DE102012011708A1 - Inverter device connected with renewable energy sources e.g. photovoltaic systems, has control unit that switches inverter unit into voltage led mode to connect emergency power supply connected over secondary switch unit with consumers - Google Patents

Abstract

The device (1) has an inverter unit (8) that is provided with a control unit (12) connected to a power meter (17) for measuring in a public power network (3). A security circuit (34) is provided with a primary switch unit (30) and a secondary switch unit (31). The control unit is configured to switch the primary and secondary switch units in case of failure of public power network into a separating state, and to switch the inverter unit into a voltage led mode to connect the emergency power supply connected over the secondary switch unit with consumers (5).

Description

FIELD OF THE INVENTION

The invention relates to an inverter device having at least one inverter unit which can be connected via a first connection device with at least one regenerative energy source, in particular a photovoltaic system, via a second connection device with an accumulator device, and via a connection device with a wiring harness between a public power grid and Consumers can be connected, according to the closer defined in the preamble of claim 1. Art.

STATE OF THE ART

In practice, inverters of all kinds are known in connection with the use of regenerative energy sources, such as photovoltaic systems or small wind turbines, both in the commercial sector and in the home. The photovoltaic electrical energy produced, for example, by solar cells is supplied to the inverter, which converts the supplied DC voltage into a regulated standardized mains voltage. The fluctuations occurring in the regenerative production of electricity with sun and / or wind fluctuations and consumption fluctuations and the need for an emergency power owners of renewable energy recovery increasingly cause the connection of the system with an accumulator device, which especially in the private sector often only in a further expansion stage of the system will be added.

A particular problem is the use of such a system as an emergency power supply in case of failure of the public network, as this special security and connection conditions must be considered.

For safety reasons, it is necessary that in case of failure of the public network, a self-energy supply system to avoid an infeed safely separated from the public grid, which this is usually completely shut down and can not be used for emergency power supply to consumers of the home network.

So-called stand-alone inverters are known from practice, which supply an predominantly separate sub-network in the house via an external switching device.

Such a plant is for example in the EP 1 965 483 A1 which proposes an additional device which is implemented between a public power grid and a self-generating installation. The self-generating system supplies here on the one hand a by means of an independent release point with at least a first switch in parallel to the public power grid switchable AC voltage for feeding into the public power grid, with an additional device located in the network monitoring device for opening the automatic disconnection point in case of power failure of the public power grid, and on the other hand, can be connected directly via a second switching element with one or more connectable to the auxiliary device electrical consumers, wherein a switch connects the node at which the island inverter with its memory, the consumer and the switching element is connected to the public power grid.

The main disadvantages of such a solution, which basically requires two inverters, exist in addition to the high and costly equipment expense in the separation of the house network and the associated electrical installation, which is very complex and solves only a partial problem.

DISCLOSURE OF THE INVENTION

TECHNICAL TASK

It is an object of the present invention to provide an inverter device of the type mentioned above, with which a multi-phase power system of a building unit after a failure of the public network is safely separated from this and the power system of the building unit is powered by the accumulator device with no changes or separate supplies to the supplied consumers or modifications to a service connection box are necessary.

TECHNICAL SOLUTION

This object is achieved with an inverter device according to the features of the preamble of claim 1 such that the single- or multi-phase inverter unit is associated with a safety circuit comprising a first switch means between the connection means, which the inverter unit with the guided between the public power grid and the consumers Wiring harness linked, and the public power grid and a second switch means between the inverter unit and the inverter unit with the wiring harness link connecting means, wherein the control unit in case of failure or malfunction of the public power network associated measurements of the power meter, the first switch means and the Switching the second switch means in a disconnecting state and then connects the connected in a voltage-controlled mode inverter unit via the second switch means with the consumers to the emergency power supply.

BENEFICIAL EFFECTS AND VERSIONS

The invention has the advantage that only a single inverter is required, which makes the safe purely electrical separation of two voltage networks (inverter and power grid) itself, so that in no case a short circuit of these sources of voltage and thus an end user can be harmed.

The invention offers the particular advantage that a home network between house connection and consumers by introducing the components measurement and separation from the grid, separation to the inverter unit and by a safety circuit with low cost emergency power is.

The task of switching between normal and emergency operation can be particularly easily solved with the invention that z. B. in a control box as part or non-component of a home power station or an inverter unit is a safe separation, the entire home network can be passed through the power plant or the control box and so easily integrated into the function emergency power, d. H. retrofitted, or integrated.

In particular, when integrating all or the essential components of the inverter device according to the invention in a common housing, d. H. in the arrangement of the at least one inverter unit associated with a regenerative energy source, the connecting device with the wiring harness between the public power grid and consumers, the control unit, the safety circuit with the first and second switching device, possibly the power meter and, if applicable, the accumulator device in a common control cabinet or Control box, can be created by introducing a few more components and by software of the inverter, a complete emergency power device that makes the home network self-sufficient without any additional equipment and external cables and is protected from dirt and unauthorized access.

Since only a few switching and disconnecting elements as well as the software of the inverter, a previously current-controlled solution can be converted into a voltage-controlled solution for emergency power, switching between normal operation and emergency operation takes place exclusively within the device.

The switch devices of the safety circuit of the inverter unit can represent structurally separate components, so that a simple retrofit can be realized.

The at least one inverter unit can be designed as a solar inverter, which perceives the emergency power function by optional voltage, wherein preferably a DC link of the inverter unit is maintained by the connected to a battery inverter unit accumulator.

Furthermore, the at least one inverter unit may be an integrally formed solar and battery inverter, d. H. a so-called DC connection of the accumulator to the inverter.

In an advantageous embodiment, the control unit adjusts the disconnecting state of the first and second switch devices in the event of a failure or malfunction of the public power grid by a purely electrical status evaluation, in particular by means of auxiliary contacts.

By such an evaluation, if necessary together with an electronic safety control unit, a faulty circuit can be safely avoided.

In any case, ensuring the network separation by reading the first switch unit is such that the state of the separation is carried out electrically and thus independent of software.

The switch units of the safety circuit can comprise circuit breakers and / or relays and thus be designed in conformity with the standard.

The electrical sequence of the separation and reconnection of the at least one inverter unit can be controlled by means of an interface between the inverter unit associated with the regenerative energy source and the battery inverter unit, wherein from the control unit to the interface an emergency power operation associated signal can be output and the inverter unit from the interface in a Emergency power mode is switchable. That is, the switchover to emergency operation and back to normal operation, the inverter executes command of the interface, which can also be implemented internally. For this purpose, the interface may expediently have a network measuring device.

The electrical sequence of the separation and reconnection of the at least one inverter unit can also be via an internal design be implemented in the interface, so that the inverter can safely switch to voltage mode without its own network measurement, as this ensure the external units or as internally designed units for measurement and separation.

Advantageously, a reconnection condition for the inverter unit after a power disconnection of the inverter unit by means of the first and second switch means when a purely electrically disconnected state of the safety circuit is detected, for example by reading the state of the first switch means with the result that the state of the separation is carried out electrically and thus independent of software.

A particularly safe state is further achieved if the at least one inverter unit can be switched to emergency power operation by means of the interface formed with a control function and an intermediate circuit purely electrically without its own measurements of the inverter unit.

Further advantages and advantageous developments of the invention will become apparent from the claims and the embodiment described in principle with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWING

Embodiments of an emergency current-capable power supply system of a house, which is connected to a photovoltaic system and a public power grid are in 1 and 2 the drawing simplified illustrated as a schematic diagram and are explained in more detail below.

EMBODIMENTS OF THE INVENTION

Referring to the figures of the drawing, a system for supplying a house with electrical energy is shown in each case, wherein an inverter device 1 a trained as a solar inverter inverter unit 8th which has a first connection device 6 with a trained as a photovoltaic plant regenerative energy source 7 and via a second connection device with an accumulator device 9 and their associated battery inverter unit 10 connected is.

The solar inverter unit 8th and the battery inverter unit 10 are at the in 1 shown execution as a combined solar / battery inverter, while the inverter units in the execution of 2 represent separate components.

The solar inverter 8th is via a connection point forming an entry point 36 with a wiring harness 18 connectable, which between a network connection unit 2 to an external, public energy network 3 and a connection device 4 with consumers 5 a three-phase house network is performed.

The solar / battery inverter 8th . 10 is together with a switching device 11 and a control unit having a computer unit 12 , which is designed to perform an electronic power management, integral in a cabinet-like housing 13 arranged. Installation space technology is the housing 13 modular structure with an accommodation space for the accumulator device 9 , which in the embodiment shown with modular recording spaces for the contact-protected recording of replaceable batteries 14A . 14B . 14C is formed, an adjacent, above or below arranged receiving space for the combined solar / battery inverter units 8th . 10 , a receiving space for the integral in the housing 13 trained switching device 11 , a recording room for the control unit 12 with a display device designed, for example, as a touch display 15 , through which all essential functions can be easily controlled and all information about solar power, battery state of charge and power supply or reference can be read, a recording room for a measuring device 16 for measuring the public network 3 supplied electrical power and a receiving space for another designed as a power meter measuring device 17 to measure the on the public energy grid 3 applied voltage.

Installation space technology can with the control unit 12 cooperating power meter 17 again with the measuring device 16 to a component as a measuring module 20 be summarized.

The housing 13 is formed with integrated signal and power lines, the individual components depending on the design, if necessary, via connectors hereby or via plug-in connections with each other wirelessly in the housing 13 can be arranged.

About the power train 18 receiving cable is the housing 13 with a so-called house connection box 19 connected, which the network connection unit 2 to the external energy network 3 and the connection unit 4 for the three-phase home network with consumers 5 forms. Inside the service connection box 19 branches from three-phase connections to the external power network 3 and the home network between a provider usually provided, but technically not required reference / feed meter 21 and a fuse unit 22 a three-phase in the wiring harness 18 formed conductor loop 23 to the housing 13 from. In the case 13 is the wiring harness 18 with the measuring module 20 for three-phase current measurement and voltage monitoring of the public network 3 connected and electrically conductive with the inverter units 8th . 10 the photovoltaic system 7 and the accumulator device 9 interconnected.

The housing 13 with the components of the solar and battery inverter units arranged therein 8th . 10 , the accumulator device 9 , the switching device 11 whose rear wall, for example, at the same time the front of the combined solar and battery inverter units 8th . 10 can form, and the control unit 12 forms a compact, visually uniform and, for example, coverable by a door device that can be installed in a private home or a small business with little space requirements. Installation technology, the system shown is a "mount &use" solution, ie it can be set up and put into operation without major installation effort, with no changes must be made to the consumers themselves or to sockets of consumers.

To go about the inverter unit 8th and the connected photovoltaic system 7 and accumulator device 9 an emergency power supply to the consumer 5 in case of failure of the public network 3 to enable is the inverter unit 8th a security circuit 34 assigned, which carries out a secure line disconnection in the event of a power failure and which represents an error protection by electronic evaluation.

This includes the safety circuit 34 two switch devices 30 . 31 , of which a first switching device 30 for grid separation of the inverter unit 8th and thus serves the home power station and between the inverter unit 8th with the wiring harness 18 linking connection device 36 and the public power grid 3 is arranged. A second switch device 31 serves to separate the home power station or the inverter unit 8th to the home network and its consumers 5 towards and between the inverter unit 8th and the inverter unit 8th with the wiring harness 18 linking connection device 36 arranged.

The switch devices 30 . 31 the safety circuit 34 present case of the inverter unit 8th separate components, but which in the common housing 13 are arranged.

Both switch units 30 and 31 are over the security circuit 34 protected in their switching behavior and can be used as part of the control unit 12 or by connecting to the control unit 12 switch between an emergency operation and a normal operation. The change can be uninterrupted or intermittent.

Will be a failure or disruption of the public power network 3 based on this state associated measurement results of the power meter 17 detected, the control unit turns off 12 both switch devices 30 . 31 , which are designed as safe disconnection points, for example by means of circuit breaker or disconnect relays, in a disconnecting state. Subsequently, the inverter unit switched to a voltage-driven mode 8th via the second switch device 31 with the consumers 5 connected to their emergency power supply.

The switching between emergency power operation and normal operation is thus carried out via the measurement of the entire network performance and the state of the network via the power meter 17 and a circuit of the safety circuit 34 that the two separation points 30 . 31 switches and monitors safely. This circuit works purely electrically without software.

About one with the power meter 17 and the security circuit 34 cooperating electronic safety control unit 35 the control unit 12 the system is controlled by software superordinate, wherein the Saftey control unit to perform the electrical process of disconnection and reconnection of the inverter unit 8th Signals to an inverter unit 8th the regenerative energy source 7 controlling interface 38 between the inverter unit 8th and the battery inverter unit 10 outputs, if a safe, pure electrical isolation at the switch devices 30 . 31 and thus a reconnection condition for the inverter unit 8th is recognized.

Once at the interface 38 , which in the combined solar energy inverter 8th . 10 according to the execution 1 is executed internally, an emergency power operation assigned signal received, this switches the inverter unit 8th in a voltage-generating emergency power mode.

The inverter unit 8th is thus about the trained with a control function and a DC link interface 38 purely electrical without own measurements of the inverter unit 8th switched to emergency operation.

Conversely, when resuming a normal operating voltage of the public network 3 and their detection via the power meter 17 automatically via the control unit 12 and the security circuit 34 a closure of the switch devices 30 . 31 and a changeover of the inverter unit 8th in normal operating mode with a possible mains supply.

In other embodiments, of course, a wide variety of arrangements and expansion stages of the system shown are conceivable, wherein the control device 12 z. B. can not only be connected to an external computer to retrieve all data and update software and applications, but can also be controlled remotely via a smartphone, and remote-operated circuit breakers can be used.

It is understood that the person skilled in the art also the point of interconnection of one or more inverter units with the wiring harness 18 depending on the given requirements. A common feed to a point on the consumer side of the power meter 17 has the advantage that a measuring device arranged in the wiring harness exactly matches the network connection unit 2 can detect applied electrical power or voltage, resulting in an additional computational determination taking into account of the feed-in measuring device 16 recorded power is unnecessary. The feed-in measuring device 16 can be completely eliminated, although it is advantageous for Eigenstromeinspeisungsmessung.

In an expansion stage, for example, a further power generating device with an associated inverter unit can be connected to the wiring harness, wherein the type of power generating device is irrelevant. It may be another photovoltaic system, a wind turbine, a combined heat and power plant, a fuel cell or even a generator. Also, several additional inverter units and power generation devices can be switched on.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1965483 A1 [0006]

Claims (11)

Inverter device with at least one inverter unit ( 8th ), which with at least one regenerative energy source ( 7 ), in particular a photovoltaic system, with an accumulator device ( 9 ) and via a connection device ( 36 ) with a wiring harness ( 18 ) between a public energy network ( 3 ) and consumers ( 5 ) is connectable, wherein the inverter unit ( 8th ) a control unit ( 12 ) associated with a power meter ( 17 ) on the measurement of the public energy network ( 3 ) voltage, characterized in that the inverter unit ( 8th ) a security circuit ( 34 ), comprising a first switch device ( 30 ) between the inverter unit ( 8th ) with the wiring harness ( 18 ) linking device ( 36 ) and the public energy network ( 3 ) and a second switch device ( 31 ) between the inverter unit ( 8th ) and the inverter unit ( 8th ) with the wiring harness ( 18 ) between the public energy network ( 3 ) and consumers ( 5 ) linking device ( 36 ), the control unit ( 12 ) in the event of a failure or disruption of the public energy network ( 3 ) associated measurement results of the power meter ( 17 ) the first switching device ( 30 ) and the second switch device ( 31 ) switches to a disconnecting state and then the switched into a voltage-controlled mode inverter unit ( 8th ) via the second switch device ( 31 ) with consumers ( 5 ) connects to their emergency power supply. An inverter device according to claim 1, characterized in that the switch devices ( 30 . 31 ) of the safety circuit ( 34 ) from the inverter unit ( 8th ) represent separate building components. Inverter device according to claim 1 or 2, characterized in that the at least one inverter unit ( 8th ) is designed as a solar inverter, the emergency power function perceives by optional voltage control, preferably a DC link of the inverter unit ( 8th ) of the with a battery inverter unit ( 10 ) connected accumulator device ( 9 ) is maintained. Inverter device according to one of Claims 1 to 3, characterized in that the at least one inverter unit is an integrally formed solar and battery inverter ( 8th . 10 ). Inverter device according to one of claims 1 to 4, characterized in that the at least one of a regenerative energy source ( 7 ) associated inverter unit ( 8th ), the connection device ( 36 ) with the wiring harness ( 18 ) between the public energy network ( 3 ) and consumers ( 5 ), the control unit ( 12 ), the safety circuit ( 34 ) with the first ( 30 ) and second ( 31 ) Switch device, possibly the power meter ( 17 ) and possibly the accumulator device ( 9 . 10 ) in a common housing ( 13 ) are arranged. Inverter device according to one of Claims 1 to 5, characterized in that the control unit ( 12 ) the separating state of the first ( 30 ) and second ( 31 ) Switch equipment in the event of a failure or malfunction of the public power grid ( 3 ) by a purely electrical condition evaluation, in particular by means of auxiliary contacts adjusts. Inverter device according to one of Claims 1 to 6, characterized in that the switch units ( 30 . 31 ) of the safety circuit ( 34 ) Comprise circuit breakers and / or relays. Inverter device according to one of claims 1 to 7, characterized in that the electrical sequence of the separation and reconnection of the at least one inverter unit ( 8th ) by means of an interface ( 38 ) between the regenerative energy source ( 7 ) associated inverter unit ( 8th ) and the battery inverter unit ( 10 ) is controlled by the control unit ( 12 ) to the interface ( 38 ) a signal assigned to an emergency power operation can be output and the inverter unit ( 8th ) from the interface ( 38 ) is switchable into an emergency power mode. Inverter device according to claim 8, characterized in that the interface ( 38 ) has a network measuring device. Inverter device according to one of Claims 1 to 9, characterized in that the control unit ( 12 ) after a disconnection of the inverter unit ( 8th ) by means of the first ( 30 ) and second ( 31 ) Switch means a reclosing condition for the inverter unit ( 8th ) detects when the safety circuit ( 34 ) sets purely electrically a separating state. Inverter device according to one of claims 8 to 10, characterized in that the at least one inverter unit ( 8th ) by the interface (with a control function and an intermediate circuit) ( 38 ) purely electrically without own measurements of the inverter unit ( 8th ) is switchable to emergency power operation.

Images