CN117767418A - Method and system for improving transient performance of virtual synchronous machine - Google Patents
Method and system for improving transient performance of virtual synchronous machine Download PDFInfo
- Publication number
- CN117767418A CN117767418A CN202311781085.7A CN202311781085A CN117767418A CN 117767418 A CN117767418 A CN 117767418A CN 202311781085 A CN202311781085 A CN 202311781085A CN 117767418 A CN117767418 A CN 117767418A
- Authority
- CN
- China
- Prior art keywords
- power
- virtual synchronous
- voltage
- active
- reactive power
- 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.)
- Pending
Links
- 230000001360 synchronised effect Effects 0.000 title claims abstract description 75
- 238000000034 method Methods 0.000 title claims abstract description 29
- 230000001052 transient effect Effects 0.000 title claims abstract description 27
- 230000033228 biological regulation Effects 0.000 claims abstract description 16
- 238000004590 computer program Methods 0.000 claims description 20
- 230000006870 function Effects 0.000 claims description 7
- 230000001133 acceleration Effects 0.000 claims description 6
- 238000012887 quadratic function Methods 0.000 claims description 4
- 238000011217 control strategy Methods 0.000 description 8
- 230000003247 decreasing effect Effects 0.000 description 3
- 230000003044 adaptive effect Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- NAWXUBYGYWOOIX-SFHVURJKSA-N (2s)-2-[[4-[2-(2,4-diaminoquinazolin-6-yl)ethyl]benzoyl]amino]-4-methylidenepentanedioic acid Chemical compound C1=CC2=NC(N)=NC(N)=C2C=C1CCC1=CC=C(C(=O)N[C@@H](CC(=C)C(O)=O)C(O)=O)C=C1 NAWXUBYGYWOOIX-SFHVURJKSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000007665 sagging Methods 0.000 description 1
Landscapes
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention discloses a method and a system for improving transient performance of a virtual synchronous machine, which are used for acquiring various performance parameters of the virtual synchronous machine and network side parameters integrated into a power grid; calculating the active power and the reactive power of the virtual synchronous generator, and deducing the relation between the active power and the active angle and the relation between the reactive power and the voltage; based on the relation between active power and active angle and the relation between reactive power and voltage, establishing a constraint condition for stable operation of the virtual synchronous generator, and reducing a given active power reference value and increasing a given reactive power reference value within a regulation and control range meeting the constraint condition when the voltage at the grid-connected point drops; and after the virtual synchronous generator is stabilized, the given value of the reactive power and the given value of the reactive power are restored to the initial values. The transient performance of the inverter controlled by the virtual synchronous generator can be effectively improved, and when a power grid has a short circuit fault, the virtual synchronous generator can be ensured to normally operate all the time, and the power angle stability and the voltage stability are realized.
Description
Technical Field
The invention belongs to the technical field of power systems, and relates to a method and a system for improving transient performance of a virtual synchronous machine.
Background
At present, the trend of the power system towards high-proportion new energy and high-proportion power electronic equipment is that the safety and stability of the power system are also greatly reduced, and the bearing capacity for various faults is also gradually reduced. The virtual synchronous generator (Virtual Synchronous Generator, VSG) is widely applied to renewable energy power generation by virtue of the characteristics of large inertia, quick response and high stability, and is an advanced technology for facilitating the stability of a micro-grid and the integration of renewable energy. However, the research on the VSG is not completely mature, and there are still some transient stability problems, and when the VSG faces to the voltage drop of the power grid, the VSG cannot always keep stable running, so that some potential safety hazards are brought to the power system.
The unbalance of the power reference value and the VSG output power during grid voltage sag is the root cause of the transient stability problem. Excessive power deviation can cause the virtual rotor speed to increase sharply, so that the VSG power angle is increased, the output voltage is reduced, and excessive fault current of the system is caused. Current approaches to improving transient performance of virtual synchronous generators have focused mainly on improving and optimizing their control strategies. Part of the literature adopts an adaptive adjustment method, and performs adaptive adjustment according to the running condition aiming at the deviation of the active-frequency droop coefficient or the active power in the active-frequency control link in the VSG; the output voltage given value of the VSG in the reactive-voltage link is controlled by the literature, a formula of the output voltage at different power angles is given, and the large interference stability of the VSG is improved. The control links are added in the original control strategy, so that the VSG transient stability is improved, and meanwhile, other performances can be adversely affected. Still other documents design different VSG control strategies aiming at different working conditions, when a short circuit fault occurs, the control strategies are automatically switched, and after the fault is recovered, the original strategies are switched back, but the control strategies are suddenly changed to possibly cause larger oscillation to the system, and the system can not be ensured to still stably operate after the switching.
At present, the conventional VSG transient performance improvement method is generally only used for independently adjusting active-frequency or reactive-voltage control links, and the mutual influence between the active-frequency or reactive-voltage control links is not considered, so that the voltage stability and the power angle stability of the system cannot be ensured at the same time. Still other methods require adjustment of the control strategy, which has some impact on the overall characteristics of the VSG, and sagging and inertial links may even fail. Other methods, such as installing reactive compensation devices near the VSG grid connection, can also have some impact on the economics and safety of the grid. It is considered that as the application of virtual synchronous machines in new energy sources becomes wider, it is necessary to take joint control over active power and reactive power during grid voltage sag to ensure transient power angle stability, voltage stability and to suppress over-current.
Disclosure of Invention
The invention aims to solve the problems that in the prior art, active-frequency or reactive-voltage control links are independently adjusted, the mutual influence between control strategies of the active-frequency or reactive-voltage control links is not considered, and the voltage stability and the power angle stability of a system cannot be ensured at the same time.
In order to achieve the purpose, the invention is realized by adopting the following technical scheme:
a method for improving transient performance of a virtual synchronous machine comprises the following steps:
acquiring various performance parameters of the virtual synchronous generator and network side parameters integrated into a power grid;
calculating the active power and the reactive power of the virtual synchronous generator, and deducing the relation between the active power and the active angle and the relation between the reactive power and the voltage;
based on the relation between active power and active angle and the relation between reactive power and voltage, establishing a constraint condition for stable operation of the virtual synchronous generator, and reducing a given active power reference value and increasing a given reactive power reference value within a regulation and control range meeting the constraint condition when the voltage at the grid-connected point drops;
and after the virtual synchronous generator is stabilized, the given value of the reactive power and the given value of the reactive power are restored to the initial values.
The invention further improves that:
the obtaining each performance parameter of the virtual synchronous generator and the network side parameter of the integrated power grid comprises the following steps:
each item of the virtual synchronous generatorThe energy parameter includes rated voltage U 0 Rated active power P and rated reactive power Q, active power command value P ref And reactive power command value Q ref Reactive-voltage sag coefficient k q ；
The network side parameter comprises a power grid voltage U g Line reactance X between grid and virtual synchronous machine grid connection point g 。
The relation between the active power and the active angle is constructed by the formula (1):
wherein: u (U) δ＝0 The value of VSG output voltage U when δ=0 is a constant; from the formula, P e Always less than a sine function, from which P can be drawn e -delta curve;
the relationship between reactive power and voltage is constructed by the formula (2):
wherein: delta U＝0 The value of VSG power angle δ, when u=0, is a constant; from the formula, Q e Always less than a quadratic function, from which Q is drawn e -U-curve.
Calculating the active power of the virtual synchronous generator by the formula (3):
calculating the reactive power of the virtual synchronous generator by the formula (4):
wherein: u is VSG output voltage, delta is VSG power angle.
When the grid-connected point is in voltage drop, reducing the given active power reference value comprises the following steps:
reducing a given active power reference value such that the active power reference value is equal to P e -the delta curve has an intersection point;
and when the virtual synchronous generator operates, the area of the acceleration area is smaller than that of the deceleration area.
The formula for reducing the set value of the active power is as follows:
P′ ref ＝P ref -k 1 (δ b -δ a ) (5)
wherein: p'. ref Is the adjusted active power reference value, k 1 For the active-power angle adjustment factor, delta a Is P when VSG is operating normally ref And P e Intersection point on left side of delta curve, delta b Is P when VSG voltage drops ref And P e Intersection point on left side of delta curve, if there is no intersection point, then
The impulse conditions for the stable operation of the virtual synchronous generator are as follows:
wherein: delta c Is P 'when voltage drop occurs at VSG grid-connected point' ref And P e Intersection point to the right of the delta curve.
Said increasing a given reactive power reference value comprises the steps of:
Q′ ref ＝Q ref +k 2 (U 0 -U) (7)
wherein: q'. ref Is the adjusted active power reference value, k 2 Is a reactive-voltage regulation factor;
the voltage of the virtual synchronous generator satisfies:
0.8U 0 ≤U≤1.2U 0 (8)
the sum of squares of the adjusted power references should not exceed the capacity of the VSG:
(P′ ref ) 2 +(Q′ ref ) 2 ≤S 2 (9)
wherein: s denotes the rated capacity of the VSG.
A virtual synchro-machine transient performance promotion system, comprising:
the parameter acquisition module is used for acquiring various performance parameters of the virtual synchronous generator and network side parameters integrated into a power grid;
the relation deduction module is used for calculating the active power and the reactive power of the virtual synchronous generator and deducing the relation between the active power and the power angle and the relation between the reactive power and the voltage;
the first regulation control module is used for establishing a constraint condition for stable operation of the virtual synchronous generator based on the relation between active power and active angle and the relation between reactive power and voltage, and reducing a given active power reference value and increasing a given reactive power reference value within a regulation and control range meeting the constraint condition when the voltage of the grid-connected point drops;
and the second regulation control module is used for recovering the given value of the reactive power and the given value of the reactive power to the initial value after the virtual synchronous generator is stable.
A terminal device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, the processor implementing the steps of the method according to any one of the claims when the computer program is executed.
A computer readable storage medium storing a computer program which, when executed by a processor, implements the steps of any of the methods of the invention.
Compared with the prior art, the invention has the following beneficial effects:
the invention discloses a method for improving transient performance of a virtual synchronous machine, which comprises the steps of considering the relation between active power and active angle and the relation between reactive power and voltage in the operation of the virtual synchronous machine in the adjusting process, reasonably adjusting the reference values of the active power and the reactive power in a regulation range meeting constraint conditions in combination with the operation condition of the virtual synchronous machine, restricting the output voltage to a given range, and simultaneously ensuring the voltage stability and the active angle stability of VSG.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for improving transient performance of a virtual synchronous machine based on power reference value self-adaptive tuning in an embodiment of the invention;
FIG. 2 shows P before and after voltage drop in an embodiment of the invention e -delta plot;
FIG. 3 shows Q before and after voltage drop in an embodiment of the invention e -U-curve graph.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
In the description of the embodiments of the present invention, it should be noted that, if the terms "upper," "lower," "horizontal," "inner," and the like indicate an azimuth or a positional relationship based on the azimuth or the positional relationship shown in the drawings, or the azimuth or the positional relationship in which the inventive product is conventionally put in use, it is merely for convenience of describing the present invention and simplifying the description, and does not indicate or imply that the apparatus or element to be referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.
Furthermore, the term "horizontal" if present does not mean that the component is required to be absolutely horizontal, but may be slightly inclined. As "horizontal" merely means that its direction is more horizontal than "vertical", and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.
In the description of the embodiments of the present invention, it should also be noted that, unless explicitly specified and limited otherwise, the terms "disposed," "mounted," "connected," and "connected" should be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
The invention is described in further detail below with reference to the attached drawing figures:
referring to fig. 1, the embodiment discloses a method for improving transient performance of a virtual synchronous machine, which comprises the following steps:
step one: acquiring various performance parameters of the virtual synchronous generator (Virtual Synchronous Generator, VSG) and network side parameters of the incorporated power network;
in particular, various performance parameters of the virtual synchronous generator and network side parameters of the incorporated power network are obtained, wherein the performance parameters comprise rated voltage U of VSG output 0 Rated active power P and rated reactive power Q, active power command value P ref And reactive power command value Q ref Reactive-voltage sag coefficient k q ；
The network side parameters include the network voltage U g Line reactance X between grid and virtual synchronous machine grid connection point g 。
Step two: according to the expression of VSG grid-connected output active power and reactive power, deducing the relation between active power and active angle and the relation between reactive power and voltage, and drawing P e Delta and Q e -a U-curve;
specifically, according to the expression of VSG grid-connected output active power and reactive power, deducing the relation between active power and active angle, the relation between reactive power and voltage, and drawing P according to the relation e Delta and Q e -U-curve.
Because the resistance of the circuit is small, the circuit can be ignored, and the active power P is finally obtained e And reactive power Q e The calculation formula of (2) is as follows:
wherein: u is VSG output voltage, delta is VSG power angle.
The reactive power control link of the VSG is as follows:
k q (U ref -U)+(Q ref -Q e )＝0 (10)
wherein: u (U) ref For the voltage command value, the VSG is integrated into the power grid, so that the voltage of the grid connection point is consistent with the voltage of the power grid, and the voltage of the grid connection point is controlled to be U ref ＝U g ；Q ref Is a reactive power command value.
Substituting formula (4) into formula (10) to obtain:
solving the binary once equation to obtain:
on the basis, the derivative of U to delta is calculated:
it can be inferred from this that U is a monotonically decreasing function with respect to δ in the definition domain, that is, U decreases continuously as δ increases, and for equation (3):
wherein: u (U) δ＝0 The value of VSG output voltage U is a constant when δ=0. As can be seen from formula (7), P e Always smaller than a sine function, from which P can be drawn e -delta curve.
Since U is a monotonically decreasing function of δ in the domain, δ decreases continuously as U increases, cos δ increases continuously, and for equation (4) there is:
wherein: delta U＝0 The value of VSG power angle δ is a constant when u=0. From formula (8), Q e Always smaller than a quadratic function, Q can be drawn according to the quadratic function e -U-curve.
Step three, when the voltage drop fault occurs at the VSG grid-connected point, the VSG may not normally operate, so as to enable the active power set value and P e The delta curve has an intersection point, and the VSG can always keep stable operation, and a given active power reference value needs to be reduced;
specifically, when the voltage drop fault occurs at the VSG grid-connected point, the VSG may not normally operate, that is, when the VSG operates in the rated voltage state, the voltage drop fault occurs at P e There must be an operating point on the delta curve, this operating point being P e -intersection of delta curve with given active power reference value. P when VSG grid-connected point occurs voltage drop fault e The delta curve drops substantially, there may be no intersection with a given active power reference value, and even if there is an intersection, stable operation may not be possible.
Further, the active power is given value and P e The delta curve has an intersection point and the VSG can always be operated stably, since if curve P e The fact that delta and the active power reference value have no intersection points indicates that the VSG has no working point and cannot work normally;
the VSG can always keep stable operation because when P e <P ref In order to be able to output a given active power P, VSG ref The rotor is accelerated, the power angle delta is continuously increased under the drive of the accelerating power, and at the moment, the power angle delta is equal to the P e And P ref An acceleration region is formed between the two; conversely, when P e >P ref When VSG is used, the rotor is decelerated, the power angle delta is continuously reduced, and the rotor is at P e And P ref Forming a deceleration zone therebetween. When the area of the acceleration region is largeWhen the area of the deceleration area is larger than the rated angular speed, the VSG outputs an angular speed which is larger than the rated angular speed, and the inverter is unstable; when the area of the acceleration region is smaller than that of the deceleration region, the VSG can maintain stable operation.
Further, lowering a given active power reference may improve the stability of the overall VSG system. The formula for reducing the set value of the active power is as follows:
P′ ref ＝P ref -k 1 (δ b -δ a ) (5)
wherein: p'. ref Is the adjusted active power reference value, k 1 For the active-power angle adjustment factor, delta a Is P when VSG is operating normally ref And P e Intersection point on left side of delta curve, delta b Is P when VSG voltage drops ref And P e Intersection point on left side of delta curve, if there is no intersection point, thenThe formula takes into account the power angle difference requirement for adjustment capability and needs to find the appropriate k 1 A value such that the VSG can be stably operated.
The conditions for stable operation of VSG are:
wherein: delta c Is P 'when voltage drop occurs at VSG grid-connected point' ref And P e The intersection point on the right side of the delta curve, the meaning of the formula is that the area of the acceleration region is smaller than the area of the deceleration region.
Step four, in order to relieve the harm caused by voltage drop faults, a given reactive power reference value is required to be added, and grid-connected point voltage is compensated and regulated;
specifically, a given reactive power reference value is increased, the voltage of a grid-connected point is compensated and adjusted, and a formula for increasing the reactive power given value is as follows:
Q′ ref ＝Q ref +k 2 (U 0 -U) (7)
wherein: q'. ref Is the adjusted active power reference value, k 2 Is the reactive-voltage regulation factor. The formula considers the requirement of the voltage drop degree on reactive power output and needs to find a proper k 2 And (3) supporting the grid-connected point voltage of the VSG.
The voltage of the VSG grid connection point should meet the following conditions:
0.8U 0 ≤U≤1.2U 0 (8)
on this basis, the sum of squares of the adjusted power references should not exceed the capacity of the VSG:
(P′ ref ) 2 +(Q′ ref ) 2 ≤S 2 (9)
wherein: s denotes the rated capacity of the VSG.
And fifthly, immediately recovering the set value of the active power and the reactive power to the initial value after the fault is cleared, and keeping the VSG in normal operation.
Specifically, immediately recovering the set values of the active power and the reactive power to the initial values after the fault is cleared, that is, during the fault that the voltage of the VSG grid-connected point drops, the reference values of the active power and the reactive power are respectively kept to be P' ref And Q' ref And immediately after the fault is cleared, the active power and reactive power reference values are set to be the initial P ref And Q ref The VSG can still normally operate after a period of time has elapsed.
Referring to fig. 2 to 3, in the present embodiment, the rated output voltage of the entire virtual synchronous generator is 220V, the rated active power is 10kW, the rated reactive power is 0kVar, and in the VSG, both the active power and the reactive power reference values are set to the rated values.
Assuming that the system suddenly has short-circuit fault, k under various conditions is obtained according to different degrees (0.2p.u. -0.9p.u.) of voltage drop of VSG grid-connected points 1 、k 2 、P′ ref 、Q′ ref The range of values of (2) is shown in the following table 1:
TABLE 1
It can be deduced from the table that when the voltage drops, the VSG control has a certain stability margin, and if the drop degree is lower, the virtual synchronous machine can still keep normal operation without instability when the drop degree is 0.8pu or 0.9pu, and the reference values of the active power and the reactive power are not changed at the moment. With the voltage drop degree increasing, k 1 The value is increased continuously, k 2 The value is gradually increased and then gradually decreased; the amplitude of the change of the power reference value is continuously increased, the active power reference value is continuously reduced, the reactive power reference value is continuously increased, the output power of the VSG can effectively track the change of the reference value, given active power and reactive power are output, the stability of the power angle and the voltage stability of the VSG are effectively improved, and the stable operation of the power distribution network is ensured.
According to the method disclosed by the embodiment, active-frequency links and reactive-voltage links in the VSG control system are considered, and the reference values of active power and reactive power are reasonably adjusted according to the operation working condition of the VSG, so that the increase of a power angle can be effectively limited when a short circuit fault occurs in the virtual synchronous generator, the output voltage is restrained to a given range, and meanwhile, the voltage stability and the power angle stability of the VSG are ensured. The method is quick and effective, is easy to realize, does not negatively affect links such as primary frequency modulation, primary voltage modulation and inertia because the overall control strategy of the virtual synchronous generator is not changed, and can remarkably improve the transient characteristics of the virtual synchronous generator.
The embodiment also discloses a transient performance improving system of the virtual synchronous machine, comprising:
the parameter acquisition module is used for acquiring various performance parameters of the virtual synchronous generator and network side parameters integrated into a power grid;
the relation deduction module is used for calculating the active power and the reactive power of the virtual synchronous generator and deducing the relation between the active power and the power angle and the relation between the reactive power and the voltage;
the first regulation control module is used for establishing a constraint condition for stable operation of the virtual synchronous generator based on the relation between active power and active angle and the relation between reactive power and voltage, and reducing a given active power reference value and increasing a given reactive power reference value within a regulation and control range meeting the constraint condition when the voltage of the grid-connected point drops;
and the second regulation control module is used for recovering the given value of the reactive power and the given value of the reactive power to the initial value after the virtual synchronous generator is stable.
The invention can effectively improve the transient performance of the inverter controlled by the virtual synchronous generator, ensure that the virtual synchronous generator can always normally operate when a power grid has a short circuit fault, realize stable power angle and stable voltage, and avoid instability.
The embodiment of the invention provides a schematic diagram of terminal equipment. The terminal device of this embodiment includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. The steps of the various method embodiments described above are implemented when the processor executes the computer program. Alternatively, the processor may implement the functions of the modules/units in the above-described device embodiments when executing the computer program.
The computer program may be divided into one or more modules/units, which are stored in the memory and executed by the processor to accomplish the present invention.
The terminal equipment can be computing equipment such as a desktop computer, a notebook computer, a palm computer, a cloud server and the like. The terminal device may include, but is not limited to, a processor, a memory.
The processor may be a central processing unit (CentralProcessingUnit, CPU), but may also be other general purpose processors, digital signal processors (DigitalSignalProcessor, DSP), application specific integrated circuits (ApplicationSpecificIntegratedCircuit, ASIC), off-the-shelf programmable gate arrays (Field-ProgrammableGateArray, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like.
The memory may be used to store the computer program and/or module, and the processor may implement various functions of the terminal device by running or executing the computer program and/or module stored in the memory and invoking data stored in the memory.
The modules/units integrated in the terminal device may be stored in a computer readable storage medium if implemented in the form of software functional units and sold or used as separate products. Based on such understanding, the present invention may implement all or part of the flow of the method of the above embodiment, or may be implemented by a computer program to instruct related hardware, where the computer program may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the computer program may implement the steps of each of the method embodiments described above. Wherein the computer program comprises computer program code which may be in source code form, object code form, executable file or some intermediate form etc. The computer readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer memory, a Read-only memory (ROM), a random access memory (RAM, randomAccessMemory), an electrical carrier signal, a telecommunication signal, a software distribution medium, and so forth. It should be noted that the computer readable medium contains content that can be appropriately scaled according to the requirements of jurisdictions in which such content is subject to legislation and patent practice, such as in certain jurisdictions in which such content is subject to legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunication signals.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The method for improving the transient performance of the virtual synchronous machine is characterized by comprising the following steps of:
acquiring various performance parameters of the virtual synchronous generator and network side parameters integrated into a power grid;
calculating the active power and the reactive power of the virtual synchronous generator, and deducing the relation between the active power and the active angle and the relation between the reactive power and the voltage;
based on the relation between active power and active angle and the relation between reactive power and voltage, establishing a constraint condition for stable operation of the virtual synchronous generator, and reducing a given active power reference value and increasing a given reactive power reference value within a regulation and control range meeting the constraint condition when the voltage at the grid-connected point drops;
and after the virtual synchronous generator is stabilized, the given value of the reactive power and the given value of the reactive power are restored to the initial values.
2. The method for improving transient performance of a virtual synchronous machine according to claim 1, wherein the obtaining each performance parameter of the virtual synchronous generator and a network side parameter incorporated into a power grid comprises:
the performance parameters of the virtual synchronous generator include rated voltage U 0 Rated active power P and rated reactive power Q, active power command value P ref And reactive power command value Q ref Reactive-voltage sag coefficient k q ；
The network side parameter comprises a power grid voltage U g Line reactance X between grid and virtual synchronous machine grid connection point g 。
3. The method for improving transient performance of a virtual synchronous machine according to claim 1, wherein the relation between the active power and the active angle is constructed by the following formula (1):
wherein: u (U) δ＝0 Represents VSG output power when δ=0The value of the pressure U is a constant; from the formula, P e Always less than a sine function, from which P can be drawn e -delta curve;
the relationship between reactive power and voltage is constructed by the formula (2):
wherein: delta U＝0 The value of VSG power angle δ, when u=0, is a constant; from the formula, Q e Always less than a quadratic function, from which Q is drawn e -U-curve.
4. A method for improving transient performance of a virtual synchronous machine according to claim 3,
calculating the active power of the virtual synchronous generator by the formula (3):
calculating the reactive power of the virtual synchronous generator by the formula (4):
wherein: u is VSG output voltage, delta is VSG power angle.
5. The method for improving transient performance of a virtual synchronous machine according to claim 2, wherein when a voltage drop occurs at a grid-connected point, reducing a given active power reference value comprises the steps of:
reducing a given active power reference value such that the active power reference value is equal to P e -the delta curve has an intersection point;
and when the virtual synchronous generator operates, the area of the acceleration area is smaller than that of the deceleration area.
6. The method for improving transient performance of a virtual synchronous machine according to claim 5, wherein the formula for reducing the set value of the active power is:
P r ′ ef ＝P ref -k 1 (δ b -δ a ) (5)
wherein: p (P) r ′ ef Is the adjusted active power reference value, k 1 For the active-power angle adjustment factor, delta a Is P when VSG is operating normally ref And P e Intersection point on left side of delta curve, delta b Is P when VSG voltage drops ref And P e Intersection point on left side of delta curve, if there is no intersection point, then
The impulse conditions for the stable operation of the virtual synchronous generator are as follows:
wherein: delta c Is P when voltage drop occurs at VSG grid-connected point r ′ ef And P e Intersection point to the right of the delta curve.
7. The method for improving transient performance of a virtual synchronous machine according to claim 5, wherein the increasing the given reactive power reference value comprises the steps of:
Q r ′ ef ＝Q ref +k 2 (U 0 -U) (7)
wherein: q (Q) r ′ ef Is the adjusted active power reference value, k 2 Is a reactive-voltage regulation factor;
the voltage of the virtual synchronous generator satisfies:
0.8U 0 ≤U≤1.2U 0 (8) Adjusted power referenceThe sum of squares of the values should not exceed the capacity of the VSG:
(P r ′ ef ) 2 +(Q r ′ ef ) 2 ≤S 2 (9) Wherein: s denotes the rated capacity of the VSG.
8. A virtual synchro-machine transient performance promotion system, comprising:
the parameter acquisition module is used for acquiring various performance parameters of the virtual synchronous generator and network side parameters integrated into a power grid;
the relation deduction module is used for calculating the active power and the reactive power of the virtual synchronous generator and deducing the relation between the active power and the power angle and the relation between the reactive power and the voltage;
the first regulation control module is used for establishing a constraint condition for stable operation of the virtual synchronous generator based on the relation between active power and active angle and the relation between reactive power and voltage, and reducing a given active power reference value and increasing a given reactive power reference value within a regulation and control range meeting the constraint condition when the voltage of the grid-connected point drops;
and the second regulation control module is used for recovering the given value of the reactive power and the given value of the reactive power to the initial value after the virtual synchronous generator is stable.
9. A terminal device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the method according to any of claims 1-7 when the computer program is executed.
10. A computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the steps of the method according to any one of claims 1-7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311781085.7A CN117767418A (en) | 2023-12-21 | 2023-12-21 | Method and system for improving transient performance of virtual synchronous machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311781085.7A CN117767418A (en) | 2023-12-21 | 2023-12-21 | Method and system for improving transient performance of virtual synchronous machine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117767418A true CN117767418A (en) | 2024-03-26 |
Family
ID=90313830
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311781085.7A Pending CN117767418A (en) | 2023-12-21 | 2023-12-21 | Method and system for improving transient performance of virtual synchronous machine |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117767418A (en) |
-
2023
- 2023-12-21 CN CN202311781085.7A patent/CN117767418A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107732956B (en) | Variable-power tracking track two-stage type photovoltaic grid-connected system low-voltage ride-through method | |
| Mohammadpour et al. | Modeling and control of gate-controlled series capacitor interfaced with a DFIG-based wind farm | |
| Wang et al. | VSG-based adaptive droop control for frequency and active power regulation in the MTDC system | |
| CN108429431B (en) | Converter based on virtual synchronous generator and control method thereof | |
| CN110212513B (en) | Flexible virtual capacitor control method for stabilizing voltage fluctuation of direct-current micro-grid bus | |
| CN109672190B (en) | Control method and system for frequency modulation of wind power grid-connected inverter | |
| Wong et al. | A consensus-based adaptive virtual output impedance control scheme for reactive power sharing in radial microgrids | |
| Lyu et al. | Grid forming fast frequency response for PMSG-based wind turbines | |
| CN110311414B (en) | Doubly-fed wind turbine control parameter optimization method and system based on energy stability domain | |
| Tang et al. | Coupling characteristics of DFIG-based WT considering reactive power control and its impact on phase/amplitude transient stability in a rotor speed control timescale | |
| Gao et al. | Grid-following and grid-forming control in power electronic based power systems: A comparative study | |
| CN105356781A (en) | Control method for inhibiting offset of transient virtual power angle curve of drop-controlled inverter | |
| CN114744672A (en) | Low voltage ride through control method and system for two-stage grid-connected photovoltaic system | |
| CN108565897B (en) | Low-voltage crossing locking phase control method and unit, Transient Stability Control method and system | |
| CN113193587B (en) | Sending-out cooperative control method and system for island double-fed wind power plant through high-voltage direct-current transmission | |
| Aghdam et al. | Adaptive virtual inertia synthesis via enhanced dispatchable virtual oscillator controlled grid-tied inverters | |
| CN113659611A (en) | Control method for virtual inertia of virtual synchronous generator in grid-connected mode | |
| CN117767418A (en) | Method and system for improving transient performance of virtual synchronous machine | |
| Basu et al. | Interarea-oscillation damping with dual power oscillation damping controller of a utility-scale wind power plant | |
| Ngom et al. | An improved control for DC-link fluctuation during voltage dip based on DFIG | |
| CN111864783B (en) | Direct-current short-circuit fault ride-through control method and related device | |
| CN111756054B (en) | VSG control method based on cooperative self-adaption of inertia and virtual impedance | |
| Jewel et al. | Design of Double-Integral Sliding Mode Controllers to Mitigate SSR Problems in DFIG-Based Wind Farms Using Fast Power Reaching Laws | |
| Shao et al. | Adaptive damping coefficient control of virtual synchronous generator of microgrid inverter | |
| Ally et al. | Robust PI control of a grid-connected voltage source inverter for virtual inertia response in weak grid conditions |
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 |