Variable Frequency Controlled Zero-Voltage Switching Single-Ended Current-fed DC-to-AC Converter with Output Isolation

A modified DC-to-AC power converter accomplishes power transfer to a load with electrical isolation, zero-voltage and zero-current switching, using a transformer core resetting mechanism. The power converter contains two switching devices, a main device connected in parallel and a secondary device connected in series with a transformer primary winding. A secondary winding of the transformer is connected through a two-port resonant link circuit to a resistive load. Zero-voltage switching and proper transformer-core resetting are achieved from the resonance that exists between the parasitic capacitance of the secondary switching device and the magnetization inductance of the transformer. A transformer leakage inductance facilitates zero-current switching; thus, reducing the turn-on switching loss in the conventional main switching device. The switching converter contains a lossless clamping circuit, to limit the voltage stresses across both of the power switching devices to the reflecte

Power Converter Possessing Zero-Voltage Switching and Output Isolation

A modified boost converter accomplishes power transfer to a load with an electrical isolation, a zero-voltage and a zero-current switching, a transformer core resetting mechanism, and component stresses identical to those in the conventional boost converters. The power converter contains two switching devices, a main one connected in parallel and a secondary one connected in series with a transformer primary winding. A secondary winding of the transformer is connected through an output rectifier to the load. Zero-voltage switching and proper transformer-core resetting are achieved from the resonance that exists between the parasitic capacitance of the secondary switching device and the magnetization inductance of the transformer. A transformer leakage inductance facilitates zero-current switching; thus, reducing the recovery time and current in the output rectifier, and the turn-on switching loss in the conventional main switching device. The switching converter contains a lossless cl

AC-DC Converter with Power Factor Correction (PFC).

One-stage power factor correction (PFC) with output electrical isolation. Two types of PFC converters are proposed here: 1) Multi stage capacitive-switching network low voltage PFC converter and 2) two-switch soft switching PFC converters. This resulted in a near unity power factor AC-DC converter with low voltage output. The second converter uses the power switch in combination with a grounded auxiliary switch to produce soft-switching converter to operate in high switching frequencies. Due to its simplified power stage and control circuit, this converter presents a variety of benefits including better efficiency (87%), lower costs, higher reliability, increased operating frequencies into the hundreds of kilo-hertz range and low operating voltages of less than 5 volts. With PSPICE simulation and experimental results,a measured power factor of 0.99 was obtained by the single switch converter

Coin Disks

A floppy disk cartridge adapter having a removable coin shaped memory disk. The 3 & 1/2 inch size cartridge adapter can fit into conventional personal computer disk drives. The small coin shaped magnetic disk has a diameter of approximately 1 inch, and can be easily snapped into and removed from the cartridge adapter. The coin disk fits on a spindle that is side by side to the floating drive plate used in regular 3 & 1/2 inch floppy diskettes. The spindle can be attached by various drive systems to rotate simultaneously with the rotating drive plate. One version is belt driven, another has the coin disk snap onto a spindle supported wheel whose sides frictionally rub against the drive plate wheel, and a third version has the coin disk snap onto the spindle supported gear wheel whose sides contain teeth which mateably engage like side teeth on the drive plate wheel. The coin disk can be alternatively inserted into a separate casing having a spring loaded shutter so that the conventional disk drive being used can access the magnetic sides of the coin disk by sliding the shutter. When removed from the cartridge adapater, the disk can be instered into a small clip retainer..

Variable Frequency Iteration MPPT for Resonant Power Converters

A method of maximum power point tracking (MPPT) uses an MPPT algorithm to determine a switching frequency for a resonant power converter, including initializing by setting an initial boundary frequency range that is divided into initial frequency sub-ranges bounded by initial frequencies including an initial center frequency and first and second initial bounding frequencies. A first iteration includes measuring initial powers at the initial frequencies to determine a maximum power initial frequency that is used to set a first reduced frequency search range centered or bounded by the maximum power initial frequency including at least a first additional bounding frequency. A second iteration includes calculating first and second center frequencies by averaging adjacent frequent values in the first reduced frequency search range and measuring second power values at the first and second center frequencies. The switching frequency is determined from measured power values including the second power values

DC-DC Converter with Coupled-Inductors Current-doubler

A coupled-inductor current-doubler topology for a power converter has first and second rectifiers and first and second coupled inductors. Each coupled indicator has a main inductor inductively coupled with a secondary inductor. The secondary inductor of the first coupled inductor is coupled in series with one of the first and second rectifiers and the secondary inductor of the second coupled inductor coupled in series with the other one of the first and second rectifiers

PWM Half-Bridge Converter with Dual-Equally Adjustable Control Signal Dead-Time

A method and system of controlling half-bridge DC--DC converters to achieve Zero Voltage Switching (ZVS) for at least one of the switches. The soft-switching half-bridge DC--DC converter system includes soft-switching for all switches by adding an additional branch with a switch and a diode across the primary side of an isolation transformer and by applying a Duty-Cycle Shifted PWM Control

Method of adaptive solar tracking using variable step size

A method for controlling a photovoltaic (PV) panel in a PV system including a computing device that provides motor control signals and implements an iterative adaprtive control (IAC) algorithm for adjusting an angle of the PV panel. The IAC algorithm relates P at a current time k (P(k)), an elevation angle of the PV panel at k (0s(k)), P after a next step (P(k+1)) and an elevation angle of the PV panel at k+1 (0s(k+1)). The algorithm generates a perturbed power value P(k+1) to provide a power perturbation to P(k), and calculates 0s(k+1) using P(k+1). The motor control signals cause the motor to position the PV panel to achieve 0s(k+1). A change in P resulting from the positioning is compared to a predetermined change limit, and only if the change in P is greater than/equal to the change limit, again sensing P, and repeating the generating, calculating and positioning

Symbolic Switch/Linear Circuit Simulator Systems and Methods

Interactive and real time web-based electrical circuit symbolic solvers and simulators. The invention includes and interactive and innovative graphical user interface (GUI) for creating circuit schematics and generating netlists, circuit symbolic solving and instant simulated solutions, their systems and methods. Users such as students can use GUI interfaces to to remotely access a remote server controlled by educational institutions such as universities, or electronic book publishers, in order to draw, symbolically solve, and instantly simulate electrical circuit