Power converter

Abstract

The utility model discloses a power converter, which relates to the field of power conversion, and is characterized in that a rectifying circuit is connected with an alternating current power supply, converts the alternating current power supply into a direct current power supply and outputs the direct current power supply to two ends of a first capacitor, and a primary winding of a transformer, a power switch tube and an output protection module are connected in series; the power switch tube converts direct-current power at the two ends of the first capacitor into alternating-current power again to facilitate voltage level adjustment of the transformer, the output protection module is connected in series in the loop, and when the power switch tube fails and is damaged, current in the loop is increased rapidly, and the output protection module is disconnected. When the current in the loop is greater than a preset value, the output protection module disconnects the circuit between the series loop and the first capacitor quickly to prevent the direct-current power stored in the first capacitor from being continuously output to the series loop, so that the large current at the short circuit moment is avoided, the fault is controlled within the minimum range, and the service life is prolonged. The huge risk of circuit explosion and fire is avoided, subsequent maintenance and circuit recovery are facilitated, and the safety and reliability of the whole power converter are improved.

Description

Technical Field

[0001] The utility model relates to the field of power conversion, and particularly to a power converter. Background Art

[0002] With the continuous development of various electrical appliances, the application of power converters is becoming more and more extensive, and users' requirements for power converters are also getting higher and higher. In a power converter, series-connected power switching tubes and a transformer are usually used to realize the voltage level conversion process. The two ends of the series circuit are connected to the front-end DC power supply. The DC power is converted into AC power by the on and off of the power switching tubes, and the AC power is then stepped up or down through the transformer.

[0003] However, during the operation of a power converter, especially a high-voltage power converter, the working environment of the power switching tubes is mostly in a state of high voltage, high temperature and large current, resulting in the power switching tubes working in an environment of maximum stress for a long time. They are the most easily damaged components in the entire power converter. The failure and damage of the power switching tubes will cause abnormal short circuits in the circuit. After the short circuit occurs, the internal resistance of the short-circuit loop is very small. The voltage across the two ends of the DC power supply connected to the power switching tubes passes through the short-circuit loop. Especially when the voltage across the two ends of the DC power supply is very large, the output of the DC power supply will cause a current of up to several hundred or even thousands of amperes to appear in the loop instantly during the short circuit, resulting in a huge risk of violent explosion and fire of the power switching tubes. At the same time, it will further damage the front-end DC circuit, and then cause the entire power converter to be scrapped, posing a great safety hazard. How to avoid this safety hazard has become an urgent technical problem to be solved in the current power converter. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a power converter. An output protection module is connected in series in the loop. When the current in the loop is greater than a preset value, the circuit between this series loop and the first capacitor is quickly disconnected, preventing the DC power stored in the first capacitor from continuing to be output to the series loop, thereby avoiding the large current during the short circuit, controlling the fault within the smallest range, avoiding the huge risk of circuit explosion and fire, facilitating subsequent maintenance and circuit recovery, and improving the safety and reliability of the entire power converter.

[0005] To solve the above technical problems, the utility model provides a power converter, including:

[0006] A rectification circuit, the input end of which is connected to an AC power supply, and is used for converting the AC power supply into a DC power supply;

[0007] A first capacitor connected in parallel between the two output ends of the rectification circuit;

[0008] A transformer, the first end of the primary winding is respectively connected to the first output end of the rectifier circuit and the first end of the first capacitor, and the secondary winding serves as the output end of the power converter;

[0009] A power switch transistor, the first end is connected to the second end of the primary winding of the transformer, and the second end is respectively connected to the second output end of the rectifier circuit and the second end of the first capacitor;

[0010] An output protection module connected in series with the power switch transistor, configured to cut off the circuit connection between the first capacitor and the power switch transistor when the current flowing through the power switch transistor is greater than a preset value.

[0011] Optionally, the output protection module includes a first protection sub-module and / or a second protection sub-module;

[0012] The first end of the first protection sub-module is respectively connected to the first output end of the rectifier circuit and the first end of the first capacitor, and the second end is connected to the first end of the primary winding of the transformer;

[0013] The first end of the second protection sub-module is respectively connected to the second output end of the rectifier circuit and the second end of the first capacitor, and the second end is connected to the second end of the power switch transistor.

[0014] Optionally, the first protection sub-module is a fuse.

[0015] Optionally, the power converter further includes a second capacitor, the first end of the second capacitor is respectively connected to the second end of the fuse and the first end of the primary winding of the transformer, and the second end is respectively connected to the second end of the power switch transistor, the second output end of the rectifier circuit and the second end of the first capacitor.

[0016] Optionally, the power converter further includes a first unidirectional conduction module, the negative electrode of the first unidirectional conduction module is respectively connected to the first end of the primary winding of the transformer, the first output end of the rectifier circuit and the first end of the first capacitor, and the positive electrode is respectively connected to the first end of the power switch transistor and the second end of the primary winding of the transformer.

[0017] Optionally, the power converter further includes a second unidirectional conduction module, the positive electrode of the second unidirectional conduction module is connected to one end of the secondary winding of the transformer, the negative electrode serves as the first output end of the power converter, and the other end of the secondary winding of the transformer serves as the second output end of the power converter.

[0018] Optionally, the power converter further includes a filter, the input end of the filter is connected to an AC power supply, and the output end is connected to the input end of the rectifier circuit.

[0019] Optionally, the rectification circuit includes:

[0020] A first diode;

[0021] A second diode, the cathode of which is connected to the anode of the first diode and serves as the first output terminal of the rectification circuit;

[0022] A third diode, the anode of which is respectively connected to the anode of the second diode and the second output terminal of the filter;

[0023] A fourth diode, the anode of which is connected to the cathode of the third diode and serves as the second output terminal of the rectification circuit, and the cathode of which is respectively connected to the cathode of the first diode and the first output terminal of the filter.

[0024] Optionally, the power converter further includes a third capacitor. The first end of the third capacitor is respectively connected to the neutral line of the AC power supply and the first input terminal of the filter, and the second end of the third capacitor is respectively connected to the live wire of the AC power supply and the second input terminal of the filter.

[0025] Optionally, the power converter further includes an input protection module. The first end of the input protection module is connected to the live wire of the AC power supply, and the second end of the input protection module is respectively connected to the second end of the third capacitor and the second input terminal of the filter.

[0026] The present utility model provides a power converter, which includes a rectification circuit, a first capacitor, a transformer, a power switch tube and an output protection module. The rectification circuit is connected to an AC power supply and converts it into a DC power supply and outputs it to both ends of the first capacitor. The primary winding of the transformer, the power switch tube and the output protection module are connected in series. The power switch tube reconverts the DC power supply at both ends of the first capacitor into an alternating current to facilitate the transformer to adjust the voltage level. The output protection module is connected in series in the loop. When the power switch tube fails and is damaged, the current in the loop increases rapidly. When the current in the loop is greater than a preset value, the output protection module quickly disconnects the circuit between this series loop and the first capacitor, preventing the DC power supply stored in the first capacitor from continuing to be output to the series loop, thereby avoiding the large current at the moment of short circuit, controlling the fault within the smallest range, avoiding the huge risk of circuit explosion and fire, facilitating subsequent maintenance and circuit restoration, and improving the safety and reliability of the entire power converter. Description of the Drawings

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required in the prior art and the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0028] Figure 1 Schematic diagram of the structure of a power converter provided by the present invention;

[0029] Figure 2 Schematic diagram of the structure of another power converter provided by the present invention. Specific embodiments

[0030] The core of the present invention is to provide a power converter. The output protection module is connected in series in the circuit. When the current in the circuit is greater than the preset value, the circuit between this series circuit and the first capacitor is quickly disconnected, preventing the DC power stored in the first capacitor from continuing to be output to the series circuit, thereby avoiding the large current at the moment of short circuit, controlling the fault within the smallest range, avoiding the huge risk of circuit explosion and fire, facilitating subsequent maintenance and circuit restoration, and improving the safety and reliability of the entire power converter.

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0032] Please refer to Figure 1 , Figure 1 Schematic diagram of the structure of a power converter provided by the present invention; Please refer to Figure 2 , Figure 2 Schematic diagram of the structure of another power converter provided by the present invention; L represents the live wire of the AC power supply, N represents the neutral wire of the AC power supply, the AC power supply is an AC input of 220V, and DC300V represents that the DC power output by the rectifier circuit is 300V DC. To solve the above technical problems, the present invention provides a power converter, including:

[0033] A rectifier circuit 1, with its input end connected to the AC power supply, for converting the AC power supply into a DC power supply;

[0034] A first capacitor C1 connected in parallel between the two output ends of the rectifier circuit 1;

[0035] A transformer T1, the first end of the primary winding is respectively connected to the first output end of the rectification circuit 1 and the first end of the first capacitor C1, and the secondary winding serves as the output end of the power converter;

[0036] A power switch tube Q, the first end is connected to the second end of the primary winding of the transformer T1, and the second end is respectively connected to the second output end of the rectification circuit 1 and the second end of the first capacitor C1;

[0037] An output protection module 2 connected in series with the power switch tube Q, which is used to cut off the circuit connection between the first capacitor C1 and the power switch tube Q when the current flowing through the power switch tube Q is greater than a preset value.

[0038] Specifically, the power converter can convert an AC power supply into an AC power supply or a DC power supply required by the user. In this process, in order to make the output voltage and frequency possibly set according to the user's needs, it is necessary to first convert the AC power supply into a DC power supply by using the rectification circuit 1, and then use the power switch tube Q and the transformer T1 to realize the adjustment of the voltage magnitude and frequency of the output voltage. The transformer T1 works normally in the state of input AC power, so it is necessary to use the on and off processes of the power switch tube Q to convert the DC power output by the rectification circuit 1 back into AC power. At the same time, by adjusting the duty cycle of the on process of the power switch tube Q, the adjustment of the frequency of the output voltage can also be realized. Therefore, the AC power supply is converted into a DC power supply by the rectification circuit 1, and a first capacitor C1 connected in parallel between the two output ends of the rectification circuit 1 is provided to play the role of energy storage and filtering. Then, the DC power supply is converted back into AC power through the on and off processes of the power switch tube Q and input into the transformer T1. After the transformer T1 steps up or down the voltage, it outputs the AC power required by the user.

[0039] Furthermore, when the power switch tube Q is damaged, a short circuit will occur at both ends of the series circuit of the transformer T1 and the power switch tube Q and the secondary winding of the transformer T1. At this time, the current in the series circuit will increase rapidly. Therefore, the present application provides an output protection module 2 connected in series with the power switch tube Q, which disconnects the circuit connection when the current flowing through the power switch tube Q is greater than a preset value, so that the connection between the first capacitor C1 and the series circuit is disconnected, and the DC power supply at both ends of the first capacitor C1 is prevented from continuing to be output to the short-circuited series circuit, thereby avoiding safety hazards such as violent explosion and fire caused by the large current at the moment of short circuit.

[0040] It is not difficult to understand that when the power switch tube Q is damaged, the output protection module 2 cuts off the circuit in time, so that the damaged devices are only the power switch tube Q and the output protection module 2. The fault range is small and very easy to repair, avoiding the huge risk of the power switch tube Q exploding and catching fire. Even if device damage occurs due to a short circuit during the production and use stages, the loss of the entire power converter is small, the fault range is controlled within the minimum range, avoiding the huge risk of the circuit exploding and catching fire, and the repair is more convenient.

[0041] It should be noted that the specific types and implementation methods of the rectifier circuit 1, the first capacitor C1, the transformer T1, the power switch tube Q, and the output protection module 2 are not particularly limited in this application. The rectifier circuit 1 can use a rectifier bridge or other methods to achieve the rectification process of the AC power supply; the turns ratio of the transformer T1 can be adjusted and set according to the specific magnitude of the output voltage required by the user; the specific duty cycle of the drive signal for controlling the on and off of the power switch tube Q can be set according to the frequency magnitude of the output voltage required by the user. A controller can be added to implement the control process of the power switch tube Q, or a drive chip can be directly used to implement the control of the power switch tube Q. The specific types and implementation methods of the drive signal required for the power switch tube Q are not particularly limited in this application; the output protection module 2 can be implemented using overcurrent protection devices such as fuses and fuse wires, and can be specifically selected and set according to the application scenario of the power converter; when the power converter is applied in a low-voltage environment, a fuse wire can be used as the output protection module 2, and in a high-voltage environment, a safety fuse is usually used to implement the output protection module 2.

[0042] Furthermore, the capacitance of the first capacitor C1 can be selected and set according to the application scenario of the power converter. When the required output voltage of the voltage converter is relatively large, the capacitance of the first capacitor C1 can be appropriately increased and implemented using a large-capacitance capacitor. When the required output voltage of the voltage converter is relatively small, the capacitance of the first capacitor C1 can be appropriately decreased; the output protection module 2 only needs to be connected in series in the series circuit of the primary winding of the transformer T1 and the power switch tube Q, and the specific installation position can be adjusted according to the actual circuit conditions. The specific value of the preset value and so on are not particularly limited in this application and can be set according to the normal current range of the current during the normal operation of the power converter.

[0043] It is not difficult to understand that the power converter provided by the present utility model can be applied in fields such as power electronics communication engineering, photovoltaic power generation, and electric vehicle charging piles. It solves the technical problems of explosion and fire in the production and use of power converters and the resulting infinite destructive ability, and is particularly suitable for power converters with large-capacity high-voltage filter energy storage capacitors at the front end, avoiding serious safety hazards caused by short circuits in the power converter under high-voltage conditions. The power converter provided by the present utility model is also particularly suitable for use in special environments such as hospitals, schools, high-speed rails, and aircraft where abnormal explosion sounds need to be avoided and ignition sources need to be eliminated.

[0044] The present utility model provides a power converter, which includes a rectifier circuit 1, a first capacitor C1, a transformer T1, a power switch tube Q, and an output protection module 2. The rectifier circuit 1 is connected to an AC power supply and converts it into a DC power supply and outputs it to both ends of the first capacitor C1. The primary winding of the transformer T1, the power switch tube Q, and the output protection module 2 are connected in series. The power switch tube Q reconverts the DC power supply at both ends of the first capacitor C1 into an alternating current to facilitate the transformer T1 to adjust the voltage level. The output protection module 2 is connected in series in the loop. When the power switch tube Q fails and is damaged, the current in the loop increases rapidly. When the current in the loop is greater than a preset value, the output protection module 2 quickly disconnects the circuit between this series loop and the first capacitor C1, preventing the DC power supply stored in the first capacitor C1 from continuing to be output to the series loop, thereby avoiding the large current at the moment of short circuit, controlling the fault within the smallest range, avoiding the huge risk of circuit explosion and fire, facilitating subsequent maintenance and circuit recovery, and improving the safety and reliability of the entire power converter.

[0045] Based on the above embodiments:

[0046] As an optional embodiment, the output protection module 2 includes a first protection sub-module and / or a second protection sub-module;

[0047] The first end of the first protection sub-module is respectively connected to the first output end of the rectifier circuit 1 and the first end of the first capacitor C1, and the second end is connected to the first end of the primary winding of the transformer T1;

[0048] The first end of the second protection sub-module is respectively connected to the second output end of the rectifier circuit 1 and the second end of the first capacitor C1, and the second end is connected to the second end of the power switch tube Q.

[0049] It can be understood that, in order to further improve the safety of the entire circuit, a first protection sub-module and a second protection sub-module can be provided in the series loop to ensure that the output protection module 2 can effectively cut off the circuit between the DC power supply and the series loop in the case of a short circuit. The two protection sub-modules cooperate with each other. In the case where the power switch tube Q is damaged, both protection sub-modules perform the action of cutting off the circuit, avoiding the situation where the circuit cannot be cut off when one of the protection sub-modules fails; alternatively, only the first protection sub-module or the second protection sub-module can be provided in the series circuit. The first protection sub-module and / or the second protection sub-module can be provided at a position directly connected to the first capacitor C1, so that the connection line between the first capacitor C1 and the series loop can be directly cut off when the circuit is cut off. The specific types and implementation manners of the first protection sub-module and the second protection sub-module are not particularly limited in this application. The two can be implemented by using the same type of device, or two types of devices can be set according to application requirements to further ensure that the circuit can be effectively cut off in the case of a short circuit from two positions.

[0050] Specifically, by directly connecting the output protection module 2 to the first end and / or the second end of the first capacitor C1, it can be ensured that the circuit connection between the first capacitor C1 and the series loop can be effectively disconnected during the process of the output protection module 2 cutting off the line; at the same time, multiple protection sub-modules can be set according to application requirements to improve the accuracy and reliability of the entire output protection module 2 and ensure the safety of the entire power converter.

[0051] As an optional embodiment, the first protection sub-module is a fuse F1.

[0052] It is not difficult to understand that the first protection sub-module can be implemented by using a fuse F1. A safety fuse F1 is connected in series between the first end of the first capacitor C1, that is, the positive output end of the DC power supply, and the first end of the primary winding of the transformer T1. The parameters of the fuse F1 are reasonably selected according to the load size of the power converter and the voltage at the specific position where it is set. This embodiment provides a layout position of the fuse F1 in the power converter. The front end of the fuse F1 is connected to a large-capacity energy storage capacitor, that is, the first capacitor C1, the back end is connected to the transformer T1, and finally connected to the power switch tube Q. The safety fuse F1 realizes over-current fusing in the case of a short circuit of the power switch tube Q, effectively cutting off the circuit connection between the first capacitor C1 and the transformer T1. The specific type and parameter value of the fuse F1 are not particularly limited in this application.

[0053] Specifically, by adding a fuse F1 between the first capacitor C1 and the primary winding of the transformer T1, the safety and reliability of the entire power converter are effectively improved, enabling the power converter to be safely and widely applied in a wider range of application scenarios. The devices used are easy to implement and the connection method is simple, which is conducive to the simple implementation of the entire power converter.

[0054] As an alternative embodiment, the power converter further includes a second capacitor C2. The first end of the second capacitor C2 is respectively connected to the second end of the fuse F1 and the first end of the primary winding of the transformer T1, and the second end is respectively connected to the second end of the power switch tube Q, the second output end of the rectifier circuit 1, and the second end of the first capacitor C1.

[0055] Furthermore, due to the addition of the fuse F1 between the first capacitor C1 and the transformer T1, the circuit path from the first end of the first capacitor C1, i.e., the A end, to the first end of the primary winding of the transformer T1, i.e., the 1 end, becomes longer. This may increase the parasitic inductance in the series loop. To eliminate the adverse effects such as interference caused by this parasitic inductance, a second capacitor C2 can be further connected in parallel to the series loop at the rear end of the fuse F1 as an anti-interference high-frequency capacitor. One end of the second capacitor C2 is connected to the 1 end of the transformer T1T1, and the other end is connected to the B end of the first capacitor C1. The A end of the first capacitor C1 is the first end of the first capacitor C1, and the B end is the second end of the first capacitor C1; the 1 end of the transformer T1 is the first end of the primary winding, the 4 end is the second end of the primary winding, the 2 is the first end of the secondary winding, and the 3 is the second end of the secondary winding. The specific type and implementation method of the second capacitor C2 are not particularly limited in this application, and the selection of its capacitance and withstand voltage can be determined according to the specific voltage conditions at the set position.

[0056] Specifically, to avoid the possible parasitic inductance caused by adding the fuse F1, a second capacitor C2 connected in parallel to the series loop can be further added between the fuse F1 and the transformer T1. The second capacitor C2 plays a filtering role, improving the anti-interference ability of the entire series loop and ensuring the accuracy and reliability of the output voltage of the entire power converter.

[0057] As an alternative embodiment, the power converter further includes a first unidirectional conduction module. The negative pole of the first unidirectional conduction module is respectively connected to the first end of the primary winding of the transformer T1, the first output end of the rectifier circuit 1, and the first end of the first capacitor C1, and the positive pole is respectively connected to the first end of the power switch tube Q and the second end of the primary winding of the transformer T1.

[0058] It is not difficult to understand that a reverse first unidirectional conduction module can be further added in parallel at both ends of the primary winding of the transformer T1 to absorb current, providing a current release loop for the inductance of the primary winding and avoiding problems such as high voltage and device damage caused by the release of inductive current. The specific type and implementation method of the first unidirectional conduction module are not particularly limited in this application. Usually, a diode can be used to implement it, and a diode is connected in parallel at both ends of the primary winding of the transformer T1 as an absorption diode.

[0059] Specifically, by further connecting a reverse first unidirectional conduction module in parallel, the potential safety hazard caused by the high voltage that may be generated during the process of the primary winding of the transformer T1 releasing current itself can be avoided. The circuit structure is simple and easy to implement, further improving the safety and reliability of the transformer T1 and ensuring the safe operation of the entire power converter.

[0060] As an alternative embodiment, the power converter further includes a second unidirectional conduction module. The positive electrode of the second unidirectional conduction module is connected to one end of the secondary winding of the transformer T1, and the negative electrode serves as the first output terminal of the power converter. The other end of the secondary winding of the transformer T1 serves as the second output terminal of the power converter.

[0061] It can be understood that the power converter can be used to convert an AC power supply into another AC power supply with different voltage levels, or it can also be used to convert an AC power supply into a DC power supply with different voltage levels. If the power converter needs to output an AC power supply required by the user, the secondary winding of the transformer T1 can be directly used as the output terminal of the power converter. If the power converter needs to output a DC power supply required by the user, a second unidirectional conduction module needs to be added at one end of the secondary winding of the transformer T1 to convert the AC power supply output by the transformer T1 into the DC power supply required by the user. At this time, the negative electrode of the second unidirectional conduction module is the first output terminal of the power converter, and the other end of the secondary winding of the transformer T1 is the second output terminal of the power converter. The specific type and implementation method of the second unidirectional conduction module are not particularly limited in this application. Usually, a diode can be used to implement it.

[0062] Specifically, a second unidirectional conduction module can be further added on the basis of the secondary winding of the transformer T1 to realize the output process of the DC power supply required by the user. The circuit structure is simple and easy to implement, further expanding the application range of the power converter and improving the flexibility of the entire power converter.

[0063] As an alternative embodiment, the power converter further includes a filter T2. The input terminal of the filter T2 is connected to the AC power supply, and the output terminal is connected to the input terminal of the rectification circuit 1.

[0064] It is not difficult to understand that during the process of converting an AC power supply into a DC power supply, in order to improve the stability of the finally output DC power supply and avoid excessive noise and interference signals, a filter T2 connected in series with the rectifier circuit 1 can also be added to implement the filtering process. In this embodiment, the filter T2 is arranged between the rectifier circuit 1 and the AC power supply. The specific type, implementation method, and setting position of the filter T2 are not particularly limited in this application.

[0065] Specifically, the filter T2 can be further added to improve the accuracy and stability of the DC power supply finally output by the rectifier circuit 1. The filter T2 can effectively filter out noise and interference signals in the AC power supply, etc., to ensure the accuracy and stability of the finally output voltage of the entire power converter.

[0066] As an optional embodiment, the rectifier circuit 1 includes:

[0067] The first diode D1;

[0068] The second diode D2, the cathode of which is connected to the anode of the first diode D1 and serves as the first output terminal of the rectifier circuit 1;

[0069] The third diode D3, the anode of which is respectively connected to the anode of the second diode D2 and the second output terminal of the filter T2;

[0070] The fourth diode D4, the anode of which is connected to the cathode of the third diode D3 and serves as the second output terminal of the rectifier circuit 1, and the cathode is respectively connected to the cathode of the first diode D1 and the first output terminal of the filter T2.

[0071] It is not difficult to understand that the rectifier circuit 1 can be implemented by using a bridge rectifier module composed of the first diode D1, the second diode D2, the third diode D3, and the fourth diode D4. The bridge rectifier module consists of four diodes connected in a closed-loop "bridge" configuration to generate the required output, without the need for a special center-tapped transformer T1, thus reducing the size and cost. The specific type and implementation method of the first diode D1, the second diode D2, the third diode D3, and the fourth diode D4 are not particularly limited in this application.

[0072] Specifically, a bridge rectifier module composed of four diodes can be used to implement the rectifier circuit 1 required by the power converter. The entire circuit structure is simple, easy to implement, and the components used have low cost and small volume, which is beneficial to the simple implementation of the entire power converter.

[0073] As an alternative embodiment, the power converter further includes a third capacitor C3. The first end of the third capacitor C3 is respectively connected to the neutral line of the AC power supply and the first input end of the filter T2, and the second end is respectively connected to the live wire of the AC power supply and the second input end of the filter T2.

[0074] It is not difficult to understand that, in order to avoid excessive signal disturbances in the AC power supply, especially when the AC power supply directly uses the power grid, in order to avoid the influence of the voltage fluctuation of the power grid on the working process of the entire power converter, a third capacitor C3 can be further added between the filter T2 and the AC power supply to play a role in filtering and anti-interference, and avoid the influence of the voltage fluctuation of the AC power supply on the working process of the power converter. The specific type and implementation method of the third capacitor C3 are not particularly limited in this application.

[0075] Specifically, a third capacitor C3 can also be added to avoid the influence of the interference of the AC power supply on the working process of the power converter, further improve the accuracy and reliability of the output voltage of the rectifier circuit 1, and improve the accuracy and reliability of the output voltage of the entire power converter.

[0076] As an alternative embodiment, the power converter further includes an input protection module. The first end of the input protection module is connected to the live wire of the AC power supply, and the second end is respectively connected to the second end of the third capacitor C3 and the second input end of the filter T2.

[0077] It is not difficult to understand that considering that the abnormally large voltage or current output by the AC power supply will also pose a safety hazard to the power converter, an input protection module can also be added to the input side of the power converter. The input protection module can cut off the circuit connection between the AC power supply and the entire power converter when the voltage and / or current output by the AC power supply is too large, avoid damage to the power converter caused by the abnormality of the AC power supply, and further improve the safety and reliability of the entire power converter. The specific type and implementation method of the input protection module are not particularly limited in this application. It can be implemented by protection devices such as fuses. In this embodiment, it is set on the connection line between the live wire of the AC power supply and the power converter, and it can also be set on the connection line between the neutral line of the AC power supply and the voltage converter. The specific setting position can also be adjusted and set according to the actual application situation. As Figure 2 shown, a fuse F2 can be set as the input protection module.

[0078] Specifically, an input protection module can also be added to avoid the safety hazards caused by the AC power supply. The output protection module 2 and the input protection module cooperate with each other to achieve multi-faceted protection of the entire power converter from the perspectives of AC input and DC output, improve the safety and reliability of the entire power converter, and ensure the normal working process of the power converter.

[0079] In this specification, the various embodiments are described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the similarities and common parts among the embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method section.

[0080] It should also be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0081] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power converter, characterized in that: include: A rectifier circuit, the input end of which is connected to an AC power source and is used to convert the AC power source into a DC power source; A first capacitor connected in parallel between two output terminals of the rectifier circuit; A transformer, wherein the first end of the primary winding is respectively connected to the first output end of the rectifier circuit and the first end of the first capacitor, and the secondary winding serves as the output end of the power converter; A power switch tube, a first end of which is connected to the second end of the primary winding of the transformer, and a second end of which is respectively connected to the second output end of the rectifier circuit and the second end of the first capacitor; The output protection module connected in series with the power switch tube is used to cut off the circuit connection between the first capacitor and the power switch tube when the current flowing through the power switch tube is greater than a preset value.

2. The power converter according to claim 1, wherein: The output protection module includes a first protection submodule and / or a second protection submodule; The first end of the first protection submodule is connected to the first output end of the rectifier circuit and the first end of the first capacitor respectively, and the second end is connected to the first end of the primary winding of the transformer; The first end of the second protection submodule is connected to the second output end of the rectifier circuit and the second end of the first capacitor respectively, and the second end is connected to the second end of the power switch tube.

3. The power converter according to claim 2, wherein: The first protection submodule is a fuse.

4. The power converter according to claim 3, wherein: The power converter also includes a second capacitor, a first end of which is respectively connected to the second end of the fuse and the first end of the primary winding of the transformer, and a second end of which is respectively connected to the second end of the power switch tube, the second output end of the rectifier circuit and the second end of the first capacitor.

5. The power converter according to claim 1, wherein: The power converter also includes a first unidirectional conduction module, a negative pole of which is respectively connected to the first end of the primary winding of the transformer, the first output end of the rectifier circuit and the first end of the first capacitor, and a positive pole of which is respectively connected to the first end of the power switch tube and the second end of the primary winding of the transformer.

6. The power converter according to claim 1, wherein: The power converter also includes a second unidirectional conduction module, the positive pole of the second unidirectional conduction module is connected to one end of the secondary winding of the transformer, the negative pole serves as the first output end of the power converter, and the other end of the secondary winding of the transformer serves as the second output end of the power converter.

7. The power converter according to any one of claims 1 to 6, characterized in that: The power converter further comprises a filter, wherein an input end of the filter is connected to an AC power source, and an output end of the filter is connected to an input end of the rectifier circuit.

8. The power converter according to claim 7, wherein: The rectifier circuit comprises: a first diode; a second diode, a cathode of which is connected to the anode of the first diode and serves as a first output terminal of the rectifier circuit; a third diode, an anode of which is respectively connected to the anode of the second diode and the second output end of the filter; The fourth diode has an anode connected to the cathode of the third diode and serves as the second output end of the rectifier circuit, and a cathode connected to the cathode of the first diode and the first output end of the filter respectively.

9. The power converter according to claim 8, characterized in that: The power converter also includes a third capacitor, a first end of the third capacitor is respectively connected to the neutral line of the AC power supply and the first input end of the filter, and a second end of the third capacitor is respectively connected to the live line of the AC power supply and the second input end of the filter.

10. The power converter according to claim 9, wherein: The power converter further comprises an input protection module, a first end of which is connected to the live wire of the AC power source, and a second end of which is respectively connected to the second end of the third capacitor and the second input end of the filter.

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