Micro inverter protection circuit and micro inverter topology circuit system

Abstract

Provided are a micro inverter protection circuit and a micro inverter topology circuit system. The protection circuit comprises: successively connected to each other, a current sampling module, a hardware conditioning module and a blocking module; the current sampling module collects a first current signal in a bridge arm of a secondary-side bridge arm circuit where bidirectional switch transistors are located, the secondary-side bridge arm circuit comprising a plurality of bidirectional switch transistors; the hardware conditioning module, into which the first current signal and a preset reference current signal are input, outputs an overcurrent indication signal of the first current signal; the blocking module, into which the overcurrent indication signal and a grid polarity signal are input, outputs a blocking control signal of the bidirectional switch transistors, so as to control, by means of a secondary-side drive circuit, the plurality of bidirectional switch transistors in the secondary-side bridge arm circuit to be blocked. Therefore, when there is an overcurrent in the secondary-side bridge arm circuit, the present invention can promptly and accurately adjust the operating states of the bidirectional switch transistors, thus reliably protecting the switch transistors against damage.

Description

Microinverter protection circuit and microinverter topology circuit system

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on August 31, 2023, with application number 202311124826.4 and invention name “Micro inverter protection circuit and micro inverter topology circuit system”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the field of circuit technology, and in particular to a micro-inverter protection circuit and a micro-inverter topology circuit system. Background Art

[0003] The microinverter topology circuit includes a primary bridge arm circuit, a high-voltage inverter, and a secondary bridge arm circuit. The primary bridge arm circuit connects to the photovoltaic panels, while the secondary bridge arm circuit connects to the grid. The secondary bridge arm circuit includes multiple bidirectional switches, which need to switch between on and off states according to the polarity of the grid voltage. Currently, whether using software or hardware switching, switching states experience a certain delay. If the grid voltage changes polarity at a significant peak, the bidirectional switch state may not be adjusted in time due to the delay, potentially causing a short circuit in the bridge arm where the bidirectional switch resides. This can cause a sharp increase in the current in the bidirectional switch, potentially damaging the switch.

[0004] Summary of the Invention

[0005] In view of this, an object of the present invention is to provide a micro-inverter protection circuit and a micro-inverter topology circuit system, so as to protect the switch tube from being damaged when an overcurrent problem occurs in the secondary bridge arm circuit.

[0006] In a first aspect, an embodiment of the present invention provides a micro-inverter protection circuit, which includes a current sampling module, a hardware conditioning module and a wave-encapsulation module connected in sequence; the current sampling module is arranged on the secondary bridge arm circuit of the micro-inverter topology circuit; the wave-encapsulation module is connected to the secondary side drive circuit of the secondary bridge arm circuit; the current sampling module is used to: collect a first current signal on the bridge arm where the bidirectional switch tube in the secondary bridge arm circuit is located; the secondary bridge arm circuit includes multiple bidirectional switch tubes; the hardware conditioning module is used to: input the first current signal and a preset reference current signal, and output an overcurrent indication signal of the first current signal; wherein the overcurrent indication signal is used to: indicate whether the first current signal is overcurrent; the wave-encapsulation module is used to: input the overcurrent indication signal and the polarity signal of the power grid, and output a blocking control signal of the bidirectional switch tube, so as to control the blocking of multiple bidirectional switch tubes in the secondary bridge arm circuit through the secondary side drive circuit; wherein the blocking control signal indicates that: the multiple bidirectional switch tubes have a preset blocking order.

[0007] The secondary bridge arm circuit includes: a bidirectional switch bridge arm and a capacitor bridge arm; a plurality of bidirectional switch tubes are connected in series on the bidirectional switch bridge arm; and a current sampling module is provided on the main power loop of the bidirectional switch bridge arm.

[0008] The current sampling module includes: a sampling resistor connected in series to the main power circuit, and the voltage across the sampling resistor and the resistance value of the sampling resistor indicate the first current signal.

[0009] The above-mentioned current sampling module includes: a current transformer; the output current of the current transformer and the number of turns of the coil of the current transformer indicate a first current signal.

[0010] The hardware conditioning module is specifically configured to: input a first current signal and a preset reference current signal, and output an overcurrent indication signal of the first current signal based on a magnitude relationship between the first current signal and the reference current signal.

[0011] The micro-inverter topology circuit includes a secondary bridge arm circuit and multiple DC side circuits; the DC side circuit includes a primary bridge arm circuit and a micro-inverter; the hardware conditioning module includes multiple comparators; the number of the comparators is determined based on the number of DC side circuits.

[0012] The number of the above-mentioned comparators is equal to the number of DC side circuits; among the multiple comparators, different comparators input different reference current signals, and the secondary side bridge arm circuits corresponding to different comparators are connected to different numbers of DC side circuits; the reference current signal input by the comparator matches the number of DC side circuits connected to the corresponding secondary side bridge arm circuit.

[0013] The number of the above-mentioned comparators is N. For the x-th comparator, the number of DC side circuits of the secondary bridge arm circuit corresponding to the x-th comparator is x; the reference current signal input by the x-th comparator is: the reference current signal corresponding to the number x; wherein N is an integer greater than zero, and x is an integer greater than or equal to zero and less than or equal to N.

[0014] The above-mentioned comparator inputs the first current signal and also inputs the corresponding reference current signal, and outputs an overcurrent indication signal; wherein, when the overcurrent indication signal is a first value, it indicates that the first current signal is not overcurrent; when the overcurrent indication signal is a second value, it indicates that the first current signal is overcurrent; the overcurrent signal output by the above-mentioned hardware conditioning module includes: the overcurrent indication signal output by each comparator.

[0015] The hardware conditioning module further includes a current adjustment unit; the current adjustment unit is used to adjust the signal size of the first current signal and / or the reference current signal.

[0016] The above comparator includes: a hardware comparator, or an analog comparator in a mathematical signal processing chip.

[0017] The above-mentioned wave blocking module is specifically used to: input an overcurrent indication signal and a polarity signal of the power grid, and if the overcurrent indication signal indicates that the first current signal is overcurrent, output a blocking control signal of the bidirectional switch tube based on the polarity signal.

[0018] The above-mentioned wave blocking module is specifically used to: determine the number of DC side circuits connected to the secondary bridge arm circuit, obtain the overcurrent indication signal corresponding to the number of paths from the overcurrent indication signal output by the hardware conditioning module; obtain the polarity signal of the power grid; and output the blocking control signal of the bidirectional switch tube based on the overcurrent indication signal and the polarity signal.

[0019] The above-mentioned secondary bridge arm circuit includes multiple bidirectional switching tubes connected in series in sequence; the wave blocking module is specifically used to: if the overcurrent indication signal indicates that the first current signal is overcurrent and the polarity signal indicates that the voltage of the power grid is positive, output a first blocking control signal; wherein, the first blocking control signal is used to: first control the blocking of the high-frequency tubes in the multiple bidirectional switching tubes, and then control the blocking of the straight-through tubes in the multiple bidirectional switching tubes.

[0020] The secondary bridge arm circuit includes a first bidirectional switch, a second bidirectional switch, a third bidirectional switch, and a fourth bidirectional switch connected in series. The wave blocking module is specifically configured to output a first blocking control signal if the overcurrent indication signal indicates an overcurrent in the first current signal and the polarity signal indicates a positive grid voltage. The first blocking control signal is configured to first control blocking of the first and third bidirectional switches and then control blocking of the second and fourth bidirectional switches. When the grid voltage is positive, the first and third bidirectional switches are high-frequency switches, and the second and fourth bidirectional switches are straight-through switches.

[0021] The secondary bridge arm circuit includes a first bidirectional switch, a second bidirectional switch, a third bidirectional switch, and a fourth bidirectional switch connected in series. The wave blocking module is specifically configured to output a second blocking control signal if the overcurrent indication signal indicates an overcurrent in the first current signal and the polarity signal indicates a negative grid voltage. The second blocking control signal is configured to first control blocking of the second bidirectional switch and the fourth bidirectional switch, and then control blocking of the first bidirectional switch and the third bidirectional switch.

[0022] When the voltage of the power grid is negative, the first bidirectional switch tube and the third bidirectional switch tube are straight-through tubes, and the second bidirectional switch tube and the fourth bidirectional switch tube are high-frequency tubes.

[0023] In a second aspect, an embodiment of the present invention provides a micro-inverter topology circuit system, which includes a micro-inverter topology circuit and a micro-inverter protection circuit as described in any one of claims 1 to 16; the micro-inverter topology circuit includes: a primary bridge arm circuit, a high-voltage converter and a secondary bridge arm circuit.

[0024] The embodiments of the present invention bring the following beneficial effects:

[0025] The micro-inverter protection circuit and micro-inverter topology circuit system include a current sampling module, a hardware conditioning module, and a wave-encapsulation module connected in sequence. The current sampling module is arranged on the secondary bridge arm circuit of the micro-inverter topology circuit. The wave-encapsulation module is connected to the secondary drive circuit of the secondary bridge arm circuit. The current sampling module is used to collect a first current signal on the bridge arm where the bidirectional switch tube in the secondary bridge arm circuit is located. The secondary bridge arm circuit includes multiple bidirectional switch tubes. The hardware conditioning module is used to input the first current signal and a preset reference current signal and output an overcurrent indication signal of the first current signal. The overcurrent indication signal is used to indicate whether the first current signal is overcurrent. The wave-encapsulation module is used to input the overcurrent indication signal and the polarity signal of the power grid and output a blocking control signal for the bidirectional switch tube to control the blocking of the multiple bidirectional switch tubes in the secondary bridge arm circuit through the secondary drive circuit. The blocking control signal indicates that the multiple bidirectional switch tubes have a preset blocking order.

[0026] In this approach, a current sampling module, a hardware conditioning module, and a wave blocking module are connected to the microinverter protection circuit. The current sampling module collects a first current signal and inputs it into the hardware conditioning module to obtain an overcurrent indication signal. The wave blocking module then determines the blocking order of multiple bidirectional switches based on the overcurrent indication signal and the grid polarity signal, and generates and outputs blocking control signals for the bidirectional switches. This approach allows for timely and accurate adjustment of the operating state of the bidirectional switches when an overcurrent problem occurs in the secondary bridge arm circuit, reliably protecting the switches from damage.

[0027] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purposes and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0030] FIG1 is a schematic diagram of a single-stage micro-inverter topology circuit provided by an embodiment of the present invention;

[0031] FIG2 is a schematic diagram of a single-stage dual-circuit micro-inverter topology circuit provided by an embodiment of the present invention;

[0032] FIG3 is a diagram of a grid voltage polarity and a secondary bridge arm circuit transmitting logic circuit provided by an embodiment of the present invention.

[0033] Edit schematic diagram;

[0034] FIG4 is a schematic structural diagram of a micro-inverter protection circuit provided by an embodiment of the present invention;

[0035] FIG5 is a schematic diagram of a micro-inverter protection circuit provided by an embodiment of the present invention;

[0036] FIG6 is a schematic diagram of a bidirectional switch arm current sampling method provided by an embodiment of the present invention;

[0037] FIG7 is a schematic diagram of another bidirectional switch arm current sampling method provided by an embodiment of the present invention;

[0038] FIG8 is a circuit diagram of a hardware conditioning module provided by an embodiment of the present invention;

[0039] FIG9 is a logic flow chart of a wave encapsulation module performing wave encapsulation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0041] A microinverter is a low-power inverter in a photovoltaic power generation system that features maximum power point tracking (MPPT) for a single photovoltaic cell. Microinverters have various topologies. Figure 1 shows a single-stage microinverter topology, which includes a primary bridge arm circuit, a high-frequency transformer, and a secondary bridge arm circuit.

[0042] The primary bridge circuit, which connects to the photovoltaic panels, utilizes an H-bridge circuit. The middle section is a high-frequency transformer, which boosts the voltage and electrically isolates the primary and secondary sides. The secondary bridge circuit, which connects to the grid, includes multiple bidirectional switches, as shown in Figure 1: S5, S6, S7, and S8. S5 and S6 are located in the upper half of the secondary bridge circuit, while S7 and S8 are located in the lower half. Each bidirectional switch is connected in parallel with a diode, and its switching state is determined by the polarity of the grid voltage.

[0043] Specifically, when the grid voltage is greater than zero, S5 in the upper half-bridge arm's bidirectional switch functions as a high-frequency transistor for high-frequency chopping, while S6 is a straight-through transistor. S7 in the lower half-bridge arm's bidirectional switch functions as a high-frequency transistor for high-frequency chopping, while S8 is a straight-through transistor. When the grid voltage is less than zero, S6 in the upper half-bridge arm's bidirectional switch functions as a high-frequency transistor for high-frequency chopping, while S5 is a straight-through transistor. S8 in the lower half-bridge arm's bidirectional switch functions as a high-frequency transistor for high-frequency chopping, while S7 is a straight-through transistor. High-frequency chopping, in other words, generates a rectangular wave by chopping high frequencies.

[0044] In a single-stage microinverter topology, single-stage grid connection can be achieved by controlling the external phase-shift angles of the primary and secondary bridge arms, as well as the internal phase-shift angle of the primary bridge arm. The internal phase-shift angle is the angle by which switch S4 lags behind switch S1, while the external phase-shift angle is the angle by which switch S5 or S8 lags behind switch S1. Controlling these internal and external phase-shift angles enables energy transfer.

[0045] Depending on the number of PV panels connected to the microinverter, microinverters can be divided into one-to-one microinverters, one-to-two microinverters, one-to-four microinverters, and one-to-six microinverters. In the case of multiple PV inputs, refer to the single-stage dual-channel microinverter topology circuit structure in Figure 2. This topology circuit structure adds a group of PV panels to the one-to-two microinverter topology circuit structure in Figure 1, sharing a set of bidirectional switches and capacitor bridge arms for the secondary bridge arm circuit.

[0046] In the micro-inverter topology described above, the multiple bidirectional switches in the secondary bridge arm circuit need to switch their switching states based on the polarity of the grid voltage. In practical implementation, this switching can be accomplished using software or hardware. However, currently, whether software or hardware switching is used, there is a certain delay in switching the switching states. If the grid voltage polarity changes at a significant peak, such as a sudden grid phase shift or a surge applied to the grid-side port, for example, referring to Figure 3, where the grid voltage is a sinusoidal wave, when the grid voltage is less than zero, that is, below the dashed line, the operating state of the multidirectional switches in the secondary bridge arm circuit should be: switches S5 and S7 are in direct conduction, while switches S6 and S8 are in chopped conduction. When the grid voltage is greater than zero, that is, above the dashed line, the operating state of the multidirectional switches in the secondary bridge arm should be: switches S5 and S7 are in chopped conduction, while switches S6 and S8 are in direct conduction.

[0047] If the grid voltage suddenly switches from point A to point B—that is, if the grid voltage suddenly changes polarity at a significant peak—then within interval 1, due to switching delays, the bidirectional switch logic remains unchanged and uses the same logic used when the grid voltage is greater than zero. This means that switches S5 and S7 are chopped at high frequency, while switches S6 and S8 are directly connected. However, within interval 1, the grid voltage has already fallen below zero, and switches S6 and S8 are directly connected. This creates a short-circuit path through the diodes connected in parallel with switches S5 and S7, shorting the bidirectional switch arm in the secondary bridge circuit. This causes a sharp increase in the bidirectional switch current, potentially damaging the bidirectional switch. Currently, transformer current and grid-connected current provide no protection against this situation.

[0048] Based on the above problems, this embodiment provides a micro-inverter protection circuit and a micro-inverter topology circuit system, which can be applied to solar panels, electric vehicles, household appliances, and other related circuit fields.

[0049] To facilitate understanding of this embodiment, a micro-inverter protection circuit disclosed in an embodiment of the present invention is first introduced in detail.

[0050] Figure 4 is a schematic diagram of the structure of a micro-inverter protection circuit disclosed in this embodiment. As shown in Figure 4, the circuit includes a current sampling module, a hardware conditioning module, and a wave blocking module, which are connected in sequence. The current sampling module is located in the secondary bridge arm circuit of the micro-inverter topology circuit and can collect the first current signal of the bridge arm where the bidirectional switch tube in the secondary bridge arm circuit is located.

[0051] It should be noted that the secondary bridge arm circuit may include multiple bidirectional switching transistors and is connected to the power grid. Furthermore, in the microinverter topology circuit, the secondary bridge arm circuit is also connected to a secondary drive circuit. This secondary drive circuit is connected to a wave blocking module in the microinverter protection circuit and can receive a blocking control signal from the wave blocking module to block the bidirectional switching transistors and perform a wave blocking operation.

[0052] The hardware conditioning module, located between the current sampling module and the wave-enclosing module, receives the first current signal collected by the current sampling module and a preset reference current signal, and outputs an overcurrent indication signal corresponding to the first current signal. The overcurrent indication signal and the grid polarity signal are fed into the wave-enclosing module, which then selects the wave-enclosing logic to output a blocking control signal for the bidirectional switch.

[0053] In one specific embodiment, referring to FIG5 , a current sampling module in a microinverter protection circuit is disposed between the capacitor bridge arm and the lower half bridge arm of the secondary bridge arm circuit of the microinverter topology circuit. It collects the current in the bidirectional switch bridge arm of the secondary bridge arm circuit, i.e., a first current signal. The current sampling module is connected to a hardware conditioning module, which adjusts the first current signal and, based on a preset reference current signal, outputs an overcurrent indication signal for the first current signal. This overcurrent indication signal can be used to indicate whether the first current signal is overcurrent.

[0054] The hardware conditioning module is also connected to the wave blocking module, which can input the overcurrent indication signal. It also inputs the grid polarity signal and the number of access paths. The wave blocking module then determines this information, selects the wave blocking logic, and outputs a blocking control signal for the bidirectional switches. This blocking control signal can indicate a preset blocking sequence for multiple bidirectional switches. The wave blocking module is connected to the secondary-side drive circuit and transmits the blocking control signal to the secondary-side drive circuit, which then performs the blocking operation.

[0055] The above-mentioned number of access paths refers to the number of DC-side circuits connected to the secondary bridge arm circuit. The number of access paths can be determined by judging the voltage of the DC-side circuit. After the number of access paths, the grid polarity, and the overcurrent indication signal output by the hardware conditioning module are input into the wave blocking module, the wave blocking module makes a comprehensive judgment on the above information, selects the wave blocking logic, and then outputs the blocking control signal of the bidirectional switch tube corresponding to the wave blocking logic. Among multiple bidirectional switch tubes, some bidirectional switch tubes have different working states, and the blocking order of bidirectional switch tubes in different states is also different. The blocking control signal contains the preset blocking order of multiple bidirectional switch tubes.

[0056] In this approach, a current sampling module, a hardware conditioning module, and a wave blocking module are connected to the microinverter protection circuit. The current sampling module collects a first current signal and inputs it into the hardware conditioning module to obtain an overcurrent indication signal. The wave blocking module then determines the blocking order of multiple bidirectional switches based on the overcurrent indication signal and the grid polarity signal, and generates and outputs blocking control signals for the bidirectional switches. This approach allows for timely and accurate adjustment of the operating state of the bidirectional switches when an overcurrent problem occurs in the secondary bridge arm circuit, reliably protecting the switches from damage.

[0057] In a specific implementation, the secondary bridge arm circuit includes: a bidirectional switch bridge arm and a capacitor bridge arm; on the bidirectional switch bridge arm, multiple bidirectional switch tubes are connected in series; and the current sampling module is arranged on the main power circuit of the bidirectional switch bridge arm.

[0058] For example, referring to Figure 5, the secondary bridge arm circuit includes a bidirectional switch bridge arm and a capacitor bridge arm. In the bidirectional switch bridge arm, bidirectional switches S5 and S6, and bidirectional switches S7 and S8 are connected in series, and capacitors C1 and C2 are connected to the capacitor bridge arm. It should be noted that the current sampling module is set at any position on the main power circuit of the bidirectional switch bridge arm, and it only needs to be able to collect the current in the bidirectional switch bridge arm. The main power circuit is a circuit that can directly complete power transmission and conversion.

[0059] In one embodiment, the current sampling module includes: a sampling resistor connected in series to the main power circuit, wherein the voltage across the sampling resistor and the resistance value of the sampling resistor indicate the first current signal.

[0060] Specifically, the current sampling module may include a sampling resistor, a resistor used to detect current in a circuit. The sampling resistor is connected in series with the main power circuit. The voltage across the sampling resistor and its resistance value can be used to indicate the first current signal. When the current sampling module includes a sampling resistor, the connection diagram of the sampling module on the bidirectional switch bridge arm can be seen in Figure 6 : the top two terminals connect to the main power circuit, and the bottom two terminals connect to the circuit of the hardware conditioning module.

[0061] In another embodiment, the current sampling module includes: a current transformer; an output current of the current transformer and the number of turns of the coil of the current transformer indicate a first current signal.

[0062] The current sampling module can include a current transformer, which can convert high current into low current, allowing the current to be easily measured by the electric energy meter. The output current of the current transformer and the number of turns of the current transformer coil can be used to indicate the first current signal. When the current sampling module includes a current transformer, the connection method of the sampling module to the bidirectional switch bridge arm can be referred to in Figure 7. The two upper terminals are connected to the main power circuit, and the two lower terminals are connected to the circuit of the hardware conditioning module.

[0063] In one embodiment, the hardware conditioning module is specifically configured to: input a first current signal and a preset reference current signal, and output an overcurrent indication signal of the first current signal based on a magnitude relationship between the first current signal and the reference current signal.

[0064] In actual implementation, the hardware conditioning module can input a first current signal and a preset reference current signal. The preset reference current signal can be set by the hardware conditioning module according to the grid voltage in the circuit and the load condition in the circuit, or according to the conditions of the different DC side paths in the access circuit. The preset reference current signal can be used to ensure the safety of circuit elements and circuit devices. Then, based on the magnitude relationship between the first current signal and the reference current signal, an overcurrent indication signal of the first current signal can be output. Specifically, when the parameter value corresponding to the first current signal is greater than the parameter value of the preset reference current signal, that is, when the current on the bridge arm where the bidirectional switch tube in the secondary bridge arm circuit is located is too large, the hardware conditioning module will output an overcurrent indication signal of the first current signal.

[0065] Figure 8 illustrates the circuitry of a hardware conditioning module as an example. In the figure, Isamp represents the first current signal output by the current sampling module and is input to the hardware conditioning module's "-" input terminal. Iref_1, Iref_2, and Iref_n represent preset reference current signals corresponding to different numbers of DC-side circuits and are input to the hardware conditioning module's "+" input terminal. Iocp_1, Iocp_2, and Iocp_n represent overcurrent indication signals corresponding to the first current signals output by the hardware conditioning module for different numbers of DC-side circuits.

[0066] It should be noted that in the above Iref_n and Iocp_n, n represents the number of connected DC-side paths. In actual implementation, the DC-side voltage can be used to determine whether the DC-side component is connected to the circuit.

[0067] In one embodiment, the micro-inverter topology circuit includes a secondary bridge arm circuit and multiple DC side circuits; the DC side circuit includes a primary bridge arm circuit and a micro-inverter; the hardware conditioning module includes multiple comparators; the number of the comparators is determined based on the number of DC side circuits.

[0068] Specifically, the micro-inverter topology circuit includes one secondary bridge arm circuit and multiple DC-side circuits. For example, a one-to-one micro-inverter topology circuit includes one secondary bridge arm circuit and one DC-side circuit, while a one-to-two micro-inverter topology includes one secondary bridge arm circuit and two DC-side circuits. The DC-side circuit includes the primary bridge arm circuit and the micro-inverter. It is understood that the photovoltaic modules in the DC-side circuit can only generate DC power, and the amount is related to the light intensity. Therefore, the micro-inverter can convert DC power into AC power to facilitate power transmission and utilization.

[0069] It should be noted that the above hardware conditioning module includes a plurality of comparators, and the specific number of comparators can be determined according to the number of DC side circuits in the micro-inverter topology circuit.

[0070] In one embodiment, the number of the above-mentioned comparators is equal to the number of DC side circuits; among the multiple comparators, different comparators input different reference current signals, and the secondary side bridge arm circuits corresponding to different comparators are connected to different numbers of DC side circuits; the reference current signal input by the comparator matches the number of DC side circuits connected to the corresponding secondary side bridge arm circuit.

[0071] That is, the number of comparators in the hardware conditioning module is equal to the number of DC-side circuits in the micro-inverter topology circuit. For example, if the number of DC-side circuits in the micro-inverter topology circuit is 2, then the number of comparators in the hardware conditioning module is also 2. Among the above-mentioned multiple comparators, different comparators input different reference current signals. It can be understood that each DC-side circuit has a corresponding comparator, that is, different comparators correspond to different numbers of DC-side circuits connected to the secondary bridge arm circuit. Since the circuit elements in each DC-side circuit may be different, the safety current of each DC-side circuit may be different, so the reference current signal input to the comparator corresponding to each DC-side circuit is different.

[0072] In one embodiment, the number of the above-mentioned comparators is N. For the x-th comparator, the number of DC side circuits of the secondary bridge arm circuit corresponding to the x-th comparator is x; the reference current signal input by the x-th comparator is: the reference current signal corresponding to the number x; wherein N is an integer greater than zero, and x is an integer greater than or equal to zero and less than or equal to N.

[0073] For example, if the number of comparators is N, the xth comparator corresponds to x DC-side circuits connected to the secondary bridge arm circuit. Accordingly, the reference current signal input to the xth comparator is the reference current corresponding to the x-number of DC-side circuits. Here, N is an integer greater than zero, and x is an integer greater than or equal to zero and less than or equal to N.

[0074] In one embodiment, the comparator inputs a first current signal and a corresponding reference current signal, and outputs an overcurrent indication signal; wherein, when the overcurrent indication signal is a first value, it indicates that the first current signal is not overcurrent; when the overcurrent indication signal is a second value, it indicates that the first current signal is overcurrent; the overcurrent signal output by the hardware conditioning module includes: the overcurrent indication signal output by each comparator.

[0075] That is, the comparator can output an overcurrent indication signal by inputting the first current signal and the corresponding reference current signal. The overcurrent indication signal can have multiple parameter values, such as 0 and 1. When the overcurrent indication signal is the first value, it indicates that the first current signal is not overcurrent; when the overcurrent indication signal is the second value, it indicates that the first current signal is overcurrent. Specifically, when the overcurrent indication signal is 1, it indicates that the current signal is not overcurrent; when the overcurrent indication signal is not 0, it indicates that the current signal is overcurrent.

[0076] It should be noted that the above-mentioned hardware conditioning module includes a plurality of comparators. Therefore, the overcurrent signal output by the hardware conditioning module includes the overcurrent signal output by each comparator.

[0077] In this manner, the first current signal and the corresponding reference current signal are input into the corresponding comparator to obtain an overcurrent indication signal, based on which it is possible to accurately and specifically know which circuit of the DC side circuit has an overcurrent problem.

[0078] In one embodiment, the hardware conditioning module further includes a current adjustment unit configured to adjust the magnitude of the first current signal and / or the reference current signal. Specifically, the hardware conditioning module may further include a current adjustment unit configured to reduce or amplify the first current signal, reduce or amplify the reference current signal, or reduce or amplify both the first current signal and the reference current signal. This ensures that the current signal input to the comparator has a reasonable range.

[0079] In one embodiment, the comparator comprises a hardware comparator or an analog comparator in a mathematical signal processing chip. In actual implementation, the comparator can include a hardware comparator or an analog comparator in a mathematical signal processing chip. Regardless of the comparator type, its purpose is to compare two input signals and output a high or low level signal to indicate the relationship between the two.

[0080] In one embodiment, the wave blocking module is specifically configured to: input an overcurrent indication signal and a grid polarity signal; if the overcurrent indication signal indicates that the first current signal is overcurrent, output a blocking control signal for the bidirectional switch tube based on the polarity signal.

[0081] In actual implementation, the overcurrent indication signal and the polarity signal of the power grid can be input into the wave-sealing module, wherein the input overcurrent indication signal can be used to determine whether the first current signal is overcurrent. If the first current signal is overcurrent, then there is a risk of damage to the circuit components in the circuit, and the working state of multiple bidirectional switch tubes needs to be adjusted in time. Since the polarity signal of the power grid will affect the working state of multiple bidirectional switch tubes, the polarity signal of the power grid and the overcurrent indication signal are both input into the wave-sealing module. When the overcurrent indication signal indicates that the first current signal is overcurrent, the wave-sealing module can output a blocking control signal for the bidirectional switch tube according to the polarity signal of the power grid, and block the corresponding switch tube in time according to the blocking control signal to ensure the safety of the circuit components in the circuit.

[0082] In this way, by inputting the overcurrent indication signal and the polarity signal of the power grid into the wave blocking module, a blocking control signal of the bidirectional switch tube can be obtained, which facilitates timely adjustment of the working state of the bidirectional switch tube to protect circuit components from damage.

[0083] In one embodiment, the above-mentioned wave blocking module is specifically used to: determine the number of DC side circuits connected to the secondary bridge arm circuit, obtain the overcurrent indication signal corresponding to the number of paths from the overcurrent indication signal output by the hardware conditioning module; obtain the polarity signal of the power grid; and output the blocking control signal of the bidirectional switch tube based on the overcurrent indication signal and the polarity signal.

[0084] In actual implementation, the wave encapsulation module can also be used to determine the number of DC side circuits connected to the secondary bridge arm circuit. Specifically, the number of DC side circuits connected to the secondary bridge arm circuit can be determined by judging the DC side circuit voltage. In addition, since the comparator in the hardware conditioning module can output the overcurrent indication signal corresponding to each DC side circuit by inputting the first current signal and the corresponding reference current signal. The wave encapsulation module is connected to the hardware conditioning module, and the overcurrent indication signal corresponding to each DC side circuit can be obtained from the overcurrent indication signal output by the hardware conditioning module. The wave encapsulation module can be connected to the power grid circuit to obtain the polarity signal of the power grid. Finally, based on the above-mentioned overcurrent indication signal and polarity signal, the blocking control signal of the bidirectional switch tube is output.

[0085] In this mode, the blocking module determines the number of DC-side circuits connected to the secondary bridge arm circuit. It then inputs the corresponding overcurrent indication signal for each DC-side circuit and, combined with the grid polarity signal, outputs a blocking control signal for the bidirectional switching transistor. The blocking logic is selected based on the specific DC-side circuit conditions of the secondary bridge arm circuits, providing more reliable protection for the bidirectional switching transistors in the secondary bridge arm circuits.

[0086] In one embodiment, the secondary bridge arm circuit includes a plurality of bidirectional switching tubes connected in series in sequence; the wave blocking module is specifically used to: output a first blocking control signal if the overcurrent indication signal indicates that the first current signal is overcurrent and the polarity signal indicates that the voltage of the power grid is positive; wherein the first blocking control signal is used to: first control the blocking of the high-frequency tubes in the plurality of bidirectional switching tubes, and then control the blocking of the straight-through tubes in the plurality of bidirectional switching tubes.

[0087] Specifically, in the secondary bridge arm circuit, multiple bidirectional switching transistors are connected in series. If the overcurrent indication signal indicates an overcurrent in the first current signal and the polarity signal indicates a positive grid voltage, the wave blocking module outputs a first blocking control signal. This first blocking control signal instructs the high-frequency transistors in the multiple bidirectional switching transistors to be blocked first, followed by the through transistors in the multiple bidirectional switching transistors.

[0088] It should be noted that the main power circuit of the secondary bridge arm circuit needs to be switched on and off at a high frequency, and the switch tube that controls the frequent switching of the main power circuit is a high-frequency tube.

[0089] In a specific embodiment, the secondary bridge arm circuit includes a first bidirectional switch tube, a second bidirectional switch tube, a third bidirectional switch tube, and a fourth bidirectional switch tube connected in series in sequence. The wave blocking module is specifically configured to output a first blocking control signal if the overcurrent indication signal indicates that the first current signal is overcurrent and the polarity signal indicates that the voltage of the power grid is positive. The first blocking control signal is configured to first control the blocking of the first and third bidirectional switch tubes and then control the blocking of the second and fourth bidirectional switch tubes. When the voltage of the power grid is positive, the first and third bidirectional switch tubes are high-frequency tubes, and the second and fourth bidirectional switch tubes are straight-through tubes.

[0090] For example, the secondary bridge arm circuit includes a first bidirectional switch tube, a second bidirectional switch tube, a third bidirectional switch tube, and a fourth bidirectional switch tube connected in series, wherein the first bidirectional switch tube and the second bidirectional switch tube are located in the upper half bridge arm, and the third bidirectional switch tube and the fourth bidirectional switch tube are located in the lower half bridge arm. If the overcurrent indication signal input to the wave encapsulation module indicates that the first current signal is overcurrent, and the polarity signal indicates that the voltage of the power grid is positive, the wave encapsulation module outputs a first blocking control signal, which is used to instruct the first bidirectional switch tube and the third bidirectional switch tube to be controlled and blocked first, and then the second bidirectional switch tube and the fourth bidirectional switch tube to be controlled and blocked. It should be noted that when the power grid voltage is positive, the first bidirectional switch tube and the third bidirectional switch tube are high-frequency tubes, and the second bidirectional switch tube and the fourth bidirectional switch tube are straight-through tubes.

[0091] In another specific embodiment, the secondary bridge arm circuit includes a first bidirectional switch tube, a second bidirectional switch tube, a third bidirectional switch tube, and a fourth bidirectional switch tube connected in series in sequence; the wave blocking module is specifically configured to output a second blocking control signal if the overcurrent indication signal indicates that the first current signal is overcurrent and the polarity signal indicates that the grid voltage is negative; the second blocking control signal is configured to first control the blocking of the second and fourth bidirectional switches, and then control the blocking of the first and third bidirectional switches; wherein, when the grid voltage is negative, the first and third bidirectional switches are pass-through switches, and the second and fourth bidirectional switches are high-frequency switches.

[0092] For example, the secondary bridge arm circuit includes a first bidirectional switch tube, a second bidirectional switch tube, a third bidirectional switch tube, and a fourth bidirectional switch tube connected in series, wherein the first bidirectional switch tube and the second bidirectional switch tube are located in the upper half of the bridge arm, and the third bidirectional switch tube and the fourth bidirectional switch tube are located in the lower half of the bridge arm. If the overcurrent indication signal input to the wave encapsulation module indicates that the first current signal is overcurrent, and the polarity signal indicates that the voltage of the power grid is negative, the wave encapsulation module outputs a second blocking control signal, which is used to instruct the second bidirectional switch tube and the fourth bidirectional switch tube to be blocked first, and then the first bidirectional switch tube and the third bidirectional switch tube to be blocked. It should be noted that when the voltage of the power grid is negative, the first bidirectional switch tube and the third bidirectional switch tube are straight-through tubes, and the second bidirectional switch tube and the fourth bidirectional switch tube are high-frequency tubes.

[0093] In this mode, after selecting the blocking logic, the blocking module outputs a blocking control signal containing blocking information for multiple bidirectional switches. This signal is sent to the secondary-side driver circuit, which then performs blocking. The blocking sequence varies for different bidirectional switches, blocking the high-frequency switch first and then the pass-through switch after a delay. This approach protects the bidirectional switches from damage when overcurrent conditions arise from a short circuit caused by a sudden change in grid voltage polarity.

[0094] For easier understanding, please refer to FIG9 , which is a logic flow chart of the operation of the wave encapsulation module.

[0095] Step S902: Start;

[0096] Step S904: Obtain the number of connected circuits x, overcurrent signals Iocp_1, Iocp_2, ..., Iocp_n, and the grid voltage Vg. Further, execute step S906. Specifically, the wave encapsulation module first obtains the number of circuits x currently connected to the DC side circuit, the overcurrent signals Iocp_1, Iocp_2, ..., Iocp_n corresponding to multiple DC side circuits, and the grid voltage Vg.

[0097] Step S906: Obtain the number of connected circuits x, overcurrent signals Iocp_1, Iocp_2, ..., Iocp_n, and the polarity of the grid voltage Vg. Further, execute step S908. Specifically, after the wave encapsulation module obtains the number of connected DC side circuits x, the overcurrent signals Iocp_1, Iocp_2, ..., Iocp_n corresponding to multiple DC side circuits, and the grid voltage Vg, it also needs to obtain the polarity of the grid voltage.

[0098] Step S908: Determine whether Iocp_x corresponding to the currently connected path is equal to 0. If so, execute step S910; if not, execute step S918. The overcurrent signal Iocp_x includes two parameter values, 0 and 1. If Iocp_x is 0, it indicates that an overcurrent condition exists in the DC side circuit of the currently connected path x. If Iocp_x is 1, it indicates that an overcurrent condition does not exist in the DC side circuit of the currently connected path x. If Iocp_x is 0, further execute step S910. If Iocp_x is not 0, terminate the process.

[0099] Step S910: Determine whether the grid voltage polarity Vg is greater than 0; if so, execute step S912; if not, execute step S914; when the grid voltage polarity is different, the working states of multiple bidirectional switches are also different. Therefore, when Iocp_x is 0, it is necessary to further determine whether the grid voltage polarity Vg is greater than 0.

[0100] Step S912: First block S5 and S7, then block S6 and S8; then execute step S916; if the grid voltage polarity Vg is greater than 0, then bidirectional switches S5 and S7 are high-frequency switches, and bidirectional switches S6 and S8 are straight-through switches. In this case, bidirectional switches S5 and S7 are blocked first, and then bidirectional switches S6 and S8 are blocked after a delay.

[0101] Step S914: First, S6 and S8 are blocked, followed by S5 and S7. Then, step S916 is executed. If the grid voltage polarity Vg is less than 0, then bidirectional switches S6 and S8 are high-frequency switches, and bidirectional switches S5 and S7 are direct-pass switches. In this case, bidirectional switches S6 and S8 are blocked first, followed by S5 and S7 after a delay.

[0102] Step S916: driving output and performing wave blocking; sending the blocking control signals of the above-mentioned multiple bidirectional switch tubes to the secondary side driving circuit, and the secondary side driving circuit performs wave blocking to achieve protection of the bidirectional switch tubes in the overcurrent circuit.

[0103] Step S918: End.

[0104] Regarding the above-mentioned micro-inverter protection circuit, this embodiment further provides a micro-inverter topology circuit system, which includes a micro-inverter topology circuit and the above-mentioned micro-inverter protection circuit; the micro-inverter topology circuit includes: a primary side bridge arm circuit, a high-voltage inverter and a secondary side bridge arm circuit.

[0105] For example, the micro-inverter topology circuit is shown in Figure 1. The primary bridge arm circuit, that is, the circuit connected to the photovoltaic module, adopts an H-bridge circuit; the middle part is a high-frequency transformer, which can achieve voltage boost and electrically isolate the primary and secondary sides; the secondary bridge arm circuit, that is, the circuit connected to the power grid, includes multiple bidirectional switching tubes, bidirectional switching tubes S5 and bidirectional switching tubes S6 are located in the upper half of the secondary bridge arm circuit, and bidirectional switching tubes S7 and bidirectional switching tubes S8 are located in the lower half of the secondary bridge arm circuit, and each bidirectional switching tube is connected in parallel with a diode.

[0106] For example, the micro-inverter topology circuit may also be as shown in FIG2 , including multiple photovoltaic modules, corresponding to multiple high-frequency transformers, and the secondary bridge arm circuits sharing a set of bidirectional switches and capacitor bridge arms.

[0107] In this way, by adding a protection circuit to the micro-inverter topology circuit, when an overcurrent problem occurs in the secondary bridge arm circuit in the micro-inverter topology circuit, the working state of the bidirectional switch tube can be adjusted promptly and accurately, thereby reliably protecting the switch tube from damage.

[0108] In addition, in the description of the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0109] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0110] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0111] Finally, it should be noted that the above embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above embodiments within the technical scope disclosed by the present invention, or replace some of the technical features therein with equivalents. Such modifications, changes or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A micro inverter protection circuit, characterized in that: The circuit comprises a current sampling module, a hardware conditioning module and a wave-sealing module connected in sequence; The current sampling module is arranged on the secondary bridge arm circuit of the micro-inverter topology circuit; the wave-sealing module is connected to the secondary driving circuit of the secondary bridge arm circuit; The current sampling module is used to collect a first current signal on the bridge arm where the bidirectional switch tube in the secondary bridge arm circuit is located; the secondary bridge arm circuit includes a plurality of bidirectional switch tubes; The hardware conditioning module is used to: input the first current signal and a preset reference current signal, and output an overcurrent indication signal of the first current signal; wherein the overcurrent indication signal is used to: indicate whether the first current signal is overcurrent; The blocking module is used to: input the overcurrent indication signal and the polarity signal of the power grid, and output the blocking control signal of the bidirectional switch tube, so as to control the blocking of multiple bidirectional switch tubes in the secondary bridge arm circuit through the secondary drive circuit; wherein the blocking control signal indicates that: the multiple bidirectional switch tubes have a preset blocking order.

2. The circuit according to claim 1, characterized in that The secondary bridge arm circuit comprises: a bidirectional switch bridge arm and a capacitor bridge arm; on the bidirectional switch bridge arm, a plurality of bidirectional switch tubes are connected in series; The current sampling module is arranged on the main power loop of the bidirectional switch bridge arm.

3. The circuit according to claim 1 or 2, characterized in that: The current sampling module includes: a sampling resistor connected in series on the main power circuit, and the voltage across the sampling resistor and the resistance value of the sampling resistor indicate the first current signal.

4. The circuit according to claim 1 or 2, characterized in that: The current sampling module includes: a current transformer; the output current of the current transformer and the number of turns of the coil of the current transformer indicate the first current signal.

5. The circuit according to claim 1, characterized in that The hardware conditioning module is specifically used for: The first current signal and a preset reference current signal are input, and based on the magnitude relationship between the first current signal and the reference current signal, an overcurrent indication signal of the first current signal is output.

6. The circuit according to claim 1, characterized in that The micro-inverter topology circuit includes a secondary bridge arm circuit and multiple DC side circuits; the DC side circuit includes a primary bridge arm circuit and a micro-inverter; The hardware conditioning module includes a plurality of comparators; the number of the comparators is determined based on the number of paths of the DC side circuit.

7. The circuit according to claim 6, characterized in that The number of the comparators is equal to the number of the DC side circuits; Among the multiple comparators, different comparators input different reference current signals, and the secondary bridge arm circuits corresponding to different comparators are connected to different numbers of DC side circuits; The reference current signal input by the comparator matches the number of paths of the DC side circuit to which the corresponding secondary bridge arm circuit is connected.

8. The circuit according to claim 7, characterized in that The number of the comparators is N, and for the x-th comparator, the number of the DC side circuits of the secondary bridge arm circuit corresponding to the x-th comparator is x; The reference current signal input by the xth comparator is: the reference current signal corresponding to the number x of paths; Wherein, N is an integer greater than zero, and x is an integer greater than or equal to zero and less than or equal to N.

9. The circuit according to claim 6, characterized in that The comparator inputs the first current signal and a corresponding reference current signal, and outputs an overcurrent indication signal; Wherein, when the overcurrent indication signal is a first value, it indicates that the first current signal is not overcurrent; when the overcurrent indication signal is a second value, it indicates that the first current signal is overcurrent; The overcurrent signal output by the hardware conditioning module includes: an overcurrent indication signal output by each of the comparators.

10. The circuit according to claim 6, characterized in that The hardware conditioning module further includes a current adjustment unit; the current adjustment unit is used to adjust the signal size of the first current signal and / or the reference current signal.

11. The circuit according to claim 6, characterized in that The comparator includes: a hardware comparator, or an analog comparator in a mathematical signal processing chip.

12. The circuit according to claim 1, characterized in that The wave-enclosing module is specifically used for: The overcurrent indication signal and the polarity signal of the power grid are input, and if the overcurrent indication signal indicates that the first current signal is overcurrent, a blocking control of the bidirectional switch tube is output based on the polarity signal. Signal.

13. The circuit according to claim 1, characterized in that The wave-enclosing module is specifically used for: Determine the number of DC side circuits connected to the secondary bridge arm circuit, and obtain the overcurrent indication signal corresponding to the number of circuits from the overcurrent indication signal output by the hardware conditioning module; Acquire the polarity signal of the power grid; and output a blocking control signal of the bidirectional switch tube based on the overcurrent indication signal and the polarity signal.

14. The circuit according to claim 13, characterized in that The secondary bridge arm circuit includes a plurality of bidirectional switch tubes connected in series in sequence; the wave-sealing module is specifically used for: If the overcurrent indication signal indicates that the first current signal is overcurrent, and the polarity signal indicates that the voltage of the power grid is positive, a first blocking control signal is output; wherein the first blocking control signal is used to: first control the blocking of the high-frequency tubes in the multiple bidirectional switch tubes, and then control the blocking of the straight-through tubes in the multiple bidirectional switch tubes.

15. The circuit according to claim 13, characterized in that The secondary bridge arm circuit comprises a first bidirectional switch tube, a second bidirectional switch tube, a third bidirectional switch tube and a fourth bidirectional switch tube connected in series in sequence; the wave sealing module is specifically used for: If the overcurrent indication signal indicates that the first current signal is overcurrent, and the polarity signal indicates that the voltage of the power grid is positive, a first blocking control signal is output; the first blocking control signal is used to: first control the blocking of the first bidirectional switch tube and the third bidirectional switch tube, and then control the blocking of the second bidirectional switch tube and the fourth bidirectional switch tube; Wherein, when the voltage of the power grid is positive, the first bidirectional switch tube and the third bidirectional switch tube are high-frequency tubes, and the second bidirectional switch tube and the fourth bidirectional switch tube are straight-through tubes.

16. The circuit according to claim 13, characterized in that The secondary bridge arm circuit comprises a first bidirectional switch tube, a second bidirectional switch tube, a third bidirectional switch tube and a fourth bidirectional switch tube connected in series in sequence; the wave-sealing module is specifically used for: If the overcurrent indication signal indicates that the first current signal is overcurrent, and the polarity signal indicates that the voltage of the power grid is negative, a second blocking control signal is output; the second blocking control signal is used to: first control the blocking of the second bidirectional switch tube and the fourth bidirectional switch tube, and then control the blocking of the first bidirectional switch tube and the third bidirectional switch tube; Wherein, when the voltage of the power grid is a negative value, the first bidirectional switch tube and the third bidirectional switch tube are straight-through tubes, and the second bidirectional switch tube and the fourth bidirectional switch tube are high-frequency tubes.

17. A micro inverter topology circuit system, characterized in that: The system comprises a micro-inverter topology circuit and a micro-inverter protection circuit according to any one of claims 1 to 16; The micro inverter topology circuit comprises: a primary bridge arm circuit, a high voltage frequency converter and a secondary bridge arm circuit.

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