DE102015008305A1 - Energy management system for a power generation system - Google Patents

Abstract

The invention relates to a DC coupled energy management system (10) for a power generation plant (100), in particular a photovoltaic system comprising a control unit (30), a sensor unit (32) for measuring an electrical balance between consumers (80) of the power plant (100) and a grid connection (20) a power supply network (200), and a DC / DC converter (22) connected to a first connection (24) to an electrical connection line (16) of the power generation plant (100) between an energy converter (12) and a power supply coupled inverter (14) and with a second connection (26) to at least one energy storage unit (40) is connected. The control unit (30) is designed for communication with the sensor unit (32), the energy storage unit (40) and the DC / DC converter (22). The energy converter (12) is provided to provide a variable DC power depending on operating and / or environmental conditions. Furthermore, removal or supply of electrical energy by the DC / DC converter (22) is controllable by means of the control unit (30), wherein the control unit (30) controls the DC / DC converter (22) in accordance with that of the sensor unit (32). certain electrical balance controls. The invention further relates to a power generation plant (100) having such a DC coupled energy management system (10), a DC / DC converter for such a DC coupled energy management system (10), and a method of operating such a power plant (100) with such a DC coupled energy management system (100). 10).

Description

Technical area

The invention relates to a DC-coupled energy management system for a power generation plant, in particular a photovoltaic system, a power generation plant with a DC coupled energy management system, a DC / DC converter for a DC coupled energy management system, and a method of operating a power plant with a DC coupled energy management system.

State of the art

It is known to electrically connect photovoltaic modules (PV modules) of a PV system by means of a series and / or parallel connection to so-called strings of a PV unit. Depending on the size of the PV unit and the PV modules used, the voltage level of these strings ranges from 30 to 1500 V. The typical current in such an electrical connection line is in the range of 0.1 to 30 A. DC cable connected to a string input of a grid connected inverter. The grid-connected inverter may optionally have several such string inputs, to each of which a string can be connected.

From the DE 10 2012 022 729 A1 a designed as a photovoltaic power generation device with a converter device with DC / DC converter is known, wherein the converter means is connected via a first bidirectional DC connection to a battery for discharging and charging the battery and a second DC connection to a supply network coupled inverter. The converter device has a third DC connection, with which it is connected directly to the photovoltaic system.

The second and third DC connection can be bridged via internal or external switches in such a way that the power of the energy generation device can be fed directly into the supply network-coupled inverter. Furthermore, a switch is arranged between the DC / DC converter and the second DC connection and the third DC connection in order to decouple the DC / DC converter from the second DC connection and the third DC connection, if e.g. , B. the solar module in the dark state or at night no external voltage tolerates.

Disclosure of the invention

An object of the invention is therefore to provide a DC coupled power management system which can be easily coupled to a power plant and efficiently operated.

Other objects of the invention are to design a power plant to be efficiently operated with a DC coupled power management system, to provide a DC / DC converter for such a DC coupled power management system, and to provide a method of operating such a power plant efficient operation possible.

The objects are achieved by the features of the independent claims. Favorable embodiments and advantages of the invention will become apparent from the other claims, the description and the drawings.

The invention is based on a DC-coupled energy management system for a power generation plant, in particular a photovoltaic system comprising a control unit, a sensor unit for measuring an electrical balance between consumers of the power generation plant and a grid connection of a power supply network, and a DC / DC converter having a first terminal is connected to an electrical connection line of the power generation plant between an energy converter and a supply network coupled inverter and with a second connection to at least one energy storage unit.

The control unit is in communication with the sensor unit, the energy storage unit and the DC / DC converter. The energy converter is provided for providing a variable DC power depending on operating and / or environmental conditions. The grid-connected inverter is designed to power one or more loads and connected to the grid connection. Further, the DC / DC converter is bidirectional, so that electrical energy can be removed from the electrical connection line and / or electrical energy can be supplied to the electrical connection line. In this case, the removal or the supply of electrical energy by the DC / DC converter by means of the control unit is controllable, wherein the control unit controls the DC / DC converter according to the electrical balance determined by the sensor unit.

The energy supply network may in particular be a public or private, in particular an economically accounted, energy supply network. In operation, ie in the case of solar radiation, a PV system with PV modules generates according to their specific and if necessary material-dependent current / voltage characteristic, a DC voltage and a DC corresponding to the respective operating state, which is converted into AC by means of the supply-network-coupled inverter. In each case, the DC internal resistance of the supply-network-coupled inverter is set by the control logic of the inverter in such a way that a maximum electrical power can be generated in the respectively current operating state of the PV modules. This control strategy is referred to as Maximum Power Point Tracking (MPPT). As a result, the MPPT process results in the grid-coupled inverter being able to reduce the instantaneous actual power of the PV modules by changing its internal electrical resistance to zero power. The utility-coupled inverter, however, is unable to produce more electrical power than the PV modules can provide in their current operating condition at maximum efficiency by the MPPT process. The respective instantaneous maximum power of the PV modules depends essentially on the radiation intensity, the module temperature and the aging state of the modules. If the modules are operated at the MPP point, a further increase in the electrical power of these modules is not possible. Therefore, in a conventional grid-connected PV system, it is possible to reduce the PV power to zero, but not to provide more AC power than is physically possible according to the factors mentioned above.

Due to this connection, grid-connected PV systems are not able to provide electrical energy as needed 24 hours a day. Therefore, it is often attempted to solve the problem by the use of electrical energy storage devices, in particular by the use of batteries.

There is the possibility of a DC coupling of the energy storage between the PV unit and the AC output of the grid-connected inverter. In DC coupling, in the current flow direction before the AC output of the grid-connected inverter, either by means of a bidirectional DC / DC converter or two parallel-connected unidirectional DC / DC converter, electrical power for charging or discharging the battery off or supplied. The advantage of this technology is a favorable higher efficiency compared to a known AC coupling of the energy storage. The disadvantage, however, is that in the prior art, charging or discharging the battery necessitates communication with the central control logic of the utility grid coupled inverter because uncontrolled power draw on the DC side of the utility grid coupled inverter is reduced to current / voltage. May cause constellations in the DC string between the PV unit and the grid-connected inverter that are inconsistent with the power-voltage control implemented in the grid-connected inverter in accordance with the MPPT control method. An uncontrolled entry of electrical power in front of the AC output of the utility grid coupled inverter may result in complete de-energizing of the PV unit. If z. B. the voltage in the electrical connection line during the power input from the battery reaches the standstill voltage of the PV modules, then the power of the PV modules to zero. Conversely, with a power input well below the MPPT operating point of the PV modules, the power potential of the PV modules is not fully utilized because the voltage of the electrical connection line is lower than would correspond to the MPP point. Therefore, in the DC coupling according to the prior art, a communication interface to the control electronics of the grid-connected inverter is necessary so that the use of a battery, the full performance of the PV unit remains unaffected.

This relationship means that the integration of a battery on the DC side of the grid-connected inverter without access to the central control unit of the inverter is only possible with significant losses of the performance of the PV unit or the overall efficiency of the power generation system.

Advantageously, the energy management system according to the invention allows operation of the power generation plant even at reduced power of the energy converter, so that operation of the power generation plant is also possible 24 hours a day and in which the disadvantages of the prior art DC coupling of a connected energy storage can be avoided.

In the energy management system according to the invention for the demand-oriented provision of electrical energy from predominantly renewable energy sources is at least one electrical connection line. an energy converter, such as a photovoltaic unit (PV unit), connected to a power supply-coupled inverter, for example via a T-shaped connection point, a bidirectional DC-DC converter (DC / DC converter). The electrical connection line is installed in a PV Plant also referred to as a PV string, since the PV modules to so-called strings of a PV unit connected in parallel and / or series connected to it. The T-shaped connection point may expediently have a suitable unidirectional blocking element on the side facing the energy converter, which prevents unwanted feedback from the energy storage unit into the energy converter, in particular a diode or a corresponding circuit which prevents such recovery from the energy storage unit into the energy converter , and which is connected to the energy converter in the reverse direction.

The DC / DC converter has a maximum of two power-carrying terminals for one plus and one minus pole. A power-carrying electrical connection is with the. connected electrical connection line and the second power-carrying electrical connection is connected to an energy storage unit, such as a rechargeable battery system or a capacitor unit.

In this way, the bidirectional DC / DC converter is able to conduct electrical energy generated in the energy converter to the energy storage unit and / or to conduct electrical energy from the at least one energy storage unit to the grid-coupled inverter. The DC / DC converter is provided for voltage adjustment between the electrical connection line and the energy storage unit. Furthermore, the DC / DC converter and the energy storage unit are connected via a communication line to the central control unit of the energy management system. There is no communication line or other type of communication structure to the grid-coupled inverter.

The central control unit is connected to a suitable sensor unit, for example an alternating current (AC) sensor in communication connection. The AC sensor is arranged downstream of the supply-network-coupled inverter in the current flow direction, wherein between the supply network coupled inverter and the AC sensor at least one, preferably all, consumers of the relevant electrical balance space are arranged. The sensor unit detects at a predetermined time resolution in the relevant electrical balance space between the consumers of the power generation plant and the grid connection at least the relevant AC grid data: current and / or voltage and / or frequency in each phase. These data are transmitted via the communication line to the central control unit. The evaluation of these data in the central control unit gives the instantaneous electrical energy flow in the predetermined temporal resolution and thus the net electrical balance of the power generation plant. The control unit is thus able to control the DC / DC converter according to the electrical balance determined by the sensor unit. Thus, the internal resistance of the grid-connected inverter via the electrical balance, to which the DC / DC converter is controlled, can be suitably influenced as if the entire energy that is supplied to the supply network coupled inverter input side, would come from the energy converter.

With the energy management system according to the invention described above, the disadvantages of an AC-coupled and a DC-coupled energy storage described above can be avoided, so that thus an operation of a power plant is possible even at greatly reduced operation of the energy converter and so consumers can still be fed with it.

According to an advantageous embodiment, the DC / DC converter can be designed to emulate a current / voltage characteristic of the energy converter when feeding electrical energy into the electrical connection line. Thus, during operation of the DC / DC converter, the MPPT method of the grid-connected inverter, as described above, is not adversely affected and the grid-coupled inverter continues, for example, at night when a PV module does not generate energy, the DC / DC operates Conveniently in terms of the target power supply or removal, according to the relationship of transported current as a function of voltage according to a current / voltage characteristics of the energy converter, so for example a silicon-based photovoltaic cell or other suitable materials with photovoltaic effect.

According to an advantageous embodiment, the electrical connection line may have a unidirectional blocking element, which prevents unwanted feedback from the energy storage unit in the energy converter, in particular a diode or a corresponding circuit that prevents such feedback, which between an output of the energy converter and a connection point of the DC / DC converter is arranged in the electrical connection line and is connected in the reverse direction to the energy converter. In this way, it is possible to prevent the electrical energy fed in by the DC / DC converter from leading to a malfunction of the energy converter and / or of the energy management system, for example, thereby increasing the output voltage of the energy converter.

According to an advantageous embodiment, the sensor unit may comprise at least one AC sensor, the sensor unit preferably detecting at least current and / or voltage and / or frequency of the electrical power at the mains connection with a time resolution of less than 200 msec, preferably less than 100 msec.

The connected consumers of the power generation plant usually operate as AC powered components because they are connected to a conventional power supply to which the power generation plant is connected via the grid-connected inverter. Therefore, it is advantageous if the AC power of the consumer is detected with a suitable time resolution to represent the electrical balance of the power plant.

According to an advantageous embodiment, the energy storage unit may have a rechargeable battery system and / or a capacitor unit and / or a flywheel storage. Storage systems are conceivable which allow electrical energy to be absorbed and stored in suitable form, possibly also as mechanical or chemical energy, and to release the stored energy directly as electrical energy or to convert the stored energy form back into electrical energy and release it.

According to an advantageous embodiment, the DC / DC converter via the second terminal with one or more power generation units, in particular a power generation unit of a fuel cell system, an AC block heating, a DC block heating, a motor generator or the like may be connected. The energy management system may have between the DC / DC converter and the energy storage unit on a DC bus another T-shaped connection point as an electrical connection to further electric power generation units. These power generation units may be, for example, wind turbines, fuel cells, biogas plants, micro-block heating or conventional fossil-powered motor generators. These power generation units are advantageously unidirectional, i. H. operated with power flow to the DC bus out. All of these power generation units are connected to the central control unit of the energy management system.

According to an advantageous embodiment, the one or more power generation units may be operable as constant voltage sources. The operation of the AC / DC or DC / DC converter of the power generation units connected to the DC bus of the energy storage unit takes place with respect to the output voltage to the DC bus of the energy storage unit as a quasi-constant voltage source.

In this way, the energy management system according to the invention is cheap to operate via the controlled by the control unit DC / DC converter.

According to an advantageous embodiment, the energy storage unit and / or the DC / DC converter and / or the inverter for the operation of the one or more power generation units can be controlled via the control unit. The power generation units are not connected to the control unit of the grid-connected inverter and receive from there so also no information and also send no signals there. The control unit controls the advantageous use of the various power generation units according to the current operation of energy converters and consumers according to the current electrical balance determined by the sensor unit.

According to a further aspect of the invention, a power generation plant is proposed, in particular a photovoltaic system, with a DC-coupled energy management system, comprising an energy converter, in particular a photovoltaic unit, which is provided for providing a variable DC power depending on operating and / or environmental conditions, and a power supply coupled inverter , which is provided for feeding one or more consumers and is connected to a grid connection of a power supply network. Furthermore, the power generation plant comprises a control unit, a sensor unit for measuring an electrical balance between consumers and the grid connection, and a DC / DC converter connected to a first connection to an electrical connection line between the energy converter and the grid-coupled inverter and to a second terminal at least one energy storage unit is connected. The control unit is designed for communication with the sensor unit, the energy storage unit and the DC / DC converter. The DC / DC converter is bidirectional, so that electrical energy can be removed from the electrical connection line and / or electrical energy can be supplied to the electrical connection line. In this case, the removal or supply of electrical energy can be controlled by the DC / DC converter by means of the control unit, wherein the control unit controls the DC / DC converter according to the electrical balance determined by the sensor unit.

The electrical connection line may comprise a unidirectional blocking element which prevents unwanted feeding back of the energy storage unit into the energy converter, in particular a diode or a corresponding circuit which prevents such return from the energy storage unit in the energy converter, which between an output of the energy converter and a Connection point of the DC / DC converter is arranged in the electrical connection line and is connected in the reverse direction to the energy converter.

According to a further aspect of the invention, a DC / DC converter for a DC-coupled power management system is proposed, having a first terminal connected to an electrical connection line of a power plant between an energy converter and a grid-coupled inverter and a second terminal connected to at least one energy storage unit is, wherein a removal of electrical energy from the electrical connection line or a supply of electrical energy to the electrical connection line is controllable by means of a control unit. In this case, the control unit controls the DC / DC converter according to the electrical balance determined by a sensor unit between consumers of the power generation system and a mains connection. In this case, at least one load of the power generation plant, preferably all consumers of the power generation plant, are advantageously taken into account for detecting the electrical balance.

According to a further aspect of the invention, a method for operating a power generation plant with a DC coupled energy management system is proposed, comprising detecting the electrical balance between consumers of the power generation plant and a grid connection of a power supply network by means of a sensor unit, controlling a DC / DC converter, the at least an energy storage unit is connected by means of a control unit according to the electrical balance determined by the sensor unit, and the removal or supply of electrical energy by the DC / DC converter to an electrical connection line between an energy converter and a power supply system coupled to the grid.

The operation of the energy management system according to the invention takes place as described below. The sensor unit, preferably designed as an AC sensor, detects with a temporal resolution of in particular less than 200 msec, preferably less than 100 msec in the relevant electrical balance space between the consumers of the power generation plant and the grid connection at least the relevant AC grid data: current, voltage , Frequency in each phase. These data are transmitted via the communication line to the central control unit. The evaluation of this data in the central control unit gives the instantaneous electrical energy flow in the predetermined temporal resolution.

In addition to these data, the central control unit additionally evaluates all further state variables of the further energy storage units and energy generation units connected to the DC bus of the energy storage unit and then decides which operation of the DC / DC converter is to be carried out in the following control interval. The decision of the central control unit is based on the consideration of the state variables of the connected components, taking into account the specific instantaneous performance of the connected components and taking into account the specific costs of the electrical energy caused by the various connected components. The aim is to minimize the total costs of the demand-oriented provision of electrical energy from the energy converter, in particular the renewable energy source, and thereby to optimize the overall economy of the power generation plant.

By controlling the DC / DC converter via the control unit via the electrical balance, which is detected by means of the sensor unit, the internal resistance of the supply-network-coupled inverter can be suitably influenced as if all the energy supplied to the supply network-coupled inverter on the input side is removed from the power supply Energy converter would come.

The bidirectionally formed DC / DC converter then carries out the necessary operation, wherein there are two operating states of the DC / DC converter. These are: to draw electrical energy from the electrical connection line, to supply electrical energy to the electrical connection line.

Thus, during operation of the DC / DC converter, the MPPT method of the grid-connected inverter, as described above, is not adversely affected and the grid-coupled inverter continues, for example, at night when a PV module does not generate energy, the DC / DC operates With respect to the target power supply or removal, according to the relationship of transported current as a function of voltage according to a current / voltage characteristic of the energy converter, so for example a silicon-based photovoltaic cell. Through this The control strategy of the DC / DC converter in no way adversely affects the MPPT control logic of the grid-connected inverter, so that the grid-connected inverter does not detect a difference between the "true" electrical power of the energy converter and the resulting electrical power provided by the energy management system. As a result, any supply network-coupled inverter can be used for the AC supply of any type of renewable electrical energy for the use of the energy management system according to the invention. The invention is therefore particularly suitable for the further integration of renewable electric power generation units, because no special devices for the DC / AC conversion are necessary and the AC feed is thus based on a device technology that has already been operated successfully over many decades.

According to an advantageous embodiment, the operation of the DC / DC converter can take place in parallel with the operation of the energy converter. In this case, in particular both operating states of the DC / DC converter, namely the removal of electrical energy from the electrical connection line, as well as the supply of electrical energy in the electrical connection line, be carried out in parallel to the operation of the energy converter, so that the converted from the supply network inverter Energy may consist partly of the energy supplied by the energy converter and partly of the energy supplied by the energy storage unit.

According to an advantageous embodiment, the energy management system can at least one of the operating states (i) generating electrical energy by the energy converter and supplying electrical energy through the DC / DC converter to the electrical connection line, (ii) generating electrical energy by the energy converter and removing electrical energy perform the DC / DC converter from the electrical connection line, or (iii) supplying electrical energy to the electrical connection line through the DC / DC converter. These operating states of the energy management system result in particular with regard to the joint operation of energy converters and DC / DC converters, and in particular to the two operating states of the DC / DC converter for removing electrical energy from the electrical connection line, as well as the supply of electrical energy in the electrical connection line. The third operating state of the energy management system (iii) supplying electrical energy to the electrical connection line through the DC / DC converter in particular represents the night mode of the power generation plant.

According to an advantageous embodiment, the control unit can control the DC / DC converter with the goal of a zero net electrical balance determined by the sensor unit. Such an operation is advantageous because the energy used by the consumers is completely removed from the operation of the power generation plant and no energy from the power grid, such as a public or private, especially economically balanced network must be removed. As a result, the operation of the consumer with respect to the power generation unit is self-sufficient. On the other hand, no energy is supplied to the power grid, which can be favorable under certain conditions, which may depend on corresponding energy supply contracts. Alternatively, it is also conceivable to choose a different target variable instead of the target quantity of a net electrical balance of zero.

According to another advantageous embodiment, the control unit can also control the DC / DC converter with the aim of maximum power output of the power generation plant on the basis of the available DC power at the input of the supply-network-coupled inverter.

Such an operation of the energy management system may be advantageous if from the power generation plant at the time under the given boundary conditions, such as current weather, condition of the system, current electricity costs, maximum deliverable power to be taken should. Thus, possibly a cost-optimal operation of the power generation plant can be realized.

drawing

Further advantages emerge from the following description of the drawing. In the drawing, an embodiment of the invention is shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

It shows by way of example:

1 a block diagram of a power plant with an energy management system according to an embodiment of the invention.

Embodiment of the invention

The figure shows only an example and is not intended to be limiting.

The only 1 shows a block diagram of a power plant 100 with an energy management system 10 according to an embodiment of the invention.

The power generation plant 100 , which in particular can represent a photovoltaic system, is with the DC-coupled energy management system 10 educated. The power generation plant 100 includes the energy converter 12 in particular, may be a photovoltaic unit, which is provided to provide a variable DC power depending on operating and / or environmental conditions. Next includes the power generation plant 100 the grid-connected inverter 14 which feeds one or more consumers 80 is provided and connected to the mains 20 of the power supply network 200 connected is. At the in 1 shown embodiment are three consumers 81 . 82 . 83 to the line 56 between the exit 18 of the grid-connected inverter 14 and the power connection 20 connected.

The DC coupled energy management system 10 includes the control unit 30 which via the communication line 36 with the sensor unit 32 for measuring an electrical balance between consumers 80 and the power connection 20 of the power supply network 200 connected, as well as the DC / DC converter 22 that with the first connection 24 over the T-shaped connection point 54 to the electrical connection line 16 between the exit 62 of the energy converter 12 and the entrance 28 of the grid-connected inverter 14 as well as with the second connection 26 over the line 60 to the energy storage unit 40 connected. The sensor unit 32 includes at least one AC sensor, wherein the sensor unit 32 preferably at least current and / or voltage and / or frequency of the electrical power between the consumers 80 and the power connection 20 recorded with a temporal resolution less than 200 msec, preferably less than 100 msec.

The energy storage unit 40 may comprise a rechargeable battery system and / or a capacitor unit and / or a flywheel storage.

The electrical connection line 16 the power generation plant 100 has the unidirectional blocking element 52 on, for example, a diode, which is an undesirable feedback from the energy storage unit 40 in the energy converter 12 prevents which between the output 62 of the energy converter 12 and the connection point 54 of the DC / DC converter 22 in the electrical connection line 16 is arranged and in the reverse direction to the energy converter 12 is switched.

The DC / DC converter 22 is bidirectional, so that electrical energy from the electrical connection line 16 removable and / or electrical energy of the electrical connection line 16 can be fed. The removal or supply of electrical energy by the DC / DC converter 22 is by means of the control unit 30 controllable, which control unit 30 the DC / DC converter 22 over the communication line 34 after that of the sensor unit 32 between consumers 80 the power generation plant 100 and the power connection 20 certain electrical balance controls.

The DC / DC converter 22 is formed when feeding electrical energy into the connecting line 16 a current / voltage characteristic of the energy converter 12 replicate.

Next is the DC / DC converter 22 over the second connection 26 at the T-shaped connection point 58 with several power generation units, here with the fuel cell system 41 , the AC block heating system 42 , the DC block heating plant 43 , as well as the motor generator 44 connected, which the additional supply of electrical energy via the DC / DC converter 22 in the electrical connection line 16 and thus in the grid-connected inverter 14 for supplying consumers 80 can serve. The power generation units 41 . 42 . 43 . 44 are operable as constant voltage sources. DC / DC converter 70 and inverters 72 for the operation of the power generation units 41 . 42 . 43 . 44 are also about the control unit 30 over the communication line 38 controllable.

The method of operation of the power generation plant 100 with the DC coupled energy management system 10 involves collecting the electrical balance between consumers 80 the power generation plant 100 and the power connection 20 of the power supply network 200 by means of the sensor unit 32 , controlling the DC / DC converter 22 pointing to the energy storage unit 40 connected by means of the control unit 30 after that of the sensor unit 32 certain electrical balance, and further the removal or supply of electrical energy by the DC / DC converter 22 on the electrical connection line 16 between the energy converter 12 and the utility grid coupled inverter 14 the power generation plant 100 , The operation of the DC / DC converter 22 can parallel to the operation of the energy converter 12 respectively.

The energy management system 10 Thus, in each case at least one of the operating states (i) Generating electrical energy by the energy converter 12 and supplying electrical energy through the DC / DC converter 22 to the electrical connection line 16 , (ii) generating electrical energy by the energy converter 12 and removing electrical energy through the DC / DC converter 22 from the electrical connection line 16 , or (iii) supplying electrical energy to the electrical connection line 16 through the DC / DC converter 22 , To run.

The control unit 30 so can the DC / DC converter 22 with the aim of one of the sensor unit 32 control a specific net electrical balance of zero or other target size. Alternatively, the control unit 30 the DC / DC converter 22 for example, with the aim of maximum power output of the power generation plant 100 based on the available DC power at the input 28 of the grid-connected inverter 14 Taxes.

LIST OF REFERENCE NUMBERS

10

Energy Management System

12

energy converters

14

inverter

16

connecting line

18

output

20

mains connection

22

DC / DC converter

24

first connection

26

second connection

28

entrance

30

control unit

32

sensor unit

34

communication line

36

communication line

38

communication line

40

Energy storage unit

41

The fuel cell system

42

AC thermal power plant

43

DC-thermal power plant

44

motor generator

52

unidirectional blocking element

54

connection point

56

management

58

connection point

60

management

62

output

70

DC / DC converter

72

inverter

80

consumer

81

first consumer

82

second consumer

83

third consumer

100

Power generation plant

200

Power grid

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

• DE 102012022729 A1 [0003]

Claims (16)

DC coupled energy management system ( 10 ) for a power plant ( 100 ), in particular a photovoltaic system, comprising - a control unit ( 30 ), - a sensor unit ( 32 ) for measuring an electrical balance between consumers ( 80 ) of the energy production plant ( 100 ) and a network connection ( 20 ) of an energy supply network ( 200 ), - a DC / DC converter ( 22 ), with a first connection ( 24 ) to an electrical connection line ( 16 ) of the energy production plant ( 100 ) between an energy converter ( 12 ) and a grid-connected inverter ( 14 ) as well as with a second connection ( 26 ) to at least one energy storage unit ( 40 ), the control unit ( 30 ) for communication with the sensor unit ( 32 ), the energy storage unit ( 40 ) and the DC / DC converter ( 22 ), wherein the energy converter ( 12 ) is provided for providing a variable DC power as a function of operating and / or ambient conditions, wherein the grid-connected inverter ( 14 ) for the supply of one or more consumers ( 80 ) and with the mains connection ( 20 ), wherein the DC / DC converter ( 22 ) is bidirectional, so that electrical energy from the electrical connection line ( 16 ) and / or electrical energy of the electrical connection line ( 16 ), wherein the removal or the supply of electrical energy by the DC / DC converter ( 22 ) by means of the control unit ( 30 ) is controllable, which control unit ( 30 ) the DC / DC converter ( 22 ) after that of the sensor unit ( 32 ) controls certain electrical balance. Energy management system according to claim 1, wherein the DC / DC converter ( 22 ) is formed during the supply of electrical energy into the electrical connection line ( 16 ) a current / voltage characteristic of the energy converter ( 12 ). Energy management system according to claim 1 or 2, wherein the electrical connection line ( 16 ) has a unidirectional blocking element ( 52 ), which is an undesired feedback from the energy storage unit ( 40 ) into the energy converter ( 12 ), which between an output ( 62 ) of the energy converter ( 12 ) and a connection point ( 54 ) of the DC / DC converter ( 22 ) in the electrical connection line ( 16 ) is arranged and in the reverse direction to the energy converter ( 12 ) is switched. Energy management system according to one of the preceding claims, wherein the sensor unit ( 32 ) comprises at least one AC sensor, wherein the sensor unit ( 32 ) preferably at least current and / or voltage and / or frequency of the electrical power at the mains connection ( 20 ) recorded with a temporal resolution of less than 200 msec, preferably less than 100 msec. Energy management system according to one of the preceding claims, wherein the energy storage unit ( 40 ) has a rechargeable battery system and / or a capacitor unit and / or a flywheel storage. Energy management system according to one of the preceding claims, wherein the DC / DC converter ( 22 ) via the second port ( 26 ) with one or more power generation units, in particular a power generation unit from a fuel cell system ( 41 ), an AC cogeneration unit ( 42 ), a DC block heating plant ( 43 ), a motor generator ( 44 ) or the like is connected. An energy management system according to claim 6, wherein said one or more power generation units ( 41 . 42 . 43 . 44 ) are operable as constant voltage sources. Energy management system according to claim 6 or 7, wherein the energy storage unit ( 40 ) and / or the DC / DC converter ( 70 ) and / or the grid-connected inverter ( 72 ) for the operation of the one or more power generation units ( 41 . 42 . 43 . 44 ) via the control unit ( 30 ) are controllable. Power generation plant ( 100 ), in particular a photovoltaic system, with a DC-coupled energy management system ( 10 ), in particular according to one of the preceding claims, comprising - an energy converter ( 12 ), in particular a photovoltaic unit, which is provided for providing a variable DC power as a function of operating and / or ambient conditions, - a supply-network-coupled inverter ( 14 ), which is used to feed one or more consumers ( 80 ) and with a network connection ( 20 ) of an energy supply network ( 200 ), - a control unit ( 30 ), - a sensor unit ( 32 ) for measuring an electrical balance between consumers ( 80 ) and the power supply ( 20 ) of the energy supply network ( 200 ), - a DC / DC converter ( 22 ), with a first connection ( 24 ) to an electrical Connection line ( 16 ) between the energy converter ( 12 ) and the grid-coupled inverter ( 14 ) as well as with a second connection ( 26 ) to at least one energy storage unit ( 40 ), the control unit ( 30 ) for communication with the sensor unit ( 32 ), the energy storage unit ( 40 ) and the DC / DC converter ( 22 ), wherein the DC / DC converter ( 22 ) is bidirectional, so that electrical energy from the electrical connection line ( 16 ) and / or electrical energy of the electrical connection line ( 16 ), wherein the removal or the supply of electrical energy by the DC / DC converter ( 22 ) by means of the control unit ( 30 ) is controllable, which control unit ( 30 ) the DC / DC converter ( 22 ) after that of the sensor unit ( 32 ) controls certain electrical balance. Power plant according to claim 9, wherein the electrical connection line ( 16 ) a unidirectional blocking element ( 52 ), which is an undesired feedback from the energy storage unit ( 40 ) into the energy converter ( 12 ), which between an output ( 62 ) of the energy converter ( 12 ) and a connection point ( 54 ) of the DC / DC converter ( 22 ) in the electrical connection line ( 16 ) is arranged and in the reverse direction to the energy converter ( 12 ) is switched. DC / DC converter ( 22 ) for a DC coupled energy management system ( 10 ) according to one of claims 1 to 8, with a first connection ( 24 ) connected to an electrical connection line ( 16 ) of a power plant ( 100 ) according to claim 9 or 10 between an energy converter ( 12 ) and a grid-connected inverter ( 14 ) as well as with a second connection ( 26 ) connected to at least one energy storage unit ( 40 ), wherein a removal of electrical energy from the electrical connection line ( 16 ) or supplying electrical energy to the electrical connection line ( 16 ) by means of a control unit ( 30 ) is controllable, which control unit ( 30 ) the DC / DC converter ( 22 ) after that of a sensor unit ( 32 ) between consumers ( 80 ) of the energy production plant ( 100 ) and a network connection ( 20 ) controls certain electrical balance. Method for operating a power generation plant ( 100 ) according to claim 9 or 10 with a DC coupled energy management system ( 10 ) according to one of claims 1 to 8, comprising - recording the electrical balance between consumers ( 80 ) of the energy production plant ( 100 ) and a network connection ( 20 ) of an energy supply network ( 200 ) by means of a sensor unit ( 32 ), - controlling a DC / DC converter ( 22 ) connected to at least one energy storage unit ( 40 ) is connected by means of a control unit ( 30 ) after that of the sensor unit ( 32 ) specific electrical balance, - withdrawing or supplying electrical energy through the DC / DC converter ( 22 ) on an electrical connection line ( 16 ) between an energy converter ( 12 ) and a grid-connected inverter ( 14 ) of the energy production plant ( 100 ). The method of claim 12, wherein the operation of the DC / DC converter ( 22 ) parallel to the operation of the energy converter ( 32 ) he follows. Method according to one of claims 12 or 13, wherein the energy management system ( 10 ) at least one of the operating states (i) generating electrical energy by the energy converter ( 12 ) and supplying electrical energy through the DC / DC converter ( 22 ) to the electrical connection line ( 16 ), (ii) generating electrical energy by the energy converter ( 12 ) and removing electrical energy through the DC / DC converter ( 22 ) from the electrical connection line ( 16 ), (iii) supplying electrical energy to the electrical connection line ( 16 ) by the DC / DC converter ( 22 ). Method according to one of claims 12 to 14, wherein the control unit ( 30 ) the DC / DC converter ( 22 ) with the aim of one of the sensor unit ( 32 ) controls certain net electrical balance of zero or other target size. Method according to one of claims 12 to 15, wherein the control unit ( 30 ) the DC / DC converter ( 22 ) with the aim of maximizing the output of the power generation plant ( 100 ) based on the available DC power at the input ( 28 ) of the grid-connected inverter ( 14 ) controls.

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