CN114665502A - LCL type photovoltaic grid-connected inverter control method and device based on feedforward compensation - Google Patents

LCL type photovoltaic grid-connected inverter control method and device based on feedforward compensation Download PDF

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CN114665502A
CN114665502A CN202210284011.1A CN202210284011A CN114665502A CN 114665502 A CN114665502 A CN 114665502A CN 202210284011 A CN202210284011 A CN 202210284011A CN 114665502 A CN114665502 A CN 114665502A
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difference value
grid
calculating
feedforward compensation
inverter
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潘三博
王旭
胡昭
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Shanghai Dianji University
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/01—Arrangements for reducing harmonics or ripples
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • 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
    • H02M7/539—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 with automatic control of output wave form or frequency
    • H02M7/5395—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 with automatic control of output wave form or frequency by pulse-width modulation
    • 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
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • 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

Abstract

The invention relates to a control method and a device of an LCL type photovoltaic grid-connected inverter based on feedforward compensation, wherein the method comprises the steps of obtaining the power grid voltage of the inverter, calculating the component of the power grid voltage in a two-phase static coordinate system, calculating the difference value of the power grid voltage and a voltage instruction value, and calculating the difference value through PI regulation and coordinate transformation to obtain a reference current signal; obtaining inverter side current, and obtaining an actual current signal through coordinate transformation; calculating the difference value between the reference current signal and the actual current signal, and inputting the difference value into a QPR regulator to obtain a reference modulation signal; acquiring the capacitance current of the inverter, calculating a difference value between the capacitance current and a reference modulation signal, performing PFC-based internal damping feedforward compensation after the difference value is gained, recalculating the difference value, and obtaining an output voltage command value after the gain; and transforming the coordinates into a three-phase static coordinate system, inputting the space vector pulse unit to obtain an SVPWM waveform, and inputting the SVPWM waveform into an inverter for control. Compared with the prior art, the invention has the advantages of simple control means, good control effect and the like.

Description

LCL type photovoltaic grid-connected inverter control method and device based on feedforward compensation
Technical Field
The invention relates to the field of inverter grid-connected control, in particular to a feedforward compensation-based LCL type photovoltaic grid-connected inverter control method and device.
Background
The grid-connected inverter is widely concerned as one of key interface devices in an alternating current micro-grid and a direct current micro-grid, and the performance of the grid-connected inverter is directly related to the quality of grid-connected current. In order to meet the network access harmonic standard, a filter is generally required to be connected in series between the alternating current side of the grid-connected inverter and a power grid. The output end of the traditional grid-connected inverter usually needs to select a larger filter inductor, so that the traditional grid-connected inverter is large in size and high in cost, and the dynamic performance of a system is influenced. To solve this problem, an LCL filter may be employed. Compared with the traditional L-shaped filter, the LCL filter is additionally provided with a capacitor branch circuit which has a small impedance value to high-frequency ripples, so that the ripple current injected into a power grid is reduced, but the LCL filter is a three-order system and has a resonance peak, which easily causes the instability of the system, so that in order to avoid the amplification of harmonic amplitude near resonance and the increase of the content of grid-connected current higher harmonics, a damping means is required to be adopted for inhibiting. There are generally two approaches, passive damping and active damping. The passive damping adds a damping unit in a circuit to eliminate a resonance peak, but the system can generate loss, an active damping method is adopted at the present stage, the damping is realized from the perspective of a control strategy, and commonly used methods such as virtual impedance, split capacitor and wave trap are adopted, and state quantity feedback methods such as capacitor current and capacitor voltage are adopted.
Grid-connected current tracking and harmonic current suppression of the grid-connected inverter are also the key points of control, and common control means include PI control, PR control, dead-beat control, hysteresis control, some intelligent control methods and the like. For a three-phase grid-connected system, PI control is simple and easy to implement, but fundamental frequency gain is limited, and the problems of steady-state error and poor anti-interference capability exist.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a control method and a control device of an LCL type photovoltaic grid-connected inverter based on feedforward compensation.
The purpose of the invention can be realized by the following technical scheme:
a control method of an LCL type photovoltaic grid-connected inverter based on feedforward compensation comprises the following steps:
s1, obtaining the grid voltage of the inverter, calculating the component of the grid voltage in a two-phase static coordinate system, calculating the difference value of the grid voltage and a voltage instruction value, and calculating the difference value through PI regulation and coordinate transformation to obtain a reference current signal;
s2, obtaining inverter side current, and obtaining an actual current signal through coordinate transformation;
s3, calculating the difference value between the reference current signal and the actual current signal, and inputting the difference value into a QPR regulator to obtain a reference modulation signal;
s4, acquiring the capacitance current of the inverter, calculating the difference value between the capacitance current and a reference modulation signal after coordinate transformation, performing PFC-based internal damping feedforward compensation after the difference value is gained, recalculating the difference value, and obtaining an output voltage command value after gaining;
and S5, converting the output voltage command value into a three-phase static coordinate system through coordinates, inputting the output voltage command value into a space vector pulse unit to obtain an SVPWM waveform, and inputting the SVPWM waveform into an inverter for control.
Further, the expression of the reference modulation signal generated by the QPR adjuster is as follows:
Figure BDA0003557421200000021
wherein s represents an error value between the reference current signal and the actual current signal, and the parameter KRRepresenting the amplitude gain at the fundamental frequency, parameter KPRepresenting the amplitude gain at low and high frequencies, ωcRepresenting the bandwidth, ω, of the system0Representing the angular frequency of resonance of the system.
Further, the compensation signal expression of the PFC based internal damping feedforward compensation is as follows:
Figure BDA0003557421200000022
Figure BDA0003557421200000023
wherein P represents a proportional gain, KPFCDenotes the damping constant, KPWMRepresenting the equivalent gain, G, of the inverterd(s) represents the calculation, sampling and PWM delays, Gic(s) denotes the uncompensated LCL filter transfer function, L1、L2And C denotes the inductance and capacitance of the LCL filter.
Further, the component calculation expression of the grid voltage in the two-phase stationary coordinate system is as follows:
Figure BDA0003557421200000031
wherein, Ua，UbAnd UcFor the grid voltage value, U, of the grid voltage in the three-phase stationary coordinate systemαAnd UβRepresenting the value of the grid voltage in a two-phase stationary frame.
Further, the manner of performing the gain on the difference in step S4 is a proportional gain.
An LCL type photovoltaic grid-connected inverter control device based on feedforward compensation comprises a memory and a processor; the memory for storing a computer program; the processor, when executing the computer program, is configured to implement the following method:
s1, obtaining the grid voltage of the inverter, calculating the component of the grid voltage in a two-phase static coordinate system, calculating the difference value of the grid voltage and a voltage instruction value, and calculating the difference value through PI regulation and coordinate transformation to obtain a reference current signal;
s2, obtaining inverter side current, and obtaining an actual current signal through coordinate transformation;
s3, calculating the difference value between the reference current signal and the actual current signal, and inputting the difference value into a QPR regulator to obtain a reference modulation signal;
s4, acquiring the capacitance current of the inverter, calculating the difference value between the capacitance current and a reference modulation signal after coordinate transformation, performing PFC-based internal damping feedforward compensation after the difference value is gained, recalculating the difference value, and obtaining an output voltage command value after the gain;
and S5, converting the output voltage command value into a three-phase static coordinate system through coordinates, inputting the output voltage command value into a space vector pulse unit to obtain an SVPWM waveform, and inputting the SVPWM waveform into an inverter for control.
Compared with the prior art, the invention has the following advantages:
1. the invention carries out coordinate conversion on each calculated parameter, and converts the three-phase coordinate system into the two-phase coordinate system, thereby simplifying the calculation flow in the control process; and a reference modulation signal is obtained through a QPR regulator, the value of the control signal is corrected through internal damping feedforward compensation after being compared with the capacitance current, the control of the inverter is completed only by arranging one compensator in a control circuit, the control is performed based on the parameters of the inverter, the control effect is good, and the cost is low.
2. The invention introduces proportional gain during feed forward compensation, ensures the stability margin of control signals and further improves the control effect of the inverter.
Drawings
Fig. 1 is a circuit diagram of an LCL type photovoltaic grid-connected inverter according to the present invention.
FIG. 2 is a schematic flow chart of the present invention.
FIG. 3 is a schematic diagram of coordinate transformation according to the present invention.
FIG. 4 is a block diagram of an LCL filter model in a two-phase coordinate system according to the present invention.
Fig. 5 is a simplified equivalent diagram of an LCL grid-connected inverter according to the present invention.
FIG. 6 is an equivalent control block diagram of the internal damping feedforward compensation of the present invention.
FIG. 7 is an overall control topology of the present invention.
FIG. 8 is a voltage-current simulation diagram according to the present invention.
FIG. 9 is a simulation diagram of voltage and current for one phase according to the present invention.
FIG. 10 is a voltage-current simulation diagram of the present invention during a voltage dip.
Fig. 11 is a comparison of bode plots for the control method of the present invention and for the no control method in the open loop case.
Fig. 12 is a bode plot comparison of the control method of the present invention and no control method in a closed loop situation.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
Fig. 1 shows a three-phase grid-connected inverter of an LCL type filter, the front end of which is a T-type three-level inverter, and the dc bus side voltage is UdcCurrent is idc(ii) a The DC side voltage-dividing capacitor is Cd1And Cd2The switching devices are all considered ideal devices. The AC side of the grid-connected inverter adopts L1、C、L2Representing an LCL type grid-connected filter. Inverter output voltage of U1a、U1b、U1cOutput current of i1a、i1bAnd i1c(ii) a The current flowing through the filter capacitor C is ica、icbAnd icc(ii) a The grid-connected current is i2a、i2bAnd i2c(ii) a Three-phase network voltage is Uga、UgbAnd UgcThe parasitic resistances of the inductor resistance and the filter capacitance are ignored.
The embodiment provides a method for controlling an LCL type photovoltaic grid-connected inverter based on feedforward compensation, as shown in fig. 2, the method includes the following steps:
step S1, the grid voltage U of the grid-connected inverter is sampled by the grid voltage sensorabcAnd each state variable of the mathematical model established under the three-phase static coordinate system is time-varying and has high order. In order to reduce system coupling variables and simplify a mathematical model, an LCL type grid-connected inverter model established under a three-phase static coordinate system is converted into a two-phase static coordinate system by Clark coordinate conversion, the conversion schematic diagram of the coordinate system is shown in FIG. 3, and a table of coordinate conversion formulasThe expression is as follows:
Figure BDA0003557421200000051
the coordinate-converted LCL filter model block diagram and the simplified equivalent diagram of the inverter are shown in fig. 4 and 5, respectively.
The components of the grid voltage vector in the static coordinate system can be obtained through a coordinate transformation formula from a three-phase static abc coordinate system to a two-phase static alpha beta coordinate system, and the expressions of the components are as follows:
Figure BDA0003557421200000052
and extracting the amplitude and the phase angle information of the power grid voltage through a phase-locked loop (PLL). Extracting the voltage U at the DC sidedcAnd the instruction value UdcComparing the reference current signal i obtained by the transformation of dq/alpha beta coordinates after PI regulation1α*、i1β*。
Step S2, sampling the inverter side current i by the inverter side current sensor1abcAnd the actual current signal i is transformed from a three-phase static abc coordinate system to a two-phase static alpha beta coordinate system under the coordinate transformation1αAnd i1β。
Step S3, reference current signal i1α*、i1βAnd the actual current signal i1α、i1βThe error value between the two is input into a QPR regulator to obtain a reference modulation signal. The QPR-based adjusting mode not only has the maximum amplitude gain at the resonant frequency point, can realize no-static tracking for given quantity without complex coordinate transformation, but also can effectively reduce line current harmonic when the power grid frequency deviates. Wherein, the QPR regulator outputs a reference modulation signal GQPR(s) the expression is as follows:
Figure BDA0003557421200000053
wherein s represents a referenceCurrent signal i1α*、i1βAnd the actual current signal i1α、i1βError value between, parameter KRRepresenting the amplitude gain at the fundamental frequency, parameter KPRepresenting the amplitude gain, ω, at low and high frequenciescRepresenting the bandwidth, ω, of the system0Representing the angular frequency of resonance of the system.
Step S4, sampling the capacitance current i by the filter capacitance current sensorcAnd obtaining a capacitance current signal i under a two-phase static alpha beta coordinate system through coordinate transformationcα、icβ. And after the difference between the capacitance current signal and the reference modulation signal is obtained, obtaining an output voltage instruction value through P gain and internal damping feedforward compensation.
The equivalent control block diagram of the internal damping feedforward compensation is shown in fig. 6, and the expression of the internal damping is as follows:
Figure BDA0003557421200000054
Figure BDA0003557421200000061
wherein P represents a proportional gain, KPFCDenotes the damping constant, KPWMDenotes the equivalent gain, G, of the inverterd(s) represents the calculation, sampling and PWM delays, Gic(s) represents the uncompensated LCL filter transfer function.
And step S5, performing coordinate transformation on the output voltage command value, transforming the output voltage command value from a two-phase static alpha beta coordinate system to a three-phase static abc coordinate system, sending the output voltage command value into a space vector pulse unit to generate an SVPWM waveform, and finally sending the SVPWM waveform into an inverter unit to drive the switching tube to be switched on and off so as to control the inverter to work. The overall control block diagram is shown in fig. 7.
A simulation test is performed, fig. 8 is a voltage-current simulation graph, fig. 9 is a voltage-current simulation graph of one phase, and fig. 10 is a voltage-current simulation graph at the time of voltage dip, as can be seen from the waveforms in fig. 8 to fig. 10, under the control of this embodiment, the grid-connected current can reach a stable frequency amplitude, and can realize fast and stable tracking when the current command changes.
Fig. 11 is a bode plot comparison of the control method and the non-control method of the present embodiment in the open loop case, and fig. 12 is a bode plot comparison of the control method and the non-control method of the present embodiment in the closed loop case. As can be seen from the variation curves of fig. 11 to 12, the method (PFC) widens the effective damping interval. Has fast dynamic response, good tracking performance and resonance suppression capability.
Meanwhile, as can be seen from the closed loop frequency response, the method has better phase characteristics and higher gain at a low frequency band, which shows that the method has good low-order harmonic suppression capability under the condition of power grid voltage distortion.
The embodiment also provides an LCL type photovoltaic grid-connected inverter control device based on feedforward compensation, which comprises a memory and a processor; a memory for storing a computer program; and the processor is used for realizing the LCL type photovoltaic grid-connected inverter control method based on the feedforward compensation when executing a computer program.
The present embodiment also provides a computer-readable storage medium, on which a computer program is stored, which when executed by a processor implements the LCL-type pv grid-connected inverter control method based on feedforward compensation as mentioned in the above embodiments, and any combination of one or more computer-readable media may be adopted. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.

Claims (10)

1. The LCL type photovoltaic grid-connected inverter control method based on feedforward compensation is characterized by comprising the following steps:
s1, obtaining the grid voltage of the inverter, calculating the component of the grid voltage in a two-phase static coordinate system, calculating the difference value of the grid voltage and a voltage instruction value, and calculating the difference value through PI regulation and coordinate transformation to obtain a reference current signal;
s2, obtaining inverter side current, and obtaining an actual current signal through coordinate transformation;
s3, calculating the difference value between the reference current signal and the actual current signal, and inputting the difference value into a QPR regulator to obtain a reference modulation signal;
s4, acquiring the capacitance current of the inverter, calculating the difference value between the capacitance current and a reference modulation signal after coordinate transformation, performing PFC-based internal damping feedforward compensation after the difference value is gained, recalculating the difference value, and obtaining an output voltage command value after the gain;
and S5, converting the output voltage command value into a three-phase static coordinate system through coordinates, inputting the output voltage command value into a space vector pulse unit to obtain an SVPWM waveform, and inputting the SVPWM waveform into an inverter for control.
2. The LCL type photovoltaic grid-connected inverter control method based on feedforward compensation according to claim 1, wherein the expression of the reference modulation signal generated by the QPR regulator is as follows:
Figure FDA0003557421190000011
wherein s represents an error value between the reference current signal and the actual current signal, and the parameter KRRepresenting the amplitude gain at fundamental frequency, parameter KPRepresenting the amplitude gain, ω, at low and high frequenciescRepresenting the bandwidth, ω, of the system0Representing the angular frequency of resonance of the system.
3. The LCL type photovoltaic grid-connected inverter control method based on feedforward compensation as claimed in claim 1, wherein the compensation signal based on the internal damping feedforward compensation of PFC is expressed as follows:
Figure FDA0003557421190000012
Figure FDA0003557421190000013
wherein P represents a proportional gain, KPFCDenotes the damping constant, KPWMRepresenting the equivalent gain, G, of the inverterd(s) represents the calculation, sampling and PWM delays, Gic(s) denotes the uncompensated LCL filter transfer function, L1、L2And C denotes the inductance and capacitance of the LCL filter.
4. The LCL type photovoltaic grid-connected inverter control method based on the feedforward compensation as claimed in claim 1, wherein the component calculation expression of the grid voltage in the two-phase static coordinate system is as follows:
Figure FDA0003557421190000021
wherein, Ua，UbAnd UcFor the grid voltage value, U, of the grid voltage in the three-phase stationary coordinate systemαAnd UβRepresenting the value of the grid voltage in a two-phase stationary frame.
5. The LCL type photovoltaic grid-connected inverter control method based on feedforward compensation as claimed in claim 1, wherein the gain of the difference in step S4 is proportional gain.
6. The LCL type photovoltaic grid-connected inverter control device based on feedforward compensation is characterized by comprising a memory and a processor; the memory for storing a computer program; the processor, when executing the computer program, is configured to implement the following method:
s1, obtaining the grid voltage of the inverter, calculating the component of the grid voltage in a two-phase static coordinate system, calculating the difference value of the grid voltage and a voltage instruction value, and calculating the difference value through PI regulation and coordinate transformation to obtain a reference current signal;
s2, obtaining inverter side current, and obtaining an actual current signal through coordinate transformation;
s3, calculating the difference value between the reference current signal and the actual current signal, and inputting the difference value into a QPR regulator to obtain a reference modulation signal;
s4, acquiring the capacitance current of the inverter, calculating the difference value between the capacitance current and a reference modulation signal after coordinate transformation, performing PFC-based internal damping feedforward compensation after the difference value is gained, recalculating the difference value, and obtaining an output voltage command value after the gain;
and S5, converting the output voltage command value into a three-phase static coordinate system through coordinates, inputting the output voltage command value into a space vector pulse unit to obtain an SVPWM waveform, and inputting the SVPWM waveform into an inverter for control.
7. The LCL type photovoltaic grid-connected inverter control device based on feedforward compensation according to claim 6, wherein the expression of the reference modulation signal generated by the QPR regulator is as follows:
Figure FDA0003557421190000022
wherein s represents an error value between the reference current signal and the actual current signal, and the parameter KRRepresenting the amplitude gain at the fundamental frequency, parameter KPRepresenting the amplitude gain, ω, at low and high frequenciescRepresenting the bandwidth, ω, of the system0Representing the angular frequency of resonance of the system.
8. The LCL type photovoltaic grid-connected inverter control device based on feedforward compensation as claimed in claim 6, wherein the compensation signal based on the internal damping feedforward compensation of PFC is expressed as follows:
Figure FDA0003557421190000031
Figure FDA0003557421190000032
wherein P represents a proportional gain, KPFCDenotes the damping constant, KPWMRepresenting the equivalent gain, G, of the inverterd(s) represents the calculation, sampling and PWM delays, Gic(s) denotes the uncompensated LCL filter transfer function, L1、L2And C denotes the inductance and capacitance of the LCL filter.
9. The LCL type photovoltaic grid-connected inverter control device based on feedforward compensation according to claim 6, wherein the component calculation expression of the grid voltage in the two-phase static coordinate system is as follows:
Figure FDA0003557421190000033
wherein，Ua，UbAnd UcFor the grid voltage value, U, of the grid voltage in the three-phase stationary coordinate systemαAnd UβRepresenting the value of the grid voltage in a two-phase stationary frame.
10. The LCL type photovoltaic grid-connected inverter control device based on feedforward compensation as claimed in claim 6, wherein the gain of the difference in step S4 is proportional gain.
CN202210284011.1A 2022-03-21 2022-03-21 LCL type photovoltaic grid-connected inverter control method and device based on feedforward compensation Pending CN114665502A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116632947A (en) * 2023-07-21 2023-08-22 华能江苏综合能源服务有限公司 Grid-connected inverter transient stability area improvement control method and system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116632947A (en) * 2023-07-21 2023-08-22 华能江苏综合能源服务有限公司 Grid-connected inverter transient stability area improvement control method and system
CN116632947B (en) * 2023-07-21 2023-12-05 华能江苏综合能源服务有限公司 Grid-connected inverter transient stability area improvement control method and system

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