WO2019127022A1

WO2019127022A1 - Optimizer, photovoltaic power generation system and photovoltaic power generation control method

Info

Publication number: WO2019127022A1
Application number: PCT/CN2017/118657
Authority: WO
Inventors: 骆孝龙; 丁永强; 吴良材; 程浩
Original assignee: 深圳古瑞瓦特新能源股份有限公司
Priority date: 2017-12-26
Filing date: 2017-12-26
Publication date: 2019-07-04

Abstract

An optimizer (10), a photovoltaic power generation system and a photovoltaic power generation control method. The optimizer comprises a positive electrode branch (101), a negative electrode branch (102), a first voltage sensor (131), a first capacitor (151), a second voltage sensor (132), a second capacitor (152), an optimizer switch (12), an optimizer controller (11) and a third current sensor (143) or a first current sensor (141) and a second current sensor (142). The photovoltaic power generation system comprises a photovoltaic string unit (01), a photovoltaic inverter (02), a wake-up power source (03) and a wake-up switch (04); The photovoltaic string unit includes at least one group of photovoltaic panels and said optimizer. The optimizer overcomes the disadvantages that a weak electrical signal has a short communication transmission distance, easily affected communication robustness and high communication costs, and thus a dedicated weak electrical signal communication module can be omitted, reducing communication costs of a distributed photovoltaic power generation system.

Description

Optimizer, photovoltaic power generation system and photovoltaic power generation control method

Technical field

The invention relates to the field of photovoltaic power generation, and particularly relates to an optimizer, a photovoltaic power generation system and a photovoltaic power generation control method.

Background technique

Distributed photovoltaic power generation systems have high requirements for safety management on the DC side. Usually, the optimizer can have a DC/DC power conversion circuit with Buck/Boost/Buck-Boost, and the inverter can be boosted by DC-DC and inverse. Variable DC-AC two-stage power conversion; in the system, a power carrier (PLC) or a wireless (Wireless) communication module can be added between the optimizer and the inverter for communication, that is, a weak signal communication mode is adopted, and the transmission distance is relatively short. The communication robustness is also easily interfered by the power conversion noise and the surrounding environment noise in the system, and the special communication module also makes the system have higher communication cost. Alternatively, the optimizer has a Buck-Boost DC-DC power conversion circuit, and the inverter uses only DC-AC single-stage power conversion; since the MPPT and the configuration DC-AC input voltage function are implemented by the optimizer, the optimizer and the inverse There must be a communication function module that can transmit sampling data and status information in real time between the transformers. Therefore, it is necessary to use a power carrier (PLC) or a wireless (weak) weak signal communication mode to communicate between the optimizer and the inverter. There is also a defect that the transmission distance is short and the communication robustness is easily interfered by the power conversion noise and the surrounding environment noise in the system, and the communication cost is high.

Summary of the invention

According to a first aspect of the present application, there is provided an optimizer comprising a positive branch, a negative branch, a first voltage sensor, a first capacitor, a second voltage sensor, a second capacitor, an optimizer switch, an optimizer controller And a current sensor module; the optimizer controller is communicatively coupled to the optimizer switch; the current sensor module is a third current sensor, and the first voltage sensor is sequentially connected in parallel between the positive branch and the negative branch a first capacitor, a second voltage sensor, and a second capacitor; the optimizer switch is disposed on a positive branch between the first capacitor and the second voltage sensor; the third current sensor is disposed on the a first voltage sensor or a negative path between the first capacitor and the second voltage sensor or the second capacitor.

Or the current sensor module is a first current sensor and a second current sensor, and the first voltage sensor, the first capacitor, the second capacitor, and the second voltage sensor are sequentially connected in parallel between the positive branch and the negative branch The first current sensor is disposed on a positive branch between the positive input of the optimizer and the optimizer switch.

The optimizer switch is disposed on a positive branch between the first capacitor and the second capacitor; the second current sensor is disposed at a positive pole between the optimizer switch and the optimizer output On the road.

According to a second aspect, a photovoltaic power generation system includes a photovoltaic string unit, an inverter, a wake-up power supply, and a wake-up switch; the photovoltaic string unit leads to a positive transmission line and a negative transmission line, the positive transmission line and the a negative transmission line is introduced from an input end of the inverter and taken out from an output end of the inverter; the wake-up power supply is connected in parallel with the inverter; the wake-up switch is disposed on the wake-up power supply and the inverse Parallel branch of the transformer.

According to a third aspect, there is provided a photovoltaic power generation control method applied to the above photovoltaic power generation system, comprising the following process:

An optimizer switch that controls the optimizer is placed in an off state;

Controlling that the inverter is ready for grid connection, closing the wake-up switch, so that the wake-up switch provides an initial start-up identification voltage for the optimizer;

Detecting the initial starting identification voltage, and determining whether the initial starting identification voltage meets a predetermined condition;

In the case where it is judged that the initial startup identification voltage meets a predetermined condition, the optimizer switch that controls the optimizer is placed in an on state.

By adopting the technical scheme of the invention, in the photovoltaic power generation system, the state recognition communication is realized between the inverter and the optimizer by using a strong signal, which overcomes the short transmission distance of the weak electric signal communication in the prior art, and the communication robustness is easily affected by the system. The shortcomings of medium power conversion noise and ambient noise interference and high communication cost can eliminate the special weak signal communication module between the optimizer and the optimizer and between the optimizer and the inverter, which can significantly reduce the distributed photovoltaic power generation system. Communication costs.

DRAWINGS

1 is a schematic structural view of an optimizer of Embodiment 1;

2 is a schematic structural diagram of an optimizer of Embodiment 2;

3 is a schematic structural view of a photovoltaic power generation system according to Embodiment 3;

4 is a flow chart of a photovoltaic power generation control method according to Embodiment 3;

5 is a flow chart of a photovoltaic power generation control method according to Embodiment 3;

6 is a flow chart of a photovoltaic power generation control method according to a third embodiment.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings. Similar elements in different embodiments employ associated similar component numbers. In the following embodiments, many of the details are described in order to provide a better understanding of the application. However, those skilled in the art can easily realize that some of the features may be omitted in different situations, or may be replaced by other components, materials, and methods. In some cases, some operations related to the present application have not been shown or described in the specification, in order to avoid that the core portion of the present application is overwhelmed by excessive description, and those skilled in the art will describe these in detail. Related operations are not necessary, they can fully understand the relevant operations according to the description in the manual and the general technical knowledge in the field.

In addition, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can also be sequentially changed or adjusted in a manner that can be apparent to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of describing a particular embodiment, and are not intended to

The serial numbers themselves for the components herein, such as "first", "second", etc., are only used to distinguish the described objects, and do not have any order or technical meaning. As used herein, "connected" or "coupled", unless otherwise specified, includes both direct and indirect connections (joining).

Embodiment 1:

As shown in FIG. 1 , the optimizer 10 of the present embodiment includes a positive branch 101 , a negative branch 102 , a first voltage sensor 131 , a first capacitor 151 , a second voltage sensor 132 , a second capacitor 152 , and a bypass. A diode 16, an optimizer switch 12 (SW_optimizer), an optimizer controller 11, and a third current sensor 143.

The optimizer controller 11 is communicatively coupled to the optimizer switch 12, and may be in communication mode such as wire or wireless. The operating state of the optimizer switch 12 is controlled by the optimizer controller 11 to issue control commands.

The first voltage sensor 131, the first capacitor 151, the second voltage sensor 132, the second capacitor 152, and the bypass diode 16 are sequentially connected in parallel between the positive electrode branch 101 and the negative electrode branch 101. The optimizer switch 12 is disposed on the first capacitor 151. On the positive branch 101 between the second voltage sensor 132 and the second voltage sensor 132.

The third current sensor 143 is disposed on the negative branch 102 between the first capacitor 151 and the second voltage sensor 132. In other embodiments of the present invention, the third current sensor may be disposed on the negative branch between the first capacitor and the second capacitor according to actual design requirements; or, the first voltage sensor and the first voltage sensor a negative branch between the two voltage sensors; or a negative branch disposed between the first voltage sensor and the second capacitor.

The optimizer switch 12 can be composed of at least one mechanical switch or electronic switch (such as a triode, a field effect transistor, a thyristor, a relay, etc.), or can be a DC-DC power converter (such as Buck, Boost, Buck-Boost, etc.). ) constitutes.

The voltage sensor can be realized by a resistor voltage division method or a voltage sensing chip. The current sensor can be implemented by a combination of a resistor and an operational amplifier, or a dedicated current detecting chip, or a Hall sensor or a current detecting transformer.

Since the voltage of the photovoltaic panel varies with the current in the photovoltaic power generation system, when the optimizer switch is in the on/off state, if the first capacitor is not set in the optimizer, the voltage of the photovoltaic panel will continuously jump. The function of adding the first capacitor is to smooth the voltage of the photovoltaic panel. Similarly, the second capacitor also smoothes the ripple voltage of the optimizer switch output.

Embodiment 2:

As shown in FIG. 2, the optimizer 100 of the present embodiment includes a positive branch 101, a negative branch 102, a first voltage sensor 131, a first capacitor 151, a second capacitor 152, a second voltage sensor 132, and a bypass. The diode 16, the optimizer switch 12, the optimizer controller 11, and the first current sensor 141 and the second current sensor 142.

The optimizer controller 11 is communicatively coupled to the optimizer switch 12; the first voltage sensor 131, the first capacitor 151, the second capacitor 152, the second voltage sensor 132, and the bypass are sequentially connected in parallel between the positive branch 101 and the negative branch 102. The first current sensor 141 is disposed on the positive input terminal of the optimizer and the positive branch 101 of the optimizer switch 12 (specifically, for example, between the optimizer positive input terminal and the first voltage sensor 131, or the first voltage sensor) Between 131 and the first capacitor 151, or between the first capacitor 151 and the optimizer switch 12; the optimizer switch 12 is disposed between the first capacitor 151 and the second capacitor 152 The second current sensor 142 is disposed on the positive branch 101 between the optimizer switch 12 and the positive output of the optimizer (specifically, for example, between the optimizer switch 12 and the second capacitor 152, or the second capacitor 152) Between the second voltage sensor 132, or the second voltage sensor 132 and the bypass diode 16, or the positive branch 101 between the bypass diode 16 and the optimizer positive output terminal).

Other technical features of the optimizer of this embodiment are the same as those of the first embodiment, and therefore will not be described again.

Embodiment 3:

As shown in FIG. 3, the distributed photovoltaic power generation system of the present embodiment includes a photovoltaic string unit 01, a photovoltaic inverter 02 (Solar/PV Inverter), a wake-up power supply 03 (Start-up Source), and a wake-up switch 04 (SW_start). ).

The photovoltaic string unit 01 leads the positive transmission line 011 and the negative transmission line 012. The positive transmission line 011 and the negative transmission line 012 are introduced from the input of the inverter 02 and are taken out from the output of the inverter 02, thereby being connected to the grid.

The wake-up power supply 03 is connected in parallel with the inverter 02; the wake-up switch 04 is disposed on the parallel branch of the wake-up power supply 03 and the inverter 02.

Specifically, the power supply positive line 031 drawn from the input terminal of the wake-up power supply 03 is connected to the positive transmission line 011 on the input side of the inverter 02, and the power supply positive line 033 drawn from the output end of the wake-up power supply 03 is connected to the inverter. 02 The positive transmission line 011 on the output side; the power supply negative line 032 drawn from the input end of the wake-up power supply 03 is connected to the negative transmission line 012 on the input side of the inverter 02, and the power source that wakes up the power supply 03 from its output terminal The negative line 034 is connected to the negative transmission line 012 on the output side of the inverter 02.

The wake-up power supply 03 can be a separately configured power supply, such as an adapter, a power supply module, etc., or can be part of the inverter auxiliary power supply (one voltage output in the auxiliary power supply multiple output), and can also be based on actual design conditions by those skilled in the art. Use other power solutions.

The wake-up switch 04 is disposed on the power supply positive line 031 drawn from its input terminal by the wake-up power supply 03, and may be configured by at least one mechanical switch or electronic switch (such as a triode, a field effect transistor, a thyristor, a relay, etc.).

The photovoltaic string unit 01 is composed of a plurality of sets of photovoltaic panels (PV Panels) and an optimizer (Optimizer); each set of photovoltaic panels and the optimizer are in a series relationship, and the optimizer adopts an optimizer as protected by the first embodiment or the second embodiment. . The positive branch of one side of the positive input end of each optimizer is connected to the positive output end of the corresponding photovoltaic panel; the negative branch of one side of the negative input end of each optimizer is connected to the negative output end of the corresponding photovoltaic panel. Those skilled in the art should understand that the photovoltaic panel can be replaced by a photovoltaic array, a photovoltaic string (PV String) or a photovoltaic cell (V Battery), a photovoltaic panel.

In the photovoltaic string unit 01, the positive electrode branch is taken as the positive electrode transmission line, and the negative electrode branch is taken as the negative electrode transmission line.

Specifically, the plurality of sets of photovoltaic panels and optimizers in the photovoltaic unit 01 include a first photovoltaic panel 20, a first optimizer 10, a second photovoltaic panel, a second optimizer, an Nth photovoltaic panel 020, and an Nth optimizer 010.

The positive branch 101 on the positive output side of the first optimizer 10 is taken as the positive transmission line 011, and the positive branch 101 on the positive input side is connected to the positive output of the first photovoltaic panel 20, and the negative input is The negative side branch 102 of the side is connected to the negative output end of the first photovoltaic panel, the negative side branch 102 of the negative output side is connected to the positive output end of the second optimizer; the positive side of the positive input side of the second optimizer The branch is connected to the positive output end of the second photovoltaic panel, the negative branch of the negative input side is connected to the negative output of the second photovoltaic panel, and the negative branch of the negative output side is connected to the third optimizer The anode output of the positive input end of the Nth optimizer 010 is connected to the positive output terminal of the Nth photovoltaic panel 020, and the negative branch of the negative input side is connected to the Nth photovoltaic panel 020. The negative output terminal and the negative electrode side of the negative output end are taken as the negative transmission line 012; wherein N is greater than or equal to 1.

As shown in FIG. 4, the method for performing photovoltaic power generation control using the photovoltaic power generation system of the present embodiment is as follows:

St1, after the optimizer is powered on, the optimizer switch is placed in the off state by the optimizer controller, thereby implementing the boot safe mode function;

St2. Before the inverter is ready for grid connection, the control module of the inverter controls the wake-up switch to be in the off state; after the inverter is ready for grid connection, the wake-up switch is closed, so that the wake-up power supply is provided for the second capacitor of the optimizer. Initial starting identification voltage;

St3, the second voltage sensor detects an initial starting identification voltage;

Regarding the value of the initial starting identification voltage, the selection is based on the maximum input voltage that does not exceed the allowable operation of the inverter. Generally, in order to simplify the design, it is selected as a voltage value lower than the lower limit of the operating voltage of the inverter;

St4, the optimizer controller determines whether the initial startup identification voltage is maintained for a preset time (for example, no longer than 2 hours);

When the optimizer controller determines that the initial startup identification voltage has been maintained for a preset time, enter St5;

In the case that it is determined that the initial startup identification voltage fails to maintain the preset time, the step St3 is continued; in other embodiments, the power generation process may be stopped if it is determined that the initial startup identification voltage fails to maintain the preset time;

St5, the optimizer controller controls the optimizer switch to be placed in a closed conduction state, thereby achieving a safe wake-up of the photovoltaic power generation system;

St6, for photovoltaic power generation.

It can be seen from the above process that the main power energy flow of the photovoltaic power generation system is: photovoltaic panel→optimizer→inverter→grid, and the maximum power tracking of the photovoltaic string unit is performed by the inverter. The role of the photovoltaic panel is to convert the solar energy of the solar sun into DC power; the role of the inverter is to track and maximize the DC power output of the photovoltaic string unit and to invert the DC power into AC power for integration into the grid; The function of the device is to turn on or off the energy channel between the photovoltaic string unit and the inverter, and convert the DC electrical parameters (such as voltage and current values) outputted by the photovoltaic string unit into an effective range that the inverter can receive. .

The design of the St1 step is mainly to consider the safety of the installer during the installation operation. If the optimizer switch is not fully open after the optimizer is powered on, and there is no switch in the photovoltaic panel, the installer is in danger of being shocked. It is required to output the power of the photovoltaic panel after the photovoltaic panel and inverter installation are completed and the two are successfully connected.

As shown in FIG. 5, in other embodiments of the present invention, the following process may also be added:

St7. When the optimizer of the first embodiment is used, the current of the power transmission channel of the optimizer is detected by using the third current sensor (when the optimizer of the second embodiment is used, the first current sensor and the second current sensor respectively detect the branch Circuit current, the optimizer controller calculates the current of the optimizer power transmission channel according to the detection results of the two current sensors);

The optimizer controller determines whether the current meets a predetermined condition; specifically, the optimizer controller determines whether the current is reduced below a preset current value;

In the case of judging that the current is lower than the preset current value, enter St8;

In the case that it is judged that the current is not lower than the preset value, then St6 is continued;

St8, the optimizer controller controls the optimizer switch to be placed in the off state.

The current of the optimizer power transmission channel is lower than the preset current value. This indicates that the photovoltaic string power generation power is lower than the preset power value or an abnormal working state occurs, and the inverter needs to stop the grid-connected power generation, thereby achieving a very low power state. Inverter abnormality and fast shutdown function in the state of grid abnormality.

In the morning and evening, when the light is weak, there may be a very low power state. The abnormality of the inverter includes inverter damage, inverter over temperature protection, inverter short circuit over voltage protection, inverter input over voltage, etc. The abnormal state of the power grid includes the power grid power failure, the grid voltage is too high, and the grid voltage is too low.

As shown in FIG. 6, in other embodiments of the present invention, the following process may also be added:

St9, detecting, by the first voltage sensor, a first voltage of the bus bar of the optimizer input (the voltage of the photovoltaic cell panel, that is, an input voltage of the optimizer), and detecting a second voltage of the bus bar of the optimizer output by the second voltage sensor (optimizer) The output voltage) detects the current of the optimizer power transmission channel through the third current sensor (when the optimizer of the second embodiment is used, the branch current is respectively detected by the first current sensor and the second current sensor, and the optimizer controller according to The detection result of the two current sensors calculates the current of the optimizer power transmission channel);

Comparing the current of the first voltage, the second voltage, and the optimizer power transmission channel with a predetermined electrical characteristic of the arcing state (voltage/current characteristic);

If the current of the first voltage and the second voltage optimizer power transmission channel is consistent with the predetermined arcing state electrical characteristic, then enter St10;

If the first voltage, the second voltage, and the current of the optimizer power transmission channel do not match the electrical characteristics of the preset arcing state, continue St6;

St10, the optimizer's optimizer switch is placed in the off state, thus implementing the arc-switching function.

In the arc state, the output current of the optimizer will exhibit a waveform in the form of a pulsation, and the voltage of the optimizer will also have a large ripple. Therefore, the present embodiment determines whether the system has a pull arc by monitoring the voltage/current characteristics, and judges the pull. Turn off the optimizer's power output in the presence of an arc.

In other embodiments of the present invention, the above process may also be designed as a complete process. The detailed steps are described above, and therefore will not be described again.

In a further optimized embodiment, at least one Bypass diode is connected between the positive and negative output busbars of the optimizer, when the corresponding photovoltaic panel or optimizer fails internally, or the photovoltaic panel is shaded and cannot be When the power is output, the bypass diode acts as a freewheeling function, enabling bypass function and power optimization.

In the circuit of the photovoltaic power generation system of the embodiment, the output of the optimizer is connected in parallel with the bypass diode. When the optimizer operates under the condition of normal power output, the output voltage is greater than the bypass diode forward voltage, bypass. The diode is in the off state. In a distributed usage scenario, multiple photovoltaic panels are serially stringed (each panel is configured with its own optimizer) to output power to the inverter. When the optimizer has no power output, the optimizer's output voltage is 0, due to this The optimizer output is in series with the other panel optimizer outputs, while the output voltages of the other optimizers provide a forward bias voltage to turn on the bypass diode of the optimizer's no-voltage output for bypass bypass .

The photovoltaic power generation system and the photovoltaic power generation control method of the invention adopt a strong signal to realize state recognition communication between the inverter and the optimizer, and overcome the short transmission distance of the weak electric signal communication in the prior art, and the communication robustness is easily affected by the system. The disadvantages of power conversion noise and ambient noise interference and high communication cost can eliminate the special weak signal communication module between the optimizer and the optimizer and between the optimizer and the inverter, which can significantly reduce the distributed photovoltaic power generation system. Communication costs.

The design of the wake-up power supply and wake-up switch, as well as the detection scheme for the initial start-up identification voltage, achieve low-cost, long-distance, stable and reliable communication between the inverter and the optimizer, and perform system wake-up well ( Wake Up, Start Up) function.

By monitoring the current/voltage magnitude and dynamic variation characteristics in the optimizer, it is possible to identify the abnormal state of the inverter and the arcing state of the system, and perform the Shutdown and Shut-off functions; The bypass diode is added between the bus bars to further realize the output power optimization function of the photovoltaic string.

The invention has been described above with reference to specific examples, which are merely intended to aid the understanding of the invention and are not intended to limit the invention. For the person skilled in the art to which the invention pertains, several simple derivations, variations or substitutions can be made in accordance with the inventive concept.

Claims

An optimizer characterized in that

The positive branch (101), the negative branch (102), the first voltage sensor (131), the first capacitor (151), the second voltage sensor (132), the second capacitor (152), and the optimizer switch (12) ), an optimizer controller (11) and a current sensor module;

The optimizer controller is communicatively coupled to the optimizer switch;

The current sensor module is a third current sensor (143), and the first voltage sensor, the first capacitor, the second voltage sensor, and the second capacitor are sequentially connected in parallel between the positive branch and the negative branch;

The optimizer switch is disposed on a positive branch of the first capacitor and the second voltage sensor;

The third current sensor is disposed on the negative pole of the first voltage sensor or the first capacitor and the second voltage sensor or the second capacitor;

Alternatively, the current sensor module is a first current sensor (141) and a second current sensor (142), and the first voltage sensor, the first capacitor, and the second are sequentially connected in parallel between the positive branch and the negative branch a capacitor and a second voltage sensor;

The first current sensor is disposed on a positive branch of the optimizer input terminal and the optimizer switch;

The optimizer switch is disposed on a positive branch of the first capacitor and the second capacitor;

The second current sensor is disposed on a positive branch between the optimizer switch and the optimizer output.
The optimizer of claim 1 wherein:

Also including at least one bypass diode (16);

The bypass diode is connected in parallel between the positive branch and the negative branch of the optimizer output.
A photovoltaic power generation system, characterized in that

Including photovoltaic string unit (01), inverter (02), wake-up power supply (03) and wake-up switch (04);

The photovoltaic string unit leads to a positive transmission line (011) and a negative transmission line (012), the positive transmission line and the negative transmission line being introduced by an input of the inverter and output from the inverter Lead out

The wake-up power source is connected in parallel with the inverter;

The wake-up switch is disposed on the parallel branch of the wake-up power source and the inverter.
The system of claim 3 wherein:

The power supply positive line (031) drawn from its input terminal is connected to the positive transmission line on the input side of the inverter, and the power supply positive line (033) from the output terminal of the wake-up power supply is connected to a positive transmission line on one side of the output end of the inverter;

The power supply negative line (032) drawn from its input terminal is connected to the negative transmission line on the input side of the inverter, and the power supply negative line (034) from the output terminal of the wake-up power supply is connected to a negative transmission line on one side of the output end of the inverter;

The wake-up switch is disposed on a positive line of the power source that is pulled from the input end of the wake-up power source;

The photovoltaic string unit includes at least one set of photovoltaic panels (20) and an optimizer (10);

The optimizer adopts the optimizer according to claim 1 or 2;

In the at least one set of photovoltaic panels and optimizers, each set of photovoltaic panels and the optimizer are in a series relationship;

a positive branch of one side of the optimizer input end is connected to a positive output end of the photovoltaic panel;

a negative branch of one side of the optimizer input end is connected to a negative output end of the photovoltaic panel;

In the photovoltaic string unit, the positive electrode branch is taken as a positive electrode transmission line, and the negative electrode branch is taken as a negative electrode transmission line.
The system of claim 4 wherein:

The at least one set of photovoltaic panels and optimizers includes a first photovoltaic panel, a first optimizer, a second photovoltaic panel, a second optimizer, an Nth photovoltaic panel, an Nth optimizer;

The positive branch of the output side of the first optimizer is taken as a positive transmission line, and the positive branch of the input end side is connected to the positive output end of the first photovoltaic panel, and the negative side of the input end side thereof The circuit is connected to the negative output end of the first photovoltaic panel, and the negative electrode side of the output end is connected to the positive output end of the second optimizer;

a positive branch of one side of the input end of the second optimizer is connected to a positive output end of the second photovoltaic panel, and a negative branch of one side of the input end is connected to a negative output end of the second photovoltaic panel, a negative branch on one side of the output is connected to an output of the third optimizer;

......

a positive branch of one side of the input end of the Nth optimizer is connected to a positive output end of the Nth photovoltaic panel, and a negative branch of one side of the input end is connected to a negative output end of the Nth photovoltaic panel, The negative branch on the output side is taken as the negative transmission line;

Where N is greater than or equal to 1.
A system according to claim 4 or 5, wherein

The inverter is configured to control the wake-up switch to be closed after the grid is ready, so that the wake-up switch provides an initial start identification voltage for the optimizer;

The optimizer controller is configured to control the first voltage sensor or the second voltage sensor to detect the initial startup identification voltage, determine whether the initial startup identification voltage meets a predetermined condition, and determine that the initial startup identification voltage meets In the case of a predetermined condition, the optimizer switch that controls the optimizer is placed in an on state.
The system of claim 6 wherein:

The optimizer controller is further configured to control a current sensor disposed therein to detect a current of the power transmission channel of the optimizer, and determine whether the current meets a predetermined condition;

In the case where it is judged that the current does not satisfy the predetermined condition, the optimizer switch that controls the optimizer is placed in the off state.
The system of claim 6 wherein:

The optimizer controller is further configured to control the first voltage sensor, the second voltage sensor, and/or a current sensor disposed therein to respectively detect a first voltage of an input bus of the optimizer, the optimization a second voltage of the output bus of the device and/or a current of the optimizer power transmission channel;

Comparing the first voltage, the second voltage, and/or the current of the optimizer power transmission channel with a predetermined arcing state electrical characteristic;

And if the current of the first voltage, the second voltage, and/or the optimizer power transmission channel is consistent with a preset arcing state electrical characteristic, the optimizer switch that controls the optimizer is placed off Open state.
A photovoltaic power generation control method, which is applied to the photovoltaic power generation system according to any one of claims 3 to 7, which comprises:

An optimizer switch that controls the optimizer is placed in an off state;

Controlling that the inverter is ready for grid connection, closing the wake-up switch, so that the wake-up switch provides an initial start-up identification voltage for the optimizer;

Detecting the initial starting identification voltage, and determining whether the initial starting identification voltage meets a predetermined condition;

In the case where it is judged that the initial startup identification voltage meets a predetermined condition, the optimizer switch that controls the optimizer is placed in an on state.
The method of claim 9 wherein:

Also includes:

Detecting a current of a power transmission channel of the optimizer, and determining whether the current meets a predetermined condition;

In the case of judging that the current does not meet the predetermined condition, the optimizer switch that controls the optimizer is placed in an off state;

And/or, also includes:

Detecting a first voltage of an input bus of the optimizer, a second voltage of an output bus of the optimizer, and/or a current of the optimizer power transmission channel;

Comparing the first voltage, the second voltage, and/or the current of the optimizer power transmission channel with a predetermined arcing state electrical characteristic;

And if the current of the first voltage, the second voltage, and/or the optimizer power transmission channel is consistent with a preset arcing state electrical characteristic, the optimizer switch that controls the optimizer is placed off Open state.