CN115207912A - Small signal stability enhancement control strategy for grid-connected converter under weak grid asymmetric voltage drop fault - Google Patents
Small signal stability enhancement control strategy for grid-connected converter under weak grid asymmetric voltage drop fault Download PDFInfo
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- H—ELECTRICITY
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
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Abstract
The invention discloses a small signal stability enhancement control strategy of a grid-connected converter under the asymmetric voltage drop fault of a weak power grid. B) And calculating the dynamic interference of the output dynamics of the phase-locked loop on the negative sequence grid-connected voltage, the output current and the output voltage of the system, and introducing a compensation term on a negative sequence current loop to eliminate the related dynamic interference. According to the invention, on the basis of not increasing hardware equipment, the control strategy of the converter system is redesigned, disturbance caused by a phase-locked loop in a positive sequence current loop and a negative sequence current loop of the grid-connected converter under the asymmetric voltage drop fault is compensated and controlled, the small signal stability of the system during the asymmetric voltage drop fault is enhanced, and the success rate of asymmetric voltage drop fault ride-through is improved.
Description
Technical Field
The invention relates to a grid-connected converter system control method during an asymmetric voltage drop fault, which aims to enhance the small signal stability of a system during the asymmetric voltage drop fault and improve the success rate of asymmetric voltage drop fault ride-through, and belongs to the field of new energy power generation.
Background
With the increasing severity of energy and environmental issues, new energy power generation technology has gained wide attention and great development. Among these, a large number of photovoltaic power plants and wind generators are connected to the grid by means of power electronic converters as interfaces. However, because the power generation equipment is usually far away from the load center, the transmission lines of some new energy grid-connected systems are relatively weak, which causes frequent faults of the power system, and this brings various challenges to the stable operation of the power grid. Divided on a time scale, a power system fault can be divided into two transient phases (fault onset phase, fault clearance phase) and one steady-state phase (fault steady-state phase). Therefore, the stability problem of the new energy grid-connected system during the grid fault includes transient stability (large signal stability) in the fault transient stage and dynamic stability (small signal stability) in the fault steady-state stage. Transient stability of the fault transient stage can ensure that the grid-connected system has a balance point under the condition of the grid fault and can smoothly reach the balance point. On the other hand, during fault steady-state, transient components in the system have completely decayed. And the dynamic stability in the fault steady state period ensures that the grid-connected system keeps normal operation at the balance point in the fault steady state period until the fault is cleared. Therefore, the dynamic stability of the new energy grid-connected system during fault steady state is also important, and it may also affect the success rate of fault ride-through. At present, scholars at home and abroad research the dynamic stability of a new energy power generation system connected to a weak power grid based on a grid-connected converter.
(1) Huqi, fulijun, mafan, jifeng, zhangu, wang Guangyu, weak current network, based on the phase-locked control grid-connected converter small disturbance synchronous stability analysis [ J ], chinese Motor engineering report, 2021,41 (01): 98-108.
(2)J.Hu,B.Wang,W.Wang,H.Tang,Y.Chi and Q.Hu,“Small Signal Dynamics of DFIG-Based Wind Turbines During Riding Through Symmetrical Faults in Weak AC grid,”IEEE Transactions on Energy Conversion,vol.32,no.2,pp.720-730,Jun.2017.
The small signal stability of the grid-connected converter under a weak power grid is researched in the literature (1), and the influence of factors such as power grid impedance and controller parameters on the small signal stability is discussed. However, the small signal stability of grid-connected converters during weak grid faults has not been investigated. During the fault period, the small signal stability of the system is changed due to the change of the operation state and the grid structure of the grid-connected converter, and the grid-connected converter is easy to have the small signal instability phenomenon in the fault steady-state stage. How to improve the small-signal stability of the grid-connected converter during the weak grid fault needs to be studied.
Document (2) studies the small-signal stability of the doubly-fed wind power system during a weak grid symmetric voltage sag fault, however, does not study the dynamic stability during an asymmetric voltage sag fault. First, there is a dynamic coupling between the positive and negative sequence control systems, which affects the dynamic stability of the system during an asymmetric voltage sag fault. In addition, the effect of dynamic coupling between the negative sequence control system and the phase locked loop should also be considered. Due to the existence of the negative sequence component and the negative sequence power grid, compared with the symmetric fault, the problem of small signal stability of the grid-connected converter during the asymmetric voltage drop fault is more complicated. Therefore, how to improve the small-signal stability of the grid-connected converter during the steady state of the asymmetric voltage drop fault is not researched at present.
Disclosure of Invention
In view of the above defects in the prior art, the present invention aims to provide a grid-connected converter system control method during the asymmetric voltage drop fault of a weak grid, which redesigns the control strategy of a converter system on the basis of not increasing hardware devices. Disturbance caused by a phase-locked loop in a positive sequence control system and a negative sequence control system of the grid-connected converter under the asymmetric voltage drop fault is compensated and controlled, the small signal stability of the system during the asymmetric voltage drop fault is enhanced, and the success rate of ride-through of the asymmetric voltage drop fault is improved.
The technical scheme of the invention is realized as follows:
the small signal stability enhancement control strategy of the grid-connected converter under the weak grid asymmetric voltage drop fault is characterized in that: the method comprises the steps that under the condition of asymmetric voltage drop faults, disturbance caused by a phase-locked loop in a positive sequence control system and a negative sequence control system of a grid-connected converter is compensated and controlled;
(A) Compensating the influence of disturbance caused by a phase-locked loop under the asymmetric voltage drop fault on a grid-connected converter positive sequence control system, wherein the specific control steps are as follows:
a1 Calculate the dynamic delta theta of the PLL output according to the equations (1) and (2) pll+ ：
In the formula, G N (s) and G PI_PLL (s) a frequency doubling trap transfer function and a PI controller transfer function respectively applied in the phase locked loop,
ω 0 ＝200πrad/s，ξ＝0.707，
k p and k i Proportional coefficient and integral coefficient of PI controller; g PLL (s) is the transfer function of the phase locked loop;
the stable value of the positive sequence component of the grid-connected voltage of the system is obtained;
is the dynamic of the q-axis component of the positive sequence voltage of the grid-connected point, and can be formed by a positive sequence current loop
The difference between the actual value and 0. Where theta is pll+ Is the output of the phase-locked loop, theta pll+ ＝-θ pll- ；Δθ pll+ Is the error in the output of the phase locked loop, which cannot be directly measured, but can be calculated from equations (1) (2).
A2 Output dynamic delta theta of phase locked loop pll+ Positive sequence to system d axisGrid connection voltage
Output current
And an output voltage
System q-axis positive sequence grid-connected voltage
Output current
And an output voltage
Is calculated as in equation (3):
in the formula (I), the compound is shown in the specification,
and
expressing the dynamics of the positive sequence grid-connected voltage, the output current and the output voltage of the d axis of the system when the phase-locked loop outputs the dynamics;
and
expressing the dynamics of the q-axis positive sequence grid-connected voltage, the output current and the output voltage of the system when the phase-locked loop outputs the dynamics;
and
representing the dynamics of the positive sequence grid-connected voltage, the output current and the output voltage of a system d axis when the phase-locked loop outputs the dynamics;
and
representing the dynamics of the q-axis positive sequence grid-connected voltage, the output current and the output voltage of the system when the phase-locked loop outputs the dynamics;
and
stable values of a d-axis positive sequence component of the system positive sequence grid-connected voltage, the output current and the output voltage are obtained;
and
the stable values of the q-axis positive sequence component of the system positive sequence grid-connected voltage, the output current and the output voltage are obtained;
a3 Substituting formula (2) into formula (3) to calculate formula (4):
a4 Subtract the compensation term at the output of the positive sequence current loop
And
subtracting the compensation term at the input of the positive sequence current loop
Respectively eliminating the positive sequence grid-connected voltage of the phase-locked loop output dynamic pair system obtained in A3)
Output current
And an output voltage
Dynamic interference of (2). Wherein
The vector expression form of the system positive sequence grid-connected voltage, the output current and the output voltage is adopted;
the vector expression form of the stable values of the positive sequence grid-connected voltage, the output current and the output voltage of the system is adopted.
(B) Compensating the influence of disturbance caused by a phase-locked loop under the asymmetric voltage drop fault on a negative sequence control system of the grid-connected converter, wherein the specific control steps are as follows:
b1 Output dynamic delta theta of phase locked loop pll+ Negative sequence grid-connected voltage for system d shaft
Output current
And an output voltage
System q-axis positive sequence grid-connected voltage
Output current
And an output voltage
Is calculated according to equation (5):
in the formula (I), the compound is shown in the specification,
and
expressing the dynamics of the negative sequence grid-connected voltage, the output current and the output voltage of the d axis of the system when the output dynamics of the phase-locked loop is not considered;
and
expressing the dynamics of the q-axis negative sequence grid-connected voltage, the output current and the output voltage of the system when the phase-locked loop does not consider the output dynamics;
and
representing the dynamics of the negative sequence grid-connected voltage, the output current and the output voltage of a system d-axis when the output dynamics of the phase-locked loop are considered;
and
representing the dynamics of the q-axis negative sequence grid-connected voltage, the output current and the output voltage of the system when the phase-locked loop outputs the dynamics;
and
stable values of the d-axis positive sequence component of the system negative sequence grid-connected voltage, the output current and the output voltage are obtained;
and
stable values of q-axis positive sequence components of the system negative sequence grid-connected voltage, the output current and the output voltage are obtained;
b2 Substituting formula (2) into formula (5) to calculate formula (6):
b3 Subtract the compensation term at the output of the negative sequence current loop
And
subtracting the compensation term at the input of the negative-sequence current loop
Respectively eliminating negative sequence grid-connected voltage of phase-locked loop output dynamic pair system obtained in B2)
Output current
And an output voltage
Dynamic interference of (2). Wherein
The vector expression form of the system negative sequence grid-connected voltage, the output current and the output voltage is adopted;
the vector expression form of the stable values of the system negative sequence grid-connected voltage, the output current and the output voltage is adopted.
Compared with the prior art, the invention has the following beneficial effects:
the invention carries out compensation control on disturbance caused by a phase-locked loop in the positive sequence control system and the negative sequence control system of the grid-connected converter under the asymmetric voltage drop fault, enhances the small signal stability of the grid-connected converter during the asymmetric voltage drop fault, and improves the success rate of ride-through of the asymmetric voltage drop fault.
Drawings
Fig. 1 is a control block diagram of a grid-connected converter under an asymmetric voltage sag fault.
Fig. 2 is a schematic diagram of a phase-locked loop control structure adopted under an asymmetric voltage drop fault.
Fig. 3 is a control block diagram of a grid-connected converter adopting a small-signal stability enhancement control strategy.
Fig. 4 is a comparison graph of simulation waveforms of the grid-connected converter under the asymmetric voltage drop fault and with or without a small signal stability enhancement control strategy.
Detailed Description
The following detailed description of specific embodiments of the invention refers to the accompanying drawings.
Fig. 1 is a control block diagram of a grid-connected converter under an asymmetric voltage drop fault, in which a grid-connected converter system cuts off a power outer ring during the asymmetric voltage drop fault, only uses a current inner ring for control, and the system opens a negative sequence current control ring to control a negative sequence current component. U shape g Or U gdq The grid connection point voltage of the system; I.C. A g Or I gdq To output a current; v g Or V gdq Is the system output terminal voltage; z is a linear or branched member f Is the filter circuit impedance; z g Is the grid impedance; the + and-in the superscript or subscript represents the positive or negative sequence component, e.g.,
and
representing the positive sequence output current and the positive sequence grid-connected point voltage,
and
representing a negative sequence output current and a negative sequence grid-connected point voltage; the index ref indicates the reference value and the index pll indicates the quantity in the reference coordinate system detected by pll.
Fig. 2 is a schematic diagram of a control structure of a phase-locked loop adopted by a system under an asymmetric voltage drop fault, wherein a frequency doubling wave trap is added in the phase-locked loop to filter out the influence of a negative sequence component. G N (s) and G PI_PLL (s) a transfer function of a frequency-doubled trap applied in the phase-locked loop and a transfer function of the PI controller respectively,
ω 0 ＝200πrad/s，ξ＝0.707，
k p and k i Proportional coefficient and integral coefficient of the PI controller respectively.
Fig. 3 is a control block diagram of a grid-connected converter adopting a small-signal stability enhancement control strategy. Subtracting the compensation term at the output of the positive sequence current loop
And
subtracting the compensation term at the input of the positive sequence current loop
Respectively eliminating positive sequence grid-connected voltage of phase-locked loop output dynamic pair system
Output current
And an output voltage
Dynamic interference of (2); subtracting the compensation term at the output of the negative-sequence current loop
And
subtracting a compensation term at the input of the negative sequence current loop
Respectively eliminating negative sequence grid-connected voltage of phase-locked loop output dynamic pair system
Output current
And an output voltage
Dynamic interference of (2).
The method comprises the following specific implementation steps:
(A) Compensating the influence of disturbance caused by a phase-locked loop under the asymmetric voltage drop fault on a grid-connected converter positive sequence control system, wherein the specific control steps are as follows:
a1 Calculate the dynamic delta theta of the PLL output according to the equations (1) and (2) pll+ ：
In the formula, G N (s) and G PI_PLL (s) a frequency doubling trap transfer function and a PI controller transfer function respectively applied in the phase locked loop,
ω 0 ＝200πrad/s，ξ＝0.707，
k p and k i Proportional coefficient and integral coefficient of PI controller; g PLL (s) is the transfer function of the phase locked loop;
the voltage is a stable value of a positive sequence component of the grid-connected voltage of the system;
is the dynamic of the q-axis component of the positive sequence voltage of the grid-connected point, and can be formed by a positive sequence current loop
The difference between the actual value and 0. Where theta is pll+ Is the output of the phase-locked loop, θ pll+ ＝-θ pll- (ii) a Phase locked loop output dynamics delta theta pll+ Cannot be directly measured, but can be calculated by the formulas (1) and (2).
A2 Output dynamic delta theta of phase locked loop pll+ To system d-axis positive sequence grid-connected voltage
Output current
And an output voltage
System q-axis positive sequence grid-connected voltage
Output current
And an output voltage
Is calculated according to equation (3):
in the formula (I), the compound is shown in the specification,
and
expressing the dynamics of the positive sequence grid-connected voltage, the output current and the output voltage of the d axis of the system when the phase-locked loop does not consider the output dynamics;
and
expressing the dynamics of the q-axis positive sequence grid-connected voltage, the output current and the output voltage of the system when the phase-locked loop outputs the dynamics;
and
representing the dynamics of the positive sequence grid-connected voltage, the output current and the output voltage of a system d axis when the phase-locked loop outputs the dynamics;
and
representing the dynamics of the q-axis positive sequence grid-connected voltage, the output current and the output voltage of the system when the phase-locked loop outputs the dynamics;
and
stable values of a d-axis positive sequence component of the system positive sequence grid-connected voltage, the output current and the output voltage are obtained;
and
the stable values of the q-axis positive sequence component of the system positive sequence grid-connected voltage, the output current and the output voltage are obtained;
a3 Substituting formula (2) into formula (3) to calculate formula (4):
a4 Subtract the compensation term at the output of the positive sequence current loop
And
subtracting the compensation term at the input of the positive sequence current loop
Respectively eliminating the positive sequence grid-connected voltage of the phase-locked loop output dynamic pair system obtained in A3)
Output current
And an output voltage
Dynamic interference of (2). Wherein
The vector expression form of the positive sequence grid-connected voltage, the output current and the output voltage of the system is adopted;
the vector expression form of the stable values of the positive sequence grid-connected voltage, the output current and the output voltage of the system is adopted.
(B) Compensating the influence of disturbance caused by a phase-locked loop under the asymmetric voltage drop fault on a negative sequence control system of the grid-connected converter, wherein the specific control steps are as follows:
b1 Output dynamic delta theta of phase locked loop pll+ Negative sequence grid-connected voltage for system d shaft
Output current
And an output voltage
System q-axis negative sequence grid-connected voltage
Output current
And an output voltage
Is calculated as in equation (5):
in the formula (I), the compound is shown in the specification,
and
expressing the dynamics of the negative sequence grid-connected voltage, the output current and the output voltage of the system d-axis when the phase-locked loop outputs the dynamics;
and
expressing the dynamics of the q-axis negative sequence grid-connected voltage, the output current and the output voltage of the system when the phase-locked loop outputs the dynamics;
and
representing the dynamics of the negative sequence grid-connected voltage, the output current and the output voltage of a system d-axis when the output dynamics of the phase-locked loop are considered;
and
representing the dynamics of the q-axis negative sequence grid-connected voltage, the output current and the output voltage of the system when the phase-locked loop outputs the dynamics;
and
stable values of the d-axis positive sequence component of the system negative sequence grid-connected voltage, the output current and the output voltage are obtained;
and
stable values of q-axis positive sequence components of the system negative sequence grid-connected voltage, the output current and the output voltage are obtained;
b2 Substituting formula (2) into formula (5) to calculate formula (6):
b3 Subtract the compensation term at the output of the negative sequence current loop
And
subtracting the compensation term at the input of the negative-sequence current loop
Respectively eliminating negative sequence grid-connected voltage of phase-locked loop output dynamic pair system obtained in B2)
Output current
And an output voltage
Dynamic interference of (2). Wherein
The vector expression form of the system negative sequence grid-connected voltage, the output current and the output voltage is adopted;
the vector expression form of the stable values of the system negative sequence grid-connected voltage, the output current and the output voltage is adopted.
The results of the implementation of step A4) and step B3) together constitute the control object of the present invention.
Description of the effects of the invention:
fig. 4 shows a comparison diagram of simulation waveforms of the grid-connected converter when a small signal stability enhancement control strategy is present or absent in the case of an asymmetric voltage drop fault. U shape gabc For grid-connected converter system grid-connected point three-phase voltage, I gabc And outputting three-phase current for the grid-connected converter system. In the figure, the two-phase voltages of the system a and the system b drop when 1.5 s-2.5 s, and the phase voltage of the system c is kept constant. Wherein (a) and (b) are three-phase voltage and output of grid-connected point when small signal stability enhancement control strategy is not adoptedAnd (d) is a waveform diagram when a small signal stability enhancement control strategy is applied. It can be seen from the figure that when a small signal stability enhancement control strategy is not adopted, the small signal instability phenomenon occurs in the system during the fault period, and the small signal stability and the fault ride-through success rate of the grid-connected converter system are reduced. After the small signal stability enhancement control strategy is adopted, the small signal stability of the system during the fault period is effectively improved, the small signal instability phenomenon is avoided, and the fault ride-through success rate is improved.
In summary, the invention provides a small signal stability enhancement control strategy for a grid-connected converter under the asymmetric voltage drop fault of a weak grid, and the strategy has the following beneficial effects: the stability of the small signal of the system during the asymmetric voltage drop fault is enhanced, the phenomenon of small signal instability possibly occurring during the fault is avoided, and the success rate of fault ride-through is improved.
Finally, it should be noted that the above-mentioned examples of the present invention are only examples for illustrating the present invention, and are not intended to limit the embodiments of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, it will be apparent to those skilled in the art that other variations and modifications can be made based on the above description. It is not exhaustive here for all embodiments. All obvious changes and modifications of the present invention are within the scope of the present invention.
Claims (1)
1. The small signal stability enhancement control strategy of the grid-connected converter under the weak grid asymmetric voltage drop fault is characterized in that: the influence of disturbance caused by a phase-locked loop under the asymmetric voltage drop fault on a positive sequence control system and a negative sequence control system of the grid-connected converter is respectively compensated, so that the small signal stability of the system during the asymmetric voltage drop fault is enhanced;
(A) Compensating the influence of disturbance caused by a phase-locked loop under the asymmetric voltage drop fault on a grid-connected converter positive sequence control system, wherein the specific control steps are as follows:
a1 ) is pressedThe dynamic delta theta of the phase-locked loop output is calculated by the formula (1) and the formula (2) pll+ ：
In the formula, G N (s) and G PI_PLL (s) a frequency doubling trap transfer function and a PI controller transfer function respectively applied in the phase locked loop,
ω 0 ＝200πrad/s，ξ＝0.707，
k p and k i Proportional coefficient and integral coefficient of PI controller; g PLL (s) is the transfer function of the phase locked loop;
the stable value of the positive sequence component of the grid-connected voltage of the system is obtained;
is the dynamic of the q-axis component of the positive sequence voltage of the grid-connected point, and is formed by a positive sequence current loop
The difference between the actual value and 0;
a2 Output dynamic delta theta of phase locked loop pll+ To system d-axis positive sequence grid-connected voltage
Output current
And an output voltage
System q-axis positive sequence grid-connected voltage
Output current
And an output voltage
Is calculated as in equation (3):
in the formula (I), the compound is shown in the specification,
and
expressing the dynamics of the positive sequence grid-connected voltage, the output current and the output voltage of the d axis of the system when the phase-locked loop does not consider the output dynamics;
and
expressing the dynamics of the q-axis positive sequence grid-connected voltage, the output current and the output voltage of the system when the phase-locked loop outputs the dynamics;
and
representing the dynamics of the positive sequence grid-connected voltage, the output current and the output voltage of a system d axis when the phase-locked loop outputs the dynamics;
and
representing the dynamics of the q-axis positive sequence grid-connected voltage, the output current and the output voltage of the system when the phase-locked loop outputs the dynamics;
and
a stable value of a d-axis positive sequence component of the grid-connected voltage, the output current and the output voltage is a system positive sequence grid-connected voltage;
and
the stable values of the q-axis positive sequence component of the system positive sequence grid-connected voltage, the output current and the output voltage are obtained;
a3 Substituting formula (2) into formula (3) to calculate formula (4):
a4 Subtract the compensation term at the output of the positive sequence current loop
And
in the positive-sequence current loopInput subtracting compensation term
Respectively eliminating the positive sequence grid-connected voltage of the phase-locked loop output dynamic pair system obtained in A3)
Output current
And an output voltage
Dynamic interference of (2); wherein
The vector expression form of the positive sequence grid-connected voltage, the output current and the output voltage of the system is adopted;
the vector expression form of the stable values of the positive sequence grid-connected voltage, the output current and the output voltage of the system is adopted;
(B) The method is used for compensating the influence of disturbance on a grid-connected converter negative sequence control system caused by a phase-locked loop under the asymmetric voltage drop fault, and comprises the following specific control steps:
b1 Output dynamic delta theta of phase locked loop pll+ Negative sequence grid-connected voltage for system d axis
Output current
And an output voltage
System q-axis negative sequence grid-connected voltage
Output current
And an output voltage
Is calculated according to equation (5):
in the formula (I), the compound is shown in the specification,
and
expressing the dynamics of the negative sequence grid-connected voltage, the output current and the output voltage of the system d-axis when the phase-locked loop outputs the dynamics;
and
expressing the dynamics of the q-axis negative sequence grid-connected voltage, the output current and the output voltage of the system when the phase-locked loop outputs the dynamics;
and
representing the dynamics of the negative sequence grid-connected voltage, the output current and the output voltage of a system d shaft when the phase-locked loop outputs the dynamics;
and
representing the dynamics of the q-axis negative sequence grid-connected voltage, the output current and the output voltage of the system when the phase-locked loop outputs the dynamics;
and
stable values of the d-axis positive sequence component of the system negative sequence grid-connected voltage, the output current and the output voltage are obtained;
and
stable values of q-axis positive sequence components of the system negative sequence grid-connected voltage, the output current and the output voltage are obtained;
b2 Substituting formula (2) into formula (5) to calculate formula (6):
b3 Subtract the compensation term at the output of the negative sequence current loop
And
subtracting a compensation term at the input of the negative sequence current loop
Respectively eliminating negative sequence grid-connected voltage of phase-locked loop output dynamic pair system obtained in B2)
Output current
And an output voltage
Dynamic interference of (2); wherein
The vector expression form of the system negative sequence grid-connected voltage, the output current and the output voltage is adopted;
the vector expression form of the stable values of the system negative sequence grid-connected voltage, the output current and the output voltage is adopted.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140138949A1 (en) * | 2012-04-24 | 2014-05-22 | Masdar Institute Of Science And Technology | Fault handling system for doubly fed induction generator |
| WO2019119667A1 (en) * | 2017-12-18 | 2019-06-27 | 广东工业大学 | Control method for variable frequency transformer fault ride through circuit and related circuit |
| CN112217237A (en) * | 2020-10-23 | 2021-01-12 | 内蒙古电力(集团)有限责任公司包头供电局 | Active damping control method for direct-drive wind power grid-connected system under asymmetric fault |
| CN112217236A (en) * | 2020-10-23 | 2021-01-12 | 内蒙古电力(集团)有限责任公司包头供电局 | Virtual impedance control method for double-fed wind power grid-connected system under asymmetric fault |
| CN113644667A (en) * | 2021-06-30 | 2021-11-12 | 中国电力科学研究院有限公司 | Method and system for calculating asymmetric fault components of power distribution network under inverter control strategy |
| CN113890436A (en) * | 2021-10-28 | 2022-01-04 | 江苏方天电力技术有限公司 | Double-fed wind turbine generator rotor side coordination control method based on symmetric and asymmetric power grid faults |
-
2022
- 2022-07-27 CN CN202210892279.3A patent/CN115207912B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140138949A1 (en) * | 2012-04-24 | 2014-05-22 | Masdar Institute Of Science And Technology | Fault handling system for doubly fed induction generator |
| WO2019119667A1 (en) * | 2017-12-18 | 2019-06-27 | 广东工业大学 | Control method for variable frequency transformer fault ride through circuit and related circuit |
| CN112217237A (en) * | 2020-10-23 | 2021-01-12 | 内蒙古电力(集团)有限责任公司包头供电局 | Active damping control method for direct-drive wind power grid-connected system under asymmetric fault |
| CN112217236A (en) * | 2020-10-23 | 2021-01-12 | 内蒙古电力(集团)有限责任公司包头供电局 | Virtual impedance control method for double-fed wind power grid-connected system under asymmetric fault |
| CN113644667A (en) * | 2021-06-30 | 2021-11-12 | 中国电力科学研究院有限公司 | Method and system for calculating asymmetric fault components of power distribution network under inverter control strategy |
| CN113890436A (en) * | 2021-10-28 | 2022-01-04 | 江苏方天电力技术有限公司 | Double-fed wind turbine generator rotor side coordination control method based on symmetric and asymmetric power grid faults |
Non-Patent Citations (2)
| Title |
|---|
| J.HU等: "Small Signal Dynamics of DFIG-Based Wind Turbines During Riding Through Symmetrical Faults in Weak AC grid", 《IEEE TRANSACTIONS ON ENERGY CONVERSION》, vol. 32, no. 2, 30 June 2017 (2017-06-30), pages 720 - 730 * |
| X. HE等: "Transient stability analysis and enhancement of renewable energy conversion system during LVRT", 《EEE TRANSACTIONS ON SUSTAINABLE ENERGY》, vol. 11, no. 3, 31 July 2020 (2020-07-31), pages 1612 - 1623, XP011794349, DOI: 10.1109/TSTE.2019.2932613 * |
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