Anti-electromagnetic interference circuit and switching power supply device

Abstract

The embodiment of the application provides an anti-electromagnetic interference circuit and a switching power supply device, and the circuit arranged between a plurality of power lines of the switching power supply device comprises: a capacitor, a switching module corresponding to the capacitor, and a control module; the capacitor and the switching module are connected in series between the plurality of power lines; and the control module is used for controlling the switching module to be turned on when detecting that a circuit state is normal according to a working parameter of the capacitor, and controlling the switching module to be turned off when detecting that the circuit state is abnormal. According to the scheme, the working state of the capacitor is monitored by the control module, and the switching module is turned off in time when the capacitor works abnormally, so that the cost of anti-electromagnetic interference is reduced under the premise that a safety capacitor is not used but safety can be ensured.

Description

Technical Field

[0001] This application relates to the field of electromagnetic interference suppression technology, and in particular to an electromagnetic interference suppression circuit and a switching power supply device. Background Technology

[0002] Switching power supplies are key components in electronic devices, used to convert voltage and current to meet the needs of different circuits. The switching devices in switching power supplies typically generate conducted electromagnetic interference (EMI) when turning on and off, which includes differential-mode interference and common-mode interference.

[0003] In existing electromagnetic interference (EMI) mitigation solutions, safety capacitors are used as differential-mode capacitors between the power lines of AC switching power supplies to eliminate differential-mode interference. However, these safety capacitors are expensive. Therefore, the current challenge is to reduce the cost of EMI mitigation. Summary of the Invention

[0004] This application provides an electromagnetic interference suppression circuit and a switching power supply device to reduce the cost of electromagnetic interference suppression.

[0005] In a first aspect, embodiments of this application provide an anti-electromagnetic interference circuit disposed between multiple power lines of a switching power supply device; the circuit includes: a capacitor, a switching module corresponding to the capacitor, and a control module; the capacitor and the switching module are connected in series and connected between multiple power lines; the control terminal of the switching module is connected to the control module; the control module is used to control the switching module to conduct when no abnormality is detected in the circuit state, and to control the switching module to disconnect when an abnormality is detected in the circuit state, based on the operating parameters of the capacitor.

[0006] In one possible implementation, the electromagnetic interference suppression circuit further includes a first voltage detection device and a plurality of first current detection devices; the two ends of the first voltage detection device are respectively connected to a plurality of power lines for detecting the voltage difference between the plurality of power lines; the plurality of first current detection devices are respectively disposed on the plurality of power lines for detecting the current of the power line in which they are located; the control module is connected to the first voltage detection device and the plurality of first current detection devices, and the control module is used to calculate the power parameters of the capacitor based on the detection results of the first voltage detection device and the plurality of first current detection devices, and control the switching module based on the power parameters.

[0007] In one possible implementation, the electromagnetic interference suppression circuit further includes: a second current detection device; the second current detection device is connected in series with the capacitor and the switching module to detect the current flowing through the capacitor; and a control module connected to the second current detection device to control the switching module based on the detection result of the second current detection device.

[0008] In one possible implementation, the electromagnetic interference suppression circuit further includes: a temperature sensor; the temperature sensor is used to acquire the temperature of the capacitor; the temperature sensor is connected to a control module, and the control module is used to control the switching module according to the temperature of the capacitor.

[0009] In one possible implementation, the switching module includes a transistor, the control terminal of which is connected to the control module.

[0010] Secondly, embodiments of this application provide a switching power supply device, wherein the above-mentioned anti-electromagnetic interference circuit is provided between the multiple power lines of the switching power supply device.

[0011] In one possible implementation, the switching power supply device is a three-phase power supply, and the switching power supply module is connected to the input power supply through a first power line, a second power line, and a third power line.

[0012] In one possible implementation, an anti-electromagnetic interference circuit is provided between any two of the first power line, second power line, and third power line.

[0013] In one possible implementation, each of the first power line, the second power line, and the third power line is provided with an electromagnetic interference suppression circuit between it and the common connection line.

[0014] In one possible implementation, the switching power supply device further includes: a first resistor, a second resistor, and a third resistor with the same resistance value; an electromagnetic interference suppression circuit between each power line and a common connection line, which is connected to a first common point; one end of the first resistor, one end of the second resistor, and one end of the third resistor are respectively connected to the first power line, the second power line, and the third power line, and the other ends of the first resistor, the second resistor, and the third resistor are connected to a second common point; and a control module for the electromagnetic interference suppression circuit is used to control the switching module of the electromagnetic interference suppression circuit according to the voltage difference between the first common point and the second common point.

[0015] In one possible implementation, the switching power supply device further includes a second voltage detection device; the second voltage detection device is connected to the first common point, the second common point, and the control module; the second voltage detection device is used to detect the voltage difference between the first common point and the second common point.

[0016] In one possible implementation, the second voltage detection device includes: a fourth resistor and a fifth resistor; one end of the fourth resistor is connected to a first common point, the other end of the fourth resistor is connected to one end of the fifth resistor, and the other end of the fifth resistor is connected to a second common point; a control module is connected to both ends of the fifth resistor and is used to control the switching module of the electromagnetic interference suppression circuit according to the voltage difference between the two ends of the fifth resistor.

[0017] The electromagnetic interference suppression circuit and switching power supply device provided in this application include a circuit disposed between multiple power lines of the switching power supply device, comprising: a capacitor, a corresponding switching module, and a control module; the capacitor and the switching module are connected in series between the multiple power lines; the control module is used to control the switching module to conduct when no abnormality is detected in the circuit state, and to control the switching module to disconnect when an abnormality is detected in the circuit state, based on the operating parameters of the capacitor. The solution of this application monitors the operating state of the capacitor through the control module and promptly disconnects the switching module when the capacitor malfunctions, thereby reducing the cost of electromagnetic interference suppression without using safety capacitors while still ensuring safety. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0019] Figure 1 The electromagnetic interference suppression scheme provided in this application;

[0020] Figure 2 A schematic diagram of the electromagnetic interference suppression circuit provided in this application;

[0021] Figure 3 A schematic diagram of the electromagnetic interference suppression circuit provided in this application;

[0022] Figure 4 A schematic diagram of the electromagnetic interference suppression circuit provided in this application;

[0023] Figure 5 A schematic diagram of the electromagnetic interference suppression circuit provided in this application;

[0024] Figure 6 A schematic diagram of the connection structure between the switching power supply device and the electromagnetic interference suppression circuit provided in this application;

[0025] Figure 7 A schematic diagram of the connection structure between the switching power supply device and the electromagnetic interference suppression circuit provided in this application;

[0026] Figure 8 A schematic diagram of the connection structure between the switching power supply device and the electromagnetic interference suppression circuit provided in this application;

[0027] Figure 9 A schematic diagram of the connection structure between the switching power supply device and the electromagnetic interference suppression circuit provided in this application;

[0028] Figure 10 A schematic diagram of the connection structure between the switching power supply device and the electromagnetic interference suppression circuit provided in this application;

[0029] Figure 11This is a schematic diagram of the connection structure between the switching power supply device and the electromagnetic interference suppression circuit provided in this application.

[0030] Explanation of reference numerals in the attached drawings: Switching power supply device 10, anti-electromagnetic interference circuit 20, first resistor 11, second resistor 12, third resistor 13, second voltage detection device 14, capacitor 21, switching module 22, control module 23, first voltage detection device 24, first current detection device 25, second current detection device 26, temperature sensor 27, fourth resistor 141, fifth resistor 142.

[0031] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0032] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0033] A switching power supply is a highly efficient power conversion device that converts input voltage into the required output voltage through rapid switching to meet the power needs of various electronic devices. In switching power supplies, conducted electromagnetic interference (EMI) is generated when the switching devices are turned on and off, primarily due to rapid changes in current and voltage. Conducted EMI can be divided into differential-mode interference and common-mode interference: differential-mode interference refers to noise signals transmitted between power lines, usually caused by rapid changes in current; common-mode interference refers to noise signals that occur simultaneously between the power line and ground, usually caused by electromagnetic radiation or circuit asymmetry.

[0034] Related technologies provide, for example Figure 1The figure illustrates an electromagnetic interference (EMI) suppression scheme for a three-phase switching power supply. It employs a three-phase common-mode inductor to eliminate common-mode interference, three differential-mode inductors corresponding one-to-one with each phase line to eliminate differential-mode interference, and three differential-mode capacitors connected between two phase lines to eliminate differential-mode interference. The differential-mode inductors and capacitors can be used individually or simultaneously. The differential-mode capacitors typically use safety capacitors such as X-type capacitors. X-type capacitors have good voltage surge resistance and will not cause short circuits between phase lines in the event of a fault, thus avoiding safety issues such as fires and high temperatures caused by short circuits. However, these capacitors are usually made of high-quality dielectric materials and use complex processes, resulting in high costs and increasing the overall cost of the switching power supply.

[0035] The technical content provided in this application aims to solve the aforementioned technical problems in related technologies. The electromagnetic interference suppression circuit and switching power supply device provided in this application, disposed between multiple power lines of the switching power supply device, includes: a capacitor, a corresponding switching module, and a control module; the capacitor and the switching module are connected in series between the multiple power lines; the control module is used to control the switching module to conduct when no abnormality is detected in the circuit state, and to control the switching module to disconnect when an abnormality is detected in the circuit state, based on the capacitor's operating parameters. The solution of this application monitors the operating state of the capacitor through the control module and promptly disconnects the switching module when the capacitor malfunctions, thereby reducing the cost of electromagnetic interference suppression without using safety capacitors while still ensuring safety.

[0036] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0037] Example 1

[0038] Figure 2 This is a schematic diagram of the electromagnetic interference suppression circuit 20 provided in this application. Figure 2 As shown, this circuit is arranged between multiple power lines of the switching power supply device 10. The circuit method is as follows:

[0039] Capacitor 21, switching module 22 corresponding to capacitor 21, and control module 23;

[0040] Capacitor 21 and switching module 22 are connected in series, and the series connection is between multiple power lines;

[0041] The control terminal of the switching module 22 is connected to the control module 23. The control module 23 is used to control the switching module 22 to turn on when no abnormality is detected in the circuit state, and to control the switching module 22 to turn off when an abnormality is detected in the circuit state, based on the operating parameters of the capacitor 21.

[0042] In this example, the switching power supply device 10 can be a DC switching power supply device 10 or an AC switching power supply device 10, such as AC / DC, DC / DC, or DC / AC. Specifically, different power lines correspond to different types of input power supplies for the switching power supply device 10. For example, a three-phase AC input corresponds to three phase lines, a single-phase AC input corresponds to one phase line and one neutral line, and a DC input corresponds to a positive line and a negative line. On one hand, for the three phase lines (L1, L2, L3) in a three-phase AC input, corresponding electromagnetic interference suppression circuits 20 are provided between L1 and L2, between L2 and L3, and between L1 and L3. Optionally, the three electromagnetic interference suppression circuits 20 corresponding to the three-phase AC input can be arranged between multiple power lines in a delta or Y connection. On the other hand, electromagnetic interference suppression circuits 20 are provided for the phase line and neutral line in a single-phase AC input. In this example, the electromagnetic interference suppression circuit 20 connects capacitor 21 and switching module 22 in series between multiple power lines. Switching module 22 can disconnect capacitor 21 from the power lines. In practical applications, switching module 22 can be a transistor, digital switch, or analog switch—a device capable of turning circuits on and off.

[0043] The control terminal of the switch is connected to the control module 23. The control module 23 controls the switching module 22 to turn on when no abnormality is detected in the circuit, and controls the switching module 22 to turn off when an abnormality is detected, based on the operating parameters of the capacitor 21. In practical applications, the control module 23 can be a microcontroller, microprocessor, or digital signal processor. The operating parameters of the capacitor 21 can be its external characteristics, such as temperature and humidity, or circuit parameters, such as voltage, current, power, or noise figure. In practical applications, abnormalities in the circuit state can be surge breakdown due to high voltage impact or power frequency overvoltage breakdown, or short circuit of the capacitor 21 due to aging or deterioration, or overcurrent. The solution in this example improves circuit safety by monitoring the capacitor 21, achieving compliance with relevant safety standards without using the expensive safety-certified capacitor 21. In practical applications, capacitors 21 with different electrical characteristics or specifications can be selected as differential mode capacitors in the electromagnetic interference suppression circuit 20 based on requirements, such as metallized polypropylene film capacitors with higher ripple current tolerance, or ceramic capacitors with better high-frequency noise cancellation capabilities.

[0044] For example, after the control module 23 controls the switching module 22 to disconnect, the control module 23 can remind relevant personnel to perform maintenance through communication or an abnormal indicator light. Optionally, for the electromagnetic interference suppression circuit 20 with a backup capacitor 21, the control module 23 can also control the switching module 22 to connect the backup capacitor 21 while disconnecting the abnormal capacitor 21, so as to ensure the normal operation of the circuit.

[0045] The electromagnetic interference suppression circuit provided in this application includes a circuit disposed between multiple power lines of a switching power supply device, comprising: a capacitor, a corresponding switching module, and a control module; the capacitor and the switching module are connected in series between the multiple power lines; the control module is used to control the switching module to conduct when no abnormality is detected in the circuit state, and to control the switching module to disconnect when an abnormality is detected in the circuit state, based on the capacitor's operating parameters. The solution of this application monitors the operating state of the capacitor through the control module and promptly disconnects the switching module when the capacitor malfunctions, thereby reducing the cost of electromagnetic interference suppression without using safety capacitors while still ensuring safety.

[0046] As yet another example, Figure 3 This is a schematic diagram of the electromagnetic interference suppression circuit 20 provided in this application. Figure 3 As shown, the electromagnetic interference suppression circuit 20 also includes a first voltage detection device 24 and multiple first current detection devices 25;

[0047] The first voltage detection device 24 is connected to multiple power lines at both ends to detect the voltage difference between the multiple power lines.

[0048] Multiple first current detection devices 25 are respectively installed on multiple power lines to detect the current of the power line in which they are located.

[0049] The control module 23 is connected to the first voltage detection device 24 and multiple first current detection devices 25. The control module 23 is used to calculate the power parameters of the capacitor 21 based on the detection results of the first voltage detection device 24 and multiple first current detection devices 25, and control the switching module 22 based on the power parameters.

[0050] In this example, the voltage difference between multiple power lines detected by the first voltage detection device 24 is used as the voltage across capacitor 21, and the current in the power line detected by the first current detection device 25 is used as the input current at one end or the other end of capacitor 21. Specifically, the input power at both ends is calculated based on the voltage difference between multiple power lines, the input current at one end of capacitor 21, and the input current at the other end of capacitor 21, and the difference between the two input powers is taken as the active power of capacitor 21. In practical applications, a sudden increase in the active power of capacitor 21 may indicate a short circuit fault, or a sudden decrease in the active power of capacitor 21 may indicate an open circuit fault. Optionally, a sudden change in the active power of capacitor 21 may be caused by other types of capacitor 21 faults such as aging or poor pin contact. The solution of this application, by monitoring the power parameters of capacitor 21, can further provide reliability and safety against electromagnetic interference.

[0051] As yet another example, Figure 4 This is a schematic diagram of the electromagnetic interference suppression circuit 20 provided in this application. Figure 4 As shown, the electromagnetic interference suppression circuit 20 also includes a second current detection device 26;

[0052] The second current detection device 26 is connected in series with the capacitor 21 and the switching module 22, and is used to detect the current flowing through the capacitor 21.

[0053] The control module 23 is connected to the second current detection device 26 and is used to control the switching module 22 according to the detection result of the second current detection device 26.

[0054] This example solution does not restrict the order of series-connected electronic components. For example, the sequential connection in the electromagnetic interference suppression circuit 20 between the phase line and the neutral line of a single-phase AC input can be the phase line, the second current detection device 26, the capacitor 21, the switching module 22, and the neutral line; or the phase line, the capacitor 21, the switching module 22, the second current detection device 26, and the neutral line; or other optional series connection methods. In this example, the current parameters measured by the second current detection device 26 can be the effective current value, the instantaneous current value, and the DC bias value. By monitoring these current parameters in real time, abnormal operating conditions of the capacitor 21, such as short-circuit abnormalities or arcing abnormalities, can be detected. In practical applications, corresponding parameter threshold ranges can be set for the current parameters. When the current parameter is not within the parameter threshold, the circuit is determined to be abnormal, and the switching module 22 is controlled to disconnect. This example solution, by setting the second current detection device 26, can reduce the cost of the electromagnetic interference suppression circuit 20 while monitoring the current parameters of the capacitor 21.

[0055] As yet another example, Figure 5This is a schematic diagram of the electromagnetic interference suppression circuit 20 provided in this application. Figure 5 As shown, temperature sensor 27;

[0056] Temperature sensor 27 is used to collect the temperature of capacitor 21;

[0057] Temperature sensor 27 is connected to control module 23. Control module 23 is used to control switching module 22 according to the temperature of capacitor 21.

[0058] In this example, the temperature sensor 27 can be a thermocouple, a thermistor, or a resistance temperature sensor 27 to detect abnormally high temperatures in capacitor 21 when it fails or experiences internal arcing. In practical applications, the temperature data of capacitor 21 during normal operation can be collected as a reference value, and a warning value can be set based on this reference value. When capacitor 21 reaches the warning value, the control module 23 controls the switching module 22 to disconnect. This example solution, based on monitoring the temperature parameters of capacitor 21, can improve the safety of the electromagnetic interference suppression circuit 20.

[0059] As yet another example, switching module 22 includes a transistor, the control terminal of which is connected to control module 23.

[0060] In practical applications, transistors can be MOSFETs, NPN, PNP, or IGBTs, etc. The solution in this example uses transistors in the switching module 22 to achieve circuit switching, which improves the response speed and ease of integration of the switching module 22.

[0061] The electromagnetic interference suppression circuit provided in this embodiment includes a circuit disposed between multiple power lines of the switching power supply device, comprising: a capacitor, a corresponding switching module, and a control module; the capacitor and the switching module are connected in series between the multiple power lines; the control module is used to control the switching module to conduct when no abnormality is detected in the circuit state, and to control the switching module to disconnect when an abnormality is detected in the circuit state, based on the capacitor's operating parameters. The solution of this application monitors the operating state of the capacitor through the control module and promptly disconnects the switching module when the capacitor malfunctions, thereby reducing the cost of electromagnetic interference suppression without using safety capacitors while still ensuring safety.

[0062] Example 2

[0063] This embodiment provides a switching power supply device 10, wherein an anti-electromagnetic interference circuit 20 is provided between the multiple power lines of the switching power supply device 10.

[0064] In this example, the switching power supply device 10 can be a DC switching power supply device 10 or an AC switching power supply device 10, such as AC / DC, DC / DC, or DC / AC. Specifically, different power lines correspond to different types of input power supplies for the switching power supply device 10. For example, a three-phase AC input corresponds to three phase lines, a single-phase AC input corresponds to one phase line and one neutral line, and a DC input corresponds to a positive line and a negative line. On one hand, for the three phase lines (L1, L2, L3) in a three-phase AC input, corresponding electromagnetic interference suppression circuits 20 are provided between L1 and L2, between L2 and L3, and between L1 and L3. Optionally, the three electromagnetic interference suppression circuits 20 corresponding to the three-phase AC input can be arranged between multiple power lines in a delta or Y connection. On the other hand, electromagnetic interference suppression circuits 20 are provided for the phase line and neutral line in a single-phase AC input. In this example, the electromagnetic interference suppression circuit 20 connects capacitor 21 and switching module 22 in series between multiple power lines. Switching module 22 can disconnect capacitor 21 from the power lines. In practical applications, switching module 22 can be a transistor, digital switch, or analog switch—a device capable of turning circuits on and off.

[0065] The control terminal of the switch is connected to the control module 23. The control module 23 controls the switching module 22 to turn on when no abnormality is detected in the circuit, and controls the switching module 22 to turn off when an abnormality is detected, based on the operating parameters of the capacitor 21. In practical applications, the control module 23 can be a microcontroller, microprocessor, or digital signal processor. The operating parameters of the capacitor 21 can be its external characteristics, such as temperature and humidity, or circuit parameters, such as voltage, current, power, or noise figure. In practical applications, abnormalities in the circuit state can be surge breakdown or power frequency overvoltage breakdown caused by high voltage impact, or short circuit of the capacitor 21 caused by aging or deterioration, or overcurrent. The solution in this example improves circuit safety by monitoring the capacitor 21, achieving compliance with relevant safety standards without using expensive safety capacitors. In practical applications, capacitors with different electrical characteristics or specifications can be selected as differential-mode capacitors in the electromagnetic interference suppression circuit 20, such as metallized polypropylene film capacitors with higher ripple current tolerance, or ceramic capacitors with better high-frequency noise cancellation capabilities.

[0066] For example, after the control module 23 controls the switching module 22 to disconnect, the control module 23 can remind relevant personnel to perform maintenance through communication or an abnormal indicator light. Optionally, for the electromagnetic interference suppression circuit 20 with a backup capacitor 21, the control module 23 can also control the switching module 22 to connect the backup capacitor 21 while disconnecting the abnormal capacitor 21, so as to ensure the normal operation of the circuit.

[0067] The switching power supply device provided in this application includes a circuit disposed between multiple power lines of the switching power supply device, comprising: a capacitor, a corresponding switching module, and a control module; the capacitor and the switching module are connected in series between the multiple power lines; the control module is used to control the switching module to conduct when no abnormality is detected in the circuit state, and to control the switching module to disconnect when an abnormality is detected in the circuit state, based on the operating parameters of the capacitor. The solution of this application monitors the operating state of the capacitor through the control module and promptly disconnects the switching module when the capacitor malfunctions, thereby reducing the cost of electromagnetic interference suppression without using safety capacitors while still ensuring safety.

[0068] As another example, the switching power supply device 10 is a three-phase power supply, and the switching power supply module is connected to the input power supply through the first power line, the second power line, and the third power line.

[0069] In this example, an electromagnetic interference (EMI) suppression circuit 20 is connected between any two of the first, second, and third power lines, or an EMI suppression circuit 20 is connected between each of the three power lines and the neutral line of the three-phase power supply. In practical applications, the control modules 23 of the three EMI suppression circuits 20 corresponding to the three-phase power supply can be independent and work in cooperation with each other, or the control modules 23 can be a shared control module 23 that schedules operations. The solution in this example, by providing an EMI suppression circuit 20 for the three-phase switching power supply device 10, can improve the applicability of the EMI suppression circuit 20 solution.

[0070] As yet another example, Figure 6 This is a schematic diagram showing the connection structure between the switching power supply device 10 and the electromagnetic interference suppression circuit 20 provided in this application. Figure 6 As shown, an anti-electromagnetic interference circuit 20 is provided between any two of the first power line, the second power line, and the third power line.

[0071] In this example, an electromagnetic interference (EMI) suppression circuit 20 is placed between any two power lines. If one EMI suppression circuit 20 fails, it will not affect the others, thus improving the system's modularity. Furthermore, by customizing each EMI suppression circuit 20 according to specific needs, the flexibility of the EMI suppression circuit 20 can be increased.

[0072] As yet another example, Figure 7 This is a schematic diagram showing the connection structure between the switching power supply device 10 and the electromagnetic interference suppression circuit 20 provided in this application. Figure 7 As shown, each of the first power line, the second power line, and the third power line is provided with an anti-electromagnetic interference circuit 20 between the power line and the common connection line.

[0073] The electromagnetic interference circuit in this example uses the neutral line as a common connection line, making it suitable for circuit systems with complex or unbalanced loads requiring single-phase power. Optionally, the common connection line can be grounded to further improve system safety and voltage stability, especially under unbalanced load conditions. This example solution enhances the system's applicability to unbalanced loads, thereby improving system safety and stability.

[0074] As yet another example, Figure 8 This is a schematic diagram showing the connection structure between the switching power supply device 10 and the electromagnetic interference suppression circuit 20 provided in this application. Figure 8 As shown, the switching power supply device 10 also includes: a first resistor 11, a second resistor 12, and a third resistor 13 with the same resistance value;

[0075] The electromagnetic interference suppression circuit 20 between each power line and the common connection line is connected to the first common point;

[0076] One end of the first resistor 11, one end of the second resistor 12, and one end of the third resistor 13 are respectively connected to the first power line, the second power line, and the third power line. The other ends of the first resistor 11, the second resistor 12, and the third resistor 13 are all connected to the second common point.

[0077] The control module 23 of the electromagnetic interference suppression circuit 20 is used to control the switching module 22 of the electromagnetic interference suppression circuit 20 according to the voltage difference between the first common point and the second common point.

[0078] In this example, a three-phase balanced network can be constructed by connecting the electromagnetic interference suppression circuit 20 between each power line and the common connection line to the first common point. Simultaneously, another three-phase balanced network can be constructed by connecting the first resistor 11, the second resistor 12, and the third resistor 13 to the first, second, and third power lines, respectively, to the second common point. In practical applications, when the circuit is operating normally, the voltage difference between the two common points is zero or very small. When the capacitor 21 in the electromagnetic interference suppression circuit 20 experiences parameter shifts or failure, the three-phase balanced network corresponding to the first common point is no longer balanced, while the three-phase balanced network corresponding to the second common point remains balanced. At this point, a voltage difference will exist between the first and second common points. For example, the voltage difference can be obtained by directly testing the first and second common points, or by testing the voltage difference between the first and second common points and a third reference point, such as ground, and then further calculating the voltage difference between them. In practical applications, the abnormal capacitor 21 can be identified by performing time-domain analysis on the voltage difference, and the corresponding control module 23 can control the switching module 22 to disconnect the abnormal capacitor 21. Specifically, the above effect can be achieved by analyzing the fluctuations in the time domain of the voltage difference through a sampling circuit.

[0079] As yet another example, Figure 9 This is a schematic diagram showing the connection structure between the switching power supply device 10 and the electromagnetic interference suppression circuit 20 provided in this application. Figure 9 As shown, the switching power supply device 10 also includes: a second voltage detection device 14;

[0080] The second voltage detection device 14 is connected to the first common point, the second common point and the control module 23; the second voltage detection device 14 is used to detect the voltage difference between the first common point and the second common point.

[0081] The voltage detection device in this example can be a voltmeter, such as an analog voltmeter or a digital voltmeter, or a voltage sensor, such as a resistive voltage divider, a capacitive voltage divider, a Hall effect sensor, or a voltage relay, etc. In this example, the voltage difference between the second voltage detection device 14 and the first and second common points can be detected, allowing the control module 23 to perform control based on the voltage difference.

[0082] As yet another example, Figure 10 This is a schematic diagram showing the connection structure between the switching power supply device 10 and the electromagnetic interference suppression circuit 20 provided in this application. Figure 10 As shown, the second voltage detection device 14 also includes: a fourth resistor 141 and a fifth resistor 142;

[0083] One end of the fourth resistor 141 is connected to the first common point, and the other end of the fourth resistor 141 is connected to one end of the fifth resistor 142. The other end of the fifth resistor 142 is connected to the second common point.

[0084] The control module 23 is connected to both ends of the fifth resistor 142 and is used to control the switching module 22 of the electromagnetic interference suppression circuit 20 according to the voltage difference between the two ends of the fifth resistor 142.

[0085] In this example, a voltage divider is formed by the fourth resistor 141 and the fifth resistor 142, allowing the control module 23 to directly detect the voltage across the fifth resistor 142 to obtain the voltage difference between the first common point and the second common point. The solution in this application, where the fourth resistor 141 and the fifth resistor 142 form a voltage divider, simplifies the circuit and protects the control module 23.

[0086] As yet another example, Figure 11 This is a schematic diagram of the connection structure between the switching power supply device 10 and the electromagnetic interference suppression circuit 20 provided in this application. As shown in the figure, the electromagnetic interference suppression circuit 20 shares a control module 23. The switching module 22 in the electromagnetic interference suppression circuit 20 is a MOSFET device. The source and drain of this MOSFET device are respectively one end of capacitor 21 and the first common point. The gate of this MOSFET is connected to the shared control module 22. Simultaneously, the control module 22 is also connected to both ends of the fifth resistor 142 to obtain the voltage difference between the first common point and the second common point, and controls the conduction and disconnection of the corresponding MOSFET based on this voltage difference.

[0087] The switching power supply device provided in this application includes a circuit disposed between multiple power lines of the switching power supply device, comprising: a capacitor, a corresponding switching module, and a control module; the capacitor and the switching module are connected in series between the multiple power lines; the control module is used to control the switching module to conduct when no abnormality is detected in the circuit state, and to control the switching module to disconnect when an abnormality is detected in the circuit state, based on the operating parameters of the capacitor. The solution of this application monitors the operating state of the capacitor through the control module and promptly disconnects the switching module when the capacitor malfunctions, thereby reducing the cost of electromagnetic interference suppression without using safety capacitors while still ensuring safety.

[0088] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. An electromagnetic interference suppression circuit, characterized in that, The circuit is disposed between multiple power lines of the switching power supply device; the circuit includes: a capacitor, a switching module corresponding to the capacitor, and a control module. The capacitor and the switching module are connected in series, and the series connection is then made between the plurality of power lines; The control terminal of the switching module is connected to the control module; the control module is used to control the switching module to turn on when no abnormality is detected in the circuit state, and to control the switching module to turn off when an abnormality is detected in the circuit state, based on the operating parameters of the capacitor.

2. The circuit according to claim 1, characterized in that, The electromagnetic interference suppression circuit also includes a first voltage detection device and multiple first current detection devices; The first voltage detection device is connected to the plurality of power lines at both ends, and is used to detect the voltage difference between the plurality of power lines. The plurality of first current detection devices are respectively installed on the plurality of power lines for detecting the current of the power line. The control module is connected to the first voltage detection device and the plurality of first current detection devices. The control module is used to calculate the power parameters of the capacitor based on the detection results of the first voltage detection device and the plurality of first current detection devices, and to control the switching module based on the power parameters.

3. The circuit according to claim 1, characterized in that, The electromagnetic interference suppression circuit further includes: a second current detection device; The second current detection device is connected in series with the capacitor and the switching module, and is used to detect the current flowing through the capacitor; The control module is connected to the second current detection device and is used to control the switching module based on the detection result of the second current detection device.

4. The circuit according to claim 1, characterized in that, The electromagnetic interference suppression circuit also includes: a temperature sensor; The temperature sensor is used to collect the temperature of the capacitor; The temperature sensor is connected to the control module, which controls the switching module based on the temperature of the capacitor.

5. The circuit according to any one of claims 1 to 4, characterized in that, The switching module includes a transistor, and the control terminal of the transistor is connected to the control module.

6. A switching power supply device, characterized in that, An anti-electromagnetic interference circuit as described in any one of claims 1 to 5 is provided between the multiple power lines of the switching power supply device.

7. The switching power supply device according to claim 6, characterized in that, The switching power supply device is a three-phase power supply, and the switching power supply module is connected to the input power supply through a first power line, a second power line, and a third power line.

8. The switching power supply device according to claim 7, characterized in that, An anti-electromagnetic interference circuit is provided between any two of the first, second, and third power lines.

9. The switching power supply device according to claim 7, characterized in that, In the first power line, the second power line, and the third power line, an anti-electromagnetic interference circuit is provided between each power line and the common connection line.

10. The switching power supply device according to claim 9, characterized in that, The switching power supply device further includes: a first resistor, a second resistor, and a third resistor with the same resistance value; The electromagnetic interference suppression circuit between each power line and the common connection line is connected to the first common point. One end of the first resistor, one end of the second resistor, and one end of the third resistor are respectively connected to the first power line, the second power line, and the third power line, and the other ends of the first resistor, the second resistor, and the third resistor are all connected to the second common point. The control module of the electromagnetic interference suppression circuit is used to control the switching module of the electromagnetic interference suppression circuit based on the voltage difference between the first common point and the second common point.

11. The switching power supply device according to claim 10, characterized in that, The switching power supply device also includes a second voltage detection device; The second voltage detection device is connected to the first common point, the second common point, and the control module; the second voltage detection device is used to detect the voltage difference between the first common point and the second common point.

12. The switching power supply device according to claim 11, characterized in that, The second voltage detection device includes: a fourth resistor and a fifth resistor; One end of the fourth resistor is connected to the first common point, the other end of the fourth resistor is connected to one end of the fifth resistor, and the other end of the fifth resistor is connected to the second common point; The control module is connected to both ends of the fifth resistor and is used to control the switching module of the electromagnetic interference suppression circuit according to the voltage difference between the two ends of the fifth resistor.

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