off state in sequence.

11. The switching device (1) according to any one of claims 2-4, wherein, In order to switch the switching device (1) between an on state and a non-on state, the switch (S) Li S L2 S L1 S R1 S R2 S Ri The switch is controlled such that one of the switches electrically connected to one of the two terminals (T1, T2) first switches between the on state and the off state.

12. The switching device (1) according to any one of claims 2-4, wherein, In the case where the first series connection comprises an even number of switches of four or more: In terms of nodes, two switches equidistant from the central node (Nc) of the first series connection (SC1) are switch pairs, such that the first series connection (SC1) includes multiple switch pairs; and In order to switch the switching device (1) between an on state and a non-on state, the switch (S) Li S L2 S L1 S R1 S R2 S Ri ) is used to be controlled so that: At least one switch pair of the plurality of switch pairs simultaneously switches between the on state and the off state, and The two switches of each of the other switch pairs of the plurality of switch pairs are switched sequentially.

13. The switching device (1) according to claim 12, wherein, In order to switch the switching device (1) between the on state and the off state, the switch (S) Li S L2 S L1 S R1 S R2 S Ri ) is used to be controlled so that: The two switches of each of the plurality of switch pairs switch simultaneously between the on state and the off state, wherein at least two switch pairs of the plurality of switch pairs do not switch simultaneously between the on state and the off state.

14. The switching device (1) according to claim 12, wherein, In order to switch the switching device (1) from the conducting state to the non-conducting state, the switch (S Li S L2 S L1 S R1 S R2 S Ri ) is used to be controlled so that: Includes two switches (S) electrically connected to the two terminals (T1, T2) of the switching device (1). Li S Ri The switch pair or includes two switches (S) electrically connected to the center node (Nc) of the first series connection (SC1). L1 S R1 The switch pair of the plurality of switch pairs first switches from the conducting state to the non-conducting state, and the other switch pairs of the plurality of switch pairs sequentially switch from the conducting state to the non-conducting state according to the order of the other switch pairs in the first series connection (SC1); and In order to switch the switching device (1) from the non-conducting state to the conducting state, the switch (S) Li S L2 S L1 S R1 S R2 S Ri ) is used to be controlled so that: The two switches (S) are included, which are electrically connected to the two terminals (T1, T2) of the switching device (1). Li S Ri The switch pair or includes the two switches (S) electrically connected to the center node (Nc) of the first series connection (SC1). L1 S R1 The switch pair of the plurality of switches first switches from the non-conducting state to the conducting state, and the other switch pairs of the plurality of switch pairs switch from the non-conducting state to the conducting state in sequence according to the order of the other switch pairs in the first series connection (SC1).

15. The switching device (1) according to claim 12, wherein, In order to switch the switching device (1) from the conducting state to the non-conducting state and from the non-conducting state to the conducting state, the switch (S Li S L2 S L1 S R1 S R2 S Ri Used to be controlled, enabling the following to switch to start. The two switches (S) are included, which are electrically connected to the two terminals (T1, T2) of the switching device (1). Li S Ri The switch pair, or Including the two switches (S) electrically connected to the center node (Nc) of the first series connection (SC1). L1 S R1 The switch pair mentioned above.

16. A method for switching the switching device (1) according to any one of the preceding claims between an on state and an off state, wherein, The method includes the following steps: The switch (S) of the control device (1) Li S L2 S L1 S R1 S R2 S Ri ), so that the switch (S) Li S L2 S L1 S R1 S R2 S Ri At least two switches of the device will not switch between the on state and the off state simultaneously.

17. The method of claim 16, comprising the following steps: The switch (S) of the control device (1) Li S L2 ,S L1 S R1 S R2 S Ri ), so that the switch (S) Li S L2 S L1 S R1 S R2 S Ri According to the order in the first series connection (SC1), the system switches between the on state and the off state in sequence.

18. The method of claim 16 or 17, comprising the following steps: The switch (S) of the control device (1) Li S L2 S L1 S R1 S R2 S Ri This causes one of the switches electrically connected to one of the two terminals (T1, T2) to switch between the on state and the off state first.

19. The method according to claim 16 or 17, wherein, In the case where the first series connection of the switching device comprises an even number of switches of four or more, two switches equidistant from the center node (Nc) of the first series connection (SC1) in terms of nodes are switch pairs, such that the first series connection (SC1) comprises multiple switch pairs; the method includes the following steps: The switch (S) of the control device (1) Li S L2 ,S L1 S R1 S R2 S Ri ), so that: At least one switch pair of the plurality of switch pairs simultaneously switches between the on state and the off state, and The two switches of each of the other switch pairs of the plurality of switch pairs are switched sequentially.

20. The method according to claim 16 or 17, wherein, In the case where the first series connection of the switching device comprises an even number of switches of four or more, two switches equidistant from the center node (Nc) of the first series connection (SC1) in terms of nodes are switch pairs, such that the first series connection (SC1) comprises multiple switch pairs; the method includes the following steps: The switch (S) of the control device (1) Li S L2 S L1 S R1 S R2 S Ri ), so that: The two switches of each of the plurality of switch pairs switch simultaneously between the on state and the off state, wherein at least two of the plurality of switch pairs do not switch simultaneously between the on state and the off state.

21. The method according to claim 16 or 17, wherein, In the case where the first series connection of the switching device comprises an even number of switches of four or more, two switches equidistant from the center node (Nc) of the first series connection (SC1) in terms of nodes are switch pairs, such that the first series connection (SC1) comprises multiple switch pairs; the method includes the following steps: The switch (S) of the control device (1) Li S L2 S L1 S R1 S R2 S Ri ), so that: Includes two switches (S) electrically connected to the two terminals (T1, T2) of the switching device (1). Li S Ri The switch pair or includes two switches (S) electrically connected to the center node (Nc) of the first series connection (SC1). L1 S R1 The switch pair first switches from the conducting state to the non-conducting state, and the other switch pairs of the plurality of switch pairs sequentially switch from the conducting state to the non-conducting state according to the order of the other switch pairs in the first series connection (SC1), so as to switch the switching device (1) from the conducting state to the non-conducting state; and The two switches (S) are included, which are electrically connected to the two terminals (T1, T2) of the switching device (1). Li S Ri The switch pair or includes the two switches (S) electrically connected to the center node (Nc) of the first series connection (SC1). L1 S R1 The switch pair of the plurality of switches first switches from the non-conducting state to the conducting state, and the other switch pairs of the plurality of switch pairs switch from the non-conducting state to the conducting state in sequence according to the order of the other switch pairs in the first series connection (SC1), so as to switch the switching device (1) from the non-conducting state to the conducting state.

22. The method according to claim 16 or 17, wherein, In the case where the first series connection of the switching device comprises an even number of switches of four or more, two switches equidistant from the center node (Nc) of the first series connection (SC1) in terms of nodes are switch pairs, such that the first series connection (SC1) comprises multiple switch pairs; the method includes the following steps: The switch (S) of the control device (1) Li S L2 S L1 S R1 S R2 S Ri This allows you to switch to the start using the following method. The two switches (S) are included, which are electrically connected to the two terminals (T1, T2) of the switching device (1). Li S Ri The switch pair, or Including the two switches (S) electrically connected to the center node (Nc) of the first series connection (SC1). L1 S R1 The switch pair, Used to switch the switching device (1) from the on state to the off state and from the off state to the on state.

23. A converter system (2) having At least one converter (3) includes at least one switching device (1) according to any one of claims 1 to 15 for controlling the power conversion of the at least one converter (3).

24. The converter system (2) according to claim 23, comprising: Control unit (4) for controlling the power conversion of the at least one converter (3) by performing the method according to any one of claims 16 to 22, for switching at least one switching device (1) of the at least one converter (3) between an on state and an off state.

Images