Protection structure, air conditioner and control method

Abstract

The invention provides a protection structure, an air conditioner and a control method, and the protection structure comprises a voltage detection module which is used for detecting a first voltage value of a to-be-protected circuit at a first moment, and a time delay module which is used for obtaining a second voltage value of the to-be-protected circuit at a second moment; the subtraction module is used for calculating a difference value between the first voltage value and the second voltage value; the division module is used for dividing the difference value calculated by the subtraction module by the time difference between the second moment and the first moment so as to output a change rate value; the control module controls the to-be-protected circuit according to the change rate value, and the protection structure solves the technical problem that the service life of the protection structure for the circuit is short.

Description

Technical Field

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

[0002] In areas with poor voltage, when the grid voltage fluctuates, the voltage amplitude changes suddenly, which can cause device damage, and protective measures need to be taken for the grid.

[0003] However, the prior art generally uses varistors as protection devices to protect against sudden changes in AC input, but varistors generally have a limited number of uses, and the circuit will fail after multiple discharges, and can only protect against overvoltage but not undervoltage. In addition, the prior art does not protect the subsequent circuit devices. This proposal proposes an AC input sudden change protection circuit and method for a bridgeless PFC circuit.

[0004] Therefore, the prior art needs to be further developed. Summary of the invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies and provide a protection structure, an air conditioner and a control method to solve the technical problem of the short life of the circuit protection structure in the related art.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: a protection structure is provided, including: a first voltage value for detecting when the circuit to be protected is at a first moment; a delay module for obtaining a second voltage value when the circuit to be protected is at a second moment; a subtraction module, the subtraction module is used to calculate the difference between the first voltage value and the second voltage value; a division module, the division module is used to divide the difference calculated by the subtraction module by the time difference between the second moment and the first moment to output a rate of change value; a control module, the control module controls the circuit to be protected according to the rate of change value.

[0007] Furthermore, the protection structure includes a protection module; the protection module includes a switch K and a varistor RV1 connected to the circuit to be protected.

[0008] Furthermore, the voltage detection module includes: a first resistor and a second resistor, the first resistor and the second resistor are both connected to the circuit to be protected, and the subtraction module is connected to the circuit between the first resistor and the second resistor.

[0009] Furthermore, the subtraction module includes: an operational amplifier U1, the positive input terminal of the operational amplifier U1 is connected to the circuit between the first resistor and the second resistor, and the reverse input terminal of the operational amplifier U1 is connected to the delay module to receive the first voltage value and the second voltage value respectively; the output terminal of the operational amplifier U1 is connected to the division module.

[0010] Furthermore, the subtraction module includes: a first circuit connected to the positive input terminal of the operational amplifier U1; the first circuit is connected to the circuit between the first resistor and the second resistor; and a second circuit connected to the reverse input terminal of the operational amplifier U1; wherein the protection structure also includes a delay module, and the delay module is arranged on the second circuit to delay the connection between the reverse input terminal of the operational amplifier U1 and the voltage detection module.

[0011] Furthermore, the division module includes: an analog multiplier U2; an operational amplifier U3, the output end of the analog multiplier U2 is connected to the inverting input end of the operational amplifier U3, the output end of the subtraction module is connected to one input end of the analog multiplier U2, and the other input end of the analog multiplier U2 is connected to the output end of the operational amplifier U3.

[0012] Furthermore, the protection structure also includes an amplification module, which includes an operational amplifier U4; the positive input terminal of the operational amplifier U4 is connected to the output terminal of the operational amplifier U3, and the output terminal of the operational amplifier U4 is connected to the control module.

[0013] Furthermore, the control module is connected to the voltage detection module.

[0014] An air conditioner comprises a protective structure, wherein the protective structure is the above-mentioned protective structure.

[0015] A control method is applicable to the above-mentioned protection structure, and the control method includes: a voltage detection module detects the voltage value of the circuit to be protected; a subtraction module collects the first voltage value and the second voltage value detected by the voltage detection module; wherein the first voltage value is the voltage value collected at the first moment, and the second voltage value is the voltage value collected at the second moment; the second moment is the moment after a delay of a period of time from the first moment; the subtraction module calculates the difference between the first voltage value and the second voltage value; the division module divides the difference calculated by the subtraction module by the time difference between the second moment and the first moment to output a change rate value; and the control module controls the circuit to be protected according to the change rate value.

[0016] Furthermore, the method for controlling the circuit to be protected includes: setting a first overvoltage protection value and a second overvoltage protection value; wherein the first overvoltage protection value is less than the second overvoltage protection value; when the voltage value detected by the voltage detection module is greater than or equal to the second overvoltage protection value, shutting down the circuit to be protected; when the voltage value detected by the voltage detection module is greater than or equal to the first overvoltage protection value, and the voltage value detected by the voltage detection module is less than the second overvoltage protection value, controlling the circuit to be protected according to the rate of change value.

[0017] Furthermore, the method of controlling the circuit to be protected according to the change rate value includes: when the change rate value is greater than or equal to a preset value, controlling the circuit to be protected to only perform rectification without storing energy; and continuing to detect the voltage value; when the change rate value is less than the preset value, the circuit to be protected operates normally.

[0018] Furthermore, the method for controlling the circuit to be protected includes: setting a first under-voltage protection value; when the voltage value detected by the voltage detection module is greater than the first under-voltage protection value, the circuit to be protected works normally; when the voltage value is less than or equal to the first under-voltage protection value, controlling the opening rate and opening time of the switch tube of the circuit to be protected to increase rectification and energy storage.

[0019] Furthermore, the method for controlling the circuit to be protected includes: setting a second undervoltage protection value; when the voltage value detected by the voltage detection module is greater than the second undervoltage protection value, the circuit to be protected works normally; when the voltage value is less than or equal to the second undervoltage protection value, controlling the circuit to be protected to perform undervoltage protection.

[0020] Beneficial effects:

[0021] The protection structure of the present invention includes: a voltage detection module, which is used to detect the first voltage value of the circuit to be protected when it is at the first moment and the second voltage value when it is at the second moment; a subtraction module, which is used to calculate the difference between the first voltage value and the second voltage value; a division module, which is used to divide the difference calculated by the subtraction module with the time difference between the second moment and the first moment to output a change rate value; and a control module, which controls the circuit to be protected according to the change rate value. With the above arrangement, an AC input mutation protection structure of the circuit to be protected is set, by detecting the bus voltage, inputting the instantaneous voltage into the subtraction module to obtain the voltage difference, and then inputting the output signal of the subtraction module into the division module to calculate the voltage change rate. The control module protects the circuit to be protected through the voltage detection module and the voltage change rate control driving circuit. In this way, the protection structure controls the circuit to be protected by collecting the voltage signal, and can be reused for a long time, solving the technical problem of the short life of the protection structure of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the structure of the protection structure used in the embodiment of the present invention;

[0023] Figure 2 is a structural diagram of a voltage detection module of a protection structure adopted in an embodiment of the present invention;

[0024] Figure 3 is a structural diagram of a subtraction module of a protection structure adopted in an embodiment of the present invention;

[0025] Figure 4It is a flow chart of the control method adopted in the embodiment of the present invention.

[0026] The above drawings include the following reference numerals:

[0027] 10. Circuit to be protected;

[0028] 1. Voltage detection module; 11. First resistor; 12. Second resistor; 2. Subtraction module; 21. First circuit; 22. Second circuit; 3. Division module; 4. Control module; 5. Protection module; 6. Amplification module; 7. Delay module. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0030] See also Figures 1 to 4 According to an embodiment of the present invention, a protection structure is provided, comprising: a first voltage value for detecting a circuit to be protected when the circuit is at a first moment; a delay module 7 for deriving a second voltage value for the circuit to be protected when the circuit is at a second moment ； Subtraction module 2, subtraction module 2 is used to calculate the difference between the first voltage value and the second voltage value; division module 3, division module 3 is used to divide the difference calculated by subtraction module 2 with the time difference between the second moment and the first moment to output the change rate value; control module 4, control module 4 controls the circuit to be protected 10 according to the change rate value. With the above settings, an AC input mutation protection structure of the circuit to be protected 10 is set, by detecting the bus voltage, inputting the instantaneous voltage into the subtraction module 2 to obtain the voltage difference, and then inputting the output signal of the subtraction module 2 into the division module 3, so as to calculate the voltage change rate. The control module 4 protects the circuit to be protected 10 through the voltage detection module and the voltage change rate control driving circuit. In this way, the protection structure controls the circuit to be protected 10 by collecting the voltage signal, and can be reused for a long time, solving the technical problem of the short life of the circuit protection structure.

[0031] In the protection structure of this embodiment, see Figure 1 The protection structure includes a protection module 5; the protection module 5 includes a switch K and a varistor RV1 connected to the circuit to be protected 10. In this way, the circuit to be protected 10 can be turned off in time through the switch K and the varistor RV1.

[0032] See also Figure 1 , Figure 2 In the protection structure of this embodiment, the voltage detection module 1 includes: a first resistor 11 and a second resistor 12, both of which are connected to the circuit to be protected 10, and the subtraction module 2 is connected to the circuit between the first resistor 11 and the second resistor 12. In this way, the voltage of the circuit to be protected 10 is collected through the voltage division of the first resistor 11 and the second resistor 12, and the structure is simple.

[0033] Specifically, the voltage detection module includes Figure 1 In the example, R41, R42, R43, and R44, the series connection of R41, R42, and R43 can be regarded as the first resistor 11. The number of resistors is not mandatory, and a suitable resistor and number of resistors can be selected according to the power.

[0034] In the protection structure of this embodiment, see Figure 1 , Figure 3 The subtraction module 2 includes an operational amplifier U1, a positive input terminal of the operational amplifier U1 is connected to the circuit between the first resistor 11 and the second resistor 12, and a negative input terminal of the operational amplifier U1 is connected to the delay module 7. In this way, the calculation of the difference between the first voltage value and the second voltage value is realized, and the structure is simple.

[0035] Specifically, see Figure 1 The subtraction module 2 obtains the voltage difference Ubus between the current voltage and the voltage UB after UA delay and directly outputs it as UA, that is, Ubus=UA. At the same time, Ubus is output as UB through the delay module, and the output of the subtraction module is Uout1=UA-UB.

[0036] See also Figure 1 , Figure 3 In the protection structure of this embodiment, the subtraction module 2 includes: a first circuit 21 connected to the positive input terminal of the operational amplifier U1; a circuit connection between the first circuit 21 and the first resistor 11 and the second resistor 12; a second circuit 22 connected to the reverse input terminal of the operational amplifier U1; wherein the protection structure also includes a delay module 7, which is arranged on the second circuit to delay the connection between the reverse input terminal of the operational amplifier U1 and the voltage detection module. In this way, the first voltage value and the second voltage value can be collected respectively through the delay module 7, so that the voltage values ​​of the circuit to be protected 10 at different times can be obtained without affecting the normal operation of the circuit, thereby improving the working efficiency of the circuit.

[0037] In the protection structure of this embodiment, see Figure 1The division module 3 includes: an analog multiplier U2; an operational amplifier U3, the output end of the analog multiplier U2 is connected to the inverting input end of the operational amplifier U3, the output end of the subtraction module 2 is connected to one input end of the analog multiplier U2, and the other input end of the analog multiplier U2 is connected to the output end of the operational amplifier U3. In this way, the change value of the voltage value is divided by the time difference value to obtain the change rate of the voltage value, so as to control the circuit 10 to be protected according to the change rate, thereby accurately controlling the circuit 10 to be protected.

[0038] See also Figure 1 In the protection structure of this embodiment, the protection structure further includes an amplification module 6, which includes an operational amplifier U4; the positive input terminal of the operational amplifier U4 is connected to the output terminal of the operational amplifier U3, and the output terminal of the operational amplifier U4 is connected to the control module 4. In this way, the signal is amplified and then transmitted to the control module 4, ensuring that the control of the control module 4 is accurate.

[0039] In the protection structure of this embodiment, see Figure 1 , the control module 4 is connected to the voltage detection module 1. In this way, the control module 4 can directly control the voltage detection module 1 through the voltage value of the circuit to be protected 10 detected by the voltage detection module 1, thereby controlling the circuit to be protected 10 more intuitively.

[0040] The air conditioner of this embodiment includes a protection structure, and the protection structure is the above-mentioned protection structure. The AC input mutation protection circuit of the bridgeless PFC circuit of the air conditioner of this embodiment detects the bus voltage, inputs the instantaneous voltage and the delayed voltage into the subtraction module 2 to obtain the voltage difference, and then inputs the output signal of the subtraction module 2 into the division module 3 to calculate the voltage change rate, and inputs it into the amplification module 6 to amplify it. The DSP circuit protects the bridgeless PFC circuit through the voltage detection module 1 and the voltage change rate control driving circuit.

[0041] The control method of this embodiment is applicable to the above protection structure, and the control method includes: the voltage detection module 1 detects the voltage value of the circuit to be protected 10; the subtraction module 2 collects the first voltage value and the second voltage value detected by the voltage detection module 1; wherein the first voltage value is the voltage value collected at the first moment, and the second voltage value is the voltage value collected at the second moment; the second moment is the moment after a delay of a period of time from the first moment; the subtraction module 2 calculates the difference between the first voltage value and the second voltage value; the division module 3 divides the difference calculated by the subtraction module 2 by the time difference between the second moment and the first moment to output the change rate value; the control module 4 controls the circuit to be protected 10 according to the change rate value. Using the above method, by detecting the bus voltage, the instantaneous voltage and the delayed voltage are input into the subtraction module 2 to obtain the voltage difference, and then the output signal of the subtraction module 2 is input into the division module 3, so as to calculate the voltage change rate, and input it into the amplification module 6 to amplify it. The DSP circuit protects the bridgeless PFC circuit through the voltage detection module 1 and the voltage change rate control driving circuit.

[0042] Specifically, by detecting the bus voltage, the instantaneous voltage and the delayed voltage are input into the subtraction module to obtain the voltage difference, and then the output signal of the subtraction module is input into the division module to calculate the voltage change rate, and then input into the amplification module to amplify it. The protection structure protects the bridgeless PFC circuit through the voltage detection module and the voltage change rate control drive circuit. It has the following functions:

[0043] Real-time sampling of bus voltage value;

[0044] Voltage signal delay effect;

[0045] Subtraction operation gives the voltage difference;

[0046] The division operation gives the rate of change of voltage;

[0047] Magnification calculation.

[0048] In the control method of this embodiment, see Figure 4 The method for controlling the circuit to be protected 10 includes: setting a first overvoltage protection value and a second overvoltage protection value; wherein the first overvoltage protection value is less than the second overvoltage protection value; when the voltage value detected by the voltage detection module 1 is greater than or equal to the second overvoltage protection value, shutting down the circuit to be protected 10; when the voltage value detected by the voltage detection module 1 is greater than or equal to the first overvoltage protection value, and the voltage value detected by the voltage detection module 1 is less than the second overvoltage protection value, controlling the circuit to be protected 10 according to the change rate value.

[0049] Specifically, when the voltage value detected by the voltage detection module 1 is greater than or equal to the second overvoltage protection value, it means that the voltage value has exceeded the safety value. At this time, the circuit to be protected 10 is turned off to ensure the safety of the circuit. When the voltage value detected by the voltage detection module 1 is greater than or equal to the first overvoltage protection value, and the voltage value detected by the voltage detection module 1 is less than the second overvoltage protection value, at this time, although the voltage value is temporarily safe, it is also necessary to analyze the voltage value to clarify whether to intervene in the control, so as to ensure that the subsequent changes in the voltage value will not exceed the safety value.

[0050] See also Figure 4 In the control method of this embodiment, the method of controlling the circuit to be protected 10 according to the change rate value includes: when the change rate value is greater than or equal to the preset value, controlling the opening rate and opening time of the switch tube of the circuit to be protected 10 to increase, rectifying and storing energy; and continuing to detect the voltage value; when the change rate value is less than the preset value, the circuit to be protected 10 operates normally.

[0051] Specifically, the rate of change value means that although the voltage suddenly changes and the voltage change rate dv / dt ≧ the preset dv / dt, the bus voltage value actually sampled at this time has not reached the preset second overvoltage protection value. The voltage value at this time has not reached the level of damaging circuit components. However, since the voltage change rate is too high, allowing the bus voltage to continue to rise may cause the risk of overvoltage causing damage to circuit components. Therefore, the switch tube of the bridgeless PFC circuit is turned off, and only rectification is performed without energy storage, thereby reducing the bus voltage value.

[0052] Specifically, the rate of change value means that although the voltage changes suddenly, the voltage change rate dv / dt is less than the preset dv / dt, and the bus voltage value actually sampled at this time has not reached the preset second overvoltage protection value. The voltage value at this time has not reached the level of damaging circuit components, and the voltage change rate is not large. The voltage continues to rise within a certain period of time and will not cause the bus voltage value to be too high, so the unit is operating normally at this time.

[0053] In the control method of this embodiment, see Figure 4 The method for controlling the circuit to be protected 10 includes: setting a first undervoltage protection value; when the voltage value detected by the voltage detection module 1 is greater than the first undervoltage protection value, the circuit to be protected 10 works normally; when the voltage value is less than or equal to the first undervoltage protection value, controlling the circuit to be protected 10 to perform rectification and energy storage.

[0054] In the control method of this embodiment, see Figure 4 The method for controlling the circuit to be protected 10 includes: setting a second under-voltage protection value; when the voltage value detected by the voltage detection module 1 is greater than the second under-voltage protection value, the circuit to be protected 10 works normally; when the voltage value is less than or equal to the second under-voltage protection value, controlling the circuit to be protected 10 to perform under-voltage protection.

[0055] The working principle of the control method of this embodiment is as follows:

[0056] The bridgeless PFC circuit has a boost function. Different output voltages can be obtained by controlling the turn-on rate of the switch tube. Based on this characteristic, the bridgeless PFC circuit is protected under voltage fluctuations.

[0057] When it is detected that the voltage change rate is ≧ the preset dv / dt (i.e., the voltage change rate value), and the preset first overvoltage protection value < voltage value < preset second overvoltage protection value, the DSP circuit can control the drive circuit to turn off the switch tube of the bridgeless PFC circuit, so that the bridgeless PFC circuit only performs rectification without storing energy, thereby reducing the bus voltage and achieving protection of the bridgeless PFC circuit under high voltage fluctuations.

[0058] When it is detected that the voltage value is ≧ the preset second overvoltage protection value, it means that the high voltage under the voltage fluctuation has reached the upper limit of the bridgeless PFC circuit. Overvoltage protection should be performed immediately and the unit should be powered off and shut down.

[0059] When it is detected that the voltage value is ≤ the preset undervoltage protection value, the DSP circuit can control the drive circuit to increase the opening rate and opening time of the switch tube of the bridgeless PFC circuit, and perform rectification and energy storage operations, thereby increasing the bus voltage and reaching the operating voltage at which the unit can operate normally under low voltage with voltage fluctuations.

[0060] When it is detected that the voltage value is ≤ the preset second undervoltage protection value, it means that the low voltage of the voltage fluctuation can no longer reach the working voltage for the normal operation of the unit. Undervoltage protection should be performed immediately and the unit should be powered off and shut down.

[0061] The process of the control method of this embodiment is as follows:

[0062] See Figure 1 When the air-conditioning unit is running, the bus voltage value is continuously detected through the voltage detection module. When the voltage value is ≧ the preset first overvoltage protection value, the voltage change rate dv / dt is detected at the same time, and the next step of judgment is performed.

[0063] If the voltage value is ≧ the preset second overvoltage protection value, overvoltage protection is performed regardless of whether the voltage change rate is ≧ the preset dv / dt;

[0064] If the voltage change rate is ≧ the preset dv / dt, and the voltage value is less than the preset second overvoltage protection value, the DSP circuit controls the bridgeless PFC circuit to only rectify without energy storage, and continuously perform voltage detection;

[0065] If the voltage change rate is less than the preset dv / dt, and the voltage value is less than the preset second overvoltage protection value, the unit will operate normally and continue to perform voltage detection;

[0066] If the voltage value is greater than the preset undervoltage protection value, the unit operates normally and continues to perform voltage detection.

[0067] If the voltage value is less than or equal to the preset undervoltage protection value, the DSP circuit controls the PFC circuit to perform rectification and energy storage speed regulation, and then proceeds to the next step of judgment.

[0068] If the voltage value is ≤ the preset second undervoltage protection value, undervoltage protection is performed;

[0069] If the voltage value is greater than the preset second undervoltage protection value, the unit operates normally and continues to perform voltage detection.

[0070] The structure of the protection structure of this embodiment is as follows:

[0071] See Figure 1 The working circuit is mainly composed of a protection module 5, a bridgeless PFC module, a voltage detection module 1, a delay module 7, a subtraction module 2, a division module 3, an amplification module 6, a DSP circuit (ie, a control module 4), and a driving circuit.

[0072] The protection module 5 is composed of a switch K and a varistor RV1.

[0073] When the unit operates normally, the DSP circuit controls switch K to close.

[0074] When the unit detects an undervoltage fault or an overvoltage fault, the DSP circuit controls the switch K to disconnect, causing the unit to shut down.

[0075] The voltage detection module 1 detects the bus voltage value in real time, and its output value is Ubus=bus voltage value*(R44 / R41+R42+R43+R44).

[0076] The voltage detection module 1 continuously detects the bus voltage and transmits the output value to the subtraction module 2.

[0077] Subtraction module 2 is composed of operational amplifier U1, resistors R11, R12, R13, and R14. Ubus is directly output as UA, that is, Ubus=UA. At the same time, Ubus is output as UB through delay module 7. UA and UB signals are transmitted to the U1 element of subtraction module 2. Let R11=R12, R13=R14, then the output of subtraction module 2 is Uout1=UA-UB. The bus voltage output value Ubus is directly output as UA, and is output as UB after delay module 7. Therefore, this step can calculate the dv in the voltage change rate dv / dt, that is, the voltage difference at different times, and its output is Uout1=UA-UB.

[0078] The division module 3 is composed of an analog multiplier U2, an operational amplifier U3, and resistors R21, R22, R23, R24, and R25. The output signal Uout1 of the subtraction module 2 is transmitted to the U2 element, and the voltage is divided by R23 and R24 to output UC, which is used as the reference voltage of the voltage change rate. UC=VCC2*(R24 / R23+R24), and the UC signal is transmitted to the operational amplifier U3. The output Uout2 of the division module 3 is constructed as -(R22 / k*R21)*(UC / Uout1), where k is the product coefficient.

[0079] Since the delay time t is consistent after the output of the delay module 7, it can be canceled in the calculation. The reference voltage UC is used as the dt in the voltage change rate dv / dt. Since dt is the time difference and the delay time t is consistent, the reference voltage UC is built in the circuit to replace the delay time t. In this step, the voltage change rate dv / dt has been preliminarily obtained. That is, the output of the division module 3 is Uout2 = -(R22 / k*R21)*(UC / Uout1).

[0080] The amplification module 6 is composed of an operational amplifier U4, resistors R31 and R32. The output signal Uout2 of the division module 3 is transmitted to the operational amplifier U4, and the output Uout3 of the amplification module 6 is Uout2*(R31+R32) / R32.

[0081] Since the output voltage of the voltage change rate is small, the output of the division module 3 is amplified by the amplifier module 6. The amplification factor can be selected according to the actual needs by selecting the resistance values ​​of resistors R31 and R32. The output of the amplifier module 6 is Uout3 = Uout2*(R31+R32) / R32.

[0082] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0083] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and this embodiment will not be described in detail here.

[0084] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0085] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0086] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A protective structure, characterized in that: include: A voltage detection module (1) is used to detect a first voltage value of the circuit to be protected when it is at a first moment; A delay module (7), used for obtaining a second voltage value when the circuit to be protected is at a second moment; A subtraction module (2), the subtraction module (2) being used to calculate a difference between the first voltage value and the second voltage value; A division module (3), the division module (3) being used for dividing the difference value calculated by the subtraction module (2) by the time difference between the second moment and the first moment, so as to output a change rate value; A control module (4), wherein the control module (4) controls the circuit to be protected (10) according to the change rate value.

2. The protective structure according to claim 1, characterized in that: The protection structure comprises a protection module (5); the protection module (5) comprises a switch K and a varistor RV1 connected to the circuit to be protected (10).

3. The protective structure according to claim 1, characterized in that: The voltage detection module (1) comprises: A first resistor (11) and a second resistor (12), wherein the first resistor (11) and the second resistor (12) are both connected to the circuit to be protected (10), and the subtraction module (2) is connected to a circuit located between the first resistor (11) and the second resistor (12).

4. The protective structure according to claim 3, characterized in that: The subtraction module (2) comprises: An operational amplifier U1, wherein the positive input terminal of the operational amplifier U1 is connected to the circuit between the first resistor (11) and the second resistor (12), and the negative input terminal of the operational amplifier U1 is connected to the delay module (7) to receive the first voltage value and the second voltage value respectively; and the output terminal of the operational amplifier U1 is connected to the division module (3).

5. The protective structure according to claim 4, characterized in that: The subtraction module (2) comprises: A first circuit (21) connected to the positive input terminal of the operational amplifier U1; the first circuit (21) is connected to the circuit between the first resistor (11) and the second resistor (12); A second circuit (22) connected to the reverse input terminal of the operational amplifier U1; wherein the delay module (7) is arranged on the second circuit to delay the reverse input terminal of the operational amplifier U1 to the voltage detection module.

6. The protective structure according to claim 5, characterized in that: The division module (3) comprises: Analog multiplier U2; An operational amplifier U3, wherein the operational amplifier U3 is connected to the analog multiplier U2, the output end of the analog multiplier U2 is connected to the inverting input end of the operational amplifier U3, the output end of the subtraction module (2) is connected to an input end of the analog multiplier U2, and the other input end of the analog multiplier U2 is connected to the output end of the operational amplifier U3.

7. The protective structure according to claim 6, characterized in that: The protection structure further comprises an amplification module (6), wherein the amplification module (6) comprises an operational amplifier U4; the positive input terminal of the operational amplifier U4 is connected to the output terminal of the operational amplifier U3, and the output terminal of the operational amplifier U4 is connected to the control module (4).

8. The protective structure according to any one of claims 1 to 7, characterized in that: The control module (4) is connected to the voltage detection module (1).

9. An air conditioner, comprising a protective structure, characterized in that: The protective structure is the protective structure according to any one of claims 1 to 8.

10. A control method, applicable to the protective structure according to any one of claims 1 to 8, characterized in that: The control method comprises: The voltage detection module (1) detects the voltage value of the circuit to be protected (10); The subtraction module (2) collects the first voltage value and the second voltage value detected by the voltage detection module (1); wherein the first voltage value is the voltage value collected at a first moment, and the second voltage value is the voltage value collected at a second moment; the second moment is a moment after a delay of a period of time from the first moment; the subtraction module (2) calculates the difference between the first voltage value and the second voltage value; A division module (3) divides the difference value calculated by the subtraction module (2) by the time difference between the second moment and the first moment to output a change rate value; The control module (4) controls the circuit to be protected (10) according to the change rate value.

11. The control method according to claim 10, characterized in that: The method for controlling the circuit to be protected (10) comprises: Setting a first overvoltage protection value and a second overvoltage protection value; wherein the first overvoltage protection value is less than the second overvoltage protection value; When the voltage value detected by the voltage detection module (1) is greater than or equal to a second overvoltage protection value, the circuit to be protected (10) is turned off; When the voltage value detected by the voltage detection module (1) is greater than or equal to the first overvoltage protection value, and the voltage value detected by the voltage detection module (1) is less than the second overvoltage protection value, the circuit to be protected (10) is controlled according to the change rate value.

12. The control method according to claim 10, characterized in that: The method for controlling the circuit to be protected (10) according to the change rate value comprises: When the change rate value is greater than or equal to a preset value, the circuit to be protected (10) is controlled to only perform rectification without performing energy storage; and the voltage value is continuously detected; When the change rate value is less than the preset value, the circuit to be protected (10) operates normally.

13. The control method according to claim 10, characterized in that: The method for controlling the circuit to be protected (10) comprises: A first undervoltage protection value is set; when the voltage value detected by the voltage detection module (1) is greater than the first undervoltage protection value, the circuit to be protected (10) operates normally; when the voltage value is less than or equal to the first undervoltage protection value, the switching rate and switching time of the switch tube of the circuit to be protected (10) are controlled to increase, and rectification and energy storage are performed.

14. The control method according to claim 10, characterized in that: The method for controlling the circuit to be protected (10) comprises: A second undervoltage protection value is set; when the voltage value detected by the voltage detection module (1) is greater than the second undervoltage protection value, the circuit to be protected (10) operates normally; when the voltage value is less than or equal to the second undervoltage protection value, the circuit to be protected (10) is controlled to perform undervoltage protection.

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