Peak voltage absorption circuit and inverter

Abstract

The utility model provides a peak voltage absorption circuit and an inverter. The peak voltage absorption circuit comprises a rectifier bridge, a voltage-sensitive unit, an energy storage unit and an absorption unit, the peak voltage absorption circuit is connected between a first node and a second node, two alternating current input ends of a rectifier bridge are respectively connected with the first node and the second node, and a voltage-sensitive unit, an energy storage unit and an absorption unit are connected in parallel between two direct current output ends of the rectifier bridge; aiming at the amplitude of the peak voltage generated in the circuit, different electronic devices are dynamically used for discharging the peak voltage in combination with the voltage-sensitive voltage of the voltage-sensitive unit, so that complete consumption of the peak voltage is realized. According to the peak voltage absorption circuit, the overall efficiency of an inverter is improved, the probability of damage of a switching device in an alternating current conversion circuit is reduced, the reliability of the inverter is improved, the loss of a power device is reduced, the safety risk caused by peak voltage is reduced, and the maintenance cost is reduced.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a peak voltage absorption circuit and an inverter. Background Technology

[0002] In commonly used isolated inverters, the primary and secondary sides are isolated by a transformer. The secondary side typically has an H-bridge to convert high-frequency AC power into AC power of the required voltage and frequency. The H-bridge usually consists of four switching devices, such as MOSFETs or IGBTs, and the output of the isolated inverter is adjusted by controlling their switching.

[0003] In the actual use of isolated inverters, when the switching devices of the H-bridge are suddenly turned off, the rate of change of current increases sharply, and the parasitic inductance in the circuit (such as line inductance, transformer leakage inductance, etc.) will generate induced voltage, resulting in voltage spikes, thus generating peak voltage.

[0004] Existing technologies typically add bus capacitors on the secondary side to absorb voltage spikes. However, if the spike energy is too large (such as high energy storage in transformer leakage inductance), the bus capacitors cannot completely absorb it, which can easily lead to damage to electronic components. Utility Model Content

[0005] This application provides a peak voltage absorption circuit and an inverter to solve the technical problem that excessive peak energy (such as high leakage inductance energy stored in transformers) cannot be completely absorbed by the bus capacitor, which can easily lead to damage to electronic components.

[0006] On the one hand, this application provides a spike voltage absorption circuit, which is connected between a first node and a second node. The spike voltage absorption circuit includes: a rectifier bridge, a varistor unit, an energy storage unit, and an absorption unit.

[0007] The two AC input terminals of the rectifier bridge are connected to the first node and the second node respectively, and the varistor unit, the energy storage unit and the absorption unit are connected in parallel between the two DC output terminals of the rectifier bridge.

[0008] In the aforementioned spike voltage absorption circuit, optionally, the varistor unit includes one or more varistors connected in parallel, wherein the one or more varistors are connected between the two DC output terminals of the rectifier bridge.

[0009] In the aforementioned peak voltage absorption circuit, optionally, the energy storage unit includes one or more first capacitors connected between the two DC output terminals of the rectifier bridge.

[0010] In the above-described peak voltage absorption circuit, optionally, the absorption unit includes one or more resistors connected in series, the one or more resistors connected in series being connected between the two DC output terminals of the rectifier bridge.

[0011] In the aforementioned spike voltage absorption circuit, optionally, the rectifier bridge includes a first diode, a second diode, a third diode, and a fourth diode;

[0012] The anode of the first diode and the cathode of the second diode are both connected to the first node;

[0013] The anode of the third diode and the cathode of the second diode are both connected to the second node;

[0014] The cathodes of the first diode and the third diode are both connected to the first DC output terminal of the two DC output terminals of the rectifier bridge.

[0015] The anodes of the second diode and the fourth diode are both connected to the second DC output terminal of the two DC output terminals of the rectifier bridge.

[0016] In the above-mentioned peak voltage absorption circuit, optionally, the resistance value of the absorption unit is greater than the resistance value of the varistor unit in the on state.

[0017] In the above-mentioned peak voltage absorption circuit, optionally, the resistance value of the absorption unit is less than the resistance value of the varistor unit in the off state.

[0018] On the other hand, this application provides an inverter, including: an AC conversion circuit and a spike voltage absorption circuit as described in the first aspect and various possible implementations of the first aspect above;

[0019] The two AC input terminals of the AC conversion circuit are the first node and the second node, respectively.

[0020] Optionally, in the aforementioned spike voltage absorption circuit, the inverter may also include an isolation transformer;

[0021] The secondary side of the isolation transformer is connected to the two AC input terminals of the AC conversion circuit.

[0022] Optionally, in the above-mentioned peak voltage absorption circuit, the inverter may also include: at least one DC-AC conversion circuit;

[0023] The AC output terminal of the DC-AC conversion circuit is connected to the primary side of the isolation transformer, and the DC input terminal of the DC-AC conversion circuit is connected to the DC power supply.

[0024] The spike voltage absorption circuit provided in this application includes an absorption unit, an energy storage unit, a varistor unit, and a rectifier bridge. The spike voltage absorption circuit is connected between a first node and a second node. The two AC input terminals of the rectifier bridge are respectively connected to the first node and the second node. The varistor unit, energy storage unit, and absorption unit are connected in parallel between the two DC output terminals of the rectifier bridge. Based on the amplitude of the spike voltage generated in the circuit, and combined with the varistor unit's varistor voltage, different electronic devices are dynamically used to discharge the spike voltage, thereby achieving complete consumption of the spike voltage, improving the overall efficiency of the inverter, reducing the probability of damage to switching devices in the AC conversion circuit, improving the reliability of the inverter, reducing power device losses, reducing the safety risks caused by spike voltage, and reducing maintenance costs. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0026] Figure 1 This application provides a partial structural schematic diagram of an inverter.

[0027] Figure 2 A schematic diagram of a spike voltage absorption circuit provided in this application Figure 1 ;

[0028] Figure 3 A schematic diagram of a spike voltage absorption circuit provided in this application Figure 2 .

[0029] Explanation of reference numerals in the attached figures:

[0030] 101 - DC power supply;

[0031] 102 - DC-AC switching circuit;

[0032] 103 - Isolation Transformer;

[0033] 104 - AC conversion circuit;

[0034] 105-Peak voltage absorption circuit;

[0035] A - First node;

[0036] B - Second node;

[0037] C - First DC output terminal;

[0038] D - Second DC output terminal;

[0039] 501 - Absorption Unit;

[0040] 502 - Energy Storage Unit;

[0041] 503 - Pressure-sensitive unit;

[0042] 504 - Rectifier Bridge.

[0043] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0044] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0046] In the description of the embodiments of this application, it should be understood that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal connection of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0047] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented, for example, in orders other than those illustrated or described herein.

[0048] In this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0049] First, the terms used in this application will be explained:

[0050] Alternating current (AC) is electricity in which the direction of current and the magnitude of voltage change periodically over time. A typical waveform is a sine wave (such as in household power supplies).

[0051] Direct current (DC) is electricity with a fixed direction of current, and the voltage can be constant (such as in a battery) or fluctuate (such as rectified DC).

[0052] H-bridge: An electronic circuit topology consisting of four switches (such as transistors or MOSFETs) arranged in an "H" shape, used to control the direction and speed of a DC motor. It is widely used in DC-AC conversion, motor drive, power control and other fields. By controlling the conduction and cutoff of the four switches, the direction of current can be flexibly switched.

[0053] An Insulated Gate Bipolar Transistor (IGBT) is a composite, fully controllable power semiconductor device widely used in high-voltage, high-current switching control applications to control current flow and achieve DC-to-AC conversion, such as in frequency converters, electric vehicles, and industrial motor drives.

[0054] Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) is a semiconductor device that uses an electric field effect to control current. It features high input impedance, low drive power, and fast switching characteristics, and is widely used in analog circuits, digital circuits (such as CPUs and memory), and power electronics (such as switching power supplies and motor drives).

[0055] Varistors are resistors with nonlinear current-voltage characteristics. They are mainly used to clamp voltage when a circuit is subjected to overvoltage and absorb excess current to protect sensitive devices.

[0056] Varistor voltage: This is the core parameter of a varistor, referring to the voltage value it presents under a specified current, used to characterize its conduction threshold and clamping capability.

[0057] Joule heating effect: also known as resistance heating or ohmic heating, refers to the phenomenon that when an electric current passes through a conductor, electrical energy is converted into heat energy due to the presence of resistance.

[0058] An isolation inverter is a power electronic device that converts DC to AC. Its core feature is the physical separation between the input and output circuits through electrical isolation technology. This isolation design not only improves equipment safety but also enhances system stability and reliability, and it is widely used in new energy power generation, industrial control, medical equipment, and home appliances.

[0059] In commonly used isolated inverters, the primary and secondary sides are isolated by a transformer. The secondary side typically has an H-bridge to convert high-frequency AC power into AC power of the required voltage and frequency. The H-bridge usually consists of four switching devices, such as MOSFETs or IGBTs, and the output of the isolated inverter is adjusted by controlling their switching.

[0060] In the actual use of isolated inverters, when the switching devices of the H-bridge are suddenly turned off, the rate of change of current increases sharply, and the parasitic inductance in the circuit (such as line inductance, transformer leakage inductance, etc.) will generate induced voltage, resulting in voltage spikes, thus generating peak voltage.

[0061] Existing technologies typically add bus capacitors on the secondary side to absorb voltage spikes. However, if the spike energy is too large (such as high energy storage in transformer leakage inductance), the bus capacitors cannot completely absorb it, which can easily lead to damage to electronic components.

[0062] To address the aforementioned problems, this application provides a spike voltage absorption circuit. This spike voltage absorption circuit expands the communication circuit between electronic components and the device, thereby increasing the line current of the communication circuit, thus avoiding device malfunctions, solving the problem of cross-current before the peripheral circuit is expanded, and improving the user experience.

[0063] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0064] Figure 1 This application provides a partial structural schematic diagram of an inverter. Figure 2 A schematic diagram of a spike voltage absorption circuit provided in this application Figure 1 ; Figure 3 A schematic diagram of a spike voltage absorption circuit provided in this application Figure 2 .

[0065] See attached document Figure 1 As shown, in a first aspect, embodiments of this application provide an inverter, which includes: an AC conversion circuit 104 and a spike voltage absorption circuit 105.

[0066] Among them, the AC conversion circuit 104 is used to control the output direction of AC power and generate a complete AC waveform; the spike voltage absorption circuit 105 is used to absorb the spike voltage generated by the inverter.

[0067] The two AC input terminals of the AC conversion circuit 104 are the first node A and the second node B, respectively. The spike voltage absorption circuit 105 is connected to the AC conversion circuit 104 through the first node A and the second node B.

[0068] For example, the AC conversion circuit 104 can be an H-bridge, which is used to convert high-frequency AC power into AC power with the required voltage and frequency. An H-bridge typically consists of four switching devices, such as MOSFETs or IGBTs, whose switching is controlled to adjust the AC output. This application does not impose any special limitation on the specific number of switching devices constituting the AC conversion circuit 104.

[0069] Continue to refer to Figure 1 The inverter also includes: isolation transformer 103.

[0070] In this embodiment, the secondary side of the isolation transformer 103 is connected to the two AC input terminals of the AC conversion circuit 104, and the spike voltage absorption circuit 105 is connected in parallel with the secondary side of the isolation transformer 103.

[0071] The isolation transformer 103 is a transformer that electrically isolates the input and output circuits through the principle of electromagnetic induction. Electrical isolation blocks the DC component or common-mode interference between the input and output circuits, preventing electric shock or equipment damage. Voltage transformation adjusts the voltage level (e.g., step-up or step-down) through the turns ratio. In the isolation transformer 103, the primary and secondary sides correspond to the circuit sections containing the primary and secondary windings, respectively. The primary winding is connected to the input voltage, generating an alternating magnetic field. The secondary winding generates an output voltage through electromagnetic induction, achieving energy transfer.

[0072] The isolation transformer 103 installed in the inverter, through the synergistic effect of electrical isolation and voltage variation, not only ensures the safety of personnel and equipment during the operation of the inverter, but also significantly improves the output waveform quality and system stability through harmonic suppression and load buffering mechanisms. It is a key component for the inverter to achieve efficient and reliable operation.

[0073] Continue to refer to Figure 1The inverter also includes at least one DC-AC conversion circuit 102, with the AC output terminal of the DC-AC conversion circuit 102 connected to the primary side of the isolation transformer 103, and the DC input terminal of the DC-AC conversion circuit 102 connected to the DC power supply 101.

[0074] Understandably, the DC power supply 101 can provide a stable DC input to the inverter. The DC power supply 101 can be, for example, a battery, a solar panel, a DC grid, or other DC power supply equipment. The DC-AC conversion circuit 102 is the core conversion unit of the inverter. It can convert the DC power provided by the DC power supply 101 into AC power, realizing the DC-to-AC conversion. The DC-AC conversion circuit 102 can be, for example, composed of switching devices (e.g., IGBTs or MOSFETs), filter circuits (e.g., capacitors), freewheeling diodes, and control circuits.

[0075] As an optional implementation, the inverter further includes an output unit (not shown in the figure), which is connected to the AC conversion circuit 104.

[0076] In this embodiment, the core function of the inverter is to convert direct current (DC) to alternating current (AC), enabling the DC power supply 101 to drive devices requiring AC power. Specifically, the DC power supply 101 is connected to the DC input terminal of the DC-AC conversion circuit 102 via wires. The DC output terminal of the DC-AC conversion circuit 102 is connected to the primary side of the isolation transformer 103. The secondary side of the isolation transformer 103 is connected to the two AC input terminals of the AC conversion circuit 104. A spike voltage absorption circuit 105 is also connected to the two AC input terminals of the AC conversion circuit 104. The AC output terminal of the AC conversion circuit 104 is connected to an output unit. The output unit can be, for example, an industrial motor. This application does not impose any special limitations on the output unit.

[0077] For example, DC power supply 101 provides the DC power required for conversion to the inverter. The DC power is transmitted to DC-AC conversion circuit 102 through wires connected to DC-AC conversion circuit 102, where DC-AC conversion circuit converts the input DC power into AC power and inputs it to the primary side of isolation transformer 103. Isolation transformer 103 performs voltage transformation and electrical isolation on the converted AC power, and inputs it to AC conversion circuit 104 through the secondary side of isolation transformer 103. According to actual needs, the AC power is converted in terms of voltage and frequency, and the converted AC power is transmitted to the output unit to meet the user's actual power needs. When the inverter is working normally, the current in the circuit does not flow through the spike voltage absorption circuit 105, or the current flowing through the spike voltage absorption circuit 105 is extremely small and can be ignored. When all the switches of the AC conversion circuit 104 are quickly turned off, the secondary winding, that is, the secondary side of the isolation transformer 103, generates a spike voltage. At this time, the spike voltage generated is absorbed and consumed by the spike voltage absorption circuit 105 connected in parallel with the secondary side of the isolation transformer 103.

[0078] The inverter provided in this application includes: a DC power supply 101, at least one DC-AC conversion circuit 102, an isolation transformer 103, an AC conversion circuit 104, and a spike voltage absorption circuit 105; the two AC input terminals of the AC conversion circuit 104 are a first node A and a second node B, respectively; the secondary side of the isolation transformer 103 is connected to the two AC input terminals of the AC conversion circuit 104; the AC output terminal of the DC-AC conversion circuit 102 is connected to the primary side of the isolation transformer 103, and the DC input terminal of the DC-AC conversion circuit 102 is connected to the DC power supply 101; by utilizing the spike voltage absorption circuit 105, the inverter can completely absorb spike voltages, improve the overall operating efficiency of the inverter, reduce the probability of damage to the switching devices in the AC conversion circuit 104, and thus reduce maintenance costs.

[0079] See appendix Figure 2 Secondly, embodiments of this application provide a spike voltage absorption circuit 105, which is connected between a first node A and a second node B. The spike voltage absorption circuit 105 includes an absorption unit 501, an energy storage unit 502, a varistor unit 503, and a rectifier bridge 504.

[0080] The two AC input terminals of the rectifier bridge 504 are connected to the first node A and the second node B respectively, and the varistor unit 503, the energy storage unit 502 and the absorption unit 501 are connected in parallel between the two DC output terminals (the first DC output terminal C and the second DC output terminal D) of the rectifier bridge 504.

[0081] Understandably, the core function of a rectifier bridge is to convert input AC power into DC power, and the unidirectional conductivity of the rectifier bridge can prevent the negative half-cycle of the AC power from directly damaging subsequent circuits.

[0082] When all switching devices in the AC conversion circuit 104 are turned off rapidly, a voltage spike will be generated in the secondary winding of the isolation transformer 103, mainly caused by sudden current changes and parasitic inductance. The voltage spike may damage the switching devices, secondary winding and load, and cause problems such as electromagnetic interference and reduced system efficiency. The voltage spike absorption circuit 105 can effectively absorb the voltage spike generated at this time, thereby improving the reliability and stability of the inverter.

[0083] The spike voltage absorption circuit 104 provided in this application embodiment uses a rectifier bridge 504 to convert the AC power in the isolation transformer 103 into DC power, so that the spike voltage can be stably transmitted to the absorption unit 501, energy storage unit 502 and varistor unit 503 for consumption or absorption; through the absorption unit 501, energy storage unit 502 and varistor unit 503, the consumption or absorption of spike voltages of different amplitudes can be realized, thereby protecting the electronic components in the AC conversion circuit 104 and reducing the maintenance cost of the inverter.

[0084] See attached document Figure 3 As an optional implementation, the rectifier bridge 504 includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4; the anode of the first diode D1 and the cathode of the second diode D2 are both connected to a first node; the anode of the third diode D3 and the cathode of the fourth diode D4 are both connected to a second node; the cathodes of the first diode D1 and the third diode D3 are both connected to the first DC output terminal C of the two DC output terminals of the rectifier bridge 504; the anodes of the second diode D2 and the fourth diode D4 are both connected to the second DC output terminal D of the two DC output terminals of the rectifier bridge 504.

[0085] For example, by alternately conducting the first diode D1, the second diode D2, the third diode D3, and the fourth diode D4, a continuous pulsating DC current is output using the positive and negative half-cycles of the AC current, providing stable energy support for subsequent circuits. Specifically, when the AC input voltage is in the positive half-cycle, the first AC input terminal, i.e., the first node A, is positive, and the second AC input terminal, i.e., the second node B, is negative. Based on the unidirectional conductivity characteristic of diodes, the first diode D1 and the fourth diode D4 conduct at this time, and the current flows from the first node A through the first diode D1 to the first DC output terminal C, then through the load to the second DC output terminal D, and then through the fourth diode D4 back to the second node B. When the AC input voltage is in the negative half-cycle, the first node A is negative, and the second node B is positive. Also based on the unidirectional conductivity principle, the second diode D2 and the third diode D3 conduct at this time, and the current flows from the second node B through the third diode D3 to the first DC output terminal C, then through the load to the second DC output terminal D, and then through the second diode D2 back to the first node A.

[0086] It is understandable that when all switches in the AC conversion circuit 104 are turned off, the peak voltage generated under different conditions will vary due to the combined effects of factors such as energy source intensity, circuit parameter differences, load characteristics, and environmental interference.

[0087] For example, energy source intensity includes: external impact energy (e.g., inverter struck by lightning or grid failure) and internal energy release (e.g., inductor energy storage or capacitor discharge); circuit parameter differences include: parasitic parameter effects (e.g., distributed inductance or parasitic capacitance) and damping effects (e.g., line resistance or load impedance); load characteristics include: inductive load switching (e.g., sudden changes in inductor current or the presence of a freewheeling loop) and capacitive loads (e.g., resonant overvoltage); environmental interference includes: electromagnetic interference and environmental factors.

[0088] Continue to refer to the appendix Figure 3 As an optional implementation, the varistor unit 503 includes one or more varistors connected in parallel, and the one or more varistors connected in parallel are connected between the two DC output terminals of the rectifier bridge 504.

[0089] Understandably, based on the nonlinear volt-ampere characteristics of varistors, when the varistor is under normal voltage, it exhibits a high resistance state (e.g., megaohms) and minimal leakage current (microamps), allowing the circuit to operate normally. Overvoltage triggering occurs when the voltage exceeds the varistor voltage, causing the resistance to drop sharply (to the ohm level), forming a low-resistance path and absorbing surge energy. At this time, the varistor dissipates the surge energy through its own heating, preventing the overvoltage from being transmitted to subsequent circuits. When the overvoltage disappears, the varistor returns to its high resistance state, and the circuit returns to a safe state.

[0090] See attached document Figure 3 As an optional implementation, the energy storage unit 502 includes a first capacitor C1, which is connected between the two DC output terminals of the rectifier bridge 504.

[0091] Understandably, the first capacitor C1 is used to absorb voltage spikes; when a voltage spike occurs, the first capacitor C1 charges quickly, absorbs excess energy, and suppresses the voltage rise.

[0092] In this embodiment, the energy storage unit 502 can contain one or more capacitors, that is, the number of first capacitors C1 can be one or more. Specifically, when there are multiple capacitors, connecting them in series can increase the total withstand voltage of the energy storage unit 502, but the capacity of the energy storage unit 502 decreases, and the energy that can be absorbed decreases. If the capacity meets the current usage requirements, multiple capacitors can be connected in series to increase the withstand voltage. Connecting multiple capacitors in parallel can increase the capacity of the energy storage unit 502 without changing the withstand voltage. Therefore, when there are multiple capacitors in the energy storage unit 502, these multiple capacitors can be a combination of series and parallel connections. This application does not impose any special restrictions on the connection method of the multiple capacitors.

[0093] See attached document Figure 3 As an optional implementation, the absorption unit 501 includes one or more resistors connected in series, which are connected between the two DC output terminals of the rectifier bridge 504.

[0094] In this embodiment, the resistor in the absorption unit 501 is used to dissipate the voltage spike. When the voltage spike occurs, the resistor in the absorption unit 501 converts electrical energy into heat energy through the Joule heating effect, thereby dissipating the voltage spike.

[0095] As an optional implementation, the resistance of the absorption unit 501 is greater than the resistance of the varistor unit 503 in the on state.

[0096] As an optional implementation, the resistance of the absorption unit 501 is less than the resistance of the varistor unit 503 in the off state.

[0097] Understandably, when the peak voltage is lower than the varistor voltage in the varistor unit 503, the varistor exhibits high impedance, and the varistor unit 503 is in the off state; when the peak voltage is higher than the varistor voltage in the varistor unit 503, the varistor quickly enters a low resistance state, and the varistor unit 503 is in the on state.

[0098] For example, continue to refer to the appendix. Figure 3The absorption unit 501 consists of four resistors connected in series, specifically: a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4; the energy storage unit 502 consists of a first capacitor C1; the varistor unit 503 consists of a first varistor R5 and a second varistor R6; and the rectifier bridge 504 consists of a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. When all the switching devices in the H-bridge are turned off, if the peak voltage generated is lower than the varistor voltage of the varistor in the varistor unit 503, it indicates that the first varistor R5 and the second varistor R6 are in the off state, and the current peak voltage is small, so the varistor unit 503 does not need to discharge the voltage. At this time, the peak voltage is discharged by the first resistor R1. The voltage spike generated is consumed by the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4, and absorbed by the first capacitor C1. If the voltage spike generated is higher than the voltage of the varistor in the varistor unit 503, it indicates that the first varistor R5 and the second varistor R6 are in the conducting state, and the voltage spike generated is large, requiring the varistor unit 503 to discharge the voltage. At this time, the first varistor R5 and the second varistor R6 consume the voltage spike. When the voltage spike is discharged to a level lower than the varistor, the varistor unit 503 switches from the conducting state to the cutoff state, and uses the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, and the first capacitor C1 to continuously consume the voltage spike until the voltage spike is completely consumed.

[0099] The spike voltage absorption circuit 105 provided in this embodiment includes an absorption unit 501, an energy storage unit 502, a varistor unit 503, and a rectifier bridge 504. The spike voltage absorption circuit 104 is connected between a first node A and a second node B. The two AC input terminals of the rectifier bridge 504 are respectively connected to the first node A and the second node B. The varistor unit 503, the energy storage unit 502, and the absorption unit 501 are connected in parallel between the two DC output terminals of the rectifier bridge 504. Based on the amplitude of the spike voltage generated in the circuit, and combined with the varistor voltage of the varistor unit 503, different electronic devices are dynamically used to discharge the spike voltage, thereby achieving complete consumption of the spike voltage, improving the overall efficiency of the inverter, reducing the probability of damage to the switching devices in the AC conversion circuit 104, improving the reliability of the inverter, reducing power device losses, reducing the safety risks caused by spike voltage, and reducing maintenance costs.

[0100] Obviously, the embodiments described above are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0101] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the utility models disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0102] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A spike voltage absorption circuit, characterized in that, The spike voltage absorption circuit is connected between the first node and the second node, and the spike voltage absorption circuit includes: a rectifier bridge, a varistor unit, an energy storage unit, and an absorption unit; The two AC input terminals of the rectifier bridge are connected to the first node and the second node respectively, and the varistor unit, the energy storage unit and the absorption unit are connected in parallel between the two DC output terminals of the rectifier bridge.

2. The spike voltage absorption circuit according to claim 1, characterized in that, The varistor unit includes one or more varistors connected in parallel, and the one or more varistors connected in parallel are connected between the two DC output terminals of the rectifier bridge.

3. The spike voltage absorption circuit according to claim 1, characterized in that, The energy storage unit includes one or more first capacitors connected between the two DC output terminals of the rectifier bridge.

4. The spike voltage absorption circuit according to claim 1, characterized in that, The absorption unit includes one or more resistors connected in series, which are connected between the two DC output terminals of the rectifier bridge.

5. The spike voltage absorption circuit according to any one of claims 1-4, characterized in that, The rectifier bridge includes a first diode, a second diode, a third diode, and a fourth diode; The anode of the first diode and the cathode of the second diode are both connected to the first node; The anode of the third diode and the cathode of the fourth diode are both connected to the second node; The cathodes of the first diode and the third diode are both connected to the first DC output terminal of the two DC output terminals of the rectifier bridge. The anodes of the second diode and the fourth diode are both connected to the second DC output terminal of the two DC output terminals of the rectifier bridge.

6. The spike voltage absorption circuit according to any one of claims 1-4, characterized in that, The resistance of the absorption unit is greater than the resistance of the varistor unit in the on state.

7. The spike voltage absorption circuit according to any one of claims 1-4, characterized in that, The resistance of the absorption unit is less than the resistance of the varistor unit in the off state.

8. An inverter, characterized in that, Includes an AC conversion circuit and a spike voltage absorption circuit as described in any one of claims 1-7; The two AC input terminals of the AC conversion circuit are the first node and the second node, respectively.

9. The inverter according to claim 8, characterized in that, Also includes: Isolation transformer; The secondary side of the isolation transformer is connected to the two AC input terminals of the AC conversion circuit.

10. The inverter according to claim 9, characterized in that, Also includes: At least one DC-AC converter circuit; The AC output terminal of the DC-AC conversion circuit is connected to the primary side of the isolation transformer, and the DC input terminal of the DC-AC conversion circuit is connected to the DC power supply.

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