Protection circuit and air conditioner

Abstract

According to the protection circuit, a first electric signal input into a PFC circuit is collected through a sampling module, the change rate of a sampling signal is detected through a differential module, differential voltage is obtained, and if the first electric signal is abnormal, for example, the first electric signal can rapidly rise or fall, the first electric signal is not abnormal. If the differential voltage is larger than the first voltage threshold value, the differential voltage obtained by the differential module is too large or too small, so that the control module can control the PFC circuit to stop working under the condition that the differential voltage is larger than the first voltage threshold value or smaller than the second voltage threshold value; compared with a mode of identifying abnormity only by detecting overlarge voltage input into the PFC circuit or overlarge current input into the PFC circuit in the prior art, the method has the advantages that the response speed can be increased, the phenomenon of damage to the PFC circuit can be reduced, various abnormities occurring in the first electric signal can be detected and responded, the protection comprehensiveness is improved, and the safety of the PFC circuit is improved. And the damage phenomenon of the PFC circuit is further reduced.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuit protection, and in particular to a protection circuit and an air conditioner. Background Art

[0002] A PFC (Power Factor Correction) circuit is a circuit used to improve the power factor of a device, reduce reactive power in the power grid, and lower harmonic interference.

[0003] Air conditioners are often equipped with a PFC circuit to improve their energy efficiency. However, if the power grid is poor while the air conditioner is operating, a large current surge can occur in the PFC circuit, potentially damaging it. Utility Model Content

[0004] The embodiments of the present application disclose a protection circuit and an air conditioner, which can reduce the occurrence of damage to a PFC circuit and improve the stability of the PFC circuit.

[0005] The present application discloses a protection circuit, which includes:

[0006] A power factor correction (PFC) circuit is used to perform power factor correction processing on the input first electrical signal to obtain a second electrical signal;

[0007] a control module connected to the PFC circuit, the control module being used to control the working state of the PFC circuit; a sampling module being used to collect the first electrical signal to obtain a sampling signal;

[0008] a differential module connected to the sampling module, the differential module being configured to detect a rate of change of the sampling signal to obtain a differential voltage, wherein the differential voltage is positively correlated with the rate of change;

[0009] The control module is further configured to control the PFC circuit to stop operating when the differential voltage is greater than a first voltage threshold or when the differential voltage is less than a second voltage threshold.

[0010] In this embodiment, a sampling module collects a first electrical signal input to the PFC circuit, and a differentiating module detects the rate of change of the sampled signal, that is, the rate of change of the first electrical signal, to obtain a differential voltage. If the first electrical signal is abnormal, such as a rapid rise or fall, the differential voltage obtained by the differentiating module may be excessively large or insufficient. Therefore, the control module controls the PFC circuit to stop operating when the differential voltage is greater than a first voltage threshold or less than a second voltage threshold. Compared to related art methods that only detect an abnormality when the input voltage or current to the PFC circuit is excessive, this embodiment improves response speed and reduces the risk of PFC circuit damage. Furthermore, the embodiment can detect and respond to multiple abnormalities in the first electrical signal, thereby enhancing comprehensive protection, further reducing the risk of PFC circuit damage, and improving the stability of the PFC circuit.

[0011] In some embodiments, the circuit further comprises:

[0012] a comparison module connected to the differentiation module, the comparison module being configured to compare the differential voltage with a first reference voltage, and to compare the differential voltage with a second reference voltage, and output a first comparison result when the differential voltage is greater than the first reference voltage, or when the differential voltage is less than the second reference voltage; the first reference voltage corresponds to the first voltage threshold, and the second reference voltage corresponds to the second voltage threshold;

[0013] The control module is connected to the comparison module, and is further configured to control the PFC circuit to stop working when receiving the first comparison result.

[0014] In this embodiment, the comparison module directly compares the differential voltage obtained by the differential module with the first reference voltage, and directly compares the differential voltage obtained by the differential module with the second reference voltage to obtain a comparison result. The comparison result can be obtained in a very short time, thereby improving the response speed of the protection circuit.

[0015] In some embodiments, the comparison module includes:

[0016] a first comparator, wherein a negative input terminal of the first comparator is connected to the differential module, a positive input terminal of the first comparator is used to receive the first reference voltage, the first comparator is used to compare the differential voltage with the first reference voltage, and output the first comparison result when the differential voltage is greater than the first reference voltage;

[0017] a second comparator, wherein a positive input terminal of the second comparator is connected to the differential module, a negative input terminal of the second comparator is used to receive the second reference voltage, the second comparator is used to compare the differential voltage with the second reference voltage, and output the first comparison result when the differential voltage is less than the first reference voltage;

[0018] The control module is connected to the output end of the first comparator and the output end of the second comparator respectively.

[0019] In this embodiment, a first comparator is provided to detect whether the rate of change of the sampling signal is too large, and a second comparator is provided to detect whether the rate of change of the sampling signal is too small. Two comparators are provided to detect whether the first electrical signal has a rapid rise or rapid fall phenomenon. When one of the comparators detects a rapid rise or rapid fall phenomenon, the controller controls the PFC circuit to stop working, thereby improving the response speed of the protection circuit and simplifying the circuit structure. At the same time, the two comparators work independently, which can improve the working reliability of the comparison module.

[0020] In some embodiments, the control module includes a drive circuit and a controller, wherein the drive circuit is connected to the controller and the PFC circuit respectively;

[0021] The driving circuit is further connected to the comparison module, and is configured to send a target level signal to the PFC circuit upon receiving the first comparison result, so as to stop the PFC circuit; and / or

[0022] The controller is further connected to the comparison module. The controller is configured to send a stop signal to the drive circuit upon receiving the first comparison result. The stop signal is configured to trigger the drive circuit to send a target level signal to the PFC circuit to stop the PFC circuit.

[0023] In this embodiment, the control module may include a controller and a driving circuit. By providing a controller and a driving circuit that are independent of each other, the design difficulty of controlling the working state of the PFC circuit can be simplified.

[0024] In some embodiments, the control module includes a drive circuit and a controller, wherein the drive circuit is connected to the controller and the PFC circuit respectively;

[0025] The controller is further connected to the differential module, and is configured to determine whether the differential voltage is greater than the first voltage threshold, and determine whether the differential voltage is less than the second voltage threshold, and output a stop signal to the drive circuit when the differential voltage is greater than the first voltage threshold or the differential voltage is less than the second voltage threshold;

[0026] The driving circuit is configured to send a target level signal to the PFC circuit upon receiving the stop signal, so as to stop the PFC circuit from operating.

[0027] In this embodiment, the controller determines whether the differential voltage is greater than a first voltage threshold and whether the differential voltage is less than a second voltage threshold. When the differential voltage is greater than the first voltage threshold, or when the differential voltage is less than the second voltage threshold, the controller outputs a stop signal to the drive circuit. Upon receiving the stop signal, the drive circuit sends a target level signal to the PFC circuit to stop the PFC circuit. This eliminates the need for additional hardware structure for determining the differential voltage, reduces the manufacturing cost and size of the protection circuit, and also reduces the requirements on the driving capability of the controller, thereby easing the design difficulty of the controller.

[0028] In some embodiments, the control module is further configured to perform analog-to-digital conversion on the differential voltage to obtain a differential voltage value, and to determine whether the differential voltage value is greater than the first voltage threshold, and to determine whether the differential voltage value is less than the second voltage threshold. When the differential voltage value is greater than the first voltage threshold or the differential voltage value is less than the second voltage threshold, the PFC circuit is controlled to stop operating.

[0029] In this embodiment, the control module has an analog-to-digital conversion function, so that the control module can be used to perform analog-to-digital conversion on the differential voltage to obtain a differential voltage value, thereby realizing the judgment of the size relationship between the differential voltage value and the first voltage threshold, as well as the size relationship between the differential voltage value and the second voltage value, thereby reducing the wiring complexity of the protection circuit, reducing the fault points, and improving the stability and reliability of the protection circuit.

[0030] In some embodiments, the differential module includes a capacitor and a resistor, a first end of the capacitor is connected to the sampling module, a second end of the capacitor is connected to a first end of the resistor, and the second end of the resistor serves as an output end of the differential module.

[0031] In this embodiment, in the differential circuit composed of a resistor and capacitor, the capacitor voltage is proportional to the rate of change of the sampled signal, thereby enabling differentiation of the sampled signal. For rapidly changing sampled signals, the differential circuit can amplify the rate of change, allowing the differential voltage to reflect the instantaneous changes in the sampled signal, that is, the instantaneous changes in the first electrical signal, thereby improving the reliability of the protection circuit.

[0032] In some embodiments, the circuit further comprises:

[0033] a filtering module connected to the differential module, and configured to filter out signals in the differential voltage having a frequency higher than a preset frequency;

[0034] The control module is further configured to control the PFC circuit to be in a stopped state when the filtered differential voltage is greater than a first voltage threshold or when the filtered differential voltage is less than a second voltage threshold.

[0035] In this embodiment, considering that the differential module is very sensitive to the high-frequency components of the sampling signal, by setting a filtering module to filter out the signal with a frequency higher than the preset frequency in the differential voltage, the stability of the signal provided to the control module or the comparison module can be guaranteed, and the judgment validity of the control module or the comparison validity of the comparison module can be guaranteed, thereby improving the reliability of the protection circuit.

[0036] In some embodiments, the circuit further comprises:

[0037] A rectifier module is connected to the PFC circuit, and is used to rectify the input AC voltage to obtain the first electrical signal.

[0038] In this embodiment, a rectifier module is provided so that the PFC circuit can obtain a first electrical signal with high stability.

[0039] The embodiments of the present application disclose an air conditioner, comprising any one of the protection circuits disclosed in the embodiments of the present application.

[0040] In this embodiment, the air conditioner includes a protection circuit comprising a PFC circuit, a control module, a sampling module, and a differential module. The control module is connected to the PFC circuit, and the differential module is connected to the sampling module. The control module controls the operating state of the PFC circuit. The PFC circuit performs power factor correction processing on a first input electrical signal to generate a second electrical signal. The sampling module collects the first electrical signal input to the PFC circuit to generate a sampled signal. The differential module detects the rate of change of the sampled signal to generate a differential voltage. A sampling module collects a first electrical signal input to the PFC circuit, and a differentiating module detects the rate of change of the sampled signal, that is, the rate of change of the first electrical signal, to obtain a differential voltage. If the first electrical signal is abnormal, such as a rapid rise or fall of the first electrical signal, the differential voltage obtained by the differentiating module may be excessively large or insufficient. Therefore, the control module controls the PFC circuit to stop operating when the differential voltage is greater than a first voltage threshold or when the differential voltage is less than a second voltage threshold. Compared to related art methods that only detect an abnormality when the input voltage or current to the PFC circuit is excessive, this system can improve response speed and reduce the occurrence of PFC circuit damage. Furthermore, it can detect and respond to multiple abnormalities in the first electrical signal, thereby improving comprehensive protection, further reducing the occurrence of PFC circuit damage, improving the stability of the PFC circuit, ensuring the operational stability of the air conditioner, and improving the safety of the air conditioner. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 It is a structural diagram of an air conditioner in the related art;

[0043] Figure 2 This is a structural diagram of an overcurrent protection circuit in the related art;

[0044] Figure 3 This is a structural diagram of an overvoltage protection circuit in the related art;

[0045] Figure 4 This is one of the structural diagrams of a protection circuit disclosed in the embodiments of the present application;

[0046] Figure 5 This is the second structural diagram of a protection circuit disclosed in an embodiment of the present application;

[0047] Figure 6This is the third structural diagram of a protection circuit disclosed in an embodiment of the present application;

[0048] Figure 7 is a schematic diagram of the module structure of a comparison module disclosed in an embodiment of the present application;

[0049] Figure 8 This is the fourth structural diagram of a protection circuit disclosed in an embodiment of the present application;

[0050] Figure 9 This is the fifth structural diagram of a protection circuit disclosed in the embodiment of the present application;

[0051] Figure 10 This is a schematic structural diagram of a differential module and a filtering module disclosed in an embodiment of the present application;

[0052] Figure 11 This is the sixth structural diagram of a protection circuit disclosed in an embodiment of the present application;

[0053] Figure 12 It is a flowchart of the processing flow of the controller disclosed in the embodiment of this application. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0055] It should be noted that the terms "including," "having," and any variations thereof in the embodiments and drawings of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to the process, method, product, or apparatus.

[0056] A PFC (Power Factor Correction) circuit is a circuit used to improve the power factor of electronic devices, reduce reactive power in the power grid, and lower harmonic interference. Its main function is to keep the current signal corresponding to the input electrical signal of the electronic device and the voltage signal corresponding to the input electrical signal in phase, thereby improving the power factor and further improving the energy utilization efficiency of the electronic device.

[0057] The PFC circuit may include a passive PFC circuit and an active PFC circuit.

[0058] Among them, the passive PFC circuit is relatively simple. The passive PFC circuit mainly includes passive components (such as inductors, capacitors, filters, etc.), and improves the power factor through these passive components.

[0059] Among them, the active PFC circuit mainly includes power switching devices (such as MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) and IGBT (Insulated Gate Bipolar Transistor). By controlling the switching state of the power switching device, the current waveform is dynamically adjusted to achieve a higher power factor.

[0060] PFC circuits are often installed in various electronic devices to improve their energy efficiency, including but not limited to display devices, air conditioners, audio equipment, and medical equipment. Air conditioners can include variable-frequency air conditioners and fixed-frequency air conditioners.

[0061] Since active PFC circuits are smaller in size and weight than passive PFC circuits, and can control the waveform of the input current corresponding to the input electrical signal, which can significantly reduce harmonic distortion, most electronic devices are equipped with active PFC circuits.

[0062] Please refer to Figure 1 , which shows a structural diagram of an air conditioner in the related art, such as Figure 1 As shown, the air conditioner 100 may include a load 110 , a PFC circuit 120 and a control module 130 . The PFC circuit 120 is connected to the load 110 , and the control module 130 is connected to the PFC circuit 120 .

[0063] The PFC circuit 120 is used to perform power factor correction on the input first electrical signal to obtain a second electrical signal, and the control module 130 is used to control the working state of the PFC circuit 120. The load 110 is used to receive the second electrical signal and operate based on the second electrical signal.

[0064] Exemplarily, the first electrical signal may include a current signal and / or a voltage signal.

[0065] Exemplarily, the control module 130 may be configured to output a PWM (Pulse Width Modulation) signal to the PFC circuit 120 to control the on / off (switching state) of the power switching device of the PFC circuit 120, thereby adjusting the waveform of the input current signal to achieve phase synchronization between the current and voltage of the first electrical signal and minimize harmonic distortion.

[0066] Exemplarily, the operating state may include an operating state and a stopped operating state. The stopped operating state may mean that the power switching device in the PFC circuit 120 stops operating, that is, the PFC circuit 120 does not perform power factor correction processing on the first electrical signal. The operating state may mean that the power switching device in the PFC circuit 120 operates according to a set switching state to implement power factor correction processing on the first electrical signal.

[0067] The switching state may include the switching frequency and duty cycle of the power switch. The switching frequency refers to the number of times the power switch is turned on and / or off within a cycle. The duty cycle refers to the ratio of the on-time of the power switch to the total duration of the cycle.

[0068] Exemplarily, the control module 130 may be configured to generate a target drive signal based on a voltage signal and / or a current signal input to the PFC circuit 120, and send the target drive signal to the PFC circuit 120 to control the operating state of the PFC circuit 120 so that the waveform of the current signal and the waveform of the voltage signal are kept as synchronized as possible.

[0069] For example, the load 110 may include but is not limited to a motor, an electric heater, and the like.

[0070] For example, the motor may include but is not limited to a compressor, an indoor fan, etc.

[0071] Among them, the electric heater is used to heat the air or other media in the heating mode, and the heated air is sent into the indoor environment to achieve temperature increase.

[0072] Among them, the compressor is used to compress the refrigerant and push the refrigerant to circulate in the air-conditioning system to achieve cooling or heating.

[0073] Among them, the indoor fan is used to adjust the wind speed of the air conditioner. The faster the speed of the indoor fan, the faster the air flows and the greater the wind speed; conversely, when the speed of the indoor fan decreases, the wind speed will also decrease.

[0074] For example, Figure 1 As shown, the load 110 may include an inverter 141 and a compressor 142, and the compressor 142 may be connected to the inverter 141. The air conditioner shown in this embodiment is a variable frequency air conditioner.

[0075] The inverter 141 may be used to provide alternating current (AC) with different frequencies to control the rotational speed of the compressor 142 . The higher the frequency of the AC, the faster the rotational speed of the compressor 142 , and the stronger the cooling or heating capacity of the compressor 142 .

[0076] In some embodiments, please refer to Figure 1 The PFC circuit 120 may include an inductor L1 and a power switch device Q1, wherein a first end of the inductor L1 is connected to the rectifier module 140, a second end of the inductor L1 is connected to the positive electrode of the load 110 and the first end of the power switch device Q1 respectively, a second end of the power switch device Q1 is connected to the negative DC bus I1, and a third end of the power switch device Q1 is connected to the control module 130.

[0077] It should be noted that inductor L1 and power switch Q1 operate alternately to store and release electrical energy, thereby achieving voltage boost. It should be noted that when PFC circuit 120 stops operating, power switch Q1 is disconnected, protecting power switch Q1. Simultaneously, power can be supplied to load 110 via positive DC bus I2 and negative DC bus I1, ensuring that load 110 can continue to operate and meet user needs.

[0078] Optionally, the power switch device Q1 may include but is not limited to a MOSFET, an IGBT, etc., and the PFC circuit 120 may include one or more power switch devices Q1.

[0079] Exemplarily, the power switch device Q1 includes an IGBT, a first terminal of the power switch device Q1 is a collector of the IGBT, a second terminal of the power switch device Q1 is an emitter of the IGBT, and a third terminal of the power switch device Q1 is a gate of the IGBT.

[0080] Exemplarily, the PFC circuit 120 may further include a first diode D1, wherein the anode of the first diode D1 is connected to the second end of the inductor L1 and the second end of the power switch device Q1, respectively, and the cathode of the first diode D1 is connected to the positive electrode of the load 110. When the power switch device Q1 is turned off, the inductor L1 transfers energy to the load 110 through the first diode D1.

[0081] Exemplarily, the PFC circuit 120 may further include a first capacitor C1, wherein a first end of the first capacitor C1 is connected to the negative DC bus I1, and a second end of the first capacitor C1 is connected to the positive DC bus I2. The first capacitor C1 is used to smooth the output voltage to ensure that the PFC circuit 120 can provide a highly stable DC voltage.

[0082] Exemplarily, the circuit structure of the PFC circuit 120 is a single-channel BOOST circuit topology structure.

[0083] For example, please refer to Figure 1 The air conditioner 100 may further include a rectifier module 140 .

[0084] The rectifier module 140 is used to rectify the AC voltage to obtain the first electrical signal. For example, the AC voltage is a grid voltage, that is, the rectifier module 140 is used to rectify the grid voltage to obtain the first electrical signal.

[0085] However, it has been found in practice that power grid anomalies (such as overvoltage, undervoltage, surge, and harmonic distortion) may cause voltage and current shocks to the power switch device Q1 in the PFC circuit 120, resulting in damage to the power switch device Q1. Therefore, it is urgent to detect the first electrical signal input to the PFC circuit 120 to reduce the occurrence of damage to the PFC circuit 120.

[0086] Considering that when the power grid is abnormal, there may be excessive current or excessive voltage, therefore, an overcurrent protection circuit and an overvoltage protection circuit are provided in the related art.

[0087] like Figure 2 , which shows a schematic structural diagram of an overcurrent protection circuit in the related art. The overcurrent protection circuit 200 may include a PFC circuit 210 , a third comparator 220 , a sampling module 230 and a control module 240 .

[0088] The sampling module 230 is used to collect the current signal Iac input to the PFC circuit 210 to obtain a first sampling signal.

[0089] The third comparator 220 is configured to output a third comparison result when the first sampling signal is greater than a third reference voltage.

[0090] The control module 240 is connected to the output end of the third comparator 220 . The control module 240 is configured to control the PFC circuit 210 to stop working when receiving the third comparison result.

[0091] An analysis of the overcurrent protection circuit 200 shows that the protection action is triggered only when the first sampling signal is greater than the third reference voltage, that is, when the PFC circuit 210 is actually overloaded. However, when an abnormality such as undercurrent occurs in the power grid, the input current signal is not very large. In other words, the overcurrent protection circuit 200 cannot detect abnormalities such as undercurrent. The overcurrent protection circuit 200 can detect and respond to a limited number of abnormality types, and its reliability is poor.

[0092] Please refer to Figure 3 , which shows a schematic diagram of the structure of an overvoltage protection circuit in the related art. The overvoltage protection circuit 300 may include a PFC circuit 310, a fourth comparator 320, a sampling module 330 and a control module 340.

[0093] The sampling module 330 is used to collect the voltage signal Vin input to the PFC circuit 310 to obtain a second sampling signal.

[0094] The fourth comparator 320 is configured to output a fourth comparison result when the second sampling signal is greater than a fourth reference voltage.

[0095] The control module 340 is connected to the output terminal of the fourth comparator 320 . The control module 340 is configured to control the PFC circuit 310 to stop working when receiving the fourth comparison result.

[0096] An analysis of the above-described overvoltage protection circuit 300 shows that protection is triggered only when the second sampling signal is greater than the fourth reference voltage, that is, when the voltage signal Vin input to the PFC circuit 210 exceeds a normal voltage threshold. However, the overvoltage protection circuit 300 is unable to trigger protection in other non-overvoltage abnormal conditions. The overvoltage protection circuit 300 also has the disadvantage of being able to detect and respond to a limited number of fault types, resulting in poor reliability.

[0097] Researchers of the present application conducted further research on the above-mentioned overcurrent protection circuit 200 and overvoltage protection circuit 300 and found that the above-mentioned protection circuits will only trigger protection when the current signal is greater than the corresponding threshold value, or the voltage signal is greater than the corresponding threshold value. It takes a certain amount of time for the current signal to increase from the normal range to the threshold value corresponding to the current signal, and for the voltage signal to increase from the normal range to the threshold value corresponding to the voltage signal. It can be seen that the above-mentioned overcurrent protection circuit 200 and overvoltage protection circuit 300 still have a response lag phenomenon, which makes it easy for the PFC circuit 210 to be damaged.

[0098] The embodiments of the present application disclose a protection circuit and an air conditioner. The protection circuit can respond to multiple types of abnormalities with a fast response speed, thereby reducing the occurrence of PFC circuit damage and improving the stability of the PFC circuit.

[0099] Please refer to Figure 4 , which shows one of the structural diagrams of a protection circuit provided by an embodiment of the present application. Figure 4 As shown, the protection circuit 400 may include a PFC circuit 410 , a control module 420 , a sampling module 430 and a differential module 440 . The control module 420 is connected to the PFC circuit 410 , and the differential module 440 is connected to the sampling module 430 .

[0100] The PFC circuit 410 is configured to perform power factor correction on an input first electrical signal to generate a second electrical signal. The control module 420 is configured to control the operating state of the PFC circuit 410. The sampling module 430 is configured to collect the first electrical signal to generate a sampled signal. The differential module 440 is configured to detect the rate of change of the sampled signal to generate a differential voltage. The control module 420 is further configured to control the PFC circuit 410 to stop operating if the differential voltage exceeds a first voltage threshold or falls below a second voltage threshold.

[0101] It should be noted that the differential voltage is positively correlated with the sampling signal, and the rate of change of the sampling signal is positively correlated with the rate of change of the first electrical signal. Therefore, the differential module 440 detects the rate of change of the sampling signal, and the obtained differential voltage is also positively correlated with the rate of change of the first electrical signal.

[0102] It should be noted that the first voltage threshold is used to measure whether the rate of change of the sampling signal is too large, that is, whether the rising speed of the sampling signal is too fast. If the differential voltage is greater than the first voltage threshold, it is considered that the rising speed of the sampling signal is too fast, that is, the rising speed of the first electrical signal is too fast.

[0103] Similarly, the second voltage threshold can be used to measure whether the rate of change of the first electrical signal is too small, that is, whether the falling speed of the sampling signal is too small. If the differential voltage is less than the second voltage threshold, it is considered that the falling speed of the sampling signal is too fast, that is, the falling speed of the first electrical signal is too fast.

[0104] It is understandable that the first voltage threshold and the second voltage threshold can be set according to actual needs, which is not limited in this embodiment. For example, the first voltage threshold and the second voltage threshold can be determined according to the signal fluctuation degree that the power switch device can withstand and the structure of the sampling module 430.

[0105] Exemplarily, the control module 420 is further configured to control the PFC circuit 410 to operate when the differential voltage is greater than or equal to the second voltage threshold and less than or equal to the first voltage threshold. It should be noted that when the differential voltage is greater than or equal to the second voltage threshold and less than or equal to the first voltage threshold, it can be assumed that there is no abnormality in the input first electrical signal. In this case, the control module 420 can control the PFC circuit 410 to maintain phase alignment between the current signal and the voltage signal, thereby improving the power factor.

[0106] It should be noted that when the first electrical signal experiences an abnormality such as overvoltage, undervoltage, overcurrent, undercurrent, surge, or harmonic distortion, the first electrical signal may experience an excessively large or insufficient rate of change. Since the control module 420 controls the PFC circuit 410 to stop operating when the differential voltage is greater than the first voltage threshold or less than the second voltage threshold, the PFC circuit 410 can be controlled to stop operating when the first electrical signal rises or falls rapidly, thereby preventing damage to the PFC circuit 410. The protection circuit 400 provided in this embodiment of the present application can detect and respond to a wide range of fault types. Upon detecting a rapid rise or fall in the first electrical signal, the PFC circuit 410 is controlled to stop operating without waiting for the current or voltage to reach the corresponding threshold. This improves the response speed of the protection circuit 400 and significantly reduces the risk of damage to the PFC circuit.

[0107] In some embodiments, please refer to Figure 5 The sampling module 510 may include a first resistor R1 and a second resistor R2 connected in series, and a midpoint between the first resistor R1 and the second resistor R2 is connected to the differential module 440 .

[0108] It should be noted that the first resistor R1 and the second resistor R2 realize voltage division of the voltage signal, so the output signal of the connection midpoint between the first resistor R1 and the second resistor R2 is positively correlated with the first electrical signal, that is, the output signal of the connection midpoint is positively correlated with the change rate of the first electrical signal.

[0109] Exemplarily, v1=v2*R2 / (R1+R2), where v1 is the voltage corresponding to the sampling signal, v2 is the voltage corresponding to the first electrical signal, r1 is the resistance of the first resistor R1, and r21 is the resistance of the second resistor R2.

[0110] For example, please refer to Figure 5 The sampling module may further include a second capacitor C2 connected to a midpoint between the first resistor R1 and the second resistor R2.

[0111] It is understandable that the resistance values ​​of the first resistor R1 and the second resistor R2 can be set as needed, and this embodiment does not limit this.

[0112] Exemplarily, the PFC circuit 410 may be connected to a DC power module to receive a first electrical signal provided by the DC power module. The first electrical signal may include a current signal and a voltage signal.

[0113] In some embodiments, please refer to Figure 5The protection circuit may further include a rectifier module 520 , the sampling module 430 is connected to the negative terminal of the rectifier module 520 , and the sampling module 430 is used to collect current signals.

[0114] It should be noted that the rectifier module 520 is used to rectify the AC voltage to generate a first electrical signal. A current signal corresponding to this first electrical signal flows from the positive terminal of the rectifier module 520 to the load and back to the negative terminal of the rectifier module 520, thus forming a closed current loop. Because the current remains consistent within a closed loop, the sampling module 430 is connected to the negative terminal of the rectifier module 520 to sample the current signal input to the PFC circuit 410. Furthermore, because the negative terminal of the rectifier module 520 is close to ground potential, circuit safety is improved.

[0115] In some other embodiments, the protection circuit may further include a rectifier module. The sampling module 430 is connected to the positive terminal of the rectifier module and is used to collect the voltage signal input to the PFC circuit 410 .

[0116] In this embodiment, since the voltage signal changes before the current signal, the sampling module 430 collects the voltage signal input to the PFC circuit 410, thereby further improving the response speed of the protection circuit, thereby further reducing the possibility of damage to the PFC circuit 410 and improving the reliability of the protection circuit.

[0117] In an embodiment of the present application, a sampling module collects a first electrical signal input to the PFC circuit, and a differentiating module detects the rate of change of the sampled signal, that is, the rate of change of the first electrical signal, to obtain a differential voltage. If the first electrical signal is abnormal, such as a rapid rise or fall of the first electrical signal, the differential voltage obtained by the differentiating module may be excessively large or insufficient. Therefore, the control module controls the PFC circuit to stop operating when the differential voltage is greater than a first voltage threshold or when the differential voltage is less than a second voltage threshold. Compared to related art methods that only detect an abnormality when the input voltage or current to the PFC circuit is excessive, this method can improve response speed and reduce the occurrence of PFC circuit damage. Furthermore, it can detect and respond to multiple abnormalities in the first electrical signal, thereby improving comprehensive protection, further reducing the occurrence of PFC circuit damage, and improving the stability of the PFC circuit.

[0118] Please refer to Figure 6 , which shows the third structural diagram of a protection circuit provided by an embodiment of the present application, such as Figure 6As shown, the protection circuit 600 may include a PFC circuit 610 , a control module 620 , a sampling module 630 , a differential module 640 , and a comparison module 650 . The comparison module 650 is connected to the differential module 640 and the control module 620 , respectively.

[0119] The comparison module 650 is configured to compare the differential voltage with a first reference voltage and a second reference voltage, and output a first comparison result when the differential voltage is greater than the first reference voltage or less than the second reference voltage. The control module 620 is further configured to control the PFC circuit 610 to stop operating upon receiving the first comparison result.

[0120] The first reference voltage corresponds to the first voltage threshold, and the second reference voltage corresponds to the second voltage threshold. It should be noted that the first reference voltage, the second reference voltage, and the differential are all analog voltages, and the comparison of the analog voltages is achieved through the comparison module 650.

[0121] Exemplarily, the comparison module 650 is configured to compare the differential voltage with a first reference voltage and a second reference voltage, and output a second comparison result when the differential voltage is less than or equal to the first reference voltage and greater than or equal to the second reference voltage.

[0122] Exemplarily, upon receiving the second comparison result, the control module 620 controls the PFC circuit 610 to operate.

[0123] Exemplarily, the second comparison result may include a first level signal, and the first comparison result may include a second level signal, wherein the first level signal is greater than the second level signal.

[0124] In another example, the second comparison result may include a second level signal, and the first comparison result may include a third level signal, wherein the first level signal is greater than the second level signal.

[0125] In this embodiment, the comparison module 650 directly compares the differential voltage obtained by the differential module 640 with the first reference voltage, and directly compares the differential voltage obtained by the differential module 640 with the second reference voltage to obtain a comparison result. The comparison result can be obtained in a very short time, thereby improving the response speed of the protection circuit 600.

[0126] Please refer to Figure 7 , which shows a schematic diagram of the module structure of a comparison module provided in an embodiment of the present application. Figure 7As shown, the comparison module 710 may include a first comparator Q2 and a second comparator Q3. The negative input terminal of the first comparator Q2 is connected to the differentiation module 720, and the positive input terminal of the first comparator Q2 is used to receive the first reference voltage. The positive input terminal of the second comparator Q3 is connected to the differentiation module 720, and the negative input terminal of the second comparator Q3 is used to receive the second reference voltage. The control module 730 is connected to the output terminal of the first comparator Q2 and the output terminal of the second comparator Q3, respectively.

[0127] The first comparator Q2 is used to compare the differential voltage with a first reference voltage, and output a first comparison result when the differential voltage is greater than the first reference voltage. The second comparator Q3 is used to compare the differential voltage with a second reference voltage, and output a first comparison result when the differential voltage is less than the first reference voltage. The control module 730 is further used to control the PFC circuit to stop operating upon receiving the first comparison result.

[0128] Exemplarily, when the differential voltage is greater than the first reference voltage, the first comparator Q2 outputs the first comparison result from the output terminal of the first comparator Q2, and when the differential voltage is less than the second reference voltage, the second comparator Q3 outputs the first comparison result from the output terminal of the second comparator Q3.

[0129] It should be noted that, when the first comparator Q2 outputs the first comparison result or the second comparator Q3 outputs the first comparison result, the control module 730 receives the first comparison result.

[0130] Exemplarily, the first comparator Q2 is further configured to output a second comparison result when the differential voltage is less than or equal to the first reference voltage, and the second comparator Q3 is further configured to output a second comparison result when the differential voltage is greater than or equal to the second reference voltage.

[0131] It should be noted that, when the first comparator Q2 outputs the second comparison result and the second comparator Q3 also outputs the second comparison result, the control module 730 receives the second comparison result.

[0132] Exemplarily, the first comparison result is a low-level voltage, and the second comparison result is a high-level voltage, that is, the voltage value corresponding to the first comparison result is smaller than the voltage value corresponding to the second comparison result.

[0133] Exemplarily, the output terminal of the first comparator Q2 may be an open-drain electrode structure or an open-collector structure, and the output terminal of the second comparator Q3 may be an open-drain electrode structure or an open-collector structure.

[0134] It should be noted that in the open-drain electrode structure and the open-collector electrode structure, when the output terminal of the comparator outputs a low-level signal, the transistor inside the comparator is turned on, and the output terminal of the comparator is connected to ground. When the output terminal of the comparator outputs a high-level signal, the transistor inside the comparator is turned off, and the output is left floating. Therefore, in this embodiment, when any comparator outputs the first comparison result, the control module 730 receives the first comparison result.

[0135] For example, please refer to Figure 7 The comparison module 710 may further include a first pull-up resistor R3 and a second pull-up resistor R4. The first end of the first pull-up resistor R3 is connected to the voltage input terminal Vcc, and the second end of the first pull-up resistor R3 is connected to the output terminal of the first comparator Q2 and the control module 730. The first end of the second pull-up resistor R4 is connected to the voltage input terminal Vcc, and the second end of the second pull-up resistor R4 is connected to the output terminal of the second comparator Q3 and the control module 730.

[0136] In this embodiment, by setting the first pull-up resistor R3 and the second pull-up resistor R4, when the first comparator Q2 and the second comparator Q3 both output the second comparison result, the control module 730 can receive the second comparison result instead of being in a suspended state, thereby improving the stability of the circuit.

[0137] For example, please refer to Figure 7 The comparison module 710 further includes a third resistor R5 and a third capacitor C3 connected in series, wherein a first end of the third resistor R5 is respectively connected to the output end of the first comparator Q2 and the second end of the first pull-up resistor R3, and a first end of the third capacitor C3 is grounded.

[0138] In this embodiment, the third resistor R5 and the third capacitor C3 connected in series can ensure the stability of the comparison result output by the first comparator Q2 received by the control module 730 .

[0139] For example, please refer to Figure 7 The comparison module further includes a fourth resistor R6 and a fourth capacitor C4 connected in series, wherein a first end of the fourth resistor R6 is respectively connected to the output end of the second comparator Q3 and the second end of the second pull-up resistor R4, and a first end of the fourth capacitor C4 is grounded.

[0140] In this embodiment, the fourth resistor R6 and the fourth capacitor C4 connected in series can ensure the stability of the comparison result output by the second comparator Q3 received by the control module 730 .

[0141] In some embodiments, please refer to Figure 7The comparison module may further include a first bias module 711, wherein the voltage at the output end of the first bias module 711 is a first reference voltage. The output end of the first bias module 711 is connected to the positive input end of the first comparator Q2.

[0142] Exemplarily, the first bias module 711 includes a fifth resistor R7 and a sixth resistor R8 connected in series, a first end of the fifth resistor R7 is connected to the voltage input terminal Vcc, a first end of the sixth resistor R8 is connected to the ground terminal, and a connection midpoint between the fifth resistor R7 and the sixth resistor R8 is the output terminal of the first bias module 711.

[0143] Exemplarily, the first bias module 711 may further include a fifth capacitor C5, a first end of the fifth capacitor C5 being connected to the first end of the fifth resistor R7, and a second end of the fifth capacitor C5 being connected to the first end of the sixth resistor R8, thereby improving the stability of the first reference voltage provided to the positive input terminal of the first comparator Q2.

[0144] In some embodiments, please refer to Figure 7 The comparison module may further include a second bias module 712, wherein the voltage at the output end of the second bias module 712 is a second reference voltage. The output end of the second bias module 712 is connected to the positive input end of the second comparator Q3.

[0145] Exemplarily, the second bias module 712 may include a seventh resistor R9 and an eighth resistor R10 connected in series, a first end of the seventh resistor R9 is connected to the voltage input terminal Vcc, a first end of the eighth resistor R10 is connected to the ground terminal, and a connection midpoint between the seventh resistor R9 and the eighth resistor R10 serves as the output terminal of the second bias module 712.

[0146] Exemplarily, the second bias module 712 may further include a sixth capacitor C6, a first end of the sixth capacitor C6 connected to the first end of the seventh resistor R9, and a second end of the sixth capacitor C6 connected to the first end of the eighth resistor R10, thereby improving the stability of the second reference voltage.

[0147] In this embodiment, a first comparator Q2 is provided to detect whether the rate of change of the sampling signal is too large, and a second comparator Q3 is provided to detect whether the rate of change of the sampling signal is too small. Two comparators are provided to detect whether the first electrical signal has a rapid rise or rapid fall. When one of the comparators detects a rapid rise or rapid fall, the controller controls the PFC circuit to stop working, thereby improving the response speed of the protection circuit and simplifying the circuit structure. At the same time, the two comparators work independently, which can improve the working reliability of the comparison module.

[0148] Please refer to Figure 8, which shows the fourth structural diagram of a protection circuit provided by an embodiment of the present application. Figure 8 As shown, the protection circuit 800 includes a PFC circuit 810, a control module, a sampling module 820, a differential module 830 and a comparison module 840, wherein the control module includes a drive circuit 851 and a controller 852, wherein the drive circuit 851 is connected to the controller 852 and the PFC circuit 810 respectively.

[0149] The controller 852 is configured to generate a control signal based on the first electrical signal. The drive circuit 851 is configured to amplify the power of the control signal to obtain a target drive signal, and then transmit the target drive signal to the PFC circuit 810 to drive the PFC circuit 810 to operate according to the switching state corresponding to the control signal.

[0150] It should be noted that the controller 852 can determine the switching state of the power switching device of the PFC circuit 810 based on the current signal and / or the voltage signal, and then generate a control signal. The control signal output by the controller 852 has a relatively low power. The control signal is converted into a target drive signal capable of driving the PFC circuit to operate through the drive circuit 851, thereby achieving power factor correction processing on the first electrical signal.

[0151] In some embodiments, the driving circuit 851 is further connected to the comparison module 840 . The driving circuit 851 is configured to send a target level signal to the PFC circuit 810 upon receiving the first comparison result, so as to stop the PFC circuit 810 from operating.

[0152] Exemplarily, the first comparison result may be a low level signal, the target level signal may be a low level signal, and when the driving circuit 851 receives the low level signal, it sends a low level signal to the PFC circuit 810 to stop the PFC circuit 810 from operating.

[0153] Exemplarily, the protection circuit may further include a second diode D2, the anode of the second diode D2 is connected to the drive circuit 851, and the cathode of the second diode D2 is connected to the comparison module 840 to prevent the current of the drive circuit 851 from flowing back to the comparison module 840, that is, to prevent the comparison module 840 from being damaged.

[0154] Exemplarily, the driving circuit 851 may be connected to the output terminal of the first comparator and the output terminal of the second comparator respectively.

[0155] In this embodiment, when the differential voltage is greater than the first reference voltage, or the differential voltage is less than the second reference voltage, the first comparison result output by the comparison module 840 is used to control the drive circuit 851 to send a target drive signal to the PFC circuit 810 to stop the PFC circuit 810. This does not rely on the software response of the controller 852. This can improve the speed at which the drive circuit controls the PFC circuit to stop operating, thereby improving the response speed of the protection circuit.

[0156] In some other embodiments, the controller 852 is further connected to the comparison module 840 , and the controller 852 is configured to send a stop signal to the driving circuit 851 upon receiving the first comparison result.

[0157] The stop signal is used to trigger the driving circuit 851 to send a target level signal to the PFC circuit 810 so as to stop the PFC circuit 810 from operating.

[0158] Exemplarily, the controller 852 is connected to the output terminal of the first comparator and the output terminal of the second comparator respectively.

[0159] In some further embodiments, the driving circuit 851 is further connected to the comparison module 840, and the controller 852 is further connected to the comparison module 840. The driving circuit 851 is configured to, upon receiving the first comparison result, send a target level signal to the PFC circuit 810 to stop the PFC circuit 810. The controller 852 is configured to, upon receiving the first comparison result, send a stop signal to the driving circuit 851.

[0160] In this embodiment, the driver circuit 851 may send a target level signal to the PFC circuit 810 in response to the first comparison result output by the comparison module 840 and the stop signal sent by the controller 852 to stop the PFC circuit 810, thereby implementing software protection and hardware protection, thereby improving the safety and reliability of the protection circuit.

[0161] In this embodiment, the control module may include a controller 852 and a driving circuit 851 . By providing the controller 852 and the driving circuit 851 independently of each other, the design difficulty of controlling the working state of the PFC circuit 810 may be simplified.

[0162] In other embodiments, the comparison module 840 may include a fifth comparator, a sixth comparator, and an OR gate module. The positive input of the fifth comparator is connected to the differentiation module 830, the negative input of the fifth comparator is used to receive the first reference voltage, the negative input of the sixth comparator is connected to the differentiation module 830, and the positive input of the second comparator is used to receive the second reference voltage. The first input of the OR gate module is connected to the output of the fifth comparator, the second input of the OR gate module is connected to the output of the sixth comparator, and the output of the OR gate module is connected to the control module.

[0163] The fifth comparator is configured to compare the differential voltage with the first reference voltage and output a third comparison result when the differential voltage is greater than the first reference voltage. The sixth comparator is configured to compare the differential voltage with the second reference voltage and output a third comparison result when the differential voltage is less than the first reference voltage. The OR gate module is configured to output the third comparison result when either the fifth comparator or the sixth comparator outputs the third comparison result. The control module is further configured to send a stop signal to the drive circuit 851 upon receiving the third comparison result.

[0164] The stop signal is used to trigger the driving circuit 851 to send a target level signal to the PFC circuit 810 so as to stop the PFC circuit 810 from operating.

[0165] Exemplarily, the third comparison result is a high-level signal, and the target-level signal may be a low-level signal.

[0166] The above embodiment provides a technical solution for comparing the differential voltage with the first reference voltage and the second reference voltage through an analog circuit. The following embodiment will provide a technical solution for comparing the differential voltage with the first voltage threshold and the second voltage threshold through a digital circuit.

[0167] Please refer to Figure 9 , which shows a fifth structural diagram of a protection circuit provided by an embodiment of the present application, such as Figure 9 As shown, the protection circuit 900 may include a PFC circuit 910, a control module, a sampling module 920, and a differential module 930, wherein the differential module 930 is connected to the sampling module 920. The control module may include a drive circuit 941 and a controller 942, wherein the drive circuit 941 is connected to the controller 942 and the PFC circuit 910, respectively, and the controller 942 is further connected to the differential module 930.

[0168] The controller 942 is configured to determine whether the differential voltage is greater than a first voltage threshold and whether the differential voltage is less than a second voltage threshold. If the differential voltage is greater than the first voltage threshold or less than the second voltage threshold, the controller 942 outputs a stop signal to the driver circuit 941. Upon receiving the stop signal, the driver circuit 941 sends a target level signal to the PFC circuit 910 to stop the PFC circuit 910.

[0169] Exemplarily, the controller 942 is further configured to generate a target drive signal based on the first electrical signal when the differential voltage is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold, and send the target drive signal to the PFC circuit 910 to control the operating state of the PFC circuit 910 so that the waveform of the current signal input to the PFC circuit 910 is synchronized as much as possible with the waveform of the voltage signal.

[0170] In some embodiments, the protection circuit may further include an analog-to-digital conversion module, connected to the controller 942 and the differentiating module 930, respectively. The analog-to-digital conversion module is configured to perform analog-to-digital conversion on the differential voltage to obtain a differential voltage value. The controller 942 is configured to determine whether the differential voltage value is greater than a first voltage threshold and less than a second voltage threshold. If the differential voltage value is greater than the first voltage threshold or less than the second voltage threshold, the controller 942 outputs a stop signal to the driver circuit 941. Upon receiving the stop signal, the driver circuit 941 sends a target level signal to the PFC circuit 910 to stop the PFC circuit 910.

[0171] It should be noted that the analog-to-digital conversion process refers to converting an analog signal into a digital signal, that is, converting the differential voltage output by the differential module 930 into a differential voltage value that can be recognized and processed by the controller 942 .

[0172] In this embodiment, the controller 942 determines whether the differential voltage is greater than a first voltage threshold and whether the differential voltage is less than a second voltage threshold. When the differential voltage is greater than the first voltage threshold, or when the differential voltage is less than the second voltage threshold, the controller 942 outputs a stop signal to the driver circuit 941. Upon receiving the stop signal, the driver circuit 941 sends a target level signal to the PFC circuit 910 to stop the PFC circuit 910. This eliminates the need for additional hardware to determine the differential voltage, reduces the manufacturing cost and size of the protection circuit, and reduces the driving capability requirements of the controller 942, thereby simplifying the design of the controller 942.

[0173] In some embodiments, the control module is further used to perform analog-to-digital conversion on the differential voltage to obtain a differential voltage value, and to determine whether the differential voltage value is greater than a first voltage threshold, and to determine whether the differential voltage value is less than a second voltage threshold. When the differential voltage value is greater than the first voltage threshold, or the differential voltage value is less than the second voltage threshold, the PFC circuit 910 is controlled to stop working.

[0174] In some embodiments, the control module further includes a controller 942 and a drive circuit 941. The drive circuit 941 is connected to the controller 942 and the PFC circuit 910, respectively. The controller 942 is also connected to the differential module 930. The controller 942 is configured to perform analog-to-digital conversion on the differential voltage to obtain a differential voltage value, and to determine whether the differential voltage value is greater than a first voltage threshold or less than a second voltage threshold. If the differential voltage value is greater than the first voltage threshold or less than the second voltage threshold, the controller 942 sends a stop signal to the drive circuit 941. The stop signal triggers the drive circuit 941 to send a target level signal to the PFC circuit 910, thereby stopping the PFC circuit 910.

[0175] In this embodiment, the control module has an analog-to-digital conversion function, so that the control module can be used to perform analog-to-digital conversion on the differential voltage to obtain a differential voltage value, thereby realizing the judgment of the size relationship between the differential voltage value and the first voltage threshold, as well as the size relationship between the differential voltage value and the second voltage value, thereby reducing the wiring complexity of the protection circuit, reducing the fault points, and improving the stability and reliability of the protection circuit.

[0176] In some embodiments, please refer to Figure 10 The differential module 1010 may include a resistor and a capacitor. For ease of description, the resistor included in the differential module 1010 is referred to as the ninth resistor R11, and the capacitor included in the differential module 930 is referred to as the seventh capacitor C7. A first end of the seventh capacitor C7 is connected to the sampling module 1020, and a second end of the seventh capacitor C7 is connected to a first end of the ninth resistor R11. The second end of the ninth resistor R11 serves as the output end of the differential module 1010, that is, the voltage at the second end of the ninth resistor R11 is the differential voltage.

[0177] The first end of the seventh capacitor C7 is connected to the output end of the sampling module 1020 , ie, the midpoint between the first resistor R1 and the second resistor R2 .

[0178] In this embodiment, in the differential circuit composed of a resistor and capacitor, the capacitor voltage is proportional to the rate of change of the sampled signal, thereby enabling differentiation of the sampled signal. For rapidly changing sampled signals, the differential circuit can amplify the rate of change, allowing the differential voltage to reflect the instantaneous changes in the sampled signal, that is, the instantaneous changes in the first electrical signal, thereby improving the reliability of the protection circuit.

[0179] In some embodiments, please refer to Figure 10 The differential module 1010 may further include an operational amplifier Q4. A negative input terminal of the operational amplifier Q4 is connected to the second terminal of the seventh capacitor C7 and the first terminal of the ninth resistor R11, respectively. A positive input terminal of the operational amplifier Q4 is used to receive a bias voltage. An output terminal of the operational amplifier Q4 is connected to the second terminal of the ninth resistor R11.

[0180] Exemplarily, the protection circuit may further include a third bias module 1030. The third bias module 1030 is connected to the positive input terminal of the operational amplifier Q4, and is configured to provide a bias voltage for the positive input terminal of the operational amplifier Q4.

[0181] For example, please refer to Figure 10 The third bias module may include a tenth resistor R12 and an eleventh resistor R13 connected in series. A first end of the tenth resistor R12 is connected to the voltage input terminal Vcc, a first end of the eleventh resistor R13 is grounded, and a midpoint between the tenth resistor R12 and the eleventh resistor R13 is connected to the positive input terminal of the operational amplifier Q4.

[0182] For example, the bias voltage can be expressed as V_bias=V3*r13 / (r12+r13), where V_bias is the bias voltage, V3 is the voltage value of the voltage input terminal Vcc, r12 is the resistance value of the tenth resistor R12, and r13 is the resistance value of the eleventh resistor R13.

[0183] For example, the differential voltage can be expressed as V_D=-r11*c7*dv1 / dt+V_bias, where V_D is the differential voltage, r11 is the resistance of the ninth resistor, c7 is the capacitance of the seventh capacitor, and v1 is the voltage corresponding to the sampling signal.

[0184] In this embodiment, by providing an operational amplifier Q4 within differential module 1010, the differential voltage can be increased, facilitating comparison and judgment by the comparison module or control module. Furthermore, due to the high input impedance and low output impedance of the operational amplifier, differential module 1010 can more accurately process changes in the sampled signal, avoiding non-ideal effects caused by passive components and ensuring effective protection.

[0185] Please continue to refer to Figure 10The protection circuit may further include a filtering module 1040, which is connected to the differential module 1010 and the control module respectively. The filtering module 1040 is used to filter out signals with a frequency higher than a preset frequency in the differential voltage output by the differential module 1010.

[0186] It should be noted that the differential module 1010 is used to detect the rate of change of the sampled voltage, that is, the differential module 1010 is very sensitive to rapid changes in the input signal. If the sampled voltage is mixed with high-frequency noise, it may cause the differential voltage to have spikes. The differential voltage output by the differential module 1010 is low-pass filtered by the filtering module 1040, that is, the signal with a frequency higher than the preset frequency in the differential voltage is filtered out, which can effectively reduce or suppress the influence of high-frequency noise, thereby improving the comparison result of the comparison module, or the effectiveness of the judgment result of the control module 1050, and improving the reliability of the protection circuit.

[0187] In some embodiments, the control module is further configured to control the PFC circuit to stop operating when the filtered differential voltage is greater than a first voltage threshold, or when the filtered differential voltage is less than a second voltage threshold.

[0188] In some embodiments, the protection circuit also includes a comparison module, the filtering module 1040 is connected to the comparison module, and the comparison module is used to compare the filtered differential voltage with the first reference voltage, and to compare the filtered differential voltage with the second reference voltage. When the filtered differential voltage is greater than the first reference voltage, or the filtered differential voltage is less than the second reference voltage, the first comparison result is output.

[0189] In some embodiments, the filtering module 1040 is connected to the control module, and the control module is used to perform analog-to-digital conversion on the filtered differential voltage to obtain a differential voltage value.

[0190] Exemplarily, the filtering module 1040 may also include a filter resistor R14 and a filter capacitor C8 connected in series, the first end of the filter resistor R14 is connected to the differential module 1010, the first end of the filter capacitor C8 is connected to the ground end, and the connection midpoint between the filter resistor R14 and the filter capacitor C8 serves as the output end of the filtering module 1040, that is, the voltage at the connection midpoint between the filter resistor R14 and the filter capacitor C8 is the filtered differential voltage.

[0191] In this embodiment, considering that the differential module is very sensitive to the high-frequency components of the sampling signal, by setting a filtering module to filter out the signal with a frequency higher than the preset frequency in the differential voltage, the stability of the signal provided to the control module or the comparison module can be guaranteed, and the judgment validity of the control module or the comparison validity of the comparison module can be guaranteed, thereby improving the reliability of the protection circuit.

[0192] Please refer to Figure 11 , which shows the sixth structural diagram of a protection circuit provided by an embodiment of the present application. Figure 11 As shown, the protection circuit includes a rectifier module 1110, a PFC circuit 1120, a drive circuit 1130, a controller 1140, a sampling module 1150, a third bias module 1160, a differential module 1170, and a filter module 1180. The PFC circuit 1120 is configured to connect to a load 1190 to provide the load 1190 with a second electrical signal.

[0193] It should be noted that the voltage signal Vin output by the rectifier module 1110 is sampled by the sampling module 1150, which outputs a sampled signal V_SAMP. The output of the sampling module 1150 is connected to the seventh capacitor C7 of the differentiating module 1170. The seventh capacitor C7, the ninth resistor R11, and the operational amplifier Q4 constitute the differentiating module 1170. The differentiating module 1170 outputs a differential voltage V_D. The third bias module 1160 provides a bias voltage V_bias to the operational amplifier Q4. The output of the operational amplifier Q4 is connected to the filtering module 1180. The differential voltage, after being filtered by the filter resistor R14 and the filter capacitor C8, is output to the controller 1140 for analog-to-digital conversion and related protection logic processing.

[0194] Please refer to Figure 12 , which shows a flow chart of the controller's processing flow. Figure 12 As shown, the controller performs analog-to-digital conversion on the differential voltage to obtain a differential voltage value V_DIFF, and determines whether the differential voltage value V_DIFF is greater than a first voltage threshold VP1. When the differential voltage value V_DIFF is greater than the first voltage threshold VP1, the first fault flag ERR_FLAG1 is set, that is, updated to 1. When the differential voltage value is less than or equal to the first voltage threshold VP1, the first fault flag ERR_FLAG1 remains at 0, and the controller determines whether the differential voltage value V_DIFF is less than a second voltage threshold VP2. When V_DIFF is less than the second voltage threshold VP2, the second fault flag ERR_FLAG2 is set, that is, updated from 0 to 1. If V_DIFF is greater than or equal to the second voltage threshold VP2, the second fault flag ERR_FLAG2 remains at 0. When any fault flag is set, the controller is triggered to shut down the PWM output, causing the PFC circuit to stop operating and provide protection.

[0195] An embodiment of the present application further provides an air conditioner, which may include any one of the protection circuits provided in the above embodiments.

[0196] In an embodiment of the present application, an air conditioner includes a protection circuit comprising a PFC circuit, a control module, a sampling module, and a differential module. The control module is connected to the PFC circuit, and the differential module is connected to the sampling module. The control module controls the operating state of the PFC circuit. The PFC circuit performs power factor correction processing on a first input electrical signal to generate a second electrical signal. The sampling module collects the first electrical signal input to the PFC circuit to generate a sampled signal. The differential module detects the rate of change of the sampled signal to generate a differential voltage. A sampling module collects a first electrical signal input to the PFC circuit, and a differentiating module detects the rate of change of the sampled signal, that is, the rate of change of the first electrical signal, to obtain a differential voltage. If the first electrical signal is abnormal, such as a rapid rise or fall of the first electrical signal, the differential voltage obtained by the differentiating module may be excessively large or insufficient. Therefore, the control module controls the PFC circuit to stop operating when the differential voltage is greater than a first voltage threshold or when the differential voltage is less than a second voltage threshold. Compared to related art methods that only detect an abnormality when the input voltage or current to the PFC circuit is excessive, this system can improve response speed and reduce the occurrence of PFC circuit damage. Furthermore, it can detect and respond to multiple abnormalities in the first electrical signal, thereby improving comprehensive protection, further reducing the occurrence of PFC circuit damage, improving the stability of the PFC circuit, ensuring the operational stability of the air conditioner, and improving the safety of the air conditioner.

[0197] It should be understood that references to "one embodiment" or "an embodiment" throughout this specification mean that a particular feature, structure, or characteristic associated with the embodiment is included in at least one embodiment of the present application. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment. Furthermore, these particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Those skilled in the art should also be aware that the embodiments described in this specification are all optional embodiments, and the actions and modules involved are not necessarily required for this application.

[0198] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple network units. Some or all of these units may be selected based on actual needs to achieve the objectives of this embodiment.

[0199] In addition, the functional units in the embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0200] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-accessible memory. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a memory and includes several requests for a computer device (which can be a personal computer, server or network device, etc., specifically a processor in a computer device) to execute some or all of the steps of the above-mentioned methods of various embodiments of the present application.

[0201] The above describes in detail a protection circuit and air conditioner disclosed in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is intended only to help understand the method and core concept of the present application. At the same time, those skilled in the art will appreciate that variations in the specific implementation methods and scope of application may occur based on the concepts of the present application. In summary, the contents of this specification should not be construed as limiting the present application.

Claims

1. A protection circuit, characterized in that: The circuit comprises: A power factor correction (PFC) circuit is used to perform power factor correction processing on the input first electrical signal to obtain a second electrical signal; a control module connected to the PFC circuit, the control module being used to control the working state of the PFC circuit; a sampling module, configured to collect the first electrical signal to obtain a sampling signal; a differential module connected to the sampling module, the differential module being configured to detect a rate of change of the sampling signal to obtain a differential voltage, wherein the differential voltage is positively correlated with the rate of change; The control module is further configured to control the PFC circuit to stop operating when the differential voltage is greater than a first voltage threshold or when the differential voltage is less than a second voltage threshold.

2. The circuit according to claim 1, wherein: The circuit further comprises: a comparison module connected to the differentiation module, the comparison module being configured to compare the differential voltage with a first reference voltage, and to compare the differential voltage with a second reference voltage, and output a first comparison result when the differential voltage is greater than the first reference voltage, or when the differential voltage is less than the second reference voltage; the first reference voltage corresponds to the first voltage threshold, and the second reference voltage corresponds to the second voltage threshold; The control module is connected to the comparison module, and is further configured to control the PFC circuit to stop working when receiving the first comparison result.

3. The circuit according to claim 2, characterized in that The comparison module includes: a first comparator, wherein a negative input terminal of the first comparator is connected to the differential module, a positive input terminal of the first comparator is used to receive the first reference voltage, the first comparator is used to compare the differential voltage with the first reference voltage, and output the first comparison result when the differential voltage is greater than the first reference voltage; a second comparator, wherein a positive input terminal of the second comparator is connected to the differential module, a negative input terminal of the second comparator is used to receive the second reference voltage, the second comparator is used to compare the differential voltage with the second reference voltage, and output the first comparison result when the differential voltage is less than the first reference voltage; The control module is connected to the output end of the first comparator and the output end of the second comparator respectively.

4. The circuit according to claim 2, characterized in that The control module includes a drive circuit and a controller, wherein the drive circuit is connected to the controller and the PFC circuit respectively; The driving circuit is further connected to the comparison module, and is configured to send a target level signal to the PFC circuit upon receiving the first comparison result, so as to stop the PFC circuit; and / or The controller is further connected to the comparison module. The controller is configured to send a stop signal to the drive circuit upon receiving the first comparison result. The stop signal is configured to trigger the drive circuit to send a target level signal to the PFC circuit to stop the PFC circuit.

5. The circuit according to claim 1, wherein: The control module includes a drive circuit and a controller, wherein the drive circuit is connected to the controller and the PFC circuit respectively; The controller is further connected to the differential module, and is configured to determine whether the differential voltage is greater than the first voltage threshold, and determine whether the differential voltage is less than the second voltage threshold, and output a stop signal to the drive circuit when the differential voltage is greater than the first voltage threshold or the differential voltage is less than the second voltage threshold; The driving circuit is configured to send a target level signal to the PFC circuit upon receiving the stop signal, so as to stop the PFC circuit from operating.

6. The circuit according to claim 1, wherein: The control module is further configured to perform analog-to-digital conversion on the differential voltage to obtain a differential voltage value, determine whether the differential voltage value is greater than the first voltage threshold, and determine whether the differential voltage value is less than the second voltage threshold; and control the PFC circuit to stop operating when the differential voltage value is greater than the first voltage threshold or when the differential voltage value is less than the second voltage threshold.

7. The circuit according to claim 1, wherein: The differential module includes a capacitor and a resistor. The first end of the capacitor is connected to the sampling module, the second end of the capacitor is connected to the first end of the resistor, and the second end of the resistor serves as the output end of the differential module.

8. The circuit according to claim 1, wherein: The circuit further comprises: a filtering module connected to the differential module, and configured to filter out signals in the differential voltage having a frequency higher than a preset frequency; The control module is further configured to control the PFC circuit to be in a stopped state when the filtered differential voltage is greater than a first voltage threshold or when the filtered differential voltage is less than a second voltage threshold.

9. The circuit according to claim 1, wherein: The circuit further comprises: A rectifier module is connected to the PFC circuit, and is used to rectify the input AC voltage to obtain the first electrical signal.

10. An air conditioner, characterized in that: The invention comprises a protection circuit as claimed in any one of claims 1 to 9.

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