CN118282224A

CN118282224A - Inverter circuit with thyristor protection and converter device

Info

Publication number: CN118282224A
Application number: CN202410378401.4A
Authority: CN
Inventors: 张增高; 何江; 李梓涵; 成正梁
Original assignee: Shenzhen Megarevo Technology Co ltd
Current assignee: Shenzhen Megarevo Technology Co ltd
Priority date: 2024-03-29
Filing date: 2024-03-29
Publication date: 2024-07-02

Abstract

The application relates to the technical field of converters, in particular to an inverter circuit with thyristor protection and a converter device, wherein the circuit comprises a parallel-off-grid switching module and a rectifying inverter module; the grid-connected/off-grid switching module comprises an input end, a grid-connected end and an output end, wherein the input end of the grid-connected/off-grid switching module is used for receiving an alternating current signal output by the alternating current output end, the grid-connected end is connected to a public power grid, and the output end is connected with a load; the off-grid switching module further comprises a thyristor and a current limiting element, wherein the thyristor is connected in series at the joint of the input end and the grid-connected end and is used for controlling the switching of the off-grid working condition; the current limiting element is connected in series at the connection part of the input end and the grid-connected end and is used for limiting the current peak generated by the switching of the off-grid working conditions so as to protect the thyristor. The application can limit the current peak generated by the converter in the switching state so as to protect the thyristor from breakdown damage of the current peak.

Description

Inverter circuit with thyristor protection and converter device

Technical Field

The application relates to the technical field of converters, in particular to an inverter circuit with thyristor protection and a converter device.

Background

A thyristor (SCR) is a type of thyristor device that can be turned on and off by a control input signal. This makes them very suitable for use in converters, which can handle relatively high voltages and currents, are relatively simple in construction and are relatively economical components, as a semiconductor device, which has no mechanically moving parts compared to electromagnetic contactors. Electromagnetic contactors typically include an electromagnetic coil and a mechanical contact, the action of which involves a change in the magnetic field of the electromagnetic coil and movement of the mechanical contact. In contrast, thyristors only involve the change of the electrical characteristics of the semiconductor material, and have no mechanical movement, so that the response speed is faster, and the thyristors are very suitable for grid-connected and off-grid components of the energy storage converter. However, in the converter, the front end of the thyristor of the off-grid switching component is provided with a breaker, and the switch has voltage and current spikes at the moment of action or spike current possibly generated by equipment faults, which may cause the damage of the thyristor, and how to avoid the situation of the damage of the thyristor caused by overcurrent is a technical problem to be solved urgently.

Disclosure of Invention

The embodiment of the application provides an inverter circuit with thyristor protection and a converter device, which can realize the beneficial effects of limiting the current peak generated by a converter in switching state so as to protect the thyristor from breakdown damage of the current peak.

The first aspect of the application provides an inverter circuit with thyristor protection: an inverter circuit with thyristor protection comprises a parallel-off-grid switching module and a rectifying inverter module;

The rectification inversion module comprises a direct current input end and an alternating current output end, wherein the direct current input end is used for receiving an external direct current signal, and the rectification inversion module is used for rectifying and inverting the direct current signal to obtain an alternating current signal;

the grid-connected and off-grid switching module comprises an input end, a grid-connected end and an output end, wherein the input end of the grid-connected and off-grid switching module is used for receiving the alternating current signal output by the alternating current output end, the grid-connected end is used for being connected with an external public power grid, and the output end of the grid-connected and off-grid switching module is connected with an external load;

The grid-connected/off-grid switching module further comprises a thyristor and a current limiting element, wherein the thyristor is connected in series at the joint of the input end and the grid-connected end and is used for controlling whether the grid-connected/off-grid switching module is connected with the public power grid or not so as to control the switching of the working condition of the grid-connected/off-grid;

the current limiting element is connected in series at the connection part of the input end and the grid-connected end and is used for limiting a current peak generated by the switching of the off-grid working conditions so as to protect the thyristor.

By adopting the technical scheme, the rectification inversion module is used for rectifying and inverting the externally received direct current signal into the alternating current signal, the alternating current signal can be output to the public power grid besides being output to the load, whether the alternating current signal is output to the public power grid or not is determined by the grid-connected/off-grid switching module, if the alternating current signal is connected to the public power grid, the grid-connected/off-grid switching module is in a grid-connected state, otherwise, the grid-connected/off-grid switching is controlled by the thyristor, the thyristor can generate a current peak when controlling the grid-connected/off-grid switching, and the current peak is limited by the current limiting element to change the current, so that the thyristor is protected.

Optionally, the system further comprises a direct current control module;

the direct current control module comprises a battery input end, a bus end and a direct current output end, wherein the battery input end is used for receiving an input direct current signal of an external battery;

the bus end is used for receiving an input direct current signal of the external battery so as to balance the voltages of the external battery and the bus, and the direct current output end is used for outputting the voltage of the bus to the direct current input end of the rectifying and inverting module.

Through adopting above-mentioned technical scheme, the direct current control module balances the voltage of battery input and bus-bar to avoid producing too big electric current impact when using because of the voltage is uneven, supply the direct current signal by the bus-bar after balancing, output to rectification inversion module, so that rectification inversion module carries out inversion treatment to the direct current signal, obtains alternating current signal.

Optionally, the direct current control module further comprises a soft start unit, wherein the soft start unit comprises a first line and a second line;

the first circuit is used for balancing the voltages of the external battery and the bus and controlling the second circuit to be conducted after the voltages are balanced; the second circuit is used for controlling the direct current inversion module to conduct rectification inversion.

By adopting the technical scheme, the soft start unit is adopted for pre-starting, when the converter is started, the battery voltage is pre-charged for the bus through the first circuit, and when the battery voltage is balanced with the bus voltage, the second circuit is conducted to control the rectification inversion module to be started.

Optionally, the rectification inversion module comprises an IGBT unit;

the IGBT unit comprises a first phase bridge arm, a second phase bridge arm and a third phase bridge arm, wherein the first phase bridge arm comprises a first upper bridge and a first lower bridge, the second phase bridge arm comprises a second upper bridge and a second lower bridge, and the third phase bridge arm comprises a third upper bridge and a third lower bridge;

the collectors of the first upper bridge, the second upper bridge and the third upper bridge are connected with the positive electrode of the bus, and the emitters of the first lower bridge, the second lower bridge and the third lower bridge are connected with the negative electrode of the bus;

The collector of the first lower bridge is connected with the emitter of the first upper bridge, the collector of the second lower bridge is connected with the emitter of the second upper bridge, and the collector of the third lower bridge is connected with the emitter of the third upper bridge;

The gates of the first upper bridge, the second upper bridge, the third upper bridge, the first lower bridge, the second lower bridge and the third lower bridge respectively receive external gate signals so as to control the IGBT unit to longitudinally commutate according to the gate signals.

By adopting the technical scheme, the first phase bridge arm, the second phase bridge arm and the third phase bridge arm form a three-phase bridge arm, the three-phase bridge arms are respectively controlled by external grid signals, each pair of bridge arms is conductive by 180 degrees, the upper and lower two bridge arms of the same phase are alternately conductive, the angle difference of each phase for starting to conduct is 120 degrees, three bridge arms are conducted at any moment, and each commutation is carried out between the upper and lower two arms of the same phase, so that the three-phase difference 120-degree alternating current signal can be rectified conveniently.

Optionally, the rectification inversion module further comprises a transformation unit, and the transformation unit comprises a first winding, a second winding and a third winding;

the first end of the primary side of the first winding is connected with the emitter of the first upper bridge, and the second end of the primary side of the first winding is connected with the collector of the third lower bridge;

the first end of the primary side of the second winding is connected with the emitter of the second upper bridge, and the second end of the primary side of the second winding is connected with the first end of the primary side of the first winding;

The first end of the primary side of the third winding is connected with the collector electrode of the third lower bridge, and the second end of the primary side of the third winding is connected with the first end of the primary side of the second winding;

The secondary side first end of the first winding is connected with the secondary side first end of the second winding and the secondary side first end of the third winding;

The second end of the secondary side of the first winding, the second end of the secondary side of the second secondary side winding and the second end of the secondary side of the third winding are connected with the input end of the off-grid switching module.

By adopting the technical scheme, the three windings of the transformer respectively correspond to the three-phase circuits, and the three windings are isolated and output through the transformer so as to obtain alternating current signals on the three-phase circuits and output the alternating current signals to the off-grid switching module.

Optionally, the rectifying inversion module further comprises an LC filter unit, wherein the LC filter unit comprises an ac filter capacitor, a first inductor, a second inductor and a third inductor;

The alternating current filter capacitor comprises three capacitors which are connected in parallel at the connection part of the second end of the secondary side of the first winding and the input end, the connection part of the second end of the secondary side of the second winding and the input end and the connection part of the second end of the secondary side of the third winding and the input end in a triangle connection way;

The first inductor is connected in series between the second end of the secondary side of the first winding and the input end, the second inductor is connected in series between the second end of the secondary side of the second winding and the input end, and the third inductor is connected in series between the second end of the secondary side of the third winding and the input end.

Through adopting above-mentioned technical scheme, through alternating current filter capacitor and three inductance combination, form the LC filter circuit to filtering harmonic, and providing reactive compensation, thereby ensure alternating current signal output's stability.

Optionally, the current limiting element is a fourth inductor, a fifth inductor and a sixth inductor;

The fourth inductor is connected in series between the first inductor and the thyristor, the fifth inductor is connected in series between the second inductor and the thyristor, and the sixth inductor is connected in series between the third inductor and the thyristor.

By adopting the technical scheme, the three circuits corresponding to the three-phase circuit arranged in front of the thyristor are respectively provided with the inductor, and the characteristic of the inductor which can resist the current change is utilized to inhibit and prevent the current peak possibly generated during off-grid switching, so that the surface thyristor is damaged.

The second aspect of the present application provides a converter device with thyristor protection, which is loaded with the inverter circuit with thyristor protection.

In summary, the present application includes at least one of the following beneficial effects:

1. The rectification inversion module is used for rectifying and inverting the externally received direct current signal into an alternating current signal, the alternating current signal can be output to a public power grid besides being output to a load, whether the alternating current signal is output to the public power grid or not is determined by the grid-connection and grid-disconnection switching module, if the alternating current signal is connected to the public power grid, the alternating current signal is in a grid-connection state, otherwise, the alternating current signal is in a grid-disconnection state, the grid-disconnection switching is controlled by a thyristor, a current peak is generated when the thyristor is controlled and switched off the grid, and the current peak is limited by a current limiting element to change the current, so that the effect of protecting the thyristor is achieved.

2. The direct current control module balances the voltage of the battery input end and the bus end, thereby avoiding overlarge current impact caused by uneven voltage when the direct current control module is used, the bus is used for supplying direct current signals after balancing and outputting the direct current signals to the rectification inversion module, so that the rectification inversion module inverts the direct current signals to obtain alternating current signals, the soft starting unit is adopted for pre-starting, when the converter is started, the battery voltage is pre-charged to the bus through the first circuit, and when the battery voltage is balanced with the bus voltage, the second circuit is conducted to control the rectification inversion module to be started.

3. The first phase bridge arm, the second phase bridge arm and the third phase bridge arm form a three-phase bridge arm, the three-phase bridge arms are respectively controlled by external grid signals, each pair of bridge arms is conductive by 180 degrees, the upper and lower bridge arms of the same phase are alternately conductive, the angle difference of each phase for starting to conduct is 120 degrees, three bridge arms are conducted at any moment, and each current conversion is carried out between the upper and lower arms of the same phase, so that the three-phase difference 120-degree alternating current signals can be rectified conveniently.

Drawings

Fig. 1 is a block diagram of an inverter circuit with thyristor protection according to an embodiment of the present application;

fig. 2 is a schematic circuit diagram of an inverter circuit with thyristor protection according to an embodiment of the present application.

Detailed Description

The following examples will assist those skilled in the art in further understanding the function of the present application, but are not intended to limit the application in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present application.

In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

It should be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It should also be understood that the term "and/or" as used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.

As used in the present description and the appended claims, the term "if" may be interpreted in context as "when …" or "once" or "in response to a determination" or "in response to detection. Similarly, the phrase "if a determination" or "if a [ described condition or event ] is detected" may be interpreted in the context of meaning "upon determination" or "in response to determination" or "upon detection of a [ described condition or event ]" or "in response to detection of a [ described condition or event ]".

Furthermore, the terms "first," "second," "third," and the like in the description of the present specification and in the appended claims, are used for distinguishing between descriptions and not necessarily for indicating or implying a relative importance.

Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.

In order to make the purposes, technical solutions and advantages of the present application more clear, the method for converting current with thyristor protection according to the present application is described below from the perspective of a converter device with thyristor protection, where the converter device with thyristor protection may be an electronic device, and the electronic device may be a device such as a mobile phone terminal, a computer terminal, or the like.

The application is applied to a three-phase current converter, namely an inverter, wherein three lines are connected to a load through output ends, namely output, and the other three lines are connected to a public power grid, namely access to the power grid through grid connection. The grid connection mode is connected to a stable power grid so as to obtain continuous power supply; correspondingly, the off-grid mode is only connected to the load, and the energy supply is independent of an external power grid.

The present application will be described in further detail with reference to the accompanying drawings.

Referring to fig. 1, a module connection diagram of a current transformer circuit with thyristor protection provided by an embodiment of the present application includes a parallel-to-off network switching module 1, a rectifying and inverting module 2, and a dc control module 3, and the following details of the modules are described below:

Regarding the on-line and off-line switching module 1: the parallel-to-off network switching module 1 comprises an input end, a grid-connected end and an output end, wherein the input end of the parallel-to-off network switching module is used for receiving the alternating current signal output by the alternating current output end, the grid-connected end is used for being connected with an external public power grid, and the output end of the parallel-to-off network switching module is connected with an external load;

The grid-connected and off-grid switching module 1 further comprises a thyristor and a current limiting element, wherein the thyristor is connected in series at the joint of the input end and the grid-connected end and is used for controlling whether the grid-connected and off-grid switching module is connected to the public power grid or not so as to control the switching of the working condition of the grid-connected and off-grid;

Specifically, in the embodiment of the present application, a circuit breaker is installed at each of the grid-connected end and the output end of the off-grid switching module 1, for disconnecting the output, and a thyristor SCR is connected in series with the grid-connected end, where the thyristor is mainly used for controllable rectification, i.e. a smaller current (or voltage) is used to control a larger current (or voltage), and the circuit breaker is a switching device for cutting off the power supply when the circuit fails, so as to protect the circuit safety. In the circuit provided by the embodiment, the current limiting element is arranged to limit the instantaneous current change flowing through the thyristor, and the current limiting element comprises but is not limited to an inductor, a resistor, a capacitor, a diode, a rheostat, a magnetic resistance and the like.

More specifically, a current transformer is disposed at the output end, and the current transformer is used for detecting the current at the output end to determine whether the current output to the load is abnormal, that is, exceeds a preset current range, in this embodiment, a preset rated current, if the output current sampled by the current transformer is greater than the rated current, the output is controlled to be disconnected, and this process can be implemented by controlling a switching device including, but not limited to, an output contactor, a dc contactor, and the like, which is disposed in the circuit, and in this embodiment, the dc contactor DC Contator is used for control. The circuit provided by the embodiment is also provided with an alternating current lightning protection device connected in parallel at the output end, and the alternating current lightning protection device is used for preventing voltage surge caused by lightning or other reasons from damaging an alternating current system and a connected load.

Regarding the rectification inversion module 2: the rectification inversion module 2 comprises a direct current input end and an alternating current output end, the direct current input end is used for receiving an external direct current signal, and the rectification inversion module 2 is used for rectifying and inverting the direct current signal to obtain an alternating current signal.

Specifically, the rectifying and inverting module 2 is configured to rectify and invert an input dc signal into an ac signal, and is implemented by combining an IGBT unit and a corresponding transformer, where the IGBT includes three-phase bridge arms, the phase difference is 120 °, and each phase bridge arm is a pair of IGBTs, that is, the three-phase bridge arm includes six IGBTs, and the six IGBTs are controlled by external gate signals respectively, so that the six IGBTs are alternately turned on. The upper and lower arms of the bridge arm of the same phase are alternately conductive, and are controlled to be switched on and off by a grid signal to perform current conversion, and each current conversion is performed between the upper and lower arms of the same phase, which is also called longitudinal current conversion. The direction of the current of the converted direct current signal is changed, and the direct current signal is isolated and output based on the electromotive force induction of the transformer, so that an alternating current signal is formed and output.

More specifically, after the combination of the IGBT unit and the transformer is used for rectifying and inverting, and outputting the ac signal, a filtering unit may be further provided to reduce interference and improve the reliability of the ac signal output. In the embodiment of the application, the capacitor is connected in parallel to the three-phase circuit by adopting a triangle connection method, and the three capacitors are connected end to form a closed triangle loop.

Regarding the direct current control module 3: the direct current control module 3 comprises a battery input end, a bus end and a direct current output end, wherein the battery input end is used for receiving an input direct current signal of an external battery;

The bus end is used for receiving an input direct current signal of the external battery so as to balance the voltages of the external battery and the bus, and the direct current output end is used for outputting the voltage of the bus to the direct current input end of the rectifying and inverting module;

the direct current control module 3 further comprises a soft start unit, wherein the soft start unit comprises a first circuit and a second circuit;

Specifically, the DC control module 3 includes a DC breaker DC-Switch, after the DC breaker DC-Switch is turned on, the battery provides a voltage to trigger the subsequent rectification and inversion, but before the rectification and inversion, soft start is required, that is, the battery voltage pre-charges the bus through the first line until the bus voltage is balanced with the battery voltage, and after the contactor AC Contactor disposed on the second line is closed to turn on the second line, in this case, the battery voltage and the bus voltage are kept balanced, and the DC signal is output to the rectification and inversion module 2 through the DC control module 3.

More specifically, the second line is connected with a DC-SPD in parallel, and the DC-SPD is used for preventing voltage surge caused by lightning or other reasons from being applied to a DC system.

On the other hand, a circuit schematic diagram of the inverter circuit with thyristor protection according to an embodiment of the application is provided, and referring to fig. 2, fig. 2 corresponds to the module connection diagram of the inverter circuit with thyristor protection, and specific device connection structures are added for explanation, and the following description is made specifically:

Regarding the rectification inversion module 2: the rectification inversion module 2 comprises IGBT units;

The collectors of the first upper bridge Q1, the second upper bridge Q2 and the third upper bridge Q3 are connected with the positive BUS+ of the BUS, and the emitters of the first lower bridge Q4, the second lower bridge Q5 and the third lower bridge Q6 are connected with the negative BUS-of the BUS;

The collector of the first lower bridge Q4 is connected to the emitter of the first upper bridge Q1, the collector of the second lower bridge Q5 is connected to the emitter of the second upper bridge Q2, and the collector of the third lower bridge Q3 is connected to the emitter of the third upper bridge Q6;

the gates of the first upper bridge Q1, the second upper bridge Q2, the third upper bridge Q3, the first lower bridge Q4, the second lower bridge Q5 and the third lower bridge Q6 respectively receive external gate signals, so as to control the IGBT unit to perform longitudinal commutation according to the gate signals.

Specifically, the external gate signals include six gate signals, namely a first gate signal, a second gate signal, a third gate signal, a fourth gate signal, a fifth gate signal and a sixth gate signal, wherein the first gate signal controls the on and off of the first upper bridge, and the fourth gate signal controls the on and off of the first lower bridge; the second gate signal controls the on-off of the second upper bridge, and the fifth gate signal controls the on-off of the second lower bridge; the third gate signal controls the on-off of the third upper bridge, and the sixth gate signal controls the on-off of the third lower bridge. The external grid signal is a DSP PWM modulation signal, which is a digital signal processing mode, and the stable inversion voltage is modulated by the DSP PWM modulation signal.

More specifically, after rectification by the IGBT unit, the ac signal is obtained by performing isolation output by the transformer unit T1, and the transformer unit is described in detail below:

The transformation unit T1 comprises a first winding, a second winding and a third winding;

the first end of the primary side of the first winding is connected with the emitter of the first upper bridge Q1, and the second end of the primary side of the first winding is connected with the collector of the third lower bridge Q6;

Specifically, a section with a phase of 0 ° to 60 ° is exemplified, and there are a first gate signal, a fifth gate signal, and a sixth gate signal, that is, Q1, Q5, and Q6 in the IGBT unit are turned on, and Q2, Q3, and Q4 are turned off, a direct current signal is output to the BUS-via Q1, the first winding, and Q6, a direct current signal is also output to the BUS-via Q1, the second winding, and Q5, and in addition, a direct current signal is also output to the BUS-via Q1, the second winding, the third winding, and Q6, so that two signals having different current directions are formed at the secondary windings of the first winding, the second winding, and the third winding, thereby isolating the three-phase alternating current signal output in the section.

More specifically, in the phase adjustment period of 60 ° to 120 °, the fifth gate signal is adjusted to the second gate signal, and Q1, Q2, and Q6 are turned on, and Q3, Q4, and Q5 are turned off, in which case the dc signal is commutated from Q5 to Q2, which is referred to as longitudinal commutation, that is, alternating conduction between the upper and lower arms of the same phase.

Further, after the combined rectification and inversion output of the IGBT unit and the transformer unit T1, an LC filter unit is further provided to ensure stability and reliability of the ac signal output to the parallel-to-off network switching module 1, which is described in detail below:

The LC filter unit comprises an alternating current filter capacitor AC-C1, a first inductor L1, a second inductor L2 and a third inductor L3;

The alternating current filter capacitor AC-C1 comprises three capacitors which are connected in parallel at the connection part of the second end of the secondary side of the first winding and the input end, the connection part of the second end of the secondary side of the second winding and the input end and the connection part of the second end of the secondary side of the third winding and the input end in a triangle connection way;

The first inductor L1 is connected in series between the second end of the secondary side of the first winding and the input end, the second inductor L2 is connected in series between the second end of the secondary side of the second winding and the input end, and the third inductor L3 is connected in series between the second end of the secondary side of the third winding and the input end.

Specifically, the transforming unit T1 includes three windings, through which three phase AC signals are output respectively, and for convenience of description, the three windings are defined as a first phase circuit a, a second phase circuit B and a third phase circuit C, and the AC filter capacitor AC-C1 is formed into a triangle by connecting the three capacitors end to end, so that the method is called a triangle connection method, and the three capacitors are respectively connected in parallel to the A, B, C three phase circuits, so that harmonics can be isolated outside the system, and the circulation in the capacitors is limited, thereby protecting the power grid system; A. the B, C three-phase circuit is also connected in series with an inductor which is helpful for reducing current ripple and smoothing output current, thereby ensuring stable output of the inverted signal.

More specifically, in order to improve the reliability of the current transformer, the ac signal after passing through the LC filter unit may be further sampled to detect the inverter current, and a detection device such as a current transformer may be provided in this process. On the other hand, the current transformer can judge the phase through detecting the inversion current, if the inversion current is detected to be abnormal, the output contactor is controlled to be disconnected, so that abnormal inversion current is prevented from being output to a load, and damage to the load is avoided.

More specifically, the filtered alternating current signal is controlled to be switched on and off by the thyristor SCR, the thyristor SCR enters a grid-connected state when being switched on, the signal is output to a public power grid through the current limiting element and the thyristor SCR, and a power grid breaker AC2-MCB is further included between the current limiting element and the thyristor SCR. While the SCR is turned off and is output to the load via the output terminal and the output circuit breakers AC1-MCB on the output terminal, the various embodiments of the current limiting element can be referred to above, the present application is illustrated by way of example with inductance for convenience of description, and the following description is made in detail:

the current limiting element is a fourth inductor L4, a fifth inductor L5 and a sixth inductor L6;

The fourth inductor L4 is connected in series between the first inductor L1 and the thyristor SCR, the fifth inductor L5 is connected in series between the second inductor L2 and the thyristor SCR, and the sixth inductor L6 is connected in series between the third inductor L3 and the thyristor SCR.

Specifically, when the thyristor is used for controlling the inside of the converter and is separated from a grid switch, the thyristor enters a grid connection mode when being closed, otherwise, the thyristor is separated from the grid, a current peak can be generated when the thyristor is separated from the grid, and the current peak is generated when the thyristor is converted from the grid, and through the combination of the inductor, electromotive force can be generated by the inductor to resist current change, so that the thyristor is protected from being damaged.

More specifically, the output is divided into two paths, one path is grid-connected output, the other path is load output, and an AC lightning protection device AC-SPD is connected in parallel before the load output, namely before the output end, so as to protect the connected load from high transient overvoltage generated by lightning stroke.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus/network device and method may be implemented in other manners. For example, the apparatus/network device embodiments described above are merely illustrative, e.g., the division of modules or elements is merely a logical functional division, and there may be additional divisions when actually implemented, e.g., multiple elements or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.

Claims

1. An inverter circuit with thyristor protection, which is characterized in that: the system comprises a parallel-off-grid switching module and a rectification inversion module;

2. The thyristor-protected inverter circuit of claim 1, wherein: the system also comprises a direct current control module;

3. The thyristor-protected inverter circuit of claim 2, wherein: the direct current control module further comprises a soft start unit, wherein the soft start unit comprises a first circuit and a second circuit;

4. A thyristor-protected inverter circuit according to claim 3, wherein: the rectification inversion module comprises an IGBT unit;

5. The thyristor-protected inverter circuit of claim 4, wherein: the rectification inversion module further comprises a transformation unit, wherein the transformation unit comprises a first winding, a second winding and a third winding;

6. The thyristor-protected inverter circuit of claim 5, wherein: the rectification inversion module further comprises an LC filter unit, wherein the LC filter unit comprises an alternating current filter capacitor, a first inductor, a second inductor and a third inductor;

7. The thyristor-protected inverter circuit of claim 6, wherein: the current limiting element is a fourth inductor, a fifth inductor and a sixth inductor;

8. A current transformer with thyristor protection is characterized in that: an inverter circuit with thyristor protection as claimed in any one of claims 1 to 7.