Thomas H. Ortmeyer

Bio: Thomas H. Ortmeyer is an academic researcher from Clarkson University. The author has contributed to research in topics: Harmonic & Electric power system. The author has an hindex of 10, co-authored 33 publications receiving 550 citations.

Evaluation of neural network based real time maximum power tracking controller for PV system

Abstract: This paper presents a neural network based maximum power tracking controller for interconnected PV power systems The neural network is utilized to identify the optimal operating voltage of the PV power system The controller generates the control signal in real-time, and the control signal is fed back to the voltage control loop of the inverter to shift the terminal voltage of the PV power system to its identified optimum, which yields maximum power generation The controller is of the PI type The proportional and the integral gains are set to their optimal values to achieve fast response and also to prevent overshoot and also undershoot Continuous measurement is required for the open circuit voltage on the monitoring cell, and also for the terminal voltage of the PV power system Because of the accurate identification of the optimal operating voltage of the PV power system, more than 99% power is drawn from the actual maximum power >

The Effects of Power System Harmonics on Power System Equipment and Loads

Abstract: This report is intended to present a summary of current knowledge regarding the effects of power system harmonics on system equipment and loads. The purpose of this summary is two-fold: first, to lay a groundwork for the study and control of system harmonics; and second, to promote a discussion with those closely involved with each of the various load types.

A Risk-Based Optimization Model for Electric Vehicle Infrastructure Response to Cyber Attacks

Abstract: Security of the smart grid is at risk when the vulnerabilities of the electric vehicle (EV) infrastructure is not addressed properly As vehicles are becoming smarter and connected, their risk of being compromised is increasing On various occasions and venues, hacking into smart or autonomous vehicles have been shown to be possible For most of the time, a compromised vehicle poses a threat to the driver and other vehicles On the other hand, when the vehicle is electric, the attack may spread to the power grid infrastructure starting from the EV supply equipment (EVSE) all the way up to the utility systems Traditional isolation-based protection schemes do not work well in smart grid since electricity services have availability constraints and few of the components have physical backups In this paper, we propose a mixed integer linear programming model that jointly optimizes security risk and equipment availability in the interdependent power and EV infrastructure We adopt an epidemic attack model to mimic malware propagation We assume malware spreads during EV charging when an EV is charged from an infected EVSE and then travels and recharges at another EVSE In addition, it spreads through the communication network of EVSEs The proposed response model aims to isolate a subset of compromised and likely compromised EVSEs The response model minimizes the risk of attack propagation while providing a satisfactory level of equipment availability to supply demand Our analysis shows the theoretical and practical bounds for the proposed response model in smart grid in the face of attacks to the EV infrastructure

Distribution System Harmonic Filter Planning

Abstract: A planning methodology for distribution system harmonic filtering is proposed. The method is intended for use on radial distribution systems with no large harmonic sources. It is proposed that 60 hertz VAr planning be done first to allocate the VAr resources. Following this process, the harmonic filter planning can be readily accomplished. Characteristics of the distribution systems and the harmonic sources are exploited to provide a practical filter planning technique which is effective and efficient.

Distribution system modeling with distributed harmonic sources

Abstract: A method of analyzing distribution-system harmonic levels caused by distributed harmonic sources along feeders is proposed and investigated Feeder and voltage predictions were compared with the actual measurements, with good results The proposed feeder models are used to form a distribution-system model capable of studying capacitor switching and sensitivity analysis Switching studies on one system successfully predicted the change in voltage level due to the removal of capacitance The results indicate that the method can be used to complement harmonic measurements to minimize the measurement requirements and to provide insight into the harmonic propagation It is concluded that the proposed method yields reasonable accuracy while minimizing data requirements and computational effort >

Introduction to Fuzzy Logic using MATLAB

Abstract: Classical Sets and Fuzzy Sets.- Classical and Fuzzy Relations.- Membership Functions.- Defuzzification.- Fuzzy Rule-Based System.- Fuzzy Decision Making.- Applications of Fuzzy Logic.- Fuzzy Logic Projects with Matlab.

Closure on "Theoretical and experimental analyses of photovoltaic systems with voltage and current-based maximum power point tracking"

Abstract: Detailed theoretical and experimental analyses are presented for the comparison of two simple fast and reliable maximum power point tracking (MPPT) techniques for photovoltaic systems (PV): the voltage-based (VMPPT) and the current-based (CMPPT) approaches. A microprocessor-controlled tracker capable of online voltage and current measurements and programmed with both VMPPT and CMPPT algorithms is constructed. The load of the solar system is either a water pump or a resistance. Simulink facilities are used for simulation and modeling of the novel trackers. The main advantage of this new MPPT, as compared with present trackers, is the elimination of reference (dummy) cells, which results in a more efficient, less expensive, and more reliable PV system.

Novel maximum-power-point-tracking controller for photovoltaic energy conversion system

Abstract: A novel maximum-power-point-tracking (MPPT) controller for a photovoltaic (PV) energy conversion system is presented. Using the slope of power versus voltage of a PV array, the proposed MPPT controller allows the conversion system to track the maximum power point very rapidly. As opposed to conventional two-stage designs, a single-stage configuration is implemented, resulting in size and weight reduction and increased efficiency. The proposed system acts as a solar generator on sunny days, in addition to working as an active power line conditioner on rainy days. Finally, computer simulations and experimental results demonstrate the superior performance of the proposed technique.

Reliability Issues in Photovoltaic Power Processing Systems

Abstract: Power processing systems will be a key factor of future photovoltaic (PV) applications. They will play a central role in transferring, to the load and/or to the grid, the electric power produced by the high-efficiency PV cells of the next generation. In order to come up the expectations related to the use of solar energy for producing electrical energy, such systems must ensure high efficiency, modularity, and, particularly, high reliability. The goal of this paper is to provide an overview of the open problems related to PV power processing systems and to focus the attention of researchers and industries on present and future challenges in this field.