Modulation method and device of active neutral point clamped three-level inverter power device

Abstract

The invention provides a modulation method and device of an active neutral-point-clamped three-level inverter power device, and belongs to the technical field of inverter modulation.The method comprises the steps that under the condition that each phase of bridge arm of an active neutral-point-clamped three-level inverter has a current flowing path, the on-off state of each phase of bridge arm of the active neutral-point-clamped three-level inverter is determined; according to the on-off state of each phase of bridge arm of the active neutral-point clamped three-level inverter and the corresponding current circulation path, determining the on-off state of a power device with relatively low on-off loss; the method comprises the following steps: determining a high-frequency tube and a fundamental frequency tube of each phase of bridge arm on the basis of a switching state with relatively small switching loss of a power device, comparing modulation waves corresponding to the high-frequency tube and the fundamental frequency tube with triangular carrier waves, and outputting PWM (Pulse-Width Modulation) pulse to drive an inverter to generate a corresponding switching state on the basis of a comparison result. The method can solve the problems that an existing inverter modulation method cannot reduce the overall loss of the inverter, the commutation path analysis is complex, and the control difficulty is high.

Description

Technical Field

[0001] The present invention relates to the technical field of inverter modulation, and in particular to a modulation method and device for an active neutral point clamped three-level inverter power device. Background Art

[0002] The three-level converter has the advantages of low voltage and current distortion rate, small voltage stress on the switch tube, and low dv / dt, and has been widely used in the fields of new energy grid connection, AC speed regulation, energy storage system, etc. Compared with the traditional diode clamped and flying capacitor inverters, the active midpoint clamped three-level inverter uses active devices to achieve midpoint clamping, which is easy to achieve balanced distribution control of power device losses, and is receiving more and more attention.

[0003] Under the conventional modulation strategy, the loss of the inner and outer tubes of the active neutral point clamped three-level inverter is uneven, and the junction temperature difference of the power device is large, which restricts the further increase of the switching frequency. In order to optimize the loss distribution of the power device of the three-level active neutral point clamped inverter and reduce the overall loss of the inverter, the existing research literature uses the redundant zero-level state of ANPC to balance the loss between power devices, and changes the commutation process and loss characteristics of the power device by selecting different zero-level states to achieve a balanced distribution of the power device loss. This method cannot reduce the overall loss of the inverter, and has the disadvantages of complex commutation path analysis and high control difficulty. Summary of the invention

[0004] In view of this, it is necessary to provide a modulation method and device for an active neutral point clamped three-level inverter power device to solve the technical problems that the existing inverter modulation method cannot reduce the overall loss of the inverter and has complex commutation path analysis and high control difficulty.

[0005] In order to solve the above problems, on the one hand, the present invention provides a modulation method for an active neutral point clamped three-level inverter power device, comprising: In the case where each phase bridge arm of the active neutral point clamped three-level inverter has a current flow path, determining a switching state of each phase bridge arm of the active neutral point clamped three-level inverter; According to the switching state of each phase bridge arm of the active neutral point clamped three-level inverter and the corresponding current flow path, a switching state with a smaller switching loss of the power device is determined; Based on the switching state with smaller switching loss of the power device, the high-frequency tube and the base-frequency tube of each phase bridge arm are determined, the modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier, and the PWM pulse is output based on the comparison result to drive the inverter to generate the corresponding switching state.

[0006] In a possible implementation, determining a switching state of each phase bridge arm of an active neutral point clamped three-level inverter includes: Based on the number of on / off power devices on each phase bridge arm of the active neutral point clamped three-level inverter, the switching state of each phase bridge arm is determined.

[0007] In a possible implementation, the switch state of each phase bridge arm includes: a first type of switch state and a second type of switch state; The first type of switch state includes: the number of power devices in the on state and the number of power devices in the off state on each phase bridge arm are both 3; The second type of switch state includes: the number of power devices turned on in each phase bridge arm is 2, and the number of power devices turned off in each phase bridge arm is 4.

[0008] In a possible implementation, the switching state of the power device with low switching loss satisfies the following conditions: In any switching state, there is a bidirectional current flow path; and, The voltage stress of the power device is 1 / 6 of the input voltage of the active midpoint clamped three-level inverter or 1 / 3 of the input voltage of the active midpoint clamped three-level inverter, and the switching loss of the power device is reduced to 1 / 3 or 2 / 3 of the initial state; and, The voltage stress of the anti-parallel diode is 1 / 6 of the input voltage of the active midpoint clamped three-level inverter or 1 / 3 of the input voltage of the active midpoint clamped three-level inverter, and the reverse recovery loss of the power device is reduced to 1 / 3 or 2 / 3 of the initial state.

[0009] In a possible implementation, each phase bridge arm of the active neutral point clamped three-level inverter includes six groups of switches, each group of switches is composed of power devices; the first group of switches, the fifth group of switches, the sixth group of switches and the fourth group of switches are connected in series in sequence; the combination formed by the second group of switches and the third group of switches in series is connected in parallel with the combination formed by the fifth group of switches and the sixth group of switches in series; The modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier wave, and a PWM pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, including: When the reference voltage of the modulation wave is greater than zero and greater than the triangular carrier, the output PWM pulse drives the first and fifth groups of switches to turn on, and controls the remaining groups of switches to turn off.

[0010] In a possible implementation, the modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier, and a PWM pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, further comprising: When the reference voltage of the modulation wave is greater than zero and less than the triangular carrier, or the reference voltage of the modulation wave is less than zero and greater than the triangular carrier, the output PWM pulse drives the second and third groups of switches to turn on, and controls the remaining groups of switches to turn off.

[0011] In a possible implementation, the modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier, and a PWM pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, further comprising: When the reference voltage of the modulation wave is less than zero and less than the carrier, the output PWM pulse drives the fourth and sixth switch groups to turn on, and the remaining switch groups are all turned off.

[0012] In a possible implementation, the carrier phases of all power devices are the same.

[0013] In a possible implementation, the carrier generation counting mode of all power devices is a continuous increase and decrease mode.

[0014] On the other hand, the present invention also provides a modulation device for an active neutral point clamped three-level inverter power device, comprising: A first switch state determination module is used to determine the switch state of each phase bridge arm of the active neutral point clamped three-level inverter when each phase bridge arm of the active neutral point clamped three-level inverter has a current flow path; A second switch state determination module is used to determine a switch state with a smaller switching loss of the power device according to the switch state of each phase bridge arm of the active neutral point clamped three-level inverter and the corresponding current flow path; The switch control module is used to determine the high-frequency tube and the base-frequency tube of each phase bridge arm based on the switch state with smaller switching loss of the power device, compare the modulation wave corresponding to the high-frequency tube and the base-frequency tube with the triangular carrier, and output PWM pulses based on the comparison result to drive the inverter to generate the corresponding switch state.

[0015] The beneficial effects of adopting the above implementation method are as follows: the modulation method and device of the power device of the active midpoint clamped three-level inverter provided by the present invention, the modulation method determines the switching state with less switching loss of the power device according to the switching state of each phase bridge arm of the active midpoint clamped three-level inverter and the corresponding current flow path; based on the switching state with less switching loss of the power device, the high-frequency tube and the base-frequency tube of each phase bridge arm are determined, the modulation wave corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier, and the PWM pulse is output based on the comparison result to drive the inverter to generate the corresponding switching state. The modulation method provided by the present invention reduces the voltage stress of the power device by shutting down more power devices to participate in the DC bus voltage division when the active midpoint clamped three-level inverter outputs the same level state, thereby reducing the switching loss of the power device of the active midpoint clamped three-level inverter. The modulation method adopted by the present invention does not change the topological structure of the active neutral point clamped three-level inverter, does not increase the complexity of the control system, and is easy to implement by software programming, thereby solving the technical problems that the existing inverter modulation method cannot reduce the overall loss of the inverter and has complex commutation path analysis and high control difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A flow chart of an embodiment of a modulation method for an active neutral point clamped three-level inverter power device provided by the present invention; Figure 2 A topological diagram of a single bridge arm of an active neutral point clamped three-level inverter provided by the present invention; Figure 3 It is a schematic diagram of the voltage stress and current stress waveforms of T1-T6 tubes under the base frequency modulation method of the outer tube and the high frequency modulation method of the inner tube of the active midpoint clamped three-level inverter in the existing modulation method; Figure 4 It is a schematic diagram of the voltage stress and current stress waveforms of T1-T6 tubes under the active midpoint clamped three-level inverter inner tube base frequency and outer tube high frequency modulation method in the existing modulation method; Figure 5 A schematic diagram of voltage stress and current stress waveforms of tubes T1-T6 under the base frequency modulation method of the inner tube and high frequency modulation method of the outer tube of the active midpoint clamped three-level inverter in the modulation method provided by the present invention; Figure 6 A principle block diagram of an embodiment of a modulation device for an active neutral point clamped three-level inverter power device provided by the present invention; Figure 7 A schematic structural diagram of an embodiment of an electronic device provided by the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0019] In the description of the embodiments of the present application, unless otherwise specified, “plurality” means two or more than two.

[0020] The terms "including" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product or equipment comprising a series of steps or modules is not necessarily limited to those steps or modules clearly listed, but may include other steps or modules not clearly listed or inherent to these processes, methods, products or equipment.

[0021] The naming or numbering of the steps in the embodiments of the present invention does not mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The execution order of the named or numbered process steps can be changed according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved.

[0022] Reference to an "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] The present invention provides a modulation method and device for an active neutral point clamped three-level inverter power device, which are described below respectively.

[0024] like Figure 1 As shown, the present invention provides a modulation method for an active neutral point clamped three-level inverter power device, comprising: S101, determining a switching state of each phase bridge arm of the active neutral point clamped three-level inverter when each phase bridge arm of the active neutral point clamped three-level inverter has a current flow path; S102, determining a switching state with a smaller switching loss of a power device according to a switching state of each phase bridge arm of the active neutral point clamped three-level inverter and a corresponding current flow path; S103, based on the switching state of the power device with smaller switching loss, determine the high-frequency tube and the base-frequency tube of each phase bridge arm, compare the modulation waves corresponding to the high-frequency tube and the base-frequency tube with the triangular carrier, and output PWM pulses based on the comparison result to drive the inverter to generate a corresponding switching state.

[0025] It can be understood that the modulation method of the active neutral point clamped three-level inverter power device provided by the present invention can reduce the power device loss of the active neutral point clamped three-level inverter power device.

[0026] Figure 2 The topology diagram of a single bridge arm of an active neutral point clamped three-level inverter (3L-ANPC), where T1, T2, T3, and T4 are external power devices of the inverter; and T5 and T6 are internal power devices of the inverter.

[0027] Figure 3 It is a schematic diagram of the voltage stress and current stress waveforms of T1-T6 tubes under the 3L-ANPC inverter outer tube base frequency and inner tube high frequency modulation method in the existing modulation method; Figure 4 The following is a schematic diagram of the voltage stress and current stress waveforms of T1-T6 tubes under the existing modulation method of the 3L-ANPC inverter inner tube base frequency and outer tube high frequency modulation. In the two traditional modulation methods, the voltage stress of the power device is 1 / 2U dc , U dc Input voltage for the active neutral point clamped three-level inverter.

[0028] Figure 5 The voltage stress and current stress waveforms of T1-T6 tubes under the proposed modulation method that can reduce the power device loss of 3L-ANPC inverter are shown in Figure 2. Under the modulation method, the voltage stress of the power device is divided into three cases: 1 / 2U dc 、1 / 6U dc 、1 / 3U dc .

[0029] The present invention has the following technical effects: The present invention reduces the voltage stress of the power devices by shutting down more power devices to participate in the DC bus voltage division when the active neutral point clamped three-level inverter outputs the same level, thereby reducing the switching loss of the power devices of the active neutral point clamped three-level inverter. The technical solution adopted by the present invention has the following advantages: the topology of the 3L-ANPC inverter is not changed, the complexity of the control system is not increased, and it is easy to implement by software programming.

[0030] In some embodiments, determining a switching state of each phase bridge arm of an active neutral point clamped three-level inverter includes: Based on the number of on / off power devices on each phase bridge arm of the active neutral point clamped three-level inverter, the switching state of each phase bridge arm is determined.

[0031] In some embodiments, the switch state of each phase bridge arm includes: a first type of switch state and a second type of switch state; The first type of switch state includes: the number of power devices in the on state and the number of power devices in the off state on each phase bridge arm are both 3; The second type of switch state includes: the number of power devices turned on in each phase bridge arm is 2, and the number of power devices turned off in each phase bridge arm is 4.

[0032] In some embodiments, the switching state of the power device with low switching loss satisfies the following conditions: In any switching state, there is a bidirectional current flow path; and, The voltage stress of the power device is 1 / 6 of the input voltage of the active midpoint clamped three-level inverter or 1 / 3 of the input voltage of the active midpoint clamped three-level inverter, and the switching loss of the power device is reduced to 1 / 3 or 2 / 3 of the initial state; and, The voltage stress of the anti-parallel diode is 1 / 6 of the input voltage of the active midpoint clamped three-level inverter or 1 / 3 of the input voltage of the active midpoint clamped three-level inverter, and the reverse recovery loss of the power device is reduced to 1 / 3 or 2 / 3 of the initial state.

[0033] In some embodiments, each phase bridge arm of the active neutral point clamped three-level inverter includes six groups of switches, each group of switches is composed of power devices; the first group of switches, the fifth group of switches, the sixth group of switches and the fourth group of switches are connected in series in sequence; the combination formed by the second group of switches and the third group of switches in series is connected in parallel with the combination formed by the fifth group of switches and the sixth group of switches in series; The modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier wave, and a PWM (pulse width modulation) pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, including: When the reference voltage of the modulation wave is greater than zero and greater than the triangular carrier, the output PWM pulse drives the first and fifth groups of switches to turn on, and controls the remaining groups of switches to turn off.

[0034] It is understandable that if Figure 2 As shown, the first group of switches corresponds to the power device T1, the second group of switches corresponds to the power device T2, the third group of switches corresponds to the power device T3, the fourth group of switches corresponds to the power device T4, the fifth group of switches corresponds to the power device T5, and the sixth group of switches corresponds to the power device T6.

[0035] In some embodiments, the modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier, and a PWM pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, further comprising: When the reference voltage of the modulation wave is greater than zero and less than the triangular carrier, or the reference voltage of the modulation wave is less than zero and greater than the triangular carrier, the output PWM pulse drives the second and third groups of switches to turn on, and controls the remaining groups of switches to turn off.

[0036] In some embodiments, the modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier, and a PWM pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, further comprising: When the reference voltage of the modulation wave is less than zero and less than the carrier, the output PWM pulse drives the fourth and sixth switch groups to turn on, and the remaining switch groups are all turned off.

[0037] In some embodiments, the carrier phases of all power devices are the same, and the carrier generation counting method of all power devices is a continuous increase and decrease mode.

[0038] In some embodiments, a modulation method of an active neutral point clamped three-level inverter power device comprises the following steps: Step 1, under the premise of ensuring that each phase bridge arm of the active neutral point clamped three-level inverter has a current flow path, list all its valid switching states; Step 2, according to the switching state of each phase bridge arm of the active neutral point clamped three-level inverter and its corresponding current flow path, determining the switching state with smaller switching loss of the power device; Step 3, according to the switch state selected in step 2, the high-frequency tube and the base-frequency tube of each phase bridge arm are determined, and after comparing the modulated wave with the corresponding triangular carrier wave, a PWM pulse is output to drive the inverter to generate a corresponding switch state.

[0039] The specific process of step 1 is as follows: Step 1.1: Each phase of the active neutral point clamped three-level inverter can output three levels of P, 0, and N. Each output level corresponds to a variety of power device switching states. According to the number of devices on and off in each phase bridge arm and the voltage stress of the power device does not exceed 1 / 2U dc Divided into two types of switch states, U dc is the input voltage of the active neutral point clamped three-level inverter. The first type of switch state is that the number of power devices in each phase bridge arm that are in the on and off states at the same time is 3. The switch state table is shown in Table 1: Table 1: First category switch status

[0040] 1 represents that the power device is in the on state, and 0 represents that the power device is in the off state.

[0041] Step 1.2: The second type of switching state is that the number of power devices in each phase bridge arm in the on state is 2, and the number of power devices in the off state is 4. Since the second type of switching state has more power devices participating in the DC bus voltage division, the voltage stress of the power devices in this switching state is smaller. The switching state table is shown in Table 2: Table 2: Second type of switch status

[0042] 1 represents that the power device is in the on state, and 0 represents that the power device is in the off state.

[0043] Step 2: Select the switching state that minimizes power device loss according to the following principles: (1) In any switching state, there is a bidirectional current flow path; (2) The voltage stress of the power device is 1 / 6U dc or 1 / 3U dc , and its switching loss is reduced to 1 / 3 or 2 / 3 of the original; (3) The voltage stress of the anti-parallel diode is 1 / 6U dc or 1 / 3U dc , U dc The input voltage of the active neutral point clamped three-level inverter is reduced to 1 / 3 or 2 / 3 of the original value.

[0044] The specific process of step 3 is as follows: based on the switch state selected in step 2, after comparing the modulation wave with the triangular carrier, a PWM pulse is output to drive the inverter to generate a corresponding switch state.

[0045] When the reference voltage is greater than zero and greater than the carrier, power devices T1 and T5 are turned on, that is, the first and fifth groups of switches are turned on, and the remaining power devices are turned off; when the reference voltage is greater than zero and less than the carrier, power devices T2 and T3 are turned on, that is, the second and third groups of switches are turned on, and the remaining power devices are turned off; when the reference voltage is less than zero and greater than the carrier, power devices T2 and T3 are turned on, and the remaining power devices are turned off; when the reference voltage is less than zero and less than the carrier, power devices T4 and T6 are turned on, that is, the fourth and sixth groups of switches are turned on, and the remaining power devices are turned off. The carrier phases of all power devices are the same, and the carrier generation counting method is a continuous increase and decrease mode.

[0046] like Figure 6 As shown, the present invention also provides a modulation device 600 of an active neutral point clamped three-level inverter power device, comprising: A first switch state determination module 601 is used to determine the switch state of each phase bridge arm of the active neutral point clamped three-level inverter when each phase bridge arm of the active neutral point clamped three-level inverter has a current flow path; A second switch state determination module 602, configured to determine a switch state with a smaller switching loss of a power device according to the switch state of each phase bridge arm of the active neutral point clamped three-level inverter and the corresponding current flow path; The switch control module 603 is used to determine the high-frequency tube and the base-frequency tube of each phase bridge arm based on the switch state with smaller switching loss of the power device, compare the modulation wave corresponding to the high-frequency tube and the base-frequency tube with the triangular carrier, and output PWM pulses based on the comparison result to drive the inverter to generate the corresponding switch state.

[0047] The modulation device of the active neutral point clamped three-level inverter power device provided in the above embodiment can realize the technical solution described in the above embodiment of the modulation method of the active neutral point clamped three-level inverter power device. The specific implementation principles of the above modules or units can refer to the corresponding contents in the above embodiment of the modulation method of the active neutral point clamped three-level inverter power device, which will not be repeated here.

[0048] like Figure 7 As shown, the present invention also provides an electronic device 700. The electronic device 700 includes a processor 701, a memory 702 and a display 703. Figure 7 Only some components of the electronic device 700 are shown, but it should be understood that it is not required to implement all of the components shown, and more or fewer components may be implemented instead.

[0049] In some embodiments, the memory 702 may be an internal storage unit of the electronic device 700, such as a hard disk or memory of the electronic device 700. In other embodiments, the memory 702 may also be an external storage device of the electronic device 700, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the electronic device 700.

[0050] Furthermore, the memory 702 may include both an internal storage unit of the electronic device 700 and an external storage device. The memory 702 is used to store application software installed in the electronic device 700 and various data.

[0051] In some embodiments, the processor 701 may be a central processing unit (CPU), a microprocessor or other data processing chip, and is used to run program codes or process data stored in the memory 702, such as the modulation method of the active neutral point clamped three-level inverter power device in the present invention.

[0052] In some embodiments, the display 703 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, an OLED (Organic Light-Emitting Diode) touch device, etc. The display 703 is used to display information on the electronic device 700 and to display a visual user interface. The components 701-703 of the electronic device 700 communicate with each other via a system bus.

[0053] In some embodiments of the present invention, when the processor 701 executes the modulation program of the active neutral point clamped three-level inverter power device in the memory 702, the following steps may be implemented: In the case where each phase bridge arm of the active neutral point clamped three-level inverter has a current flow path, determining a switching state of each phase bridge arm of the active neutral point clamped three-level inverter; According to the switching state of each phase bridge arm of the active neutral point clamped three-level inverter and the corresponding current flow path, a switching state with a smaller switching loss of the power device is determined; Based on the switching state with smaller switching loss of the power device, the high-frequency tube and the base-frequency tube of each phase bridge arm are determined, the modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier, and the PWM pulse is output based on the comparison result to drive the inverter to produce the corresponding switching state.

[0054] It should be understood that: when the processor 701 executes the modulation program of the active neutral point clamped three-level inverter power device in the memory 702, in addition to the above functions, other functions can be realized, and the details can be referred to the description of the above corresponding method embodiments.

[0055] Furthermore, the embodiment of the present invention does not specifically limit the type of the electronic device 700 mentioned, and the electronic device 700 may be a portable electronic device such as a mobile phone, a tablet computer, a personal digital assistant (PDA), a wearable device, a laptop computer, etc. Exemplary embodiments of portable electronic devices include but are not limited to portable electronic devices equipped with IOS, Android, Microsoft or other operating systems. The above-mentioned portable electronic device may also be other portable electronic devices, such as a laptop computer with a touch-sensitive surface (e.g., a touch panel). It should also be understood that in some other embodiments of the present invention, the electronic device 700 may not be a portable electronic device, but a desktop computer with a touch-sensitive surface (e.g., a touch panel).

[0056] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the modulation method of the active neutral point clamped three-level inverter power device provided by the above methods is implemented, and the method comprises: In the case where each phase bridge arm of the active neutral point clamped three-level inverter has a current flow path, determining a switching state of each phase bridge arm of the active neutral point clamped three-level inverter; According to the switching state of each phase bridge arm of the active neutral point clamped three-level inverter and the corresponding current flow path, a switching state with a smaller switching loss of the power device is determined; Based on the switching state with smaller switching loss of the power device, the high-frequency tube and the base-frequency tube of each phase bridge arm are determined, the modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier, and the PWM pulse is output based on the comparison result to drive the inverter to generate the corresponding switching state.

[0057] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0058] The modulation method and device of the active neutral point clamped three-level inverter power device provided by the present invention are introduced in detail above. The principle and implementation mode of the present invention are explained by using specific examples in this article. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A modulation method for an active neutral point clamped three-level inverter power device, characterized in that: include: In the case where each phase bridge arm of the active neutral point clamped three-level inverter has a current flow path, determining a switching state of each phase bridge arm of the active neutral point clamped three-level inverter; According to the switching state of each phase bridge arm of the active neutral point clamped three-level inverter and the corresponding current flow path, a switching state with a smaller switching loss of the power device is determined; Based on the switching state with smaller switching loss of the power device, the high-frequency tube and the base-frequency tube of each phase bridge arm are determined, the modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier, and the PWM pulse is output based on the comparison result to drive the inverter to produce the corresponding switching state.

2. The modulation method of the active neutral point clamped three-level inverter power device according to claim 1, characterized in that: Determine the switching state of each phase bridge arm of the active neutral point clamped three-level inverter, including: Based on the number of on / off power devices on each phase bridge arm of the active neutral point clamped three-level inverter, the switching state of each phase bridge arm is determined.

3. The modulation method of the active neutral point clamped three-level inverter power device according to claim 2, characterized in that: The switch state of each phase bridge arm includes: a first type of switch state and a second type of switch state; The first type of switch state includes: the number of power devices in the on state and the number of power devices in the off state on each phase bridge arm are both 3; The second type of switch state includes: the number of power devices turned on in each phase bridge arm is 2, and the number of power devices turned off in each phase bridge arm is 4.

4. The modulation method of the active neutral point clamped three-level inverter power device according to claim 1, characterized in that: The switching state of the power device with small switching loss meets the following conditions: In any switching state, there is a bidirectional current flow path; and, The voltage stress of the power device is 1 / 6 of the input voltage of the active midpoint clamped three-level inverter or 1 / 3 of the input voltage of the active midpoint clamped three-level inverter, and the switching loss of the power device is reduced to 1 / 3 or 2 / 3 of the initial state; and, The voltage stress of the anti-parallel diode is 1 / 6 of the input voltage of the active midpoint clamped three-level inverter or 1 / 3 of the input voltage of the active midpoint clamped three-level inverter, and the reverse recovery loss of the power device is reduced to 1 / 3 or 2 / 3 of the initial state.

5. The modulation method of the active neutral point clamped three-level inverter power device according to any one of claims 1 to 4, characterized in that: Each phase bridge arm of the active neutral point clamped three-level inverter includes six groups of switches, each of which is composed of power devices; the first group of switches, the fifth group of switches, the sixth group of switches and the fourth group of switches are connected in series in sequence; the combination formed by the second group of switches and the third group of switches in series is connected in parallel with the combination formed by the fifth group of switches and the sixth group of switches in series; The modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier wave, and a PWM pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, including: When the reference voltage of the modulation wave is greater than zero and greater than the triangular carrier, the output PWM pulse drives the first and fifth groups of switches to turn on, and controls the remaining groups of switches to turn off.

6. The modulation method of the active neutral point clamped three-level inverter power device according to claim 5, characterized in that: The modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier wave, and a PWM pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, and further includes: When the reference voltage of the modulation wave is greater than zero and less than the triangular carrier, or the reference voltage of the modulation wave is less than zero and greater than the triangular carrier, the output PWM pulse drives the second and third groups of switches to turn on, and controls the remaining groups of switches to turn off.

7. The modulation method of the active neutral point clamped three-level inverter power device according to claim 5, characterized in that: The modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with the triangular carrier wave, and a PWM pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, and further includes: When the reference voltage of the modulation wave is less than zero and less than the carrier, the output PWM pulse drives the fourth and sixth switch groups to turn on, and the remaining switch groups are all turned off.

8. The modulation method of the active neutral point clamped three-level inverter power device according to claim 5, characterized in that: The carrier phase is the same for all power devices.

9. The modulation method of the active neutral point clamped three-level inverter power device according to claim 8, characterized in that: The carrier generation counting method of all power devices is a continuous increase and decrease mode.

10. A modulation device for an active neutral point clamped three-level inverter power device, characterized in that: include: A first switch state determination module is used to determine the switch state of each phase bridge arm of the active neutral point clamped three-level inverter when each phase bridge arm of the active neutral point clamped three-level inverter has a current flow path; A second switch state determination module is used to determine a switch state with a smaller switching loss of the power device according to the switch state of each phase bridge arm of the active neutral point clamped three-level inverter and the corresponding current flow path; The switch control module is used to determine the high-frequency tube and the base-frequency tube of each phase bridge arm based on the switch state with smaller switching loss of the power device, compare the modulation wave corresponding to the high-frequency tube and the base-frequency tube with the triangular carrier, and output PWM pulses based on the comparison result to drive the inverter to generate the corresponding switch state.

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