Robust discrete linear quadratic control applied to grid-connected converters with LCL filters

Maccari, Luiz A.; Santini, Claudio Luiz do Amarai; Oliveira, Ricardo C. L. F.; Montagner, Vinícius F.

doi:10.1109/cobep.2013.6785143

Cited by 8 publications

(6 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An additional integral feedback allows for stationary accuracy and is considered in the DLQR controller design. In [35], solely a DLQR current controller for a single-phase GCI with LCL filter is proposed. The current controller is designed by using linear matrix inequality conditions.…”

Section: Kv a Lclmentioning

confidence: 99%

“…All of the contributions above rely on (i) a rather large dc-link capacitance (see Table 1) and/or (ii) a rather large ratio between switching frequency and filter resonance frequency (in e.g., [35], this ratio is 20,040 Hz/1744 Hz = 11.5, which shows that a discrete-time controller design is actually not needed). This paper focuses on the control of a GCI with a very small dc-link capacitor and an LCL filter where the resonance frequency is very close to the switching frequency.…”

Section: Kv a Lclmentioning

confidence: 99%

See 1 more Smart Citation

Discrete-Time DC-Link Voltage and Current Control of a Grid-Connected Inverter with LCL-Filter and Very Small DC-Link Capacitance

2020

View full text Add to dashboard Cite

The paper presents a controller design for grid-connected inverters (GCI) with very small dc-link capacitance that are coupled to the grid via an LCL filter. The usual controller designs would fail and result in instability. The proposed controller has a cascaded structure with a current controller as inner control loop and an outer dc-link voltage controller. The controller design is performed in discrete time and it is based on a detailed stability analysis of the dc-link voltage controller to determine the controller parameters which guarantee stability for all operating points. The inner loop is a state-feedback current controller that is designed based on the discrete linear-quadratic regulator (DLQR) theory. An additional integral error feedback assures steady-state accuracy of the current control loop. The simulation and experimental results validate performance and stability of proposed controller design.

show abstract

Section: Kv a Lclmentioning

confidence: 99%

Section: Kv a Lclmentioning

confidence: 99%

Discrete-Time DC-Link Voltage and Current Control of a Grid-Connected Inverter with LCL-Filter and Very Small DC-Link Capacitance

2020

View full text Add to dashboard Cite

show abstract

“…Resonant controllers are widely used to suppress harmonic components and provide efficient performance in electrical power applications [10,11]. This system can be represented by a second-order system with a specifically tuned frequency for ensuring steady-state error.…”

Section: Introductionmentioning

confidence: 99%

“…Literature [11], shows employment of multi resonant controller and estimation of the state matrix and the state-feedback gain. Moreover, the controller does not have an integrator.…”

Section: Introductionmentioning

confidence: 99%

Multi-Objective Flower Pollination Algorithm Based Controller for UPQC Including Hybrid Power Source

Hussain*,

Sridhar

2020

IJITEE

View full text Add to dashboard Cite

This paper presents a new control method for Unified Power Quality Conditioner (UPQC) for effective management of the power-sharing and improvement of the quality of power. The voltage disturbances produced in the source side due to non-linear load conditions can be protected using the UPQC model. Flexible Alternating Current Transmission System (FACTS) devices were fed through a hybrid power generator that had the primary source, a Proton Exchange Membrane Fuel Cell (PEMFC) and a secondary source, a supercapacitor. In this paper, a multi-objective function (power factor, voltage sag, and the total harmonic distortion (THD)) with different control strategies have been considered. An optimization algorithm named Flower Pollination Algorithm (FPA) has used for optimizing Proportional Integral (PI) coefficients. A suitable fitness function has been developed for the FPA method and the simulation performed. The performance of the FPA method has been compared with three different algorithms, namely, particle swarm optimization algorithm (PSOA), Differential Evolution Algorithm (DEA), and Ant Colony Optimization Algorithm (ACOA). The result obtained shows the proposed FPA providing the best result compared to other methods.

show abstract

“…Robust control based on LMIs was addressed for single‐phase inverter connected to the grid through LCL filter in [17, 18] based on a pole location design. In [39], the control action is given by the feedback of the filter states and the internal states of one resonant controller tuned at the fundamental frequency. Good simulation results are provided and the control gains of a discrete‐time LQ regulator (DLQR), which are robust to grid parametric uncertainty, are obtained from a convex optimisation problem based on LMIs.…”

Section: Introductionmentioning

confidence: 99%

Robust optimal current control for grid‐connected three‐phase pulse‐width modulated converters

Maccari

Santini

Pinheiro

et al. 2015

IET Power Electronics

Self Cite

View full text Add to dashboard Cite

This study deals with the current control of three-phase inverters connected to the grid by means of LCL filters. The control action is given by the feedback of the filter states, in coordinates αβ0, and of the internal states of resonant controllers. The control gains are computed by means of an optimal linear quadratic regulator that is robust to uncertain and time-varying parameters related to the grid impedance at the point of common coupling. As contributions, one has the detailed proof of a robust discrete linear quadratic control, showing its applicability also for the time-varying case, the experimental validation of the results in terms of the total harmonic distortion and harmonic limits for the grid injected current, according to the IEEE 1547 standard, and the analysis of the ℋ ∞ norm of the closedloop system for several values of grid inductance, indicating a value of grid inductance for which one has best performance for the time-invariant case. For comparison, a conventional state feedback controller is designed and implemented, showing the limitation of the non-robust strategy.

show abstract

Robust discrete linear quadratic control applied to grid-connected converters with LCL filters

Cited by 8 publications

References 17 publications

Discrete-Time DC-Link Voltage and Current Control of a Grid-Connected Inverter with LCL-Filter and Very Small DC-Link Capacitance

Discrete-Time DC-Link Voltage and Current Control of a Grid-Connected Inverter with LCL-Filter and Very Small DC-Link Capacitance

Multi-Objective Flower Pollination Algorithm Based Controller for UPQC Including Hybrid Power Source

Robust optimal current control for grid‐connected three‐phase pulse‐width modulated converters

Contact Info

Product

Resources

About