Overcurrent protection circuit based on inverter circuit and inverter

Abstract

The utility model discloses an over-current protection circuit based on an inverter circuit and an inverter. The overcurrent protection circuit comprises a comparison branch, a controller and a signal combination branch. The comparison branch outputs a first comparison signal based on a comparison result of an absolute value of a first voltage corresponding to the output current and a first preset voltage value. When the absolute value of the first voltage is larger than or equal to a first preset voltage value, the first comparison signal is a first level, and when the absolute value of the first voltage is smaller than the first preset voltage value, the first comparison signal is a second level. The controller outputs a first driving signal. And the signal combination branch outputs a second driving signal to drive a switching tube in the inverter circuit based on the first driving signal and the first comparison signal. When the first comparison signal is the second level, the second driving signal is the same as the first driving signal, and when the first comparison signal is the first level, the second driving signal drives a switching tube in the inverter circuit to be kept switched off. In this way, the response time of over-current protection can be shortened.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to an overcurrent protection circuit and an inverter based on an inverter circuit. Background Art

[0002] In the field of switching power supplies, an inverter is an electronic device that converts direct current into alternating current (220VAC). The inverter consists of an inverter circuit, a controller, and other auxiliary circuits (such as a filter circuit). When the inverter is running, if an overcurrent fault occurs in the inverter circuit, the overcurrent protection must respond quickly and reliably to avoid damage to the components in the inverter.

[0003] At present, the overcurrent signal is first sent to the controller through the feedback circuit. After the controller processes the overcurrent signal, it stops outputting the driving signal for the switch tube in the control inverter. This process requires the controller software to process the overcurrent signal. The overall response time is relatively long. Utility Model Content

[0004] The present application aims to provide an overcurrent protection circuit and an inverter based on an inverter circuit, and the present application can speed up the response of the overcurrent protection.

[0005] To achieve the above objectives, in a first aspect, the present application provides an overcurrent protection circuit based on an inverter circuit, comprising:

[0006] a comparison branch, the comparison branch being connected to the inverter circuit and inputting an output current of the inverter circuit, the comparison branch being used to output a first comparison signal based on a comparison result between an absolute value of a first voltage corresponding to the output current and a first preset voltage value, wherein the first comparison signal is at a first level when the absolute value of the first voltage is greater than or equal to the first preset voltage value, and the first comparison signal is at a second level when the absolute value of the first voltage is less than the first preset voltage value;

[0007] A controller, the controller being used to output a first driving signal to drive a switch in the inverter circuit to turn on or off;

[0008] A signal combination branch, wherein the signal combination branch is respectively connected to the comparison branch, the controller and the inverter circuit, and the signal combination branch is used to output a second drive signal based on a result of combining the first drive signal and the first comparison signal to drive the switch tube in the inverter circuit to turn on or off, wherein when the first comparison signal is the second level, the second drive signal is the same as the first drive signal, and when the first comparison signal is the first level, the second drive signal drives the switch tube in the inverter circuit to remain turned off.

[0009] In an optional manner, the comparison branch further includes a first comparison module and a second comparison module, and the first comparison module and the second comparison module are both connected to the inverter circuit and the signal combination branch;

[0010] The first comparison module inputs the first preset voltage value, and the first comparison module is used to output a second comparison signal based on a comparison result between the first voltage and the first preset voltage value, wherein when the first voltage is less than the first preset voltage value, the second comparison signal is the second level, and when the first voltage is greater than or equal to the first preset voltage value, the second comparison signal is the first level;

[0011] The second comparison module inputs the negative value of the first preset voltage value, and the second comparison module is used to output a third comparison signal based on the comparison result of the first voltage and the negative value of the first preset voltage value, wherein when the first voltage is greater than the negative value of the first preset voltage value, the second comparison signal is the second level, and when the first voltage is less than or equal to the negative value of the first preset voltage value, the second comparison signal is the first level;

[0012] The first comparison signal is obtained by summing the second comparison signal and the third comparison signal, and when the second comparison signal and the third comparison signal are both at the second level, the first comparison signal is at the second level, and when one of the second comparison signal and the third comparison signal is at the first level, the first comparison signal is at the first level.

[0013] In an optional manner, the first comparison module includes a first resistor, a second resistor, a third resistor, a first capacitor and a first comparator;

[0014] The first end of the first resistor is connected to the inverter circuit, the second end of the first resistor is respectively connected to the first end of the first capacitor and the inverting input end of the first comparator, the first end of the second resistor inputs a second preset voltage value, the second end of the second resistor is respectively connected to the first end of the third resistor and the non-inverting input end of the first comparator, the output end of the first comparator outputs the second comparison signal, and the second end of the first capacitor and the second end of the third resistor are both grounded.

[0015] In an optional manner, the second comparison module includes a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a second comparator;

[0016] The first end of the fourth resistor is connected to the inverter circuit, the second end of the fourth resistor is respectively connected to the first end of the seventh resistor and the non-inverting input end of the second comparator, the first end of the fifth resistor inputs the negative value of the second preset voltage value, the second end of the fifth resistor is respectively connected to the inverting input end of the second comparator and the first end of the sixth resistor, the second end of the sixth resistor is grounded, the output end of the second comparator outputs the third comparison signal, and the second end of the seventh resistor inputs the first comparison signal.

[0017] In an optional manner, the comparison branch further includes an eighth resistor and a ninth resistor;

[0018] The first end of the eighth resistor is connected to the second power supply, the second end of the eighth resistor is respectively connected to the first end of the ninth resistor, the first comparison module and the second comparison module, and the second end of the ninth resistor outputs the first comparison signal.

[0019] In an optional manner, the signal combination branch includes AND gates corresponding one-to-one to the switch tubes in the inverter circuit;

[0020] The first input terminal of the AND gate inputs the first driving signal, the second input terminal of the AND gate inputs a signal obtained by summing the first driving signal and the first comparison signal, and the output terminal of the AND gate outputs the second driving signal.

[0021] In an optional manner, the signal combination branch further includes a current limiting resistor, a pull-down resistor and a diode corresponding one-to-one to the AND gate;

[0022] The first end of the current limiting resistor inputs the first driving signal, the second end of the current limiting resistor is respectively connected to the second input end of the AND gate and the anode of the diode, the cathode of the diode inputs the first comparison signal, and the pull-down resistor is connected between the output end of the AND gate and the ground.

[0023] In an optional manner, the overcurrent protection circuit further includes a first isolation branch and a second isolation branch;

[0024] The first isolation branch is connected between the first power supply and the second isolation branch, and the first isolation branch is used to supply power to the second isolation branch based on the isolated first power supply;

[0025] The second isolation branch is connected between the signal combination branch and the inverter circuit, and is used to isolate the second drive signal and then output a third drive signal to drive the switch tube in the inverter circuit to turn on or off.

[0026] In an optional manner, the first isolation branch includes a pulse transformer, and the second isolation branch includes an optocoupler.

[0027] In a second aspect, the present application provides an inverter, including an inverter circuit and an overcurrent protection circuit based on the inverter circuit as described above.

[0028] The beneficial effect of the present application is that the overcurrent protection circuit based on the inverter circuit provided by the present application includes a comparison branch, a controller and a signal combination branch. When the absolute value of the first voltage corresponding to the output current is greater than or equal to the first preset voltage value, an overcurrent may occur. At this time, the comparison branch outputs a first comparison signal of a first level. Then, the signal combination branch drives the switch tube in the inverter circuit to remain turned off based on the second drive signal output by the first comparison signal and the first drive signal output by the controller, thereby achieving the purpose of overcurrent protection. Moreover, when an overcurrent occurs, the switch tube in the inverter circuit can be quickly turned off by hardware, and the response speed will be faster than the processing speed of the controller in the related art, thereby reducing the response time of the overcurrent protection. Secondly, by configuring the comparison branch to use the absolute value of the first voltage as a comparison parameter, it is also possible to process the AC current with a negative current to achieve overcurrent protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0030] Figure 1 A schematic diagram of the structure of an overcurrent protection circuit provided in Embodiment 1 of the present application;

[0031] Figure 2 A schematic diagram of the structure of an overcurrent protection circuit provided in Embodiment 2 of the present application;

[0032] Figure 3 A schematic diagram of the structure of an overcurrent protection circuit provided in Embodiment 3 of the present application;

[0033] Figure 4 A schematic diagram of the circuit structure of the overcurrent protection circuit provided in Example 1 of the present application. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, 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 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 are within the scope of protection of this application.

[0035] Please refer to Figure 1 , Figure 1 The overcurrent protection circuit based on the inverter circuit provided in the embodiment of the present application includes a comparison branch 10 , a controller 20 and a signal combination branch 30 .

[0036] The comparison branch 10 is connected to the inverter circuit 200. The signal combination branch 30 is connected to the comparison branch 10, the controller 20 and the inverter circuit 200 respectively.

[0037] Specifically, the comparison branch 10 inputs the output current I1 of the inverter circuit 200, and the comparison branch 10 is used to output a first comparison signal S1 based on the comparison result of the absolute value of the first voltage V1 corresponding to the output current I1 and the first preset voltage value. Wherein, when the absolute value of the first voltage V1 is greater than or equal to the first preset voltage value, the first comparison signal S1 is a first level, and when the absolute value of the first voltage V1 is less than the first preset voltage value, the first comparison signal S1 is a second level. The controller 20 is used to output a first drive signal for driving the switch tube in the inverter circuit 200 to turn on or off. The signal combination branch 30 is used to output a second drive signal based on the result of combining the first drive signal with the first comparison signal to drive the switch tube in the inverter circuit 200 to turn on or off. Wherein, when the first comparison signal S1 is the second level, the second drive signal is the same as the first drive signal, and when the first comparison signal S1 is the first level, the second drive signal drives the switch tube in the inverter circuit to remain turned off.

[0038] The first level and the second level are different levels. When the first level is a high level, the second level is a low level; when the first level is a low level, the second level is a high level. The first preset voltage value is a pre-set voltage value, which can be set according to actual application conditions, and the embodiment of the present application does not specifically limit this.

[0039] In the embodiment of the present application, each driving signal is a pulse width modulation (PWM) signal. For example, the first driving signal and the second driving signal are both PWM signals.

[0040] Specifically, when the absolute value of the first voltage V1 corresponding to the output current I1 is less than the first preset voltage value, it can be determined that an overcurrent abnormality occurs at this time. At this time, the first comparison signal S1 output by the comparison branch 10 is at the second level. Then, the second drive signal output by the signal combination branch 30 based on the first comparison signal S1 and the first drive signal is the same as the first drive signal, that is, the level of the second drive signal is consistent with the first drive signal. The duration of the switch tube in the inverter circuit 200 being turned on and off is determined by the second drive signal, that is, by the first drive signal. The inverter circuit 200 operates normally.

[0041] When the absolute value of the first voltage V1 corresponding to the output current I1 is greater than or equal to the first preset voltage value, an overcurrent may occur. At this time, the comparison branch 10 outputs the first comparison signal S1 as a first level. Then, the second drive signal output by the signal combination branch 30 based on the first comparison signal S1 and the first drive signal is used to drive the switch tube in the inverter circuit 200 to remain turned off, thereby achieving the purpose of overcurrent protection. It can be seen that when an overcurrent occurs, the switch tube in the inverter circuit 200 can be quickly turned off by hardware, and the response speed of the present application is faster than the processing speed of the controller in the related art (the controller at least needs to execute the process of determining that an overcurrent has occurred according to the overcurrent signal, and then further execute the process of stopping the output of the drive signal of the control switch tube). Thus, the response time of the overcurrent protection can be reduced. Secondly, by configuring the comparison branch 10 to use the absolute value of the first voltage V1 as a comparison parameter, it is also possible to process the AC current with a negative current to achieve overcurrent protection when the negative current is too large.

[0042] In one embodiment, if Figure 2 As shown, the comparison branch 10 further includes a first comparison module 11 and a second comparison module 12 . Both the first comparison module 11 and the second comparison module 12 are connected to the inverter circuit 200 and the signal combination branch 30 .

[0043] The first comparison module 11 inputs a first preset voltage value (denoted as VR1), and the first comparison module 11 is used to output a second comparison signal S2 based on the comparison result between the first voltage V1 and the first preset voltage value VR1. When the first voltage V1 is less than the first preset voltage value VR1, the second comparison signal S2 is at a second level, and when the first voltage V1 is greater than or equal to the first preset voltage value VR1, the second comparison signal S2 is at a first level. The second comparison module 12 inputs a negative value of the first preset voltage value (i.e. -VR1), and the second comparison module 12 is used to output a third comparison signal S3 based on the comparison result between the first voltage V1 and the negative value -VR1 of the first preset voltage value. When the first voltage V1 is greater than the negative value -VR1 of the first preset voltage value, the second comparison signal S2 is at a second level, and when the first voltage V1 is less than or equal to the negative value -VR1 of the first preset voltage value, the second comparison signal S2 is at a first level.

[0044] The first comparison signal S1 is obtained by summing the second comparison signal S2 and the third comparison signal S3. Specifically, when the second comparison signal S2 and the third comparison signal S3 are both at the second level, the first comparison signal S1 is at the second level; when one of the second comparison signal S2 and the third comparison signal S3 is at the first level, the first comparison signal S1 is at the first level.

[0045] In this embodiment, by setting the first comparison module 11 and the second comparison module 12 to process the positive current and the negative current respectively, the overcurrent protection process for the AC current can be realized. Wherein, if the first preset voltage value is recorded as VR1, the negative value of the first preset voltage value is -VR1. Then, when -VR1<V1<VR1, the second comparison signal S2 and the third comparison signal S3 are both at the second level, and the first comparison signal S1 is at the second level; when V1≥VR1, the second comparison signal S2 is at the first level, the third comparison signal S3 is at the second level, and the first comparison signal S1 is at the first level; when V1≤-VR1, the second comparison signal S2 is at the second level, the third comparison signal S3 is at the first level, and the first comparison signal S1 is at the first level.

[0046] In one embodiment, if Figure 3 As shown, the overcurrent protection circuit 100 further includes a first isolation branch 40 and a second isolation branch 50 .

[0047] The first isolation branch 40 is connected between the first power supply VC1 and the second isolation branch 50, and the first isolation branch 40 is used to supply power to the second isolation branch 40 based on the isolated first power supply VC1. The second isolation branch 50 is connected between the signal combination branch 30 and the inverter circuit 200, and the second isolation branch 50 is used to isolate the second drive signal and output a third drive signal to drive the switch tube in the inverter circuit 200 to turn on or off.

[0048] Specifically, for the switch tube in the inverter circuit 200, the working process of providing a driving signal (i.e., a PWM signal) for it needs to be completed by an independent system, and this system that provides the driving signal belongs to the low-voltage weak-current signal circuit (including the overcurrent protection circuit in the embodiment of the present application). For safety and to reduce the interference of the high-voltage strong-electric partial circuit (such as the partial circuit for outputting the first power supply VC1) to the low-voltage weak-electric signal circuit, electrical isolation is required between the two. This embodiment achieves isolation between the high-voltage strong-electric partial circuit and the low-voltage weak-electric signal circuit by setting a first isolation branch 40 and a second isolation branch 50.

[0049] In some embodiments, the first isolation branch 10 includes a pulse transformer, and the second isolation branch 20 includes an optocoupler.

[0050] Among them, a pulse transformer is a device used to convert voltage or current signals into pulse form. It usually consists of one or more windings and an iron core, and changes the amplitude and waveform of the output signal by changing the frequency and duty cycle of the input signal. Pulse transformers can often be used to isolate and match signals between different circuits.

[0051] Optocoupler is an electronic component, also called photocoupler or photoisolator, which is used to isolate the input and output circuits and transmit data or control signals through optical signals. Optocouplers are usually composed of a light-emitting diode and a photoresistor or photodiode. Optocouplers can generate light signals through light-emitting diodes and then receive light signals through photoresistors or photodiodes, thereby isolating input and output signals.

[0052] Please refer to Figure 4 , Figure 4 An example is shown with Figure 3 A circuit structure corresponding to the structure shown in FIG. Figure 4 In the embodiment, the inverter circuit 200 includes four switch tubes (respectively, the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4) as an example. The first current I1 is the current flowing through the inductor L1. At the same time, the embodiment also takes the first level as a low level and the second level as a high level as an example.

[0053] In one embodiment, if Figure 4 As shown, the first comparison module 11 includes a first resistor R1 , a second resistor R2 , a third resistor R3 , a first capacitor C1 and a first comparator U1 .

[0054] Among them, the first end of the first resistor R1 is connected to the inverter circuit 200 to input the first current I1, the second end of the first resistor R1 is respectively connected to the first end of the first capacitor C1 and the inverting input end of the first comparator U1, the first end of the second resistor R2 inputs the second preset voltage value VR2, the second end of the second resistor R2 is respectively connected to the first end of the third resistor R3 and the non-inverting input end of the first comparator U1, the output end of the first comparator U1 outputs the second comparison signal S2, and the second end of the first capacitor C1 and the second end of the third resistor R3 are both grounded GND.

[0055] Specifically, the first current I1 is converted into a first voltage V1 after integration of the first resistor R1 and the first capacitor C1, and the first voltage V1 is input to the inverting input terminal of the first comparator U1. The second preset voltage value VR2 is a preset voltage value, which can be set based on actual application conditions, and the embodiment of the present application does not impose specific restrictions on this. The second preset voltage value VR2 is generated by the voltage division of the second resistor R2 and the third resistor R3 to generate the first preset voltage value VR1, and the first preset voltage value VR1 is input to the non-inverting input terminal of the first comparator U1.

[0056] Subsequently, when the first voltage V1 is greater than or equal to the first preset voltage value VR1, the second comparison signal output by the first comparator U1 is a low level (i.e., the first level); when the first voltage V1 is less than the first preset voltage value VR1, the second comparison signal output by the first comparator U1 is a high level (i.e., the second level).

[0057] In one embodiment, the second comparison module 12 includes a fourth resistor R4 , a fifth resistor R5 , a sixth resistor R6 , a seventh resistor R7 and a second comparator U2 .

[0058] Among them, the first end of the fourth resistor R4 is connected to the inverter circuit 200 to input the first current I1, the second end of the fourth resistor R4 is respectively connected to the first end of the seventh resistor R7 and the non-inverting input end of the second comparator U2, the first end of the fifth resistor R5 inputs the negative value of the second preset voltage value -VR2, the second end of the fifth resistor R5 is respectively connected to the inverting input end of the second comparator U2 and the first end of the sixth resistor R6, the second end of the sixth resistor R6 is grounded GND, the output end of the second comparator U2 outputs the third comparison signal S3, and the second end of the seventh resistor R7 inputs the first comparison signal S1.

[0059] Specifically, the first current I1 flows through the fourth resistor R4 to generate a first voltage V1, and the first voltage V1 is input to the non-inverting input terminal of the second comparator U2. The second preset voltage value VR2 is divided by the fifth resistor R5 and the sixth resistor R6 to generate a negative value -VR1 of the first preset voltage value, and the negative value -VR1 of the first preset voltage value is input to the inverting input terminal of the first comparator U1.

[0060] Subsequently, when the first voltage V1 is greater than the negative value of the first preset voltage value -VR1, the third comparison signal output by the second comparator U2 is a high level (i.e., the second level); when the first voltage V1 is less than or equal to the negative value of the first preset voltage value -VR1, the third comparison signal output by the second comparator U2 is a low level (i.e., the first level).

[0061] In one embodiment, the comparison branch 10 further includes an eighth resistor R8 and a ninth resistor R9.

[0062] The first end of the eighth resistor R8 is connected to the second power supply VC2, the second end of the eighth resistor R8 is respectively connected to the first end of the ninth resistor R9, the first comparison module 11 and the second comparison module 12, and the second end of the ninth resistor R9 outputs the first comparison signal S1.

[0063] Specifically, the eighth resistor R8 is a pull-up resistor, which strengthens the voltage corresponding to the high level of the first comparison signal S1 after the second comparison signal S2 and the third comparison signal S3 are summed through the second power supply VC2, so as to improve the anti-interference ability of the first comparison signal S1, thereby improving the reliability of the entire overcurrent protection circuit 100.

[0064] The ninth resistor R9 is a current limiting resistor.

[0065] In one embodiment, the signal combination branch includes AND gates corresponding one-to-one to the switch tubes in the inverter circuit.

[0066] The first input terminal of the AND gate inputs the first driving signal, the second input terminal of the AND gate inputs the signal obtained by summing the first driving signal and the first comparison signal, and the output terminal of the AND gate outputs the second driving signal.

[0067] In one embodiment, the signal combination branch further includes a current limiting resistor, a pull-down resistor, and a diode corresponding one-to-one to the AND gate.

[0068] The first end of the current limiting resistor inputs the first driving signal, the second end of the current limiting resistor is respectively connected to the second input end of the AND gate and the anode of the diode, the cathode of the diode inputs the first comparison signal, and the pull-down resistor is connected between the output end of the AND gate and the ground.

[0069] by Figure 4For example. Since in this embodiment, the inverter circuit 200 includes four switch tubes, four AND gates are set accordingly. The four AND gates are respectively the first AND gate AND1, the second AND gate AND2, the third AND gate AND3 and the fourth AND gate AND4. The four current limiting resistors are respectively the first current limiting resistor RA1, the second current limiting resistor RA2, the third current limiting resistor RA3 and the fourth current limiting resistor RA4. The four pull-down resistors are respectively the first pull-down resistor RB1, the second pull-down resistor RB2, the third pull-down resistor RB3 and the fourth pull-down resistor RB4. The four diodes are respectively the first diode D1, the second diode D2, the third diode D3 and the fourth diode D4. In some embodiments, each diode can be selected from Schottky diodes.

[0070] The first driving signal output by the controller 20 includes four sub-signals, namely, the first driving sub-signal P11, the second driving sub-signal P12, the third driving sub-signal P13 and the fourth driving sub-signal P14. Similarly, the subsequent second driving signal also includes four sub-signals, namely, the fifth driving sub-signal P21, the sixth driving sub-signal P22, the seventh driving sub-signal P23 and the eighth driving sub-signal P24. The subsequent third driving signal also includes four sub-signals, namely, the ninth driving sub-signal P31, the tenth driving sub-signal P32, the tenth driving sub-signal P33 and the twelfth driving sub-signal P34.

[0071] When the first comparison signal S1 is at a high level, if the first driving sub-signal P11 is at a low level, the two input terminals of the first AND gate AN1 are both input with a low level, and the output terminal of the first AND gate AN1 outputs a low level, that is, the fifth driving sub-signal P21 is at a low level; if the first driving sub-signal P11 is at a high level, the two input terminals of the first AND gate AN1 are both input with a high level, and the output terminal of the first AND gate AN1 outputs a high level, that is, the fifth driving sub-signal P21 is at a high level. It can be seen that when the first comparison signal S1 is at a high level, the fifth driving sub-signal P21 is the same as the first driving sub-signal P11.

[0072] When the first comparison signal S1 is at a low level, no matter whether the first driving sub-signal P11 is at a high level or a low level, the second input terminal of the first AND gate AN1 maintains an input low level. The output terminal of the first AND gate AN1 also maintains an output low level. That is, the fifth driving sub-signal P21 is at a low level. It can be seen that when the first comparison signal S1 is at a low level, the fifth driving sub-signal P21 remains at a low level to drive the first switch tube Q1 to remain turned off.

[0073] The fifth drive sub-signal P21 is isolated by the second isolation branch 50 to generate a ninth drive sub-signal P31, and the ninth drive sub-signal P31 is input to the first switch tube Q1 through the resistor RC1 to drive the first switch tube Q1. Among them, the ninth drive sub-signal P31 has the same level as the fifth drive sub-signal P21. Furthermore, when an overcurrent abnormality occurs, since the first comparison signal S1 is at a low level, the fifth drive sub-signal P21 remains at a low level, the ninth drive sub-signal P31 also remains at a low level, and the first switch tube Q1 remains turned off, thereby realizing the overcurrent protection function. In addition, the above process quickly turns off the switch tube in the inverter circuit through hardware, and the response speed is faster than the processing speed of the controller in the related art, which is conducive to reducing the response time of the overcurrent protection.

[0074] In addition, the implementation process of the signal for driving the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 is similar to that of the first switch tube Q1, and the details can be referred to the detailed description of the first switch tube Q1, which will not be repeated here.

[0075] The embodiment of the present application further provides an inverter, which includes an inverter circuit and an overcurrent protection circuit 100 based on the inverter circuit in any embodiment of the present application.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present application as described above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An overcurrent protection circuit based on an inverter circuit, characterized in that: include: a comparison branch, the comparison branch being connected to the inverter circuit and inputting an output current of the inverter circuit, the comparison branch being used to output a first comparison signal based on a comparison result between an absolute value of a first voltage corresponding to the output current and a first preset voltage value, wherein the first comparison signal is at a first level when the absolute value of the first voltage is greater than or equal to the first preset voltage value, and the first comparison signal is at a second level when the absolute value of the first voltage is less than the first preset voltage value; A controller, the controller being used to output a first driving signal to drive a switch in the inverter circuit to turn on or off; A signal combination branch, wherein the signal combination branch is respectively connected to the comparison branch, the controller and the inverter circuit, and the signal combination branch is used to output a second drive signal based on a result of combining the first drive signal and the first comparison signal to drive the switch tube in the inverter circuit to turn on or off, wherein when the first comparison signal is the second level, the second drive signal is the same as the first drive signal, and when the first comparison signal is the first level, the second drive signal drives the switch tube in the inverter circuit to remain turned off.

2. The overcurrent protection circuit according to claim 1, characterized in that: The comparison branch further includes a first comparison module and a second comparison module, and the first comparison module and the second comparison module are both connected to the inverter circuit and the signal combination branch; The first comparison module inputs the first preset voltage value, and the first comparison module is used to output a second comparison signal based on a comparison result between the first voltage and the first preset voltage value, wherein when the first voltage is less than the first preset voltage value, the second comparison signal is the second level, and when the first voltage is greater than or equal to the first preset voltage value, the second comparison signal is the first level; The second comparison module inputs the negative value of the first preset voltage value, and the second comparison module is used to output a third comparison signal based on the comparison result of the first voltage and the negative value of the first preset voltage value, wherein when the first voltage is greater than the negative value of the first preset voltage value, the second comparison signal is the second level, and when the first voltage is less than or equal to the negative value of the first preset voltage value, the second comparison signal is the first level; The first comparison signal is obtained by summing the second comparison signal and the third comparison signal, and when the second comparison signal and the third comparison signal are both at the second level, the first comparison signal is at the second level, and when one of the second comparison signal and the third comparison signal is at the first level, the first comparison signal is at the first level.

3. The overcurrent protection circuit according to claim 2, characterized in that: The first comparison module includes a first resistor, a second resistor, a third resistor, a first capacitor and a first comparator; The first end of the first resistor is connected to the inverter circuit, the second end of the first resistor is respectively connected to the first end of the first capacitor and the inverting input end of the first comparator, the first end of the second resistor inputs a second preset voltage value, the second end of the second resistor is respectively connected to the first end of the third resistor and the non-inverting input end of the first comparator, the output end of the first comparator outputs the second comparison signal, and the second end of the first capacitor and the second end of the third resistor are both grounded.

4. The overcurrent protection circuit according to claim 2, characterized in that: The second comparison module includes a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a second comparator; The first end of the fourth resistor is connected to the inverter circuit, the second end of the fourth resistor is respectively connected to the first end of the seventh resistor and the non-inverting input end of the second comparator, the first end of the fifth resistor inputs a negative value of the second preset voltage value, the second end of the fifth resistor is respectively connected to the inverting input end of the second comparator and the first end of the sixth resistor, the second end of the sixth resistor is grounded, the output end of the second comparator outputs the third comparison signal, and the second end of the seventh resistor inputs the first comparison signal.

5. The overcurrent protection circuit according to claim 2, characterized in that: The comparison branch further includes an eighth resistor and a ninth resistor; The first end of the eighth resistor is connected to the second power supply, the second end of the eighth resistor is respectively connected to the first end of the ninth resistor, the first comparison module and the second comparison module, and the second end of the ninth resistor outputs the first comparison signal.

6. The overcurrent protection circuit according to claim 1, characterized in that: The signal combination branch includes AND gates corresponding one to one with the switch tubes in the inverter circuit; The first input terminal of the AND gate inputs the first driving signal, the second input terminal of the AND gate inputs a signal obtained by summing the first driving signal and the first comparison signal, and the output terminal of the AND gate outputs the second driving signal.

7. The overcurrent protection circuit according to claim 6, characterized in that: The signal combination branch also includes a current limiting resistor, a pull-down resistor and a diode corresponding to the AND gate one by one; The first end of the current limiting resistor inputs the first driving signal, the second end of the current limiting resistor is respectively connected to the second input end of the AND gate and the anode of the diode, the cathode of the diode inputs the first comparison signal, and the pull-down resistor is connected between the output end of the AND gate and the ground.

8. The overcurrent protection circuit according to claim 1, characterized in that: The overcurrent protection circuit also includes a first isolation branch and a second isolation branch; The first isolation branch is connected between the first power supply and the second isolation branch, and the first isolation branch is used to supply power to the second isolation branch based on the isolated first power supply; The second isolation branch is connected between the signal combination branch and the inverter circuit, and is used to isolate the second drive signal and then output a third drive signal to drive the switch tube in the inverter circuit to turn on or off.

9. The overcurrent protection circuit according to claim 8, characterized in that: The first isolation branch includes a pulse transformer, and the second isolation branch includes an optical coupler.

10. An inverter, characterized in that: It comprises an inverter circuit and an overcurrent protection circuit based on the inverter circuit as described in any one of claims 1 to 9.

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