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Jun Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Feedback Dissipativity and Stabilization for Switched Positive Systems With a Combined Switching Law
    IEEE Transactions on Circuits and Systems II: Express Briefs, 2020
    Co-Authors: Peng Wang, Jun Zhao
    Abstract:

    The problems of feedback dissipativity and stabilization of switched positive systems are investigated via the co-design of both the combined switching strategy and the state feedback control. In particular, the proposed technique guarantees a minimal dwell time between the adjacent switching even when all subsystems are not dissipative. The time-varying multiple Linear co-positive storage functions are first adopted and sufficient conditions of rendering the considered system to be dissipative are also established. Moreover, stability is obtained when the multiple Linear Supply rates are non-positive, and asymptotic stability is further achieved under certain redesigned controller and the detectivity property of all subsystems. Finally, simulation studies verify that the proposed control scheme is valid.

  • Dissipativity of positive switched systems using multiple Linear Supply rates
    Nonlinear Analysis: Hybrid Systems, 2019
    Co-Authors: Peng Wang, Jun Zhao
    Abstract:

    Abstract In this paper, we are devoted to investigating dissipativity for a class of positive switched systems by exploiting multiple Linear copositive storage functions and multiple Linear Supply rates. A novel concept of dissipativity is presented, which depicts the overall dissipativity property of positive switched systems without the requirement of the classic dissipativity property of each positive subsystem. A sufficient condition ensuring dissipativity for positive switched systems is given under a designed switching signal. Meanwhile, L 1 gain and stability are also get based on dissipativity. Dissipativity and positivity are shown to be maintained under positive feedback interconnection, and a small-gain property is also given. All presented conditions are formulated as a Linear programming problem. Two examples are provided to illustrate the effectiveness of the main results.

  • Dissipativity of Switched Positive Systems via State-Dependent Switching with Dwell Time
    2018 37th Chinese Control Conference (CCC), 2018
    Co-Authors: Peng Wang, Caiyun Wu, Jun Zhao
    Abstract:

    In this paper, we study dissipativity for a class of switched positive systems by exploiting multiple Linear copositive storage functions and multiple Linear Supply rates without the requirement of the classic dissipativity property of positive subsystems. A state-dependent and time driven switching law is presented, which is different from traditional dwell time-switching and state-switching. Then, a sufficient condition guaranteeing dissipativity under the positivity constraint are obtained. And the sufficient condition can be easily examined in terms of Linear programming. Finally, a numerical example is provided to illustrate the performance of the proposed strategy.

Zoya Popovic - One of the best experts on this subject based on the ideXlab platform.

  • Efficient Linear Supply-modulated PA with harmonic injection
    2013
    Co-Authors: Asmita Dani, Mike Coffey, Zoya Popovic
    Abstract:

    This paper discusses the concept of partial Supply modulation with harmonic injection at the output of a PA, resulting in constant high efficiency and Linearity over a wide range of output power levels. NonLinear simulations for the TriQuint TGF2023-01 6-W GaN device are validated with a proof-of-concept PA biased in class-AB mode at 2.45 GHz. Efficiencies in the range of 62-76% are achieved for a ≤ 7 dB variation in the output power. The corresponding range of drain voltage is 10-27V and injected harmonic power range is -33 to -10 dBc w.r.t. fundamental output power. This high efficiency amplifier simultaneously achieves high Linearity. Simulated and measured third harmonic shows a ≥ 15 dB reduction as compared to a PA with no harmonic injection. It is also shown that simulated two-tone IMD3 follow a similar trend.

  • Codesign of PA, Supply, and Signal Processing for Linear Supply-Modulated RF Transmitters
    IEEE Transactions on Microwave Theory and Techniques, 2012
    Co-Authors: J. Hoversten, Scott Schafer, Michael Roberg, Mark A. Norris, Dragan Maksimovic, Zoya Popovic
    Abstract:

    This paper presents a method for achieving high-efficiency Linear transmitters by codesign of the RF power amplifier (PA), dynamic Supply, and signal processing. For varying amplitude signals, the average efficiency of the PA is improved by adding a Supply modulator with requirements derived from nonstandard PA modeling. The efficient PA and Supply modulator both introduce signal distortion. A targeted Linearization procedure is demonstrated with reduced complexity compared to standard digital predistortion. Experimental results on a 2.14-GHz 81% efficient 40-W peak power GaN PA illustrate the codesign method by achieving 52.5% composite power-added efficiency with high Linearity for a W-CDMA signal with a 23-MHz Supply modulator bandwidth.

  • System considerations for efficient and Linear Supply modulated RF transmitters
    2010 IEEE 12th Workshop on Control and Modeling for Power Electronics (COMPEL), 2010
    Co-Authors: John Hoversten, Zoya Popovic
    Abstract:

    This paper presents an overview of the envelope tracking RF transmitters which require a dynamic power Supply implemented as an envelope modulator. Optimal design of this component requires an understanding of the system and power amplifier (PA) behavior. Here, we specifically address design of transmitters for wireless communications at the base station in the 2.14 GHz band with W-CDMA modulation. PA characterization and a new system modeling method are developed to determine envelope modulator requirements for a given signal type. System measurements of a proof-of-concept ET system dissipates 61% less power than the traditional drive-modulated transmitter.

Peng Wang - One of the best experts on this subject based on the ideXlab platform.

  • Feedback Dissipativity and Stabilization for Switched Positive Systems With a Combined Switching Law
    IEEE Transactions on Circuits and Systems II: Express Briefs, 2020
    Co-Authors: Peng Wang, Jun Zhao
    Abstract:

    The problems of feedback dissipativity and stabilization of switched positive systems are investigated via the co-design of both the combined switching strategy and the state feedback control. In particular, the proposed technique guarantees a minimal dwell time between the adjacent switching even when all subsystems are not dissipative. The time-varying multiple Linear co-positive storage functions are first adopted and sufficient conditions of rendering the considered system to be dissipative are also established. Moreover, stability is obtained when the multiple Linear Supply rates are non-positive, and asymptotic stability is further achieved under certain redesigned controller and the detectivity property of all subsystems. Finally, simulation studies verify that the proposed control scheme is valid.

  • Dissipativity of positive switched systems using multiple Linear Supply rates
    Nonlinear Analysis: Hybrid Systems, 2019
    Co-Authors: Peng Wang, Jun Zhao
    Abstract:

    Abstract In this paper, we are devoted to investigating dissipativity for a class of positive switched systems by exploiting multiple Linear copositive storage functions and multiple Linear Supply rates. A novel concept of dissipativity is presented, which depicts the overall dissipativity property of positive switched systems without the requirement of the classic dissipativity property of each positive subsystem. A sufficient condition ensuring dissipativity for positive switched systems is given under a designed switching signal. Meanwhile, L 1 gain and stability are also get based on dissipativity. Dissipativity and positivity are shown to be maintained under positive feedback interconnection, and a small-gain property is also given. All presented conditions are formulated as a Linear programming problem. Two examples are provided to illustrate the effectiveness of the main results.

  • Dissipativity of Switched Positive Systems via State-Dependent Switching with Dwell Time
    2018 37th Chinese Control Conference (CCC), 2018
    Co-Authors: Peng Wang, Caiyun Wu, Jun Zhao
    Abstract:

    In this paper, we study dissipativity for a class of switched positive systems by exploiting multiple Linear copositive storage functions and multiple Linear Supply rates without the requirement of the classic dissipativity property of positive subsystems. A state-dependent and time driven switching law is presented, which is different from traditional dwell time-switching and state-switching. Then, a sufficient condition guaranteeing dissipativity under the positivity constraint are obtained. And the sufficient condition can be easily examined in terms of Linear programming. Finally, a numerical example is provided to illustrate the performance of the proposed strategy.

Keith R. Godfrey - One of the best experts on this subject based on the ideXlab platform.

  • parameterization of Linear Supply functions in nonLinear ac electricity market equilibrium models part i literature review and equilibrium algorithm
    IEEE Transactions on Power Systems, 2013
    Co-Authors: Andreas G. Petoussis, Xiao-ping Zhang, Savvas G. Petoussis, Keith R. Godfrey
    Abstract:

    The Linear Supply function equilibrium (SFE) model can be used to investigate bid-based electricity pool markets. Several studies assume that the market players construct optimal strategic bids by parameterizing the Linear marginal cost function of their generating units. Four different types of parameterization are possible, for which the slope and/or the intercept of the marginal cost functions are varied. This paper reviews the existing literature and proposes a primal-dual nonLinear interior point algorithm to solve a bi-level market problem with AC network representation, using any of the parameterization methods. Part II of this paper uses the proposed algorithm to examine the effects of the different parameterizations on the resulting SFE solutions, the role of network complexity and the nature of the equilibrium points.

  • Parameterization of Linear Supply functions in nonLinear AC electricity market equilibrium models - Part II: Case studies
    IEEE Transactions on Power Systems, 2013
    Co-Authors: Andreas G. Petoussis, Xiao-ping Zhang, Savvas G. Petoussis, Keith R. Godfrey
    Abstract:

    This study utilizes the primal-dual nonLinear interior point algorithm formulated in Part I of this two-series paper, to obtain electricity market Supply function equilibrium solutions for the bi-level market problem of nonLinear power systems with AC meshed networks. The strategic offers of the market players are modeled by parameterizing the generation marginal cost functions using any of the four available parameterization methods to obtain profit-maximizing Linear Supply function bids. The analysis takes into account a variety of test systems and examines the relation between the equilibrium solutions obtained from the different parameterization methods and the role of network complexity. An analysis of multiple equilibria in AC network constrained systems is also provided.

  • Parameterization of Linear Supply Functions in NonLinear AC Electricity Market Equilibrium Models—Part I: Literature Review and Equilibrium Algorithm
    IEEE Transactions on Power Systems, 2013
    Co-Authors: Andreas G. Petoussis, Xiao-ping Zhang, Savvas G. Petoussis, Keith R. Godfrey
    Abstract:

    The Linear Supply function equilibrium (SFE) model can be used to investigate bid-based electricity pool markets. Several studies assume that the market players construct optimal strategic bids by parameterizing the Linear marginal cost function of their generating units. Four different types of parameterization are possible, for which the slope and/or the intercept of the marginal cost functions are varied. This paper reviews the existing literature and proposes a primal-dual nonLinear interior point algorithm to solve a bi-level market problem with AC network representation, using any of the parameterization methods. Part II of this paper uses the proposed algorithm to examine the effects of the different parameterizations on the resulting SFE solutions, the role of network complexity and the nature of the equilibrium points.

Ashkan Rahimi-kian - One of the best experts on this subject based on the ideXlab platform.

  • A Dynamic Risk-Constrained Bidding Strategy for Generation Companies Based on Linear Supply Function Model
    IEEE Systems Journal, 2015
    Co-Authors: Bananeh Ansari, Ashkan Rahimi-kian
    Abstract:

    A risk-constrained bidding model for generation companies (GenCos) competing in a pool-based electricity market is presented in this paper. In the proposed model, it is assumed that GenCos submit Linear Supply functions to the market operator. The intercept of the Supply function is the decision variable to be optimized during the strategic bidding process by the GenCo. The model takes into account the uncertainties in system demand and uses mean-variance portfolio theory to assess and manage the players' risk. Moreover, electricity market dynamics are modeled assuming boundedly rational GenCos. The strategic bidding process is then formulated as an optimal control problem and solved using a dynamic programming algorithm. A real-time adaptive feedback is also added to the bidding model to manage the congestion situations. Finally, the proposed bidding scheme is applied to two different case studies, and the simulated results are analyzed and compared with those in some similar research studies.