CN116937625B - Transition transformation structure of flexible traction substation and control method thereof - Google Patents
Transition transformation structure of flexible traction substation and control method thereof 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
- H02J3/26—Arrangements for eliminating or reducing asymmetry in polyphase networks
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60M—POWER SUPPLY LINES, AND DEVICES ALONG RAILS, FOR ELECTRICALLY- PROPELLED VEHICLES
- B60M3/00—Feeding power to supply lines in contact with collector on vehicles; Arrangements for consuming regenerative power
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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
- H02J3/241—The oscillation concerning frequency
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
- H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
- H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
- H02M5/453—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
- H02M5/458—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M5/4585—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only having a rectifier with controlled elements
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Abstract
The invention discloses a transition transformation structure of a flexible traction substation and a control method thereof, wherein the transition transformation structure comprises a first traction substation, a second traction substation, a third traction substation, a contact net, a steel rail, a first electric phase separation, a second electric phase separation and a third electric phase separation; the first traction substation is connected with the contact net and the steel rail; the third traction substation is connected with the other end of the second electric phase splitting, the third electric phase splitting, the contact net and the steel rail. The invention improves the power supply capacity and reliability of the transformation substation, maintains the advantage of strong impact resistance of the traditional traction power supply side, and reduces the engineering cost and maintenance cost of the traction substation. The three-phase power grid side current unbalance management when the original beta power supply arm is used for supplying power is realized, the output voltage fluctuation suppression of the single-phase inverter circuit is realized, the good electric energy quality of the three-phase power grid side in the transformation process of the flexible traction power supply system is ensured, and the impact resistance of the traction power grid side is improved.
Description
Technical Field
The invention relates to the technical field of flexible traction power supply systems; the transition transformation structure of the flexible traction substation and the control method thereof are particularly included.
Background
At present, three-phase-two-phase power supply modes are adopted in electrified railway traction power supply systems in China. The traction substation mainly adopts a Vv traction transformer to take electricity from a three-phase power grid, and the secondary side of the Vv traction transformer is divided into alpha and beta power supply arms to supply power for the traction grid after the voltage is reduced. Because the amplitude, the phase and the frequency of the output voltages of the two power supply arms and the two traction substation are difficult to be consistent, the two power supply arms and the two traction substation need to be provided with an electric split phase, and the running speed of the train is greatly restricted. Meanwhile, the existing traction power supply system has the problems of poor power quality, insufficient power supply capacity, low capacity utilization rate and the like.
The flexible traction power supply system adopts a flexible traction transformer to realize full-line through power supply, so that the railway transportation capacity is greatly improved, and meanwhile, the problem of electric energy quality is solved. In the process of modifying the traditional traction power supply system to the flexible traction power supply system, the traditional power substation in the line is required to be modified in stages, and the traditional traction power substation and the flexible traction power substation exist in the line at the same time, so that the power supply capacity of the traction power supply system and the power quality of a power grid side are ensured, and the transition modification structure and the control method of the flexible traction power substation are required to be researched.
Disclosure of Invention
Aiming at the defects in the prior art, the transition transformation structure of the flexible traction substation and the control method thereof provided by the invention solve the problems that the existing traction power supply system has poor electric energy quality, insufficient power supply capacity and low capacity utilization rate, and the traditional traction power supply system can not smoothly transition to the flexible traction power supply system.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
the transition transformation structure of the flexible traction substation comprises a first traction substation, a second traction substation, a third traction substation, a contact net, a steel rail, a first electric phase separation, a second electric phase separation and a third electric phase separation; the first traction substation is connected with the contact net and the steel rail; the third traction substation is connected with the other end of the second electric phase separation, the third electric phase separation, the contact net and the steel rail;
The second traction substation comprises a second Vv traction transformer, a breaker QF1', a breaker QF2', a breaker QF3', a breaker QF4, a second flexible traction transformer and a first power supply arm beta; the primary side three phases of the second traditional Vv traction transformer are connected with a three-phase power grid; the secondary side of the second traditional Vv traction transformer is connected with one end of a breaker QF 1'; the secondary side of the second traditional Vv traction transformer is connected with one end of the breaker QF2' and one end of the first power supply arm beta; the secondary side of the second traditional Vv traction transformer is connected with one end of a breaker QF3' and one end of a breaker QF 4; the other end of the breaker QF1', the other end of the breaker QF2' and the other end of the breaker QF3' are respectively connected with the input end of the second flexible traction transformer; the other end of the breaker QF4 is connected with one end of the first electric phase separation and one end of the second electric phase separation; the other end of the first power supply arm beta is connected with a steel rail; the first output end of the second flexible traction transformer is connected with the steel rail; the second output end of the second flexible traction transformer is connected with the other end of the first electric phase separation and the contact net;
the second flexible traction transformer comprises a second matching transformer and a second three-phase-single-phase converter; the other end of the first phase connection breaker QF1' of the primary side of the second matching transformer; the second phase of the primary side of the second matching transformer is connected with the other end of the breaker QF 2'; the third phase of the primary side of the second matching transformer is connected with the other end of the breaker QF 3'; the secondary side of the second matching transformer is connected with the input end of the second three-phase-single-phase converter; the output end of the second three-phase-single-phase converter is used as the output end of the second flexible traction transformer; the primary side of the second matching transformer is used as an input end of the second flexible traction transformer;
The three-phase-single-phase converter comprises an input filter circuit, a three-phase rectifying circuit and a single-phase inverter circuit which are sequentially connected.
The control method for the transition transformation structure of the flexible traction substation comprises the following steps:
s1, acquiring relevant circuit information, and if the circuit to be controlled is a three-phase rectifying circuit, entering a step S2; if the circuit to be controlled is a single-phase inverter circuit, the step S6 is performed;
S2, establishing a three-phase rectification circuit mathematical model according to the acquired related circuit information;
s3, calculating according to a three-phase rectification circuit mathematical model to obtain a three-phase rectification circuit fundamental frequency modulation wave;
S4, acquiring and obtaining a three-phase power grid side negative sequence modulation wave according to the acquired related circuit information and the three-phase power grid side negative sequence current component;
s5, obtaining a three-phase rectification circuit modulation wave through a three-phase power grid side negative sequence modulation wave and a three-phase rectification circuit fundamental frequency modulation wave, and completing three-phase rectification circuit control;
s6, obtaining output voltage of the single-phase inverter circuit according to the obtained related circuit information, and establishing a mathematical model of the single-phase inverter circuit;
s7, obtaining a fundamental frequency modulation wave of the single-phase inverter circuit according to a single-phase inverter circuit mathematical model;
S8, obtaining an output voltage fluctuation component according to the output voltage of the single-phase inverter circuit;
S9, obtaining the modulation wave of the single-phase inverter circuit according to the fundamental frequency modulation wave and the output voltage fluctuation component of the single-phase inverter circuit, and completing the control of the single-phase inverter circuit.
The beneficial effects of the invention are as follows:
1. The invention provides a transition transformation structure of a flexible traction substation, which is characterized in that a transformation substation is transformed in a semi-flexible way at the joint of a flexible traction power supply system through section and an existing traction power supply system, a flexible traction transformer is adopted to supply power to a contact network on the flexible traction power supply side of the transformation substation, electric phase separation between the transformation substation and a front flexible traction power substation is canceled, the flexible traction power supply side is ensured to supply power in a through way, meanwhile, an original beta power supply arm of the transformation substation is reserved to supply power to a contact network on the traditional traction power supply side, the power supply capacity and reliability of the transformation substation are greatly improved, the advantage of strong shock resistance of the traditional traction power supply side is reserved, and the engineering cost and maintenance cost of the traction power substation are reduced.
2. The invention provides a control method for modifying a traction substation in a semi-flexible manner, which can realize basic control of a three-phase rectifying circuit and a single-phase inverter circuit, and simultaneously the three-phase rectifying circuit of the modified substation can realize unbalanced control of current at the three-phase power grid side when the original beta power supply arm supplies power, and the single-phase inverter circuit can realize output voltage fluctuation suppression, so that the power quality of the three-phase power grid side in the modification process of a flexible traction power supply system is good, and meanwhile, the impact resistance of the traction grid side is improved.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic diagram of a three-phase-to-single-phase inverter according to the present invention;
FIG. 3 is a control flow diagram of the present invention;
FIG. 4 is a schematic diagram of an internal control structure of a three-phase rectifying circuit;
fig. 5 is a schematic diagram of an internal control structure of the single-phase inverter circuit.
Detailed Description
The following description of the embodiments of the present invention is provided to facilitate understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and all the inventions which make use of the inventive concept are protected by the spirit and scope of the present invention as defined and defined in the appended claims to those skilled in the art.
As shown in FIG. 1, the transition transformation structure of the flexible traction substation comprises a first traction substation, a second traction substation, a third traction substation, a contact net, a steel rail, a first electric phase separation, a second electric phase separation and a third electric phase separation; the first traction substation is connected with the contact net and the steel rail; the third traction substation is connected with the other end of the second electric phase separation, the third electric phase separation, the contact net and the steel rail;
The second traction substation comprises a second Vv traction transformer, a breaker QF1', a breaker QF2', a breaker QF3', a breaker QF4, a second flexible traction transformer and a first power supply arm beta; the primary side three phases of the second traditional Vv traction transformer are connected with a three-phase power grid; the secondary side of the second traditional Vv traction transformer is connected with one end of a breaker QF 1'; the secondary side of the second traditional Vv traction transformer is connected with one end of the breaker QF2' and one end of the first power supply arm beta; the secondary side of the second traditional Vv traction transformer is connected with one end of a breaker QF3' and one end of a breaker QF 4; the other end of the breaker QF1', the other end of the breaker QF2' and the other end of the breaker QF3' are respectively connected with the input end of the second flexible traction transformer; the other end of the breaker QF4 is connected with one end of the first electric phase separation and one end of the second electric phase separation; the other end of the first power supply arm beta is connected with a steel rail; the first output end of the second flexible traction transformer is connected with the steel rail; the second output end of the second flexible traction transformer is connected with the other end of the first electric phase separation and the contact net;
The second flexible traction transformer comprises a second matching transformer and a second three-phase-single-phase converter; the other end of the first phase connection breaker QF1' of the primary side of the second matching transformer; the second phase of the primary side of the second matching transformer is connected with the other end of the breaker QF 2'; the third phase of the primary side of the second matching transformer is connected with the other end of the breaker QF 3'; the secondary side of the second matching transformer is connected with the input end of the second three-phase-single-phase converter; the output end of the second three-phase-single-phase converter is used as the output end of the second flexible traction transformer; the primary side of the second matching transformer serves as the input of the second flexible traction transformer.
The first traction substation comprises a first Vv traction transformer, a breaker QF1, a breaker QF2, a breaker QF3 and a first flexible traction transformer; the primary side of the first Vv traction transformer is connected with a three-phase power grid in a three-phase manner; one end of a first phase connection breaker QF1 of a secondary side of a first Vv traction transformer; the second phase of the secondary side of the first traditional Vv traction transformer is connected with one end of the circuit breaker QF 2; a third phase of the secondary side of the first conventional Vv traction transformer is connected to one end of the circuit breaker QF 3; the other end of the breaker QF1, the other end of the breaker QF2 and the other end of the breaker QF3 are respectively connected with the input end of the first flexible traction transformer; the first output end of the first flexible traction transformer is connected with the steel rail; the second output end of the first flexible traction transformer is connected with the contact net and one end of the first electrical phase separation, but impedance exists in the contact net between the second output end of the first flexible traction transformer and one end of the first electrical phase separation.
The first flexible traction transformer comprises a first matching transformer and a first three-phase-single-phase converter; the primary side of the first matching transformer is connected with the other end of the breaker QF 1; the primary side of the first matching transformer is connected with the other end of the breaker QF 2; the primary side third phase of the first matching transformer is connected with the other end of the breaker QF 3; the secondary side of the first matching transformer is connected with the input end of the first three-phase-single-phase converter; the output end of the first three-phase-single-phase converter is used as the output end of the first flexible traction transformer; the primary side of the first matching transformer serves as the input of the first flexible traction transformer.
The third traction substation comprises a third Vv traction transformer, a breaker QF5, a breaker QF6, a breaker QF7, a power supply arm alpha and a second power supply arm beta; the primary side of a third traditional Vv traction transformer is connected with a three-phase power grid; one end of a first phase connection breaker QF5 of a secondary side of a third traditional Vv traction transformer; a second phase of the secondary side of the third traditional Vv traction transformer is connected with one end of the circuit breaker QF 6; a third phase of the secondary side of the third conventional Vv traction transformer is connected to one end of the circuit breaker QF 7; the other end of the breaker QF5 is connected with one end of the power supply arm alpha; the other end of the power supply arm alpha is connected with the other end of the second electric phase separation and one end of the third electric phase separation; the other end of the breaker QF6 is connected with a steel rail; the other end of the breaker QF7 is connected with one end of a second power supply arm beta; the other end of the second power supply arm beta is connected with the other end of the third electric split phase and the contact net.
As shown in fig. 2, the three-phase-single-phase converter includes an input filter circuit, a three-phase rectifier circuit, a polar capacitor C d1, a polar capacitor C d2, a single-phase inverter circuit, an inductor L n, and a capacitor C n;
The input filter circuit comprises an inductor L 1, an inductor L 2 and an inductor L 3; one end of the inductor L 1 is connected with a first phase matched with the secondary side of the transformer; one end of the inductor L 2 is connected with a second phase matched with the secondary side of the transformer; one end of the inductor L 3 is connected with a third phase matched with the secondary side of the transformer;
The three-phase rectification circuit comprises an insulated gate bipolar transistor S 11, an insulated gate bipolar transistor S 12, an insulated gate bipolar transistor S 13, an insulated gate bipolar transistor S 14, Insulated gate bipolar transistor S 21, insulated gate bipolar transistor S 22, insulated gate bipolar transistor S 23, insulated gate bipolar transistor S 24, Insulated gate bipolar transistor S 31, insulated gate bipolar transistor S 32, insulated gate bipolar transistor S 33, insulated gate bipolar transistor S 34, Diode D 1, diode D 2, diode D 3, diode D 4, diode D 5, and diode D 6; The other end of the inductor L 1 is connected with the emitter of the insulated gate bipolar transistor S 12 and the collector of the insulated gate bipolar transistor S 13; the other end of the inductor L 2 is connected with the emitter of the insulated gate bipolar transistor S 22 and the collector of the insulated gate bipolar transistor S 23; the other end of the inductor L 3 is connected with the emitter of the insulated gate bipolar transistor S 32 and the collector of the insulated gate bipolar transistor S 33; the emitter of the insulated gate bipolar transistor S 13 is connected to the collector of the insulated gate bipolar transistor S 14 and the anode of the diode D 2; The cathode of the diode D 2 is connected with the anode of the diode D 1, the anode of the diode D 3 and the anode of the diode D 5, The cathode of the diode D 4, the cathode of the diode D 6, the cathode of the polar capacitor C d1, the anode of the polar capacitor C d2 and the third input end of the single-phase inverter circuit; the negative electrode of the diode D 1 is connected with the collector of the insulated gate bipolar transistor S 12 and the emitter of the insulated gate bipolar transistor S 11; the emitter of the insulated gate bipolar transistor S 23 is connected to the collector of the insulated gate bipolar transistor S 24 and the anode of the diode D 4; The negative electrode of the diode D 3 is connected with the collector of the insulated gate bipolar transistor S 22 and the emitter of the insulated gate bipolar transistor S 21; the emitter of the insulated gate bipolar transistor S 33 is connected to the collector of the insulated gate bipolar transistor S 34 and the anode of the diode D 6; The negative electrode of the diode D 5 is connected with the collector of the insulated gate bipolar transistor S 32 and the emitter of the insulated gate bipolar transistor S 31; The collector of the insulated gate bipolar transistor S 11 is connected with the collector of the insulated gate bipolar transistor S 21, the collector of the insulated gate bipolar transistor S 31, the anode with the polarity capacitor C d1 and the first input end of the single-phase inverter circuit; An emitter of the insulated gate bipolar transistor S 14 is connected with an emitter of the insulated gate bipolar transistor S 24, an emitter of the insulated gate bipolar transistor S 34 is provided with a negative electrode of the polar capacitor C d2 and a second input end of the single-phase inverter circuit;
The single-phase inverter circuit comprises an insulated gate bipolar transistor S 41, an insulated gate bipolar transistor S 42, an insulated gate bipolar transistor S 43, an insulated gate bipolar transistor S 44, Insulated gate bipolar transistor S 51, insulated gate bipolar transistor S 52, insulated gate bipolar transistor S 53, insulated gate bipolar transistor S 54, Diode D 7, diode D 8, diode D 9, and diode D 10; The collector of the insulated gate bipolar transistor S 41 is connected with the collector of the insulated gate bipolar transistor S 51 and is used as a first input end of the single-phase inverter circuit; the emitter of the insulated gate bipolar transistor S 41 is connected to the collector of the insulated gate bipolar transistor S 42 and the cathode of the diode D 7; An emitter of the insulated gate bipolar transistor S 42 is connected to a collector of the insulated gate bipolar transistor S 43 and one end of the capacitor C n; the emitter of the insulated gate bipolar transistor S 43 is connected to the collector of the insulated gate bipolar transistor S 44 and the anode of the diode D 8; The cathode of diode D 8 is connected to the anode of diode D 7, the cathode of diode D 10 and the anode of diode D 9, And is used as a third input end of the single-phase inverter circuit; The emitter of the insulated gate bipolar transistor S 44 is connected with the emitter of the insulated gate bipolar transistor S 54 and is used as a second input end of the single-phase inverter circuit; the collector of the insulated gate bipolar transistor S 54 is connected to the emitter of the insulated gate bipolar transistor S 53 and the anode of the diode D 10; The emitter of the insulated gate bipolar transistor S 51 is connected to the collector of the insulated gate bipolar transistor S 52 and the cathode of the diode D 9; the emitter of the insulated gate bipolar transistor S 52 is connected to the collector of the edge gate bipolar transistor S 53 and one end of the inductor L n;
The other end of the inductor L n is connected with the other end of the capacitor C n and is used as a second output end of the three-phase-single-phase converter; one end of the capacitor C n is used as a first output end of the three-phase-single-phase converter.
As shown in fig. 3, a control method for a transition transformation structure of a flexible traction substation comprises the following steps:
s1, acquiring relevant circuit information, and if the circuit to be controlled is a three-phase rectifying circuit, entering a step S2; if the circuit to be controlled is a single-phase inverter circuit, the step S6 is performed;
S2, establishing a three-phase rectification circuit mathematical model according to the acquired related circuit information;
s3, calculating according to a three-phase rectification circuit mathematical model to obtain a three-phase rectification circuit fundamental frequency modulation wave;
S4, acquiring and obtaining a three-phase power grid side negative sequence modulation wave according to the acquired related circuit information and the three-phase power grid side negative sequence current component;
s5, obtaining a three-phase rectification circuit modulation wave through a three-phase power grid side negative sequence modulation wave and a three-phase rectification circuit fundamental frequency modulation wave, and completing three-phase rectification circuit control;
s6, obtaining output voltage of the single-phase inverter circuit according to the obtained related circuit information, and establishing a mathematical model of the single-phase inverter circuit;
s7, obtaining a fundamental frequency modulation wave of the single-phase inverter circuit according to a single-phase inverter circuit mathematical model;
S8, obtaining an output voltage fluctuation component according to the output voltage of the single-phase inverter circuit;
S9, obtaining the modulation wave of the single-phase inverter circuit according to the fundamental frequency modulation wave and the output voltage fluctuation component of the single-phase inverter circuit, and completing the control of the single-phase inverter circuit.
As shown in fig. 4, the specific implementation manner of step S2 is as follows: according to the formula:
Obtaining a three-phase rectification circuit mathematical model of the three-phase rectification circuit under a d-q coordinate system; wherein L s is the input filter inductance value of the three-phase rectifying circuit; r s is the input side resistor of the three-phase rectifying circuit; i sd is the component of the input current at the front end of the three-phase rectifying circuit in the d axis; i sq is the component of the input current at the front end of the three-phase rectifying circuit on the q axis; u sd is the component of the input voltage at the front end of the three-phase rectifying circuit in the d axis; u sq is the component of the input voltage at the front end of the three-phase rectifying circuit on the q axis; u zd is the component of the input port voltage of the three-phase rectifying circuit bridge on the d axis; u zq is the component of the input port voltage of the three-phase rectifying circuit bridge on the q axis; ω is angular velocity.
The specific implementation manner of the step S3 is as follows:
S3-1, respectively performing feedforward decoupling treatment on d-axis and q-axis current loops of a three-phase rectification circuit mathematical model under a d-q coordinate system to obtain a mathematical model controlled by the following fundamental frequency voltage:
wherein K ip1 is the proportionality coefficient of the PI controller in the current loop of the three-phase rectifying circuit; k il1 is the integral coefficient of the PI controller in the current loop of the three-phase rectifying circuit; i * sd、i* sq is the reference value of active current and reactive current respectively; s denotes the laplace transform and, Representing an integration operation;
S3-2, converting U zd、Uzq under a d-q coordinate system into a three-phase static abc coordinate system based on a mathematical model of fundamental frequency voltage control to obtain fundamental frequency voltage of an input port of a three-phase rectifying circuit under the three-phase static abc coordinate system;
S3-3, obtaining fundamental frequency modulation waves of the three-phase rectification circuit according to fundamental frequency voltage of the input port of the three-phase rectification circuit under the three-phase static abc coordinate system.
The specific implementation manner of the step S4 is as follows:
s4-1, according to the formula:
Obtaining a three-phase network side current decomposition result of the second flexible traction substation; wherein i sa is the current of phase A input to the front end of the three-phase rectifying circuit, i sb is the current of phase B input to the front end of the three-phase rectifying circuit, and i sc is the current of phase C input to the front end of the three-phase rectifying circuit; i 1 is the amplitude of the fundamental frequency positive sequence current of the three-phase network side current of the second flexible traction substation, I 1 - is the amplitude of the fundamental frequency negative sequence current of the three-phase network side current of the second flexible traction substation, The initial phase of the fundamental frequency positive sequence current of the three-phase network side current of the second flexible traction substation,For the initial phase of the fundamental frequency negative sequence current of the three-phase network side current of the second flexible traction substation, I n is the amplitude of the n-order harmonic positive sequence current of the three-phase network side current of the second flexible traction substation, I n - is the amplitude of the n-order harmonic negative sequence current of the three-phase network side current of the second flexible traction substation,The initial phase of the n-order harmonic positive sequence current of the three-phase network side current of the second flexible traction substation,The initial phase of the n-order harmonic negative sequence current of the three-phase network side current of the second flexible traction substation; pi is an angle of radian; t is time;
s4-2, according to the formula:
Obtaining a transformation result of carrying out negative sequence d-q transformation on the current decomposition result of the three-phase network side of the second flexible traction substation Wherein,Is a negative sequence d-q transformation matrix; i sd is the component of the input current at the front end of the three-phase rectifying circuit in the d axis; i sq is the component of the input current at the front end of the three-phase rectifying circuit on the q axis;
s4-3, transforming the result Obtaining fundamental frequency negative sequence components i sdN and i sqN through a low-pass filter, namely obtaining a three-phase power grid side negative sequence current component; wherein i sdN is the component of the negative sequence current at the d axis input at the front end of the three-phase rectifying circuit; i sqN is the component of the negative sequence current input at the front end of the three-phase rectifying circuit on the q axis;
s4-4, according to the formula:
Obtaining a negative sequence voltage control instruction; wherein U zdN is the component of the negative sequence voltage of the input port of the three-phase rectifying circuit on the d axis; u zqN is the component of the negative sequence voltage of the input port of the three-phase rectifying circuit on the q axis; i * sdN、i* sqN is the reference value of the active and reactive currents of the negative sequence current component respectively;
S4-5, converting a negative sequence voltage control instruction under a d-q coordinate system into a three-phase static abc coordinate system to obtain a negative sequence voltage of an input port of the three-phase rectifying circuit under the three-phase static abc coordinate system;
S4-6, obtaining a three-phase grid side negative sequence modulation wave according to the negative sequence voltage of the input port of the three-phase rectifying circuit under the three-phase static abc coordinate system.
As shown in fig. 5, the mathematical model of the single-phase inverter circuit in step S6 is as follows:
Wherein i Ld and i Lq are the component of the d axis and the component of the q axis of the inductor current in the d-q coordinate system respectively; u od and u oq are the component of the d axis and the component of the q axis of the output voltage of the single-phase inverter circuit in the d-q coordinate system respectively; i od and i oq are the component of the d axis and the component of the q axis of the output current of the single-phase inverter circuit under the d-q coordinate system respectively; c n is a capacitor, S d is a Laplace transform on d-axis component, and U dc is direct-current side voltage; l n is inductance, and S q is Laplace transform of q-axis component.
The specific implementation manner of the step S7 is as follows:
S7-1, according to the formula:
Obtaining an active current reference value of the single-phase inverter circuit And reactive current reference value of single-phase inverter circuitWherein, K np1 and K ni1 are respectively the proportional coefficient and the integral coefficient of the single-phase inverter circuit voltage outer loop PI controller; u * od and u * oq are reference values of active voltage and reactive voltage, respectively;
S7-2, according to the formula:
Obtaining an output voltage control instruction of the single-phase inverter circuit; wherein i * Ld and i * Lq are reference values of active current and reactive current respectively;
S7-3, obtaining an active component and a reactive component of a fundamental frequency modulation wave of the single-phase inverter circuit according to the output voltage of the single-phase inverter circuit under a d-q coordinate system under an output voltage control instruction of the single-phase inverter circuit;
S7-4, according to the formula:
umdq＝uodcos(ωt)+uoqsin(ωt)
And obtaining the fundamental frequency modulation wave of the single-phase inverter circuit.
The specific implementation manner of the step S8 is as follows:
S8-1, converting the output voltage u o of the single-phase inverter circuit from a three-phase static abc coordinate system to a d-q coordinate system to obtain an active component u od and a reactive component u oq of the output voltage of the inverter under the d-q coordinate system;
S8-2, converting the active component u od and the reactive component u oq of the output voltage of the inverter under the d-q coordinate system into a three-phase static abc coordinate system through a low-pass filter to obtain the output voltage u oh of the single-phase inverter circuit after voltage fluctuation is filtered;
S8-3, the output voltage u o of the single-phase inverter circuit and the output voltage u oh of the single-phase inverter circuit after voltage fluctuation is filtered out are subjected to difference, and a voltage fluctuation component u hz of the single-phase inverter circuit is obtained.
The specific implementation manner of the step S9 is as follows: according to the formula:
um＝kpwm·umdq-uhz
Obtaining a modulation wave u m of the single-phase inverter circuit; wherein k pwm is an amplification gain value of the single-phase inverter circuit, and u hz is a voltage fluctuation component of the single-phase inverter circuit; u mqd is the fundamental frequency modulation wave of the single-phase inverter circuit.
In one embodiment of the present invention, discretizing the modulated wave of the single-phase inverter circuit is equivalent to the high frequency:
Wherein u m' (k+1) is a single-phase inverter circuit modulation wave in a k+1 time discrete state, u mqd (k+1) is a fundamental frequency modulation wave of the single-phase inverter circuit in a k+1 time discrete state, and u hz (k+1) is an output voltage fluctuation amount of the single-phase inverter circuit in a k+1 time discrete state;
when the sampling frequency is far greater than the voltage fluctuation frequency of the single-phase inverter circuit, the voltage fluctuation value at the next moment can be equivalent to the voltage fluctuation value at the current moment, and the assumed modulation wave of the single-phase inverter circuit can be equivalent to:
According to the voltage fluctuation amount in the output voltage u o of the single-phase inverter circuit, the voltage fluctuation amount u h separated in the output voltage of the single-phase inverter circuit is opposite to the voltage fluctuation amount u hz generated by the single-phase inverter modulation wave, namely u h＝-uhz, and the modulation wave of the single-phase inverter circuit can be expressed as follows:
Substituting the assumed modulation wave expression of the single-phase inverter circuit into an output voltage expression of the single-phase inverter circuit to obtain the output voltage expression of the single-phase inverter circuit in a discrete state as follows:
According to the expression of the output voltage of the single-phase inverter circuit in the discrete state, the detected voltage fluctuation is injected into the fundamental frequency modulation wave of the single-phase inverter circuit, so that the fluctuation of the output voltage of the single-phase inverter circuit can be effectively restrained.
The invention improves the power supply capacity and reliability of the transformation substation, maintains the advantage of strong impact resistance of the traditional traction power supply side, and reduces the engineering cost and maintenance cost of the traction substation. According to the invention, the unbalanced control of the current at the three-phase power grid side when the original beta power supply arm of the three-phase rectifying circuit of the transformation substation is used for supplying power is realized, the output voltage fluctuation suppression of the single-phase inverter circuit is realized, the good electric energy quality at the three-phase power grid side in the transformation process of the flexible traction power supply system is ensured, and the impact resistance of the traction power grid side is improved.
Claims (12)
1. The control method applied to the transition transformation structure of the flexible traction substation is characterized by comprising the following steps of:
s1, acquiring relevant circuit information, and if the circuit to be controlled is a three-phase rectifying circuit, entering a step S2; if the circuit to be controlled is a single-phase inverter circuit, the step S6 is performed;
S2, establishing a three-phase rectification circuit mathematical model according to the acquired related circuit information;
s3, calculating according to a three-phase rectification circuit mathematical model to obtain a three-phase rectification circuit fundamental frequency modulation wave;
S4, acquiring and obtaining a three-phase power grid side negative sequence modulation wave according to the acquired related circuit information and the three-phase power grid side negative sequence current component;
s5, obtaining a three-phase rectification circuit modulation wave through a three-phase power grid side negative sequence modulation wave and a three-phase rectification circuit fundamental frequency modulation wave, and completing three-phase rectification circuit control;
s6, obtaining output voltage of the single-phase inverter circuit according to the obtained related circuit information, and establishing a mathematical model of the single-phase inverter circuit;
s7, obtaining a fundamental frequency modulation wave of the single-phase inverter circuit according to a single-phase inverter circuit mathematical model;
S8, obtaining an output voltage fluctuation component according to the output voltage of the single-phase inverter circuit;
s9, obtaining a modulation wave of the single-phase inverter circuit according to the fundamental frequency modulation wave and the output voltage fluctuation component of the single-phase inverter circuit, and completing control of the single-phase inverter circuit;
The transition transformation structure of the flexible traction substation comprises a first traction substation, a second traction substation, a third traction substation, a contact net, a steel rail, a first electric phase separation, a second electric phase separation and a third electric phase separation; the first traction substation is connected with the contact net and the steel rail; the third traction substation is connected with the other end of the second electric phase separation, the third electric phase separation, the contact net and the steel rail;
The second traction substation comprises a second Vv traction transformer, a breaker QF1', a breaker QF2', a breaker QF3', a breaker QF4, a second flexible traction transformer and a first power supply arm beta; the primary side three phases of the second traditional Vv traction transformer are connected with a three-phase power grid; the secondary side of the second traditional Vv traction transformer is connected with one end of a breaker QF 1'; the secondary side of the second traditional Vv traction transformer is connected with one end of the breaker QF2' and one end of the first power supply arm beta; the secondary side of the second traditional Vv traction transformer is connected with one end of a breaker QF3' and one end of a breaker QF 4; the other end of the breaker QF1', the other end of the breaker QF2' and the other end of the breaker QF3' are respectively connected with the input end of the second flexible traction transformer; the other end of the breaker QF4 is connected with one end of the first electric phase separation and one end of the second electric phase separation; the other end of the first power supply arm beta is connected with a steel rail; the first output end of the second flexible traction transformer is connected with the steel rail; the second output end of the second flexible traction transformer is connected with the other end of the first electric phase separation and the contact net;
the second flexible traction transformer comprises a second matching transformer and a second three-phase-single-phase converter; the other end of the first phase connection breaker QF1' of the primary side of the second matching transformer; the second phase of the primary side of the second matching transformer is connected with the other end of the breaker QF 2'; the third phase of the primary side of the second matching transformer is connected with the other end of the breaker QF 3'; the secondary side of the second matching transformer is connected with the input end of the second three-phase-single-phase converter; the output end of the second three-phase-single-phase converter is used as the output end of the second flexible traction transformer; the primary side of the second matching transformer is used as an input end of the second flexible traction transformer;
The three-phase-single-phase converter comprises an input filter circuit, a three-phase rectifying circuit and a single-phase inverter circuit which are sequentially connected.
2. The control method of claim 1, wherein the first traction substation comprises a first Vv traction transformer, a breaker QF1, a breaker QF2, a breaker QF3, a first flexible traction transformer; the primary side of the first Vv traction transformer is connected with a three-phase power grid in a three-phase manner; one end of a first phase connection breaker QF1 of a secondary side of a first Vv traction transformer; the second phase of the secondary side of the first traditional Vv traction transformer is connected with one end of the circuit breaker QF 2; a third phase of the secondary side of the first conventional Vv traction transformer is connected to one end of the circuit breaker QF 3; the other end of the breaker QF1, the other end of the breaker QF2 and the other end of the breaker QF3 are respectively connected with the input end of the first flexible traction transformer; the first output end of the first flexible traction transformer is connected with the steel rail; the second output end of the first flexible traction transformer is connected with one end of the contact net and one end of the first electric phase separation.
3. The control method of claim 2, wherein the first flexible traction transformer comprises a first matching transformer and a first three-phase-to-single-phase converter; the primary side of the first matching transformer is connected with the other end of the breaker QF 1; the primary side of the first matching transformer is connected with the other end of the breaker QF 2; the primary side third phase of the first matching transformer is connected with the other end of the breaker QF 3; the secondary side of the first matching transformer is connected with the input end of the first three-phase-single-phase converter; the output end of the first three-phase-single-phase converter is used as the output end of the first flexible traction transformer; the primary side of the first matching transformer serves as the input of the first flexible traction transformer.
4. The control method according to claim 1, wherein the third traction substation comprises a third Vv traction transformer, a breaker QF5, a breaker QF6, a breaker QF7, a supply arm α, a second supply arm β; the primary side of a third traditional Vv traction transformer is connected with a three-phase power grid; one end of a first phase connection breaker QF5 of a secondary side of a third traditional Vv traction transformer; a second phase of the secondary side of the third traditional Vv traction transformer is connected with one end of the circuit breaker QF 6; a third phase of the secondary side of the third conventional Vv traction transformer is connected to one end of the circuit breaker QF 7; the other end of the breaker QF5 is connected with one end of the power supply arm alpha; the other end of the power supply arm alpha is connected with the other end of the second electric phase separation and one end of the third electric phase separation; the other end of the breaker QF6 is connected with a steel rail; the other end of the breaker QF7 is connected with one end of a second power supply arm beta; the other end of the second power supply arm beta is connected with the other end of the third electric split phase and the contact net.
5. A control method according to claim 1 or 3, wherein the three-phase-single-phase converter further comprises a polar capacitor C d1, a polar capacitor C d2, an inductance L n and a capacitor C n;
The input filter circuit comprises an inductor L 1, an inductor L 2 and an inductor L 3; one end of the inductor L 1 is connected with a first phase matched with the secondary side of the transformer; one end of the inductor L 2 is connected with a second phase matched with the secondary side of the transformer; one end of the inductor L 3 is connected with a third phase matched with the secondary side of the transformer;
The three-phase rectification circuit comprises an insulated gate bipolar transistor S 11, an insulated gate bipolar transistor S 12, an insulated gate bipolar transistor S 13, an insulated gate bipolar transistor S 14, Insulated gate bipolar transistor S 21, insulated gate bipolar transistor S 22, insulated gate bipolar transistor S 23, insulated gate bipolar transistor S 24, Insulated gate bipolar transistor S 31, insulated gate bipolar transistor S 32, insulated gate bipolar transistor S 33, insulated gate bipolar transistor S 34, Diode D 1, diode D 2, diode D 3, diode D 4, diode D 5, and diode D 6; The other end of the inductor L 1 is connected with the emitter of the insulated gate bipolar transistor S 12 and the collector of the insulated gate bipolar transistor S 13; the other end of the inductor L 2 is connected with the emitter of the insulated gate bipolar transistor S 22 and the collector of the insulated gate bipolar transistor S 23; the other end of the inductor L 3 is connected with the emitter of the insulated gate bipolar transistor S 32 and the collector of the insulated gate bipolar transistor S 33; the emitter of the insulated gate bipolar transistor S 13 is connected to the collector of the insulated gate bipolar transistor S 14 and the anode of the diode D 2; The cathode of the diode D 2 is connected with the anode of the diode D 1, the anode of the diode D 3 and the anode of the diode D 5, The cathode of the diode D 4, the cathode of the diode D 6, the cathode of the polar capacitor C d1, the anode of the polar capacitor C d2 and the third input end of the single-phase inverter circuit; the negative electrode of the diode D 1 is connected with the collector of the insulated gate bipolar transistor S 12 and the emitter of the insulated gate bipolar transistor S 11; the emitter of the insulated gate bipolar transistor S 23 is connected to the collector of the insulated gate bipolar transistor S 24 and the anode of the diode D 4; The negative electrode of the diode D 3 is connected with the collector of the insulated gate bipolar transistor S 22 and the emitter of the insulated gate bipolar transistor S 21; the emitter of the insulated gate bipolar transistor S 33 is connected to the collector of the insulated gate bipolar transistor S 34 and the anode of the diode D 6; The negative electrode of the diode D 5 is connected with the collector of the insulated gate bipolar transistor S 32 and the emitter of the insulated gate bipolar transistor S 31; The collector of the insulated gate bipolar transistor S 11 is connected with the collector of the insulated gate bipolar transistor S 21, the collector of the insulated gate bipolar transistor S 31, the anode with the polarity capacitor C d1 and the first input end of the single-phase inverter circuit; An emitter of the insulated gate bipolar transistor S 14 is connected with an emitter of the insulated gate bipolar transistor S 24, an emitter of the insulated gate bipolar transistor S 34 is provided with a negative electrode of the polar capacitor C d2 and a second input end of the single-phase inverter circuit;
The single-phase inverter circuit comprises an insulated gate bipolar transistor S 41, an insulated gate bipolar transistor S 42, an insulated gate bipolar transistor S 43, an insulated gate bipolar transistor S 44, Insulated gate bipolar transistor S 51, insulated gate bipolar transistor S 52, insulated gate bipolar transistor S 53, insulated gate bipolar transistor S 54, Diode D 7, diode D 8, diode D 9, and diode D 10; The collector of the insulated gate bipolar transistor S 41 is connected with the collector of the insulated gate bipolar transistor S 51 and is used as a first input end of the single-phase inverter circuit; the emitter of the insulated gate bipolar transistor S 41 is connected to the collector of the insulated gate bipolar transistor S 42 and the cathode of the diode D 7; An emitter of the insulated gate bipolar transistor S 42 is connected to a collector of the insulated gate bipolar transistor S 43 and one end of the capacitor C n; the emitter of the insulated gate bipolar transistor S 43 is connected to the collector of the insulated gate bipolar transistor S 44 and the anode of the diode D 8; The cathode of diode D 8 is connected to the anode of diode D 7, the cathode of diode D 10 and the anode of diode D 9, And is used as a third input end of the single-phase inverter circuit; The emitter of the insulated gate bipolar transistor S 44 is connected with the emitter of the insulated gate bipolar transistor S 54 and is used as a second input end of the single-phase inverter circuit; the collector of the insulated gate bipolar transistor S 54 is connected to the emitter of the insulated gate bipolar transistor S 53 and the anode of the diode D 10; The emitter of the insulated gate bipolar transistor S 51 is connected to the collector of the insulated gate bipolar transistor S 52 and the cathode of the diode D 9; the emitter of the insulated gate bipolar transistor S 52 is connected to the collector of the edge gate bipolar transistor S 53 and one end of the inductor L n;
The other end of the inductor L n is connected with the other end of the capacitor C n and is used as a second output end of the three-phase-single-phase converter; one end of the capacitor C n is used as a first output end of the three-phase-single-phase converter.
6. The control method according to claim 1, wherein the specific implementation manner of step S2 is as follows:
according to the formula:
Obtaining a three-phase rectification circuit mathematical model of the three-phase rectification circuit under a d-q coordinate system; wherein L s is the input filter inductance value of the three-phase rectifying circuit; r s is the input side resistor of the three-phase rectifying circuit; i sd is the component of the input current at the front end of the three-phase rectifying circuit in the d axis; i sq is the component of the input current at the front end of the three-phase rectifying circuit on the q axis; u sd is the component of the input voltage at the front end of the three-phase rectifying circuit in the d axis; u sq is the component of the input voltage at the front end of the three-phase rectifying circuit on the q axis; u zd is the component of the input port voltage of the three-phase rectifying circuit bridge on the d axis; u zq is the component of the input port voltage of the three-phase rectifying circuit bridge on the q axis; ω is angular velocity.
7. The control method according to claim 6, wherein the step S3 is specifically implemented as follows:
S3-1, respectively performing feedforward decoupling treatment on d-axis and q-axis current loops of a three-phase rectification circuit mathematical model under a d-q coordinate system to obtain a mathematical model controlled by the following fundamental frequency voltage:
wherein K ip1 is the proportionality coefficient of the PI controller in the current loop of the three-phase rectifying circuit; k il1 is the integral coefficient of the PI controller in the current loop of the three-phase rectifying circuit; i * sd、i* sq is the reference value of active current and reactive current respectively; s denotes the laplace transform and, Representing an integration operation;
S3-2, converting U zd、Uzq under a d-q coordinate system into a three-phase static abc coordinate system based on a mathematical model of fundamental frequency voltage control to obtain fundamental frequency voltage of an input port of a three-phase rectifying circuit under the three-phase static abc coordinate system;
S3-3, obtaining fundamental frequency modulation waves of the three-phase rectification circuit according to fundamental frequency voltage of the input port of the three-phase rectification circuit under the three-phase static abc coordinate system.
8. The control method according to claim 7, wherein the step S4 is specifically implemented as follows:
s4-1, according to the formula:
obtaining a three-phase network side current decomposition result of the second flexible traction substation; wherein i sa is the current of phase A input to the front end of the three-phase rectifying circuit, i sb is the current of phase B input to the front end of the three-phase rectifying circuit, and i sc is the current of phase C input to the front end of the three-phase rectifying circuit; i 1 is the amplitude of the fundamental frequency positive sequence current of the three-phase network side current of the second flexible traction substation, I 1 - is the amplitude of the fundamental frequency negative sequence current of the three-phase network side current of the second flexible traction substation, phi 1 is the initial phase of the fundamental frequency positive sequence current of the three-phase network side current of the second flexible traction substation, phi 1 - is the initial phase of the fundamental frequency negative sequence current of the three-phase network side current of the second flexible traction substation, I n is the amplitude of the n-order harmonic positive sequence current of the three-phase network side current of the second flexible traction substation, I n - is the amplitude of the n-order harmonic negative sequence current of the three-phase network side current of the second flexible traction substation, phi n is the initial phase of the n-order harmonic positive sequence current of the three-phase network side current of the second flexible traction substation, phi n - is the initial phase of the n-order harmonic negative sequence current of the three-phase network side current of the second flexible traction substation; pi is an angle of radian; t is time;
s4-2, according to the formula:
Obtaining a transformation result of carrying out negative sequence d-q transformation on the current decomposition result of the three-phase network side of the second flexible traction substation ; Wherein,Is a negative sequence d-q transformation matrix; i sd is the component of the input current at the front end of the three-phase rectifying circuit in the d axis; i sq is the component of the input current at the front end of the three-phase rectifying circuit on the q axis;
s4-3, transforming the result Obtaining fundamental frequency negative sequence components i sdN and i sqN through a low-pass filter, namely obtaining a three-phase power grid side negative sequence current component; wherein i sdN is the component of the negative sequence current at the d axis input at the front end of the three-phase rectifying circuit; i sqN is the component of the negative sequence current input at the front end of the three-phase rectifying circuit on the q axis;
s4-4, according to the formula:
obtaining negative sequence voltages U zdN and U zqN; wherein U zdN is the component of the negative sequence voltage of the input port of the three-phase rectifying circuit on the d axis; u zqN is the component of the negative sequence voltage of the input port of the three-phase rectifying circuit on the q axis; i * sdN、i* sqN is the reference value of the active and reactive currents of the negative sequence current component respectively;
s4-5, converting negative sequence voltages U zdN and U zqN under a d-q coordinate system to a three-phase static abc coordinate system to obtain negative sequence voltages of input ports of the three-phase rectifying circuit under the three-phase static abc coordinate system;
S4-6, obtaining a three-phase grid side negative sequence modulation wave according to the negative sequence voltage of the input port of the three-phase rectifying circuit under the three-phase static abc coordinate system.
9. The control method according to claim 8, characterized in that the single-phase inverter circuit mathematical model in step S6 is as follows:
Wherein i Ld and i Lq are the component of the d axis and the component of the q axis of the inductor current in the d-q coordinate system respectively; u od and u oq are the component of the d axis and the component of the q axis of the output voltage of the single-phase inverter circuit in the d-q coordinate system respectively; i od and i oq are the component of the d axis and the component of the q axis of the output current of the single-phase inverter circuit under the d-q coordinate system respectively; c n is a capacitor, S d is a Laplace transform on d-axis component, and U dc is direct-current side voltage; l n is inductance, and S q is Laplace transform of q-axis component.
10. The control method according to claim 9, wherein the specific implementation manner of step S7 is as follows:
S7-1, according to the formula:
Obtaining an active current reference value of the single-phase inverter circuit And reactive current reference value of single-phase inverter circuit; Wherein, K np1 and K ni1 are respectively the proportional coefficient and the integral coefficient of the single-phase inverter circuit voltage outer loop PI controller; u * od and u * oq are reference values of active voltage and reactive voltage, respectively;
S7-2, according to the formula:
Obtaining an output voltage control instruction of the single-phase inverter circuit; wherein i * Ld and i * Lq are reference values of active current and reactive current respectively;
S7-3, obtaining an active component and a reactive component of a fundamental frequency modulation wave of the single-phase inverter circuit according to the output voltage of the single-phase inverter circuit under a d-q coordinate system under an output voltage control instruction of the single-phase inverter circuit;
S7-4, according to the formula:
And obtaining the fundamental frequency modulation wave of the single-phase inverter circuit.
11. The control method according to claim 10, wherein the specific implementation manner of step S8 is as follows:
S8-1, converting the output voltage u o of the single-phase inverter circuit from a three-phase static abc coordinate system to a d-q coordinate system to obtain an active component u od and a reactive component u oq of the output voltage of the inverter under the d-q coordinate system;
S8-2, converting the active component u od and the reactive component u oq of the output voltage of the inverter under the d-q coordinate system into a three-phase static abc coordinate system through a low-pass filter to obtain the output voltage u oh of the single-phase inverter circuit after voltage fluctuation is filtered;
S8-3, the output voltage u o of the single-phase inverter circuit and the output voltage u oh of the single-phase inverter circuit after voltage fluctuation is filtered out are subjected to difference, and a voltage fluctuation component u hz of the single-phase inverter circuit is obtained.
12. The control method according to claim 11, wherein the specific implementation manner of step S9 is as follows:
according to the formula:
Obtaining the modulation wave of the single-phase inverter circuit ; Wherein k pwm is an amplification gain value of the single-phase inverter circuit, and u hz is a voltage fluctuation component of the single-phase inverter circuit; u mqd is the fundamental frequency modulation wave of the single-phase inverter circuit.
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