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17 pages, 5658 KiB

Open AccessArticle

A Robust Nonlinear Controller for PMSG Wind Turbines

by Nicholas Hawkins and Michael L. McIntyre

Energies 2021, 14(4), 954; https://doi.org/10.3390/en14040954 - 11 Feb 2021

Cited by 4 | Viewed by 1360

In this paper, a nonlinear backstepping controller is proposed to manage the performance of a full-variable permanent magnet synchronous generator wind turbine. This nonlinear controller achieves a rotational speed objective for the generator and is validated through Lyapunov-based stability analysis. Additionally, this objective [...] Read more.

In this paper, a nonlinear backstepping controller is proposed to manage the performance of a full-variable permanent magnet synchronous generator wind turbine. This nonlinear controller achieves a rotational speed objective for the generator and is validated through Lyapunov-based stability analysis. Additionally, this objective is accomplished without a measurement for wind speed that influences the wind torque. The proposed scheme is compared to a typical linear controller through simulation results. Simulation tests are performed to compare the response time and average error of each controller in both a drastic and realistic dynamic wind environment. These results demonstrate that the proposed controller is far more robust to wind turbulence than traditional control schemes. The simulation results of this study indicate a 1000% increase in response time and 3000% decrease in average controller error. Full article

(This article belongs to the Special Issue Advanced Control Applications for Electrical Energy Systems)

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17 pages, 6426 KiB

Open AccessArticle

Load Frequency Regulator in Interconnected Power System Using Second-Order Sliding Mode Control Combined with State Estimator

by Anh-Tuan Tran, Bui Le Ngoc Minh, Van Van Huynh, Phong Thanh Tran, Emmanuel Nduka Amaefule, Van-Duc Phan and Tam Minh Nguyen

Energies 2021, 14(4), 863; https://doi.org/10.3390/en14040863 - 7 Feb 2021

Cited by 16 | Viewed by 2668

Abstract

In multi-area interconnected power systems (MAIPS), the measurement of all system states is difficult due to the lack of a sensor or the fact that it is expensive to measure. In order to solve this limitation, a new load frequency controller based on [...] Read more.

In multi-area interconnected power systems (MAIPS), the measurement of all system states is difficult due to the lack of a sensor or the fact that it is expensive to measure. In order to solve this limitation, a new load frequency controller based on the second-order sliding mode is designed for MAIPS where the estimated state variable is used fully in the sliding surface and controller. Firstly, a model of MAIPS integrated with disturbance is introduced. Secondly, an observer has been designed and used to estimate the unmeasured variables with disturbance. Thirdly, a new second-order sliding mode control (SOSMC) law is used to reduce the chattering in the system dynamics where slide surface and sliding mode controller are designed based on system states observer. The stability of the whole system is guaranteed via the Lyapunov theory. Even though state variables are not measured, the experimental simulation results show that the frequency remains in the nominal range under load disturbances, matched and mismatched uncertainties of the MAIPS. A comparison to other controllers illustrates the superiority of the highlighted controller designed in this paper. Full article

(This article belongs to the Special Issue Advanced Control Applications for Electrical Energy Systems)

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17 pages, 4649 KiB

Open AccessArticle

Nonlinear Current-Mode Control of SCIG Wind Turbines

by Nicholas Hawkins, Bhagyashri Bhagwat and Michael L. McIntyre

Energies 2021, 14(1), 55; https://doi.org/10.3390/en14010055 - 24 Dec 2020

Cited by 3 | Viewed by 1842

Abstract

In this paper, a nonlinear controller is proposed to manage the rotational speed of a full-variable Squirrel Cage Induction Generator wind turbine. This control scheme improves upon tractional vector controllers by removing the need for a rotor flux observer. Additionally, the proposed controller [...] Read more.

In this paper, a nonlinear controller is proposed to manage the rotational speed of a full-variable Squirrel Cage Induction Generator wind turbine. This control scheme improves upon tractional vector controllers by removing the need for a rotor flux observer. Additionally, the proposed controller manages the performance through turbulent wind conditions by accounting for unmeasurable wind torque dynamics. This model-based approach utilizes a current-based control in place of traditional voltage-mode control and is validated using a Lyapunov-based stability analysis. The proposed scheme is compared to a linear vector controller through simulation results. These results demonstrate that the proposed controller is far more robust to wind turbulence than traditional control schemes. Full article

(This article belongs to the Special Issue Advanced Control Applications for Electrical Energy Systems)

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21 pages, 7806 KiB

Open AccessArticle

New Second-Order Sliding Mode Control Design for Load Frequency Control of a Power System

by Van Van Huynh, Phong Thanh Tran, Bui Le Ngoc Minh, Anh Tuan Tran, Dao Huy Tuan, Tam Minh Nguyen and Phan-Tu Vu

Energies 2020, 13(24), 6509; https://doi.org/10.3390/en13246509 - 9 Dec 2020

Cited by 7 | Viewed by 2252

Abstract

The implementation of the sliding mode control (SMC) for load frequency control of power networks becomes difficult due to the chattering phenomenon of high-frequency switching. This chattering problem in SMC is extremely dangerous for actuators used in power systems. In this paper, a [...] Read more.

The implementation of the sliding mode control (SMC) for load frequency control of power networks becomes difficult due to the chattering phenomenon of high-frequency switching. This chattering problem in SMC is extremely dangerous for actuators used in power systems. In this paper, a continuous control strategy by combining a second-order mode and integral siding surface is proposed as a possible solution to this problem. The proposed second-order integral sliding mode control (SOISMC) law not only rejects chattering phenomenon in control input, but also guarantees the robustness of the multi-area power network, which has an effect on parametric uncertainties such as the load variations and the matched or mismatched parameter uncertainties. Moreover, the reporting of the simulation indicates that the proposed controller upholds the quality requirement by controlling with operating conditions in the larger range, rejects disturbance, reduces the transient response of frequency, eliminates the overshoot problem, and can better address load uncertainties compared to several previous control methods. The simulation results also show that the proposed SOISMC can be used for practical multi-area power network to lessen high parameter uncertainties and load disturbances. Full article

(This article belongs to the Special Issue Advanced Control Applications for Electrical Energy Systems)

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12 pages, 11117 KiB

Open AccessArticle

Predictive Set Point Modulation Charging of Autonomous Rail Transit Vehicles

by Heng Li, Yu Zhang, Hongtao Liao and Jun Peng

Energies 2020, 13(19), 4992; https://doi.org/10.3390/en13194992 - 23 Sep 2020

Cited by 1 | Viewed by 1805

Abstract

Autonomous rail transit (ART) vehicle is a new type of urban rail transportation, which has good development prospects. It is powered by onboard supercapacitors, which are charged at midway stations. It requires short charging time and fast charging speed. Usually, multiple chargers are [...] Read more.

Autonomous rail transit (ART) vehicle is a new type of urban rail transportation, which has good development prospects. It is powered by onboard supercapacitors, which are charged at midway stations. It requires short charging time and fast charging speed. Usually, multiple chargers are used in parallel for charging. However, this will cause an overshoot phenomenon during charging, and the overshoot of multiple chargers will be superimposed on the supercapacitor, affecting the stability and life of both supercapacitors and chargers. In this paper, we propose a predictive set point modulation charging method, which can reduce the system’s overshoot and increase the reliability of the system. First, the state-space averaging method is used to establish the electronic physical model of the multicharger system. Secondly, a predictive set point modulation charging control method is designed, and the closed-loop model of the proposed charging system is developed using the buck diagram. The effectiveness of the proposed method is verified through extensive simulation and experiments. The experimental results show that compared with the classical design method, the proposed method can effectively suppress the current overshoot. Full article

(This article belongs to the Special Issue Advanced Control Applications for Electrical Energy Systems)

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17 pages, 1566 KiB

Open AccessArticle

The Antarctic Astronomical Observations Intelligent Support Equipment “Dome A” Site-Testing Observatory: Electric Power Generation and Control Systems

by Shixiong Fang, Xinyi Chen, Kanjian Zhang, Haikun Wei and Jian Ge

Energies 2020, 13(17), 4308; https://doi.org/10.3390/en13174308 - 20 Aug 2020

Cited by 2 | Viewed by 1830

Abstract

AAOISE, the Antarctic Astronomical Observations Intelligent Support Equipment, is an autonomous control equipment serving for energy support and environment thermal preservation, which is used for astronomical science observations in the Antarctic “Dome A”. It was deployed to “Dome A” and had an unattended [...] Read more.

AAOISE, the Antarctic Astronomical Observations Intelligent Support Equipment, is an autonomous control equipment serving for energy support and environment thermal preservation, which is used for astronomical science observations in the Antarctic “Dome A”. It was deployed to “Dome A” and had an unattended run until now. The AAOISE stressed on the ways to adapt to adverse circumstances of “Dome A” and to have as little influence on the environment as possible. Its shape and structure are fully qualified for transportation and thermal insulation demands. The power generation and control systems are designed to provide continuous power and heat. Its communication system can support high-reliability data transmission and communications. It offers a possibility for developing “Dome A” scientific activities and remote monitoring of the running situation of the science instruments. This paper presents a detailed description of the power generation, power control, thermal management, instrument interface, and communications systems for AAOISE. Full article

(This article belongs to the Special Issue Advanced Control Applications for Electrical Energy Systems)

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15 pages, 1202 KiB

Open AccessArticle

Adaptive Control of Four-Quadrant DC-DC Converters in Both Discontinuous and Continuous Conduction Modes

by Hicham Chaoui, Mohamad Alzayed, Okezie Okoye and Mehdy Khayamy

Energies 2020, 13(16), 4187; https://doi.org/10.3390/en13164187 - 13 Aug 2020

Cited by 3 | Viewed by 2312

Abstract

The inherently different dynamics of a DC-DC converter while operating in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) necessitate an advanced controller to control the inductor current. A conventional PI controller cannot be used across both modes since it does [...] Read more.

The inherently different dynamics of a DC-DC converter while operating in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) necessitate an advanced controller to control the inductor current. A conventional PI controller cannot be used across both modes since it does not guarantee a smooth transition between both modes. Furthermore, in time-varying input-output voltage applications of the four-quadrant converter such as in battery charging applications, the location of the boundary between the CCM and the DCM changes dynamically, creating an uncertainty. Therefore, a robust controller is required to accurately track the inductor current in the presence of uncertainties. Thus, an adaptive controller is proposed in this work, which is based on the general inverse model of the four-quadrant converter in both modes. Moreover, gain scheduling is used to switch the parameters of the controller as the converter transits between the DCM and the CCM. The adaptability and effectiveness of the controller in ensuring a smooth transition is validated by numerical simulations conducted on various converter topologies. Experimental results are also presented for a buck converter. Full article

(This article belongs to the Special Issue Advanced Control Applications for Electrical Energy Systems)

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21 pages, 1994 KiB

Open AccessArticle

Comparison of Control Strategies to Realize Synthetic Inertia in Converters

by Jürgen Marchgraber, Christian Alács, Yi Guo, Wolfgang Gawlik, Adolfo Anta, Alexander Stimmer, Martin Lenz, Manuel Froschauer and Michaela Leonhardt

Energies 2020, 13(13), 3491; https://doi.org/10.3390/en13133491 - 6 Jul 2020

Cited by 6 | Viewed by 3366

Abstract

The increasing amount of renewable energy sources in the electrical energy system leads to an increasing number of converter-based generators connected to the electrical power grid. Other than conventional power plants that are often connected to the grid via synchronous generators, converter-based generators [...] Read more.

The increasing amount of renewable energy sources in the electrical energy system leads to an increasing number of converter-based generators connected to the electrical power grid. Other than conventional power plants that are often connected to the grid via synchronous generators, converter-based generators do not provide mechanical inertia intrinsically. Therefore, ensuring frequency stability in the electrical power grid might become even more difficult in the future. With the concept of synthetic inertia, the converter-based generators partially imitate the behavior of conventional generators. By implementing such a concept in converters, they are capable of contributing to frequency stability as well. This paper compares two strategies to realize synthetic inertia by modeling converter-based generators in MATLAB/SIMULINK and simulating their behavior in a small Microgrid. The results prove that any kind of realization of synthetic inertia helps to improve frequency stability. Each of the two investigated strategies may have their scope of application in a future electrical energy system. Full article

(This article belongs to the Special Issue Advanced Control Applications for Electrical Energy Systems)

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22 pages, 9591 KiB

Open AccessArticle

Cooling Performance Optimization of Direct Dry Cooling System Based on Partition Adjustment of Axial Flow Fans

by Wenhui Huang, Lei Chen, Weijia Wang, Lijun Yang and Xiaoze Du

Energies 2020, 13(12), 3179; https://doi.org/10.3390/en13123179 - 19 Jun 2020

Cited by 7 | Viewed by 1913

Abstract

Axial flow fans play key roles in the thermo-flow performance of direct dry cooling system under windy conditions, so the energy efficiency of a power generating unit can be improved by optimizing the operation strategies of the axial flow fans. In this work, [...] Read more.

Axial flow fans play key roles in the thermo-flow performance of direct dry cooling system under windy conditions, so the energy efficiency of a power generating unit can be improved by optimizing the operation strategies of the axial flow fans. In this work, various measures based on the partition adjustment of axial flow fans with constant power consumption of a 2 × 660 MW power plant are studied by computational fluid dynamics (CFD) methods. The results show that increasing the rotational speed of the windward fans is beneficial to reduce the inlet air temperature and increase the mass flow rates of the fans, which enhance the heat rejections of the air-cooled condensers, especially at high wind speeds. Moreover, the turbine back pressures for the optimal and original cases are achieved by iterative methods, with the largest drop of 2.77 kPa at the wind speed of 12 m/s for 110-case 3 in the wind direction of −90°. It is recommended to adopt 110-case 1 and 110-case 3 at low and high wind speeds, respectively, in the wind directions of 90° and −90°, while 110-case 2 is always the best choice in the 0° wind direction. Full article

(This article belongs to the Special Issue Advanced Control Applications for Electrical Energy Systems)

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