CN110501919B - Design method of digital physical hybrid simulation interface of modular multilevel converter - Google Patents
Design method of digital physical hybrid simulation interface of modular multilevel converter Download PDFInfo
- Publication number
- CN110501919B CN110501919B CN201910791645.4A CN201910791645A CN110501919B CN 110501919 B CN110501919 B CN 110501919B CN 201910791645 A CN201910791645 A CN 201910791645A CN 110501919 B CN110501919 B CN 110501919B
- Authority
- CN
- China
- Prior art keywords
- mmc
- bridge arm
- equivalent
- conversion coefficient
- 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.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B17/00—Systems involving the use of models or simulators of said systems
- G05B17/02—Systems involving the use of models or simulators of said systems electric
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Inverter Devices (AREA)
Abstract
The invention discloses a design method of a digital physical hybrid simulation interface of a modular multilevel converter, which comprises the following steps: step one, deducing an MMC mathematical model according to an MMC operation principle; designing a digital physical interface conversion coefficient to ensure that the response of the MMC experiment platform is equivalent to the response of the corresponding high-power MMC convertor station through the digital physical interface conversion coefficient; and thirdly, simplifying a mathematical model of the MMC according to the operation characteristics of the MMC, enabling each bridge arm of the MMC to be equivalent to a variable capacitor controlled by a modulation wave, enabling each phase of the MMC to be equivalent to an RLC series branch consisting of upper and lower bridge arm inductors, bridge arm parasitic resistors and equivalent variable capacitors, and deducing DIM compensation impedance after conversion of a conversion coefficient in an s domain by considering the influence of the conversion coefficient on circuit parameters. The invention has simple structure and easy realization, and can meet the requirements of stability and accuracy of a digital physical hybrid simulation system.
Description
Technical Field
The invention belongs to the field of power electronics, and relates to a design method of a digital physical hybrid simulation interface of a modular multilevel converter.
Background
A direct-current power grid formed by a Modular Multilevel Converter (MMC) has complex dynamic behaviors and fast transient response, and the traditional digital simulation cannot simultaneously meet the requirements of simulation speed and precision. The equal-proportion physical dynamic simulation experiment platform prototype can be used for simulating a flexible direct-current power grid, but the scheme is very high in cost, and a ground object is fixed and poor in simulation flexibility. Therefore, the verification of the flexible direct current power grid related theory must adopt a more advanced simulation method.
Digital physical hybrid simulation, also called power hardware-in-the-loop (PHIL) simulation, simulates the part of the system which is large in scale and difficult to build by hardware by using a real-time digital simulator, realizes the part which is important to research or structure load and difficult to accurately model by using real physical equipment, forms a digital physical hybrid simulation system which has both a digital simulation object and actual physical equipment to be tested, and is an effective means for research and engineering design verification of a flexible direct current power grid.
In order to connect the digital side and the physical side, a proper digital physical interface needs to be designed. The Damping Impedance Method (DIM) has very high stability margin and precision when the compensation impedance is completely the same as the physical side equivalent impedance, and is an interface method with the widest application. For a flexible direct current power transmission PHIL system, a physical side is nonlinear power electronic equipment such as an MMC (modular multilevel converter), and an accurate mathematical model of the nonlinear power electronic equipment presents complex time-varying nonlinearity and is often difficult to obtain. On the other hand, MMCs in laboratories tend to have difficulty reaching flexibly engineered voltage and power levels, subject to the constraints of the laboratory research environment and the output limitations of the power amplifier. For this purpose, a corresponding conversion coefficient should be set at the digital physical interface so as to convert the MMC with low power level into the MMC with high power at the level of the flexible system. When the interface conversion coefficient exists, the compensation impedance of the DIM method will also change under the influence of the interface conversion coefficient, however, at present, there is no accurate and detailed theoretical research, and there is no design basis.
Disclosure of Invention
The invention provides a design method of a digital-physical hybrid simulation interface of a modular multilevel converter, aiming at the problem that the influence of a conversion coefficient of a digital-physical interface on the compensation impedance of a DIM interface is lack of theoretical basis. The invention simplifies the mathematical model of the modular multilevel converter according to the operating characteristics of the modular multilevel converter and deduces the damping impedance interface compensation impedance after conversion of the conversion coefficient. The method has simple structure and easy realization, and can meet the requirements of stability and accuracy of a digital physical hybrid simulation system.
The purpose of the invention is realized by the following technical scheme:
a design method for a digital physical hybrid simulation interface of a modular multilevel converter comprises the following steps:
step one, deducing an MMC mathematical model according to an MMC operation principle, wherein the MMC mathematical model is as follows:
in the formula, R, L represents the equivalent resistance of the MMC bridge arm and the inductance of the bridge arm reactor, ujDenotes j alternating voltage, uDCRepresenting the DC bus voltage uujIs the j-phase upper bridge arm voltage, iujAnd iljJ phase upper and lower bridge arm currents, mujAnd mljThe modulation waves of the j-phase upper bridge arm and the j-phase lower bridge arm are respectively, N is the number of the sub-modules, and C is a sub-module capacitor;
step two, designing a digital physical interface conversion coefficient, ensuring that the response of the MMC experiment platform is equivalent to the response of a corresponding high-power MMC converter station through the digital physical interface conversion coefficient, wherein the time domain expression of the MMC experiment platform converted to the high-power MMC converter station grade is as follows:
the relation between MMC topological parameters of the MMC experiment platform and the high-power MMC converter station is as follows:
in the formula, kuAnd kiThe conversion coefficients of voltage and current of the large-power MMC and the small-power MMC are respectively, and the prime sign' ″ represents the physical quantity of the large-power MMC;
step three, according to MMSimplifying a mathematical model by using a C operation characteristic, enabling each bridge arm of the MMC to be equivalent to a variable capacitor controlled by a modulation wave, enabling the sum of the number of sub-modules input by an upper bridge arm and a lower bridge arm to be constantly equal to N in order to ensure that the output voltage of a direct current side is constant when the MMC normally operates, enabling each phase of the MMC to be equivalent to an RLC series branch consisting of an upper bridge arm inductor, a lower bridge arm inductor, a bridge arm parasitic resistor and an equivalent variable capacitor, and deducing DIM compensation impedance after conversion of a conversion coefficient under an s domain in consideration of the influence of the conversion coefficient on circuit parameters, wherein the compensation impedance Z is*Comprises the following steps:
according to the invention, an MMC mathematical model is deduced according to an MMC operation principle, equivalent impedance of a direct current side of the MMC at a physical side is converted according to a digital physical transformation ratio, and compensation impedance suitable for a DIM method is deduced. Compared with the prior art, the invention has the following advantages:
1. aiming at the problem that the digital and physical side power grades of a flexible direct current transmission digital physical hybrid simulation system are different, the invention derives the conversion coefficient between the parameters of the high-power converter station and the low-power converter station in detail from the mathematical model of the modular multi-level converter, and ensures that the low-power dynamic simulation platform can accurately reflect the characteristics of the flexible direct current converter station.
2. The invention deduces the MMC direct current side equivalent impedance model on the basis of fully considering the problem of different power levels of the digital side and the physical side of the flexible-straight PHIL system, so that the MMC direct current side equivalent impedance model is suitable for the compensation impedance of the flexible-straight PHIL damping impedance interface.
3. The invention can ensure that the low-power MMC experiment platform can accurately reflect the characteristics of the flexible-direct current converter station, and the damping impedance interface can meet the requirements of the stability and accuracy of flexible-direct PHIL simulation, and has strong applicability.
Drawings
Fig. 1 is a schematic of a topology of a prior art three-phase modular multilevel converter;
FIG. 2 is a schematic diagram of a back-to-back flexible DC power transmission PHIL system;
FIG. 3 is a simplified model of the DC-side equivalent impedance of an MMC;
fig. 4 is a waveform of a dc bus short-circuit fault experiment.
Detailed Description
The technical solution of the present invention is further described below with reference to the accompanying drawings, but not limited thereto, and any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be covered by the protection scope of the present invention.
The invention provides a design method of a digital-physical hybrid simulation interface of a modular multilevel converter on the basis of considering digital-physical transformation ratio, which comprises the following specific steps:
step one, deducing an MMC mathematical model according to an MMC operation principle.
The topology of the existing three-phase modular multilevel converter is shown in fig. 1. Each phase comprises an upper bridge arm and a lower bridge arm, each bridge arm comprises a bridge arm reactor L and N submodules with the same structure, each submodule is formed by connecting a power unit and a capacitor C in parallel, and each power unit is in a half-bridge structure or other similar power units.
According to kirchhoff's law, the circuit equation of MMC is written as follows:
ij＝ilj-iuj (4)；
wherein R, L respectively represents MMC bridge arm equivalent resistance and bridge arm reactor inductance, ujRepresenting j ac voltage，uDCRepresenting the DC bus voltage uujAnd uljJ-phase upper and lower bridge arm voltages, iDCRepresenting a direct current, iujAnd iljJ-phase upper and lower bridge arm currents respectively.
Further, define suj(k) The switching function of the kth submodule in the j-phase upper bridge arm reflects the switching state of the submodules:
when the kth sub-module of the upper bridge arm of the j phase is put in, suj(k) 1, the output voltage u of the submoduleuj(k) Equal to the sub-module capacitor voltage uCuj(k) Capacitance current iCuj(k) Equal to bridge arm current iuj(ii) a When the kth sub-module of the upper bridge arm of the j phase is cut off, suj(k) Is 0, the submodule outputs a voltage uuj(k) And a capacitance current iCuj(k) Are all 0. Thus, the following set of equations can be written for each submodule of the j-phase upper leg in the column:
uuj(k)＝suj(k)uCuj(k) (6)；
iCuj(k)＝suj(k)iuj (7)；
the equation of the lower bridge arm submodule is similar to that of the upper bridge arm submodule:
ulj(k)＝slj(k)uClj(k) (9)；
iClj(k)＝slj(k)ilj (10)；
the formula describes a detailed mathematical model of the MMC represented by a switching function, and the capacitance of each submodule corresponds to a differential equation, so that the model becomes very complex when the number of submodules is large. For simplification, the above-mentioned high-order model is processed by using a bridge arm averaging method. Assuming that the capacitor voltage and the current of all the sub-modules in the same bridge arm are equal and meet the following conditions:
uCuj(k)＝uCuj (12)；
iCuj(k)＝iCuj (13)。
the sum of the switching functions of all submodules in the bridge arm is equal to the modulation wave of the bridge arm, i.e.:
wherein m isujFor the modulation wave of the bridge arm on the j phase, the value range of the modulation wave is [0,1 ] for the half-bridge submodule]The input ratio of one bridge arm submodule is shown. The expressions (12) to (14) are taken to the expressions (1) to (8), and are simplified to obtain:
ij＝ilj-iuj (18)；
uuj＝NmujuCuj (19)；
in order to more intuitively embody the relation between the MMC alternating-direct current voltage and the bridge arm current and control, the formula is rewritten:
wherein m isljThe modulation wave of the j-phase lower bridge arm is obtained, N is the number of the sub-modules, and C is the sub-module capacitor.
And designing a conversion coefficient of the digital physical interface to ensure that the response of the MMC experiment platform can be equivalent to the response of the corresponding high-power MMC convertor station through the conversion coefficient of the digital physical interface.
Fig. 2 is a system structure diagram mentioned in the method, wherein the digital side is a constant voltage flexible direct-current converter station, and the physical side is a constant power converter station model, and the two are connected through a digital physical interface. The digital physical interface method is a damping impedance method, and the three-phase alternating current output end of the physical-side low-power MMC prototype is connected with a resistive load R' load.
According to the method, the voltage, the current and the power are mutually constrained according to the condition that the P is equal to UI, and once two variables are determined, the value of the third variable is fixed accordingly. Based on this, only two of the three conversion factors of voltage, current and power need to be determined.
The digital physical interface only feeds back port voltage or current signals of the physical side to the digital side, but physical quantities with the same property in the physical side are in fixed proportional relation.
The expressions (21) and (22) show that the MMC mathematical model only contains voltage, current, topological parameters and control parameters, and does not directly reflect the change of power, and the digital physical interface conversion coefficient only considers the voltage and current conversion coefficients:
wherein k isuAnd kiThe conversion coefficients of voltage and current of the large-power MMC and the small-power MMC are respectively, and the prime sign of the prime sign indicates the physical quantity of the large-power MMC.
Only when the control modes of the low-power MMC experiment platform and the high-power converter station obtained after conversion are completely the same, the modulation signals generated by the low-power MMC experiment platform and the high-power converter station can be completely consistent, and the stable state and the dynamic characteristic between the large MMC experiment platform and the small MMC experiment platform are ensured to present a fixed proportional relation. The two modulated waves can be expressed as:
substituting the formulas (23) and (24) into the formulas (21) and (22) to obtain a time domain expression of the low-power MMC dynamic simulation experiment platform converted to the high-power converter station level:
the response of the MMC dynamic model platform can be equivalent to the response of a corresponding high-power MMC converter station through the conversion coefficient of a digital physical interface, and the equations (24) and (25) are required to be correspondingly equal to the equations (20) and (21), so that the relation between two MMC topological parameters is obtained:
and step three, simplifying a mathematical model of the MMC according to the operation characteristics of the MMC, and deducing DIM method compensation impedance after conversion of a conversion coefficient.
The essence of MMC operation is that the quantity of submodules put into each bridge arm is continuously changed by modulating waves, so that electric energy conversion is realized. According to the process, each bridge arm of the MMC can be equivalent to a variable capacitor controlled by the modulation wave.
As can be seen from the operation principle of the MMC, the direct current flows only along the circular current path without entering the ac side, and therefore the load connected to the ac side is ignored when determining the dc side impedance of the MMC. And bridge arm inductors of the upper bridge arm and the lower bridge arm of the MMC, bridge arm parasitic resistors and equivalent variable capacitors form an RLC series branch. Fig. 3 is a simplified model of the equivalent impedance of the MMC dc side on the physical side of the method, and the impedance thereof can be expressed as:
when the MMC normally operates, in order to ensure that the output voltage of the direct current side is constant, the upper and lower bridge arm submodules are generally required to be symmetrically and complementarily put into use, that is, the sum of the numbers of the submodules put into the upper and lower bridge arms at any moment is always equal to N (the double frequency component of the modulation wave generated by the circulating current suppression is ignored), so that m is muj+m lj1. The above equation can thus be simplified to:
and then can try to obtain the analytic formula of MMC direct current side impedance:
compensating impedance Z applied to digital physical information interface connected to digital side in consideration of the influence of conversion coefficient of digital physical interface*The following should be written:
according to the method for designing the digital physical hybrid simulation interface of the modular multilevel converter, an embodiment of a back-to-back flexible-to-straight PHIL system is designed. And determining a 201-level constant voltage converter station with a digital side of 100MW and 300kV, wherein the voltage conversion coefficient is 0.001, and the current conversion coefficient is 100, so that the response of the physical side prototype is equivalent to the constant power converter station under the soft-direct level after being converted. The 1kW, 300V constant power converter station model on the physical side is connected with the digital side through a DIM interface, and the system parameters are given in Table 1.
TABLE 1 Experimental parameters
And carrying out a direct current bus short circuit fault experiment on the back-to-back flexible direct current PHIL system. As can be seen from the experimental waveforms of fig. 4, the DIM compensation impedance design method can satisfy the system stability and accuracy.
Claims (3)
1. A design method for a digital physical hybrid simulation interface of a modular multilevel converter is characterized by comprising the following steps:
step one, deducing an MMC mathematical model according to an MMC operation principle, wherein the MMC mathematical model is as follows:
in the formula (I), the compound is shown in the specification,R、Lrespectively showing the equivalent resistance of the bridge arm of the MMC and the inductance of the bridge arm reactor,u jto representjThe alternating-current voltage is applied to the coil,u DCwhich represents the voltage of the dc bus,u juis composed ofjThe voltage of the bridge arm on the phase is high,i juandi jlare respectively asjThe current of the upper bridge arm and the lower bridge arm of the phase,m juandm jlare respectively asjThe modulated waves of the upper and lower bridge arms are compared,Nthe number of the sub-modules is,Cis a sub-module capacitor;
step two, designing a digital physical interface conversion coefficient, ensuring that the response of the MMC experiment platform is equivalent to the response of the corresponding high-power MMC converter station through the digital physical interface conversion coefficient, and converting the MMC experiment platform into a time domain expression of the high-power MMC converter station grade, wherein the time domain expression is as follows:
the relation between MMC topological parameters of the MMC experiment platform and the high-power MMC converter station is as follows:
in the formula (I), the compound is shown in the specification,k uandk iconversion coefficients of voltage and current of large and small power MMC, respectively, superscript''"represents a physical quantity of the high-power MMC;
and thirdly, simplifying a mathematical model of the MMC according to the operation characteristics of the MMC, enabling each bridge arm of the MMC to be equivalent to a variable capacitor controlled by a modulation wave, enabling each phase of the MMC to be equivalent to an RLC series branch consisting of upper and lower bridge arm inductors, bridge arm parasitic resistors and equivalent variable capacitors, and deducing DIM compensation impedance after conversion of a conversion coefficient in an s domain by considering the influence of the conversion coefficient on circuit parameters.
2. The design method of the digital physical hybrid simulation interface of the modular multilevel converter according to claim 1, wherein the compensation impedance in the s-domain in the third stepZ *Comprises the following steps:
3. the design method of the digital physical hybrid simulation interface of the modular multilevel converter according to claim 1, wherein in the third step, when the MMC operates normally, in order to ensure that the output voltage of the dc side is constant, the sum of the numbers of the submodules put into the upper and lower bridge arms is constantly equal to that of the submodules put into the MMCN，NIs aThe number of modules.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910791645.4A CN110501919B (en) | 2019-08-26 | 2019-08-26 | Design method of digital physical hybrid simulation interface of modular multilevel converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910791645.4A CN110501919B (en) | 2019-08-26 | 2019-08-26 | Design method of digital physical hybrid simulation interface of modular multilevel converter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110501919A CN110501919A (en) | 2019-11-26 |
| CN110501919B true CN110501919B (en) | 2022-05-03 |
Family
ID=68589608
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910791645.4A Active CN110501919B (en) | 2019-08-26 | 2019-08-26 | Design method of digital physical hybrid simulation interface of modular multilevel converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110501919B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111382550B (en) * | 2020-03-10 | 2023-04-18 | 南方电网科学研究院有限责任公司 | Dynamic combination real-time simulation method of modular multilevel converter and use method |
| CN113098244B (en) * | 2021-04-07 | 2022-05-06 | 全球能源互联网研究院有限公司 | Bridge arm reactance unit of MMC (modular multilevel converter) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102663174A (en) * | 2012-03-23 | 2012-09-12 | 浙江大学 | Simulation method of MMC (modular multilevel converter) and application thereof |
| CN103746392A (en) * | 2013-12-19 | 2014-04-23 | 思源电气股份有限公司 | Static compensator model prediction control method based on modularized multilevel transverter |
| CN107359605A (en) * | 2017-09-12 | 2017-11-17 | 东北电力大学 | A kind of suppression module multilevel converter DC side fault overcurrent method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103593520B (en) * | 2013-10-31 | 2016-08-10 | 南方电网科学研究院有限责任公司 | A kind of equivalent simulation calculation modeling method of modularization multi-level converter |
| CN106294892B (en) * | 2015-05-14 | 2019-03-08 | 国网浙江省电力公司 | A method of judging MMC numerical model analysis simulated power interface stability |
| CN104933247B (en) * | 2015-06-16 | 2018-04-24 | 东北电力大学 | A kind of MMC numerical model analysis analogue system Accuracy Analysis method |
| CN107123981B (en) * | 2017-03-31 | 2021-08-06 | 全球能源互联网研究院 | Flexible direct current and direct current power grid electromechanical transient simulation method and system based on MMC |
| CN107609283B (en) * | 2017-09-20 | 2020-12-29 | 天津大学 | Modular multilevel converter efficient modeling method based on equivalent capacitance of bridge arm |
| CN108599227B (en) * | 2018-06-11 | 2020-04-14 | 中国电力工程顾问集团中南电力设计院有限公司 | MMC direct-current voltage balance control method for forming direct-current converter station based on MMC cascade connection |
-
2019
- 2019-08-26 CN CN201910791645.4A patent/CN110501919B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102663174A (en) * | 2012-03-23 | 2012-09-12 | 浙江大学 | Simulation method of MMC (modular multilevel converter) and application thereof |
| CN103746392A (en) * | 2013-12-19 | 2014-04-23 | 思源电气股份有限公司 | Static compensator model prediction control method based on modularized multilevel transverter |
| CN107359605A (en) * | 2017-09-12 | 2017-11-17 | 东北电力大学 | A kind of suppression module multilevel converter DC side fault overcurrent method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110501919A (en) | 2019-11-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Zhong et al. | H control of the neutral point in four-wire three-phase DC-AC converters | |
| Zhang et al. | A grid simulator with control of single-phase power converters in DQ rotating frame | |
| CN108229021B (en) | Blocking modeling method of modular multilevel converter based on real-time digital simulator | |
| CN110501919B (en) | Design method of digital physical hybrid simulation interface of modular multilevel converter | |
| CN113036797B (en) | Direct power control method and device for multi-level converter | |
| CN112100962A (en) | Electromagnetic transient simulation method and system of MMC (Modular multilevel converter) | |
| CN109193745B (en) | Third harmonic suppression device in flexible direct current transmission system and transmission system | |
| Patel et al. | Nonlinear adaptive volterra filter for control of distribution static compensator | |
| CN105785976A (en) | Test method of control protection device in flexible direct current transmission and system thereof | |
| Zhong et al. | $ H^ infty $ control of the neutral point in four-wire three-phase DC–AC converters | |
| CN109067147B (en) | Method for extracting capacitance voltage disturbance quantity and unbalance degree of submodule of cascaded converter | |
| Narayanan et al. | A virtual impedance based grid emulator for the performance analysis of distributed generations | |
| Hwang et al. | Harmonic State-Space modelling of an HVdc converter | |
| Urtasun et al. | Control design and stability analysis of power converters: The discrete generalized bode criterion | |
| CN104393777A (en) | Half-bridge MMC (Modular Multilevel Converter) sub-module voltage control method | |
| CN112140945B (en) | Simulation modeling system and method for traction power supply system of motor train unit | |
| Rajesvaran et al. | Modeling modular multilevel converters using extended-frequency dynamic phasors | |
| CN205608513U (en) | Controlled protection device's test system among flexible direct current transmission | |
| CN109412188B (en) | Nonlinear programming-based parameter optimization method for flexible direct current transmission hybrid simulation platform | |
| CN110460252B (en) | Power electronic system working condition simulation device with input LC filter | |
| Krishna et al. | Designing of multilevel DPFC to improve power quality | |
| Zhang et al. | Harmonic state space impedance model of MMC considering internal impedance of AC and DC Grid | |
| CN111737942B (en) | Steady-state harmonic calculation method for three-phase three-wire system modular multilevel converter | |
| CN115542147A (en) | Power-stage motor simulation device | |
| Kwon et al. | Analysis of harmonic coupling and stability in back-to-back converter systems for wind turbines using Harmonic State Space (HSS) |
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 |