Zero-current (ZC) switching pulse-widthmodulated (PWM) flyback DC-DC converter is an extended version of the single switch flyback converter with an additional active circuit. The purpose of the active circuit is to turn-off the main switch with zero-current switching (ZCS) condition to reduce the turn-off switching loss. This paper presents an overview of the ZCS flyback PWM DCDC converters. T...

The self-sustained discharge of excimers is analyzed. Several excitation schemes that have been successfully applied are compared. For high repetition rate operation not only the discharge stability and its efficiency are important selection criteria but more important is the potential of fast discharge switching with minimum pulse energy. Pulse compression plays a key role in the laser perform...

InGaAs quantum wells and a Bragg mirror structure are grown on a GaAs substrate to simultaneously serve as a low-loss saturable absorber and an output coupler for highly efficient Q switching of a diode-pumped Nd:YAG laser operating at 946 nm. With an incident pump power of 9.2 W, the laser produces pulses of 38 ns duration with average pulse energy of as much as 20 microJ at a pulse repetition...

To reduce the high-order harmonics produced by the high-power pulse width modulated (PWM) converters, selective harmonic elimination (SHE) scheme is commonly used due to its superior harmonic performance at low switching frequency. This Project proposes an active compensation method through the PWM control of SHE phase angle. An application example on a high-power PWM current-source rectifier (...

We report, for the first time to our knowledge, the experimental observation of quasi-cw nonlinear switching and multiple gap-soliton formation within the bandgap of a fiber Bragg grating. As many as five gap solitons with 100-500-ps durations were generated from a 2-ns pulse at a launched peak intensity of approximately 27 GW/cm(2). A corresponding increase in the grating transmission from 3% ...

We used a terahertz (THz) quantum cascade laser (QCL) as an integrated injection seeded source and amplifier for THz time-domain spectroscopy. A THz input pulse is generated inside a QCL by illuminating the laser facet with a near-IR pulse from a femtosecond laser and amplified using gain switching. The THz output from the QCL is found to saturate upon increasing the amplitude of the THz input ...

A passively switched Ho(3+), Pr(3+) codoped fluoride fiber laser using a semiconductor saturable absorber mirror (SESAM) is demonstrated. Q-switching and partial mode-locking were observed with the output power produced at a slope efficiency of 24% with respect to the absorbed pump power. The partially mode-locked 2.87 μm pulses operated at a repetition rate of 27.1 MHz with an average power of...

This paper studies dynamics of a delta modulator for PWM control. In order to analyze the circuit dynamics we derive a onedimensional return map of switching time. The map is equivalent to a circle map in wide parameter region and its nonperiodic behavior corresponds to undesired asynchronous operation of the circuit. We then present a simple stabilization method of the system operations by mea...

In this paper comparative study of proposed hybrid multilevel inverter (HMI) operating in modified pulse width modulation (PWM) mode with cascaded H-bridge multilevel inverter (CHMI) is done. Two types of HMIs are proposed with same configuration. To control the two HMIs, modified PWM techniques are derived from sinusoidal pulse width modulation (SPWM) to reduce the switching losses in the inve...