阅读说明：本技术 光伏系统pid效应修复方法、装置和光伏系统 (Photovoltaic system PID effect repairing method and device and photovoltaic system ) 是由 黄猛 郭泳颖 姜颖异 黄颂儒 刘小高 付鹏亮 于 2020-07-27 设计创作，主要内容包括：本申请涉及一种光伏系统PID效应修复方法、装置和光伏系统,该方法包括：接收类型配置参数；当根据类型配置参数判断光伏系统的光伏组件为P型光伏组件时,输出第一类控制指令至电压抬升电路；第一类控制指令用于控制电压抬升电路对接入的交流电进行处理,输出直流正压至光伏组件的负极；当根据类型配置参数判断光伏系统的光伏组件为N型光伏组件时,输出第二类控制指令至电压抬升电路；第二类控制指令用于控制电压抬升电路对接入的交流电进行处理,输出直流负压至光伏组件的负极。通过根据光伏系统的光伏组件类型对应调节电压抬升电路的输出电压,从而针对不同类型的光伏组件都可进行PID效应修复,提高了对光伏系统的兼容性。(The application relates to a photovoltaic system PID effect repairing method, a photovoltaic system PID effect repairing device and a photovoltaic system, wherein the method comprises the following steps: receiving type configuration parameters; when the photovoltaic module of the photovoltaic system is judged to be a P-type photovoltaic module according to the type configuration parameters, outputting a first type of control instruction to the voltage lifting circuit; the first type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct current positive voltage to the negative electrode of the photovoltaic module; when the photovoltaic module of the photovoltaic system is judged to be an N-type photovoltaic module according to the type configuration parameters, outputting a second type of control instruction to the voltage lifting circuit; the second type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct current negative voltage to the negative electrode of the photovoltaic module. The output voltage of the voltage boost circuit is correspondingly adjusted according to the type of the photovoltaic assembly of the photovoltaic system, so that PID effect repair can be carried out on the photovoltaic assemblies of different types, and the compatibility of the photovoltaic system is improved.)

1. A photovoltaic system PID effect repairing method is characterized by comprising the following steps:

receiving type configuration parameters;

when the photovoltaic module of the photovoltaic system is judged to be a P-type photovoltaic module according to the type configuration parameters, outputting a first type of control instruction to the voltage lifting circuit; the voltage lifting circuit is connected with the negative electrode of the photovoltaic assembly, and the first type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct-current positive voltage to the negative electrode of the photovoltaic assembly;

when the photovoltaic module of the photovoltaic system is judged to be an N-type photovoltaic module according to the type configuration parameters, outputting a second type of control instruction to the voltage lifting circuit; the second type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct current negative voltage to the negative electrode of the photovoltaic module.

2. The method for photovoltaic system PID effect recovery according to claim 1, wherein the outputting the first type of control command to the voltage boost circuit or the outputting the second type of control command to the voltage boost circuit comprises: and outputting the PWM signal to a control end of the voltage lifting circuit corresponding to the switch unit.

3. The method for photovoltaic system PID effect restoration according to claim 1, wherein after outputting the first type of control command to the voltage boost circuit or outputting the second type of control command to the voltage boost circuit, the method further comprises:

receiving the voltage transmitted to the sampling voltage by the voltage sensor; the sampling voltage is obtained by sampling the output voltage of the voltage lifting circuit by the voltage sensor;

and when the voltage lifting circuit is judged to be short-circuited according to the sampling voltage, stopping conveying the alternating current to the voltage lifting circuit.

4. The photovoltaic system PID effect recovery method of claim 3, wherein after the receiving voltage sensor transmits the sampling voltage, the method further comprises:

and when the lifting voltage is detected to be in an opposite phase according to the sampling voltage and the type configuration parameters, adjusting the output control instruction so as to adjust the lifting voltage.

5. A photovoltaic system PID effect repair device, comprising:

the parameter receiving module is used for receiving the type configuration parameters;

the positive voltage lifting module is used for outputting a first type of control instruction to the voltage lifting circuit when the photovoltaic module of the photovoltaic system is judged to be a P type photovoltaic module according to the type configuration parameters; the voltage lifting circuit is connected with the negative electrode of a photovoltaic assembly in the photovoltaic system, and the first type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct-current positive voltage to the negative electrode of the photovoltaic assembly;

the negative pressure lifting module is used for outputting a second type of control instruction to the voltage lifting circuit when the photovoltaic module of the photovoltaic system is judged to be the N type photovoltaic module according to the type configuration parameters; the second type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct current negative voltage to the negative electrode of the photovoltaic module.

6. A photovoltaic system, comprising a controller, a voltage boost circuit and a photovoltaic module, wherein the controller is connected with the voltage boost circuit, the voltage boost circuit is connected with the negative electrode of the photovoltaic module, and the controller performs PID effect repair of the photovoltaic system according to the method of any one of claims 1 to 4.

7. The photovoltaic system of claim 6, further comprising a transformer, a primary winding of the transformer being connected to an AC power grid, a secondary winding of the transformer being connected to the voltage boost circuit.

8. The photovoltaic system of claim 7, wherein the voltage boost circuit comprises a first boost circuit, a second boost circuit, and a ground resistor, the first boost circuit connecting the secondary winding of the transformer, the controller, and the negative terminal of the photovoltaic module, the second boost circuit connecting the secondary winding of the transformer, the controller, and the first boost circuit and being grounded through the ground resistor.

9. The photovoltaic system of claim 8, wherein the first boost circuit comprises a switch unit IGBT1, a switch unit IGBT2, a switch unit IGBT5, and a switch unit IGBT6, wherein a control terminal of the switch unit IGBT1, a control terminal of the switch unit IGBT2, a control terminal of the switch unit IGBT5, and a control terminal of the switch unit IGBT6 are all connected to the controller, an input terminal of the switch unit IGBT1 is connected to an input terminal of the switch unit IGBT5, an output terminal of the switch unit IGBT1 is connected to an output terminal of the switch unit IGBT2, and an input terminal of the switch unit IGBT2 is connected to the first terminal of the secondary winding of the transformer; the input end of the switch unit IGBT5 is connected with the negative electrode of the photovoltaic module, the output end of the switch unit IGBT5 is connected with the output end of the switch unit IGBT6, and the input end of the switch unit IGBT6 is connected with the second end of the secondary winding of the transformer;

the second lifting circuit comprises a switch unit IGBT3, a switch unit IGBT4, a switch unit IGBT7 and a switch unit IGBT8, wherein a control end of the switch unit IGBT3, a control end of the switch unit IGBT4, a control end of the switch unit IGBT7 and a control end of the switch unit IGBT8 are all connected with the controller, an input end of the switch unit IGBT3 is connected with a first end of a secondary winding of the transformer, an output end of the switch unit IGBT3 is connected with an output end of the switch unit IGBT4, an input end of the switch unit IGBT4 is connected with a first end of the grounding resistor, and a second end of the grounding resistor is grounded; the input end of the switch unit IGBT7 is connected with the second end of the secondary winding of the transformer, the output end of the switch unit IGBT7 is connected with the output end of the switch unit IGBT8, and the input end of the switch unit IGBT8 is connected with the first end of the ground resistor; wherein each switching unit freewheels through a freewheeling diode when turned off.

10. The photovoltaic system of claim 8, wherein the voltage boost circuit further comprises a voltage sensor, a capacitor and a control switch, wherein the voltage sensor and the capacitor are connected in parallel, and then one end of the voltage sensor is connected with the first boost circuit, and the other end of the voltage sensor is connected with the second boost circuit; and the secondary winding of the transformer is connected with the first lifting circuit and the second lifting circuit through the control switch.

Technical Field

The application relates to the technical field of power electronics, in particular to a photovoltaic system PID effect repairing method and device and a photovoltaic system.

Background

The high-voltage photovoltaic system can cause the photovoltaic unit to bear higher positive bias or negative bias to the ground, and particularly under special conditions of high temperature, high humidity and the like, a photovoltaic module in the photovoltaic unit can generate a serious PID (Potential induced degradation) effect, so that the open-circuit voltage, the short-circuit current, the fill factor of the photovoltaic unit are reduced, and the power generation amount of the photovoltaic system is gradually reduced.

The traditional PID effect repairing mode of the photovoltaic system is to positively lift the negative electrode of the photovoltaic unit to the ground potential, so that the PID effect of the photovoltaic unit is repaired. However, this method can only be applied to a photovoltaic system using P-type photovoltaic cells, but is not applicable to a photovoltaic system using N-type photovoltaic cells, and has poor compatibility with the photovoltaic system.

Disclosure of Invention

Therefore, it is necessary to provide a photovoltaic system PID effect repairing method, device and photovoltaic system aiming at the problem of poor compatibility of the conventional photovoltaic system PID effect repairing method to the photovoltaic system, so as to achieve the technical effect of improving the compatibility of the photovoltaic system.

A photovoltaic system PID effect repairing method comprises the following steps:

receiving type configuration parameters;

when the photovoltaic module of the photovoltaic system is judged to be a P-type photovoltaic module according to the type configuration parameters, outputting a first type of control instruction to the voltage lifting circuit; the voltage lifting circuit is connected with the negative electrode of the photovoltaic assembly, and the first type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct-current positive voltage to the negative electrode of the photovoltaic assembly;

when the photovoltaic module of the photovoltaic system is judged to be an N-type photovoltaic module according to the type configuration parameters, outputting a second type of control instruction to the voltage lifting circuit; the second type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct current negative voltage to the negative electrode of the photovoltaic module.

In one embodiment, the outputting the first type of control command to the voltage boost circuit or the outputting the second type of control command to the voltage boost circuit includes: and outputting a PWM (Pulse Width Modulation) signal to a control end of the voltage lifting circuit corresponding to the switch unit.

In one embodiment, after outputting the first type of control command to the voltage boost circuit or outputting the second type of control command to the voltage boost circuit, the method further includes:

receiving the voltage transmitted to the sampling voltage by the voltage sensor; the sampling voltage is obtained by sampling the output voltage of the voltage lifting circuit by the voltage sensor;

and when the voltage lifting circuit is judged to be short-circuited according to the sampling voltage, stopping conveying the alternating current to the voltage lifting circuit.

In one embodiment, after the receiving voltage sensor transmits the sampling voltage, the method further includes:

and when the lifting voltage is detected to be in an opposite phase according to the sampling voltage and the type configuration parameters, adjusting the output control instruction so as to adjust the lifting voltage.

A photovoltaic system PID effect repair device, comprising:

the parameter receiving module is used for receiving the type configuration parameters;

the positive voltage lifting module is used for outputting a first type of control instruction to the voltage lifting circuit when the photovoltaic module of the photovoltaic system is judged to be a P type photovoltaic module according to the type configuration parameters; the voltage lifting circuit is connected with the negative electrode of a photovoltaic assembly in the photovoltaic system, and the first type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct-current positive voltage to the negative electrode of the photovoltaic assembly;

the negative pressure lifting module is used for outputting a second type of control instruction to the voltage lifting circuit when the photovoltaic module of the photovoltaic system is judged to be the N type photovoltaic module according to the type configuration parameters; the second type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct current negative voltage to the negative electrode of the photovoltaic module.

A photovoltaic system comprises a controller, a voltage lifting circuit and a photovoltaic assembly, wherein the controller is connected with the voltage lifting circuit, the voltage lifting circuit is connected with a negative electrode of the photovoltaic assembly, and the controller carries out PID effect restoration on the photovoltaic system according to the method.

In one embodiment, the photovoltaic system further comprises a transformer, a primary winding of the transformer is connected with an alternating current grid, and a secondary winding of the transformer is connected with the voltage raising circuit.

In one embodiment, the voltage boost circuit includes a first boost circuit, a second boost circuit and a ground resistor, the first boost circuit is connected to the secondary winding of the transformer, the controller and the negative electrode of the photovoltaic module, and the second boost circuit is connected to the secondary winding of the transformer, the controller and the first boost circuit and is grounded through the ground resistor.

In one embodiment, the first boost circuit comprises a switch unit IGBT2, a switch unit IGBT5, and a switch unit IGBT6, the control terminal of the switch unit IGBT1, the control terminal of the switch unit IGBT2, the control terminal of the switch unit IGBT5, and the control terminal of the switch unit IGBT6 are all connected to the controller, the input terminal of the switch unit IGBT1 is connected to the input terminal of the switch unit IGBT5, the output terminal of the switch unit IGBT1 is connected to the output terminal of the switch unit IGBT2, and the input terminal of the switch unit IGBT2 is connected to the first terminal of the secondary winding of the transformer; the input end of the switch unit IGBT5 is connected with the negative electrode of the photovoltaic module, the output end of the switch unit IGBT5 is connected with the output end of the switch unit IGBT6, and the input end of the switch unit IGBT6 is connected with the second end of the secondary winding of the transformer;

the second lifting circuit comprises a switch unit IGBT3, a switch unit IGBT4, a switch unit IGBT7 and a switch unit IGBT8, wherein a control end of the switch unit IGBT3, a control end of the switch unit IGBT4, a control end of the switch unit IGBT7 and a control end of the switch unit IGBT8 are all connected with the controller, an input end of the switch unit IGBT3 is connected with a first end of a secondary winding of the transformer, an output end of the switch unit IGBT3 is connected with an output end of the switch unit IGBT4, an input end of the switch unit IGBT4 is connected with a first end of the grounding resistor, and a second end of the grounding resistor is grounded; the input end of the switch unit IGBT7 is connected with the second end of the secondary winding of the transformer, the output end of the switch unit IGBT7 is connected with the output end of the switch unit IGBT8, and the input end of the switch unit IGBT8 is connected with the first end of the ground resistor; wherein each switching unit freewheels through a freewheeling diode when turned off.

In one embodiment, the voltage boost circuit further comprises a voltage sensor, a capacitor and a control switch, wherein after the voltage sensor and the capacitor are connected in parallel, one end of the voltage sensor is connected with the first boost circuit, and the other end of the voltage sensor is connected with the second boost circuit; and the secondary winding of the transformer is connected with the first lifting circuit and the second lifting circuit through the control switch.

According to the photovoltaic system PID effect repairing method, the photovoltaic system PID effect repairing device and the photovoltaic system, the type of a photovoltaic component of the photovoltaic system is analyzed according to the received type configuration parameters, when the photovoltaic component is a P-type photovoltaic component, a first type of control instruction is output to the voltage lifting circuit, the voltage lifting circuit is controlled to process the accessed alternating current, and the direct current positive voltage is output to the negative electrode of the photovoltaic component; when the photovoltaic module is an N-type photovoltaic module, a second type of control instruction is output to the voltage lifting circuit, the voltage lifting circuit is controlled to process the accessed alternating current, and direct current negative voltage is output to the negative electrode of the photovoltaic module. The output voltage of the voltage boosting circuit is correspondingly adjusted according to the type of the photovoltaic assembly of the photovoltaic system, so that PID effect repair can be carried out on the photovoltaic assemblies of different types, the reduction of the power generation capacity of the photovoltaic system caused by the PID effect is avoided, and the compatibility of the photovoltaic system is improved.

Drawings

FIG. 1 is a flow chart of a method for photovoltaic system PID effect restoration in one embodiment;

FIG. 2 is a flow chart of a method for photovoltaic system PID effect healing in another embodiment;

FIG. 3 is a block diagram of an embodiment of a photovoltaic system PID effect repair apparatus;

FIG. 4 is a block diagram of a PID effect repairing apparatus of a photovoltaic system according to another embodiment;

FIG. 5 is a schematic diagram of a photovoltaic system according to an embodiment;

fig. 6 is a schematic diagram illustrating PWM pulse and boost voltage simulation of a photovoltaic system according to an embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

In one embodiment, a method for repairing PID effects of a photovoltaic system is provided, as shown in fig. 1, including:

step S110: a type configuration parameter is received. The type configuration parameters can be received through the controller, so that the type of the photovoltaic assembly in the photovoltaic system can be known. The types of the photovoltaic modules comprise a P type and an N type, specifically, when a worker needs to perform a PID photovoltaic system on the photovoltaic system, the worker can input type configuration parameters to the controller by changing dial codes or adopting modes such as upper computer configuration and the like so as to be used as a basis for voltage lifting control in the following process.

Step S120: and when the photovoltaic module of the photovoltaic system is judged to be a P-type photovoltaic module according to the type configuration parameters, outputting a first type of control instruction to the voltage lifting circuit.

The voltage lifting circuit is connected with the negative electrode of the photovoltaic assembly, and the first type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct current positive voltage to the negative electrode of the photovoltaic assembly. Specifically, when a photovoltaic module of the photovoltaic system is a P-type photovoltaic module, the controller outputs a first type of control instruction to the voltage lifting circuit, adjusts the working mode of the voltage lifting circuit, controls the voltage lifting circuit to process the accessed alternating current, outputs direct-current positive voltage to the negative electrode of the photovoltaic module, and completes the PID effect repair of the P-type photovoltaic module.

Step S130: and when the photovoltaic module of the photovoltaic system is judged to be the N-type photovoltaic module according to the type configuration parameters, outputting a second type of control instruction to the voltage lifting circuit.

The second type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct current negative voltage to the negative electrode of the photovoltaic module. If the photovoltaic module of the photovoltaic system is an N-type photovoltaic module, the controller outputs a second type of control instruction to the voltage lifting circuit, the voltage lifting circuit is controlled to process the accessed alternating current, direct current negative voltage is output to the negative electrode of the photovoltaic module, and PID effect restoration of the N-type photovoltaic module is completed.

In one embodiment, the method of adjusting the voltage-boosting circuit by outputting the first type of control command and the second type of control command is not exclusive, and outputting the first type of control command to the voltage-boosting circuit or outputting the second type of control command to the voltage-boosting circuit includes: and outputting the PWM signal to a control end of the voltage lifting circuit corresponding to the switch unit. The controller can output PWM signals to the switch unit in the voltage lifting circuit through the corresponding port according to the type of the photovoltaic module, the on-off of the switch unit is controlled, and low level is maintained for the switch unit which does not need to work, so that the working mode of the voltage lifting circuit is adjusted, and direct-current positive voltage or direct-current negative voltage is output to the negative electrode of the photovoltaic module.

According to the PID effect repairing method of the photovoltaic system, the type of a photovoltaic component of the photovoltaic system is analyzed according to received type configuration parameters, when the photovoltaic component is a P-type photovoltaic component, a first type of control instruction is output to a voltage lifting circuit, the voltage lifting circuit is controlled to process the accessed alternating current, and direct-current positive voltage is output to the negative electrode of the photovoltaic component; when the photovoltaic module is an N-type photovoltaic module, a second type of control instruction is output to the voltage lifting circuit, the voltage lifting circuit is controlled to process the accessed alternating current, and direct current negative voltage is output to the negative electrode of the photovoltaic module. The output voltage of the voltage lifting circuit is adjusted correspondingly only according to the type of the photovoltaic assembly of the photovoltaic system, circuit structures do not need to be designed for the photovoltaic assemblies of different types respectively, device cost can be reduced, and power failure risks are reduced, so that PID effect repair can be performed for the photovoltaic assemblies of different types, the reduction of the power generation capacity of the photovoltaic system caused by the PID effect is avoided, and the compatibility of the photovoltaic system is improved.

In one embodiment, as shown in fig. 2, after outputting the first type of control command to the voltage boost circuit or outputting the second type of control command to the voltage boost circuit, the method further includes steps S140 and S150.

Step S140: the receiving voltage sensor transmits to the sampling voltage. The sampling voltage is obtained by sampling the output voltage of the voltage lifting circuit by the voltage sensor. The voltage sensor can be connected with the output end of the voltage lifting circuit, the output voltage of the voltage lifting circuit is collected, and the sampling voltage is obtained and sent to the controller.

Step S150: and when the voltage lifting circuit is judged to be short-circuited according to the sampling voltage, stopping transmitting the alternating current to the voltage lifting circuit. Specifically, the controller detects the failure of the voltage boost power supply according to the sampling point voltage, and when the sampling voltage is detected to be 0, the boost voltage is 0, and the boost circuit is short-circuited. At the moment, the alternating current is controlled to be stopped being transmitted to the voltage lifting circuit, and the lifting circuit stops running, so that the voltage lifting circuit is protected.

Further, in one embodiment, after step S140, with continued reference to fig. 2, the method further includes step S160: and when the lifting voltage is detected to be in an inverted state according to the sampling voltage and the type configuration parameters, adjusting the output control instruction so as to adjust the lifting voltage. Specifically, if the lifting voltage output by the voltage lifting circuit is detected not to correspond to the type of the photovoltaic module according to the sampling voltage and the type configuration parameters, the lifting voltage is inverted, and the controller adjusts the output control instruction to enable the lifting voltage to be adjusted to the correct voltage.

It should be understood that although the various steps in the flow charts of fig. 1-2 are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least some of the steps in fig. 1-2 may include multiple sub-steps or multiple stages that are not necessarily performed at the same time, but may be performed at different times, and the order of performance of the sub-steps or stages is not necessarily sequential, but may be performed in turn or alternating with other steps or at least some of the sub-steps or stages of other steps.

In one embodiment, a photovoltaic system PID effect repairing device is further provided, as shown in fig. 3, including a parameter receiving module 110, a positive pressure lifting module 120, and a negative pressure lifting module 130.

The parameter receiving module 110 is configured to receive a type configuration parameter; the positive voltage lifting module 120 is configured to output a first type of control instruction to the voltage lifting circuit when the photovoltaic module of the photovoltaic system is determined to be a P-type photovoltaic module according to the type configuration parameter; the voltage lifting circuit is connected with the negative electrode of a photovoltaic assembly in the photovoltaic system, and the first type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct current positive voltage to the negative electrode of the photovoltaic assembly; the negative-pressure lifting module 130 is configured to output a second type of control instruction to the voltage lifting circuit when the photovoltaic module of the photovoltaic system is determined to be an N-type photovoltaic module according to the type configuration parameter; the second type of control instruction is used for controlling the voltage lifting circuit to process the accessed alternating current and output direct current negative voltage to the negative electrode of the photovoltaic module.

In one embodiment, the positive voltage boost module 120 or the negative voltage boost module 130 outputs a PWM signal to a control terminal of a corresponding switch unit in the voltage boost circuit.

In one embodiment, as shown in FIG. 4, the apparatus further comprises a voltage detection module 140. The voltage detection module 140 is configured to receive the sampling voltage transmitted by the voltage sensor after the positive voltage boost module 120 outputs the first type of control instruction to the voltage boost circuit, or after the negative voltage boost module 130 outputs the second type of control instruction to the voltage boost circuit; and when the voltage lifting circuit is judged to be short-circuited according to the sampling voltage, stopping transmitting the alternating current to the voltage lifting circuit.

Further, in one embodiment, the voltage detection module 140 is further configured to adjust the output control command to adjust the boost voltage when the boost voltage is detected to be inverted according to the sampling voltage and the type configuration parameter.

For specific limitations of the photovoltaic system PID effect repairing apparatus, reference may be made to the above limitations of the photovoltaic system PID effect repairing method, which are not described herein again. All or part of each module in the photovoltaic system PID effect repairing device can be realized by software, hardware and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.

The PID effect repairing device of the photovoltaic system analyzes the type of a photovoltaic module of the photovoltaic system according to the received type configuration parameters, and when the photovoltaic module is a P-type photovoltaic module, a first type of control instruction is output to the voltage lifting circuit, the voltage lifting circuit is controlled to process the accessed alternating current, and direct-current positive voltage is output to the negative electrode of the photovoltaic module; when the photovoltaic module is an N-type photovoltaic module, a second type of control instruction is output to the voltage lifting circuit, the voltage lifting circuit is controlled to process the accessed alternating current, and direct current negative voltage is output to the negative electrode of the photovoltaic module. The output voltage of the voltage lifting circuit is adjusted correspondingly only according to the type of the photovoltaic assembly of the photovoltaic system, circuit structures do not need to be designed for the photovoltaic assemblies of different types respectively, device cost can be reduced, and power failure risks are reduced, so that PID effect repair can be performed for the photovoltaic assemblies of different types, the reduction of the power generation capacity of the photovoltaic system caused by the PID effect is avoided, and the compatibility of the photovoltaic system is improved.

In one embodiment, as shown in fig. 5, there is also provided a photovoltaic system, which includes a controller U1, a voltage boost circuit 200 and a photovoltaic module, wherein the controller U1 is connected to the voltage boost circuit 200, the voltage boost circuit 200 is connected to the negative PV-of the photovoltaic module, and the controller U1 performs PID effect repair of the photovoltaic system according to the method described above.

Specifically, the controller U1 analyzes the type of the photovoltaic module according to the type configuration parameters, outputs a PWM signal to a corresponding switch unit in the voltage boost circuit 200 through a port according to the type of the photovoltaic module, controls the switch unit to be turned on and off, and keeps the switch unit which does not need to operate at a low level, thereby setting the operation mode of the voltage boost circuit 200, so that the voltage boost circuit 200 processes the accessed alternating current and outputs a direct current positive voltage or a direct current negative voltage to the negative PV-of the photovoltaic module.

In the photovoltaic system, the controller U1 analyzes the type of the photovoltaic module according to the received type configuration parameters, and when the photovoltaic module is a P-type photovoltaic module, outputs a first type of control instruction to the voltage boost circuit 200, controls the voltage boost circuit 200 to process the accessed alternating current and outputs direct-current positive voltage to the negative electrode PV-of the photovoltaic module; when the photovoltaic module is an N-type photovoltaic module, a second type of control command is output to the voltage boost circuit 200, the voltage boost circuit 200 is controlled to process the accessed alternating current, and direct current negative voltage is output to the negative electrode PV-of the photovoltaic module. The output voltage of the voltage boost circuit 200 is adjusted according to the type of the photovoltaic module without designing circuit structures for the photovoltaic modules of different types, so that the device cost can be reduced, and the power failure risk can be reduced.

In one embodiment, the photovoltaic system further includes a transformer T1, the primary winding of the transformer T1 is connected to the ac power grid, and the secondary winding of the transformer T1 is connected to the voltage boost circuit 200. The ac output from the ac power grid may be reduced by the transformer T1 and then output to the voltage boost circuit 200, so that the voltage boost circuit 200 may process the received voltage to obtain a boosted voltage, and send the boosted voltage to the negative PV-of the photovoltaic module.

The specific structure of the voltage boost circuit 200 is not exclusive, and in one embodiment, with continued reference to fig. 5, the voltage boost circuit 200 includes a first boost circuit 210, a second boost circuit 220, and a ground resistor R1, the first boost circuit 210 connects the secondary winding of the transformer T1, the controller U1, and the negative pole PV of the photovoltaic module, and the second boost circuit 220 connects the secondary winding of the transformer T1, the controller U1, and the first boost circuit 210, and is grounded through a ground resistor R1.

The controller U1 outputs PWM signals to the switch units in the first and second boost circuits 210 and 220 from the corresponding ports according to the type of the photovoltaic module, and controls the corresponding switch units to operate for ac processing. The controller U1 may output PWM signals with the same pulse frequency to the corresponding switch units, where the pulse frequency of the PWM signals is 2 times of the ac frequency.

In one embodiment, the first boost circuit 210 includes a switch unit IGBT, a switch unit IGBT2, a switch unit IGBT5, and a switch unit IGBT5, a control terminal of the switch unit IGBT1, a control terminal of the switch unit IGBT2, a control terminal of the switch unit IGBT5, and a control terminal of the switch unit IGBT6 are all connected to the controller U1, an input terminal of the switch unit IGBT1 is connected to an input terminal of the switch unit IGBT5, an output terminal of the switch unit IGBT1 is connected to an output terminal of the switch unit IGBT2, and an input terminal of the switch unit IGBT2 is connected to a first terminal of the secondary winding of the transformer T1; the input end of the switch unit IGBT5 is connected with the negative pole PV of the photovoltaic module, the output end of the switch unit IGBT5 is connected with the output end of the switch unit IGBT6, and the input end of the switch unit IGBT6 is connected with the second end of the secondary winding of the transformer T1.

Correspondingly, the second lifting circuit 220 comprises a switch unit IGBT3, a switch unit IGBT4, a switch unit IGBT7 and a switch unit IGBT8, a control end of the switch unit IGBT3, a control end of the switch unit IGBT4, a control end of the switch unit IGBT7 and a control end of the switch unit IGBT8 are all connected with the controller U1, an input end of the switch unit IGBT3 is connected with a first end of a secondary winding of the transformer T1, an output end of the switch unit IGBT3 is connected with an output end of the switch unit IGBT4, an input end of the switch unit IGBT4 is connected with a first end of a ground resistor R1, and a second end of the ground resistor R1 is grounded; the input end of the switch unit IGBT7 is connected with the second end of the secondary winding of the transformer T1, the output end of the switch unit IGBT7 is connected with the output end of the switch unit IGBT8, and the input end of the switch unit IGBT8 is connected with the first end of the grounding resistor R1; wherein each switching unit freewheels through a freewheeling diode when turned off.

Specifically, each switch unit may employ an IGBT (Insulated Gate Bipolar Transistor) switch tube. The transformer T1 is connected to the gates of the switching unit IGBT, the switching unit IGBT2, the switching unit IGBT3, the switching unit IGBT4, the switching unit IGBT5, the switching unit IGBT6, the switching unit IGBT7, and the switching unit IGBT8 through the port PWM1, the port PWM2, the port PWM3, the port PWM4, the port PWM5, the port PWM6, the port PWM7, and the port PWM8, respectively, with the emitter of each switching unit serving as an output terminal and the collector serving as an input terminal.

When the photovoltaic module needing voltage boosting is a P-type photovoltaic module, the negative bus of the photovoltaic module is required to boost positive voltage to the ground, so that the PID effect of the photovoltaic module is repaired, at the moment, the voltage boosting circuit 200 is required to output direct-current positive voltage, the ports PWM1, PWM3, PWM5 and PWM7 of the controller U1 always output low level, so that the switch units IGBT1, IGBT3, IGBT5 and IGBT7 are always kept in an off state, current flows through a freewheeling diode of an IGBT switching tube, and the output voltage is controlled to be positive voltage. The controller U1 controls the on/off of the corresponding IGBT switch tube by controlling the duty ratio of PWM signals sent by the ports PWM2, PWM4, PWM6 and PWM8, so that the controllable lifting voltage is realized. The working principle of the rectifier is the combination of single-phase full-bridge rectification and uncontrolled rectification, the switching units IGBT1, IGBT3, IGBT5 and IGBT7 are in a diode state and can be regarded as uncontrolled rectification, the output voltage is controlled to be positive voltage, and the switching units IGBT2, IGBT4, IGBT6 and IGBT8 can be regarded as a single-phase full-bridge rectification circuit and are used for controlling the amplitude of the output voltage. The switching units IGBT1, IGBT3, IGBT5 and IGBT7 are always in a diode freewheeling state and are used for controlling the current flow direction and are only conducted when the current is positive, therefore, the switching units PWM2, PWM4, PWM6 and PWM8 can share the same pulse, the PWM algorithm is simplified, the switching frequency of the shared PWM pulse is 2 times of the alternating current frequency, and at the moment, the controller U1 controls the duty ratio of the ports PWM2, PWM4, PWM6 and PWM8 and can control the raised direct current voltage.

When the photovoltaic module is an N-type module, the negative voltage of the negative bus of the photovoltaic module needs to be raised to the ground to repair the PID effect of the photovoltaic module, at this time, the voltage raising circuit 200 needs to output the negative voltage, the working principle is the same as that of the positive voltage raising, at this time, the ports PWM2, PWM4, PWM6 and PWM8 of the controller U1 always send out low levels, so that the switching units IGBT2, IGBT4, IGBT6 and IGBT8 are continuously maintained in an off state, current continues to flow through a freewheeling diode of an IGBT switching tube, and the output voltage is the negative voltage. The controller U1 controls the on/off of the corresponding IGBT switch tube and the raised direct-current voltage by controlling the duty ratio of PWM sent by the ports PWM1, PWM3, PWM5 and PWM 7. By controlling each path of PWM signal, the adjustable bipolar voltage of the voltage lifting circuit 200 is realized, and the voltage lifting circuit can be generally used for PID effect repair of P-type and N-type photovoltaic modules.

In one embodiment, with continued reference to fig. 5, the voltage boost circuit 200 further includes a voltage sensor V1, a capacitor C1, and a control switch K1, wherein the voltage sensor V1 and the capacitor C1 are connected in parallel and then have one end connected to the first boost circuit 210 and the other end connected to the second boost circuit 220; the secondary winding of the transformer T1 is connected to the first boost circuit 210 and the second boost circuit 220 through a control switch K1.

Specifically, one end of the voltage sensor V1 and the capacitor C1 is connected to the input end of the switching unit IGBT5 in the first boost circuit 210, and the other end of the voltage sensor V1 and the capacitor C1 is connected to the input end of the switching unit IGBT8 in the second boost circuit 220. The voltage sensor V1 is also connected to the controller U1 and uploads a sensor sampling signal to the controller U1. The first end of the secondary winding of the transformer T1 is connected to the input terminal of the switching unit IGBT2 and the input terminal of the switching unit IGBT3 through the control switch K1, and the control terminal of the control switch K1 is connected to the controller U1. The capacitor C1 is used for filtering the voltage outputted from the voltage boost circuit 200.

The voltage sensor V1 for sampling voltage is added on the output side of the voltage boost circuit 200, the output voltage is sampled, the obtained sampled voltage is fed back to the controller U1, when the voltage boost circuit 200 starts to operate, the controller U1 continuously samples the boosted voltage, when the boosted voltage is detected to be 0, the voltage boost circuit 200 is indicated to be short-circuited, at the moment, the controller U1 enables the control switch K1 to be turned off, the voltage boost circuit 200 stops operating, and the voltage boost circuit 200 is protected. When the reverse of the boost voltage is detected, the controller U1 adjusts the output PWM signal so that the boost voltage is adjusted to the correct voltage.

Referring to fig. 6, a waveform a is one of the PWM waves emitted by the controller U1, a waveform B is a sine wave of the output side of the transformer T1, a waveform C is an ac input current when the voltage boost circuit 200 outputs no load, and a waveform D is a voltage waveform output by the voltage boost circuit 200. The basic operation principle of the voltage boost circuit 200 is single-phase full-bridge rectification, and a controller U1 is added to control whether the output voltage is positive or negative.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.