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

Abstract

The present invention provides a modulation method and device for power devices in an active neutral point clamped three-level inverter, belonging to the field of inverter modulation technology. The method comprises: determining the switching state of each phase arm of the active neutral point clamped three-level inverter when each phase arm of the active neutral point clamped three-level inverter has a current flow path; determining a switching state with minimal switching loss for the power device based on the switching state of each phase arm of the active neutral point clamped three-level inverter and the corresponding current flow path; determining the high-frequency transistor and the fundamental frequency transistor of each phase arm based on the switching state with minimal switching loss for the power device; comparing the modulation waves corresponding to the high-frequency transistor and the fundamental frequency transistor with a triangular carrier wave; and outputting a PWM pulse based on the comparison result to drive the inverter to generate the corresponding switching state. The present invention can solve the problems of existing inverter modulation methods that cannot reduce the overall loss of the inverter and have complex commutation path analysis and high control difficulty.

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] Three-level converters offer advantages such as low voltage and current distortion, minimal voltage stress on switching transistors, and low dv / dt. They are widely used in fields such as renewable energy grid integration, AC speed regulation, and energy storage systems. Active neutral-point-clamped three-level inverters, compared to traditional diode-clamped and flying-capacitor inverters, utilize active devices to achieve neutral-point clamping, facilitating balanced power device loss distribution and control. Consequently, they are attracting increasing attention.

[0003] Under conventional modulation strategies, active neutral point clamped (ANPC) three-level inverters suffer from uneven losses between the inner and outer transistors, leading to significant differences in junction temperature across the power devices and restricting further increases in switching frequency. To optimize the power device loss distribution and reduce overall inverter losses, existing research utilizes the redundant zero-level states of the ANPC to balance losses across power devices. By selecting different zero-level states, these approaches alter the commutation process and loss characteristics of the power devices to achieve a balanced distribution of power device losses. However, these approaches fail to reduce overall inverter losses and suffer from 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 active neutral point clamped three-level inverter power devices 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:

[0006] 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;

[0007] 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, the switching state with the lowest switching loss of the power device is determined;

[0008] Based on the switching state of the power device with smaller switching loss, 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 based on the comparison result, a PWM pulse is output to drive the inverter to generate the corresponding switching state.

[0009] In one possible implementation, determining a switching state of each phase arm of an active neutral point clamped three-level inverter includes:

[0010] The switching state of each phase bridge arm is determined based on the number of on-off power devices on each phase bridge arm of the active neutral point clamped three-level inverter.

[0011] In a possible implementation, the switching state of each phase bridge arm includes: a first type of switching state and a second type of switching state;

[0012] The first type of switching 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;

[0013] The second type of switching 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.

[0014] In one possible implementation, the switching state of the power device with low switching loss satisfies the following conditions:

[0015] In any switching state, there is a bidirectional current flow path; and,

[0016] The voltage stress of the power device is 1 / 6 of the input voltage of the active neutral point clamped three-level inverter or 1 / 3 of the input voltage of the active neutral point 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,

[0017] The voltage stress of the anti-parallel diode is 1 / 6 of the input voltage of the active neutral point clamped three-level inverter or 1 / 3 of the input voltage of the active neutral point 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.

[0018] In one possible implementation, each phase 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 of the second group of switches and the third group of switches in series is connected in parallel with the combination of the fifth group of switches and the sixth group of switches in series;

[0019] The method comprises comparing the modulation waves corresponding to the high-frequency tube and the base-frequency tube with the triangular carrier wave, and outputting PWM pulses based on the comparison result to drive the inverter to generate a corresponding switching state, including:

[0020] 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.

[0021] In a possible implementation, the modulation waves corresponding to the high-frequency tube and the baseband tube are compared with a triangular carrier wave, and a PWM pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, further comprising:

[0022] When the reference voltage of the modulation wave is greater than zero and less than the triangular carrier, or when 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.

[0023] In a possible implementation, the modulation waves corresponding to the high-frequency tube and the baseband tube are compared with a triangular carrier wave, and a PWM pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, further comprising:

[0024] 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 groups of switches to turn on, and the remaining groups of switches are all turned off.

[0025] In a possible implementation, the carrier phases of all power devices are the same.

[0026] In a possible implementation, the carrier generation counting mode of all power devices is a continuous increase and decrease mode.

[0027] On the other hand, the present invention also provides a modulation device for an active neutral point clamped three-level inverter power device, comprising:

[0028] a first switching state determining module, configured to determine the 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;

[0029] A second switching state determination module is configured to determine a switching state with lower switching loss of the power device 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;

[0030] 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 switching state of the power device with smaller switching loss, 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 results to drive the inverter to generate the corresponding switching state.

[0031] The beneficial effects of the above implementation are as follows: the modulation method and apparatus for power devices in an active neutral point clamped three-level inverter provided by the present invention determine a switching state with minimal switching loss for the power device based on the switching state and corresponding current flow path of each phase bridge arm of the active neutral point clamped three-level inverter; based on the switching state with minimal switching loss for the power device, determine the high-frequency transistor and baseband transistor for each phase bridge arm; compare the modulation waves corresponding to the high-frequency transistor and baseband transistor with a triangular carrier; and output PWM pulses based on the comparison result to drive the inverter to produce the corresponding switching state. The modulation method provided by the present invention reduces voltage stress on the power devices by shutting down more power devices to participate in DC bus voltage division when the active neutral point clamped three-level inverter outputs the same level, thereby reducing switching losses in the power devices of the active neutral point clamped three-level inverter. The modulation method adopted by the present invention does not change the topology of the active neutral point clamped three-level inverter, does not increase the complexity of the control system, and is easy to implement through software programming, thereby solving the technical problems of existing inverter modulation methods that cannot reduce the overall loss of the inverter and have complex commutation path analysis and high control difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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.

[0033] 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;

[0034] Figure 2 A topological diagram of a single bridge arm of the active neutral point clamped three-level inverter provided by the present invention;

[0035] Figure 3 Schematic diagram of the voltage stress and current stress waveforms of transistors T1-T6 under the base frequency modulation method of the outer transistor and high frequency modulation method of the inner transistor of the active neutral point clamped three-level inverter in the existing modulation method;

[0036] Figure 4 Schematic diagram of the voltage stress and current stress waveforms of transistors T1-T6 under the existing modulation method of active neutral point clamped three-level inverter with base frequency modulation of inner transistor and high frequency modulation of outer transistor;

[0037] Figure 5 Schematic diagram of the voltage stress and current stress waveforms of transistors T1-T6 under the active neutral point clamped three-level inverter's base frequency modulation method for the inner transistor and high frequency modulation method for the outer transistor in the modulation method provided by the present invention;

[0038] Figure 6 A functional 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;

[0039] Figure 7 This is a schematic structural diagram of an embodiment of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0040] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0041] In the description of the embodiments of the present application, unless otherwise specified, “a plurality of” means two or more.

[0042] 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 device comprising a series of steps or modules is not necessarily limited to those steps or modules explicitly listed, but may include other steps or modules not explicitly listed or inherent to these processes, methods, products or devices.

[0043] 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.

[0044] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0045] The present invention provides a modulation method and device for an active neutral point clamped three-level inverter power device, which are described below.

[0046] like Figure 1 As shown, the present invention provides a modulation method for an active neutral point clamped three-level inverter power device, comprising:

[0047] S101. Determine 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.

[0048] 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;

[0049] S103. Based on the switching state of the power device with the smallest 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 the corresponding switching state.

[0050] It can be understood that the modulation method of the power device of the active neutral point clamped three-level inverter provided by the present invention can reduce the power device loss of the active neutral point clamped three-level inverter.

[0051] Figure 2 The topology diagram of a single bridge arm of an active neutral point clamped three-level inverter (3L-ANPC) is shown in Figure 1, where T1, T2, T3, and T4 are external power transistors of the inverter; T5 and T6 are internal power transistors of the inverter.

[0052] Figure 3 Schematic diagram of the voltage stress and current stress waveforms of T1-T6 transistors under the existing modulation method of the outer tube fundamental frequency and inner tube high frequency modulation of the 3L-ANPC inverter; Figure 4 The following is a schematic diagram of the voltage stress and current stress waveforms of the T1-T6 transistors under the existing modulation method of the 3L-ANPC inverter's internal transistor base frequency and external transistor high frequency modulation methods. In the two traditional modulation methods, the voltage stress on the power devices is 1 / 2U dc , U dc is the input voltage of the active neutral point clamped three-level inverter.

[0053] Figure 5 The voltage stress and current stress waveforms of T1-T6 tubes under the proposed modulation method to reduce the power device loss of 3L-ANPC inverter are shown in the figure. Under the modulation method, the voltage stress borne by the power device is divided into three cases: 1 / 2U dc , 1 / 6U dc , 1 / 3U dc .

[0054] The present invention has the following technical effects:

[0055] This invention reduces the voltage stress on the power devices by shutting down more power devices to participate in DC bus voltage division when the output voltages of the active neutral point clamped three-level inverter are the same. This reduces the switching losses of the power devices in the active neutral point clamped three-level inverter by shutting down more power devices when the inverter outputs are at the same voltage level. The technical solution employed by this invention has the following advantages: it does not change the 3L-ANPC inverter topology, does not increase the complexity of the control system, and is easy to implement through software programming.

[0056] In some embodiments, determining a switching state of each phase arm of an active neutral point clamped three-level inverter includes:

[0057] The switching state of each phase bridge arm is determined based on the number of on-off power devices on each phase bridge arm of the active neutral point clamped three-level inverter.

[0058] In some embodiments, the switching state of each phase bridge arm includes: a first type of switching state and a second type of switching state;

[0059] The first type of switching 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;

[0060] The second type of switching 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.

[0061] In some embodiments, the switching state of the power device with low switching loss satisfies the following conditions:

[0062] In any switching state, there is a bidirectional current flow path; and,

[0063] The voltage stress of the power device is 1 / 6 of the input voltage of the active neutral point clamped three-level inverter or 1 / 3 of the input voltage of the active neutral point 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,

[0064] The voltage stress of the anti-parallel diode is 1 / 6 of the input voltage of the active neutral point clamped three-level inverter or 1 / 3 of the input voltage of the active neutral point 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.

[0065] 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 comprising power devices; the first group of switches, the fifth group of switches, the sixth group of switches, and the fourth group of switches are sequentially connected in series; the combination of the second group of switches and the third group of switches in series is connected in parallel with the combination of the fifth group of switches and the sixth group of switches in series;

[0066] 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:

[0067] 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.

[0068] 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.

[0069] In some embodiments, the modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with a triangular carrier wave, and a PWM pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, further comprising:

[0070] When the reference voltage of the modulation wave is greater than zero and less than the triangular carrier, or when 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.

[0071] In some embodiments, the modulation waves corresponding to the high-frequency tube and the base-frequency tube are compared with a triangular carrier wave, and a PWM pulse is output based on the comparison result to drive the inverter to generate a corresponding switching state, further comprising:

[0072] 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 groups of switches to turn on, and the remaining groups of switches are all turned off.

[0073] In some embodiments, the carrier phases of all power devices are the same, and the carrier generation counting mode of all power devices is a continuous increase and decrease mode.

[0074] In some embodiments, a modulation method for an active neutral point clamped three-level inverter power device includes the following steps:

[0075] Step 1: Enumerate all valid switching states of the active neutral point clamped three-level inverter, ensuring that each phase bridge arm has a current flow path;

[0076] Step 2: determining a switching state with a smaller switching loss of a power device 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;

[0077] Step 3: Determine the high-frequency tube and base-frequency tube of each phase bridge arm according to the switch state selected in step 2, compare the modulated wave with the corresponding triangular carrier, and output PWM pulses to drive the inverter to generate the corresponding switch state.

[0078] The specific process of step 1 is as follows:

[0079] Step 1.1: Each phase of the active neutral point clamped three-level inverter can output three levels: P, 0, and N. Each output level corresponds to a variety of power device switching states. The number of devices on and off in each phase bridge arm and the voltage stress of the power device should not exceed 1 / 2U dc Divided into two types of switching states, U dc is the input voltage of the active neutral point clamped three-level inverter. The first type of switching state is that the number of power devices in each phase arm that are in the on and off states at the same time is 3. The switching state table is shown in Table 1:

[0080] Table 1: First category switch status

[0081]

[0082] 1 represents that the power device is in the on state, and 0 represents that the power device is in the off state.

[0083] Step 1.2: The second 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 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 relatively small. The switching state table is shown in Table 2:

[0084] Table 2: Second type of switch status

[0085]

[0086] 1 represents that the power device is in the on state, and 0 represents that the power device is in the off state.

[0087] Step 2: Select the switching state that minimizes power device loss based on the following principles:

[0088] (1) In any switching state, there is a bidirectional current flow path;

[0089] (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;

[0090] (3) The voltage stress of the anti-parallel diode is 1 / 6U dc or 1 / 3U dc , Udc The input voltage of the active neutral point clamped three-level inverter is reduced to 1 / 3 or 2 / 3 of the original value.

[0091] The specific process of step 3 is as follows: based on the switching state optimized in step 2, the modulation wave is compared with the triangular carrier, and a PWM pulse is output to drive the inverter to generate a corresponding switching state.

[0092] 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 phase of all power devices is the same, and the carrier generation counting method is a continuous increase and decrease mode.

[0093] like Figure 6 As shown, the present invention further provides a modulation device 600 for an active neutral point clamped three-level inverter power device, comprising:

[0094] A first switching state determining module 601 is configured to determine the 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;

[0095] A second switching state determining module 602 is configured to determine a switching state with a smaller switching loss of a power device 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;

[0096] The switch control module 603 is used to determine the high-frequency tube and the baseband tube of each phase bridge arm based on the switching state of the power device with the smallest switching loss, compare the modulation waves corresponding to the high-frequency tube and the baseband tube with the triangular carrier, and output PWM pulses based on the comparison result to drive the inverter to generate the corresponding switching state.

[0097] The modulation device for an active neutral point clamped three-level inverter power device provided in the above embodiment can implement the technical solution described in the above embodiment of the modulation method for an active neutral point clamped three-level inverter power device. The specific implementation principles of the above modules or units can be found in the corresponding contents of the above embodiment of the modulation method for an active neutral point clamped three-level inverter power device, and will not be repeated here.

[0098] like Figure 7As 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 of the components of the electronic device 700 are shown, but it should be understood that it is not required to implement all of the shown components, and more or fewer components may be implemented instead.

[0099] 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.

[0100] 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.

[0101] In some embodiments, the processor 701 may be a central processing unit (CPU), a microprocessor, or other data processing chip, configured to execute program code stored in the memory 702 or process data, such as the modulation method of the active neutral point clamped three-level inverter power device in the present invention.

[0102] In some embodiments, display 703 can be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. Display 703 is used to display information on electronic device 700 and to display a visual user interface. Components 701-703 of electronic device 700 communicate with each other via a system bus.

[0103] 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:

[0104] 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;

[0105] 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, the switching state with the lowest switching loss of the power device is determined;

[0106] Based on the switching state of the power device with smaller switching loss, 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 based on the comparison result, a PWM pulse is output to drive the inverter to generate the corresponding switching state.

[0107] It should be understood that, when executing the modulation program of the active neutral point clamped three-level inverter power device in the memory 702 , the processor 701 may implement other functions in addition to the above functions. For details, please refer to the description of the corresponding method embodiment above.

[0108] Furthermore, the embodiments of the present invention do not specifically limit the type of electronic device 700 mentioned. Electronic device 700 may be a portable electronic device such as a mobile phone, tablet computer, personal digital assistant (PDA), wearable device, or laptop computer. Exemplary embodiments of portable electronic devices include, but are not limited to, portable electronic devices running iOS, Android, Microsoft, or other operating systems. The portable electronic devices mentioned above 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 other embodiments of the present invention, electronic device 700 may not be a portable electronic device, but rather a desktop computer with a touch-sensitive surface (e.g., a touch panel).

[0109] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for modulating a power device of an active neutral point clamped three-level inverter provided by the above methods is implemented. The method comprises:

[0110] 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;

[0111] 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, the switching state with the lowest switching loss of the power device is determined;

[0112] Based on the switching state of the power device with smaller switching loss, 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 based on the comparison result, a PWM pulse is output to drive the inverter to generate the corresponding switching state.

[0113] Those skilled in the art will appreciate that all or part of the process steps of the above-described embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, such as a magnetic disk, an optical disk, a read-only memory, or a random access memory.

[0114] The above describes in detail the modulation method and apparatus for the active neutral point clamped three-level inverter power device provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will appreciate that, based on the concept of the present invention, there may be changes in the specific implementation methods and scope of application. In summary, the contents of this specification should not be construed 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: 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; 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, the switching state with the lowest switching loss of the power device is determined; Based on the switching state of the power device with the lowest switching loss, 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 based on the comparison result, PWM pulses are output to drive the inverter to generate the corresponding switching state; The switching state of each phase bridge arm includes: a first-class switching state and a second-class switching state; The first type of switching 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 switching 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; The switching state of the power device with low 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 neutral point clamped three-level inverter or 1 / 3 of the input voltage of the active neutral point 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 neutral point clamped three-level inverter or 1 / 3 of the input voltage of the active neutral point 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; 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 of the second group of switches and the third group of switches in series is connected in parallel with the combination of the fifth group of switches and the sixth group of switches in series; The method comprises comparing the modulation waves corresponding to the high-frequency tube and the base-frequency tube with the triangular carrier wave, and outputting PWM pulses 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; 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, further comprising: When the reference voltage of the modulation wave is greater than zero and less than the triangular carrier, or when 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; 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, 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 groups of switches to turn on, and the remaining groups of switches are all turned off.

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 leg of the active neutral point clamped three-level inverter, including: The switching state of each phase bridge arm is determined based on the number of on-off power devices on each phase bridge arm of the active neutral point clamped three-level inverter.

3. The modulation method of the active neutral point clamped three-level inverter power device according to claim 1, characterized in that: The carrier phase is the same for all power devices.

4. The modulation method of the active neutral point clamped three-level inverter power device according to claim 3, characterized in that: The carrier generation counting mode of all power devices is continuous increase and decrease mode.

5. A modulation device for an active neutral point clamped three-level inverter power device, characterized in that: include: a first switching state determining module, configured to determine the 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; A second switching state determination module is configured to determine a switching state with lower switching loss of the power device 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 switch control module is used to determine the high-frequency transistor and the base-frequency transistor of each phase bridge arm based on the switching state of the power device with the lowest switching loss, compare the modulation waves corresponding to the high-frequency transistor and the base-frequency transistor with the triangular carrier, and output PWM pulses based on the comparison result to drive the inverter to generate the corresponding switching state; The switching state of each phase bridge arm includes: a first-class switching state and a second-class switching state; The first type of switching 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 switching 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; The switching state of the power device with low 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 neutral point clamped three-level inverter or 1 / 3 of the input voltage of the active neutral point 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 neutral point clamped three-level inverter or 1 / 3 of the input voltage of the active neutral point 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; 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 of the second group of switches and the third group of switches in series is connected in parallel with the combination of the fifth group of switches and the sixth group of switches in series; The method comprises comparing the modulation waves corresponding to the high-frequency tube and the base-frequency tube with the triangular carrier wave, and outputting PWM pulses 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; 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, further comprising: When the reference voltage of the modulation wave is greater than zero and less than the triangular carrier, or when 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; 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, 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 groups of switches to turn on, and the remaining groups of switches are all turned off.

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