Absorption circuit and inverter

Abstract

The embodiment of the utility model discloses an absorption circuit and an inverter. The absorption circuit comprises an absorption module, a switch module and an adjusting module. The first and second ends of the absorption module are respectively connected with the first ends of the first and second switching tubes, and the third end of the absorption module is connected with the input end of the transformer; the first end of the switch module is connected with the fourth end of the absorption module. The second end of the switch module is connected with the first pole plate of the first capacitor and the input end of the transformer. The first end of the adjusting module is connected with the first end of the switch module, the second end is connected with the controlled end of the switch module, the third end is connected with the controlled end of the first switch tube and the controlled end of the second switch tube, and the adjusting module controls on-off of the switch module according to the first control signal and the second control signal. The absorption circuit can absorb the peak voltage, so that the operation stability and reliability of the first switching tube and the second switching tube are ensured, energy recovery of the peak voltage is realized, and the overall conversion efficiency of the inverter is ensured.

Description

Technical Field

[0001] This application relates to the technical field of inverters, and particularly to a snubber circuit and an isolation chip. Background Art

[0002] Currently, isolation boost circuits usually include push-pull circuits, full-bridge circuits, and half-bridge circuits, etc. Among them, the power transistors in the push-pull circuit may generate relatively large peak voltages when conducting and turning off. When the peak voltage is too high, it will cause the power transistors to be damaged, affecting the normal use of the push-pull circuit. Summary of the Utility Model

[0003] Embodiments of this application provide a snubber circuit and an inverter, aiming to solve the problem that the switch tube is damaged due to too high peak voltage, affecting the normal use of the push-pull circuit.

[0004] In a first aspect, embodiments of this application provide a snubber circuit, including a snubber module, a switch module, and an adjustment module; the first end of the snubber module is connected to the first end of the first switch transistor and the first end of the transformer, the second end of the snubber module is connected to the first end of the second switch transistor and the second end of the transformer, and the third end of the snubber module is connected to the input end of the transformer; the first end of the switch module is connected to the fourth end of the snubber module, the second end of the switch module is connected to the first plate of the first capacitor and the input end of the transformer; the first end of the adjustment module is connected to the first end of the switch module, the second end of the adjustment module is connected to the controlled end of the switch module, and the third end of the adjustment module is connected to the controlled ends of the first switch transistor and the second switch transistor. The adjustment module is used to control the on / off of the switch module according to a first control signal or a second control signal.

[0005] In the above technical solution, when any one of the first switch transistor or the second switch transistor is turned off, the snubber module can absorb and store the corresponding generated peak voltage to avoid the problem that the first switch transistor or the second switch transistor is damaged and cannot be used normally due to too high peak voltage, thereby affecting the normal use of the inverter, ensuring the operation stability and reliability of the first switch transistor and the second switch transistor, and further ensuring the operation stability and reliability of the entire inverter. At the same time, the adjustment module can control the on / off of the switch module according to the first control signal or the second control signal, so that when the switch module is turned on, the peak voltage is fed back to the first capacitor to realize the energy recovery of the peak voltage, avoiding the problem that the peak voltage is consumed by other components, improving the power supply efficiency of the first capacitor, and thus ensuring the conversion efficiency of the entire inverter.

[0006] In combination with the first aspect, in some possible implementation manners, the adjustment module includes a second capacitor, a first resistor, and a second resistor; a first plate of the second capacitor is connected to a controlled end of the first switching transistor and a controlled end of the second switching transistor at a first node; one end of the first resistor is connected to a second plate of the second capacitor at a second node, and the other end of the first resistor is connected to a first end of the switching module; one end of the second resistor is connected to the first node, and the other end of the second resistor is connected to a controlled end of the switching module at a third node, and the third node is connected to the second node.

[0007] In combination with the first aspect, in some possible implementation manners, the switching module includes a P-type metal-oxide-semiconductor transistor, a source of the P-type metal-oxide-semiconductor transistor is connected to the other end of the first resistor, a drain of the P-type metal-oxide-semiconductor transistor is connected to a first plate of the first capacitor and an input end of a transformer, and a gate of the P-type metal-oxide-semiconductor transistor is connected to the third node; or, an N-type metal-oxide-semiconductor transistor, a drain of the N-type metal-oxide-semiconductor transistor is connected to the other end of the first resistor, a source of the N-type metal-oxide-semiconductor transistor is connected to a first plate of the first capacitor and an input end of the transformer, and a gate of the N-type metal-oxide-semiconductor transistor is connected to the third node.

[0008] In the above technical solution, when the switching module includes a P-type metal-oxide-semiconductor transistor, when the first control signal is at a low level, it will pull down the second capacitor and the second resistor to reduce the gate-source voltage of the P-type metal-oxide-semiconductor transistor, so that the P-type metal-oxide-semiconductor transistor is turned on, enabling the energy of the spike voltage stored in the third capacitor to charge the first capacitor, that is, the energy of the spike voltage stored in the third capacitor can flow back to the first capacitor, realizing the energy recovery of the spike voltage, avoiding the problem that the spike voltage is consumed by other components, improving the power supply efficiency of the first capacitor, and thus ensuring the overall conversion efficiency of the inverter. When the switching module includes an N-type metal-oxide-semiconductor transistor, when the first control signal is at a high level, it will raise the second capacitor and the second resistor to increase the gate-drain voltage of the N-type metal-oxide-semiconductor transistor, so that the N-type metal-oxide-semiconductor transistor is turned on, enabling the energy of the spike voltage stored in the third capacitor to charge the first capacitor, that is, the energy of the spike voltage stored in the third capacitor can flow back to the first capacitor, realizing the energy recovery of the spike voltage, avoiding the problem that the spike voltage is consumed by other components, improving the power supply efficiency of the first capacitor, and thus ensuring the overall conversion efficiency of the inverter.

[0009] In combination with the first aspect, in some possible implementation manners, the absorption circuit further includes an inductor and a first freewheeling diode; one end of the inductor is connected to the second end of the switching module, and the other end of the inductor is connected to the first plate of the first capacitor and the input end of the transformer; the positive electrode of the first freewheeling diode is connected to the first plate of the first capacitor and the input end of the transformer, and the negative electrode of the first freewheeling diode is connected to one end of the inductor and the second end of the switching module.

[0010] In combination with the first aspect, in some possible implementation manners, the absorption circuit further includes a filtering module, one end of the filtering module is connected to the other end of the inductor and the first plate of the first capacitor, and the other end of the filtering module is connected to the positive electrode of the first freewheeling diode and the input end of the transformer.

[0011] In combination with the first aspect, in some possible implementation manners, the absorption module includes a freewheeling unit and a third capacitor; the first input end of the freewheeling unit is connected to the first end of the first switching tube, and the second input end of the freewheeling unit is connected to the first end of the second switching tube; the first plate of the third capacitor is connected to the output end of the freewheeling unit and the first end of the switching module, and the second plate of the third capacitor is connected to the input end of the transformer.

[0012] In the above technical solution, when the first switching tube or the second switching tube is turned off, the peak voltage generated will charge the third capacitor through the freewheeling unit, so that the absorption module can absorb and store the peak voltage, thereby avoiding the problem that the first switching tube or the second switching tube is damaged and cannot be used normally due to too high peak voltage, which in turn affects the normal use of the inverter, and ensuring the operation stability and reliability of the first switching tube and the second switching tube, and further ensuring the operation stability and reliability of the overall inverter. At the same time, when the current flowing through the transformer coil disappears due to the turn-off of the first switching tube or the second switching tube, the induced electromotive force generated by the coil can do work through the freewheeling unit and be consumed, so as to avoid the problem that the induced electromotive force generated by the transformer coil generates a reverse voltage on the first switching tube or the second switching tube, resulting in damage to the first switching tube or the second switching tube, and further improving the operation stability and reliability of the first switching tube and the second switching tube, and further improving the operation stability and reliability of the overall inverter.

[0013] In combination with the first aspect, in some possible implementation manners, the freewheeling unit includes a second freewheeling diode and a third freewheeling diode; the positive electrode of the second freewheeling diode is connected to the first end of the first switching tube and the first end of the transformer, and the negative electrode of the second freewheeling diode is connected to the first plate of the third capacitor and the first end of the switching module; the positive electrode of the third freewheeling diode is connected to the first end of the second switching tube and the second end of the transformer, and the negative electrode of the third freewheeling diode is connected to the negative electrode of the second freewheeling diode, the first plate of the third capacitor and the first end of the switching module.

[0014] In combination with the first aspect, in some possible implementation manners, the absorption circuit further includes a driving module. The first end of the driving module is connected to the third end of the regulating module. The second end of the driving module is connected to the controlled end of the first switching tube. The third end of the driving module is connected to the controlled end of the second switching tube.

[0015] In combination with the first aspect, in some possible implementation manners, the driving module includes a first driving diode and a second driving diode. The positive electrode of the first driving diode is connected to the third end of the regulating module. The negative electrode of the first driving diode is connected to the controlled end of the first switching tube. The positive electrode of the second driving diode and the positive electrode of the first driving diode are connected to a fourth node at the third end of the regulating module. The negative electrode of the second driving diode is connected to the controlled end of the second switching tube.

[0016] In a second aspect, an embodiment of the present application provides an inverter, including the absorption circuit according to any optional manner of the first aspect and an isolation circuit. The isolation circuit includes a first capacitor, a transformer, a first switching tube, and a second switching tube. The first plate of the first capacitor is connected to the input end of the transformer. The controlled end of the first switching tube receives a first control signal. The first end of the first switching tube is connected to the first end of the transformer. The controlled end of the second switching tube receives a second control signal. The first end of the second switching tube is connected to the first end of the transformer. The second plate of the first capacitor, the second end of the first switching tube, and the second end of the second switching tube are grounded.

[0017] Based on the absorption circuit and the inverter provided by the present application, when any one of the first switching tube or the second switching tube is turned off, the corresponding generated spike voltage can be absorbed and stored to avoid the problem that the spike voltage is too high, causing the first switching tube or the second switching tube to be damaged and unable to be used normally, thereby affecting the normal use of the inverter. This ensures the operating stability and reliability of the first switching tube and the second switching tube, and further ensures the overall operating stability and reliability of the inverter. At the same time, the regulating module can control the on / off of the switching module according to the first control signal or the second control signal. When the switching module is turned on, the spike voltage is fed back to the first capacitor to realize the energy recovery of the spike voltage, avoiding the problem that the spike voltage is consumed by other components, improving the power supply efficiency of the first capacitor, and thus ensuring the overall conversion efficiency of the inverter. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 It is a schematic diagram of the circuit structure of an inverter provided by an embodiment of the present application;

[0020] Figure 2 It is another schematic diagram of the circuit structure of an inverter provided by an embodiment of the present application;

[0021] Figure 3 It is another schematic diagram of the circuit structure of an inverter provided by an embodiment of the present application;

[0022] Figure 4 It is still another schematic diagram of the circuit structure of an inverter provided by an embodiment of the present application;

[0023] Figure 5 It is still another schematic diagram of the circuit structure of an inverter provided by an embodiment of the present application;

[0024] Figure 6 It is still another schematic diagram of the circuit structure of an inverter provided by an embodiment of the present application;

[0025] Figure 7 It is still another schematic diagram of the circuit structure of an inverter provided by an embodiment of the present application.

[0026] Reference numerals:

[0027] 1. Isolation circuit; 2. Absorption circuit; 21. Absorption module; 211. Freewheeling unit; 22. Switch module; 23. Regulation module; 24. Filter module; 25. Drive module;

[0028] PWMA, First control signal; PWMB, Second control signal; C1, First capacitor; C2, Second capacitor; C3, Third capacitor; T, Transformer; Q1, First switching tube; Q2, Second switching tube; R1, First resistor; R2, Second resistor; PM, PMOS transistor; NM, NMOS transistor; D1, First freewheeling diode; D2, Second freewheeling diode; D3, Third freewheeling diode; D4, First drive diode; D5, Second drive diode; L, Inductor; A, First node; B, Second node; C, Third node; D, Fourth node. Detailed implementation manners

[0029] To make the objectives, technical solutions, and advantages of the present application clearer, the following will further describe in detail the embodiments of the present application in conjunction with the accompanying drawings.

[0030] When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended embodiments.

[0031] In the description of the present application, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances. In addition, in the description of the present application, unless otherwise specified, "a plurality" means two or more. " / ", describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art belonging to the technical field of the present application. The terms used in the description of this specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term " / and" used herein includes any and all combinations of one or more of the related listed items.

[0033] The inverter circuit can convert a DC voltage (e.g., battery voltage, accumulator voltage) into a high voltage and then invert it into an AC voltage (e.g., a sine wave of 220V, 50Hz) to meet the requirements of different devices or circuits, thus being widely used in various fields. Currently, the inverter circuit is provided with an isolation boost circuit, such as a push-pull circuit, a full-bridge circuit, and a half-bridge circuit, etc. Among them, the push-pull circuit belongs to a topology structure with transformer isolation. Exemplarily, the push-pull circuit usually consists of a transformer and two power tubes with the same parameters. The power tubes can use bipolar junction transistors (BJTs) or metal-oxide-semiconductor (MOS) transistors, and the driving of the two power tubes is out of phase. During operation, only one of the two power tubes conducts each time, with small conduction losses and high efficiency.

[0034] However, parasitic inductances usually exist in the push-pull circuit (such as the lead inductance of the circuit board trace and the parasitic inductance of the component PIN), the exciting inductance of the transformer winding, and the leakage inductance of the winding. During the turn-off process of the power transistor, the inductor current lags behind the change of the voltage, which will generate a large spike voltage on the power transistor and form a large surge current in the circuit. When the spike voltage is too high and exceeds the device specification of the power transistor, the power transistor will be damaged and unable to be used normally, thus affecting the normal use of the push-pull circuit.

[0035] Therefore, the embodiment of the present application provides an absorption circuit and an inverter. The absorption circuit can absorb and store the generated spike voltage to ensure the operation stability and reliability of the first switching transistor and the second switching transistor, and thus ensure the operation stability and reliability of the whole inverter. At the same time, the spike voltage can be fed back to the first capacitor to realize the energy recovery of the spike voltage, avoid the problem that the spike voltage is consumed by other components, improve the power supply efficiency of the first capacitor, and thus ensure the conversion efficiency of the whole inverter.

[0036] The absorption circuit and the inverter provided by the present application are introduced exemplarily below with reference to the drawings.

[0037] The embodiment of the present application provides an inverter, as Figure 1 shown, the inverter may include an isolation circuit 1. The isolation circuit 1 includes a first capacitor C1, a transformer T, a first switching transistor Q1, and a second switching transistor Q2. The first plate of the first capacitor C1 is connected to the input end of the transformer T. The controlled end of the first switching transistor Q1 is connected to a first control signal PWMA. The first end of the first switching transistor Q1 is connected to the first end of the transformer T. The controlled end of the second switching transistor Q2 is connected to a second control signal PWMB. The first end of the second switching transistor Q2 is connected to the first end of the transformer T. The second plate of the first capacitor C1, the second end of the first switching transistor Q1, and the second end of the second switching transistor Q2 are grounded. Among them, the first control signal PWMA and the second control signal PWMB are opposite signals, that is, when the first control signal PWMA is a high-level signal, the second control signal PWMB is a low-level signal, so that when the isolation circuit 1 works, the first switching transistor Q1 and the second switching transistor Q2 conduct and turn off alternately, and the first capacitor C1 is used to provide a power supply voltage for devices such as the transformer T.

[0038] To avoid the problem that the first switching transistor Q1 and the second switching transistor Q2 generate a large spike voltage during the turn-off process and cause damage to the first switching transistor Q1 and the second switching transistor Q2, as Figure 1As shown, the inverter further includes an absorption circuit 2, which is connected to the isolation circuit 1. The absorption circuit 2 can absorb the generated spike voltage when the first switching tube Q1 or the second switching tube Q2 is turned off, so as to ensure the operation reliability of the first switching tube Q1 and the second switching tube Q2, and further ensure the allowable reliability of the isolation circuit 1.

[0039] In one example, as Figure 2 shown, the absorption circuit 2 may include an absorption module 21, a switching module 22, and an adjustment module 23. The first end of the absorption module 21 is connected to the first end of the first switching tube Q1 and the first end of the transformer T. The second end of the absorption module 21 is connected to the first end of the second switching tube Q2 and the second end of the transformer T. The third end of the absorption module 21 is connected to the input end of the transformer T. The first end of the switching module 22 is connected to the fourth end of the absorption module 21. The second end of the switching module 22 is connected to the first plate of the first capacitor C1 and the input end of the transformer T. The first end of the adjustment module 23 is connected to the first end of the switching module 22. The second end of the adjustment module 23 is connected to the controlled end of the switching module 22. The third end of the adjustment module 23 is connected to the controlled end of the first switching tube Q1 and the controlled end of the second switching tube Q2.

[0040] In this example, when the isolation circuit 1 is in the working state, the absorption module 21 can absorb the spike voltage on the first switching tube Q1 or the second switching tube Q2. Exemplarily, when the first switching tube Q1 is turned off and the second switching tube Q2 is turned on, the absorption module 21 can absorb and store the spike voltage generated when the first switching tube Q1 is turned off; when the first switching tube Q1 is turned on and the second switching tube Q2 is turned off, the absorption module 21 can absorb and store the spike voltage generated when the second switching tube Q2 is turned off. Thus, when either the first switching tube Q1 or the second switching tube Q2 is turned off, the absorption module 21 can absorb and store the corresponding generated spike voltage, so as to avoid the problem that the first switching tube Q1 or the second switching tube Q2 is damaged and cannot be used normally due to too high spike voltage, which in turn affects the normal use of the inverter, ensuring the operation stability and reliability of the first switching tube Q1 and the second switching tube Q2, and further ensuring the operation stability and reliability of the overall inverter.

[0041] Optionally, the isolation circuit 1 can be a push-pull boost circuit, or a flyback single-ended excitation topology circuit such as a flyback, or other circuit structures. In this regard, the present application does not make specific limitations.

[0042] When current passes through the coil of transformer T, an induced electromotive force will be generated at both ends. When the first switching transistor Q1 or the second switching transistor Q2 is turned off, the current disappears, and the induced electromotive force generated by the coil of transformer T will generate a reverse voltage on the first switching transistor Q1 or the second switching transistor Q2. When the reverse voltage is greater than the reverse breakdown voltage of the first switching transistor Q1 or the second switching transistor Q2, it will cause the first switching transistor Q1 or the second switching transistor Q2 to be damaged, affecting the normal use of the first switching transistor Q1 and the second switching transistor Q2. To avoid the problem that the first switching transistor Q1 or the second switching transistor Q2 is damaged due to excessive reverse voltage, in one example, as Figure 3 shown, the absorption module 21 may include a freewheeling unit 211 and a third capacitor C3. The first input terminal of the freewheeling unit 211 is connected to the first terminal of the first switching transistor Q1 and the first terminal of the transformer T. The second input terminal of the freewheeling unit 211 is connected to the first terminal of the second switching transistor Q2 and the second terminal of the transformer T. The first plate of the third capacitor C3 is connected to the output terminal of the freewheeling unit 211 and the first terminal of the switching module 22. The second plate of the third capacitor C3 is connected to the input terminal of the transformer T.

[0043] In this example, the spike voltage generated when the first switching transistor Q1 or the second switching transistor Q2 is turned off will charge the third capacitor C3 through the freewheeling unit 211, so that the absorption module 21 can absorb and store the spike voltage, thereby avoiding the problem that the first switching transistor Q1 or the second switching transistor Q2 is damaged and cannot be used normally due to excessive spike voltage, and further affecting the normal use of the inverter, ensuring the operation stability and reliability of the first switching transistor Q1 and the second switching transistor Q2, and further ensuring the operation stability and reliability of the entire inverter. At the same time, when the current flowing through the coil of the transformer T disappears due to the turn-off of the first switching transistor Q1 or the second switching transistor Q2, the induced electromotive force generated by the coil can do work through the freewheeling unit 211 and be consumed, so as to avoid the problem that the induced electromotive force generated by the coil of the transformer T generates a reverse voltage on the first switching transistor Q1 or the second switching transistor Q2, resulting in the damage of the first switching transistor Q1 or the second switching transistor Q2, further improving the operation stability and reliability of the first switching transistor Q1 and the second switching transistor Q2, and further improving the operation stability and reliability of the entire inverter. Moreover, the absorption module 21 has a better absorption effect on the spike voltage, and can make the isolation circuit 1 (such as a push-pull circuit) provided in this application equivalent to a half-bridge circuit, that is, the isolation circuit 1 can achieve the effect of zero spike voltage in the half-bridge circuit.

[0044] Optionally, as Figure 3As shown, the freewheeling unit 211 may include a second freewheeling diode D2 and a third freewheeling diode D3. The positive electrode of the second freewheeling diode D2 is connected to the first end of the first switching transistor Q1 and the first end of the transformer T. The negative electrode of the second freewheeling diode D2 is connected to the first plate of the third capacitor C3 and the first end of the switching module 22. The positive electrode of the third freewheeling diode D3 is connected to the first end of the second switching transistor Q2 and the second end of the transformer T. The negative electrode of the third freewheeling diode D3 is connected to the negative electrode of the second freewheeling diode D2, the first plate of the third capacitor C3, and the first end of the switching module 22.

[0045] In this way, when the first switching transistor Q1 is turned off and the current flowing through the first end of the transformer T coil disappears, the induced electromotive force generated by the coil can do work through the second freewheeling diode D2 and thus be consumed, so as to avoid the problem that the induced electromotive force generated at the first end of the transformer T coil generates a reverse voltage on the first switching transistor Q1 and causes the first switching transistor Q1 to be damaged; when the second switching transistor Q2 is turned off and the current flowing through the second end of the transformer T coil disappears, the induced electromotive force generated by the coil can do work through the third freewheeling diode D3 and thus be consumed, so as to avoid the problem that the induced electromotive force generated at the second end of the transformer T coil generates a reverse voltage on the second switching transistor Q2 and causes the second switching transistor Q2 to be damaged. In this way, the induced electromotive forces generated at the first end and the second end of the coil can be consumed respectively by the second freewheeling diode D2 and the third freewheeling diode D3, so as to improve the operation stability and reliability of the first switching transistor Q1 and the second switching transistor Q2, and further improve the operation stability and reliability of the entire inverter.

[0046] In order to avoid the problem that the peak voltage absorbed by the absorption module 21 is consumed by other components, resulting in a decrease in the overall conversion efficiency of the inverter, the absorption circuit 2 in this application is provided with a switching module 22 and an adjustment module 23. The adjustment module 23 is connected to the controlled ends of the first switching transistor Q1 and the second switching transistor Q2, that is, the adjustment module 23 can receive the first control signal PWMA and the second control signal PWMB in real time, and control the on-off of the switching module 22 based on the first control signal PWMA and the second control signal PWMB. When the switching module 22 is turned on, the peak voltage is fed back to the first capacitor C1 to realize the energy recovery of the peak voltage, avoid the problem that the peak voltage is consumed by other components, improve the power supply efficiency of the first capacitor C1, and thus ensure the overall conversion efficiency of the inverter.

[0047] In one example, as Figure 4As shown, the adjustment module 23 may include a second capacitor C2, a first resistor R1, and a second resistor R2. The first plate of the second capacitor C2 is connected to the controlled ends of the first switching transistor Q1 and the second switching transistor QC2 at a first node A. One end of the first resistor R1 is connected to the second plate of the second capacitor C2 at a second node B. The other end of the first resistor R1 is connected to the first end of the switching module 22. One end of the second resistor R2 is connected to the first node A. The other end of the second resistor R2 is connected to the controlled end of the switching module 22 at a third node C. The third node C is connected to the second node B.

[0048] In this example, the control of the switching module 22 can be achieved through the second capacitor C2, the first resistor R1, and the second resistor R2. Below, taking the switching module 22 as a P-type metal-oxide-semiconductor (P-MOS) transistor or an N-type metal-oxide-semiconductor (N-MOS) transistor as an example, an exemplary description of the switching module 22 and the adjustment module 23 of the present application will be given.

[0049] As Figure 5 shown, the switching module 22 may include a PMOS transistor PM. The source of the PMOS transistor PM is connected to the other end of the first resistor R1. The drain of the PMOS transistor PM is connected to the first plate of the first capacitor C1 and the input end of the transformer T. The gate of the PMOS transistor PM is connected to the third node C. In this example, when the first control signal PWMA is at a low level, it will pull down the second capacitor C2 and the second resistor R2 to reduce the gate-source voltage of the PMOS transistor PM, making the PMOS transistor PM conduct, so that the energy of the spike voltage stored in the third capacitor C3 can charge the first capacitor C1, that is, the energy of the spike voltage stored in the third capacitor C3 can flow back to the first capacitor C1, achieving the recovery of the energy of the spike voltage, avoiding the problem that the spike voltage is consumed by other components, improving the power supply efficiency of the first capacitor C1, and thus ensuring the overall conversion efficiency of the inverter. When the first control signal PWMA is at a high level, the first resistor R1 is pulled up to increase the gate-source voltage of the PMOS transistor PM, making the PMOS transistor PM turn off. In this example, the control process of the PMOS transistor PM by the adjustment module 23 based on the high and low levels of the second control signal PWMB is the same as that of the first control signal PWMA, and thus will not be elaborated here.

[0050] In this way, the adjustment module 23 can control the on / off of the PMOS transistor PM based on the first control signal PWMA and the second control signal PWMB, thereby realizing the energy recovery of the spike voltage, avoiding the problem that the spike voltage is consumed by other components, improving the power supply efficiency of the first capacitor C1, and thus ensuring the overall conversion efficiency of the inverter.

[0051] As Figure 6 shown, the switching module 22 may include an NMOS transistor NM. The drain of the NMOS transistor NM is connected to the other end of the first resistor R1. The source of the NMOS transistor NM is connected to the first plate of the first capacitor C1 and the input terminal of the transformer T. The gate of the NMOS transistor NM is connected to the third node C. In this example, when the first control signal PWMA is at a high level, the second capacitor C2 and the second resistor R2 are lifted to increase the gate-drain voltage of the NMOS transistor NM, so that the NMOS transistor NM is turned on, enabling the energy of the spike voltage stored in the third capacitor C3 to charge the first capacitor C1, that is, the energy of the spike voltage stored in the third capacitor C3 can flow back to the first capacitor C1, realizing the energy recovery of the spike voltage, avoiding the problem that the spike voltage is consumed by other components, improving the power supply efficiency of the first capacitor C1, and thus ensuring the overall conversion efficiency of the inverter. When the first control signal PWMA is at a low level, the first resistor R1 is pulled low to reduce the gate-drain voltage of the NMOS transistor NM, so that the NMOS transistor NM is turned off. In this example, the control process of the adjustment module 23 for the NMOS transistor NM based on the high and low levels of the second control signal PWMB is the same as that of the first control signal PWMA, and thus will not be elaborated here.

[0052] In this way, the adjustment module 23 can control the on / off of the NMOS transistor NM based on the first control signal PWMA and the second control signal PWMB, thereby realizing the energy recovery of the spike voltage, avoiding the problem that the spike voltage is consumed by other components, improving the power supply efficiency of the first capacitor C1, and thus ensuring the overall conversion efficiency of the inverter. The adjustment module 23 may also adopt other devices or circuits that can achieve the above functions, and this application does not make specific limitations in this regard.

[0053] In summary, when any one of the first switching transistor Q1 or the second switching transistor Q2 in the absorption circuit 2 provided in this application is turned off, the absorption module 21 can absorb and store the corresponding generated spike voltage, so as to avoid the problem that the first switching transistor Q1 or the second switching transistor Q2 is damaged and cannot be used normally due to the excessive spike voltage, which in turn affects the normal use of the inverter, ensuring the operating stability and reliability of the first switching transistor Q1 and the second switching transistor Q2, and thus ensuring the overall operating stability and reliability of the inverter. At the same time, the adjustment module 23 can control the on / off of the switching module 22 according to the first control signal PWMA or the second control signal PWMB, so that when the switching module 22 is turned on, the spike voltage is fed back to the first capacitor C1 to realize the energy recovery of the spike voltage, avoiding the problem that the spike voltage is consumed by other components, improving the power supply efficiency of the first capacitor C1, and thus ensuring the overall conversion efficiency of the inverter.

[0054] In one example, as Figure 7 shown, the absorption circuit 2 may further include an inductor L and a first freewheeling diode D1. One end of the inductor L is connected to the second end of the switching module 22, the other end of the inductor L is connected to the first plate of the first capacitor C1 and the input terminal of the transformer T, the positive electrode of the first freewheeling diode D1 is connected to the first plate of the first capacitor C1 and the input terminal of the transformer T, and the negative electrode of the first freewheeling diode is connected to one end of the inductor and the second end of the switching module 22. In this example, when the switching module 22 is turned on, the energy of the spike voltage stored in the third capacitor C3 will charge the first capacitor C1 through the switching module 22 and the inductor L to realize the energy recovery of the spike voltage; when the switching module 22 is turned off, the current of the inductor L will freewheel through the first freewheeling diode D1.

[0055] Since the isolation circuit 1 (such as a push-pull circuit) generates a certain amount of ripple current and voltage during operation, in one example, as Figure 7 shown, the absorption circuit 2 may further include a filtering module 24. One end of the filtering module 24 is connected to the other end of the inductor L and the first plate of the first capacitor C1, and the other end of the filtering module 24 is connected to the positive electrode of the first freewheeling diode D1 and the input terminal of the transformer T. The filtering module 24 can filter the voltage output by the first capacitor C1 to reduce the voltage ripple output by the first capacitor C1, thereby ensuring the stability of the voltage output by the first capacitor C1.

[0056] Optionally, the filtering module 24 may include one or more filtering capacitors connected in series. The specific number of filtering capacitors may be set according to actual requirements. For example, assuming that it is desired to reduce the manufacturing cost and the size of the isolation circuit 1, the filtering module 24 may include only one filtering capacitor; assuming that it is desired to further enhance the stability and reliability of the voltage output by the first capacitor C1, the filtering module 24 may include multiple filtering capacitors connected in series. That is, when one of the multiple filtering capacitors fails, the other filtering capacitors can still continue to provide the filtering function to improve the stability and reliability of the voltage output by the first capacitor C1, and thus improve the stability and reliability of the isolation circuit 1.

[0057] To improve the accuracy of the first control signal PWMA and the second control signal PWMB received by the adjustment module 23, in one example, as Figure 7 shown, the absorption circuit 2 may further include a driving module 25. The first end of the driving module 25 is connected to the third end of the adjustment module 23, the second end of the driving module 25 is connected to the controlled end of the first switching transistor Q1, and the third end of the driving module 25 is connected to the controlled end of the second switching transistor Q2. By means of the driving module 25, the accuracy of the first control signal PWMA and the second control signal PWMB received by the adjustment module 23 can be improved to ensure the adjustment reliability of the adjustment module 23.

[0058] Optionally, as Figure 7 shown, the driving module 25 may include a first driving diode D4 and a second driving diode D5. The positive electrode of the first driving diode D4 is connected to the third end of the adjustment module 22 (i.e., the first node A as Figure 7 shown), the negative electrode of the first driving diode D4 is connected to the controlled end of the first switching transistor Q1, the positive electrode of the second driving diode D5 is connected to the third end of the adjustment module 22 and the positive electrode of the first driving diode D4 at the fourth node D, and the negative electrode of the second driving diode D5 is connected to the controlled end of the second switching transistor Q2. The driving module 25 may also be provided with only one driving diode, which is respectively connected to the controlled ends of the first switching transistor Q1 and the second switching transistor Q2, or other devices or circuits capable of implementing the above functions may be used. In this regard, the present application does not make specific limitations.

[0059] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0060] The above embodiments only represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patented application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. An absorption circuit is applied to an isolation circuit. The isolation circuit includes a first capacitor, a transformer, a first switching transistor, and a second switching transistor. A first plate of the first capacitor is connected to an input end of the transformer. A controlled end of the first switching transistor receives a first control signal, and a controlled end of the second switching transistor receives a second control signal. It is characterized in that, The absorption circuit includes: An absorption module, the first end of the absorption module is connected to the first end of the first switching tube and the first end of the transformer, the second end of the absorption module is connected to the first end of the second switching tube and the second end of the transformer, and the third end of the absorption module is connected to the input end of the transformer; A switching module, the first end of the switching module is connected to the fourth end of the absorption module, and the second end of the switching module is connected to the first plate of the first capacitor and the input end of the transformer; and, An adjustment module, the first end of the adjustment module is connected to the first end of the switching module, the second end of the adjustment module is connected to the controlled end of the switching module, and the third end of the adjustment module is connected to the controlled ends of the first switching tube and the second switching tube. The adjustment module is configured to control the on / off of the switching module according to the first control signal or the second control signal.

2. The absorption circuit according to claim 1, wherein The adjustment module includes: A second capacitor, the first plate of the second capacitor is connected to the controlled ends of the first switching tube and the second switching tube at a first node; A first resistor, one end of the first resistor is connected to the second plate of the second capacitor at a second node, and the other end of the first resistor is connected to the first end of the switching module; and, A second resistor, one end of the second resistor is connected to the first node, and the other end of the second resistor is connected to the controlled end of the switching module at a third node, and the third node is connected to the second node.

3. The absorption circuit according to claim 2, wherein The switching module includes: A P-type metal-oxide-semiconductor transistor, the source of the P-type metal-oxide-semiconductor transistor is connected to the other end of the first resistor, the drain of the P-type metal-oxide-semiconductor transistor is connected to the first plate of the first capacitor and the input end of the transformer, and the gate of the P-type metal-oxide-semiconductor transistor is connected to the third node; Or, An N-type metal-oxide-semiconductor transistor, the drain of the N-type metal-oxide-semiconductor transistor is connected to the other end of the first resistor, the source of the N-type metal-oxide-semiconductor transistor is connected to the first plate of the first capacitor and the input end of the transformer, and the gate of the N-type metal-oxide-semiconductor transistor is connected to the third node.

4. The absorption circuit according to claim 1, characterized in that, The absorption circuit further includes: An inductor, one end of the inductor is connected to the second end of the switching module, and the other end of the inductor is connected to the first plate of the first capacitor and the input end of the transformer; and, A first freewheeling diode, the anode of the first freewheeling diode is connected to the first plate of the first capacitor and the input end of the transformer, and the cathode of the first freewheeling diode is connected to one end of the inductor and the second end of the switching module.

5. The absorption circuit according to claim 4, wherein The absorption circuit further includes: A filtering module, one end of the filtering module is connected to the other end of the inductor and the first plate of the first capacitor, and the other end of the filtering module is connected to the anode of the first freewheeling diode and the input end of the transformer.

6. The absorption circuit according to any one of claims 1-5, characterized in that, The absorption module includes: A freewheeling unit, the first input terminal of the freewheeling unit is connected to the first end of the first switching tube and the first end of the transformer, and the second input terminal of the freewheeling unit is connected to the first end of the second switching tube and the second end of the transformer; and, A third capacitor, the first plate of the third capacitor is connected to the output terminal of the freewheeling unit and the first end of the switching module, and the second plate of the third capacitor is connected to the input terminal of the transformer.

7. The absorption circuit according to claim 6, wherein The freewheeling unit includes: A second freewheeling diode, the anode of the second freewheeling diode is connected to the first end of the first switching tube and the first end of the transformer, and the cathode of the second freewheeling diode is connected to the first plate of the third capacitor and the first end of the switching module; and, A third freewheeling diode, the anode of the third freewheeling diode is connected to the first end of the second switching tube and the second end of the transformer, and the cathode of the third freewheeling diode is connected to the cathode of the second freewheeling diode, the first plate of the third capacitor and the first end of the switching module.

8. The absorption circuit according to claim 6, wherein The absorption circuit further includes: A driving module, the first end of the driving module is connected to the third end of the regulating module, the second end of the driving module is connected to the controlled end of the first switching tube, and the third end of the driving module is connected to the controlled end of the second switching tube.

9. The absorption circuit according to claim 8, characterized in that, The driving module includes: A first driving diode, the anode of the first driving diode is connected to the third end of the regulating module, and the cathode of the first driving diode is connected to the controlled end of the first switching tube; and, A second driving diode, the anode of the second driving diode is connected to the third end of the regulating module and the anode of the first driving diode at a fourth node, and the cathode of the second driving diode is connected to the controlled end of the second switching tube.

10. An inverter, characterized in that, Includes: The absorption circuit according to any one of claims 1-9; And, An isolation circuit, including a first capacitor, a transformer, a first switching tube and a second switching tube, the first plate of the first capacitor is connected to the input terminal of the transformer, the controlled end of the first switching tube receives a first control signal, the first end of the first switching tube is connected to the first end of the transformer, the controlled end of the second switching tube receives a second control signal, the first end of the second switching tube is connected to the first end of the transformer, and the second plate of the first capacitor, the second end of the first switching tube and the second end of the second switching tube are grounded.

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