CN111697624A - Bus voltage control method based on voltage prediction - Google Patents
Bus voltage control method based on voltage prediction Download PDFInfo
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- CN111697624A CN111697624A CN202010584655.3A CN202010584655A CN111697624A CN 111697624 A CN111697624 A CN 111697624A CN 202010584655 A CN202010584655 A CN 202010584655A CN 111697624 A CN111697624 A CN 111697624A
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- 238000000034 method Methods 0.000 title claims abstract description 20
- 239000003990 capacitor Substances 0.000 claims description 3
- 230000001629 suppression Effects 0.000 claims description 3
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 3
- 238000009825 accumulation Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000011217 control strategy Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/01—Arrangements for reducing harmonics or ripples
-
- 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
- H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/40—Arrangements for reducing harmonics
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
Abstract
A bus voltage control method based on voltage prediction relates to the technical field of bus voltage control of single-phase inverters. Assuming that the input power and the output power of the inverter are stable, the loss is not considered, the input power of the inverter is just equal to the output power of the inverter on the average value, the reason causing the frequency doubling fluctuation of the bus voltage is grid-connected alternating current power, an alternating current part of the grid-connected power is extracted, and the alternating current part is assumed to be the grid-connected alternating current power
This ac power induced bus voltage fluctuation can be calculated as follows to obtain a predicted bus voltage reference. By usingAfter the technical scheme is adopted, the invention has the beneficial effects that: the fast bus voltage control can be realized, the frequency multiplication ripple of the power grid is prevented from being brought into the current ring, and the size of the frequency multiplication ripple in the voltage ring can be effectively inhibited.
Description
Technical Field
The invention relates to the technical field of bus voltage control of single-phase inverters, in particular to a bus voltage control method based on voltage prediction.
Background
At present, double closed-loop control (voltage loop and current loop) is adopted on the AC side of a main single-phase grid-connected inverter, the voltage loop controls bus voltage, and the current loop controls grid-connected current. For the control of the voltage loop, the difference value between the reference bus voltage and the actual bus voltage is generally selected as the input of the controller, and is converted into the reference value of the grid-connected current through a PI controller, so as to be used as the input of the current loop. The double closed-loop control system can ensure stable bus voltage and stable power output.
For a single-phase inverter, because the output power inevitably has the fluctuation of grid frequency multiplication (100Hz, for 50Hz grid), even if the input power of the inverter is constant, a grid frequency multiplication ripple wave is always generated on the bus voltage, which has adverse effect on the control of the voltage loop. For the control of the voltage loop, it is desirable to achieve a fast power response to cope with the power variation, and to filter out the ripple of the grid frequency multiplication from being introduced into the current loop, which is contradictory to the conventional control strategy. In order to achieve a fast response characteristic, the cut-off frequency of the controller must be increased, thus causing bus ripple to be introduced into the current loop.
Disclosure of Invention
The invention aims to provide a bus voltage control method based on voltage prediction aiming at the defects and shortcomings of the prior art, which can realize quick bus voltage control, avoid the frequency multiplication ripple of a power grid from being brought into a current loop and effectively inhibit the size of the frequency multiplication ripple in the voltage loop.
In order to achieve the purpose, the invention adopts the following technical scheme: the bus voltage control method based on voltage prediction comprises the following steps of:
assuming that the input power and the output power of the inverter are stable, the loss is not considered, the input power of the inverter is just equal to the output power of the inverter on the average value, the reason causing the frequency doubling fluctuation of the bus voltage is grid-connected alternating current power, an alternating current part of the grid-connected power is extracted, and the alternating current part is assumed to be the grid-connected alternating current power
Then the bus voltage fluctuation caused by this ac power can be calculated as follows:
thereby, a predicted bus voltage reference value can be obtained. Wherein C is the capacitance value of the bus capacitor, U is the bus voltage, and U is the average value of the bus voltage.
Furthermore, the band-pass filter needs to be designed based on the current power grid frequency, the frequency given by the phase-locked loop is fed back to the band-pass filter to realize dynamic adjustment in consideration of the fluctuation of the actual power grid frequency, and parameters can be adjusted in real time according to the power grid frequency to achieve the best suppression effect.
After the technical scheme is adopted, the invention has the beneficial effects that: the fast bus voltage control can be realized, the frequency multiplication ripple of the power grid is prevented from being brought into the current ring, and the size of the frequency multiplication ripple in the voltage ring can be effectively inhibited; comparing the harmonic content of the grid-connected current reference waveform using the conventional control method and the bus voltage control method based on voltage prediction, it can be seen that the harmonic content reaches 6% when the conventional method is used, and the harmonic content is reduced to about 0.3% when the bus voltage control method based on voltage prediction is used. This shows that the bus voltage control method based on voltage prediction can effectively suppress the magnitude of the frequency multiplication ripple in the voltage loop.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic diagram of a conventional voltage loop control loop;
FIG. 2 is a schematic diagram of a bus voltage control method based on voltage prediction;
FIG. 3 is a block diagram of a system in which the control method of the present invention is updated;
FIG. 4 is a graphical representation of harmonic content using a conventional control scheme;
FIG. 5 is a graphical illustration of harmonic content using a bus voltage control method based on voltage prediction.
Detailed Description
Referring to fig. 1 to 5, the technical solution adopted by the present embodiment is: the bus voltage control method based on voltage prediction has the following principle:
assuming that the input power and the output power of the inverter are stable, the loss is not considered, the input power of the inverter is just equal to the output power of the inverter on the average value, the reason causing the frequency doubling fluctuation of the bus voltage is grid-connected alternating current power, an alternating current part of the grid-connected power is extracted, and the alternating current part is assumed to be the grid-connected alternating current power
Then the bus voltage fluctuation caused by this ac power can be calculated as follows:
thereby, a predicted bus voltage reference value can be obtained. Wherein C is the capacitance value of the bus capacitor, U is the bus voltage, and U is the average value of the bus voltage.
Furthermore, the band-pass filter needs to be designed based on the current power grid frequency, the frequency given by the phase-locked loop is fed back to the band-pass filter to realize dynamic adjustment in consideration of the fluctuation of the actual power grid frequency, and parameters can be adjusted in real time according to the power grid frequency to achieve the best suppression effect.
Comparing the harmonic content of the grid-connected current reference waveform using the conventional control method and the bus voltage control method based on voltage prediction, it can be seen that the harmonic content reaches 6% when the conventional method is used, and the harmonic content is reduced to about 0.3% when the bus voltage control method based on voltage prediction is used. This shows that the bus voltage control method based on voltage prediction can effectively suppress the magnitude of the frequency multiplication ripple in the voltage loop.
The method also comprises two design steps: 1. integrator design: the integrator cannot use the conventional 1/s, otherwise it introduces accumulation error, and 1/(s +) is used instead of the integrator to avoid accumulation error. 2. Designing a voltage loop controller: a traditional PI regulator is adopted, and the cut-off frequency of the PI regulator is set according to the requirements of dynamic performance.
The above description is only for the purpose of illustrating the technical solutions of the present invention and not for the purpose of limiting the same, and other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention should be covered within the scope of the claims of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (1)
1. A bus voltage control method based on voltage prediction is characterized in that: it comprises the following steps:
assuming that the input and output power of the inverter are stable, the input power of the inverter is equal to the output power of the inverter on the average value, and the loss is not considered, thereby causing the frequency multiplication of the bus voltageThe reason for the fluctuation is the grid-connected AC power, and the AC part of the grid-connected power is extracted, and is assumed to be
Then the bus voltage fluctuation caused by this ac power can be calculated as follows:
thus, a predicted bus voltage reference value can be obtained; c is the capacitance value of the bus capacitor, U is the bus voltage, and U is the average value of the bus voltage;
furthermore, the band-pass filter needs to be designed based on the current power grid frequency, the frequency given by the phase-locked loop is fed back to the band-pass filter to realize dynamic adjustment in consideration of the fluctuation of the actual power grid frequency, and parameters can be adjusted in real time according to the power grid frequency to achieve the best suppression effect.
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| CN202010584655.3A CN111697624A (en) | 2020-06-24 | 2020-06-24 | Bus voltage control method based on voltage prediction |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113619559A (en) * | 2021-08-17 | 2021-11-09 | 合肥巨一动力系统有限公司 | Motor voltage control method and device for hybrid electric vehicle |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103487652A (en) * | 2013-09-03 | 2014-01-01 | 电子科技大学 | Frequency self-adaptive real-time fractional harmonic wave detection method |
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- 2020-06-24 CN CN202010584655.3A patent/CN111697624A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103487652A (en) * | 2013-09-03 | 2014-01-01 | 电子科技大学 | Frequency self-adaptive real-time fractional harmonic wave detection method |
Non-Patent Citations (3)
| Title |
|---|
| 张占锋;樊艳芳;王一波;王环;: "基于双二阶广义积分锁频环的光伏并网发电系统仿真研究" * |
| 戴朋岑: "超级电容器组在并网变流器中的应用研究" * |
| 谢聪;吴新开;雷雅云;: "基于双二阶广义积分锁相的风电并网系统仿真" * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113619559A (en) * | 2021-08-17 | 2021-11-09 | 合肥巨一动力系统有限公司 | Motor voltage control method and device for hybrid electric vehicle |
| CN113619559B (en) * | 2021-08-17 | 2023-01-24 | 合肥巨一动力系统有限公司 | Motor voltage control method and device for hybrid electric vehicle |
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Application publication date: 20200922 |