CN116247733A

CN116247733A - Photovoltaic device and power generation system based on dual-operation mode ASIC chip control safety

Info

Publication number: CN116247733A
Application number: CN202310322737.4A
Authority: CN
Inventors: 陈维; 宋悦
Original assignee: Jiangsu Xumax Power Technology Co ltd; Shenzhen Zhongxu New Energy Co ltd
Current assignee: Jiangsu Xumax Power Technology Co ltd; Shenzhen Zhongxu New Energy Co ltd
Priority date: 2022-12-29
Filing date: 2022-12-29
Publication date: 2023-06-09
Also published as: CN115663907A; CN116316849A; CN115663907B

Abstract

The invention discloses a photovoltaic device and a power generation system based on dual-operation mode ASIC chip control safety. The power optimizer in the photovoltaic system has two working modes, namely MPPT maximum power tracking and safety, under the MPPT maximum power tracking working mode of the ASIC chip, the output voltage and current of the photovoltaic module are acquired, then the output power of the photovoltaic module is calculated through an analog multiplier, the maximum power tracking unit adjusts the duty ratio to track the maximum power of the photovoltaic module, and meanwhile, the ASIC chip mode control circuit is used for realizing that when short circuits occur among photovoltaic strings of the power generation system or all photovoltaic strings are connected to the bus of the photovoltaic inverter and other emergency faults occur, all the power optimizers in the power generation system, which are connected with all the photovoltaic power generation units, stop the output voltage and the power, and realize the system safety.

Description

Photovoltaic device and power generation system based on dual-operation mode ASIC chip control safety

Technical Field

The invention relates to the technical field of photovoltaic equipment protection, in particular to a photovoltaic device and a power generation system based on dual-operation mode ASIC chip control safety.

Background

Because the photovoltaic system has a wide distribution range, particularly a distributed photovoltaic system, the photovoltaic system is powered by direct current, and is generally 1000V system voltage, even up to 1500V high voltage. Further, the probability of occurrence of a direct current arc fault (series arc, parallel arc) is increased due to contact drop, device aging, insulation breakage, salt damage, poor grounding, etc., which causes a photovoltaic fire accident caused by the direct current arc fault to not only harm the photovoltaic system equipment but also threaten the safety of residential buildings, industrial and commercial facilities, public facilities, etc.

Photovoltaic inverter products with built-in AFCI (Arc-Fault Circuit-inter) function are proposed by a plurality of groups of series-connected photovoltaic inverter manufacturers in the current market, and the photovoltaic inverter with built-in AFCI Arc detection identifies direct current Arc faults by detecting Arc noise, breaks a direct current Circuit and eliminates arcs. The AFCI is an arc fault breaker, which is a protection device for opening a power supply circuit before an arc fault develops into a fire or the circuit is short-circuited by identifying an arc fault characteristic signal in the circuit. It is noted, however, that the AFCI of a photovoltaic inverter can typically detect, extinguish, and that parallel arcs (short circuit faults) cannot be detected and eliminated by current AFCI functions. Although the module-level quick turn-off technology can disconnect each module in the photovoltaic system, so as to eliminate direct-current high voltage and series-parallel arc faults (short circuit faults) existing in the photovoltaic system array, the current module-level quick turn-off technology cannot quickly eliminate the parallel arc because the AFCI function of the current photovoltaic inverter cannot detect the parallel arc (short circuit faults), the destructive power of the parallel arc is often 10 times that of the series arc, and the potential safety hazard is larger.

Disclosure of Invention

In order to solve the technical problems, the invention provides a power generation device and a power generation system based on dual-working-mode ASIC chip control safety. The maximum power tracking of the photovoltaic module is realized through the mode control unit of the ASIC chip, the generating capacity of the photovoltaic module is improved, and meanwhile, the risk of circuit short-circuit faults (parallel arcs) of the photovoltaic system is solved at low cost.

To achieve the purpose, the invention adopts the following technical scheme:

in one aspect, a photovoltaic device based on dual-operation mode ASIC chip control safety is provided, the photovoltaic device is composed of a plurality of photovoltaic group strings connected on a bus of a photovoltaic inverter in a serial or parallel connection mode, a plurality of photovoltaic components are connected in series or parallel to form the photovoltaic group string, each photovoltaic component comprises a power optimizer and a photovoltaic power generation unit connected to the power optimizer, the power optimizer internally comprises an ASIC chip, and a maximum power tracking circuit, a mode control circuit, a reference operating voltage generation circuit and a drive control circuit which are arranged on the ASIC chip;

the chip is provided with a mode control end, the ASIC chip judges whether the input voltage of the mode control end is lower than a preset mode control voltage threshold value, if so, the ASIC chip controls the power optimizer to switch to a safe working mode or maintain in the safe working mode; if not, keeping the power optimizer to operate in an MPPT maximum power tracking working mode;

The MODE control end is a MODE pin of the ASIC chip.

Preferably, when a short circuit fault occurs between strings of photovoltaic groups of a photovoltaic device or each of the strings of photovoltaic groups is connected in series to a bus of a photovoltaic inverter, the power optimizer in the power generation system executes an automatic protection flow, and the specific method is as follows:

the ASIC chip in the power optimizer detects whether the input voltage of its Mode pin is below a preset Mode control voltage threshold,

if yes, the ASIC chip controls the power optimizer to switch to a safe working mode or keeps running in the safe working mode;

if not, keeping the power optimizer to recover or maintain running in the MPPT maximum power tracking working mode;

when the ASIC chip detects that the input voltage value of the Mode pin is lower than a preset Mode control voltage threshold value, a first switch in the power optimizer is driven to be disconnected and a second switch is driven to be connected so as to control a photovoltaic power generation unit connected with the power optimizer to stop outputting photovoltaic power, and therefore the operation state of the power optimizer is switched to the safe working Mode.

Preferably, the MODE control circuit is connected to a MODE control circuit at the periphery of the ASIC chip through the MODE pin of the ASIC chip, and the MODE control circuit is composed of a first resistor, a second resistor, a grounded capacitor and a low-voltage protection diode, wherein a first end of the first resistor is connected to the MODE pin of the ASIC chip, and a second end of the first resistor is connected to a first end of the second resistor, a first end of the grounded capacitor and an anode of the low-voltage protection diode; the second end of the grounding capacitor is connected with a grounding pin of the ASIC chip; the cathode of the low-voltage protection diode is connected with a Vo pin of the ASIC chip, and the Vo pin provides output voltage information of the power optimizer for the ASIC chip; the second end of the second resistor is connected with a VDD pin of the ASIC chip, and the VDD pin provides reference working voltage inside the ASIC chip.

Preferably, when the output voltage value of the power optimizer is higher than the internal reference operating voltage value of the ASIC chip, the low-voltage protection diode of the MODE control circuit will be in an off state, and the voltage of the MODE pin of the ASIC chip is provided by the VDD pin of the ASIC chip, and the value thereof is the internal reference operating voltage value of the ASIC chip;

when the output voltage value of the power optimizer is lower than the reference working voltage value inside the ASIC chip, the low-voltage protection diode of the MODE control circuit is in a conducting state, and the output voltage value of the power optimizer is led into the MODE pin of the ASIC chip by the MODE control circuit, wherein the value of the output voltage value of the power optimizer is the sum of the output voltage value of the power optimizer and the voltage drop of the low-voltage protection diode.

Preferably, when the input voltage value of the MODE pin of the ASIC chip is higher than a preset MODE control voltage threshold, the ASIC chip operates in an MPPT maximum power tracking working MODE, and when the input voltage value of the MODE pin of the ASIC chip is lower than a preset MODE control voltage threshold, the ASIC chip operates in a safety MODE, and the preset MODE control voltage threshold is smaller than an internal reference working voltage value of the ASIC chip.

Preferably, when a short-circuit fault occurs in the electrical circuit of the photovoltaic device,

the power optimizer automatically enters the safe operating mode:

Preferably, the method for controlling the power optimizer to enter the non-working mode comprises the following steps:

and when the power optimizer is switched into the safe working mode for a set duration, the ASIC chip controls the power optimizer to enter a non-working mode, and the non-working mode drives a first switch in the power optimizer to be disconnected and drives a second switch to be disconnected.

Preferably, when a short-circuit fault occurs between strings of photovoltaic groups of the photovoltaic device or after the strings of the photovoltaic groups are connected in series to a bus of the photovoltaic inverter, the power optimizer executes an MPPT maximum power tracking working mode recovery flow, and the specific method comprises the following steps:

After the short-circuit fault is relieved, the ASIC chip in the power optimizer detects whether the input voltage of a Mode pin of the ASIC chip is higher than or equal to the preset Mode control voltage threshold value,

if yes, the ASIC chip controls the power optimizer to recover from the non-working mode to the MPPT maximum power tracking working mode;

if not, keeping the power optimizer operating in the non-working mode.

Preferably, the power optimizer comprises a power optimizer, an independent photovoltaic module is formed after the power optimizer is connected with a photovoltaic power generation unit, the power optimizer comprises an ASIC chip, the ASIC chip comprises a voltage and current detection unit, a multiplier and a maximum power tracking unit, a first input end I1, a second input end I2, a third input end I3 and a fourth input end I4 of the voltage and current detection unit are respectively connected with a Switch-H pin, a Switch-L pin, a Vo pin and an AGND pin of the ASIC chip, and a sampling current signal output end Iout and a sampling voltage signal output end Vout of the voltage and current detection unit are respectively connected with a first input end and a second input end of the multiplier; the power output end Pout of the multiplier is connected with the power signal input end of the maximum power tracking processing unit;

The voltage and current detection unit is used for collecting output voltage and output current of the photovoltaic power generation unit;

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

the maximum power tracking unit is used for tracking the maximum power point of the photovoltaic power generation unit based on the output power output by the multiplier.

On the other hand, the power generation system based on the dual-operation mode ASIC chip control safety is provided, the power generation system is composed of a plurality of photovoltaic group strings connected on a bus of a photovoltaic inverter in a serial or parallel connection mode, a plurality of photovoltaic modules are connected in series or parallel to form the photovoltaic group strings, each photovoltaic module comprises a power optimizer and a photovoltaic power generation unit connected to the power optimizer, the power optimizer internally comprises an ASIC chip, the ASIC chip comprises a voltage and current detection unit, a multiplier and a maximum power tracking processing unit, the voltage and current detection unit is used for collecting output voltage and output current of the photovoltaic power generation unit, the multiplier is used for multiplying the output voltage and the output current collected by the voltage and current detection unit to obtain output power of the photovoltaic power generation unit, and the maximum power tracking processing unit is used for tracking the maximum power point of the photovoltaic power generation unit based on the output power output by the multiplier.

Preferably, the power optimizer further comprises a first switch, a 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 transistors, and a gate of the first switch is connected with an 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; the input capacitor Cin is connected in parallel between the positive output end and the negative output end of the photovoltaic power generation unit;

when a short circuit occurs between photovoltaic group strings of a power generation system or each photovoltaic group string is connected in series with a bus of a photovoltaic inverter, a power optimizer in the power generation system executes an automatic protection flow, and the specific method is as follows:

the ASIC chip in the power optimizer determines if the input voltage of its Mode pin is below a preset Mode control voltage threshold due to a short circuit,

if yes, the ASIC chip controls the power optimizer to switch to a safe working mode;

if not, keeping the power optimizer to operate in an MPPT maximum power tracking working mode;

The method for the power optimizer to enter the safe working mode comprises the following steps:

when the ASIC chip detects that the input voltage of a Mode pin is lower than a preset Mode control voltage threshold value, a first switch in the power optimizer is driven to be disconnected and a second switch is driven to be connected so as to control a photovoltaic power generation unit connected with the power optimizer to stop outputting photovoltaic power, and therefore the operation state of the power optimizer is switched to the safe working Mode.

Preferably, the ASIC chip internally comprises a maximum power tracking circuit, a reference voltage generating circuit, a mode control circuit, a drive control circuit and an internal 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 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 a reference voltage for determining a duty ratio signal for the maximum power tracking processing unit by utilizing the power supply of the chip internal power supply circuit and providing a reference voltage for mode control for the mode control circuit, and when the power optimizer operates in an MPPT maximum power tracking working mode, the ASIC chip controls the on-off of the first switch and the second switch according to the duty ratio signal so as to realize maximum power tracking of the accessed photovoltaic power generation unit;

the signal output end of the Mode control circuit is connected with the Mode pin of the ASIC chip, when the input voltage of the Mode pin of the ASIC chip is lower than the preset Mode control voltage threshold value, the ASIC chip controls the power optimizer to operate in a safe working Mode, and when the input voltage of the Mode pin of the ASIC chip reaches the reference voltage, the ASIC chip resumes the power optimizer to operate in an MPPT maximum power tracking 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, the first output end and the second output end 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, 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 power optimizer provided by the invention adopts the sampling circuit (voltage and current detection unit) of the ASIC chip to acquire the output voltage and the output current of the photovoltaic module, then calculates the output power of the photovoltaic module through the analog multiplier, and adjusts the duty ratio by the maximum power tracking unit so as to realize MPPT maximum power tracking of the photovoltaic module, thereby avoiding the problems of complex structure of internal devices of the power optimizer, high production and use cost of the power optimizer due to the need of carrying out analog-digital conversion and the like when the digital chip such as MCU is used for carrying out maximum power point tracking in the existing scheme.

Drawings

In order to more clearly illustrate the technical solution of the embodiments of the present invention, the drawings that are required to be used in the embodiments of the present invention will be briefly described below. It is evident that the drawings described below are only some embodiments of the present invention and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.

FIG. 1 is a schematic diagram of a power generation system based on dual operation mode ASIC chip control security according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a dual-operation mode ASIC chip control safety-based power generation system that performs an active protection process when a short circuit occurs in a photovoltaic string;

FIG. 3 is a schematic diagram of a dual-operation mode ASIC chip control safety based power generation system that performs a passive protection process after creating a short circuit environment;

FIG. 4 is a schematic diagram of the internal circuit structure of an ASIC chip;

fig. 5 is a schematic diagram of a power optimizer operating in an MPPT maximum power tracking mode of operation;

FIG. 6 is a schematic diagram of the power optimization device operating in a safe mode of operation;

fig. 7 is a schematic diagram of the power optimizing apparatus operating in a non-operating mode.

Detailed Description

The technical scheme of the invention is further described below by the specific embodiments with reference to the accompanying drawings.

Wherein the drawings are for illustrative purposes only and are shown in schematic, non-physical, and not intended to be limiting of the present patent; for the purpose of better illustrating embodiments of the invention, certain elements of the drawings may be omitted, enlarged or reduced and do not represent the size of the actual product; it will be appreciated 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 numbers in the drawings of embodiments of the 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. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, only for convenience in describing the present invention and simplifying the description, rather than indicating or implying that the apparatus or elements being referred to must have a specific orientation, be constructed and operated in a specific orientation, so that the terms describing the positional relationships in the drawings are merely for exemplary illustration and should not be construed as limiting the present patent, and that the specific meaning of the terms described above may be understood by those of ordinary skill in the art according to specific circumstances.

In the description of the present invention, unless explicitly stated and limited otherwise, the term "coupled" or the like should be interpreted broadly, as it may be fixedly coupled, detachably coupled, or integrally formed, as indicating the relationship of components; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between the two parts or interaction relationship between the two parts. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

The invention provides a photovoltaic device based on dual-working mode ASIC chip control safety, as shown in fig. 1 and 2, the photovoltaic device is composed of a plurality of photovoltaic group strings connected on a bus of a photovoltaic inverter in a serial or parallel mode, a plurality of photovoltaic modules are connected in series or parallel to form the photovoltaic group string, each photovoltaic module comprises a power optimizer and a photovoltaic power generation unit connected into the power optimizer, the power optimizer internally comprises an ASIC chip 10, and a maximum power tracking circuit, a mode control circuit, a reference working voltage generation circuit and a drive control circuit which are arranged on the ASIC chip 10;

The ASIC chip 10 sets a mode control end, the ASIC chip 10 judges whether the input voltage of the mode control end is lower than a preset mode control voltage threshold, if yes, the ASIC chip controls the power optimizer to switch to a safe working mode or maintain in the safe working mode; if not, keeping the power optimizer to operate in an MPPT maximum power tracking working mode;

the MODE control terminal is a MODE pin of the ASIC chip 10.

When a short circuit fault occurs between strings of photovoltaic groups of a photovoltaic device or each string of the photovoltaic groups is connected in series with a bus of a photovoltaic inverter to generate a short circuit, the power optimizer in the power generation system executes an automatic protection flow, and the specific method comprises the following steps:

the ASIC chip 10 in the power optimizer detects whether the input voltage of its Mode pin is below a preset Mode control voltage threshold,

if yes, the ASIC chip 10 controls the power optimizer to switch to a safe working mode or maintain operation in the safe working mode;

when the ASIC chip 10 detects that the input voltage value of the Mode pin is lower than the preset Mode control voltage threshold, the first switch 20 in the power optimizer is driven to be turned off and the second switch 30 is driven to be turned on, so as to control the photovoltaic power generation unit connected with the power optimizer to stop outputting photovoltaic power, thereby realizing switching the operation state of the power optimizer into the safe working Mode.

The MODE control circuit is connected to a MODE control circuit at the periphery of the ASIC chip 10 through the MODE pin of the ASIC chip 10, and the MODE control circuit is composed of a first resistor, a second resistor, a grounded capacitor and a low-voltage protection diode, wherein a first end of the first resistor is connected to the MODE pin of the ASIC chip 10, and a second end of the first resistor is connected to a first end of the second resistor, a first end of the grounded capacitor and an anode of the low-voltage protection diode; the second end of the grounding capacitor is connected with a grounding pin of the ASIC chip 10; the cathode of the low-voltage protection diode is connected with a Vo pin of the ASIC chip 10, and the Vo pin provides the output voltage information of the power optimizer for the ASIC chip 10; the second end of the second resistor is connected to the VDD pin of the ASIC chip 10, and the VDD pin provides the reference operating voltage inside the ASIC chip 10.

When the output voltage value of the power optimizer is higher than the internal reference operating voltage value of the ASIC chip 10, the low-voltage protection diode of the MODE control circuit will be in an cut-off state, and the voltage of the MODE pin of the ASIC chip 10 is provided by the VDD pin of the ASIC chip 10, and the value thereof is the internal reference operating voltage value of the ASIC chip 10;

When the output voltage value of the power optimizer is lower than the reference operating voltage value inside the ASIC chip 10, the low-voltage protection diode of the MODE control circuit will be in a conducting state, and the output voltage value of the power optimizer is introduced into the MODE pin of the ASIC chip 10 by the MODE control circuit, and the value of the output voltage value of the power optimizer is the sum of the voltage drop of the low-voltage protection diode.

When the input voltage value of the MODE pin of the ASIC chip 10 is higher than a preset MODE control voltage threshold, the ASIC chip 10 operates in an MPPT maximum power tracking operation MODE, and when the input voltage value of the MODE pin of the ASIC chip 10 is lower than the preset MODE control voltage threshold, the ASIC chip 10 operates in a safety MODE, wherein the preset MODE control voltage threshold is smaller than the internal reference operation voltage value of the ASIC chip 10.

When a short circuit fault occurs in the electrical circuit of the photovoltaic device,

the power optimizer automatically enters the safe operating mode:

when the ASIC chip 10 detects that the input voltage value of the Mode pin is lower than the reference voltage and reaches the preset Mode control voltage threshold, the first switch 20 in the power optimizer is driven to be turned off and the second switch 30 is driven to be turned on, so as to control the photovoltaic power generation unit connected with the power optimizer to stop outputting photovoltaic power, and thus the operation state of the power optimizer is switched to the safe working Mode.

The method for the power optimizer to enter the non-working mode comprises the following steps:

when the power optimizer is switched into the safe operation mode for a set duration, the ASIC chip 10 controls the power optimizer to enter a non-operation mode, which drives the first switch 20 in the power optimizer to open and the second switch 30 to open.

When a short circuit fault occurs between strings of photovoltaic groups of a photovoltaic device or after the short circuit fault is relieved when a bus of a photovoltaic inverter is connected in series with each photovoltaic group, the power optimizer executes an MPPT maximum power tracking working mode recovery flow, and the specific method comprises the following steps:

after the short-circuit fault is relieved, the ASIC chip 10 in the power optimizer detects whether the input voltage of the Mode pin thereof is higher than or equal to the preset Mode control voltage threshold,

if not, keeping the power optimizer operating in the non-working mode.

In another embodiment of the present invention, as shown in fig. 1, the power generation system based on dual-operation mode ASIC chip control safety is formed by a plurality of photovoltaic strings 300 connected in series or parallel on a bus of a photovoltaic inverter 4, and a plurality of photovoltaic modules are connected in series or parallel to form the photovoltaic string 300, each photovoltaic module includes a power optimizer 1 and a photovoltaic power generation unit 5 connected to the power optimizer, the power optimizer is internally shown in fig. 5-7, and includes an ASIC chip 10, as shown in fig. 4, the ASIC chip 10 includes a voltage-current detection unit, a multiplier and a maximum power tracking unit, the voltage-current detection unit is used for collecting an output voltage and an output current of the photovoltaic power generation unit, the multiplier is used for multiplying the output voltage and the output current collected by the voltage-current detection unit to obtain an output power of the photovoltaic power generation unit, and the maximum power tracking processing unit is used for tracking a maximum power point of the photovoltaic power generation unit based on the output power output by the multiplier.

In order to track the maximum power point of the photovoltaic power generation unit, as shown in fig. 4, the ASIC chip 10 includes a reference voltage generating circuit, a mode control circuit, a driving control circuit, a communication interface circuit and an internal power supply circuit in addition to a voltage and current detecting unit, a multiplier and a maximum power tracking processing unit,

the reference voltage generating circuit is used for providing a reference voltage for determining a duty ratio signal for the maximum power tracking processing unit by utilizing the power supply of the power supply circuit in the chip and providing a reference voltage for mode control for the mode control circuit, and when the power optimizer operates in the MPPT maximum power 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;

the signal output end of the Mode control circuit is connected with a Mode pin of the ASIC chip, when the input voltage of the Mode pin of the ASIC chip 10 is lower than a preset Mode control voltage threshold value, the ASIC chip 10 controls the power optimizer to operate in a safe working Mode, and when the input voltage of the Mode pin of the ASIC chip 10 reaches the preset Mode control voltage threshold value, the ASIC chip 10 resumes the power optimizer to operate in an MPPT maximum power tracking working Mode;

The drive 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, the first output end and the second output end are respectively connected with the signal input ends of the first driving unit and the second driving unit, the 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 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;

the communication interface circuit is used for providing a communication interface for connecting an external device to the ASIC chip 10.

In summary, the output voltage and the output current of the photovoltaic module are acquired by adopting the sampling circuit (the voltage and current detection unit) of the ASIC chip, then the output power of the photovoltaic module is calculated by the analog multiplier, the maximum power tracking unit adjusts the duty ratio to realize MPPT maximum power tracking of the photovoltaic module, and the problems that the internal device structure of the power optimizer is complex and the production and use cost of the power optimizer is high due to the need of carrying out analog-digital conversion and the like when the digital chip such as MCU is used for carrying out maximum power point tracking in the existing scheme are avoided.

Aiming at the principle of MPPT maximum power tracking of a photovoltaic module by using the ASIC chip, the invention also provides a power generation system based on double-working-mode ASIC chip control safety, which comprises a power optimizer for carrying out MPPT maximum power tracking flow on an accessed photovoltaic power generation unit, wherein the flow specifically comprises the following steps:

s1, a voltage and current detection unit in an ASIC chip 10 inside a power optimizer collects output voltage and output current of a photovoltaic power generation unit;

s2, multiplying the output voltage and the output current acquired by the voltage and current detection unit by a multiplier in the ASIC chip to obtain the output power of the photovoltaic power generation unit;

and S3, the maximum power tracking unit in the ASIC chip is used for tracking the maximum power point of the photovoltaic power generation unit based on the output power output by the multiplier.

When short circuit phenomena such as parallel arcs occur among strings of photovoltaic groups, in order to actively realize quick turn-off of the photovoltaic assembly level, preferably, the power optimizer provided by the embodiment further comprises a peripheral circuit of the ASIC chip 10 shown in fig. 5-7, the peripheral circuit comprises a first switch 20, a second switch 30, an input capacitor Cin, an output capacitor Cout and an energy storage inductor L, the first switch 20 and the second switch 30 are MOS transistors, and a gate of the first switch 20 is connected with an HD-driver pin of the ASIC chip; the grid of the second switch 30 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 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;

When a short circuit occurs between photovoltaic strings of the power generation system or each photovoltaic string is connected to a bus of the photovoltaic inverter, a power optimizer in the power generation system executes an active protection flow, and the specific method is as follows:

the ASIC chip 10 in the power optimizer determines if the input voltage of its Mode pin is below a preset Mode control voltage threshold due to a short,

if so, the ASIC chip 10 controls the power optimizer to switch to the safe operation mode shown in FIG. 6;

if not, keeping the power optimizer running in the MPPT maximum power tracking working mode shown in FIG. 5;

the method for controlling the power optimizer to enter the safe working mode comprises the following steps:

when the ASIC chip 10 detects that the input voltage of the Mode pin is lower than the preset Mode control voltage threshold, the first switch 20 in the power optimizer is driven to be disconnected and the second switch 30 is driven to be connected so as to control the photovoltaic power generation unit connected with the power optimizer to stop outputting photovoltaic power, and therefore the operation state of the power optimizer is switched to a safe working Mode.

The following illustrates the principle of the ASIC chip actively controlling the power optimizer to switch to a safe operating mode when a short circuit phenomenon such as parallel arcs occurs between strings of photovoltaic modules:

Assuming that the outgoing line of the photovoltaic string 300 shown in fig. 2 is short-circuited due to the occurrence of a parallel arc, the parallel arc voltage at the short-circuit fault point is about 0V-40V, at this time, the output voltage of the power optimizer at the front stage of the short-circuit fault point is reduced to be close to 0-1.05V, at this time, the diode VD in the peripheral circuit of the power optimizer shown in fig. 5-6 is turned on, the voltage of the Mode pin potential of the ASIC chip 10 is pulled down to 0.5-1.55V, and is lower than the 2.5V safety voltage threshold of the preset Mode pin, and the ASIC chip 10 switches the power optimizer to the safety operation Mode based on this condition, by: the first switch 20 of the power optimizer is driven to be disconnected by the drive control circuit in the control part, the second switch 30 is driven to be connected to the photovoltaic power generation unit of the power optimizer, so that the output of photovoltaic power is stopped (namely, the photovoltaic power generation unit is switched to a safe working mode), and the hidden danger of arc pulling fire caused by circuit short-circuit faults of the photovoltaic group strings can be effectively avoided. The process of switching to the safe working mode does not need extra triggering action, does not need an expensive arc signal detection device to detect the parallel arc faults generated by the power generation system, but the ASIC chip can timely find out the short circuit faults based on the fluctuation characteristics of the output voltage and the output current of the photovoltaic module, and can rapidly shut off the corresponding photovoltaic group strings after the short circuit faults are found out, so that the operation safety of the power generation system is ensured.

To ensure that other strings of photovoltaic strings that do not have a short circuit fault continue to generate electricity normally, strings of photovoltaic strings that are connected to the bus of the photovoltaic inverter are preferably isolated by anti-reflection diode 400 shown in fig. 1.

Aiming at the principle that the power optimizer in the power generation system actively executes the component level quick turn-off, the invention correspondingly provides a power generation system based on a double-working mode ASIC chip, when short circuit occurs between photovoltaic group strings of the power generation system or when the photovoltaic group strings are connected into buses of the photovoltaic inverter, the power optimizer in the power generation system executes an active protection flow, and the specific method is as follows:

if yes, the ASIC chip 10 controls the power optimizer to switch to a safe working mode;

In order to passively realize rapid turn-off of the photovoltaic module stage when the emergency shutdown of the power generation system is required for a fire disaster of a building in which the power generation system is installed, preferably, the power generation system further includes a third switch s3 and an auxiliary power supply 3 as shown in fig. 1 to 3, the third switch s3 is connected between a positive input terminal and a negative input terminal of a direct current terminal of the photovoltaic inverter 4, an electric input terminal of the auxiliary power supply 3 is connected with an alternating current terminal of the photovoltaic inverter, an electric output terminal of the auxiliary power supply 3 is connected with the third switch s3 to supply power to the third switch s3, and when the emergency failure of the power generation system occurs, the power optimizer executes the passive protection procedure by creating a short circuit environment required by the passive protection procedure, and the specific method is as follows:

a grid-connected switch for manually cutting off the grid connection point of the alternating current inverter or a household switch for a house and a power grid, wherein a normally-closed third switch s3 for taking power from the alternating current end of the photovoltaic inverter through an auxiliary power supply is closed due to the power failure of the auxiliary power supply, all photovoltaic strings in the power generation system are in short circuit, and when the input voltage of a Mode pin of an ASIC chip in each power optimizer is lower than a reference voltage and reaches a preset Mode control voltage threshold value, the ASIC chip controls the corresponding power optimizer to switch from an MPPT maximum power tracking working Mode to a safe working Mode shown in fig. 6 or a non-working Mode shown in fig. 7;

When the grid-connected switch or the household switch is closed after the fault removal, the normally-closed third switch s3 which is powered from the alternating-current end of the photovoltaic inverter through the auxiliary power supply is disconnected due to the recovery of the power supply of the auxiliary power supply, the short-circuit environment is relieved, and when the ASIC chip 10 judges that the input voltage of the Mode pin of the ASIC chip is recovered to the reference voltage, the corresponding power optimizer is controlled to recover to the MPPT maximum power tracking working Mode shown in fig. 5.

The method for controlling the ASIC chip 10 to switch to the secure operation mode by the power optimizer is described in the active security protection procedure described above, and will not be described herein. After the ASIC chip 10 controls the power optimizer to operate in the safe operation mode for 30 seconds, the ASIC chip 10 controls the power optimizer to enter a shutdown non-operation mode as shown in fig. 7, at which time the drive control circuit controls the first switch 20 and the third switch 30 to be turned off together, and the photovoltaic string stops transmitting photovoltaic power.

The following illustrates the principle of the ASIC chip 10 passively controlling the switching of the power optimizer to a safe mode of operation after a human emergency shutdown of the power generation system:

assuming that when an emergency such as a building fire occurs and needs to reduce the output voltage of the photovoltaic string to a safe voltage, firstly, creating a short circuit environment (the creation Mode is specifically described in the above description and is not repeated) required by the ASIC chip to execute a passive protection process, under the short circuit environment, the output voltage of the power optimizer approaches 0V, at this time, the diode VD in the peripheral circuit of the power optimizer as shown in fig. 5-6 is turned on, the voltage of the Mode pin potential of the ASIC chip is reduced to approach 0V and is lower than the preset safe voltage threshold (i.e., the preset Mode control voltage threshold) of the Mode pin, and the ASIC chip switches the power optimizer to the safe working Mode based on this condition, where the switching method is as follows: the drive control circuit inside the control unit drives the first switch 20 of the power optimizer to be turned off and drives the second switch 30 to be turned on, and the photovoltaic power generation unit connected to the power optimizer stops outputting photovoltaic power (i.e., switches to a safe operation mode). The passive safety protection process above can realize the quick turn-off of the component level when the emergency faults such as building fire occur, reduces the output voltage of all photovoltaic strings to 0V, avoids the high requirement of continuous and reliable heartbeat signal acquisition by using the conventional quick turn-off of the watchdog, and does not need continuous transmission of heartbeat communication signals through a power carrier communication (PLC) circuit (in the prior art, U.S. patent No. 8933321B2 filed by Tigo Energy company discloses a watchdog unit of a local controller based on the watchdog technology, which comprises a plurality of solar modules connected to an inverter, a power bus is configured to monitor communication from a central controller far away from the solar modules and determine whether the communication has been interrupted for a period of time exceeding a preset allowable skip number; the system includes a central controller configured to receive a communication from a solar module, and at least one switch configured to disconnect the solar module from a power bus in response to a determination by the location controller that the communication from the central controller has been interrupted for a period of time exceeding a predetermined allowable hop count, wherein the watchdog unit is configured to connect the solar module to the power bus when the communication is not interrupted. And requires configuration of the local receiving unit that the remote PLC transmits).

Aiming at the principle that the power optimizer in the power generation system is turned off rapidly at the level of a passive execution component, the invention correspondingly provides a power generation system based on dual-working-mode ASIC chip control safety, when the power generation system has an emergency fault, the power optimizer in the power generation system executes a passive protection flow by creating a short circuit environment required by the passive protection flow, so that the power optimizer executes the passive protection flow, and the method specifically comprises the following steps:

l1, manually cutting off a grid-connected switch of a photovoltaic inverter grid-connected side connected with a photovoltaic string or a household switch connected with a power grid, closing a normally closed third switch s3 which is powered from an alternating-current end of the photovoltaic inverter through an auxiliary power supply due to power failure of the auxiliary power supply, wherein the third switch s3 is connected between a positive input end and a negative input end of a direct-current side of the photovoltaic inverter, and after the third switch s3 is closed, each photovoltaic string connected to a direct-current bus of the photovoltaic inverter is short-circuited;

l2, the ASIC chip 10 in the power optimizer determines if the input voltage of its Mode pin is below a preset Mode control voltage threshold due to a short,

if yes, the ASIC chip controls the power optimizer to switch to a safe working mode or a non-working mode;

If not, keeping the power optimizer operating in the MPPT maximum power tracking working mode.

After the created short circuit environment is relieved, the power optimizer executes the MPPT maximum power tracking working mode recovery flow, and the specific method is as follows:

after the short circuit environment is relieved, the ASIC chip in the power optimizer judges whether the input voltage of the Mode pin of the ASIC chip is lower than a preset Mode control voltage threshold value,

if yes, the ASIC chip controls the power optimizer to recover from a safe working mode or a non-working mode to an MPPT maximum power tracking working mode;

if not, keeping the power optimizer to operate in a safe working mode or a non-working mode;

the method for restoring the maximum power tracking (MPPT) working mode of the power optimizer comprises the following steps:

when the ASIC chip detects that the input voltage of the Mode pin is lower than the preset Mode control voltage threshold, the first switch 20 in the power optimizer shown in fig. 5 is driven to be closed and the second switch 30 is driven to be opened, so that the photovoltaic power generation unit connected to the power optimizer is controlled to recover the output photovoltaic power, and the operation state of the power optimizer is recovered to the MPPT maximum power tracking working Mode.

The method for relieving the created short circuit environment comprises the following steps:

After a grid-connected switch of a grid connection point of an alternating current inverter or a household switch of a house and a power grid is closed, a normally-closed third switch s3 which is powered from an alternating current end of a photovoltaic inverter through an auxiliary power supply is disconnected due to power restoration of the auxiliary power supply, the third switch s3 is connected between a positive input end and a negative input end of a direct current side of the photovoltaic inverter, and after the third switch s3 is disconnected, a short circuit environment is relieved.

It should be understood that the above description is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be apparent to those skilled in the art that various modifications, equivalents, variations, and the like can be made to the present invention. However, such modifications are intended to fall within the scope of the present invention without departing from the spirit of the present invention. In addition, some terms used in the specification and claims of the present application are not limiting, but are merely for convenience of description.

Claims

1. The photovoltaic device based on the double-working-mode ASIC chip control safety comprises a power optimizer, wherein the power optimizer is connected with a photovoltaic module formed by photovoltaic power generation units, and is characterized in that the photovoltaic device is formed by a plurality of photovoltaic group strings connected on a bus of a photovoltaic inverter in a serial or parallel mode, the photovoltaic group strings are formed by connecting a plurality of photovoltaic modules in series or parallel mode, each photovoltaic module comprises the power optimizer and the photovoltaic power generation units connected with the power optimizer, the power optimizer comprises an ASIC chip (10) inside, and a maximum power tracking circuit, a mode control circuit, a reference working voltage generation circuit and a drive control circuit which are arranged on the ASIC chip (10);

The ASIC chip (10) is provided with a mode control end, the ASIC chip (10) judges whether the input voltage of the mode control end is lower than a preset mode control voltage threshold value, if so, the ASIC chip (10) controls the power optimizer to switch to a safe working mode or maintain in the safe working mode; if not, keeping the power optimizer to operate in an MPPT maximum power tracking working mode;

the MODE control end is a MODE pin of the ASIC chip (10);

the MODE control circuit is connected with a MODE control circuit (40) at the periphery of the ASIC chip (10) through the MODE pin of the ASIC chip (10);

the power optimizer comprises an ASIC chip, the ASIC chip comprises a voltage and current detection unit, a multiplier and a maximum power tracking unit, a first input end I1, a second input end I2, a third input end I3 and a fourth input end I4 of the voltage and current detection unit are respectively connected with a Switch-H pin, a Switch-L pin, a Vo pin and an AGND pin of the ASIC chip, and a sampling current signal output end Iout and a sampling voltage signal output end Vout of the voltage and current detection unit are respectively connected with a first input end and a second input end of the multiplier; the power output end Pout of the multiplier is connected with the power signal input end of the maximum power tracking processing unit;

2. The power generation system based on double-working-mode ASIC chip control safety is characterized by comprising a plurality of photovoltaic group strings connected on a bus of a photovoltaic inverter in a serial or parallel mode, wherein a plurality of photovoltaic assemblies are connected in series or parallel to form the photovoltaic group string, each photovoltaic assembly comprises a power optimizer and a photovoltaic power generation unit connected into the power optimizer, the power optimizer internally comprises an ASIC chip (10), the ASIC chip (10) comprises a voltage and current detection unit, a multiplier and a maximum power tracking processing unit, the voltage and current detection unit is used for collecting output voltage and output current of the photovoltaic power generation unit, the multiplier is used for multiplying the output voltage and the output current collected by the voltage and current detection unit to obtain output power of the photovoltaic power generation unit, and the maximum power tracking processing unit is used for tracking the maximum power point of the photovoltaic power generation unit based on the output power output by the multiplier;

The power optimizer further comprises a first switch (20), a 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 a grid electrode of the first switch (20) is connected with an HD-driver pin of the ASIC chip; 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;

the ASIC chip (10) in the power optimizer determines whether the input voltage of its Mode pin is below a preset Mode control voltage threshold due to a short circuit,

when the ASIC chip (10) detects that the input voltage of a Mode pin is lower than a preset Mode control voltage threshold value, a first switch (20) in the power optimizer is driven to be disconnected and a second switch (30) is driven to be connected so as to control a photovoltaic power generation unit connected with the power optimizer to stop outputting photovoltaic power, and therefore the operation state of the power optimizer is switched to the safe working Mode.

3. The dual operation mode ASIC chip based control security power generation system of claim 2 wherein said ASIC chip (10) internally includes a maximum power tracking circuit, a reference voltage generation circuit, a mode control circuit, a drive control circuit and an on-chip power supply circuit,

the reference voltage generating circuit is used for providing a reference voltage for determining a duty ratio signal for the maximum power tracking processing unit by utilizing the power supply of the chip internal power supply circuit and providing a reference voltage for mode control for the mode control circuit, and when the power optimizer operates in an MPPT maximum power 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;

the signal output end of the Mode control circuit is connected with the Mode pin of the ASIC chip (10), when the input voltage of the Mode pin of the ASIC chip (10) is lower than the preset Mode control voltage threshold value, the ASIC chip (10) controls the power optimizer to operate in a safe working Mode, and when the input voltage of the Mode pin of the ASIC chip (10) reaches the reference voltage, the ASIC chip (10) resumes the power optimizer to operate in an MPPT maximum power tracking 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, the first output end and the second output end 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.