Engineering Commons^™

A New Single-Phase Single-Stage Ac-Dc Stacked Flyback Converter With Active Clamp Zvs, Yuntong Li

Electronic Thesis and Dissertation Repository

Single-stage AC-DC converters integrate an AC-DC front-end converter with a DC-DC back-end converter. Compared with conventional two-stage AC-DC converters, single-stage AC-DC converters use less components and only one controller, which is used to regulate the output voltage. As a result, the cost, size and complexity of AC-DC converters can be reduced, but single-stage converters do not perform as well as two-stage converters, and most have drawbacks that are related to the fact that the DC bus voltage is not controlled an can become excessive.

A new single-phase single-stage AC-DC converter that uses stacked flyback converters is proposed in this thesis. …

A Novel Ac-Dc Interleaved Zcs-Pwm Boost Converter, Ramtin Rasoulinezhad

Electronic Thesis and Dissertation Repository

AC-DC converters with input power factor correction (PFC) that consist of two or more interleaved boost converter modules are popular in industry. PFC is a must in today’s AC-DC converters as their input current must meet harmonic standards set by regulatory agencies. With interleaving, the input current of each module can make to be discontinuous and the size of their input inductors since interleaving can reduce the high ripple in each module and produce a net input current with a ripple that is comparable to that achieved with a single boost converter module with a large input inductor.

In high- …

A Comparison Between Different Snubbers For Flyback Converters, Adel Alganidi

Electronic Thesis and Dissertation Repository

The DC-DC flyback power converter is widely used in low power commercial and industrial applications ( > 150 W) such as in computers, telecom, consumer electronics because it is one of the simplest and least expensive converter topologies with transformer isolation. Its main power circuit consists of just a semiconductor device like a MOSFET operating as a switch, a transformer, an output diode and an output filter capacitor. The converter switch, however, is susceptible to high voltage spikes due to the interaction between its output capacitance and the leakage inductance of the transformer. These spikes can exceed the ratings of the …

Novel Night And Day Control Of A Pv Solar System As A Statcom (Pv-Statcom) For Damping Of Power Oscillations, Hesamaldin Maleki

Electronic Thesis and Dissertation Repository

Installations of large scale PV solar farms are rapidly increasing, worldwide. This is causing a growing apprehension that inertialess power injections from these inverter based generators will result in a decline in power system stability. Instead, this thesis presents novel applications of a patent pending technology whereby the PV solar farms actually help significantly increase system stability. A novel 24/7 (night and day) control of a large-scale PV solar farm as a dynamic reactive power compensator STATCOM, termed PV-STATCOM, is presented for damping low-frequency electromechanical power oscillations resulting in a significant improvement in power transfer capability of existing power transmission …

Fault Location In High Voltage Shunt Capacitor Banks, Hessamoddin Jouybari Moghaddam

Electronic Thesis and Dissertation Repository

High Voltage Shunt Capacitor Banks (HV-SCBs) are critical substation assets that are primarily used to improve power factor and thus power transmission capability. Over temperature, over voltages, manufacturing defects can cause internal failures of capacitor elements. With today’s sensitive protection available in numerical relays these failures will be detected and SCBs will be taken out of service. But determining the phase and section in which capacitor elements have failed is important for utilities to decrease downtime of SCBs. This thesis proposes methods to address the challenges in fault location of SCBs. The proposed methods apply calibrating factors that compensate for …

Predictive Energy Management Of Islanded Microgrids With Photovoltaics And Energy Storage, Dennis G. Michaelson

Electronic Thesis and Dissertation Repository

Islanded microgrids powered primarily by photovoltaic (PV) arrays present a challenging control problem due to the intermittent production and the relatively close scale between the sources and the loads. Energy storage in such microgrids plays an important role in balancing supply with demand, and in extending operation during periods when the PV supply is not available or insufficient. The efficient operation of such microgrids requires effective management of all resources. A predictive energy management strategy can potentially avoid or effectively mitigate upcoming outages. This thesis presents an energy management system (EMS) for such microgrids. The EMS uses a predictive approach …