CN114188985A - Power grid simulation device and test device for testing stability of virtual synchronous machine - Google Patents
Power grid simulation device and test device for testing stability of virtual synchronous machine Download PDFInfo
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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
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/40—Synchronising a generator for connection to a network or to another generator
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/003—Environmental or reliability tests
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- 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
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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
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
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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
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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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
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
Abstract
The invention provides a power grid simulation device and a test device for testing the stability of a virtual synchronous machine, wherein a voltage control type converter adopts a virtual inertia control module and a virtual impedance control module to realize the port characteristic of a simulated power grid, and has higher switching frequency; the current control type converter absorbs or generates port load current of a simulated power grid by adopting a current control module, and has lower switching frequency; the alternating current sides of the two converters are connected in parallel and then are directly connected with the port of the simulated power grid, or are connected with the port of the simulated power grid through an electrical impedance network. The virtual inertia amount control module eliminates discrete differential operators in part of control links by combining different control links together. The method effectively simulates the impedance characteristic and the inertia characteristic of the power grid of the low and medium frequency bands, and efficiently realizes the stability test of the synchronous generator or the virtual synchronous machine converter under the conditions of different power grid impedances and different power grid inertias.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to a power grid simulation device and a test device for testing the stability of a virtual synchronous machine.
Background
In recent years, with the large-scale application of new energy power generation, the proportion of grid-connected converters in a power grid is higher and higher. The grid-connected converter adopting the traditional control strategy does not contain inertia, so that the inertia of a power grid becomes low, and the frequency stability becomes poor. In order to improve the inertia of a power grid, the grid-connected converter adopts a virtual synchronous machine control strategy to simulate the inertia of a synchronous machine. The typical virtual synchronous machine comprises two control loops, namely a virtual synchronous machine control loop and a voltage/current inner loop, wherein the two control loops are obviously coupled with the power grid inertia and the power grid impedance, and the coupling can cause low-frequency active oscillation and intermediate-frequency voltage current resonance.
In order to ensure the stability of a power grid, the grid-connected converter adopting the virtual synchronous machine control strategy needs to be subjected to stability test before grid connection. In the traditional virtual synchronous machine stability test, a motor is connected with an actual inductor in series to simulate the characteristics of a power grid. This test method has the following limitations:
the cost is high; this approach requires different inductances to simulate different impedances and different motors to simulate different inertias.
The accuracy is low; the inductor is a nonlinear device, and the inductance values are different when different current values flow.
The flexibility is poor; when different short circuit ratios are tested, the inductor needs to be replaced continuously; the inertia parameters of the actual motor are not adjustable.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a power grid simulation device and a test device for testing the stability of a virtual synchronous machine.
According to one aspect of the invention, a power grid simulation device for testing the stability of a virtual synchronous machine is provided, which comprises a current control type converter, a voltage control type converter, a first direct current power supply port, a second direct current power supply port, an alternating current test port, a voltage converter control system and a current converter control system; wherein:
the ports of the current control type converter comprise a direct current input end and an alternating current output end, and the ports of the voltage control type converter comprise a direct current input end and an alternating current output end;
the direct current input end of the current control type converter is connected with the first direct current power supply port, the direct current input end of the voltage control type converter is connected with the second direct current power supply port, and the first direct current power supply port and the second direct current power supply port are respectively connected with an external power supply;
the alternating current output end of the current control type converter is connected with the alternating current test port after being connected in parallel with the alternating current output end of the voltage control type converter; the alternating current test port outputs the characteristics of a power grid and is connected with an external converter to be tested;
the voltage control type converter comprises a high switching frequency converter and an electrical impedance network B which are connected with each other, and is used for realizing simulation of the simulated low and medium frequency power grid impedance and low frequency inertia by controlling the voltage of the alternating current test port; the electrical impedance network B is used for filtering voltage harmonic waves;
the current control type converter comprises a low switching frequency converter and an electrical impedance network A which are connected with each other, and is used for supplying or absorbing the power of the converter to be tested by sending or absorbing the fundamental frequency or low-frequency current of an alternating current test port; wherein, the electrical impedance network A is used for filtering current harmonic waves;
the voltage converter control system comprises a virtual inertia control module, a virtual impedance control module and a high-frequency pulse width modulator which are sequentially connected; the input signal of the virtual inertia control module is used as the input signal of the voltage converter control system, and the output signal of the virtual inertia control module is used as the input signal of the virtual impedance control module; an input signal of the virtual impedance control module is used as an output signal of the virtual inertia control module, and an output signal of the virtual impedance control module is used as an input signal of the high-frequency pulse width modulator; the output signal of the high-frequency pulse width modulator is used as a switching signal of a high-switching-frequency converter of the voltage control type converter; wherein:
the virtual inertia control module is used for describing inertia characteristics considering line impedance in the simulated power grid and comprises a phase control unit and an amplitude control unit; the phase control unit comprises a virtual impedance part A, an active power calculation part and a torque equation part; the virtual impedance A part utilizes an AC test port voltage vgAC test port current igAnd a virtual impedance ZrefTo obtain a virtual voltage vsSaid virtual voltage vsAnd AC test port current igObtaining the active power P through the active power calculation partsSaid active power PsObtaining a phase signal theta of given current through the torque equation part; the amplitude control unit comprises a virtual impedance part A, a reactive power calculation part, an amplitude droop equation part and a virtual impedance part B, wherein the virtual impedance part A utilizes the voltage v of an alternating current test portgAC test port current igAnd a virtual impedance ZrefTo obtain a virtual voltage vsSaid virtual voltage vsAnd sampled current i of AC test portgObtaining a reactive power Q by the reactive power calculating partsSaid reactive power QsObtaining a virtual voltage amplitude given V through the amplitude droop equation partsrefSaid virtual voltage amplitude being given by VsrefAfter passing through the part B of the virtual impedance, an amplitude signal (i) of a dq axis of a given current is obtainedsdref,iqdref) (ii) a The phase signal of the given current and the amplitude signal of the dq axis of the given current jointly form a given signal of the virtual impedance control module;
the virtual impedance control module adopts a Norton equivalent circuit to describe the port impedance characteristic of the simulated power grid and generates a modulation signal e of the high switching frequency converterv(ii) a Wherein the virtual impedance control module mainly comprises a feedback signal meterThe device comprises a calculation unit and a voltage control unit; the feedback signal calculation unit utilizes a voltage signal v of a port to be testedgVirtual impedance ZrefAnd voltage signal i of the port to be testedgGenerating a feedback signal i in a norton equivalent circuits(ii) a The voltage control unit utilizes the output signal i of the virtual inertia control modulesrefAnd a feedback signal isGenerating a modulation signal e for a high switching frequency converterv(ii) a The high-frequency pulse width modulator modulates the modulation signal evChanging the high-frequency switching signals into corresponding high-switching frequency converters;
the input signals of the virtual inertia control module comprise given signals and sampling voltage signals v of an alternating current test portgAnd a sampled current signal i of the AC test portg(ii) a The output signal of the virtual inertia control module comprises an input given signal i of the virtual impedance control modulesrefSampling voltage signal v of AC test portgAnd a sampled current signal i of the AC test portg；
The input signal of the virtual impedance control module comprises an output current given signal i of the virtual inertia control modulesrefSampling voltage signal v of AC test portgAnd a sampled current signal i of the AC test portg(ii) a The output signal of the virtual impedance control module is an input modulation signal e of a high-frequency pulse width modulatorv；
The input signal of the high-frequency pulse width modulator is the output signal e of the voltage control unitvThe output signal of the high-frequency pulse width modulator is a switching signal of a high-switching-frequency converter;
the current converter control system is connected with the current control type converter, is used for absorbing or sending out load current of an alternating current test port, and comprises a current control module and a low-frequency pulse width modulator which are sequentially connected; wherein:
the current control module is used for generating a modulation signal of a low switching frequency converter of the current control type converter; wherein, the input signal of the current control module is AC measurementCurrent sampling signal i of test portgThe input feedback signal of the current control module is a current signal flowing through the electrical impedance network A, and the output signal of the current control module is an input modulation signal e of the low-frequency pulse width modulatori；
The low-frequency pulse width modulator is used for generating a switching signal of the low-switching-frequency converter.
Preferably, the high switching frequency comprises a dc input and an ac output, and the electrical impedance network B comprises an ac input and an ac output; wherein:
the direct current input end of the high switching frequency converter is connected with the second direct current power supply port, the alternating current output end of the high switching frequency converter is connected with the alternating current input end of the electrical impedance network B, and the alternating current output end of the electrical impedance network B is connected with the alternating current test port.
Preferably, the low switching frequency comprises a dc input and an ac output, and the electrical impedance network a comprises an ac input and an ac output; wherein:
the direct current input end of the low switching frequency converter is connected with the first direct current power supply port, the alternating current output end of the low switching frequency converter is connected with the alternating current input end of the electrical impedance network A, and the alternating current output end of the electrical impedance network A is connected with the alternating current test port.
Preferably, in the phase control unit:
the virtual impedance A part utilizes an AC test port voltage vgAC test port current igAnd a virtual impedance ZrefTo obtain a virtual voltage vsThe method comprises the following steps: sampling current i of AC test portgAnd a virtual impedance ZrefMultiplication by the AC test port voltage vgAdding to obtain an output virtual voltage signal v of a virtual impedance As；
The active power PsObtaining a phase signal θ for a given current through the torque equation portion, comprising: the parameters for setting the torque equation include: active power given P0Angular velocity given by ω0Simulated inertia J and simulated damping DpIs a parameter of the torque equation; the active power PsSubtracting the active power given P0After that, the simulated damping D is subtractedpMultiplied by the angular velocity output ω, and then added to the simulated damping DpWith said given value of angular velocity ω0And integrating the obtained value, dividing the integrated value by the simulated inertia J to obtain an output angular velocity omega of a torque equation, and integrating the output angular velocity omega to obtain a phase signal theta of the given current.
Preferably, the alternating test port current igAnd the virtual impedance ZrefThe multiplication introduces a differential calculation that is eliminated by an integral calculation of the torque equation.
Preferably, in the amplitude control unit:
the virtual impedance A part utilizes an AC test port voltage vgAC test port current igAnd a virtual impedance ZrefTo obtain a virtual voltage vsThe method comprises the following steps: AC test port current igAnd a virtual impedance ZrefMultiplication by the AC test port voltage vgAdding to obtain an output virtual voltage signal v of a virtual impedance As；
The reactive power QsObtaining a virtual voltage amplitude given V through the amplitude droop equation partsrefThe method comprises the following steps: the parameters for setting the amplitude droop equation include: given Q of reactive power0Voltage amplitude given V0And sag factor Dq(ii) a The voltage amplitude is given by V0Subtracting the droop coefficient DqGiven Q with said reactive powersAfter the product of (a), the droop coefficient D is addedqGiven Q with said reactive power0To obtain a virtual voltage amplitude given Vsref；
The virtual voltage amplitude is given by VsrefAfter passing through the part B of the virtual impedance, an amplitude signal (i) of a dq axis of a given current is obtainedsdref,iqdref) The method comprises the following steps: the virtual voltage amplitudeValue given VsrefDivided by a virtual impedance ZrefThen obtaining the amplitude signal (i) of the dq axis of the given currentsdref,iqdref)。
Preferably, the alternating test port current igAnd the virtual impedance ZrefIntroducing a differential calculation when multiplying, said virtual voltage amplitude being given by VsrefDivided by the virtual impedance ZrefIntroducing low-pass filtering calculation; the differential calculation is eliminated using the low pass filtering calculation.
Preferably, the current control module primarily controls the fundamental frequency and the low frequency content.
Preferably, the grid simulating device further comprises: any one or more of an electrical impedance network C, an electrical impedance network D, and an electrical impedance network E; wherein:
the electrical impedance network C is used for being connected between a direct current input end of the current control type converter and the first direct current power supply port;
the electrical impedance network D is used for being connected between a direct current input end of the voltage control type converter and the second direct current power supply port;
and the electrical impedance network E is used for being connected between the alternating current test port and the alternating current output end of the current control type converter after the alternating current output end of the current control type converter and the alternating current output end of the voltage control type converter are connected in parallel.
Preferably, the electrical impedance network C, the electrical impedance network D and/or the electrical impedance network E respectively employ a passive electrical impedance network for suppressing the common mode current.
According to another aspect of the invention, a virtual synchronous machine stability testing device is provided, which is implemented by using any one of the power grid simulation devices; wherein: the current control type converter and the voltage control type converter of the power grid simulation device are respectively used as two converters of the testing device, a voltage converter control system and a current converter control system of the power grid simulation device are respectively used as two controllers of the testing device, a direct current power supply port of the power grid simulation device is connected with an external power supply, and an alternating current testing port of the power grid simulation device is connected with tested equipment.
Due to the adoption of the technical scheme, compared with the prior art, the invention has the following beneficial effects:
according to the power grid simulation device and the power grid test device for testing the stability of the virtual synchronous machine, the virtual inertia amount control module eliminates discrete differential operators in part of control links by combining different control links, and the port impedance characteristic and the inertia characteristic of a medium-low frequency power grid are accurately reproduced.
The power grid simulation device and the test device for testing the stability of the virtual synchronous machine can effectively simulate the impedance characteristic and the inertia characteristic of a power grid at a low and medium frequency range, so that the stability test of a synchronous generator or a virtual synchronous machine converter under the conditions of different power grid impedances and different power grid inertias at a low and medium frequency can be efficiently realized.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
fig. 1 is a schematic structural diagram of a power grid simulation apparatus for testing stability of a virtual synchronous machine according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a low switching frequency three-phase DC/AC power electronic converter topology according to a preferred embodiment of the present invention;
FIG. 3 is a schematic diagram of a high switching frequency three-phase DC/AC power electronic converter topology according to a preferred embodiment of the present invention;
FIG. 4 is a schematic diagram of the topology of a passive electrical impedance network connected to the AC side of a low switching frequency converter in accordance with a preferred embodiment of the present invention;
FIG. 5 is a schematic diagram of the topology of a passive electrical impedance network connected to the AC side of a high switching frequency converter in accordance with a preferred embodiment of the present invention;
FIG. 6 is a schematic diagram of a simulated grid according to a preferred embodiment of the present invention;
FIG. 7 is a schematic diagram of a Noton equivalent circuit structure of a simulated power grid according to a preferred embodiment of the present invention;
FIG. 8 is a schematic diagram of a virtual inertia control link according to a preferred embodiment of the present invention;
FIG. 9 is a diagram of a phase control element according to a preferred embodiment of the present invention;
FIG. 10 is a schematic diagram of an amplitude control link according to a preferred embodiment of the present invention;
FIG. 11 is a schematic diagram of a virtual inertia digital control link according to a preferred embodiment of the present invention;
FIG. 12 is a schematic diagram of a virtual impedance control element according to a preferred embodiment of the present invention;
FIG. 13 is a schematic diagram of a current control link according to a preferred embodiment of the present invention;
FIG. 14 is a schematic of the topology of a passive electrical impedance network connected to the DC side of a low switching frequency converter in accordance with a preferred embodiment of the present invention;
fig. 15 is a schematic diagram of the topology of a passive electrical impedance network connected to the dc side of a high switching frequency converter in accordance with a preferred embodiment of the present invention;
fig. 16 is a schematic topology of a passive electrical impedance network for connecting the ac side of a voltage controlled converter, the ac side of a current controlled converter and the input side of an ac test port in accordance with a preferred embodiment of the present invention;
fig. 17 is a schematic of the topology of a passive electrical impedance network for connecting the ac side of a voltage-controlled converter, the ac side of a current-controlled converter and the input side of an ac test port according to a preferred embodiment of the present invention.
In the figure: 1-low switching frequency converter; 2-high switching frequency converter; 3-electrical impedance network a; 4-electrical impedance network B; 5-a current transformer control system; 7-virtual inertia control module; 8-a virtual impedance control module; 9-voltage converter control system; 10-a first dc power supply port; 11-an alternating current test port; 12-low switching frequency converter dc supply terminal; 13-low switching frequency converter ac terminal; 14-high switching frequency converter direct current supply end; 15-high switching frequency converter ac terminal; 16-simulated grid; 17-norton equivalent circuit of simulated grid; 18-input of electrical impedance network a; 19-output of electrical impedance network a; 20-input of electrical impedance network B; 21-output of electrical impedance network B; 22-a current control module; 23-a low frequency pulse width modulator; 24-a high frequency pulse width modulator; 25-a second dc supply port; 26-a current controlled converter; 27-a voltage controlled converter; 28-electrical impedance network C; 29-electrical impedance network D; 30-electrical impedance network E; 31-direct current input of electrical impedance network C; 32-the dc output of the electrical impedance network C; 33-direct current input of electrical impedance network D; 34-the direct current output of the electrical impedance network D; 35-alternating current input of electrical impedance network E; 36-alternating current output of electrical impedance network E; 37-a phase control unit; 38-amplitude control unit; 39-virtual impedance A; 40-torque equation; 41-amplitude droop equation; 42-virtual impedance B; 43-calculation of angular velocity equation; 44-amplitude given calculation equation.
Detailed Description
The following examples illustrate the invention in detail: the embodiment is implemented on the premise of the technical scheme of the invention, and a detailed implementation mode and a specific operation process are given. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.
Fig. 1 is a schematic structural diagram of a power grid simulation apparatus for testing stability of a virtual synchronous machine according to an embodiment of the present invention.
As shown in fig. 1, the power grid simulation apparatus for virtual synchronous machine stability test provided by this embodiment may include:
the system comprises a current control type converter, a voltage control type converter, a first direct current power supply port, a second direct current power supply port, an alternating current test port, a voltage converter control system and a current converter control system; wherein:
the port of the current control type converter comprises a direct current input end and an alternating current output end, and the port of the voltage control type converter comprises a direct current input end and an alternating current output end;
the direct current input end of the current control type converter is connected with a first direct current power supply port, the direct current input end of the voltage control type converter is connected with a second direct current power supply port, and the first direct current power supply port and the second direct current power supply port are respectively connected with an external power supply;
after the alternating current output end of the current control type converter and the alternating current output end of the voltage control type converter are connected in parallel, the alternating current output end of the current control type converter is connected with an alternating current test port; the alternating current test port outputs the characteristics of the power grid and is connected with an external converter to be tested;
the voltage control type converter comprises a high switching frequency converter and an electrical impedance network B which are connected with each other and is used for realizing the simulation of the simulated low and medium frequency power grid impedance and low frequency inertia by controlling the voltage of the alternating current test port; the electrical impedance network B is used for filtering voltage harmonic waves;
the current control type converter comprises a low switching frequency converter and an electrical impedance network A which are connected with each other, and is used for supplying or absorbing the power of the converter to be tested by sending or absorbing the fundamental frequency or low-frequency current of the alternating current test port; the impedance network A is used for filtering current harmonic waves;
the voltage converter control system comprises a virtual inertia control module, a virtual impedance control module and a high-frequency pulse width modulator which are sequentially connected; the input signal of the virtual inertia control module is used as the input signal of the voltage converter control system, and the output signal of the virtual inertia control module is used as the input signal of the virtual impedance control module; an input signal of the virtual impedance control module is used as an output signal of the virtual inertia control module, and an output signal of the virtual impedance control module is used as an input signal of the high-frequency pulse width modulator; the output signal of the high-frequency pulse width modulator is used as a switching signal of a high-switching-frequency converter of the voltage control type converter; wherein:
the virtual inertia control module is used for describing inertia characteristics considering line impedance in the simulated power grid and comprises a phase control unit and an amplitude control unit; wherein the phase control unit comprises a virtual impedance part A, an active power calculation part and a torque equation partDividing; the virtual impedance A part utilizes an AC test port voltage vgAC test port current igAnd a virtual impedance ZrefTo obtain a virtual voltage vsSaid virtual voltage vsAnd AC test port current igObtaining the active power P through the active power calculation partsSaid active power PsObtaining a phase signal theta of given current through the torque equation part; the amplitude control unit comprises a virtual impedance part A, a reactive power calculation part, an amplitude droop equation part and a virtual impedance part B, wherein the virtual impedance part A utilizes the voltage v of an alternating current test portgAC test port current igAnd a virtual impedance ZrefTo obtain a virtual voltage vsSaid virtual voltage vsAnd sampled current i of AC test portgObtaining a reactive power Q by the reactive power calculating partsSaid reactive power QsObtaining a virtual voltage amplitude given V through the amplitude droop equation partsrefSaid virtual voltage amplitude being given by VsrefAfter passing through the part B of the virtual impedance, an amplitude signal (i) of a dq axis of a given current is obtainedsdref,iqdref) (ii) a The phase signal of the given current and the amplitude signal of the dq axis of the given current jointly form a given signal of the virtual impedance control module;
the virtual impedance control module adopts a Norton equivalent circuit to describe the port impedance characteristic of the simulated power grid and generates a modulation signal e of the high switching frequency converterv(ii) a The virtual impedance control module mainly comprises a feedback signal calculation unit and a voltage control unit; the feedback signal calculation unit utilizes a voltage signal v of a port to be testedgVirtual impedance ZrefAnd voltage signal i of the port to be testedgGenerating a feedback signal i in a norton equivalent circuits(ii) a The voltage control unit utilizes the output signal i of the virtual inertia control modulesrefAnd a feedback signal isGenerating a modulation signal e for a high switching frequency converterv(ii) a The high-frequency pulse width modulator modulates the modulation signal evBecome intoA high frequency switching signal of the corresponding high switching frequency converter;
the input signals of the virtual inertia control module comprise given signals and sampling voltage signals v of an alternating current test portgAnd a sampled current signal i of the AC test portg(ii) a The output signal of the virtual inertia control module comprises an input given signal i of the virtual impedance control modulesrefSampling voltage signal v of AC test portgAnd a sampled current signal i of the AC test portg；
The input signal of the virtual impedance control module comprises an output current given signal i of the virtual inertia control modulesrefSampling voltage signal v of AC test portgAnd a sampled current signal i of the AC test portg(ii) a The output signal of the virtual impedance control module is an input modulation signal e of a high-frequency pulse width modulatorv；
The input signal of the high-frequency pulse width modulator is the output signal e of the voltage control unitvThe output signal of the high-frequency pulse width modulator is a switching signal of a high-switching-frequency converter;
the current converter control system is connected with the current control type converter, is used for absorbing or sending out load current of an alternating current test port, and comprises a current control module and a low-frequency pulse width modulator which are sequentially connected; wherein:
the current control module is used for generating a modulation signal of a low switching frequency converter of the current control type converter; wherein, the input signal of the current control module is a current sampling signal i of an alternating current test portgThe input feedback signal of the current control module is a current signal flowing through the electrical impedance network A, and the output signal of the current control module is an input modulation signal e of the low-frequency pulse width modulatori；
The low-frequency pulse width modulator is used for generating a switching signal of the low-switching-frequency converter.
The technical solutions provided by the above embodiments of the present invention are further described in detail below with reference to the accompanying drawings.
As shown in fig. 1, the power grid simulation apparatus provided by the above embodiment of the present invention mainly includes: the device comprises a current control type converter 26, a voltage control type converter 27, a first direct current power supply port 10, an electrical impedance network 28, an electrical impedance network 29, an electrical impedance network 30, a second direct current power supply port 25, an alternating current test port 11, a virtual inertia amount control module 7, a virtual impedance control module 8 and a current control module 22. It should be noted that, in fig. 1, auxiliary circuits and software modules are omitted, and addition of conventional circuit modules on the embodiment provided by the present invention also belongs to the essence of the present invention.
The current controlled converter 26 comprises a low switching frequency converter 1 and an electrical impedance network 3.
The low switching frequency converter 1 is used for absorbing or generating power of an alternating current test port on a circuit level, and may adopt, but is not limited to, any DC/AC topology structure including a three-phase two-level structure (as shown in fig. 2), and the semiconductor device may be selected, but is not limited to, a high-power fully-controlled or semi-controlled power device such as a Si IGBT.
The electrical impedance network A is a circuit structure formed by one or more passive devices such as a resistor R, an inductor L, a capacitor C and the like, and comprises at least one group of input ends and output ends, wherein the input ends and the output ends are used for being matched with the low-switching-frequency converter 1 to absorb or generate power of an alternating current test end and reduce higher harmonics of current of the alternating current test end in the system; the passive electrical impedance network employs a circuit topology including, but not limited to, that shown in fig. 3.
The voltage controlled converter 27 comprises a high switching frequency converter 2 and an electrical impedance network B.
The high switching frequency converter 2 is used for simulating the port voltage of the weak grid on a circuit level, and can adopt any DC/AC topological structure including but not limited to a three-phase two-level structure (as shown in FIG. 3), and the semiconductor device can be selected from but not limited to a high switching frequency fully-controlled or semi-controlled power device such as a SiC MOSFET.
The electrical impedance network B is a circuit structure formed by one or more passive devices such as a resistor R, an inductor L, a capacitor C and the like, and comprises at least one group of input ends and output ends, wherein the input ends and the output ends are used for matching with the high-switching-frequency converter 2 to shape the voltage of an alternating-current test end and reduce higher harmonics of the voltage of the alternating-current test end in the system; the passive electrical impedance network employs a circuit topology including, but not limited to, that shown in fig. 4.
The electrical impedance network C is a circuit structure formed by one or more passive devices such as a resistor R, an inductor L and the like, comprises at least one group of direct current input ends and direct current output ends and is used for inhibiting common mode current; the passive electrical impedance network employs a circuit topology including, but not limited to, that shown in fig. 14;
the electrical impedance network D is a circuit structure formed by one or more passive devices such as a resistor R, an inductor L and the like, comprises at least one group of direct current input ends and direct current output ends and is used for inhibiting common mode current; the passive electrical impedance network employs a circuit topology including, but not limited to, that shown in fig. 15;
the electrical impedance network E is a circuit structure formed by one or more passive devices such as a resistor R, an inductor L, a transformer and the like, comprises at least one group of alternating current input ends and alternating current output ends and is used for inhibiting common mode current; the passive electrical impedance network employs circuit topologies including, but not limited to, as shown in fig. 16 and as shown in fig. 17;
the first dc power supply port 10 comprises a positive terminal and a negative terminal, and is connected to the positive and negative terminals of the low switching frequency converter 1 or the electrical impedance network 28. The power supply method includes, but is not limited to, a direct current voltage source, a rectification circuit, and the like.
The second dc power supply port 25 comprises a positive terminal and a negative terminal, and is connected to the positive and negative terminals of the high switching frequency converter 2 or the electrical impedance network 29. The power supply method includes, but is not limited to, a direct current voltage source, a rectification circuit, and the like.
The first dc power supply port 10 and the second dc power supply port 25 may be connected to the same power supply or different power supplies.
The input end of the alternating current test port is directly connected with the alternating current output ends of the voltage control type converter and the current control type converter or is connected with the alternating current output ends of the voltage control type converter and the current control type converter through an electrical impedance network 30; the output end is connected with the converter to be tested.
The voltage controlled current transformer 27 consists of a high switching frequency current transformer 2 and an electrical impedance network B4. Wherein the high switching frequency includes a dc input and an ac output and the electrical impedance network B4 includes an ac input and an ac output. The DC input end of the high switching frequency converter 2 is connected with the second power supply port, the AC output end of the high switching frequency converter 2 is connected with the AC input end of an electrical impedance network B4, and the AC output end of an electrical impedance network B4 is connected with the AC test port.
The current-controlled converter 26 consists of a low switching frequency converter 1 and an electrical impedance network a 3. Wherein the low switching frequency includes a dc input and an ac output and the electrical impedance network a3 includes an ac input and an ac output. The direct current input end of the low switching frequency converter 1 is connected with the first power supply port, the alternating current output end of the low switching frequency converter 1 is connected with the alternating current input end of an electrical impedance network A3, and the alternating current output end of an electrical impedance network A3 is connected with the alternating current test port.
The voltage control type converter is high in switching frequency and low in power and mainly provides intermediate-frequency voltage current; the current control type converter has low switching frequency and high power and mainly provides low-frequency current.
A voltage control type converter 27 and a current control type converter 26, wherein the switching frequency of the voltage control type converter is higher, the power is lower, and the voltage control type converter mainly provides intermediate frequency voltage current; the current control type converter has low switching frequency and high power and mainly provides low-frequency current.
As shown in FIG. 8, the virtual inertia control module 7 is used for describing the inertia characteristics of the simulated power grid, and the input signal is a given signal (including P)0，Q0，V0，ω0) Sampling voltage signal v of AC test portgSampling current signal i of AC test portg(ii) a The output signal is virtualInput given signal i of analog impedance control modulesrefSampling voltage signal v of AC test portgSampling current signal i of AC test portg. The virtual inertia control module comprises a phase control unit and an amplitude control unit.
As shown in fig. 9, the phase control unit 37 includes a virtual impedance a39 section, an active power calculation section, and a torque equation 40 section. The virtual impedance A39 part obtains the port voltage of the simulated synchronous generator by using the sampling voltage, current and virtual impedance of the AC test port; the active power calculation part calculates to obtain active power by using port voltage and current of the synchronous generator; the torque equation 40 part uses the port voltage and current of the simulated synchronous machine to obtain the active power (P) and the phase (theta). The virtual impedance a39 component can be combined with the torque equation component to eliminate the digital differential component in the active power calculation using the torque equation.
As shown in fig. 10, the amplitude control unit 38 includes a reactive power calculation section, an amplitude droop equation 41 section, and a virtual impedance section. The reactive power calculating part calculates the port voltage (v) of the simulated synchronous machine by using the virtual impedance A39 containing digital differentials) Obtaining reactive power (Q) by using port voltage and current of the simulated synchronous machine, inputting the reactive power into an amplitude droop equation 41 to obtain a voltage amplitude (V), and obtaining the given value (i) of a current dq axis after the voltage amplitude passes through a virtual impedance B42sdref,isqref). The virtual impedance A part can be combined with the virtual impedance B part, and a digital differential element in the virtual impedance A is eliminated by using the virtual impedance B.
The virtual impedance A in the phase control unit and the amplitude control unit is the same virtual impedance.
Wherein, the virtual impedance A is obtained by an initial Thevenin circuit, and the virtual impedance B is obtained by an equivalent Norton circuit.
As shown in fig. 11, the phase control unit finally obtains a complete calculation equation of angular velocity, and the amplitude control unit finally obtains a given calculation equation of amplitude.
As shown in fig. 12, the virtual impedance control module 8 is used to describe impedance characteristics in the simulated power grid, where the input signal is given by the output current of the virtual inertia control module, the sampling voltage of the ac test port, and the sampling current of the ac test port; the output signal is the input signal of the high-frequency pulse width modulation.
The input given signal of the current control module 22 is a sampled current signal of the alternating current test port; the input feedback signal is the current flowing through the electrical impedance network a 3; the output signal is the modulation signal of the low-frequency pulse width modulator.
The technical details of the power grid simulation apparatus in the abc stationary coordinate system will be described below by taking the embodiments described in fig. 1, 4 and 5 as examples.
The control system of the power grid simulation device comprises a control system of a voltage control type converter and a control system of a current control type converter.
Specifically, the control system of the voltage control type converter mainly includes a virtual inertia control module 7, a virtual impedance control module 8 and a high-frequency pulse width modulator 24, wherein:
in a first step, given a model of the simulation grid, the series impedance Z in the simulation grid as shown in fig. 6 is obtainedref(ii) a Detecting the current signal (i) of the AC test port by a sampling circuitg) And voltage signal (v)g)；
In the second step, the port voltage signals of the synchronous generator as shown in fig. 6 are:
vs＝vg+igZref (1)
third, by the port voltage signal (i) of the synchronous generators) And voltage signal (v)g) Obtaining the active power (P) and the reactive power (Q) of the ports of the synchronous machine as follows:
P＝vsaiga+vsbigb+vscigc (2)
fourthly, the active power (P) of the port of the synchronous machine is given through the active power (P)0) Angular velocity given by (ω)0) Simulated inertia (J), damping coefficient (D)p) And torqueThe equation, resulting in angular velocity (ω) and phase (θ) is as follows:
θ＝∫ωdt (4)
the fifth step, combining the torque equation and the virtual impedance a, and eliminating the differential term in the virtual impedance a by using the torque equation to obtain the angular velocity calculation equation 43 shown in fig. 11, where the specific expression is as follows:
sixth, through the port voltage signal (i) of the synchronous generators) And voltage signal (v)g) And obtaining the reactive power (Q) of the port of the synchronous machine as follows:
seventh step, through the reactive power (Q) of the synchronous machine port, the reactive power is given (Q)0) Voltage amplitude given (V)0) Reactive sag factor (D)q) And obtaining the voltage amplitude (V) of the output port of the synchronous machine according to an amplitude droop equation as follows:
V＝V0-Dq(Q-Q0) (7)
in the eighth step, the circuit shown in FIG. 6 is equivalently processed into the circuit shown in FIG. 7, wherein the current signal of the current source is vsref/ZrefParallel impedance of Zref. As shown in fig. 7, the given current signal of an ideal current source can be obtained as:
transforming the expression coordinate to the rotating coordinate system to obtain the given value of the current source in the rotating coordinate system as follows:
the ninth step, combining the virtual impedance a, the amplitude droop equation and the virtual impedance B, and using the virtual impedance B to eliminate the differential term in the virtual impedance a, so as to obtain an amplitude given calculation equation 44 as shown in fig. 11, where the specific expression is as follows:
wherein the content of the first and second substances,
the tenth step, using the phase (theta) obtained in the fourth step and the given current source in the rotating coordinate system obtained in the seventh step to obtain the given current source (i) in the natural coordinate systemsabcref)：
The tenth step is that a voltage signal (v) of the AC test port is detected by a sampling circuitg) And a current signal (i)g) The feedback current signal through the current source as shown in fig. 7 is obtained as:
from this, the actual feedback signal (i) of the virtual impedance control block shown in FIG. 8 can be obtainedz): voltage signal (v) of AC test portg) Divided by the parallel impedance (Z)ref) Then with the current signal (i) of the AC test portg) And (4) adding.
In the twelfth step, the given current signal flowing through the impedance shown in fig. 7 is subtracted from the actual feedback current signal to obtain the input signal of the voltage control unit.
A thirteenth step of modulating the modulated signal (e) outputted from the voltage control unitv) The switching signal of the switching tube is obtained by a high-frequency pulse width modulator 24.
Specifically, the control system of the low switching frequency converter mainly comprises a current control module 22 and a low frequency pulse width modulator 23, wherein:
firstly, obtaining the current i of an alternating current test port through a sampling circuitgTest the current (i) of the portg) As input given signals for the current transformer control system 5 as shown in fig. 13;
secondly, obtaining the current i of the output port of the electrical impedance network A3 through a sampling circuitg_iCurrent (i) at output port of electrical impedance network A3g_i) Is the feedback input signal of the current transformer control system 5 as shown in fig. 13;
thirdly, the current control module 22 adopts a proportional resonance control link to realize the static-error-free control, and the resonance frequency of the resonance control link in the proportional resonance control link is the fundamental frequency of the system;
in the fourth step, the output of the current control module 22 is a modulation signal eiModulating signal eiGenerating a switching signal of a switching device in the low switching frequency converter after passing through the low frequency modulator 23;
an embodiment of the present invention provides a virtual synchronous machine stability testing apparatus, which is implemented by using a power grid simulation apparatus according to any one of the above embodiments of the present invention; wherein: the current control type converter and the voltage control type converter of the power grid simulation device are respectively used as two converters of the testing device, a voltage converter control system and a current converter control system of the power grid simulation device are respectively used as two controllers of the testing device, a direct current power supply port of the power grid simulation device is connected with an external power supply, and an alternating current testing port of the power grid simulation device is connected with tested equipment.
The power grid simulation device and the test device for testing the stability of the virtual synchronous machine provided by the embodiments of the invention are power grid simulation devices capable of simulating the impedance characteristic and the inertia characteristic of a power grid. The method mainly comprises the following steps: the device comprises a voltage control type converter, a current control type converter, a virtual inertia amount control module, a virtual impedance control module, a voltage control link, a current control link and an electrical impedance network. The voltage control type converter adopts a virtual inertia control module and a virtual impedance control module to realize the port characteristics of the simulated power grid, and has higher switching frequency; the current control type converter absorbs or generates port load current of a simulated power grid by adopting a current control link, and has lower switching frequency; the alternating current sides of the two converters are connected in parallel and then are directly connected with the port of the simulated power grid, or are connected with the port of the simulated power grid through an electrical impedance network. The virtual inertia amount control module eliminates discrete differential operators in part of control links by combining different control links together. The power grid simulation device and the test device for testing the stability of the virtual synchronous machine provided by the embodiment of the invention can effectively simulate the impedance characteristic and the inertia characteristic of a power grid in a low and medium frequency range, so that the stability test of a synchronous generator or a virtual synchronous machine converter under the conditions of different power grid impedances and different power grid inertias is efficiently realized.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.
Claims (10)
1. A power grid simulation device for testing the stability of a virtual synchronous machine is characterized by comprising a current control type converter, a voltage control type converter, a first direct current power supply port, a second direct current power supply port, an alternating current test port, a voltage converter control system and a current converter control system; wherein:
the ports of the current control type converter comprise a direct current input end and an alternating current output end, and the ports of the voltage control type converter comprise a direct current input end and an alternating current output end;
the direct current input end of the current control type converter is connected with the first direct current power supply port, the direct current input end of the voltage control type converter is connected with the second direct current power supply port, and the first direct current power supply port and the second direct current power supply port are respectively connected with an external power supply;
the alternating current output end of the current control type converter is connected with the alternating current test port after being connected in parallel with the alternating current output end of the voltage control type converter; the alternating current test port outputs the characteristics of a power grid and is connected with an external converter to be tested;
the voltage control type converter comprises a high switching frequency converter and an electrical impedance network B which are connected with each other, and is used for realizing simulation of the simulated low and medium frequency power grid impedance and low frequency inertia by controlling the voltage of the alternating current test port; the electrical impedance network B is used for filtering voltage harmonic waves;
the current control type converter comprises a low switching frequency converter and an electrical impedance network A which are connected with each other, and is used for supplying or absorbing the power of the converter to be tested by sending or absorbing the fundamental frequency or low-frequency current of an alternating current test port; wherein, the electrical impedance network A is used for filtering current harmonic waves;
the voltage converter control system comprises a virtual inertia control module, a virtual impedance control module and a high-frequency pulse width modulator which are sequentially connected; the input signal of the virtual inertia control module is used as the input signal of the voltage converter control system, and the output signal of the virtual inertia control module is used as the input signal of the virtual impedance control module; an input signal of the virtual impedance control module is used as an output signal of the virtual inertia control module, and an output signal of the virtual impedance control module is used as an input signal of the high-frequency pulse width modulator; the output signal of the high-frequency pulse width modulator is used as a switching signal of a high-switching-frequency converter of the voltage control type converter; wherein:
the virtual inertia control module is used for describing inertia characteristics considering line impedance in the simulated power grid and comprises a phase control unit and an amplitude control unit; the phase control unit comprises a virtual impedance part A, an active power calculation part and a torque equation part; the virtual impedance A part utilizes an AC test port voltage vgAC test port current igAnd a virtual impedance ZrefTo obtain a virtual voltage vsSaid virtual voltage vsAnd AC test port current igObtaining the active power P through the active power calculation partsSaid active power PsObtaining a phase signal theta of given current through the torque equation part; the amplitude control unit comprises a virtual impedance part A, a reactive power calculation part, an amplitude droop equation part and a virtual impedance part B, wherein the virtual impedance part A utilizes the voltage v of an alternating current test portgAC test port current igAnd a virtual impedance ZrefTo obtain a virtual voltage vsSaid virtual voltage vsAnd sampled current i of AC test portgObtaining a reactive power Q by the reactive power calculating partsSaid reactive power QsObtaining a virtual voltage amplitude given V through the amplitude droop equation partsrefSaid virtual voltage amplitude being given by VsrefAfter passing through the part B of the virtual impedance, an amplitude signal (i) of a dq axis of a given current is obtainedsdref,iqdref) (ii) a The phase signal of the given current and the amplitude signal of the dq axis of the given current jointly form a given signal of the virtual impedance control module;
the virtual impedance control module adopts a Norton equivalent circuit to describe the port impedance characteristic of the simulated power grid and generates a modulation signal e of the high switching frequency converterv(ii) a The virtual impedance control module mainly comprises a feedback signal calculation unit and a voltage control unit; the feedback signal calculation unit utilizes a voltage signal v of a port to be testedgVirtual impedance ZrefAnd a port under testVoltage signal igGenerating a feedback signal i in a norton equivalent circuits(ii) a The voltage control unit utilizes the output signal i of the virtual inertia control modulesrefAnd a feedback signal isGenerating a modulation signal e for a high switching frequency converterv(ii) a The high-frequency pulse width modulator modulates the modulation signal evChanging the high-frequency switching signals into corresponding high-switching frequency converters;
the input signals of the virtual inertia control module comprise given signals and sampling voltage signals v of an alternating current test portgAnd a sampled current signal i of the AC test portg(ii) a The output signal of the virtual inertia control module comprises an input given signal i of the virtual impedance control modulesrefSampling voltage signal v of AC test portgAnd a sampled current signal i of the AC test portg；
The input signal of the virtual impedance control module comprises an output current given signal i of the virtual inertia control modulesrefSampling voltage signal v of AC test portgAnd a sampled current signal i of the AC test portg(ii) a The output signal of the virtual impedance control module is an input modulation signal e of a high-frequency pulse width modulatorv；
The input signal of the high-frequency pulse width modulator is the output signal e of the voltage control unitvThe output signal of the high-frequency pulse width modulator is a switching signal of a high-switching-frequency converter;
the current converter control system is connected with the current control type converter, is used for absorbing or sending out load current of an alternating current test port, and comprises a current control module and a low-frequency pulse width modulator which are sequentially connected; wherein:
the current control module is used for generating a modulation signal of a low switching frequency converter of the current control type converter; wherein, the input signal of the current control module is a current sampling signal i of an alternating current test portgThe input feedback signal of the current control module is a current signal flowing through the electrical impedance network A, and the output signal of the current control module isInput modulation signal e of the low frequency pulse width modulatori；
The low-frequency pulse width modulator is used for generating a switching signal of the low-switching-frequency converter.
2. The grid simulating device for testing the stability of the virtual synchronous machine according to claim 1, wherein the high switching frequency includes a direct current input terminal and an alternating current output terminal, and the electrical impedance network B includes an alternating current input terminal and an alternating current output terminal; wherein:
the direct current input end of the high switching frequency converter is connected with the second direct current power supply port, the alternating current output end of the high switching frequency converter is connected with the alternating current input end of the electrical impedance network B, and the alternating current output end of the electrical impedance network B is connected with the alternating current test port.
3. The grid simulating device for testing the stability of the virtual synchronous machine according to claim 1, wherein the low switching frequency includes a direct current input terminal and an alternating current output terminal, and the electrical impedance network a includes an alternating current input terminal and an alternating current output terminal; wherein:
the direct current input end of the low switching frequency converter is connected with the first direct current power supply port, the alternating current output end of the low switching frequency converter is connected with the alternating current input end of the electrical impedance network A, and the alternating current output end of the electrical impedance network A is connected with the alternating current test port.
4. The grid simulation device for the virtual synchronous machine stability test according to claim 1, wherein the phase control unit comprises:
the virtual impedance A part utilizes an AC test port voltage vgAC test port current igAnd a virtual impedance ZrefTo obtain a virtual voltage vsThe method comprises the following steps: sampling current i of AC test portgAnd a virtual impedance ZrefMultiplication by the AC test port voltage vgAdding to obtain the output virtual voltage of the virtual impedance ASignal vs；
The active power PsObtaining a phase signal θ for a given current through the torque equation portion, comprising: the parameters for setting the torque equation include: active power given P0Angular velocity given by ω0Simulated inertia J and simulated damping DpIs a parameter of the torque equation; the active power PsSubtracting the active power given P0After that, the simulated damping D is subtractedpMultiplied by the angular velocity output ω, and then added to the simulated damping DpWith said given value of angular velocity ω0And integrating the obtained value, dividing the integrated value by the simulated inertia J to obtain an output angular velocity omega of a torque equation, and integrating the output angular velocity omega to obtain a phase signal theta of the given current.
5. The grid simulator for virtual synchronous machine stability testing according to claim 4, wherein the alternating current test port current igAnd the virtual impedance ZrefThe multiplication introduces a differential calculation that is eliminated by an integral calculation of the torque equation.
6. The power grid simulation device for the virtual synchronous machine stability test according to claim 1, wherein in the amplitude control unit:
the virtual impedance A part utilizes an AC test port voltage vgAC test port current igAnd a virtual impedance ZrefTo obtain a virtual voltage vsThe method comprises the following steps: AC test port current igAnd a virtual impedance ZrefMultiplication by the AC test port voltage vgAdding to obtain an output virtual voltage signal v of a virtual impedance As；
The reactive power QsObtaining a virtual voltage amplitude given V through the amplitude droop equation partsrefThe method comprises the following steps: the parameters for setting the amplitude droop equation include: given Q of reactive power0Voltage amplitude given V0And lowerCoefficient of sag Dq(ii) a The voltage amplitude is given by V0Subtracting the droop coefficient DqGiven Q with said reactive powersAfter the product of (a), the droop coefficient D is addedqGiven Q with said reactive power0To obtain a virtual voltage amplitude given Vsref；
The virtual voltage amplitude is given by VsrefAfter passing through the part B of the virtual impedance, an amplitude signal (i) of a dq axis of a given current is obtainedsdref,iqdref) The method comprises the following steps: the virtual voltage amplitude is given by VsrefDivided by a virtual impedance ZrefThen obtaining the amplitude signal (i) of the dq axis of the given currentsdref,iqdref)。
7. The grid simulator for virtual synchronous machine stability testing according to claim 6, wherein the alternating current test port current igAnd the virtual impedance ZrefIntroducing a differential calculation when multiplying, said virtual voltage amplitude being given by VsrefDivided by the virtual impedance ZrefIntroducing low-pass filtering calculation; the differential calculation is eliminated using the low pass filtering calculation.
8. The grid simulating device for the virtual synchronous machine stability test according to any one of claims 1 to 7, further comprising: any one or more of an electrical impedance network C, an electrical impedance network D, and an electrical impedance network E; wherein:
the electrical impedance network C is used for being connected between a direct current input end of the current control type converter and the first direct current power supply port;
the electrical impedance network D is used for being connected between a direct current input end of the voltage control type converter and the second direct current power supply port;
and the electrical impedance network E is used for being connected between the alternating current test port and the alternating current output end of the current control type converter after the alternating current output end of the current control type converter and the alternating current output end of the voltage control type converter are connected in parallel.
9. The power grid simulation device for the virtual synchronous machine stability test according to claim 8, wherein the electrical impedance network C, the electrical impedance network D and/or the electrical impedance network E respectively adopt a passive electrical impedance network for suppressing common mode current.
10. A virtual synchronous machine stability testing device, which is implemented by using the power grid simulation device of any one of claims 1 to 9; wherein: the current control type converter and the voltage control type converter of the power grid simulation device are respectively used as two converters of the testing device, a voltage converter control system and a current converter control system of the power grid simulation device are respectively used as two controllers of the testing device, a direct current power supply port of the power grid simulation device is connected with an external power supply, and an alternating current testing port of the power grid simulation device is connected with tested equipment.
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| CN104716886A (en) * | 2015-03-31 | 2015-06-17 | 西安交通大学 | Virtual impedance voltage converter-based control method of virtual synchronous motor |
| CN111277001A (en) * | 2020-03-14 | 2020-06-12 | 福建工程学院 | Fan grid-connected control method based on virtual synchronous generator parameter adaptive control |
| CN111541274A (en) * | 2020-05-27 | 2020-08-14 | 燕山大学 | Island microgrid control strategy based on virtual synchronous generator characteristics |
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| CN104716886A (en) * | 2015-03-31 | 2015-06-17 | 西安交通大学 | Virtual impedance voltage converter-based control method of virtual synchronous motor |
| CN111277001A (en) * | 2020-03-14 | 2020-06-12 | 福建工程学院 | Fan grid-connected control method based on virtual synchronous generator parameter adaptive control |
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