DE102019205701A1 - Inverters, especially micro solar inverters - Google Patents

Abstract

Inverters, in particular micro solar inverters, designed for attachment to a photovoltaic panel and for converting the direct current generated by this photovoltaic panel into alternating current with a device for wireless communication, the device being designed for wireless communication, a direct data connection to another inverter and to send data directly to the other inverter and to receive data directly from the other inverter.

Description

The invention relates to an inverter designed for attachment to a photovoltaic panel and for converting the direct current generated by this photovoltaic panel into an alternating current. Inverters that are assigned to exactly one photovoltaic panel and only convert its direct current are known as micro solar inverters.

Photovoltaic systems play an increasingly important role in the supply of electrical energy. A photovoltaic system comprises several solar panels (= photovoltaic modules or PV panels) that generate electrical energy when exposed to sunlight. The solar panels are typically set up essentially next to one another, for example by being arranged in a rectangular pattern on a house roof.

There are several options for the electrical connection. The solar panels can be interconnected in one or more series, whereby a series is referred to as a "string". A converter is then provided for each string or for the entire photovoltaic system, which converts the resulting direct voltage from the solar panels into alternating voltage. While the power electronics are advantageously bundled in this embodiment, the power of a string depends on each of the solar panels being optimally illuminated. Shading or other influences on one or a few solar panels deteriorate the performance of the string disproportionately.

An alternative is the use of so-called optimizers (or optimizers), which are DC / DC converters and are arranged on each of the solar panels and carry out so-called maximum power point tracking (MPP tracking) there. As a result, performance deficits of a solar panel do not have a negative effect on other solar panels of the same string, but additional power electronics are required on each panel.

In a further possibility, so-called micro solar inverters (English solar micro inverter or microinverter) are used. These are also arranged on each of the solar panels and convert the generated direct voltage into alternating voltage. The power electronics are therefore decentralized and the overall or string converter can be omitted. The micro solar inverters also perform MPP tracking. This results in further advantages. For example, the micro solar inverters allow you to work with significantly lower voltage. Conversely, the increased number of individual power electronics components results in the disadvantage of increased effort in commissioning and networking the micro solar inverters.

It is the object of the present invention to specify an inverter designed for attachment to a photovoltaic panel and for converting the direct current generated by this photovoltaic panel, which inverter reduces or solves the problem mentioned at the beginning. This object is achieved by an inverter with the features of claim 1.

The inverter according to the invention is in particular a micro solar inverter and is designed to be attached to a photovoltaic panel and to convert the direct current generated by this photovoltaic panel into an alternating current. The inverter comprises a device for wireless communication, the device for wireless communication being designed to set up a direct data connection to a further inverter and to use this to send data directly to the further inverter and to receive data directly from the further inverter.

The inverter is therefore intended to convert only the direct current of a single PV panel and is therefore preferably connected directly to it. A direct data connection is a connection that works without going through an access point, router or other central device. A direct data connection also means that a successful data exchange is made possible, which is not limited to the physical reception of the signals, but includes the interpretation, storage and processing of the exchanged information.

The inverter according to the invention advantageously enables a wireless exchange of data and information between the inverters without the need for an infrastructure in the form of existing routers or similar devices. A suitable electrical infrastructure for using a powerline communication connection is also not required. Rather, the inverters connect to one another. Due to the wireless connection, the arrangement of the inverters and the number is irrelevant. This makes it much easier to pass on information in a new PV system and avoids the disadvantage of micro solar inverters and the larger number of devices.

• - Die Einrichtung zur drahtlosen Kommunikation kann ausgestaltet sein, als direkte Datenverbindung eine WLAN-Verbindung zu dem weiteren Wechselrichter herzustellen. Der WLAN-Standard ist weit verbreitet und ermöglicht, marktübliche kleine und günstige Module für die Kommunikation per WLAN zu verbauen. Weiterhin ist so auch der drahtlose Kontakt mit Standardgeräten wie Netzwerk-Routern ohne weitere Hardware möglich.
• - Die Einrichtung zur drahtlosen Kommunikation kann ausgestaltet sein, ein vermaschtes drahtloses Netzwerk mit dem weiteren Wechselrichter auszubilden. Bevorzugt werden weitere Datenverbindungen zu weiteren Wechselrichtern und/oder Netzwerk-Routern aufgebaut. Dadurch entsteht vorteilhaft ein Kommunikationsnetzwerk, in dem die verbundenen Wechselrichter mit allen anderen verbundenen Geräten Daten austauschen können. Das gilt speziell auch dann, wenn einige der betroffenen Geräte alleine keine Verbindung aufbauen könnten, weil beispielsweise der Abstand zu groß ist oder die Dämpfung der Signale durch zwischenliegende Wände oder Decken zu intensiv ist. Kann also einer der Wechselrichter keine direkte Verbindung zu einem Netzwerk-Router aufbauen, ein anderer Wechselrichter aber schon, dann ermöglicht das vermaschte Netzwerk eine Datenverbindung zwischen dem betroffenen Wechselrichter und dem Netzwerk-Router.

Advantageous configurations of the converter according to the invention and of the operating method according to the invention emerge from the claims dependent on claim 1. The embodiment according to claim 1 and claim 7 with the features of one of the subclaims or are preferably also combined with those from several subclaims. Accordingly, the following features can also be provided:

• The device for wireless communication can be designed to establish a WLAN connection to the further inverter as a direct data connection. The WLAN standard is widespread and makes it possible to install small, inexpensive modules available on the market for communication via WLAN. Furthermore, wireless contact with standard devices such as network routers is also possible without additional hardware.
• The device for wireless communication can be designed to form a meshed wireless network with the further inverter. Further data connections to further inverters and / or network routers are preferably established. This advantageously creates a communication network in which the connected inverters can exchange data with all other connected devices. This also applies in particular if some of the affected devices cannot establish a connection on their own, for example because the distance is too great or the attenuation of the signals by walls or ceilings between them is too intense. If one of the inverters cannot establish a direct connection to a network router, but another inverter can, then the meshed network enables a data connection between the inverter concerned and the network router.

For this purpose, the device for wireless communication can be designed to receive data from the further inverter to a network router from the further inverter and to forward it to the network router, and to receive data from the network router to the further inverter are to be received by the network router and forwarded to the other inverter. It is also possible to forward data intended for the network router to other inverters, which in turn can reach the network router.

• - Die Einrichtung zur drahtlosen Kommunikation kann ausgestaltet sein, bei Empfang einer Anfrage-Nachricht vom weiteren Wechselrichter bestimmte gespeicherte Daten an den weiteren Wechselrichter zu senden. Bei den gespeicherten Daten handelt es sich bevorzugt um Daten, die der Konfiguration des Wechselrichters dienen. Dabei kann es sich beispielsweise um Netzwerkzugangsdaten handeln. Es kann sich aber auch um Konfigurationsdaten für die elektrische Konfiguration für den Wechselrichter handeln. Diese Daten werden an den weiteren Wechselrichter übermittelt, wenn das sinnvoll ist, also wenn eine entsprechende Anfrage-Nachricht vom weiteren Wechselrichter eingeht.

It can be useful if the connection is only extended to inverters of the same type. This prevents the network from including unwanted third-party devices and enables them to access the inverters and the network router. This increases the security of the network formed.

• The device for wireless communication can be designed to send certain stored data to the further inverter upon receipt of an inquiry message from the further inverter. The stored data is preferably data that is used to configure the inverter. This can be, for example, network access data. However, it can also be configuration data for the electrical configuration for the inverter. This data is transmitted to the other inverter if it makes sense, i.e. when a corresponding request message is received from the other inverter.

This makes it possible that the configuration data does not have to be entered manually in the additional inverter. In a new PV system, it is sufficient for commissioning if one of the inverters is configured. The configuration is then automatically passed on to the inverters that have not yet been configured without having to perform another manual step, i.e. without further human intervention. This compensates for the disadvantage of the micro solar inverters that there is a large number of inverters that need to be commissioned. A later expansion of a photovoltaic system with additional photovoltaic panels or the replacement of a PV panel or the inverter is also significantly simplified.

• - Dabei kann der Wechselrichter ausgestaltet sein zur Festlegung eines Inbetriebnahme-Zeitraums. Die Einrichtung zur drahtlosen Kommunikation ist dann ferner ausgestaltet, außerhalb des Inbetriebnahme-Zeitraums bei Empfang der Anfrage-Nachricht die gespeicherten Daten nicht zu senden. Mit anderen Worten findet eine Übermittlung der gespeicherten Daten nur innerhalb des Inbetriebnahme-Zeitraums statt. Ebenso ist es möglich, dass eine Speicherung solcher Daten nach Empfang nur innerhalb des Inbetriebnahme-Zeitraums stattfindet. Der Inbetriebnahme-Zeitraum kann beispielsweise dadurch begrenzt werden, dass Konfigurationsdaten vom Wechselrichter empfangen und verwendet werden. Hat der Wechselrichter einmal solche Daten empfangen, werden diese nicht mehr überschrieben. Es ist auch möglich, dass nach der Speicherung von Konfigurationsdaten nur noch das Versenden der Konfigurationsdaten möglich ist, sodass ein fälschliches oder absichtliches Überschreiben der Konfiguration nicht möglich ist.
• - Es ist auch möglich, dass das Versenden der Konfigurationsdaten ausschließlich durch eine manuelle Ansteuerung ausgelöst wird. Das kann beispielsweise von einem Tablet oder Smartphone aus erfolgen, das bei der Inbetriebnahme verwendet wird. Dadurch wird sichergestellt, dass sicherheitsrelevante Daten wie Netzwerkschlüssel nicht von Fremdgeräten leicht abgerufen werden können. Es ist auch möglich, dass durch eine manuelle Ansteuerung beispielsweise von einem Tablet oder Smartphone aus ein Wechselrichter dazu eingerichtet werden kann, die Konfigurationsdaten zu ändern oder zu entfernen. Dadurch können Änderungen in der Anlage oder im angeschlossenen Netzwerk, beispielsweise eine Passwortänderung, auch nach der Inbetriebnahme in die Wechselrichter übernommen werden. Gleichzeitig wird aber verhindert, dass die Daten allzuleicht verändert werden.

The network access data and / or configuration data transmitted in this way for the electrical configuration for the inverter are then expediently received by the further inverter and stored and used for its own configuration.

• - The inverter can be designed to define a commissioning period. The device for wireless communication is then also designed not to send the stored data when the request message is received outside of the commissioning period. In other words, the stored data is only transmitted within the commissioning period. It is also possible that such data are only saved within the commissioning period after receipt. The commissioning period can be limited, for example, by receiving and using configuration data from the inverter. Once the inverter has received such data, it is no longer overwritten. It is also possible that after the configuration data has been saved, only the configuration data can be sent, so that an incorrect or deliberately overwriting the configuration is not possible.
• - It is also possible that the sending of the configuration data is only triggered by manual activation. This can be done, for example, from a tablet or smartphone that is used during commissioning. This ensures that security-relevant data such as network keys cannot be easily accessed by third-party devices. It is also possible that an inverter can be set up to change or remove the configuration data through manual control, for example from a tablet or smartphone. This means that changes in the system or in the connected network, such as a password change, can also be adopted in the inverter after commissioning. At the same time, however, it prevents the data from being changed too easily.

Further advantages and features can be found in the following description of exemplary embodiments with reference to the figures. In the figures, the same reference symbols denote the same components and functions.

• 1 ein Photovoltaik-System mit PV-Panels in einem großen räumlichen Abstand von einem mit dem Internet verbundenen Router,
• 2 die Inbetriebnahme eines PV-Panels des Photovoltaik-Systems,
• 3 die Inbetriebnahme eines weiteren PV-Panels des Photovoltaik-Systems.

Show it:

• 1 a photovoltaic system with PV panels at a large spatial distance from a router connected to the Internet,
• 2 the commissioning of a PV panel of the photovoltaic system,
• 3 the commissioning of another PV panel of the photovoltaic system.

1 shows schematically a section from a photovoltaic system 10 with PV panels 121 ... 124 . Each of the PV panels 121 ... 124 has its own inverter 131 ... 134 on. The AC voltage outputs of the inverters 131 ... 134 are related to what is in 1 is not shown. As a result, the electricity generated is fed into a building network, for example.

Furthermore shows 1 a network router 15th that provides a WLAN network. The network router 15th is connected to the internet 17th and provides other devices connected to the network router 15th are in a data connection, access to the Internet 17th to disposal.

With the photovoltaic system 10 are a first and a second PV panel 121 , 122 Spatially arranged so that the respective associated inverter 131, 132 itself has a direct WLAN connection with the network router 15th can build. This allows the inverter 131 , 132 a connection to the Internet 17th without having to rely on additional equipment or other infrastructure.

A third and a fourth PV panel 123 , 124 are at a greater spatial distance from the network router 15th than the first two PV panels 121 , 122 . The inverters 133 , 134 of the third and fourth PV panels 123 , 124 are therefore not able to establish a WLAN connection with the network router in this exemplary embodiment 15th because the WiFi signal is weakened too much by the distance and possibly also by building walls, ceilings and other obstacles.

Therefore, the inverter provides 133 of the third PV panel 123 a direct data connection to the inverter 131 of the first PV panel 121 here. A direct data connection means that the data connection is established without the detour via a central infrastructure element such as a router or access point and the direct data exchange between the inverters 131 , 133 of the two affected PV panels 121 , 123 allowed.

The direct data connection is not only used to transfer data between the two inverters 131 , 133 can be exchanged, but data packets can also be forwarded. The direct data connection enables access for the inverter 133 of the third PV panel 123 to the network router 15th and to the internet 17th by sending the data packets between internet 17th and the inverter 133 of the third PV panel 123 through the inverter 131 of the first PV panel 121 to get redirected.

The inverter 134 of the fourth PV panel 124 in turn provides a direct data connection to the inverter 133 of the third PV panel 123 here. This also gives the inverter 134 of the fourth PV panel 124 access to the network router 15th and to the internet 17th .

Even the inverter 132 of the second PV panel 132 can establish a direct data connection to the inverter 131 of the first PV panel 121 Establish even if the inverter 132 already directly with the network router 15th connected is.

The inverters 131 ... 134 the PV panels 121 ... 124 So create a so-called mesh network, in which the network nodes not only with a central infrastructure element such as a router or access point, but partially or completely with each other are connected. This also gives such network nodes access, for example, to the Internet 17th allows that itself does not connect to a network router 15th can produce.

The direct data connection is wireless and can also be a WiFi connection like the WiFi connection to the network router 15th . Alternatively or additionally, however, other forms of wireless communication such as Bluetooth, ZigBee or Thread can also be used to create the meshed network.

A situation that occurs when commissioning a PV panel 121 ... 124 of the photovoltaic system is in 2 shown. Commissioning takes place with the help of a tablet PC 22nd , on the configuration data for the inverters 131 ... 134 are stored. Such configuration data can be, for example, access data to a wireless network such as that from the network router 15th generated WLAN, access data to one on the Internet 17th accessible cloud storage or data via the photovoltaic system 10 such as the number of installed PV panels 121 ... 124 or electrical configuration data such as a maximum power to be delivered. These data can be stored in the tablet PC 22nd be stored or by a user on site in the tablet PC 22nd can be entered.

In the example given here, commissioning takes place for the second PV panel 122 and its inverter 132 . Between the tablet PC 22nd and the inverter 132 a direct data connection is established. This allows the tablet PC 22nd to part of the meshed network of the inverters 131 ... 134 will. It is also possible that the tablet PC 22nd provides a WLAN access point that establishes a WLAN connection to the inverter 132 allowed. For example, if the mesh network uses Bluetooth, it would be the tablet PC 22nd not part of the meshed network, but still with the inverter 132 connected for data exchange.

A transmission now takes place over the existing connection 24 the configuration data from the tablet PC 22nd to the inverter 132 instead of. The configuration data are saved there in a memory area provided for this purpose. The inverter 132 thus receives the necessary data for its function and for external communication.

Since when using micro solar inverters a number of inverters 131 ... 134 there is the number of PV panels 121 ... 124 corresponds to, it is time-consuming to install every single inverter 131 ... 134 manually using the tablet PC 22nd to configure. Therefore the commissioning of one and all other inverters 131 ... 134 of the photovoltaic system 10 according to 3 performed.

This creates a direct data connection between the inverter 132 of the second PV panel 122 and the inverter of another PV panel, here the inverter as an example 131 of the first PV panel 121 built up. This direct data connection can also already exist in the form of the meshed network between the inverters 131 ... 134 .

A transmission now takes place via this data connection 24 the configuration data from the inverter 132 to the inverter 131 instead of. The configuration data are saved there again in a memory area provided for this purpose. The inverter 131 thus receives the necessary data for its function and for external communication, but this time not through manual intervention using the tablet PC 22nd , but without manual intervention, i.e. automatically.

It is advantageous if an inverter 131 ... 134 Configuration data is only saved when the memory area provided for it is empty, i.e. no configuration data has yet been saved. This prevents overwriting with incorrect data. For example an inverter 131 ... 134 be configured on delivery, i.e. in the factory state, so that the memory area can be written to. A single writing then changes the state so that further writing is no longer permitted, for example by setting a software flag.

It is then also possible that the inverter 131 ... 134 Another writing, i.e. overwriting of the configuration data by manual intervention using the tablet PC 22nd allow. This means that, for example, a new network password can be recorded without any loss of security.

Sending the configuration data from one of the inverters 131 ... 134 can also be done manually from the tablet PC 22nd made possible. Sending can be stopped manually or automatically when all PV panels are present 121 ... 124 configured. The inverters 131 ... 134 for example, a response to the tablet PC 22nd indicate, either directly or through the meshed network, that they are configured. The user or the software on the tablet PC 22nd knows how many inverters 131 ... 134 exist and can therefore decide when the configuration is complete. As a result, the further sending of the configuration data can then be prevented, for example by setting a software flag, in order to avoid security problems.

List of reference symbols

10

Photovoltaic system

121 ... 124

PV panels

131 ... 134

Inverter

15th

Network router

17th

Internet

22nd

Tablet pc

24

Transmission of the configuration data

Claims (9)

Inverters (131 ... 134), in particular micro solar inverters, designed for attachment to a photovoltaic panel (121..124) and for converting the direct current generated by this photovoltaic panel (121 ... 124) into one Alternating current, with a device for wireless communication, the device for wireless communication being designed to establish a direct data connection to a further inverter and to send data directly to the further inverter and to receive data directly from the further inverter. Inverter (131 ... 134) Claim 1 , in which the device for wireless communication is designed to establish a WLAN connection to the further inverter as a direct data connection. Inverter (131 ... 134) Claim 1 , in which the device for wireless communication is designed to form a meshed wireless network with the further inverter. Inverter (131 ... 134) Claim 1 , in which the device for wireless communication is designed to receive data from the further inverter to a network router (15) from the further inverter and to forward them to the network router (15) and data from the network Router (15) are directed to the other inverter, to be received by the network router (15) and forwarded to the other inverter. Inverter (131 ... 134) Claim 1 , in which the device for wireless communication is designed to send stored data to the further inverter upon receipt of an inquiry message from the further inverter. Inverter (131 ... 134) Claim 1 , in which the device for wireless communication is designed to send network access data as stored data. Inverter (131 ... 134) Claim 1 , in which the device for wireless communication is designed to send configuration data (24) for the electrical configuration for the inverter as stored data. Inverter (131 ... 134) Claim 1 , in which the device for wireless communication is designed to receive network access data and / or configuration data (24) for the electrical configuration for the inverter from the further inverter and to store and use them for your own configuration. Inverter (131 ... 134) Claim 1 configured to define a commissioning period, the device for wireless communication being configured not to send the stored data outside the commissioning period upon receipt of the request message.

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