A control device, method and frequency converter for the main control board of a frequency converter

Abstract

The present invention discloses a control device, a control method and an inverter for a main control board of an inverter. The device includes: a control unit for sending PWM signals; a driving unit for outputting driving signals according to the PWM signals, the number of paths of the driving signals being the same as the number of paths of the PWM signals; the control unit further issues a selection signal; a detection unit for selecting, according to the selection signal, one driving signal from the n driving signals corresponding to the n PWM signals as a detection signal; the control unit further determines whether a driving fault occurs in the inverter based on one or more detection signals, so as to start a preset protection mechanism when a driving fault occurs in the inverter. With this solution, by detecting the driving signals of a series of driving circuits in the main control board of the inverter, the fault location can be accurately located and protected when an IGBT module driving fault occurs in the inverter, which is beneficial to improving the working reliability of the inverter.

Description

Technical Field

[0001] The present invention belongs to the technical field of frequency converters, and particularly relates to a control device, a control method and a frequency converter for a main control board of a frequency converter, and more particularly to a driving signal detection device, a detection method and a frequency converter for a main control board of a frequency converter. Background Art

[0002] In the product application of frequency converters, the driving signal of an IGBT (Insulated Gate Bipolar Transistor) is led out from a DSP (Digital Signal Processing) chip in the main control board of the frequency converter, and is amplified and interlocked through a series of driving circuits and then sent to the IGBT driving board. Among them, when a driving fault of the IGBT module occurs in the frequency converter, the fault location cannot be accurately located and protected in time, which affects the working reliability of the frequency converter.

[0003] The above content is only used to assist in understanding the technical solution of the present invention, and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The object of the present invention is to provide a control device, a control method and a frequency converter for a main control board of a frequency converter, so as to solve the problem that when a driving fault of the IGBT module occurs in the frequency converter, the fault location cannot be accurately located and protected in time, which affects the working reliability of the frequency converter, and achieve the effect of accurately locating the fault location and protecting when a driving fault of the IGBT module occurs in the frequency converter by detecting the driving signals of a series of driving circuits in the main control board of the frequency converter, which is beneficial to improving the working reliability of the frequency converter.

[0005] In a control device of a main control board of an inverter provided by the present invention, the main control board of the inverter includes: a driving unit and a control unit; the number of the driving units is n, and n is a positive integer; the control device of the main control board of the inverter includes: a detection unit; wherein, the control unit is configured to send a PWM signal, and the number of paths of the PWM signal is n; the driving unit is configured to output a driving signal according to the PWM signal; the number of paths of the driving signal is the same as the number of paths of the PWM signal; the control unit is further configured to issue a selection signal; the selection signal is a signal for selecting one driving signal from n driving signals corresponding to n paths of the PWM signals; the detection unit is configured to select one driving signal from n driving signals corresponding to n paths of the PWM signals as a detection signal according to the selection signal; the control unit is further configured to determine whether the inverter has a driving fault based on one or more of the detection signals among n driving signals corresponding to n paths of the PWM signals, so as to activate a preset protection mechanism when the inverter has a driving fault; wherein, one or more of the detection signals include: the selected one detection signal.

[0006] In some embodiments, the detection unit includes: a signal feedback module and a selection module; wherein, the detection unit selects one driving signal from n driving signals corresponding to n paths of the PWM signals according to the selection signal, including: the number of the signal feedback modules is n paths, and each of the n signal feedback modules is configured to compare the parameters of one driving signal with a set parameter range for one driving signal among n driving signals corresponding to n paths of the PWM signals to obtain a comparison result as one feedback signal; the n comparison results that can be obtained by the n signal feedback modules are used as the n feedback signals of the n driving signals; the selection module is configured to select one feedback signal from the feedback signals of the n driving signals as one detection signal according to the selection signal.

[0007] In some embodiments, one signal feedback module includes: a comparator module; wherein, the inverting input terminal of the comparator module can input the set parameter range; the non-inverting input terminal of the comparator module can input one driving signal; the output terminal of the comparator module can output one feedback signal.

[0008] In some embodiments, the drive unit includes a voltage conversion module, a bridge arm signal interlock module, and an output locking module. Among them, the drive unit outputs a drive signal according to the PWM signal, including: the voltage conversion module is configured to convert the voltage of the PWM signal to obtain a signal with a set voltage; the bridge arm signal interlock module is configured to perform an interlock process on the upper and lower bridge arms of the IGBT drive board of the frequency converter based on the signal with the set voltage, and then output the drive signal; the output locking module is configured to lock the drive signal before the frequency converter works to prohibit the IGBT drive board of the frequency converter from starting based on the drive signal.

[0009] In some embodiments, the output locking module includes an AND logic module. Among them, the AND logic module is configured to perform an AND operation on the drive signal and the PWM signal to obtain an operation result, so as to lock the output of the drive signal according to the operation result. Among them, the drive signal includes at least one of an upper bridge arm drive signal and a lower bridge arm drive signal.

[0010] In some embodiments, the control unit is further configured to, when the drive unit includes an output locking module, before the frequency converter works, make the output locking module prohibit the output of the drive signal, and after outputting a PWM signal with a set frequency and / or a set duty cycle, determine whether the frequency converter has a drive fault based on one or more of the detection signals in the n drive signals corresponding to the n PWM signals, so as to make the output locking module allow the drive signal only when the frequency converter does not have a drive fault, to control the frequency converter to drive and work; and, after the frequency converter works, determine whether the frequency converter has a drive fault based on one or more of the detection signals in the n drive signals corresponding to the n PWM signals.

[0011] In some embodiments, the control unit determines whether a drive fault occurs in the frequency converter based on one or more of the detection signals corresponding to the n PWM signals among the n drive signals, including: for one or more of the detection signals among the n drive signals, using the capture module of the control unit to capture one or more of the detection signals among the n drive signals; if the capture module can capture one or more of the detection signals, it is determined that one or more of the drive units corresponding to one or more of the detection signals among the n drive units of the frequency converter do not have a drive fault, and the control of the frequency converter continues to work; if the capture module cannot capture one or more of the detection signals, it is determined that one or more of the drive units corresponding to one or more of the detection signals among the n drive units of the frequency converter have a drive fault, and the position where the drive fault occurs in the frequency converter is determined.

[0012] In some embodiments, the control unit determines the position where the drive fault occurs in the frequency converter, including: determining whether a signal with a set voltage level is captured; if the signal with the set voltage level is captured, it is determined that at least some of the drive units among the n drive units have a fault; if the signal with the set voltage level is not captured, a self-check signal is initiated to detect whether a fault occurs in the detection unit according to the self-check signal.

[0013] In some embodiments, the control unit detects whether a fault occurs in the detection unit according to the detection signal, including: sending the self-check signal to the detection unit and determining whether the capture module of the control unit captures the self-check signal; in the case where the detection unit includes a signal feedback module and a selection module, if the capture module captures the self-check signal, it is determined that the signal feedback module has a fault; if the capture module does not capture the self-check signal, it is determined that the selection module has a fault.

[0014] Matched with the above device, on the other hand, the present invention provides a frequency converter, including: the control device of the main control board of the above-mentioned frequency converter.

[0015] Matched with the above frequency converter, on the other hand, the present invention provides a control method for the main control board of a frequency converter. The main control board of the frequency converter includes: a driving unit and a control unit; the number of the driving units is n, and n is a positive integer; the control method for the main control board of the frequency converter includes: sending a PWM signal through the control unit, and the number of paths of the PWM signal is n; outputting a driving signal through the driving unit according to the PWM signal; the number of paths of the driving signal is the same as the number of paths of the PWM signal; sending a selection signal through the control unit; the selection signal is a signal for selecting one of the n driving signals corresponding to the n PWM signals; through a detection unit, selecting one of the n driving signals corresponding to the n PWM signals as a detection signal according to the selection signal; sending, through the control unit, determining whether the frequency converter has a driving fault based on one or more of the detection signals among the n driving signals corresponding to the n PWM signals, so as to start a preset protection mechanism when the frequency converter has a driving fault; wherein, one or more of the detection signals include: the selected one detection signal.

[0016] In some embodiments, the detection unit includes: a signal feedback module and a selection module; wherein, selecting one of the n driving signals corresponding to the n PWM signals as a detection signal through the detection unit according to the selection signal includes: the number of the signal feedback modules is n, and through each of the n signal feedback modules, for one of the n driving signals corresponding to the n PWM signals, comparing the parameters of one driving signal with a set parameter range to obtain a comparison result as one feedback signal; the n comparison results that can be obtained by the n signal feedback modules are used as the n feedback signals of the n driving signals; through the selection module, selecting one of the feedback signals of the n driving signals as one detection signal according to the selection signal.

[0017] In some embodiments, the driving unit includes: a voltage conversion module, a bridge arm signal interlocking module, and an output locking module; wherein, outputting a driving signal through the driving unit according to the PWM signal includes: converting the voltage of the PWM signal through the voltage conversion module to obtain a signal with a set voltage; performing an interlocking process on the upper and lower bridge arms of the IGBT drive board of the frequency converter based on the signal with the set voltage through the bridge arm signal interlocking module, and then outputting the driving signal; locking the driving signal before the frequency converter works through the output locking module to prohibit the IGBT drive board of the frequency converter from starting based on the driving signal.

[0018] In some embodiments, it further includes: the control unit is further configured to, when the driving unit includes an output locking module, before the frequency converter operates, cause the output locking module to prohibit the output of the driving signal, and after outputting a PWM signal with a set frequency and / or a set duty ratio, determine whether the frequency converter has a driving fault based on one or more of the detection signals in the n driving signals corresponding to the n PWM signals, so as to, when the frequency converter does not have a driving fault, cause the output locking module to allow the driving signal to control the driving and operation of the frequency converter; and, after the frequency converter operates, determine whether the frequency converter has a driving fault based on one or more of the detection signals in the n driving signals corresponding to the n PWM signals.

[0019] In some embodiments, determining whether the frequency converter has a driving fault by the control unit based on one or more of the detection signals in the n driving signals corresponding to the n PWM signals includes: for one or more of the detection signals in the n driving signals, using the capture module of the control unit to capture one or more of the detection signals in the n driving signals; if the capture module can capture one or more of the detection signals, it is determined that one or more of the driving units corresponding to one or more of the detection signals in the n driving units of the frequency converter do not have a driving fault, and the operation of the frequency converter is continued; if the capture module cannot capture one or more of the detection signals, it is determined that one or more of the driving units corresponding to one or more of the detection signals in the n driving units of the frequency converter have a driving fault, and the position where the frequency converter has a driving fault is determined.

[0020] In some embodiments, determining the position where the frequency converter has a driving fault by the control unit includes: determining whether a signal with a set voltage level is captured; if the signal with the set voltage level is captured, it is determined that at least some of the driving units in the n driving units have a fault; if the signal with the set voltage level is not captured, a self-check signal is initiated to detect whether the detection unit has a fault according to the self-check signal.

[0021] In some embodiments, the control unit detects whether the detection unit fails according to the detection signal, including: sending the self-check signal to the detection unit and determining whether the capture module of the control unit captures the self-check signal; in the case where the detection unit includes a signal feedback module and a selection module, if the capture module captures the self-check signal, it is determined that the signal feedback module fails; if the capture module does not capture the self-check signal, it is determined that the selection module fails.

[0022] Thus, in the solution of the present invention, for a series of drive circuits in the control board of the frequency converter, a detection circuit is arranged between the series of drive circuits and the DSP chip. Through this detection circuit, the drive signals of the series of drive circuits in the main control board of the frequency converter are detected, so that when an IGBT module drive fault occurs in the frequency converter, it can be accurately located whether the fault is in the drive circuit of the main control board or in the drive board of the IGBT; thus, by detecting the drive signals of the series of drive circuits in the main control board of the frequency converter, the fault location can be accurately located and protected when an IGBT module drive fault occurs in the frequency converter, which is beneficial to improving the working reliability of the frequency converter.

[0023] Other features and advantages of the present invention will be described in the following specification, and part of them will become obvious from the specification or will be understood by implementing the present invention.

[0024] The technical solutions of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0025] Figure 1 It is a schematic structural diagram of an embodiment of the control device of the main control board of the frequency converter of the present invention;

[0026] Figure 2 It is a schematic structural diagram of an embodiment of the drive signal detection topology;

[0027] Figure 3 It is a schematic structural diagram of an embodiment of the signal feedback circuit;

[0028] Figure 4 It is a schematic diagram of the signal flow direction of an embodiment of the control board drive circuit;

[0029] Figure 5 It is a schematic structural diagram of an embodiment of the output locking circuit;

[0030] Figure 6 It is a schematic flowchart of an embodiment of the signal detection program;

[0031] Figure 7Schematic flowchart of an embodiment of the control method for the main control board of the frequency converter according to the present invention;

[0032] Figure 8 Schematic flowchart of an embodiment of selecting one of the drive signals in the method according to the present invention;

[0033] Figure 9 Schematic flowchart of an embodiment of outputting a drive signal in the method according to the present invention;

[0034] Figure 10 Schematic flowchart of an embodiment of determining whether a drive fault occurs in the frequency converter in the method according to the present invention;

[0035] Figure 11 Schematic flowchart of an embodiment of determining the location where a drive fault occurs in the frequency converter in the method according to the present invention;

[0036] Figure 12 Schematic flowchart of an embodiment of detecting whether a fault occurs in the detection unit in the method according to the present invention;

[0037] Figure 13 Schematic structural diagram of an embodiment of the bridge arm signal interlock shaping circuit;

[0038] Figure 14 Schematic structural diagram of another embodiment of the drive signal detection topology. Detailed implementation manners

[0039] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0040] In the main control board of the frequency converter, it is difficult to ensure that a series of drive circuits always remain in good condition during production or operation of the control board (i.e., the main control board); when a fault occurs in a certain circuit of a series of drive circuits, it is difficult to locate the fault position and protect the frequency converter in a timely manner; when a series of drive circuits are interfered by other signals or the components of a series of drive circuits are abnormal, the frequency and duty cycle of the drive signal are abnormal, and it is difficult for the control board to detect and know such problems. In the case of a fault in the detection circuit of the IGBT drive signal, it is difficult to distinguish whether it is a fault in a series of drive circuits or a fault in the detection circuit of the IGBT drive signal, and false alarms of IGBT drive faults are likely to occur. Before the frequency converter officially operates, it is difficult to know the fault status of a series of drive circuits in the main control board. If the frequency converter starts under the condition of a series of drive circuit faults in the main control board, the probability of accidents occurring in the frequency converter increases.

[0041] According to an embodiment of the present invention, a control device for the main control board of a frequency converter is provided. Refer to Figure 1 the structural schematic diagram of an embodiment of the device of the present invention shown. The main control board of the frequency converter includes: a drive unit and a control unit. The number of the drive units is n, and n is a positive integer. The drive unit, such as a drive circuit, may specifically be a control board drive circuit. The control unit, such as a DSP chip. The control device for the main control board of the frequency converter includes: a detection unit. The detection unit is arranged between the drive unit and the control unit. The detection unit, such as a detection circuit.

[0042] Among them, the control unit is configured to send a PWM signal, and the number of paths of the PWM signal is n.

[0043] The drive unit is configured to output a drive signal according to the PWM signal. The number of paths of the drive signal is the same as the number of paths of the PWM signal. Corresponding to the number of paths of the PWM signal, the number of paths of the drive signal is also n.

[0044] The control unit is further configured to issue a selection signal. The selection signal is a signal for selecting one of the n drive signals corresponding to the n PWM signals.

[0045] The detection unit is configured to select one of the n drive signals corresponding to the n PWM signals as a detection signal according to the selection signal.

[0046] The control unit is further configured to determine whether a drive fault occurs in the frequency converter based on one or more of the detection signals among the n drive signals corresponding to the n PWM signals, so as to start a preset protection mechanism, such as power-off or shutdown protection, when a drive fault occurs in the frequency converter. One or more of the detection signals include: one selected detection signal. That is to say, in one judgment, it is determined whether a drive fault occurs in the frequency converter according to the selected one drive signal.

[0047] In order to accurately locate whether the drive circuit of the main control board or the drive board of the IGBT fails when a drive fault occurs in the IGBT module of the frequency converter. The solution of the present invention provides a method for detecting drive signals on the main control board, which greatly shortens the troubleshooting difficulty and time for technicians. In addition, the state of the drive signal can be clearly understood, and then the interference situation of the drive circuit of the main control board or the operation quality of the drive device can be judged. A self-check method for the signal detection circuit is also provided, reducing the situation of false alarms of drive faults.

[0048] Specifically, the solution of the present invention provides a method for detecting drive signals of the main control board of a frequency converter. A multiplexer is used to feedback the signals of each drive circuit in a series of drive circuits back to the CAP (capture) module of the DSP chip. The level change of the feedback drive signal is captured to detect the conduction condition, signal frequency and duty cycle of each drive circuit.

[0049] In this way, aiming at the problem that it is difficult to ensure that a series of drive circuits always maintain a good state during production or operation of the control board (i.e., the main control board), the drive signal is feedback to the DSP chip for signal level change judgment, so as to obtain the specific state of the drive signal and the conduction condition of the drive circuit, and the conduction condition of a series of drive circuits on the drive signal can be detected in real time.

[0050] In some embodiments, the detection unit includes: a signal feedback module and a selection module. The signal feedback module, such as a 12-way three-phase drive signal feedback circuit. The selection module, such as a 16-way selector.

[0051] Wherein, the detection unit selects one drive signal from the n drive signals corresponding to the n PWM signals according to the selection signal, including:

[0052] The number of the signal feedback modules is n. Each of the n signal feedback modules is configured to compare the parameters of one of the n drive signals corresponding to the n PWM signals with a set parameter range to obtain a comparison result as a feedback signal. The n signal feedback modules can obtain n comparison results as the n feedback signals of the n drive signals.

[0053] The selection module is configured to select one of the feedback signals from the feedback signals of the n drive signals according to the selection signal as a detection signal.

[0054] The solution of the present invention is used for detecting drive signals on the main control board of a high-power frequency converter. To enable those skilled in the art to more clearly understand the embodiments of the present invention, the following combines specific operations and refers to Figures 2 to 6 the example shown to clearly and completely describe the technical solutions in the embodiments of the present invention by way of example.

[0055] The following gives an exemplary description of the voltage conversion of the drive signals on the main control board of the frequency converter.

[0056] Figure 2 It is a schematic structural diagram of an embodiment of a drive signal detection topology. As Figure 2 shown, the drive signal detection topology includes: a signal drive circuit, a drive signal feedback circuit, a signal selection circuit, and a DSP chip control circuit. Among them, the signal drive circuit is, for example, a control board drive circuit. The drive signal feedback circuit is, for example, a 12-channel three-phase drive signal feedback circuit. The signal selection circuit is, for example, a 16-channel selector. The DSP chip control circuit is, for example, a DSP chip. That is to say, specifically, the drive signal detection topology includes: a control board drive circuit (i.e., the drive circuit of the control board), a 12-channel three-phase drive signal feedback circuit, a 16-channel selector, and a DSP chip. The control circuit drive board, the 12-channel three-phase drive signal feedback circuit, the 16-channel selector, and the DSP chip are connected in sequence. The 12-channel three-phase drive signal feedback circuit and the 16-channel selector constitute the detection circuit of the control board drive circuit. The DSP chip sends a selection signal and a detection circuit self-check signal to the 16-channel selector, and the DS chip sends a PWM signal and an output lock signal to the control board drive circuit.

[0057] In related solutions, the signal feedback detection circuit only detects the fault conditions of the drive circuit, and the probability of the feedback detection circuit having a fault is relatively high, and false alarms of faults are likely to occur. The solution of the present invention adds a detection circuit self-check signal to the 16-channel selector circuit to avoid false alarms of drive circuit faults when the feedback fails.

[0058] In some embodiments, one of the signal feedback modules includes: a comparator module, such as a signal feedback circuit mainly composed of a comparator and resistors.

[0059] Among them, the inverting input terminal of the comparator module can input the set parameter range. The non-inverting input terminal of the comparator module can input one of the drive signals. The output terminal of the comparator module can output one of the feedback signals.

[0060] Figure 3 It is a schematic structural diagram of an embodiment of the signal feedback circuit. Refer to Figure 3 In the example shown, the signal feedback circuit is mainly composed of a comparator (such as a comparator of model LM293) and resistors (such as resistor R1, resistor R2, and resistor R3) to form a signal feedback circuit with strong interference. If the drive signal is higher than the upper threshold voltage of 3.18V, the comparator outputs a high-level signal. If the drive signal is lower than the lower threshold voltage of 2.7V, the comparator outputs a low-level signal.

[0061] Among them, an analog signal with a voltage level may have interference fluctuations during circuit transmission. For example, a high-level signal of 3.3V may suddenly appear as 3V or 3.1V, etc. during transmission fluctuations. If the high level is slightly lower than 3.3V at this time and the comparator outputs a low level, it is incorrect. Therefore, when the output of the comparator is in the state of changing from high level to low level, the input comparison value needs to be lower than the lower threshold voltage of 2.7V to output a low level. Similarly, if the low level fluctuates instantaneously around 2.7V and is considered a high level, it is incorrect. Therefore, when the output of the comparator is in the state of changing from low level to high level, the input comparison value needs to be higher than the upper threshold voltage of 3.18V to output a high level. This can avoid the comparator output level from switching erroneously due to short-term small fluctuations in the level voltage, which is to improve the anti-interference ability.

[0062] Figure 3 The example shown is an example of a drive signal feedback circuit. Compared with the feedback circuit using an optocoupler module in the related solutions. The solution of the present invention uses a comparator and corresponding resistors to form a signal feedback circuit with strong anti-interference ability, and is connected to a selector circuit to form an overall detection circuit.

[0063] In some embodiments, the drive unit includes: a voltage conversion module, a bridge arm signal interlock module, and an output locking module. The voltage conversion module, the bridge arm signal interlock module, and the output locking module are sequentially arranged between the control unit such as a DSP chip and the IGBT drive board of the frequency converter. The voltage conversion module, such as a voltage conversion circuit. The bridge arm signal interlock module, such as a bridge arm signal interlock shaping circuit. The output locking module, such as an output locking circuit.

[0064] Among them, the driving unit outputs a driving signal according to the PWM signal, including:

[0065] The voltage conversion module is configured to convert the voltage of the PWM signal to obtain a signal with a set voltage.

[0066] The bridge arm signal interlocking module is configured to perform interlocking processing on the upper and lower bridge arms of the IGBT drive board of the frequency converter based on the signal with the set voltage, and then output the driving signal.

[0067] The output locking module is configured to lock the driving signal before the frequency converter works to prohibit the IGBT drive board of the frequency converter from starting based on the driving signal.

[0068] Figure 4 It is a schematic diagram of the signal flow direction of an embodiment of the control board drive circuit. As Figure 4 shown, the control board drive circuit includes: a DSP chip, a voltage conversion circuit, a bridge arm signal interlocking and shaping circuit, an output locking circuit, and an IGBT drive board connected in sequence. Among them, the voltage conversion circuit includes: a voltage conversion circuit for converting 3.3V to 5V and a voltage conversion circuit for converting 5V to 15V.

[0069] Figure 13 It is a schematic structural diagram of an embodiment of the bridge arm signal interlocking and shaping circuit.

[0070] See Figure 13 the example shown. The bridge arm signal interlocking and shaping circuit can perform a NOT operation on the driving signals of the upper and lower bridge arms, and then perform an AND operation on the output of this NOT operation and the driving signals of the upper and lower bridge arms respectively. When the driving signals of the upper and lower bridge arms are both high-level, the output can be made low-level to avoid the situation where the upper and lower bridge arms conduct simultaneously.

[0071] Figure 4 It can schematically illustrate the conversion process of the driving signal of the control board. As described above, in the related solutions, after the control chip issues a driving signal, it is directly output externally through the driving circuit or an output lock is added at the front end of the driving circuit. However, in the solution of the present invention, an external output locking circuit is added at the back end of the driving circuit for outputting to the IGBT drive board.

[0072] In Figure 4In the driving signal detection topology shown, in the control board of the high-power inverter, the driving signal flow diagram includes multiple voltage conversion circuits, bridge arm signal interlocking shaping circuits, and the output locking circuit added at the end of the main control board driving circuit of the present invention. Here, the bridge arm signal interlocking shaping circuit is used to prevent the driving signal level of the same phase from being in a high level state at the same time, and the output locking circuit allows the chip to control whether the final driving signal is output to the IGBT driving board.

[0073] The drive signal is a PWM signal with a certain frequency and a certain duty cycle, which is sent out by the DSP chip pin according to the motor control algorithm. The voltage of the drive signal sent out by the DSP chip pin is 3.3V. Figure 4 As shown, the 3.3V drive signal will continue to be converted into 5V and then into 15V, and the output interlock circuit will interlock the 15V drive signal and output it to the IGBT drive board independent of the main control board. The purpose of the output interlock is to prevent the drive signals of the same phase from being in a high level state at the same time. In the scheme of the present invention, a signal output locking circuit (i.e., an output locking circuit, or an external output locking circuit) will be added to the 15V drive signal at the end of the main control board drive circuit. The purpose is to perform a drive signal detection before the IGBT of the inverter officially works to determine whether the drive circuit is normal.

[0074] In the related schemes, after the control chip sends out the driving signal, it is directly output to the outside through the driving circuit or an output lock is added at the front end of the driving circuit. In the related schemes, the signal detection does not emphasize the locking output of the driving signal and the self-detection technology of the signal detection circuit fault. The scheme of the present invention adds an external output locking signal at the back end of the control board driving circuit, with the purpose of realizing the detection of the driving signal of the driving circuit of the control board before the driving signal is output to the outside.

[0075] In some implementations, the output locking module includes: an AND logic module.

[0076] The AND logic module is configured to perform an AND operation based on the drive signal and the PWM signal to obtain an operation result, so as to lock the output of the drive signal according to the operation result.

[0077] Wherein, the driving signal includes: at least one of an upper bridge arm driving signal and a lower bridge arm driving signal.

[0078] Figure 5 FIG. 1 is a schematic diagram of the structure of an embodiment of an output locking circuit. Figure 5As shown in the figure, the output locking circuit includes: NAND gate U2-A, NAND gate U2-B, NOT gate U3-A, and NOT gate U3-B. The first input terminal (such as pin 1) of NAND gate U2-A is connected to the control signal of the DSP chip. The second input terminal (such as pin 2) of NAND gate U2-A is connected to the upper-bridge-arm drive signal output by the bridge-arm signal interlock shaping circuit. The output terminal (such as pin 3) of NAND gate U2-A is connected to the input terminal (such as pin 1) of NOT gate U3-A, and the output terminal (such as pin 2) of NOT gate U3-A can output to the IGBT drive board. The first input terminal (such as pin 5) of NAND gate U2-B is connected to the control signal of the DSP chip. The second input terminal (such as pin 6) of NAND gate U2-B is connected to the lower-bridge-arm drive signal output by the bridge-arm signal interlock shaping circuit. The output terminal (such as pin 4) of NAND gate U2-B is connected to the input terminal (such as pin 3) of NOT gate U3-B, and the output terminal (such as pin 4) of NOT gate U3-B can output to the IGBT drive board. Of course, in the output locking circuit, it is also possible to directly use an AND gate.

[0079] Figure 5 This is an example circuit of the signal output locking circuit described above. As Figure 5 shown in the figure, in the example diagram of the output locking circuit, mainly an AND operation is performed on the drive signal and the DSP chip control signal. If the DSP chip control signal is at a low level, the outputs are all at a low level. In related solutions, more often a 3.3V to 5V conversion circuit is added at the direct signal output of the control chip, and a conversion enable control signal is added to achieve output locking, that is, output locking is added at the front end of the drive circuit. The solution of the present invention is to use a logic chip at the rear end of the drive circuit to perform an AND operation on the drive signal and the control signal. When the control signal is at a high level, the output of the drive circuit is the drive signal. When the control signal is at a low level, the output of the drive circuit is at a low level.

[0080] Among them, the DSP chip control signal, which is a control signal independent of the PWM drive signal, can be set to a high level or a low level. Its control function is to control whether to allow the drive signal to be output to the IGBT drive board. Once this signal is at a low level, then after performing an AND operation with the drive signal, the outputs are all at a low level, which is equivalent to locking the output of the drive signal to the outside. When the signal is at a high level, then the drive signal is output in whatever state it is.

[0081] In this way, the solution of the present invention locates the fault conditions, interference conditions, and device operation quality conditions of each drive circuit through program calculation and logical judgment. In this way, for the problem that it is difficult to locate the fault position and protect the frequency converter in time when a fault occurs in a certain drive circuit among a series of drive circuits, when a drive fault of the frequency converter occurs, it can be determined which drive circuit the fault comes from, which is convenient for technicians to troubleshoot and repair the faulty circuit, and can accurately locate the position of the faulty circuit. And when a fault occurs, the frequency converter is stopped in time to protect the frequency converter and the equipment controlled by the frequency converter, and can realize the timely protection of the drive fault of the frequency converter.

[0082] In some embodiments, the control unit is further configured to, when the drive unit includes an output locking module, before the frequency converter works, make the output locking module prohibit the output of the drive signal, and after outputting a PWM signal with a set frequency and / or a set duty cycle, determine whether the frequency converter has a drive fault based on one or more of the detection signals in the n drive signals corresponding to the n PWM signals, so that only when the frequency converter does not have a drive fault, the output locking module is allowed to output the drive signal to control the frequency converter to drive and work; and, after the frequency converter works, determine whether the frequency converter has a drive fault based on one or more of the detection signals in the n drive signals corresponding to the n PWM signals.

[0083] Figure 6 It is a schematic flow chart of an embodiment of the signal detection program. As Figure 6 shown, the signal detection program flow chart includes three main processes, namely, the signal detection process before the frequency converter works normally, the signal detection process after the frequency converter works normally, and the self-check process of the detection circuit. That is to say, the control logic of the solution of the present invention in the program is as Figure 6 shown, which is mainly divided into three parts, namely, the drive signal detection before the frequency converter works normally, the drive signal detection after the frequency converter works normally, and the self-check of the detection circuit.

[0084] See Figure 6In the example shown, the drive signal is detected before the frequency converter works properly. The DSP chip controls the output locking circuit to prohibit the drive signal from being output to the IGBT drive board. The DSP chip actively emits a PWM drive signal with a certain frequency and a certain duty cycle. The drive signal feedback circuit feeds back the 6-channel 3.3V signal and the 15V drive signal to the selector. The DSP chip first detects the 15V signal of the U-phase drive circuit. If the relevant signal is detected, it means that this circuit is normal, and the detection of the next 15V drive signal continues. If the 6-channel 15V drive signals are all detected, the 3.3V drive signal does not need to be captured and detected anymore. If the 15V drive signal of the U-phase drive circuit is not detected before, then the 3.3V drive signal of this circuit is selected for capture and detection. If the 3.3V drive signal is detected, it is determined that the drive circuit of this path is faulty, and an early warning and protection are given in time. If the 3.3V drive signal of this path is not detected, the detection circuit enters the self-check state. Through such a self-check before the frequency converter works, the frequency converter can be prevented from starting in the case of a drive circuit fault, and other accidents of the frequency converter and the controlled equipment can be avoided.

[0085] In the solution of the present invention, by adding output locking to the final voltage bit circuit of the drive circuit of the control board, signal detection in different states before and after the frequency converter works is realized. In this way, in the case where a series of drive circuits are interfered by other signals or the devices of a series of drive circuits are abnormal, resulting in abnormal frequency and duty cycle of the drive signal, and the control board is difficult to detect and know such problems, by comparing the frequency and duty cycle of the detection signal with the corresponding configuration of the control program, the abnormal situation of the frequency and duty cycle of the drive signal can be detected. If a large abnormality occurs, it can be determined that the anti-interference ability of the drive circuit is weak or the device is abnormal, which is convenient for technicians to optimize the corresponding circuit.

[0086] In the solution of the present invention, the drive fault of the main control board is detected before the frequency converter works formally, so as to prevent the frequency converter from starting in the state of drive circuit fault. In this way, in view of the problem that it is difficult to know the fault state of a series of drive circuits in the main control board before the frequency converter works formally, and if the frequency converter starts in the case of a series of drive circuit faults in the main control board, the probability of accidents of the frequency converter increases, it can be avoided that the frequency converter starts in the case of drive circuit faults, and the probability of accidents when the frequency converter and the controlled equipment start is reduced.

[0087] In some embodiments, the control unit determines whether the frequency converter has a drive fault based on one or more of the detection signals in the n drive signals corresponding to the n PWM signals, including:

[0088] The control unit is specifically further configured to prohibit the output locking module from outputting the drive signal before the frequency converter works, and after outputting a PWM signal with a set frequency and / or a set duty cycle; or during the operation of the frequency converter, for one of the selected detection signals, use the capture module of the control unit to capture one of the selected detection signals. Correspondingly, for more than one of the detection signals among the n drive signals, use the capture module of the control unit to capture more than one of the detection signals among the n drive signals by capturing one of the selected detection signals one by one.

[0089] The control unit is specifically further configured to, if the capture module can capture more than one of the detection signals, determine that among the n drive units of the frequency converter, more than one of the drive units corresponding to more than one of the detection signals do not have drive faults, and continue to control the operation of the frequency converter.

[0090] The control unit is specifically further configured to, if the capture module fails to capture more than one of the detection signals, determine that among the n drive units of the frequency converter, more than one of the drive units corresponding to more than one of the detection signals have drive faults, and determine the position where the frequency converter has drive faults. The control unit includes: a DSP chip. The capture module in the control unit includes: the CAP module in the DSP chip.

[0091] Among them, being able to capture this detection signal only determines that this drive unit (such as a drive circuit) has no drive fault, and does not mean that the entire frequency converter has no drive fault; being able to successively capture n detection signals can determine that the frequency converter has no drive fault.

[0092] The main idea of signal detection in the solution of the present invention is as Figure 4 shown. The drive signal detection is realized in different states before and after the formal operation of the frequency converter through a signal output locking circuit (i.e., an output locking circuit or an external output locking circuit). The signal feedback circuit (i.e., a 12-way three-phase drive signal feedback circuit) feeds back the 3.3V drive signal output from the DSP chip pin and the 15V drive signal output from the bridge arm interlock shaping circuit (i.e., the bridge arm signal interlock shaping circuit) to the selection circuit (i.e., a 16-way selector).

[0093] Among them, the DSP chip outputs a 3.3V drive signal which is input to the drive circuit of the control board. When drawing the diagram, it was subconsciously defaulted that the drive circuit of the control board includes this 3.3V drive signal. A 16-way selector is used because commonly used ones are 4-way or 8-way selectors, and when more than 8 ways are needed, a 16-way selector can be formed by cascading two 8-way selectors. Actually, 12 ways are used. If it is necessary to change to a 12-way selector, it is also possible. You can refer toFigure 14 The structural topology diagram of the selected 12-way selector shown in the figure.

[0094] Any one of the signals is selected by the selection circuit and input into the DSP chip for CAP module capture detection. According to the capture situation of the CAP module, the status information of the control board drive circuit and the status information of the drive signal are obtained. The drive circuit status information is whether there is a drive fault; the drive signal status information is the frequency and duty cycle information of the PWM signal. Function: Judge whether to start the inverter protection mechanism according to whether there is a drive fault; judge whether the drive circuit distorts the PWM drive signal according to the frequency and duty cycle information of the PWM signal.

[0095] See Figure 5 In the example shown, the output locking circuit of the drive signal is mainly composed of a logic chip, which performs an AND operation on the drive signal and the control signal of the DSP chip. When the control signal of the DSP chip is at a high level, the drive signal can be normally output to the IGBT drive board. The CAP module of the DSP chip can capture the edge event of the input signal (that is, one of the drive signals selected by the 16-way selector), that is, the rising edge or falling edge of the input signal can be captured. Therefore, when facing a drive signal with a frequency of 5 kHz, if more than 50 level changes can be captured within 1 ms, it can be judged that the captured signal is the drive signal. In addition, by counting the time from the rising edge to the next rising edge, the signal period and frequency can be calculated, and the duty cycle of the signal can be calculated by counting the time from the rising edge to the falling edge.

[0096] See Figure 6The example shown is the detection of the drive signal after the frequency converter works normally. If it is determined that each drive circuit is normal during the detection of the drive signal before the frequency converter works normally, the frequency converter can work officially. The DSP chip controls the output locking circuit to enable the drive signal to be output to the IGBT drive board. During the normal operation of the frequency converter, the drive signal is detected. First, it is judged whether the duty cycle of the PWM drive signal configured in the program is 0 or 100%. Only when the duty cycle of the PWM drive signal is not in these two states will there be a change in the level, and only when there is a change in the level can it be captured by the CAP module of the DSP chip. During the normal operation of the frequency converter, the drive signal feedback circuit feeds back the 3.3V drive signal and the 15V drive signal of 6 channels to the selector. The DSP chip first detects the 15V signal of the U-phase drive circuit. If the relevant signal is detected, it means that this circuit is normal, and the detection of the next 15V drive signal continues. If the 15V drive signals of 6 channels are all detected, there is no need to detect the 3.3V drive signal anymore. If the 15V drive signal of the U-phase drive circuit cannot be detected previously, then the 3.3V drive signal of this circuit is selected for detection. If the 3.3V drive signal is detected, it is determined that there is a fault in this drive circuit, and an early warning protection is given in time. If the 3.3V drive signal of this circuit cannot be detected, it enters the self-check state of the detection circuit. The corresponding frequency and duty cycle of the captured drive signal can be calculated in the program, and these data are compared with the data configured by the program algorithm. The comparison of the two sets of data can be used as a reference for technicians to optimize the drive circuit or compensate and optimize the algorithm of the duty cycle configured in the program.

[0097] In some embodiments, the control unit determines the position where the drive fault occurs in the frequency converter, including:

[0098] The control unit is specifically further configured to determine whether a signal with a set voltage level, such as a 3.3V voltage level signal, is captured.

[0099] The control unit is specifically further configured to, if the signal with the set voltage level is captured, determine that at least some of the n drive units have failed.

[0100] The control unit is specifically further configured to, if the signal with the set voltage level is not captured, initiate a self-check signal to detect whether the detection unit has failed according to the self-check signal.

[0101] The solution of the present invention can realize the self - detection of faults in the detection circuit. In this way, for the situation where a fault occurs in the detection circuit of the IGBT drive signal, it is difficult to distinguish whether it is a series of drive circuit faults or a fault in the detection circuit of the IGBT drive signal, and false alarms of IGBT drive faults are likely to occur. When the drive signal output by the DSP chip pin is not detected, the self - detection of faults in the detection circuit can be realized, and the self - detection of faults in the drive signal detection circuit can be achieved, avoiding false alarms of the drive faults of the main control board of the frequency converter.

[0102] Figure 5 It is an example circuit of the signal output locking circuit described above. As Figure 5 shown, in the example diagram of the output locking circuit, mainly the drive signal and the DSP chip control signal are AND - operated. If the DSP chip control signal is at a low level, the outputs are all at a low level. In related solutions, more often a 3.3V - to - 5V conversion circuit is added at the direct signal output of the control chip, and a conversion enable control signal is added to achieve output locking, that is, output locking is added at the front end of the drive circuit. The solution of the present invention is to use a logic chip at the rear end of the drive circuit, perform an AND operation on the drive signal and the control signal. When the control signal is at a high level, the output of the drive circuit is the drive signal. When the control signal is at a low level, the output of the drive circuit is at a low level.

[0103] In this way, the solution of the present invention can, through program calculation and logical judgment, locate the fault situation, interference situation, and device operation quality situation of each drive circuit. In this way, for the problem that it is difficult to locate the fault position and timely protect the frequency converter when a fault occurs in a certain drive circuit in a series of drive circuits, when a drive fault of the frequency converter occurs, the fault can be located in which drive circuit, which is convenient for technicians to check and repair the faulty circuit, and can accurately locate the position of the faulty circuit. And when a fault occurs, the frequency converter is stopped in time to protect the frequency converter and the equipment controlled by the frequency converter, and timely protection of the drive fault of the frequency converter can be achieved.

[0104] In some embodiments, the control unit detects whether the detection unit has a fault according to the detection signal, including:

[0105] The control unit is specifically further configured to send the self - detection signal to the detection unit and determine whether the capture module of the control unit captures the self - detection signal.

[0106] The control unit is specifically further configured to, when the detection unit includes a signal feedback module and a selection module, if the capture module captures the self - detection signal, determine that the signal feedback module has a fault. If the capture module does not capture the self - detection signal, determine that the selection module has a fault.

[0107] SeeFigure 6 In the example shown, the detection circuit performs self-check. When the DSP chip fails to detect the 3.3V drive signal of the PWM, it enters the self-check state of the detection circuit. Since the 3.3V drive signal is directly output by the DSP chip's pin, if it cannot be detected, the probability of a fault in the detection circuit is extremely high. The self-check logic is that the DSP chip actively sends a PWM signal with a certain frequency and a certain duty cycle directly to the selector circuit. If the DSP chip can detect this signal at the output section of the selector, it is determined that the drive feedback circuit is faulty and the selector circuit is normal. If this signal cannot be detected, it is determined that the selector circuit is faulty. Through such a self-check logic, the misreport of drive faults in the main control board of the frequency converter can be greatly reduced.

[0108] It should be noted that in the above embodiments, the parameters of the feedback circuit included are only for demonstration. The actual voltage value of the drive signal should be determined according to the actual situation. In addition, it includes but is not limited to 6 drive signals, signal voltage conversion values, signal detection sequences, etc.

[0109] In the solution of the present invention, the CAP module of the DSP chip is used to detect the frequency and duty cycle of the signal, and a multi-channel comparator is used as the signal feedback circuit, which can locate the drive fault in a specific circuit. There are two modes for detecting drive circuit faults before and after the frequency converter works. The detection circuit can realize fault self-check. It can solve the key technical problems of multi-channel drive circuit fault location, abnormal drive signal state detection, and avoid the frequency converter from starting in the drive circuit fault state. At the same time, it realizes the fault self-check of the detection circuit and avoids the misreport of drive circuit faults in the frequency converter.

[0110] Adopting the technical solution of the present invention, by setting a detection circuit between a series of drive circuits in the control board of the frequency converter and the DSP chip, through this detection circuit, the drive signals of a series of drive circuits in the main control board of the frequency converter are detected, so that when an IGBT module drive fault occurs in the frequency converter, it can be accurately located whether the fault is in the main control board drive circuit or the IGBT drive board. Thus, by detecting the drive signals of a series of drive circuits in the main control board of the frequency converter, when an IGBT module drive fault occurs, the fault location can be accurately determined and protected, which is beneficial to improving the working reliability of the frequency converter.

[0111] According to an embodiment of the present invention, there is also provided a frequency converter corresponding to the control device of the main control board of the frequency converter. The frequency converter may include: the control device of the main control board of the frequency converter described above.

[0112] Since the processing and functions implemented by the frequency converter in this embodiment are basically corresponding to the embodiments, principles, and examples of the foregoing device, for the parts not described in detail in the description of this embodiment, reference can be made to the relevant descriptions in the foregoing embodiments, which will not be elaborated herein.

[0113] By adopting the technical solution of the present invention, a detection circuit is arranged between a series of drive circuits in the control board of the frequency converter and the DSP chip. Through this detection circuit, the drive signals of a series of drive circuits in the main control board of the frequency converter are detected. When an IGBT module drive fault occurs in the frequency converter, it can accurately locate whether the fault is in the drive circuit of the main control board or in the drive board of the IGBT, which can greatly shorten the troubleshooting difficulty and troubleshooting time of technicians. In addition, the state of the drive signal can be clearly understood, and then the interference situation of the drive circuit of the main control board or the operation quality of the drive device can be judged.

[0114] According to an embodiment of the present invention, there is also provided a control method for the main control board of a frequency converter corresponding to the frequency converter, as Figure 7 shown in the flowchart of an embodiment of the method of the present invention. The main control board of the frequency converter includes: a drive unit and a control unit. The number of the drive units is n, and n is a positive integer. The drive unit, such as a drive circuit, may specifically be a control board drive circuit. The control unit, such as a DSP chip. The control method for the main control board of the frequency converter includes: step S110 to step S150.

[0115] In step S110, a PWM signal is sent through the control unit, and the number of paths of the PWM signal is n.

[0116] In step S120, through the drive unit, drive signals are output according to the PWM signal. The number of paths of the drive signals is the same as the number of paths of the PWM signal. Corresponding to the number of paths of the PWM signal, the number of paths of the drive signals is also n.

[0117] In step S130, a selection signal is also sent through the control unit. The selection signal is a signal for selecting one of the n drive signals corresponding to the n PWM signals.

[0118] In step S140, through the detection unit, one of the n drive signals corresponding to the n PWM signals is selected as a detection signal according to the selection signal. The detection unit is arranged between the drive unit and the control unit. The detection unit, such as a detection circuit.

[0119] At step S150, through the control unit, based on one or more of the detection signals among the n drive signals corresponding to the n PWM signals, it is determined whether a drive fault occurs in the frequency converter, so as to start a preset protection mechanism, such as power-off or shutdown protection, when a drive fault occurs in the frequency converter. Among them, one or more of the detection signals include: one selected detection signal. That is to say, in one judgment, according to the selected drive signal, it is determined whether a drive fault occurs in the frequency converter.

[0120] In order to accurately locate whether the drive circuit of the main control board fails or the drive board of the IGBT fails when a drive fault occurs in the IGBT module of the frequency converter. The solution of the present invention provides a method for detecting drive signals on the main control board, which greatly shortens the troubleshooting difficulty and time for technicians. In addition, the state of the drive signal can be clearly understood, and then the interference situation of the drive circuit of the main control board or the operation quality of the drive device can be judged. A self-check method for the signal detection circuit is also provided, reducing the situation of false alarms of drive faults.

[0121] Specifically, the solution of the present invention provides a method for detecting drive signals of the main control board of a frequency converter. Using a multiplexer, the signals of each drive circuit in a series of drive circuits are fed back to the CAP (pulse detection) module of the DSP chip. Capture the level change of the fed-back drive signal to detect the conduction situation, signal frequency and duty cycle of each drive circuit.

[0122] In this way, aiming at the problem that it is difficult to ensure that a series of drive circuits always maintain a good state during production or operation of the control board (i.e., the main control board), the drive signal is fed back to the DSP chip for signal level change judgment, so as to know the specific state of the drive signal and the conduction situation of the drive circuit, and it is possible to realize real-time detection of the conduction situation of a series of drive circuits for the drive signal.

[0123] In some embodiments, the detection unit includes: a signal feedback module and a selection module. The signal feedback module, such as a 12-way three-phase drive signal feedback circuit. The selection module, such as a 16-way selector.

[0124] Among them, in step S140, the specific process of selecting one drive signal from the n drive signals corresponding to the n PWM signals according to the selection signal through the detection unit is as follows in the following exemplary description.

[0125] The following combines Figure 8 The schematic flow chart of an embodiment of selecting one drive signal in the method of the present invention shown, and further illustrates the specific process of selecting one drive signal in step S140, including: step S210 and step S220.

[0126] Step S210: The number of the signal feedback modules is n. Through each of the n signal feedback modules, for one of the n drive signals corresponding to the n PWM signals, compare the parameters of one drive signal with the set parameter range to obtain a comparison result, which is used as one feedback signal. The n signal feedback modules can obtain n comparison results, which are used as the n feedback signals of the n drive signals.

[0127] Step S220: Through the selection module, according to the selection signal, select one of the feedback signals from the feedback signals of the n drive signals as one detection signal.

[0128] The solution of the present invention is used for detecting drive signals on the main control board of a high-power frequency converter. To enable those skilled in the art to more clearly understand the embodiments of the present invention, the following combines specific operations and refers to Figures 2 to 6 the example shown to clearly and completely describe the technical solutions in the embodiments of the present invention in an exemplary manner.

[0129] The following gives an exemplary description of the voltage conversion of drive signals on the main control board of the frequency converter.

[0130] Figure 2 It is a schematic structural diagram of an embodiment of a drive signal detection topology. As Figure 2 shown, the drive signal detection topology includes: a signal drive circuit, a drive signal feedback circuit, a signal selection circuit, and a DSP chip control circuit. Among them, the signal drive circuit is, for example, a control board drive circuit. The drive signal feedback circuit is, for example, a 12-way three-phase drive signal feedback circuit. The signal selection circuit is, for example, a 16-way selector. The DSP chip control circuit is, for example, a DSP chip. That is to say, specifically, the drive signal detection topology includes: a control board drive circuit (i.e., the drive circuit of the control board), a 12-way three-phase drive signal feedback circuit, a 16-way selector, and a DSP chip. The control circuit drive board, the 12-way three-phase drive signal feedback circuit, the 16-way selector, and the DSP chip are connected in sequence. The 12-way three-phase drive signal feedback circuit and the 16-way selector constitute the detection circuit of the control board drive circuit. The DSP chip sends a selection signal and a detection circuit self-check signal to the 16-way selector, and the DS chip sends a PWM signal and an output lock signal to the control board drive circuit.

[0131] In the related solutions, the signal feedback detection circuit only detects the fault conditions of the drive circuit, and the probability of the feedback detection circuit having a fault is relatively high, and false alarms of faults are likely to occur. The solution of the present invention adds a detection circuit self-check signal to the 16-way selector circuit to avoid false alarms of drive circuit faults when the feedback fails.

[0132] In some embodiments, the driving unit includes a voltage conversion module, a bridge arm signal interlock module, and an output locking module. The voltage conversion module, the bridge arm signal interlock module, and the output locking module are sequentially arranged between the control unit such as a DSP chip and the IGBT driving board of the frequency converter. The voltage conversion module is, for example, a voltage conversion circuit. The bridge arm signal interlock module is, for example, a bridge arm signal interlock shaping circuit. The output locking module is, for example, an output locking circuit. Among them,

[0133] For the specific process of outputting a driving signal through the driving unit according to the PWM signal in step S120, refer to the following exemplary description.

[0134] The following Figure 9 Combined with the schematic flow diagram of an embodiment of outputting a driving signal in the method of the present invention shown, the specific process of outputting a driving signal in step S120 is further described, including: step S310 to step S330.

[0135] Step S310: Through the voltage conversion module, convert the voltage of the PWM signal to obtain a signal with a set voltage.

[0136] Step S320: Through the bridge arm signal interlock module, based on the signal with the set voltage, perform an interlock process on the upper and lower bridge arms of the IGBT driving board of the frequency converter, and then output the driving signal.

[0137] Step S330: Through the output locking module, lock the driving signal before the frequency converter works to prohibit the IGBT driving board of the frequency converter from starting based on the driving signal.

[0138] Figure 4 It is a schematic diagram of the signal flow direction of an embodiment of the control board driving circuit. As Figure 4 shown, the control board driving circuit includes: a DSP chip, a voltage conversion circuit, a bridge arm signal interlock shaping circuit, an output locking circuit, and an IGBT driving board connected in sequence. Among them, the voltage conversion circuit includes: a 3.3V to 5V voltage conversion circuit and a 5V to 15V voltage conversion circuit.

[0139] Figure 4 It can schematically illustrate the conversion process of the driving signal of the control board. As described above, in the related solutions, after the control chip issues a driving signal, it is directly output externally through the driving circuit or an output lock is added at the front end of the driving circuit. However, in the solution of the present invention, an external output locking circuit is added at the back end of the driving circuit for outputting to the IGBT driving board.

[0140] In Figure 4In the driving signal detection topology shown, in the control board of a high-power frequency converter, the driving signal flow diagram includes multiple voltage conversion circuits, an interlock shaping circuit for bridge arm signals, and an output locking circuit added at the end of the driving circuit of the present invention's solution on the main control board. Here, the purpose of the interlock shaping circuit for bridge arm signals is to prevent the driving signal levels of the same phase from being at a high level simultaneously. The output locking circuit can enable the chip to control whether the final driving signal is output to the IGBT driving board.

[0141] The driving signal is a PWM signal with a certain frequency and a certain duty cycle emitted by the pins of the DSP chip according to the control method. The voltage of the driving signal emitted by the pins of the DSP chip is 3.3V. As Figure 4 shown, the 3.3V driving signal will be continuously converted to 5V and then to 15V. The output interlock circuit interlocks the 15V driving signal and outputs it to the IGBT driving board independent of the main control board. The purpose of output interlock is to prevent the driving signals of the same phase from being at a high level simultaneously. In the solution of the present invention, a signal output locking circuit (i.e., the output locking circuit or the external output locking circuit) will be added at the 15V driving signal at the end of the driving circuit on the main control board. The purpose is to perform a driving signal detection once before the IGBT of the frequency converter officially works to determine whether the driving circuit is normal.

[0142] In related solutions, after the control chip emits the driving signal, it is directly output externally through the driving circuit or an output lock is added at the front end of the driving circuit. In related solutions, signal detection does not emphasize the locking output of the driving signal and the self-check technology for signal detection circuit faults. In the solution of the present invention, an external output locking signal is added at the rear end of the driving circuit on the control board, and the purpose is to enable the driving signal of the driving circuit on the control board to be detected before the driving signal is output externally.

[0143] In some embodiments, it further includes: through the control unit, when the driving unit includes an output locking module, before the frequency converter works, the output locking module is prohibited from outputting the driving signal, and after outputting a PWM signal with a set frequency and / or a set duty cycle, based on one or more of the detection signals among the n driving signals corresponding to the n PWM signals, it is determined whether the frequency converter has a driving fault, so that only when the frequency converter does not have a driving fault, the output locking module is allowed to output the driving signal to control the frequency converter to drive and work; and, after the frequency converter works, based on one or more of the detection signals among the n driving signals corresponding to the n PWM signals, it is determined whether the frequency converter has a driving fault.

[0144] Figure 6 It is a schematic flowchart of an embodiment of the signal detection program. As Figure 6As shown in the figure, the signal detection program flowchart includes three main processes, namely, the signal detection process before the frequency converter works normally, the signal detection process after the frequency converter works normally, and the self-check process of the detection circuit. That is to say, the control logic of the solution of the present invention in the program is as Figure 6 shown, which is mainly divided into three parts, namely, the drive signal detection before the frequency converter works normally, the drive signal detection after the frequency converter works normally, and the self-check of the detection circuit.

[0145] Refer to Figure 6 the example shown for the drive signal detection before the frequency converter works normally. The DSP chip controls the output locking circuit to prohibit the drive signal from being output to the IGBT drive board. The DSP chip actively issues a PWM drive signal with a certain frequency and a certain duty cycle. The drive signal feedback circuit feeds back the 6-channel 3.3V signal and the 15V drive signal to the selector. The DSP chip first detects the 15V signal of the U-phase drive circuit. If the relevant signal is detected, it means that this circuit is normal, and the detection of the next 15V drive signal continues. If the 15V drive signals of all 6 channels are detected, the 3.3V drive signal does not need to be captured and detected anymore. If the 15V drive signal of the U-phase drive circuit is not detected before, then the 3.3V drive signal of this circuit is selected for capture and detection. If the 3.3V drive signal is detected, it is determined that the drive circuit of this path is faulty, and an early warning and protection are given in time. If the 3.3V drive signal of this path is not detected, the detection circuit enters the self-check state. Through such a self-check before the frequency converter works, the frequency converter can be prevented from starting in the case of a drive circuit failure, and other accidents of the frequency converter and the controlled equipment can be avoided.

[0146] The solution of the present invention realizes the signal detection in different states before and after the frequency converter works by adding output locking to the final voltage bit circuit of the drive circuit of the control board. In this way, aiming at the situation where the frequency and duty cycle of the drive signal are abnormal when a series of drive circuits are interfered by other signals or the devices of a series of drive circuits are abnormal, and it is difficult for the control board to detect and know such problems, by comparing the frequency and duty cycle of the detection signal with the corresponding configuration of the control program, the abnormal situation of the frequency and duty cycle of the drive signal can be detected. If a large abnormality occurs, it can be located that the anti-interference ability of the drive circuit is weak or the device is abnormal, which is convenient for technicians to optimize the corresponding circuit.

[0147] The solution of the present invention detects the drive fault of the main control board before the frequency converter works formally, and avoids the frequency converter from starting in the state of drive circuit failure. In this way, aiming at the problem that it is difficult to know the fault state of a series of drive circuits in the main control board before the frequency converter works formally, and if the frequency converter starts in the case of a series of drive circuit faults in the main control board, the probability of accidents of the frequency converter increases, it can be avoided that the frequency converter starts in the case of drive circuit failure, and the probability of accidents when the frequency converter and the controlled equipment start is reduced.

[0148] In some embodiments, in step S150, through the control unit, based on one or more of the detection signals in the n drive signals corresponding to the n PWM signals, the specific process of determining whether a drive fault occurs in the frequency converter is as follows in the following exemplary description.

[0149] The following combines Figure 10 The flowchart of an embodiment for determining whether a drive fault occurs in the frequency converter in the method of the present invention shown below further illustrates the specific process of determining whether a drive fault occurs in step S150, including: step S410 to step S430.

[0150] Step S410, through the control unit, after the output lock module is prohibited from outputting the drive signal before the frequency converter works and a PWM signal with a set frequency and / or a set duty cycle is output; or during the operation of the frequency converter, for one selected detection signal, use the capture module of the control unit to capture the selected detection signal. Correspondingly, for one or more of the detection signals in the n drive signals, use the capture module of the control unit to capture one or more of the detection signals in the n drive signals by capturing each selected detection signal one by one.

[0151] Step S420, through the control unit, if the capture module can capture one or more of the detection signals, it is determined that one or more of the drive units corresponding to one or more of the detection signals in the n drive units of the frequency converter do not have a drive fault, and continue to control the frequency converter to work.

[0152] Step S430, through the control unit, if the capture module cannot capture one or more of the detection signals, it is determined that one or more of the drive units corresponding to one or more of the detection signals in the n drive units of the frequency converter have a drive fault, and the position where the drive fault occurs in the frequency converter is determined. The control unit includes: a DSP chip. The capture module in the control unit includes: the CAP module in the DSP chip.

[0153] The main idea of signal detection in the solution of the present invention is as Figure 4As shown, the drive signal detection is realized by a signal output locking circuit (i.e., an output locking circuit or an external output locking circuit) under different states before and after the formal operation of the frequency converter. The signal feedback circuit (i.e., a 12-channel three-phase drive signal feedback circuit) feeds back the 3.3V drive signal output from the pins of the DSP chip and the 15V drive signal output from the bridge arm interlock shaping circuit (i.e., the bridge arm signal interlock shaping circuit) to the selection circuit (i.e., a 16-channel selector). The DSP chip selects any one of the signals and inputs it into the DSP chip for CAP module capture detection, and obtains the status information of the control board drive circuit and the status information of the drive signal according to the capture situation of the CAP module.

[0154] See Figure 5 In the example shown, the output locking circuit of the drive signal is mainly composed of logic chips, which performs an AND operation on the drive signal and the control signal of the DSP chip. When the control signal of the DSP chip is at a high level, the drive signal can be normally output to the IGBT drive board. The CAP module of the DSP chip can capture the edge events of the input signal, that is, it can capture the rising edge or falling edge of the input signal. Therefore, when facing a drive signal with a frequency of 5kHz, if more than 50 level changes can be captured within 1ms, it can be determined that the captured signal is the drive signal. In addition, by counting the time from the rising edge to the next rising edge, the signal period and frequency can be calculated, and by counting the time from the rising edge to the falling edge, the signal duty cycle can be calculated.

[0155] See Figure 6Example shown: Detection of drive signals after the frequency converter operates normally. If all drive circuits are determined to be normal during the drive signal detection before the frequency converter operates normally, the frequency converter can start working officially. The DSP chip controls the output locking circuit to enable the drive signal to be output to the IGBT drive board. During the normal operation of the frequency converter, drive signal detection is carried out. First, it is judged whether the duty cycle of the PWM drive signal configured in the program is 0 or 100%. Only when the duty cycle of the PWM drive signal is not in these two states will there be a level change, and the level change can be captured by the CAP module of the DSP chip. During the normal operation of the frequency converter, the drive signal feedback circuit feeds back the 3.3V drive signals and 15V drive signals of 6 channels to the selector. The DSP chip first detects the 15V signal of the U-phase drive circuit. If the relevant signal is detected, it means that this circuit is normal, and the detection of the next 15V drive signal continues. If the 15V drive signals of 6 channels are all detected, there is no need to detect the 3.3V drive signals anymore. If the 15V drive signal of the U-phase drive circuit cannot be detected previously, then the 3.3V drive signal of this circuit is selected for detection. If the 3.3V drive signal is detected, it is judged that there is a fault in this drive circuit, and early warning and protection are carried out in time. If the 3.3V drive signal of this circuit cannot be detected, it enters the self-check state of the detection circuit. The corresponding frequency and duty cycle of the captured drive signal can be calculated in the program, and these data are compared with the data configured by the program algorithm. The comparison of the two sets of data can be used as a reference for technicians to optimize the drive circuit or compensate and optimize the duty cycle algorithm of the program configuration.

[0156] In some embodiments, in step S430, the specific process of determining the position where the drive fault occurs in the frequency converter by the control unit is as follows in the following exemplary description.

[0157] The following combines Figure 11 A schematic flowchart of an embodiment of determining the position where the drive fault occurs in the frequency converter in the method of the present invention shown, further illustrating the specific process of determining the position where the drive fault occurs in step S430, including: step S510 to step S530.

[0158] Step S510, determine whether a signal with a set voltage level, such as a 3.3V voltage level signal, is captured by the control unit.

[0159] Step S520, if the signal with the set voltage level is captured by the control unit, determine that at least some of the n drive units have faults.

[0160] Step S530, if the signal with the set voltage level is not captured by the control unit, initiate a self-check signal to detect whether the detection unit has a fault according to the self-check signal.

[0161] The solution of the present invention can realize the self - detection of faults in the detection circuit. In this way, for the situation where a fault occurs in the detection circuit of the IGBT drive signal, it is difficult to distinguish whether it is a series of drive circuit faults or a fault in the IGBT drive signal detection circuit, and false alarms of IGBT drive faults are likely to occur. When the drive signal output from the DSP chip pin is not detected, the self - detection of faults in the detection circuit can be realized, and the self - detection of faults in the drive signal detection circuit can be achieved, avoiding false alarms of the drive faults of the main control board of the frequency converter.

[0162] In some embodiments, in step S530, through the control unit, according to the detection signal, the specific process of detecting whether the detection unit has a fault is as follows in the following exemplary description.

[0163] The following combines Figure 12 The schematic flowchart of an embodiment of detecting whether the detection unit has a fault in the method of the present invention shown, and further illustrates the specific process of detecting whether the detection unit has a fault in step S530, including: step S610 and step S620.

[0164] Step S610, through the control unit, send the self - detection signal to the detection unit, and determine whether the capture module of the control unit captures the self - detection signal.

[0165] Step S620, when the detection unit includes a signal feedback module and a selection module through the control unit, if the capture module captures the self - detection signal, it is determined that the signal feedback module has a fault. If the capture module does not capture the self - detection signal, it is determined that the selection module has a fault.

[0166] Refer to Figure 6 The example shown for the self - detection of the detection circuit. When the DSP chip cannot detect the 3.3V drive signal of the PWM, it enters the self - detection state of the detection circuit. Since the 3.3V drive signal is the signal directly output from the DSP chip pin, if it cannot be detected, the probability of a fault in the detection circuit is extremely high. The self - detection logic is that the DSP chip actively sends a PWM signal with a certain frequency and a certain duty cycle directly to the selector circuit. If the DSP chip can detect this signal at the output section of the selector, it is determined that the drive feedback circuit has a fault and the selector circuit is normal. If this signal cannot be detected, it is determined that the selector circuit has a fault. Through such a self - detection logic, the false alarms of the drive faults of the main control board of the frequency converter can be greatly reduced.

[0167] It should be noted that in the above - mentioned embodiments, the parameters of the feedback circuit included are only for demonstration, and the actual voltage value of the drive signal should be determined according to the actual situation. In addition, it includes but is not limited to 6 - way drive signals, signal voltage conversion values, signal detection sequences, etc.

[0168] In the solution of the present invention, the frequency and duty cycle of the signal are detected by the CAP module of the DSP chip, and a multi-channel comparator is used as the signal feedback circuit, which can locate that the driving fault comes from a specific circuit. There are two modes for detecting the driving circuit fault before and after the frequency converter works, and the detection circuit can realize self-diagnosis of faults. It can solve the key technical problems of multi-channel driving circuit fault location, abnormal detection of driving signal status, and avoid the frequency converter from starting in the driving circuit fault state. At the same time, it realizes self-diagnosis of the detection circuit fault and avoids false alarms of the driving circuit fault in the frequency converter.

[0169] Since the processing and functions implemented by the method of this embodiment are basically corresponding to the foregoing embodiments, principles and examples of the frequency converter, for the details not described in the description of this embodiment, reference can be made to the relevant descriptions in the foregoing embodiments and will not be elaborated here.

[0170] By adopting the technical solution of this embodiment, for a series of driving circuits in the control board of the frequency converter, a detection circuit is set between the series of driving circuits and the DSP chip. Through this detection circuit, the driving signals of a series of driving circuits in the main control board of the frequency converter are detected, so that when an IGBT module driving fault occurs in the frequency converter, it can be accurately located whether the fault occurs in the main control board driving circuit or the IGBT driving board. Before the frequency converter officially works, the main control board driving fault is detected to avoid the frequency converter from starting in the driving circuit fault state.

[0171] In summary, it is easy for those skilled in the art to understand that, on the premise of no conflict, the above advantageous ways can be freely combined and superimposed.

[0172] The above are only the embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A control device for the main control board of a frequency converter, characterized in that, The main control board of the frequency converter includes: a drive unit and a control unit; the drive unit is arranged between the control unit and the IGBT drive board of the frequency converter; the number of the drive units is n, and n is a positive integer; the control device of the main control board of the frequency converter includes: a detection unit; the detection unit includes: a signal feedback module and a selection module; wherein, the control unit is configured to send a PWM signal, and the number of paths of the PWM signal is n; the drive unit is configured to output a drive signal according to the PWM signal to avoid simultaneous conduction of the upper and lower bridge arms of the IGBT drive board of the frequency converter; the number of paths of the drive signal is the same as the number of paths of the PWM signal; the control unit is further configured to send a selection signal; the selection signal is a signal for selecting one drive signal from n drive signals corresponding to n paths of the PWM signal; the detection unit is configured to select one drive signal from n drive signals corresponding to n paths of the PWM signal as a detection signal according to the selection signal; the control unit is further configured to determine whether a drive fault occurs in the frequency converter based on one or more of the detection signals among n drive signals corresponding to n paths of the PWM signal, so as to start a preset protection mechanism when a drive fault occurs in the frequency converter; wherein, one or more of the detection signals include: the selected one detection signal; Wherein, the frequency and duty cycle of the detection signal are compared with the corresponding configuration of the control program to detect the abnormal situation of the frequency and duty cycle of the drive signal. If a large abnormality occurs, it is located that the anti-interference ability of the drive circuit is weak or the device is abnormal; When the control unit does not detect a drive signal, the detection unit failure self-check is realized: the control unit actively sends a PWM signal with a certain frequency and a certain duty cycle to the selection module. If the control unit can detect this signal at the output section of the selection module, it is determined that the signal feedback module fails and the selection module is normal; if this signal cannot be detected, it is determined that the selection module fails.

2. The control device of the main control board of the frequency converter according to claim 1, characterized in that, Wherein, the detection unit selects one drive signal from n drive signals corresponding to n paths of the PWM signal according to the selection signal, including: the number of the signal feedback modules is n paths. Each of the n signal feedback modules is configured to compare the parameters of one drive signal with a set parameter range for one drive signal among n drive signals corresponding to n paths of the PWM signal to obtain a comparison result as one feedback signal; the n comparison results that can be obtained by the n signal feedback modules are used as the n feedback signals of the n drive signals; the selection module is configured to select one feedback signal from the feedback signals of the n drive signals as one detection signal according to the selection signal.

3. The control device of the main control board of the frequency converter according to claim 2, characterized in that, One signal feedback module includes: a comparator module; wherein, The inverting input terminal of the comparator module can input the set parameter range; the non-inverting input terminal of the comparator module can input one path of the drive signal; the output terminal of the comparator module can output one path of the feedback signal.

4. The control device of the main control board of the frequency converter according to claim 1, characterized in that, The drive unit includes: a voltage conversion module, a bridge arm signal interlock module, and an output lock module; wherein, The drive unit outputs a drive signal according to the PWM signal, including: The voltage conversion module is configured to convert the voltage of the PWM signal to obtain a signal with a set voltage; The bridge arm signal interlock module is configured to perform an interlock process on the upper and lower bridge arms of the IGBT drive board of the frequency converter based on the signal with the set voltage, and then output the drive signal; The output lock module is configured to lock the drive signal before the frequency converter works, so as to prohibit the IGBT drive board of the frequency converter from starting based on the drive signal.

5. The control device of the main control board of the frequency converter according to claim 4, characterized in that, The output lock module includes: an AND logic module; wherein, The AND logic module is configured to perform an AND operation on the drive signal and the PWM signal to obtain an operation result, so as to lock the output of the drive signal according to the operation result; Wherein, the drive signal includes at least one of an upper bridge arm drive signal and a lower bridge arm drive signal.

6. The control device of the main control board of the frequency converter according to claim 1, characterized in that The control unit is further configured to, when the drive unit includes an output lock module, before the frequency converter works, make the output lock module prohibit the output of the drive signal, and after outputting a PWM signal with a set frequency and / or a set duty cycle, determine whether the frequency converter has a drive fault based on one or more of the detection signals corresponding to the n paths of drive signals corresponding to the n paths of PWM signals, so as to, when the frequency converter does not have a drive fault, make the output lock module allow the drive signal to control the frequency converter to drive and work; And, after the frequency converter works, determine whether the frequency converter has a drive fault based on one or more of the detection signals corresponding to the n paths of drive signals corresponding to the n paths of PWM signals.

7. The control device of the main control board of the frequency converter according to any one of claims 1 to 6, characterized in that, The control unit determines whether the frequency converter has a drive fault based on one or more of the detection signals corresponding to the n paths of drive signals corresponding to the n paths of PWM signals, including: For one or more of the detection signals among the n paths of drive signals, use the capture module of the control unit to capture one or more of the detection signals among the n paths of drive signals; If the capture module can capture one or more of the detection signals, it is determined that one or more of the drive units corresponding to one or more of the detection signals among the n drive units of the frequency converter do not have a drive fault, and continue to control the frequency converter to work; If the capture module cannot capture one or more of the detection signals, it is determined that one or more of the drive units corresponding to one or more of the detection signals among the n drive units of the frequency converter have a drive fault, and the position where the frequency converter has a drive fault is determined.

8. The control device of the main control board of the frequency converter according to claim 6, characterized in that, The control unit determines the position where a drive fault occurs in the frequency converter, including: Determining whether a signal with a set voltage level is captured; If the signal with the set voltage level is captured, determining that at least some of the n drive units have a fault; If the signal with the set voltage level is not captured, initiating a self-check signal to detect whether the detection unit has a fault based on the self-check signal.

9. The control device of the main control board of the frequency converter according to claim 8, characterized in that, The control unit detects whether the detection unit has a fault according to the detection signal, including: Sending the self-check signal to the detection unit and determining whether the capture module of the control unit captures the self-check signal; When the detection unit includes a signal feedback module and a selection module, if the capture module captures the self-check signal, determining that the signal feedback module has a fault; if the capture module does not capture the self-check signal, determining that the selection module has a fault.

10. A frequency converter, characterized in that, Including: The control device of the main control board of the frequency converter according to any one of claims 1 to 9.

11. A control method for a main control board of a frequency converter as described in claim 10, characterized in that, The main control board of the frequency converter includes: a drive unit and a control unit; the number of drive units is n, where n is a positive integer; the control method of the main control board of the frequency converter includes: Sending a PWM signal through the control unit, and the number of paths of the PWM signal is n; Outputting a drive signal through the drive unit according to the PWM signal; the number of paths of the drive signal is the same as the number of paths of the PWM signal; The control unit also issues a selection signal; the selection signal is a signal for selecting one drive signal from the n drive signals corresponding to the n PWM signals; Selecting one drive signal from the n drive signals corresponding to the n PWM signals as a detection signal through the detection unit according to the selection signal; The control unit also determines whether the frequency converter has a drive fault based on one or more of the detection signals among the n drive signals corresponding to the n PWM signals, so as to activate a preset protection mechanism when the frequency converter has a drive fault; where one or more of the detection signals include: the selected one detection signal.

12. The control method of the main control board of the frequency converter according to claim 11, characterized in that, The detection unit includes: a signal feedback module and a selection module; where Selecting one drive signal from the n drive signals corresponding to the n PWM signals through the detection unit according to the selection signal includes: The number of the signal feedback modules is n. Through each of the n signal feedback modules, for one drive signal among the n drive signals corresponding to the n PWM signals, comparing the parameters of the one drive signal with a set parameter range to obtain a comparison result as one feedback signal; the n comparison results that the n signal feedback modules can obtain are used as the n feedback signals of the n drive signals. Through a selection module, according to the selection signal, one feedback signal is selected from the feedback signals of n channels of the drive signals as one detection signal.

13. The control method of the main control board of the frequency converter according to claim 11, characterized in that, The drive unit includes: a voltage conversion module, a bridge arm signal interlocking module, and an output locking module; where Through the drive unit, according to the PWM signal, drive signals are output, including: Through the voltage conversion module, the voltage of the PWM signal is converted to obtain a signal with a set voltage; Through the bridge arm signal interlocking module, based on the signal with the set voltage, the upper and lower bridge arms of the IGBT drive board of the frequency converter are interlocked and then the drive signals are output; Through the output locking module, before the frequency converter works, the drive signals are locked to prohibit the IGBT drive board of the frequency converter from starting based on the drive signals.

14. The control method of the main control board of the frequency converter according to claim 11, characterized in that, It further includes: The control unit is further configured to, when the drive unit includes an output locking module, before the frequency converter works, cause the output locking module to prohibit the output of the drive signals, and after outputting a PWM signal with a set frequency and / or a set duty cycle, determine whether the frequency converter has a drive fault based on one or more of the detection signals among the n drive signals corresponding to the n PWM signals, so that the output locking module is allowed to output the drive signals only when the frequency converter does not have a drive fault, to control the frequency converter to drive and work; And, after the frequency converter works, determine whether the frequency converter has a drive fault based on one or more of the detection signals among the n drive signals corresponding to the n PWM signals.

15. The control method of the main control board of the frequency converter according to any one of claims 11 to 14, characterized in that, Through the control unit, determining whether the frequency converter has a drive fault based on one or more of the detection signals among the n drive signals corresponding to the n PWM signals includes: For one or more of the detection signals among the n drive signals, using the capture module of the control unit to capture one or more of the detection signals among the n drive signals; If the capture module can capture one or more of the detection signals, it is determined that among the n drive units of the frequency converter, one or more of the drive units corresponding to one or more of the detection signals do not have a drive fault, and the control of the frequency converter continues to work; If the capture module cannot capture one or more of the detection signals, it is determined that among the n drive units of the frequency converter, one or more of the drive units corresponding to one or more of the detection signals have a drive fault, and the position where the frequency converter has a drive fault is determined.

16. The control method of the main control board of the frequency converter according to claim 15, wherein, Through the control unit, determining the position where the frequency converter has a drive fault includes: Determining whether a signal with a set voltage level is captured; If the signal with the set voltage level is captured, it is determined that at least some of the n drive units have a fault; If the signal with the set voltage level is not captured, a self-check signal is initiated to detect whether the detection unit has a fault according to the self-check signal.

17. The control method of the main control board of the frequency converter according to claim 16, characterized in that, Through a control unit, according to the detection signal, detecting whether a fault occurs in the detection unit, including: Sending the self-check signal to the detection unit and determining whether the capture module of the control unit captures the self-check signal; In the case where the detection unit includes a signal feedback module and a selection module, if the capture module captures the self-check signal, it is determined that the signal feedback module fails; if the capture module does not capture the self-check signal, it is determined that the selection module fails.

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