Sachi Jayasuriya

Simulation of a DC-DC boost converter with measurement delays

Power electronic converters are an important feature of many systems such as renewable energy systems, dc distribution systems and shipboard systems. The operations of such systems are highly reliant on their embedded communication infrastructures. Communication delays in delivering converter measurements across a computer controlled network can affect the accuracy of these measurements as viewed by remote hosts. With the preceding as motivation, this paper presents the simulation of an information embedded boost converter which observes measurement errors that result from delays in delivering the measurements. The embedded information network will be represented two ways; by a logistic growth and an exponential model. Results will concentrate on the effect of delays on the overall analysis of the converter.

Analysis of measurement delay errors in a DC-DC Buck-Boost converter using stochastic differential equations

This paper presents the use of stochastic differential equations (SDEs) to account for effects of network traffic on the communication of measurement data from a DC-DC Buck-Boost converter to a remote control center. The work is motivated by the need to account for observability of system states when a converter or system of converters is remotely monitored through a communication network comprised of switched networks. This work builds upon literature on SDEs used as appropriate tools to quantify the effects of uncertainty reflected in switched networks alone.

Nonlinear analysis of multi-converter power systems for microgrids

Multi-converter power systems play an important role in leveraging microgrids to achieve increased levels of autonomy in power system operation. Desired performance of converters associated with this type of power system architectures can be accomplished via a set of executive and distributed control strategies. However, the effectiveness of these control mechanisms is dependent on the communication network employed for information passing. Consequently, the operation of the converters as well as the power system as a whole relies on knowledge of the conditions under which the control methodologies will become obsolete. These conditions can be described by bounds for plant and network parameters such as loading level and network delay respectively. The focus of this work is the description of static and dynamic behavior of multi-converter power systems, the trajectories of which will be investigated through simulations during disturbances that will prompt the system to breach these bounds.

Effects of communication network and load parameters on information-embedded multi-converter shipboard power systems

Information-embedded multi-converter shipboard power systems are comprised of multiple independently operated converters that work together with electromechanical equipment. Their relations can produce a large variety of dynamic and static interactions that can lead to irregular behavior of a converter, a group of converters or the whole system. This inherent cross-regulation behavior may correspond to controller limit violations, which results in harmful operational situations during system disturbances. It is significant then to monitor the system during perturbations; their underlying dynamics exhibit trajectories that not only depend on their independent operation modes. Appropriate modeling is a key issue to power system analysis and warrants primary investigation. This paper addresses aspects of modeling and simulation of multi-converter based shipboard power systems with the inclusion of power electronic equipment dynamics and network control in the overall system model. The model behavior is evaluated with respect to changes in loading conditions and control parameters (local and network) and validated through simulation of a nonlinear observability formulation of the developed system model.

Observability of network-delayed multi-converter power systems

Power electronic converter systems have become a key feature of smart grid technologies due to the efforts to achieve increased levels of autonomy in power system operation. However, when devising control strategies for multi-converter power systems, nonlinearities-associated issues with these types of systems arise (e.g. bifurcations) and must be taken into account as even a slight variation of a system parameter could change the structure of the system. With the increasing need for remote control, investigation of converter system dynamics alone is insufficient. Remote control is achieved via a communication system that is used for information passing between sensors and controllers, which hence plays an important role on the overall performance of the power system. Therefore, a need arises for the study of the power system (plant) and the communication system (network) as a single entity as the performance of one is highly dependent on the other. The focus of this work is the development of a metric that will serve as an indicator of overall system status to the power system operator.

A network delay-based sensitivity analysis of information-embedded power electronic converter systems

This paper presents a sensitivity analysis study performed on an information-embedded power electronic converter system with the goal of determining the effects of network delay on its dynamics. This work is motivated by the need for enhanced monitoring schemes that can provide useful information to the power system operator that will aid in anticipating instabilities and preventing cascade failures in the event of a disturbance. In order to perform the sensitivity analysis, the nonlinear model of a buck-boost converter with proportional-integral control is linearized and then converted to modal form. A functional description of the sensitivity of eigenvalues to network delay is derived to obtain numerical results based on which the dynamics of the system modes are described.

Simulation platform development for the analysis of power electronic converter systems with plant and network coupling

Integration of multi-converter systems into information-embedded power system infrastructures has been necessitated by the increasing popularity of microgrids, renewable energy systems and DC distribution systems. This work is motivated by the need for an autonomous simulation tool to perform system-wide analysis of static and dynamic behavior of multi-converter systems taking into account the underlying coupling between the power electronic converters and electromechanical equipment as well as the power system as a whole and the communication network. When modeling and simulating power electronic converter systems, special attention must be paid to nonlinear phenomena associated with these systems. In this work, issues related to nonlinearities as well as the performance of the embedded communication network are identified; specific studies that can aid in static and dynamic analysis of these systems and the devised simulation algorithms are presented.

DC-DC boost converter with network model for photovoltaic system

Power electronic converters are an important feature of photovoltaic systems. The operations of such systems are highly reliant on their embedded communication infrastructures. Communication delays in delivering converter measurements across a computer controlled network can affect the accuracy of these measurements as viewed by remote hosts. With the preceding as motivation, this paper presents the simulation of an information embedded boost converter. The embedded information network will be represented two ways; by a logistic growth and an exponential model. Results will concentrate on the effect of delays on the overall analysis of the converter.