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Sairaj V. Dhople - One of the best experts on this subject based on the ideXlab platform.

  • uncovering droop control laws embedded within the nonlinear dynamics of van der pol oscillators
    IEEE Transactions on Control of Network Systems, 2017
    Co-Authors: Mohit Sinha, Florian Dorfler, Brian Johnson, Sairaj V. Dhople
    Abstract:

    This paper examines the dynamics of power-electronic inverters in islanded microgrids that are controlled to emulate the dynamics of Van der Pol oscillators. The general strategy of controlling inverters to emulate the behavior of nonlinear oscillators presents a compelling time-domain alternative to ubiquitous droop control methods which presume the existence of a quasistationary Sinusoidal Steady State and operate on phasor quantities. We present two main results in this paper. First, by leveraging the method of periodic averaging, we demonstrate that droop laws are intrinsically embedded within a slower time scale in the nonlinear dynamics of Van der Pol oscillators. Second, we establish the global convergence of amplitude and phase dynamics in a resistive network interconnecting inverters controlled as Van der Pol oscillators. Furthermore, under a set of nonrestrictive decoupling approximations, we derive sufficient conditions for local exponential stability of desirable equilibria of the linearized amplitude and phase dynamics.

  • Synthesizing Virtual Oscillators to Control Islanded Inverters
    IEEE Transactions on Power Electronics, 2016
    Co-Authors: Brian Johnson, Mohit Sinha, Florian Dorfler, Nathan Ainsworth, Sairaj V. Dhople
    Abstract:

    Virtual oscillator control (VOC) is a decentralized control strategy for islanded microgrids where inverters are regulated to emulate the dynamics of weakly nonlinear oscillators. Compared to droop control, which is only well defined in Sinusoidal Steady State, VOC is a time-domain controller that enables interconnected inverters to stabilize arbitrary initial conditions to a synchronized Sinusoidal limit cycle. However, the nonlinear oscillators that are elemental to VOC cannot be designed with conventional linear-control design methods. We address this challenge by applying averaging- and perturbation-based nonlinear analysis methods to extract the Sinusoidal Steady-State and harmonic behavior of such oscillators. The averaged models reveal conclusive links between real- and reactive-power outputs and the terminal-voltage dynamics. Similarly, the perturbation methods aid in quantifying higher order harmonics. The resultant models are then leveraged to formulate a design procedure for VOC such that the inverter satisfies standard ac performance specifications related to voltage regulation, frequency regulation, dynamic response, and harmonic content. Experimental results for a single-phase 750 VA, 120 V laboratory prototype demonstrate the validity of the design approach. They also demonstrate that droop laws are, in fact, embedded within the equilibria of the nonlinear-oscillator dynamics. This establishes the backward compatibility of VOC in that, while acting on time-domain waveforms, it subsumes droop control in Sinusoidal Steady State.

  • uncovering droop control laws embedded within the nonlinear dynamics of van der pol oscillators
    arXiv: Systems and Control, 2014
    Co-Authors: Mohit Sinha, Florian Dorfler, Brian Johnson, Sairaj V. Dhople
    Abstract:

    This paper examines the dynamics of power-electronic inverters in islanded microgrids that are controlled to emulate the dynamics of Van der Pol oscillators. The general strategy of controlling inverters to emulate the behavior of nonlinear oscillators presents a compelling time-domain alternative to ubiquitous droop control methods which presume the existence of a quasi-stationary Sinusoidal Steady State and operate on phasor quantities. We present two main results in this work. First, by leveraging the method of periodic averaging, we demonstrate that droop laws are intrinsically embedded within a slower time scale in the nonlinear dynamics of Van der Pol oscillators. Second, we establish the global convergence of amplitude and phase dynamics in a resistive network interconnecting inverters controlled as Van der Pol oscillators. Furthermore, under a set of non-restrictive decoupling approximations, we derive sufficient conditions for local exponential stability of desirable equilibria of the linearized amplitude and phase dynamics.

Mohit Sinha - One of the best experts on this subject based on the ideXlab platform.

  • uncovering droop control laws embedded within the nonlinear dynamics of van der pol oscillators
    IEEE Transactions on Control of Network Systems, 2017
    Co-Authors: Mohit Sinha, Florian Dorfler, Brian Johnson, Sairaj V. Dhople
    Abstract:

    This paper examines the dynamics of power-electronic inverters in islanded microgrids that are controlled to emulate the dynamics of Van der Pol oscillators. The general strategy of controlling inverters to emulate the behavior of nonlinear oscillators presents a compelling time-domain alternative to ubiquitous droop control methods which presume the existence of a quasistationary Sinusoidal Steady State and operate on phasor quantities. We present two main results in this paper. First, by leveraging the method of periodic averaging, we demonstrate that droop laws are intrinsically embedded within a slower time scale in the nonlinear dynamics of Van der Pol oscillators. Second, we establish the global convergence of amplitude and phase dynamics in a resistive network interconnecting inverters controlled as Van der Pol oscillators. Furthermore, under a set of nonrestrictive decoupling approximations, we derive sufficient conditions for local exponential stability of desirable equilibria of the linearized amplitude and phase dynamics.

  • Synthesizing Virtual Oscillators to Control Islanded Inverters
    IEEE Transactions on Power Electronics, 2016
    Co-Authors: Brian Johnson, Mohit Sinha, Florian Dorfler, Nathan Ainsworth, Sairaj V. Dhople
    Abstract:

    Virtual oscillator control (VOC) is a decentralized control strategy for islanded microgrids where inverters are regulated to emulate the dynamics of weakly nonlinear oscillators. Compared to droop control, which is only well defined in Sinusoidal Steady State, VOC is a time-domain controller that enables interconnected inverters to stabilize arbitrary initial conditions to a synchronized Sinusoidal limit cycle. However, the nonlinear oscillators that are elemental to VOC cannot be designed with conventional linear-control design methods. We address this challenge by applying averaging- and perturbation-based nonlinear analysis methods to extract the Sinusoidal Steady-State and harmonic behavior of such oscillators. The averaged models reveal conclusive links between real- and reactive-power outputs and the terminal-voltage dynamics. Similarly, the perturbation methods aid in quantifying higher order harmonics. The resultant models are then leveraged to formulate a design procedure for VOC such that the inverter satisfies standard ac performance specifications related to voltage regulation, frequency regulation, dynamic response, and harmonic content. Experimental results for a single-phase 750 VA, 120 V laboratory prototype demonstrate the validity of the design approach. They also demonstrate that droop laws are, in fact, embedded within the equilibria of the nonlinear-oscillator dynamics. This establishes the backward compatibility of VOC in that, while acting on time-domain waveforms, it subsumes droop control in Sinusoidal Steady State.

  • uncovering droop control laws embedded within the nonlinear dynamics of van der pol oscillators
    arXiv: Systems and Control, 2014
    Co-Authors: Mohit Sinha, Florian Dorfler, Brian Johnson, Sairaj V. Dhople
    Abstract:

    This paper examines the dynamics of power-electronic inverters in islanded microgrids that are controlled to emulate the dynamics of Van der Pol oscillators. The general strategy of controlling inverters to emulate the behavior of nonlinear oscillators presents a compelling time-domain alternative to ubiquitous droop control methods which presume the existence of a quasi-stationary Sinusoidal Steady State and operate on phasor quantities. We present two main results in this work. First, by leveraging the method of periodic averaging, we demonstrate that droop laws are intrinsically embedded within a slower time scale in the nonlinear dynamics of Van der Pol oscillators. Second, we establish the global convergence of amplitude and phase dynamics in a resistive network interconnecting inverters controlled as Van der Pol oscillators. Furthermore, under a set of non-restrictive decoupling approximations, we derive sufficient conditions for local exponential stability of desirable equilibria of the linearized amplitude and phase dynamics.

Brian Johnson - One of the best experts on this subject based on the ideXlab platform.

  • uncovering droop control laws embedded within the nonlinear dynamics of van der pol oscillators
    IEEE Transactions on Control of Network Systems, 2017
    Co-Authors: Mohit Sinha, Florian Dorfler, Brian Johnson, Sairaj V. Dhople
    Abstract:

    This paper examines the dynamics of power-electronic inverters in islanded microgrids that are controlled to emulate the dynamics of Van der Pol oscillators. The general strategy of controlling inverters to emulate the behavior of nonlinear oscillators presents a compelling time-domain alternative to ubiquitous droop control methods which presume the existence of a quasistationary Sinusoidal Steady State and operate on phasor quantities. We present two main results in this paper. First, by leveraging the method of periodic averaging, we demonstrate that droop laws are intrinsically embedded within a slower time scale in the nonlinear dynamics of Van der Pol oscillators. Second, we establish the global convergence of amplitude and phase dynamics in a resistive network interconnecting inverters controlled as Van der Pol oscillators. Furthermore, under a set of nonrestrictive decoupling approximations, we derive sufficient conditions for local exponential stability of desirable equilibria of the linearized amplitude and phase dynamics.

  • Synthesizing Virtual Oscillators to Control Islanded Inverters
    IEEE Transactions on Power Electronics, 2016
    Co-Authors: Brian Johnson, Mohit Sinha, Florian Dorfler, Nathan Ainsworth, Sairaj V. Dhople
    Abstract:

    Virtual oscillator control (VOC) is a decentralized control strategy for islanded microgrids where inverters are regulated to emulate the dynamics of weakly nonlinear oscillators. Compared to droop control, which is only well defined in Sinusoidal Steady State, VOC is a time-domain controller that enables interconnected inverters to stabilize arbitrary initial conditions to a synchronized Sinusoidal limit cycle. However, the nonlinear oscillators that are elemental to VOC cannot be designed with conventional linear-control design methods. We address this challenge by applying averaging- and perturbation-based nonlinear analysis methods to extract the Sinusoidal Steady-State and harmonic behavior of such oscillators. The averaged models reveal conclusive links between real- and reactive-power outputs and the terminal-voltage dynamics. Similarly, the perturbation methods aid in quantifying higher order harmonics. The resultant models are then leveraged to formulate a design procedure for VOC such that the inverter satisfies standard ac performance specifications related to voltage regulation, frequency regulation, dynamic response, and harmonic content. Experimental results for a single-phase 750 VA, 120 V laboratory prototype demonstrate the validity of the design approach. They also demonstrate that droop laws are, in fact, embedded within the equilibria of the nonlinear-oscillator dynamics. This establishes the backward compatibility of VOC in that, while acting on time-domain waveforms, it subsumes droop control in Sinusoidal Steady State.

  • uncovering droop control laws embedded within the nonlinear dynamics of van der pol oscillators
    arXiv: Systems and Control, 2014
    Co-Authors: Mohit Sinha, Florian Dorfler, Brian Johnson, Sairaj V. Dhople
    Abstract:

    This paper examines the dynamics of power-electronic inverters in islanded microgrids that are controlled to emulate the dynamics of Van der Pol oscillators. The general strategy of controlling inverters to emulate the behavior of nonlinear oscillators presents a compelling time-domain alternative to ubiquitous droop control methods which presume the existence of a quasi-stationary Sinusoidal Steady State and operate on phasor quantities. We present two main results in this work. First, by leveraging the method of periodic averaging, we demonstrate that droop laws are intrinsically embedded within a slower time scale in the nonlinear dynamics of Van der Pol oscillators. Second, we establish the global convergence of amplitude and phase dynamics in a resistive network interconnecting inverters controlled as Van der Pol oscillators. Furthermore, under a set of non-restrictive decoupling approximations, we derive sufficient conditions for local exponential stability of desirable equilibria of the linearized amplitude and phase dynamics.

Florian Dorfler - One of the best experts on this subject based on the ideXlab platform.

  • uncovering droop control laws embedded within the nonlinear dynamics of van der pol oscillators
    IEEE Transactions on Control of Network Systems, 2017
    Co-Authors: Mohit Sinha, Florian Dorfler, Brian Johnson, Sairaj V. Dhople
    Abstract:

    This paper examines the dynamics of power-electronic inverters in islanded microgrids that are controlled to emulate the dynamics of Van der Pol oscillators. The general strategy of controlling inverters to emulate the behavior of nonlinear oscillators presents a compelling time-domain alternative to ubiquitous droop control methods which presume the existence of a quasistationary Sinusoidal Steady State and operate on phasor quantities. We present two main results in this paper. First, by leveraging the method of periodic averaging, we demonstrate that droop laws are intrinsically embedded within a slower time scale in the nonlinear dynamics of Van der Pol oscillators. Second, we establish the global convergence of amplitude and phase dynamics in a resistive network interconnecting inverters controlled as Van der Pol oscillators. Furthermore, under a set of nonrestrictive decoupling approximations, we derive sufficient conditions for local exponential stability of desirable equilibria of the linearized amplitude and phase dynamics.

  • Synthesizing Virtual Oscillators to Control Islanded Inverters
    IEEE Transactions on Power Electronics, 2016
    Co-Authors: Brian Johnson, Mohit Sinha, Florian Dorfler, Nathan Ainsworth, Sairaj V. Dhople
    Abstract:

    Virtual oscillator control (VOC) is a decentralized control strategy for islanded microgrids where inverters are regulated to emulate the dynamics of weakly nonlinear oscillators. Compared to droop control, which is only well defined in Sinusoidal Steady State, VOC is a time-domain controller that enables interconnected inverters to stabilize arbitrary initial conditions to a synchronized Sinusoidal limit cycle. However, the nonlinear oscillators that are elemental to VOC cannot be designed with conventional linear-control design methods. We address this challenge by applying averaging- and perturbation-based nonlinear analysis methods to extract the Sinusoidal Steady-State and harmonic behavior of such oscillators. The averaged models reveal conclusive links between real- and reactive-power outputs and the terminal-voltage dynamics. Similarly, the perturbation methods aid in quantifying higher order harmonics. The resultant models are then leveraged to formulate a design procedure for VOC such that the inverter satisfies standard ac performance specifications related to voltage regulation, frequency regulation, dynamic response, and harmonic content. Experimental results for a single-phase 750 VA, 120 V laboratory prototype demonstrate the validity of the design approach. They also demonstrate that droop laws are, in fact, embedded within the equilibria of the nonlinear-oscillator dynamics. This establishes the backward compatibility of VOC in that, while acting on time-domain waveforms, it subsumes droop control in Sinusoidal Steady State.

  • uncovering droop control laws embedded within the nonlinear dynamics of van der pol oscillators
    arXiv: Systems and Control, 2014
    Co-Authors: Mohit Sinha, Florian Dorfler, Brian Johnson, Sairaj V. Dhople
    Abstract:

    This paper examines the dynamics of power-electronic inverters in islanded microgrids that are controlled to emulate the dynamics of Van der Pol oscillators. The general strategy of controlling inverters to emulate the behavior of nonlinear oscillators presents a compelling time-domain alternative to ubiquitous droop control methods which presume the existence of a quasi-stationary Sinusoidal Steady State and operate on phasor quantities. We present two main results in this work. First, by leveraging the method of periodic averaging, we demonstrate that droop laws are intrinsically embedded within a slower time scale in the nonlinear dynamics of Van der Pol oscillators. Second, we establish the global convergence of amplitude and phase dynamics in a resistive network interconnecting inverters controlled as Van der Pol oscillators. Furthermore, under a set of non-restrictive decoupling approximations, we derive sufficient conditions for local exponential stability of desirable equilibria of the linearized amplitude and phase dynamics.

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

  • locating phase to ground short circuit faults on radial distribution lines
    IEEE Transactions on Industrial Electronics, 2007
    Co-Authors: Xinghuo Yu, M Aldabbagh, Y Wang
    Abstract:

    This paper proposes a new single phase-to-ground short-circuit fault location algorithm for overhead three-phase radial distribution lines with single-ended measurements using the Sinusoidal Steady-State analysis method. By using this approach, two Sinusoidal signals with different frequencies are first injected to the faulted line. By measuring the voltages and currents at the sending end and solving some nonlinear distributed-parameter equations, the distances and resistances of all possible fault candidates can be determined. A feature extraction method is derived to distinguish the actual fault from other pseudofault candidates. A fault locator based on the proposed approach is designed and implemented for a real-world problem. Physical model experiments and the field tests on radial distribution lines are presented to validate the proposed fault location approach

  • Fault location in power distribution networks using Sinusoidal Steady State analysis
    2004
    Co-Authors: F Han, M Al-dabbagh, Y Wang
    Abstract:

    This paper proposes a fault location method based on Sinusoidal Steady State analysis which can locate the single phase-to-ground short-circuit fault with single-ended measurement in an overhead three-phase electric power distribution lines. By measuring and calculating certain fundamental parameters of the system as well as the voltages and currents at the sending-end, which contain corresponding fault information, the location and resistance of fault candidates can be determined by solving nonlinear distributed parameter equations. Physical model experiments show that this method performs well.

  • Sinusoidal Steady-State analysis for fault location in power distribution systems
    30th Annual Conference of IEEE Industrial Electronics Society 2004. IECON 2004, 2026
    Co-Authors: F Han, Y Wang, M Al-dabbagh
    Abstract:

    This paper studies fault location with single-ended measurement when a line-to-line short-circuit fault occurs in an overhead radial three-phase distribution wire. Sinusoidal Steady State analysis based on the distributed-parameters model of the transmission wires is employed to locate a fault. By injecting two Sinusoidal excitations with different frequencies to the faulted phases, measuring the voltages and currents phasors at the sending-end of the wire and solving certain nonlinear distributed-parameter equations, the distance and resistance of fault candidates can be determined. It is shown that the one has the minimum difference between the calculated fault distances or fault resistances under the two frequencies are the most likely actual fault point. A fault locator based on the proposed scheme is designed and implemented. The parameter measurements of wires as well as the receiving-end transformers in the field are studied. Simulation on the physical model of distribution wire shows that this fault location scheme works successfully.