WO2014161828A1

WO2014161828A1 - Inverter and direct-current connection unit for an inverter

Info

Publication number: WO2014161828A1
Application number: PCT/EP2014/056487
Authority: WO
Inventors: Lars Cramer; Jens Dittmar; Lutz HERMANNS; Martin PUTZ; Harald Drangmeister
Original assignee: Sma Solar Technology Ag
Priority date: 2013-04-03
Filing date: 2014-03-31
Publication date: 2014-10-09
Also published as: DE202013012368U1; CN205141304U; DE102013103331A1

Abstract

The invention relates to a direct-current connection unit (20) for an inverter (10), said direct-current connection unit comprising a direct-current disconnecting switch (23) having connection contacts for connecting to direct-current connection lines (25). The direct-current connection unit (20) is characterized in that the connection contacts are touch-proof. The direct-current connection unit also has an electrical plug connector (26), which can be connected to the direct-current connection lines (25) by means of the direct-current disconnecting switch (23). The invention further relates to an inverter (10), in particular for a photovoltaic system, said inverter being characterized in that a free space for accommodating at least one direct-current connection unit (20) having a touch-proof plug connector (26) is formed inside a housing of the inverter (10), a mating plug connector (14) that interacts with the plug connector (26) of the direct-current connection unit (20) being arranged in the inverter (10). The invention further relates to an energy generation system comprising such a direct-current connection unit (20) and such an inverter (10).

Description

Inverter and DC connection unit for an inverter

The invention relates to a DC power supply unit, hereinafter abbreviated DC (Direct Current) -Anschlusseinheit called, for an inverter with at least one DC disconnect switch (DC disconnector) with terminals for connection to DC power cables (DC connecting cables), a corresponding inverter, and a power generation system.

Inverters are for example converted into photovoltaic systems for converting the direct current supplied by a photovoltaic generator into an alternating current suitable for feeding into a power supply network. The photovoltaic generator, abbreviated to PV generator below, typically comprises a plurality of photovoltaic modules (PV modules), which form a so-called string in series. The series connection of the PV modules results in voltages in the range of several 100 V (V) at the output of the PV generator. With such a high voltage, ohmic losses in the DC lines via which the PV generator is connected to a DC input of the inverter are advantageously reduced, whereby cost-effective DC lines with a smaller conductor cross-section can be used. Since the generator side not mandatory protective devices are provided, which allow a voltage isolation of the DC connection lines, the high voltage applied to the DC power lines of the PV generator requires protection measures during the initial installation or replacement of the inverter to an installer against a potentially life-threatening electric shock protect. In order to enable a connection of the PV generator to the inverter without voltage, a DC connection unit is provided near the inverter, which has a DC disconnector, which separates the DC lines coming from the PV generator as far as possible. DC terminal units are known which are positioned as separate units in the vicinity of the inverter. Connection cables between the DC connection unit and the inverter can be de-energized by the DC disconnect switch, so that initial installation or replacement of the inverter can be carried out safely. However, the additional DC connection unit leads to an increased material and installation costs in the installation of the photovoltaic system.

The publication WO 2012/040761 A1 describes a photovoltaic system in which a DC connection unit with integrated DC circuit breaker is provided, which is connected via DC connections, for example screwed or clamped connections, to the DC lines coming from the PV generator is. The DC connection unit also has plug-in contacts, with which it is plugged directly into an inverter of the PV system. In this way, the additional installation effort for a separate DC connection unit is eliminated. However, the DC connections designed as screwed or clamped connections do not provide adequate protection against the possibly life-threatening voltage of the PV generator. It is therefore an object of the present invention to provide a DC connection unit for an inverter and an inverter, with which a very simple and safe installation of an inverter of a PV system is possible. This object is achieved by a DC connection unit for an inverter and an inverter having the features of the respective independent claim. The task is further solved by a system of inverter and DC connection unit. Advantageous embodiments and further developments are the subject of the dependent claims.

A DC connection unit according to the invention of the type mentioned above is characterized in that the connection contacts are formed safe to touch and that the DC connection unit further comprises at least one touch-safe electrical connector, via the DC Disconnector is connected to the finger-safe connection contacts for the DC connection cables.

An inverter can be installed or replaced by disconnecting the DC connector with its connector from the inverter. This is preferably done safely after the connector is disconnected from the DC circuit breaker. The DC connection unit can be arranged within a housing of the inverter, whereby the assembly effort is minimized. Due to the touch-proof design of both the connection contacts and the plug connector, there is no danger from a DC connection unit disconnected from the inverter during installation or maintenance. By way of example, the DC disconnect switch can be arranged within a housing of the DC connection unit such that the connection to the DC connection leads lies intact within the housing. Alternatively, a separate protective cover may be provided for the connection contacts.

An advantageous embodiment of the DC connection unit has a closed housing with a lid and a cable bushing for the DC connection cables, as well as an actuating element for the DC disconnector. Preferably, the DC disconnect switch is a rotary switch, wherein the actuating element, for example formed as an actuating knob, is connected to the DC rotary switch via an axis which has at least one flattened side in a cross section between the DC disconnector and the actuating element in its cross-section. Together with a formed in a housing part of the inverter Schlußiförmigen recess is achieved so that a removal and / or insertion of the DC connection unit is only possible if the DC disconnect switch is in a position in which the plug contact is not energized. Thus, on the one hand prevents possible formation of an arc when staking the DC terminal unit under load and on the other hand reduces the risk that emanates from a high-voltage connector. Under the term cable bushing here are other types of Implementation of electrical connections such as pipe penetrations, so-called conduits, understood.

In a further advantageous embodiment of the DC connection unit, an actuation of the DC disconnect switch is mechanically blocked when the finger-safe connector is not in operative connection with a mating connector. In this way, it is additionally possible to prevent the DC disconnect switch of a withdrawn DC connection unit from being switched on, as a result of which the plug connector would again be subjected to voltage.

An inventive inverter, in particular for a PV system, is characterized in that within a housing of the inverter, a free space for receiving at least one Gleichstromanschus- selement is formed with a touch-safe connector, wherein in the inverter, a mating connector is arranged with the Connector of the DC connection element cooperates. This results in the advantages mentioned in connection with the DC connection element.

In an advantageous embodiment of the inverter, the mating connector is arranged directly on a printed circuit board of the inverter. This allows compact integration of the DC connection unit into the inverter.

In a further advantageous embodiment of the inverter, a securing means is provided which mechanically interacts with the DC connection unit in such a way that removal and / or insertion of the DC connection unit into the inverter is possible only when the DC disconnection unit of the DC connection unit is switched off. Preferably, the securing means comprises a keyhole-shaped recess of a housing chassis, wherein the keyhole-shaped recess for receiving a provided for actuating the DC circuit breaker axis is provided with non-circular cross-section. As in connection with the DC connection unit described, so a removal of the DC connection unit can be prevented under load.

According to a further aspect of the invention, such an inverter and at least one such DC connection element form a power generation system. This in turn results in the advantages mentioned in connection with the DC connection element. In addition to the elements mentioned above, other energy-generating elements such as PV generators, connection and communication technology, may belong to the power generation system.

The invention will be explained in more detail by means of exemplary embodiments with the aid of five figures. Show it:

Figure 1 is a schematic perspective view of an inverter with a DC connection unit;

Figure 2 is a schematic exploded perspective view of the inverter of Figure 1;

FIG. 3 shows a detailed detail of FIG. 2;

Figure 4 is a plan view of the underside of the DC terminal unit of the figure

3 and

FIG. 5 shows a sectional drawing through the DC connection unit along the in

Figure 4 illustrated section line A-A.

Fig. 1 shows in a perspective view as an example of an inverter 10, a photovoltaic inverter. The inverter 10 has a housing chassis 1 1, which carries the essential components of the inverter 10. The housing chassis 1 1 is covered with a lid 16 which has recesses 161 and 162 on one side, which usually points downwards during operation, through which the housing chassis 1 1 is accessible and are guided through the connecting lines in the inverter 10. In the illustrated example, the recess 161 serves to supply AC lines and / or other cables, such as communication lines, not shown here, and the recess 162 to supply DC power from a PV generator via a DC connecting line 25. For this purpose, the inverter is used 10 a DC connection unit 20 is arranged, which has a DC disconnect switch 23 (see Fig. 5), of which the Fig. 1, the operating knob 232 is visible as a control element and a cable bushing 24, through which the two-pole DC connecting line 25 out which is connected at its other end to the PV generator. As an alternative to the illustrated cable duct 24, other types of implementation of electrical connections such as pipe passages, so-called conduits, can be used. FIG. 2 shows the inverter 10 of FIG. 1 in a perspective exploded view. In the housing chassis 1 1 of the inverter 10, a printed circuit board frame 12 is inserted in the illustrated embodiment, which carries a printed circuit board 13. On the printed circuit board 13, among other electronic and electrical components of the inverter 10, not shown here are arranged.

The DC connection unit 20 is placed on the circuit board 13, wherein it contacts printed conductors of the printed circuit board 13 via an electrical plug connection 14. The area of the circuit board 13 and the DC connection unit 20 circled in FIG. 2 is shown in greater detail in FIG. 3. Further details of the DC terminal unit 20 will become apparent from Fig. 4, which shows the DC terminal unit 20 in a plan view from the bottom thereof, and Fig. 5, which shows a cross-sectional view along the section line A-A shown in Fig. 4.

When the DC connection unit 20 is placed on the printed circuit board 13, the DC connection unit 20 makes contact with its plug connector 26 (see Fig. 4) with a mating connector 14 which is arranged on the printed circuit board 13, in particular soldered. The plug connector 26 of the DC connection unit 20 shows speaking plug contacts 261 which are recessed as safe as possible in the DC terminal unit 20. The mating connector 14 of the inverter 10 has corresponding plug contacts 141 which are surrounded by a Isolierschürze 142.

The DC connection unit 20 has a housing 21 with cover 22. The housing 21 and its cover 22 surround all components with possibly exposed electrical connections safe to touch and, if necessary, sufficiently surrounded the requirements of certain insulation classes. On the housing 21 undercut webs 21 1 are formed, which are guided during insertion with DC connection unit 20 in the inverter 10 in corresponding insertion slots 1 1 1, which are positioned appropriately in the housing chassis 1 1 introduced. Other types of fastening such as locking elements or screw for attaching the housing 21 in the inverter 10 are also conceivable.

Between the undercut webs 21 1, the cable bushing 24 and the operating knob 232 are arranged on the outwardly facing side of the DC connection unit 20. The operating knob 232 serves to actuate the DC disconnecting switch 23 arranged inside the DC connecting unit 20 by means of an axis 231 (compare FIGS. 4 and 5). In the housing chassis 1 1 1 1 1 corresponding recesses 1 12, 1 13 are formed between the insertion slots, which receive the cable bushing 24 and the axis 231 when inserted DC connection unit 20.

The recess 1 13 is formed for the axis 231 in the form of a keyhole and the axis 231 in cross-section not round, but flattened on two sides. The non-round configuration of the axis 231 in the region between the operating knob 232 and the housing 21, in which the axis 231 is inserted into the keyhole-shaped recess 1 13, can be clearly seen in the comparison of Figures 4 and 5, in which the operating knob 232 in the blocking position is shown. Through this interaction of the axis 231 and the keyhole-shaped recess 1 13 it is achieved that the DC connection unit 20 only in one position of the DC disconnector 23 in the inverter 10 can be used or removed from the inverter 10, in which the DC disconnect switch 23 is open. Otherwise, the axis cross-section in the removal direction is increased such that the axis 231 does not fit through the narrowed portion of the recess 13 and the removal of the DC connection unit 20 is blocked. Thus, insertion and in particular removal of the DC connection unit 20 under load is prevented, as a result of which arcing is prevented, in particular when the DC connection unit 20 is removed. Of course, can be used for this purpose, other security geometries in the design of recess 1 13 and axis 231, or use other, not formgebundene, security mechanisms.

In addition, it can be provided that an actuation of the DC switch 23 is blocked when the DC connection unit 20 is removed. In this way it is prevented that a removed DC connection unit 20, which is still connected via its connecting cable 25 nor with a voltage-providing PV generator, is acted on the plug contacts 261 of the connector 26 with the voltage of the PV generator. Such an actuation lock of the DC disconnect switch 23 can be achieved, for example, via a mechanical blocking of the DC disconnect switch 23, which is canceled by an inserted counter connector 14.

The DC connection unit 20 which can be removed from the inverter 10 makes it possible to permanently wire a PV generator via the DC connection line 25 to the DC circuit breaker 23 with the cover 22 of the DC connection unit 20 removed. For example, the connection contacts arranged within the DC connection unit 20 on the DC disconnect switch 23 can be designed as screw contacts for this purpose. When installing the inverter 10 or when replacing the inverter 10, the connector 26 is de-energized by appropriate operation of the DC disconnect switch 23, after which the DC connection unit 20 can be safely removed from the inverter 10 or inserted into the inverter 10. After the one-time wiring of the DC connecting cable 25 with the DC Disconnector 23 can be followed by a safe and tool-free installation of the inverter 10.

Instruction list Inverter

Cases chassis

insertion slot

recess

Card cage

circuit board

mating connector

plug contact

insulating skirt

protective cover

cover

Recess DC connection unit

casing

undercut bridge

cover

DC circuit breaker

axis

operating knob

Grommet

DC connection cable

Connectors

plug contact

Claims

claims

1 . DC terminal unit (20) for an inverter (10), comprising a DC disconnect switch (23) with connection contacts for connection to DC connection lines (25), characterized in that the connection contacts are formed safe to touch and that the DC terminal unit (20) further comprises a touch-safe electrical connector (26 ), which is connectable via the DC disconnect switch (23) with the DC connection leads (25).

2. DC power supply unit (20) according to claim 1, comprising a sealed housing (21) with cover (22) with a cable bushing (24) for the DC power cables (25) and an actuator for the DC disconnector (23).

A DC terminal unit (20) according to claim 1 or 2, wherein said DC disconnect switch (23) is a rotary switch, said actuator (232) being connected to said DC disconnect switch (23) via an axis (231) connected in one between said DC disconnect switch (23) and the actuating element has at least one flattened side in its cross section.

The DC power supply unit (20) of any one of claims 1 to 3, wherein actuation of the DC disconnect switch (23) is mechanically blocked when the plug connector (26) is not in operative connection with a mating connector (14).

5. inverter (10), in particular for a photovoltaic system, characterized in that within a housing of the inverter (10) is a free space for receiving at least one DC terminal unit (20) with a connector (26), wherein in the inverter (10) a mating connector (14) is arranged, which cooperates with the connector (26) of the DC connection unit (20).

6. inverter (10) according to claim 5, wherein the mating connector (14) directly on a circuit board (13) of the inverter (10) is arranged.

7. Inverter (10) according to claim 5 or 6, wherein the securing means is provided, which mechanically interacts with the DC power supply unit (20) such that a removal and / or insertion of the DC power supply unit (20) in the inverter (10) only when switched off DC disconnect switch (23) of the DC power supply unit (20) is possible.

8. Inverter (10) according to claim 7, wherein the securing means in a keyhole-shaped recess (1 13) of a housing chassis (1 1), wherein the keyhole-shaped recess (1 13) for receiving an axis for actuating the DC disconnector (23) provided (231) is provided with non-circular cross-section.

9. A power generation system comprising an inverter (10) according to any one of claims 5 to 8, in which at least one removable DC power supply unit (20) is used according to one of claims 1 to 4.