CN110336319A - A kind of control method of the grid-connected photovoltaic system sagging based on power - Google Patents
A kind of control method of the grid-connected photovoltaic system sagging based on power Download PDFInfo
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- 238000007665 sagging Methods 0.000 title abstract 3
- 238000010248 power generation Methods 0.000 claims description 30
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Classifications
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- H02J3/383—
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/48—Controlling the sharing of the in-phase component
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- 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
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- 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
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- 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
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- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention discloses a kind of control methods of grid-connected photovoltaic system sagging based on power, are used for two-stage type grid-connected system, comprising the following steps: 1) control of prime Boost: the prime Boost uses the control mode of two close cycles；2) control of latter stage grid inverter: the latter stage grid inverter simulates the control mode of RSG primary frequency modulation using the sagging control of function frequency.The present invention can be realized guarantee system in the case where source side or load side fluctuate, and system still maintains normal operation.
Description
Technical Field
The invention belongs to a control method of a photovoltaic grid-connected power generation system, and particularly relates to a control method of a two-stage grid-connected power generation system.
Background
In a classic two-stage grid-connected power generation system, the two-stage grid-connected power generation system comprises a front stage Boost and a rear stage grid-connected inverter, and the control modes of the two-stage grid-connected inverter are consistent, so that the system is easy to fluctuate on a power supply side or a load side during operation, and the operation of the system is influenced. The power supply side has the influence on the fluctuation of input power such as illumination intensity and temperature; the load side is such as: heavy duty switching can produce large power fluctuations, etc.
In the prior art, a general photovoltaic grid-connected power generation system only generates power according to the maximum power and does not participate in the frequency response event of the system; and then under the condition of not increasing peripheral equipment, the grid-connected inverter can not participate in power grid frequency modulation, and meanwhile, the system runs slowly due to external disturbance.
Disclosure of Invention
In order to overcome the technical problems and ensure that the system still keeps normal operation and the direct current bus voltage is stable under the condition that the system fluctuates at the power supply side or the load side, the invention provides a control method of a power droop-based photovoltaic grid-connected power generation system, which adopts different control modes at the front stage and the rear stage respectively.
In order to achieve the technical effects, the invention is realized by the following technical scheme.
A control method of a photovoltaic grid-connected power generation system based on power droop is used for a two-stage grid-connected power generation system and comprises the following steps:
1) control of the preceding stage Boost converter: the preceding stage Boost converter adopts a double closed loop control mode;
2) controlling a rear-stage grid-connected inverter: the later stage grid-connected inverter adopts a control mode of simulating RSG primary frequency modulation by power frequency droop control.
Further, the control of the preceding stage Boost converter in step 1) is specifically as follows: the preceding stage Boost adopts a voltage and current double closed loop control mode. By the control mode of the voltage and current double closed loop, the voltage of the direct current bus can be maintained to be stable, so that constant power can be injected into the system, and constant output of the grid-connected power generation system is realized; and the whole output is stable, and the fluctuation is not easy to occur on the power supply side and the load side.
Further, the voltage and current double closed loop control method specifically includes: a double closed-loop control mode of a direct-current voltage outer loop and a current inner loop is adopted. By the control mode, the direct-current voltage outer ring is responsible for maintaining the voltage of the direct-current bus to be constant and outputting the current instruction of the photovoltaic module, and the current inner ring is used for accelerating the response speed of the system and limiting the output current of the photovoltaic module.
Further, the bandwidth of the current inner ring is 5-10 times of the bandwidth of the direct-current voltage outer ring. By means of the relatively wide inner loop of the current,
further, in the control of the later stage grid-connected inverter, when the influence of reactive power is not considered, the later stage grid-connected inverter is controlled by adopting a current inner loop. By not considering the control outer ring of the reactive power but only considering the reactive current inner ring, the control structure is simplified, and meanwhile, the control efficiency is improved. A normal inverter or synchronous machine comprises two control loops, active and reactive. Because the influence of reactive power is not considered, only the current inner loop is adopted for control. And for an active control loop, active frequency control is adopted, and the frequency dynamic of the power grid is responded.
Further, the control of the post-stage grid-connected inverter in the step 2) is specifically as follows: for the active part of the inverter, the control mode of simulating the RSG primary frequency modulation process by using frequency droop control is firstly utilized for controlling, and then the output power output by the frequency droop control is superposed on the active given power to form the output of the active power of the later stage grid-connected inverter. Through the control, the output of the active power of the system is responded, and the output of the power control loop is used as the given value of the inductive current inner loop, so that the current inner loop accelerates the response speed of the system and accelerates the control speed.
Further, the control of the post-stage grid-connected inverter in the step 2) is specifically controlled by a formula (1):
in the formula (1), PωIn response to the amount of power change of the interference, DpFor frequency droop control coefficients, omega0Is the nominal angular frequency, omega, of the systemgIs the actual angular frequency of the grid. By means of this formula, it can be seen that,and the control of the grid-connected inverter is realized only by depending on the power variation of response interference and the actual angular frequency of the power grid, so that the adjustment parameters are few, and the control speed is high.
Further, in the step 2) of controlling the later stage grid-connected inverter, the current limiting for the output current of the grid-connected inverter is also included. And the current is limited, so that the safe operation of the inverter can be ensured.
Further, the current limiting also includes controlling the output current according to the formula (2):
wherein: kpIs the proportionality coefficient of the power loop, KiIs an integral coefficient of the power loop, P0Setting power, P, for a subsequent stage grid-connected invertereElectromagnetic power detected in real time.
In particular, the active current I of the injection systemdSet power P by the system0And coupling P to the grid frequencyωThe photovoltaic power generation system consists of two parts, the limit of constant traditional output power is overcome, and the output power of the photovoltaic system is changed. Coupled with the frequency of the power grid, the system responds to the dynamic state of the frequency of the power grid and actively assumes the responsibility of source load unbalance.
The invention has the following beneficial effects:
in the invention, the preceding stage Boost converter adopts a control strategy of a direct current bus voltage outer ring and a photovoltaic current inner ring, and the photovoltaic module and the preceding stage Boost converter can be similar to one direct current source in a steady state; in order to respond to the dynamic frequency modulation process of the power grid, the later stage grid-connected inverter adopts a control strategy of a power frequency outer ring and an inductive current inner ring to ensure that the system stably operates under the action of interference. Under the condition that no peripheral equipment is added, the photovoltaic grid-connected power generation system can also realize the function of participating in power grid frequency modulation.
In the invention, in order to ensure that the system still keeps normal operation under the condition that the system fluctuates at the power supply side or the load side, the dynamic response can be carried out only through the later stage grid-connected inverter, and the external disturbance is inhibited. The rear-stage grid-connected inverter corresponds to the RSG, and the primary frequency modulation process of the RSG is simulated by adopting power frequency droop control.
Drawings
Fig. 1 is a control schematic diagram of a power droop-based photovoltaic grid-connected power generation system provided by the invention;
fig. 2 is a simplified single-phase circuit diagram according to embodiment 1 of the present invention;
FIG. 3 is a vector diagram in example 1 of the present invention;
fig. 4 is a control schematic diagram of a preceding stage Boost converter provided by the present invention;
fig. 5 is a control schematic diagram of the post-stage grid-connected inverter provided by the invention.
Detailed Description
The present invention will be further described with reference to the following examples.
The invention discloses a control method of a photovoltaic grid-connected power generation system based on power droop, which is used for a two-stage grid-connected power generation system and comprises the following steps:
1) control of the preceding stage Boost converter: the preceding stage Boost converter adopts a double closed loop control mode;
the method specifically comprises the following steps: the preceding stage Boost adopts a voltage and current double closed loop control mode. Through the control mode of the voltage and current double closed loop, the voltage stability of the direct current bus can be maintained, so that constant power can be injected into the system conveniently, and the constant output of the grid-connected power generation system is realized.
The control mode of the voltage and current double closed loop is specifically as follows: a double closed-loop control mode of a direct-current voltage outer loop and a current inner loop is adopted. By the control mode, the direct-current voltage outer ring is responsible for maintaining the voltage of the direct-current bus to be constant and outputting the current instruction of the photovoltaic module, and the current inner ring is used for accelerating the response speed of the system and limiting the output current of the photovoltaic module.
The bandwidth of the current inner ring is 5-10 times of that of the direct-current voltage outer ring, namely the bandwidth of the current inner ring is far larger than that of the direct-current voltage outer ring. The sampling periods are different because the time scales are different. The controller bandwidth is then at its maximum the nyquist frequency, but engineering experience is typically 1/5-1/10.
Further, in the control of the later stage grid-connected inverter, when the influence of reactive power is not considered, the later stage grid-connected inverter is controlled by adopting a current inner loop. For a normal inverter or synchronous machine, two control loops of active and reactive are included. Because the influence of reactive power is not considered, only the current inner loop is adopted for control. And for an active control loop, active frequency control is adopted, and the frequency dynamic of the power grid is responded.
2) Controlling a rear-stage grid-connected inverter: and the later stage grid-connected inverter adopts a control mode of power frequency droop control simulation RSG primary frequency modulation.
The method specifically comprises the following steps: for the active part of the inverter, the control mode of simulating the RSG primary frequency modulation process by using frequency droop control is firstly utilized for controlling, and then the output power output by the frequency droop control is superposed on the active given power to form the output of the active power of the later stage grid-connected inverter. Through the control, the output of the active power of the system is responded, and the output of the power control loop is used as the given value of the inductive current inner loop, so that the current inner loop accelerates the response speed of the system and accelerates the control speed.
Further, the control of the post-stage grid-connected inverter in the step 2) is specifically controlled by a formula (1):
in the formula (1), PωIn response to the amount of power change of the interference, DpFor frequency droop control coefficients, omega0Is the nominal angular frequency, omega, of the systemgIs the actual angular frequency of the grid. Through the formula, the control of the rear grid-connected inverter and the grid-connected inverter only needs to depend on the power variation of response interference and the actual angular frequency of a power grid for control and regulation, the adjustment parameters are few, and the control speed is high.
Further, in the step 2), the control of the post-stage grid-connected inverter further includes current limiting, where the current limiting specifically is what current is limited or what the current is. And the current is limited, so that the safe operation of the inverter can be ensured.
Further, the current limiting also includes controlling the output current according to the formula (2):
wherein: kpIs the proportionality coefficient of the power loop, KiIs an integral coefficient of the power loop, P0Setting power, P, for a subsequent stage grid-connected invertereElectromagnetic power detected in real time.
According to the formula (2), the control of the rear grid-connected inverter and the grid-connected inverter only needs to depend on the power variation of response interference and the actual angular frequency of the power grid for control and adjustment, the adjustment parameters are few, and the control speed is high.
Example 1
As shown in fig. 1, the system is a photovoltaic grid-connected power generation system based on power frequency droop control, and the system is composed of a photovoltaic module (PV in the figure), a front-stage Boost converter and a rear-stage inverter, and specifically is a Static Synchronous Generator (SSG). In this embodiment, a power supply is provided through a photovoltaic module, that is, PV, and then the power supply is transmitted to a subsequent stage grid-connected inverter through voltage and inductance, and the power supply is provided for a load and a power grid after being processed by the subsequent stage grid-connected inverter. In the embodiment, a power supply is provided through a photovoltaic module, namely PV, the power supply is boosted through a front-stage Boost converter and then transmitted to a rear-stage grid-connected inverter, and the power supply is processed by the rear-stage grid-connected inverter and then supplied to a load and a power grid. The photovoltaic component and the front stage Boost are controlled by the direct current voltage outer ring and the current inner ring, the rear stage grid-connected inverter is controlled by the power droop, and the power grid and the load fluctuation are responded.
Corresponding to RSG (namely, rolling Synchronous Generator), the PV and the front stage Boost converter in the present embodiment correspond to a prime mover, and the rear stage grid-connected inverter corresponds to a Synchronous machine.
Because a significant corresponding relation exists between the SSG and the RSG, a photovoltaic component in the SSG corresponds to the primary energy of the RSG; the front-stage Boost maintains the voltage stability of a direct-current bus by adopting a voltage and current double-closed-loop control strategy, and constant power is injected into a system and corresponds to a prime motor of the RSG; the rear-stage grid-connected inverter corresponds to the RSG, and the primary frequency modulation process of the RSG is simulated by adopting power frequency droop control.
In order to simplify the electromechanical transient process of the SSG, the grid-connected pv power generation system shown in fig. 1 can be simplified to a single-phase equivalent circuit shown in fig. 2. Wherein, UsThe outlet voltage of the rear-stage grid-connected inverter before filtering corresponds to the excitation potential amplitude of the RSG; delta is a phase angle difference between the rear-stage grid-connected inverter and the power grid, and corresponds to a power angle difference between an excitation potential and a terminal voltage of the RSG; rsAnd LsRespectively representing the equivalent resistance and the equivalent inductance of the L-shaped filter and the rear-stage inverter, and corresponding to the stator resistance and the inductance of the RSG; l isgThe equivalent impedance between the photovoltaic grid-connected power generation system and the infinite power grid is represented, and the value of the equivalent impedance represents the connection strength between the system and the infinite power grid; u shapegThe terminal voltage of the grid-connected inverter is consistent with the voltage of a power grid.
According to the circuit principle, the single-phase simplified circuit of the SSG of fig. 2 is easy to obtain:
in the formula: and I is the output current of the later stage grid-connected inverter.
Equation (1) can be expressed as:
neglecting the series equivalent resistance RsOn the premise that the single-phase simplified diagram of the system shown in fig. 2 is described by using a vector diagram (as shown in fig. 3, the vector diagram of the system is shown), a synchronous rotating coordinate system based on the grid voltage vector orientation is adopted, and a grid voltage vector U is enabled to be obtainedgCoinciding with the d-axis of the synchronous rotating coordinate system. Wherein,the phase difference between the terminal voltage of the grid-connected inverter and the output current is phi, and the phase difference between the outlet voltage of the grid-connected inverter before filtering and the output current is phi.
PeAnd QeRespectively as follows:
combining fig. 3 and equation (3), one can obtain:
in the formula: x ═ ω Ls。
As can be seen from equations (3) and (4), the active power P of the grid-connected inverter is considered to be unchanged in the system configuration parameterseMainly dependent on the power angle difference delta, and the reactive power QeBy the outlet voltage U of the invertersAnd terminal voltage UgAnd (4) jointly determining. Therefore, the power of the inverter can be independently controlled by controlling the voltage amplitude and phase, respectively.
Referring to fig. 4, a control schematic diagram of a pre-stage Boost converter in the present invention is shown, and referring to fig. 4, it can be known that, in the double closed loop control strategy of the dc voltage outer loop and the current inner loop, the bandwidth of the current inner loop is generally much larger than that of the dc voltage outer loop. When the dynamic problem of the time scale of the direct current voltage is researched, the dynamic process of the current inner loop can be ignored. Therefore, the output current of the preceding stage Boost converter satisfies the following conditions:
in the formula: kp *Is the proportionality coefficient of the outer loop of the DC voltage, Ki *As integral coefficient of outer loop of DC voltage，Udc*Is a set value of DC bus voltage, UdcThe voltage detection value is a direct current bus voltage detection value.
Under the double closed-loop control action of the direct-current voltage outer ring and the current inner ring, the preceding-stage Boost converter enters into steady-state operation, and the direct-current bus voltage UdcThe voltage of the photovoltaic module and the preceding stage Boost converter can be approximately a direct current voltage source.
Referring to fig. 5, as a control schematic diagram of the subsequent stage grid-connected inverter in the present embodiment, the frequency droop control may be expressed by a formula:
in the formula: pωIn response to the amount of power change of the interference, DpFor frequency droop control coefficients, omega0Is the nominal angular frequency, omega, of the systemgIs the actual angular frequency of the grid.
By using the idea of multi-time scale modeling, ignoring the electromagnetic time dynamic process of the current inner loop, only considering the time scale of the power control loop, the output current of the later stage grid-connected inverter shown in fig. 5 is represented as:
in the formula: kpIs the proportionality coefficient of the power loop, KiIs an integral coefficient of the power loop, P0Setting power, P, for a subsequent stage grid-connected invertereElectromagnetic power detected in real time.
In this embodiment, it may be approximated to one direct current source; in order to respond to the dynamic frequency modulation process of the power grid, the later stage grid-connected inverter adopts a control strategy of a power frequency outer ring and an inductive current inner ring to ensure that the system stably operates under the action of interference.
In the embodiment, the voltage and current double-closed-loop control strategy is adopted by the front-stage Boost to maintain the voltage stability of the direct-current bus, so that constant power is injected into the system and corresponds to a prime mover of the RSG; the direct current voltage outer ring is responsible for maintaining the voltage of the direct current bus constant and outputting a current instruction of the photovoltaic module, and the current inner ring is used for accelerating the response speed of the system and limiting the output current of the photovoltaic module.
Further, in order to ensure that the system still keeps normal operation under the condition that the system fluctuates at the power supply side or the load side, the dynamic response can be carried out only through the later stage grid-connected inverter, and the external disturbance is restrained. The rear-stage grid-connected inverter corresponds to the RSG, and the primary frequency modulation process of the RSG is simulated by adopting power frequency droop control. Under the condition of not considering the influence of reactive power on a system, only current inner loop control is adopted; in the active part, the frequency droop control is firstly utilized to simulate the primary frequency modulation process of the traditional synchronous generator, and the output P of the frequency droop ringωSuperposition to active power given P0In the above, the output of the active power of the response system, the output of the power control loop is used as the given of the inductive current inner loop, the current inner loop accelerates the response speed of the system, and the inverter is ensured to run safely by current limiting.
In this embodiment, the preceding-stage Boost converter adopts a control strategy of a direct-current bus voltage outer ring and a photovoltaic current inner ring, and the photovoltaic module and the preceding-stage Boost converter can be approximately one direct-current source in a steady state; in order to respond to the dynamic frequency modulation process of the power grid, the later stage grid-connected inverter adopts a control strategy of a power frequency outer ring and an inductive current inner ring to ensure that the system stably operates under the action of interference. The photovoltaic grid-connected power generation system can also realize the function of participating in power grid frequency modulation under the condition that peripheral equipment is not added.
The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (9)
1. A control method of a power droop-based photovoltaic grid-connected power generation system is used for a two-stage grid-connected power generation system and is characterized by comprising the following steps:
1) control of the preceding stage Boost converter: the preceding stage Boost converter adopts a double closed loop control mode;
2) controlling a rear-stage grid-connected inverter: the later stage grid-connected inverter adopts a control mode of simulating RSG primary frequency modulation by power frequency droop control.
2. The control method of the power droop-based photovoltaic grid-connected power generation system according to claim 1, wherein the control of the pre-stage Boost converter in the step 1) is specifically as follows: the preceding stage Boost adopts a voltage and current double closed loop control mode.
3. The control method of the power droop-based photovoltaic grid-connected power generation system according to claim 2, wherein the voltage and current double closed loop control mode is specifically as follows: a double closed-loop control mode of a direct-current voltage outer loop and a current inner loop is adopted.
4. The control method of the power droop-based photovoltaic grid-connected power generation system according to claim 3, wherein the current inner loop bandwidth is 5-10 times the direct-current voltage outer loop bandwidth.
5. The power droop-based photovoltaic grid-connected power generation system according to claim 1, wherein in the control of the later-stage grid-connected inverter, when the influence of reactive power is not considered, the later-stage grid-connected inverter is controlled by using a current inner loop.
6. The power droop-based photovoltaic grid-connected power generation system according to claim 1, wherein the control of the subsequent grid-connected inverter in the step 2) is specifically: for the active part of the inverter, the control mode of simulating the RSG primary frequency modulation process by using frequency droop control is firstly utilized for controlling, and then the output power output by the frequency droop control is superposed on the active given power to form the output of the active power of the later stage grid-connected inverter.
7. The power droop-based photovoltaic grid-connected power generation system according to claim 1, wherein the control of the subsequent grid-connected inverter in the step 2) is specifically controlled by a formula (1):
in the formula (1), PωIn response to the amount of power change of the interference, DpFor frequency droop control coefficients, omega0Is the nominal angular frequency, omega, of the systemgIs the actual angular frequency of the grid.
8. The power droop-based photovoltaic grid-connected power generation system according to claim 1, wherein the step 2) of controlling the subsequent grid-connected inverter further comprises limiting the output current of the grid-connected inverter.
9. The power droop-based grid-connected photovoltaic power generation system of claim 8, wherein the current limiting further comprises controlling an output current according to formula (2):
wherein: kpIs the proportionality coefficient of the power loop, KiIs an integral coefficient of the power loop, P0Setting power, P, for a subsequent stage grid-connected invertereElectromagnetic power detected in real time.
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| CN113759184A (en) * | 2020-06-03 | 2021-12-07 | 台达电子企业管理（上海）有限公司 | Island detection method and device of inverter |
| US11936310B2 (en) | 2020-06-03 | 2024-03-19 | Delta Electronics (Shanghai) Co., Ltd | Control method and device for three-phase AC system |
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| CN113759184A (en) * | 2020-06-03 | 2021-12-07 | 台达电子企业管理（上海）有限公司 | Island detection method and device of inverter |
| TWI763456B (en) * | 2020-06-03 | 2022-05-01 | 大陸商台達電子企業管理（上海）有限公司 | Inverter islanding detection method and device |
| US11777322B2 (en) | 2020-06-03 | 2023-10-03 | Delta Electronics (Shanghai) Co., Ltd | Islanding detection mothod for inverter and apparatus |
| US11936310B2 (en) | 2020-06-03 | 2024-03-19 | Delta Electronics (Shanghai) Co., Ltd | Control method and device for three-phase AC system |
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