Three-level ANPC converter and low-loss modulation method and modulation device thereof

Abstract

The invention provides a three-level ANPC converter and a low-loss modulation method and device thereof. The low-loss modulation method of the three-level ANPC converter comprises the following steps: determining the direction of a load current and the size of a modulation wave vref; and switching an output level from a P state or an N state to a first state based on the direction of the load current and the size of the modulation wave vref, the first state being a state in which the second switch, the third switch, the fifth switch and the sixth switch are turned on and the other switches are turned off. All switching loss is concentrated on the SiC inner tube, the system loss can be reduced, and the working efficiency is improved. In addition, the circuit can be suitable for any power factor, and the switching loss is always concentrated on the inner tube no matter how the current direction is. Finally, the situation that two pairs of switches act at the same time does not exist in switch state switching, and practical application is easy.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular, to a three-level ANPC converter and its low-loss modulation method and modulation device. Background Art

[0002] Compared with traditional two-level converters, three-level converters have the advantages of reduced output harmonic content, low withstand voltage level of switching tubes, low dv / dt, and high efficiency, and have obvious application advantages in actual industries. Among them, the diode neutral-point-clamped (NPC) three-level converter is one of the most widely used multilevel topologies. However, the three-level NPC converter has only one zero-level switching state, resulting in extremely unbalanced power loss distribution, restricting the further improvement of the system power density, and also bringing great challenges to the heat dissipation design of the system. To solve the above problems, German scholar T. Bruckner proposed the active neutral-point-clamped (ANPC) three-level inverter topology. By using active switching devices to replace two clamping diodes in the three-level NPC, the zero-level state is increased to multiple, greatly improving the flexibility of the inverter to select the commutation loop, and then by controlling the loss distribution of the inverter switching devices, the power loss balance between the inner and outer tubes is achieved.

[0003] Compared with traditional silicon (Si) devices, wide bandgap power devices such as silicon carbide (SiC) have the advantages of fast switching speed, high temperature resistance, and low switching loss, and have obvious advantages in promoting energy conservation and emission reduction and improving the system power density. However, the cost of current SiC devices is still relatively high. If all the switching tubes in the three-level ANPC are replaced with SiC devices, the manufacturing cost will increase significantly. In order to minimize the manufacturing cost while fully exploiting the advantages of SiC devices in switching frequency and heat dissipation and increasing the system power density, many domestic and foreign scholars have proposed an improved three-level ANPC topology using SiC devices to replace some Si devices on the basis of the three-level ANPC topology. In addition, the prior art also proposed a 2-SiC hybrid three-level ANPC topology structure in which two inner tubes are replaced with SiC devices, and a special modulation strategy is proposed for this topology structure. However, under this modulation method, the losses of the two inner tubes are still much higher than those of the outer tubes and the clamping tubes. Therefore, there is an urgent need for a modulation method to further reduce the losses of the inner tubes and improve the system operating efficiency. Summary of the Invention

[0004] In view of this, the present invention provides a three-level ANPC converter and its low-loss modulation method and modulation device to solve at least one of the above-mentioned problems.

[0005] To achieve the above object, the present invention adopts the following solutions:

[0006] According to a first aspect of the present invention, a low-loss modulation method for a three-level ANPC converter is provided. The three-level ANPC converter includes three-phase bridge arms, and each phase bridge arm includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch. The positive and negative poles of the three-level ANPC converter are point P and point N respectively, the midpoint between point P and point N is point O, a first capacitor is connected in parallel between point P and point O, and a second capacitor is connected in parallel between point O and point N. The first switch, the second switch, the third switch, and the fourth switch are sequentially connected in series between point P and point N. After the fifth switch and the sixth switch are connected in series, they are connected in parallel with the second switch and the third switch, and the connection point between the fifth switch and the sixth switch in series is connected to point O. The low-loss modulation method of the three-level ANPC converter includes: determining the direction of the load current and the magnitude of the modulation wave v ref Based on the direction of the load current and the magnitude of the modulation wave v ref The output level is switched from the P state or the N state to the first state, and the first state is a state in which the second switch, the third switch, the fifth switch, and the sixth switch are turned on and other switches are turned off.

[0007] As an embodiment of the present application, in the above method, based on the direction of the load current and the magnitude of the modulation wave v ref The output level is switched from the P state or the N state to the first state, including:

[0008] When the modulation wave v ref ≥0 and the load current is positive, the output level is sequentially switched from the P state to the second state, the third state, the fourth state, and the first state. The second state is a state in which the first switch, the third switch, and the sixth switch are turned on and other switches are turned off. The third state is a state in which the third switch and the sixth switch are turned on and other switches are turned off. The fourth state is a state in which the third switch, the fifth switch, and the sixth switch are turned on and other switches are turned off.

[0009] When the modulation wave v ref ≥0 and the load current is negative, the output level is sequentially switched from the P state to the second state, the third state, the fifth state, and the first state. The fifth state is a state in which the second switch, the third switch, and the sixth switch are turned on and other switches are turned off.

[0010] When the modulation wave v refWhen < 0 and the load current is positive, the output level sequentially switches from the N state to the sixth state, the seventh state, the eighth state, and the first state. The sixth state is the state where the second switch, the fourth switch, and the fifth switch are turned on and the other switches are turned off; the seventh state is the state where the second switch and the fifth switch are turned on and the other switches are turned off; the eighth state is the state where the second switch, the third switch, and the fifth switch are turned on and the other switches are turned off;

[0011] When the modulation wave v ref < 0 and the load current is negative, the output level sequentially switches from the N state to the sixth state, the seventh state, the ninth state, and the first state. The ninth state is the state where the second switch, the fifth switch, and the sixth switch are turned on and the other switches are turned off.

[0012] As an embodiment of the present application, the low-loss modulation method of the above three-level ANPC converter further includes:

[0013] Based on the modulation wave v ref two auxiliary modulation waves v ref1 and v ref2 are determined: when the modulation wave v ref ≥0, v ref1 = v ref +Δv1, v ref2 = v ref +Δv2; when v ref <0, v ref1 = v ref -Δv1, v ref2 = v ref -Δv2, where the time difference generated by Δv1 is greater than the dead time of the switching tube, and the time difference generated by Δv2 is equal to the time difference generated by Δv1 plus the dead time;

[0014] The switching of the output level from the P state or the N state to the first state based on the direction of the load current and the magnitude of the modulation wave v ref includes:

[0015] When v ref ≥0 and the load current is positive, the output level switches from the P state to the first state. Specifically, when v ref > v c1 , the P level is output, the first switch, the second switch, and the sixth switch are turned on, and the remaining switches are all turned off. The v c1 is the carrier used when v ref ≥0; when v ref < v c1 and v ref1 > vc1 When the second switch is turned off and the third switch is turned on after a dead time, the states of the six switches change to the first switch, the third switch, and the sixth switch being on, and the remaining switches being off; when v ref1 < v c1 and v ref2 > v c1 the first switch is turned off, and the states of the six switches change to the third switch and the sixth switch being on, and the remaining switches being off; after a dead time, the fifth switch is turned on, and the states of the six switches change to the third switch, the fifth switch, and the sixth switch being on, and the remaining switches being off; when v ref2 < v c1 after a dead time, the second switch is turned on, and the states of the six switches change to the first state;

[0016] When v ref ≥ 0 and the load current is negative, the output level switches from the P state to the first state, specifically including: when v ref > v c1 the output is at the P level, the first switch, the second switch, and the sixth switch are turned on, and the remaining switches are off; when v ref < v c1 and v ref1 > v c1 the second switch is turned off, and the third switch is turned on after a dead time, and the states of the six switches change to the first switch, the third switch, and the sixth switch being on, and the remaining switches being off; when v ref1 < v c1 and v ref2 > v c1 the first switch is turned off, and the states of the six switches change to the third switch and the sixth switch being on, and the remaining switches being off; after a dead time, the second switch is turned on, and the states of the six switches change to the second switch, the third switch, and the sixth switch being on; when v ref2 < v c1 after a dead time, the fifth switch is turned on, and the states of the six switches change to the first state;

[0017] When v ref < 0 and the load current is positive, the output level switches from the N state to the first state, specifically including: when v ref < v c2 the output is at the N level, the third switch, the fourth switch, and the fifth switch are turned on, and the remaining switches are off, where v c2 is the carrier used when v ref < 0; when v ref > v c2 and v ref1< v c2 When, the third switch is turned off, and after a dead time, the second switch is turned on. The states of the six switches change to the second, fourth, and fifth switches being on, and the remaining switches are all off; when v ref1 > v c2 and v ref2 < v c2 When, the fourth switch is turned off, and the states of the six switches change to the second and fifth switches being on; after a dead time, the third switch is turned on, and the states of the six switches change to the second, third, and fifth switches being on; when v ref2 > v c2 When, after a dead time, the sixth switch is turned on, and the states of the six switches change to the first state;

[0018] When v ref < 0 and the load current is negative, the output level switches from the N state to the first state, specifically including: when v ref < v c2 When, the N level is output, and the third, fourth, and fifth switches are turned on, and the remaining switches are all off; when v ref > v c2 and v ref1 < v c2 When, the third switch is turned off, and after a dead time, the second switch is turned on. The states of the six switches change to the second, fourth, and fifth switches being on, and the remaining switches are all off; when v ref1 > v c2 and v ref2 < v c2 When, the fourth switch is turned off, and the states of the six switches change to the second and fifth switches being on; after a dead time, the sixth switch is turned on, and the states of the six switches change to the second, fifth, and sixth switches being on; when v ref2 > v c2 When, after a dead time, the third switch is turned on, and the states of the six switches change to the first state.

[0019] As an embodiment of the present application, the second switch and the third switch are SiC or GaN power devices.

[0020] According to a second aspect of the present invention, a low-loss modulation device for a three-level ANPC converter is provided. The three-level ANPC converter includes three-phase bridge arms, and each phase bridge arm includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch. The positive and negative poles of the three-level ANPC converter are point P and point N respectively, the midpoint between point P and point N is point O, a first capacitor is connected in parallel between point P and point O, and a second capacitor is connected in parallel between point O and point N. The first switch, the second switch, the third switch, and the fourth switch are sequentially connected in series between point P and point N. After the fifth switch and the sixth switch are connected in series, they are connected in parallel with the second switch and the third switch, and the connection point between the fifth switch and the sixth switch in series is connected to point O. The low-loss modulation device of the three-level ANPC converter includes: a determination unit for determining the direction of the load current and the magnitude of the modulation wave v ref and the magnitude of the modulation wave v ref ; a modulation unit for switching the output level from the P state or the N state to the first state based on the direction of the load current and the magnitude of the modulation wave v

[0021] As an embodiment of the present application, the above modulation unit includes:

[0022] a first modulation module for, when the modulation wave v ref ≥0 and the load current is positive, switching the output level from the P state to the second state, the third state, the fourth state, and the first state in sequence. The second state is the state in which the first switch, the third switch, and the sixth switch are turned on and other switches are turned off; the third state is the state in which the third switch and the sixth switch are turned on and other switches are turned off; the fourth state is the state in which the third switch, the fifth switch, and the sixth switch are turned on and other switches are turned off;

[0023] a second modulation module for, when the modulation wave v ref ≥0 and the load current is negative, switching the output level from the P state to the second state, the third state, the fifth state, and the first state in sequence. The fifth state is the state in which the second switch, the third switch, and the sixth switch are turned on and other switches are turned off;

[0024] a third modulation module for, when the modulation wave v refWhen <0 and the load current is positive, the output level sequentially switches from the N state to the sixth state, the seventh state, the eighth state, and the first state. The sixth state is the state where the second switch, the fourth switch, and the fifth switch are turned on and the other switches are turned off; the seventh state is the state where the second switch and the fifth switch are turned on and the other switches are turned off; the eighth state is the state where the second switch, the third switch, and the fifth switch are turned on and the other switches are turned off.

[0025] The fourth modulation module is used to, when the modulation wave v ref <0 and the load current is negative, the output level sequentially switches from the N state to the sixth state, the seventh state, the ninth state, and the first state. The ninth state is the state where the second switch, the fifth switch, and the sixth switch are turned on and the other switches are turned off.

[0026] As an embodiment of the present application, the low-loss modulation device of the above three-level ANPC converter further includes:

[0027] The auxiliary wave determination unit is used to determine two auxiliary modulation waves v ref and v ref1 on the basis of the modulation wave v ref2 : when the modulation wave v ref ≥0, v ref1 =v ref +Δv1, v ref2 =v ref +Δv2; when v ref <0, v ref1 =v ref -Δv1, v ref2 =v ref -Δv2, where the time difference generated by Δv1 is greater than the dead time of the switching tube, and the time difference generated by Δv2 is equal to the time difference generated by Δv1 plus the dead time;

[0028] The modulation unit includes:

[0029] The fifth modulation module is used to, when v ref ≥0 and the load current is positive, switch the output level from the P state to the first state. Specifically, when v ref >v c1 , output the P level, the first switch, the second switch, and the sixth switch are turned on, and the rest of the switches are turned off. The v c1 is the carrier used when v ref ≥0; when v ref <v c1 and v ref1 >v c1When the second switch is turned off, the third switch is turned on after a dead time, and the states of the six switches change to the first switch, the third switch, and the sixth switch being turned on, and the remaining switches are all turned off; when v ref1 < v c1 and v ref2 > v c1 , the first switch is turned off, and the states of the six switches change to the third switch and the sixth switch being turned on, and the remaining switches are all turned off; after a dead time, the fifth switch is turned on, and the states of the six switches change to the third switch, the fifth switch, and the sixth switch being turned on, and the remaining switches are all turned off; when v ref2 < v c1 , after a dead time, the second switch is turned on, and the states of the six switches change to the first state;

[0030] The sixth modulation module is used to switch the output level from the P state to the first state when v ref ≥0 and the load current is negative, specifically including: when v ref > v c1 , the P level is output, and the first switch, the second switch, and the sixth switch are turned on, and the remaining switches are all turned off; when v ref < v c1 and v ref1 > v c1 , the second switch is turned off, and the third switch is turned on after a dead time, and the states of the six switches change to the first switch, the third switch, and the sixth switch being turned on, and the remaining switches are all turned off; when v ref1 < v c1 and v ref2 > v c1 , the first switch is turned off, and the states of the six switches change to the third switch and the sixth switch being turned on, and the remaining switches are all turned off; after a dead time, the second switch is turned on, and the states of the six switches change to the second switch, the third switch, and the sixth switch being turned on; when v ref2 < v c1 , after a dead time, the fifth switch is turned on, and the states of the six switches change to the first state;

[0031] The seventh modulation module is used to switch the output level from the N state to the first state when v ref <0 and the load current is positive, specifically including: when v ref < v c2 , the N level is output, and the third switch, the fourth switch, and the fifth switch are turned on, and the remaining switches are all turned off, where v c2 is the carrier used when v ref <0; when v ref > v c2 and vref1 < v c2 When, the third switch is turned off, and after a dead time, the second switch is turned on. The states of the six switches change to the second, fourth, and fifth switches being on, and the remaining switches are all off; when v ref1 > v c2 and v ref2 < v c2 When, the fourth switch is turned off, and the states of the six switches change to the second and fifth switches being on; after a dead time, the third switch is turned on, and the states of the six switches change to the second, third, and fifth switches being on; when v ref2 > v c2 When, after a dead time, the sixth switch is turned on, and the states of the six switches change to the first state;

[0032] An eighth modulation module, configured to switch the output level from the N state to the first state when v ref < 0 and the load current is negative, specifically including: when v ref < v c2 When, the N level is output, and the third, fourth, and fifth switches are turned on, and the remaining switches are all off; when v ref > v c2 and v ref1 < v c2 When, the third switch is turned off, and after a dead time, the second switch is turned on. The states of the six switches change to the second, fourth, and fifth switches being on, and the remaining switches are all off; when v ref1 > v c2 and v ref2 < v c2 When, the fourth switch is turned off, and the states of the six switches change to the second and fifth switches being on; after a dead time, the sixth switch is turned on, and the states of the six switches change to the second, fifth, and sixth switches being on; when v ref2 > v c2 When, after a dead time, the third switch is turned on, and the states of the six switches change to the first state.

[0033] As an embodiment of the present application, the second switch and the third switch are SiC or GaN power devices.

[0034] According to a third aspect of the present invention, a three-level ANPC converter is provided. The three-level ANPC converter includes three-phase bridge arms, and each phase bridge arm includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch. The positive and negative poles of the three-level ANPC converter are point P and point N respectively, and the midpoint between point P and point N is point O. A first capacitor is connected in parallel between point P and point O, and a second capacitor is connected in parallel between point O and point N. The first switch, the second switch, the third switch, and the fourth switch are sequentially connected in series between point P and point N. After the fifth switch and the sixth switch are connected in series, they are connected in parallel with the second switch and the third switch, and the connection point between the fifth switch and the sixth switch in series is connected to point O. The three-level ANPC converter is modulated by using the low-loss modulation method described in any one of claims 1-4.

[0035] According to a fourth aspect of the present invention, an electronic device is provided, which includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the steps of the above method are implemented.

[0036] According to a fifth aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above method are implemented.

[0037] According to a sixth aspect of the present invention, a computer program product is provided, including a computer program / instructions. When the computer program / instructions are executed by a processor, the steps of the above method are implemented.

[0038] It can be seen from the above technical solutions that the three-level ANPC converter, its low-loss modulation method, and modulation device provided by this application, when using the zero-level switch state (i.e., the first state) with parallel loops, while reducing the conduction loss, improving the system working efficiency, and balancing the loss distribution, concentrate all the switching losses on the inner tubes (i.e., the second switch and the third switch). If the inner tubes are replaced with power devices such as SiC and GaN, which have the characteristics of low switching loss and fast switching speed, the advantages of this modulation method can be greatly exerted, the system loss can be further reduced, and the working efficiency can be improved. In addition, the present invention can be applied to any power factor. Regardless of the current direction, the switching losses are always concentrated on the inner tubes. Finally, there is no situation where two pairs of switches act simultaneously in the switching state provided by the present invention, and it is relatively easy to apply in practice. Description of the Drawings

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. In the drawings:

[0040] Figure 1 is a schematic diagram of a single-phase structure of a three-level ANPC converter provided by an embodiment of the present application;

[0041] Figure 2 is a schematic flowchart of a low-loss modulation method for a three-level ANPC converter provided by an embodiment of the present application;

[0042] Figure 3 is a schematic flowchart of switching the output level from the P state or the N state to the first state provided by an embodiment of the present application;

[0043] Figure 4 is a PWM waveform diagram when the load current direction is positive in the positive half cycle of the modulation wave provided by an embodiment of the present application;

[0044] Figure 5 is a PWM waveform diagram when the load current direction is negative in the positive half cycle of the modulation wave provided by an embodiment of the present application;

[0045] Figure 6 is a PWM waveform diagram when the load current direction is positive in the negative half cycle of the modulation wave provided by an embodiment of the present application;

[0046] Figure 7 is a PWM waveform diagram when the load current direction is negative in the negative half cycle of the modulation wave provided by an embodiment of the present application;

[0047] Figure 8 is a schematic diagram of the switching process between P and OO2356 when the load current direction is positive in the positive half cycle of the modulation wave provided by an embodiment of the present application;

[0048] Figure 9 is a schematic diagram of the switching process between P and OO2356 when the load current direction is negative in the positive half cycle of the modulation wave provided by an embodiment of the present application;

[0049] Figure 10 is a schematic diagram of the switching process between N and OO2356 when the load current direction is positive in the negative half cycle of the modulation wave provided by an embodiment of the present application;

[0050] Figure 11 is a schematic diagram of the switching process between N and OO2356 when the load current direction is negative in the negative half cycle of the modulation wave provided by an embodiment of the present application;

[0051] Figure 12 It is the experimental result diagram of the modulation method of the three-level ANPC converter provided by the embodiment of the present application;

[0052] Figure 13 It is the experimental result of the switching process between P and OO2356 when the load current direction is positive during the positive half cycle of the modulation wave provided by the embodiment of the present application;

[0053] Figure 14 It is the experimental result of the switching process between P and OO2356 when the load current direction is negative during the positive half cycle of the modulation wave provided by the embodiment of the present application;

[0054] Figure 15 It is the experimental result of the switching process between N and OO2356 when the load current direction is positive during the negative half cycle of the modulation wave provided by the embodiment of the present application;

[0055] Figure 16 It is the experimental result of the switching process between N and OO2356 when the load current direction is negative during the negative half cycle of the modulation wave provided by the embodiment of the present application;

[0056] Figure 17 It is the structural schematic diagram of the low-loss modulation device of the three-level ANPC converter provided by the embodiment of the present application;

[0057] Figure 18 It is the system composition schematic block diagram of the electronic device provided by the embodiment of the present application. Detailed implementation manners

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer and more understandable, the following further describes the embodiments of the present invention in detail with reference to the accompanying drawings. Herein, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but do not limit the present invention.

[0059] As shown in the present application and the claims, unless the context clearly indicates an exceptional situation, words such as "a", "an", "one", and / or "the" do not specifically refer to the singular, but may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of the clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0060] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that for the sake of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the authorized specification. In all the examples shown and discussed here, any specific values should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it will not be discussed further in subsequent drawings.

[0061] In the description of the present application, it should be understood that the orientation or positional relationships indicated by orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom" are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Without contrary description, these orientation terms do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus should not be construed as limiting the scope of protection of the present application; the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0062] For the convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above" and the like may be used herein to describe the spatial positional relationship between one device or feature and other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the drawings. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." may include both the orientations of "above..." and "below...". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations of the spatial relative descriptions used herein will be made.

[0063] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of differentiating the corresponding components. Without additional statements, the above terms have no special meanings, and thus should not be construed as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some of the terms mentioned in the specification of this application may be selected by the applicant according to his or her judgment, and their detailed meanings are described in the relevant parts of this description. In addition, it is required to understand this application not only through the actual terms used, but also through the meanings implied by each term.

[0064] It should be understood that when a component is referred to as "on another component", "connected to another component", "coupled to another component", or "in contact with another component", it can be directly on, connected to, or coupled to, or in contact with that other component, or there may be an intervening component. In contrast, when a component is referred to as "directly on another component", "directly connected to", "directly coupled to", or "directly in contact with" another component, there is no intervening component. Similarly, when the first component is referred to as "electrically contacting" or "electrically coupled to" the second component, there is an electrical path allowing current to flow between the first component and the second component. The electrical path may include capacitors, coupled inductors, and / or other components allowing current to flow, even if there is no direct contact between the conductive components.

[0065] As Figure 1 shown is a schematic diagram of the single-phase structure of a three-level ANPC converter provided by an embodiment of this application. The three-level ANPC converter includes three-phase bridge arms, and the structure of each phase bridge arm is as Figure 1 shown, and consists of Figure 1 It can be seen that each phase bridge arm includes a first switch (corresponding to S1 and D1), a second switch (corresponding to S2 and D2), a third switch (corresponding to S3 and D3), a fourth switch (corresponding to S4 and D4), a fifth switch (corresponding to S5 and D5), and a sixth switch (corresponding to S6 and D6), that is, each switch is composed of a switching transistor S x and an anti-parallel diode or body diode D x constituted. In this embodiment, each switch can be any switching device such as Si IGBT, Si MOSFET, SiC MOSFET, etc. Preferably, the above second switch and the third switch are SiC or GaN power devices.

[0066] From Figure 1 it can be seen that the positive and negative poles of the above three-level ANPC converter are point P and point N respectively, the midpoint between point P and point N is point O, and a first capacitor (corresponding to C dc1), a second capacitor (corresponding to C) is connected in parallel between point O and point N dc2 ); The first switch, the second switch, the third switch, and the fourth switch are connected in series between point P and point N in sequence. After the fifth switch and the sixth switch are connected in series, they are connected in parallel with the second switch and the third switch, and the connection point between the fifth switch and the sixth switch in series is connected to point O. In this three-level ANPC converter, the first switch and the fourth switch are called outer tubes, the second switch and the third switch are called inner tubes, and the fifth switch and the sixth switch are called clamping tubes. For the convenience of describing this application below, the above first switch to sixth switch are respectively denoted as SW1 to SW6.

[0067] As Figure 2 shown, the low-loss modulation method of the above three-level ANPC converter includes the following steps:

[0068] Step S101: Determine the direction of the load current and the magnitude of the modulation wave v ref . In this embodiment, when determining the direction of the load current, the direction of the load current flowing out of the converter is defined as positive, and the direction of the load current flowing in is defined as negative.

[0069] Step S102: Based on the direction of the load current and the magnitude of the modulation wave v ref , switch the output level from the P state or the N state to the first state, and the first state is the state where SW2, SW3, SW5, and SW6 are turned on and other switches are turned off.

[0070] Preferably, as Figure 3 shown, this step S102 can further include:

[0071] Step S1021: When the modulation wave v ref ≥0 and the load current is positive, the output level is switched from the P state to the second state, the third state, the fourth state, and the first state in sequence. The second state is the state where the first switch, the third switch, and the sixth switch are turned on and other switches are turned off; the third state is the state where the third switch and the sixth switch are turned on and other switches are turned off; the fourth state is the state where the third switch, the fifth switch, and the sixth switch are turned on and other switches are turned off.

[0072] Step S1022: When the modulation wave v ref ≥0 and the load current is negative, the output level is switched from the P state to the second state, the third state, the fifth state, and the first state in sequence. The fifth state is the state where the second switch, the third switch, and the sixth switch are turned on and other switches are turned off.

[0073] Step S1023: When the modulation wave v refWhen <0 and the load current is positive, the output level sequentially switches from the N state to the sixth state, the seventh state, the eighth state, and the first state. The sixth state is the state where the second switch, the fourth switch, and the fifth switch are turned on and the other switches are turned off; the seventh state is the state where the second switch and the fifth switch are turned on and the other switches are turned off; the eighth state is the state where the second switch, the third switch, and the fifth switch are turned on and the other switches are turned off.

[0074] Step S1024: When the modulation wave v ref <0 and the load current is negative, the output level sequentially switches from the N state to the sixth state, the seventh state, the ninth state, and the first state. The ninth state is the state where the second switch, the fifth switch, and the sixth switch are turned on and the other switches are turned off.

[0075] For a clearer description, the above first state will be described as OO 2356 below, the second state as OL 136 below, the third state as OL 36 below, the fourth state as OL 356 below, the fifth state as OL 236 below, the sixth state as OU 245 below, the seventh state as OU 25 below, the eighth state as OU 235 below, the ninth state as OU 256 . Among them, OO represents an output of zero level, and the current flows through the parallel loop of the upper and lower half-bridges; OL represents an output of zero level, and the current flows through the lower half-bridge; OU represents an output of zero level, and the current flows through the upper half-bridge; the numbers represent the switch numbers in the on state. Therefore, the above steps S1021 - S1024 can be further expressed as follows:

[0076] Step S1021: When the modulation wave v ref ≥0 and the load current is positive, the output level sequentially switches from the P state as follows: P → OL 136 → OL 36 → OL 356 → OO 2356 .

[0077] Step S1022: When the modulation wave v ref ≥0 and the load current is negative, the output level sequentially switches from the P state as follows: P → OL 136 → OL 36 → OL 236 → OO 2356 .

[0078] Step S1023: When the modulation wave v ref < 0 and the load current is positive, the output level switches from the N state in the following order: N → OU 245 → OU 25 → OU 235 → OO 2356 .

[0079] Step S1024: When the modulation wave v ref <0 and the load current is negative, the output level switches from the N state in the following order: N → OU 245 → OU 25 → OU 256 → OO 2356 .

[0080] Based on the above definitions, the switch state definitions involved in the modulation method of the three-level ANPC converter provided in this application are shown in Table 1.

[0081] Table 1

[0082]

[0083]

[0084] Further preferably, the low-loss modulation method of the above three-level ANPC converter further includes:

[0085] Determine two auxiliary modulation waves v ref and v ref1 and v ref2 on the basis of the modulation wave v ref ≥0, v ref1 = v ref + Δv1, v ref2 = v ref + Δv2; when the modulation wave v ref <0, v ref1 = v ref - Δv1, v ref2 = v ref - Δv2, where the time difference generated by Δv1 is greater than the dead time of the switching tube, and the time difference generated by Δv2 is equal to the time difference generated by Δv1 plus the dead time.

[0086] And in the above step S102, based on the direction of the load current and the magnitude of the modulation wave v ref , switching the output level from the P state or the N state to OO 2356 includes:

[0087] When v ref≥0 and when the load current is positive, the output level switches from the P state to the first state, specifically including: when v ref > v c1 , the P level is output, SW1, SW2, and SW6 are turned on, and the rest of the switches are turned off. The v c1 is the carrier used when v ref ≥0; when v ref < v c1 and v ref1 > v c1 , SW2 is turned off, and SW3 is turned on after a dead time. The states of the six switches change to SW1, SW3, and SW6 being turned on, and the rest of the switches being turned off, that is, the switch state switches to OL 136 ; when v ref1 < v c1 and v ref2 > v c1 , SW1 is turned off, and the states of the six switches change to SW3 and SW6 being turned on, and the rest of the switches being turned off, that is, the switch state switches to OL 36 ; after a dead time, SW5 is turned on, and the states of the six switches change to SW3, SW5, and SW6 being turned on, and the rest of the switches being turned off, that is, the switch state switches to OL 356 ; when v ref2 < v c1 , after a dead time, SW2 is turned on, and the states of the six switches change to OO 2356 . At this time, the generation method of Pulse Width Modulation (PWM) is as shown in Figure 4 .

[0088] When v ref ≥0 and the load current is negative, the output level switches from the P state to the first state, specifically including: when v ref > v c1 , the P level is output, SW1, SW2, and SW6 are turned on, and the rest of the switches are turned off. The v c1 is the carrier used when v ref ≥0; when v ref < v c1 and v ref1 > v c1 , SW2 is turned off, and SW3 is turned on after a dead time. The states of the six switches change to SW1, SW3, and SW6 being turned on, and the rest of the switches being turned off, that is, the switch state switches to OL 136 ; when v ref1 < v c1 and v ref2 > v c1When SW1 is turned off, the states of the six switches change to SW3 and SW6 being turned on, and the rest of the switches are turned off, that is, the switch state switches to OL. 36 After a dead time, SW2 is turned on, and the states of the six switches change to SW2, SW3, and SW6 being turned on, that is, the switch state switches to OL. 236 When v ref2 < v c1 After a dead time, SW5 is turned on, and the states of the six switches change to OO. 2356 At this time, the PWM generation method is as Figure 5 shown.

[0089] When v ref < 0 and the load current is positive, the output level switches from the N state to the first state, specifically including: when v ref < v c2 the N level is output, SW3, SW4, and SW5 are turned on, and the rest of the switches are turned off. The v c2 is the carrier wave used when v ref < 0; when v ref > v c2 and v ref1 < v c2 SW3 is turned off, and SW2 is turned on after a dead time. The states of the six switches change to SW2, SW4, and SW5 being turned on, and the rest of the switches are turned off, that is, the switch state switches to OU. 245 When v ref1 > v c2 and v ref2 < v c2 SW4 is turned off, and the states of the six switches change to SW2 and SW5 being turned on, that is, the switch state switches to OU. 25 After a dead time, SW3 is turned on, and the states of the six switches change to SW2, SW3, and SW5 being turned on, that is, the switch state switches to OU. 235 When v ref2 > v c2 After a dead time, SW6 is turned on, and the states of the six switches change to OO. 2356 At this time, the PWM generation method is as Figure 6 shown.

[0090] When v ref < 0 and the load current is negative, the output level switches from the N state to the first state, specifically including: when v ref < v c2 the N level is output, SW3, SW4, and SW5 are turned on, and the rest of the switches are turned off. The v c2 is the carrier wave used when v ref < 0;ref > v c2 and v ref1 < v c2 When it is, SW3 is turned off, and SW2 is turned on again after a dead time. The states of the six switches change to SW2, SW4, and SW5 being on, and the rest of the switches are off, that is, the switch state switches to OU 245 ; When v ref1 > v c2 and v ref2 < v c2 When it is, SW4 is turned off, and the states of the six switches change to SW2 and SW5 being on, that is, the switch state switches to OU 25 ; After a dead time, SW6 is turned on, and the states of the six switches change to SW2, SW5, and SW6 being on, that is, the switch state switches to OU 256 ; When v ref2 > v c2 When it is, after a dead time, SW3 is turned on, and the states of the six switches change to OO 2356 . At this time, the generation method of PWM is as Figure 7 shown.

[0091] The modulation method of the present application is described above. Next, the commutation process under the modulation method of the three-level ANPC converter provided by the present invention will be analyzed in detail below.

[0092] When v ref ≥0, the output load current direction is positive, and the commutation process of the output level switching from the P state to OO 2356 is as Figure 8 shown. When the switch state is P, switches S1, S2, and S6 are on. When the switch state switches from P to OL136, switch S2 is hard turned off, and switch S3 is turned on again after a dead time. During the turn-on process, the voltage across S3 is zero, which is a soft turn-on. Then, switch S1 is turned off, and the switch state switches to OL36. Since there is no current flowing through the switch during the turn-off process of S1, it is a soft turn-off. When the switch state switches from OL36 to OL356, switch S5 is turned on. During the turn-on process, there is no current flowing through the switch, which is a soft turn-on. Finally, when the switch state switches from OL356 to OO2356, switch S2 is turned on. During the turn-on process, the voltage across switch S2 is always zero, which is a soft turn-on. Similarly, it can be analyzed that when the output level switches from the OO2356 state to P, only when the switch state switches from OL136 to P, switch S2 is hard turned on and D3 is hard turned off, resulting in switch losses. The rest of the switch state switching processes are all soft-switching processes, and the switch losses can be ignored.

[0093] When v ref ≥0, the output load current direction is negative, and the commutation process of the output level switching from the P state to OO2356 is as Figure 9As shown. When the switch state is P, switches S1, S2, and S6 are turned on. When the switch state switches from P to OL136, switch S2 is softly turned off. After a dead time, switch S3 is hard turned on. Then, switch S1 is turned off, and the switch state switches to OL36. Since there is no current flowing through the switch during the turn-off process of switch S1, it is a soft turn-off. When the switch state switches from OL36 to OL236, switch S2 is turned on, and there is no current flowing through the switch during the turn-on process, so it is a soft turn-on. Then, when the switch state switches from OL236 to OO2356, switch S5 is turned on, and the voltage across switch S5 is always zero during the turn-on process, so it is a soft turn-on. Similarly, it can be analyzed that when the output level switches from the OO2356 state to P, only when the switch state switches from OL136 to P, switch S2 is softly turned on and S3 is hard turned off, resulting in switching losses. The switching processes of the other switch states are all soft-switching processes, and the switching losses can be ignored.

[0094] v ref When v < 0, the commutation process of the output level switching from the N state to the OO2356 state is as Figure 10 、 Figure 11 shown. The analysis process is symmetric to the commutation process of the output level switching from the P state to the OO2356 state described above, and will not be elaborated here, but the protection scope of the present invention should not be limited thereby.

[0095] As can be seen from the above technical solutions, the low-loss modulation method of the three-level ANPC converter provided by this application, when using the zero-level switch state with parallel loops (i.e., the first state), while reducing the conduction loss, improving the system working efficiency, and balancing the loss distribution, concentrates all the switching losses on the inner tubes (i.e., the second switch and the third switch). If the inner tubes are replaced with power devices such as SiC and GaN, which have the characteristics of low switching loss and fast switching speed, the advantages of this modulation method can be greatly exerted, the system loss can be further reduced, and the working efficiency can be improved. In addition, the present invention can be applied to any power factor. Regardless of the current direction, the switching losses are always concentrated on the inner tubes. Finally, there is no situation where two pairs of switches act simultaneously in the switching state provided by the present invention, and it is relatively easy to apply in practice.

[0096] In order to further verify the above beneficial effects, an experimental prototype was built according to the technical solution of the present invention. Under the working conditions of a DC-side voltage of 200V, a carrier frequency of 25kHz, a modulation ratio of 0.805, and a power factor of 0.63, the modulation method of the present invention was experimentally verified, and the results are as Figure 12 shown. According to the modulation wave of the ANPC three-level converter and the instantaneous value of the load output current, the switching state switching methods in the four working states are respectively as Figure 13 、 Figure 14 、 Figure 15 and Figure 16 shown. From Figures 12 - 16The conclusion of the above beneficial effects can be clearly obtained.

[0097] The present invention also provides a low-loss modulation device for a three-level ANPC converter. The three-level ANPC converter includes three-phase bridge arms, and each phase bridge arm includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch. The positive and negative poles of the three-level ANPC converter are P point and N point respectively, and the midpoint between P point and N point is O point. A first capacitor is connected in parallel between P point and O point, and a second capacitor is connected in parallel between O point and N point. The first switch, the second switch, the third switch, and the fourth switch are sequentially connected in series between P and N points. After the fifth switch and the sixth switch are connected in series, they are connected in parallel with the second switch and the third switch, and the connection point between the fifth switch and the sixth switch in series is connected to O point. As Figure 17 shown, the low-loss modulation device for the above three-level ANPC converter includes: a determination unit 170 and a modulation unit 171, which are connected to each other. Among them:

[0098] The determination unit 170 is configured to determine the direction of the load current and the magnitude of the modulation wave v ref of.

[0099] The modulation unit 171 is configured to switch the output level from the P state or the N state to the first state based on the direction of the load current and the magnitude of the modulation wave v ref The first state is a state in which the second switch, the third switch, the fifth switch, and the sixth switch are turned on and other switches are turned off.

[0100] Preferably, the modulation unit includes:

[0101] The first modulation module is configured to, when the modulation wave v ref ≥0 and the load current is positive, switch the output level from the P state to the second state, the third state, the fourth state, and the first state in sequence. The second state is a state in which the first switch, the third switch, and the sixth switch are turned on and other switches are turned off; the third state is a state in which the third switch and the sixth switch are turned on and other switches are turned off; the fourth state is a state in which the third switch, the fifth switch, and the sixth switch are turned on and other switches are turned off;

[0102] The second modulation module is configured to, when the modulation wave v ref ≥0 and the load current is negative, switch the output level from the P state to the second state, the third state, the fifth state, and the first state in sequence. The fifth state is a state in which the second switch, the third switch, and the sixth switch are turned on and other switches are turned off;

[0103] The third modulation module is used to sequentially switch the output level from the N state to the sixth state, the seventh state, the eighth state, and the first state when the modulation wave v ref <0 and the load current is positive. The sixth state is the state where the second switch, the fourth switch, and the fifth switch are turned on and the other switches are turned off; the seventh state is the state where the second switch and the fifth switch are turned on and the other switches are turned off; the eighth state is the state where the second switch, the third switch, and the fifth switch are turned on and the other switches are turned off;

[0104] The fourth modulation module is used to sequentially switch the output level from the N state to the sixth state, the seventh state, the ninth state, and the first state when the modulation wave v ref <0 and the load current is negative. The ninth state is the state where the second switch, the fifth switch, and the sixth switch are turned on and the other switches are turned off.

[0105] Preferably, the low-loss modulation device of the above three-level ANPC converter further includes:

[0106] An auxiliary wave determination unit for determining two auxiliary modulation waves v ref and v ref1 on the basis of the modulation wave v ref2 : when the modulation wave v ref ≥0, v ref1 =v ref +Δv1, v ref2 =v ref +Δv2; when v ref <0, v ref1 =v ref -Δv1, v ref2 =v ref -Δv2, where the time difference generated by Δv1 is greater than the dead time of the switching tube, and the time difference generated by Δv2 is equal to the time difference generated by Δv1 plus the dead time;

[0107] The above modulation unit 171 includes:

[0108] The fifth modulation module is used to switch the output level from the P state to the first state when v ref ≥0 and the load current is positive. Specifically, when v ref >v c1 , the P level is output, the first switch, the second switch, and the sixth switch are turned on, and the rest of the switches are turned off. The v c1 is the carrier when v ref ≥0; when v ref <v c1 and v ref1 >vc1 When the second switch is turned off, the third switch is turned on after a dead time, and the states of the six switches change to the first switch, the third switch, and the sixth switch being on, and the remaining switches are all off; when v ref1 < v c1 and v ref2 > v c1 , the first switch is turned off, and the states of the six switches change to the third switch and the sixth switch being on, and the remaining switches are all off; after a dead time, the fifth switch is turned on, and the states of the six switches change to the third switch, the fifth switch, and the sixth switch being on, and the remaining switches are all off; when v ref2 < v c1 , after a dead time, the second switch is turned on, and the states of the six switches change to the first state;

[0109] The sixth modulation module is used to switch the output level from the P state to the first state when v ref ≥0 and the load current is negative, and specifically includes: when v ref > v c1 , the P level is output, and the first switch, the second switch, and the sixth switch are turned on, and the remaining switches are all off; when v ref < v c1 and v ref1 > v c1 , the second switch is turned off, the third switch is turned on after a dead time, and the states of the six switches change to the first switch, the third switch, and the sixth switch being on, and the remaining switches are all off; when v ref1 < v c1 and v ref2 > v c1 , the first switch is turned off, and the states of the six switches change to the third switch and the sixth switch being on, and the remaining switches are all off; after a dead time, the second switch is turned on, and the states of the six switches change to the second switch, the third switch, and the sixth switch being on; when v ref2 < v c1 , after a dead time, the fifth switch is turned on, and the states of the six switches change to the first state;

[0110] The seventh modulation module is used to switch the output level from the N state to the first state when v ref < 0 and the load current is positive, and specifically includes: when v ref < v c2 , the N level is output, the third switch, the fourth switch, and the fifth switch are turned on, and the remaining switches are all off, and the v c2 is the carrier wave when v ref < v c2 ; when v ref> v c2 and v ref1 < v c2 When, the third switch is turned off, and the second switch is turned on again after a dead time. The states of the six switches change to the second, fourth, and fifth switches being on, and the rest of the switches are off; when v ref1 > v c2 and v ref2 < v c2 When, the fourth switch is turned off, and the states of the six switches change to the second and fifth switches being on; after a dead time, the third switch is turned on, and the states of the six switches change to the second, third, and fifth switches being on; when v ref2 > v c2 When, after a dead time, the sixth switch is turned on, and the states of the six switches change to the first state;

[0111] The eighth modulation module is configured to switch the output level from the N state to the first state when v ref < 0 and the load current is negative, and specifically includes: when v ref < v c2 When, the N level is output, and the third, fourth, and fifth switches are turned on, and the rest of the switches are off; when v ref > v c2 and v ref1 < v c2 When, the third switch is turned off, and the second switch is turned on again after a dead time. The states of the six switches change to the second, fourth, and fifth switches being on, and the rest of the switches are off; when v ref1 > v c2 and v ref2 < v c2 When, the fourth switch is turned off, and the states of the six switches change to the second and fifth switches being on; after a dead time, the sixth switch is turned on, and the states of the six switches change to the second, fifth, and sixth switches being on; when v ref2 > v c2 When, after a dead time, the third switch is turned on, and the states of the six switches change to the first state.

[0112] As an embodiment of the present application, the second switch and the third switch are SiC or GaN power devices.

[0113] The third aspect of the present invention further provides a three-level ANPC converter. The three-level ANPC converter includes three-phase bridge arms. Each phase bridge arm includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch. The positive and negative poles of the three-level ANPC converter are point P and point N respectively. The midpoint between point P and point N is point O. A first capacitor is connected in parallel between point P and point O, and a second capacitor is connected in parallel between point O and point N. The first switch, the second switch, the third switch, and the fourth switch are sequentially connected in series between point P and point N. After the fifth switch and the sixth switch are connected in series, they are connected in parallel with the second switch and the third switch, and the connection point between the fifth switch and the sixth switch in series is connected to point O. The three-level ANPC converter is modulated by using the low-loss modulation method described above.

[0114] As can be seen from the above technical solutions, the three-level ANPC converter, its low-loss modulation method, and modulation device provided by the present application, when using the zero-level switch state (i.e., the first state) with parallel loops, while reducing the conduction loss, improving the system working efficiency, and balancing the loss distribution, concentrate all the switching losses on the inner tubes (i.e., the second switch and the third switch). If the inner tubes are replaced with power devices such as SiC and GaN, which have the characteristics of low switching loss and fast switching speed, the advantages of this modulation method can be greatly exerted, the system loss can be further reduced, and the working efficiency can be improved. In addition, the present invention can be applied to any power factor. Regardless of the current direction, the switching losses are always concentrated on the inner tubes. Finally, there is no situation where two pairs of switches act simultaneously in the switching state provided by the present invention, and it is relatively easy to apply in practice.

[0115] An embodiment of the present invention further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the above method is implemented.

[0116] An embodiment of the present invention further provides a computer program product, including a computer program / instructions. When the computer program / instructions are executed by a processor, the steps of the above method are implemented.

[0117] An embodiment of the present invention further provides a computer-readable storage medium, which stores a computer program for executing the above method.

[0118] As Figure 18 shown, the electronic device 600 may further include: a communication module 110, an input unit 120, an audio processor 130, a display 160, and a power supply 180. It should be noted that the electronic device 600 does not necessarily have to include all the components shown in Figure 18 ; in addition, the electronic device 600 may further include Figure 18For components not shown herein, reference may be made to the prior art.

[0119] As Figure 18 shown, the central processing unit 100, sometimes also referred to as a controller or operation control, may include a microprocessor or other processor device and / or logic device. The central processing unit 100 receives inputs and controls the operations of the various components of the electronic device 600.

[0120] Among them, the memory 140, for example, may be one or more of a buffer, a flash memory, a hard drive, a removable medium, a volatile memory, a non-volatile memory, or other suitable devices. It can store the above information related to failures, and can also store programs for executing relevant information. And the central processing unit 100 can execute the programs stored in the memory 140 to implement information storage or processing, etc.

[0121] The input unit 120 provides inputs to the central processing unit 100. The input unit 120 is, for example, a key or a touch input device. The power supply 180 is used to supply power to the electronic device 600. The display 160 is used to display display objects such as images and texts. The display can be, for example, an LCD display, but is not limited thereto.

[0122] The memory 140 can be a solid-state memory, for example, a read-only memory (ROM), a random access memory (RAM), a SIM card, etc. It can also be such a memory that stores information even when power is off, can be selectively erased and has more data. Examples of such a memory are sometimes referred to as EPROM, etc. The memory 140 can also be some other type of device. The memory 140 includes a buffer memory 141 (sometimes referred to as a buffer). The memory 140 can include an application / function storage section 142, which is used to store application programs and function programs or the processes for operating the electronic device 600 through the central processing unit 100.

[0123] The memory 140 can also include a data storage section 143, which is used to store data, such as contacts, digital data, pictures, sounds, and / or any other data used by the electronic device. The driver storage section 144 of the memory 140 can include various drivers of the electronic device for communication functions and / or for executing other functions of the electronic device (such as a messaging application, an address book application, etc.).

[0124] The communication module 110 is a transmitter / receiver that transmits and receives signals via the antenna 111. The communication module (transmitter / receiver) is coupled to the central processing unit 100 to provide input signals and receive output signals, which can be the same as in the case of a conventional mobile communication terminal.

[0125] Based on different communication technologies, in the same electronic device, multiple communication modules 110 can be provided, such as a cellular network module, a Bluetooth module, and / or a wireless local area network module, etc. The communication module (transmitter / receiver) is also coupled to the speaker 131 and the microphone 132 via the audio processor 130 to provide an audio output via the speaker 131 and receive an audio input from the microphone 132, so as to implement normal telecommunication functions. The audio processor 130 can include any suitable buffers, decoders, amplifiers, etc. Additionally, the audio processor 130 is also coupled to the central processor 100, enabling recording on the device through the microphone 132 and playing the sounds stored on the device through the speaker 131.

[0126] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0127] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in Figure 1 one or more of the processes Figure 1 or multiple processes and / or blocks

[0128] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device that implements the functions specified in Figure 1 one or more of the processes Figure 1 or multiple processes and / or blocks

[0129] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are executed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions for implementing the steps of the process Figure 1 one process or a plurality of processes and / or blocks Figure 1 steps for the functions specified in one block or a plurality of blocks.

[0130] In the present invention, specific embodiments are used to illustrate the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. At the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A low-loss modulation method for a three-level ANPC converter. The three-level ANPC converter includes three-phase bridge arms. Each phase bridge arm includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch. The positive and negative poles of the three-level ANPC converter are point P and point N respectively. The midpoint between point P and point N is point O. A first capacitor is connected in parallel between point P and point O, and a second capacitor is connected in parallel between point O and point N. The first switch, the second switch, the third switch, and the fourth switch are sequentially connected in series between point P and point N. After the fifth switch and the sixth switch are connected in series, they are connected in parallel with the second switch and the third switch, and the connection point between the fifth switch and the sixth switch in series is connected to point O. It is characterized in that, The low-loss modulation method of the three-level ANPC converter includes: Determine the direction of the load current and the magnitude of the modulating wave v ref ; Based on the direction of the load current and the magnitude of the modulation wave v ref switch the output level from the P state or the N state to the first state, where the first state is the state in which the second switch, the third switch, the fifth switch, and the sixth switch are turned on and the other switches are turned off.

2. The low-loss modulation method of the three-level ANPC converter according to claim 1, characterized in that, Based on the direction of the load current and the magnitude of the modulation wave v ref to switch the output level from the P state or the N state to the first state includes: When the modulation wave v ref ≥ 0 and the load current is positive, the output level is sequentially switched from the P state to the second state, the third state, the fourth state, and the first state. The second state is the state in which the first switch, the third switch, and the sixth switch are turned on and the other switches are turned off; the third state is the state in which the third switch and the sixth switch are turned on and the other switches are turned off; the fourth state is the state in which the third switch, the fifth switch, and the sixth switch are turned on and the other switches are turned off; When the modulation wave v ref ≥ 0 and the load current is negative, the output level is sequentially switched from the P state to the second state, the third state, the fifth state, and the first state in order. The fifth state is the state in which the second switch, the third switch, and the sixth switch are turned on and the other switches are turned off; When the modulation wave v ref < 0 and the load current is positive, the output level is sequentially switched from the N state to the sixth state, the seventh state, the eighth state, and the first state. The sixth state is the state in which the second switch, the fourth switch, and the fifth switch are turned on and the other switches are turned off; the seventh state is the state in which the second switch and the fifth switch are turned on and the other switches are turned off; the eighth state is the state in which the second switch, the third switch, and the fifth switch are turned on and the other switches are turned off; When the modulation wave v ref < 0 and the load current is negative, the output level is sequentially switched from the N state to the sixth state, the seventh state, the ninth state, and the first state. The ninth state is the state in which the second switch, the fifth switch, and the sixth switch are turned on and the other switches are turned off.

3. The low-loss modulation method of the three-level ANPC converter according to claim 1, characterized in that The low-loss modulation method of the three-level ANPC converter further includes: Based on the modulation wave v ref , determine two auxiliary modulation waves v ref1 and v ref2 : When the modulation wave v ref ≥0, v ref1 = v ref + Δv1, v ref2 = v ref + Δv2; when v ref <0, v ref1 = v ref - Δv1, v ref2 = v ref - Δv2, where the time difference generated by Δv1 is greater than the dead time of the switching tube, and the time difference generated by Δv2 is equal to the time difference generated by Δv1 plus the dead time; Based on the direction of the load current and the magnitude of the modulation wave v ref The switching of the output level from the P state or the N state to the first state includes: When v ref ≥ 0 and the load current is positive, the output level switches from the P state to the first state, specifically including: when v ref > v c1 , the output P level is output, the first switch, the second switch, and the sixth switch are turned on, and the remaining switches are all turned off. The v c1 is the carrier used when v ref ≥ 0; when v ref < v c1 and v ref1 > v c1 , the second switch is turned off, and the third switch is turned on after a dead time. The states of the six switches change to the first switch, the third switch, and the sixth switch being turned on, and the remaining switches are all turned off; when v ref1 < v c1 and v ref2 > v c1 , the first switch is turned off, and the states of the six switches change to the third switch and the sixth switch being turned on, and the remaining switches are all turned off; after a dead time, the fifth switch is turned on, and the states of the six switches change to the third switch, the fifth switch, and the sixth switch being turned on, and the remaining switches are all turned off; when v ref2 < v c1 , after a dead time, the second switch is turned on, and the states of the six switches change to the first state; When v ref ≥ 0 and the load current is negative, the output level switches from the P state to the first state, specifically including: when v ref > v c1 , the P level is output, the first switch, the second switch, and the sixth switch are turned on, and the remaining switches are all turned off; when v ref < v c1 and v ref1 > v c1 , the second switch is turned off, and the third switch is turned on after a dead time, and the states of the six switches change to the first switch, the third switch, and the sixth switch being turned on, and the remaining switches are all turned off; when v ref1 < v c1 and v ref2 > v c1 , the first switch is turned off, and the states of the six switches change to the third switch and the sixth switch being turned on, and the remaining switches are all turned off; after a dead time, the second switch is turned on, and the states of the six switches change to the second switch, the third switch, and the sixth switch being turned on; when v ref2 < v c1 , after a dead time, the fifth switch is turned on, and the states of the six switches change to the first state; When v ref < 0 and the load current is positive, the output level switches from the N state to the first state, specifically including: when v ref < v c2 , the output N level, the third switch, the fourth switch and the fifth switch are turned on, and the rest of the switches are turned off. The v c2 is the carrier used when v ref < 0; when v ref > v c2 and v ref1 < v c2 , the third switch is turned off, and the second switch is turned on after a dead time. The states of the six switches change to the second switch, the fourth switch and the fifth switch being turned on, and the rest of the switches being turned off; when v ref1 > v c2 and v ref2 < v c2 , the fourth switch is turned off, and the states of the six switches change to the second switch and the fifth switch being turned on; after a dead time, the third switch is turned on, and the states of the six switches change to the second switch, the third switch and the fifth switch being turned on; when v ref2 > v c2 , after a dead time, the sixth switch is turned on, and the states of the six switches change to the first state; When v ref < 0 and the load current is negative, the output level switches from the N state to the first state, specifically including: when v ref < v c2 , the N level is output, the third switch, the fourth switch, and the fifth switch are turned on, and the rest of the switches are turned off; when v ref > v c2 and v ref1 < v c2 , the third switch is turned off, and the second switch is turned on after a dead time. The states of the six switches change to the second switch, the fourth switch, and the fifth switch being turned on, and the rest of the switches being turned off; when v ref1 > v c2 and v ref2 < v c2 , the fourth switch is turned off, and the states of the six switches change to the second switch and the fifth switch being turned on; after a dead time, the sixth switch is turned on, and the states of the six switches change to the second switch, the fifth switch, and the sixth switch being turned on; when v ref2 > v c2 , after a dead time, the third switch is turned on, and the states of the six switches change to the first state.

4. The low-loss modulation method of the three-level ANPC converter according to claim 1, characterized in that The second switch and the third switch are SiC or GaN power devices.

5. A low-loss modulation device for a three-level ANPC converter, the three-level ANPC converter comprising three-phase bridge arms, each phase bridge arm including a first switch, a second switch, a third switch, a fourth switch, a fifth switch and a sixth switch, the positive and negative poles of the three-level ANPC converter being point P and point N respectively, the midpoint between point P and point N being point O, a first capacitor being connected in parallel between point P and point O, and a second capacitor being connected in parallel between point O and point N; the first switch, the second switch, the third switch and the fourth switch are sequentially connected in series between point P and point N, the fifth switch and the sixth switch are connected in series and then connected in parallel with the second switch and the third switch, and the connection point between the fifth switch and the sixth switch in series is connected to point O, characterized in that, The low-loss modulation device of the three-level ANPC converter includes: A determining unit, configured to determine the direction of a load current and the magnitude of a modulation wave v ref ; A modulation unit, configured to switch an output level from a P state or an N state to a first state based on a direction of the load current and a magnitude of the modulation wave v ref such that the second switch, the third switch, the fifth switch, and the sixth switch are turned on and other switches are turned off.

6. The low-loss modulation device of the three-level ANPC converter according to claim 5, characterized in that The modulation unit includes: The first modulation module is configured to, when the modulation wave v ref ≥ 0 and the load current is positive, sequentially switch the output level from the P state to the second state, the third state, the fourth state, and the first state in order. The second state is the state in which the first switch, the third switch, and the sixth switch are turned on and the other switches are turned off; the third state is the state in which the third switch and the sixth switch are turned on and the other switches are turned off; the fourth state is the state in which the third switch, the fifth switch, and the sixth switch are turned on and the other switches are turned off; The second modulation module is configured to, when the modulation wave v ref ≥ 0 and the load current is negative, sequentially switch the output level from the P state to the second state, the third state, the fifth state, and the first state. The fifth state is the state in which the second switch, the third switch, and the sixth switch are turned on while the other switches are turned off; The third modulation module is used to, when the modulation wave v ref < 0 and the load current is positive, sequentially switch the output level from the N state to the sixth state, the seventh state, the eighth state, and the first state in sequence. The sixth state is the state in which the second switch, the fourth switch, and the fifth switch are turned on and the other switches are turned off; the seventh state is the state in which the second switch and the fifth switch are turned on and the other switches are turned off; the eighth state is the state in which the second switch, the third switch, and the fifth switch are turned on and the other switches are turned off; The fourth modulation module is configured to, when the modulation wave v ref < 0 and the load current is negative, sequentially switch the output level from the N state to the sixth state, the seventh state, the ninth state, and the first state in sequence. The ninth state is the state in which the second switch, the fifth switch, and the sixth switch are turned on and the other switches are turned off.

7. The low-loss modulation device of the three-level ANPC converter according to claim 5, characterized in that, The low-loss modulation device of the three-level ANPC converter further includes: An auxiliary wave determination unit, configured to determine two auxiliary modulation waves v ref and v ref1 based on the modulation wave v ref2 : when the modulation wave v ref ≥0, v ref1 =v ref +Δv1, v ref2 =v ref +Δv2; when v ref <0, v ref1 =v ref -Δv1, v ref2 =v ref -Δv2, where the time difference generated by Δv1 is greater than the dead time of the switching tube, and the time difference generated by Δv2 is equal to the time difference generated by Δv1 plus the dead time; The modulation unit includes: The fifth modulation module is used to switch the output level from the P state to the first state when v ref ≥0 and the load current is positive. Specifically, it includes: when v ref >v c1 , the P level is output, the first switch, the second switch, and the sixth switch are turned on, and the rest of the switches are turned off. The v c1 is the carrier used when v ref ≥0; when v ref <v c1 and v ref1 >v c1 , the second switch is turned off, and the third switch is turned on after a dead time. The states of the six switches change to the first switch, the third switch, and the sixth switch being turned on, and the rest of the switches being turned off; when v ref1 <v c1 and v ref2 >v c1 , the first switch is turned off, and the states of the six switches change to the third switch and the sixth switch being turned on, and the rest of the switches being turned off; after a dead time, the fifth switch is turned on, and the states of the six switches change to the third switch, the fifth switch, and the sixth switch being turned on, and the rest of the switches being turned off; when v ref2 <v c1 , after a dead time, the second switch is turned on, and the states of the six switches change to the first state; The sixth modulation module is used to switch the output level from the P state to the first state when v ref ≥ 0 and the load current is negative, specifically including: when v ref > v c1 , the P level is output, the first switch, the second switch, and the sixth switch are turned on, and the rest of the switches are turned off; when v ref < v c1 and v ref1 > v c1 , the second switch is turned off, the third switch is turned on after a dead time, and the states of the six switches change to the first switch, the third switch, and the sixth switch being turned on, and the rest of the switches being turned off; when v ref1 < v c1 and v ref2 > v c1 , the first switch is turned off, and the states of the six switches change to the third switch and the sixth switch being turned on, and the rest of the switches being turned off; after a dead time, the second switch is turned on, and the states of the six switches change to the second switch, the third switch, and the sixth switch being turned on; when v ref2 < v c1 , after a dead time, the fifth switch is turned on, and the states of the six switches change to the first state; The seventh modulation module is used to switch the output level from the N state to the first state when v ref < 0 and the load current is positive, specifically including: when v ref < v c2 , output the N level, turn on the third switch, the fourth switch and the fifth switch, and turn off the rest of the switches. The v c2 is the carrier used when v ref < 0; when v ref > v c2 and v ref1 < v c2 , turn off the third switch, and turn on the second switch after a dead time. The states of the six switches change to the second switch, the fourth switch and the fifth switch being on, and the rest of the switches being off; when v ref1 > v c2 and v ref2 < v c2 , turn off the fourth switch, and the states of the six switches change to the second switch and the fifth switch being on; after a dead time, turn on the third switch, and the states of the six switches change to the second switch, the third switch and the fifth switch being on; when v ref2 > v c2 , turn on the sixth switch after a dead time, and the states of the six switches change to the first state; The eighth modulation module is used to switch the output level from the N state to the first state when v ref < 0 and the load current is negative, and specifically includes: when v ref < v c2 , output the N level, turn on the third switch, the fourth switch, and the fifth switch, and turn off the remaining switches; when v ref > v c2 and v ref1 < v c2 , turn off the third switch, and turn on the second switch after a dead time, and the states of the six switches change to the second switch, the fourth switch, and the fifth switch are turned on, and the remaining switches are turned off; when v ref1 > v c2 and v ref2 < v c2 , turn off the fourth switch, and the states of the six switches change to the second switch and the fifth switch are turned on; after a dead time, turn on the sixth switch, and the states of the six switches change to the second switch, the fifth switch, and the sixth switch are turned on; when v ref2 > v c2 , turn on the third switch after a dead time, and the states of the six switches change to the first state.

8. The low-loss modulation device of the three-level ANPC converter according to claim 5, characterized in that, The second switch and the third switch are SiC or GaN power devices.

9. A three-level ANPC converter, the three-level ANPC converter includes three-phase bridge arms, each phase bridge arm includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch and a sixth switch. The positive and negative poles of the three-level ANPC converter are point P and point N respectively, the midpoint between point P and point N is point O, a first capacitor is connected in parallel between point P and point O, and a second capacitor is connected in parallel between point O and point N; the first switch, the second switch, the third switch and the fourth switch are sequentially connected in series between point P and point N, the fifth switch and the sixth switch are connected in series and then connected in parallel with the second switch and the third switch, and the connection point between the fifth switch and the sixth switch in series is connected to point O, characterized in that, The three-level ANPC converter is modulated by using the low-loss modulation method according to any one of claims 1-4.

10. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, the steps of the method according to any one of claims 1-4 are implemented.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, the steps of the method according to any one of claims 1-4 are implemented.

12. A computer program product, comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, the steps of the method according to any one of claims 1-4 are implemented.

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