EP1657797B1 - Protection device for apparatus carrying load current - Google Patents

Abstract

The protective cover (5) has electrical contacts (10) in electrical connection with the additional contacts (11) of the inverter (1). When the protective cover is removed, the contacts of the protective cover are separated from the additional contacts, thereby reducing the load current.

Description

The invention relates to a protective device for a load current-carrying device for preventing or reducing an arc during a separation process from the load current-carrying plug contacts using a switch that reduces the load current so far that a harmless load current remains with a device attachable protective cover for the load current plug contacts, the pulling the load current plug contacts difficult as long as it is attached to the device, wherein the protective cover has a means which is so in operative connection with the switch that the load current is reduced by the switch when the protective cover is removed from the device.

In the DE 102 25 259 B3 a protection device is described in which an arc protection is realized by a clocked semiconductor device is used. This is connected in series with an auxiliary contact. The auxiliary contact is designed as a trailing contact, so that it is disconnected after the load current contact. As a result, the load current has been reduced so far, when the load current contacts are separated, that no arc is formed.

Inverters with an integrated DC load disconnector are known. However, it may be forgotten to operate this before the load plugs are removed. This can cause an arc, which can lead to personal injury.

From the DE 94 09 534 U1 a device for the grid connection of a solar generator is known, wherein a module distributor and a network coupling device are provided. In this case, the module distributor inputs for solar modules and an output for a network coupling device, wherein the network coupling device is connected to one or more inverters, and moreover has an output for a phase of the AC network. The inverter has a cover which mechanically disconnects the inverter when it is lifted.

From the US 6,375,619 B1 is known with respect to an ultrasound examination device that on the connector associated mechanical locking electrical contact is provided.

Both from the DE 198 82 471 T5 as well as from the US 5,542,425 A a protective device of the type mentioned is known. In this case, the opening is detected by a detection switch when opening the protective cover, wherein when the detection switch responds when charging a battery or the power supply by the battery, an internal switching circuit of the power control unit is opened.

Out US 2,439,708 a pivotable socket cover is known, which engages the plugged power plug in the closed state. In this condition, the power plugs can not be removed from the sockets. At the same time an electrical connection to the network is made via actuation pins on the cover inside the sockets only when the cover is closed. The actuation pins provide only the power to push two contacts against each other, which are located within the sockets. The actuation pins therefore carry no power.

The under the number EP 0,437,696 A1 Published European patent application shows a wall cover of a remotely controllable socket containing electrically conductive contacts. These transmit signals from an interface located adjacent to the socket to the control unit of the remotely controllable socket. There is no significant power transfer through these contacts.

The invention has for its object to provide a protective device of the generic type, which protects against arcs in a simple manner.

This object is achieved by the characterizing features of claim 1 in conjunction with its features of the preamble, wherein the switch may be formed as a semiconductor switch, clocked semiconductor switch, as a relay or as a so-called one-time switch. A one-time switch is understood to be a switch which can not be closed after a single actuation; he acts as a kind of security.

The protective cover according to the invention prevents on the one hand, that the load current contacts are pulled, as long as it is mounted on the device. On the other hand, the protective cover is removable. By removing the protective cover acts the inventive means in which the clocked semiconductor device is used. This reduces the load current so far that when removing the load current contacts no or at least only a harmless arc for people can arise.

The protective cover according to the invention allows additional load disconnectors in the device to be dispensed with, since disconnection at high load current is not possible without the invention. In this way, the relevant standards and regulations are complied with.

The control means may be a mechanical or electromechanical means. For example, an actuating pin or the like may be provided on the protective cover which operates a switch provided on the device when the protective cover is mounted. The switch contacts of the switch are parallel to the clocked semiconductor switch. This in turn lies in the load circuit, in particular in the DC circuit. For example, with the protective cover mounted, the switch is closed so that the load current flows through the switch. With the protective cover removed, the contact is opened so that the load current through the clocked Semiconductor switch flows. Since this current is now less or is clocked, an arc protection is given.

Preferably, however, an electrical solution is used in which the protective cover has electrical contacts for electrical connection with additional contacts on the device, so that when removing the protective cover, the contacts of the protective cover separated from the additional contacts and the load current is reduced. This solution provides, in particular, that the protective cover comprises a short-circuiting bridge as a means which short-circuits the additional contacts when the protective cover is mounted over the contacts of the protective cover.

The short circuit bridge integrated in the protective cover creates a very simple control of the load current. When the cover is mounted, the shorting bridge will engage and the load current may be high. If the short-circuit bridge or the cover is removed, a lesser current sets in through the clocked semiconductor component, which interrupts the current continuously at regular or even irregular intervals.

According to an advantageous embodiment of the invention, it is provided that the short-circuiting bridge is connected in parallel with the semiconductor component and the semiconductor component with the short-circuiting bridge lies in the load circuit. In this configuration, a closed switch would bypass the semiconductor device. The current goes the path of least resistance. When the protective cover is mounted, the load current flows through the low-resistance bridge. If this is missing because the cover has been removed, the current must flow over the clocked semiconductor switch. As a result, however, the load current is reduced to a safe level.

Advantageously, the semiconductor device can be clocked continuously, which is easy to implement. Since the load current flows through the low - impedance current bridge when the protective cover is mounted, the Semiconductor device no switching losses, resulting in a high efficiency.

A simple extension of existing inverter circuits with the inventive solution is given if the device comprises an inverter module and the semiconductor device is housed in a clock module which is electrically connected to the inverter module.

Further developments of the invention are mentioned in the subclaims.

The invention and further advantages thereof will now be explained in more detail with reference to the drawings.

Fig. 1

eine schematische Darstellung eines Wechselrichters mit einer erfindungsgemäßen Schutzvorrichtung,

Fig. 2

ein Blockschaltbild einer Schaltung der Schutzvorrichtung,

Fig. 3

eine perspektivische Darstellung der Schutzvorrichtung,

Fig. 4

ein Schaltbild der Schaltungsanordnung der Schutzvorrichtung,

Fig. 5

ein vereinfachtes Schaltbild bei einer montierten Schutzabdeckung und

Fig. 6

ein vereinfachtes Schaltbild bei entfernter Schutzabdeckung.

It shows:

Fig. 1

a schematic representation of an inverter with a protective device according to the invention,

Fig. 2

a block diagram of a circuit of the protection device,

Fig. 3

a perspective view of the protection device,

Fig. 4

a circuit diagram of the circuit arrangement of the protective device,

Fig. 5

a simplified circuit diagram with a mounted protective cover and

Fig. 6

a simplified circuit diagram with the protective cover removed.

Fig. 1 shows a preferred embodiment of the protective device according to the invention for a photovoltaic inverter. 1

The inverter 1 is provided with plug contacts 2, which lead a load current for an input side DC voltage circuit. On the plug contacts 2 PV plug 4 (photovoltaic plug) can be connected, which are connected to photovoltaic modules 3 (solar generators), such as Fig. 2 illustrated. The protective device is preferably located on a DC circuit, in particular on an input-side circuit (DC circuit).

Before the PV plugs or the plug contacts 2, a protective cover 5 can be mounted, as the FIGS. 1 and 3 illustrate. The protective cover 5 can be positively and / or non-positively attached to a housing of the inverter 1. When mounted, the cover prevents the PV plugs 4 from being pulled out and breaking the load circuit at high current. An interruption of the load circuit during a high load current would cause an arc.

To reduce this high load current, a module 6 is connected in series with a clocked semiconductor switch 7 to an inverter circuit or an inverter module 8, such as Fig. 2 shows. In order to bridge the semiconductor switch 7 during operation or when the protective cover 5 is mounted, it is preferable to use a current bridge or short-circuiting bridge 9, which is integrated in the protective cover 5. The shorting bridge 9 is automatically connected to existing on the protective cover 5 contacts 10 and additional contacts 11 on the housing of the inverter 1 when the protective cover 5 is mounted. The load current can thus flow with little loss via the shorting bridge 9 during operation. The short-circuiting bridge 9 is connected practically parallel to the semiconductor switch 7.

When removing the protective cover 5 of the clocked semiconductor switch 7 and the clock module 6 is in series with the inverter circuit or the inverter module 8. When the protective cover 5 is removed for unplugging the PV plug 4, then the power must therefore necessarily on the clocked semiconductor switch 7 flow, so that a harmless load current remains and no or at least a harmless arc remains when the PV plugs 4 are pulled out.

According to the invention a device attachable protective cover 5 for the load current plug contacts 4 is present, which prevents removal of the load current plug contacts 4, as long as it is attached to the device, the protective cover 5 has an electrical and / or mechanical means (shorting bridge), which is in operative connection with the semiconductor device or the semiconductor switch 7, that the load current is reduced by the semiconductor switch 7, when the protective cover 5 is removed from the device.

The integrated in the protective cover 5 means or control means controls in the broadest sense in a simple manner the load current.

Fig. 4 shows a further circuit diagram showing the arrangement of the shorting bridge 9 and the semiconductor switch 7. Here it is easy to see that the short-circuiting bridge 9 preferably short-circuits additional contacts 11 or lies parallel to the semiconductor switch 7. The additional contacts 11 are attached to the device. The semiconductor switch 7 is driven by a clock controller 12, so that the semiconductor device is continuously clocked. Here, the timing is set so that no dangerous arc is formed at the additional contacts 11 when the protective cover 5 is removed.

The FIGS. 5 and 6 show the principle of the current reduction according to the invention. The semiconductor switch 7 is shown in simplified form as a switch. Parallel to this is the shorting bridge 9, which is also shown in simplified form as a switch.

When mounted protective cover 5, the switch 9 is closed. The load current I _L flows through the switch 9, as Fig. 5 shows. If the Protective cover 5 is removed, then a reduced current I _{R flows} through the switch 7, such as Fig. 6 shows.

Instead of an electrical solution with a shorting bridge, therefore, a mechanical or electromechanical solution is conceivable. The switch 9 could be integrated in the device and formed on the protective cover 5 mechanically actuated. For operation, an actuating pin or the like which would be attached to the protective cover 5, could serve.

As well as in the FIGS. 1 and 3 is shown, the protective cover 5 on a handle 13, which is preferably formed as a wall. As in Fig. 3 can be seen, the protective cover 5 covers both the additional contacts 11 and the load current or PV contacts. The protective cover 5 is preferably made of plastic, for example a thermoset or thermoplastic. It has, for example, a three-dimensional shape and preferably carries end walls 14, such as Fig. 3 shows. A central web 15 stiffens the cover or serving as a handle 13 wall.

Preferably, a separate contact 2a, 2b is used for each independent input of the inverter. Preferably, four or more contacts 2 are present. Therefore, several additional contact pairs are used, in particular two pairs, such as Fig. 3 shows.

The protective cover 5 is so inventively arranged on the inverter that in the mounted or mated state, the plug-in connections of the inverter are hidden and can not be operated. By removing the protective cover 5 by the integrated electrical contacts a function is triggered, which ensures that a maximum of a harmless for the removal of the connection plug of the inverter current flows through the plug-in connections. By removing the protective cover 5 continues to access the plug-in connections (Contacts 2) released, so that at the latest by the then following removal of the plug-in connections from the inverter a complete separation of the upstream energy source (eg PV system) takes place.

The additional control unit for covering the inverter's connectors effectively prevents arcs that can lead to personal injury. In contrast to a built-in inverter electromechanical load disconnector, the load current is not completely switched off, but it remains a pulsed, small current. The constant switching on and off of the semiconductor switch not only reduces the current, but also extinguishes an arc due to the clocking.

It is also possible, instead of the contacts mounted in the protective cover 5, to mount a switch or button in the inverter so that it is actuated by the insertion of the additional part in the inverter.

Instead of a peelable protective cover, a hinge hinged cover can alternatively be used.

LIST OF REFERENCE NUMBERS

1

inverter

2

plug contacts

3

photovoltaic modules

4

PV connector

5

protective cover

6

clock module

7

Semiconductor switches

8th

Inverter module

9

Shorting

10

Contacts (shorting bridge)

11

Additional contacts (device)

12

timing

13

handle

14

end walls

15

gutter

Claims (6)

1. A protective device for a load carrying apparatus for preventing or reducing an electric arc during separation of the load current carrying plug connectors (2) using a clocked semiconductor switch (7) that reduces the load current to such an extent that the load current that remains is harmless,
   characterized by
   a protective cover (5) for the load current plug connectors (2), said cover being implemented as a separate part and securable to the apparatus and preventing the load current plug connectors (2) from being removed as long as it is secured to the apparatus, said protective cover (5) comprising a short-circuit bridge (9) with electric contacts (10) for electrical connection to additional contacts (11) on the apparatus, said short-circuit bridge (9) being connected parallel to said semiconductor switch (7) in the mounted condition, said semiconductor switch (7) then lying in the load current circuit together with said short-circuit bridge (9) so that said semiconductor switch (7) reduces the load current when said protective cover (5) is removed from the apparatus.
2. The protective device as set forth in claim 1,
   characterized in
   that the semiconductor switch (7) is clocked continuously.
3. The protective device as set forth in one or several of the previous claims,
   characterized in
   that the apparatus includes an inverter module (8) and that the switch (7) is accommodated in a clock module (6) that is electrically connected to the inverter module (8).
4. The protective device as set forth in one or several of the previous claims,
   characterized in
   that the apparatus is configured to be a photovoltaic inverter.
5. The protective device as set forth in one or several of the previous claims,
   characterized in
   that the protective cover (5) comprises a grip (13).
6. The protective device as set forth in one or several of the previous claims,
   characterized in
   that the grip (13) in the shape of a wall is formed integral with the protective cover (5).

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