CN112886622B - Novel voltage transient problem treatment device and treatment method thereof - Google Patents

Novel voltage transient problem treatment device and treatment method thereof Download PDF

Info

Publication number
CN112886622B
CN112886622B CN202110331466.XA CN202110331466A CN112886622B CN 112886622 B CN112886622 B CN 112886622B CN 202110331466 A CN202110331466 A CN 202110331466A CN 112886622 B CN112886622 B CN 112886622B
Authority
CN
China
Prior art keywords
voltage
phase
output end
power grid
bridge
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110331466.XA
Other languages
Chinese (zh)
Other versions
CN112886622A (en
Inventor
王森
王萍
周大磊
侯飞
高鹏
王启华
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Suzhou Actionpower Power Supply Technology Co ltd
Original Assignee
Suzhou Actionpower Power Supply Technology Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Suzhou Actionpower Power Supply Technology Co ltd filed Critical Suzhou Actionpower Power Supply Technology Co ltd
Priority to CN202110331466.XA priority Critical patent/CN112886622B/en
Publication of CN112886622A publication Critical patent/CN112886622A/en
Application granted granted Critical
Publication of CN112886622B publication Critical patent/CN112886622B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • 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
    • H02J3/001—Methods to deal with contingencies, e.g. abnormalities, faults or failures
    • H02J3/00125—Transmission line or load transient problems, e.g. overvoltage, resonance or self-excitation of inductive loads

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)
  • Ac-Ac Conversion (AREA)

Abstract

The invention discloses a novel voltage transient problem treatment device and a treatment method thereof, the treatment device comprises a single-phase H-bridge inverter, the positive output end of the single-phase H-bridge inverter is connected with the positive output end and the negative output end of a power grid through a bidirectional thyristor SCR, a load is connected between the positive output end and the negative output end of the single-phase H-bridge inverter, the single-phase H-bridge inverter comprises two bridge arms, each bridge arm is formed by connecting an upper IGBT device and a lower IGBT device in series and an anti-parallel diode thereof, the connecting point of the upper IGBT device and the lower IGBT device in each bridge arm is the output end of the bridge arm, the output end of one bridge arm in the two bridge arms is connected with the positive output end of the power grid, the output end of the other bridge arm is connected with the negative output end of the power grid, the alternating current side of the single-phase H-bridge inverter comprises an inversion inductor and a filter capacitor, and a direct current bus is provided with a bus capacitor and an energy storage device. The treatment device obviously reduces the topological stage number, simplifies the control scheme, and has low cost and high equipment operation reliability.

Description

Novel voltage transient problem treatment device and treatment method thereof
Technical Field
The invention relates to the field of power quality treatment, in particular to a novel voltage transient problem treatment device and a treatment method thereof.
Background
With the continuous development of economy, the load in the power distribution network is more and more complicated, the characteristic changes are various, and the voltage transient quality problem can be introduced into the power distribution network by the continuously increased nonlinear loads and the problems of lightning stroke, operation overvoltage, distribution network short circuit and the like. Such as voltage flicker, voltage sag, voltage interruption, voltage sag, etc. At present, a plurality of high-precision equipment in the semiconductor industry, the automobile manufacturing industry and the medical industry have higher and higher requirements on the quality of a power grid, particularly the voltage transient quality problem. The influence of the voltage transient quality problem on the above industries is more and more concerned by corresponding manufacturers and industries.
For years, one mode is to adopt a UPS scheme for treating the voltage transient quality problem, the UPS is taken as a standby power system and is always favored by various industries, but for the voltage transient quality problem, the occurrence probability is very random, the time is very short, the investment cost and the maintenance cost of the UPS are too high, and the UPS is not the most reasonable scheme; the other mode is that a series compensation scheme is adopted, a voltage source is connected in series into the power grid, and when the power grid has a voltage transient quality problem, the series compensation device compensates a gap or impact of the power grid voltage, so that the voltage of a rear-stage load is ensured to be normal. Compared with the first scheme, the scheme is low in cost and good in effect, but the series compensation scheme always needs a rectifying part to store energy for the direct-current bus, the inversion voltage of the other inversion part is connected in series to the power grid for compensation, a two-stage topological scheme is needed, namely the conventional scheme of rectifying, storing and inverting is needed, and the increase of the topological stage number can lead to the complexity of control and the improvement of the fault rate. Meanwhile, the conventional rectification and inversion adopt a voltage + current double-loop control scheme, so that for equipment for treating the voltage sag problem, the running time of the equipment is short, and the control scheme is complex. How to solve the above problems, adopting a simple and effective scheme to solve the voltage transient quality problem is the matter that those skilled in the art are trying to solve.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a novel voltage transient problem treatment device, which reduces the number of topological stages, is simple in control process, solves the transient quality problem of the power grid voltage and has low cost compared with the conventional series compensation scheme.
In order to achieve the purpose, the invention adopts the technical scheme that: a novel voltage transient problem treatment device comprises a single-phase H-bridge inverter, wherein the positive output end of the single-phase H-bridge inverter is connected with the positive output end and the negative output end of a power grid through a bidirectional thyristor SCR, the negative output end of the single-phase H-bridge inverter is connected with the negative output end of the power grid, a load is connected between the positive output end and the negative output end of the single-phase H-bridge inverter, the single-phase H-bridge inverter comprises two bridge arms, each bridge arm is formed by connecting an upper IGBT device, a lower IGBT device and an anti-parallel diode thereof in series, and the connecting point of the upper and lower IGBT devices in each bridge arm is the output end of the bridge arm, the output end of one of the two bridge arms is connected with the positive output end of the power grid, the output end of the other bridge arm is connected with the negative output end of the power grid, the alternating current side of the single-phase H-bridge inverter comprises an inverter inductor and a filter capacitor, and a bus capacitor and an energy storage device are arranged on a direct current bus of the single-phase H-bridge inverter.
As a specific implementation manner, the inverter inductor is connected in series to the output end of the bridge arm connected to the positive output end of the power grid, one end of the filter capacitor is connected to the output end of the inverter inductor, and the other end of the filter capacitor is connected to the output end of the other bridge arm.
The invention also aims to provide a treatment method of the novel voltage transient problem treatment device, which comprises the following steps:
1) when the power grid is normal:
11) the bidirectional thyristor SCR is put into operation, the load is electrified, and the single-phase H-bridge inverter naturally rectifies;
12) the single-phase H-bridge inverter is operated in a grid-connected mode in a voltage source mode, the voltage of the direct-current bus is stabilized, and energy is stored for the direct-current bus energy storage device;
2) when the power grid is abnormal:
21) the bidirectional thyristor SCR cuts off the connection of a power grid, a single-phase H-bridge inverter and a load;
22) the single-phase H-bridge inverter is seamlessly switched into a voltage source inversion mode, stable single-phase 220V voltage is output and provided for a load, if the power grid is recovered to be normal, the step 23) is carried out, and if the power grid is not recovered to be normal, the step 24) is carried out;
23) the power grid is recovered to be normal, the single-phase H-bridge inverter locks the phase of the power grid voltage, the phase of the amplitude of the inverter output is adjusted until the phase amplitude of the inverter output is consistent with that of the power grid voltage, then the bidirectional thyristor SCR is put into the single-phase H-bridge inverter, the single-phase H-bridge inverter is switched to a voltage source grid-connected operation mode, and the energy of the direct-current bus energy storage device is supplemented;
24) when the power grid is not recovered to be normal, the energy of the energy storage device on the direct-current bus of the single-phase H-bridge inverter can be gradually reduced until the energy consumption is finished, and the equipment stops running.
As a specific implementation, the specific control process of step 12) is as follows:
121) the voltage phase angle omega is obtained by adopting a soft phase-locked loop to lock the phase of the power grid voltage 0 t；
122) The current output by the regulator of the bus voltage loop is used as the active current I required by the energy storage device P ；
123) For a voltage source grid-connected control mode, the absorption of active current is realized by controlling the phase angle difference between the inversion voltage and the grid voltage, and the specific formula is as follows:
Figure BDA0002996162430000031
wherein, X L Is the inductive reactance of the inverter inductor, R is the parasitic resistance of the inverter inductor, U L The voltage is an inversion voltage, Us is a power grid voltage, and an offset angle delta is obtained through the formula;
124) peak value of the grid voltage multiplied by sin (ω) 0 t + δ) to obtain a given U of the voltage loop oref And the storage of bus energy is realized through the closed loop of the voltage loop.
As a specific embodiment, the specific control process in step 22) is as follows:
221) the grid voltage is abnormal, the grid voltage cannot be phase-locked at the moment, and the voltage phase angle omega t is set automatically;
222) disconnecting the bus voltage ring and resetting the controller;
223) multiplying the self-set peak value of the power grid voltage by sin (ω t) to obtain the set U of the voltage ring oref And the control of the inversion voltage is realized through the closed loop of the voltage loop, and the normal operation of the load is supported.
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:
1) the novel voltage transient problem treatment device adopts a topological structure connected in parallel on a power grid, and compared with a conventional series topology, the novel voltage transient problem treatment device reduces a primary energy storage power electronic topology, and is simpler in structure;
2) the novel voltage transient problem treatment device adopts a single-ring control mode of directly closing a loop by output voltage, simultaneously solves the problems of direct current bus energy storage when the power grid is normal and voltage source operation when the power grid is abnormal, and compared with the traditional double-ring control scheme, the novel voltage transient problem treatment device has the advantages that the control loop is simple, inductive current does not need to be collected, and the cost is reduced; the novel device can well solve the transient quality problem of the power grid voltage, and is low in cost and simple to control compared with a conventional series compensation scheme.
Drawings
FIG. 1 is a topological diagram of the novel voltage transient problem abatement device of the present invention;
FIG. 2 is a block diagram of grid-connected control of the novel voltage transient problem management device according to the present invention;
fig. 3 is an off-grid control block diagram of the novel voltage transient problem treatment device according to the present invention.
Detailed Description
The technical solution of the present invention is further explained with reference to the drawings and the specific embodiments.
A novel voltage transient problem treatment device, which is shown in figure 1 and comprises a single-phase H-bridge inverter, the positive output end of the single-phase H-bridge inverter is connected with the positive output end and the negative output end of the power grid through a bidirectional thyristor SCR, the load is connected between the positive output end and the negative output end of the single-phase H-bridge inverter, the single-phase H-bridge inverter comprises two bridge arms, each bridge arm is formed by connecting an upper IGBT device and a lower IGBT device in series and an anti-parallel diode thereof, and the connecting point of the upper IGBT device and the lower IGBT device in each bridge arm is the output end of the bridge arm, the output end of one of the two bridge arms is connected with the positive output end of the power grid, the output end of the other bridge arm is connected with the negative output end of the power grid, the alternating current side of the single-phase H-bridge inverter comprises an inverter inductor and a filter capacitor, and a direct current bus of the single-phase H-bridge inverter is provided with a bus capacitor and an energy storage device.
The inverter inductor is connected in series with the output end of the bridge arm connected with the positive output end of the power grid, one end of the filter capacitor is connected with the output end of the inverter inductor, and the other end of the filter capacitor is connected with the output end of the other bridge arm.
The embodiment also provides a treatment method of the novel voltage transient problem treatment device, which comprises the following steps:
1) when the power grid is normal:
11) the SCR of the bidirectional thyristor is put into use, the load is electrified, and the single-phase H-bridge inverter naturally rectifies;
12) the method comprises the following steps that a single-phase H-bridge inverter runs in a grid-connected mode in a voltage source mode, the voltage of a direct-current bus is stabilized, and energy is stored in a direct-current bus energy storage device, and a specific control block diagram is shown in figure 2 and comprises the following steps;
121) the voltage phase angle omega is obtained by adopting a soft phase-locked loop to lock the phase of the power grid voltage 0 t；
122) The current output by the regulator of the bus voltage loop is used as the active current I required by the energy storage device P ；
123) For a voltage source grid-connected control mode, the absorption of active current is realized by controlling the phase angle difference between the inversion voltage and the grid voltage, and the specific formula is as follows:
Figure BDA0002996162430000041
wherein, X L Is the inductive reactance of the inverter inductor, R is the parasitic resistance of the inverter inductor, U L The inversion voltage is used, Us is the power grid voltage, and the offset angle delta is obtained through the formula;
124) peak value of the grid voltage multiplied by sin (ω) 0 t + δ) to obtain a given U of the voltage loop oref And the storage of bus energy is realized through the closed loop of the voltage loop.
2) When the power grid is abnormal:
21) the bidirectional thyristor SCR cuts off the connection of a power grid, a single-phase H-bridge inverter and a load;
22) the single-phase H-bridge inverter is seamlessly switched into a voltage source inversion mode, stable single-phase 220V voltage is output and provided for a load, a specific control block diagram is shown in figure 3, and the method comprises the following steps;
221) the grid voltage is abnormal, the grid voltage cannot be phase-locked at the moment, and the voltage phase angle omega t is set automatically;
222) disconnecting the bus voltage ring and resetting the controller;
223) multiplying the self-set peak value of the power grid voltage by sin (ω t) to obtain the set U of the voltage ring oref The control of the inversion voltage is realized through the closed loop of the voltage loop, and the normal operation of the load is supported;
23) if the power grid is recovered to be normal after the step 22), the single-phase H-bridge inverter locks the phase of the power grid voltage, adjusts the phase of the amplitude of the inverted output until the phase amplitude of the inverted output is consistent with that of the power grid voltage, and then puts in a bidirectional thyristor SCR (silicon controlled rectifier), the single-phase H-bridge inverter is switched to a voltage source grid-connected operation mode, and the energy of the direct-current bus energy storage device is supplemented;
24) and if the power grid is not recovered to be normal after the step 22), gradually reducing the energy of the energy storage device at the direct current side of the single-phase H-bridge inverter until the energy consumption is finished, and stopping the operation of the equipment.
The treatment device adopts a scheme of connecting inverters in parallel, reduces the topological stage number, and simplifies the control scheme, which specifically comprises the following steps:
1. the operation mode is as follows: A. when the power grid is normal, the thyristor is conducted, the inverter is started in a voltage source grid-connected control mode, the direct-current bus voltage is stabilized, and energy is stored for a direct-current bus capacitor or other energy storage devices; B. when the transient quality problem of the power grid occurs, the thyristor is cut off, and the inverter outputs the inverted voltage in a voltage source mode to provide voltage for the load. The inverters under two working conditions operate in a voltage source mode, seamless switching can be realized, and the voltage supplied to a load almost has no transient abnormal process;
2. the control mode is as follows: the sampling of inductive current is saved by adopting the control mode of a single voltage ring, meanwhile, the control is simplified, and when the power grid is normal, the absorption of active current is realized by controlling the phase angle difference between the output voltage of a bridge arm and the power grid, and energy is stored for a direct-current bus energy storage element; when the power grid is abnormal, a simple single voltage ring control mode is adopted, voltage with the same amplitude as the power grid voltage is output in an inverted mode, and the power supply of the load is guaranteed to be normal.
The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered in the protection scope of the present invention.

Claims (2)

1. A novel voltage transient problem treatment device is characterized by comprising a single-phase H-bridge inverter, the positive output end of the single-phase H-bridge inverter is connected with the positive output end of the power grid through a bidirectional thyristor SCR, the negative output end of the single-phase H-bridge inverter is connected with the negative output end of the power grid, the load is connected between the positive output end and the negative output end of the single-phase H-bridge inverter, the single-phase H-bridge inverter comprises two bridge arms, each bridge arm is formed by connecting an upper IGBT device, a lower IGBT device and an anti-parallel diode thereof in series, and the connecting point of the upper and lower IGBT devices in each bridge arm is the output end of the bridge arm, the output end of one of the two bridge arms is connected with the positive output end of the power grid, the output end of the other bridge arm is connected with the negative output end of the power grid, the alternating current side of the single-phase H-bridge inverter comprises an inverter inductor and a filter capacitor, and a bus capacitor and an energy storage device are arranged on a direct current bus of the single-phase H-bridge inverter;
adopt novel voltage transient state problem administers device's improvement step as follows:
1) when the power grid is normal:
11) the SCR of the bidirectional thyristor is put into use, the load is electrified, and the single-phase H-bridge inverter naturally rectifies;
12) the single-phase H bridge inverter is in grid-connected operation in a voltage source mode, stabilizes direct current bus voltage, and stores energy for a direct current bus energy storage device, and the method comprises the following specific steps:
121) the voltage of the power grid is phase-locked by a soft phase-locked loop to obtain a voltage phase angle omega 0 t；
122) The current output by the regulator of the bus voltage loop is used as the active current I required by the energy storage device p ；
123) For a voltage source grid-connected control mode, the absorption of active current is realized by controlling the phase angle difference between the inversion voltage and the grid voltage, and the specific formula is as follows:
Figure FDA0003755876010000011
wherein, X L Is the inductive reactance of the inverter inductor, R is the parasitic resistance of the inverter inductor, U L The voltage is an inversion voltage, Us is a power grid voltage, and an offset angle delta is obtained through the formula;
124) peak value of the grid voltage multiplied by sin (ω) 0 t + delta) to obtain a given U of the voltage ring oref The storage of bus energy is realized through the closed loop of the voltage loop;
2) when the power grid is abnormal:
21) the bidirectional thyristor SCR cuts off the connection of a power grid, a single-phase H-bridge inverter and a load;
22) the single-phase H-bridge inverter is seamlessly switched into a voltage source inversion mode, stable single-phase 220V voltage is output and provided for a load, if the power grid is recovered to be normal, the step 23) is carried out, and if the power grid is not recovered to be normal, the step 24) is carried out, and the specific steps are as follows:
221) the grid voltage is abnormal, the grid voltage cannot be phase-locked at the moment, and the voltage phase angle omega t is set automatically;
222) disconnecting the bus voltage ring and resetting the controller;
223) multiplying the self-set peak value of the power grid voltage by sin (ω t) to obtain the set U of the voltage ring oref The control of the inversion voltage is realized through the closed loop of the voltage loop, and the normal operation of the load is supported;
23) the power grid is recovered to be normal, the single-phase H-bridge inverter locks the phase of the power grid voltage, the phase of the amplitude of the inverter output is adjusted until the phase amplitude of the inverter output is consistent with that of the power grid voltage, then the bidirectional thyristor SCR is put into the single-phase H-bridge inverter, the single-phase H-bridge inverter is switched to a voltage source grid-connected operation mode, and the energy of the direct-current bus energy storage device is supplemented;
24) when the power grid is not recovered to be normal, the energy of the energy storage device on the direct-current bus of the single-phase H-bridge inverter is gradually reduced until the energy consumption is finished, and the equipment stops running.
2. The novel voltage transient problem treatment device according to claim 1, wherein the inverter inductor is connected in series with the output end of the bridge arm connected with the positive output end of the power grid, one end of the filter capacitor is connected with the output end of the inverter inductor, and the other end of the filter capacitor is connected with the output end of the other bridge arm.
CN202110331466.XA 2021-03-29 2021-03-29 Novel voltage transient problem treatment device and treatment method thereof Active CN112886622B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110331466.XA CN112886622B (en) 2021-03-29 2021-03-29 Novel voltage transient problem treatment device and treatment method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110331466.XA CN112886622B (en) 2021-03-29 2021-03-29 Novel voltage transient problem treatment device and treatment method thereof

Publications (2)

Publication Number Publication Date
CN112886622A CN112886622A (en) 2021-06-01
CN112886622B true CN112886622B (en) 2022-09-13

Family

ID=76040902

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110331466.XA Active CN112886622B (en) 2021-03-29 2021-03-29 Novel voltage transient problem treatment device and treatment method thereof

Country Status (1)

Country Link
CN (1) CN112886622B (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101892123B1 (en) * 2017-06-02 2018-08-30 서울과학기술대학교 산학협력단 Hybrid Uninterruptible Power System Capable Of Being Connected To Unbalanced Grid
CN109119990A (en) * 2018-10-25 2019-01-01 南京赫曦电气有限公司 A kind of low cost is administered network voltage and temporarily drop and the device and method of short interruptions

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2002246920A1 (en) * 2000-10-27 2002-08-06 Emerson Electric Co. Uninterruptible power supply
CN203589767U (en) * 2013-10-18 2014-05-07 西安爱科赛博电气股份有限公司 Power supply vehicle power supply system
CN107732921B (en) * 2017-11-17 2020-10-02 东南大学 Electric energy quality composite control device based on nine-switch-tube inverter and working method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101892123B1 (en) * 2017-06-02 2018-08-30 서울과학기술대학교 산학협력단 Hybrid Uninterruptible Power System Capable Of Being Connected To Unbalanced Grid
CN109119990A (en) * 2018-10-25 2019-01-01 南京赫曦电气有限公司 A kind of low cost is administered network voltage and temporarily drop and the device and method of short interruptions

Also Published As

Publication number Publication date
CN112886622A (en) 2021-06-01

Similar Documents

Publication Publication Date Title
EP3514936B1 (en) Hybrid dc converter for offshore wind farm
CN111525826B (en) Modular capacitor phase-change current converter and method
CN104184151B (en) A kind of dynamic electric voltage recovery device realizing the different operational mode of microgrid and take over seamlessly
CN109830978A (en) A kind of soft lineal system of wind-powered electricity generation having the automatic ride-through capability of failure and control method
CN205248805U (en) Novel DVR voltage compensation device
CN103219738A (en) Direct current transmission system based on three-pole type structure
CN107196312B (en) L C network switch parallel connection type unified power quality controller and control method thereof
CN1332489C (en) Multifunctional adjuster for quality of voltage in low voltage system
CN109995043B (en) Novel flexible multi-state switch device and control method
CN106899025A (en) A kind of comprehensive compensation type alternating current steady voltage plug
CN106711943A (en) Protection device and method for distributed series-coupled power flow controller
Guo et al. An overview of series-connected power electronic converter with function extension strategies in the context of high-penetration of power electronics and renewables
CN104218575A (en) UPQC (unified power quality conditioner) based on SCR (silicon controlled rectifier) and energy storage
CN112803462A (en) Forced turn-off method of static transfer switch based on energy storage converter
CN113394791A (en) Parallel DVR bypass thyristor rapid cut-off control method
CN110808604B (en) Three-port energy control device based on MMC structure
CN201178308Y (en) Voltage disturbing compensating apparatus
CN206673592U (en) A kind of comprehensive compensation type alternating current steady voltage plug
CN112886622B (en) Novel voltage transient problem treatment device and treatment method thereof
Liang et al. The influence of high permeability distributed photovoltaic access on power grid
CN104104104A (en) Method of automatic switching between power generation mode and SVG mode for photovoltaic inverter
CN110137975A (en) New electric energy quality controller and its control method based on current source inverter
CN116191482A (en) Control system and method for unbalanced load of three-level voltage restorer
CN212676896U (en) Bidirectional power conversion grid-connected dynamic voltage compensation system
CN204928185U (en) Current -limiting formula unified power flow controller based on many level of modularization transverter

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant