Variable frequency converter-based automatic bypass method and device, variable frequency converter and storage medium

Abstract

The application relates to an automatic bypass method and device based on a frequency converter, the frequency converter and a storage medium, and the method comprises the following steps: if a master control unit receives fault information reported by a power unit, the master control unit determines a target bypass strategy according to preconfigured bypass parameters, bypasses the fault power unit according to the target bypass strategy, adjusts carrier interval division values of multiple power units, recalibrates modulation wave parameters and carrier parameters according to the number of residual power units after bypassing, generates a target driving signal based on the recalibrated modulation wave and carrier parameters, so that the corresponding load of the frequency converter can normally operate. Through real-time fault detection and determination of a bypass strategy, the frequency converter can quickly respond when a power unit fails, avoids expansion of the fault, and makes the frequency converter work through cascading of different numbers of power units, thereby improving the reliability and stability of the frequency converter.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of frequency converters, and in particular to an automatic bypass method and device based on a frequency converter, a frequency converter and a storage medium. BACKGROUND

[0002] Frequency converters are widely used in motor drive control. A frequency converter can realize precise control of motor speed and torque by adjusting output frequency and voltage, thereby improving the operating efficiency and energy-saving effect of the motor. Due to the complex use environment of high-power frequency converters, the frequency converter may face various electrical and thermal faults in the actual application process, such as overheating, overcurrent, short circuit and the like. At present, the frequency converter fault problem is usually handled by manual intervention, but this method is slow and inefficient, and there is a possibility of response delay and human operation error.

[0003] Therefore, how to provide an automatic bypass technical solution to improve the reliability and stability of the frequency converter has become a technical problem to be solved by those skilled in the art. It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, and therefore can include information that does not constitute prior art known to those skilled in the art. SUMMARY

[0004] In view of the above, the present application provides an automatic bypass method and device based on a frequency converter, a frequency converter and a storage medium, which aims to solve the above technical problems.

[0005] In a first aspect, the present application provides an automatic bypass method based on a frequency converter, wherein the frequency converter comprises a master control unit and a plurality of power units in communication connection with the master control unit, and the method comprises:

[0006] If the master control unit receives the fault information reported by the power unit, the master control unit determines a target bypass strategy according to the pre-configured bypass parameters, wherein the target bypass strategy comprises an asymmetric bypass strategy and a symmetric bypass strategy;

[0007] According to the target bypass strategy, the faulty power unit is bypassed, and the carrier interval division value of the plurality of power units is adjusted;

[0008] According to the number of remaining power units after bypassing, the modulation wave parameters and carrier parameters are recalibrated;

[0009] Based on the recalibrated modulation wave and carrier parameters, a target drive signal is generated to enable the corresponding load of the frequency converter to operate normally.

[0010] In a second aspect, the present application provides an automatic bypass device based on a frequency converter, wherein the device comprises:

[0011] A determination module is configured to determine a target bypass strategy based on pre-configured bypass parameters upon receiving fault information reported by a power unit, wherein the target bypass strategy includes an asymmetric bypass strategy and a symmetric bypass strategy;

[0012] Bypass module: used for bypassing the faulty power unit according to the target bypass strategy and adjusting the carrier interval division value of the multiple power units;

[0013] Recalibration module: used to recalibrate the modulation wave parameters and carrier parameters according to the number of remaining power units after bypassing;

[0014] The generating module is used to generate a target driving signal based on the recalibrated modulation wave and carrier parameters to enable the load corresponding to the inverter to operate normally.

[0015] In a third aspect, the present application provides a frequency converter, comprising a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus;

[0016] Memory for storing computer programs;

[0017] The processor is used to implement the automatic bypass method based on the inverter as described in any embodiment of the first aspect when executing the program stored in the memory.

[0018] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the automatic bypass method based on the inverter as described in any embodiment of the first aspect is implemented.

[0019] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0020] If the main control unit receives fault information reported by a power unit, it determines the target bypass strategy based on pre-configured bypass parameters. The target bypass strategy includes an asymmetric bypass strategy and a symmetric bypass strategy. The faulty power unit is bypassed according to the target bypass strategy, and the carrier interval division values ​​of multiple power units are adjusted. The modulation wave parameters and carrier parameters are recalibrated based on the number of remaining power units after bypassing. Based on the recalibrated modulation wave and carrier parameters, the target drive signal is generated to ensure the normal operation of the corresponding load of the inverter. Through real-time fault detection and determination of the bypass strategy, a rapid response can be made when a power unit fault occurs, preventing the fault from escalating. This allows the inverter to operate by cascading different numbers of power units, improving the reliability and stability of the inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 This is a flow chart of an embodiment of the automatic bypass method based on a frequency converter of the present application;

[0024] Figure 2 Schematic diagram of the avoidance mechanism corresponding to the asymmetric bypass strategy in the embodiment of the present application;

[0025] Figure 3 This is a schematic diagram of neutral point offset in an embodiment of the present application;

[0026] Figure 4 Schematic diagram of the avoidance mechanism corresponding to the symmetric bypass strategy in the embodiment of the present application;

[0027] Figure 5 This is a block diagram of the implementation of the frequency converter in the embodiment of the present application;

[0028] Figure 6 This is a module diagram of an embodiment of an automatic bypass device based on a frequency converter of the present application;

[0029] Figure 7 A schematic diagram of an embodiment of a frequency converter of the present application;

[0030] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0032] The disclosure below provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, these are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0033] This application provides an automatic bypass method based on a frequency converter. Figure 1 The figure shows a method flow diagram of an embodiment of the automatic bypass method based on a frequency converter of the present application. The method can be executed by a frequency converter, which includes a main control unit and multiple power units in communication with the main control unit. The frequency converter can be implemented by software and / or hardware. The automatic bypass method based on the frequency converter includes:

[0034] Step S10: If the main control unit receives the fault information reported by the power unit, the main control unit determines a target bypass strategy according to pre-configured bypass parameters, wherein the target bypass strategy includes an asymmetric bypass strategy and a symmetric bypass strategy;

[0035] Step S20: bypassing the faulty power unit according to the target bypass strategy, and adjusting the carrier interval division values ​​of the multiple power units;

[0036] Step S30: recalibrating the modulation wave parameters and the carrier wave parameters according to the number of remaining power units after bypassing;

[0037] Step S40: Based on the recalibrated modulation wave and carrier parameters, a target driving signal is generated to enable the load corresponding to the inverter to operate normally.

[0038] This embodiment uses a cascaded high-voltage inverter as an example. The power unit is the basic functional module in the cascaded high-voltage inverter, responsible for converting and controlling electrical energy. Multiple power units work together to drive the load. The master control unit is responsible for sending drive information to the power units.

[0039] Preconfigured bypass parameters can be sent to the main control unit via the inverter's corresponding host computer before the inverter is operational. These bypass parameters indicate the target bypass strategy to adopt when a power unit fails. These target bypass strategies include asymmetric and symmetric. A symmetric bypass strategy bypasses all power units in the same position across all three phases when a power unit in one phase fails. This strategy maintains symmetry in the three-phase output, preventing voltage imbalances in the three phases caused by changes in the number of units in a single phase.

[0040] The asymmetric bypass strategy only processes the faulty power unit itself and does not affect the power units in the same position in other phases. This strategy can be independently processed according to the actual fault situation of each phase. It should be noted that each power unit failure has a corresponding target bypass strategy, and the target bypass strategy adopted when each power unit fails can also be adjusted according to the actual situation. For example, assuming that there are 9 power units in each phase, the bypass parameters can be configured to adopt an asymmetric bypass strategy when the 5th power unit fails, and a symmetric bypass strategy when the 9th power unit fails.

[0041] Because power units may experience faults such as overheating, overcurrent, and short circuits during operation, they can perform real-time self-fault detection during operation. When a fault is detected, the power unit uploads the fault information to the main control unit's microprocessor via the main control unit's programmable device. After receiving the fault information reported by the power unit, the main control unit determines whether to adopt an asymmetric or symmetric bypass strategy based on pre-configured bypass parameters. Real-time fault detection and bypass strategy determination enable a rapid response to power unit faults, preventing escalation of the fault and improving the inverter's reliability and stability.

[0042] After determining the target bypass strategy, the faulty power unit needs to be bypassed and the carrier interval division values ​​of the remaining power units adjusted accordingly to ensure normal system operation and output performance. For example, assuming an asymmetric bypass strategy is adopted, the main control unit maps the carrier interval division value of the fifth power unit in phase A to the sixth power unit. The drive intervals of the remaining power units in this phase are also adjusted accordingly to ensure stable operation of the inverter.

[0043] Since the number of remaining power cells changes after bypass operation, the modulation wave parameters and carrier parameters need to be recalibrated based on the new number of power cells to ensure balanced and stable output voltage. The modulation wave parameters, such as amplitude, frequency, and phase, can be recalculated based on the number of remaining power cells, as well as the frequency and amplitude of the carrier. For example, in the case of asymmetric bypass, if the number of remaining power cells in each phase is different, the initial phase angles of the three phases need to be recalculated so that the three-phase line voltage output from the high-voltage inverter to the motor remains balanced. The recalibrated modulation wave and carrier frequency can better match the system configuration after bypass, ensuring the normal operation of the load corresponding to the inverter (for example, the motor).

[0044] A new target drive signal is generated based on the recalibrated modulation wave and carrier frequency to control the switching of the power unit and ensure the normal operation of the inverter's corresponding load. The programmable device in the main control unit uses pulse width modulation (PWM) technology based on the recalculated modulation wave and carrier parameters to generate the target drive signal. Once the target drive signal is distributed to each power unit, it controls the on and off of its internal power devices (such as IGBTs), thereby achieving variable frequency speed control of the motor. By generating the target drive signal, the impact of power unit failure on the normal operation of the inverter can be reduced.

[0045] In one embodiment, if the target bypass strategy is an asymmetric bypass strategy, bypassing the faulty power unit according to the target bypass strategy and adjusting the carrier interval division values ​​of the multiple power units include:

[0046] Determining the serial number of the faulty power unit and bypassing the faulty power unit, wherein the serial number of each power unit is pre-assigned;

[0047] Mapping the carrier interval division value of the faulty power unit to the power unit with the next sequence number of the faulty power unit;

[0048] The carrier interval division value of the power unit arranged after the faulty power unit is mapped to the power unit with the next sequence number after the power unit according to the sequence number.

[0049] After the fault information reported by the power unit is sent to the main control unit, the main control unit determines the serial number of the power unit that sent the fault and bypasses the faulty power unit. The faulty power unit refers to the power unit that reported the fault information, that is, the faulty power unit is isolated and its output is stopped. Then, the carrier interval division value of the faulty power unit is mapped to the power unit with the next serial number of the faulty power unit. Figure 2As shown, a schematic diagram of the avoidance mechanism corresponding to the asymmetric bypass strategy in an embodiment of the present application is provided. The principle of the avoidance mechanism is explained with the number of units per phase being 9. When the main control unit receives the fault information reported by the 5th power unit, the main control unit maps the carrier interval division value of the 5th power unit to the next adjacent unit (i.e., the 6th power unit). The carrier interval division values ​​of the power units ordered after the faulty power unit (i.e., the carrier interval division values ​​of the original 6th, 7th, 8th, and 9th power units) are sequentially mapped backward to the power units with the next sequence number of the power unit. For example, the carrier interval division value of the original 6th power unit is mapped to the 7th power unit. By adjusting the carrier interval division value, the remaining power units can be fully utilized while avoiding the faulty unit, maintaining the output capacity and efficiency of the inverter. It can be understood that the sequence number of each power unit is pre-assigned. Similarly, if the power units with sequence numbers 2, 5, and 7 fail, the power units with sequence numbers 2, 5, and 7 will also use the above-mentioned avoidance mechanism to map the carrier interval division value to the next adjacent power unit.

[0050] Furthermore, the recalibration of the modulation wave parameters and the carrier parameters according to the number of the remaining power units after the bypass includes:

[0051] Calculate the initial phase of each phase modulation wave of the inverter based on the number of remaining power units after bypassing;

[0052] Recalibrate the modulation wave according to the initial phase of each phase modulation wave to obtain a recalibrated modulation wave calibration value;

[0053] The carrier frequency is recalibrated according to the recalibrated modulation wave calibration value and the number of the remaining power units after bypassing to obtain a recalibrated carrier frequency.

[0054] After a power unit fails and is bypassed, the number of remaining power units changes. For example, if the fifth power unit in phase A fails and is bypassed, there are now eight remaining power units in phase A, while phases B and C each have nine. To ensure balanced three-phase output voltages, the modulation wave parameters and carrier parameters need to be recalibrated based on the new number of power units. Based on the number of remaining power units after bypassing, the initial phase of the inverter modulation wave for each phase is calculated, and the amplitude and phase of the modulation wave are adjusted to balance the output voltage of phase A with the output voltages of phases B and C. Based on the recalibrated modulation wave parameters and the number of remaining power units, the carrier frequency is adjusted. For example, the carrier frequency can be lowered to reduce switching losses and ensure balanced and stable output voltages.

[0055] Furthermore, the calculation of the initial phase of each phase modulation wave of the inverter according to the number of remaining power units after bypassing includes:

[0056] Determining the offset angle of the phase sequence where the faulty power unit is located;

[0057] Determining an effective value of the equivalent line voltage after the neutral point drift according to the number of the remaining power units;

[0058] The initial phase of each phase modulation wave of the inverter is calculated based on the effective value of the equivalent line voltage and the offset angle.

[0059] Wherein, determining the offset angle of the phase sequence in which the faulty power unit is located includes:

[0060] Determining a voltage neutral point of the frequency converter after the faulty power unit fails;

[0061] Draw a parallel line corresponding to a target segment through the voltage neutral point, wherein the target segment is a segment formed by the voltage neutral point of the inverter before the fault of the faulty power unit and the phase voltage output point corresponding to the phase sequence;

[0062] The offset angle of the phase sequence where the faulty power unit is located is determined according to the parallel lines.

[0063] Ginseng Figure 3 The figure shows the neutral point offset diagram in the embodiment of the present application, wherein Point A is the voltage neutral point of the inverter after the power unit fails, and point A is the voltage output point of phase A. The number of power units operating normally in each phase after the failure is recorded as a1, b1, and c1 respectively. After standardization with the unit output voltage as the base value, the effective values ​​of the phase voltage of each phase are a, b, and c respectively. Figure 3 middle x It is the effective value of the equivalent line voltage after the voltage neutral point drifts (the side length of the equilateral triangle).

[0064] Assume that the initial phase difference of phase A is 0 degrees during normal operation, and the offset angle of bypass phase A is recorded as A1. Do Parallel lines , get the A phase offset angle A1, we can get A1= π / 3-θ , according to the trigonometric function formula, we can get formula (1) and formula (2):

[0065] (1)

[0066] (2)

[0067] θ is the intermediate variable. Expand equation (2) and substitute it into equation (1) to obtain equation (3):

[0068] (3)

[0069] Simplifying formula (3) yields formula (4):

[0070] (4)

[0071] The effective value of the equivalent line voltage can be calculated from equation (4), and then the phase angle of each phase voltage when the power unit fails can be calculated by equations (5) and (6):

[0072] (5)

[0073] (6)

[0074] The phase angles of each phase after the neutral point drift are α , β , then the relationship between the three-phase modulated sine waves after the neutral point shift is shown in formula (7):

[0075] (7)

[0076] Where m is the modulation index, α Indicates the initial phase of the C-phase modulation wave, β Indicates the initial phase of the B-phase modulation wave.

[0077] In one embodiment, if the target bypass strategy is a symmetric bypass strategy, bypassing the faulty power unit according to the target bypass strategy and adjusting the carrier interval division values ​​of the multiple power units include:

[0078] Determining the sequence number of the faulty power unit and the phase sequence of the faulty power unit, wherein the sequence number of each power unit is pre-assigned;

[0079] Bypassing the faulty power unit and the remaining power units with the same phase sequence number;

[0080] The carrier interval division values ​​of the faulty power unit and the power unit with the same sequence number are respectively mapped to the power unit with the next sequence number.

[0081] Ginseng Figure 4As shown, this is a schematic diagram of the avoidance mechanism corresponding to the symmetrical bypass strategy in the embodiment of the present application. The principle of the avoidance mechanism is explained with the number of units per phase being 9. If a power unit in one phase fails, all power units with the same serial number in the three phases will be bypassed, and the carrier interval division values ​​that are not bypassed will be shifted in sequence and then sent down for processing. For example, assuming that power unit 9 of phase A reports fault information, the carrier interval division value of the 9th power unit of phases B and C will be directly eliminated, and the carrier interval division values ​​of the 8 power units will be re-issued respectively. Similarly, if 3 different power units in a phase report fault information, all power units with the same serial number in the three phases will be bypassed, and the carrier interval division value will be shifted in sequence to the next adjacent unit.

[0082] In one embodiment, the method further comprises:

[0083] If the main control unit does not receive the fault information reported by the power unit, it sends driving information generated by comparing the modulation wave with the carrier wave to each power unit respectively, so as to enable the load corresponding to the inverter to operate normally.

[0084] If the main control unit does not receive any fault information from any power unit, it indicates that each power unit in the inverter is operating normally. The main control unit then needs to send drive information generated by comparing the modulation wave with the carrier wave to each power unit according to the preset control strategy to ensure that the inverter can properly drive the corresponding load. The modulation wave is a sinusoidal signal that carries information such as the output voltage amplitude, frequency, and phase. The carrier wave is a high-frequency triangular or sawtooth wave that is compared with the modulation wave to generate a PWM signal. The programmable device in the main control unit compares the modulation wave with the carrier wave to generate the PWM signal. When the amplitude of the modulation wave is greater than that of the carrier wave, a high level is generated; otherwise, a low level is generated. The PWM signal is used to control the switching operation of the power unit. The main control unit sends the generated PWM signal as drive information to each power unit. Each power unit controls the on and off of its internal power devices (such as IGBTs) based on the received drive information, thereby achieving variable frequency speed control of the motor.

[0085] Ginseng Figure 5 As shown, this is the implementation block diagram of the frequency converter in the embodiment of the present application. If no power unit fault occurs in each phase, the microprocessor in the main control unit sends down the three-phase modulation wave information according to the required number of units, compares it with the carrier wave to generate the driving information of each unit, and drives the sending unit at a fixed time interval.

[0086] If a power unit uploads fault information, the main control unit recalibrates the three-phase modulated wave data and, based on either a symmetrical or asymmetrical bypass strategy, avoids the drive range for each phase power unit. The data is then sent to the programmable device for processing before being sent to the corresponding power unit for wave analysis. The target drive signal for each phase power unit is equivalent to the calibration value compared between the three-phase modulated wave and the carrier wave of each phase.

[0087] Reference Figure 6 , which is a functional module diagram of the automatic bypass device 100 based on the frequency converter of the present application.

[0088] The inverter-based automatic bypass device 100 described herein can be installed in an inverter. Depending on the functionality implemented, the inverter-based automatic bypass device 100 may include a determination module 110, a bypass module 120, a recalibration module 130, and a generation module 140. A module, also referred to herein as a unit, refers to a series of computer program segments that can be executed by an inverter processor and perform a fixed function, and are stored in the inverter's memory.

[0089] In this embodiment, the functions of each module / unit are as follows:

[0090] Determining module 110: configured to determine a target bypass strategy based on pre-configured bypass parameters upon receiving fault information reported by a power unit, wherein the target bypass strategy includes an asymmetric bypass strategy and a symmetric bypass strategy;

[0091] Bypass module 120: configured to bypass the faulty power unit according to the target bypass strategy and adjust the carrier interval division values ​​of the multiple power units;

[0092] Recalibration module 130: used to recalibrate modulation wave parameters and carrier parameters according to the number of remaining power units after bypassing;

[0093] The generating module 140 is configured to generate a target driving signal based on the recalibrated modulation wave and carrier parameters to enable the load corresponding to the inverter to operate normally.

[0094] In one embodiment, if the target bypass strategy is an asymmetric bypass strategy, bypassing the faulty power unit according to the target bypass strategy and adjusting the carrier interval division values ​​of the multiple power units include:

[0095] Determining the serial number of the faulty power unit and bypassing the faulty power unit, wherein the serial number of each power unit is pre-assigned;

[0096] Mapping the carrier interval division value of the faulty power unit to the power unit with the next sequence number of the faulty power unit;

[0097] The carrier interval division value of the power unit arranged after the faulty power unit is mapped to the power unit with the next sequence number after the power unit according to the sequence number.

[0098] In one embodiment, recalibrating the modulation wave parameters and the carrier parameters according to the number of remaining power units after bypassing includes:

[0099] Calculate the initial phase of each phase modulation wave of the inverter based on the number of remaining power units after bypassing;

[0100] Recalibrate the modulation wave according to the initial phase of each phase modulation wave to obtain a recalibrated modulation wave calibration value;

[0101] The carrier frequency is recalibrated according to the recalibrated modulation wave calibration value and the number of the remaining power units after bypassing to obtain a recalibrated carrier frequency.

[0102] In one embodiment, the step of calculating the initial phase of each phase modulation wave of the inverter according to the number of remaining power units after bypassing includes:

[0103] Determining the offset angle of the phase sequence where the faulty power unit is located;

[0104] Determining an effective value of the equivalent line voltage after the neutral point drift according to the number of the remaining power units;

[0105] The initial phase of each phase modulation wave of the inverter is calculated based on the effective value of the equivalent line voltage and the offset angle.

[0106] In one embodiment, determining the offset angle of the phase sequence of the faulty power unit includes:

[0107] Determining a voltage neutral point of the frequency converter after the faulty power unit fails;

[0108] Draw a parallel line corresponding to a target segment through the voltage neutral point, wherein the target segment is a segment formed by the voltage neutral point of the inverter before the fault of the faulty power unit and the phase voltage output point corresponding to the phase sequence;

[0109] The offset angle of the phase sequence where the faulty power unit is located is determined according to the parallel lines.

[0110] In one embodiment, if the target bypass strategy is a symmetric bypass strategy, bypassing the faulty power unit according to the target bypass strategy and adjusting the carrier interval division values ​​of the multiple power units include:

[0111] determining a sequence number of the faulty power unit and a phase sequence in which the faulty power unit is located, wherein the sequence number of each power unit is pre-allocated;

[0112] bypassing the faulty power unit and the power unit with the same sequence number as the faulty power unit;

[0113] mapping carrier interval division values of the faulty power unit and the power unit with the same sequence number to the power unit with the next sequence number.

[0114] In one embodiment, the method further comprises:

[0115] if the master unit does not receive the fault information reported by the power unit, respectively issuing driving information generated by comparing the modulation wave and the carrier to each power unit, so that the corresponding load of the frequency converter is normally operated.

[0116] Referring to Figure 7 , which is a schematic diagram of a preferred embodiment of the frequency converter.

[0117] The frequency converter comprises a processor 111, a communication interface 112, a memory 113 and a communication bus 114, wherein the processor 111, the communication interface 112 and the memory 113 complete mutual communication through the communication bus 114;

[0118] Figure 7 Only the frequency converter with components 111, 112, 113 and 114 is shown, but it should be understood that it is not required to implement all the shown components, and more or fewer components can be alternatively implemented.

[0119] In one embodiment of the present application, the processor 111 is configured to execute the program stored in the memory 113 to implement the automatic bypass method based on the frequency converter provided by any one of the preceding method embodiments, comprising:

[0120] if the master unit receives the fault information reported by the power unit, the master unit determines a target bypass strategy according to pre-configured bypass parameters, wherein the target bypass strategy comprises an asymmetric bypass strategy and a symmetric bypass strategy;

[0121] bypassing the faulty power unit according to the target bypass strategy and adjusting the carrier interval division values of the plurality of power units;

[0122] re-calibrating the modulation wave parameters and the carrier parameters according to the number of the remaining power units after bypassing;

[0123] generating a target driving signal based on the re-calibrated modulation wave and carrier parameters to make the corresponding load of the frequency converter normally operate.

[0124] For a detailed description of the above steps, please refer to the Figure 1 Description of a flowchart of an embodiment of an automatic bypass method based on a frequency converter.

[0125] In addition, embodiments of the present application further provide a computer-readable storage medium, which may be non-volatile or volatile. The computer-readable storage medium includes a data storage area and a program storage area. The program storage area stores an inverter-based automatic bypass program. When the inverter-based automatic bypass program is executed by a processor, the following operations are implemented:

[0126] If the main control unit receives fault information reported by the power unit, the main control unit determines a target bypass strategy according to pre-configured bypass parameters, wherein the target bypass strategy includes an asymmetric bypass strategy and a symmetric bypass strategy;

[0127] Bypassing the faulty power unit according to the target bypass strategy, and adjusting the carrier interval division values ​​of the multiple power units;

[0128] Recalibrate the modulation wave parameters and carrier parameters according to the number of remaining power units after bypassing;

[0129] Based on the recalibrated modulation wave and carrier parameters, a target driving signal is generated to enable the load corresponding to the inverter to operate normally.

[0130] The specific implementation of the computer-readable storage medium of the present application is roughly the same as the specific implementation of the automatic bypass method based on the above-mentioned inverter, and will not be repeated here.

[0131] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0132] Through the description of the above embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a general hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the relevant technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0133] It should be noted that the terms "first", "second", and the like, used in the description and in the claims of this application are only used for distinguishing between similar elements and do not necessarily have an ordinal or chronological significance. By definition, the term "a" or "an" or the like does not exclude a plurality, and the term "multiple" or "plurality" or the like does not exclude a singular. Thus, for example, the term "a" or "an" or the like used in the description or the claims does not exclude a plurality and the term "plurality" or "a plurality" does not exclude a singular. Furthermore, the features of the different embodiments can be combined with each other, unless specifically mentioned otherwise. The conjunction "or" used in the description and in the claims of the present application is both inclusive and exclusive, unless otherwise indicated. That is, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), or A is false (or not present) and B is true (or present). Also, the term "comprising", used in the description and in the claims of the present application, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus meant to cover "optional" elements or steps not specifically recited. Similarly, the term "comprising" should not be interpreted as implying that the apparatus or method has to comprise all of the features mentioned in this specification, or that the method or apparatus has to operate exactly as described in this specification. The term "consisting essentially of should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus meant to cover "optional" elements or steps not specifically recited. Similarly, the term "consisting essentially of should not be interpreted as implying that the apparatus or method has to consist of all of the features mentioned in this specification, or that the method or apparatus has to operate exactly as described in this specification.

[0134] It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described unless specifically identified as an order dependent step. It is also to be understood that additional or alternative steps can be employed.

[0135] The above description is merely that of certain embodiments of the application and various modifications can be made without departing from the spirit and scope of the application. Therefore, the above description should not be taken as limiting the scope of the application but merely as describing many embodiments of it.

Claims

1. An automatic bypass method based on a frequency converter, characterized in that: The frequency converter includes a main control unit and a plurality of power units communicatively connected to the main control unit, and the method includes: If the main control unit receives fault information reported by the power unit, the main control unit determines a target bypass strategy based on pre-configured bypass parameters, wherein the target bypass strategy includes an asymmetric bypass strategy and a symmetric bypass strategy. The bypass parameters are sent to the main control unit by the host computer corresponding to the inverter before the inverter is operated. The bypass parameters are used to indicate which target bypass strategy to adopt when a power unit fails; Bypassing the faulty power unit according to the target bypass strategy, and adjusting the carrier interval division values ​​of the multiple power units; Recalibrate the modulation wave parameters and carrier parameters according to the number of remaining power units after bypassing; Based on the recalibrated modulation wave and carrier parameters, a target drive signal is generated to enable the load corresponding to the inverter to operate normally; If the target bypass strategy is an asymmetric bypass strategy, bypassing the faulty power unit according to the target bypass strategy and adjusting the carrier interval division values ​​of the multiple power units include: Determining the serial number of the faulty power unit and bypassing the faulty power unit, wherein the serial number of each power unit is pre-assigned; Mapping the carrier interval division value of the faulty power unit to the power unit with the next sequence number of the faulty power unit; The carrier interval division value of the power unit arranged after the faulty power unit is mapped to the power unit with the next sequence number after the power unit according to the sequence number.

2. The automatic bypass method based on a frequency converter according to claim 1, characterized in that: The recalibration of the modulation wave parameters and the carrier parameters according to the number of the remaining power units after the bypass includes: Calculate the initial phase of each phase modulation wave of the inverter based on the number of remaining power units after bypassing; Recalibrate the modulation wave according to the initial phase of each phase modulation wave to obtain a recalibrated modulation wave calibration value; The carrier frequency is recalibrated according to the recalibrated modulation wave calibration value and the number of the remaining power units after bypassing to obtain a recalibrated carrier frequency.

3. The automatic bypass method based on a frequency converter according to claim 2, characterized in that: The step of calculating the initial phase of each phase modulation wave of the inverter according to the number of remaining power units after bypassing includes: Determining the offset angle of the phase sequence where the faulty power unit is located; Determining an effective value of the equivalent line voltage after the neutral point drift according to the number of the remaining power units; The initial phase of each phase modulation wave of the inverter is calculated based on the effective value of the equivalent line voltage and the offset angle.

4. The automatic bypass method based on a frequency converter according to claim 3, characterized in that: Determining the offset angle of the phase sequence where the faulty power unit is located includes: Determining a voltage neutral point of the frequency converter after the faulty power unit fails; Draw a parallel line corresponding to a target segment through the voltage neutral point, wherein the target segment is a segment formed by the voltage neutral point of the inverter before the fault of the faulty power unit and the phase voltage output point corresponding to the phase sequence; The offset angle of the phase sequence where the faulty power unit is located is determined according to the parallel lines.

5. The automatic bypass method based on a frequency converter according to claim 1, characterized in that: If the target bypass strategy is a symmetrical bypass strategy, bypassing the faulty power unit according to the target bypass strategy and adjusting the carrier interval division values ​​of the multiple power units include: Determining the sequence number of the faulty power unit and the phase sequence of the faulty power unit, wherein the sequence number of each power unit is pre-assigned; Bypassing the faulty power unit and the remaining power units with the same phase sequence number; The carrier interval division values ​​of the faulty power unit and the power unit with the same sequence number are respectively mapped to the power unit with the next sequence number.

6. The automatic bypass method based on a frequency converter according to claim 1, characterized in that: The method further comprises: If the main control unit does not receive the fault information reported by the power unit, it sends driving information generated by comparing the modulation wave with the carrier wave to each power unit respectively, so as to enable the load corresponding to the inverter to operate normally.

7. An automatic bypass device based on a frequency converter, characterized in that: The device comprises: Determination module: used to determine the target bypass strategy based on pre-configured bypass parameters upon receiving fault information reported by the power unit, wherein the target bypass strategy includes an asymmetric bypass strategy and a symmetric bypass strategy. The bypass parameters are sent to the main control unit by the host computer corresponding to the inverter before the inverter is operated. The bypass parameters are used to indicate which target bypass strategy to adopt when a power unit fault occurs; Bypass module: used to bypass the faulty power unit according to the target bypass strategy and adjust the carrier interval division value of multiple power units; Recalibration module: used to recalibrate the modulation wave parameters and carrier parameters according to the number of remaining power units after bypassing; A generating module is used to generate a target driving signal based on the recalibrated modulation wave and carrier parameters to enable the load corresponding to the inverter to operate normally; If the target bypass strategy is an asymmetric bypass strategy, bypassing the faulty power unit according to the target bypass strategy and adjusting the carrier interval division values ​​of the multiple power units include: Determining the serial number of the faulty power unit and bypassing the faulty power unit, wherein the serial number of each power unit is pre-assigned; Mapping the carrier interval division value of the faulty power unit to the power unit with the next sequence number of the faulty power unit; The carrier interval division value of the power unit arranged after the faulty power unit is mapped to the power unit with the next sequence number after the power unit according to the sequence number.

8. A frequency converter, characterized in that: It includes a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; Memory for storing computer programs; The processor is configured to implement the automatic bypass method based on the frequency converter according to any one of claims 1 to 6 when executing the program stored in the memory.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the automatic bypass method based on a frequency converter according to any one of claims 1 to 6 is implemented.

Images