Power supply abnormity detection circuit and frequency converter circuit

Abstract

The utility model provides a power supply abnormity detection circuit and a frequency converter circuit, and the circuit comprises a current detection module which is connected in series in a starting circuit of a frequency converter auxiliary power supply, and is used for detecting whether the current in the starting circuit is normal or not; the detection conversion module is connected with the current detection module and is used for converting whether the current in the starting circuit is normal or not into a corresponding level signal; when the level signal is a first level signal, the AC power supply input by the frequency converter is normal; and when the level signal is a second level signal, the AC power supply input by the frequency converter is abnormal. The starting circuit of the auxiliary power supply is used for detecting the input alternating current power supply of the frequency converter, so that the frequency converter is protected by using a simple circuit, the cost is low, and a good protection effect on the frequency converter is achieved.

Description

Technical Field

[0001] This application belongs to the technical field of frequency converter design, and relates to a detection circuit, in particular to a power supply abnormality detection circuit and a frequency converter circuit. Background Art

[0002] With the development of industrial automation, frequency converters are becoming more and more widely used in industry. As a device that converts electrical energy into a controllable AC power supply, a frequency converter can adjust and control the motor speed, improve production efficiency and reduce energy consumption. However, during the operation of the frequency converter, the input voltage of the frequency converter may change abnormally due to various reasons such as unstable power grid quality and power grid voltage fluctuations, which may affect the normal operation of the frequency converter or even damage the frequency converter.

[0003] The input voltage abnormality detection circuit is a very important part of the frequency converter circuit. Its main function is to interrupt the operation of the frequency converter to prevent equipment damage when the input voltage of the frequency converter is abnormal. Most of the existing frequency converter input voltage detection circuits are used to detect the phase loss of the frequency converter input. They cannot detect the situation where the AC power supply input to the frequency converter is too low or disconnected. When the AC power supply input to the frequency converter is too low, the frequency converter will restart, which may cause component damage and even equipment failure or damage in severe cases, resulting in economic losses. Summary of the Invention

[0004] This application provides a power supply abnormality detection circuit and a frequency converter circuit, which are used to solve the problem of detecting abnormal AC power supply input to the frequency converter through a simple circuit structure.

[0005] In a first aspect, this application provides a power supply abnormality detection circuit. The circuit includes: a current detection module, which is connected in series in the startup circuit of the auxiliary power supply of the frequency converter to detect whether the current in the startup circuit is normal; a detection conversion module, which is connected to the current detection module and converts whether the current in the startup circuit is normal into a corresponding level signal; when the level signal is a first level signal, it indicates that the AC power supply input to the frequency converter is normal; when the level signal is a second level signal, it indicates that the AC power supply input to the frequency converter is abnormal.

[0006] In an implementation manner of the first aspect, the current detection module includes an optocoupler; the input end of the optocoupler is connected in series in the startup circuit of the auxiliary power supply of the frequency converter, and the output end of the optocoupler is connected to the detection conversion module.

[0007] In an implementation of the first aspect, the detection and conversion module includes a first resistor, a second resistor, and a triode; one end of the first resistor and one end of the second resistor are both connected to the input voltage, the other end of the first resistor is connected to the collector of the triode, and the other end of the second resistor is connected to the base of the triode; the emitter of the triode is connected to the ground.

[0008] In an implementation of the first aspect, the circuit further includes: a control module; the control module is connected to the detection and conversion module and receives the level signal output by the detection and conversion module.

[0009] In an implementation of the first aspect, a series resistor is included in the series path of the current detection module; the series resistor is used to generate the current in the startup circuit detected by the current detection module.

[0010] In a second aspect, the present application provides an inverter circuit, and the inverter circuit includes: a power supply abnormality detection circuit; the power supply abnormality detection circuit includes a current detection module and a detection and conversion module; the current detection module is connected in series in the startup circuit of the inverter auxiliary power supply to detect whether the current in the startup circuit is normal; the detection and conversion module is connected to the current detection module and converts whether the current in the startup circuit is normal into a corresponding level signal; when the level signal is a first level signal, it indicates that the AC power supply input to the inverter is normal; when the level signal is a second level signal, it indicates that the AC power supply input to the inverter is abnormal.

[0011] In an implementation of the second aspect, the current detection module includes an optocoupler; the input end of the optocoupler is connected in series in the startup circuit of the inverter auxiliary power supply, and the output end of the optocoupler is connected to the detection and conversion module.

[0012] In an implementation of the second aspect, the detection and conversion module includes a first resistor, a second resistor, and a triode; one end of the first resistor and one end of the second resistor are both connected to the input voltage, the other end of the first resistor is connected to the collector of the triode, and the other end of the second resistor is connected to the base of the triode; the emitter of the triode is connected to the ground.

[0013] In an implementation of the second aspect, the circuit further includes: a control module; the control module is connected to the detection and conversion module and receives the level signal output by the detection and conversion module.

[0014] In an implementation of the second aspect, a series resistor is included in the series path of the current detection module; the series resistor is used to generate the current in the startup circuit detected by the current detection module.

[0015] As described above, the power supply abnormality detection circuit and the frequency converter circuit described in the present application have the following beneficial effects:

[0016] The structure of the power supply abnormality detection circuit of the present application uses the auxiliary power supply startup circuit of the frequency converter to detect the input AC power supply of the frequency converter, saving costs, realizing the protection of the frequency converter with a simple circuit structure, and the detection circuit is reliable and not prone to failure, and the components are convenient for circuit board drawing.

[0017] The present application uses the auxiliary power supply startup circuit of the frequency converter to detect the abnormality of the input AC power supply of the frequency converter. Through the circuit structure and the circuit environment provided by the hardware circuit of the power supply abnormality detection circuit and the frequency converter circuit of the present application, it is possible to make a judgment when the input AC power supply voltage of the frequency converter is too low or the power is cut off, report an error, and interrupt the operation of the frequency converter, avoiding forced restart of the frequency converter due to too low voltage, and preventing damage to the frequency converter components or frequency converter equipment failure or even damage caused by forced restart. Therefore, it has a good protection effect on the frequency converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It shows a schematic connection diagram of the structure of the power supply abnormality detection circuit described in the embodiment of the present application.

[0019] Figure 2 It shows a circuit diagram of the current detection module of the power supply abnormality detection circuit described in the embodiment of the present application.

[0020] Figure 3 It shows a circuit diagram of the detection conversion module of the power supply abnormality detection circuit described in the embodiment of the present application.

[0021] Figure 4 It shows another schematic connection diagram of the structure of the power supply abnormality detection circuit described in the embodiment of the present application.

[0022] Figure 5 It shows a schematic connection diagram of the structure of the frequency converter circuit described in the embodiment of the present application.

[0023] Figure 6 It shows a circuit structure diagram of the frequency converter circuit described in the embodiment of the present application.

[0024] Description of Component Labels

[0025] 1 Power supply abnormality detection circuit

[0026] 11 Current detection module

[0027] 12 Detection conversion module

[0028] 13 Control module DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following specific examples illustrate the implementation manners of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific implementation manners. All details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0030] It should be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of the present application. Therefore, only the components related to the present application are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0031] Next, the technical solutions in the embodiments of the present application will be described in detail with reference to the accompanying drawings in the embodiments of the present application.

[0032] Please refer to Figure 1 , which shows a schematic structural connection diagram of the power supply abnormality detection circuit described in the embodiment of the present application. As Figure 1 shown, according to the deficiencies of the current AC voltage detection method for the inverter input, the embodiment of the present application provides a power supply abnormality detection circuit 1, including: a current detection module 11 and a detection conversion module 12.

[0033] The current detection module 11 is connected in series in the startup circuit of the inverter auxiliary power supply to detect whether the current in the startup circuit is normal;

[0034] The detection conversion module 12 is connected to the current detection module 11 to convert whether the current in the startup circuit is normal into a corresponding level signal; when the level signal is a first level signal, it indicates that the AC power supply input to the inverter is normal; when the level signal is a second level signal, it indicates that the AC power supply input to the inverter is abnormal.

[0035] In one embodiment, the current detection module includes an optocoupler.

[0036] The input end of the optocoupler is connected in series in the startup circuit of the inverter auxiliary power supply, and the output end of the optocoupler is connected to the detection conversion module.

[0037] Please refer to Figure 2 , which shows a circuit diagram of the current detection module of the power supply abnormality detection circuit described in the embodiment of the present application. As Figure 2As shown, the current detection module 11 includes an optocoupler. The input end of the optocoupler is connected in series to the startup circuit of the inverter auxiliary power supply, and the output end of the optocoupler is connected to the detection conversion module 12.

[0038] Specifically, the current input end (the light-emitting diode side) of the optocoupler is connected in series to the startup circuit of the inverter auxiliary power supply. The output collector of the optocoupler is connected to the detection conversion module 12, and the output emitter of the optocoupler is grounded.

[0039] In practical applications, the anode of the input end of the optocoupler is connected to the positive pole of the auxiliary power supply startup circuit through the copper clad wire of the PCB (Printed Circuit Board), and the negative pole is connected to the startup resistor through the copper clad wire of the PCB. The optocoupler and the startup resistor are connected in series to the auxiliary power supply startup circuit to detect the current abnormality in the auxiliary power supply startup circuit caused by too low or power-off of the input AC supply voltage of the inverter.

[0040] In one embodiment, the detection conversion module includes a first resistor, a second resistor, and a triode.

[0041] One end of the first resistor and one end of the second resistor are both connected to the input voltage. The other end of the first resistor is connected to the collector of the triode, and the other end of the second resistor is connected to the base of the triode; the emitter of the triode is connected to the ground.

[0042] Please refer to Figure 3 , which shows the circuit diagram of the detection conversion module of the power supply abnormality detection circuit described in the embodiment of the present application. As Figure 3 shown, the detection conversion module 12 includes a first resistor R1, a second resistor R2, and a triode. One end of the first resistor R1 and one end of the second resistor R2 are both connected to the input voltage (5V power supply). The other end of the first resistor R1 is connected to the collector of the triode, and the other end of the second resistor R2 is connected to the base of the triode; the emitter of the triode is connected to the ground.

[0043] Specifically, in the detection conversion module 12, the emitter of the triode is grounded, and the collector of the triode outputs a level signal. Pull-up resistors of 5V are respectively connected to the base and collector of the triode, that is, the first resistor R1 and the second resistor R2.

[0044] In practical applications, the base of the triode is connected to the collector of the output end of the optocoupler through the copper clad wire of the PCB. The base and collector of the triode are respectively connected to the pull-up resistors R1 and R2 through the copper clad wire of the PCB. The other ends of the pull-up resistors R1 and R2 are connected to the 5V power supply on the PCB through the copper clad wire. The emitter of the output end of the optocoupler and the emitter of the triode are grounded.

[0045] In one embodiment, the circuit further includes: a control module.

[0046] The control module is connected to the detection conversion module and receives the level signal output by the detection conversion module.

[0047] Please refer to Figure 4 , which shows another schematic diagram of the structural connection of the power supply abnormality detection circuit described in the embodiment of the present application. As Figure 4 shown, the circuit 1 includes: a current detection module 11, a detection conversion module 12, and a control module 13. The current detection module 11 is connected in series in the startup circuit of the auxiliary power supply of the frequency converter to detect whether the current in the startup circuit is normal; the detection conversion module 12 is connected to the current detection module 11 to convert whether the current in the startup circuit is normal into a corresponding level signal; when the level signal is a first level signal, it indicates that the AC power supply input to the frequency converter is normal; when the level signal is a second level signal, it indicates that the AC power supply input to the frequency converter is abnormal. The control module 13 is connected to the detection conversion module 12 and receives the level signal output by the detection conversion module 12.

[0048] Specifically, the control module 13 includes a control chip, and the collector of the triode in the detection conversion module 12 is connected to the pin of the control chip. When the AC voltage input to the frequency converter is too small or the power is cut off, the current in the startup circuit is too small, the output of the optocoupler is cut off, the base of the triode is pulled high to 5V by the pull-up resistor, that is, the second resistor R2, the triode conducts, and the voltage between the collector of the triode and the control chip changes. The control chip can perform abnormal processing on the AC power supply input to the frequency converter. For example, the control chip can stop the operation of the frequency converter and report an error. The level signal refers to the voltage signal for the collector of the triode to send high and low levels to the control chip, and the control chip can determine whether the AC power supply input to the frequency converter is abnormal.

[0049] In one embodiment, a series resistor is included in the series path of the current detection module; the series resistor is used to generate the current in the startup circuit detected by the current detection module.

[0050] In practical applications, the working process of the abnormal detection circuit for the AC power supply input to the frequency converter is as follows:

[0051] When the AC power supply input to the frequency converter is normal, the current I in the auxiliary power supply startup circuit is sufficient to enable the optocoupler to work properly. The output terminal of the optocoupler conducts, and the voltage of the collector of the output terminal of the optocoupler and the base of the triode is pulled low by the ground of the emitter of the output terminal of the optocoupler. The triode is in the cut-off state, the collector of the triode is disconnected from the ground, and the collector of the triode is pulled high to a high level (the first level signal) by the pull-up resistor R1. The collector of the triode sends a high-level signal to the pin of the control chip, and the control chip determines that the AC power supply input to the frequency converter is normal.

[0052] When the AC power supply voltage input to the frequency converter is too low or the power is cut off, the current I in the auxiliary power supply startup circuit is too low, and the optocoupler cannot work properly. The output of the optocoupler is disconnected, and the voltage of the collector of the output terminal and the base of the triode is pulled high by the pull-up resistor R2. At this time, the base voltage of the triode is higher than the emitter voltage, and the triode works in the saturation state. The collector voltage of the triode is pulled low, and the collector of the triode sends a low-level signal (the second level signal) to the control chip. The control chip determines that the AC power supply input to the frequency converter is abnormal, and the control chip stops the operation of the frequency converter and reports an error.

[0053] It should be noted that the first level signal being a high-level signal and the second level signal being a low-level signal are only one implementation manner of the level signal transformation in this application. In addition, when the logical architecture between the various modules of the circuit in this application remains unchanged and the circuit components are adjusted adaptively, the circuit structure scheme in which the first level signal is a low-level signal and the second level signal is a high-level signal is also within the protection scope of this application.

[0054] Please refer to Figure 5 , which shows the structural connection schematic diagram of the frequency converter circuit described in the embodiment of this application. As Figure 5 shown, the embodiment of this application provides a frequency converter circuit, and the frequency converter circuit includes: a power supply abnormality detection circuit 1; the power supply abnormality detection circuit 1 includes a current detection module 11 and a detection conversion module 12.

[0055] The current detection module 11 is connected in series in the startup circuit of the auxiliary power supply of the frequency converter to detect whether the current in the startup circuit is normal.

[0056] The detection conversion module 12 is connected to the current detection module 11 to convert whether the current in the startup circuit is normal into a corresponding level signal; when the level signal is the first level signal, it indicates that the AC power supply input to the frequency converter is normal; when the level signal is the second level signal, it indicates that the AC power supply input to the frequency converter is abnormal.

[0057] In one embodiment, the current detection module includes an optocoupler.

[0058] The input end of the optocoupler is connected in series to the startup circuit of the auxiliary power supply of the frequency converter, and the output end of the optocoupler is connected to the detection and conversion module.

[0059] As Figure 2 shown, the current detection module 11 includes an optocoupler. The input end of the optocoupler is connected in series to the startup circuit of the auxiliary power supply of the frequency converter, and the output end of the optocoupler is connected to the detection and conversion module 12.

[0060] In one embodiment, the detection and conversion module includes a first resistor, a second resistor, and a triode.

[0061] One end of the first resistor and one end of the second resistor are both connected to the input voltage. The other end of the first resistor is connected to the collector of the triode, and the other end of the second resistor is connected to the base of the triode; the emitter of the triode is connected to the ground.

[0062] As Figure 3 shown, the detection and conversion module 12 includes a first resistor R1, a second resistor R2, and a triode. One end of the first resistor R1 and one end of the second resistor R2 are both connected to the input voltage (5V power supply). The other end of the first resistor R1 is connected to the collector of the triode, and the other end of the second resistor R2 is connected to the base of the triode; the emitter of the triode is connected to the ground.

[0063] In one embodiment, the circuit further includes: a control module.

[0064] The control module is connected to the detection and conversion module and receives the level signal output by the detection and conversion module.

[0065] As Figure 4 shown, the circuit 1 includes: a current detection module 11, a detection and conversion module 12, and a control module 13. The current detection module 11 is connected in series to the startup circuit of the auxiliary power supply of the frequency converter to detect whether the current in the startup circuit is normal; the detection and conversion module 12 is connected to the current detection module 11 to convert whether the current in the startup circuit is normal into a corresponding level signal; when the level signal is a first level signal, it indicates that the AC power supply input to the frequency converter is normal; when the level signal is a second level signal, it indicates that the AC power supply input to the frequency converter is abnormal. The control module 13 is connected to the detection and conversion module 12 and receives the level signal output by the detection and conversion module 12.

[0066] In one embodiment, a series resistor is included in the series path of the current detection module; the series resistor is used to generate the current in the startup circuit detected by the current detection module.

[0067] Please refer toFigure 6 , which shows the circuit structure diagram of the frequency converter circuit described in the embodiments of the present application. As Figure 6 shown, the anode of the input end of the optocoupler is connected to the positive pole of the auxiliary power supply startup circuit through the copper clad wire of the PCB (printed circuit board), and the negative pole is connected to the startup resistor R3 through the copper clad wire of the PCB. The optocoupler is connected in series with the startup resistors R3, R4... Rn in the auxiliary power supply startup circuit to detect the abnormal current in the auxiliary power supply startup circuit caused by too low or power-off of the input AC power supply voltage of the frequency converter. Among them, the current I of the auxiliary power supply startup circuit = input voltage V / (R3 + R4 +... + Rn).

[0068] Combined with Figure 6 , in the frequency converter circuit, the working process of the abnormal detection circuit of the input AC power supply is as follows:

[0069] When the input AC power supply of the frequency converter is normal, the current I of the auxiliary power supply startup circuit is sufficient to make the optocoupler work normally. The output end of the optocoupler is turned on, and the voltage of the collector of the output end of the optocoupler and the base of the triode is pulled low by the ground of the emitter of the output end of the optocoupler. The triode is in the cut-off state, the collector of the triode is disconnected from the ground, and the collector of the triode is pulled high to a high level by the pull-up resistor R1. The collector of the triode sends a high-level signal to the pin of the control chip, and the control chip judges that the input AC power supply of the frequency converter is normal.

[0070] When the input AC power supply voltage of the frequency converter is too low or the power is off, the current I in the auxiliary power supply startup circuit is too low, the optocoupler cannot work normally, the output of the optocoupler is disconnected, and the voltage of the collector of the output end and the base of the triode is pulled high by the pull-up resistor R2. At this time, the base voltage of the triode is higher than the emitter voltage, the triode works in the saturation state, the collector voltage of the triode is pulled low, and the collector of the triode sends a low-level signal to the control chip. The control chip judges that the input AC power supply of the frequency converter is abnormal, and the control chip stops the operation of the frequency converter and reports an error.

[0071] In several embodiments provided by the present application, it should be understood that the disclosed circuit can be implemented in other ways. For example, the circuit embodiments described above are only illustrative. For example, the division of modules / units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple modules or units can be combined or integrated into another system, or some features can be ignored or not executed. Another point, the displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces, and the indirect coupling or communication connection of devices or modules or units can be in electrical, mechanical or other forms.

[0072] The module / unit described as a separate component may or may not be physically separated. The component shown as a module / unit may or may not be a physical module, that is, it may be located in one place or distributed across multiple network units. Some or all of the modules / units can be selected according to actual needs to achieve the objectives of the embodiments of the present application. For example, in each embodiment of the present application, each functional module / unit can be integrated into a processing module, or each module / unit can exist physically alone, or two or more modules / units can be integrated into one module / unit.

[0073] The above embodiments are only illustrative of the principles and effects of the present application and are not intended to limit the present application. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present application should still be covered by the claims of the present application.

Claims

1. A power supply abnormal detection circuit, characterized in that, The circuit includes: a current detection module, which is connected in series in the startup circuit of the auxiliary power supply of the frequency converter to detect whether the current in the startup circuit is normal; a detection conversion module, connected to the current detection module, which converts whether the current in the startup circuit is normal into a corresponding level signal; when the level signal is a first level signal, it indicates that the AC power supply input to the frequency converter is normal; when the level signal is a second level signal, it indicates that the AC power supply input to the frequency converter is abnormal.

2. The circuit according to claim 1, wherein, The current detection module includes an optocoupler; the input end of the optocoupler is connected in series in the startup circuit of the auxiliary power supply of the frequency converter, and the output end of the optocoupler is connected to the detection conversion module.

3. The circuit according to claim 1, wherein The detection conversion module includes a first resistor, a second resistor and a triode; one end of the first resistor and one end of the second resistor are both connected to the input voltage, the other end of the first resistor is connected to the collector of the triode, and the other end of the second resistor is connected to the base of the triode; the emitter of the triode is connected to the ground.

4. The circuit according to claim 1, characterized in that, The circuit further includes: a control module; the control module is connected to the detection conversion module and receives the level signal output by the detection conversion module.

5. The circuit according to claim 1, wherein A series resistor is included in the series path of the current detection module; the series resistor is used to generate the current in the startup circuit detected by the current detection module.

6. A frequency converter circuit, characterized in that, The frequency converter circuit includes: a power supply abnormality detection circuit; the power supply abnormality detection circuit includes a current detection module and a detection conversion module; the current detection module is connected in series in the startup circuit of the auxiliary power supply of the frequency converter to detect whether the current in the startup circuit is normal; the detection conversion module is connected to the current detection module, which converts whether the current in the startup circuit is normal into a corresponding level signal; when the level signal is a first level signal, it indicates that the AC power supply input to the frequency converter is normal; when the level signal is a second level signal, it indicates that the AC power supply input to the frequency converter is abnormal.

7. The circuit according to claim 6, characterized in that, The current detection module includes an optocoupler; the input end of the optocoupler is connected in series in the startup circuit of the auxiliary power supply of the frequency converter, and the output end of the optocoupler is connected to the detection conversion module.

8. The circuit according to claim 6, wherein The detection conversion module includes a first resistor, a second resistor and a triode; one end of the first resistor and one end of the second resistor are both connected to the input voltage, the other end of the first resistor is connected to the collector of the triode, and the other end of the second resistor is connected to the base of the triode; the emitter of the triode is connected to the ground.

9. The circuit according to claim 6, characterized in that, The circuit further includes: a control module; the control module is connected to the detection conversion module and receives the level signal output by the detection conversion module.

10. The circuit according to claim 6, wherein A series resistor is included in the series path of the current detection module; the series resistor is used to generate the current in the startup circuit detected by the current detection module.

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