CN114094934A

CN114094934A - Photovoltaic module turn-off module and turn-off method

Info

Publication number: CN114094934A
Application number: CN202010859981.0A
Authority: CN
Inventors: 张永
Original assignee: FONRICH NEW ENERGY TECHNOLOGY Ltd SHANGHAI
Current assignee: FONRICH NEW ENERGY TECHNOLOGY Ltd SHANGHAI
Priority date: 2020-08-24
Filing date: 2020-08-24
Publication date: 2022-02-25
Anticipated expiration: 2040-08-24
Also published as: CN114094934B

Abstract

The invention relates to a photovoltaic module turn-off module and a turn-off method. The turn-off module for supporting the rapid turn-off of the photovoltaic module comprises a change-over switch which is equipped for the photovoltaic module and is used for controlling whether the photovoltaic module is turned off or not. The controller is used for controlling the on or off of the switch. And a communication unit for loading the signal generated by the communication unit onto a cable in which the multi-stage photovoltaic modules are connected in series and extracting the returned signal from the cable. The controller operates the communication unit to continuously send signals onto the cable and the controller also continuously monitors signals returned from the cable by the communication unit. The controller also monitors the attenuation degree of the returned signal, and if the attenuation degree reaches a preset attenuation value, the change-over switch is switched off to switch off the photovoltaic assembly.

Description

Photovoltaic module turn-off module and turn-off method

Technical Field

The invention mainly relates to the technical field of photovoltaic power generation, in particular to a photovoltaic module turn-off module and a turn-off method applied to the aspect of a rapid turn-off function of a photovoltaic module.

Background

The photovoltaic module is used as an important core component of a photovoltaic power generation system, the excellent performance of the photovoltaic module directly influences the overall effect of the power generation system, but in practice, the photovoltaic module is subjected to more restriction factors, and the characteristic difference of each battery module can cause the loss of the connection combination efficiency. The photovoltaic module array is generally in series-parallel connection, and if one of the battery modules is subjected to power reduction caused by shadow or dust, or shading or aging, all the battery modules connected in series in the link may be affected by the reduction of the current intensity. In order to guarantee the safety and reliability of the operation of the photovoltaic array, it is important to fully exert the maximum power generation efficiency of each photovoltaic cell module and guarantee that the photovoltaic cell module is in a normal working state.

Photovoltaic power generation systems considered to be in the high voltage field need to meet electrical safety regulations. In recent years, in countries such as the united states and europe, mandatory requirements are gradually added to relevant electrical specifications for safety. Corresponding laws and regulations are respectively set for governments or related organizations of various countries. Based on electrical mandatory regulations, the american fire protection association modifies national electrical regulations, specifying among residential photovoltaic power generation systems: when an emergency occurs, the voltage of a direct current terminal cannot exceed eighty volts to the maximum extent after an alternating current grid-connected end of the photovoltaic power generation system is required to be disconnected. Italian safety regulations caution: firefighters are absolutely not allowed to perform a fire extinguishing operation with a building charged with voltage. Germany also has first implemented fire safety standards and also stipulates in plain text: an additional direct current cut-off device needs to be added between an inverter and a component in the photovoltaic power generation system. The power electronic technology of the photovoltaic module level is a main mode for realizing module level shutdown, and application products comprise a micro inverter, a power optimizer and an intelligent control shutdown device. The use of the micro inverter can fundamentally eliminate direct current high voltage existing in a photovoltaic system, and the photovoltaic module power optimizer and the intelligent control shutoff device have a module level shutoff function. The photovoltaic system provided with the power optimizer or the intelligent control breaker under emergency can timely cut off the connection between each module, eliminate the direct current high voltage existing in the array and realize the rapid turn-off of the module level.

Taking the american safety code NEC2017 as an example, a photovoltaic power generation system is required to have a rapid turn-off function, and the voltage between conductors inside a photovoltaic array and between the conductors and the ground must not exceed about eighty volts at the maximum after turn-off. The photovoltaic power station should actively take the following measures in the face of safety regulations: in order to achieve rapid shutdown, a shutdown module for shutdown must be installed at the output of the photovoltaic module, a command transmission device is installed on a battery string or a dc bus that supplies dc power, and the command transmission device needs to be manually controlled. For example, in case of fire, it is necessary to actively and rapidly turn off the photovoltaic module to cut off the dc power, and the command transmitting device is used to instruct the turn-off module to turn off. The countermeasure of shutting down the photovoltaic module can prevent further deterioration of negative events such as fire and the like, and improve reliability and safety.

In many national regions, the rapid switching off of the photovoltaic facilities at the module level has been regarded as a mandatory requirement, and as a china with extremely wide photovoltaic distribution, the standards are not established in the field, and the safety standards fall behind the product manufacturing and market promotion. At present, only the local standard of the entrance of the public security fire-fighting headquarters in Anhui province and province puts forward the standardized requirements. Although the community standards are introduced in Zhejiang and Jiaxing, etc., no mandatory requirement is imposed on the rapid turn-off of the components, and only concepts such as proper provision are provided. The rapid shutdown of the component level is urgently needed to be deeply researched and applied in case of fire of a photovoltaic power station for a plurality of rooftop users at home and abroad. Potential safety risks are more likely to be exposed when photovoltaic is pervaded as a daily rooftop installation. On one hand, the requirements on design specification, construction and acceptance are provided from the aspect of safety consciousness to ensure that property and personal safety are guaranteed, on the other hand, the industry is actively promoted to establish a more popular mandatory safety standard as soon as possible, and a photovoltaic module turn-off module suitable for a quick turn-off function is developed.

Disclosure of Invention

In an alternative example, the present application discloses a shutdown module for rapid shutdown of a photovoltaic module, comprising:

the change-over switch is equipped for the photovoltaic module and is used for controlling whether the photovoltaic module is switched off or not;

the controller controls the on or off of the selector switch;

the communication unit is used for loading the signals generated by the communication unit onto a cable which is connected with the multi-stage photovoltaic modules in series and extracting the returned signals from the cable;

the controller operates the communication unit to continuously send signals onto the cable;

the controller continuously monitors signals returned from the cable through the communication unit;

the controller also monitors the attenuation degree of the returned signal, and if the attenuation degree reaches a preset attenuation value:

the diverter switch is opened to turn off the photovoltaic module.

In the above shutdown module, the signal is one of a power line carrier signal, a periodic signal, and a non-periodic signal.

The shutdown module described above, wherein:

the multistage photovoltaic modules are connected in series, and each stage of photovoltaic module is provided with a turn-off module;

the shutdown module of any one stage of photovoltaic assembly determines whether the photovoltaic assembly is shut down or not by monitoring a signal generated by the shutdown module and returned by the shutdown module.

The shutdown module described above, wherein:

the shutdown module of any one stage of photovoltaic assembly determines whether any one stage of photovoltaic assembly is shut down or not by monitoring signals which are generated by and returned from the shutdown modules of other photovoltaic assemblies.

The shutdown module described above, wherein: the attenuation degree of the signal reaches a preset attenuation value, including the condition of attenuation to zero point decibel, namely the condition that the controller does not receive the returned signal.

The shutdown module described above, wherein: and an attenuator is arranged on the cable, and the attenuator is used for adjusting the attenuation degree of the signal so as to enable the attenuation degree of the returned signal to reach a preset attenuation value.

The shutdown module described above, wherein: and a main control switch is arranged on the cable, and the propagation path of the signal is directly disconnected in a mode of disconnecting the main control switch, so that the controller cannot receive the returned signal.

The shutdown module described above, wherein: the signal is disturbed by actively injecting additional noise pulses on the cable so that the returned signal is attenuated to a predetermined attenuation value.

The shutdown module described above, wherein: absorbing a portion of the signal on the cable with a coupling device to attenuate the signal such that the returned signal is attenuated to a predetermined attenuation value.

The shutdown module described above, wherein:

the cable is provided with an inductance element, a capacitance element and a relay, the capacitance element is connected with the relay in series and then connected with the inductance element in parallel, and the attenuation degree of the returned signal reaches a preset attenuation value in a mode of disconnecting the relay.

The shutdown module described above, wherein: the mode of re-enabling the shut-down photovoltaic module is:

and sending another set of signals carrying the starting instruction to the turn-off module, receiving the starting instruction by the controller through a matched communication unit, and turning on the change-over switch by the controller in response to the starting instruction to enable the photovoltaic module to be restored to the on state.

The shutdown module described above, wherein: the output voltages of the multi-stage photovoltaic modules are superposed and then are supplied to an inverter;

forming a loop between the series-connected multi-stage photovoltaic modules and the inverter;

and the signal sent by the shutdown module of each stage of photovoltaic assembly is transmitted to the inverter and then returned to the multi-stage photovoltaic assemblies along a loop.

In an alternative example, the present application discloses a method of shutting down a photovoltaic module, comprising:

the output end of the photovoltaic module is provided with a change-over switch for controlling the turn-off state of the photovoltaic module;

controlling the on or off of the selector switch by using a controller, wherein the controller is provided with a communication unit;

operating, by the controller, the communication unit to continuously send signals onto cables that serially connect the multiple photovoltaic modules;

continuously monitoring, by the controller, a signal returned from the cable via the communication unit;

judging whether the attenuation degree of the returned signal reaches a preset attenuation value or not by the controller;

and if so, disconnecting the change-over switch to turn off the photovoltaic module.

The method described above, wherein: the output voltages of the multi-stage photovoltaic modules are superposed and then are supplied to an inverter;

The method described above, wherein: a turn-off control module with a main control switch connected to the cable is arranged in the loop;

and directly disconnecting the propagation path of the signal in a manner of disconnecting the main control switch, so that the controller cannot receive the returned signal.

The method described above, wherein: a turn-off control module is arranged in the loop, and the mode of turning off the photovoltaic module at the turn-off control module is as follows: additional noise pulses are actively injected into the cable to interfere with the signal or a coupling device is used on the cable to absorb a portion of the signal to attenuate the signal to a predetermined attenuation level.

The method described above, wherein: a turn-off control module with an attenuator connected to the cable is arranged in the loop;

and adjusting the attenuation degree of the signal by an attenuator to enable the attenuation degree of the returned signal to reach a preset attenuation value.

The method described above, wherein: the multistage photovoltaic modules are connected in series, and each stage of photovoltaic module is provided with a turn-off module;

the method comprises the following steps of setting a plurality of photovoltaic modules to be connected in series, and providing the output voltages of the photovoltaic modules to an inverter after the output voltages are mutually superposed;

a loop is formed between the multi-stage photovoltaic module and the inverter;

configuring a turn-off module at the output end of each stage of photovoltaic module;

the shutdown module of each level of photovoltaic module configuration includes:

a change-over switch for controlling whether each stage of photovoltaic module is switched off or not;

a controller for controlling the on/off of the switch, the controller being provided with a communication unit;

the controller operates the communication unit to continuously send signals to cables which are connected with the multi-stage photovoltaic modules in series;

the turn-off method comprises the following steps:

and judging whether the attenuation degree of the returned signal reaches a preset attenuation value or not by the controller in the turn-off module of each stage of photovoltaic assembly, and if so, turning off the change-over switch to turn off the photovoltaic assembly.

The method described above, wherein:

the shutdown module of any one-level photovoltaic module determines whether the any one-level photovoltaic module is shut down or not by monitoring a signal which is generated by the shutdown module and returned by a loop; or

The shutdown module of any one-stage photovoltaic assembly determines whether any one-stage photovoltaic assembly is shut down or not by monitoring signals which are generated by the shutdown modules of other photovoltaic assemblies and returned through the loop.

The method described above, wherein:

a turn-off control module with a main control switch connected to the cable is arranged in the loop;

The method described above, wherein:

a turn-off control module is arranged in the loop, and the mode of turning off the photovoltaic module at the turn-off control module is as follows:

the method comprises the steps of actively injecting extra noise pulses generated by a noise source into a cable to disturb the signal, or absorbing a part of the signal from the cable by using a coupling device to weaken the signal, or adjusting the impedance in a loop to ensure that the returned signal is attenuated to a preset attenuation value.

a voltage converter provided to the photovoltaic module for performing voltage conversion on an initial voltage output from the photovoltaic module and also providing an output voltage;

a controller for operating the voltage converter to perform voltage conversion;

a communication unit for loading the signal generated by the communication unit onto a cable in which a plurality of voltage converters are connected in series and extracting a returned signal from the cable;

the controller adjusts the output voltage of the voltage converter down.

The shutdown module described above, wherein:

the voltage converters corresponding to the multi-level photovoltaic module are connected in series, the output voltages of the voltage converters are superposed and then supplied to an inverter, and a loop is formed between the voltage converters and the inverter;

the signal sent by the shutdown module of each stage of photovoltaic assembly is transmitted to the inverter and then returned to the plurality of voltage converters along a loop.

The shutdown module described above, wherein:

the cable is provided with a turn-off control module which is provided with a main control switch connected with the cable;

The shutdown module described above, wherein:

the cable is provided with a turn-off control module, and the mode of turning off the photovoltaic module at the turn-off control module is as follows:

Drawings

To make the above objects, features and advantages more comprehensible, embodiments accompanied with figures are described in detail below, and features and advantages of the present invention will become apparent upon reading the following detailed description and upon reference to the following figures.

Fig. 1 is a schematic diagram of photovoltaic modules connected in series to form a battery string and then connected in parallel by the battery string to power an inverter.

Fig. 2 is a topological schematic diagram of a photovoltaic module configured with a shutdown module and a shutdown control module.

Fig. 3 is a schematic of the topology of the shutdown module with the controller and the communication unit and the diverter switch.

Fig. 4 is a power line carrier signal generated and returned by the shutdown module itself for each photovoltaic module stage.

Fig. 5 is an embodiment in which the shutdown module of each photovoltaic module stage cannot receive a returned power line carrier signal.

Fig. 6 is a diagram of each photovoltaic module shutdown module monitoring power line carrier signals generated by other shutdown modules.

Fig. 7 shows that the shutdown module of each photovoltaic module stage cannot receive the power line carrier signals of other shutdown modules.

Fig. 8 is a schematic diagram of interference of a power line carrier signal on a cable by actively injecting additional noise pulses.

Fig. 9 illustrates the attenuation of a power line carrier signal by absorbing a portion of the power line carrier signal with a coupling device.

Fig. 10 is a diagram of opening a relay at a shutdown control module with a relay to attenuate a power line carrier signal.

Fig. 11 is a diagram of adjusting an attenuator at a shutdown control module with the attenuator such that a power line carrier signal is attenuated.

FIG. 12 is a signal applied to a cable having a plurality of voltage converters connected in series and a return signal extracted from the cable.

Detailed Description

The invention will now be described more fully hereinafter with reference to the accompanying examples, in which the invention is shown by way of illustration only, and not in all embodiments. Based on the embodiments, the technical personnel in the field can obtain the proposal without creative labor and belong to the protection scope of the invention.

Referring to fig. 1, as environmental and conventional energy problems become more severe, the photovoltaic power generation technology has been emphasized by more and more countries and regions and is regarded as a priority development object, and the photovoltaic power generation is one of the most mature and most developed scale power generation modes in the new energy power generation technology. Solar photovoltaic modules are divided into monocrystalline silicon solar cells, polycrystalline silicon solar cells, amorphous silicon solar cells and the like in the current mainstream technology direction, and the service life required by the silicon cells is generally as long as more than twenty years, so that the solar photovoltaic modules are essential for long-term and durable control of the solar photovoltaic modules. It is a well-known problem that many factors cause a reduction in the power generation efficiency of the photovoltaic module, for example, manufacturing differences, installation differences or shading or maximum power tracking adaptation among the photovoltaic modules themselves cause inefficiency. Taking shadow blocking as an example, if some photovoltaic modules are blocked by clouds, buildings, tree shadows, dirt, and the like, some photovoltaic modules become loads from the power supply and no longer generate electric energy and consume the output power of other photovoltaic modules. For example, when the same string of battery plates cannot normally generate electricity due to poor product consistency or shading, the efficiency loss of the whole string of battery packs is serious and the number of battery plate arrays accessed by inverters, especially centralized inverters, is large, the battery plates of each string of battery packs cannot operate at the maximum power point of the battery plates, which are the inducement of the loss of electric energy and generated energy. Because the local temperature of the photovoltaic module at a place with a serious hot spot effect may be higher, some of the photovoltaic modules even exceed 150 ℃, the photovoltaic module is burnt or forms dark spots, welding spots are melted, packaging materials are aged, glass is burst, welding strips are corroded and other permanent damages are caused, and the potential hazards to the safety and the reliability of the photovoltaic module are caused. The photovoltaic system has to solve the problems of real-time management and control of photovoltaic modules and management of the photovoltaic modules, and the specific requirements are that the working state and working parameters of each mounted photovoltaic cell panel can be managed and controlled in real time, the voltage abnormity, current abnormity, temperature abnormity and other abnormal conditions of the photovoltaic modules can be reliably pre-warned, and some countermeasures are taken, so that the adoption of module-level active safety shutdown or other emergency power-off measures for the abnormal battery modules is very significant and necessary.

Referring to fig. 1, a photovoltaic module array is the basis for the conversion of light energy to electrical energy in a photovoltaic power generation system. The photovoltaic module array is provided with a battery string which is formed by serially connecting photovoltaic modules PV 1-PVN. The total electrical energy provided by the array of photovoltaic modules is delivered by a dc bus to an energy harvesting device or to an energy harvesting device, which may include an inverter INVT as shown to invert dc power to ac power or a charger to charge a battery. Usually, a bypass diode connected in parallel with the photovoltaic module is connected between the positive electrode and the negative electrode of each photovoltaic module, so that when the output power of the photovoltaic module is reduced, the photovoltaic module can be bypassed by the bypass diode matched with the photovoltaic module, rather than the photovoltaic module with reduced output power entering a negative pressure region, which would otherwise cause extremely high power dissipation at the two ends of the photovoltaic module, and even cause combustion.

Referring to fig. 2, the associated off state in the string of batteries, such as the first stage photovoltaic module PV1, is managed by its companion module off module RSD1 to perform the off function. The off state of the second stage photovoltaic module PV2 is managed by a self-contained module off module RSD2 to perform the off function. And in analogy, the shutdown state of the photovoltaic module PVN of the Nth level is managed by a shutdown module RSDN matched with the photovoltaic module PVN, and N is a positive integer not lower than 1.

Referring to fig. 2, the output voltage of the first stage photovoltaic module PV1 is V_O1. The output voltage of the second stage photovoltaic module PV2 is noted as V_O2. And so on, the output voltage of the Nth-stage photovoltaic module PVN is V_ON. So that the total bus voltage on any string of photovoltaic cells is calculated to be about V_O1+V_O2+…V_ON=V_BUS. Different groups of battery packs are connected between the buses in series and parallel. The multi-stage photovoltaic modules PV1 to PVN are connected in series, the output voltages of the multi-stage photovoltaic modules are mutually superposed on a bus, and the bus voltage V_BUSIs much higher than that of a single photovoltaic module, and the inverter is shown as a bus voltage V for direct current from the bus_BUSAnd inverting and converting the alternating current into alternating current.

Referring to fig. 3, the shutdown module RSDN includes a controller IC. The controller IC may perform one-way or two-way communication with the outside by controlling the communication unit MODU equipped therewith in terms of communication. The communication mechanism of the communication unit MODU includes two types of wired communication and wireless communication: for example, all existing wireless communication schemes such as WIFI, ZIGBEE, 433MHZ communication, infrared or bluetooth, etc. may be adopted, and for example, a scheme of power line carrier communication may also be adopted. In an alternative example of the present application, the communication unit MODU includes a power line carrier modem, and the power line carrier modem is used for implementing unidirectional or bidirectional communication in a power line carrier manner. The coupling element COP shown couples a power line carrier signal from a power line carrier modem to a cable, typically a transformer with a primary and secondary winding or a signal coupler with a coupling coil, for example. The coupling transformer can be used, for example, to transmit a power line carrier to the primary winding and the secondary winding to the power cable as part of the cable, the power line carrier being transmitted to the cable by the coupling of the primary and secondary windings. A typical method of using a signal coupler with a magnetic loop and a coupling coil is to pass a bus cable directly through the magnetic loop of the signal coupler around which the coupling coil is wound, and to feed a power line carrier to the coupling coil, where it is sensed from the bus cable, so that a contactless signal transfer can be performed. In summary, all signal coupling schemes disclosed in the prior art can be adopted for the coupling element, and injection type inductive coupler technology, cable clamping type inductive coupler technology and switchable full impedance matching cable clamping type inductive coupler are all alternatives of the application. In addition to the power line carrier signal propagating along the cable in a desired direction away from the photovoltaic module, such as toward the inverter, the power line carrier signal synchronization also propagates directly in reverse direction to the positive and negative electrodes of the photovoltaic module, after all, the communication unit is closer to the photovoltaic module.

With reference to fig. 3, the communication unit MODU allows, in addition to the coupling element COP, the implementation of a carrier signal coupling circuit SENS for sensing power line carrier signals from the cable, note that the former is the transmission and loading of power line carrier signals onto the cable at the shutdown module of the photovoltaic module, while the latter is the sensing and capturing of power line carrier signals returned from the cable to the shutdown module of the photovoltaic module. The coupling circuit SENS is, for example, a transformer with a primary side secondary winding or a signal coupler with a coupling coil, and is, for example, any one of a rogowski air coil sensor or a high-frequency sensor, a codec, a shunt, and the like, and is used for detecting and monitoring a power line carrier signal on a transmission cable returned to a shutdown module of the photovoltaic module. Spread spectrum communication is spread spectrum communication technology, and the basic technical characteristic is that the signal bandwidth occupied by the transmitted information is far larger than the bandwidth of the information. Spread spectrum communication has the following meaning, and spread spectrum communication also has the following features: the method is a digital transmission mode, the spreading of the signal bandwidth at the transmitting end is realized by modulating transmission information through pseudo-random coding with high code rate, and the transmitted information is restored by performing related demodulation on a spread spectrum signal by using the same pseudo-random coding at the receiving end. The theoretical basis of spread spectrum communication is the well-known theorem in information theory on channel capacity, namely the shannon formula: when the transmission rate of the signal is equal to the signal bandwidth, the signal-to-noise ratio can be interchanged, i.e. the signal bandwidth is increased to reduce the requirement on the signal-to-noise ratio. The signal power can approach the noise power when the bandwidth is increased to a certain extent, and communication can be maintained even in the case where the signal is drowned out by noise. Spread spectrum communication is a benefit of broadband transmission technology in exchange for signal-to-noise ratio, which is the basic idea and theoretical basis of spread spectrum communication. The spread spectrum communication technology, the amplitude modulation technology, the frequency shift keying, the orthogonal frequency division and other adjusting modes are suitable for power line carrier communication. Although amplitude modulation is difficult to ensure reliable communication, the noise pulse additionally added to the cable can easily interfere with the power line carrier signal under amplitude modulation and make the specified parameter unable to meet the preset characteristic, so that amplitude modulation is a better choice when the power line carrier signal is interfered by actively injecting the additional noise pulse into the cable. Frequency shift keying is applied to power line narrowband communication and orthogonal frequency division is applied to power line broadband communication, and spread spectrum communication is applied to both power line narrowband communication and power line broadband communication. The modulation and demodulation of the power line carrier communication can adopt the prior art.

Referring to fig. 3, in the shutdown module supporting the rapid shutdown management of the photovoltaic module, a component shutdown module RSDN which can control whether the photovoltaic module is shutdown is taken as an example as shown in the figure. The intelligent management objective that the circuit adopting the turn-off module RSDN is expected to achieve is to judge whether the photovoltaic module is necessary to be turned off in time, meeting NEC690.12 clauses: photovoltaic systems installed or built into buildings must include a quick shut-off function, reducing the risk of electrical shock to emergency personnel. Although the component management module is described by taking the component shutdown module implementing the shutdown function as an example, the component shutdown module is in fact far from being limited in function to the data monitoring function or the component shutdown function. For example, each of the multilevel PV modules PV1-PVN is configured with a voltage converter, and the output voltages of the voltage converters corresponding to the multilevel PV modules PV1-PVN are required to be superimposed on the dc bus and thereby be used as the bus voltage, when the voltage converters are connected in series. Each voltage converter converts the electric energy extracted from the corresponding photovoltaic module into the output power of the voltage converter. Each voltage converter also performs processing such as voltage boosting or voltage reduction or voltage boosting and voltage reduction on the output voltage of the corresponding photovoltaic module and then outputs the output voltage. Even in an alternative example, each voltage converter is further configured to set the output current and the output voltage of a corresponding one of the photovoltaic modules at the maximum power point, so as to achieve a power optimization effect on the photovoltaic modules. The controller IC of the device management apparatus can be used to operate the voltage converter to perform voltage conversion such as step-up, step-down, step-up, or step-down, so that the shutdown module can also have a voltage regulation function and a power management function.

Referring to fig. 3, the turn-off module RSD1 supporting fast turn-off of the photovoltaic module PV1 in an alternative example is used to operate the switch S2 of the photovoltaic module configuration to turn off or on, and control whether the photovoltaic module PV1 is turned off or not. In contrast, in other alternative examples, the turn-off module RSD2 supporting the rapid turn-off of the PV module PV2 is used to operate the switch S2 of the PV module configuration to turn off or on, and control whether the PV module PV2 is turned off or not. In contrast, in other alternative examples, the turn-off module RSDN supporting the rapid turn-off of the pv device PVN is used to operate the switch S2 of the pv device configuration to turn off or turn on, so as to control whether the pv device PVN is turned off or not.

Referring to fig. 3, in an alternative example, the photovoltaic module PV1 is connected to the power cable through the diverter switch S2 and the diverter switch S2 is controlled by the controller IC: if the switch S2 is turned off, the PV module PV1 is removed from the string of series-connected multilevel PV modules PV1-PVN, i.e. battery packs, and if the switch S2 is turned on, the PV module PV1 is restored to the string of PV modules PV1-PVN, i.e. battery packs. And the module PV2 is connected to the power cable by the switch S2 and the switch S2 is controlled by the controller IC: if the switch S2 is turned off, the PV module PV2 is removed from the string of series-connected multilevel PV modules PV1-PVN, i.e. battery packs, and if the switch S2 is turned on, the PV module PV2 is restored to the string of PV modules PV1-PVN, i.e. battery packs. The component PVN is connected to the power supply cable via the changeover switch S2 and the changeover switch S2 is controlled by the controller IC: if the switch S2 is turned off, the PV modules PVN are removed from the string of series-connected multi-stage PV modules PV1-PVN, i.e. battery packs, and the switch S2 is turned on, and the PV modules PVN are restored to be connected to the string of PV modules PV1-PVN, i.e. battery packs. Thus in an alternative embodiment where the module shutdown module controls whether the photovoltaic module is shutdown: each photovoltaic module is provided with a diverter switch S2, the photovoltaic modules PV1-PVN being connected in series and they being connected in series in a so-called battery string. Each of the switches S2 is used to turn off a corresponding one of the pv modules and remove it from the string of the battery pack, and each of the switches S2 is also used to restore the corresponding one of the pv modules from the off state into the string of the battery pack. The changeover switch S2 of each photovoltaic module arrangement is controlled by the controller IC of the module shutdown module of each photovoltaic module arrangement. The photovoltaic module is provided with a bypass diode BD connected in parallel with it so that when the photovoltaic module is removed from the string of battery packs, it can be bypassed by the associated bypass diode BD without the string of battery packs forming a so-called trip point at the removed photovoltaic module. The pv module PVN is bypassed by its associated bypass diode BD assuming it is removed from the string of batteries.

Referring to fig. 3, in an alternative example, if photovoltaic modules PV1-PVN are all turned off, the total bus voltage across the battery string, i.e., V_O1+V_O2+…V_ON=V_BUSCan drop rapidly from a few hundred volts to near zero. Can enable the photovoltaic systemA quick shut-off function is implemented to reduce the risk of electric shock to emergency treatment personnel. Meet NEC690.12 clauses.

Referring to fig. 3, in an alternative example, the turn-off module RSDN for fast turn-off of the pv module includes a switch S2 provided to the pv module PVN for controlling whether the pv module PVN is turned off. A controller IC that controls the on or off of the switch S2 is also included. And a communication unit MODU for loading the power line carrier signal generated by the communication unit MODU onto a cable connected in series with the multistage photovoltaic modules PV1-PVN and extracting the power line carrier signal from the cable back to the local of the shutdown module RSDN. The controller IC operates the communication unit MODU to continuously send a power line carrier signal having a predetermined characteristic to the cable, and the controller IC continuously monitors the power line carrier signal returned from the cable to the location of the shutdown module RSDN by the communication unit MODU. The coupling element COP needs to couple a power line carrier signal sent by the power line carrier modem to a cable, the controller IC can transmit data information to be sent to the communication unit MODU, and then the communication unit MODU modulates the data information and couples the modulated data information to the cable through the power line carrier signal to realize a data information sending function. And the coupling circuit SENS senses and captures a power line carrier signal returned from the cable to the switching-off module RSDN of the photovoltaic module, the sensed and extracted power line carrier signal is further transmitted to the communication unit MODU, and the communication unit MODU decodes data information from the power line carrier carrying the data information and sends the data information to the controller IC so as to realize the receiving function of the data information. The present application divides the coupling circuit SENS and the coupling element COP into two parts for convenience of explanation, essentially both of which are sometimes allowed to be directly integrated together and as a whole, and the coupling circuit SENS and the coupling element COP are collectively referred to as a signal coupler and they are key units for coupling the carrier communication unit with the power line, i.e. the cable.

Referring to fig. 3, in an alternative example, the communication unit MODU loads a signal (signal) on the cable connecting the photovoltaic modules in series and extracts a return signal from the cable, the controller IC operates the communication unit MODU to continuously send a signal to the cable, the controller IC continuously monitors the signal returned from the cable by the communication unit MODU and the controller IC also monitors the degree of attenuation of the returned signal, the triggering condition whether to turn off the photovoltaic module: if the attenuation level of the returned signal reaches a predetermined attenuation value (attenuation value), the switch S2 is opened to switch off the so-called photovoltaic module, for example, to switch off the photovoltaic module PVN. The attenuation values are typically in decibels.

Referring to fig. 4, in an alternative example, it is assumed that the shutdown module RSD2 of the PV module PV2 couples the power line carrier signal PLC sent by its communication unit to the positive bus LA, and the power line carrier signal PLC propagates along the bus, passes through the inverter INVT, and returns to the multi-stage PV modules PV1-PVN along the negative bus LB, and the physical carrier constituting the bus is actually an electrically conductive cable. The output voltages of the photovoltaic modules PV1-PVN are superposed and then are supplied to the inverter INVT, a loop is formed between the photovoltaic modules PV1-PVN and the inverter INVT which are connected in series, and a power line carrier signal sent by a shutdown module of each photovoltaic module is transmitted to the inverter INVT and then returns to the photovoltaic modules along the loop. For example, the power line carrier signal PLC sent by the shutdown module RSD2 is transmitted to the inverter and then returned to the multi-stage PV assemblies PV1-PVN along a loop, and the power line carrier signal PLC is transmitted to the inverter through the positive bus LA and then returned along the negative bus LB, and the power line carrier signal PLC is transmitted to the inverter through the negative bus LB and then returned along the positive bus LA. A returned power line carrier signal is thus defined to mean a power line carrier signal that propagates into the loop and then returns or retraces, a power line carrier signal that does not propagate into the loop but is sensed by the shutdown module cannot be referred to as a returned power line carrier signal. The power line carrier signal PLC emitted by the communication unit of the shutdown module RSD2 is not only remotely propagated in the desired direction away from the PV modules PV1-PVN, i.e. towards the inverter, but also dispersed in the opposite direction to the positive and negative poles of the PV module because, after all, the communication unit of the shutdown module RSD2 is closer to the PV module. The power line carrier signal PLC which is remotely propagated towards the inverter and then folded back is the returned power line carrier signal, and the power line carrier signal PLC which is dispersed locally in the photovoltaic module but does not enter the loop is not the returned power line carrier signal. A PLC, which only propagates locally in the module but does not enter the loop, is a disadvantage in determining whether to turn off the photovoltaic module.

Referring to fig. 4, the controller IC of the shutdown module RSD2 extracts the returned PLC from the cable through its communication unit MODU, and the controller IC monitors whether the designated parameter of the returned PLC satisfies the preset characteristic, and if the designated parameter does not satisfy the preset characteristic or the controller IC does not receive the PLC within a set time period, the controller IC turns off the switch S2 to shut down the PV module PV 2.

Referring to fig. 4, the carrier object monitored by the controller IC of the shutdown module RSD 2: the power line carrier signal PLC returned via the loop is generated by the communication unit MODU operatively associated with the controller IC of the shutdown module RSD 2. In an alternative embodiment, therefore, the controller IC of the shutdown module RSD2 operates the communication unit MODU to continuously send the PLC signal PLC with the predetermined characteristics to the cable, and the controller IC of the shutdown module RSD2 continuously monitors the PLC signal PLC returned from the cable by the communication unit MODU, the returned PLC signal PLC being generated by the shutdown module RSD2 itself.

Referring to fig. 4, in an alternative example, the specified parameter regarding the power line carrier signal PLC includes a magnitude of the amplitude of the power line carrier signal PLC, and the predetermined characteristic includes a predetermined magnitude value, and the photovoltaic module PV2 is turned off when the actual magnitude of the received returned power line carrier signal PLC is lower than the predetermined magnitude value.

Referring to fig. 4, in an alternative example, the aforementioned specified parameters regarding the power line carrier signal PLC include a spectral distribution of the power line carrier signal PLC in a frequency domain, the preset characteristic includes a preset spectral distribution point, and the photovoltaic module PV2 is turned off when the actual spectral distribution of the returned power line carrier signal PLC does not coincide with the preset spectral distribution point and there is a spectral distribution point missing. It follows that the parameter classes of the preset features are not unique.

Referring to fig. 4, in an alternative example, the communication unit MODU of the shutdown module RSD2 loads a signal onto the cable in series with the photovoltaic module and extracts a return signal from the cable, the controller IC operates the communication unit MODU to continuously send a signal onto the cable, the controller IC continuously monitors the signal returned from the cable by the communication unit MODU and the controller IC also monitors the degree of attenuation of the returned signal, the triggering condition whether the photovoltaic module is shut down: if the attenuation of the returned signal reaches a predetermined attenuation value, the turn-off module RSD2 turns off the switch S2 to turn off the so-called photovoltaic module, for example, the photovoltaic module PV 2. The present embodiment is an example of the shutdown module receiving and sending automatically.

Referring to fig. 5, in an alternative example, a shutdown control module CTL is provided in the loop and has a master switch S1 connected to the cable, which may be provided on the positive or negative bus. The optimal location of the shutdown control module CTL is preferably on the cable between the photovoltaic module PV1-PVN and the inverter INVT, the location of the shutdown control module CTL should also be far from the photovoltaic module PV1-PVN to ensure safety. Under emergency, the photovoltaic system provided with the voltage converter or the intelligent control turn-off module can cut off the connection between each block of components, eliminate the direct current high voltage existing in the array and realize the rapid turn-off of the component level so as to meet the guarantee in the aspects of property and personal safety. The emergency personnel switching off the master switch in the shutdown control module CTL or quickly toggling the master switch S1 to perform a toggling operation such as switching off and on and then off may cause the returned specified parameters of the power line carrier signal PLC to fail to meet the preset characteristics. For example, the actual amplitude of the returned power line carrier signal may be lower than a preset amplitude value, and for example, the actual spectral distribution of the returned power line carrier signal may not coincide with a preset spectral distribution point. If the emergency personnel cuts off the main control switch in the shutdown control module CTL to directly disconnect the propagation path of the power line carrier signal PLC on the cable, the controller IC cannot receive the returned power line carrier signal PLC because the propagation path of the carrier in the loop is directly cut off. The controller IC does not receive the power line carrier signal PLC within a set time period, which is likely to be a time period when the emergency personnel turns off the main control switch so as to determine that the switch S1 needs to be opened to turn off the photovoltaic module PV 2. The dotted line represents that the specified parameter of the returned power line carrier signal is changed after human intervention.

Referring to fig. 6, the controller IC of the shutdown module RSD2 extracts the returned PLC from the cable through its communication unit MODU, and the controller IC monitors whether the designated parameter of the returned PLC satisfies the preset characteristic, and if the designated parameter does not satisfy the preset characteristic, or if the controller IC does not receive the PLC within a set time period, the controller IC turns off the switch S2 to shut down the PV module PV 2.

Referring to fig. 6, the carrier object monitored by the controller IC of the shutdown module RSD 2: the power line carrier signal PLC returned via the loop is generated by the communication unit MODU operatively associated with the controller IC of the shutdown module RSD 1. In an alternative embodiment, therefore, the controller IC of the shutdown module RSD1 operates the communication unit MODU to continuously send the PLC signal PLC with the predetermined characteristics to the cable, and the controller IC of the shutdown module RSD2 continuously monitors the PLC signal PLC returned from the cable by the associated communication unit MODU, the returned PLC signal PLC being generated by the other shutdown module RSD 1.

Referring to fig. 5, each shutdown module has address number information burned in advance: the address number information of the turn-off module RSD1 matched with the photovoltaic component PV1 burnt in the controller IC is ADS1, the address number information of the turn-off module RSD2 matched with the photovoltaic component PV2 burnt in the controller IC is ADS2, and the address number information of the turn-off module RSD3 matched with the photovoltaic component PV3 burnt in the controller IC is ADS 3. And the address number information of the turn-off module RSDN matched with the PVN and burned in the controller IC is ADSN.

Referring to fig. 5, the shutdown module of any one stage of photovoltaic module determines whether the photovoltaic module is shutdown by monitoring the power line carrier signal generated by the shutdown module and returned by the shutdown module. The shutdown module RSD2 of the photovoltaic module RSD2 determines whether the corresponding photovoltaic module PV2 needs to be shut down, for example by monitoring the power line carrier signal PLC generated by the shutdown module RSD2 itself and returned through the loop. In an optional but not necessary example, the power line carrier signal sent by the shutdown module RSD2 carries address number information such as ADS2, allowing the shutdown module RSD2 to extract and monitor only the power line carrier signal corresponding to its own address number ADS 2. The present scheme belongs to optional but not essential items.

Referring to fig. 6, the shutdown module of any one photovoltaic module determines whether any one photovoltaic module is shutdown by monitoring the power line carrier signals generated and returned by the shutdown modules of other photovoltaic modules. The shutdown module RSD2 determines whether the corresponding PV module PV2 needs to be shut down, e.g., by monitoring the power line carrier signal PLC generated by the other shutdown modules RSD1 and returned through the loop. In an optional but not necessary example, the power line carrier signal sent by the shutdown module RSD1 carries address number information such as ADS1, allowing the shutdown module RSD2 to extract and monitor only the power line carrier signal corresponding to the address number ADS1 of the other shutdown modules RSD 1. This embodiment is also an optional but not essential item, note that setting the address number is not essential. Any shutdown module can monitor the power line carrier signals generated and returned by itself or monitor the power line carrier signals generated and returned by other shutdown modules.

Referring to fig. 6, in an alternative example, the communication unit MODU of the shutdown module RSD1 loads a signal onto the cable of the tandem photovoltaic module and extracts a return signal from the cable, and the controller IC operates the communication unit MODU to continuously send a signal onto the cable. The controller IC of the shutdown module RSD2 constantly monitors the signal returning from the cable by the communication unit MODU and the controller IC also monitors the degree of attenuation of the returning signal: if the attenuation of the returned signal reaches a predetermined attenuation value, the turn-off module RSD2 turns off the switch S2 to turn off the so-called photovoltaic module, thereby achieving a fast turn-off of, for example, the photovoltaic module PV 2. The present embodiment is an example of monitoring signals sent by other shutdown modules.

Referring to fig. 7, in an alternative example, the shutdown module RSD2 paired with the PV module PV2 determines whether the corresponding PV module PV2 needs to be shut down, for example, by monitoring the power line carrier signal PLC generated by the other shutdown modules RSD1 and returned through the loop. Also, the emergency personnel may disable the predetermined characteristics of the returned specified parameters of the power line carrier signal PLC by switching off the master switch in the shutdown control module CTL or by rapidly toggling the master switch S1, for example, to perform a toggling operation of switching off and on and then off. For example, the actual amplitude of the returned power line carrier signal may be lower than a preset amplitude value, and for example, the actual spectral distribution of the returned power line carrier signal may not coincide with a preset spectral distribution point. For example, the attenuation of the returned signal, for example, the returned power line carrier signal, may be brought to a predetermined attenuation value. If the emergency personnel cuts off the main control switch in the shutdown control module CTL so that the propagation path of the power line carrier signal PLC on the cable is directly disconnected, the shutdown module RSD2 cannot receive the returned power line carrier signal PLC because the propagation path of the carrier in the loop is directly cut off. The controller IC does not receive the power line carrier signal PLC within a set time period, which is likely to be a time period when the emergency personnel turns off the main control switch so that it is determined that the switch S1 needs to be turned off to turn off the photovoltaic module PV 2. The dotted line represents that the specified parameter of the returned power line carrier signal is changed after human intervention.

Referring to fig. 8, in an alternative example, shutdown control module CTL contains a noise source that can produce noise pulses NOI and the frequency of noise pulses NOI of the noise source preferably falls within the frequency range of power line carrier signal PLC. The power line carrier signal PLC is disturbed on the cable in such a way that a noise pulse NOI is actively injected. The noise-generating source is not drawn in the figure but the noise pulses NOI generated may cause the specified parameters to fail to satisfy the preset characteristics. The noise pulses NOI are injected onto the cable, for example by manual control, artificially introducing noise on the cable at the shutdown control module CTL. For example, the actual amplitude of the returned power line carrier signal may be lower than a predetermined amplitude value, and for example, the actual spectral distribution of the returned power line carrier signal may not coincide with a predetermined spectral distribution point. For example, the attenuation of the returned signal, for example, the returned power line carrier signal, may be brought to a predetermined attenuation value. Noise synchronized to the grid voltage frequency of about 50HZ to 60HZ is typically generated by switching devices operating at power frequencies, such as SCR switching devices, which generate noise and have a frequency component of about 50HZ at its harmonics. The disturbance noise generated by the motor, for example, is a disturbance with a smooth power spectrum generated by the load and the grid being out of synchronization, and is white noise. Some impulse noises, which are caused by sudden switching of the appliance or induced from the high voltage transmission transformer, are characterized by a broad frequency spectrum and a short time.

Referring to fig. 9, in an alternative example, the shutdown control module CTL includes a coupling device CPE which can absorb part of the power line carrier signal to attenuate the power line carrier signal PLC, the coupling device CPE being, for example, a capacitor or a transformer or a magnetic loop wound with a coil and sheathed on a cable. The coupling device CPE is disabled if it does not interfere with the power line carrier signal PLC to prevent the power line carrier signal PLC from being attenuated. If an attempt is made to interfere with and attenuate the power line carrier signal PLC, the coupling device CPE is introduced at the cable, absorbing at least part of the power line carrier signal PLC from the cable. The absorbed portion of the power line carrier signal can be introduced to ground or consumed directly by a load such as a resistor, for example, through the illustrated carrier shunt path PLC-BYS. In summary, a coupling device CPE is used on the cable to absorb a portion of the power line carrier signal to attenuate the power line carrier signal so that the specified parameters do not satisfy the predetermined characteristics. For example, the actual amplitude of the returned power line carrier signal may be lower than a predetermined amplitude value, and for example, the actual spectral distribution of the returned power line carrier signal may not coincide with a predetermined spectral distribution point. For example, the attenuation of the returned signal, for example, the returned power line carrier signal, may be brought to a predetermined attenuation value. Even if all the power line carrier signals PLC are absorbed and the power line carrier signals PLC cannot be received back by the shutdown module RSD2, the shutdown module RSD2 may turn off the photovoltaic module PV2 when the power line carrier signals PLC are not received within a set time period.

Referring to fig. 4, in an alternative example, in conjunction with fig. 5-9, the photovoltaic module may need to be re-enabled after being successfully shut down in certain scenarios if the alarm disappears. Assuming that the shutdown control module CTL is also provided with a controller like a shutdown module and a communication unit thereof, the shutdown control module CTL may also actively transmit a power line carrier signal to each of the shutdown modules RSD 1-RSDN. The mode of re-enabling the switched-off photovoltaic module PV1-PVN is: and power line carrier signals carrying enabling instructions are sent to the shutdown modules, the controller ICs of the shutdown modules RSD1-RSDN receive the enabling instructions through the matched communication units MODU, and the controller ICs of the shutdown modules RSD1-RSDN respond to the enabling instructions to conduct the switches S2 of the controller ICs so as to enable the photovoltaic modules PV1-PVN to be recovered to be in a switching-on state.

Referring to fig. 4, in an alternative example, in conjunction with fig. 5-9, a carrier object monitored by the controller IC of the shutdown module RSD2 is known: the power line carrier signal PLC returned via the loop is generated by the communication unit MODU operatively associated with the controller IC of the shutdown module RSD 2. When the controller IC continuously monitors the PLC signal returned from the cable through the communication unit MODU, the controller IC may continuously determine whether the specified parameter of the received PLC signal satisfies the predetermined characteristic or whether the controller IC continuously determines whether the PLC signal has not been received within a predetermined time period, only if the attenuation of the PLC signal returned from the cable exceeds a predetermined attenuation value. If not, the controller IC does not determine whether the specified parameter of the received power line carrier signal satisfies the preset characteristic, or the controller IC does not determine whether the returned power line carrier signal PLC is not received within a set time period, and naturally the photovoltaic module PV2 is not turned off. In the present embodiment, the returned power line carrier signal PLC is allowed to be generated by the shutdown module RSD2 itself: therefore, in an optional example, on the premise that the attenuation of the power line carrier signal PLC returned from the cable exceeds a preset attenuation value, the controller IC monitors whether the specified parameter of the received power line carrier signal satisfies a preset characteristic, or the controller IC determines whether the controller IC receives the power line carrier signal within a set time period, and if the specified parameter does not satisfy the preset characteristic, or the controller IC does not receive the power line carrier signal within the set time period, the photovoltaic module is turned off. The false turn-off or the false turn-on can be prevented.

Referring to fig. 6, in an alternative example, in conjunction with fig. 5-9, a carrier object monitored by the controller IC of the shutdown module RSD2 is known: the power line carrier signal PLC returned via the loop is generated by the communication unit MODU operatively associated with the controller IC of the shutdown module RSD 1. When the controller IC continuously monitors the power line carrier signal PLC returned from the cable via the communication unit MODU, the controller IC continues to determine whether a predetermined parameter of the so-called received power line carrier signal meets a predetermined characteristic or whether the controller IC continues to determine whether the returned power line carrier signal PLC has not been received within a predetermined time period, provided that the attenuation of the power line carrier signal PLC returned from the cable exceeds a predetermined attenuation value. If not, the controller IC does not determine whether the specified parameter of the received power line carrier signal satisfies the preset characteristic, or the controller IC does not determine whether the returned power line carrier signal PLC is not received within a set time period, and naturally the photovoltaic module PV2 is not turned off. In this embodiment, the returned power line carrier signal PLC is allowed to be generated by the other shutdown module RSD 1: therefore, in an optional example, on the premise that the attenuation of the power line carrier signal PLC returned from the cable exceeds a preset attenuation value, the controller IC monitors whether the specified parameter of the received power line carrier signal satisfies a preset characteristic, or the controller IC determines whether the controller IC receives the power line carrier signal within a set time period, and if the specified parameter does not satisfy the preset characteristic, or the controller IC does not receive the power line carrier signal within the set time period, the photovoltaic module is turned off. The false turn-off or the false turn-on can be prevented. Attention is paid to attenuation judgment of the power line carrier signal, signal characteristics of an initial power line carrier signal sent by the turn-off module need to be known, and an attenuation result can be accurately obtained by comparing a returned power line carrier signal with the initial power line carrier signal. In addition, the voltage and current output by the photovoltaic module are influenced by comprehensive factors such as illumination radiation intensity, ambient temperature, whether shielding, shielding degree, aging state of the photovoltaic module and the like, the comprehensive factors are dynamically changed at any time, and the instability of the voltage and current of a power line carrier signal or a periodic signal or a non-periodic signal transmission channel and natural noise mixed in the channel can cause that a turn-off module is difficult to discriminate natural noise and external signals and calculate the attenuation of the signals naturally. It is preferable that the shutdown module monitors the signal generated and returned by itself or monitors the signal generated and returned by other shutdown modules, and the error rate of signal attenuation calculation can be reduced to the lowest level, namely, the error shutdown rate or the error connection rate of the photovoltaic module is reduced.

Referring to fig. 6, in an alternative example, in connection with fig. 4-9, a shutdown control module CTL is provided in the loop and the photovoltaic modules PV1-PVN are shut down at said shutdown control module CTL in such a way that: and adjusting the impedance in the loop so as to change the attenuation degree of the power line carrier signal PLC in the loop, so that the specified parameters cannot meet the preset characteristics. For example, to allow the impedance value in the loop to be adjusted to a greater extent with greater attenuation of the power line carrier signal PLC. An alternative example is to introduce a capacitance, resistance, inductance, etc. on the cable at the shutdown control module CTL to change the loop impedance, and to remove these impedance-affecting electronic components from the cable, so-called capacitance, resistance, inductance, etc. to change the loop impedance. In fact, fig. 10-11, which will be described later in this application, are typical examples of adjusting the impedance in a loop.

Referring to fig. 6, in an alternative example, it is provided that the communication unit is operated by the controller IC of the leading or first photovoltaic module PV1 of the plurality of photovoltaic modules PV1-PVN to continuously transmit the power line carrier signal, while the controller IC of each photovoltaic module PV1-PVN is provided to continuously monitor the power line carrier signal returned from the cable through the communication unit. If the controller of the PV module PV1-PVN monitors that the specified parameter of the returned power line carrier signal does not satisfy the predetermined characteristic, or the controller of the PV module PV1-PVN does not receive the power line carrier signal within a set period of time, the PV module PV1-PVN opens the respective switch S2 to turn off the module PV 1-PVN. Note that in this example, the power line carrier signal from the controller IC operation communication unit of the first stage PV1 can be transmitted through the positive bus to the inverter and then transmitted back to each of the photovoltaic modules PV1-PVN through the negative bus, i.e., back through the loop. In the present example, the power line carrier signal sent by the shutdown module RSD1 of the first-level PV1 is required to be transmitted to the inverter and then returned to the multi-level PV modules PV1-PVN along a loop. The carrier signal crosstalk among the photovoltaic modules in the battery pack string can be prevented, and the carrier signal crosstalk among the photovoltaic modules easily causes mistaken turn-off or mistaken turn-on.

Referring to fig. 6, in an alternative example, the controller IC of the last or nth PV module PV N of the PV modules 1-PVN continuously transmits the power line carrier signal while the controller IC of each PV module 1-PVN continuously monitors the power line carrier signal returned from the cable via the communication unit. If the controller of the PV module PV1-PVN monitors that the specified parameter of the returned power line carrier signal does not satisfy the predetermined characteristic, or the controller of the PV module PV1-PVN does not receive the power line carrier signal within a set period of time, the PV module PV1-PVN opens the respective switch S2 to turn off the module PV 1-PVN. Note that in this example, the controller IC of the nth stage PV module PVN operates the communication unit to send out the power line carrier signal that propagates through the negative bus to the inverter and then back through the positive bus to the PV1-PVN stages, i.e., through the loop. In the embodiment, the power line carrier signal sent by the shutdown module RSDN of the last stage, i.e., the nth stage photovoltaic module PVN, is required to be transmitted to the inverter and then returned to the multilevel photovoltaic modules PV1-PVN along a loop. And the carrier signal crosstalk among all photovoltaic modules in the battery pack string is prevented. The positive and negative busbars are also cables in nature.

Referring to fig. 6, in an alternative example, in conjunction with fig. 4-12, the controller operates the communication unit MODU to continuously send a signal (signal) onto the cable, which in the foregoing context is a power line carrier signal PLC as a typical example to illustrate the working mechanism of the shutdown module. In alternative embodiments, the PLC is replaced by other types of periodic signals or non-periodic signals, so the signal (signal) can be selected from the PLC signals, the periodic signals or non-periodic signals, and the signal is not limited to a specific type.

Referring to fig. 9, in an alternative example, the controller IC of the turn-off module RSD is also used to control the opening or closing of the diverter switch S2 provided for the photovoltaic module: the controller IC receives the enabling instruction through the communication unit MODU, for example, the enabling instruction is uploaded to the controller IC from the cable through the power line carrier signal by receiving the power line carrier signal through the power line carrier demodulator of the matched communication unit MODU. The coupling element COP senses a carrier signal carrying an enable command from the on-cable shutdown control module CTL and further transfers the sensed power line carrier signal to the so-called communication unit MODU. The communication unit MODU decodes the enabling instruction from the power line carrier carrying the enabling instruction and sends the enabling instruction to the controller IC. The communication unit MODU may receive an external instruction using a conventional communication method such as wireless communication, in addition to wired communication using a power line carrier. Note that in some alternative examples the communication unit may be built directly into the controller IC, i.e. the controller IC is directly integrated with the communication unit.

Referring to fig. 9, an enable command to the controller IC requests the photovoltaic module to be restarted, and the controller IC turns ON (ON) the switch S2 in response to the enable command to restart the photovoltaic module. The turn-off module RSD1-RSDN is used for realizing a quick turn-off function of the photovoltaic module. Shutdown (shutdown) and re-connection (re-connection) are two important conditions that a photovoltaic module can meet the terms of the industry with respect to NEC 690.12. It is not a requirement that the photovoltaic module be returned to the on state in many instances, as photovoltaic power plants typically require rapid shut down of the module but the module may not be required to be returned to the on state in the event of a fire. The above embodiments of the present application can better cope with emergency situations of the photovoltaic power station, such as fire, etc., and can actively and rapidly turn off the photovoltaic module to cut off the direct current. The power line carrier signal which is used for judging whether the photovoltaic component is cut off by the turn-off module is originated from the turn-off module of the multi-stage photovoltaic component and is not originated from other power line carrier signal transmitting devices, and the design has great advantages in both cost consideration and reliability consideration of turn-off. The disadvantage of using other power line carrier signal transmitting devices to control the turn-off module is as follows: the cost is significantly increased; various parameter information of power line carrier signals sent by other power line carrier signal transmitting devices is hidden for the turn-off module, so that the turn-off module is likely to make misjudgment in the stage of judging whether to turn off the photovoltaic module. Since the loop not only has the power line carrier signals sent by other power line carrier signal sending devices, but also has various natural noises, the turn-off module can respond to the power line carrier signals sent by other power line carrier signal sending devices, and naturally, the turn-off module can respond to various noises naturally existing in the loop to turn off or turn on the photovoltaic module by mistake. The signal emitted by any shutdown module is known to each shutdown module in terms of its parameters rather than being concealed. It is noted that the energy of the direct current bus is supplied to the inverter to perform the inversion conversion operation from direct current to alternating current, and the noise harmonic pollution of the inverter to the direct current bus is almost inherent and unavoidable, and the application can better avoid the negative disadvantages which are easy to cause misoperation.

Referring to fig. 10, the shutdown control module CTL may be referred to as a master control module, where it may be decided whether to shut down the multilevel photovoltaic modules PV 1-PVN. Alternative examples of shutdown control module CTL: the cable is provided with an inductance element L1, a capacitance element C1, and a relay S3. The inductance element L1 is connected to the cable so that the inductance element L1 is present in the loop. The capacitor C1 is connected in series with the relay S3 and then connected in parallel with the inductor L1, and the relay is turned off, for example, the relay S3 is turned off, so that the attenuation of the returned signal reaches a predetermined attenuation value. Although the relay allows a high voltage-resistant dc relay, it is preferable to use a low-signal relay which is relatively cost-effective.

Referring to fig. 11, an alternative example of the shutdown control module CTL: an attenuator ATT is provided on the cable and is claimed to be used to adjust the degree of attenuation of the return signal in the loop. An attenuator (attenuator) is an electronic component that can provide a signal attenuation function, and can adjust the magnitude of a signal in a loop, read the attenuation value of a tested loop, and adjust the impedance matching of the whole loop. The attenuation degree of the signal is adjusted in a mode of adjusting the attenuation of the attenuator ATT to the signal, so that the attenuation degree of the returned signal can reach a preset attenuation value.

Referring to fig. 12, an example of fast turn-off of a photovoltaic module is supported: each of the multilevel PV modules PV1-PVN is configured with a voltage converter, and the output voltages of the voltage converters corresponding to the multilevel PV modules PV1-PVN are required to be superimposed on the dc bus and thereby used as the bus voltage, when the voltage converters are connected in series with each other. For example, the first photovoltaic module PV1 is provided with a voltage converter 200, and the so-called voltage converter 200 converts the electrical energy extracted from the corresponding one of the photovoltaic modules PV1 into its own output power and provides an output voltage V_O1-1. For example, the second photovoltaic module PV2 is provided with a voltage converter 200, and the so-called voltage converter 200 converts the electrical energy extracted from the corresponding one of the photovoltaic modules PV2 into its own output power and provides an output voltage V_O2-2. For example, the nth photovoltaic module PVN is configured with a voltage converter 200, and the so-called voltage converter 200 converts the electric energy extracted from the corresponding one of the photovoltaic modules PVN into its own output power and provides an output voltage V_ON-N. The bus voltage, that is, the output voltages of the voltage converters 200 are added, and the output voltages of the plurality of voltage converters connected in series are added and supplied to one inverter INVT, so that a loop is formed between the plurality of voltage converters and the inverter connected in series. Signals sent by the turn-off module of each stage of photovoltaic module are transmitted to the inverter and then transmitted to the inverterAlong a loop back to the plurality of voltage converters or a signal back to the plurality of turn-off modules RSD 1-RSDN. Note that the solutions described above with respect to fig. 2-11 are equally applicable to the embodiment of fig. 12.

Referring to fig. 12, each voltage converter performs voltage reduction, voltage increase, or voltage reduction on the output voltage of a corresponding photovoltaic module, and then outputs the output voltage. The voltage converter 200 configured as the first stage photovoltaic module PV1 is used to perform voltage conversion of an initial voltage output by a so-called first stage photovoltaic module PV1, the voltage conversion including step-down voltage conversion or step-up voltage conversion or step-down voltage conversion. The controller IC of the shutdown module RSD1 may be used to operate the so-called voltage converter 200 to perform voltage conversion such as buck, boost, or buck-boost, and the voltage converter 200 may be a buck converter, a boost converter, a buck-boost converter, or a buck-boost converter, as the switching power supply. Even in an alternative example, each voltage converter is used for setting the current and the voltage output by the corresponding photovoltaic module at the maximum power point, so that the power optimization and the maximum power tracking of the photovoltaic module are realized. The voltage converter 200, such as the shutdown module RSD1, is used to set the current and voltage output by the corresponding first stage photovoltaic module PV1 at the maximum power point.

Referring to fig. 12, in an alternative example, the voltage converter 200 of the nth stage pv device PVN is configured to perform voltage conversion on an initial voltage output by the so-called nth stage pv device PVN, wherein the voltage conversion includes step-down voltage conversion or step-up voltage conversion or step-down voltage conversion. The controller IC of the turn-off module RSDN may be configured to operate the so-called voltage converter 200 to perform voltage conversion such as buck, boost or buck-boost, and the voltage converter 200 may be a buck converter or a boost converter or a buck-boost converter as the switching power supply. Even in an alternative example, each voltage converter is used for setting the current and the voltage output by the corresponding photovoltaic module at the maximum power point, so that the power optimization and the maximum power tracking of the photovoltaic module are realized. The voltage converter 200, such as the shutdown module RSDN, is used to set the current and voltage output by the nth stage pv module PVN corresponding thereto at the maximum power point.

Referring to fig. 12, in an alternative example, the shutdown module RSD1 paired with the PV module PV1 determines whether the corresponding PV module PV1 needs to be shut down, for example, by monitoring the power line carrier signal PLC generated by the other shutdown modules RSDN and returned through the loop. Also, the emergency personnel may disable the predetermined characteristics of the returned specified parameters of the power line carrier signal PLC by switching off the master switch in the shutdown control module CTL or by rapidly toggling the master switch S1, for example, to perform a toggling operation of switching off and on and then off. For example, the actual amplitude of the returned power line carrier signal may be made lower than a preset amplitude value. For example, the actual spectral distribution of the returned power line carrier signal may not coincide with the preset spectral distribution point. For example, the attenuation of the returned signal, for example, the returned power line carrier signal, may be brought to a predetermined attenuation value. If the emergency personnel cuts off the main control switch in the shutdown control module CTL so that the propagation path of the power line carrier signal PLC on the cable is directly disconnected, the shutdown module RSD2 cannot receive the returned power line carrier signal PLC because the propagation path of the carrier in the loop is directly cut off. The controller IC does not receive the power line carrier signal PLC within a set time period, which is likely to be a time period when the emergency personnel switches off the main control switch, so that it is determined that the turn-off module RSD1 needs to be turned off to turn off the photovoltaic module PV 1.

Referring to fig. 12, in an alternative example, the shutdown module RSD1 paired with the PV module PV1 determines whether the corresponding PV module PV1 needs to be shut down, for example, by monitoring the power line carrier signal PLC generated by the shutdown module RSD1 itself and returned through the loop. For example, by shutting down the operation of the control module CTL, the given parameters of the returned power line carrier signal PLC cannot satisfy the preset characteristics. For example, the actual amplitude of the returned power line carrier signal may be lower than a preset amplitude value, and for example, the actual spectral distribution of the returned power line carrier signal may not coincide with a preset spectral distribution point. For example, the attenuation of the returned signal, for example, the returned power line carrier signal, may be brought to a predetermined attenuation value. If the emergency personnel cuts off the main control switch in the shutdown control module CTL so that the propagation path of the power line carrier signal PLC on the cable is directly disconnected, the shutdown module RSD2 cannot receive the returned power line carrier signal PLC because the propagation path of the carrier in the loop is directly cut off. The controller IC does not receive the power line carrier signal PLC within a set time period, which is likely to be a time period when the emergency personnel switches off the main control switch, so that it is determined that the turn-off module RSD1 needs to be turned off to turn off the photovoltaic module PV 1.

Referring to fig. 12, in an alternative example, the controller IC of the shutdown module RSD1 is further configured to monitor the attenuation of the returned signal, and if the predetermined attenuation is reached, the controller IC may adjust the output voltage of the low voltage converter 200 or the output power of the low voltage converter 200. The controller IC of the shutdown module RSDN is further configured to monitor an attenuation degree of the returned signal, and if the attenuation degree reaches a predetermined attenuation value, the controller IC may adjust the output voltage of the low voltage converter 200 or adjust the output power of the low voltage converter 200. When the voltage converters 200 of the shutdown modules RSD1-RSDN all turn down their output voltages and output a low voltage level, the bus voltage obtained by adding the output voltages of the voltage converters 200 corresponding to a plurality of shutdown modules may drop rapidly from several hundred volts to around a zero value, and the bus voltage is usually allowed to drop to a safe voltage range of several volts to several tens of volts. The controller IC steps down the output voltage of the voltage converter 200, essentially equivalent to achieving a fast turn-off of the photovoltaic module. The attenuation degree of the return signal is much greater than the output voltage of the voltage converter 200 in the case where the attenuation degree of the return signal reaches the preset attenuation value. For example, the output voltage of the voltage converter 200 has a first voltage range when the attenuation degree of the return signal does not reach the predetermined attenuation value, and the output voltage of the voltage converter 200 has a second voltage range when the attenuation degree of the return signal reaches the predetermined attenuation value, and it is obvious that the first voltage range is much larger than the second voltage range. The second voltage range is arranged as close as possible to zero. The embodiment can enable the photovoltaic system to realize a quick turn-off function so as to reduce the electric shock hazard to emergency treatment personnel and meet the terms of NEC 690.12.

Referring to fig. 11, in an alternative example, in connection with fig. 2 to 12, the communication unit MODU is configured to load the power line carrier signal it generates onto the cable that is concatenated with the multilevel photovoltaic modules PV1-PVN and to extract the returned power line carrier signal from the cable. The controller IC operates said communication unit MODU to continuously transmit the power line carrier signal having the preset characteristic. The controller IC continuously monitors the power line carrier signal returned from the cable by means of said communication unit MODU. The controller IC monitors whether the specified parameter of the received power line carrier signal satisfies the preset characteristic and turns off the switch S2 to turn off the photovoltaic module if the specified parameter does not satisfy the preset characteristic or the controller IC does not receive the power line carrier signal within a set time period. In an alternative example, the controller IC also monitors the degree of attenuation of the returned signal, e.g., the returned power line carrier signal, and opens the switch S2 to turn off the photovoltaic module if the degree of attenuation of the returned power line carrier signal reaches a preset attenuation value.

Referring to fig. 12, in an alternative example, in conjunction with fig. 2 to 11, the communication unit MODU is configured to load and inject the power line carrier signal generated by the communication unit MODU onto the cable that connects the plurality of voltage converters 200 in series and to extract the returned power line carrier signal from the cable. The controller IC operates said communication unit MODU to continuously transmit the power line carrier signal having the preset characteristic. The controller IC continuously monitors the power line carrier signal returned from the cable by means of said communication unit MODU. The controller IC monitors whether the received specified parameter of the power line carrier signal satisfies the preset characteristic and reduces the output voltage of the voltage converter 200 if the specified parameter does not satisfy the preset characteristic or the controller IC does not receive the power line carrier signal within a set time period, so as to be equivalent to turning off the photovoltaic module. The controller IC monitors the attenuation degree of the return signal, such as the returned power line carrier signal, and if the attenuation degree of the returned power line carrier signal reaches a preset attenuation value, the output voltage of the voltage converter 200 is reduced, which is equivalent to turning off the photovoltaic module. The calculation of the attenuation values of the signals in the present application can be implemented according to the attenuation calculation methods of the prior art. The signal sent by the turn-off module is directly captured locally by each turn-off module without a loop and generates a turn-off judgment result, which is one of the main sources of misjudgment.

While the present invention has been described with reference to the preferred embodiments and illustrative embodiments, it is to be understood that the invention as described is not limited to the disclosed embodiments. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above description. It is therefore intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention. Any and all equivalent ranges and contents within the scope of the claims should be considered to be within the intent and scope of the present invention.

Claims

1. A shutdown module for rapid shutdown of a photovoltaic module, comprising:

the controller controls the on or off of the selector switch;

the diverter switch is opened to turn off the photovoltaic module.

2. A shutdown module as claimed in claim 1, characterized in that:

the signal is one of a power line carrier signal, a periodic signal, and a non-periodic signal.

3. A shutdown module as claimed in claim 1, characterized in that:

4. A shutdown module as claimed in claim 1, characterized in that:

5. A shutdown module as claimed in claim 1, characterized in that:

the attenuation degree of the signal reaches a preset attenuation value, including the condition of attenuation to zero point decibel, namely the condition that the controller does not receive the returned signal.

6. A shutdown module as claimed in claim 1, characterized in that:

and an attenuator is arranged on the cable, and the attenuator is used for adjusting the attenuation degree of the signal so as to enable the attenuation degree of the returned signal to reach a preset attenuation value.

7. A shutdown module as claimed in claim 1, characterized in that:

and a main control switch is arranged on the cable, and the propagation path of the signal is directly disconnected in a mode of disconnecting the main control switch, so that the controller cannot receive the returned signal.

8. A shutdown module as claimed in claim 1, characterized in that:

and interfering the signal on the cable in a manner of actively injecting extra noise pulses, so that the returned signal is attenuated to a preset attenuation value.

9. A shutdown module as claimed in claim 1, characterized in that:

and absorbing part of the signal on the cable by using a coupling device to weaken the signal, so that the returned signal is attenuated to a preset attenuation value.

10. A shutdown module as claimed in claim 1, characterized in that:

11. A shutdown module as claimed in claim 1, characterized in that:

the mode of re-enabling the shut-down photovoltaic module is:

12. A shutdown module as claimed in claim 3 or 4, characterized in that:

the output voltages of the multi-stage photovoltaic modules are superposed and then are supplied to an inverter;

13. A method of shutting down a photovoltaic module, comprising:

14. The method of claim 13, wherein:

15. The method of claim 14, wherein:

16. The method of claim 14, wherein:

additional noise pulses are actively injected into the cable to interfere with the signal, or a coupling device is used on the cable to absorb a portion of the signal to attenuate the signal so that the returned signal is attenuated to a predetermined attenuation value.

17. The method of claim 14, wherein:

a turn-off control module with an attenuator connected to the cable is arranged in the loop;

18. The method of claim 13, wherein:

19. The method of claim 13, wherein:

20. A method of shutting down a photovoltaic module, comprising:

a loop is formed between the multi-stage photovoltaic module and the inverter;

the turn-off method comprises the following steps:

21. The method of claim 20, wherein:

22. The method of claim 20, wherein:

23. The method of claim 20, wherein:

24. A shutdown module for rapid shutdown of a photovoltaic module, comprising:

a controller for operating the voltage converter to perform voltage conversion;

the controller adjusts the output voltage of the voltage converter down.

25. A shutdown module as claimed in claim 24, wherein:

26. A shutdown module as claimed in claim 24, wherein:

27. A shutdown module as claimed in claim 24, wherein:

28. A shutdown module as claimed in claim 24, wherein: