CN113725894B - Multi-mode seamless switching photovoltaic inverter controller and photovoltaic inverter system - Google Patents
Multi-mode seamless switching photovoltaic inverter controller and photovoltaic inverter system Download PDFInfo
- Publication number
- CN113725894B CN113725894B CN202110902897.7A CN202110902897A CN113725894B CN 113725894 B CN113725894 B CN 113725894B CN 202110902897 A CN202110902897 A CN 202110902897A CN 113725894 B CN113725894 B CN 113725894B
- Authority
- CN
- China
- Prior art keywords
- inverter
- grid
- voltage
- value
- phase
- 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
Links
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
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
- H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
-
- 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
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
-
- 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
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The embodiment of the invention relates to the technical field of power distribution network inverters, and discloses a multi-mode seamless switching photovoltaic inverter controller and a photovoltaic inverter system. The multimode seamless switching photovoltaic inverter controller comprises: the controller is used for controlling the photovoltaic inverter to operate and controlling the photovoltaic inverter to switch working modes, wherein the working modes of the photovoltaic inverter comprise a grid-connected mode and an off-grid mode; when the grid-connected mode is switched to the off-grid mode, the controller locks the phase detected during off-grid, generates a continuously-changed phase, and sends a current instruction of the grid-connected mode to the voltage outer loop PI regulator of the off-grid mode; when the off-grid mode is switched to the grid-connected mode, the controller controls the phase output of the photovoltaic inverter to continuously change before and after switching.
Description
Technical Field
The invention relates to the technical field of power distribution network inverters, in particular to a multimode seamless switching photovoltaic inverter controller and a photovoltaic inverter system.
Background
Along with the development of social economy, the modern power industry has stepped into a large-unit, ultra-high-voltage and alternating-current/direct-current mixed large power grid era, but as fossil fuels are gradually exhausted and environmental pressure is gradually increased, a renewable energy source-based distributed power generation technology is gradually challenging the traditional power system pattern, and the permeability of a micro-grid containing green new energy sources such as photovoltaic, wind power and the like in a power distribution network is higher. When the new energy power generation is accessed to the power distribution network in a large scale, the power distribution network can safely and stably run, and meanwhile, the requirement of a user on the power quality is met with great difficulty. The mutual supplement of the micro-grid mainly based on the distributed micro-source and the traditional large grid is an ideal way for fully playing the advantages of new energy and providing reliable and high-quality electric energy. Photovoltaic power generation is used as a main renewable energy source and is mainly applied to distributed grid connection at present. When the distributed photovoltaic system is connected into the power distribution network to work, the distributed photovoltaic system can break away from an external power grid support after a power grid side breaks down, and enters an off-grid mode. At the moment, the distributed photovoltaic power generation system needs to be switched from a grid-connected mode to an off-grid running state, and emergency power supply in an extreme mode is provided for a user.
In the current research, the traditional photovoltaic inverter generally adopts a current control technology in a grid-connected mode, when a large power grid fails, the large power grid can be directly cut off from the power grid to enter an independent off-grid state, the grid is connected again after the fault is repaired, the multi-mode smooth switching is difficult to realize, a grid-connected static switch is lagged behind the switching of a control program and the phenomenon that a control instruction is suddenly changed before and after the switching, voltage and current distortion is easy to generate before and after the switching, and the power supply safety is endangered.
Disclosure of Invention
In view of the above, the embodiment of the invention provides a multi-mode seamless switching photovoltaic inverter controller and a photovoltaic inverter system, which enable the photovoltaic inverter to realize smooth switching among multiple control modes.
In order to achieve the above purpose, the invention adopts the following technical scheme:
in a first aspect, an embodiment of the present invention provides a controller for a multi-mode seamless switching photovoltaic inverter, including: the controller is used for controlling the photovoltaic inverter to operate and controlling the photovoltaic inverter to switch working modes, and the working modes of the photovoltaic inverter comprise a grid-connected mode and a grid-off mode; when the grid-connected mode is switched to the off-grid mode, the controller locks the phase detected during off-grid, generates a continuously-changed phase, and sends a current instruction of the grid-connected mode to a voltage outer loop PI regulator of the off-grid mode; when the off-grid mode is switched to the grid-connected mode, the controller controls the phase output of the photovoltaic inverter to continuously change before and after switching.
Based on the first aspect, in some embodiments, the controller includes an operation control module for controlling the photovoltaic inverter to operate and a switching control module for controlling the photovoltaic inverter to switch operating modes; the switching control module comprises a power grid instantaneous phase detection module, a phase presynchronization module and a reference phase generation module, wherein the power grid instantaneous phase detection module is used for detecting the power grid phase in real time, the reference phase generation module is used for generating a continuously-changed phase when the grid-connected mode is switched to the off-grid mode, and the phase presynchronization module is used for controlling the continuous change of the phase output before and after the switching of the photovoltaic inverter when the off-grid mode is switched to the grid-connected mode.
Based on the first aspect, in some embodiments, the photovoltaic inverter includes a front-stage Boost converter, a back-stage inverter, and a filter; the operation control module is specifically used for controlling the capacitor voltage to be constant through the front-stage Boost converter, and the process is as follows: obtaining capacitance voltage u output by Boost converter dc The method comprises the steps of carrying out a first treatment on the surface of the Calculating the capacitance voltage u dc And a preset DC capacitor voltage reference value u dcref Is a first difference of (2); PI regulation is carried out on the first difference value to generate a modulation wave, and a PI regulation formula is as follows:
wherein u is dc_pwm Modulating the signal k for a Boost switch tube p_dc The value k of the proportional controller of the PI regulator i_dc Integrating the value of the controller for the PI regulator, u dcref As the reference value of the capacitor voltage at the direct current side, u dc For the dc side capacitor voltage, the PWM waveform modulates the switching duty cycle in the Boost circuit.
Based on the first aspect, in some embodiments, the photovoltaic inverter includes a front-stage Boost converter, a back-stage inverter, and a filter; the operation control module is specifically used for controlling the rear-stage inverter to output constant power, and the process is as follows: performing abc/dq conversion on the bus voltage and current of the system to obtain a voltage component and a current component under a dq coordinate system; calculating a current reference signal from the voltage component; calculating a second difference between the current reference signal and the current component, and generating a voltage modulation signal according to the second difference; and performing dq/abc conversion on the voltage modulation signal.
Based on the first aspect, in some embodiments, the abc/dq transformation expression is:
wherein i is a 、i b 、i c Respectively the values of the output current of the inverter under the abc three-phase static coordinate system, i d 、i q For the value of the inverter output current in the dq synchronous rotation coordinate system, u a 、u b 、u c Values of inverter output voltage under abc three-phase stationary coordinate system, u d 、u q For the value of the inverter output voltage in the dq synchronous rotation coordinate system, θ 1 Is the included angle between the d axis and the phase reference axis; the dq/abc transform is an inverse transform of the abc/dq transform, expressed as:
based on the first aspect, in some embodiments, in the grid-connected mode, a calculation formula of the current reference signal is:
the current reference signal comprises a current active component reference value and a current reactive component reference value, wherein i is d_ref And i q_ref Respectively a current active component reference value and a current reactive component reference value, P ref For the active power command value, Q ref For reactive power command value u d And u is equal to q The output voltage is respectively an active component and a reactive component; in the off-grid mode, the calculation formula of the current reference signal is as follows:
wherein i is d_ref And i q_ref Respectively an active component reference value and a reactive component reference value, k of the output current of the inverter p_du Proportional controller value, k for PI regulator of active component of inverter output voltage i_du Integrating the value, k, of the controller for the PI regulator of the active component of the output voltage of the inverter p_qu Is an inverterOutput voltage reactive component PI regulator proportional controller value, k i_qu Integrating the value of the controller, u, for the PI regulator of the reactive component of the output voltage of the inverter d_ref For the reference value of the active component of the output voltage of the inverter, u dc For the active component of the output voltage of the inverter, u q_ref For the reactive component reference value of the output voltage of the inverter, u q And outputting a voltage reactive component for the inverter.
Based on the first aspect, in some embodiments, the calculating a second difference of the current reference signal and the current component, generating a voltage modulation signal from the second difference comprises: calculating a current reference signal i d_ref And i q_ref And i d 、i q Generates a voltage modulation signal m by a PI regulator d And m q Voltage modulation signal m d And m q The calculation formula of (2) is as follows:
wherein m is d 、m q Respectively the d-axis modulation quantity of the output voltage of the inverter and the q-axis modulation quantity of the output voltage of the inverter,
k p_di proportional controller value, k for PI regulator of active component of inverter output current i_di Integrating the value, k, of the controller for the PI regulator of the active component of the output current of the inverter p_qi Proportional controller value, k, for the PI regulator of the reactive component of the output current of the inverter i_qi Integrating the value of the controller, i, for the PI regulator of the reactive component of the output current of the inverter d_ref For outputting the reference value, i, of the active component of the current for the inverter d Output current active component for inverter, i q_ref Output current reactive component reference value for inverter, i q And outputting a current reactive component to the inverter.
Based on the first aspect, in some embodiments, the grid instantaneous phase detection module is specifically configured to: real-time detection of three-phase voltage u of power grid ga 、u gb And u gc And performing abc/dq conversion to obtain a q-axis voltage component u q The method comprises the steps of carrying out a first treatment on the surface of the Calculating the voltage component u q A third difference value from a preset reference value; PI adjusting the third difference value to obtain the instantaneous angular frequency omega of the power grid voltage g The method comprises the steps of carrying out a first treatment on the surface of the For the angular frequency omega g Integrating to obtain the instantaneous phase theta of the power grid g The method comprises the steps of carrying out a first treatment on the surface of the Wherein the angular frequency omega g The calculation formula of (2) is as follows:
wherein omega is g For the angular frequency, k, of the grid voltage p The value k of the proportional element of the PI regulator i For the value of the PI regulator integration element, u q For the q-axis component, ω of the grid voltage 0 Is the initial frequency.
Based on the first aspect, in some embodiments, the phase pre-synchronization module is specifically configured to: obtaining the grid phase theta g Phase theta with micro-net inv A phase difference Δθ therebetween; PI regulation is carried out on the phase difference delta theta to obtain a frequency compensation signal delta f; calculating the frequency compensation signal delta f and the rated frequency f in the off-grid mode ref A fourth difference of (2); determining a frequency reference value f of the inverter according to the fourth difference value, wherein the calculation formula is as follows:
wherein f is the output frequency of the inverter, f ref For the grid frequency, f is the frequency compensation signal, k p The value k of the proportional controller of the PI regulator i Integrating the value of the controller, θ, for the PI regulator g For the phase of the grid voltage, θ inv The voltage phase is output for the inverter.
In a second aspect, an embodiment of the present invention provides a multi-mode seamless switching photovoltaic inverter system, including a photovoltaic inverter and a controller of the photovoltaic inverter as described in the first aspect above.
In the embodiment of the invention, the controller of the multi-mode seamless switching photovoltaic inverter can not only meet the power requirement of a load during grid-connected operation and off-grid operation and maintain the stability of the voltage and frequency of a power grid, but also realize the seamless smooth switching of the parallel-to-off grid mode, and the phase of the power grid is detected in real time during the parallel-to-off grid switching, and the phase pre-synchronization module and the reference phase generating module ensure the seamless switching of the inverter so as to avoid the generation of impulse voltage and current.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of a multi-mode seamless switching photovoltaic inverter system according to an embodiment of the present invention;
fig. 2 is a grid-connected mode control block diagram of a photovoltaic inverter system according to an embodiment of the present invention;
fig. 3 is a control block diagram of an off-grid mode of a photovoltaic inverter system according to an embodiment of the present invention;
fig. 4 is a micro-grid structure diagram of off-grid switching provided by an embodiment of the present invention;
fig. 5 is a control block diagram of a power grid instantaneous phase detection module according to an embodiment of the present invention;
FIG. 6 is a control block diagram of a phase presynchronization module according to an embodiment of the present invention;
FIG. 7 is a control block diagram of a reference phase generating module according to an embodiment of the present invention;
fig. 8 is a waveform diagram of capacitor voltage at a direct current side of a photovoltaic inverter according to an embodiment of the present invention, which is simulated by switching from an off-grid mode to a grid-connected mode;
fig. 9 is a waveform diagram of output voltage of a photovoltaic inverter simulated by switching the photovoltaic inverter from an off-grid mode to a grid-connected mode according to an embodiment of the present invention;
fig. 10 is a waveform diagram of output current of a photovoltaic inverter simulated by switching the photovoltaic inverter from an off-grid mode to a grid-connected mode according to an embodiment of the present invention;
fig. 11 is a waveform diagram of output power of a photovoltaic inverter simulated by switching the photovoltaic inverter from an off-grid mode to a grid-connected mode according to an embodiment of the present invention;
fig. 12 is a waveform diagram of a dc-side capacitor voltage of a photovoltaic inverter according to an embodiment of the present invention, which is a simulation of switching from a grid-connected mode to an off-grid mode;
fig. 13 is a waveform diagram of output voltage of a photovoltaic inverter in which the photovoltaic inverter provided by the embodiment of the invention is switched from a grid-connected mode to an off-grid mode;
fig. 14 is a waveform diagram of output current of a photovoltaic inverter according to an embodiment of the present invention, which is a simulation of switching the photovoltaic inverter from a grid-connected mode to an off-grid mode;
fig. 15 is a waveform diagram of output power of a photovoltaic inverter according to an embodiment of the present invention, which is a simulation of switching the photovoltaic inverter from a grid-connected mode to an off-grid mode;
fig. 16 is a schematic diagram of a terminal device according to an embodiment of the present invention.
Detailed Description
The present invention will be more clearly described with reference to the following examples. The following examples will assist those skilled in the art in further understanding the function of the present invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present invention.
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the following description will be made by way of specific embodiments with reference to the accompanying drawings.
The photovoltaic inverter adopts current type control under a grid-connected mode to output constant power; and voltage type control is adopted in the off-grid mode, so that the voltage frequency stability of the power grid is maintained. Aiming at the problem that the traditional photovoltaic inverter is easy to generate current and voltage waveform distortion when in off-grid operation mode switching, the photovoltaic inverter system with multi-mode seamless switching is provided.
The multi-mode seamless switching photovoltaic inverter system provided by the invention is shown in figure 1, and comprises a photovoltaic inverter and a controller of the photovoltaic inverter. The photovoltaic array is connected with the photovoltaic inverter, the photovoltaic inverter is connected with the power grid and the load, and the photovoltaic inverter consists of a front-stage Boost converter, a rear-stage inverter and an LC filter. The photovoltaic array is electrically connected with the front-stage Boost converter, the front-stage Boost converter is electrically connected with the rear-stage inverter, the rear-stage inverter is electrically connected with the LC filter, the LC filter is connected with the load after being connected with the switch S in series, and the power grid is connected with the load in parallel.
The controller of the photovoltaic inverter comprises an operation control module and a switching control module; the operation control module is used for controlling the operation of the photovoltaic inverter, and the switching control module is used for controlling the photovoltaic inverter to switch the working modes, wherein the working modes of the photovoltaic inverter comprise a grid-connected mode and an off-grid mode; the switching control module comprises a power grid instantaneous phase detection module, a phase presynchronization module and a reference phase generation module; the power grid instantaneous phase detection module is used for detecting the power grid phase in real time; when the grid-connected mode is switched to the off-grid mode, locking the phase detected during off-grid, wherein the reference phase generating module is used for generating continuous phase change and sending a current instruction of the grid-connected mode to the voltage outer loop PI regulator of the off-grid mode; when the off-grid mode is switched to the grid-connected mode, the phase output change of the photovoltaic inverter before and after switching is continuous through the phase pre-synchronization module.
The grid-connected mode control block diagram of the photovoltaic inverter system provided by the invention is shown as 2, and the operation process of the grid-connected mode comprises steps 101 to 102.
Step 101: the operation control module controls the capacitor voltage to be constant through the front-stage Boost converter.
Obtaining output capacitance voltage u of Boost converter dc With a given DC capacitor voltage reference u dcref Comparing the difference, and performing PI adjustment on the generated difference to generate a modulation wave, wherein the calculation formula is as follows:
in the middle of，u dc_pwm Modulating the signal k for a Boost switch tube p_dc The value k of the proportional controller of the PI regulator i_dc Integrating the value of the controller for the PI regulator, u dcref As the reference value of the capacitor voltage at the direct current side, u dc For the dc side capacitor voltage, the PWM waveform modulates the switching duty cycle in the Boost circuit.
Step 102: the operation control module controls the back-stage inverter so that the photovoltaic inverter outputs constant power.
Step 1021: and carrying out abc/dq conversion on the system bus voltage and current to obtain a voltage component and a current component under a dq coordinate system.
The system bus voltage u abc Obtaining the component u under the dq coordinate system after abc/dq transformation d 、u q System bus current i abc Obtaining component i under dq coordinate system after abc/dq conversion d 、i q . The formula of abc/dq transformation is:
wherein i is a 、i b 、i c Respectively the values of the output current of the inverter under the abc three-phase static coordinate system, i d 、i q For the value of the inverter output current in the dq synchronous rotation coordinate system, u a 、u b 、u c Values of inverter output voltage under abc three-phase stationary coordinate system, u d 、u q Value θ for inverter output voltage in dq synchronous rotation coordinate system 1 Is the angle between the d axis and the phase reference axis.
Step 1022: a current reference signal is calculated from the voltage component.
The current reference signal is calculated as follows:
wherein i is d_ref And i q_ref Respectively have currentA power component reference value and a current reactive component reference value, P ref For the active power command value, Q ref For reactive power command value u d And u is equal to q The active and reactive components of the output voltage, respectively.
Step 1023: the current reference signal and the current component are differenced to produce a voltage modulated signal.
The current reference signal i to be generated d_ref And i q_ref And i d 、i q After comparison and difference, the difference value is controlled by a PI regulator to generate a voltage modulation signal m d 、m q The calculation formula is as follows:
wherein m is d 、m q Respectively the d-axis modulation quantity and the q-axis modulation quantity, k of the output voltage of the inverter p_di Proportional controller value, k for PI regulator of active component of inverter output current i_di Integrating the value, k, of the controller for the PI regulator of the active component of the output current of the inverter p_qi Proportional controller value, k, for the PI regulator of the reactive component of the output current of the inverter i_qi Integrating the value of the controller, i, for the PI regulator of the reactive component of the output current of the inverter d_ref For outputting the reference value, i, of the active component of the current for the inverter d Output current active component for inverter, i q_ref Output current reactive component reference value for inverter, i q And outputting a current reactive component to the inverter.
Step 1024: the voltage modulated signal is subjected to dq/abc conversion.
Voltage modulation signal m d 、m q The modulation signal of the rear-stage inverter is obtained through a dq/abc conversion module, and the calculation formula of the dq/abc conversion module is as follows:
wherein i is a 、i b 、i c Respectively the values of the output current of the inverter under the abc three-phase static coordinate system, i d 、i q For the value of the inverter output current in the dq synchronous rotation coordinate system, u a 、u b 、u c Values of inverter output voltage under abc three-phase stationary coordinate system, u d 、u q Value θ for inverter output voltage in dq synchronous rotation coordinate system 1 Is the angle between the d axis and the phase reference axis.
The off-grid mode control block diagram of the photovoltaic inverter system provided by the invention is shown as 3, and comprises the following steps 201 to 202:
step 201: the operation control module controls the constant voltage of the capacitor through the front-stage Boost converter to realize the power balance between the source and the load.
Obtaining output capacitance voltage u of Boost converter dc With a given DC capacitor voltage reference u dcref Comparing the difference, and performing PI adjustment on the generated difference to generate a modulation wave, wherein the calculation formula is as follows:
wherein u is dc_pwm Modulating the signal k for a Boost switch tube p_dc The value k of the proportional controller of the PI regulator i_dc Integrating the value of the controller for the PI regulator, u dcref As the reference value of the capacitor voltage at the direct current side, u dc For the dc side capacitor voltage, the PWM waveform modulates the switching duty cycle in the Boost circuit.
Step 202: the voltage frequency support of the alternating current bus is realized by adopting V/f control through a later-stage inverter.
Step 2021: and carrying out abc/dq conversion on the system bus voltage and current to obtain a voltage component and a current component under a dq coordinate system.
The system bus voltage u abc Obtaining the component u under the dq coordinate system after abc/dq transformation d 、u q System bus current i abc Obtaining component i under dq coordinate system after abc/dq conversion d 、i q 。
Step 2022: a current reference signal is calculated from the voltage component.
Will u d 、u q With a given voltage reference U dref And U qref Comparing the difference, performing PI adjustment on the generated difference to generate a current inner loop reference signal i dref And i qref The calculation formula is as follows:
wherein i is d_ref And i q_ref Respectively an active component reference value and a reactive component reference value, k of the output current of the inverter p_du Proportional controller value, k for PI regulator of active component of inverter output voltage i_du Integrating the value, k, of the controller for the PI regulator of the active component of the output voltage of the inverter p_qu Proportional controller value, k, for output voltage reactive component PI regulator of inverter i_qu Integrating the value of the controller, u, for the PI regulator of the reactive component of the output voltage of the inverter d_ref For the reference value of the active component of the output voltage of the inverter, u dc For the active component of the output voltage of the inverter, u q_ref For the reactive component reference value of the output voltage of the inverter, u q And outputting a voltage reactive component for the inverter.
Step 2023: the current reference signal and the current component are differenced to produce a voltage modulated signal. Current reference signal i dref 、i qref Respectively with i d 、i q After comparison, the difference is input into a current inner loop, and a voltage modulation signal m is generated through PI regulation d 、m q 。
Step 2024: the voltage modulated signal is subjected to dq/abc conversion.
Voltage modulation signal m d 、m q And obtaining a modulation signal of the rear-stage inverter through the dq/abc conversion module.
The micro-grid structure diagram of the off-grid switching is shown as 4, and the phase of the output voltage of the inverter continuously changes when the mode switching is realized through the switching control module, wherein the switching control module comprises the following three parts:
1) The power grid instantaneous phase detection module;
2) A phase presynchronization module;
3) A reference phase generation module.
The control block diagram of the power grid instantaneous phase detection module is shown as 5, and comprises steps A1 to A2.
Step A1: real-time detection of three-phase voltage u of power grid ga 、u gb 、u gc And performing abc/dq conversion to obtain a q-axis voltage component u q 。
The expression is:
u q ＝Vsin(θ-θ g ) (7)
wherein u is q For the q-axis component of the voltage, the phase angle θ obtained by phase locking is expressed g And the phase angle theta of the actual grid voltage, V being the voltage amplitude, theta g For phase locking the resulting phase angle θ is the phase angle of the actual grid voltage.
Step A2: the instantaneous phase of the grid is calculated from the voltage component.
Specifically, u is q Comparing with a given reference value 0, and obtaining the tracked instantaneous angular frequency omega of the power grid voltage by the PI regulator g Diagonal frequency omega g Integrating to obtain the instantaneous phase theta of the power grid g 。
Calculating angular frequency omega g The formula of (2) is:
wherein omega is g For the angular frequency, k, of the grid voltage p The value k of the proportional element of the PI regulator i For the value of the PI regulator integration element, u q For the q-axis component, ω of the grid voltage 0 Is the initial frequency.
The phase presynchronization module control block diagram is shown in fig. 6, and includes steps B1 to B3:
step B1: obtaining the grid phase theta g Phase theta with micro-net inv Phase difference delta theta between them.
Step B2: PI regulation is carried out on the delta theta to obtain a frequency compensation signal delta f, and the frequency compensation signal delta f is matched with the rated frequency f in the off-grid mode ref The difference is made to obtain the frequency reference value of the inverter, and the calculation formula is as follows:
wherein f is the output frequency of the inverter, f ref For the grid frequency, f is the frequency compensation signal, k p The value k of the proportional controller of the PI regulator i Integrating the value of the controller, θ, for the PI regulator g For the phase of the grid voltage, θ inv The voltage phase is output for the inverter.
Step B3: the voltage frequency of the inverter is changed to approach the grid phase.
The reference phase generation module control block diagram is shown in fig. 7 and includes steps C1 to C2.
Step C1: ctrl=1 when the photovoltaic inverter is in grid-connected operation, the selector switch S is connected with the 2 channels, and theta inv ＝θ g . When the upper power supply is suddenly powered off, ctrl=0, the selector switch S is connected to the 1 channel to lock the off-grid phase, θ inv At an angular frequency of 2pi.f ref And continuing to operate.
Step C2: when the inverter is switched from off-grid mode to grid-connected operation, the phase pre-synchronization is completed before the conversion due to the existence of the phase pre-synchronization module, namely theta inv ＝θ g 。
The method for controlling the photovoltaic inverter to be smoothly switched in the off-grid mode through the switching control module is as follows, and the method comprises the steps 301 to 302.
Step 301: the photovoltaic inverter is smoothly switched from off-grid mode to grid-connected mode.
After the photovoltaic inverter is switched to a grid-connected presynchronization signal, starting a presynchronization program; the phase-locked angle of the micro-grid gradually tracks the phase of the power grid, and a grid-connected control signal Ctrl is set to be 1 after synchronization is achieved; the current inner loop command of the inverter is switched from the off-grid mode to the grid-connected mode.
Step 302: the photovoltaic inverter is smoothly switched from the grid-connected mode to the off-grid mode.
Setting a control signal Ctrl to 0, and locking the off-network phase; reference frequency tracking off-grid phase of main control inverter and inverter working angle frequency theta inv At 2 pi f ref Continuing to operate; the working value of the outer ring PI regulator of the inverter in the grid-connected mode is given to the outer ring PI regulator of the off-grid mode inverter, and the specific value is as follows:
I dq_ref_2_initial ＝I dq_ref_1_final (10)
wherein I is dq_ref_2_initial Initial output value of voltage outer loop PI regulator in off-grid mode, I dq_ref_1_final The current command value is in a grid-connected mode.
Example 1 in order to test the invention, a simulation of a photovoltaic inverter was built in MATLAB/Simulink.
The simulated waveform diagrams of the photovoltaic inverter switching from the off-grid mode to the grid-connected mode are shown in fig. 8, 11 and are respectively a direct-current side capacitor voltage waveform, a photovoltaic inverter output current waveform and a photovoltaic inverter output power waveform. It can be seen that the three-phase output voltage, the three-phase output current and the DC side capacitor voltage waveform of the photovoltaic inverter can all realize smooth transition. After the grid-connected mode operation is switched into, the internal power of the micro-grid is balanced by energy storage, and the power of the photovoltaic inverter is changed from 10kW power output to 5kW constant power output in the off-grid state.
The simulation waveform diagrams of the photovoltaic inverter switching from the grid-connected mode to the off-grid mode are shown in fig. 12, 13, 14 and 15, and are respectively a direct-current side capacitor voltage waveform, a photovoltaic inverter output current waveform and a photovoltaic inverter output power waveform. The photovoltaic is changed from grid connection to off-grid mode, the frequency and phase change of output voltage are smooth in the conversion process, and the voltage and the current are continuous and have no impact; the output power of the photovoltaic inverter is changed from constant output of 8kW when grid connected to balanced load power of 10kW when off-grid.
Fig. 16 is a schematic diagram of a terminal device according to an embodiment of the present invention. As shown in fig. 16, the terminal device 4 of this embodiment includes: a processor 40, a memory 41, and a computer program 42 stored in the memory 41 and executable on said processor 40, such as a multi-mode seamless switching photovoltaic inverter controller control program.
Illustratively, the computer program 42 may be partitioned into one or more modules/units that are stored in the memory 41 and executed by the processor 40 to complete the present invention. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions for describing the execution of the computer program 42 in the terminal device 4.
The terminal device 4 may be a computing device such as a desktop computer, a notebook computer, a palm computer, a cloud server, etc. The terminal device may include, but is not limited to, a processor 40, a memory 41. It will be appreciated by those skilled in the art that fig. 16 is merely an example of the terminal device 4 and does not constitute a limitation of the terminal device 4, and may include more or less components than illustrated, or may combine certain components, or different components, e.g., the terminal device may further include an input-output device, a network access device, a bus, etc.
The processor 40 may be a central processing unit (Central Processing Unit, CPU), other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 41 may be an internal storage unit of the terminal device 4, such as a hard disk or a memory of the terminal device 4. The memory 41 may be an external storage device of the terminal device 4, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card) or the like, which are provided on the terminal device 4. Further, the memory 41 may also include both an internal storage unit and an external storage device of the terminal device 4. The memory 41 is used for storing the computer program as well as other programs and data required by the terminal device. The memory 41 may also be used for temporarily storing data that has been output or is to be output.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions. The functional units and modules in the embodiment may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit, where the integrated units may be implemented in a form of hardware or a form of a software functional unit. In addition, the specific names of the functional units and modules are only for distinguishing from each other, and are not used for limiting the protection scope of the present invention. The specific working process of the units and modules in the above system may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus/terminal device and method may be implemented in other manners. For example, the apparatus/terminal device embodiments described above are merely illustrative, e.g., the division of the modules or units is merely a logical function division, and there may be additional divisions in actual implementation, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in the embodiments of the present invention may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
The integrated modules/units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the present invention may implement all or part of the flow of the method of the above embodiment, or may be implemented by a computer program to instruct related hardware, where the computer program may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the computer program may implement the steps of each of the method embodiments described above. Wherein the computer program comprises computer program code which may be in source code form, object code form, executable file or some intermediate form etc. The computer readable medium may include: any entity or device capable of carrying the 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. It should be noted that the computer readable medium contains content that can be appropriately scaled according to the requirements of jurisdictions in which such content is subject to legislation and patent practice, such as in certain jurisdictions in which such content is subject to legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunication signals.
The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention, and are intended to be included in the scope of the present invention.
Claims (7)
1. The controller is characterized by being used for controlling the photovoltaic inverter to operate and controlling the photovoltaic inverter to switch working modes, wherein the working modes of the photovoltaic inverter comprise a grid-connected mode and an off-grid mode;
when the grid-connected mode is switched to the off-grid mode, the controller locks the phase detected during off-grid, generates a continuously-changed phase, and sends a current instruction of the grid-connected mode to a voltage outer loop PI regulator of the off-grid mode;
when the off-grid mode is switched to the grid-connected mode, the controller controls the phase output of the photovoltaic inverter to continuously change before and after switching;
the controller comprises an operation control module and a switching control module, wherein the operation control module is used for controlling the photovoltaic inverter to operate, and the switching control module is used for controlling the photovoltaic inverter to switch working modes;
the switching control module comprises a power grid instantaneous phase detection module, a phase presynchronization module and a reference phase generation module, wherein the power grid instantaneous phase detection module is used for detecting the power grid phase in real time, the reference phase generation module is used for generating a continuously-changed phase when the grid-connected mode is switched to the off-grid mode, and the phase presynchronization module is used for controlling the continuous change of the phase output before and after the switching of the photovoltaic inverter when the off-grid mode is switched to the grid-connected mode;
the power grid instantaneous phase detection module is specifically used for:
real-time detection of three-phase voltage of power gridu ga 、u gb Andu gc and performing abc/dq transformation to obtainqVoltage component of shaftu q ；
Calculating the voltage componentu q A third difference value from a preset reference value;
PI adjusting is carried out on the third difference value to obtain the instantaneous angular frequency of the power grid voltageω g ；
For the angular frequencyω g Integrating to obtain instantaneous phase of power gridθ g ；
Wherein the angular frequencyω g The calculation formula of (2) is as follows:
in the method, in the process of the invention,ω g for the angular frequency of the voltage of the power grid,k p is the value of the proportional element of the PI regulator,k i for the value of the PI regulator integration element,u q for mains voltageqAn axis component of the optical fiber,ω 0 for the initial frequencyA rate;
the phase pre-synchronization module is specifically configured to:
obtaining grid phaseθ g Phase with micro-gridθ inv Phase difference betweenΔθ；
For phase differenceΔθPI regulation is carried out to obtain a frequency compensation signalΔf；
Calculating a frequency compensation signalΔfWith the rated frequency in the off-grid modef ref A fourth difference of (2);
determining a frequency reference value of the inverter according to the fourth difference valueThe calculation formula is as follows:
in the method, in the process of the invention,ffor the output frequency of the inverter,f ref for the frequency of the power grid,ffor the frequency compensation signal,k p is the value of the proportional controller of the PI regulator,k i integrating the value of the controller for the PI regulator,for mains voltage phase>The voltage phase is output for the inverter.
2. The controller for a multi-mode seamless switching photovoltaic inverter of claim 1, wherein the photovoltaic inverter comprises a front-stage Boost converter, a back-stage inverter, and a filter;
the operation control module is specifically used for controlling the capacitor voltage to be constant through the pre-stage Boost converter, and the process is as follows:
obtaining capacitance voltage output by Boost converter；
Calculating capacitance voltageAnd a preset DC capacitor voltage reference value +.>Is a first difference of (2);
PI regulation is carried out on the first difference value to generate a modulation wave, and a PI regulation formula is as follows:
in the method, in the process of the invention,modulating a signal for a Boost switching tube, +.>For the value of the proportional controller of the PI regulator, < >>Integrating the value of the controller for the PI regulator, +.>Is the reference value of the capacitor voltage at the DC side, < >>For the dc side capacitor voltage, the PWM waveform modulates the switching duty cycle in the Boost circuit.
3. The controller for a multi-mode seamless switching photovoltaic inverter of claim 1, wherein the photovoltaic inverter comprises a front-stage Boost converter, a back-stage inverter, and a filter;
the operation control module is specifically used for controlling the rear-stage inverter to output constant power, and the process is as follows:
performing abc/dq conversion on the bus voltage and current of the system to obtain a voltage component and a current component under a dq coordinate system;
calculating a current reference signal from the voltage component;
calculating a second difference between the current reference signal and the current component, and generating a voltage modulation signal according to the second difference;
and performing dq/abc conversion on the voltage modulation signal.
4. The controller for a multi-modal, seamless switched photovoltaic inverter of claim 3, wherein the abc/dq transformation expression is:
in the method, in the process of the invention,i a 、i b 、i c the values of the inverter output currents in the abc three-phase stationary coordinate system are respectively,i d 、i q for the value of the inverter output current in the dq synchronous rotation coordinate system,u a 、u b 、u c respectively the values of the inverter output voltages in an abc three-phase static coordinate system,u d 、u q for the value of the inverter output voltage in the dq synchronous rotation coordinate system,θ 1 is the included angle between the d axis and the phase reference axis;
the dq/abc transform is an inverse transform of the abc/dq transform, expressed as:
。
5. the controller for a multi-mode seamless switching photovoltaic inverter of claim 3, wherein in the grid-tie mode, the current reference signal is calculated as:
the current reference signal comprises a current active component reference value and a current reactive component reference value, whereini d_ref And (3) withi q_ref The reference value of the current active component and the reference value of the current reactive component are respectively,P ref in order to be an active power command value,Q ref is a reactive power command value, and the reactive power command value,u d and (3) withu q The output voltage is respectively an active component and a reactive component;
in the off-grid mode, the calculation formula of the current reference signal is as follows:
in the method, in the process of the invention,i d_ref and (3) withi q_ref Respectively outputting an active component reference value and a reactive component reference value of the current output by the inverter,k p_du for the value of the inverter output voltage active component PI regulator proportional controller,k i_du integrating the value of the controller for the active component PI regulator of the inverter output voltage,k p_qu for the value of the inverter output voltage reactive component PI regulator proportional controller,k i_qu integrating the value of the controller for the inverter output voltage reactive component PI regulator,u d_ref for the inverter output voltage active component reference value,u dc for the active component of the output voltage of the inverter,u q_ref for the inverter output voltage reactive component reference value,u q and outputting a voltage reactive component for the inverter.
6. The controller for a multi-mode seamless switching photovoltaic inverter of claim 3, wherein the calculating a second difference between the current reference signal and the current component, generating a voltage modulation signal based on the second difference, comprises:
calculating the currentReference signali d_ref And (3) withi q_ref And (3) withi d 、i q Generates a voltage modulation signal by the second difference value through a PI regulatorm d Andm q voltage modulated signalm d Andm q the calculation formula of (2) is as follows:
in the method, in the process of the invention,m d 、m q respectively the d-axis modulation quantity of the output voltage of the inverter and the q-axis modulation quantity of the output voltage of the inverter,k p_di for the value of the inverter output current active component PI regulator proportional controller,k i_di integrating the value of the controller for the PI regulator of the active component of the inverter output current,k p_qi for the value of the inverter output current reactive component PI regulator proportional controller,k i_qi integrating the value of the controller for the inverter output current reactive component PI regulator,i d_ref for the inverter output current active component reference value,i d for the inverter to output a current active component,i q_ref for the inverter output current reactive component reference value,i q and outputting a current reactive component to the inverter.
7. A multi-mode seamless switching photovoltaic inverter system comprising a photovoltaic inverter and a controller of the multi-mode seamless switching photovoltaic inverter of any of claims 1-6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110902897.7A CN113725894B (en) | 2021-08-06 | 2021-08-06 | Multi-mode seamless switching photovoltaic inverter controller and photovoltaic inverter system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110902897.7A CN113725894B (en) | 2021-08-06 | 2021-08-06 | Multi-mode seamless switching photovoltaic inverter controller and photovoltaic inverter system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113725894A CN113725894A (en) | 2021-11-30 |
| CN113725894B true CN113725894B (en) | 2023-08-25 |
Family
ID=78675090
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110902897.7A Active CN113725894B (en) | 2021-08-06 | 2021-08-06 | Multi-mode seamless switching photovoltaic inverter controller and photovoltaic inverter system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113725894B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170123021A (en) * | 2016-04-28 | 2017-11-07 | (주) 이이시스 | Distributed generating micro-grid system and static transfer switching method thereof |
| KR101837742B1 (en) * | 2017-08-14 | 2018-03-13 | 주식회사 에너지파트너즈 | Grid-connected inverter system with seamless transfer function |
| CN109888829A (en) * | 2019-03-21 | 2019-06-14 | 哈尔滨工业大学 | Photovoltaic microgrid system based on the sagging control of improvement perception is from grid-connected seamless switch-over system |
| CN110277793A (en) * | 2018-03-16 | 2019-09-24 | 特变电工新疆新能源股份有限公司 | A kind of two-stage type photovoltaic DC-to-AC converter active power balance control method |
| CN112366744A (en) * | 2020-08-14 | 2021-02-12 | 中国电力科学研究院有限公司 | Inverter seamless switching control method and device |
-
2021
- 2021-08-06 CN CN202110902897.7A patent/CN113725894B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170123021A (en) * | 2016-04-28 | 2017-11-07 | (주) 이이시스 | Distributed generating micro-grid system and static transfer switching method thereof |
| KR101837742B1 (en) * | 2017-08-14 | 2018-03-13 | 주식회사 에너지파트너즈 | Grid-connected inverter system with seamless transfer function |
| CN110277793A (en) * | 2018-03-16 | 2019-09-24 | 特变电工新疆新能源股份有限公司 | A kind of two-stage type photovoltaic DC-to-AC converter active power balance control method |
| CN109888829A (en) * | 2019-03-21 | 2019-06-14 | 哈尔滨工业大学 | Photovoltaic microgrid system based on the sagging control of improvement perception is from grid-connected seamless switch-over system |
| CN112366744A (en) * | 2020-08-14 | 2021-02-12 | 中国电力科学研究院有限公司 | Inverter seamless switching control method and device |
Non-Patent Citations (1)
| Title |
|---|
| 光伏发电并/离网切换控制策略研究;万晓凤;胡伟;余运俊;辛建波;;电测与仪表(第11期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113725894A (en) | 2021-11-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Li et al. | New decentralized control scheme for a dynamic voltage restorer based on the elliptical trajectory compensation | |
| JP5585371B2 (en) | Distributed power system | |
| Fang et al. | A novel frequency-adaptive PLL for single-phase grid-connected converters | |
| CN107394818B (en) | Energy storage battery grid-connected operation control method and device based on energy storage converter | |
| JP2012205325A (en) | Distributed power supply system | |
| Jenisha et al. | Power electronic interface with de‐coupled control for wind‐driven PMSG feeding utility grid and DC load | |
| Vittorias et al. | A bidirectional battery charger for electric vehicles with V2G and V2H capability and active and reactive power control | |
| CN113991730A (en) | Control mode switching method and system for current source and voltage source of grid-connected inverter | |
| CN110943468A (en) | Control method, device and system of dual-mode energy storage converter | |
| CN112186804A (en) | Method and system for bus voltage unbalance and harmonic compensation of island microgrid | |
| Prabaharan et al. | An overview of control techniques and technical challenge for inverters in micro grid | |
| Jabbarnejad et al. | Sensorless virtual flux combined control of grid connected converters with high power quality under unbalanced grid operation | |
| Baharizadeh et al. | Control method for improvement of power quality in single interlinking converter hybrid AC‐DC microgrids | |
| JP5498100B2 (en) | Inverter control circuit, grid-connected inverter system equipped with this inverter control circuit | |
| Kalaivani et al. | Grid Integration of Three-phase Inverter using Decoupled Double Synchronus Reference Frame PLL | |
| CN113725894B (en) | Multi-mode seamless switching photovoltaic inverter controller and photovoltaic inverter system | |
| Gupta et al. | AES-FLL control of RES powered microgrid for power quality improvement with synchronization control | |
| CN102623996B (en) | Active power filter closed loop control method based on decoupling resonance regulator array | |
| JP2012231606A (en) | System interconnection power conversion device | |
| KR101545139B1 (en) | Method of phase tracking of power system using LPN filter | |
| CN114744685A (en) | Adaptive power sharing control strategy for multi-voltage-level micro-grid | |
| CN112865188B (en) | Plug-and-play battery energy storage power station flexible access and exit method | |
| Fereidouni et al. | A new space-vector Hysteresis current-control modulation for active power filter applications | |
| KR102381735B1 (en) | Grid connected three-phase inverter control apparatus | |
| KR101732028B1 (en) | Wind power generator and method for controlling a compensation of unbalance voltage in linking point of system |
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 |