CN115764889A - Photovoltaic optimization device, method and system for automatically and quickly controlling voltage safety - Google Patents

Abstract

The invention discloses a photovoltaic optimization device, a photovoltaic optimization method and a photovoltaic system for automatically and quickly controlling voltage safety, and belongs to the technical field of photovoltaic equipment protection. When the photovoltaic power generation system has an emergency fault, the invention reduces the input voltage of the Mode pin of the ASIC chip in the power optimizer in the system by creating the short-circuit environment of the photovoltaic string circuit, and when the power optimizer judges that the input voltage of the Mode pin is lower than the preset threshold voltage, the ASIC chip controls the power optimizer to enter a safe working Mode, thereby realizing the ultra-fast component level turn-off of the photovoltaic power generation system, ensuring the safety of users, personnel and property, and preventing the fault from expanding, wherein the turn-off time can be less than 0.5S. When the photovoltaic power generation system is installed or operated and maintained, the photovoltaic group string can be in a disconnected state, and at the moment, the alternating current switch of the photovoltaic inverter is turned off to stop sending heartbeat packet communication signals, so that the component-level switching-off of the photovoltaic power generation system is realized, and the personnel safety is ensured.

Description

Photovoltaic optimization device, method and system for automatically and quickly controlling voltage safety

Technical Field

The invention relates to the technical field of photovoltaic equipment protection, in particular to a photovoltaic optimization device, method and system for automatically and quickly controlling voltage safety.

Background

The photovoltaic Power conversion device can solve the problem of output Power mismatch between photovoltaic modules when a plurality of photovoltaic modules are connected in series (photovoltaic string), if each photovoltaic module in the photovoltaic string is provided with a Power optimizer, each photovoltaic module is independent relative to the photovoltaic string, MPPT (Maximum Power Point Tracking, MPPT for short) Tracking is independently carried out, the output Power of the photovoltaic Power conversion device cannot be influenced by other photovoltaic modules, namely, when one or part of the photovoltaic string or the photovoltaic module has the problems of surface shielding, dirt, hot spots and the like, other photovoltaic modules still can output the Maximum Power, and photovoltaic string mismatch and string Power loss caused by the shielding and the like are avoided when the photovoltaic modules are connected in series.

In the prior art relating to voltage safety, overseas companies have completed a patented layout for component level fast turn-off based on watchdog technology, wherein U.S. patent No. US8933321B2, filed by Tigo Energy corporation, discloses a system and method for disconnecting solar panels based on watchdog technology, which includes: a watchdog unit of a local controller coupled between the solar modules and a power bus configured to connect the plurality of solar modules to the inverter. The watchdog unit has: a local controller configured to monitor communications from a central controller remote from the solar modules and determine whether the communications have been interrupted for a period of time exceeding a predetermined number of allowed skips.

However, this scheme is based on a watchdog technique, and has a high requirement on the reliability of communication, and usually, power line carrier communication (PLC) with high reliability is used as a communication method, and in order to prevent the solar module from being disconnected by mistake due to an erroneous operation, it is necessary to disconnect the solar module after no signal is detected for a certain period of time. In the rules published by NEC in 2017, it is required to achieve "component-level shutdown" within 30S after the rapid shutdown device is started, however, since the component-level shutdown cannot be achieved within the above duration, the photovoltaic module can also continuously generate electric energy, short circuit and arc faults cannot be eliminated, the fire fault is seriously expanded, and irreversible damage and risks are caused to people and property, and therefore a faster component-level shutdown mode is required.

Disclosure of Invention

In order to solve the technical problems, the invention provides a photovoltaic optimization device, a method and a system for automatically and quickly controlling voltage safety, so as to realize quick turn-off of a component level and ensure the use safety of a photovoltaic power generation system.

In order to achieve the purpose, the invention adopts the following technical scheme:

the photovoltaic optimization device is configured in a photovoltaic power generation system, the photovoltaic power generation system comprises a plurality of photovoltaic string strings connected to a direct current bus of a photovoltaic inverter, the photovoltaic string is formed by connecting a plurality of photovoltaic modules in series, each photovoltaic module comprises a photovoltaic power generation unit and a power optimizer for connecting the photovoltaic power generation unit, the photovoltaic optimization device comprises the power optimizer configured on the output side of the photovoltaic power generation unit and a direct current bypass circuit configured on the output side of the photovoltaic string, and the output ends of the plurality of power optimizers are connected in series to serve as the output end of the photovoltaic string; the direct-current bypass circuit comprises a safety bypass controller, a first auxiliary power supply and a third switch, the third switch is connected between a positive input end and a negative input end of a direct-current end of the photovoltaic inverter, an electric input end of the first auxiliary power supply is connected with an alternating-current end of the photovoltaic inverter, and an electric output end of the first auxiliary power supply is connected with the third switch to supply power to the third switch;

the power optimizer comprises a low-voltage protection and safety regulation and repair circuit, when an ASIC chip in the power optimizer detects the input voltage of a MODE pin, namely the output voltage of the low-voltage protection and safety regulation and repair circuit, and is lower than a preset threshold voltage, the power optimizer is controlled to be switched to or maintained in a safety working MODE if the photovoltaic power generation system is judged to have a short-circuit fault;

a safety adjustment and repair control module in the low-voltage protection and safety adjustment and repair circuit obtains electricity from the photovoltaic power generation unit through a second auxiliary power supply to obtain working voltage, the safety adjustment and repair control module is used for detecting whether heartbeat packet communication signals generated by the safety bypass controller are normal or not, if so, an adjustment and repair instruction is generated to control to disconnect the adjustment and repair switch piece and maintain the adjustment and repair switch piece in a disconnected state until the heartbeat packet communication signals are judged to be abnormal, and the adjustment and repair switch piece is in a disconnected state; and if the heartbeat packet communication signal is abnormal, stopping generating a trimming instruction to control the trimming switch to be disconnected, keeping the trimming switch in a closed state, and keeping the trimming switch in the closed state until the heartbeat packet communication signal is judged to be normal.

Preferably, when a fire hazard emergency fault occurs to a user of a building or a house in which the photovoltaic power generation system is installed, the user turns off a grid-connected switch of a grid-connected point of the photovoltaic inverter or a household-to-household switch of the house and a power grid, the normally-closed third switch which takes power from an alternating-current end of the photovoltaic inverter through the first auxiliary power supply is closed due to power loss of the first auxiliary power supply, a circuit of each photovoltaic string in the photovoltaic power generation system is short-circuited, when the ASIC chip in the power optimizer detects an input voltage of a MODE pin, that is, an output voltage of the low-voltage protection and safety regulation and repair circuit, and is lower than a preset threshold voltage, the circuit of each photovoltaic string in the photovoltaic power generation system is determined to be in a short-circuited state, the power optimizer is controlled to be switched to or maintained in a safety working MODE, the power optimizer stops outputting power and an output working voltage at this time, and the power optimizer outputs a 0V safety voltage at this time; after the emergency fault is eliminated, after the user closes the grid-connected switch or the house-to-house switch of the house and the power grid again, the normally closed third switch which gets electricity from the alternating current end of the photovoltaic inverter through the first auxiliary power supply is disconnected due to the restoration of the power supply of the first auxiliary power supply, the short circuit state of the circuit of each photovoltaic group string of the photovoltaic power generation system is relieved, meanwhile, the safety bypass controller restores to send the heartbeat packet communication signal due to the restoration of the electricity, after the safety adjustment and repair control module detects that the heartbeat packet communication signal generated by the safety bypass controller is normal, an adjustment and repair instruction is generated to control and maintain the adjustment and repair switch element to be in the disconnected state, the ASIC chip detects the input voltage of a MODE pin, namely the output voltage of the low-voltage protection and safety adjustment and repair circuit, and when the output voltage is higher than a preset threshold voltage, the ASIC chip controls the power optimizer to restore to the MPPT working MODE, and the power optimizer restores the output working voltage at the moment.

Preferably, when the photovoltaic power generation system is installed or maintained, the photovoltaic string is not connected or disconnected at this time, a user turns off or does not close a grid-connected switch of a grid-connected point of the photovoltaic inverter, the safety bypass controller stops sending the heartbeat packet communication signal because power supply is stopped, the safety adjustment and repair control module does not detect or detects that the heartbeat packet communication signal is abnormal in the safety bypass controller, the adjustment and repair switching element is in an on state because the adjustment and repair instruction is not received, a MODE pin is conducted with the ground at this time, and when the ASIC chip in the power optimizer detects that the input voltage of a MODE pin, that is, the output voltage of the low-voltage protection and safety adjustment and repair circuit is lower than a preset threshold voltage, the power optimizer is controlled to be switched to or maintained in a safety working MODE, and at this time, the power optimizer stops outputting power and outputs a safety voltage of 0V; after the installation or operation and maintenance of the photovoltaic power generation system is completed, a user closes the grid-connected switch or the house-to-house switch of the house and the power grid again, the normally-closed third switch which gets electricity from the alternating current end of the photovoltaic inverter through the first auxiliary power supply is disconnected due to the restoration of the power supply of the first auxiliary power supply, the safety bypass controller resends the heartbeat package communication signal due to the restoration of the electricity, the safety adjustment and repair control module generates an adjustment and repair instruction to control and maintain the adjustment and repair switch part in a disconnected state after detecting that the heartbeat package communication signal generated by the safety bypass controller is normal, the ASIC chip detects the input voltage of a MODE pin, namely the output voltage of the low-voltage protection and safety adjustment and repair circuit, and controls the power optimizer to recover to an MPPT working MODE when the output voltage is higher than a preset threshold voltage, and then the power optimizer recovers the output power and the output working voltage.

Preferably, the low-voltage protection and safety regulation and repair circuit of the power optimizer comprises a regulation and repair switch, resistors R1 and R2, a diode VD, a capacitor Cx, and the safety regulation and repair control module, wherein the regulation and repair switch is a normally-closed PMOS transistor, a forward body diode is connected between a source and a drain of the PMOS transistor, the source of the regulation and repair switch is grounded, the drain is connected in series with the resistor R1 and then is connected to a Mode pin of the ASIC chip, and a gate is connected to a signal input end of the safety regulation and repair control module; one end of the resistor R2 is connected with a VDD pin of the ASIC chip, and the other end of the resistor R2 is connected with a drain electrode of the PMOS tube and is grounded after being connected with the capacitor Cx; the anode of the diode VD is connected with the drain electrode of the PMOS tube, and the cathode of the diode VD is connected with the V0 pin of the chip;

the safety adjustment and repair control module obtains electricity from the photovoltaic power generation unit through the second auxiliary power supply to obtain working voltage, the safety adjustment and repair control module is used for detecting whether the heartbeat packet communication signal generated by the safety bypass controller is normal or not, and if the heartbeat packet communication signal is normal, an adjustment and repair instruction is generated to control the adjustment and repair switching piece to be disconnected and maintain the adjustment and repair switching piece in a disconnected state until the heartbeat packet communication signal is judged to be abnormal; and if the heartbeat packet communication signal generated by the safety bypass controller is not detected or the signal abnormity is detected, stopping generating a trimming instruction to control the trimming switch piece to be turned on and off, wherein the trimming switch piece is in a turned-on state.

Preferably, the method for switching the power optimizer to which the ASIC chip controls to the safe operating mode includes:

when the ASIC chip detects that the input voltage of the Mode pin of the ASIC chip is lower than the threshold voltage, the ASIC chip drives a first switch in the power optimizer to be turned off and drives a second switch to be turned on so as to control the photovoltaic power generation unit accessed by the power optimizer to stop outputting the photovoltaic power and the working voltage, and at the moment, the power optimizer outputs 0V safe voltage, so that the running state of the power optimizer is switched to a safe working Mode;

the power optimizer comprises the ASIC chip, the first switch, the second switch, an input capacitor Cin, an output capacitor Cout and an energy storage inductor L, wherein the first switch and the second switch are MOS (metal oxide semiconductor) tubes, and the grid electrode of the first switch is connected with the HD-driver pin of the ASIC chip; the grid electrode of the second switch is connected with an LD-driver pin of the ASIC chip; one end of the energy storage inductor L is connected with the source electrode of the first switch, the other end of the energy storage inductor L is connected with one end of the output capacitor Cout, and the other end of the output capacitor Cout is connected with the source electrode of the second switch; and the input capacitor Cin is connected in parallel between the positive output end and the negative output end of the photovoltaic power generation unit.

Preferably, the ASIC chip internally includes a maximum power tracking circuit, a reference voltage generating circuit, a mode control circuit, a drive control circuit, and an internal chip power supply circuit;

the maximum power tracking circuit comprises a voltage and current detection unit, a multiplier and a maximum power tracking processing unit, wherein the voltage and current detection unit is used for collecting the output voltage and the output current of the accessed photovoltaic power generation unit;

the multiplier is used for multiplying the output voltage acquired by the voltage and current detection unit and the output current to obtain the output power of the photovoltaic power generation unit;

the input end of the maximum power tracking processing unit is connected with the output end of the multiplier and is used for tracking the maximum power point of the photovoltaic power generation unit;

the reference voltage generating circuit is used for providing reference voltage for determining duty ratio signals for the maximum power tracking circuit and providing reference voltage for mode control for the mode control circuit by using power supply of the chip internal power supply circuit, and when the power optimizer runs in an MPPT working mode, the ASIC chip controls the on-off of the first switch and the second switch according to the duty ratio signals so as to realize maximum power tracking of the accessed photovoltaic power generation unit;

a signal output end of the Mode control circuit is connected with the Mode pin of the ASIC chip, a first signal input end of the low-voltage protection and safety repair circuit at the periphery of the chip is connected with the Mode pin, a second signal input end of the low-voltage protection and safety repair circuit is connected with a VDD pin of the chip, when the input voltage of the Mode pin of the ASIC chip is lower than the preset threshold voltage, the ASIC chip controls the power optimizer to operate in a safety working Mode, and when the input voltage of the Mode pin of the ASIC chip is higher than the preset threshold voltage, the ASIC chip recovers the power optimizer to operate in an MPPT working Mode;

the drive control circuit comprises a logic control unit, a first drive unit and a second drive unit, wherein a first input end of the logic control unit is connected with a signal output end of the mode control circuit, a second input end of the logic control unit is connected with a signal output end of the maximum power tracking unit, a first output end and a second output end of the logic control unit are respectively connected with signal input ends of the first drive unit and the second drive unit, a signal output end of the first drive unit and a signal output end of the second drive unit are respectively connected with an HD-driver pin and an LD-driver pin of the ASIC chip, and the drive control circuit is used for controlling the on-off of the first switch and the second switch according to preset control logic.

The invention also provides a method for automatically and quickly controlling voltage safety applied to a photovoltaic power generation system, which is realized by the photovoltaic optimization device, wherein the photovoltaic power generation system comprises a plurality of photovoltaic string strings connected to a direct current bus of a photovoltaic inverter, each photovoltaic string is formed by connecting a plurality of photovoltaic components in series, each photovoltaic component comprises a photovoltaic power generation unit and a power optimizer for accessing the photovoltaic power generation unit, the photovoltaic optimization device comprises the power optimizer arranged on the output side of the photovoltaic power generation unit and a direct current bypass circuit arranged on the output side of the photovoltaic string, and the output ends of the plurality of power optimizers are connected in series to serve as the output end of the photovoltaic string; the direct current bypass circuit comprises a safety bypass controller, a first auxiliary power supply and a third switch, the third switch is connected between a positive input end and a negative input end of a direct current end of the photovoltaic inverter, an electric input end of the first auxiliary power supply is connected with an alternating current end of the photovoltaic inverter, and an electric output end of the first auxiliary power supply is connected with the third switch to supply power to the third switch;

the power optimizer comprises an ASIC chip and a low-voltage protection and safety adjustment circuit;

the method for automatically and quickly controlling the voltage safety comprises the following steps:

when the ASIC chip in the power optimizer detects that the output voltage of the low-voltage protection and safety regulation and repair circuit is lower than a threshold voltage, the power optimizer is controlled to be switched to or maintained in a safety working mode;

and a safety adjustment and repair control module in the low-voltage protection and safety adjustment and repair circuit obtains electricity from the photovoltaic power generation unit through a second auxiliary power supply to obtain working voltage, the safety adjustment and repair control module is used for detecting whether heartbeat packet communication signals generated by the safety bypass controller are normal or not, if the heartbeat packet communication signals are normal, an adjustment and repair instruction is generated to control the adjustment and repair switching piece to be disconnected and maintain the disconnection state until the heartbeat packet communication signals are judged to be abnormal, when the adjustment and repair switching piece is in the disconnection state, the output end voltage of the low-voltage protection and safety adjustment and repair circuit is higher than the threshold voltage, the ASIC chip judges that short-circuit faults are relieved, controls the power optimizer to recover the MPPT working mode, and at the moment, the power optimizer recovers output power and output working voltage.

Preferably, the method for judging the short-circuit fault of the photovoltaic power generation system comprises the following steps:

and the grid-connected switch of the grid-connected point of the photovoltaic inverter or the household switch of the house and the power grid is turned off, the normally closed third switch which gets electricity from the alternating current end of the photovoltaic inverter through the first auxiliary power supply is closed due to the power loss of the first auxiliary power supply, the third switch is connected between the positive input end and the negative input end of the direct current side of the photovoltaic inverter, and after the third switch is closed, each photovoltaic group string connected to the direct current bus of the photovoltaic inverter is short-circuited.

Preferably, the method for the power optimizer to control to enter the safe operation mode includes:

when the ASIC chip detects that the input voltage of the Mode pin of the ASIC chip is lower than the threshold voltage, the first switch in the power optimizer is driven to be switched off and the second switch is driven to be switched on, so that the photovoltaic power generation unit connected to the power optimizer is controlled to stop outputting photovoltaic power and voltage, and the running state of the power optimizer is switched to or maintained in a safe working Mode.

Preferably, when the power optimizer is switched into a safe working mode for a set duration, the ASIC chip controls the power optimizer to enter a non-working mode, in the non-working mode, both the first switch and the second switch in the power optimizer are in an off state, at this time, the power optimizer stops outputting power and working voltage, and at this time, the power optimizer outputs a 0V safe voltage.

Preferably, the method for the power optimizer to control to enter the MPPT operating mode includes:

the grid-connected switch is turned on, after the photovoltaic inverter recovers grid connection, the first auxiliary power supply of the direct current bypass circuit recovers power supply, the safety bypass controller controls the third switch to be switched off after power is supplied, and meanwhile, the safety bypass controller recovers sending of the heartbeat packet communication signal;

and the safety adjustment and repair control module generates an adjustment and repair instruction to control the adjustment and repair switching piece to be disconnected and maintain the adjustment and repair switching piece in a disconnected state after detecting the heartbeat packet communication signal generated by the safety bypass controller, when the adjustment and repair switching piece is in the disconnected state, the output end voltage of the low-voltage protection and safety adjustment and repair circuit is recovered to be higher than the threshold voltage, the power optimizer is controlled to recover the MPPT working mode, and at the moment, the power optimizer recovers the output power and the output working voltage.

Preferably, the method for releasing the short-circuit fault of the photovoltaic power generation system comprises the following steps:

and after the grid-connected switch of the grid-connected point of the alternating current inverter or the house-in switch of the house and the power grid is closed, the normally closed third switch which gets electricity from the alternating current end of the photovoltaic inverter through the first auxiliary power supply is disconnected due to the recovery of the power supply of the first auxiliary power supply, the third switch is connected between the positive input end and the negative input end of the direct current side of the photovoltaic inverter, and after the third switch is disconnected, the short-circuit fault is removed.

The invention also provides a photovoltaic power generation system, and the photovoltaic power generation system is provided with the photovoltaic optimization device for automatically and quickly controlling the voltage safety.

The invention has the following beneficial effects:

(1) When a user such as a building or a house provided with the photovoltaic power generation system has an emergency fault such as a fire, the power optimizer is switched from the MPPT working mode to the safe working mode or the non-working mode by creating a short-circuit environment of a photovoltaic string circuit in the photovoltaic power generation system, and at the moment, the power optimizer stops outputting power and outputting 0V safe voltage. The component-level turn-off of the photovoltaic power generation system is quickly realized, the time for realizing the component-level turn-off cannot exceed 0.5S, and therefore the risk of realizing the component-level turn-off in the existing scheme 30S can be avoided.

(2) After the fault is relieved, a grid-connected switch is required to be switched on, after a photovoltaic inverter recovers grid connection, an auxiliary power supply of an optical direct current bypass circuit recovers power supply, a safety bypass controller controls a third switch to be switched off, meanwhile, the safety bypass controller recovers to normally send heartbeat packet communication signals, a safety debugging control module is used for generating a debugging command to control a switching part power optimizer to be switched off and repaired to recover from a non-working mode to an MPPT working mode after detecting that the heartbeat packet communication signals generated by the safety bypass controller are normal, and a photovoltaic module recovers to normal power generation and a string to normal working voltage, so that the safety risk caused by the fact that the short-circuit state of a photovoltaic string circuit is relieved and the output voltage and power of the photovoltaic module are recovered by mistake after a line of the photovoltaic string is burnt due to the fire fault of a building can be well avoided; meanwhile, when the photovoltaic system is not installed and operation and maintenance are fashionable, the photovoltaic string connection or disconnection can be completed, the power optimizer can be switched from the MPPT working mode to the safe working mode or the non-working mode by disconnecting the heartbeat packet communication signal sent by the safe bypass controller, and the power optimizer stops outputting power and safe voltage of 0V at the moment, so that safe construction and operation and maintenance of the photovoltaic system are guaranteed.

(3) The invention avoids the high requirement that the assembly-level quick turn-off needs to be continuous and reliable for acquiring the heartbeat signal by using the watchdog technology in the prior art, can realize the quick turn-off of the assembly level without depending on any communication system, improves the reliability, and can ensure that no direct current high voltage exists in the system and the personal safety of field personnel under emergency conditions such as fire fighting and extinguishment.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly described below. It is obvious that the drawings described below are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

Fig. 1 is a schematic structural diagram of a photovoltaic power generation system with a photovoltaic optimization device for automatically and rapidly controlling voltage safety according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the internal structure of the power optimizer;

FIG. 3 is a schematic diagram of an internal circuit structure of an ASIC chip;

FIG. 4 is a schematic diagram of the power optimizer operating in the MPPT mode of operation;

FIG. 5 is a schematic diagram of the power optimizer operating in a safe mode of operation;

fig. 6 is a schematic diagram of the power optimizer operating in a non-operating mode.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

Wherein the showings are for the purpose of illustration only and are shown by way of illustration only and not in actual form, and are not to be construed as limiting the present patent; for a better explanation of the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "inner", "outer", etc. are used for indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not indicated or implied that the referred device or element must have a specific orientation, be constructed in a specific orientation and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and are not to be construed as limitations of the present patent, and the specific meanings of the terms may be understood by those skilled in the art according to specific situations.

In the description of the present invention, unless otherwise explicitly specified or limited, the term "connected" or the like, if appearing to indicate a connection relationship between the components, is to be understood broadly, for example, as being fixed or detachable or integral; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or may be connected through one or more other components or may be in an interactive relationship with one another. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art.

The photovoltaic optimization device for automatically and rapidly controlling voltage safety provided by an embodiment of the invention is configured in a photovoltaic power generation system, as shown in fig. 1, the photovoltaic power generation system comprises a plurality of photovoltaic string connected to a direct current bus of a photovoltaic inverter, the photovoltaic string is formed by connecting a plurality of photovoltaic modules in series, each photovoltaic module comprises a photovoltaic power generation unit 5 and a power optimizer 1 for accessing the photovoltaic power generation unit 5, the photovoltaic optimization device comprises the power optimizer 1 configured on the output side of the photovoltaic power generation unit 5 and a direct current bypass circuit configured on the output side of the photovoltaic string, and the output ends of the plurality of power optimizers 1 are connected in series to serve as the output end of the photovoltaic string;

the direct current bypass circuit comprises a safety bypass controller 2, a first auxiliary power supply 3 and a third switch s3, the third switch s3 is connected between a positive input end and a negative input end of a direct current end of the photovoltaic inverter, an electric input end of the first auxiliary power supply 3 is connected with an alternating current end of the photovoltaic inverter, and an electric output end of the first auxiliary power supply 3 is connected with the third switch s3 to supply power for the third switch s3 and the safety bypass controller 2; the safety bypass controller 2 is further configured to send a heartbeat packet communication signal to the power optimizer 1;

the power optimizer 1 comprises a low voltage protection and safety trimming circuit 100 and an ASIC chip 10 shown in fig. 2, wherein the ASIC chip 10 controls the power optimizer 1 to switch to or maintain in a safety operation mode when detecting that the output voltage of the low voltage protection and safety trimming circuit 100 is lower than a threshold voltage;

a safety adjustment and repair control module 104 in the low-voltage protection and safety adjustment and repair circuit 100 obtains electricity from the photovoltaic power generation unit 5 through a second auxiliary power supply 105 to obtain a working voltage, the safety adjustment and repair control module 104 is used for detecting whether a heartbeat packet communication signal sent by the safety bypass controller 2 is normal, and if the heartbeat packet communication signal is normal, an adjustment and repair instruction is generated to control to disconnect a normally-closed adjustment and repair switching element 103 in the low-voltage protection and safety adjustment and repair circuit 100 and maintain the normally-closed adjustment and repair switching element in a disconnected state until the heartbeat packet communication signal is judged to be abnormal, and the adjustment and repair switching element 103 is in a disconnected state; if the heartbeat packet communication signal is abnormal, the generation of the adjusting and repairing instruction is stopped to control the adjustment and repairing switch part 103 to be disconnected, the adjustment and repairing switch part 103 is in a closed state, and the closed state is maintained until the heartbeat packet communication signal is judged to be normal.

When a fire hazard emergency fault occurs to a user of a building or a house in which the photovoltaic power generation system is installed, the user turns off a grid-connected switch of a grid-connected point of the photovoltaic inverter or a house-to-house switch of a house and a power grid, the normally-closed third switch s3 which is used for taking electricity from an alternating current end of the photovoltaic inverter through the first auxiliary power supply 3 is closed due to the loss of electricity of the first auxiliary power supply 3, a circuit of each photovoltaic group string in the photovoltaic power generation system is short-circuited, when the ASIC chip 10 in the power optimizer 1 detects an input voltage of a MODE pin, namely an output voltage of the low-voltage protection and safety regulation and repair circuit 100, and is lower than a preset threshold voltage, the circuit of each photovoltaic group string in the photovoltaic power generation system is determined to be in a short-circuited state, the power optimizer 1 is controlled to be switched to or maintained in a safety working MODE, at the moment, the power optimizer 1 stops outputting power and outputting working voltage, and at the moment, and the power optimizer 1 outputs 0V safety voltage; after the emergency fault is eliminated, after the user closes the grid-connected switch or the household switch of the house and the power grid again, the normally closed third switch s3 which gets electricity from the ac end of the photovoltaic inverter through the first auxiliary power supply 3 is disconnected due to the restoration of power supply of the first auxiliary power supply 3, the short circuit state of the circuit of each photovoltaic group string of the photovoltaic power generation system is released, meanwhile, the safety bypass controller 2 restores to send the heartbeat packet communication signal due to the restoration of power, after the safety tuning control module 104 detects that the heartbeat packet communication signal generated by the safety bypass controller 2 is normal, the tuning instruction is generated to control and maintain the tuning switch 103 in the disconnected state, the ASIC chip 10 detects the input voltage of the MODE pin, that is, the output voltage of the low-voltage protection and safety tuning circuit 100 is higher than the preset threshold voltage, the ASIC chip 10 controls the power optimizer 1 to restore to the MPPT working MODE, and at this time, the power optimizer 1 restores the output power and the output working voltage.

When the photovoltaic power generation system is installed or operated and maintained, at this time, the photovoltaic string is not connected or disconnected, a user turns off or does not close a grid-connected switch of a grid-connected point of the photovoltaic inverter, the safety bypass controller 2 stops sending the heartbeat packet communication signal due to stopping of power supply, the safety debugging control module 104 does not detect or detects that the heartbeat packet communication signal is abnormal in the safety bypass controller 2, the debugging switch element 103 is in an on state due to not receiving the debugging instruction, at this time, a MODE pin is conducted with the ground, and when the ASIC chip 10 in the power optimizer 1 detects an input voltage of a MODE pin, that is, an output voltage of the low-voltage protection and safety debugging circuit 100 is lower than a preset threshold voltage, the power optimizer 1 is controlled to be switched to or maintained in a safety working MODE, at this time, the power optimizer 1 stops outputting power and outputs a safety voltage of 0V; after the installation or operation and maintenance of the photovoltaic power generation system is completed, after the user closes the grid-connected switch or the house-to-house switch of the house and the power grid again, the normally-closed third switch s3 which gets electricity from the ac terminal of the photovoltaic inverter through the first auxiliary power supply 3 is disconnected due to the power restoration of the first auxiliary power supply 3, the security bypass controller 2 retransmits the heartbeat package communication signal due to the electricity restoration, and after the security tuning control module 104 detects that the heartbeat package communication signal generated by the security bypass controller 2 is normal, the security tuning control module generates a tuning instruction to control and maintain the tuning switch element 103 in a disconnected state, the ASIC chip 10 detects the input voltage of the MODE pin, that is, the output voltage of the low-voltage protection and security tuning circuit 100, and when the output voltage is higher than a preset threshold voltage, the ASIC chip 10 controls the power optimizer 1 to be restored to the MPPT working MODE, and at this time, the power optimizer 1 restores the output power and outputs the working voltage.

The principle of controlling the power optimizer 1 to switch to the safe mode or the non-operating mode, or to revert to the MPPT operating mode is as follows:

the power optimizer 1 is connected to a photovoltaic power generation unit 5 to form a photovoltaic module, a plurality of photovoltaic modules are connected in series to form a photovoltaic string 300, an electrical output end of each photovoltaic string 300 is connected to a direct current bus 41 of a photovoltaic inverter 4, when a user turns off a grid-connected switch 6 of a grid-connected point of the ac inverter 4 or a house-in switch of a house and a power grid due to a fault, a normally-closed third switch s3 which gets electricity from an alternating current end of the photovoltaic inverter 4 through a first auxiliary power supply 3 is closed due to the loss of electricity of the first auxiliary power supply 3, short circuit occurs among the photovoltaic string in the photovoltaic power generation system, meanwhile, the safety bypass controller 2 stops sending heartbeat packet communication signals, the safety adjustment control module 104 controls a closed adjustment switch 103 due to failure of normally receiving the heartbeat packet communication signals, and when an input voltage of a Mode pin of an ASIC chip 10 in each power optimizer 1 is pulled down to be lower than a preset threshold voltage, the ASIC chip 10 controls the corresponding power optimizer 1 to switch from an MPPT operation Mode shown in fig. 4 or a non-operation Mode shown in fig. 6;

when the grid-connected switch 6 of the grid-connected point of the ac inverter 4 or the household switch of the house and the power grid is closed by troubleshooting, the normally closed third switch s3 which takes electricity from the ac terminal of the photovoltaic inverter 4 through the first auxiliary power supply 3 is disconnected due to the recovery of the power supply of the first auxiliary power supply 3, the short-circuit environment is relieved, the heartbeat packet communication signal is resent by the security bypass controller 2 when the electricity is recovered, when the security tuning control module 104 detects that the heartbeat packet communication signal generated by the security bypass controller 2 is normal, the tuning instruction is generated to control and maintain the tuning switch 103 in the disconnected state, the ASIC chip 10 controls the corresponding power optimizer 1 to resume the MPPT operation Mode shown in fig. 4 from the security operation Mode or the non-operation Mode after the input voltage of the Mode pin of the ASIC chip 10 is pulled up to reach the preset threshold voltage, and then the power optimizer 1 resumes the output power and the output operation voltage.

The low-voltage protection and safety adjustment and repair circuit 100 of the power optimizer 1 comprises an adjustment and repair switch part 103, resistors R1 and R2, a diode VD, a capacitor Cx, and a safety adjustment and repair control module 104, wherein the adjustment and repair switch part 103 is a normally closed PMOS transistor, a forward body diode is connected between a source and a drain of the PMOS transistor, the source of the adjustment and repair switch part 103 is grounded, the drain is connected to a Mode pin of the ASIC chip 10 after being connected in series with the resistor R1, and a gate is connected to a signal input end of the safety adjustment and repair control module 104; one end of the resistor R2 is connected with a VDD pin of the ASIC chip 10, and the other end of the resistor R2 is connected with a drain electrode of a PMOS tube and is grounded after being connected with the capacitor Cx; the anode of the diode VD is connected with the drain electrode of the PMOS tube, and the cathode of the diode VD is connected with the V0 pin of the chip;

the safety adjustment and repair control module 104 obtains electricity from the photovoltaic power generation unit 5 through the second auxiliary power supply 105 to obtain working voltage, the safety adjustment and repair control module 104 is used for detecting whether heartbeat packet communication signals generated by the safety bypass controller 2 are normal, and if the heartbeat packet communication signals are normal, an adjustment and repair instruction is generated to control the disconnection of the adjustment and repair switching element 103 and maintain the disconnection state of the adjustment and repair switching element until the heartbeat packet communication signals are judged to be abnormal; if the heartbeat packet communication signal generated by the safety bypass controller 2 is not detected or the signal abnormality is detected, the generation of the adjustment and repair instruction is stopped to control the adjustment and repair switch part 103 to be turned on and off, and the adjustment and repair switch part 103 is in a turned-on state.

The method for controlling the power optimizer 1 to switch to the safe working mode by the ASIC chip 10 is as follows:

when the ASIC chip 10 detects that the input voltage of the Mode pin is lower than a preset threshold voltage, the ASIC chip drives the first switch 20 in the power optimizer 1 shown in fig. 2 to turn off and drives the second switch 30 to turn on, so as to control the photovoltaic power generation unit 5 connected to the power optimizer 1 to stop outputting the photovoltaic power and the working voltage, and at this time, the power optimizer 1 outputs a 0V safety voltage, thereby switching the operating state of the power optimizer 1 to the safety operating Mode;

as shown in fig. 2, the power optimizer 1 includes an ASIC chip 10, a first switch 20, a second switch 30, an input capacitor Cin, an output capacitor Cout, and an energy storage inductor L, where the first switch 20 and the second switch 30 are NMOS transistors, a gate of the first switch 20 is connected to an HD-driver pin of the ASIC chip 10, and a gate of the second switch 30 is connected to an LD-driver pin of the ASIC chip 10; one end of the energy storage inductor L is connected to the source of the first switch 20, the other end is connected to one end of the output capacitor Cout, and the other end of the output capacitor Cout is connected to the source of the second switch 30; the input capacitor Cin is connected in parallel between the positive output end and the negative output end of the photovoltaic power generation unit 5.

As shown in fig. 3 and 2, the ASIC chip 10 internally includes a maximum power tracking circuit, a reference voltage generation circuit, a mode control circuit, a drive control circuit, a communication interface circuit, and an internal chip power supply circuit,

the maximum power tracking circuit comprises a voltage and current detection unit, a multiplier and a maximum power tracking processing unit, wherein the voltage and current detection unit is used for collecting the output voltage and the output current of the accessed photovoltaic power generation unit 5;

the multiplier is used for multiplying the output voltage and the output current collected by the voltage and current detection unit to obtain the output power of the photovoltaic power generation unit 5;

the input end of the maximum power tracking processing unit is connected with the output end of the multiplier and used for tracking the maximum power point of the photovoltaic power generation unit 5;

the reference voltage generating circuit is used for providing reference voltage for determining duty ratio signals for the maximum power tracking circuit and providing reference voltage for mode control for the mode control circuit by using power supply of the chip internal power supply circuit, and when the power optimizer 1 operates in the MPPT working mode, the ASIC chip 10 controls the on-off of the first switch 20 and the second switch 30 according to the duty ratio signals so as to realize maximum power tracking of the accessed photovoltaic power generation unit 5;

a signal output end of the Mode control circuit is connected with a Mode pin of the ASIC chip 10, a first signal input end 101 of a low-voltage protection and safety trimming circuit 100 on the periphery of the chip is connected with the Mode pin, a second signal input end 102 is connected with a VDD pin of the chip, when an input voltage of the Mode pin of the ASIC chip 10 is lower than a preset threshold voltage, the ASIC chip 10 controls the power optimizer 1 to operate in a safety working Mode, and when the input voltage of the Mode pin of the ASIC chip 10 reaches the preset threshold voltage, the ASIC chip 10 restores the power optimizer 1 to operate in an MPPT working Mode;

the driving control circuit comprises a logic control unit, a first driving unit and a second driving unit, wherein a first input end of the logic control unit is connected with a signal output end of the mode control circuit, a second input end of the logic control unit is connected with a signal output end of the maximum power tracking unit, a first output end and a second output end of the logic control unit are respectively connected with signal input ends of the first driving unit and the second driving unit, signal output ends of the first driving unit and the second driving unit are respectively connected with an HD-driver pin and an LD-driver pin of the ASIC chip 10, and the driving control circuit is used for controlling the on-off of the first switch 20 and the second switch 30 according to preset control logic.

The method for automatically and rapidly controlling voltage safety applied to the photovoltaic power generation system provided by the invention has been explained in detail in the above-mentioned explanation of the principle of automatically and rapidly controlling voltage safety of the photovoltaic optimization device, and is not repeated.

The invention also provides a photovoltaic power generation system, and the photovoltaic optimization device for automatically and quickly controlling the voltage safety is arranged in the photovoltaic power generation system.

It should be understood that the above-described embodiments are merely preferred embodiments of the invention and the technical principles applied thereto. It will be understood by those skilled in the art that various modifications, equivalents, changes, and the like can be made to the present invention. However, such variations are within the scope of the invention as long as they do not depart from the spirit of the invention. In addition, certain terms used in the specification and claims of the present application are not limiting, but are used merely for convenience of description.

Claims (11)

1. A photovoltaic optimization device for automatically and rapidly controlling voltage safety is configured in a photovoltaic power generation system, and is characterized in that the photovoltaic power generation system comprises a plurality of photovoltaic string strings connected to a direct current bus of a photovoltaic inverter, the photovoltaic string is formed by connecting a plurality of photovoltaic modules in series, each photovoltaic module comprises a photovoltaic power generation unit (5) and a power optimizer (1) used for being connected into the photovoltaic power generation unit (5), the photovoltaic optimization device comprises the power optimizer (1) configured on the output side of the photovoltaic power generation unit (5) and a direct current bypass circuit configured on the output side of the photovoltaic string, and the output ends of the plurality of power optimizers (1) are connected in series to serve as the output end of the photovoltaic string;

the direct current bypass circuit comprises a safety bypass controller (2), a first auxiliary power supply (3) and a third switch (s 3), wherein the third switch (s 3) is connected between a positive input end and a negative input end of a direct current end of the photovoltaic inverter, an electric input end of the first auxiliary power supply (3) is connected with an alternating current end of the photovoltaic inverter, and an electric output end of the first auxiliary power supply (3) is connected with the third switch (s 3) to supply power for the third switch (s 3) and the safety bypass controller (2); the safety bypass controller (2) is also used for sending a heartbeat packet communication signal to the power optimizer (1);

the power optimizer (1) comprises an ASIC (application specific integrated circuit) chip (10) and a low-voltage protection and safety regulation circuit (100) connected with a MODE pin of the ASIC chip (10), and when the ASIC chip (10) detects that an input voltage of the MODE pin, namely an output voltage of the low-voltage protection and safety regulation circuit (100), is lower than a preset threshold voltage, the power optimizer (1) is controlled to be switched to or maintained in a safety working MODE;

a safety adjustment and repair control module (104) in the low-voltage protection and safety adjustment and repair circuit (100) obtains electricity from the photovoltaic power generation unit (5) through a second auxiliary power supply (105) to obtain a working voltage, the safety adjustment and repair control module (104) is used for detecting whether a heartbeat packet communication signal sent by the safety bypass controller (2) is normal or not, if the heartbeat packet communication signal is normal, an adjustment and repair instruction is generated to control to disconnect a normally-closed adjustment and repair switching element (103) in the low-voltage protection and safety adjustment and repair circuit (100) and maintain the normally-closed adjustment and repair switching element in a disconnected state until the heartbeat packet communication signal is judged to be abnormal, and the adjustment and repair switching element (103) is in a disconnected state; if the heartbeat packet communication signal is abnormal, the generation of the adjustment and repair instruction is stopped to control the adjustment and repair switch (103) to be switched off, the adjustment and repair switch (103) is in a switch-on state, and the switch-on state is maintained until the heartbeat packet communication signal is judged to be normal.

2. The pv optimizer apparatus for automatically and rapidly controlling voltage safety according to claim 1, wherein when a fire emergency occurs to a user of a building or a house in which the pv power generation system is installed, the user turns off a grid-connected switch of a grid-connected point of the pv inverter or a house-to-house switch of a house and a power grid, the third switch (s 3) of a normally closed type that draws power from an ac terminal of the pv inverter through the first auxiliary power source (3) is closed due to power loss of the first auxiliary power source (3), a circuit of each pv string in the pv power generation system is short-circuited, when the ASIC chip (10) in the power optimizer (1) detects an input voltage of a MODE pin, that is, an output voltage of the low voltage protection and safety trimming circuit (100), and is lower than a preset threshold voltage, the power optimizer (1) is controlled to switch to or maintain in a safety operation MODE, at which the power optimizer (1) stops outputting power and an output operation voltage, and at which the power optimizer (1) outputs a safety voltage of 0V; after an emergency fault is eliminated, after a user closes the grid-connected switch or an entrance switch of a house and a power grid again, the normally closed third switch (s 3) which gets electricity from the alternating current end of the photovoltaic inverter through the first auxiliary power supply (3) is disconnected due to the restoration of power supply of the first auxiliary power supply (3), the short circuit state of the circuit of each photovoltaic group string of the photovoltaic power generation system is relieved, meanwhile, the safety bypass controller (2) restores to send the heartbeat packet communication signal due to the restoration of the electricity, when the safety debugging control module (104) detects that the heartbeat packet communication signal generated by the safety bypass controller (2) is normal, a debugging command is generated to control and maintain the debugging switch element (103) in a disconnected state, the ASIC chip (10) detects the input voltage of an E pin, namely the output voltage of the low-voltage protection and safety debugging circuit (100), and when the output voltage of the ASIC chip (10) is higher than a preset threshold voltage, the ASIC chip (10) controls the power optimizer (1) to restore to an MPPT working MODE, and the power optimizer (1) recovers to output the MPPT working voltage.

3. The pv optimization device for automatically and rapidly controlling voltage safety according to claim 1, wherein when the pv power generation system is installed or maintained, the pv string is not connected or disconnected, the user turns off or does not turn on the grid-connected switch of the pv inverter grid-connected point, the safety bypass controller (2) stops sending the heartbeat packet communication signal due to stopping power supply, the safety tuning control module (104) does not detect or detects that the heartbeat packet communication signal abnormality occurs in the safety bypass controller (2), the tuning switch (103) is in an on state due to not receiving the tuning command, the MODE pin is turned on with the ground, and when the ASIC chip (10) in the power optimizer (1) detects an input voltage of the MODE pin, that is, an output voltage of the low voltage protection and safety tuning circuit (100), and is lower than a preset threshold voltage, the power optimizer (1) is controlled to switch to or maintain in a safety operation MODE, and the power optimizer (1) outputs a safety output power of 0V and a safety output voltage; after the installation or operation and maintenance of the photovoltaic power generation system is completed, after a user closes the grid-connected switch or the house-to-house switch of the house and the power grid again, the normally-closed third switch (s 3) which gets electricity from the alternating current end of the photovoltaic inverter through the first auxiliary power supply (3) is disconnected due to the restoration of power supply of the first auxiliary power supply (3), the safety bypass controller (2) resends the heartbeat packet communication signal due to the restoration of the electricity, the safety debugging control module (104) generates a debugging instruction to control and maintain the debugging switching element (103) in a disconnected state after detecting that the heartbeat packet communication signal generated by the safety bypass controller (2) is normal, the ASIC chip (10) detects the input voltage of a MODE pin, namely the output voltage of the low-voltage protection and safety debugging circuit (100), and when the output voltage is higher than a preset threshold voltage, the ASIC chip (10) controls the power optimizer (1) to restore to an MPPT working MODE, and the power optimizer (1) restores the output power and outputs the working voltage.

4. The photovoltaic optimization device with automatic fast voltage control safety according to claim 1, wherein the low voltage protection and safety trimming circuit (100) of the power optimizer (1) comprises the trimming switch (103), resistors R1 and R2, a diode VD, a capacitor Cx, and the safety trimming control module (104), the trimming switch (103) is a normally-closed PMOS transistor, a forward body diode is connected between a source and a drain of the PMOS transistor, the source of the trimming switch (103) is grounded, the drain is connected in series with the resistor R1 and then connected to a Mode pin of the ASIC chip (10), and a gate is connected to a signal input end of the safety trimming control module (104); one end of the resistor R2 is connected with a VDD pin of the ASIC chip (10), and the other end of the resistor R2 is connected with a drain electrode of the PMOS tube and is grounded after being connected with the capacitor Cx; the anode of the diode VD is connected with the drain electrode of the PMOS tube, and the cathode of the diode VD is connected with the V0 pin of the chip;

the safety adjustment and repair control module (104) obtains electricity from the photovoltaic power generation unit (5) through the second auxiliary power supply (105) to obtain working voltage, the safety adjustment and repair control module (104) is used for detecting whether the heartbeat packet communication signal generated by the safety bypass controller (2) is normal, and if the heartbeat packet communication signal is normal, an adjustment and repair instruction is generated to control the adjustment and repair switch piece (103) to be disconnected and maintain the disconnection state until the heartbeat packet communication signal is judged to be abnormal; if the heartbeat packet communication signal generated by the safety bypass controller (2) is not detected or the signal abnormality is detected, the generation of a repair instruction is stopped to control the repair switch part (103) to be turned on and off, and the repair switch part (103) is in a turned-on state.

5. The photovoltaic optimization device for automatically and rapidly controlling voltage safety according to claim 1, wherein the method for the ASIC chip (10) to control the power optimizer (1) to switch into the safe operation mode is as follows:

when the ASIC chip (10) detects that the input voltage of the Mode pin of the ASIC chip is lower than the threshold voltage, a first switch (20) in the power optimizer (1) is driven to be turned off and a second switch (30) is driven to be turned on so as to control the photovoltaic power generation unit (5) connected to the power optimizer (1) to stop outputting photovoltaic power and working voltage, and at the moment, the power optimizer (1) outputs 0V safety voltage, so that the running state of the power optimizer (1) is switched to a safety working Mode;

the power optimizer (1) comprises the ASIC chip (10), the first switch (20), the second switch (30), an input capacitor Cin, an output capacitor Cout and an energy storage inductor L, wherein the first switch (20) and the second switch (30) are MOS (metal oxide semiconductor) tubes, and the grid electrode of the first switch (20) is connected with the HD-driver pin of the ASIC chip (10); the grid electrode of the second switch (30) is connected with an LD-driver pin of the ASIC chip (10); one end of the energy storage inductor L is connected with the source electrode of the first switch (20), the other end of the energy storage inductor L is connected with one end of the output capacitor Cout, and the other end of the output capacitor Cout is connected with the source electrode of the second switch (30); the input capacitor Cin is connected in parallel between the positive output end and the negative output end of the photovoltaic power generation unit (5).

6. The photovoltaic optimization device with automatic fast control of voltage safety according to claim 5, characterized in that the ASIC chip (10) internally comprises a maximum power tracking circuit, a reference voltage generation circuit, a mode control circuit, a driving control circuit and an internal chip power supply circuit;

the maximum power tracking circuit comprises a voltage and current detection unit, a multiplier and a maximum power tracking processing unit, wherein the voltage and current detection unit is used for collecting the output voltage and the output current of the accessed photovoltaic power generation unit (5);

the multiplier is used for multiplying the output voltage acquired by the voltage and current detection unit and the output current to obtain the output power of the photovoltaic power generation unit (5);

the input end of the maximum power tracking processing unit is connected with the output end of the multiplier and is used for tracking the maximum power point of the photovoltaic power generation unit (5);

the reference voltage generating circuit is used for providing a reference voltage for determining a duty ratio signal to the maximum power tracking circuit and providing a reference voltage for mode control to the mode control circuit by utilizing the power supply of the chip internal power supply circuit, when the power optimizer (1) operates in an MPPT (maximum power point tracking) working mode, the ASIC chip (10) controls the on-off of the first switch (20) and the second switch (30) according to the duty ratio signal so as to realize the maximum power tracking of the accessed photovoltaic power generation unit (5);

a signal output end of the Mode control circuit is connected with the Mode pin of the ASIC chip (10), a first signal input end (101) of the low-voltage protection and safety trimming circuit (100) on the periphery of the chip is connected with the Mode pin, a second signal input end (102) is connected with a VDD pin of the chip, when an input voltage of the Mode pin of the ASIC chip (10) is lower than a preset threshold voltage, the ASIC chip (10) controls the power optimizer (1) to operate in a safety working Mode, and when the input voltage of the Mode pin of the ASIC chip (10) is higher than the preset threshold voltage, the ASIC chip (10) restores the power optimizer (1) to operate in an MPPT working Mode;

the drive control circuit comprises a logic control unit, a first drive unit and a second drive unit, wherein a first input end of the logic control unit is connected with a signal output end of the mode control circuit, a second input end of the logic control unit is connected with a signal output end of the maximum power tracking unit, a first output end and a second output end of the logic control unit are respectively connected with signal input ends of the first drive unit and the second drive unit, the signal output ends of the first drive unit and the second drive unit are respectively connected with an HD-driver pin and an LD-driver pin of the ASIC chip (10), and the drive control circuit is used for controlling the on-off of the first switch (20) and the second switch (30) according to preset control logic.

7. A method for automatically and rapidly controlling voltage safety applied to a photovoltaic power generation system, which is realized by the photovoltaic optimization device according to any one of claims 1-6, wherein the photovoltaic power generation system comprises a plurality of photovoltaic strings connected to a DC bus of a photovoltaic inverter, the photovoltaic strings are composed of a plurality of photovoltaic modules connected in series, the photovoltaic modules comprise photovoltaic power generation units (5) and power optimizers (1) used for accessing the photovoltaic power generation units (5), the photovoltaic optimization device comprises the power optimizers (1) arranged at the output sides of the photovoltaic power generation units (5) and DC bypass circuits arranged at the output sides of the photovoltaic strings, and the output ends of a plurality of the power optimizers (1) are connected in series to serve as the output ends of the photovoltaic strings; the direct current bypass circuit comprises a safety bypass controller (2), a first auxiliary power source (3) and a third switch (s 3), wherein the third switch (s 3) is connected between a positive input end and a negative input end of a direct current end of the photovoltaic inverter, an electric input end of the first auxiliary power source is connected with an alternating current end of the photovoltaic inverter, and an electric output end of the first auxiliary power source is connected with the third switch (s 3) to supply power for the third switch (s 3);

the power optimizer (1) comprises an ASIC chip (10) and a low-voltage protection and safety regulation circuit (100);

the method for automatically and quickly controlling the voltage safety comprises the following steps:

the ASIC chip (10) in the power optimizer (1) controls the power optimizer (1) to switch to or maintain in a safe working mode when detecting that the output voltage of the low voltage protection and safety trimming circuit (100) is lower than a threshold voltage;

the safety adjustment and repair control module (104) in the low-voltage protection and safety adjustment and repair circuit (100) gets electricity from the photovoltaic power generation unit (5) through a second auxiliary power supply (105) to obtain working voltage, the safety adjustment and repair control module (104) is used for detecting whether heartbeat packet communication signals generated by the safety bypass controller (2) are normal, if the heartbeat packet communication signals are normal, an adjustment and repair instruction is generated to control to disconnect the adjustment and repair switch piece (103) and maintain the adjustment and repair switch piece in a disconnected state until the heartbeat packet communication signals are judged to be abnormal, when the adjustment and repair switch piece is in the disconnected state, the voltage of an output end of the low-voltage protection and safety adjustment and repair circuit (100) is higher than the threshold voltage, the power optimizer (1) is controlled to recover an MPPT working mode, and at the moment, the power optimizer (1) recovers output power and output working voltage.

8. The method for automatic and rapid control of voltage safety for use in photovoltaic power generation systems according to claim 7, characterized in that the method by which the power optimizer (1) is controlled to enter the safe operating mode is:

when the ASIC chip (10) detects that the input voltage of the Mode pin is lower than the threshold voltage, the first switch (20) in the power optimizer (1) is driven to be switched off, and the second switch (30) is driven to be switched on, so that the photovoltaic power generation unit (5) connected to the power optimizer (1) is controlled to stop outputting photovoltaic power and voltage, and the operation state of the power optimizer (1) is switched to or maintained in a safe operation Mode.

9. The method for automatically and rapidly controlling voltage safety applied in a photovoltaic power generation system according to claim 8, wherein when the power optimizer (1) is switched into a safe operation mode for a set duration, the ASIC chip (10) controls the power optimizer (1) to enter a non-operation mode, in which both the first switch (20) and the second switch (30) in the power optimizer (1) are in an off state, at which time the power optimizer (1) will stop outputting power and output operation voltage, and at which time the power optimizer (1) outputs 0V safe voltage.

10. The method for automatic and rapid control of voltage safety for use in photovoltaic power generation systems according to claim 7, characterized in that the method for the controlled entry of the power optimizer (1) into MPPT mode of operation is:

the grid-connected switch is turned on, after the photovoltaic inverter recovers grid connection, the first auxiliary power supply of the direct current bypass circuit recovers power supply, the safety bypass controller (2) controls the third switch (s 3) to be switched off after power is supplied, and meanwhile, the safety bypass controller (2) recovers sending of the heartbeat packet communication signal;

after the safe trimming control module (104) detects the heartbeat packet communication signal generated by the safe bypass controller (2), a trimming instruction is generated to control to switch off the trimming switch (103) and maintain the trimming switch in a disconnected state, when the trimming switch is in the disconnected state, the voltage of the output end of the low-voltage protection and safe trimming circuit (100) is recovered to be higher than the threshold voltage, the power optimizer (1) is controlled to recover the MPPT working mode, and at the moment, the power optimizer (1) recovers the output power and the output working voltage.

11. A photovoltaic power generation system, characterized in that the photovoltaic power generation system is provided with a photovoltaic optimization device for automatically and rapidly controlling voltage safety according to any one of claims 1 to 6.

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