CN104811064A - Energy conversion system, photovoltaic energy conversion system and method - Google Patents

Abstract

The invention relates to an energy conversion system, a photovoltaic energy conversion system and a method. The method comprises at least the following steps that: at least a maximum phase angle limiting signal and minimum phase angle limiting signal are generated at least based on current threshold values related to a converter device; a phase angle limiting adjustment signal is generated at least based on a direct current voltage instruction signal and an actual voltage signal related to the direct current link; the phase angle limiting adjustment signal is utilized to adjust at least one of the maximum phase angle limiting signal and the minimum phase angle limiting signal; and at least one of the maximum phase angle limiting signal and the minimum phase angle limiting signal is utilized to limit the phase angle instruction signal.

Description

Energy conversion system, photovoltaic energy conversion system and method

Technical field

Execution mode disclosed by the invention relates to system and method, particularly a kind of system and method that can be used for carrying out output current and DC bus-bar voltage cooperation control.

Background technology

Comprise such as photovoltaic power generation apparatus, wind electricity generating system etc., at interior energy conversion system, are developed into for replacing traditional Blast Furnace Top Gas Recovery Turbine Unit (TRT), such as, gradually based on the Blast Furnace Top Gas Recovery Turbine Unit (TRT) etc. of fossil fuel.Energy conversion system known is at least partially configured to carry out grid-connected connection, the power conversion obtained from such as renewable energy resource etc. can be become to meet the energy of grid requirements by it, such as there are specific voltage and frequency etc., and by the energy feed-in electrical network after conversion.

In order to strengthen the control ability of the output current to the electrical conversion systems based on voltage source modelling, industry has proposed a kind of phase current control algolithm or control method.This phase current control algolithm or method are when reality performs, at least provide the amplitude of voltage magnitude restricting signal to voltage command signal to limit based on the current threshold preset and/or provide the phase angle of phase angle restricting signal to phase angle command signal to limit, come indirectly to control the electric current that the converter of electrical conversion systems exports with this, therefore, can, when there is such as low power event and/or no-voltage event, avoid the semiconductor device in converter damaged.

In addition, when actual motion, also wish to control the voltage of DC bus in electrical conversion systems, make it maintain constant numerical value or in acceptable voltage range.But the DC bus-bar voltage control algolithm performed in traditional electrical conversion systems still faces suitable challenge when running into transient affair or electric network fault.

Therefore, be necessary to provide a kind of system and method for improvement solve above-mentioned technical problem or meet above-mentioned technical need.

Summary of the invention

Because the technical problem mentioned above or technical need, one aspect of the present invention is to provide a kind of energy conversion system.This energy conversion system comprises DC link, converter device and inverter controller.This converter device is connected with this DC link, and this converter device is configured to change the direct current energy that this DC link provides and provide AC energy.This inverter controller is connected with this DC link and this convertor device, this converter controller comprises mixed DC voltage and output current control module, and this mixed DC voltage and output current control module are used for limiting the output current of the AC energy that this converter device provides when this electrical conversion systems runs at least one transient affair and regulating the direct voltage of this DC link.Wherein, this mixed DC voltage and output current control module comprise phase angle regulation device, direct current voltage regulator and demand limiter; This phase angle regulation device is for generation of phase angle instruction.This direct current voltage regulator is used at least producing phase angle based on direct voltage command signal and the actual DC voltage signal relevant to this DC link and limits and adjust signal.This demand limiter is connected with this phase angle regulation device and this direct current voltage regulator, this demand limiter is used at least producing at least one maximal phase parallactic angle restricting signal and minimum phase angle restricting signal based on the current threshold relevant to this converter device, and this maximal phase parallactic angle restricting signal and this minimum phase angle restricting signal are used for limiting this phase angle command signal.This demand limiter also adjusts at least one in this maximal phase parallactic angle restricting signal and minimum phase angle restricting signal for using this phase angle to limit adjustment signal.

Another aspect of the present invention is to provide a kind of for detecting the method run with energy conversion system, and this energy conversion system comprises DC link, converter device and inverter controller.The method at least comprises the steps: at least to produce at least one maximal phase parallactic angle restricting signal and minimum phase angle restricting signal based on the current threshold relevant to this converter device; At least produce phase angle based on direct voltage command signal and the actual voltage signal relevant to this DC link to limit and adjust signal; Use this phase angle to limit adjustment signal and adjust at least one in this maximal phase parallactic angle restricting signal and minimum phase angle restricting signal; And use at least one in this maximal phase parallactic angle restricting signal after this adjustment and this minimum phase angle restricting signal to limit this phase angle command signal.

Another aspect of the present invention is to provide a kind of photovoltaic energy conversion system, and this photovoltaic energy conversion system is connected with electrical network.This photovoltaic energy conversion system comprises DC link, photovoltaic converter and photovoltaic controller; This DC link is configured to receive the direct current energy coming from photovoltaic energy source.This photovoltaic converter is connected with this DC link, and this photovoltaic converter is configured to change the direct current energy that this DC link provides and provide active power to this electrical network, and this photovoltaic controller is connected with this DC link and this photovoltaic converter.This photovoltaic controller is configured to: produce phase angle command signal directly to control the phase angle of the output voltage of this photovoltaic converter; Produce maximal phase parallactic angle restricting signal and minimum phase angle restricting signal for the output current limiting this photovoltaic converter and provide; And at least adjust at least one in this maximal phase parallactic angle restricting signal and minimum phase angle restricting signal based on the voltage difference between direct voltage command signal and the actual voltage signal relevant to this DC link, to adjust the numerical value of the active power provided by this photovoltaic converter, controlled to allow the direct voltage of this DC link.

Energy conversion system provided by the invention, photovoltaic energy conversion system, and associated method etc., by being combined with phase current control algolithm by DC voltage control algorithm, effective control of the direct voltage to DC link can be realized.

Accompanying drawing explanation

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 the energy conversion system providing mixed DC voltage and output current control module;

Figure 2 shows that the module diagram of a kind of execution mode of the photovoltaic energy transformation system providing mixed DC voltage and output current control module;

Figure 3 shows that the summarization module schematic diagram of a kind of execution mode of mixed DC voltage and output current control module;

Figure 4 shows that the detailed module diagram of a kind of execution mode of mixed DC voltage and output current control module;

Figure 5 shows that the detailed module diagram of the another kind of execution mode of mixed DC voltage and output current control module;

Figure 6 shows that the detailed module diagram of the another kind of execution mode of mixed DC voltage and output current control module;

Figure 7 shows that the simplification circuit model schematic of a kind of execution mode of net side converter and electrical network;

Figure 8 shows that the voltage vector schematic diagram of a kind of execution mode relevant with output current control module to performing mixed DC voltage;

Figure 9 shows that the voltage vector schematic diagram of the another kind of execution mode relevant with output current control module to performing mixed DC voltage;

Figure 10 shows that the various signal waveform schematic diagrames of a kind of execution mode produced at execution mixed DC voltage and output current control module;

Figure 11 shows that the detailed module diagram of the another kind of execution mode of mixed DC voltage and output current control module;

Figure 12 shows that the voltage vector schematic diagram performing the mixed DC voltage another kind of execution mode relevant with output current control module; And

Figure 13 shows that the flow chart of a kind of execution mode controlling the method that energy conversion system runs.

Embodiment

One or more execution mode and energy conversion system that the present invention discloses or more specifically with energy generating system or electrical conversion systems relevant, especially, the system and method being performed output current control and DC tache voltage control by coordination mode is related to.In some embodiments, at least partially parameter relevant to the output current of electrical conversion systems dynamically can regulate according to the regulatory demand of the direct voltage of DC link, has reached the control of harmony.For example, in the execution mode that some are concrete, the phase angle restricting signal for limiting the output current generation overcurrent problem of current transformer can depart from DC tache voltage that is normal or that expect DC tache voltage deviation signal according to the direct voltage characterizing actual DC link adjusts dynamically.In some embodiments, the reactive power that can also provide as required is to adjust phase angle restricting signal.

Exposing system of the present invention and method at least can obtain following technological merit or technique effect: one of them technological merit or technique effect are the control of DC tache voltage can be made quicker by DC tache voltage control algolithm and output current control algolithm being integrated together; The overcurrent problem that another technological merit or technique effect current transformer run into and the overvoltage problem that DC link runs into can be avoided or be alleviated, and make this electrical conversion systems can successfully pass through one or more transient event; Another technological merit or technique effect are overvoltage by alleviating DC link or under voltage problem, and electrical conversion systems can be avoided to suffer unnecessary tripping operation (trip).For the personnel that this area has usual knowledge, by read hereafter by reference to the accompanying drawings the detailed description done, be easy to understand that the specific embodiment of the invention can also produce other technologies advantage or technique effect.

One or more embodiment of the present invention below will be described.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 do 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 the objectives of developer; or in order to meet that system is correlated with or that business is relevant restriction; usually can make various concrete decision-making, and this also can change to another kind of execution mode from a kind of execution mode.In addition, it will also be appreciated that, although effort done in this development process may be complicated and tediously long, but for those of ordinary skill in the art relevant to content disclosed by the invention, some designs that the basis of the technology contents of disclosure exposure is carried out, manufacture or production etc. changes just conventional technological means, not should be understood to content disclosed by the invention insufficient.

Unless otherwise defined, the technical term used in the present specification and claims or scientific terminology should be in the technical field of the invention the ordinary meaning that the personage with general technical ability understands." first " or " second " that use in this specification and claims and similar word do not represent any order, quantity or importance, and are only used to distinguish different parts.The similar word such as " one " or " one " does not represent restricted number, but represents to there is at least one." or " comprise in cited project any one or all." comprise " or the similar word such as " comprising " mean to appear at " comprising " or " comprising " before element or object contain the element or object and equivalent element thereof that appear at " comprising " or " comprising " presented hereinafter, do not get rid of other elements or object." connection " or " being connected " etc. similar word be not defined in physics or the connection of machinery, no matter but can comprise electrical connection, be direct or indirectly.In addition, the set that " circuit " or " Circuits System " and " controller " etc. can comprise single component or directly or be indirectly connected by multiple active member or passive device, such as one or more integrated circuit (IC) chip, to provide the corresponding function described.

First, refer to Fig. 1, it is depicted as the outline module diagram of a kind of execution mode of the energy conversion system 10 that the present invention discloses.Energy conversion system 10 can comprise photovoltaic energy conversion system referred in this, wind energy converting system, fuel cell energy converting system, hydraulic energy or tidal energy energy conversion system, and the combination etc. of above-mentioned various energy conversion system.As shown in Figure 1, this energy conversion system 10 comprises the converter device 14 be connected electrically between energy source 12 and load 16, this converter device 14 can be configured to by the first electric energy 18(of obtaining from energy source 12 such as, direct current energy or AC energy) convert the second electric energy 22(to such as, direct current energy or AC energy), and this second electric energy 22 is supplied to load 16.Under a specific application scenario, this load 16 can be electrical network, and it expects that the second electric energy 22 obtained can be threephase AC electric energy, and has specific voltage and/or frequency (such as, 60 hertz or 50 hertz).In other embodiments, this load 16 also can comprise power consumpting device such as motor (motor) etc.

As shown in Figure 1, this converter device 14 also communicates to connect with inverter controller 30.Although in the execution mode shown in Fig. 1, this converter device 14 and inverter controller 30 are shown as independent element, and in other embodiments, this converter device 14 and inverter controller 30 also can integrate, to form a single device.This inverter controller 30 is configured to perform one or more control algolithm, operates relevant various electrical characteristic parameters etc. to regulate or to adjust to this converter device 14.For example, in order to meet the demand of electrical network or can safe and stable running be carried out in order to ensure this energy conversion system 10, this inverter controller 30 can be configured to the active power exported converter device 14, reactive power, power factor (PF), voltage, electric current, frequency, the parameters such as phase angle carry out regulation and control.

According to the specific configuration mode of one provided by the invention, this inverter controller 30 can comprise mixed DC voltage and output current control module 28, this mixed DC voltage and output current control module 28 can pass through computer software, algorithm or program command realize, and can be stored on the storage medium (non-transitory computer-readable storage media) of non-transient computer-readable.This inverter controller 30 can comprise one or more processor, for this software algorithm of execution or program, to realize the various functions needing to realize described here.In interchangeable execution mode, this mixed DC voltage and output current control module 28 also can be realized by hardware circuit, or also can be realized by the form of combination of hardware software.Especially, when this mixed DC voltage and output current control module 28 are performed, cooperation control can be carried out, to limit the output current of this converter device 14 and to regulate the direct voltage of this DC link 15.

In certain embodiments, this mixed DC voltage and output current control module 28 can communicate to connect with the output of this converter device 14, or more particularly, the tie point 24 be defined between this converter device 14 and load or electrical network 16 connects, one or more feedback signal can be obtained by this tie point 24, such as alternating voltage and/or ac current signal etc., it represents alternating voltage and the alternating current of converter device 14 output reality.When running at least one transient event (transient event), such as, when low power event or no-voltage event, this converter device 14 possibly cannot provide active power to this load 16, and this can cause the electric current of converter device 14 output to rise rapidly.Now, this mixed DC voltage and output current control module 28 are also configured at least produce control signal 32 based on one or more feedback signal 26 of this acquisition and one or more current threshold 33, wherein, this current threshold 33 limits the maximum of the electric current flowed out from this converter device 2.The control signal 32 that this converter device 14 sends according to this inverter controller 30 operates in a particular manner, exceedes this current threshold to avoid the output current of this converter device 14.

In the execution mode shown in Fig. 1, this mixed DC voltage and output current control module 28 also communicate to connect with DC link 15, to receive the feedback signal 17 of the actual DC voltage representing this DC link 15.At generation transient affair, such as, when low power event or no-voltage event, this DC link 15 may run into overvoltage situation or under voltage situation.This mixed DC voltage and output current control module 28 are also configured at least adjust this control signal 32 according to direct voltage feedback signal 17 and one or more voltage set point signal 35, wherein, this voltage set point signal 35 can represent expectation DC voltage value or the DC voltage range value of this DC link 15.This converter device 14 operates according to the control signal 32 of this adjustment, regulates according to this voltage setting signal 35 to allow the direct voltage of this DC link 35 reality.

Next, refer to Fig. 2, it is depicted as the module diagram of a kind of execution mode of photovoltaic energy conversion system 100.This photovoltaic energy conversion system 100 can be configured to perform the mixed DC voltage shown in Fig. 1 and output current control module 28.As shown in Figure 2, this photovoltaic energy conversion system 100 comprises photovoltaic converter module 104, this photovoltaic converter module 104 is used to convert the direct current energy provided from photovoltaic energy source 102 AC energy with suitable voltage and frequency to, and this AC energy is supplied to electrical network 110.In one embodiment, this photovoltaic energy source 102 can comprise one or more photovoltaic array, and each photovoltaic array has multiple photovoltaic cells linked together with in parallel and/series system, and the photovoltaic array in this photovoltaic energy source 102 or photovoltaic cells convert photovoltaic radiant energy to direct current energy according to photoelectric effect.

In one embodiment, namely photovoltaic converter module 104 shown in Fig. 2 is based on the framework of two-stage type, and it comprises photovoltaic side converter 106(also near the current transformer of side, photovoltaic energy source 102) and the current transformer of net side converter 108(also i.e. close electrical network 110 side).This photovoltaic side converter 106 can comprise DC-DC converter, such as Boost DC-DC convertor, and it can raise the direct voltage being changed output by photovoltaic energy source 12, and the direct voltage after raising is supplied to DC link 128.This DC link (or also referred to as DC bus, DC link) 128 can comprise one or more capacitor, magnitude of voltage in order to the direct voltage by DC link 128 maintains in specific numerical value or number range, thus can control the energy flow from DC link 128 to electrical network 110.This net side converter 108 can comprise DC-AC current transformer, in order to the direct voltage at DC link 128 place to be converted to the alternating voltage with suitable frequency, phase place and/or amplitude that applicable AC network 18 is carried.In some embodiments, photovoltaic energy conversion system 100 can further include net side filter 134, this net side filter 134 is connected to any point being defined in circuit between net side converter 108 and electrical network 18, this net side filter 134 is used to remove the unexpected signal sent by net side converter 108, such as, be included in the high frequency harmonic signals in output AC electric energy.Be understandable that, although do not illustrate on figure, one or more other elements, such as transformer, the devices such as circuit breaker, also can be connected between net side converter 108 and electrical network 110, to realize corresponding function.

In one embodiment, photovoltaic energy conversion system 100 shown in Fig. 2 comprises photovoltaic converter control device 112 further, this photovoltaic converter control device 112 is configured to perform control algolithm according to various system feedback signal and command signal, to control photovoltaic side converter 106 and net side converter 108 operates.More specifically, in one embodiment, this photovoltaic converter control device 112 comprises the photovoltaic side controller 114 be connected with photovoltaic converter 106 and the net side controller 116 be connected with net side converter 108, and this photovoltaic side controller 114 and this net side controller 116 are configured to the running being responsible for respectively controlling photovoltaic converter 106 and net side converter 108.

The present invention for convenience of description, in the embodiment shown in figure 2, this photovoltaic side controller 114 illustrates into discrete module in block diagram form with this net side controller 116, but, in some embodiments, this photovoltaic side controller 114 and this net side controller 116 also can be realized by single controller.This photovoltaic side controller 114 and this net side controller 116 can comprise any suitable programmable circuit or device referred in this, comprise digital signal processor (Digital Signal Processor, DSP), field programmable gate array (Field Programmable Gate Array, FPGA), programmable logic controller (PLC) (Programmable Logic Controller, and application-specific integrated circuit (ASIC) (Application Specific Integrated Circuit, ASIC) etc. PLC).In some embodiments, remove outside other elements, this photovoltaic side controller 114 and photovoltaic side converter 106 can be assembled in a single housing.Similarly, remove outside other elements, this net side converter 108 and net side controller 116 can be assembled in a single housing.Further, remove outside other elements, this photovoltaic side controller 114, photovoltaic side converter 106, net side converter 108 and net side controller 116 can be assembled in a single housing.

In one embodiment, the maximum power point reference signal 158 that this photovoltaic side controller 114 can be configured at least provide based on maximum power point tracking device 126 provides photovoltaic side control signal 148 to photovoltaic side converter 106.This maximum power point reference signal 158 is produced by specific mode, such as, to guarantee this photovoltaic energy source 102 under changing circumstances, the light radiation intensity changed and temperature etc., maximum electrical power can be provided all the time to export.This maximum power point reference signal 158 can comprise voltage, electric current and/or power reference signal, and these reference signals can by performing specific maximum power point tracking algorithm such as, and disturbance observation method or conductance increment method etc. upgrade.Further, when performing maximum power point tracking algorithm, the photovoltaic current feedback signal 122 obtained by one or more current sensor 120 and the photovoltaic voltage feedback signal 124 obtained by one or more voltage sensor 118 can be used.

Please consult Fig. 2 further, in one embodiment, this net side controller 116 can be configured at least based on active power command signal 144, reactive power command signal 146, the various electrical characteristic parameters that the voltage feedback signal 140 measured by one or more voltage sensor 136 and the current feedback signal 142 measured by one or more current sensor 138 regulate or control this net side converter 108 to export, comprise active power and reactive power etc.This net side controller 116 can also be configured at least regulate based on the DC bus-bar voltage feedback signal 130 measured by voltage sensor 129 and DC bus-bar voltage command signal 132 or control the direct voltage of DC link 128.

Please consult Fig. 2 further, this net side controller 116 can comprise mixed DC voltage and output current control module 117, and this mixed DC voltage and output current control module 117 can pass through hardware, and the form of software or combination of hardware software realizes.In one embodiment, this mixed DC voltage and output current control module 117 are configured at least produce net side control signal 150 based on current feedback signal 142 and one or more current threshold signal or numerical value 119, exceed maximum current threshold value to avoid the output current of this net side converter 108.

In some embodiments, this mixed DC voltage and output current control module 117 are also configured to adjust this net side control signal 150 based on direct voltage feedback signal 130 and direct voltage command signal 132, are adjusted to specific numerical value or value range to make the direct voltage of this DC link 128.

Figure 3 shows that a kind of mixed DC voltage of execution mode and the summarization module schematic diagram of output current control module 200.In some embodiments, this mixed DC voltage and output current control module 200 are designed to based on voltage source control structure.Refer to that its main control variables comprises amplitude and the phase angle of AC voltage in a kind of concrete control system execution mode at this so-called " voltage source control framework ".

In the execution mode shown in Fig. 3, this mixed DC voltage and output current control module 200 comprise phase angle regulation device 210, voltage magnitude adjuster 220, demand limiter 230, direct current voltage regulator 250 and signal generation unit 240.

In one embodiment, this phase angle regulation device 210 receives active power command signal 212 and active power feedback signal 214, and at least produces phase angle command signal 216 based on this active power command signal 212 and active power feedback signal 214.The active power exported by net side converter 108 is wished in the representative of this active power command signal 212, and it can be given by grid operator, and this active power feedback signal 214 then represents the actual active power exported by net side converter 108.This active power feedback signal 214 can obtain by current on line side feedback signal 142 being as shown in Figure 2 multiplied with voltage on line side feedback signal 152.The phase angle command signal 216 produced by this phase angle regulation device 210, can have some to be out of shape in a particular embodiment.Such as, in one embodiment, this phase angle command signal 216 represents the AC voltage of net side converter 108 and line voltage or the phase shift closed between some institutes of electrical network 18 place power taking pressure or phase difference.In another execution mode, this phase angle command signal 216 can also represent the phase place of net side converter 108 alternating voltage that this hope obtains.The phase place of this net side converter 108 alternating voltage can by being added the phase place of voltage on line side with above-mentioned phase difference and obtaining.The AC voltage of net side converter 108 described herein can be the alternating voltage of net side converter 108 output.In interchangeable execution mode, the AC voltage of this net side converter 108 can also be considering the builtin voltage under net side converter 108 internal driving situation.Furthermore, in some embodiments, the AC voltage of this net side converter 108 can also for the voltage recorded along arbitrfary point transmission line from net side converter 108 output.

In one embodiment, this voltage magnitude adjuster 250 receives reactive power command signal 222 and reactive power feedback signal 224, and produces voltage magnitude command signal 226 according to the signal of this reception.The reactive power exported by net side converter 108 is wished in the representative of this reactive power command signal 222, it can be given by grid operator, and this reactive power feedback signal 224 represents the reactive power of the measured actual transmission exported by net side converter 108.This reactive power feedback signal 224 can obtain by current on line side feedback signal 142 being multiplied with voltage on line side feedback signal 140.The representative of this voltage magnitude command signal 226 is desirably in the amplitude of the alternating voltage that this net side converter 108 obtains, and wherein, the alternating voltage of this net side converter 108 can be the alternating voltage of net side converter 108 output.Alternatively, the alternating voltage of this this net side converter 108 also can be at the internal communication voltage considering net side converter inside or virtual impedance.

In one embodiment, this demand limiter 230 can comprise phase current limiter particularly, and its phase angle command signal 216 being configured to produce to this phase angle regulation device 210 provides phase angle restricting signal.In one embodiment, the voltage magnitude command signal 226 that this phase current limiter 230 is also configured to produce to voltage magnitude adjuster 220 provides voltage magnitude restricting signal.This phase angle restricting signal and this voltage magnitude restricting signal produce according to multi-signal or numerical value, such as, and current feedback signal 262, voltage feedback signal 264, current threshold 266 and resistance value 268.

In the execution mode shown in Fig. 3, this direct current voltage regulator 250 is configured at least produce phase angle restriction adjustment signal 256 based on direct voltage command signal 252 and direct voltage feedback signal 254.This phase angle restriction adjustment signal 256 reflects the degree of the actual DC voltage deviation direct voltage command signal 252 of this DC link 128.In one embodiment, this phase angle restriction adjustment signal 256 is used for adjusting phase angle restricting signal by demand limiter 230.The present inventor finds after deliberation, when the direct voltage of this DC link 128 departs from, the active power that can cause exporting from net side converter 120 by adjusting phase angle restricting signal according to this phase angle restriction adjustment signal 256 occurs to increase or reduce, and can realize the control of the direct voltage to DC link 128 by increasing or reduce the active power exported.More specifically, when there is overvoltage situation in this DC link 128, use this phase angle to limit adjustment signal 256 by specific mode and adjust phase angle restricting signal, the increase of the active power that net side converter 108 can be caused to export, thus make further after one or more control cycle, the direct voltage of this DC link 128 declines, and like this, can eliminate or alleviate the overvoltage situation of this DC link 128.Similarly, when there is under voltage situation in this DC link 128, use this phase angle to limit adjustment signal 256 by specific mode and adjust phase angle restricting signal, the minimizing of the active power that net side converter 108 can be caused to export, thus make further after one or more control cycle, the direct voltage of this DC link 128 rises, and like this, can eliminate or alleviate the under voltage situation of this DC link 128.

Please consult Fig. 3 further, the phase angle command signal 232 after adjustment produced by this demand limiter 230 and the voltage magnitude command signal 234 after adjusting are used for producing net side control signal 242 by signal generation unit 240, this net side control signal 242 is applied to net side converter 108, runs according to specific mode to control it.When running into transient event, the electric current that net side converter 108 flows out can control indirectly by the adjustment alternating voltage relevant to net side converter.Therefore, by performing the mixed DC voltage and output current control module 200 that disclose at this, this electrical conversion systems 100 can be made successfully to pass through transient event such as electrical network transient event, the overcurrent problem caused due to transient event to avoid the semiconductor device in this grid side converter 144 and damaged.In addition, by performing this mixed DC voltage and output current control module 200, the direct voltage of DC link 128 also can be made to be controlled effectively.

Figure 4 shows that the detailed module diagram of a kind of execution mode of mixed DC voltage and output current control module 410.As shown in Figure 4, this mixed DC voltage and output current control module 410 comprise the first summator 412, second summator 422, dynamic current threshold computation unit 428, voltage difference computing unit 438, phase angle restricting signal computing unit 444, voltage magnitude restricting signal computing unit the 452, three summator 462, voltage regulator 472, phase angle restricting signal adjustment unit 476, and voltage command signal limiting unit 484.

In one embodiment, this first summator 412 is configured to maximum current threshold signal 414 and current feedback signal negative sequence component 416 to subtract each other, and produce maximum current threshold signal positive sequence component 418, wherein, this maximum current threshold signal 414 presets according to many factors, and the ability such as processing electric current according to this net side converter 108 sets.This current feedback signal negative sequence component 416 can in accordance with known methods from current feedback signal 142(as shown in Figure 2) decompose and obtain.

In one embodiment, this second summator 422 is connected with this first summator 412, to receive this maximum current threshold signal positive sequence component 418.This second summator 422 is also configured to maximum current threshold signal positive sequence component 418 and current feedback signal positive sequence component 424 be subtracted each other, to obtain current deviation signal 426.This current feedback signal positive sequence component 424 also can in accordance with known methods from current feedback signal 142(as shown in Figure 2) decompose and obtain.

In one embodiment, this dynamic current threshold computation unit 428 can comprise proportional and integral controller or any other suitable adjuster, produces dynamic maximum current threshold signal 436 for according to this current deviation signal 426.In some embodiments, this dynamic current threshold computation unit 428 can be provided with higher limit 432 and lower limit 434, carries out amplitude limit for this dynamic maximum current threshold signal 436.In other embodiments, independent clipping element also can be used to carry out amplitude limit to dynamic maximum current threshold signal 436.

In some interchangeable execution modes, except shown in this Fig. 4 by current feedback signal negative sequence component from total current feedback signal filtering, this dynamic power threshold computation unit 428 also can by directly changing this maximum current threshold signal 414 according to negative sequence current signal 142.

In one embodiment, this voltage difference computing unit 438 is configured to according to this dynamic maximum current threshold signal 436 and impedance signal 437 calculating voltage difference signal 442.In other embodiments, this also can not use this dynamic maximum current threshold signal 436, and directly uses default maximum current threshold value 414 and impedance signal 437 to calculate this voltage differential signal 442.In one embodiment, as shown in Figure 7, when the voltage of required control is that converter builtin voltage 716(refers to Fig. 7) time, this impedance signal 437 is internal driving 712 and electric network impedance 714 sum.In other embodiments, when the voltage of required control is that converter terminal voltage 718(refers to Fig. 7) time, this impedance signal 437 is electric network impedance 714.In the specific execution mode of one, this voltage difference computing unit 438 can be configured to use formula below (1) to calculate this voltage differential signal 442:

dV=I _max_d*[(X _brg+X _vir)*j] (l)，

Wherein, dV is voltage differential signal 442, I _{max_d}for dynamic maximum current threshold signal 436, X _brgfor electric network impedance 714, X _virfor internal driving 712.

Please continue to refer to Fig. 4, this voltage differential signal 442 is used for calculating phase angle restricting signal 446,448 by this phase angle restricting signal computing unit 444 and/or is used for calculating voltage amplitude restricting signal 454,456 by this voltage magnitude restricting signal computing unit 452.In the specific execution mode of one, this phase angle restricting signal computing unit 444 is configured to use formula below (2) and formula (3) to calculate this phase angle restricting signal 446,448:

${\mathrm{\θ}}_{\max }=2a\sin \left(\frac{\mathrm{dV}}{{2V}_{g\_\mathrm{potc}}}\right)---\left(2\right),$

θ _min=-θ _max(3),

Wherein, θ _maxfor maximal phase parallactic angle restricting signal 446, θ _minfor the representative of minimum phase angle restricting signal 448, dV by virtual impedance 712 and electric network impedance 714(as shown in Figure 7) voltage differential signal that produces, V _{g_potc}for the voltage measured by the points of common connection adjacent with electrical network 110.

In one embodiment, this voltage magnitude restricting signal computing unit 452 is configured to use formula below (4), (5) and (6) calculate this voltage magnitude restricting signal 454,456:

$V_{\mathrm{mag}\_\mathrm{diff}}=\sqrt{{\mathrm{dV}}^2-{(V_{g\_\mathrm{potc}}*\sin {\mathrm{\θ}}_{\mathrm{real}})}^2}---\left(4\right),$

$V_{\mathrm{mag}\_\max }=V_{g\_\mathrm{potc}}*\cos {\mathrm{\θ}}_{\mathrm{real}}+V_{\mathrm{mag}\_\mathrm{diff}}---\left(5\right),$

$V_{\mathrm{mag}\_\min }=V_{g\_\mathrm{potc}}*\cos {\mathrm{\θ}}_{\mathrm{real}}-V_{\mathrm{mag}\_\mathrm{diff}}---\left(6\right),$

Wherein, V _{mag_max}for maximum voltage amplitude restricting signal 454, V _{mag_min}for minimum voltage amplitude restricting signal 456, θ _realfor actual phase angle signal, V _{mag_diff}for the amplitude of the voltage difference by virtual impedance 712 and electric network impedance 714.

The minimum and maximum phase angle restricting signal 446,448 that this phase angle restricting signal computing unit 444 produces is provided to this phase angle restricting signal adjustment unit 476.This phase angle restricting signal adjustment unit 476 is configured at least one at least adjusted based on phase angle adjustment signal 474 in this minimum and maximum phase angle restricting signal 446.In one embodiment, this phase angle adjustment signal 474 is by voltage regulator 472(such as proportional and integral controller) produce according to direct voltage difference signal 468, wherein, direct voltage command signal 464 and direct voltage feedback signal 466 are subtracted each other by the 3rd summator 462 and obtain by this direct voltage difference signal 468.

In the specific execution mode of one, when direct voltage command signal 464 is less than direct voltage feedback signal 466, also, when this DC link 128 runs into overvoltage situation, this phase angle adjustment signal 474 has negative value.In this case, this phase angle restricting signal adjustment unit 476 can use formula below (7) and formula (8) to produce the minimum and maximum phase angle command signal 478,482 of this adjustment:

θ _{max_new}=θ _max(7),

θ _{min_new}=-θ _dc(8),

Wherein, θ _{max_new}for the maximal phase parallactic angle restricting signal 478, θ after adjustment _{min_new}for the minimum phase angle restricting signal 482, θ after adjustment _dcfor phase angle adjustment signal 474.

As shown in Figure 8, the maximal phase parallactic angle restricting signal θ after adjustment _{max_new}with the maximal phase parallactic angle restricting signal θ before adjustment _maxequal, and its phase angle is just, as two lines 802 and 804 in Fig. 8 the angle that formed.And the minimum phase angle restricting signal θ after adjustment _{min_new}larger than the minimum phase angle restricting signal before adjustment, and its phase angle is just also, as two lines 802 and 806 in Fig. 8 the angle that formed.Be understandable that, minimum phase angle restricting signal 482 is set on the occasion of, this net side converter 108 can be made to provide more active power to export in one or more control cycle ensuing.Because this net side converter 108 provides more active power to export, therefore, the direct voltage at this DC link 128 place will decline gradually, thus the overvoltage situation at this DC link 128 place will be alleviated until eliminate gradually.

In another specific execution mode, when direct voltage command signal 464 is greater than direct voltage feedback signal 466, also, when this DC link 128 runs under voltage situation, this phase angle adjustment signal 474 have on the occasion of.In this case, this phase angle restricting signal adjustment unit 476 can use formula below (9) and formula (10) to produce the minimum and maximum phase angle command signal 478,482 of this adjustment:

θ _{max_new}=-θ _dc(9),

θ _{min_new}=θ _min(10),

Wherein, θ _{max_new}for the maximal phase parallactic angle restricting signal 478, θ after adjustment _{min_new}for the minimum phase angle restricting signal 482, θ after adjustment _dcfor phase angle adjustment signal 474.

As shown in Figure 9, the maximal phase parallactic angle restricting signal θ after adjustment _{max_new}for negative value, as two lines 802 and 814 in Fig. 9 the angle that formed.And the minimum phase angle restricting signal θ after adjustment _{min_new}equal with the minimum phase angle restricting signal before adjustment, as two lines 802 and 812 in Fig. 9 the angle that formed.Be understandable that, maximal phase parallactic angle restricting signal 482 is set to negative value, can make this net side converter 108 in one or more control cycle ensuing, provide less active power to export.Because this net side converter 108 provides less active power to export, therefore, the direct voltage at this DC link 128 place will rise gradually, thus the under voltage situation at this DC link 128 place will be alleviated until eliminate gradually.

Please continue to refer to Fig. 4, the minimum and maximum phase angle restricting signal 478,482 after this adjustment and minimum and maximum voltage magnitude restricting signal 454,456 are provided to this voltage command signal limiting unit 484.In one embodiment, this voltage command signal limiting unit 484 is configured to limit according to 478, the 482 pairs of phase angle command signals 486 of the minimum and maximum phase angle restricting signal after this adjustment, and provides the phase angle command signal 492 of restriction.

This voltage command signal limiting unit 484 is also configured to limit according to minimum and maximum voltage magnitude restricting signal 454,456 pairs of voltage magnitude command signals 488, and provides the voltage magnitude command signal 494 of restriction.In some embodiments, the phase angle command signal 492 of this restriction and the voltage magnitude command signal 494 of restriction can be used for producing net side control signal 242(such as by the signal generation unit 240 shown in Fig. 3, pwm control signal), thus the operation of Controling network side converter 108.

Next, refer to Figure 10, it is depicted as the various signal waveform schematic diagrames of a kind of execution mode produced at the mixed DC voltage performed as shown in Figure 4 and output current control module 410.Wherein, figure 610 shows the three-phase power grid voltage 612,614,616 of closing on measured by the points of common connection of electrical network 110.Figure 620 shows maximal phase parallactic angle restricting signal 622, the actual phase angle 626 that minimum phase angle restricting signal 624 and this net side converter export.Figure 630 shows the feedback direct voltage 632 at DC link 128 place.As shown on these figures, very first time point t0 represents this electrical network and runs into electric network fault, such as, line line fault, and this electric network fault lasts till the second time point t1.Before very first time point t0, this three-phase power grid voltage 612,614,616 have substantially equal amplitude, and phase angle is separated by 120 degree, and, maximal phase parallactic angle restricting signal 622 and minimum phase angle restricting signal 624 have contrary polarity, and the phase angle signal 622 of reality falls into therebetween, and have on the occasion of, provide meritorious power stage to allow this net side converter.After this very first time, electric network fault occurred some t0, the direct voltage of this DC link 128 rises to about 700 volts from about 600 volts gradually, and also, this DC link 128 runs into overvoltage situation.In order to tackle this overvoltage situation, this mixed DC voltage and output current control module 410 are executed as the numerical value regulating or increase minimum phase angle command signal 624, make it have on the occasion of, thus make this net side converter 108 provide more active power to export.Therefore, the direct voltage 632 of this DC link 128 drops to 600 volts from about 700 volts gradually.After this second time t1, because electric network fault disappears, this maximal phase parallactic angle restricting signal 622 and minimum phase angle restricting signal 624 are restored to normal numerical value, and have contrary polarity.Further, this three-phase power grid voltage 612,614,616 is also basic recovers normal, and three has substantially equal amplitude, and its phase angle is then separated by 120 degree.

Figure 5 shows that the mixed DC voltage of another kind of execution mode and the detailed module diagram of output current control module 420.With mixed DC voltage as shown in Figure 4 and output current control module 410 similar, in some embodiments, this mixed DC voltage and output current control module 420 also can pass through hardware, the mode of software or software combined with hardware realizes, and can converter controller 30 as shown in Figure 1 or the net side controller 116 shown in Fig. 2 perform.One of them difference is that the voltage magnitude restricting signal computing unit 452 in this mixed DC voltage and output current control module 420 is configured at least produce minimum and maximum voltage magnitude restricting signal 454,456 based on voltage feedback signal 458.More specifically, in some embodiments, the electrical conversion systems 10,100 shown in Fig. 1 and Fig. 2 can be designed to provide zero reactive power to export electrical network 110 to.In order to meet this reactive power demand, in one embodiment, this voltage magnitude restricting signal computing unit 452 can be configured to use following formula (11) and formula (12) to produce this minimum and maximum voltage magnitude restricting signal 454,456:

V _{mag_max_new}=V _{g_potc}(11),

V _{mag_min_new}=V _{g_potc}(12),

Wherein, V _{mag_max_new}for the maximum voltage amplitude restricting signal 454, V after adjustment _{mag_min_new}for the minimum voltage amplitude restricting signal 456, V after adjustment _{g_potc}for the voltage measured by the points of common connection adjacent with electrical network 110.

As can be seen from formula (11) and formula (12), the minimum and maximum voltage magnitude restricting signal and 454,456 after this adjustment is configured to have equal numerical value.When DC link 128 runs into overvoltage situation, as shown in Figure 8, the vector end of this converter voltage 716 is forced to move along arc section 808, wherein, one end of this arc section 808 is the distal point of the voltage vector 806 with minimum phase angle, and the other end is the distal point of the voltage vector 804 with maximal phase parallactic angle.Similarly, when this DC link 128 runs under voltage situation, as shown in Figure 9, the vector end of this converter voltage 716 is forced to move along arc section 816, wherein, one end of this arc section 816 is the distal point of the voltage vector 812 with minimum phase angle, and the other end is the distal point of the voltage vector 814 with maximal phase parallactic angle.

Please continue to refer to Fig. 5, this minimum and maximum voltage magnitude restricting signal 454,456 is used for limiting voltage magnitude command signal 488 by this voltage command signal limiting unit 484, and produces the voltage magnitude command signal 494 of restriction.Similarly, the phase angle command signal 492 of this restriction and the voltage magnitude command signal 494 of restriction can be used for producing net side control signal 242(such as by the signal generation unit 240 shown in Fig. 3, pwm control signal), thus the operation of Controling network side converter 108.

Figure 6 shows that the mixed DC voltage of another kind of execution mode and the detailed module diagram of output current control module 430.The same with output current control module 410 with mixed DC voltage as shown in Figure 4, in some embodiments, this mixed DC voltage and output current control module 430 also can pass through hardware, the mode of software or software combined with hardware realizes, and can converter controller 30 as shown in Figure 1 or the net side controller 116 shown in Fig. 2 perform.One of them difference is that this mixed DC voltage and output current control module 430 also comprise voltage limiting unit 469, and this voltage limiting unit 469 is connected between the 3rd summator 462 and voltage regulator 472.The direct voltage deviation signal 468 that this voltage limiting unit 469 is configured to the 3rd summator 462 to provide compares with voltage threshold 467, and wherein this voltage threshold 467 is a value characterizing that the fluctuation range that normally can receive occurs this direct voltage feedback signal 466 relative direct voltage command signal 464.More specifically, when this direct voltage deviation signal 468 is less than this voltage threshold 467, this voltage limiting element 469 stops providing signal to this voltage regulator 472.Result is in this condition that DC voltage regulation function is temporarily forbidden in this mixed DC voltage and output current control module 430.Judge that this direct voltage deviation signal 468 is greater than this voltage threshold 467 once this voltage limiting unit 469, just recover this DC voltage regulation function, also be, this direct voltage deviation signal 471 is supplied to this voltage regulator 472 by this voltage limiting unit 469, and produce phase angle adjustment signal 474 by this voltage regulator 472, for this phase angle restricting signal 446,448 of adjustment.

Figure 11 shows that the mixed DC voltage of another kind of execution mode and the detailed module diagram of output current control module 440.With mixed DC voltage as shown in Figure 4 and output current control module 410 similar, in some embodiments, this mixed DC voltage and output current control module 440 also can pass through hardware, the mode of software or software combined with hardware realizes, and can converter controller 30 as shown in Figure 1 or the net side controller 116 shown in Fig. 2 perform.One of them difference is, the mixed DC voltage shown in Figure 11 and output current control module 440 also comprise q shaft current computing unit 415 and d shaft current computing unit 419.This q shaft current computing unit 415 is configured to receiver voltage amplitude command signal 413, and produce q shaft current command signal 417 according to this voltage magnitude command signal 413, wherein, this voltage magnitude command signal 413 represents the reactive power needing to provide from net side converter 108 to electrical network 110.More specifically, in one embodiment, this q shaft current computing unit 415 can use following formula (13) to calculate q shaft current command signal 417:

Q=V _{mag_potc}*I _q(13),

Wherein, Q is for expecting that the reactive power provided exports, and it can be set by specific standard (such as, E.ON), V _{mag_potc}for the amplitude of the voltage measured by the points of common connection adjacent with electrical network 110, I _qfor q shaft current command value.

Please continue to refer to Figure 11, this d shaft current computing unit 419 is connected with this q shaft current computing unit 415 and this dynamic current threshold computation unit 428.This d shaft current computing unit 419 is configured to use this q shaft current command signal 417 provided by this q shaft current computing unit 415 and the dynamic maximum current threshold signal 436 provided by this dynamic current threshold computation unit 428 to produce d shaft current command signal 421.More specifically, this d shaft current computing unit 419 uses formula below (14) to produce this d shaft current command signal 421:

I _d ²+I _q ²=I _{max_d} ²(14),

Wherein, I _dfor d shaft current command signal, I _qfor q shaft current command signal, I _{max_d}for dynamic maximum current threshold signal.

Please continue to refer to Figure 11, the q shaft current command signal 417 that this voltage difference computing unit 423 is configured at least provide according to the d shaft current command signal 421 provided by this d shaft current computing unit 419 and this q shaft current computing unit 415 calculates d shaft voltage difference signal 425 and q shaft voltage difference signal 427.More specifically, this voltage difference computing unit 423 is configured to use formula below (15) and formula (16) to calculate this d axle and q shaft voltage difference signal:

dV _d=I _q*[(X _brg+X _vir)*j] (15),

dV=I _d*[(X _brg+X _vir)*j] (16),

Wherein, dV _dfor d shaft voltage difference signal 425, dV _qfor q shaft voltage difference signal 4427, I _dfor d shaft current command signal, I _qfor q shaft current command signal, X _brgfor electric network impedance 714, X _virfor converter internal driving 712.

In one embodiment, this phase angle restricting signal computing unit 444 is configured at least produce maximal phase parallactic angle restricting signal 446 and minimum phase angle restricting signal 448 according to this d shaft voltage difference signal 425 and q shaft voltage difference signal 427.In one more specifically execution mode, this phase angle restricting signal computing unit 444 is configured to use following formula (17) and formula (18) to calculate this minimum and maximum phase angle restricting signal 446,448:

${\mathrm{\θ}}_{\max }=a\tan \left(\frac{{\mathrm{dV}}_q}{(V_{g_{\mathrm{potc}}}+{\mathrm{dV}}_d)}\right)---\left(17\right),$

${\mathrm{\θ}}_{\min }=-{\mathrm{\θ}}_{\max }=-\mathrm{atar}\left(\frac{{\mathrm{dV}}_q}{(V_{g_{\mathrm{potc}}}+{\mathrm{dV}}_d)}\right)---\left(18\right),$

Wherein, dV _dfor d shaft voltage difference signal 425(as shown in figure 12), dV _qfor q shaft voltage difference signal 427, for the voltage measured by the points of common connection adjacent with electrical network 110.

In one embodiment, this voltage magnitude restricting signal computing unit 452 is configured at least produce maximum voltage amplitude restricting signal 454 and minimum voltage amplitude restricting signal 456 according to this d shaft voltage deviation signal 425, q shaft voltage deviation signal 427 and feedback voltage signal 458.In the specific execution mode of one, this voltage magnitude restricting signal computing unit 452 is configured to use following formula (19), and formula (20) and formula (21) calculate this voltage magnitude restricting signal 454,456:

$V_{\mathrm{mag}\_\mathrm{diff}}=\sqrt{{\mathrm{dV}}^2-{(V_{g\_\mathrm{potc}}*\sin {\mathrm{\θ}}_{\mathrm{real}})}^2}---\left(19\right),$

V _mag_max=V _{g_ootc}*cosθreal+V _mag_diff (20),

$V_{\mathrm{mag}\_\min }=\frac{V_{g\_\mathrm{potc}}+{\mathrm{dV}}_d}{\sin {\mathrm{\θ}}_{\mathrm{real}}}---\left(21\right),$

Wherein, V _{mag_max}for maximum voltage amplitude restricting signal 454, V _{mag_min}for minimum voltage amplitude restricting signal 456, θ _realfor actual phase angle signal, V _{mag_diff}for the amplitude of the voltage difference by virtual impedance 712 and electric network impedance 714.

Please continue to refer to Figure 11, this maximal phase parallactic angle restricting signal 446 and minimum phase angle restricting signal 448 are adjusted according to phase angle adjustment signal 474 by this phase angle restricting signal adjustment unit 476.For example, when DC link 128 runs into overvoltage situation, this phase angle restricting signal adjustment unit 476 can use as formula described in conjunction with Figure 4 (7) and formula (8) adjust this minimum and maximum phase angle restricting signal 446,448 above.Similarly, when DC link 128 runs under voltage situation, this phase angle restricting signal adjustment unit 476 can use as formula described in conjunction with Figure 4 (9) and formula (10) adjust this minimum and maximum phase angle restricting signal 446,448 above.This phase angle restricting signal adjustment unit 476 provides the maximal phase parallactic angle restricting signal 478 of adjustment and the minimum phase angle restricting signal 482 adjusted to voltage command signal limiting unit 484, and is used for limiting phase angle command signal 486 by this voltage command signal limiting unit 484.Similarly, the phase angle command signal 492 of this restriction and the voltage magnitude command signal 494 of restriction can be used for producing net side control signal 242(such as by the signal generation unit 240 shown in Fig. 3, pwm control signal), thus the operation of Controling network side converter 108.

Figure 13 shows that the flow chart of a kind of execution mode controlling the method 1300 that energy conversion system runs.The method 1300 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 performed by computer or processor, each step as shown in the flowchart can be realized.Be appreciated that the medium of computer-readable can comprise volatibility with non-volatile, in any method or technology realize moveable and non-moveable 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, or the memory of other technologies, compact disc read-only memory, digitlization disk storage, or other forms of optical memory, cassette, tape, magnetic disc, or other forms of magnetic storage, and the storage medium that can be used to the predetermined information that stored energy is accessed by instruction execution system of any other form.

In one embodiment, the method 1300 can perform from step 1302, in execution step 1302, obtains the current threshold relevant with the converter device in electrical conversion systems (electrical conversion systems 10,100 such as shown in Fig. 1 and Fig. 2).In one embodiment, this current threshold presets, and it represents the current value flowed out from this converter device of maximum permission.

In step 1304, the method 1300 produces maximal phase parallactic angle restricting signal and minimum phase angle restricting signal according to this current threshold.As described above, can use formula (1), formula (2) and formula (3) calculate minimum and maximum phase angle restricting signal.In some embodiments, this current threshold can have fixing numerical value.In other embodiments, this current threshold also can the vicissitudinous numerical value of tool.For example, this current threshold can have dynamic current threshold value, and it dynamically can be regulated according to current feedback signal, such as, directly regulates according to negative sequence component signal.In other execution mode, the negative sequence component in current feedback signal can be removed, but produce this dynamic current threshold signal by the positive sequence component in current feedback signal.

In some embodiments, in step 1304, the method 1300 can also produce maximum voltage amplitude restricting signal and minimum voltage amplitude restricting signal according to this current threshold.

In some embodiments, the reactive power that this minimum and maximum phase angle restricting signal and minimum and maximum voltage magnitude restricting signal can provide as required exports and produces.For example, when not needing to provide reactive power to electrical network, this minimum and maximum voltage magnitude restricting signal can be configured to have the numerical value equal with line voltage.

In step 1306, the method 1300 at least produces phase angle restriction adjustment signal based on direct voltage command signal and actual feedback d. c. voltage signal.This phase angle restriction adjustment signal has different numerical value according to the voltage condition of this DC link 128.Such as, in one embodiment, when this DC link 128 runs into overvoltage situation, this phase angle restriction adjustment signal can have negative value, and when this DC link 128 runs under voltage situation, the restriction of this phase angle adjust signal can have on the occasion of.It should be noted that in some embodiments, step 1306 described herein can perform and also synchronously can perform with step 1304 before step 1304.

In step 1308, the method 1300 uses this phase angle to limit adjustment signal and adjusts this maximal phase parallactic angle restricting signal and at least one in this minimum phase angle restricting signal.More specifically, formula described above (7) and formula (8) can be used to adjust this minimum and maximum phase angle restricting signal.In other embodiments, can use as formula described in conjunction with Figure 4 (9) and formula (10) adjust this minimum and maximum phase angle restricting signal above.

In step 1312, the maximal phase parallactic angle restricting signal after the method 1300 uses this adjustment and at least one in this minimum phase angle restricting signal are to limit phase angle command signal.In one embodiment, this phase angle command signal can be produced by the phase angle regulation device 210 above described in composition graphs 3.

In step 1314, the method 1300 also uses at least one voltage magnitude restricting signal to limit voltage magnitude command signal.In one embodiment, the voltage magnitude adjuster 220 above described in composition graphs 3 can be used for producing this voltage magnitude signal.

Be understandable that, method 1300 described here can also comprise other steps.Such as, the method 1300 can also use the phase angle command signal of restriction and the voltage magnitude command signal of restriction to produce net side control signal (such as, pwm control signal).

Although describe the present invention in conjunction with specific execution mode, those skilled in the art will appreciate that and can make many amendments and modification to the present invention.Therefore, recognize, the intention of claims is to be encompassed in all such modifications in true spirit of the present invention and scope and modification.

Claims (10)

1. an energy conversion system, is characterized in that: this energy conversion system comprises DC link, converter device and inverter controller; This converter device is connected with this DC link, and this converter device is configured to change the direct current energy that this DC link provides and provide AC energy; This inverter controller is connected with this DC link and this convertor device, this converter controller comprises mixed DC voltage and output current control module, and this mixed DC voltage and output current control module are used for limiting the output current of the AC energy that this converter device provides when this electrical conversion systems runs at least one transient affair and regulating the direct voltage of this DC link; Wherein, this mixed DC voltage and output current control module comprise phase angle regulation device, direct current voltage regulator and demand limiter; This phase angle regulation device is for generation of phase angle command signal; This direct current voltage regulator is used at least producing phase angle based on direct voltage command signal and the actual DC voltage signal relevant to this DC link and limits and adjust signal; This demand limiter is connected with this phase angle regulation device and this direct current voltage regulator, this demand limiter is used at least producing at least one in maximal phase parallactic angle restricting signal and minimum phase angle restricting signal based on the current threshold relevant to this converter device, and this maximal phase parallactic angle restricting signal and this minimum phase angle restricting signal are used for limiting this phase angle command signal; This demand limiter also adjusts at least one in this maximal phase parallactic angle restricting signal and minimum phase angle restricting signal for using this phase angle to limit adjustment signal.

2. energy conversion system as claimed in claim 1, it is characterized in that: this demand limiter be configured to when this actual DC voltage signal be judged as be greater than this direct voltage command signal time, use this phase angle limit adjustment signal increase this minimum phase angle restricting signal.

3. energy conversion system as claimed in claim 1, it is characterized in that: this demand limiter is configured to when this actual DC voltage signal is determined to be smaller than this direct voltage command signal, use this phase angle to limit adjustment signal and reduce this maximal phase parallactic angle restricting signal.

4. energy conversion system as claimed in claim 1, it is characterized in that: this mixed DC voltage and output current control module comprise voltage magnitude adjuster, this voltage magnitude adjuster is for generation of voltage magnitude command signal; This demand limiter is configured at least produce at least one maximum voltage amplitude restricting signal and minimum voltage amplitude restricting signal based on this current threshold, wherein, this maximum voltage amplitude restricting signal and minimum voltage amplitude restricting signal are used for limiting this voltage magnitude command signal.

5. energy conversion system as claimed in claim 4, it is characterized in that: it is equal that this demand limiter is configured to that this maximum voltage amplitude restricting signal and minimum voltage amplitude restricting signal are set to the magnitude of voltage relevant to load, and providing to allow this converter device is that the reactive power of zero is to load substantially.

6. energy conversion system as claimed in claim 1, is characterized in that: this current threshold carries out dynamic adjustments according to the negative-sequence current component of this output current.

7., for controlling the method that energy conversion system runs, this energy conversion system comprises DC link, and converter device and inverter controller, is characterized in that: the method at least comprises the steps:

At least produce at least one in maximal phase parallactic angle restricting signal and minimum phase angle restricting signal based on the current threshold relevant to this converter device;

At least produce phase angle based on direct voltage command signal and the actual DC voltage signal relevant to this DC link to limit and adjust signal;

Use this phase angle to limit adjustment signal and adjust at least one in this maximal phase parallactic angle restricting signal and minimum phase angle restricting signal; And

Use at least one restriction phase angle command signal in this maximal phase parallactic angle restricting signal after this adjustment and this minimum phase angle restricting signal.

8. method as claimed in claim 7, it is characterized in that: wherein, the method also comprises the steps:

When this actual DC voltage signal be judged as be greater than this direct voltage command signal time, use this phase angle limit adjustment signal increase this minimum phase angle restricting signal; And

When this actual DC voltage signal is determined to be smaller than this direct voltage command signal, uses this phase angle to limit adjustment signal and reduce this maximal phase parallactic angle restricting signal.

9. method as claimed in claim 7, is characterized in that: the method also comprises the steps: this current threshold of negative-sequence current component dynamic adjustments according to this output current.

10. a photovoltaic energy conversion system, this photovoltaic energy conversion system is connected with electrical network, it is characterized in that: this photovoltaic energy conversion system comprises DC link, photovoltaic converter and photovoltaic controller; This DC link is configured to receive the direct current energy coming from photovoltaic energy source; This photovoltaic converter is connected with this DC link, this photovoltaic converter is configured to change the direct current energy that this DC link provides and provide active power to this electrical network, this photovoltaic controller is connected with this DC link and this photovoltaic converter, and this photovoltaic controller is configured to: produce phase angle command signal to control the phase angle of the output voltage of this photovoltaic converter; Produce maximal phase parallactic angle restricting signal and minimum phase angle restricting signal for the output current limiting this photovoltaic converter and provide; And at least adjust at least one in this maximal phase parallactic angle restricting signal and minimum phase angle restricting signal based on the voltage difference between direct voltage command signal and the actual DC voltage signal relevant to this DC link, to adjust the numerical value of the active power provided by this photovoltaic converter, controlled to make the direct voltage of this DC link.