Classifications

• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
  • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
  • G05F1/66—Regulating electric power
  • G05F1/67—Regulating electric power to the maximum power available from a generator, e.g. from solar cell
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J3/00—Circuit arrangements for AC mains or AC distribution networks
  • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
  • H02J3/381—Dispersed generators
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
  • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
  • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
  • H02J2300/20—The dispersed energy generation being of renewable origin
  • H02J2300/22—The renewable source being solar energy
  • H02J2300/24—The renewable source being solar energy of photovoltaic origin
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
  • H02J2300/20—The dispersed energy generation being of renewable origin
  • H02J2300/22—The renewable source being solar energy
  • H02J2300/24—The renewable source being solar energy of photovoltaic origin
  • H02J2300/26—The renewable source being solar energy of photovoltaic origin involving maximum power point tracking control for photovoltaic sources
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy
  • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Definitions

• Inverter in particular as part of a power generation network
• the invention relates to an inverter for converting DC power of a
• Generator in line-compatible AC power, a power generation network with a plurality of inverters, and a method for converting the DC power of a generator into grid-compatible AC power.
• the publication DE102010038941 A1 discloses a combination of several inverters which are operated via a common control such that one of the inverters is operated in the MPP, while the other inverters adjust their power so that the total power of the network corresponds to a predetermined value.
• This solution requires a high communication effort between the participating inverters and the common control.
• it is not always possible to operate a plant of the network permanently in the MPP, in particular when adjusting to a very low control power. It is therefore an object of this invention to provide an inverter capable of compensating, within a power generation network, a power deviation from a predetermined power-down during the determination of an MPP, within the power-generating network being minimized and robust
• the inverter triggers only then a coasting of the characteristic under provision of deviating from the Abregelelleungp red first power profile when the inverter is applied an enable signal.
• the inverter shuts off the characteristic curve by outputting a start signal or an end signal.
• the inverter is configured to provide a second power profile as AC power when receiving a start signal, for example from another inverter of a power generation network, the first power profile having a deviation from the turn-off power P red with a sign that is opposite to one Sign of a deviation of the second power profile of the Abregelel intricate P red .
• the first power profile has a deviation with a positive sign, ie the first power profile comprises increased power values compared to the turn-off power.
• the term power profile is understood to mean a time course of the power fed in, which results from a targeted shutdown of the generator characteristic curve, irrespective of which parameter specification of this shutdown is controlled.
• the shutdown for example, by a time-dependent specification of the generator voltage, the
• the inverter driving off its generator characteristic subsequently sets a current MPP power value P M pp over one
• This value can be transferred to other inverters in the power generation network and used there to change an estimate of the current MPP power value of this other inverter based on the power-down performance. In this way, it is possible to take into account changes in the external conditions of the generation of energy by the generator, for example changes in the radiation, without having to renew the characteristic curve through each inverter. This can significantly reduce the number of scan processes required, for example, when the dropout power is to be selected as a predetermined percentage of the MPP power value or as a MPP power value reduced by a percentage of the rated power, and an off-line power adjustment in short time to change the MPP power value.
• the enable signal, the start signal and / or the end signal can be transmitted via an Internet connection.
• a power generation network according to the invention comprises two or more
• Inverter which are interconnected to exchange the enable signal, the start signal and the end signal.
• a control device is provided, which is connected to the inverters of the power generation network and generates the enable signal.
• the enable signal can be selectively sent to individual or a subgroup of the inverters of the network or only be valid for them.
• one of the inverters can take over this function or the function can be distributed over a subgroup or all inverters.
• the control device or the inverters involved in generating the enable signal determine the order and frequency of the scan process within the power generation network. The mutual triggering of the shutdown of
• Characteristic can be controlled by a token.
• the token is from the
• Inverter which is currently performing a scan process, is passed on to another inverter upon completion, thereby gaining the permission to perform a scan process itself, whereby the receiving inverter can pass the token unused.
• At least one of the inverters is connected to a variable orientation generator and provides the first power profile during a scan process instead of changing the generator voltage by changing the generator orientation.
• the method comprises a departure from the characteristic curve while providing a first power profile deviating from the power-down performance, provided that an enable signal is applied to the inverter.
• the inverter In the case of receiving a start signal, for example the start signal generated by another inverter of a power generation network, the inverter provides a second power profile as AC power, the first power profile having a deviation from the turn-off power with a sign opposite to a sign of a Deviation of the second power profile from the Abregelel intricate is.
• the method is carried out jointly on a first and a second inverter.
• the first characteristic curve is traversed by gradually increasing a nominal value specification for the first inverter, with the second characteristic being traversed in parallel by a step-by-step reduction of a nominal value specification for the second inverter which compensates for the increase.
• the increase in the setpoint specification can be continued until the first inverter can no longer follow the setpoint specification. The highest reached
• Setpoint default can determine the MPP power value for the first inverter.
• the first characteristic curve can be lowered by gradually increasing a setpoint input for the second inverter and the second characteristic can be reduced by stepwise reducing the setpoint input of the second inverter to compensate for a setpoint input for the first inverter ,
• the highest setpoint specification reached determines the MPP power value for the second inverter.
• the various setpoint specifications can be generated and transmitted by a control unit or by one of the two inverters.
• the enable signal, as well as the start signal and the end signal can be configured as independent signals, or be transmitted implicitly by the different setpoint specifications.
• the first transmitted setpoint specification can be interpreted as a start signal or enable signal, and a setpoint input leading back to the shutdown output as the end signal.
• the inverter may be replaced by an inverter group having a plurality of
• the second power profile can be distributed in this embodiment in any way between the individual inverters for deployment.
• FIG. 1 shows an embodiment of an inverter according to the invention
• Fig. 2 is a diagram of a characteristic of a generator with departure paths, such as a
• FIG. 4 shows a power generation system according to the invention with exemplary
• Fig. 5 show power profiles of another embodiment of the invention.
• Fig. 1 shows an inverter 10 according to the invention for converting DC power of a connected generator 1 1, in particular a photovoltaic generator, in AC power, which is transmitted to a connected network 12, for example, a single-phase or a multi-phase, in particular three-phase Network can be.
• a connected generator 1 in particular a photovoltaic generator
• AC power which is transmitted to a connected network 12, for example, a single-phase or a multi-phase, in particular three-phase Network can be.
• a connected network 12 for example, a single-phase or a multi-phase, in particular three-phase Network can be.
• an inverter bridge 13 is used, which has a Scanning unit 14 is controllable in the form that a converted by the inverter bridge 13 power can be adjusted using the scanning unit 14.
• the scanning unit 14 is configured to receive signals transmitted via a bus 17.
• the scanning unit 14 can receive a release signal 15 via a first line, and the scanning unit 14 can send or receive a start signal 16 via a second line. Via the second line, the scanning unit 14 can additionally send or receive an end signal, wherein it is also conceivable that the end signal is transmitted via a separate line.
• the first line and the second line may be separate lines or a common line, in particular one
• the bus 17 includes the Internet and the signals are transmitted via an Internet connection.
• inverters or a control unit not shown may be connected to transmit enable signals, start signals or end signals between inverters or between an inverter and the control unit.
• the scanning unit 14 serves to trigger and control a running off of a characteristic curve of the generator 1 1 in order to determine its MPP power value P M pp, that is, to determine which maximum power the generator 1 1 is capable of providing at a given time , This is particularly important in a regulated state of the inverter 10 to determine a Abregelel intricate in this state, if the reduction is set depending on the maximum possible power.
• the scanning unit 14 is adapted to trigger such a lowering of the characteristic curve only when a release signal 15 is applied to the scanning unit.
• the beginning of the tracing of the characteristic is indicated by a start signal 16, while the end of the tracing of the characteristic is indicated by an end signal.
• the control device ensures that no release signal 15 is transmitted via the bus 17 or applied to the inverter 10.
• the inverter 10 may be configured to count this period as a period
• Fig. 2 shows as a first diagram on the left side of a characteristic curve 20 of a generator 1 1, in which on the Y-axis, the power and on the X-axis, the generator voltage is recorded.
• a second diagram shows two
• the corresponding departure paths 24, 25 of the characteristic curve 20 are illustrated in the first diagram.
• the inverter 10 is initially in a de-regulated state on
• the inverter 10 is initially in a de-regulated state at the operating point 22 at the Abregelel exchange P red .
• the power profile 25 'delivered to the network 12 is increased in the form of a ramp until the MPP 23 is reached.
• an agent signal can be sent and the power is reduced with a ramp until at the operating point 21 the de-regulation power P red is reached again. Since in this case the MPP 23 is also reached during the associated departure path 25, the MPP power value P M pp at the MPP 23 at the end of the shutdown is also known here and can be taken into account in the shutdown power P red .
• FIG. 3 shows an example flow chart for a method according to the invention, in which the inverter 10 first checks whether a start signal 16 from another
• the inverter 10 starts to provide a second, time-varying power profile instead of a constant time-constant turn-off power P red .
• the second power profile is provided until an end signal is received over the bus 17. Thereafter, the inverter 10 returns to providing a time constant drop-out performance.
• the second power profile starting with the start signal 16 can also be provided independently of a reception of an end signal, or the end signal can be generated when the second power profile is completely passed through and transmitted by the bus 17. In the latter variant, then the departure of the first power profile on receipt of an end signal via the bus 17 can be aborted. This includes an embodiment in which the one power profile that was previously completely run off leads to the provision of the end signal and thus to aborting the departure of the respectively different power profile.
• the inverter 10 checks whether an enable signal 15 is applied via the bus 17 and whether it is necessary to shut down the characteristic curve. If both are the case, the inverter 10 sends a start signal 16 and starts to run the characteristic curve 20 to provide a first power profile. Upon completion of the deceleration of the characteristic curve 20, the inverter 10 sends an end signal and returns to the regulated state, wherein the Abregelel intricate preferably based on the MPP power value P M pp, which was redetermined by the departure of the characteristic. Optionally, the inverter 10 provides this updated MPP power value P M pp over a separate one
• Inverters available. These inverters can adjust their depletion power value P r e d using this updated MPP power value P M pp, for example, to account for changes in irradiance.
• a power generation network 140 according to the invention according to FIG. 4, the interaction of several inverters using the method according to the invention is illustrated by way of an example.
• a first inverter 100, a second inverter 110 and a third inverter 120 are connected to each other via a bus 17.
• the enable signal 105, 15, 125 or the start signal 106, 16, 126 and associated end signals between the inverters can be transmitted and received by means of scan units 104, 114, 124.
• a control device 130 is connected, which can be used, for example, by means of the start signals 106, 16, 126 and the end signals corresponding release signals 105, 1 15, 125 to produce, wherein release signals can be valid both specific to the respective inverter as well as unspecific for all inverters. Accordingly, the controller 130 may provide both a single inverter enable signal, a group of inverters, or all
• controller 130 may co-determine or set the order and frequency with which the inverters of the
• Energy generation network 140 depart their respective characteristics.
• the inverters determine this sequence with each other. This can be done, for example, by passing a token between the inverters.
• the order may also result without coordination between the inverters in that each inverter determines the time at which it will depart its characteristic, if an enable signal is present. Therefore, the controller 130 within the power generation network 140 may also be absent.
• Each of the inverters 100, 110, 120 converts a DC power of a connected generator 100, 1 1 1, 121, each associated with the inverter
• Inverter bridge 103, 1 13, 123 in an AC power and feeds them into a connected network 12 a.
• the power to be converted can vary over the respective
• Scanning unit 104, 1 14, 124 of the inverter are controlled in response to the received signals.
• FIG. 4 An exemplary performance curve, which results from a sequence of the method according to the invention, is shown in the right-hand part of FIG. 4 in the form of three diagrams which are assigned to one of the three inverters 100, 110, 120 and in which Axis is the time and the Y-axis the power is plotted.
• the right upper diagram here is the inverter 100, the right middle diagram that
• Inverter 1 10 and the lower right diagram associated with the inverter 120 In a phase I, all inverters are in the regulated state and each provide a shutdown power P red ready. At a release time t F, an enable signal is present at least at the first inverter 100. At a start time t s at which phase II begins, the first inverter 100 sends a start signal 106 and starts its
• the first power profile 108 comprises a linear increasing
• the second phase II ends at an end time t E, at which the inverter 100 is sent an end signal and returns to a down-regulated state, the inverter 100 provides in the subsequent phase III a modified Abregel inconvenience that during the Traversing the characteristic curve certain current MPP power value P M pp considered.
• the power profile 1 18 of the second inverter 1 10 is shown.
• the second inverter 1 10 receives the start signal of the first inverter 100 and provides a second power profile 1 18 at its output. In the example shown, the converter power decreases linearly with time.
• the second inverter 1 10 receives the end signal of the first
• Abregeliere P red is adjusted in dependence on a supplied from the first inverter 100 current MPPs power value.
• the second power profile 1 18 of the second inverter 1 10 compensates for the deviation of the first power profile 108 of the first inverter 100 from the respective turn-off power P red , so that the sum of the power outputs of both inverters essentially or exactly precedes the sum of the turn-off power P red corresponds to the start time t s . In this way it is avoided that the departure of the characteristic curve for determining a current MPP power value P M pp leads to a deviation of the cumulative power output of the power generation system 140 from the specifications of the trim control.
• the second power profile of the compensating one can be shown in an alternative embodiment, not shown Inverter 1 10 an initially falling power ramp, and then have an increasing power ramp, wherein the change between the power ramps takes place upon receipt of the center signal.
• the bottom right diagram shows the power profile of the third inverter 120.
• the third inverter 120 does not leave its de-energized state, so that its power profile 128 is the time constant value of its
• Control power P red maintains.
• the third inverter 120 therefore does not participate in the compensation of a power deviation of one of the inverters of the power generation system 140 during the execution of a characteristic in this example.
• the third inverter 120 also adjusts its shutoff power P red as a function of the current MPP power value transmitted by the first inverter 100.
• Power generation network 140 are compensated together.
• the contribution to the compensation of the power deviation can be made between the participating inverters be equally distributed or distributed appropriately weighted.
• a fixed assignment between inverters can be made in which it is determined which inverter or which subgroup of the inverter compensates for the different power of another inverter of the network. This can be implemented simply by giving the transmitted start signal a
• the first power profile during the running of the characteristic, as well as possible is predetermined and not or only slightly determined by the course of the characteristic.
• the course of the first power profile does not depend on the curve of the characteristic, but the course of the characteristic determines only the duration between the
• Deviation is achievable, is waived here in favor of a more feasible running off the characteristic to a complete compensatability.
• the generator characteristic curve is traversed within an inverter group having a plurality of individual inverters
• Power generation network 140 in a coordinated manner such that the
• inverters 100 and 110 of FIG. 4 form such a group 150 as a single inverter. Exemplary ones are shown in FIG.
• Embodiment shown wherein the upper diagram shows the first power profiles 108 ', 1 18' of the group 150 of the inverter 100, 1 10 as a single inverter.
• the lower diagram shows the second power profile 128 'of the inverter 120, which shows the combined power profile 158 of the group 150 as the sum of the first power profiles 108', 1 18 'compensated.
• the inverter 100 first starts to lower its characteristic curve in the direction of its MPP by an increasing power ramp, and a start signal 106 is generated. Upon reaching the MPP at the time t- ⁇ reduces the
• Inverter 100 by means of a sinking power ramp its power output until the Abregeliere P red is reached again and the inverter 100 changes to the regulated state.
• t- ⁇ begins the inverter 1 10 to increase its power over a ramp until it reaches its MPP at time t 2 and changes to a decreasing power ramp.
• the inverter 1 10 again reaches the regulated state and an end signal is generated.
• the group 150 behaves in a manner comparable to a single inverter according to the invention by delivering a combined first power profile 158 between a start signal and an end signal. The deviation of the combined power profile 158 from the
• Discharge power P red of group 150 is compensated by the inverter 120 by delivering a second power profile 128 'between the times of the start signal and the end signal, the inverter 120 optionally being responsive to center signals to the
• Times t- ⁇ , t 2 can respond by adjusting the profile profile.
• the start signal and the end signal can basically be of any type
• Single inverters of the group 150 are generated, wherein start signal and end signal are generated by the same or different inverters.
• the single inverter sends the start signal, which first moves off its characteristic, and sends the end signal that single inverter, which finally leaves its characteristic.
• the intermediate points in time t- 1 , t 2 can be tuned by exchanging middle signals or the individual inverters involved determine these points in time
• the beginning of the departure of the characteristics of a single inverter can be selected independently of the time of reaching an MPP by another single inverter.
• the tracing off of the characteristic curve or the provision of a power profile is realized in that the control unit 130 or one of the inverters of a
• the inverter attempts to provide a power that meets the setpoint and returns the result to the sending unit.
• the result can be transmitted, for example, in the form of an achieved power value or in the form of a logical signal that signals complete achievement of the desired value.
• the following sent setpoint value can be incrementally increased until the Inverter signals that it can not reach the setpoint.
• the last setpoint reached can then be understood as MPP power value P M pp.
• a second setpoint value is sent to a second inverter (or a plurality of setpoint values to a plurality of inverters) together with the transmission of a setpoint value exceeding the cutoff power to the first inverter, which is reduced compared to the turndown output, so that the total power of the power generation network remains constant or nearly constant.
• the inverter can be gradually returned to the shutdown capacity by setting new setpoint values, whereby the reduction to the shutdown capacity can not be ruled out with a single step.
• the power 200 of the first inverter is gradually increased until it can no longer follow the setpoint specification at the time t- ⁇ .
• the power of the second inverter 210 is gradually reduced in compensating steps, so that the total power 220 remains constant. As a result arises after the time t- ⁇ a
• the time-delayed departure of the characteristic curves within the group 150 already leads to a reduction of the maximum power deviation of the combined power profile of the group from the common power-off performance of the group compared to the case of simultaneous performance of the characteristic curves by all or several inverters of the group leads.

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• Engineering & Computer Science (AREA)
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• Supply And Distribution Of Alternating Current (AREA)
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• 2014
  • 2014-01-22 DE DE102014100690.9A patent/DE102014100690A1/de not_active Withdrawn
• 2015
  • 2015-01-20 JP JP2016547175A patent/JP6369960B2/ja active Active
  • 2015-01-20 ES ES15701158.6T patent/ES2672921T3/es active Active
  • 2015-01-20 CN CN201580005539.9A patent/CN106463969B/zh active Active
  • 2015-01-20 WO PCT/EP2015/050932 patent/WO2015110400A1/de not_active Ceased
  • 2015-01-20 EP EP15701158.6A patent/EP3097624B1/de active Active
• 2016
  • 2016-07-19 US US15/213,439 patent/US10355491B2/en active Active

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