CN112467784B - Control method for adaptive virtual synchronous machine of hybrid microgrid converter - Google Patents
Control method for adaptive virtual synchronous machine of hybrid microgrid converter Download PDFInfo
- Publication number
- CN112467784B CN112467784B CN202011295937.8A CN202011295937A CN112467784B CN 112467784 B CN112467784 B CN 112467784B CN 202011295937 A CN202011295937 A CN 202011295937A CN 112467784 B CN112467784 B CN 112467784B
- Authority
- CN
- China
- Prior art keywords
- virtual
- converter
- power
- inertia
- alternating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- 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
- H02J3/24—Arrangements for preventing or reducing oscillations of 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
- H02J5/00—Circuit arrangements for transfer of electric power between ac networks and dc 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
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/10—The dispersed energy generation being of fossil origin, e.g. diesel generators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/28—The renewable source being wind energy
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/40—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation wherein a plurality of decentralised, dispersed or local energy generation technologies are operated simultaneously
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Supply And Distribution Of Alternating Current (AREA)
- Control Of Eletrric Generators (AREA)
Abstract
The invention discloses a control method of a self-adaptive virtual synchronous machine of a hybrid microgrid converter, which adopts self-adaptive virtual moment of inertia J and self-adaptive virtual damping D in a VSG control system to inhibit power fluctuation of the hybrid microgrid AC/DC converter. Further, in order to obtain a rated virtual parameter value range, a small signal model is established for the self-adaptive VSG control system, and a damping ratio and a rated damping coefficient are obtained by analyzing characteristic values of the small signal model and referring to oscillation angular frequency values of the synchronous generator. The invention adopts the self-adaptive virtual moment of inertia J and the self-adaptive virtual damping D in a VSG control system, and provides a method for increasing J and properly reducing D at the angular frequency increasing stage; in the angular frequency reduction phase, J is reduced while D is properly increased. The invention can ensure the response speed of the system and quicken the power to enter a stable state. The double self-adaptive virtual parameters can effectively restrain power fluctuation.
Description
Technical Field
The invention relates to a control method of a self-adaptive virtual synchronous machine of a hybrid micro-grid converter, which adopts double self-adaptive parameters to improve the power adjustment capability of a control system of the virtual synchronous machine of the hybrid micro-grid converter, and analyzes rated virtual parameter values by establishing a small signal model for the control system of the self-adaptive virtual synchronous machine.
Background
The AC/DC hybrid micro-grid consists of an AC sub-grid, a DC sub-grid and an AC/DC interface converter, wherein the AC/DC hybrid micro-grid is an advanced form for the development of future micro-grids, integrates the advantages of the AC micro-grid and the DC sub-grid, enhances the flexibility of accessing various micro-power supplies and loads in various forms into a micro-grid system, and the AC/DC interface converter is used as a power transmission medium of the AC sub-grid and the DC sub-grid, so that the power dynamic balance between the sub-grids is required to be maintained, and the stable operation of the whole micro-grid is required to be ensured. How to realize the stable power transmission of the AC/DC interface converter through a control strategy is a key for guaranteeing the coordinated operation of the AC/DC hybrid micro-grid.
The AC/DC interface converter in the AC/DC hybrid micro-grid generally adopts droop control, and the droop control does not have inertia and damping links and cannot maintain the stability of the converter control system of the distributed power high-permeability hybrid micro-grid. There is a great deal of interest in the industry by mimicking the control strategy of a conventional synchronous generator to provide an AC/DC interface converter with inertia, i.e. a virtual synchronous machine (Virtual Synchronous Generation, VSG) control strategy. However, in conventional VSG control, the virtual parameter is a fixed value, and cannot suppress power oscillation in the ac/dc micro-grid power exchange process.
Disclosure of Invention
The invention aims to provide a control method of a self-adaptive virtual synchronous machine of a hybrid microgrid converter, which adopts self-adaptive virtual moment of inertia J and self-adaptive virtual damping D in a VSG control system to inhibit power fluctuation of the hybrid microgrid AC/DC converter. Further, in order to obtain a rated virtual parameter value range, a small signal model is established for the self-adaptive VSG control system, and a damping ratio and a rated damping coefficient are obtained by analyzing characteristic values of the small signal model and referring to oscillation angular frequency values of the synchronous generator.
The invention is realized by adopting the following technical scheme:
the method for controlling the self-adaptive virtual synchronous machine of the hybrid micro-grid converter is characterized by comprising the following steps of:
1) Establishing an alternating-current side power transmission equation of an alternating-current/direct-current hybrid microgrid AC/DC converter, and simplifying the power transmission equation;
2) According to the active output adjustment quantity of the alternating current sub-network, the active output adjustment quantity of the direct current sub-network is equal to the power adjustment quantity of the AC/DC converter, the instantaneous active change quantity of the hybrid micro-grid is the same, and an active exchange expression of the AC/DC converter is established;
3) Respectively expanding the active output adjustment quantity of the alternating current sub-network and the active output adjustment quantity of the direct current sub-network in the step 2) into a steady-state active change quantity and a dynamic power change quantity;
4) According to the active output adjustment quantity of the alternating current sub-network and the expansion of the active output adjustment quantity of the direct current sub-network in the step 3), simulating a synchronous generator to obtain a motion equation and a reactive adjustment expression of a virtual synchronous machine VSG rotor of the AC/DC hybrid micro-network AC/DC converter;
5) Analyzing the influence of virtual moment of inertia J and virtual damping coefficient D in the motion equation of the VSG rotor of the AC/DC hybrid microgrid AC/DC converter in the step 4) on the power regulation stability performance, and constructing self-adaptive virtual moment of inertia and virtual damping coefficient;
6) To obtain the nominal virtual parameters J in the adaptive virtual inertia and virtual damping coefficient of the step 5) 0 And D 0 Performing first-order second-order derivation on active power of the alternating-current side of the alternating-current/direct-current hybrid microgrid AC/DC converter in the step 1) within a value range;
7) Introducing the first-order and second-order derivatives of active power at the alternating-current side of the converter obtained in the step 6) and the expansion of the active output adjustment quantity of the alternating-current subnetwork in the step 3) into the VSG rotor motion equation of the alternating-current/direct-current hybrid microgrid AC/DC converter in the step 4) to obtain a VSG output power reference value expression;
8) Step 7), the VSG output power reference value establishes a small signal model, performs Law transformation and calculates characteristic roots thereof;
9) Analyzing the VSG output power reference value small signal model and the characteristic root in the step 8) to obtain the natural oscillation rotating speed and damping ratio of the system;
10 Referring to the oscillation frequency of the synchronous generator to obtain a rated virtual inertia value range, determining the damping ratio and the rated damping coefficient in the step 9) by utilizing an optimal second-order system analysis method on the basis of considering the damping coefficient;
11 And (3) setting the self-adaptive virtual inertia and the virtual damping coefficient in the step 5) according to the rated virtual inertia value range and the rated damping coefficient in the step 10), replacing the original virtual inertia and the virtual damping coefficient in the motion equation of the VSG rotor of the AC/DC hybrid microgrid converter in the step 4), and realizing the power stable control of the self-adaptive virtual synchronous machine of the hybrid microgrid converter.
The invention is further improved in that the specific implementation method of the step 1) is as follows: establishing an alternating current-direct current hybrid microgrid AC/DC converter alternating current side power transmission equation:
wherein: r is R f 、X f The resistance value and the inductance value of the filter circuit are; e is the voltage amplitude of an alternating-current side bridge arm of the AC/DC converter, U ac Is the amplitude of the alternating-current side voltage; delta is the power angle; among the internal parameters of the AC/DC converter, R is satisfied f ＜＜X f The ac side power transfer equation is simplified as:
the power angle delta between the alternating-current side bridge arm voltage and the alternating-current side voltage of the converter is very small, and the converter comprises:
active power is expressed as: />
The invention is further improved in that the specific implementation method of the step 2) is as follows: according to the active output adjustment quantity of the alternating current sub-network, the active output adjustment quantity of the direct current sub-network is equal to the power adjustment quantity of the AC/DC converter, the instantaneous active change quantity of the hybrid micro-grid is the same, and an active exchange expression of the AC/DC converter is established: p (P) acref -P ac ＝P dc -P dcref ＝ΔP。
The invention is further improved in that the specific implementation method of the step 3) is as follows: respectively expanding the active output adjustment quantity of the alternating current sub-network and the active output adjustment quantity of the direct current sub-network in the step 2) into a steady-state active change quantity and a dynamic power change quantity; AC micro-gridThe active output adjustment amount of the medium is expressed as:
wherein: k (k) ω The sag adjustment coefficient of the alternating current network is used; k (k) ω (ω-ω 0 ) Is steady state active variation;
the method comprises the steps that instantaneous active power absorbed or emitted by virtual rotor inertia is provided for an inertia link of alternating current frequency in virtual synchronous machine control; the active output adjustment quantity of the direct current micro-grid is expressed as follows: />
Wherein: k (k) udc The droop adjusting coefficient is a direct current network droop adjusting coefficient; u (U) dc The actual value of the DC bus voltage; u (U) dc0 The initial value of the DC bus voltage is set; is the steady-state active power variation quantity,
the charging and discharging power of the direct current capacitor belongs to dynamic power fluctuation.
The invention is further improved in that the specific implementation method of the step 4) is as follows: according to the step 3), the active output adjustment quantity of the alternating current sub-network and the active output adjustment quantity of the direct current sub-network are expanded, a synchronous generator is simulated, and a rotor motion equation of a virtual synchronous machine of the AC/DC hybrid micro-network AC/DC converter is obtained:
wherein: j is virtual moment of inertia; omega is the angular frequency; k (k) udc The direct current sub-network droop adjusting coefficient is adopted; u (U) dc The actual value of the DC bus voltage; u (U) dc0 The initial value of the DC bus voltage is set; c (C) dc Is a direct current capacitance value; the AC/DC converter control of the AC/DC hybrid microgrid also has excitation regulation inertia, and the reactive regulation expression is: />
Wherein: u is the virtual internal potential of VSG; u (U) 0 Is a rated voltage effective value; Δu is the deviation between the virtual internal potential and the rated voltage; k (k) q Is a reactive power adjustment coefficient; q (Q) e The actual output value of the reactive power is; q (Q) ref Is a reactive power reference value.
The invention is further improved in that the specific implementation method of the step 5) is as follows: analyzing the virtual moment of inertia J and the virtual damping coefficient D in the motion equation of the VSG rotor of the AC/DC hybrid microgrid AC/DC converter in the step 4), and increasing J while properly reducing D in the angular frequency increasing stage; in the angular frequency reduction stage, J is reduced while D is appropriately increased; the adaptive virtual inertia and virtual damping coefficients are expressed as:
wherein: j (J) 0 And D 0 The rated virtual moment of inertia and the rated virtual damping coefficient are adopted; k (k) j And (3) representing the capacity of the virtual moment of inertia to follow the frequency deviation adjustment for the virtual moment of inertia adjustment coefficient.
The invention is further improved in that the specific implementation method of the step 6) is as follows: to obtain the nominal virtual parameters J in the adaptive virtual inertia and virtual damping coefficient of the step 5) 0 And D 0 The value range is obtained by carrying out first-order and second-order derivation on the active power of the alternating current side of the alternating current/direct current hybrid microgrid AC/DC converter in the step 1):
the invention is further improved in that the specific implementation method of the step 7) is as follows: carrying out expansion of the first-order and second-order derivatives of active power at the alternating-current side of the converter obtained in the step 6) and the active output adjustment quantity of the alternating-current subnetwork in the step 3) into a motion equation of a VSG rotor of the alternating-current/direct-current hybrid microgrid AC/DC converter in the step 4), so as to obtain a VSG output power reference value expression:
the invention is further improved in that the specific implementation method of the step 8) is as follows: establishing a small signal model according to the VSG output power reference value in the step 7) and carrying out Laplace transformation:
and calculating the characteristic root:
the invention is further improved in that the specific implementation method of the step 9) is as follows: analyzing the VSG output power reference value small signal model and the characteristic roots in the step 8), wherein in order to ensure the stability of a control system, the two characteristic roots are positioned at the left half part of a complex plane, and the virtual inertia J is kept to be more than or equal to 0; in the power oscillation process, the VSG output power response characteristic is equivalent to a typical second-order transfer function, and the natural oscillation angular frequency and damping ratio of the system are obtained according to the characteristic root expression:
the specific implementation method of the step 10) is as follows: reference synchronous generator oscillation frequency: 0.628 rad/s.ltoreq.ω S Less than or equal to 15.7rad/s, and obtaining a rated virtual inertial measurement value range:
in an AC/DC hybrid micro-grid AC/DC converter self-adaptive VSG control system, in order to obtain a faster response speed and a smaller overshoot, on the basis of considering a damping coefficient, an optimal second-order system analysis method is utilized to determine the damping ratio and the rated damping coefficient in the step 9):
the specific implementation method of the step 11) is as follows: and setting the self-adaptive virtual inertia and the virtual damping coefficient in the step 5) according to the rated virtual inertia value range and the rated damping coefficient in the step 10), replacing the original virtual inertia and the virtual damping coefficient in the motion equation of the VSG rotor of the AC/DC hybrid microgrid converter in the step 4), and realizing the power stable control of the self-adaptive virtual synchronous machine of the hybrid microgrid converter.
Compared with the prior art, the invention has at least the following beneficial technical effects:
1. the invention adopts the self-adaptive virtual moment of inertia J and the self-adaptive virtual damping D in a VSG control system, and provides a method for increasing J and properly reducing D at the angular frequency increasing stage; in the angular frequency reduction phase, J is reduced while D is properly increased. The scheme can ensure the response speed of the system and quicken the power from entering the stable state. The double self-adaptive virtual parameters can effectively inhibit power fluctuation;
2. according to the invention, a small signal model is established for the self-adaptive VSG control system, the value range of the oscillation angle frequency of the synchronous generator is referenced, and rated virtual parameters are analyzed to obtain the damping ratio and rated damping coefficient suitable for the VSG control system of the AC/DC hybrid microgrid AC/DC converter.
Drawings
Fig. 1 is a topological structure diagram of an ac/dc hybrid micro-grid;
FIG. 2 is a circuit topology diagram of an AC/DC converter;
fig. 3 is a control block diagram of a hybrid microgrid AC/DC converter VSG;
FIG. 4 is a plot of VSG active versus virtual angular frequency;
fig. 5 is a block diagram of hybrid microgrid AC/DC converter adaptive VSG control;
FIG. 6 is a diagram of a hybrid microgrid simulation model;
FIG. 7 is a graph of active power dynamic versus simulated waveforms for a rectified AC/DC converter;
FIG. 8 is a graph of adaptive virtual parameter variation in a rectified AC/DC converter, wherein FIG. 8 (a) is adaptive virtual inertia and FIG. 8 (b) is adaptive damping coefficient;
FIG. 9 is a graph of active power dynamic versus simulated waveforms for an AC/DC converter in an inverter state;
fig. 10 is a graph showing a change in adaptive virtual parameters in an inverter state of an AC/DC converter, wherein fig. 10 (a) shows an adaptive virtual inertia, and fig. 10 (b) shows an adaptive damping coefficient.
Detailed Description
The technical scheme of the invention is further described in detail through the attached drawings.
As shown in fig. 1, the AC subnetwork and the DC subnetwork are connected by one or more AC/DC converters, and the AC/DC hybrid subnetwork is connected to the distribution network through a power transformer, and the subnetwork topology can be applied to a distributed power supply and a situation with concentrated load.
As shown in fig. 2; r is R f 、L f 、C f The resistor, the inductor and the capacitor are filter circuits; e, e abc Is the alternating current side bridge arm voltage of the converter; u (u) abc 、i abc Is AC side voltage and current; z is Z ac Is the line impedance.
The AC/DC converter AC side power transfer equation can be expressed as:
in the formula (1): r is R f 、X f The resistance value and the inductance value of the filter circuit are; e is the voltage amplitude of an alternating-current side bridge arm of the AC/DC converter, U ac Is the amplitude of the alternating-current side voltage; delta is the power angle. Among the internal parameters of the AC/DC converter, R is generally satisfied f ＜＜X f Then formula (1) can be simplified as:
in the active expression of formula (2), the power angle δ between the ac side arm voltage and the ac side voltage of the inverter is small, and there are:
active power can in turn be expressed as:
as shown in fig. 3, according to the AC subnet active power adjustment amount, the DC subnet active power adjustment amount is equal to the AC/DC converter power adjustment amount, the instantaneous active change amount of the hybrid micro-grid is the same, namely:
P acref -P ac ＝P dc -P dcref ＝ΔP (4)
the active power adjustment in the ac microgrid can be expressed as:
in formula (5): k (k) ω The sag adjustment coefficient of the alternating current network is used; k (k) ω (ω-ω 0 ) Is steady state active change.
And an inertia link is provided for the alternating current frequency in the control of the virtual synchronous machine for absorbing or emitting the instantaneous active power of the virtual rotor inertia.
The active output adjustment amount in the direct current micro-grid can be expressed as:
in formula (6): k (k) udc The droop adjusting coefficient is a direct current network droop adjusting coefficient; u (U) dc The actual value of the DC bus voltage; u (U) dc0 The initial value of the DC bus voltage. k (k) udc (U dc -U dc0 ) Is the steady-state active power variation quantity,
the charging and discharging power of the direct current capacitor belongs to dynamic power fluctuation.
The AC/DC hybrid microgrid AC/DC converter control system realizes converter VSG control by simulating the characteristics of a synchronous generator, and a rotor motion equation is as follows:
in the formula (7): j is virtual moment of inertia; omega is the angular frequency; k (k) udc The direct current sub-network droop adjusting coefficient is adopted; u (U) dc The actual value of the DC bus voltage; u (U) dc0 The initial value of the DC bus voltage is set; c (C) dc Is a direct current capacitance value; the AC/DC converter control of the AC/DC hybrid microgrid also has excitation regulation inertia, and the reactive regulation expression is:
in formula (8): u is the virtual internal potential of VSG; u (U) 0 Is a rated voltage effective value; Δu is the deviation between the virtual internal potential and the rated voltage; k (k) q Is a reactive power adjustment coefficient; q (Q) e The actual output value of the reactive power is; q (Q) ref Is a reactive power reference value.
As shown in fig. 4, the value of J is too small, the system response time can be reduced but the lack of inertial characteristics can not inhibit the power oscillation; the J-select is too large and the system can suppress power fluctuations but increase response time. Similarly, the virtual damping coefficient D is selected to affect the power oscillation suppression performance. When power oscillation occurs, the angular frequency increases by a period omega>ω 0 The phase a dω/dt is smaller than 0, the phase D dω/dt is larger than 0, the virtual moment of inertia J needs to be increased to restrain the increase of the angular frequency in the angular frequency increasing phase so as to prevent the excessive increase of ω and thus larger overshoot, and the increase of the virtual moment of inertia can lead to the slow down of the response speed of the system, so that the virtual damping coefficient D needs to be properly reduced in the phase to improve the response speed of the system.
Angular frequency reduction phase omega<ω 0 The D omega/dt of the c phase is smaller than 0, D omega/dt of the b phase is larger than 0, the virtual moment of inertia J needs to be reduced to enable the power to be restored to a stable value as soon as possible, and the virtual damping coefficient D can be increased at the same time to further accelerate the frequency attenuation rate, so that the power is faster and more stable.
As shown in fig. 5, the present invention proposes a method of increasing J while appropriately decreasing D in the angular frequency increasing stage; in the angular frequency reduction phase, J is reduced while D is properly increased. The scheme can ensure the response speed of the system and quicken the power from entering the stable state. The adaptive virtual inertia and virtual damping coefficient can be expressed as:
in the formula (9): j (J) 0 And D 0 The rated virtual moment of inertia and the rated virtual damping coefficient are adopted; k (k) j And (3) representing the capacity of the virtual moment of inertia to follow the frequency deviation adjustment for the virtual moment of inertia adjustment coefficient.
To obtain rated virtual parameter J 0 And D 0 And a small signal model needs to be established in the value range. The first-order and second-order derivatives of the active power of the formula (3) are as follows:
bringing formulas (10) and (5) into VSG rotor motion equation (7) yields:
the small signal model is built and Law transformation is carried out to obtain the small signal model:
the characteristic root is as follows:
in order to ensure the stability of the control system, two characteristic roots are required to be positioned at the left half part of the complex plane, and because the damping coefficient D of the virtual synchronous machine is constant positive, in order to ensure the real part of the characteristic roots to be negative, the virtual inertia J is required to be kept to be more than or equal to 0. In the power oscillation process, the VSG output power response characteristic can be equivalent to a typical second-order transfer function, and the natural oscillation angular frequency and damping ratio of the system can be obtained according to the characteristic root expression:
and referring to the range of oscillation angular frequency values of the synchronous generator: 0.628 rad/s.ltoreq.ω S And less than or equal to 15.7rad/s, the rated virtual inertia is as follows:
in an AC/DC hybrid micro-grid AC/DC converter self-adaptive VSG control system, in order to obtain a faster response speed and a smaller overshoot, an optimal second-order system analysis method is utilized on the basis of considering a damping coefficient, and a damping ratio and a rated damping coefficient are taken as follows:
as shown in fig. 6, in order to verify the effectiveness of the VSG control strategy based on the dual adaptive virtual parameters, an AC/DC hybrid microgrid AC/DC converter simulation model is built on a Matlab/Simulink platform, and simulation parameters are shown in table 1.
Table 1 simulation parameters
In order to verify that the double-adaptive parameter VSG control based on the power transmission principle can effectively inhibit power fluctuation, two simulation working conditions are set: 1) And (3) rectifying the AC/DC converter, wherein the load of the direct current micro-grid is increased by 40kW at the moment of 0.5s, and the load of the direct current micro-grid is cut off by 40kW at the moment of 2 s. 2) The AC/DC converter is operated in an inversion mode, the load of the AC micro-grid is increased by 40kW at the moment of 0.5s, and the load of the AC micro-grid is cut off by 40kW at the moment of 2 s.
As shown in fig. 7, the AC/DC converter works in the arrangement mode, the load of the direct current micro-grid is increased by 40kW at the moment of 0.5s, the alternating current micro-grid and the direct current micro-grid respectively bear the load increment of 20kW, the AC/DC converter flows through-20 kW of active power, the response power obtained by adopting the conventional VSG control fluctuates downwards in a large range, the fluctuation range is larger, the power oscillation is serious, and the internal equipment of the micro-grid is very easy to be off-grid. The response power waveform fluctuation obtained by adopting the double-self-adaptive virtual parameter VSG control provided by the invention is greatly reduced, the fluctuation is well controlled, the power target value can be more quickly stabilized, and the power oscillation problem is solved. At the moment of 2s, 40kW of load is cut off, the virtual synchronous machine responds to load change, output power rises, response power obtained by adopting conventional VSG control fluctuates upwards in a large range, peak value is high, power oscillation is serious, response output power waveform obtained by adopting the double-self-adaptive virtual parameter VSG control is smoother, the output power waveform is almost free from overshoot, the output power is quickly stabilized to target power, power oscillation is approaching to 0, adjusting time is further shortened, and the method is more suitable for a hybrid micro-grid AC/DC converter power control system.
As shown in fig. 8, when the hybrid micro-grid AC/DC converter works in the arrangement mode, the adaptive virtual inertia J can be adaptively adjusted along with the power conversion of the AC/DC converter, the power fluctuation deviation is increased, and J is correspondingly increased; the power fluctuation deviation is reduced, and J is correspondingly reduced. The self-adaptive virtual inertia adjustment has continuous smooth characteristic, and can reduce power oscillation in the power adjustment process of the AC/DC converter. The self-adaptive damping coefficient D can be adaptively adjusted along with the power conversion of the AC/DC converter, the power fluctuation deviation is increased, and D is correspondingly increased; the power fluctuation deviation is reduced and D is correspondingly reduced. The adaptive damping coefficient adjustment also has a continuous smooth characteristic.
As shown in fig. 9, the AC/DC converter works in the inversion mode, at the moment of 0.5s, the power is transmitted from the DC side to the AC side by the AC/DC converter, the load of the AC micro-grid is increased by 40kW, the AC micro-grid and the DC micro-grid respectively bear load increment of 20kW, the AC/DC converter flows through +20kW active power, the output active power of the inversion working state of the AC/DC converter rises, the response power obtained by adopting the conventional VSG control has large-scale upward fluctuation, the peak value is higher, the power oscillation is serious, and the response power waveform fluctuation obtained by adopting the dual-adaptive virtual parameter VSG control provided by the invention is greatly reduced, the peak value is correspondingly reduced, the stability to the power target value can be improved, and the power oscillation problem is solved. At the moment of 2s, 40kW of load is cut off, the response power obtained by adopting the conventional VSG control has large-scale downward fluctuation, the power oscillation is serious, the equipment is very easy to be off-line, the response output power waveform obtained by adopting the double-self-adaptive virtual parameter virtual synchronous machine control is smoother, the output power waveform is almost free from overshoot, the power oscillation is quickly stabilized to the target power, and the power oscillation is approaching to 0.
As shown in fig. 10, the adaptive virtual inertia J provided by the invention can be adaptively adjusted by power conversion of the AC/DC converter, so that the power fluctuation deviation is increased, and J is correspondingly increased; the power fluctuation deviation is reduced, and J is correspondingly reduced. The self-adaptive virtual inertia adjustment has continuous smooth characteristic, can reduce the power oscillation problem in the AC/DC converter power adjustment process of the AC/DC hybrid micro-grid, quickens the power stabilization to the target value, and effectively improves the transient stability performance of the hybrid micro-grid. The self-adaptive damping coefficient D can be adaptively adjusted along with the power conversion of the AC/DC converter, the power fluctuation deviation is increased, and D is correspondingly increased; the power fluctuation deviation is reduced and D is correspondingly reduced. The self-adaptive damping coefficient adjustment has continuous smooth characteristic, and can meet the requirement of smaller active power overshoot.
The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and any simple modification, variation and equivalent structural changes made to the above embodiment according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.
Claims (10)
1. The method for controlling the self-adaptive virtual synchronous machine of the hybrid micro-grid converter is characterized by comprising the following steps of:
1) Establishing an alternating-current side power transmission equation of an alternating-current/direct-current hybrid microgrid AC/DC converter, and simplifying the power transmission equation;
2) According to the active output adjustment quantity of the alternating current sub-network, the active output adjustment quantity of the direct current sub-network is equal to the power adjustment quantity of the AC/DC converter, the instantaneous active change quantity of the hybrid micro-grid is the same, and an active exchange expression of the AC/DC converter is established;
3) Respectively expanding the active output adjustment quantity of the alternating current sub-network and the active output adjustment quantity of the direct current sub-network in the step 2) into a steady-state active change quantity and a dynamic power change quantity;
4) According to the active output adjustment quantity of the alternating current sub-network and the expansion of the active output adjustment quantity of the direct current sub-network in the step 3), simulating a synchronous generator to obtain a virtual synchronous machine VSG rotor motion equation and a reactive adjustment expression of the alternating current-direct current hybrid micro-grid AC/DC converter;
5) Analyzing the influence of virtual moment of inertia J and virtual damping coefficient D in the motion equation of the AC/DC hybrid microgrid AC/DC converter VSG rotor on the power regulation stability performance, and constructing self-adaptive virtual moment of inertia and virtual damping coefficient;
6) To obtain the nominal virtual parameters J in the adaptive virtual inertia and virtual damping coefficient of the step 5) 0 And D 0 Performing first-order second-order derivation on active power of the alternating-current side of the alternating-current/direct-current hybrid microgrid AC/DC converter in the step 1) within a value range;
7) Carrying out expansion of the first-order and second-order derivatives of active power on the alternating-current side of the converter obtained in the step 6) and the active output adjustment quantity of the alternating-current subnetwork in the step 3) into the motion equation of the VSG rotor of the alternating-current/direct-current hybrid microgrid AC/DC converter in the step 4) to obtain a VSG output power reference value expression;
8) Step 7), the VSG output power reference value establishes a small signal model, performs Law transformation and calculates characteristic roots thereof;
9) Analyzing the VSG output power reference value small signal model and the characteristic root in the step 8) to obtain the natural oscillation rotating speed and damping ratio of the system;
10 Referring to the oscillation frequency of the synchronous generator to obtain a rated virtual inertia value range, determining the damping ratio and the rated damping coefficient in the step 9) by utilizing an optimal second-order system analysis method on the basis of considering the damping coefficient;
11 And (3) setting the self-adaptive virtual inertia and the virtual damping coefficient in the step 5) according to the rated virtual inertia value range and the rated damping coefficient in the step 10), replacing the original virtual inertia and the virtual damping coefficient in the motion equation of the VSG rotor of the AC/DC hybrid microgrid converter in the step 4), and realizing the power stable control of the self-adaptive virtual synchronous machine of the hybrid microgrid converter.
2. The method for controlling the adaptive virtual synchronous machine of the hybrid micro-grid converter according to claim 1, wherein the specific implementation method of the step 1) is as follows: establishing an alternating current-direct current hybrid microgrid AC/DC converter alternating current side power transmission equation:
wherein: r is R f 、X f The resistance value and the inductance value of the filter circuit are; e is the voltage amplitude of an alternating-current side bridge arm of the AC/DC converter, U ac Is the amplitude of the alternating-current side voltage; delta is the power angle; among the internal parameters of the AC/DC converter, R is satisfied f ＜＜X f The ac side power transfer equation is simplified as:
the power angle delta between the alternating-current side bridge arm voltage and the alternating-current side voltage of the converter is very small, and the converter comprises:
active power is expressed as: />
3. The method for controlling the adaptive virtual synchronous machine of the hybrid micro-grid converter according to claim 2, wherein the specific implementation method of the step 2) is as follows: according to the active output adjustment quantity of the alternating current sub-network and the active of the direct current sub-networkThe output adjustment quantity is equal to the power adjustment quantity of the AC/DC converter, the instantaneous active change quantity of the hybrid micro-grid is the same, and an active exchange expression of the AC/DC converter is established: p (P) acref -P ac ＝P dc -P dcref ＝ΔP。
4. The method for controlling the adaptive virtual synchronous machine of the hybrid micro-grid converter according to claim 3, wherein the specific implementation method of the step 3) is as follows: respectively expanding the active output adjustment quantity of the alternating current sub-network and the active output adjustment quantity of the direct current sub-network in the step 2) into a steady-state active change quantity and a dynamic power change quantity; the active output adjustment amount in the ac subnetwork is expressed as:
wherein: k (k) ω The sag adjustment coefficient of the alternating current network is used; k (k) ω (ω-ω 0 ) Is steady state active variation;
the method comprises the steps that instantaneous active power absorbed or emitted by virtual rotor inertia is provided for an inertia link of alternating current frequency in virtual synchronous machine control; the active output adjustment quantity of the direct current sub-network is expressed as: />
Wherein: k (k) udc The droop adjusting coefficient is a direct current network droop adjusting coefficient; u (U) dc The actual value of the DC bus voltage; u (U) dc0 The initial value of the DC bus voltage is set;
the charging and discharging power of the direct current capacitor belongs to dynamic power fluctuation.
5. The method for controlling the adaptive virtual synchronous machine of the hybrid micro-grid converter according to claim 4, wherein the specific implementation method of the step 4) is as follows:according to the step 3), the active output adjustment quantity of the alternating current sub-network and the active output adjustment quantity of the direct current sub-network are expanded, a synchronous generator is simulated, and a rotor motion equation of the virtual synchronous machine of the alternating current-direct current hybrid micro-grid AC/DC converter is obtained:
wherein: j is virtual moment of inertia; omega is the angular frequency; k (k) udc The direct current sub-network droop adjusting coefficient is adopted; u (U) dc The actual value of the DC bus voltage; u (U) dc0 The initial value of the DC bus voltage is set; c (C) dc Is a direct current capacitance value; the AC/DC converter control of the AC/DC hybrid microgrid also has excitation regulation inertia, and the reactive regulation expression is: />
Wherein: u is the virtual internal potential of VSG; u (U) 0 Is a rated voltage effective value; Δu is the deviation between the virtual internal potential and the rated voltage; k (k) q Is a reactive power adjustment coefficient; q (Q) e The actual output value of the reactive power is; q (Q) ref Is a reactive power reference value.
6. The method for controlling the adaptive virtual synchronous machine of the hybrid micro-grid converter according to claim 5, wherein the specific implementation method of the step 5) is as follows: analyzing the virtual moment of inertia J and the virtual damping coefficient D in the motion equation of the VSG rotor of the AC/DC hybrid microgrid AC/DC converter in the step 4), and increasing J while properly reducing D in the angular frequency increasing stage; in the angular frequency reduction stage, J is reduced while D is appropriately increased; the adaptive virtual inertia and virtual damping coefficients are expressed as:
wherein: j (J) 0 And D 0 The rated virtual moment of inertia and the rated virtual damping coefficient are adopted; k (k) j For the virtual inertia adjustment coefficient, the virtual moment of inertia is represented to follow the frequency deviationPoor ability to adjust.
7. The method for controlling the adaptive virtual synchronous machine of the hybrid micro-grid converter according to claim 6, wherein the specific implementation method of the step 6) is as follows: to obtain the nominal virtual parameters J in the adaptive virtual inertia and virtual damping coefficient of the step 5) 0 And D 0 The value range is obtained by carrying out first-order and second-order derivation on the active power of the alternating current side of the alternating current/direct current hybrid microgrid AC/DC converter in the step 1):
8. the method for controlling the adaptive virtual synchronous machine of the hybrid micro-grid converter according to claim 7, wherein the specific implementation method of the step 7) is as follows: carrying out expansion of the first-order and second-order derivatives of active power at the alternating-current side of the converter obtained in the step 6) and the active output adjustment quantity of the alternating-current subnetwork in the step 3) into the motion equation of the VSG rotor of the alternating-current-direct-current hybrid microgrid AC/DC converter in the step 4), so as to obtain a VSG output power reference value expression:
9. the method for controlling the adaptive virtual synchronous machine of the hybrid micro-grid converter according to claim 8, wherein the specific implementation method of the step 8) is as follows: establishing a small signal model according to the VSG output power reference value in the step 7) and carrying out Laplace transformation:
and calculating the characteristic root: />
10. A hybrid microgrid inverter adaptive virtual common according to claim 9The control method of the walking machine is characterized in that the specific implementation method of the step 9) is as follows: analyzing the VSG output power reference value small signal model and the characteristic roots in the step 8), wherein in order to ensure the stability of a control system, the two characteristic roots are positioned at the left half part of a complex plane, and the virtual inertia J is kept to be more than or equal to 0; in the power oscillation process, the VSG output power response characteristic is equivalent to a typical second-order transfer function, and the natural oscillation angular frequency and damping ratio of the system are obtained according to the characteristic root expression:
the specific implementation method of the step 10) is as follows: reference synchronous generator oscillation frequency: 0.628 rad/s.ltoreq.ω S Less than or equal to 15.7rad/s, and obtaining a rated virtual inertial measurement value range:
in an AC/DC hybrid micro-grid AC/DC converter self-adaptive VSG control system, in order to obtain a faster response speed and a smaller overshoot, on the basis of considering a damping coefficient, an optimal second-order system analysis method is utilized to determine the damping ratio and the rated damping coefficient in the step 9): />
The specific implementation method of the step 11) is as follows: and setting the self-adaptive virtual inertia and the virtual damping coefficient in the step 5) according to the rated virtual inertia value range and the rated damping coefficient in the step 10), replacing the original virtual inertia and the virtual damping coefficient in the motion equation of the VSG rotor of the AC/DC hybrid microgrid converter in the step 4), and realizing the power stable control of the self-adaptive virtual synchronous machine of the hybrid microgrid converter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011295937.8A CN112467784B (en) | 2020-11-18 | 2020-11-18 | Control method for adaptive virtual synchronous machine of hybrid microgrid converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011295937.8A CN112467784B (en) | 2020-11-18 | 2020-11-18 | Control method for adaptive virtual synchronous machine of hybrid microgrid converter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112467784A CN112467784A (en) | 2021-03-09 |
| CN112467784B true CN112467784B (en) | 2023-06-27 |
Family
ID=74837205
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011295937.8A Active CN112467784B (en) | 2020-11-18 | 2020-11-18 | Control method for adaptive virtual synchronous machine of hybrid microgrid converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112467784B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113098058B (en) * | 2021-04-06 | 2023-05-02 | 广东电网有限责任公司电力科学研究院 | Self-adaptive optimization control method, device, equipment and medium for moment of inertia |
| CN113346522A (en) * | 2021-06-16 | 2021-09-03 | 国网上海能源互联网研究院有限公司 | Self-synchronous voltage source self-adaptive control method and system based on rotational inertia |
| CN113507143B (en) * | 2021-07-08 | 2022-09-20 | 东北电力大学 | Hybrid microgrid IC self-adaptive control strategy based on improved VSG technology |
| CN113572204A (en) * | 2021-08-18 | 2021-10-29 | 湖南经研电力设计有限公司 | Self-adaptive control method of virtual synchronous machine |
| CN114221394B (en) * | 2021-11-25 | 2024-04-05 | 浙江大学 | Energy storage system-based self-adaptive virtual synchronous machine control method |
| CN115085242B (en) * | 2022-08-24 | 2022-11-29 | 西安热工研究院有限公司 | Hybrid energy storage VSG self-adaptive virtual damping parameter setting method |
| CN116231679A (en) * | 2022-11-25 | 2023-06-06 | 国网上海市电力公司 | Self-adaptive virtual synchronous machine control method based on deep reinforcement learning |
| CN116632866B (en) * | 2023-07-25 | 2023-12-01 | 西安热工研究院有限公司 | Hybrid energy storage self-adaptive inertia VSG control method for liquid flow super-capacity lithium battery |
| CN117691648B (en) * | 2024-02-04 | 2024-04-26 | 国网浙江省电力有限公司经济技术研究院 | Control method, system, equipment and storage medium of network-structured energy storage converter |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109586269A (en) * | 2018-11-12 | 2019-04-05 | 国网新疆电力有限公司经济技术研究院 | Consider the direct-current grid virtual inertia control method and system of parameter self-optimization |
| CN110474347A (en) * | 2019-08-09 | 2019-11-19 | 上海电机学院 | A kind of two-parameter self-adaptation control method of virtual synchronous generator |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110112769B (en) * | 2019-04-16 | 2023-03-31 | 西安理工大学 | Output feedback self-adaptive control method for virtual synchronous machine |
-
2020
- 2020-11-18 CN CN202011295937.8A patent/CN112467784B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109586269A (en) * | 2018-11-12 | 2019-04-05 | 国网新疆电力有限公司经济技术研究院 | Consider the direct-current grid virtual inertia control method and system of parameter self-optimization |
| CN110474347A (en) * | 2019-08-09 | 2019-11-19 | 上海电机学院 | A kind of two-parameter self-adaptation control method of virtual synchronous generator |
Non-Patent Citations (2)
| Title |
|---|
| A Self-Adaptive Inertia and Damping Combination Control of VSG to Support Frequency Stability;D. Li, Q. Zhu, S. Lin and X. Y. Bian;《IEEE Transactions on Energy Conversion》;20170331;第397-398页 * |
| 考虑参数自适应的直流微电网DC/DC变换器虚拟惯性控制策略研究;曹新慧 等;《高电压技术》;20200430;第1281-1290页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112467784A (en) | 2021-03-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112467784B (en) | Control method for adaptive virtual synchronous machine of hybrid microgrid converter | |
| CN106410849B (en) | Microgrid inverter balance control method based on virtual synchronous generator | |
| CN108832657B (en) | Control method for virtual synchronous motor of alternating current-direct current hybrid microgrid bidirectional power converter | |
| WO2022077847A1 (en) | Virtual synchronous machine control method for hybrid microgrid mmc interconnected converter | |
| CN109586269B (en) | Direct-current micro-grid virtual inertia control method and system considering parameter self-optimization | |
| CN110198055B (en) | Micro-grid bidirectional converter control and stability analysis method based on virtual synchronous machine | |
| CN108649780A (en) | A kind of LCL filter parameter optimization method considering light current inverter stability off the net | |
| CN112467789B (en) | Hybrid microgrid virtual synchronous machine control method based on power transmission principle | |
| CN105552948B (en) | A kind of power grid frequency modulation method based on flexible HVDC transmission system | |
| CN112467790B (en) | Method for inhibiting power oscillation of virtual synchronizer of MMC interconnection converter | |
| CN109980908B (en) | Method for suppressing multi-inverter parallel harmonic under distributed control | |
| CN112467786B (en) | Small signal model analysis method for virtual synchronous machine of hybrid microgrid converter | |
| CN113131521A (en) | Virtual synchronous machine multi-machine parallel stable control and inertia matching method thereof | |
| CN107104447A (en) | Virtual synchronous generator control method based on second order broad sense virtual inertia | |
| CN110365051A (en) | A kind of virtual synchronous motor control method of adaptive instruction filtering inverting | |
| CN115764989A (en) | Virtual synchronous generator system based on network-building type current converter | |
| CN115912405A (en) | Adaptive control strategy for virtual synchronous generator in complex oscillation environment | |
| CN109659978B (en) | Parameter-adaptive virtual synchronous generator control method and control system | |
| CN110336317A (en) | A kind of control method of grid-connected photovoltaic system | |
| CN111525617A (en) | VSG power decoupling control method and system based on excitation regulation | |
| CN116683491A (en) | Inertia control method for new energy micro-grid | |
| Chen et al. | Control strategy of VSC-HVDC inverter supplying power to the isolated grid with induction motor | |
| CN105048459A (en) | Simplified modeling method for calculating low-voltage control inversion-type power symmetric short-circuit fault | |
| Yan et al. | Distributed secondary control of virtual synchronous generator integrated microgrid via extremum seeking | |
| Zhang et al. | Influence of control parameters on synchronization stability of virtual synchronous generator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |