Multi-level hybrid clamping converter and control method

Abstract

The invention provides a multi-level hybrid clamping type converter and a control method, the multi-level hybrid clamping type converter comprises a direct current input source, a first direct current bus capacitor, a second direct current bus capacitor and a three-phase circuit, the positive electrode of the direct current input source is electrically connected with the positive electrode of the first direct current bus capacitor, and the negative electrode of the second direct current bus capacitor is electrically connected with the three-phase circuit; the cathode of the DC input source is electrically connected with the cathode of the second DC bus capacitor. The cathode of the first direct current bus capacitor is grounded; the anode of the second DC bus capacitor is grounded; the first end of the three-phase circuit is electrically connected with the anode of the first direct-current bus capacitor, and the second end of the three-phase circuit is electrically connected with the cathode of the second direct-current bus capacitor; each phase circuit in the three-phase circuit comprises a first switch module, a second switch module, a third switch module and flying capacitors, and the flying capacitors comprise a first flying capacitor, a second flying capacitor and a third flying capacitor. The stability of the converter is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of converters, and in particular to a multi-level hybrid clamped converter and a control method thereof. Background Art

[0002] In the fields of new energy grid connection and medium-voltage high-power fast charging applications, traditional multi-level converter topologies often face the following problems due to uneven voltage distribution, fixed bridge arm paths, and a single voltage-dividing mechanism: Uneven device voltage stress distribution: Different switching tubes experience significant differences in voltage. Some components may experience voltages close to the DC bus voltage for extended periods, while others may only experience near-zero voltage. This necessitates the use of components with higher voltage ratings to accommodate the highest stress paths when designing circuits, resulting in more expensive devices. Furthermore, uneven voltage stress distribution increases heat loss and damage risk in high-voltage components, reducing the overall reliability and stability of the system. Summary of the Invention

[0003] The present invention aims to provide a multi-level hybrid clamped converter and a control method thereof, so as to solve the above technical problems and improve the stability of the converter.

[0004] In order to solve the above technical problems, the present invention provides a multi-level hybrid clamped converter, comprising: a DC input source, a first DC bus capacitor, a second DC bus capacitor, and a three-phase circuit, wherein:

[0005] The positive electrode of the DC input source is electrically connected to the anode of the first DC bus capacitor, and the negative electrode of the DC input source is electrically connected to the cathode of the second DC bus capacitor;

[0006] The cathode of the first DC bus capacitor is grounded;

[0007] The anode of the second DC bus capacitor is grounded;

[0008] A first end of the three-phase circuit is electrically connected to the anode of the first DC bus capacitor, and a second end of the three-phase circuit is electrically connected to the cathode of the second DC bus capacitor;

[0009] Each phase circuit in the three-phase circuit includes: a first switch module, a second switch module, a third switch module and a flying capacitor, wherein the flying capacitor includes a first flying capacitor, a second flying capacitor and a third flying capacitor, wherein:

[0010] A first end of the first switch module is electrically connected to the anode of the first DC bus capacitor, a second end of the first switch module is electrically connected to the cathode of the second DC bus capacitor, a third end of the first switch module is electrically connected to the anode of the first flying capacitor, a fourth end of the first switch module is electrically connected to the cathode of the second flying capacitor, a fifth end of the first switch module is grounded, and a sixth end of the first switch module is electrically connected to the cathode of the first flying capacitor;

[0011] A cathode of the first flying capacitor is electrically connected to an anode of the second flying capacitor;

[0012] a first end of the second switch module electrically connected to the anode of the first flying capacitor, a second end of the second switch module electrically connected to the cathode of the second flying capacitor, a third end of the second switch module electrically connected to the anode of the third flying capacitor, a fourth end of the second switch module electrically connected to the cathode of the third flying capacitor, and a fifth end of the second switch module electrically connected to the cathode of the first flying capacitor;

[0013] A first end of the third switch module is electrically connected to an anode of the third flying capacitor, and a second end of the third switch module is electrically connected to a cathode of the third flying capacitor.

[0014] In the above scheme, the positive electrode of the DC input source is electrically connected to the anode of the first DC bus capacitor, and the negative electrode of the DC input source is electrically connected to the cathode of the second DC bus capacitor; the cathode of the first DC bus capacitor is grounded; the anode of the second DC bus capacitor is grounded; the first end of the three-phase circuit is electrically connected to the anode of the first DC bus capacitor, and the second end of the three-phase circuit is electrically connected to the cathode of the second DC bus capacitor, thereby constructing a converter topology; for each phase circuit in the three-phase circuit, it includes: a first switch module, a second switch module, a third switch module and a flying capacitor, and the flying capacitor includes a first flying capacitor, a second flying capacitor and a third flying capacitor, wherein: the first end of the first switch module is electrically connected to the anode of the first DC bus capacitor, the second end of the first switch module is electrically connected to the cathode of the second DC bus capacitor, and the third end of the first switch module is electrically connected to the cathode of the second DC bus capacitor. The first switching module is electrically connected to the anode of the first flying capacitor, the fourth end of the first switching module is electrically connected to the cathode of the second flying capacitor, the fifth end of the first switching module is grounded, and the sixth end of the first switching module is electrically connected to the cathode of the first flying capacitor; the cathode of the first flying capacitor is electrically connected to the anode of the second flying capacitor; the first end of the second switching module is electrically connected to the anode of the first flying capacitor, the second end of the second switching module is electrically connected to the cathode of the second flying capacitor, the third end of the second switching module is electrically connected to the anode of the third flying capacitor, the fourth end of the second switching module is electrically connected to the cathode of the third flying capacitor, and the fifth end of the second switch module is electrically connected to the cathode of the first flying capacitor; the first end of the third switching module is electrically connected to the anode of the third flying capacitor, and the second end of the third switch module is electrically connected to the cathode of the third flying capacitor. By introducing first, second, and third flying capacitors, placed between different switch modules, they provide an intermediate voltage level. By superimposing the voltage across the flying capacitors, each switch module only needs to bear a portion of the voltage. The dynamic charging and discharging of the flying capacitors helps control the voltage across the capacitor terminals, further reducing transient stress. This solves the severe imbalance in voltage stress distribution across the converter components and improves converter stability.

[0015] Furthermore, the first switch module includes a first main switch tube, a sixth main switch tube, a first auxiliary switch tube, and a sixth auxiliary switch tube; the second switch module includes a second main switch tube, a third main switch tube, a fifth main switch tube, a second auxiliary switch tube, a third auxiliary switch tube, and a fifth auxiliary switch tube; the third switch module includes a fourth main switch tube and a fourth auxiliary switch tube, wherein:

[0016] The drain of the first main switch is electrically connected to the anode of the first DC bus capacitor, and the source of the first main switch is electrically connected to the drain of the second main switch;

[0017] The source of the second main switch is electrically connected to the drain of the second auxiliary switch;

[0018] The source of the second auxiliary switch is electrically connected to the drain of the first auxiliary switch;

[0019] The source of the first auxiliary switch is electrically connected to the source of the sixth main switch;

[0020] The drain of the sixth main switch is grounded;

[0021] The source of the sixth auxiliary switch is electrically connected to the cathode of the second DC bus capacitor, and the drain of the sixth auxiliary switch is electrically connected to the source of the fifth auxiliary switch;

[0022] The drain of the fifth auxiliary switch is electrically connected to the source of the fifth main switch;

[0023] The drain of the fifth main switch is electrically connected to the drain of the first auxiliary switch;

[0024] The source of the first auxiliary switch tube is electrically connected to the source of the sixth auxiliary switch tube;

[0025] The drain of the sixth auxiliary switch is grounded;

[0026] An anode of the first flying capacitor is electrically connected to a source of the first main switch tube, and a cathode of the first flying capacitor is electrically connected to an anode of the second flying capacitor;

[0027] An anode of the second flying capacitor is electrically connected to a drain of the sixth auxiliary switch tube;

[0028] The drain of the third main switch is electrically connected to the source of the second main switch, and the source of the third main switch is electrically connected to the drain of the fourth main switch;

[0029] The source of the third auxiliary switch is electrically connected to the drain of the fifth auxiliary switch, and the drain of the third auxiliary switch is electrically connected to the source of the fourth auxiliary switch;

[0030] An anode of the third flying capacitor is electrically connected to the source of the third main switch tube, and a cathode of the third flying capacitor is electrically connected to the drain of the third auxiliary switch tube;

[0031] The source of the fourth main switch tube is electrically connected to the drain of the fourth auxiliary switch tube.

[0032] In the above solution, voltage division is achieved by introducing a flying capacitor.

[0033] The present invention further provides a control method, which is applied to a controller, wherein the controller is electrically connected to the multi-level hybrid clamped converter described above, and the method comprises:

[0034] Obtaining a preset output voltage, a current phase current direction in the multi-level hybrid clamped converter, and a current capacitance state of a flying capacitor;

[0035] Determining a switching state of a switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor;

[0036] generating complementary drive signals based on the switch states;

[0037] The switching state of the switch module in the multi-level hybrid clamped converter is controlled by the driving signal, so that the multi-level hybrid clamped converter outputs a target output voltage equal to the value of the preset output voltage.

[0038] In this solution, flying capacitors are introduced and placed between different switch modules to provide an intermediate voltage level. By superimposing the voltage across the flying capacitors, each switch module only needs to bear a portion of the voltage. The dynamic charging and discharging of the flying capacitors helps control the voltage across the capacitor terminals, further reducing transient stress. This solves the severe imbalance in voltage stress distribution across the converter components and improves converter stability.

[0039] Furthermore, when the preset output voltage is 1 / 2 of the DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0040] For each phase circuit in the multi-level hybrid clamped converter:

[0041] Determine that the switch states of the first main switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on.

[0042] In the above solution, a preset output voltage is achieved which is 1 / 2 of the voltage output of the DC input source.

[0043] Furthermore, when the preset output voltage is a 3 / 8 DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0044] For each phase circuit in the multi-level hybrid clamped converter:

[0045] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first main switch tube, the second main switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0046] When the current phase current flows from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first main switch tube, the second main switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0047] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0048] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, it is determined that the switching states of the first main switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube and the sixth main switch tube are on.

[0049] In the above solution, a preset output voltage of 3 / 8 of the DC input source is achieved.

[0050] Furthermore, when the preset output voltage is 1 / 4 of a DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0051] For each phase circuit in the multi-level hybrid clamped converter:

[0052] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third main switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0053] When the current phase current flows from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third main switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0054] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0055] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth main switch tube and the sixth main switch tube are on.

[0056] In the above scheme, a preset output voltage is achieved as a voltage output of 1 / 4 of the DC input source.

[0057] Furthermore, when the preset output voltage is 1 / 8 of the DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0058] For each phase circuit in the multi-level hybrid clamped converter:

[0059] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0060] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0061] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0062] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0063] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0064] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube and the sixth main switch tube are on.

[0065] In the above solution, a preset output voltage of 1 / 8 of the DC input source voltage is achieved.

[0066] Furthermore, when the preset output voltage is 0, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0067] For each phase circuit in the multi-level hybrid clamped converter:

[0068] Determining that the switch states of the first auxiliary switch tube, the second auxiliary switch tube, the third main switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on, or determining that the switch states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0069] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0070] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0071] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth auxiliary switch tube are on;

[0072] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth auxiliary switch tube and the sixth auxiliary switch tube are on.

[0073] In the above solution, the voltage output of the DC input source with a preset output voltage of 0 is achieved.

[0074] Furthermore, when the preset output voltage is a −1 / 8 DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0075] For each phase circuit in the multi-level hybrid clamped converter:

[0076] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0077] When the current phase current flows from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0078] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0079] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0080] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth auxiliary switch tube are on;

[0081] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube and the sixth auxiliary switch tube are on.

[0082] In the above scheme, a preset output voltage of -1 / 8 of the DC input source is achieved.

[0083] Furthermore, when the preset output voltage is -1 / 4 of a DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0084] For each phase circuit in the multi-level hybrid clamped converter:

[0085] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0086] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0087] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth auxiliary switch tube are on;

[0088] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth main switch tube and the sixth auxiliary switch tube are on.

[0089] In the above solution, a preset output voltage of -1 / 4 of the DC input source is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] Figure 1 A schematic diagram of a multi-level hybrid clamped converter architecture provided by one embodiment of the present invention;

[0091] Figure 2 An equivalent circuit of a multi-level hybrid clamped converter (output 1 / 2U) provided by an embodiment of the present invention dc );

[0092] Figure 3An equivalent circuit of a multi-level hybrid clamped converter (output 3 / 8U) provided by an embodiment of the present invention dc );

[0093] Figure 4 An equivalent circuit of a multi-level hybrid clamped converter (output 3 / 8U) provided by an embodiment of the present invention dc );

[0094] Figure 5 An equivalent circuit of a multi-level hybrid clamped converter (output 1 / 4U) provided by an embodiment of the present invention dc );

[0095] Figure 6 An equivalent circuit of a multi-level hybrid clamped converter (output 1 / 4U) provided by an embodiment of the present invention dc );

[0096] Figure 7 An equivalent circuit of a multi-level hybrid clamped converter (output 1 / 8U) provided by an embodiment of the present invention dc );

[0097] Figure 8 An equivalent circuit of a multi-level hybrid clamped converter (output 1 / 8U) provided by an embodiment of the present invention dc );

[0098] Figure 9 An equivalent circuit of a multi-level hybrid clamped converter (output 1 / 8U) provided by an embodiment of the present invention dc );

[0099] Figure 10 An equivalent circuit of a multi-level hybrid clamped converter (output 0U) provided in one embodiment of the present invention dc );

[0100] Figure 11 An equivalent circuit of a multi-level hybrid clamped converter (output 0U) provided in one embodiment of the present invention dc );

[0101] Figure 12 An equivalent circuit of a multi-level hybrid clamped converter (output 0U) provided in one embodiment of the present invention dc );

[0102] Figure 13 An equivalent circuit of a multi-level hybrid clamped converter (output 0U) provided in one embodiment of the present invention dc );

[0103] Figure 14An equivalent circuit of a multi-level hybrid clamped converter (output -1 / 8U) provided by an embodiment of the present invention dc );

[0104] Figure 15 An equivalent circuit of a multi-level hybrid clamped converter (output -1 / 8U) provided by an embodiment of the present invention dc );

[0105] Figure 16 An equivalent circuit of a multi-level hybrid clamped converter (output -1 / 8U) provided by an embodiment of the present invention dc );

[0106] Figure 17 An equivalent circuit of a multi-level hybrid clamped converter (output -1 / 4U) provided by an embodiment of the present invention dc );

[0107] Figure 18 An equivalent circuit of a multi-level hybrid clamped converter (output -1 / 4U) provided by an embodiment of the present invention dc );

[0108] Figure 19 An equivalent circuit of a multi-level hybrid clamped converter (output -3 / 8U) provided by an embodiment of the present invention dc );

[0109] Figure 20 An equivalent circuit of a multi-level hybrid clamped converter (output -3 / 8U) provided by an embodiment of the present invention dc );

[0110] Figure 21 An equivalent circuit of a multi-level hybrid clamped converter (output -1 / 2U) provided by an embodiment of the present invention dc );

[0111] Figure 22 A schematic diagram of a control method provided by an embodiment of the present invention;

[0112] Figure ID:

[0113] A first switch module 110 , a second switch module 120 , and a third switch module 130 . DETAILED DESCRIPTION

[0114] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0115] See Figure 1 This embodiment provides a multi-level hybrid clamped converter, comprising: a DC input source, a first DC bus capacitor, a second DC bus capacitor, and a three-phase circuit, wherein:

[0116] The positive electrode of the DC input source is electrically connected to the anode of the first DC bus capacitor, and the negative electrode of the DC input source is electrically connected to the cathode of the second DC bus capacitor;

[0117] The cathode of the first DC bus capacitor is grounded;

[0118] The anode of the second DC bus capacitor is grounded;

[0119] A first end of the three-phase circuit is electrically connected to the anode of the first DC bus capacitor, and a second end of the three-phase circuit is electrically connected to the cathode of the second DC bus capacitor;

[0120] Each phase circuit in the three-phase circuit includes: a first switch module 110, a second switch module 120, a third switch module 130 and a flying capacitor, wherein the flying capacitor includes a first flying capacitor, a second flying capacitor and a third flying capacitor, wherein:

[0121] A first end of the first switch module 110 is electrically connected to the anode of the first DC bus capacitor, a second end of the first switch module 110 is electrically connected to the cathode of the second DC bus capacitor, a third end of the first switch module 110 is electrically connected to the anode of the first flying capacitor, a fourth end of the first switch module 110 is electrically connected to the cathode of the second flying capacitor, a fifth end of the first switch module 110 is grounded, and a sixth end of the first switch module 110 is electrically connected to the cathode of the first flying capacitor;

[0122] The cathode of the first flying capacitor is electrically connected to the anode of the second flying capacitor;

[0123] A first end of the second switch module 120 is electrically connected to the anode of the first flying capacitor, a second end of the second switch module 120 is electrically connected to the cathode of the second flying capacitor, a third end of the second switch module 120 is electrically connected to the anode of the third flying capacitor, a fourth end of the second switch module 120 is electrically connected to the cathode of the third flying capacitor, and a fifth end of the second switch module 120 is electrically connected to the cathode of the first flying capacitor;

[0124] A first end of the third switch module 130 is electrically connected to the anode of the third flying capacitor, and a second end of the third switch module 130 is electrically connected to the cathode of the third flying capacitor.

[0125] In the above scheme, the positive electrode of the DC input source is electrically connected to the anode of the first DC bus capacitor, and the negative electrode of the DC input source is electrically connected to the cathode of the second DC bus capacitor; the cathode of the first DC bus capacitor is grounded; the anode of the second DC bus capacitor is grounded; the first end of the three-phase circuit is electrically connected to the anode of the first DC bus capacitor, and the second end of the three-phase circuit is electrically connected to the cathode of the second DC bus capacitor, thereby constructing a converter topology; for each phase circuit in the three-phase circuit, it includes: a first switch module 110, a second switch module 120, a third switch module 130 and a flying capacitor, and the flying capacitor includes a first flying capacitor, a second flying capacitor and a third flying capacitor, wherein: the first end of the first switch module 110 is electrically connected to the anode of the first DC bus capacitor, the second end of the first switch module 110 is electrically connected to the cathode of the second DC bus capacitor, and the third end of the first switch module 110 is electrically connected to the cathode of the second DC bus capacitor. The anode of the first flying capacitor is electrically connected, the fourth end of the first switch module 110 is electrically connected to the cathode of the second flying capacitor, the fifth end of the first switch module 110 is grounded, and the sixth end of the first switch module 110 is electrically connected to the cathode of the first flying capacitor; the cathode of the first flying capacitor is electrically connected to the anode of the second flying capacitor; the first end of the second switch module 120 is electrically connected to the anode of the first flying capacitor, the second end of the second switch module 120 is electrically connected to the cathode of the second flying capacitor, the third end of the second switch module 120 is electrically connected to the anode of the third flying capacitor, the fourth end of the second switch module 120 is electrically connected to the cathode of the third flying capacitor, and the fifth end of the second switch module 120 is electrically connected to the cathode of the first flying capacitor; the first end of the third switch module 130 is electrically connected to the anode of the third flying capacitor, and the second end of the third switch module 130 is electrically connected to the cathode of the third flying capacitor. By introducing first, second, and third flying capacitors, placed between different switch modules, they provide an intermediate voltage level. By superimposing the voltage across the flying capacitors, each switch module only needs to bear a portion of the voltage. The dynamic charging and discharging of the flying capacitors helps control the voltage across the capacitor terminals, further reducing transient stress. This solves the severe imbalance in voltage stress distribution across the converter components and improves converter stability.

[0126] Furthermore, the multi-level hybrid clamped converter is composed of a DC input source (U dc ), DC bus capacitor (first DC bus capacitor C dc1 , the second DC bus capacitor C dc2 ) and three-phase circuit. Among them, Figure 1 The specific components of the DC bus capacitor and one of the three-phase circuits are provided.

[0127] In another embodiment, the first switch module 110 includes a first main switch tube, a sixth main switch tube, a first auxiliary switch tube, and a sixth auxiliary switch tube; the second switch module 120 includes a second main switch tube, a third main switch tube, a fifth main switch tube, a second auxiliary switch tube, a third auxiliary switch tube, and a fifth auxiliary switch tube; and the third switch module 130 includes a fourth main switch tube and a fourth auxiliary switch tube, wherein:

[0128] The drain of the first main switch tube is electrically connected to the anode of the first DC bus capacitor, and the source of the first main switch tube is electrically connected to the drain of the second main switch tube;

[0129] The source of the second main switch tube is electrically connected to the drain of the second auxiliary switch tube;

[0130] The source of the second auxiliary switch tube is electrically connected to the drain of the first auxiliary switch tube;

[0131] The source of the first auxiliary switch is electrically connected to the source of the sixth main switch;

[0132] The drain of the sixth main switch tube is grounded;

[0133] The source of the sixth auxiliary switch tube is electrically connected to the cathode of the second DC bus capacitor, and the drain of the sixth auxiliary switch tube is electrically connected to the source of the fifth auxiliary switch tube;

[0134] The drain of the fifth auxiliary switch tube is electrically connected to the source of the fifth main switch tube;

[0135] The drain of the fifth main switch tube is electrically connected to the drain of the first auxiliary switch tube;

[0136] The source of the first auxiliary switch tube is electrically connected to the source of the sixth auxiliary switch tube;

[0137] The drain of the sixth auxiliary switch tube is grounded;

[0138] The anode of the first flying capacitor is electrically connected to the source of the first main switch tube, and the cathode of the first flying capacitor is electrically connected to the anode of the second flying capacitor;

[0139] An anode of the second flying capacitor is electrically connected to a drain of the sixth auxiliary switch tube;

[0140] The drain of the third main switch tube is electrically connected to the source of the second main switch tube, and the source of the third main switch tube is electrically connected to the drain of the fourth main switch tube;

[0141] The source of the third auxiliary switch tube is electrically connected to the drain of the fifth auxiliary switch tube, and the drain of the third auxiliary switch tube is electrically connected to the source of the fourth auxiliary switch tube;

[0142] An anode of the third flying capacitor is electrically connected to the source of the third main switch tube, and a cathode of the third flying capacitor is electrically connected to the drain of the third auxiliary switch tube;

[0143] The source of the fourth main switch tube is electrically connected to the drain of the fourth auxiliary switch tube.

[0144] It should be noted that the x-phase circuit (x refers to phase A, phase B, or phase C in the three-phase circuit) of the multi-level hybrid clamped converter topology is composed of the first main switch tube S x1 , the second main switch tube S x2 , the third main switch tube S x3 , the fourth main switch tube S x4 , the fifth main switch tube S x5 , the sixth main switch tube S x6 , the first auxiliary switch tube S x1′ , the second auxiliary switch tube S x2′ , the third auxiliary switch tube S x3′ , the fourth auxiliary switch tube S x4′ , the fifth auxiliary switch tube S x5′ , the sixth auxiliary switch tube S x6′ 、The first flying capacitor C fx1 , the second flying capacitor C fx2 、The third flying capacitor C fx3 The first switch module 110 includes S x1 、S x6 、S x1′ and S x6′ The second switch module 120 includes S x2 、S x3 、S x5 、S x2′ 、S x3′ and S x5′ The third switch module 130 includes: x4 and S x4′ . S x1 The drain is connected to C dc1 Anode, S x1 The source is connected to S x2 The drain and C fx1 Anode, S x2 The source is connected to S x2′ The drain and S x3 The drain, S x3 The source is connected to S x4 The drain and C fx3 Anode, S x2′ The source is connected to S x1′ The drain, S x5 The drain, C fx1 and C fx2 , Sx1′ The source is connected to S x6 The source, S x1′ The drain is connected to C dc1 The cathode and C dc2 Anode, S x6′ The source is connected to C dc2 cathode, S x6′ The drain is connected to the source and C fx2 cathode, S x5′ The drain is connected to S x5 The source and S x3′ The source, S x3′ The drain is connected to S x4′ The source and C fx3 cathode, S x4′ The drain is connected to S x4 The source of the x-phase.

[0145] See Figure 22 This embodiment provides a control method, which is applied to a controller, wherein the controller is electrically connected to a multi-level hybrid clamped converter, and the method includes:

[0146] Step S1: obtaining a preset output voltage, a current phase current direction in the multi-level hybrid clamped converter, and a current capacitance state of the flying capacitor;

[0147] Step S2: determining a switching state of a switch module in the multi-level hybrid clamped converter based on a preset output voltage, a current phase current direction, and a current capacitance state of the flying capacitor;

[0148] Step S3: generating a complementary driving signal based on the switch state;

[0149] Step S4: controlling the switching state of the switch module in the multi-level hybrid clamped converter by the driving signal, so that the multi-level hybrid clamped converter outputs a target output voltage equal to the preset output voltage.

[0150] It should be noted that the preset output voltage is obtained, which is the voltage required by the customer, as well as the current phase current direction and the current capacitance state of the flying capacitor in the current multi-level hybrid clamped converter. It is understood that the flying capacitor includes a first flying capacitor, a second flying capacitor, and a third flying capacitor. Based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor, the switching state of the switch module in the multi-level hybrid clamped converter is determined. It is understood that the switch module includes a first switch module 110, a second switch module 120, and a third switch module 130. The switching state of the switch module refers to the switching state of each main switch and auxiliary switch in the first switch module 110, the second switch module 120, and the third switch module 130, wherein the main switch includes a first main switch, a second main switch, a third main switch, a fourth main switch, a fifth main switch, and a sixth main switch, and the auxiliary switch includes a first auxiliary switch, a second auxiliary switch, a third auxiliary switch, a fourth auxiliary switch, a fifth auxiliary switch, and a sixth auxiliary switch. The switching state of the switch module in the multi-level hybrid clamped converter is controlled by the driving signal, specifically, the conduction or shutdown of each main switch tube and auxiliary switch tube in the multi-level hybrid clamped converter is controlled by the driving signal; the multi-level hybrid clamped converter outputs a target output voltage equal to the value of the preset output voltage, S x4‘ The drain is connected to S x4 The source of the x-phase is used as the output terminal of the x-phase to output the final target output voltage.

[0151] Furthermore, in the x-phase circuit of the multi-level hybrid clamped converter, S x1′ The driving signal and S x1 The driving signal of S x2′ The driving signal and S x2 The driving signal of S x3′ The driving signal and S x3 The driving signal of S x4′ The driving signal and S x4 The driving signal of S x5′ The driving signal and S x5 The driving signal of S x6′ The driving signal and S x6 The driving signals of the first DC bus capacitor C are complementary. Based on the circuit structure design of the multi-level hybrid clamped converter, the driving signals of the main switch tube and the auxiliary switch tube must be complementary. dc1 , the second DC bus capacitor C dc2 、S x1 、S x6′ The voltage stress is 1 / 2 of the input voltage, S x1′ 、S x6 、Sx2 、S x2′ 、S x5 、S x5′ 、C fx1 、C fx2 The voltage stress is 1 / 4 of the input voltage, S x3 、S x3′ 、S x4 、S x4′ 、C fx3 The voltage stress is 1 / 8 of the input voltage. It can be understood that the complementary driving signals mean that when one of the complementary signals is turned on, the corresponding signal must be turned off. For example, if the controller generates a conduction signal S x1 The controller controls S x1 turns on, and at the same time generates a turn-off S x1′ The driving signal controls S x1′ Shut down.

[0152] In another embodiment, when the preset output voltage is half of the DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0153] For each phase circuit in the multilevel hybrid clamped converter:

[0154] Determine that the switch states of the first main switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on.

[0155] It should be noted that, taking the x (x = A, B, C) phase circuit as an example, the main switch tube S x1 、S x2 、S x3 、S x4 、S x5 、S x6 20 switching states can be formed, as shown in Table 1. The influence of each switching state on the charge and discharge state of each flying capacitor is shown in Table 1.

[0156] Table 1 The influence of each switch state on the charging and discharging of the flying capacitor

[0157]

[0158] The equivalent circuit description of the x (x = a, b, c) phase circuit is as follows: Figure 2 As shown, when the preset output voltage is 1 / 2U dc When the switch state combination of A1 is used: x1 、S x2 、S x3 , the fourth main switch tube Sx4 、S x5 、S x6 Send the conduction drive signal. Correspondingly, give S x1′ 、S x2′ 、S x3′ 、S x4′ 、S x5′ 、S x6′ Send a shutdown drive signal, when the current i x outflow, current flows through S x1 、S x2 、S x3 、S x4 , the target output voltage u is equal to the preset output voltage x When the current i x Inflow, current flows through S x4 、S x3 、S x2 、S x1 Regardless of the current i x outflow(i x ≥0, that is, the current direction of the phase current is the multi-level hybrid clamped converter flowing to the output end) or flowing into (i x <0, that is, the current phase current flows from the output end to the multi-level hybrid clamped converter), C fx1 、C fx2 、C fx3 None of them are affected.

[0159] Furthermore, it can be understood that in order to achieve dynamic voltage equalization of the flying capacitors, it is necessary to determine the switch tube state combination in combination with the current capacitance state of each flying capacitor. For example, when the capacitance voltage of the flying capacitor is lower than the preset threshold, it is recommended to select a switch tube state combination that can charge the flying capacitor. When the capacitance voltage of the flying capacitor is higher than the preset threshold, it is recommended to select a switch tube state combination that can discharge the flying capacitor.

[0160] Therefore, in another embodiment, when the preset output voltage is a 3 / 8 DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0161] For each phase circuit in the multilevel hybrid clamped converter:

[0162] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first main switch tube, the second main switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0163] When the current phase current flows from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first main switch tube, the second main switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0164] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than the preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0165] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than the preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than the preset threshold, it is determined that the switching states of the first main switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube and the sixth main switch tube are on.

[0166] It should be noted that if Figure 3 :When the preset output voltage is 3 / 8U dc When B1 is switched on and off, the switch state combination can be used: x1 、S x2 、S x3 、S x4′ 、S x5 、S x6 Send the conduction drive signal. Correspondingly, give S x1′ 、S x2′ 、S x3′ 、S x4 、S x5′ 、S x6′ Send a shutdown drive signal, when the current i x outflow, current flows through S x1 、S x2 、S x3 、C fx3 、S x4′ , the target output voltage u is equal to the preset output voltage x , at this time C fx3 Charging, while C fx1 、C fx2 Not affected; when the current i x Inflow, current flows through S x4′ 、C fx3 、S x3 、S x2 、Sx1 , at this time C fx3 Charging, while C fx1 、C fx2 Therefore, when the preset output voltage is 3 / 8U dc , when the current direction of the current phase is outflow and the current capacitance state of the first flying capacitor is that the capacitor voltage is lower than the preset threshold, give S x1 、S x2 、S x3 、S x4′ 、S x5 、S x6 Send the driving signal to charge the first flying capacitor and output the target output voltage; when the preset output voltage is 3 / 8U dc , when the current direction of the current phase is inflow, the current capacitance state of the flying capacitor is the first flying capacitor. When the capacitance voltage is higher than the preset threshold, give S x1 、S x2 、S x3 、S x4′ 、S x5 、S x6 A conductive driving signal is sent to discharge the first flying capacitor and output a target output voltage.

[0167] In addition, if Figure 4 :When the preset output voltage is 3 / 8U dc When S x1 、S x2′ 、S x3′ 、S x4 、S x5 、S x6 Send the conduction drive signal. Correspondingly, give S x1′ 、S x2 、S x3 、S x4′ 、S x5′ 、S x6′ Send a shutdown drive signal, when the current i x outflow, current flows through S x1 、C fx1 、S x2′ 、S x5 、S x3 、C fx3 、S x4 , the target output voltage u is equal to the preset output voltage x , at this time C fx1 Charging, C fx3 discharge, while C fx2 Not affected; when the current i x Inflow, current flows through S x4、C fx3 、S x3 、S x5 、S x2′ 、C fx1 、S x1 , at this time C fx1 Discharge, C fx3 Charging, while C fx2 Therefore, when the preset output voltage is 3 / 8U dc , when the current direction of the current phase is outflow, the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than the preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than the preset threshold, give S x1 、S x2′ 、S x3′ 、S x4 、S x5 、S x6 Send a driving signal to turn on C fx1 Charging, C fx3 Discharge, and output the target output voltage at the same time; when the preset output voltage is 3 / 8U dc , when the current direction of the current phase is inflow, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than the preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than the preset threshold, give S x1 、S x2′ 、S x3′ 、S x4 、S x5 、S x6 Send a driving signal to turn on C fx1 Discharge, C fx3 charging and outputting the target output voltage at the same time.

[0168] In another embodiment, when the preset output voltage is 1 / 4 of the DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0169] For each phase circuit in the multilevel hybrid clamped converter:

[0170] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third main switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0171] When the current phase current flows from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third main switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0172] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0173] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than the preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth main switch tube and the sixth main switch tube are on.

[0174] It should be noted that if Figure 5 :When the preset output voltage is 1 / 4U dc (DC input source), the switch state combination of C1 can be used: x1 、S x2′ 、S x3 、S x4 、S x5′ 、S x6 Send the conduction drive signal. Correspondingly, give S x1′ 、S x2 、S x3′ 、S x4′ 、S x5 、S x6′ Send a shutdown drive signal, when the current i x outflow, current flows through S x1 、C fx1 、S x2′ 、S x3 、S x4 , the target output voltage u is equal to the preset output voltage x , at this time C fx1 Charging, while C fx2 and C fx3 Not affected; when the current i x Inflow, current flows through S x4 、S x3 、S x2′ 、C fx1 、S x1 , at this time C fx1 discharge, while C fx2 and Cfx3 Not affected.

[0175] Furthermore, if Figure 6 :When the preset output voltage is 1 / 4U dc (DC input source), the switch state combination of C2 can be used: x1′ 、S x2 、S x3 、S x4 、S x5 、S x6 Send the conduction drive signal. Correspondingly, give S x1 、S x2′ 、S x3‘ 、S x4′ 、S x5′ 、S x6′ Send a shutdown drive signal, when the current i x outflow, current flows through S x6 、S x1′ 、C fx1 、S x2 、S x3 、S x4 , the target output voltage u is equal to the preset output voltage x , at this time C fx1 discharge, while C fx2 and C fx3 Not affected; when the current i x Inflow, current flows through S x4 、S x3 、S x2 、C fx1 、S x1′ 、S x6 , at this time C fx1 Charging, while C fx2 and C fx3 Not affected.

[0176] In another embodiment, when the preset output voltage is 1 / 8 of the DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0177] For each phase circuit in the multilevel hybrid clamped converter:

[0178] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than the preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0179] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than the preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0180] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than the preset threshold, determining that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0181] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than the preset threshold, determining that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0182] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0183] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than the preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube and the sixth main switch tube are on.

[0184] It should be noted that if Figure 7 :For each phase circuit: When the preset output voltage is 1 / 8U dc (DC input source), the switch state combination of D1 can be used: x1、S x2′ 、S x3 、S x4′ 、S x5 、S x6 Send the conduction drive signal. Correspondingly, give S x1′ 、S x2 、S x3′ 、S x4 、S x5′ 、S x6′ Send a shutdown drive signal, when the current i x outflow, current flows through S x1 、C fx1 、S x2′ 、S x3 、C fx3 、S x4′ Get the target output voltage u which is equal to the preset output voltage x , at this time C fx1 and C fx3 Charging, C fx2 Not affected; when the current i x Inflow, current flows through S x4′ 、C fx3 、S x3 、S x2′ 、C fx1 、S x1 , at this time C fx1 and C fx3 Discharge, C fx2 Not affected.

[0185] It should be noted that if Figure 8 :For each phase circuit: When the preset output voltage is 1 / 8U dc (DC input source), you can also use the switch state combination of D2: give S x1′ 、S x2 、S x3 、S x4′ 、S x5 、S x6 Send the conduction drive signal. Correspondingly, give S x1′ 、S x2′ 、S x3′ 、S x4 、S x5′ 、S x6′ Send a shutdown drive signal, when the current i x outflow, current flows through S x6 、S x1 、C fx1 、S x2 、S x3 、C fx3 、S x4′, the target output voltage u is equal to the preset output voltage x , at this time C fx1 Discharge, C fx3 Charging, C fx2 Not affected, when the current i x Inflow, current flows through S x4′ 、C fx3 、S x3 、S x2 、C fx1 、S x1 、S x6 , at this time C fx1 Charging, C fx3 Discharge, C fx2 Not affected.

[0186] It should be noted that if Figure 9 :For each phase circuit: When the preset output voltage is 1 / 8U dc (DC input source), you can also use the switch state combination of D3: give S x1′ 、S x2′ 、S x3′ 、S x4′ 、S x5 、S x6 Send the conduction drive signal. Correspondingly, give S x1 、S x2 、S x3 、S x4 、S x5′ 、S x6′ Send a shutdown drive signal, when the current i x outflow, current flows through S x6 、S x1′ 、S x5 、S x3′ 、C fx3 、S x4 , C fx3 Discharge, C fx1 、C fx3 Not affected; when the current i x Inflow, current flows through S x4 、C fx3 、S x3′ 、S x5 、S x1′ 、S x6 、C fx3 Charging, C fx1 、C fx3 Not affected.

[0187] In another embodiment, when the preset output voltage is 0, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0188] For each phase circuit in the multilevel hybrid clamped converter:

[0189] Determining that the switch states of the first auxiliary switch tube, the second auxiliary switch tube, the third main switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on, or determining that the switch states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0190] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than the preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0191] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than the preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0192] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than the preset threshold, determining that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth auxiliary switch tube are on;

[0193] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than the preset threshold, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than the preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth auxiliary switch tube and the sixth auxiliary switch tube are on.

[0194] It should be noted that for each phase circuit in the multi-level hybrid clamped converter: Figure 10 As shown, S x1 '、Sx2 '、S x3 、S x4 、S x5 and S x6 conduction, output voltage u x The magnitude is 0. Regardless of the current i x outflow(i x ≥0) or inflow (i x <0), C fx1 、C fx2 and C fx3 None of them are affected.

[0195] It should be noted that if Figure 11 As shown, S x1 '、S x2 '、S x3 '、S x4 '、S x5 and S x6 conduction, output voltage u x The magnitude is 0. Regardless of the current i x Outflow (ix≥0) or inflow (i x <0), C fx1 、C fx2 and C fx3 None of them are affected.

[0196] It should be noted that if Figure 12 As shown, S x1 、S x2 '、S x3 '、S x4 '、S x5 ' and S x6 conduction, output voltage u x The magnitude is 0. When the current i x outflow(i x ≥0), C fx1 and C fx2 Charging, while C fx3 Not affected; when the current i x Inflow (i x <0), C fx1 and C fx2 discharge, while C fx3 Not affected.

[0197] It should be noted that if Figure 13 As shown, S x1 '、S x2 、S x3 、S x4 、S x5 ' and S x6 'Conduction, output voltage u xThe magnitude is 0. When the current i x outflow(i x ≥0), C fx1 and C fx2 discharge, while C fx3 Not affected; when the current i x Inflow (i x <0), C fx1 and C fx2 Charging, while C fx3 Not affected.

[0198] In another embodiment, when the preset output voltage is a −1 / 8 DC input source, determining the switching state of a switch module in a multi-level hybrid clamped converter based on the preset output voltage, a current phase current direction, and a current capacitance state of a flying capacitor includes:

[0199] For each phase circuit in the multilevel hybrid clamped converter:

[0200] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0201] When the current phase current flows from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on;

[0202] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than the preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0203] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than the preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0204] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than the preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth auxiliary switch tube are on;

[0205] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than the preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than the preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube and the sixth auxiliary switch tube are on.

[0206] It should be noted that if Figure 14 As shown, S x1 '、S x2 '、S x3 、S x4 '、S x5 and S x6 conduction, output voltage u x The size is -1 / 8U dc When the current i x outflow(i x ≥0), C fx3 Charging, while C fx1 and C fx2 Not affected; when the current i x Inflow (i x <0), C fx3 discharge, while C fx1 and C fx2 Not affected.

[0207] like Figure 15 As shown, S x1 '、S x2 '、S x3 '、S x4 、S x5 ' and S x6 conduction, output voltage u x The size is -1 / 8U dc When the current i x outflow(i x ≥0), C fx2 Charging, C fx3 discharge, while C fx1 Not affected; when the current i x When inflow (ix<0), C fx2 Discharge, C fx3 Charging, while Cfx1 Not affected.

[0208] like Figure 16 As shown, S x1 '、S x2 '、S x3 '、S x4 、S x5 and S x6 'Conduction, output voltage u x The size is -1 / 8U dc When the current i x outflow(i x ≥0), C fx2 and C fx3 discharge, while C fx1 Not affected; when the current i x Inflow (i x <0), C fx2 and C fx3 Charging, while C fx1 Not affected.

[0209] In another embodiment, when the preset output voltage is -1 / 4 of the DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes:

[0210] For each phase circuit in the multilevel hybrid clamped converter:

[0211] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0212] When the current phase current flows from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on;

[0213] When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth auxiliary switch tube are on;

[0214] When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than the preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth main switch tube and the sixth auxiliary switch tube are on.

[0215] It should be noted that if Figure 17 As shown, S x1 '、S x2 '、S x3 '、S x4 '、S x5 ' and S x6 conduction, output voltage u x The size is -1 / 4U dc When the current i x outflow(i x ≥0), C fx2 Charging, while C fx1 and C fx3 Not affected; when the current i x Inflow (i x <0), C fx2 discharge, while C fx1 and C fx3 Not affected. Figure 18 As shown, S x1 '、S x2 '、S x3 '、S x4 '、S x5 and S x6 'Conduction, output voltage u x The size is -1 / 4U dc When the current i x outflow(i x ≥0), C fx2 discharge, while C fx1 and C fx3 Not affected; when the current i x Inflow (i x <0), C fx2 Charging, while C fx1 and C fx3 Not affected.

[0216] Furthermore, if Figure 19 As shown, S x1 '、S x2 '、S x3 、S x4 '、S x5 ' and S x6 'Conduction, output voltage u x The size is -3 / 8Udc When the current i x outflow(i x ≥0), C fx2 Discharge, C fx3 Charging, while C fx1 Not affected; when the current i x Inflow (i x <0), C fx2 Charging, C fx3 discharge, while C fx1 Not affected. Figure 20 As shown, S x1 '、S x2 '、S x3 '、S x4 、S x5 ' and S x6 'Conduction, output voltage u x The size is -3 / 8U dc When the current i x outflow(i x ≥0), C fx3 discharge, while C fx1 and C fx2 Not affected; when the current i x Inflow (i x <0), C fx3 Charging, while C fx1 and C fx2 Not affected.

[0217] like Figure 21 As shown, S x1 '、S x2 '、S x3 '、S x4 '、S x5 ' and S x6 'Conduction, output voltage u x The size is -1 / 2U dc Regardless of the current i x outflow(i x ≥0) or inflow (i x <0), C fx1 、C fx2 and C fx3 None of them are affected.

[0218] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A multi-level hybrid clamped converter, characterized in that: include: A DC input source, a first DC bus capacitor, a second DC bus capacitor, and a three-phase circuit, wherein: The positive electrode of the DC input source is electrically connected to the anode of the first DC bus capacitor, and the negative electrode of the DC input source is electrically connected to the cathode of the second DC bus capacitor; The cathode of the first DC bus capacitor is grounded; The anode of the second DC bus capacitor is grounded; A first end of the three-phase circuit is electrically connected to the anode of the first DC bus capacitor, and a second end of the three-phase circuit is electrically connected to the cathode of the second DC bus capacitor; Each phase circuit in the three-phase circuit includes: a first switch module, a second switch module, a third switch module and a flying capacitor, wherein the flying capacitor includes a first flying capacitor, a second flying capacitor and a third flying capacitor, wherein: A first end of the first switch module is electrically connected to the anode of the first DC bus capacitor, a second end of the first switch module is electrically connected to the cathode of the second DC bus capacitor, a third end of the first switch module is electrically connected to the anode of the first flying capacitor, a fourth end of the first switch module is electrically connected to the cathode of the second flying capacitor, a fifth end of the first switch module is grounded, and a sixth end of the first switch module is electrically connected to the cathode of the first flying capacitor; A cathode of the first flying capacitor is electrically connected to an anode of the second flying capacitor; a first end of the second switch module electrically connected to the anode of the first flying capacitor, a second end of the second switch module electrically connected to the cathode of the second flying capacitor, a third end of the second switch module electrically connected to the anode of the third flying capacitor, a fourth end of the second switch module electrically connected to the cathode of the third flying capacitor, and a fifth end of the second switch module electrically connected to the cathode of the first flying capacitor; A first end of the third switch module is electrically connected to an anode of the third flying capacitor, and a second end of the third switch module is electrically connected to a cathode of the third flying capacitor.

2. The multi-level hybrid clamped converter according to claim 1, characterized in that: The first switch module includes a first main switch tube, a sixth main switch tube, a first auxiliary switch tube, and a sixth auxiliary switch tube; the second switch module includes a second main switch tube, a third main switch tube, a fifth main switch tube, a second auxiliary switch tube, a third auxiliary switch tube, and a fifth auxiliary switch tube; the third switch module includes a fourth main switch tube and a fourth auxiliary switch tube, wherein: The drain of the first main switch is electrically connected to the anode of the first DC bus capacitor, and the source of the first main switch is electrically connected to the drain of the second main switch; The source of the second main switch is electrically connected to the drain of the second auxiliary switch; The source of the second auxiliary switch is electrically connected to the drain of the first auxiliary switch; The source of the first auxiliary switch is electrically connected to the source of the sixth main switch; The drain of the sixth main switch is grounded; The source of the sixth auxiliary switch is electrically connected to the cathode of the second DC bus capacitor, and the drain of the sixth auxiliary switch is electrically connected to the source of the fifth auxiliary switch; The drain of the fifth auxiliary switch is electrically connected to the source of the fifth main switch; The drain of the fifth main switch is electrically connected to the drain of the first auxiliary switch; The source of the first auxiliary switch tube is electrically connected to the source of the sixth auxiliary switch tube; The drain of the sixth auxiliary switch is grounded; An anode of the first flying capacitor is electrically connected to a source of the first main switch tube, and a cathode of the first flying capacitor is electrically connected to an anode of the second flying capacitor; An anode of the second flying capacitor is electrically connected to a drain of the sixth auxiliary switch tube; The drain of the third main switch is electrically connected to the source of the second main switch, and the source of the third main switch is electrically connected to the drain of the fourth main switch; The source of the third auxiliary switch is electrically connected to the drain of the fifth auxiliary switch, and the drain of the third auxiliary switch is electrically connected to the source of the fourth auxiliary switch; An anode of the third flying capacitor is electrically connected to the source of the third main switch tube, and a cathode of the third flying capacitor is electrically connected to the drain of the third auxiliary switch tube; The source of the fourth main switch tube is electrically connected to the drain of the fourth auxiliary switch tube.

3. A control method, characterized in that: Applied to a controller, the controller being electrically connected to a multi-level hybrid clamped converter according to any one of claims 1-2, the method comprising: Obtaining a preset output voltage, a current phase current direction in the multi-level hybrid clamped converter, and a current capacitance state of a flying capacitor; Determining a switching state of a switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor; generating complementary drive signals based on the switch states; The switching state of the switch module in the multi-level hybrid clamped converter is controlled by the driving signal, so that the multi-level hybrid clamped converter outputs a target output voltage equal to the value of the preset output voltage.

4. A control method according to claim 3, characterized in that: When the preset output voltage is 1 / 2 of the DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes: For each phase circuit in the multi-level hybrid clamped converter: Determine that the switch states of the first main switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on.

5. A control method according to claim 3, characterized in that: When the preset output voltage is a 3 / 8 DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes: For each phase circuit in the multi-level hybrid clamped converter: When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first main switch tube, the second main switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on; When the current phase current flows from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first main switch tube, the second main switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on; When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on; When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, it is determined that the switching states of the first main switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube and the sixth main switch tube are on.

6. A control method according to claim 3, characterized in that: When the preset output voltage is 1 / 4 of the DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes: For each phase circuit in the multi-level hybrid clamped converter: When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third main switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on; When the current phase current flows from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third main switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on; When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on; When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth main switch tube and the sixth main switch tube are on.

7. A control method according to claim 3, characterized in that: When the preset output voltage is 1 / 8 of the DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes: For each phase circuit in the multi-level hybrid clamped converter: When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on; When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on; When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on; When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on; When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on; When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube and the sixth main switch tube are on.

8. A control method according to claim 3, characterized in that: When the preset output voltage is 0, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes: For each phase circuit in the multi-level hybrid clamped converter: Determining that the switch states of the first auxiliary switch tube, the second auxiliary switch tube, the third main switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth main switch tube are on, or determining that the switch states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on; When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on; When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first main switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on; When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the first flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth auxiliary switch tube are on; When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the first flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second main switch tube, the third main switch tube, the fourth main switch tube, the fifth auxiliary switch tube and the sixth auxiliary switch tube are on.

9. A control method according to claim 3, characterized in that: When the preset output voltage is a −1 / 8 DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes: For each phase circuit in the multi-level hybrid clamped converter: When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on; When the current phase current flows from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third main switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth main switch tube are on; When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on; When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on; When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube, and the sixth auxiliary switch tube are on; When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, and the current capacitance state of the third flying capacitor is that the capacitance voltage is lower than a preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth main switch tube, the fifth main switch tube and the sixth auxiliary switch tube are on.

10. A control method according to claim 3, characterized in that: When the preset output voltage is a -1 / 4 DC input source, determining the switching state of the switch module in the multi-level hybrid clamped converter based on the preset output voltage, the current phase current direction, and the current capacitance state of the flying capacitor includes: For each phase circuit in the multi-level hybrid clamped converter: When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on; When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth auxiliary switch tube, and the sixth main switch tube are on; When the current phase current direction is that the multi-level hybrid clamped converter flows toward the output end, and the current capacitance state of the second flying capacitor is that the capacitance voltage is higher than a preset threshold, determining that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth main switch tube, and the sixth auxiliary switch tube are on; When the current phase current direction is flowing from the output end to the multi-level hybrid clamped converter, and the current capacitance state of the second flying capacitor is that the capacitance voltage is lower than a preset threshold, it is determined that the switching states of the first auxiliary switch tube, the second auxiliary switch tube, the third auxiliary switch tube, the fourth auxiliary switch tube, the fifth main switch tube and the sixth auxiliary switch tube are on.

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