CN108959780B - Large signal simulation model of single-phase power electronic transformer - Google Patents
Large signal simulation model of single-phase power electronic transformer Download PDFInfo
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- CN108959780B CN108959780B CN201810737971.2A CN201810737971A CN108959780B CN 108959780 B CN108959780 B CN 108959780B CN 201810737971 A CN201810737971 A CN 201810737971A CN 108959780 B CN108959780 B CN 108959780B
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Abstract
The invention relates to the field of power system transformer simulation, in particular to a large-signal simulation model of a single-phase power electronic transformer, and aims to improve the simulation speed. The simulation model comprises a cascade H-bridge converter equivalent large signal model and a dual-active bridge converter equivalent large signal model. The equivalent large-signal model of the cascaded H-bridge converter consists of a cascaded H-bridge converter module and a first controlled voltage source H 1 A first controlled current source S 1 And a support capacitor C 1 Forming; the cascaded H-bridge converter module comprises 4 input signals and 4 output terminals; the equivalent large-signal model of the double-active-bridge converter consists of a double-active-bridge converter module and an equivalent resistor R eq Equivalent inductance L eq And an output side capacitor C 2 A second controlled voltage source H 2 And a second controlled current source S 2 Forming; the dual active bridge converter module comprises 4 input signals and 4 output terminals. The invention can accelerate the simulation speed of the single-phase power electronic transformer when being disturbed by large signals such as load switching or faults.
Description
Technical Field
The invention relates to the field of power system transformer simulation, in particular to a large-signal simulation model of a single-phase power electronic transformer.
Background
In order to meet the application requirements of medium and high voltage distribution networks in future smart Power grids, research is conducted at home and abroad on various Power Electronic Transformers (PET). Besides the functions of voltage grade conversion and electrical isolation of the traditional transformer, the PET can also realize the functions of bidirectional flow of tide, power quality control, automatic protection of the device and the like. In consideration of the voltage withstanding level of power semiconductor devices, the PET currently used in medium and high voltage distribution networks is generally composed of a cascade of multiple power modules, each of which includes an H-bridge converter and a dual active bridge converter, and generates a dc voltage by connecting the output sides of the power modules in parallel for use by a user. Nowadays, the cascade type PET that has been applied to the power system can be classified into single-phase PET and three-phase PET, and the three-phase PET can be composed of three single-phase PET in star or corner connection.
For the design of a single-phase power electronic transformer, the stability is the most basic, most core and most complex part. In the actual operation process, interaction exists between all the cascade power modules, and the system may not work at a preset stable working point when being disturbed by large signals such as load switching or faults, and other abnormal phenomena such as voltage drop and oscillation of the direct-current bus occur. By predicting the stability of the system in advance by using computer simulation in the design stage, the system performance and the operation reliability can be improved.
The method commonly used in the prior art is as follows: and (4) constructing the simulation model by adopting the simulation model and a method of element 1 to element 1 in the actual circuit. However, the system scale is huge due to a large number of cascaded power modules, a large amount of time is required for calculation by using simulation software, and the calculation may not converge, so that the simulation cannot be performed. Therefore, the establishment of a large-signal simulation model of the single-phase power electronic transformer is important for analyzing the operation stability of the system and accelerating the simulation speed of the system.
In the prior art, a method for constructing a large-signal simulation model adopts models such as a gyrator. The large signal simulation model of the single-phase power electronic transformer mainly comprises the following components: the cascade H-bridge converter and the double-active-bridge converter are equivalent to a large-signal model. For an equivalent large-signal model of a cascaded H-bridge converter, the existing scheme is generally based on a power balance principle, power loss in the converter is ignored, a gyrator equivalent model is adopted, an alternating current input side and a direct current output side of the converter are equivalent to two controlled current sources, control signals of the controlled current sources on the output side are output from a capacitor voltage single closed-loop control system, the simulation speed of the model is high, but a double closed-loop control system in an entity simulation model cannot be simulated; the double-active-bridge converter generally comprises an LC resonance type and a non-resonance type, when the switching frequency of a power semiconductor in the LC resonance type double-active-bridge converter is the same as the frequency of an LC resonance loop in the converter, an open-loop control mode of outputting 50% duty ratio square wave voltage can be adopted for power transmission, the control mode is simple and convenient, and when an equivalent large-signal model of the double-active-bridge converter is established by adopting a gyrator, a control signal of a controlled current source in a Cheng Qiude gyrator model through a complex computer is often needed. Besides a gyrator model, a discrete domain model and a large signal model based on a modern control theory can also be adopted in the existing scheme, the simulation precision is high, but the model is complex, and the analysis form of the system in the time domain cannot be obtained.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a large-signal simulation model of a single-phase power electronic transformer, which improves the simulation speed of the single-phase power electronic transformer when the single-phase power electronic transformer is disturbed by large signals such as load switching or faults.
In one aspect of the invention, a large-signal simulation model of a single-phase power electronic transformer is provided, wherein the single-phase power electronic transformer comprises N power modules, and each power module consists of an H-bridge converter and a double-active-bridge converter; the input sides of N H-bridge converters are cascaded, and the output side of each H-bridge converter is connected with a supporting capacitor C in parallel 1 '; each double-active-bridge converter comprises a resonant circuit consisting of a capacitor and a high-frequency transformer, and the resonant circuit is controlled by adopting square wave voltage with the open-loop duty ratio of 50%; the output side of each double-active-bridge converter is connected with an output side capacitor C in parallel 2 '; the output sides of the N double-active-bridge converters are connected in parallel;
the simulation model comprises: the cascade H-bridge converter equivalent large signal model and the double-active-bridge converter equivalent large signal model connected with the cascade H-bridge converter equivalent large signal model are connected with the cascade H-bridge converter equivalent large signal model;
the cascade H-bridge converter equivalent large signal model is used for simulating N H-bridge converters in the single-phase power electronic transformer;
the double-active-bridge converter equivalent large-signal model is used for simulating N double-active-bridge converters in the single-phase power electronic transformer.
Preferably, the single-phase power electronic transformer further comprises: a voltage current double closed loop control system;
accordingly, the simulation model further comprises: a voltage-current double closed-loop control model;
the voltage and current double-closed-loop control model is used for simulating the voltage and current double-closed-loop control system.
Preferably, the cascade H-bridge converter equivalent large signal model includes: cascaded H-bridge converter module and first controlled voltage source H 1 A first controlled current source S 1 And a support capacitor C 1 ；
Wherein, the first and the second end of the pipe are connected with each other,
the cascaded H-bridge converter module comprises: 4 input signals u g 、i g 、U C1 N, and 4 output terminals a 1 、b 1 、c 1 、d 1 ；
u g For the collected AC voltage reference signal, i, output by the voltage-current double closed-loop control model g For the collected network side current signal in the simulation model, U C1 For the collected supporting capacitor C 1 N is the number of the cascaded power modules of the single-phase power electronic transformer;
a 1 、b 1 respectively connected with the first controlled voltage source H 1 The positive and negative control terminals of the anode and cathode are connected; c. C 1 、d 1 Are respectively connected with the first controlled current source S 1 The positive and negative control terminals of the anode and cathode are connected;
the first controlled voltage source H 1 The two voltage terminals of the transformer are connected with a power grid; the first controlledCurrent source S 1 Positive and negative output terminals of the capacitor and the supporting capacitor C 1 The positive electrode and the negative electrode are connected.
Preferably, the equivalent large-signal model of the dual-active-bridge converter comprises:
double-active-bridge converter module and equivalent resistor R eq Equivalent inductance L eq Output side capacitor C 2 A second controlled voltage source H 2 And a second controlled current source S 2 ；
Wherein, the first and the second end of the pipe are connected with each other,
the dual active bridge converter module comprises 4 input signals I cur 、U dc K, N, and 4 output terminals a 2 、b 2 、c 2 、d 2 ；
U dc For the collected output side capacitance C 2 DC voltage signals at both ends, I cur For the collected current to flow through the equivalent resistance R eq K is the primary and secondary side voltage transformation ratio of a high-frequency transformer in a single double-active-bridge converter of the single-phase power electronic transformer, and N is the number of cascaded power modules of the single-phase power electronic transformer;
a 2 、b 2 are respectively connected with the second controlled voltage source H 2 The positive and negative control terminals of (2) are connected; c. C 2 、d 2 Respectively with the second controlled current source S 2 The positive and negative control terminals of (2) are connected;
the second controlled voltage source H 2 The positive voltage terminal of (2) is connected with the equivalent resistor R in sequence eq The equivalent inductor L eq After being connected in series with the supporting capacitor C 1 The positive electrode of (1) is connected; the second controlled voltage source H 2 And the support capacitor C 1 The negative electrode of (1) is connected; the second controlled current source S 2 Respectively with the output side capacitor C 2 The positive electrode and the negative electrode are connected.
Preferably, the support capacitor C 1 The values of (A) are:
C 1 ＝C 1 ′
wherein, C 1 ' is a support capacitor connected in parallel with the output side of a single H-bridge converter in the single-phase power electronic transformer.
Preferably, the output terminal a of the cascaded H-bridge converter module 1 、b 1 The output voltage control signal is:
u ab1 ＝u g
wherein u is g And the reference signal is an alternating voltage reference signal output by the double closed-loop control model.
Preferably, the output terminal c of the cascaded H-bridge converter module 1 、d 1 The output current control signal is:
wherein u is g An AC voltage reference signal, i, output by the double closed-loop control model g For the collected network side current signals in the simulation model, N is the number of the single-phase power electronic transformer cascade power modules, U C1 For the support capacitance C in the collected simulation model 1 The voltage signal of (2).
Preferably, the output side capacitance C 2 The value of is N double-active-bridge converter output side capacitors C in the single-phase power electronic transformer 2 ' of the total volume.
Preferably, the equivalent resistance R eq The values of (A) are:
wherein R is loss And converting the resistance values of the primary and secondary coils at the high-voltage side for the high-frequency transformer in a single double-active-bridge converter in the single-phase power electronic transformer.
Preferably, the equivalent inductance L eq The values of (A) are:
wherein L is res The inductance value is measured at the primary winding of the high-frequency transformer when the secondary winding of the high-frequency transformer in a single double-active-bridge converter in the single-phase power electronic transformer is short-circuited.
Preferably, the output terminal a of the dual active bridge converter module 2 、b 2 The output voltage control signal is:
U ab2 ＝kU dc
k is the primary and secondary side voltage transformation ratio of the high-frequency transformer in the single double-active bridge converter of the single-phase power electronic transformer, and U dc For the acquired output side capacitance C in the simulation model 2 A direct current voltage signal across.
Preferably, the output terminal c of the dual active bridge converter module 2 、d 2 The output current control signal is:
I cd2 ＝kNI cur
wherein k is the primary-side and secondary-side voltage transformation ratio of a high-frequency transformer in a single double-active-bridge converter in the single-phase power electronic transformer, N is the number of cascaded power modules of the single-phase power electronic transformer, and I cur For the acquired equivalent resistance R flowing through the simulation model eq The current signal of (2).
Compared with the prior art, the invention has the following beneficial effects:
compared with the existing 1-to-1 simulation model, the single-phase power electronic transformer simulation model avoids a large-scale cascade module, reduces the calculation time of simulation software, and improves the simulation speed of the single-phase power electronic transformer when being disturbed by large signals such as load switching or faults; compared with the prior art that a large-signal simulation model is built by adopting a gyrator equivalent model, the system is simpler, and the analytic form of the system in the time domain can be solved.
Drawings
FIG. 1 is a schematic diagram of a single-phase power electronic transformer according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of the structure of a dual closed-loop control system according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a large-signal simulation model of a single-phase power electronic transformer according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of the structure of the equivalent large signal model of the cascaded H-bridge converter and the equivalent large signal model of the dual-active-bridge converter in the embodiment of the invention;
FIG. 5 is a graph showing the AC side voltage u simulated by the current 1-to-1 simulation model when the load is suddenly increased by 500kW/1.125 Ω at 0.3s from the no-load state sa Ac side current i g And a support capacitor C 1 Voltage U on C1 And an output side DC voltage U dc The waveform of (a);
FIG. 6 is a graph showing the simulated AC side voltage u of the large-signal simulation model of the single-phase power electronic transformer when the load is suddenly increased by 500kW/1.125 Ω at 0.3s sa Ac side current i g And a support capacitor C 1 Voltage U on C1 And an output side DC voltage U dc The waveform of (2).
Detailed Description
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention.
Fig. 1 is a schematic diagram of a single-phase power electronic transformer. Fig. 2 is a schematic diagram of the structure of the double closed-loop control system. As shown in fig. 1, the unidirectional power electronic transformer includes N power modules, and each power module is composed of an H-bridge converter and a dual-active-bridge converter; the input sides of N H-bridge converters are cascaded, and the output side of each H-bridge converter is connected with a supporting capacitor C in parallel 1 '; each double-active-bridge converter comprises a capacitor C r1 、C r2 The resonant circuit is formed by a high-frequency transformer and is controlled by square wave voltage with the open-loop duty ratio of 50 percent; the output side of each double-active-bridge converter is connected with output side electricity in parallelContainer C 2 '; the output sides of the N double-active-bridge converters are connected in parallel. In addition, a dual closed loop control system, as shown in fig. 2, is included for controlling the H-bridge converter. The control system is a traditional double closed-loop control system with an outer capacitor voltage ring and an inner current ring on an output side, wherein U is dc_ref For controlling the DC voltage reference, U, at the output side of a dual active bridge converter in a system dc Is the DC voltage, u, at the output side of the dual active bridge converter of FIG. 1 sa For the mains voltage, i g_ref For controlling the reference value of the current of the power grid side behind the capacitor voltage outer loop PI controller in the system g Is the current on the grid side, u, of FIG. 1 g Is an output alternating voltage reference signal.
In the prior art, a computer simulation model is generally constructed by adopting a simulation model and a method of actual circuit elements 1 to 1, and the obtained model structure is the same as that of fig. 1 and 2.
The parameters of the single-phase power electronic transformer in the embodiment of the invention are as follows:
single phase cross current side voltage u sa ：10kV；
Bridge arm filter inductance L g ：10mH；
Number of cascaded power modules N:6;
support capacitor C 1 ′：2mF；
Rated voltage U of support capacitor C1 ：1600V；
Double-active-bridge converter resonant capacitor C r1 ：90μF；
Double-active-bridge converter resonant capacitor C r2 ：90μF；
Leakage inductance L of high-frequency transformer res ：62.5μH；
Resonance frequency f:5kHz;
output side capacitance C2' of the dual active bridge converter: 4mF;
rated voltage U at output side of double-active-bridge converter dc ：750V；
High-frequency transformer coil resistor R loss ：65mΩ；
Triangular carrier frequency: 800Hz;
modulation mode of cascaded H-bridge converter: carrier phase shift
Load resistance R L ：1.125Ω
Fig. 3 is a schematic configuration diagram of an embodiment of a large-signal simulation model of a single-phase power electronic transformer according to the invention. As shown in fig. 3, the large-signal simulation model 10 of the single-phase power electronic transformer of the present embodiment includes: the system comprises a cascade H-bridge converter equivalent large signal model 11, a double-active-bridge converter equivalent large signal model 12 connected with the cascade H-bridge converter equivalent large signal model, and a voltage-current double closed-loop control model 13.
The cascade H-bridge converter equivalent large signal model 11 is used for simulating N H-bridge converters in the single-phase power electronic transformer; the double-active-bridge converter equivalent large-signal model 12 is used for simulating N double-active-bridge converters in the single-phase power electronic transformer; the voltage-current double closed-loop control model 13 is used for simulating a voltage-current double closed-loop control system of the H-bridge converter.
Fig. 4 is a schematic configuration diagram of an equivalent large-signal model of the cascaded H-bridge converter and an equivalent large-signal model of the dual-active bridge converter in the present embodiment.
As shown in fig. 4, the equivalent large-signal model of the cascaded H-bridge converter in this embodiment includes: cascaded H-bridge converter module and first controlled voltage source H 1 A first controlled current source S 1 And a support capacitor C 1 。
The cascaded H-bridge converter module comprises: 4 input signals u g 、i g 、U C1 N, and 4 output terminals a 1 、b 1 、c 1 、d 1 。
u g For the alternating voltage reference signal, i, output by the acquired voltage-current double closed-loop control model g For the collected network side current signal, U, in the simulation model C1 For collected supporting capacitance C 1 N is the number of cascaded power modules of the single-phase power electronic transformer.
a 1 、b 1 Respectively connected with a first controlled voltage source H 1 The positive and negative control terminals of the anode and cathode are connected; c. C 1 、d 1 Respectively connected with a first controlled current source S 1 Positive and negative electrode control terminalConnecting; first controlled voltage source H 1 The two voltage terminals of the transformer are connected with a power grid; a first controlled current source S 1 The positive and negative output terminals of the capacitor are respectively connected with the supporting capacitor C 1 The positive electrode and the negative electrode are connected.
Specifically, the support capacitance C can be calculated according to equation (1) 1 The value of (c):
C 1 ＝C 1 ′ (1)
wherein, C 1 ' supporting capacitors connected in parallel at the output side of a single H-bridge converter in a single-phase power electronic transformer, according to the parameters in the embodiment, C can be obtained 1 ＝2mF；
Specifically, the output terminal a of the cascaded H-bridge converter module may be calculated according to equation (2) 1 、b 1 Output voltage control signal:
u ab1 ＝u g (2)
wherein u is g The reference signal is an alternating voltage reference signal output by the double closed-loop control model.
Specifically, the output terminal c of the cascaded H-bridge converter module may be calculated according to equation (3) 1 、d 1 Output current control signal:
wherein u is g Reference signal of AC voltage, i, for the output of a double closed-loop control model g For the collected network side current signals in the simulation model, N is the number of cascaded power modules of the single-phase power electronic transformer, U C1 For the support capacitance C in the collected simulation model 1 The voltage signal of (2).
As shown in fig. 4, the equivalent large-signal model of the dual-active-bridge converter in this embodiment includes: double-active-bridge converter module and equivalent resistor R eq Equivalent inductance L eq And an output side capacitor C 2 A second controlled voltage source H 2 And a second controlled current source S 2 。
The dual active bridge converter module comprises 4 input signalsI cur 、U dc K, N, and 4 output terminals a 2 、b 2 、c 2 、d 2 。
U dc For the collected output side capacitance C 2 DC voltage signals at both ends, I cur For the collected flow passing through the equivalent resistance R eq K is the primary and secondary side voltage transformation ratio of a high-frequency transformer in a single double-active bridge converter of the single-phase power electronic transformer, and N is the number of cascaded power modules of the single-phase power electronic transformer.
a 2 、b 2 Respectively connected with a second controlled voltage source H 2 The positive and negative control terminals of (2) are connected; c. C 2 、d 2 Respectively connected with a second controlled current source S 2 The positive and negative control terminals of the anode and cathode are connected; second controlled voltage source H 2 The positive voltage terminal of (2) is connected with an equivalent resistance R in sequence eq Equivalent inductance L eq After being connected in series, the capacitor is connected with a supporting capacitor C 1 The positive electrode of (1) is connected; second controlled voltage source H 2 Negative voltage terminal and supporting capacitor C 1 The negative electrode of (1) is connected; a second controlled current source S 2 Positive and negative output terminals of the capacitor and an output side capacitor C 2 The positive electrode and the negative electrode are connected.
Specifically, calculating the output side capacitance C of N double-active-bridge converters in the single-phase power electronic transformer 2 ' the sum of the capacities as the output side capacitance C 2 According to the parameters in this embodiment, C can be obtained 2 ＝24mF。
Specifically, the equivalent resistance R may be calculated according to formula (4) eq The value of (c):
wherein R is loss The resistance values of the primary and secondary side coils at the high-voltage side are converted for a high-frequency transformer in a single double-active-bridge converter in a single-phase power electronic transformer. R can be obtained according to the parameters in the embodiment eq ＝80mΩ。
Specifically, the equivalence can be calculated according to equation (5)Inductor L eq The value of (c):
wherein L is res And measuring the inductance value obtained at the primary winding of the high-frequency transformer when the secondary winding of the high-frequency transformer in the single double-active-bridge converter in the single-phase power electronic transformer is short-circuited. According to the parameters in this embodiment, L can be obtained eq ＝157μF。
Specifically, the output terminal a of the dual active bridge converter module may be calculated according to equation (6) 2 、b 2 Output voltage control signal:
U ab2 ＝kU dc (6)
wherein k is the primary and secondary side voltage transformation ratio of the high-frequency transformer in the single double-active bridge converter of the single-phase power electronic transformer, and U is the voltage transformation ratio of the primary and secondary sides of the high-frequency transformer dc For the acquired output side capacitance C in the simulation model 2 A direct current voltage signal across the terminals.
Specifically, the output terminal c of the dual active bridge converter module can be calculated according to equation (7) 2 、d 2 Output current control signal:
I cd2 ＝kNI cur (7)
wherein k is the primary and secondary side voltage transformation ratio of the high-frequency transformer in a single double-active-bridge converter in the single-phase power electronic transformer, N is the number of cascaded power modules of the single-phase power electronic transformer, and I cur For the acquired equivalent resistance R flowing through the simulation model eq The current signal of (2).
The voltage-current double closed-loop control model of the embodiment is a simulation circuit built according to an actual circuit as shown in fig. 2, and the number and the connection relationship of elements in the simulation circuit are the same as those in fig. 2.
FIG. 5 is a graph showing the AC side voltage u simulated by the current 1-to-1 simulation model when the load is suddenly increased by 500kW/1.125 Ω at 0.3s from the no-load state sa AC side current i g And a support capacitor C 1 Voltage ofU C1 And an output side DC voltage U dc The waveform of (2). FIG. 6 is a graph showing the AC side voltage u simulated by the large-signal simulation model of the single-phase power electronic transformer in the embodiment when the load is suddenly increased by 500kW/1.125 Ω at 0.3s sa Ac side current i g And a support capacitor C 1 Voltage U on C1 And an output side DC voltage U dc The waveform of (2).
As can be seen from fig. 5 and 6, the simulation result of the large-signal model of the single-phase power electronic transformer in the embodiment is the same as the simulation result of the conventional single-phase power electronic transformer when a load is suddenly applied, and the simulation step lengths of the two simulation steps are both 1 μ s, but under the condition that the simulation time is 0.4s, the simulation time required by the conventional single-phase power electronic transformer is 120s, while the simulation time required by the large-signal simulation model provided by the present invention is 50s. Therefore, compared with the existing single-phase power electronic transformer computer simulation model, the single-phase power electronic transformer model provided by the invention can quickly simulate the port circuit characteristics of a system when the system is disturbed by a large signal.
Those skilled in the art will appreciate that the same technical effects can still be achieved by appropriate decomposition or combination of the modules, models disclosed herein, but such implementation should not be considered as beyond the scope of the present invention.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.
Claims (9)
1. A large signal simulation model of a single-phase power electronic transformer comprises N power modules, wherein each power module consists of an H-bridge converter and a double-active-bridge converter; of N H-bridge convertersThe input sides of the H-bridge converters are cascaded, and the output side of each H-bridge converter is connected with a supporting capacitor C in parallel 1 '; each double-active-bridge converter comprises a resonant circuit consisting of a capacitor and a high-frequency transformer, and the resonant circuit is controlled by adopting square wave voltage with the open-loop duty ratio of 50%; the output side of each double-active-bridge converter is connected with an output side capacitor C in parallel 2 '; the output sides of the N double-active-bridge converters are connected in parallel;
wherein the simulation model comprises: the cascade H-bridge converter equivalent large signal model and the double-active-bridge converter equivalent large signal model connected with the cascade H-bridge converter equivalent large signal model are connected with the cascade H-bridge converter equivalent large signal model;
the cascade H-bridge converter equivalent large signal model is used for simulating N H-bridge converters in the single-phase power electronic transformer;
the double-active-bridge converter equivalent large-signal model is used for simulating N double-active-bridge converters in the single-phase power electronic transformer;
the single-phase power electronic transformer further comprises: a voltage current double closed loop control system;
accordingly, the simulation model further comprises: a voltage and current double closed-loop control model;
the voltage and current double closed-loop control model is used for simulating the voltage and current double closed-loop control system;
the cascade H-bridge converter equivalent large signal model comprises the following components: cascaded H-bridge converter module and first controlled voltage source H 1 A first controlled current source S 1 And a support capacitor C 1 ；
Wherein the content of the first and second substances,
the cascaded H-bridge converter module comprises: 4 input signals u g 、i g 、U C1 N, and 4 output terminals a 1 、b 1 、c 1 、d 1 ；
u g For the collected AC voltage reference signal, i, output by the voltage-current double closed-loop control model g For the collected network side current signal in the simulation model, U C1 For the collected supporting capacitor C 1 N is the single-phase power electronic transformer stageThe number of connected power modules;
a 1 、b 1 are respectively connected with the first controlled voltage source H 1 The positive and negative control terminals of the anode and cathode are connected; c. C 1 、d 1 Respectively connected with the first controlled current source S 1 The positive and negative control terminals of the anode and cathode are connected;
the first controlled voltage source H 1 The two voltage terminals of the transformer are connected with a power grid; the first controlled current source S 1 Positive and negative output terminals of the capacitor and the supporting capacitor C 1 The positive electrode and the negative electrode are connected;
the equivalent large signal model of the double-active-bridge converter comprises:
double-active-bridge converter module and equivalent resistor R eq Equivalent inductance L eq And an output side capacitor C 2 A second controlled voltage source H 2 And a second controlled current source S 2 ；
Wherein the content of the first and second substances,
the dual active bridge converter module comprises 4 input signals I cur 、U dc K, N, and 4 output terminals a 2 、b 2 、c 2 、d 2 ；
U dc For the collected output side capacitance C 2 Direct voltage signals at both ends, I cur For the collected current to flow through the equivalent resistance R eq K is the primary and secondary side voltage transformation ratio of a high-frequency transformer in a single double-active bridge converter of the single-phase power electronic transformer, and N is the number of cascaded power modules of the single-phase power electronic transformer;
a 2 、b 2 respectively connected with the second controlled voltage source H 2 The positive and negative control terminals of (2) are connected; c. C 2 、d 2 Respectively with the second controlled current source S 2 The positive and negative control terminals of the anode and cathode are connected;
the second controlled voltage source H 2 The positive voltage terminal of (2) is connected with the equivalent resistor R in sequence eq The equivalent inductor L eq After being connected in series with the supporting capacitor C 1 The positive electrode of (1) is connected; the second controlled voltage source H 2 Voltage of the negative electrodeTerminal and the support capacitor C 1 The negative electrode of (1) is connected; the second controlled current source S 2 Positive and negative output terminals of the capacitor and the output side capacitor C 2 The positive electrode and the negative electrode are connected.
2. The simulation model of claim 1, wherein the support capacitance C 1 The values of (A) are:
C 1 ＝C 1 ′
wherein, C 1 ' supporting capacitors connected in parallel with the output sides of the single H-bridge converters in the single-phase power electronic transformer.
3. The simulation model of claim 2, wherein the output terminal a of the cascaded H-bridge converter module 1 、b 1 The output voltage control signal is:
u ab1 ＝u g
wherein u is g And the reference signal is an alternating voltage reference signal output by the double closed-loop control model.
4. The simulation model of claim 3, wherein the output terminal c of the cascaded H-bridge converter module 1 、d 1 The output current control signal is:
wherein u is g An AC voltage reference signal, i, output by the double closed-loop control model g For the collected network side current signals in the simulation model, N is the number of the single-phase power electronic transformer cascade power modules, U C1 For the support capacitance C in the collected simulation model 1 The voltage signal of (2).
5. The simulation model of claim 4, wherein the output side capacitance C 2 The value of is N double-active-bridge converter output side capacitors C in the single-phase power electronic transformer 2 ' of the total volume.
6. The simulation model of claim 5, wherein the equivalent resistance R eq The values of (A) are:
wherein R is loss And converting the resistance values of the primary and secondary coils at the high-voltage side for the high-frequency transformer in a single double-active-bridge converter in the single-phase power electronic transformer.
7. The simulation model of claim 6, wherein the equivalent inductance L eq The values of (A) are:
wherein L is res And measuring the inductance value obtained at the primary winding of the high-frequency transformer when the secondary winding of the high-frequency transformer in the single double-active-bridge converter in the single-phase power electronic transformer is short-circuited.
8. The simulation model of claim 7, wherein the output terminal a of the dual active bridge converter module 2 、b 2 The output voltage control signal is:
U ab2 ＝kU dc
k is the primary and secondary side voltage transformation ratio of the high-frequency transformer in the single double-active bridge converter of the single-phase power electronic transformer, and U dc For the output side capacitance C in the collected simulation model 2 A direct current voltage signal across.
9. According to the claimThe simulation model of claim 8, wherein the output terminal c of the dual active bridge converter module 2 、d 2 The output current control signal is:
I cd2 ＝kNI cur
k is the primary and secondary side voltage transformation ratio of a high-frequency transformer in a single double-active-bridge converter in the single-phase power electronic transformer, N is the number of the cascaded power modules of the single-phase power electronic transformer, and I cur For the acquired equivalent resistance R flowing through the simulation model eq The current signal of (a).
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| CN110071649B (en) * | 2019-05-30 | 2020-07-31 | 中国科学院电工研究所 | Electromagnetic transient simulation system for power module of cascaded H-bridge type power electronic transformer |
| CN110518801B (en) * | 2019-07-11 | 2020-12-08 | 杭州电子科技大学 | Small signal modeling method for double-active full-bridge converter under double phase-shift modulation |
| CN110968973B (en) * | 2019-11-11 | 2023-06-16 | 上海科梁信息科技股份有限公司 | Simulation method, control method, electronic equipment and storage medium of transformer model |
| CN111079364B (en) * | 2019-11-25 | 2023-07-14 | 上海科梁信息科技股份有限公司 | Simulation method and simulation platform of direct-current transformer and readable storage medium |
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