DC bus voltage regulation in the presence of constant power load using sliding mode controlled dc-dc Bi-directional converter interfaced storage unit
07 Jun 2015-pp 257-262
TL;DR: A robust sliding mode controller for a dc/dc, bidirectional converter interfacing storage unit to ensure dc bus voltage regulation in a stand-alone dc microgrid is presented in this paper.
Abstract: The paper presents a robust sliding mode controller for a dc/dc, bidirectional converter interfacing storage unit to ensure dc bus voltage regulation in a stand-alone dc microgrid. The dc bus supplies a combination of a constant power load and conventional resistive load. In order to enhance the battery life, a state-of-charge based charging algorithm is also implemented. Depending on the measured dc bus voltage, the controller selects the appropriate operating mode of the converter. The effectiveness of the proposed controller has been validated through simulation results.
Citations
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TL;DR: A comprehensive review is presented on accomplished research work on stabilization of dc and ac microgrid system stabilization techniques, which can basically be classified as compensation done at feeder side; by adding intermediate circuitry; and at load side.
Abstract: Microgrid, because of its advantages over conventional utility grids, is a prudent approach to implement renewable resource-based electricity generation. Despite its advantages, microgrid has to operate with a significant proportion of constant power loads that exhibit negative incremental impedance and thus cause serious instability in the system. In this paper, a comprehensive review is presented on accomplished research work on stabilization of dc and ac microgrid. After reviewing these, microgrid system stabilization techniques are classified with required discussions. As found out in this paper, the stabilization techniques can basically be classified as compensation done: 1) at feeder side; 2) by adding intermediate circuitry; and 3) at load side. Finally, after analyzing the merits and drawbacks of each generalized technique, several infographics are presented to highlight the key findings of this paper.
82 citations
Cites background from "DC bus voltage regulation in the pr..."
...[30] adopted a novel sliding mode controller and presented appreciable results....
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TL;DR: A composite prescribed performance control strategy is developed for stabilizing dc/dc boost converter feeding constant power loads by employing the exact feedback linearization technique and the composite nonlinear controller with prescribed performance is determined.
Abstract: In this paper, a composite prescribed performance control strategy is developed for stabilizing dc/dc boost converter feeding constant power loads. First, by employing the exact feedback linearization technique, the nonlinear uncertain dc converter system is first transformed into the Brunovsky’s canonical form. Then, a nonlinear disturbance observer is utilized to evaluate the dynamic change of load power and the accuracy of output voltage regulated by feedforward compensation. Next, the prescribed performance controller is elaborately designed to ensure that the tracking error of output voltage is always within the margin of predefined error bounds. Based on the backstepping design approach, the composite nonlinear controller with prescribed performance is determined. Finally, the numerical simulation results are presented to demonstrate the tracking performance of the proposed controller.
43 citations
Cites methods from "DC bus voltage regulation in the pr..."
...In many existing literatures, such as [23]–[27], the sliding mode control (SMC) approach and its update composite control law are utilized for stabilizing dc/dc converter....
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TL;DR: In this article, a sliding mode controller is developed for a microgrid system in the presence of constant power loads to assure a certain control objective of keeping the output voltage constant at 480 V.
Abstract: To implement renewable energy resources, microgrid systems have been adopted and developed into the technology of choice to assure mass electrification in the next decade Microgrid systems have a number of advantages over conventional utility grid systems, however, they face severe instability issues due to the continually increasing constant power loads To improve the stability of the entire system, the load side compensation technique is chosen because of its robustness and cost effectiveness In this particular occasion, a sliding mode controller is developed for a microgrid system in the presence of constant power loads to assure a certain control objective of keeping the output voltage constant at 480 V After that, a robustness analysis of the sliding mode controller against parametric uncertainties was performed and the sliding mode controller’s robustness against parametric uncertainties, frequency variations, and additive white Gaussian noise (AWGN) are presented Later, the performance of the proportional integral derivative (PID) and sliding mode controller are compared in the case of nonlinearity, parameter uncertainties, and noise rejection to justify the selection of the sliding mode controller over the PID controller All the necessary calculations are reckoned mathematically and results are verified in a virtual platform such as MATLAB/Simulink with a positive outcome
30 citations
Cites methods from "DC bus voltage regulation in the pr..."
...have presented a robust sliding mode control technique to investigate CPL instability [19]....
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TL;DR: In this paper, a storage based load side compensation technique is used to enhance stability of micro-grids, and two nonlinear control techniques, Sliding Mode Controller (SMC) and Lyapunov Redesign Controller (LRC), are individually implemented to control microgrid system stability with desired robustness.
Abstract: To mitigate the microgrid instability despite the presence of dense Constant Power Load (CPL) loads in the system, a number of compensation techniques have already been gone through extensive research, proposed, and implemented around the world. In this paper, a storage based load side compensation technique is used to enhance stability of microgrids. Besides adopting this technique here, Sliding Mode Controller (SMC) and Lyapunov Redesign Controller (LRC), two of the most prominent nonlinear control techniques, are individually implemented to control microgrid system stability with desired robustness. CPL power is then varied to compare robustness of these two control techniques. This investigation revealed the better performance of the LRC system compared to SMC to retain stability in microgrid with dense CPL load. All the necessary results are simulated in Matlab/Simulink platform for authentic verification. Reasons behind inferior SMC performance and ways to mitigate that are also discussed. Finally, the effectiveness of SMC and LRC systems to attain stability in real microgrids is verified by numerical analysis.
29 citations
Cites background from "DC bus voltage regulation in the pr..."
...demonstrated, in [23], a robust sliding mode control technique to examine CPL instability....
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TL;DR: In this article, a Lyapunov redesign controller is proposed to improve the microgrid stability in the presence of constant power loads by adopting storage system based load side compensation technique.
16 citations
References
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TL;DR: A tutorial account of variable structure control with sliding mode is presented, introducing in a concise manner the fundamental theory, main results, and practical applications of this powerful control system design approach.
Abstract: A tutorial account of variable structure control with sliding mode is presented. The purpose is to introduce in a concise manner the fundamental theory, main results, and practical applications of this powerful control system design approach. This approach is particularly attractive for the control of nonlinear systems. Prominent characteristics such as invariance, robustness, order reduction, and control chattering are discussed in detail. Methods for coping with chattering are presented. Both linear and nonlinear systems are considered. Future research areas are suggested and an extensive list of references is included. >
2,884 citations
"DC bus voltage regulation in the pr..." refers background or methods in this paper
...The chosen reaching dynamics defining the evolution of the switching function is given by [18],...
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...The existence of the sliding mode for the proposed PWM based sliding-mode controllers of (10)-(12) is proved based on the reaching dynamics proposed in [18]....
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TL;DR: Sliding-mode and feedback linearization techniques along with large-signal phase plane analysis are presented as methods to analyze, control, and stabilize automotive converters/systems operating with CPLs.
Abstract: Power electronic converters and electric motor drives are being put into use at an increasingly rapid rate in advanced automobiles. However, the new advanced automotive electrical systems employ multivoltage level hybrid ac and dc as well as electromechanical systems that have unique characteristics, dynamics, and stability problems that are not well understood due to the nonlinearity and time dependency of converters and because of their constant power characteristics. The purpose of this paper is to present an assessment of the negative impedance instability concept of the constant power loads (CPLs) in automotive power systems. The main focus of this paper is to analyze and propose design criteria of controllers for automotive converters/systems operating with CPLs. The proposed method is to devise a new comprehensive approach to the applications of power electronic converters and motor drives in advanced automotive systems. Sliding-mode and feedback linearization techniques along with large-signal phase plane analysis are presented as methods to analyze, control, and stabilize automotive converters/systems with CPLs
813 citations
"DC bus voltage regulation in the pr..." refers background in this paper
...For more information on CPLs and their effects in dc systems, readers are advised to see reference [1]....
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TL;DR: In this article, a distributed control strategy based on improved dc bus signaling is proposed for a modular photovoltaic (PV) generation system with battery energy storage elements, which is composed of three modular dc/dc converters for PV arrays, two grid-connected dc/ac converters, and one DC/dc converter for battery charging/discharging and local loads, which are available of either gridconnected operation or islanding operation.
Abstract: Modular generation system, which consists of modular power conditioning converters, is an effective solution to integrate renewable energy sources with conventional utility grid to improve reliability and efficiency, especially for photovoltaic generation. A distributed control strategy based on improved dc bus signaling is proposed for a modular photovoltaic (PV) generation system with battery energy storage elements. In this paper, the modular PV generation system is composed of three modular dc/dc converters for PV arrays, two grid-connected dc/ac converters, and one dc/dc converter for battery charging/discharging and local loads, which is available of either grid-connected operation or islanding operation. By using the proposed control strategy, the operations of a modular PV generation system are categorized into four modes: islanding with battery discharging, grid-connected rectification, grid-connected inversion, and islanding with constant voltage (CV) generation. The power balance of the system under extreme conditions such as the islanding operation with a full-charged battery is taken into account in this control strategy. The dc bus voltage level is employed as an information carrier to distinguish different modes and determine mode switching. Control methods of modular dc/dc converters, battery converter, and grid-connected converter are addressed. An autonomous control method for modular dc/dc converters is proposed to realize smooth switching between CV operation and maximum power point tracking operation, which enables the dc bus voltage regulation capability of modular dc/dc converters. Seamless switching of a battery converter between charging and discharging and that of a grid-connected converter between rectification and inversion are ensured by the proposed control methods. Experiments verify the practical feasibility and the effectiveness of the proposed control strategies.
585 citations
TL;DR: In this paper, the authors investigated the control and operation of a dc microgrid, which can be operated at grid connected or island modes, and proposed a coordinated strategy for the battery system, wind turbine, and load management.
Abstract: Control and operation of a dc microgrid, which can be operated at grid connected or island modes, are investigated in this paper. The dc microgrid consists of a wind turbine, a battery energy storage system, dc loads, and a grid-connected converter system. When the system is grid connected, active power is balanced through the grid supply during normal operation to ensure a constant dc voltage. Automatic power balancing during a grid ac fault is achieved by coordinating the battery energy storage system and the grid converter. To ensure that the system can operate under island conditions, a coordinated strategy for the battery system, wind turbine, and load management, including load shedding, are proposed. PSCAD/EMTDC simulations are presented to demonstrate the robust operation performance and to validate the proposed control system during various operating conditions, such as variations of wind power generation and load, grid ac faults, and islanding.
543 citations
TL;DR: This paper explains the control structure required for the converters to permit the use of DBS, and explains a procedure for implementing a system-wide control law through independent control of the source/storage interface converters.
Abstract: A dc nanogrid is a hybrid renewable system since renewable sources supply the average load demand, while storage and nonrenewable generation maintain the power balance in the presence of the stochastic renewable sources. The system is power electronic based, with converters being used to interface both the sources and loads to the system. The nanogrid is controlled using dc-bus signaling (DBS), a distributed control strategy in which the control nodes, the source/storage interface converters, induce voltage-level changes to communicate with the other control nodes. This paper explains the control structure required for the converters to permit the use of DBS, and explains a procedure for implementing a system-wide control law through independent control of the source/storage interface converters. Experimental results are presented to demonstrate the operation of this novel control strategy
538 citations
"DC bus voltage regulation in the pr..." refers background in this paper
...DC bus voltage signaling based approach to implement power management in a dc power system is extensively used in the literature, wherein measured dc bus voltage governs the operating mode of sources/loads to maintain the power balance in the dc power system [12]–[15]....
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