CN116073391A - Phase sequence self-adaptive grid-connected control method and system of chained SVG device - Google Patents
Phase sequence self-adaptive grid-connected control method and system of chained SVG device 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
- H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
- H02J3/1821—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators
- H02J3/1835—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control
- H02J3/1842—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control wherein at least one reactive element is actively controlled by a bridge converter, e.g. active filters
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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
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Abstract
The invention discloses a phase sequence self-adaptive grid-connected control method and a system of a chained SVG device, wherein the method comprises the following steps: 1) Acquiring three-phase line voltage input by SVG, and obtaining a three-phase line voltage synchronous signal; 2) The method comprises the steps of inputting three-phase voltages as a software phase-locked loop, judging voltage phase sequences by using d-axis components and q-axis components of the voltages output by the software phase-locked loop, and adjusting any two-phase voltages to positive sequences if the voltage phase sequences are negative sequences; 3) Acquiring data of SVG three-phase current and three-phase synchronous voltage during SVG high-voltage switching-on; 4) According to the data of the SVG three-phase current and the three-phase synchronous voltage during high-voltage brake charging, a corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage is obtained; 5) And performing line sequence adjustment on the three-phase current acquisition signals output by the SVG, calculating three-phase modulation waves, and distributing the three-phase modulation waves to a three-phase converter chain. The invention has the advantages of automatically correcting the synchronous voltage phase sequence, improving the debugging efficiency and the like.
Description
Technical Field
The invention mainly relates to the technical field of electric energy management, in particular to a phase sequence self-adaptive grid-connected control method and system of a chained SVG device.
Background
In recent years, as a high-voltage dynamic reactive power compensation device, the three-phase chained SVG is increasingly widely applied to a power grid. The three-phase chained SVG is a grid-connected operation device, and in order to realize control, information of input voltage of the device needs to be obtained in real time. In engineering, the chain type SVG device often collects the voltage transformer signal of the high-voltage bus as the self voltage synchronization signal, and does not directly detect the input voltage of the inlet wire end of the device. As grid-connected operation equipment, the normal operation of the chained SVG depends on the correct correspondence of the three-phase input voltage and the three-phase synchronous voltage of the device, and the required voltage phase sequence is positive, and the on-site constructor is required to carry out secondary wiring strictly according to the ABC three-phase sequence relation. However, in the installation site of the SVG equipment, due to various reasons such as missing or wrong marking of the cable phase sequence, wrong wiring of constructors, reverse direction of the PT secondary side cables of the bus, and the like, abnormal connection of secondary cables inevitably exists, so that input voltage and synchronous voltage cannot be correctly corresponding to each other in three phases, and further the SVG is started to be over-current, and equipment operation and equipment safety are affected. Therefore, before the SVG is put into operation, a manufacturer is required to debug a person to carefully check a secondary wiring of the device on site, and use special equipment to check related voltage and current waveforms to perform phase matching, if phase sequence errors are judged, the cable wiring is required to be manually adjusted, the process is time-consuming and tedious, and higher requirements are also put into the capability of the debugging person. Therefore, the grid-connected control method applied to the chained SVG and capable of automatically adapting to abnormal phase sequence of power grid voltage is developed, and has good application value.
In order to realize the identification and correction of abnormal phase sequence of grid voltage by grid-connected equipment such as SVG and the like, and further self-adaptive grid-connected operation, a plurality of beneficial exploration are carried out in the industry, and the patent and literature strongly related to the invention are as follows:
the invention patent application (application number CN201410280773. X) discloses a line sequence active detection and self-adaption system and an implementation method, the method firstly obtains synchronous voltage phase information in a voltage zero-crossing phase locking mode, and obtains d-axis and q-axis components of voltage by utilizing rotation coordinate transformation, so as to judge voltage phase sequence, then controls a three-phase controlled bridge to output a short-circuit pulse short-circuit power grid at a positive zero crossing point of the voltage according to a phase sequence relation to obtain short-circuit current, judges the line sequence relation between a synchronous signal and a main circuit cable according to the response of the short-circuit current, finally automatically adjusts the phase of the synchronous voltage according to the phase sequence and the line sequence relation, and the control device is used for normal grid-connected operation.
From the above analysis, in order to realize phase sequence self-adaptive grid-connected operation of devices such as SVG, the technical scheme adopted at present has certain limitations, and is mainly reflected in:
(1) The application range is limited, such as being only applicable to low-voltage SVG devices adopting a three-phase bridge topology or SVG devices provided with incoming line input voltage detection equipment, and the like;
(2) The function is limited, if the device is only used for detecting whether the phase sequence is abnormal or not, and when the phase sequence is abnormal, the error sequence correction of the grid-connected control strategy of the device cannot be realized.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: aiming at the problems existing in the prior art, the invention provides a phase sequence self-adaptive grid-connected control method and a phase sequence self-adaptive grid-connected control system for a chained SVG device, which can automatically correct the corresponding relation between synchronous voltage phase sequences and secondary cables and improve the debugging efficiency.
In order to solve the technical problems, the technical scheme provided by the invention is as follows:
a phase sequence self-adaptive grid-connected control method of a chained SVG device comprises the following steps:
1) Acquiring three-phase line voltage input by a chained SVG device, and calculating to obtain a three-phase line voltage synchronous signal;
2) The three-phase voltage is input as a software phase-locked loop, and d and q axis components of the voltage output by the software phase-locked loop are utilized to judge the voltage phase sequence; if the voltage phase sequence is negative, regulating any two-phase voltage, and regulating the three-phase voltage to be positive;
3) Acquiring data of SVG three-phase current and three-phase synchronous voltage during high-voltage switching-on;
4) According to the data of the SVG three-phase current and the three-phase synchronous voltage during high-voltage brake charging, a corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage is obtained;
5) And according to the corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage, carrying out line sequence adjustment on the three-phase current acquisition signals output by the chained SVG device, calculating three-phase modulation waves, and correspondingly distributing the three-phase modulation waves to the three-phase converter chain.
As a further improvement of the above technical scheme:
in step 4), multiplying a certain synchronous voltage with each phase current respectively, and carrying out summation calculation according to the sampling point number of a fundamental wave period, if the summation of the products of the certain synchronous voltage and one phase current is positive and is larger than a set threshold value, the synchronous voltage is in phase with the input voltage of the phase.
The specific process of the step 4) is as follows:
multiplying the A synchronous voltage with A, B, C three-phase current output by a chained SVG device respectively, and carrying out summation calculation according to the sampling point number of a fundamental wave period, if the product accumulation sum of the A synchronous voltage and the A phase current is positive and is larger than a set threshold value, indicating that the A synchronous voltage is in phase with the A phase current, the A synchronous voltage and the A phase input voltage are correctly corresponding, otherwise, the A synchronous voltage and the A phase input voltage are not corresponding;
if the A synchronous voltage and the A phase input voltage are incorrectly corresponding, further judging whether the sum of the products and the accumulation of the A synchronous voltage and the B phase current is positive and larger than a set threshold value, if yes, indicating that the A synchronous voltage and the B phase input voltage are correctly corresponding, otherwise, not corresponding;
if the A synchronous voltage and the B phase input voltage are incorrectly corresponding, further judging whether the sum of the products and the accumulation of the A synchronous voltage and the C phase current is positive and is larger than a set threshold value, if so, indicating that the A synchronous voltage and the C phase input voltage are correctly corresponding;
if the synchronous voltage A and the input voltage C are not correctly corresponding, the synchronous voltages of the three phases are reversed, and the steps are re-executed;
multiplying the B-phase synchronous voltage with B, C, A three-phase current output by the chained SVG device respectively, and carrying out summation calculation according to the sampling point number of a fundamental wave period, if the product accumulation sum of the B-phase synchronous voltage and the B-phase current is positive and is larger than a set threshold value, indicating that the B-phase synchronous voltage is in phase with the B-phase current, the B-phase synchronous voltage and the B-phase input voltage are correctly corresponding, otherwise, the B-phase synchronous voltage and the B-phase input voltage are not corresponding;
if the B synchronous voltage and the B phase input voltage are incorrectly corresponding, further judging whether the sum of the products and the accumulation of the B synchronous voltage and the C phase current is positive and larger than a set threshold value, if yes, indicating that the B synchronous voltage and the C phase input voltage are correctly corresponding, otherwise, not corresponding;
if the B synchronous voltage and the C phase input voltage are incorrectly corresponding, further judging whether the sum of the products and the accumulation of the B synchronous voltage and the A phase current is positive and is larger than a set threshold value, if so, indicating that the B synchronous voltage and the A phase input voltage are correctly corresponding;
and finally, determining the corresponding relation between the synchronous voltage of the C and the input voltage of each phase, and finally obtaining the corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage.
After the step 5), the method further comprises a step 6) of adjusting the bus current offset angle and correcting the phase difference between the bus three-phase current and the phase sequence adjusted three-phase synchronous signal.
The bus current offset angle is 0 deg., -120 deg., or +120 deg..
In step 5), the specific process of correspondingly distributing the three-phase modulation wave to the three-phase converter chain is as follows: if the A synchronous voltage corresponds to the A phase input voltage, distributing the A phase modulation wave obtained by calculation to an A phase conversion chain; if the A synchronous voltage corresponds to the B phase input voltage, distributing the calculated A phase modulation wave to the B phase converter chain; if the A synchronous voltage corresponds to the C phase input voltage, distributing the A phase modulation wave obtained by calculation to a C phase conversion chain; similarly, B, C modulated waves can be distributed to the converter chains of the corresponding line sequence.
In step 5), the modulated signals of the respective phase inversion chains are superimposed on the modulated wave correction values of the respective phases to generate final modulated signals.
In the step 1), judging and setting whether the chained SVG device is of a direct hanging type or a buck type, calculating three-phase voltage by collecting input three-phase line voltage, and if the chained SVG device is of the direct hanging type, inputting the phase voltage to lag behind the bus line voltage by 30 degrees, wherein ua= (ub-uca)/3, ub= (ubc-uab)/3, uc= (uca-ubc)/3; if the voltage is reduced, the SVG input phase voltage is in phase with the bus line voltage,
the specific process of the step 2) is as follows: after the software phase-locked loop is stably phase-locked, if Ud is larger than a set threshold value and Uq is smaller than the set threshold value, judging that the voltage phase sequence is positive; otherwise, the voltage phase sequence is negative.
The invention also discloses a phase sequence self-adaptive grid-connected control system of the chained SVG device, which comprises the following steps:
the line phase conversion module is used for obtaining the three-phase line voltage input by the chained SVG device and calculating to obtain the three-phase line voltage;
the phase sequence detection and adjustment module is used for inputting the three-phase voltage as a software phase-locked loop and judging the phase sequence of the voltage by using d-axis components and q-axis components of the voltage output by the software phase-locked loop; if the voltage phase sequence is negative, regulating any two-phase voltage, and regulating the three-phase voltage to be positive;
the recording module is used for acquiring data of the SVG three-phase current and the three-phase synchronous voltage during high-voltage switching-on;
the line sequence judging module is used for obtaining a corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage according to the data of the SVG three-phase current and the three-phase synchronous voltage during high-voltage brake pressing charging;
and the modulation signal calculation module is used for carrying out line sequence adjustment on the three-phase current acquisition signals output by the chained SVG device according to the corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage, further calculating three-phase modulation waves and correspondingly distributing the three-phase modulation waves to the three-phase converter chain.
The invention further discloses a computer readable storage medium having stored thereon a computer program which, when run by a processor, performs the steps of the phase sequence adaptive grid-tie control method of a chained SVG device as described above.
The invention also discloses a computer device, which comprises a memory and a processor, wherein the memory is stored with a computer program, and the computer program executes the steps of the phase sequence self-adaptive grid-connected control method of the chained SVG device when being run by the processor.
Compared with the prior art, the invention has the advantages that:
according to the invention, aiming at the problem that the chain SVG device needs to be manually intervened to solve when the input voltage or the synchronous voltage is in wrong wiring, the corresponding relation between the synchronous voltage phase sequence and the secondary cable is automatically corrected through the steps of phase sequence detection, phase sequence adjustment, line sequence correction and the like, so that the automatic wrong sequence correction of an SVG control algorithm is realized, the device is enabled to normally run in a grid mode, the problem of wiring of the cable is solved without manual intervention, and the field debugging efficiency of equipment is improved.
Drawings
FIG. 1 is a flow chart of an embodiment of the method of the present invention.
FIG. 2 is a diagram of an embodiment of the method of the present invention in a specific application.
Detailed Description
The invention is further described below with reference to the drawings and specific examples.
As shown in fig. 1, the phase sequence adaptive grid-connected control method of the chained SVG device of the present embodiment includes the steps of:
1) Three-phase line voltage input by a chained SVG device is obtained through a bus voltage transformer, and a three-phase line voltage synchronous signal is obtained through calculation;
2) The method comprises the steps of inputting three-phase voltages as a software phase-locked loop, judging voltage phase sequences by using d-axis components and q-axis components of the voltages output by the software phase-locked loop, and adjusting any two-phase voltages to positive sequences if the voltage phase sequences are negative;
3) Acquiring data of SVG three-phase current and three-phase synchronous voltage during high-voltage switching-on;
4) According to the data of the SVG three-phase current and the three-phase synchronous voltage during high-voltage brake charging, a corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage is obtained;
5) And according to the corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage, carrying out line sequence adjustment on the three-phase current acquisition signals output by the chained SVG device, further calculating three-phase modulation waves, and then correspondingly distributing the three-phase modulation waves to a three-phase converter chain.
According to the invention, aiming at the problem that the chain SVG device needs to be manually intervened to solve when the input voltage or the synchronous voltage is in wrong wiring, the corresponding relation between the synchronous voltage phase sequence and the secondary cable is automatically corrected through the steps of phase sequence detection, phase sequence adjustment, line sequence correction and the like, so that the automatic wrong sequence correction of an SVG control algorithm is realized, the device is enabled to normally run in a grid mode, the problem of wiring of the cable is solved without manual intervention, and the field debugging efficiency of equipment is improved.
In a specific embodiment, in step 4), a certain synchronous voltage is multiplied by each phase current respectively, and the summation is performed according to the number of sampling points in a fundamental wave period, and if the sum of the products of the certain synchronous voltage and one phase current is positive and is greater than a set threshold value, the synchronous voltage is in phase with the phase input voltage. The specific process is as follows:
multiplying the synchronous voltage A with A, B, C three-phase current of the chained SVG device respectively and carrying out summation calculation according to the sampling point number of one fundamental wave period; if the sum of the products of the A-phase synchronous voltage and the A-phase current is positive and is larger than a set threshold value, the A-phase synchronous voltage and the A-phase current are indicated to be in phase, the A-phase synchronous voltage and the A-phase input voltage are correctly corresponding, otherwise, the A-phase synchronous voltage and the A-phase input voltage are not corresponding;
if the A synchronous voltage and the A phase input voltage are incorrectly corresponding, further judging that the sum of the products and the accumulation of the A synchronous voltage and the B phase current is positive and larger than a set threshold, if the sum is satisfied, indicating that the A synchronous voltage and the B phase input voltage are correctly corresponding, otherwise, the A synchronous voltage and the B phase input voltage are not corresponding;
if the A synchronous voltage and the B phase input voltage are incorrectly corresponding, further judging that the sum of the products and the accumulation of the A synchronous voltage and the C phase current is positive and is larger than a set threshold value, and if the sum is satisfied, indicating that the A synchronous voltage and the C phase input voltage are correctly corresponding;
if the synchronous voltage A and the input voltage C are not correctly corresponding, the synchronous voltages of the three phases are reversed, and the steps are re-executed;
multiplying the B synchronous voltage with B, C, A three-phase current of the chained SVG device respectively and carrying out summation calculation according to the sampling point number of one fundamental wave period; if the sum of the products of the B-phase synchronous voltage and the B-phase current is positive and is larger than a set threshold value, the B-phase synchronous voltage and the B-phase current are indicated to be in phase, the B-phase synchronous voltage and the B-phase input voltage are correctly corresponding, otherwise, the B-phase synchronous voltage and the B-phase input voltage are not corresponding;
if the B synchronous voltage and the B phase input voltage are incorrectly corresponding, further judging whether the sum of the products and the accumulation of the B synchronous voltage and the C phase current is positive and larger than a set threshold value, if yes, indicating that the B synchronous voltage and the C phase input voltage are correctly corresponding, otherwise, not corresponding;
if the B-phase synchronous voltage and the C-phase input voltage are incorrectly corresponding, further judging whether the sum of the products and the accumulation of the B-phase synchronous voltage and the A-phase current is positive and is larger than a set threshold value, if so, indicating that the A-phase synchronous voltage and the C-phase input voltage are correctly corresponding;
and finally, determining the corresponding relation between the synchronous voltage of the C and the input voltage of each phase, and finally obtaining the corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage.
In a specific embodiment, after step 5), step 6) is further included to adjust the bus current offset angle, so that the data displayed by the chained SVG device is consistent with the background or other data acquisition system, thereby correcting the phase difference between the bus three-phase current and the phase sequence adjusted three-phase synchronization signal. Wherein the bus current offset angle is 0 °, -120 °, or +120°.
In a specific embodiment, in step 5), the specific process of distributing the three-phase modulation wave to the three-phase converter chain correspondingly is: if the A synchronous voltage corresponds to the A phase input voltage, distributing the A phase modulation wave obtained by calculation to an A phase conversion chain; if the A synchronous voltage corresponds to the B phase input voltage, distributing the calculated A phase modulation wave to the B phase converter chain; if the A synchronous voltage corresponds to the C phase input voltage, distributing the A phase modulation wave obtained by calculation to a C phase conversion chain; similarly, B, C modulated waves can be distributed to the converter chains of the corresponding line sequence. Wherein the modulation signals of each phase of the converter chain are superimposed with the correction value of each phase of the modulation wave to generate a final modulation signal.
The invention also discloses a phase sequence self-adaptive grid-connected control system of the chained SVG device, which comprises the following steps:
the line phase conversion module is used for obtaining the three-phase line voltage input by the chained SVG device and calculating to obtain the three-phase line voltage;
the phase sequence detection and adjustment module is used for inputting three-phase voltage as a software phase-locked loop, judging the phase sequence of the voltage by using d-axis components and q-axis components of the voltage output by the software phase-locked loop, and adjusting any two-phase voltage to adjust the three-phase voltage to be positive sequence if the phase sequence of the voltage is negative;
the recording module is used for acquiring data of the SVG three-phase current and the three-phase synchronous voltage during high-voltage switching-on;
the line sequence judging module is used for obtaining a corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage according to the data of the SVG three-phase current and the three-phase synchronous voltage during high-voltage brake pressing charging;
and the modulation signal calculation module is used for carrying out line sequence adjustment on the three-phase current acquisition signals output by the chained SVG device according to the corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage, further calculating three-phase modulation waves and then correspondingly distributing the three-phase modulation waves to the three-phase converter chain.
The phase sequence self-adaptive grid-connected control system of the chained SVG device, which is disclosed by the invention, corresponds to the control method and has the advantages as described in the method.
The invention described above is described in further detail with reference to the following example:
1. the line/phase conversion module calculates three-phase voltage according to whether the SVG device is in direct hanging type or in step-down type by collecting input three-phase line voltage, if the SVG device is in direct hanging type, the SVG input phase voltage lags behind bus line voltage by 30 degrees, and u a ＝(u ab -u ca )/3、u b ＝(u bc -u ab )/3、u c ＝(u ca -u bc ) 3; if the voltage is reduced, the SVG input phase voltage is in phase with the bus line voltage,
2. the phase sequence judging module adopts d and q axis component low-pass filtering values of voltage output by the software phase-locked loop to judge the voltage phase sequence, after the software phase-locked loop is stably locked, if the voltage phase sequence is positive, ud is basically constant direct current, uq is basically zero, if the voltage phase sequence is negative, uq is not zero and contains double frequency alternating current components, accordingly, if Ud is larger than a set threshold value and Uq is smaller than the set threshold value, the voltage phase sequence can be judged to be positive, a phase sequence mark seq_flag=0, otherwise, the voltage phase sequence is negative, and a phase sequence mark seq_flag=1;
3. the phase sequence adjusting module adjusts the value of the three-phase voltage according to the value of the phase sequence mark, and if the seq_flag=0, u is caused to be A ＝u a 、u B ＝u b 、u C ＝u c If seq_flag=1, in principle, by changing any two-phase voltage, three-phase voltage can be adjusted to positive sequence, and u is given for simplification A ＝u b 、u B ＝u a 、u C ＝u c ；
4. The data recording module is used for recording the values of SVG three-phase charging current and three-phase synchronous phase voltage when the SVG branch circuit breaker is switched on and the value of any one phase charging current is larger than a set threshold value, setting a data recording mark, controlling the sampling frequency of the system to be 6.4kHz, namely 128 points are sampled in each power frequency period, and defining 6 arrays with the data width of 128 for recording the values of the SVG three-phase charging current and the three-phase synchronous phase voltage;
5. the line sequence judging module judges the line sequence according to the data of the data recording module, and because the three-phase charging currents are all active currents when the SVG is precharged, the three-phase charging currents are respectively in phase with the A, B, C three-phase input voltage. Therefore, the sequence relationship of the input voltage can be judged by judging whether the charging current is in phase with the synchronous voltage, and the specific judging method is as follows: multiplying the A synchronous voltage with A, B, C three-phase charging current of SVG and performing 128-point summation calculation, if the sum of the products of the A synchronous voltage and the A phase current is positive and is larger than a set threshold value, indicating that the A synchronous voltage is in phase with the A phase current, the A synchronous voltage and the A phase input voltage are correctly corresponding, phaseA_Flag=1; if the sum of the products of the A-phase synchronous voltage and the A-phase current does not meet the condition, further judging whether the sum of the products of the A-phase synchronous voltage and the B-phase current meets the set condition, if so, indicating that the A-phase synchronous voltage and the B-phase input voltage are correctly corresponding, wherein PhaseA_Flag=2; if the sum of the products of the A-phase synchronous voltage and the B-phase current does not meet the condition, further judging whether the sum of the products of the A-phase synchronous voltage and the C-phase current meets the set condition, if so, indicating that the A-phase synchronous voltage and the C-phase input voltage are correctly corresponding, wherein PhaseA_flag=3;
6. if the synchronous voltage A and the input voltage C are not correctly corresponding, the synchronous voltages of the three phases are reversed, and the step 5 is executed again;
7. after the phase sequence judgment is finished, continuing to perform phase sequence judgment according to the value of PhaseA_Flag, multiplying the phase B synchronous voltage by B, C phase current of SVG respectively and performing 128-point summation calculation if PhaseA_Flag=1, indicating that the phase B synchronous voltage and the phase B input voltage correctly correspond if the sum of the products of the phase B synchronous voltage and the phase B current meets a set condition, and further judging whether the sum of the products of the phase B synchronous voltage and the phase C current meets the set condition if the sum of the products of the phase B synchronous voltage and the phase B current does not meet the condition, and judging that the phase B synchronous voltage and the phase C input voltage correctly correspond if the sum of the products of the phase B synchronous voltage and the phase B current meets the set condition, wherein PhaseB_Flag=3; if PhaseA_Flag=2, multiplying the B-phase synchronous voltage with A, C phase current of SVG respectively and carrying out 128-point summation calculation, if the sum of the products of the B-phase synchronous voltage and the A-phase current meets the set condition, indicating that the B-phase synchronous voltage and the A-phase input voltage are correctly corresponding, phaseB_Flag=1, if the sum of the products of the B-phase synchronous voltage and the A-phase current does not meet the condition, further judging whether the sum of the products of the B-phase synchronous voltage and the C-phase current meets the set condition, if so, indicating that the B-phase synchronous voltage and the C-phase input voltage are correctly corresponding, and PhaseB_Flag=3; if PhaseA_Flag=3, multiplying the B-phase synchronous voltage with B, A phase current of SVG respectively and carrying out 128-point summation calculation, if the sum of the products of the B-phase synchronous voltage and the B-phase current meets a set condition, indicating that the B-phase synchronous voltage and the B-phase input voltage are correctly corresponding, phaseB_Flag=2, if the sum of the products of the B-phase synchronous voltage and the B-phase current does not meet the condition, further judging whether the sum of the products of the B-phase synchronous voltage and the A-phase current meets the set condition, if so, indicating that the B-phase synchronous voltage and the A-phase input voltage are correctly corresponding, and PhaseB_Flag=1;
8. a, B after the end of the phase input voltage sequence relationship determination, the C-phase input voltage sequence flag value can be calculated as shown in table 1;
TABLE 1 line sequence flag values
| PhaseA_Flag | PhaseB_Flag | PhaseC_Flag |
| 1 | 2 | 3 |
| 1 | 3 | 2 |
| 2 | 1 | 3 |
| 2 | 3 | 1 |
| 3 | 2 | 1 |
| 3 | 1 | 2 |
9. The line sequence adjusting module adjusts the value of the SVG three-phase current sampling value entering the current closed-loop control module according to the line sequence mark value, and if PhaseA_flag=1, i is the phase A A ＝i a If phasea_flag=2, i A ＝i b If phasea_flag=3, i A ＝i c The method comprises the steps of carrying out a first treatment on the surface of the For phase B, if phaseb_flag=1, i B ＝i a If PhaseB_Flag=2, then i B ＝i b If PhaseB_Flag=3, then i B ＝i c The method comprises the steps of carrying out a first treatment on the surface of the For phase C, if phasec_flag=1, i C ＝i a If PhaseC_Flag=2, then i C ＝i b If PhaseC_Flag=3, then i C ＝i c ；
10. The current closed-loop control module realizes reactive power and harmonic compensation algorithm, performs closed-loop control on SVG output current, and generates a three-phase modulation signal;
11. the three-phase modulation signal calculation module redistributes the three-phase modulation signal calculated and output by the current closed-loop control module according to the line sequence mark value, for the A phase, if PhaseA_Flag=1, the calculated A phase debugging wave is distributed to an A phase converter chain, phaseA_Flag=2, the A phase debugging wave is distributed to a B phase converter chain, phaseA_Flag=3, the A phase debugging wave is distributed to a C phase converter chain, and similarly, B, C phase modulation waves can be distributed to the converter chain corresponding to the line sequence; the modulation signals of each phase of converter chain are overlapped with the modulation wave correction value output by each phase of direct current equalizing control module to generate a final modulation signal;
12. because the phase sequence adjusting module only exchanges A, B phase voltage to realize phase sequence adjustment when the voltage is negative, a phase difference exists between a three-phase synchronous signal after phase sequence adjustment and a bus real synchronous signal, and the phase difference is 120 degrees below zero or 120 degrees below zero, so that bus reactive power calculation is influenced, and reactive power automatic compensation is influenced;
13. through the steps, the SVG device phase sequence self-adaptive grid-connected operation can be realized.
The embodiment of the invention also discloses a computer readable storage medium, wherein a computer program is stored on the computer readable storage medium, and the computer program executes the steps of the phase sequence self-adaptive grid-connected control method of the chained SVG device when being run by a processor. The embodiment of the invention further discloses a computer device which comprises a memory and a processor, wherein the memory is stored with a computer program, and the computer program executes the steps of the phase sequence self-adaptive grid-connected control method of the chained SVG device when being run by the processor. The present invention may be implemented by implementing all or part of the procedures in the methods of the embodiments described above, or by instructing the relevant hardware by a computer program, which may be stored in a computer readable storage medium, and which when executed by a processor, may implement the steps of the embodiments of the methods described above. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, executable files or in some intermediate form, etc. The computer readable medium may include: any entity or device capable of carrying computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth. The memory may be used to store computer programs and/or modules, and the processor performs various functions by executing or executing the computer programs and/or modules stored in the memory, and invoking data stored in the memory. The memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, memory, plug-in hard disk, smart Media Card (SMC), secure Digital (SD) Card, flash Card (Flash Card), at least one disk storage device, flash memory device, or other volatile solid state storage device, etc.
The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above examples, and all technical solutions belonging to the concept of the present invention belong to the protection scope of the present invention. It should be noted that modifications and adaptations to the invention without departing from the principles thereof are intended to be within the scope of the invention as set forth in the following claims.
Claims (11)
1. The phase sequence self-adaptive grid-connected control method of the chained SVG device is characterized by comprising the following steps of:
1) Acquiring three-phase line voltage input by a chained SVG device, and calculating to obtain a three-phase line voltage synchronous signal;
2) The method comprises the steps of inputting three-phase voltages as a software phase-locked loop, judging voltage phase sequences by using d-axis components and q-axis components of the voltages output by the software phase-locked loop, and adjusting any two-phase voltages to adjust the three-phase voltages to positive sequences if the voltage phase sequences are negative sequences;
3) Acquiring data of SVG three-phase current and three-phase synchronous voltage during high-voltage switching-on;
4) According to the data of the SVG three-phase current and the three-phase synchronous voltage during high-voltage brake charging, a corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage is obtained;
5) And according to the corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage, carrying out line sequence adjustment on the three-phase current acquisition signals output by the chained SVG device, calculating three-phase modulation waves, and correspondingly distributing the three-phase modulation waves to the three-phase converter chain.
2. The phase sequence adaptive grid-connected control method of a chained SVG device according to claim 1, wherein in step 4), a certain synchronous voltage is multiplied by each phase current, and summed according to the number of sampling points of a fundamental wave period, and if the sum of the products of the certain synchronous voltage and one phase current is positive and greater than a set threshold, the synchronous voltage is in phase with the phase input voltage.
3. The phase sequence adaptive grid-connected control method of the chained SVG device according to claim 2, wherein the specific process of the step 4) is as follows:
multiplying the A synchronous voltage with A, B, C three-phase current output by a chained SVG device respectively, and carrying out summation calculation according to the sampling point number of a fundamental wave period, if the product accumulation sum of the A synchronous voltage and the A phase current is positive and is larger than a set threshold value, indicating that the A synchronous voltage is in phase with the A phase current, the A synchronous voltage and the A phase input voltage are correctly corresponding, otherwise, the A synchronous voltage and the A phase input voltage are not corresponding;
if the A synchronous voltage and the A phase input voltage are incorrectly corresponding, further judging whether the sum of the products and the accumulation of the A synchronous voltage and the B phase current is positive and larger than a set threshold value, if yes, indicating that the A synchronous voltage and the B phase input voltage are correctly corresponding, otherwise, not corresponding;
if the A synchronous voltage and the B phase input voltage are incorrectly corresponding, further judging whether the sum of the products and the accumulation of the A synchronous voltage and the C phase current is positive and is larger than a set threshold value, if so, indicating that the A synchronous voltage and the C phase input voltage are correctly corresponding;
if the synchronous voltage A and the input voltage C are not correctly corresponding, the synchronous voltages of the three phases are reversed, and the steps are re-executed;
multiplying the B-phase synchronous voltage with B, C, A three-phase current output by the chained SVG device respectively, and carrying out summation calculation according to the sampling point number of a fundamental wave period, if the product accumulation sum of the B-phase synchronous voltage and the B-phase current is positive and is larger than a set threshold value, indicating that the B-phase synchronous voltage is in phase with the B-phase current, the B-phase synchronous voltage and the B-phase input voltage are correctly corresponding, otherwise, the B-phase synchronous voltage and the B-phase input voltage are not corresponding;
if the B synchronous voltage and the B phase input voltage are incorrectly corresponding, further judging whether the sum of the products and the accumulation of the B synchronous voltage and the C phase current is positive and larger than a set threshold value, if yes, indicating that the B synchronous voltage and the C phase input voltage are correctly corresponding, otherwise, not corresponding;
if the B synchronous voltage and the C phase input voltage are incorrectly corresponding, further judging whether the sum of the products and the accumulation of the B synchronous voltage and the A phase current is positive and is larger than a set threshold value, if so, indicating that the B synchronous voltage and the A phase input voltage are correctly corresponding;
and finally, determining the corresponding relation between the synchronous voltage of the C and the input voltage of each phase, and finally obtaining the corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage.
4. The phase sequence adaptive grid-connected control method of a chained SVG device according to claim 1, 2 or 3, further comprising step 6) of adjusting a bus current offset angle after step 5), thereby correcting a phase difference between a bus three-phase current and a phase sequence adjusted three-phase synchronization signal.
5. The phase sequence adaptive grid-connected control method of a chained SVG device according to claim 4, wherein the bus current offset angle is 0 °, -120 ° or +120°.
6. The phase sequence adaptive grid-connected control method of a chained SVG device according to claim 1, 2 or 3, wherein in step 5), the specific process of correspondingly distributing the three-phase modulation wave to the three-phase converter chain is as follows: if the A synchronous voltage corresponds to the A phase input voltage, distributing the A phase modulation wave obtained by calculation to an A phase conversion chain; if the A synchronous voltage corresponds to the B phase input voltage, distributing the calculated A phase modulation wave to the B phase converter chain; if the A synchronous voltage corresponds to the C phase input voltage, distributing the A phase modulation wave obtained by calculation to a C phase conversion chain; similarly, B, C modulated waves can be distributed to the converter chains of the corresponding line sequence.
7. The phase sequence adaptive grid-connected control method of a chained SVG device according to claim 6, wherein in step 5), the modulation signals of each phase inversion chain are superimposed with the modulation wave correction value of each phase to generate a final modulation signal.
8. The phase sequence adaptive grid-connected control method of a chained SVG device according to claim 1, 2 or 3, wherein in step 1), it is determined whether the chained SVG device is of direct hanging type or of buck type, the three-phase voltage is calculated from the three-phase line voltage input by collection, if the chained SVG device is of direct hanging type, the chained SVG device inputs a phase voltage with a lag of 30 DEG, u a ＝(u ab -u ca )/3、u b ＝(u bc -u ab )/3、u c ＝(u ca -u bc ) 3; if the voltage is reduced, the SVG input phase voltage is in phase with the bus line voltage,
9. the phase sequence self-adaptive grid-connected control system of the chained SVG device is characterized by comprising:
the line phase conversion module is used for obtaining the three-phase line voltage input by the chained SVG device and calculating to obtain the three-phase line voltage;
the phase sequence detection and adjustment module is used for inputting the three-phase voltage as a software phase-locked loop and judging the phase sequence of the voltage by using d-axis components and q-axis components of the voltage output by the software phase-locked loop; if the voltage phase sequence is negative, regulating any two-phase voltage, and regulating the three-phase voltage to be positive;
the recording module is used for acquiring data of the SVG three-phase current and the three-phase synchronous voltage during high-voltage switching-on;
the line sequence judging module is used for obtaining a corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage according to the data of the SVG three-phase current and the three-phase synchronous voltage during high-voltage brake pressing charging;
and the modulation signal calculation module is used for carrying out line sequence adjustment on the three-phase current acquisition signals output by the chained SVG device according to the corresponding line sequence relation between the three-phase synchronous voltage and the three-phase input voltage, calculating three-phase modulation waves and correspondingly distributing the three-phase modulation waves to the three-phase converter chain.
10. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being run by a processor, performs the steps of the phase sequence adaptive grid-tie control method of a chained SVG device as claimed in any one of claims 1 to 9.
11. A computer device comprising a memory and a processor, the memory having stored thereon a computer program, characterized in that the computer program, when run by the processor, performs the steps of the phase-sequence adaptive grid-tie control method of a chained SVG device as claimed in any one of claims 1 to 9.
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