CN113067372A - Active damping method and circuit for improving LCL filtering grid-connected control performance - Google Patents

Active damping method and circuit for improving LCL filtering grid-connected control performance Download PDF

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CN113067372A
CN113067372A CN202110360531.1A CN202110360531A CN113067372A CN 113067372 A CN113067372 A CN 113067372A CN 202110360531 A CN202110360531 A CN 202110360531A CN 113067372 A CN113067372 A CN 113067372A
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current
grid
lcl
improving
damping
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曼苏乐
徐雅梅
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CHANGZHOU TIANMAN INTELLIGENT TECHNOLOGY CO LTD
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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
    • 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
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • H02J3/241—The oscillation concerning frequency
    • 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
    • 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
    • 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
    • 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
    • H02J2300/28—The renewable source being wind energy
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

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Abstract

The invention relates to an active damping method and a circuit for improving LCL filtering grid-connected control performance, wherein the active damping method is realized based on a capacitance current average method suitable for damping loop design, and comprises the following steps: collecting the current of a tested power grid and the current of a tested capacitor of an LCL filter; calculating and obtaining an average capacitance current in a switching period based on the measured capacitance current; eliminating the resonance frequency component in the average capacitance current to obtain a compensation capacitance current; generating a modulation signal based on the compensation capacitance current and the current of the tested power grid; and performing PWM modulation based on the modulation signal to realize active damping control. Compared with the prior art, the invention has the advantages of effectively eliminating high-frequency and noise signal components, ensuring the capacitance current damping in the high-power converter and the like.

Description

Active damping method and circuit for improving LCL filtering grid-connected control performance
Technical Field
The invention relates to an LCL filtering grid-connected inverter, in particular to an active damping method and circuit for improving LCL filtering grid-connected control performance.
Background
To meet the increasing demand for renewable energy sources (i.e., solar and wind energy), the grid-connected number of Distributed Generation (DG) devices based on renewable energy sources is increasing exponentially. Voltage Source Inverters (VSIs) are typically interfaced through LCL filters due to their high power quality and cost effectiveness. However, resonance problems in LCL filters cause resonant frequency oscillations when the filter parameters drift, degrading control performance. Passive and active damping methods are mainly achieved by physically adding passive components and modifying the inverter control structure. Active Damping (AD) is considered a more suitable approach due to its advantages of lossless damping, flexible design, better harmonic attenuation, etc.
Several active damping methods have been applied in the prior art, such as single loop damping, grid current damping or capacitive voltage damping. Among these methods, the capacitive current method is popular due to effective resonance suppression and high quality of injected grid current. A constant damping coefficient as a damping compensator in the capacitive current feedback path is a simple design technique. However, due to variations in the filter parameters or the grid impedance, damping may become ineffective at critical resonance frequencies and compromise the stability of the control loop. In order to improve the robustness of the system, a damping compensator based on a differential function, such as a derivative, a first-order high-pass filter, a second-order generalized integral or a proportional integral, is adopted in the capacitance current feedback damping loop. The parallel feedforward compensation method is another alternative structure for realizing the capacitance current damping loop. Delay minimization techniques can also be used for capacitive current damping with good robustness. However, the common denominator of the above methods is that the measured capacitance current is directly used in the damping loop. The measured capacitance current contains high frequency components and noise signals, and particularly when the switching frequency is thousands of hertz (kHz), the noise signals limit the compensation of the capacitance current. This limitation leads to a deterioration of the performance of the capacitive current damping loop, especially in the design of high power converters.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide an active damping method and circuit for improving the LCL filtering grid-connected control performance.
The purpose of the invention can be realized by the following technical scheme:
an active damping method for improving LCL filtering grid-connected control performance is realized based on a capacitance current average method suitable for damping loop design, and comprises the following steps:
collecting the current of a tested power grid and the current of a tested capacitor of an LCL filter;
calculating and obtaining an average capacitance current in a switching period based on the measured capacitance current;
eliminating the resonance frequency component in the average capacitance current to obtain a compensation capacitance current;
generating a modulation signal based on the compensation capacitance current and the current of the tested power grid;
and performing PWM modulation based on the modulation signal to realize active damping control.
Further, the measured capacitance current includes high frequency components, noise signals, and current spikes.
Further, the generating of the modulation signal based on the compensation capacitance current and the current of the measured power grid specifically includes:
obtaining an error current signal based on the measured power grid current and a preset reference current value, and adjusting the error current signal to generate a compensation error current signal;
subtracting the compensation capacitance current from the compensation error current signal to generate a modulation signal.
The invention also provides an active damping control circuit for improving the LCL filtering grid-connected control performance, which comprises an inverter, an LCL filter, a grid voltage source, a current loop, a damping loop and a PWM module, wherein the inverter, the LCL filter and the grid voltage source are sequentially connected, the damping loop is respectively connected with the LCL filter and the PWM module, the current loop is respectively connected with the LCL filter and the damping loop, the PWM module is connected with the inverter, the damping loop comprises a resettable integrator and a damping compensator which are connected, the resettable integrator receives the measured capacitance current of the LCL filter, the average capacitance current in a switching period is obtained by calculation based on the measured capacitance current and is fed into the damping compensator, the damping compensator generates a compensating capacitance current, and a modulation signal is generated based on the compensating capacitance current and a compensating error current signal obtained by the current loop, feeding the PWM module.
Further, the resettable signal of the resettable integrator is provided by the PWM module.
Further, the average capacitance current is calculated in the resettable integrator from the difference between the previous and present output capacitance current values in two consecutive switching cycles.
Further, the damping compensator is a compensator based on a constant damping coefficient or derivative.
Further, the current loop comprises a current controller, and the current controller generates a compensation error current signal based on the difference value between the measured power grid current and a preset reference current value.
Further, the current controller includes a proportional integral controller or a proportional resonant controller.
Further, discrete-time modeling is performed on the LCL filter, and the obtained average capacitance current is represented as:
Figure BDA0003005369320000031
Figure BDA0003005369320000032
Figure BDA0003005369320000033
in the formula, L1、R1For inverting side inductance and resistance, L2、R2For grid-side inductances and resistances, CfIs a filter capacitor, dkIs the duty cycle of k instantsc_kIn order to sample the voltage of the capacitor,
Figure BDA0003005369320000034
in order to average the output voltage of the inverter,
Figure BDA0003005369320000035
to average grid voltage, TsIs a switching cycle.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the invention, the average sampling value of the measured capacitance current is obtained by an averaging method, so that high-frequency noise components in the measured capacitance current are effectively filtered, the capacitance current damping in a high-power converter is ensured, the performance of a damping loop is improved, and a good improvement scheme is provided for the capacitance current damping performance of a grid-connected inverter.
2. The invention can effectively eliminate noise and switching signals in the capacitance current, enhance the effectiveness and performance of the damping loop and improve the quality of grid injection current.
3. The invention can be effectively applied to the design of the inverter with low switching frequency and high switching frequency.
4. Due to the large bandwidth, the transient response under load disturbance and load change conditions is improved.
Drawings
Fig. 1 is a schematic circuit structure diagram of a conventional LCL filtering grid-connected inverter;
FIG. 2 is a schematic diagram of a circuit structure of the LCL filtering grid-connected inverter of the invention;
FIG. 3 is an equivalent control diagram of the LCL filtering grid-connected inverter of the present invention;
fig. 4 is a schematic diagram of voltage and current waveforms of the inverter after the method of the invention is adopted.
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.
Example 1
The embodiment provides an active damping method for improving LCL filtering grid-connected control performance, which comprises the following steps: collecting the current of a tested power grid and the current of a tested capacitor of an LCL filter, wherein the current comprises high-frequency components, noise signals and current spikes; calculating and obtaining an average capacitance current in a switching period based on the measured capacitance current; eliminating the resonance frequency component in the average capacitance current to obtain a compensation capacitance current; generating a modulation signal based on the compensation capacitance current and the current of the tested power grid; and performing PWM modulation based on the modulation signal to realize active damping control. The generation of the modulation signal based on the compensation capacitance current and the current of the measured power grid specifically comprises: obtaining an error current signal based on the measured power grid current and a preset reference current value, and adjusting the error current signal to generate a compensation error current signal; subtracting the compensation capacitance current from the compensation error current signal to generate a modulation signal.
The method innovatively provides a civil capacitance current averaging method to eliminate high-frequency and noise signal components, ensure capacitance current damping in a high-power converter and overcome the difficulty of designing a damping loop based on capacitance current due to the existence of a high-frequency switch and a noise signal in the measured capacitance current.
FIG. 4 shows the grid voltage v after the method of the invention has been usedgThe current i of the measured power gridgThe measured capacitance current icAnd average capacitance current
Figure BDA0003005369320000041
The waveform of (2). The waveform being sinusoidal
Figure BDA0003005369320000042
Indicating that the high frequency switching and noise signal components are effectively eliminated.
In other embodiments, the method of the present invention can be implemented in the following application fields together with the LCL filter
1. The grid-connected inverter is used for integrating renewable energy sources such as solar energy, wind energy and the like;
2. the method can be used for designing single-phase and three-phase inverters;
3. an inverter operable to operate independently;
4. the method can be used for designing the inverter of equipment such as a synchronous static compensator (STATCOM) or a Static Var Generator (SVG) and the like so as to improve the power quality of a power distribution system.
Example 2
The present embodiment designs a circuit structure of the LCL filtering grid-connected inverter according to the method described in embodiment 1.
As shown in fig. 1, the conventional LCL filtering Grid-connected inverter includes an H-Bridge single-phase inverter (H-Bridge DC-AC Converter)1, an LCL Filter (LCL-Filter)2, a Grid voltage source (Grid)3, a current loop 4, a damping loop 5, and a PWM module 6, wherein the H-Bridge single-phase inverter is composed of switching devices such as Insulated Gate Bipolar Transistors (IGBTs) and converts an input voltage VDC into an inverter output voltage vinvSupplying power; the LCL filter consists of an inverter side resistor, an inverter side inductor, a network side resistor, an inductor and a filter capacitor, and the output of the LCL filter is measured capacitance current icAnd grid current; voltage of the network voltage source is vg(ii) a The current loop 4 is based on the current i of the tested power grid2And a reference current value
Figure BDA0003005369320000051
The difference of (d) obtains an error current delta1And a Current Controller (Current Controller) is adopted to control the error Current delta1Making adjustments to produce a compensated error current signal delta2(ii) a A damping circuit 5 consisting ofcAnd delta2Supporting, by Damping Compensator (damper Compensator) to icProcessing to obtain compensated capacitance current delta icModulating signal umBy delta2And δ icCalculating the difference; modulated signal umThe pulses are input to a modulator in the PWM module 6, and are gate-driven to generate gate pulses G1 to G4 for the inverter unit IGBTs. However, in the existing multi-loop damping method, the capacitive current damping contains high frequency noise signals in the measured capacitive current, which limits the performance of the damping loop and the quality of the capacitive current damping loop injecting the grid current, especially at lower sampling frequencies.
In the embodiment, on the basis of fig. 1, the damping circuit 5 is designed in an improved manner. As shown in fig. 2, the damping loop 5 of the present embodiment includes a Resettable Integrator (Resettable Integrator) and a damping compensator, the Resettable Integrator is used for measuring the capacitanceCurrent icConversion to average capacitance current
Figure BDA0003005369320000052
Then fed into a damping compensator which averages the capacitive current
Figure BDA0003005369320000053
Performing subsequent processing based on the output of the compensation capacitance current delta ic. Resettable signal u of resettable integratorsSupplied by a modulator in the PWM module 6, synchronized with the carrier signal in the PWM module and during each switching period TsThe integrator is reset once. The average value in the resettable integrator is calculated from the difference between the previous and current output capacitor current values over two consecutive switching cycles. In this embodiment, the input of the damping compensator is the average capacitance current, not the measured capacitance current ic。
For current loop design, the net side current i is measured2And from a reference current value
Figure BDA0003005369320000054
To generate an error current signal delta1. The error current is regulated by a current controller module, which may be a Proportional Integral (PI), Proportional Resonant (PR), or any other type of controller, that generates a compensated error current signal δ2. Compensating the capacitive current δ icAnd a current controller delta2Calculating a modulation signal u from the difference between the outputs ofmAnd comparing with the carrier signal, changing the duty ratio of gate pulse to regulate the on-off of the switching device of the switching type inverter and correspondingly regulating the current i on the side of the inverter1,、i2And ic. The generated gate pulse adjusts the on-off pattern of the switching device according to the change of the duty ratio, and thus the compensation effect of the average capacitance current method in the present invention is necessary. The adjustment of the inverter switching mode affects the inverter output voltage, the inverter-side grid, the grid-side current, the capacitor current and the voltage, and the overall control performance of the inverter can be improved.
Fig. 3 shows an equivalent control diagram of the inverter shown in fig. 2. Fig. 3 combines the averaging of the capacitor current with modeling of the LCL filter, the input comprising the inverter output voltage vinvResettable signal usAnd the network voltage vg(ii) a The modulation, gate signal generation and inversion unit is represented by a single module; a current controller, denoted by c (z), adjusts the error current signal calculated from the reference difference, measuring the grid current to implement the current loop.
An inverter control scheme based on a capacitance current average method is designed by modeling discrete time of an LCL filter device. The state space of the LCL filter discrete time model is represented as follows:
Figure BDA0003005369320000061
Figure BDA0003005369320000062
in the formula i1_k+1,i2_k+1And vc_k+1Is a state variable i1,i2And vcAnd calculating corresponding immediate early sampling values.
Figure BDA0003005369320000063
And
Figure BDA0003005369320000064
is the input variable of the filter. I is2_kAnd
Figure BDA0003005369320000065
is the output variable, the state matrix A1Input matrix B1Output matrix C1And a feedforward matrix D1The detailed expression of (a) is as follows:
Figure BDA0003005369320000066
Figure BDA0003005369320000067
Figure BDA0003005369320000068
Figure BDA0003005369320000069
during a switching time period TsHas an average capacitance current of 'k' at the instant of
Figure BDA00030053693200000610
It depends on the capacitance current i sampled at the same instantc_kAnd can be converted into an inverter-side current i1_kAnd the current i on the grid side2_kOf the sampling value(s). After discrete time modeling of the LCL filter arrangement, the average capacitance current formula of the present invention is as follows:
Figure BDA00030053693200000611
in the formula (I), the compound is shown in the specification,
Figure BDA00030053693200000612
Figure BDA00030053693200000613
L1,R1for inverting side inductance and resistance, L2,R2For grid-side inductances and resistances, CfIs a filter capacitor, dkIs the duty cycle at the instant of "k", vc_kIn order to sample the voltage of the capacitor,
Figure BDA0003005369320000071
in order to average the output voltage of the inverter,
Figure BDA0003005369320000072
is the average grid voltage.
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. An active damping method for improving LCL filtering grid-connected control performance is characterized by comprising the following steps:
collecting the current of a tested power grid and the current of a tested capacitor of an LCL filter;
calculating and obtaining an average capacitance current in a switching period based on the measured capacitance current;
eliminating the resonance frequency component in the average capacitance current to obtain a compensation capacitance current;
generating a modulation signal based on the compensation capacitance current and the current of the tested power grid;
and performing PWM modulation based on the modulation signal to realize active damping control.
2. The active damping method for improving the LCL filtering grid-connected control performance according to claim 1, wherein the measured capacitance current comprises high frequency components, noise signals and current spikes.
3. The active damping method for improving the LCL filtering grid-connected control performance according to claim 1, wherein the generation of the modulation signal based on the compensation capacitor current and the measured grid current specifically comprises:
obtaining an error current signal based on the measured power grid current and a preset reference current value, and adjusting the error current signal to generate a compensation error current signal;
subtracting the compensation capacitance current from the compensation error current signal to generate a modulation signal.
4. An active damping control circuit for improving LCL filtering grid-connected control performance comprises an inverter, an LCL filter, a power grid voltage source, a current loop, a damping loop and a PWM module, wherein the inverter, the LCL filter and the power grid voltage source are sequentially connected, the damping loop is respectively connected with the LCL filter and the PWM module, the current loop is respectively connected with the LCL filter and the damping loop, and the PWM module is connected with the inverter. Feeding the PWM module.
5. The active damping control circuit for improving the LCL filtering grid-connected control performance according to claim 4, wherein the resettable signal of the resettable integrator is provided by the PWM module.
6. The active damping control circuit for improving the LCL filtering grid-connected control performance according to claim 4, wherein the average capacitance current is obtained in the resettable integrator by calculating the difference between the previous and the current output capacitance current values in two consecutive switching cycles.
7. The active damping control circuit for improving the LCL filtering grid-connected control performance according to claim 4, wherein the damping compensator is a compensator based on a constant damping coefficient or derivative.
8. The active damping control circuit for improving the LCL filtering grid-connected control performance according to claim 4, wherein the current loop comprises a current controller, and the current controller generates a compensation error current signal based on the difference between the measured grid current and a preset reference current value.
9. The active damping control circuit for improving the LCL filtering grid-connected control performance according to claim 8, wherein the current controller comprises a proportional integral controller or a proportional resonant controller.
10. The active damping control circuit for improving the LCL filtering grid-connected control performance according to claim 4, wherein the LCL filter is subjected to discrete time modeling, and the obtained average capacitance current is represented as:
Figure FDA0003005369310000021
Figure FDA0003005369310000022
Figure FDA0003005369310000023
in the formula, L1、R1For inverting side inductance and resistance, L2、R2For grid-side inductances and resistances, CfIs a filter capacitor, dkIs the duty cycle of k instantsc_kIn order to sample the voltage of the capacitor,
Figure FDA0003005369310000024
in order to average the output voltage of the inverter,
Figure FDA0003005369310000025
to average grid voltage, TsIs a switching cycle.
CN202110360531.1A 2021-04-02 2021-04-02 Active damping method and circuit for improving LCL filtering grid-connected control performance Pending CN113067372A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116539949A (en) * 2023-07-04 2023-08-04 杰华特微电子股份有限公司 Current detection device, detection method and switching circuit of H-bridge circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116539949A (en) * 2023-07-04 2023-08-04 杰华特微电子股份有限公司 Current detection device, detection method and switching circuit of H-bridge circuit

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