CN103326350A - Converter controller, energy conversion system, photovoltaic energy conversion system and method - Google Patents

Converter controller, energy conversion system, photovoltaic energy conversion system and method Download PDF

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Publication number
CN103326350A
CN103326350A CN2012100806235A CN201210080623A CN103326350A CN 103326350 A CN103326350 A CN 103326350A CN 2012100806235 A CN2012100806235 A CN 2012100806235A CN 201210080623 A CN201210080623 A CN 201210080623A CN 103326350 A CN103326350 A CN 103326350A
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China
Prior art keywords
signal
isolated island
energy
protection module
output
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CN2012100806235A
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CN103326350B (en
Inventor
公茂忠
谭卓辉
刘云峰
邬雪琴
朱慧斌
大卫.史密斯
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General Electric Co
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General Electric Co
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Priority to CN201210080623.5A priority Critical patent/CN103326350B/en
Priority to PCT/US2013/033062 priority patent/WO2013142553A2/en
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    • 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
    • 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
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • 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
    • H02J3/388—Islanding, i.e. disconnection of local power supply from the network
    • 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
    • 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
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)
  • Control Of Electrical Variables (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The invention discloses an energy conversion system which comprises a converter device and a converter controller. The converter device is used for converting input energy provided by an energy source into output energy, and the converter controller is used for adjusting the active component and the reactive component of the output energy. The converter controller comprises an island protection module which is used for receiving electrical parameter values detected by the output end of the converter device, generating island disturbing signals and disturbing compensating signals at least according to the measured electrical parameter values, and acting the island disturbing signals and the disturbing compensating signals to be used for adjusting one or both of the active component and the reactive component of the output energy, and therefore the measured electrical parameter values can be moved outside a normal range when an island condition happens.

Description

Inverter controller, energy conversion system, photovoltaic energy converting system and method
Technical field
Execution mode disclosed by the invention relates to energy conversion system and method, particularly a kind of system and method that the isolated island situation of this energy conversion system is detected.
Background technology
Electricity generation system, particularly distributed generation system (for example, photovoltaic generating system and wind generator system etc.) exist so-called " isolated island " operation conditions, its refer to distributed generation system with main electrical network disconnect is electrically connected after, still a lasting part to electric system provides electric energy.The electricity generation system of moving under " isolated island " situation can cause the misgivings of some secure contexts.Wherein a kind of misgivings are to lose or break away from when connecting when electrical network, are not recognized that its part of keeping in repair still when the electric energy that the reception electricity generation system provides, may be subjected to safe infringement if send with charge free the personnel that make working service.Another misgivings is when electrical network trips, this electrical network can lose the voltage of the electric energy that electricity generation system is sent and the control of frequency, therefore, when electrical network recovers again, between line voltage and current transformer output voltage, may there be larger phase difference, and large phase difference may cause that larger impulse current flows to electricity generation system, thereby may damage the interior DC-to-AC converter of electricity generation system etc.
Industry has developed to be made some industrial standards (for example, IEEE1547 and UL1741) and solves above-mentioned safety worries.Usually; these industrial standards require electricity generation system need to possess anti-islet operation function; also be; can detect by the protection mechanism of special setting the islet operation situation; and can be in the regular hour scope after detecting the islet operation situation (for example, in 2 seconds) disconnect connection (perhaps stopping to local load supplying) between electricity generation system and the local load.Basic, existing island detection method can be divided into two classes.The first kind is the passive type detection method, its voltage or frequency by detecting passively the electricity generation system output, and when the measured value of detecting voltage or frequency surpasses default threshold value or default threshold range, carry out corresponding isolated island fence operation.The Equations of The Second Kind island detection method is the active detection method, it is by (for example introducing a less disturbing signal to system on one's own initiative, the frequency disturbance signal, meritorious disturbing signal or idle disturbing signal), then under the effect of positive feedback mechanism ground, voltage or the frequency of electricity generation system output are shifted out default threshold range, thereby realize the detection of islet operation.Yet above-mentioned two kinds of detection methods all exist non-surveyed area (Non-Detection Zone, NDZ) problem.Non-surveyed area generally betides between electricity generation system and the load under the situation that has coupling, and when matching to a certain degree, no matter be all can't detect the isolated island situation with the active detection method or with the passive type detection method.
Therefore, be necessary to provide a kind of improved system and method to solve above-mentioned technical problem.
Summary of the invention
Because above-mentioned technical problem, one aspect of the present invention is to provide a kind of energy conversion system.This energy conversion system comprises converter device and inverter controller.This converter device is configured for the input power conversion that energy source is provided and becomes the output energy; This inverter controller and this converter device are electrically connected, and this inverter controller is configured for real component and the idle component of regulation output energy.This inverter controller comprises the isolated island protection module, and the output of this isolated island protection module and this converter device electrically communicates to connect.This isolated island protection module is configured to receive the measured electrical parameter values of this converter device output, and produces isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least.This isolated island protection module also is configured to this isolated island disturbing signal and disturbance compensation signal function are become to regulate in this output energy any one in the real component and idle component or all, shifts out outside the critical field with the electrical parameter values that will measure when the generation isolated island situation.
In some embodiments, in the energy conversion system that this provides, this isolated island protection module comprises the frequency change detecting unit, disturbance generation unit and compensating unit.This frequency change detecting unit is configured for and receives the frequency signal that the phase-locked loop apparatus in this energy conversion system obtains, and produces frequency variation signal based on this frequency signal.This disturbance generation unit is configured to receive this frequency variation signal, and produces this isolated island disturbing signal based on this frequency variation signal, shifts out normal frequency range with the frequency values that will export energy.This compensating unit and this disturbance generation unit are electrically connected, and this compensating unit is configured for and produces this disturbance compensation signal, to be used for compensation by the caused unexpected variable quantity of isolated island disturbing signal.
In some embodiments, in the energy conversion system that provides, this isolated island disturbing signal comprises reactive current disturbing signal or reactive power disturbance signal.
In some embodiments, in the energy conversion system that provides, this isolated island disturbing signal comprises reactive current disturbing signal and reactive power disturbance signal.
In some embodiments, in the energy conversion system that provides, this disturbance compensation signal comprises q shaft voltage compensating signal.
In some embodiments, in the energy conversion system that provides, this compensating unit also is configured to produce disturbance overcompensation signal.When the isolated island situation occurs, this disturbance overcompensation signal node should the isolated island disturbing signal so that the frequency of this converter device output accelerates to shift out normal frequency range.
In some embodiments, in the energy conversion system that provides, this isolated island protection module further comprises frequency change rate detecting unit and dynamic gain adjustment unit.This frequency change rate detecting unit is configured for based on this frequency variation signal and produces the frequency change rate signal; This dynamic gain adjustment unit and this frequency change rate detecting unit are electrically connected, and this dynamic gain adjustment unit is configured to produce corresponding dynamic gain signal based on this frequency change rate signal.This dynamic gain signal is applied this disturbance generation unit, to be used for dynamically adjusting the amplitude of the isolated island disturbing signal that this disturbance generation unit produced.
In some embodiments, in the energy conversion system that provides, this isolated island protection module comprises the change in voltage detecting unit, disturbance generation unit and compensating unit.This change in voltage detecting unit is configured for and receives the voltage signal that the voltage transformation module in this energy conversion system obtains, and produces voltage change signal based on this voltage signal.This disturbance generation unit is configured to receive this voltage change signal, and produces this isolated island disturbing signal based on this voltage change signal, shifts out normal voltage range with the magnitude of voltage that will export energy.This compensating unit and this disturbance generation unit are electrically connected, and this compensating unit is configured for and produces this disturbance compensation signal, to be used for compensation by the caused unexpected variable quantity of isolated island disturbing signal.
In some embodiments, in the energy conversion system that provides, this disturbance compensation signal comprises d shaft voltage compensating signal.
In some embodiments, in the energy conversion system that provides, this compensating unit can also be configured to produce disturbance overcompensation signal.When the isolated island situation occurs, this disturbance overcompensation signal node should the isolated island disturbing signal so that the voltage of this converter device output accelerates to shift out normal voltage range.
In some embodiments, in the energy conversion system that provides, this isolated island protection module further comprises voltage change ratio detecting unit and dynamic gain adjustment unit.This voltage change ratio detecting unit is configured for based on this voltage change signal and produces the voltage change ratio signal.This dynamic gain adjustment unit and this voltage change ratio detecting unit are electrically connected, this dynamic gain adjustment unit is configured to produce corresponding dynamic gain signal based on this voltage change ratio signal, this dynamic gain signal is applied this disturbance generation unit, to be used for dynamically adjusting the amplitude of the isolated island disturbing signal that this disturbance generation unit produced.
Another aspect of the present invention is to provide a kind of energy conversion system.This energy conversion system comprises converter device and inverter controller.This converter device is configured for the input power conversion that energy source is provided and becomes the output energy; This inverter controller and this converter device are electrically connected, and this inverter controller is configured for real component and the idle component of regulation output energy.This inverter controller comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured frequency variation signal of this converter device output and frequency change rate signal, and produces isolated island disturbing signal and disturbance compensation signal according to the frequency variation signal of this measurement and frequency change rate signal at least.
Another aspect of the present invention is to provide a kind of energy conversion system.This energy conversion system comprises converter device and inverter controller.This converter device is configured for the input power conversion that energy source is provided and becomes the output energy; This inverter controller and this converter device are electrically connected, and this inverter controller is configured for real component and the idle component of regulation output energy.This inverter controller comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured voltage change signal of this converter device output and voltage change ratio signal, and produces isolated island disturbing signal and disturbance compensation signal according to the voltage change signal of this measurement and voltage change ratio signal at least.
Another aspect of the present invention is to provide a kind of energy conversion system.This energy conversion system comprises converter device and inverter controller.This converter device is configured for the input power conversion that energy source is provided and becomes the output energy; This inverter controller and this converter device are electrically connected, this inverter controller comprises the first control loop and the second control loop, this first control loop is configured for the real component of regulating this output energy, and this second control loop is configured to regulate the idle component of this output energy.This inverter controller also comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this converter device output, and produce isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least, this isolated island protection module also is configured to this isolated island disturbing signal is applied to this second control loop, so that the idle component of this output energy is done disturbance.This isolated island protection module also is configured to this disturbance compensation signal function to this second control loop, the voltage instruction that this second control loop is produced compensates, and keeps stable with the real component of keeping this first control loop when acting on this isolated island disturbing signal.
Another aspect of the present invention is to provide a kind of energy conversion system.This energy conversion system comprises converter device and inverter controller.This converter device is configured for the input power conversion that energy source is provided and becomes the output energy; This inverter controller and this converter device are electrically connected, this inverter controller comprises the first control loop and the second control loop, this first control loop is configured for the real component of regulating this output energy, and this second control loop is configured to regulate the idle component of this output energy.This inverter controller also comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this converter device output, and produces isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least.This isolated island protection module also is configured to this isolated island disturbing signal is applied to this first control loop, so that the real component of this output energy is done disturbance, this isolated island protection module also is configured to this disturbance compensation signal function to this first control loop, the voltage instruction that this first control loop is produced compensates, and keeps stable with the idle component of keeping this second servo loop when acting on this isolated island disturbing signal.
Another aspect of the present invention is to provide a kind of inverter controller, and it is configured for the control converter device and carries out the power conversion operation.This inverter controller comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this converter device output, and produce isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least, this isolated island protection module also is configured to this isolated island disturbing signal and disturbance compensation signal function are become to regulate in this output energy any one in the real component and idle component or all, shifts out outside the critical field with the electrical parameter values that will measure when the generation isolated island situation.
Another aspect of the present invention is to provide a kind of inverter controller, and it is configured for the control converter device and carries out the power conversion operation.This inverter controller comprises the first control loop and the second control loop, this first control loop is configured for the real component of regulating the output energy that this converter device provides, and this second control loop is configured to regulate the idle component of the output energy that this converter device provides.This inverter controller also comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this converter device output, and produces isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least.This isolated island protection module also is configured to this isolated island disturbing signal is applied to this second control loop, so that the idle component of this output energy is done disturbance, this isolated island protection module also is configured to this disturbance compensation signal function to this second control loop, the voltage instruction that this second control loop is produced compensates, and keeps stable with the real component of keeping this first control loop when acting on this isolated island disturbing signal.
Another aspect of the present invention is to provide a kind of inverter controller, and it is configured for the control converter device and carries out the power conversion operation.This inverter controller comprises the first control loop and the second control loop, this first control loop is configured for the real component of regulating the output energy that this converter device provides, and this second control loop is configured to regulate the idle component of the output energy that this converter device provides.This inverter controller also comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this converter device output, and produces isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least.This isolated island protection module also is configured to this isolated island disturbing signal is applied to this second control loop, so that the idle component of this output energy is done disturbance.This isolated island protection module also is configured to this disturbance compensation signal function to this second control loop, the voltage instruction that this second control loop is produced compensates, and keeps stable with the real component of keeping this first control loop when acting on this isolated island disturbing signal.
Another aspect of the present invention is to provide a kind of method for energy conversion system being carried out the isolated island detection.The method comprises the steps: to receive the measured electrical quantity of this energy conversion system output at least; At least produce isolated island disturbing signal and disturbance compensation signal based on this electrical quantity; Act on this isolated island disturbing signal, when the isolated island situation occurs, this electrical quantity is shifted out outside the normal range (NR); And act on this disturbance compensation signal, to compensate by the caused unexpected variable quantity of isolated island disturbing signal.
Another aspect of the present invention is to provide a kind of method for energy conversion system being carried out island protect.The method comprises the steps: to receive the measured electrical quantity of this energy conversion system output at least; At least produce isolated island disturbing signal and disturbance compensation signal based on this electrical quantity; Act on this isolated island disturbing signal, when the isolated island situation occurs, this electrical quantity is shifted out outside the normal range (NR); Act on this disturbance compensation signal, to compensate by the caused unexpected variable quantity of isolated island disturbing signal; And when the measured electrical quantity of this output is judged to be outside this normal range (NR), make this energy conversion system stop to export energy.
Another aspect of the present invention is to provide a kind of photovoltaic energy converting system.This photovoltaic energy converting system comprises dc bus, photovoltaic current transformer and photovoltaic controller.This dc bus is configured for and receives the direct current energy that the photovoltaic energy source provides.This photovoltaic current transformer is configured to convert the direct current energy at this dc bus place to AC energy.This photovoltaic controller comprises the isolated island protection module, the output of this isolated island protection module and this photovoltaic current transformer electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this photovoltaic current transformer output, and at least according to electrical parameter values generation isolated island disturbing signal and the disturbance compensation signal of this measurement, this isolated island protection module also is configured to become the electrical parameter values that will measure when the isolated island situation occurs to shift out outside the critical field with the disturbance compensation signal function this isolated island disturbing signal.
In some embodiments, in the energy conversion system that provides, this photovoltaic energy converting system also comprises the maximum power point tracking device, and this maximum power point tracking device is configured to produce the direct voltage reference signal based on the photovoltaic voltage signal and the photovoltaic current signal that measure at this place, photovoltaic energy source.Wherein, when the isolated island situation occurs, this this direct voltage reference signal of isolated island disturbing signal bypass.
Another aspect of the present invention is to provide a kind of photovoltaic energy converting system.This photovoltaic energy converting system comprises dc bus, photovoltaic current transformer and photovoltaic controller.This dc bus is configured for and receives the direct current energy that the photovoltaic energy source provides.This photovoltaic current transformer is configured to convert the direct current energy at this dc bus place to AC energy.This photovoltaic controller comprises d axle control loop and q axle control loop, this d axle control loop is configured to regulate the real component in this photovoltaic current transformer output AC energy, and this q axle control loop is configured to regulate the idle component in this photovoltaic current transformer output AC energy.This photovoltaic controller also comprises the isolated island protection module, and the output of this isolated island protection module and this photovoltaic current transformer electrically communicates to connect.This isolated island protection module is configured to receive the measured electrical parameter values of this photovoltaic current transformer output, and produces isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least.This isolated island protection module also is configured to this isolated island disturbing signal is applied to this d axle control loop, so that the real component of this output energy is done disturbance.This isolated island protection module also is configured to this disturbance compensation signal function is arrived this d axle control loop, and the voltage instruction that this d axle control loop is produced compensates, and keeps stable with the idle component of keeping this q axle control loop when acting on this isolated island disturbing signal.
Energy conversion system provided by the invention; inverter controller; the photovoltaic energy converting system; islet operation detecting method; and the islet operation guard method etc.; by introducing on one's own initiative the isolated island disturbing signal target electrical quantity of energy conversion system output is carried out disturbance; detect with convenient islet operation situation to this energy conversion system; and in the process of introducing the isolated island disturbing signal; the unexpected variable quantity that the isolated island disturbing signal is caused by disturbance compensation signal dynamics ground compensates; so that the isolated island disturbing signal is carried out disturbance to the target electrical quantity more effectively, to detect rapidly and accurately the islet operation situation.In addition, in the mechanism of disturbing signal, can also accelerate the movement of target electrical quantity by overcompensation mechanism, to shorten isolated island detection time.Further, can also adjust mechanism by dynamic gain, dynamically adjust the amplitude of isolated island disturbing signal, to accelerate the isolated island testing process and to keep system stability.
Description of drawings
Be described for embodiments of the present invention in conjunction with the drawings, the present invention may be better understood, in the accompanying drawings:
Figure 1 shows that the module diagram of a kind of execution mode of energy conversion system;
Figure 2 shows that the module diagram of a kind of execution mode of the photovoltaic energy converting system that disposes improved isolated island protection module;
Figure 3 shows that the detailed module diagram of a kind of execution mode of isolated island protection module shown in Figure 2;
Figure 4 shows that the detailed module diagram of a kind of execution mode of current regulator shown in Figure 3 and dynamic compensation unit;
Figure 5 shows that the detailed module diagram of a kind of execution mode of current regulator shown in Figure 3 and dynamic overcompensation unit;
Figure 6 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module shown in Figure 2;
Figure 7 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module shown in Figure 2;
Figure 8 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module shown in Figure 2;
Figure 9 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module shown in Figure 2;
Figure 10 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module shown in Figure 2;
Figure 11 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module shown in Figure 2;
Figure 12 shows that the detailed module diagram of a kind of execution mode of current regulator shown in Figure 11 and dynamic compensation unit;
Figure 13 shows that the detailed module diagram of a kind of execution mode of current regulator shown in Figure 11 and dynamic overcompensation unit;
Figure 14 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module shown in Figure 2;
Figure 15 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module shown in Figure 2;
Figure 16 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module shown in Figure 2;
Figure 17 shows that the module diagram of the another kind of execution mode of the photovoltaic energy converting system that disposes improved isolated island protection module; And
Figure 18 shows that islet operation detects or the flow chart of a kind of execution mode of guard method.
Embodiment
One or more execution mode that the present invention discloses relates to energy conversion system, and particularly active alone island detection method and the energy conversion system that can carry out this active alone island detection method are with detection and the protection of carrying out the isolated island situation.Here so-called " active alone island detection method " refers to by having a mind to or introducing artificially or inject a less disturbance quantity to the control structure of system; break the equilibrium condition of system; force one or more target electrical quantity of energy conversion system output to change; be beneficial to find or detect the islet operation situation of system, and provide protection to system and load.Further, on the basis of active alone island detection method, that the present invention proposes is a kind of " isolated island disturbance compensation mechanism " or " isolated island disturbance compensation algorithm " or " isolated island disturbance compensation method ", should " isolated island disturbance compensation mechanism; algorithm or method " can effectively eliminate or reduce usually to be present in traditional energy generating system by carrying out, the non-detection zone in the distributed generation system that local load connects is for example arranged." the isolated island disturbance compensation mechanism; algorithm or method " here mentioned refers to a kind of controlling mechanism or control algolithm, it can produce corresponding disturbance compensation signal based on the isolated island disturbing signal in the process of carrying out, and with the control loop of this disturbance compensation signal function to system, to eliminate, the unexpected variable quantity of offsetting or reducing to cause owing to effect isolated island disturbing signal.For example, this unexpected variable quantity can be unexpected meritorious variable quantity, and this unexpected meritorious variable quantity may be owing to after for example q axle control loop is introduced reactive current or reactive power disturbance signal, and produce at d axle control loop.In traditional energy conversion system or distributed generation system, if this unexpected variable quantity is not compensated, this unexpected variable quantity can slow down the isolated island disturbing signal in the reverse direction to the disturbance of target electrical quantity, thereby is not effective so so that the detection of isolated island disturbance becomes." the isolated island disturbing signal " here mentioned may also be referred to as the perturbation signal, it is a small-signal, is introduced into or is injected in the control loop of system, under the prerequisite that does not affect the normal power generation the output of process quality of power supply, (for example change one or more electrical quantity of energy conversion system output, voltage, frequency, phase place, impedance, harmonic wave, active power and/or reactive power etc.), thereby when breaking away from energy conversion system, electrical network more easily detects the isolated island situation.
In some embodiments, by the disturbance compensation signal that this " isolated island disturbance compensation mechanism " produces and acts on, can offset or eliminate because the caused unexpected variable quantity of isolated island disturbing signal exactly well.In other embodiments, this disturbance compensation signal can produce and act on by specific mode, it not only eliminates unexpected variable quantity, and can play positive feedback effect to the movement of target electrical quantity, also namely, the disturbance effect with the isolated island disturbing signal is consistent the movement of acceleration target electrical quantity, so that the target electrical quantity can shift out normal threshold range more quickly, such compensation way also can be called " isolated island disturbance overcompensation mechanism ".
Further, in some embodiments, as the mode that can replace or on the basis of " the isolated island disturbance compensation mechanism " of foregoing description, this energy conversion system can also be carried out " dynamic gain is adjusted mechanism ", when connecting to break away from electrical network, detect faster the islet operation situation.Refer in the production process of isolated island disturbing signal this so-called " dynamic gain is adjusted mechanism ", according to dynamic or adjustable yield value of rate of change effect of observed target electrical quantity." dynamic or adjustable yield value " can for a continuous variable (also be referred in this, the corresponding target electrical quantity rate of change value of yield value), also can be a discrete variable (also namely, corresponding one a section target electrical quantity rate of change value of yield value or corresponding a plurality of target electrical quantity rate of change value).For example, when the stage was injected the isolated island disturbing signal in early days, the rate of change of target electrical quantity may be smaller, and can act on a relatively large yield value this moment, to accelerate the skew of target electrical quantity; And when mid-term or later stage injection isolated island disturbing signal, because the rate of change of this target electrical quantity may be relatively large under the effect of positive feedback, can suitably reduce yield value this moment, to keep Systems balanth.
Carry out detection and the protection of islet operation situation by carrying out " isolated island disturbance compensation mechanism " proposed by the invention, the present invention can obtain technological merit or the technique effect that reduces non-detection zone at least.By reducing non-detection zone, can become more reliable and accurate so that isolated island detects, better safety guarantee is provided also can for the personnel that carry out working service, also can avoid simultaneously because the impact damage that the power system restoration DC-to-AC converter suffers.In addition, owing to can eliminate or reduce unexpected variable quantity by carrying out " isolated island disturbance compensation mechanism ", therefore can introduce the disturbing signal of less and carry out the isolated island detection, reduce disturbing signal to the technique effect of systematic influence to obtain.Further technique effect or technological merit are: by carrying out disturbance overcompensation mechanism, perhaps dynamic gain is adjusted mechanism, and perhaps its combination can be shortened detection time of isolated island situation.
One or more embodiment of the present invention below will be described.At first it is to be noted, in the specific descriptions process of these execution modes, in order to carry out brief and concise description, this specification can not all be done detailed description to all features of the execution mode of reality.Should be understandable that; in the actual implementation process of any one execution mode; as in the process of any one engineering project or design object; in order to realize developer's objectives; perhaps in order to satisfy System Dependent or commercial relevant restriction; usually can make various concrete decision-makings, and this can change to another kind of execution mode from a kind of execution mode also.In addition, it will also be appreciated that, although the effort of having done in this development process may be complicated and tediously long, yet for those of ordinary skill in the art relevant with content disclosed by the invention, some designs that carry out on the basis of the technology contents that discloses in the disclosure, make or production etc. changed just conventional technological means, not should be understood to content of the present disclosure insufficient.
Unless define in addition, the technical term that uses in the present specification and claims or scientific terminology should be the ordinary meaning that the personage that has general technical ability in the technical field of the invention understands." first " of using in this specification and claims or " second " and similar word do not represent any order, quantity or importance, and just are used for distinguishing different parts." one " or similar words such as " one " do not represent restricted number, but there is at least one in expression." perhaps " comprise any one or all in the cited project." comprise " or " comprising " etc. similarly word mean to appear at the element of " comprising " or " comprising " front or object and contain and appear at element or object and the equivalent element thereof that " comprising " or " comprising " enumerate later, do not get rid of other elements or object." connection " or " linking to each other " etc. similarly word be not to be defined in connection physics or machinery, but can comprise electrical connection, no matter be directly or indirectly.In addition, " circuit " or " Circuits System " and " controller " etc. can comprise single component or by a plurality of active members or passive device directly or the set that indirectly links to each other, one or more integrated circuit (IC) chip for example, the function that correspondence is described to provide.
Figure 1 shows that the summary module diagram of a kind of execution mode of the energy conversion system 10 that the present invention discloses.In the illustrated embodiment, this energy conversion system 10 roughly comprises converter device 14, the first electric energy 121 that this converter device 14 is configured to obtain from energy source 12 converts the second electric energy 141 to, and this second electric energy 141 is offered load 19 and/or electrical network 16.This first electric energy 121 can be direct current energy, and for example, this direct current energy can be by producing such as devices such as photovoltaic panels; This first electric energy 121 also can be AC energy, and for example, this AC energy can be by producing such as devices such as wind turbines.In other embodiments, should be used for providing the energy source 12 of the first electric energy 121 can to include but not limited to for the distributed power generation device of any type fuel cell, storage battery, Microturbine, water turbine, tidal energy turbine etc.When the first electric energy 121 is direct current energy, the converter structure that this converter device 14 can be configured to the converter structure of single-stage or twin-stage (for example, DC-AC current transformer and AC-DC current transformer), it can convert direct current energy to the AC energy with specific voltage and frequency when running, carry with power supply network 16, and/or consume for local load 19.When the first electric energy 121 is AC energy, the converter structure that this converter device 14 also can be configured to the converter structure of single-stage or twin-stage (for example, AC-DC current transformer and DC-AC current transformer), it can carry out the map function that exchanges to exchanging when running, carry with the AC energy power supply network 16 that suitable voltage and frequency are provided, and/or consume for local load 19.
In the illustrated embodiment, this energy conversion system 10 can also comprise inverter controller 18, this inverter controller 18 can be configured to the output communication connection with this converter device 14, with measured one or more electrical parameter values of the output that is received in this converter device 14 (for example, voltage, frequency, phase place, impedance, harmonic wave, active power, and/or reactive power), these electrical quantitys can measure or calculate by the data of measuring by one or more transducer (not shown in figure 1).In some embodiments, can on connection line between converter device 14 and the electrical network 16, any selection a bit measure these electrical quantitys.Especially, in specific execution mode, the measurement of electrical quantity is carried out in the position 143 that can select to be commonly referred to as points of common connection (Point of Common Coupling, PCC).After obtaining the measured signal of telecommunication 142, in conjunction with one or more instruction or reference signal, this inverter controller 18 can be carried out one or more control algolithm or controlling mechanism, and (for example transmit control signal 182 based on execution result, the switching signal of control converter device 14 interior semiconductor switch devices) gives converter device 14, control the running of converter device 14, and then one or more electrical parameter values of converter device 14 outputs is regulated.More specifically, this inverter controller 18 can be configured to (for example carry out the first controlling mechanism, d axle control loop), to regulate the active power of converter device 14 outputs, perhaps regulate the direct voltage at converter device 14 input dc bus places.This inverter controller 18 can also be configured to carry out the second controlling mechanism (for example, q axle control loop), to regulate the reactive power of converter device 14 outputs.In specific execution mode, this first controlling mechanism and this second controlling mechanism can be carried out decoupling zero control, to realize the independent control to active power and reactive power.
Please continue to consult Fig. 1, this inverter controller 18 can comprise isolated island detection module or isolated island protection module 180, this isolated island protection module 180 can be carried out by inverter controller 18, to disconnect when being electrically connected in electrical network tripping operation or with energy conversion system 10, the islet operation situation of detected energy converting system 10, and when definite energy conversion system 10 operates in the isolated island situation really, interrupt the Power supply to load 19 and/or electrical network 16.In concrete execution mode, this isolated island protection module 180 can be presented as one section computer program, this computer program can comprise some the program command that can be carried out by computer, and this program command can be stored in the storage device of non-instantaneous (non-transitory), for reading and carrying out; This isolated island protection module 180 also can be presented as a hardware circuit, and this hardware circuit can comprise a plurality of interconnective electronic devices, and it is configured to equally carry out the isolated island measuring ability and corresponding defencive function is provided.In the illustrated embodiment, this isolated island comprises that module 180 can be the same with the second controlling mechanism as other first controlling mechanisms, is arranged on inverter controller 18 inner execution, and forms a single device.In other embodiments, this isolated island protection module 180 should also can be configured to relative inverter controller 180 and independently installs.
Please continue to consult Fig. 1, in one embodiment, isolated island protection module 180 shown in Figure 1 also is configured to produce isolated island disturbing signal and disturbance compensation signal.This isolated island disturbing signal can be according at the variable quantity of one or more measured electrical quantity of converter device 14 outputs (for example, frequency change and/or change in voltage) produce, and this isolated island disturbing signal can act in the control loop in the inverter controller 18, to change one or more command signal or the reference signal in this control loop, thereby change one or more electrical parameter values of these converter device 14 outputs, to make things convenient for the detection of islet operation situation.For example, this isolated island disturbing signal can be q axle reactive current disturbing signal, and it is used to revise the command signal of reactive current, and then changes the reactive power of output, thereby the Frequency generated that causes output changes.Yet, because the impact of the cross-couplings mechanism between the controlled loop, for example, cross-couplings impact between d axle control loop and q axle control loop, the q axle reactive current disturbing signal of injecting can cause simultaneously that the active power of converter device 14 outputs changes, this unexpected active power changes so that the frequency change of output can not reach the numerical value of expectation, thereby so that disturbance becomes effective not.For addressing this problem, in one embodiment, in the process of injecting the isolated island disturbing signal, produce simultaneously a disturbance compensation signal, and this disturbance compensation signal acted in the control loop in the current transformer control 18 in some way, to avoid or to reduce because for example active power change that caused of reactive current disturbing signal of isolated island disturbing signal as far as possible.Certainly, in other embodiments, this disturbance compensation signal also can produce and be applied in the control loop in the inverter controller 18 by specific mode, for example, this disturbance compensation signal can be the overcompensation signal, and this overcompensation signal carries out disturbance with the type of action identical with the isolated island disturbing signal to the target electrical quantity, under the effect of positive feedback, rapidly the target electrical quantity is disturbed out the normality threshold scope, to realize the detection of islet operation situation.
Figure 2 shows that the module diagram of a kind of execution mode of the photovoltaic energy converting system 20 that the present invention discloses.Although; in this embodiment; photovoltaic energy converting system 20 is used as specific example; improved island detection method or the algorithm that the present invention relates to is described in detail; but; should therefore protection scope of the present invention only be limited to the photovoltaic field; the personnel that this area had common knowledge; with the improved island detection method of this exposure or algorithm application in the energy conversion system or distributed generation system of other types; fuel cell generation for example; in wind generator system and waterpower or the tidal power system, should also be feasible.As shown in Figure 2, this photovoltaic energy converting system 20 roughly comprises photovoltaic converter device 24, the direct current energy that this photovoltaic converter device 24 is configured to be provided by photovoltaic energy source 22 converts the AC energy with appropriate voltage and frequency to, carry with power supply network 34, and/or consume for local load 36.In one embodiment, this photovoltaic energy source 420 can comprise one or more photovoltaic array, wherein each photovoltaic array comprises again a plurality of photovoltaic cells that interconnect, to be used for converting solar radiant energy to direct current energy according to photoelectric effect.
In one embodiment, this photovoltaic converter device 24 shown in Figure 2 is based on the framework of two-stage type, it comprises photovoltaic side converter 26 (also being the current transformer near photovoltaic energy source 22 sides) and net side converter 32 (also namely near the current transformer of electrical network 34 sides, being also referred to as the net side inverter).This photovoltaic side converter 26 can comprise DC-DC converter, booster type DC-DC converter for example, and it can raise by the direct voltage of photo-voltaic power supply 22 conversion outputs, and the direct voltage after will raising offers dc bus 28.This dc bus 28 can comprise one or more capacitor, maintains specific numerical value in order to the magnitude of voltage with the direct voltage of dc bus 28, thereby can control from dc bus 28 to electrical network 34 energy flow.This net side converter 32 can comprise the DC-AC current transformer, converts in order to the direct voltage with dc bus 28 places to be fit to the alternating voltage that AC network 34 is carried.Describe for convenient, photovoltaic energy converting system 20 shown in Figure 2 only shows a connecting line that is connected between net side converter 32 and the electrical network 34, to be used for exemplarily representing the measurement of single-phase current signal and voltage signal.Be understandable that, can be applied to the occasion with multiple connected mode in the photovoltaic energy converting system 20 of this exposure, include but not limited to three-phase connection system and/or heterogeneous connection system.In addition, between this net side converter 32 and electrical network 34, can further include net side filter 154.This net side filter 154 comprises one or more capacitive element and inductive element, in order to filtering from the alternating current of net side converter 32 output or the harmonic component the alternating voltage.Although in Fig. 2, do not do further signal, this photovoltaic energy converting system 20 should comprise according to the application of reality one or more other elements, include but not limited to, transformer, contactor, circuit breakers etc., these elements can be configured and be connected between this net side converter 32 and the electrical network 34.
In one embodiment, photovoltaic energy converting system 20 shown in Figure 2 further comprises photovoltaic converter control system 38, this photovoltaic converter control system 38 is by carrying out specific controlling mechanism or control algolithm, based on various feedback signals and command signal, the running of control net side converter 32.More specifically, this photovoltaic converter control system 38 comprises current transformation unit 164, and this current transformation unit 164 receives by the measured current signal 162 of current sensor 152 (being placed between net side converter 32 and load 36 or the electrical network 34).In one embodiment, this current transformation unit 164 is carried out coordinate transforms operation of static coordinate systems to the rotating coordinate system, and the current signal 162 of measuring is transformed into d axis current signal 216 and q axis current signal 218 under the rotating coordinate system.This d axis current signal 216 and q axis current signal 218 are transmitted to current regulator 208 so that electric current is regulated.
In one embodiment, this photovoltaic converter control system 38 shown in Figure 2 also comprises voltage transformation module 166, and this voltage transformation module 166 has the structure similar with current transformation unit 164, and carries out corresponding voltage transformation operation.In interchangeable execution mode, also can configure single converter unit, the coordinate transform operation that makes it carry out simultaneously voltage and current.This voltage transformation module 166 receives by the measured voltage signal 158 of voltage sensor 156 (being placed between net side converter 32 and load 36 or the electrical network 34).In one embodiment, this voltage transformation module 166 is carried out coordinate transforms operation of static coordinate systems to the rotating coordinate system, and the voltage signal 158 of measuring is transformed into d shaft voltage signals 175 and q shaft voltage signals 174 under the rotating coordinate system.About the detail of the coordinate transform operation of static coordinate system to the rotating coordinate system, the personnel that had a general knowledge for this area are known, so will it be described in detail in present embodiment.
In execution mode shown in Figure 2, the q shaft voltage signals 174 that is produced by voltage transformation module 166 is transmitted to phase-locked loop apparatus 168, with for generation of frequency signal or angular frequency signal 176.Phase-locked loop apparatus 168 generally is used for following the trail of frequency and the phase place of electrical network, and it can be carried out by traditional hardware or software service, and therefore the detailed structure about phase-locked loop apparatus 168 is not described in detail in the present embodiment yet.In the illustrated embodiment, this d shaft voltage signals 175 and frequency signal 176 are transmitted to isolated island protection module 172 (with above isolated island protection module described in conjunction with Figure 1 180 is similar).In one embodiment, this d shaft voltage signals 175 and frequency signal 176 are two kinds of reflection output electrical quantity, and it is used for especially assessing photovoltaic energy converting system 20 and whether operates in island state.For example, when the electrical quantity of assessing surpasses default normal range (NR) threshold value when (for example, surpass upper limit threshold, perhaps be lower than lower threshold), think that then this photovoltaic energy converting system 20 has been in the islet operation state.In other embodiments, except frequency signal and voltage signal, the parameter signal of other types, phase place for example, impedance, harmonic waves etc. also can be used to separately or combine estimate this photovoltaic energy converting system 20 and whether operate in island state.In one embodiment, when this frequency signal 176 and this d shaft voltage signals 175 are judged as when not violating default islet operation rule, also be, this frequency signal 176 and this d shaft voltage signals 175 are within the default normality threshold scope, and this isolated island protection module 172 can be configured to produce isolated island disturbing signal 178 and disturbance compensation signal 184 according to the combination of this frequency signal 176 or this d shaft voltage signals 175 or these two kinds of signals.In case when judging photovoltaic energy converting system 20 and operating in island state, can start the island protect function, load 36 and/or electrical network 34 is isolated with photovoltaic energy converting system 20.
In one embodiment, isolated island disturbing signal 178 and the disturbance compensation signal 184 of these isolated island protection module 172 generations are applied in the first controlling mechanism 185 or the second controlling mechanism 187.More specifically, this first controlling mechanism 185 comprises d axle control loop, and this second controlling mechanism 187 comprises q axle control loop.This d axle control loop 185 comprises direct current voltage regulator 194, the direct voltage command signal 192 that it is configured to receive the direct voltage feedback signal 188 that measures by direct current voltage sensor 186 and represents the direct voltage that is desirably in the acquisition of dc bus 28 places.This direct current voltage regulator 194 produces d shaft current command signal 196 according to this direct voltage feedback signal 188 and this direct voltage command signal 192.This q axle control loop 187 comprises voltage-idle adjuster 198, it is configured to receive representative in idle command signal 204 and the idle feedback signal 202 of the reactive power of the desired acquisition of net side converter 32 outputs, and the signal that receives regulated, with generation q shaft current command signal 206.Idle feedback signal 202 can calculate according to current signal 162 and the voltage signal 158 that above-mentioned measurement obtains referred in this.
In execution mode shown in Figure 2, this first control loop 185 be connected the second control loop 187 and be connected with current regulator 208, this current regulator 208 is configured to receive the d shaft current command signal 196 that direct current voltage regulator 194 provides, the q shaft current command signal 206 that voltage-idle adjuster 198 provides, and current transformation unit 164 the d shaft current feedback signal 216 and the q shaft current feedback signal 218 that provide.This current regulator 208 carries out electric current and regulates according to the d axle and q shaft current feedback signal and the command signal that receive, to produce d shaft voltage command signal 212 and q shaft voltage command signal 214.This d shaft voltage command signal 212 and q shaft voltage command signal 214 are provided for coordinate transform and modulating unit 138, the frequency signal 176 that provides according to phase-locked loop apparatus 168, this coordinate transform and modulating unit 138 rotate back to voltage signal under the rest frame with the d shaft voltage command signal 212 that receives and q shaft voltage command signal 214 from the d-q reference frame, and the signal after the use conversion is modulated carrier signal, to produce the control signal 182 for net side converter 32.In order to simplify, Fig. 2 uses single module 138 to show coordinate transform function and modulation function, in other embodiments, can use two modules to realize respectively this two functions.Below will describe isolated island protection module 172 in detail and how produce isolated island disturbing signal 178 and disturbance compensation signal 184, and how this isolated island disturbing signal 178 and disturbance compensation signal 184 will be applied in control loop 185 and 187.
Fig. 3 to Figure 10 shows several execution modes of isolated island protection module 172 shown in Figure 2, wherein, the isolated island disturbing signal 178 that this isolated island protection module 172 produces is applied in q axle control loop or the idle control loop 187, and this disturbance compensation signal 184 is applied into elimination or alleviates owing to injecting the 178 caused negative effects of isolated island disturbing signal.
Figure 3 shows that the detailed module diagram of a kind of execution mode of isolated island protection module 172 shown in Figure 2.In the illustrated embodiment, this isolated island protection module 172 comprises frequency change detecting unit 222 and disturbance generation unit 226.This frequency change detecting unit 222 is connected with this phase-locked loop apparatus 168, the frequency signal 176 that is produced to receive this phase-locked loop apparatus 168.In one embodiment, this frequency variation unit 222 is configured to judge whether the frequency signal 176 of this reception departs from normal frequency values (for example, 60Hz or 50Hz).More specifically, this frequency change detecting unit 222 can be compared this frequency signal 176 and normal frequency values, and draws frequency departure signal 224.In one embodiment, this frequency departure signal 224 is provided for disturbance generation unit 226, with generation current disturbing signal 228.
In one embodiment, this current disturbing signal 228 comprises q shaft current disturbing signal 228, and this q shaft current disturbing signal 228 can be by producing the suitable gain of frequency departure signal function that is provided by frequency change detecting unit 222.This q shaft current disturbing signal 228 is applied in the q axle control loop 187, to revise q shaft current command signal 238.In execution mode shown in Figure 3, this q shaft current disturbing signal 228 is carried out amplitude limitation through the first amplitude limit unit 232.Then the q shaft current disturbing signal 228 of this restriction is provided for summator 236, revising q shaft current command signal 238, and obtain revising or disturbance after q shaft current command signal 242.In another execution mode, also can revise or disturbance q shaft current command signal 238 with unrestriced q shaft current disturbing signal 228.The q shaft current command signal 242 of this modification is transmitted to current regulator 208 after being carried out amplitude limitation by the second amplitude limit unit 244, regulates to carry out electric current.In interchangeable execution mode, the q shaft current command signal 242 of this modification also can directly be given current regulator 208 and be carried out the electric current adjusting, and produces d shaft voltage command signal 212 and q shaft voltage command signal 214.
Please continue to consult Fig. 3, in one embodiment, this isolated island protection module 172 further comprises disturbance compensation unit 248, with for generation of disturbance compensation signal 252.This disturbance compensation signal 252 is used for compensation owing to introducing q shaft current disturbing signal 228 or 234, the unexpected variation that occurs at d axle control loop 185.Do not exist under disturbing signal or the steady state situations, the active power of net side converter 32 outputs and reactive power can be passed through following equation expression:
P Inv=1.5 (V dI d+ V qI q) formula (1),
Q Inv=1.5 (V qI d-V dI q) formula (2),
Wherein, in formula (1) and formula (2), V dAnd V qBe respectively d shaft voltage component and the q shaft voltage component of output voltage under the d-q rotating coordinate system, I dAnd I qBe respectively d shaft current component and the q shaft current component of output current under the d-q rotating coordinate system, V InvAnd Q InvBe respectively active power and the reactive power of 32 outputs of net side converter.According to formula (2) can, can cause that at the basis of q shaft current command signal 238 little current disturbing Δ I of stack the reactive power of net side converter 32 outputs changes.In addition, reactive power also can be expressed by following formula (3):
Q inv = V inv 2 ( 1 ωL - ωC ) Formula (3),
Wherein, V InvBe the output voltage of net side converter 32, ω is the output frequency of net side converter 32, and L is connected inductance value and the capacitance of the local load that is connected with net side converter 32 with C.According to formula (3), the variation of reactive power can cause that the output of net side converter 32 produces frequency change Δ ω, this frequency change Δ ω further is used for generation current disturbance Δ I, this current disturbing has the symbol identical with frequency change, disturbance is operated in the mode of positive feedback, thereby the accumulation that the frequency change of each time is continued in one direction, the final so that frequency of output is disturbed out outside the normal frequency range.In one embodiment, this normal scope is configured to have a higher limit and a lower limit.In interchangeable execution mode, for some other electrical quantity, this normal scope can only have a higher limit or only have a lower limit.In normal operation; when electrical network 34 is connected with net side converter 32; substantially remain unchanged or the fluctuation of Xiao Fu is only arranged but can not trigger the action that island protect is correlated with frequency that will output because the frequency of electrical network is enough stable; therefore the caused frequency disturbance of isolated island disturbing signal can be because the regulating action of electrical network; and can not continue in one direction accumulation, thereby do not affect normal electric energy output.Yet, lose when being electrically connected when electrical network tripping operation or with photovoltaic energy converting system 20, electrical network loses the control to photovoltaic energy conversion system 20 output frequencies, therefore, the frequency change Δ ω that causes by Injection Current disturbance Δ I can continue accumulation, thereby output frequency shifts out outside the normal frequency range the most at last.In this case, can detect the islet operation situation, and can start corresponding operation, for example, unlatching is connected to the switch between net side converter device 32 and the local load 36, local load 36 is kept apart with net side converter device 32, perhaps net side converter device 32 is closed, to cut off the Power supply to local load 36.
By formula (3), when the action current disturbing signal, more satisfactory situation is that the voltage of keeping net side converter 32 outputs remains unchanged, so that reactive power is only relevant with frequency.Yet when the unexpected variable quantity that the isolated island disturbing signal that acts on is not caused was done any compensation, usually things turn out contrary to one's wishes.More specifically, when q shaft current disturbing signal 228 or 234 was applied q axle control loop, the active power of these net side converter 32 outputs can be expressed as follows:
P Inv_dis=P Inv+ Δ P formula (4),
Δ P=1.5 (I q+ Δ I q) Δ V qFormula (5),
Wherein, in formula (4) and formula (5), Δ I qBe q shaft current disturbing signal, Δ V qBe effect q shaft current disturbing signal Δ I qCaused q shaft voltage changes, P Inv_disBe the active power of net side converter 32 outputs after disturbance, Δ P is effect q shaft current disturbing signal Δ I qCaused active power changes.Can find out from formula (4) and (5), introduce q shaft current disturbing signal, the reactive power of output is changed, can cause that simultaneously the active power of not expecting changes.Because active power also can be expressed as follows:
P inv = V inv 2 R Formula (6),
Wherein, in formula (6), V InvBe the output voltage of net side converter 32 outputs, R is the resistance value of the local load that links to each other with net side converter 32 outputs.In order to solve above-mentioned unexpected active power variation issue, in one embodiment, being changed by the q shaft current disturbing signal 228 caused active power of injecting can be by voltage compensation signal of effect, so that final q shaft voltage changes delta V qVanishing.Therefore, the output frequency of these net side converter 32 outputs can more effectively pass through to introduce the change of q shaft current disturbing signal, and is not subjected to the impact of unexpected active power.
This disturbance compensation signal 252 that produces by this disturbance compensation unit 248 in one embodiment comprises q shaft voltage compensating signal 252.In one embodiment, this q shaft voltage compensating signal 252 carries out amplitude limitation by clipping element 254, and the voltage signal 256 of this process amplitude limitation is transmitted to summator 258.This summator 258 is with q shaft voltage command signal 214 and 256 additions of q shaft voltage compensating signal, to produce the q shaft voltage command signal 262 after compensating.
Please further consult Fig. 4, it is depicted as the module diagram of a kind of execution mode of the element that comprises at least dynamic compensation unit 248 shown in Figure 3 and current regulator 208.This current regulator 208 comprises d shaft current adjuster 227, it is configured to regulate according to d shaft current deviation signal 225, to produce d shaft voltage command signal 229, wherein, this d shaft current deviation signal 225 is obtained by d shaft current command signal 196 and d shaft current feedback signal 216 are subtracted each other by summator 223.This d shaft voltage command signal 229 is transmitted to summator 230, and summed element 230 is used for subtracting each other with the voltage signal 231 that is calculated by q shaft current feedback signal 218 and impedance 235 at least, to produce d shaft voltage command signal 233.This current regulator 208 further comprises q shaft current adjuster, it is configured to regulate according to q shaft current deviation signal 239, to produce q shaft voltage command signal 243, wherein, this q shaft current deviation signal 239 is obtained by the combination of q shaft current command signal 206 and q shaft current disturbing signal 228 or 234 is subtracted each other with q shaft current feedback signal 218 by summator 237.This q shaft voltage command signal 243 is transmitted to summator 258, this summator 258 receives the voltage signal 249 that is calculated by d shaft current feedback signal 216 and impedance 247 at least, also receive q shaft voltage compensating signal 259, and the signal summation to receiving, the q shaft voltage command signal 251 after being compensated.
In execution mode shown in Figure 4, this dynamic compensation unit 248 comprises q axle compensated regulator 253 and the unit 257 of negating.This q axle compensated regulator 253 can be by q shaft current disturbing signal 228 or the gain of 234 effects to receiving, to obtain q shaft voltage compensating signal 255.This q shaft voltage compensating signal 255 is negated after unit 257 negates, and the voltage compensation signal 259 after it is negated is used to being compensated by q shaft current the disturbing signal 228 or 234 caused unexpected voltage signals that act at q axle control loop 187.In one embodiment, be zero substantially after the voltage compensation signal 259 after this is negated and this unexpected voltage signal addition.Also namely, even if by voltage compensation mechanism so that the active power of net side converter 32 outputs in the situation that the effect of q shaft current disturbing signal is arranged, still substantially remain unchanged.Therefore, the target electrical quantity of these net side converter 32 outputs, for example, frequency can only be correlated with q shaft current disturbing signal 228 or 234.When electrical network is lost or during being electrically connected of disengaging and photovoltaic energy converting system 20, the frequency of these net side converter 32 outputs can in the official hour scope (for example, two seconds), be shifted out outside the normal frequency range more rapidly.Then, can detect these photovoltaic energy converting system 20 runnings in the isolated island situation, and correspondingly protect action, for example, net side converter 32 be closed, the stop supplies electric energy is given local load 19.
Please further consult Fig. 5, it is depicted as the module diagram of the another kind of execution mode of the element that comprises at least dynamic compensation unit 248 shown in Figure 3 and current regulator 208.Element shown in Figure 5 is substantially similar with element shown in Figure 4.Especially, in Fig. 5, this dynamic compensation unit 248 is configured to have the overcompensation function, perhaps is called dynamic overcompensation unit.This dynamic overcompensation unit 248 comprises q axle compensated regulator 253 and gain unit 261.This q axle compensated regulator 253 produces voltage compensation signal 255 according to q shaft current disturbing signal 228 or 234.This gain unit 261 is connected with this q axle compensated regulator 253, and K gives this voltage compensation signal 255 with the effect gain coefficient, to produce q shaft voltage overcompensation signal 263.In one embodiment, this gain coefficient K can be regulated according to the situation of reality, so that 263 overcompensation degree to the target electrical quantity that can provide of q shaft voltage overcompensation signal to be provided.By voltage overcompensation mechanism, the target electrical quantity of net side converter 32 outputs, for example output frequency can be moved out of outside the normal frequency range more rapidly, therefore, can shorten the detection time of isolated island situation.In other embodiments, the element that Fig. 4 and this dynamic compensation unit shown in Figure 5 or this dynamic overcompensation unit 248 can also comprise one or more other functions, for example, one or more filter element, be applied before paired voltage instruction compensates at compensating signal 259 or overcompensation signal 263, carry out filtering operation.
Figure 6 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module 172 shown in Figure 2, wherein, this execution mode is also adjusted function to adjust the amplitude of isolated island disturbing signal by increasing dynamic gain.More specifically, in one embodiment, this isolated island protection module 172 further comprises frequency change rate detecting unit 298 and dynamic gain adjustment unit 304.This frequency change rate detecting unit 298 is connected with this frequency change detecting unit 222, with receive frequency deviation signal 224, and according to frequency departure signal 224 generation frequency change rate signals 302.This dynamic gain adjustment unit 304 is configured to be connected with this frequency change rate detecting unit 298, with receive frequency rate of change signal 302, and produces the gain signal 306 of following these frequency change rate signal 302 dynamic changes.In the process that detects the isolated island situation, early stage frequency (for example, electrical network breaks away from the frequency that connects the rear incipient stage) may be with less rate of change in change, therefore, in order to accelerate the movement of frequency, to carry out easily and fast the detection of isolated island situation, increasing disturbance quantity that can be suitable is to reach this purpose.In this case, can adjust gain signal 306, and it is applied to current disturbing generation unit 226 has current disturbing signal 228 than amplitude with generation.Under another situation, along with the effect of current disturbing signal 228, and under positive feedback effect, in the middle and later periods of disturbance, the frequency of these net side converter 32 outputs can have larger rate of change.In order to keep Systems balanth, this dynamic gain adjustment unit 304 can be adjusted to less numerical value with gain signal 306 according to this larger frequency change rate, with the current disturbing signal 228 that suitably reduces to be produced.
Figure 7 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module 172 shown in Figure 2.In the illustrated embodiment, to carry out the isolated island condition detection different from use q shaft current disturbing signal mentioned above, this isolated island protection module 172 comprises idle disturbance generation unit 308, and this is idle, and disturbance generation unit 308 is configured to produce idle disturbing signal 312 according to frequency variation signal 224.Disturbing signal 312 that this is idle or the idle disturbing signal 314 of carrying out after the amplitude limitation through the first amplitude limit unit 232 are transmitted to summator 316, this summator 316 should idle disturbing signal 312 or 314 and 204 additions of reactive power command signal, so that idle command signal 204 is made amendment or disturbance, obtain amended idle command signal 318.The amended idle command signal 318 of this process is transmitted to voltage-idle adjuster 198, and it is regulated according to idle feedback signal 202 (referring to Fig. 2) and voltage feedback signal etc., produces q shaft current command signal 322.This q shaft current command signal 322 is after the second clipping element 244 carries out amplitude limitation, and the q shaft current command signal 324 after the restriction of its generation is transmitted to current regulator 208 and regulates.In interchangeable execution mode, also can directly send the q shaft current command signal 322 without amplitude limitation to current regulator 208 and regulate.Further, in the illustrated embodiment, this dynamic compensation unit 248 uses this idle disturbing signal 312 or 314 to produce voltage compensation signal 252.The q shaft voltage command signal 214 that this voltage compensation signal 252 is used to that current regulator 208 is provided is made amendment or is compensated, to offset or to reduce owing to introducing idle disturbing signals 312 or 314 and change in the unexpected active power that the d axle produces at q axle control loop 187.The structure of dynamic compensation unit 248 shown in Figure 7 and Fig. 4 and dynamic compensation unit shown in Figure 5 are similar, also can be configured to equally have dynamic overcompensation function.
Figure 8 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module 172 shown in Figure 2, wherein, frequency change rate detecting unit 298 is used to detect the rate of change of frequency.This isolated island protection module 172 also comprises dynamic gain adjustment unit 304, and it is used to produce gain signal 306 according to detected frequency change rate.Similarly, this gain signal 306 is applied this idle disturbance generation unit 308, with the amplitude of the idle disturbing signal 312 of dynamic adjustment.
Figure 9 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module 172 shown in Figure 2.This isolated island protection module 172 comprises compound disturbing signal generation unit 326, with for generation of a plurality of disturbing signals.In one embodiment, this compound disturbing signal generation unit 326 produces q shaft current disturbing signal 328 and idle disturbing signal 332 according to frequency change detecting unit 222 detected frequency departure signals 224.This q shaft current disturbing signal 328 and this idle disturbing signal 332 can be carried out corresponding amplitude limitation through the first amplitude limit unit 334, and q shaft current disturbing signal 336 and idle disturbing signal 338 after the restriction are transmitted to respectively the first summator 236 and the second summator 316, to revise respectively or disturbance q shaft current command signal 344 and idle command signal 204.Further, this isolated island protection module 172 also comprises dynamic compensation unit 248, its according to this q shaft current disturbing signal 328 or 336 and idle disturbing signal 332 or 338 produce q axle disturbance compensation signals 252.This q axle disturbance compensation signal 252 is after the 3rd clipping element 254 carries out amplitude limitation, q axle disturbance compensation signal 256 after its restriction is transmitted to summator 258, revising or compensation q shaft voltage instruction 214, thereby offset or reduce owing to introducing q shaft current disturbing signals 328 or 336 and idle disturbing signal 332 or 338 and change in the unexpected active power that the d axle produces at q axle control loop 187.
Figure 10 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module 172 shown in Figure 2, wherein, this isolated island protection module 172 also comprises dynamic gain adjustment mechanism.More specifically, the gain signal 306 that produces by dynamic gain adjustment unit 304 can have larger numerical value in the disturbing signal mechanism in early days, so that compound disturbing signal generation unit 326 can produce q shaft current disturbing signal 328 and the idle disturbing signal 332 of bigger numerical according to this gain signal 306, can be with the target electrical quantity of output with this, for example, the frequency of net side converter 32 outputs is disturbed out normal frequency range fast, detects to make things convenient for isolated island.Further, in the disturbing signal mechanism in mid-term or later stage, can the gain signal that produce be adjusted to by dynamic gain adjustment unit 304 and have less numerical value, so that so that q shaft current disturbing signal 328 and idle disturbing signal 332 that compound disturbing signal generation unit 326 produces than fractional value according to this gain signal 306, to keep system stability.
Figure 11 to Figure 16 shows other several execution modes of isolated island protection module 172 shown in Figure 2, wherein, the isolated island disturbing signal 178 that this isolated island protection module 172 produces is applied in d axle control loop or the real power control loop 185, and this disturbance compensation signal 184 is applied into elimination or alleviates because in d axle control loop 185 injection isolated island disturbing signals 178 and in the caused negative effect of q axle control loop.
Figure 11 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module 172 shown in Figure 2.In the illustrated embodiment, this isolated island protection module 172 comprises change in voltage detecting unit 352 and disturbance generation unit 356.This change in voltage detecting unit 352 is connected with voltage transformation module 166, carries out the d shaft voltage feedback signal 175 that coordinate transform produces to receive by this voltage transformation module 166.This change in voltage detecting unit 352 is configured to judge whether the d shaft voltage feedback signal 175 of this reception changes, and for example, whether departs from normal magnitude of voltage.More specifically, the d shaft voltage feedback signal 175 that this change in voltage detecting unit 352 will receive compares with normal magnitude of voltage, and obtains voltage deviation signal 354.This voltage deviation signal 354 is provided for disturbance generation unit 356, with for generation of disturbing signal.In other embodiments, also can whether change by the frequency that detects net side converter 32 outputs, and produce disturbing signal according to frequency change, for example, the frequency departure signal 224 that produces according to Fig. 3 and the described frequency change detecting unit 222 of Fig. 6 to Figure 10 produces disturbing signal.In some other execution modes, the frequency departure signal 224 that the voltage deviation signal 354 that also can be simultaneously provides in conjunction with change in voltage detecting unit 352 and frequency change detecting unit 222 provide produces disturbing signal.
Please continue to consult Figure 11, in one embodiment, the disturbing signal that this disturbance generation unit 356 produces comprises d shaft current disturbing signal 362.This d shaft current disturbing signal 362 can obtain by suitable gain of voltage deviation signal 354 effects that change in voltage detecting unit 352 is provided.Be appreciated that this d shaft current disturbing signal 362 mainly is used to d axle control loop 185 is carried out disturbance.Shown in above-mentioned formula (1), d shaft current command signal 196 is made a slight current disturbing amount Δ I, can cause that the active power of net side converter 32 outputs changes.Further according to formula (6), the active power variation can force the voltage of net side converter 32 outputs to change.And this voltage variety Δ V can further be used for generation current disturbance Δ I, and the symbol of the symbol of this current disturbing and change in voltage is consistent.Therefore, by this positive feedback mechanism, so that the variation of voltage can be accumulated in same direction, and finally disturbed out outside the normal voltage range value.In normal operation, when electrical network 34 keeps normal electrical to be connected with net side converter 32, because the voltage of electrical network 34 is more stable, its enough with the voltage clamp of net side converter 32 outputs within normal voltage range value, so disturbing signal can't exert an influence to the voltage of output.And when electrical network 34 loses with being electrically connected of net side converter 32, electrical network 34 has also lost the control to output voltage, and therefore, the disturbance quantity that each time applies is under the effect of positive feedback, can continue accumulation, and output voltage is disturbed out outside the normal voltage range the most at last.In this case; when the output voltage of judging net side converter 32 is disturbed out outside the normal voltage really; also be that 20 runnings of photovoltaic energy converting system are when island state; can start corresponding protection action; for example that local load 19 is isolated with net side converter 32; cut off Power supply, perhaps directly close net side converter 32.
In execution mode shown in Figure 11, d shaft current disturbing signal 362 is carried out amplitude limitation by the first amplitude limit unit 364, and the d shaft current disturbing signal 362 after the restriction is transmitted to summator 368, to revise or disturbance d shaft current command signal 196.In another execution mode, also can directly use without the d shaft current disturbing signal 362 of amplitude limitation and revise d shaft current command signal 196.Amended d shaft current command signal 372 can carried out amplitude limitation through the second amplitude limit unit 374, and the d shaft current command signal 376 after the restriction is transmitted to current regulator 208 and regulates.In the execution mode of replacing, also can directly directly send this amended d shaft current command signal 372 to current regulator 208 and regulate, and produce d shaft voltage command signal 212 and q shaft voltage command signal 214.
Please further consult Figure 11, in one embodiment, this isolated island protection module 172 also comprises disturbance compensation unit 248, and this disturbance compensation unit 248 is used for producing disturbance compensation signal 382 according to d shaft current disturbing signal 362 or 366.This disturbance compensation signal 382 is used to compensation because in d axle control loop 185 effect disturbing signals, for example d shaft current disturbing signal 362 or 366 and change in the unexpected reactive power that the q axle causes.
More specifically, in one embodiment, this disturbance compensation signal 382 that produces by this disturbance compensation unit 248 comprises d shaft voltage compensating signal.After this d shaft voltage compensating signal 382 can carry out amplitude limitation by the 3rd amplitude limit unit 384 first, d shaft voltage compensating signal 386 after will limiting again sends summator 388 to, then by this summator 388 with this d shaft voltage compensating signal 386 and 212 additions of d shaft voltage command signal, to produce the d shaft voltage command signal 392 after the compensation.After this voltage compensation, can eliminate or reduce the above-mentioned unexpected reactive power that causes at the q axle of mentioning and change.
Figure 12 shows that a kind of detailed module diagram of execution mode of the isolated island protection module 172 of elements such as comprising at least current regulator shown in Figure 11 208 and dynamic compensation unit 248.Therefore the subelement of Figure 12 and subelement shown in Figure 4 are similar, about this omission that is described in of these likes.In Figure 12, d shaft current disturbing signal 362 or 366 is imported into summator 223, so that d shaft current command signal 196 is carried out disturbance, and produces the d shaft current deviation signal 225 of disturbance.This d shaft current deviation signal 225 obtains d shaft voltage command signal 227 after regulating through d shaft current adjuster 227.Further, should comprise d axle compensated regulator 265 by disturbance compensation unit 248, this d axle compensated regulator 265 receives this d shaft current disturbing signal 362 or 366, and produces accordingly voltage compensation signal 271.This voltage compensation signal 271 is transmitted to summator 229, then by summator 229 with this voltage compensation signal 271 and these d shaft voltage command signal 227 additions, with the d shaft voltage command signal 233 that is compensated.By this compensation mechanism, owing to the variation of introducing the reactive power that the active current disturbing signal causes can be eliminated or reduce, and under the situation that reactive power remains unchanged substantially, impel the voltage of net side converter 32 outputs or frequency outside normal voltage or frequency range value, to move.Therefore; when electrical network 34 loses with being electrically connected of net side converter 32; can pass through the active current perturbation action; frequency or voltage are disturbed out outside the normal value range; and detecting after photovoltaic energy converting system 20 is operated in island state; start corresponding protection action, guarantee security of system.In one embodiment; can detect simultaneously voltage or the frequency of net side converter 32 outputs; any one in voltage or the frequency is detected is at first disturbed out outside its corresponding normal range (NR); for example; output voltage is detected the specific output frequency and breaks away from first its normal value range; namely think to have detected the isolated island situation, and start corresponding protection action.
At least the elements such as current regulator shown in Figure 11 208 and dynamic compensation unit 248 that are included as shown in Figure 13 are at the detailed module diagram of the another kind of execution mode of interior isolated island protection module 172.In the illustrated embodiment, this dynamic compensation unit 248 also is configured to have dynamic overcompensation function, therefore also can be known as dynamic overcompensation unit.Especially, this dynamic overcompensation unit 248 comprises d axle overcompensation adjuster 267, and this d axle overcompensation adjuster 267 produces d axle overcompensation voltage signal 275 according to d shaft current disturbing signal 362 or 366.By this voltage overcompensation mechanism, not only can eliminate the unexpected idle variation that causes at the q axle owing to injecting disturbing signals at d axle control loop 185, and can the mode identical with d axle disturbing signal impel the target electrical quantity, the for example variation of voltage or frequency is to disturb out more quickly it outside normal voltage or the frequency range.
Figure 14 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module 172 shown in Figure 2.This isolated island protection module 172 shown in Figure 14 comprises voltage change ratio detecting unit 404 and dynamic gain adjustment unit 408.This voltage change ratio detecting unit 404 is connected with this change in voltage detecting unit 352, with receiver voltage deviation signal 354, and produces accordingly voltage change ratio signal 406.This dynamic gain adjustment unit 408 is connected with this voltage change ratio detecting unit 404, receiving this voltage change ratio signal 406, and produces accordingly the gain signal 412 of following these voltage change ratio signal 406 dynamic changes.For example, can be adjusted at early stage or this gain signal 412 of initial stage of disturbance and to have relatively large numerical value, so that current disturbing generation unit 356 can produce relatively large disturbing signal, accelerate the disturbance to the target electrical quantity; Along with further carrying out of disturbance, in stage middle and later periods, this gain signal 412 can be adjusted to the numerical value with less, to reduce the amplitude of the disturbing signal that current disturbing generation unit 356 produced, keeps system stability.
Figure 15 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module 172 shown in Figure 2.In execution mode shown in Figure 15, this isolated island protection module 172 comprises voltage disturbance generation unit 414, and its voltage change signal 354 that is configured to detect according to change in voltage detecting unit 352 produces direct voltage disturbing signal 416.With above modification d shaft voltage command signal 196 described in conjunction with Figure 11 is similar, this direct voltage disturbing signal 416 is used to revise direct voltage command signal 192, with the active power of change net side converter 32 outputs, and impel the voltage of output or Frequency generated to change.Certainly, also can carry out amplitude limit by 418 pairs of these direct voltage disturbing signals 416 in the first amplitude limit unit, and make amendment or disturbance with 422 pairs of direct voltage command signals 192 of the disturbing signal behind the amplitude limit.Further, in one embodiment, this direct voltage disturbing signal 416 or 422 is fed to dynamic compensation unit 248, and is used for producing d shaft voltage compensating signal 382 by this dynamic compensation unit 248.Especially, this d shaft voltage compensating signal 382 is after amplitude limitation is made in the 3rd amplitude limit unit 384, d shaft voltage compensating signal 386 after its restriction is transmitted to summator 388, d shaft voltage command signal 212 combinations that this summator 388 produces this d axle compensating signal 386 and current regulator 208 are with d shaft voltage command signal 392 that obtain revising or compensation.By d shaft voltage command signal 392 is compensated, can eliminate or reduce because injection direct voltage disturbing signal 416 or 422 caused unexpected reactive powers change, thereby so that the disturbance of direct voltage disturbing signal 414 or 422 be more effective.
Figure 16 shows that the detailed module diagram of the another kind of execution mode of isolated island protection module 172 shown in Figure 2.Fig. 6,8,10,14 described execution modes are similar with above being combined, and this isolated island protection module 172 comprises that also dynamic gain adjusts mechanism.Adjust mechanism by this dynamic gain, can act on dynamic gain signal 412 and produce the adjustable direct voltage disturbing signal 416 of amplitude, also can keep system stability simultaneously so that this photovoltaic energy converting system 20 can detect the isolated island situation rapidly.
Figure 17 shows that the module diagram of the another kind of execution mode of the photovoltaic energy converting system 40 that disposes improved isolated island protection module 172.In the illustrated embodiment, the photovoltaic converter device 14 of this photovoltaic energy converting system 40 is based on the framework of single stage type.More specifically, this photovoltaic converter device 14 comprises net side converter 148, and it is configured to direct direct voltage with dc bus 146 places and converts the alternating voltage with appropriate frequency and amplitude to, with feed-in electrical network 16.This photovoltaic energy converting system 40 further comprises photovoltaic control device of converter 18, and this photovoltaic control device of converter 18 is connected with this photovoltaic converter device 14, is used for transmitting control signal 182 to this photovoltaic converter device 14, to control its operation.This photovoltaic control device of converter 18 is similar with photovoltaic control device of converter 18 shown in Figure 2.Equally, the element that function is similar, for example current transformation unit 164, voltage transformation module 166, phase-locked loop apparatus 168, current regulator 208, voltage-idle adjuster 198, the detail of the element such as coordinate transform and modulating unit 138 or module is not shown in this omission.
In execution mode shown in Figure 17, the described execution mode of Fig. 2 to Figure 16 is similar with above being combined, this photovoltaic control device of converter 18 also is configured to carry out the ability of isolated island testing mechanism or algorithm, especially, this photovoltaic control device of converter 18 can be carried out for example disturbance compensation mechanism or algorithm, perhaps disturbance overcompensation mechanism or algorithm, and dynamic gain adjustment mechanism or algorithm.Also namely, in the process of injecting the isolated island disturbing signal, simultaneously by producing and effect disturbance compensation signal, to eliminate or to reduce because the caused unexpected variation of isolated island disturbing signal or the counter productive of injecting.In one embodiment, the photovoltaic energy converting system 40 of this single stage type can also be carried out maximum power point tracking (Maximum Power Point Tracking, MPPT) mechanism or algorithm.Refer to a kind of like this controlling mechanism or algorithm at this so-called " maximum power point tracking mechanism or algorithm ", it can be carried out by photovoltaic control device of converter 18, even if under the situation with the irradiation energy change guaranteeing to be received in photovoltaic energy source 12, also can extract from photovoltaic energy source 12 maximum photovoltaic power.
See also Figure 17, this photovoltaic energy converting system 40 comprises maximum power point tracking device 26, this maximum power point tracking device 26 receives respectively by current sensor 28 and voltage sensor 32 detected photovoltaic current signal 112 and photovoltaic voltage signals 114, wherein, this current sensor 28 and photovoltaic transducer 32 are placed between this photovoltaic energy source 12 and this dc bus 146.This maximum power point tracking device 26 further is configured to according to the photovoltaic current signal 112 of this reception and photovoltaic voltage signal 114, carry out the maximum power point tracking algorithm, for example, disturbance observation method or conductance increment method are to search out the best operating point in this photovoltaic energy source 12.In one embodiment, this maximum power point tracking device 26 provides direct voltage reference signal 192 according to this photovoltaic current signal 112 and photovoltaic voltage signal 114.Because the voltage at dc bus 146 places and the output voltage in photovoltaic energy source 12 are basic identical, therefore the voltage by control dc bus 146 places can search out maximum power point.These direct voltage reference signal 192 representatives are desirably in the direct voltage that these dc bus 146 places obtain, it is transmitted to direct current voltage regulator 194, and be used for according to by the measured direct voltage feedback signal 188 of direct current voltage sensor 186 by direct current voltage regulator 194, produce d shaft current command signal 196, this d shaft current command signal is also regulated to further sending current regulator 208 to.
Please further consult Figure 17, the frequency signal 176 that is provided by phase-locked loop apparatus 168 and the d shaft voltage signals 175 that is provided by voltage transformation module 166 also can be provided this isolated island protection module 172, according to the input frequency change and the change in voltage that receive, and producing isolated island disturbing signal 178 and disturbance compensation signal 184 according to the frequency change that detects and/or change in voltage.In one embodiment, this isolated island disturbing signal is applied into modification or disturbance direct voltage reference signal 192.In one embodiment, the direct voltage reference signal 192 that this maximum power point tracking device 26 provides can be revised by isolated island disturbing signal 178, to change input power and power output, thereby break the poised state between 148 outputs of net side converter and the load (scheming not shown), so that more effectively detect the islet operation situation.Similarly, this disturbance compensation signal 184 is applied into elimination or reduces owing to introducing the unexpected variation that isolated island disturbing signal 178 produces.
Figure 18 shows that islet operation detects or the flow chart of a kind of execution mode of guard method 4000; carry out that this islet operation detects or guard method 4000 can conveniently detect come in and go out Fig. 2 and photovoltaic energy converting system 20 and 40 shown in Figure 17 and whether operates in the isolated island situation, and after detecting the isolated island situation, can start corresponding protection action.In the following detailed description, each step of the method flow chart 4000 mainly is described in conjunction with this energy conversion system 20, the method flow chart 4000 can be programmed for program command or computer software, and is kept on the storage medium that can be read by computer or processor.When this program command is carried out by computer or processor, can realize each step shown in flow chart.The medium that is appreciated that computer-readable can comprise volatibility with non-volatile, with any method or technology realize movably and non-movably medium.More specifically, the medium of computer-readable includes but not limited to random access storage device, read-only memory, electrically erasable read-only memory, flash memories, the perhaps memory of other technologies, compact disc read-only memory, the digitlization disk storage, perhaps other forms of optical memory, cassette, tape, magnetic disc, the storage medium that can be used to the predetermined information that stored energy accessed by instruction execution system of perhaps other forms of magnetic storage, and any other form.
In one embodiment, the method 4000 can begin to carry out from step 4002.In step 4002, obtain one or more electrical quantity of energy conversion system 20 outputs.For example, obtain net side converter 32 output frequencies by phase-locked loop apparatus 168, obtain the d axle component of net side converter 32 output voltages by voltage transformation module 166.
In step 4004, whether at least one electrical quantity that the method 4000 continues this acquisition of detection changes.For example, can detect frequency by frequency change detecting unit 222 and whether change, can also detect voltage by change in voltage detecting unit 352 and whether change.
In step 4006, as an optional step.Adjust mechanism generation isolated island disturbing signal by carrying out dynamic gain.Step 4006 can comprise substep 4003 and 4005, to determine corresponding gain signal by the rate of change of determining electrical quantity.For example, in substep 4003, further detect voltage change ratio signal and frequency change rate signal by detected voltage change signal or frequency variation signal.In substep 4005, according to this voltage change ratio signal and or frequency change rate signal generation gain signal.More specifically, when frequency or change in voltage are slower, gain signal can be adjusted to and have larger numerical value, so that the amplitude of disturbing signal strengthens, accelerating the movement of target electrical quantity, and when frequency or change in voltage are very fast, can suitably the numerical value of gain signal be turned down, so that the amplitude of disturbing signal reduces, to keep system stability.
In step 4012, produce the isolated island disturbing signal.In one embodiment, can by the fixing extremely variation of detected electrical quantity of yield value of effect, produce the isolated island disturbing signal.For example, this isolated island disturbing signal can comprise q shaft current disturbing signal, idle disturbing signal or its combination.In another execution mode, also can produce by the dynamic gain that produces in the step 4006 the isolated island disturbing signal, so that the amplitude of isolated island disturbing signal can be adjusted.
In step 4014, produce the disturbance compensation signal, to eliminate or to reduce because the caused unexpected variation of isolated island disturbing signal.In one embodiment, this disturbance compensation signal can comprise q shaft voltage compensating signal, and it is applied into elimination or reduces owing to changing at q axle control loop 187 injection q shaft current disturbing signals or reactive power disturbance signal etc. and in the unexpected active power that d axle control loop produces.In another execution mode, this step 4014 also can produce disturbance overcompensation signal.This disturbance overcompensation signal not only can be eliminated above-mentioned unexpected variation, and for example active power changes, and can contribute other disturbance quantity, with disturbing signal that step 4012 is produced with identical type of action, the movement of promotion target electrical quantity.
In step 4016, produce the control signal of control converter device running based on above-mentioned isolated island disturbing signal and disturbance compensation signal at least.This control signal can comprise the switching signal of opening or closing the semiconductor switch device in the converter device.
In step 4018, judge whether one or more electrical parameter values exceeds default normal range (NR).More specifically, in one embodiment, this determining step 4018 can judge whether the frequency of these net side converter 32 outputs exceeds normal frequency range, perhaps this determining step 4018 can judge also whether the voltage of these net side converter 32 outputs exceeds normal voltage range, and perhaps this determining step 4018 can judge simultaneously also whether these net side converter 32 output frequencies and output voltage exceed respectively normal frequency range and normal voltage range.If the one in this one or more electrical quantity or many persons are judged out when exceeding its normal value range, the method flow process 4000 turns to step 4022 to carry out; And if the one in this one or more electrical quantity or many persons are judged out when not exceeding its normal value range, the method flow process 4000 turns to step 4002 to carry out, to proceed the isolated island condition detection.
In step 4022, the affirmative determination that response determining step 4018 has been done also is that photovoltaic energy converting system 20 operates in island state, the protection action of starting-up response.In one embodiment, this protection action is for opening the switch that is connected between photovoltaic energy converting system 20 and the local load 36, to cut off Power supply between the two.In another execution mode, also can be directly with the converter device 24 in the photovoltaic energy converting system 20 for example net side converter 32 close, to stop to export energy.
Although describe the present invention in conjunction with specific execution mode, those skilled in the art will appreciate that and to make many modifications and modification to the present invention.Therefore, recognize, the intention of claims is to be encompassed in all such modifications and the modification in true spirit of the present invention and the scope.

Claims (26)

1. energy conversion system, it is characterized in that: this energy conversion system comprises converter device and inverter controller; This converter device is configured for the input power conversion that energy source is provided and becomes the output energy; This inverter controller and this converter device are electrically connected, and this inverter controller is configured for real component and the idle component of regulation output energy; This inverter controller comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this converter device output, and produce isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least, this isolated island protection module also is configured to this isolated island disturbing signal and disturbance compensation signal function are become to regulate in this output energy any one in the real component and idle component or all, shifts out outside the normal range (NR) with the electrical parameter values that will measure when the generation isolated island situation.
2. energy conversion system as claimed in claim 1, it is characterized in that: this isolated island protection module comprises the frequency change detecting unit, disturbance generation unit and compensating unit; This frequency change detecting unit is configured for and receives the frequency signal that the phase-locked loop apparatus in this energy conversion system obtains, and produces frequency variation signal based on this frequency signal; This disturbance generation unit is configured to receive this frequency variation signal, and produces this isolated island disturbing signal based on this frequency variation signal, shifts out normal frequency range with the frequency values that will export energy; This compensating unit and this disturbance generation unit are electrically connected, and this compensating unit is configured for and produces this disturbance compensation signal, to be used for compensation by the caused unexpected variable quantity of isolated island disturbing signal.
3. energy conversion system as claimed in claim 2, it is characterized in that: this isolated island disturbing signal comprises reactive current disturbing signal or reactive power disturbance signal.
4. energy conversion system as claimed in claim 2, it is characterized in that: this isolated island disturbing signal comprises reactive current disturbing signal and reactive power disturbance signal.
5. energy conversion system as claimed in claim 2, it is characterized in that: this disturbance compensation signal comprises q shaft voltage compensating signal.
6. energy conversion system as claimed in claim 2, it is characterized in that: this compensating unit also is configured to produce disturbance overcompensation signal; When the isolated island situation occurs, this disturbance overcompensation signal node should the isolated island disturbing signal so that the frequency of this converter device output accelerates to shift out normal frequency range.
7. energy conversion system as claimed in claim 2, it is characterized in that: this isolated island protection module further comprises frequency change rate detecting unit and dynamic gain adjustment unit, and this frequency change rate detecting unit is configured to produce the frequency change rate signal based on this frequency variation signal; This dynamic gain adjustment unit and this frequency change rate detecting unit are electrically connected, this dynamic gain adjustment unit is configured to produce corresponding dynamic gain signal based on this frequency change rate signal, this dynamic gain signal is applied this disturbance generation unit, to be used for dynamically adjusting the amplitude of the isolated island disturbing signal that this disturbance generation unit produced.
8. energy conversion system as claimed in claim 1, it is characterized in that: this isolated island protection module comprises the change in voltage detecting unit, disturbance generation unit and compensating unit; This change in voltage detecting unit is configured for and receives the voltage signal that the voltage transformation module in this energy conversion system obtains, and produces voltage change signal based on this voltage signal; This disturbance generation unit is configured to receive this voltage change signal, and producing this isolated island disturbing signal based on this voltage change signal, the frequency values that shifts out normal voltage range or will export energy with the magnitude of voltage that will export energy shifts out outside the normal frequency range; This compensating unit and this disturbance generation unit are electrically connected, and this compensating unit is configured for and produces this disturbance compensation signal, to be used for compensation by the caused unexpected variable quantity of isolated island disturbing signal.
9. energy conversion system as claimed in claim 8, it is characterized in that: this disturbance compensation signal comprises d shaft voltage compensating signal.
10. energy conversion system as claimed in claim 8, it is characterized in that: this compensating unit also is configured to produce disturbance overcompensation signal; When the isolated island situation occurs, this disturbance overcompensation signal node should the isolated island disturbing signal so that the voltage of this converter device output or frequency accelerate to move out normal voltage range or frequency range.
11. energy conversion system as claimed in claim 9, it is characterized in that: this isolated island protection module further comprises voltage change ratio detecting unit and dynamic gain adjustment unit, and this voltage change ratio detecting unit is configured for based on this voltage change signal and produces the voltage change ratio signal; This dynamic gain adjustment unit and this voltage change ratio detecting unit are electrically connected, this dynamic gain adjustment unit is configured to produce corresponding dynamic gain signal based on this voltage change ratio signal, this dynamic gain signal is applied this disturbance generation unit, to be used for dynamically adjusting the amplitude of the isolated island disturbing signal that this disturbance generation unit produced.
12. an energy conversion system is characterized in that: this energy conversion system comprises converter device and inverter controller; This converter device is configured for the input power conversion that energy source is provided and becomes the output energy; This inverter controller and this converter device are electrically connected, and this inverter controller is configured for real component and the idle component of regulation output energy; This inverter controller comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured frequency variation signal of this converter device output and frequency change rate signal, and produces isolated island disturbing signal and disturbance compensation signal according to the frequency variation signal of this measurement and frequency change rate signal at least.
13. an energy conversion system is characterized in that: this energy conversion system comprises converter device and inverter controller; This converter device is configured for the input power conversion that energy source is provided and becomes the output energy; This inverter controller and this converter device are electrically connected, and this inverter controller is configured for real component and the idle component of regulation output energy; This inverter controller comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured voltage change signal of this converter device output and voltage change ratio signal, and produces isolated island disturbing signal and disturbance compensation signal according to the voltage change signal of this measurement and voltage change ratio signal at least.
14. an energy conversion system is characterized in that: this energy conversion system comprises converter device and inverter controller; This converter device is configured for the input power conversion that energy source is provided and becomes the output energy; This inverter controller and this converter device are electrically connected, this inverter controller comprises the first control loop and the second control loop, this first control loop is configured for the real component of regulating this output energy, and this second control loop is configured to regulate the idle component of this output energy; This inverter controller also comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this converter device output, and produce isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least, this isolated island protection module also is configured to this isolated island disturbing signal is applied to this second control loop, so that the idle component of this output energy is done disturbance, this isolated island protection module also is configured to this disturbance compensation signal function to this second control loop, the voltage instruction that this second control loop is produced compensates, and keeps stable with the real component of keeping this first control loop when acting on this isolated island disturbing signal.
15. an energy conversion system is characterized in that: this energy conversion system comprises converter device and inverter controller; This converter device is configured for the input power conversion that energy source is provided and becomes the output energy; This inverter controller and this converter device are electrically connected, this inverter controller comprises the first control loop and the second control loop, this first control loop is configured for the real component of regulating this output energy, and this second control loop is configured to regulate the idle component of this output energy; This inverter controller also comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this converter device output, and produce isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least, this isolated island protection module also is configured to this isolated island disturbing signal is applied to this first control loop, so that the real component of this output energy is done disturbance, this isolated island protection module also is configured to this disturbance compensation signal function to this first control loop, the voltage instruction that this first control loop is produced compensates, and keeps stable with the idle component of keeping this second servo loop when acting on this isolated island disturbing signal.
16. inverter controller, it is configured for the control converter device and carries out the power conversion operation, it is characterized in that: this inverter controller comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this converter device output, and produce isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least, this isolated island protection module also is configured to this isolated island disturbing signal and disturbance compensation signal function are become to regulate in this output energy any one in the real component and idle component or all, shifts out outside the critical field with the electrical parameter values that will measure when the generation isolated island situation.
17. inverter controller, it is configured for the control converter device and carries out the power conversion operation, it is characterized in that: this inverter controller comprises the first control loop and the second control loop, this first control loop is configured for the real component of regulating the output energy that this converter device provides, and this second control loop is configured to regulate the idle component of the output energy that this converter device provides; This inverter controller also comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this converter device output, and produce isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least, this isolated island protection module also is configured to this isolated island disturbing signal is applied to this second control loop, so that the idle component of this output energy is done disturbance, this isolated island protection module also is configured to this disturbance compensation signal function to this second control loop, the voltage instruction that this second control loop is produced compensates, and keeps stable with the real component of keeping this first control loop when acting on this isolated island disturbing signal.
18. inverter controller, it is configured for the control converter device and carries out the power conversion operation, it is characterized in that: this inverter controller comprises the first control loop and the second control loop, this first control loop is configured for the real component of regulating the output energy that this converter device provides, and this second control loop is configured to regulate the idle component of the output energy that this converter device provides; This inverter controller also comprises the isolated island protection module, the output of this isolated island protection module and this converter device electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this converter device output, and produce isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least, this isolated island protection module also is configured to this isolated island disturbing signal is applied to this first control loop, so that the real component of this output energy is done disturbance, this isolated island protection module also is configured to this disturbance compensation signal function to this first control loop, the voltage instruction that this first control loop is produced compensates, and keeps stable with the idle component of keeping this second control loop when acting on this isolated island disturbing signal.
19. one kind is used for energy conversion system is carried out the method that isolated island detects, it is characterized in that: the method comprises the steps: at least
Receive the measured electrical quantity of this energy conversion system output;
At least produce isolated island disturbing signal and disturbance compensation signal based on this electrical quantity;
Act on this isolated island disturbing signal, when the isolated island situation occurs, this electrical quantity is shifted out outside the normal range (NR); And
Act on this disturbance compensation signal, to compensate by the caused unexpected variable quantity of isolated island disturbing signal.
20. method as claimed in claim 19 is characterized in that: the method also comprises the steps:
At least produce disturbance overcompensation signal based on this electrical quantity;
Act on this disturbance overcompensation signal, with in conjunction with this isolated island disturbing signal, this electrical quantity is accelerated to shift out outside this normal range (NR).
21. method as claimed in claim 19, it is characterized in that: this comprises based on the step of this electrical quantity generation isolated island disturbing signal and disturbance compensation signal at least: measured according to this energy conversion system output at least frequency variation signal, perhaps voltage change signal, perhaps frequency variation signal and voltage change signal in conjunction with producing this isolated island disturbing signal and disturbance compensation signal.
22. method as claimed in claim 19 is characterized in that: the method also comprises the steps:
Produce electrical quantity rate of change signal based on this electrical quantity;
Produce corresponding dynamic gain signal based on this electrical quantity rate of change signal; And
Act on this dynamic gain signal to regulate the amplitude of this isolated island disturbing signal.
23. a method that is used for energy conversion system is carried out island protect, it is characterized in that: the method comprises the steps: at least
Receive the measured electrical quantity of this energy conversion system output;
At least produce isolated island disturbing signal and disturbance compensation signal based on this electrical quantity;
Act on this isolated island disturbing signal, when the isolated island situation occurs, this electrical quantity is shifted out outside the normal range (NR);
Act on this disturbance compensation signal, to compensate by the caused unexpected variable quantity of isolated island disturbing signal; And
When the measured electrical quantity of this output is judged out when exceeding this normal range (NR), make this energy conversion system stop to export energy.
24. a photovoltaic energy converting system is characterized in that: this photovoltaic energy converting system comprises dc bus, photovoltaic current transformer and photovoltaic controller; This dc bus is configured for and receives the direct current energy that the photovoltaic energy source provides; This photovoltaic current transformer is configured to convert the direct current energy at this dc bus place to AC energy; This photovoltaic controller comprises the isolated island protection module, the output of this isolated island protection module and this photovoltaic current transformer electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this photovoltaic current transformer output, and at least according to electrical parameter values generation isolated island disturbing signal and the disturbance compensation signal of this measurement, this isolated island protection module also is configured to become the electrical parameter values that will measure when the isolated island situation occurs to shift out outside the critical field with the disturbance compensation signal function this isolated island disturbing signal.
25. photovoltaic energy converting system as claimed in claim 24, it is characterized in that: this photovoltaic energy converting system also comprises the maximum power point tracking device, and this maximum power point tracking device is configured to produce the direct voltage reference signal based on the photovoltaic voltage signal and the photovoltaic current signal that measure at this place, photovoltaic energy source; Wherein, when the isolated island situation occured, this isolated island disturbing signal was revised this direct voltage reference signal.
26. a photovoltaic energy converting system is characterized in that: this photovoltaic energy converting system comprises dc bus, photovoltaic current transformer and photovoltaic controller; This dc bus is configured for and receives the direct current energy that the photovoltaic energy source provides; This photovoltaic current transformer is configured to convert the direct current energy at this dc bus place to AC energy; This photovoltaic controller comprises d axle control loop and q axle control loop, this d axle control loop is configured to regulate the real component in this photovoltaic current transformer output AC energy, and this q axle control loop is configured to regulate the idle component in this photovoltaic current transformer output AC energy; This photovoltaic controller also comprises the isolated island protection module, the output of this isolated island protection module and this photovoltaic current transformer electrically communicates to connect, this isolated island protection module is configured to receive the measured electrical parameter values of this photovoltaic current transformer output, and produce isolated island disturbing signal and disturbance compensation signal according to the electrical parameter values of this measurement at least, this isolated island protection module also is configured to this isolated island disturbing signal is applied to this d axle control loop, so that the real component of this output energy is done disturbance, this isolated island protection module also is configured to this disturbance compensation signal function to this d axle control loop, the voltage instruction that this d axle control loop is produced compensates, and keeps stable with the idle component of keeping this q axle control loop when acting on this isolated island disturbing signal.
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