Analysis and Simulation of a High Performance Quasi Resonant PWM Inverter for Solar Power Generation

A quasi resonant pulse width modulation（PWM） inverter is used in a solar power system to convert the solar panel and battery charger＇s direct current（DC） output to alternating current（AC）.Although much has been published about DC to AC PWM inverters,none of the previous work has shown modeling and simulation results for DC to AC inverters.In this study,we suggest a new topology for a quasi resonant PWM inverter.Experimental results are also presented.

Multi-Phase QR ZCS Switched-Capacitor Bidirectional Power Converter for PV System Application

The multi-phase implementation in the QR （quasi resonant） ZCS （zero current switching） SC （switched capacitor） bidirectional DC-DC converter structure has been proposed to reduce current ripple, switching loss and significantly increase the converter efficiency and power density. This approach provides a more precise output voltage to obtain voltage conversion ratios from the double-mode versus half-mode to n-mode versus 1/n mode. This is accomplished by adding a different number of switched-capacitors and power MOSFET switches with a small series connected resonant inductor for forward and reverse schemes. The size and cost can be reduced when the proposed converter has been designed with the coupled inductors. The simulation and experimental results have been used to demonstrate the performance of the two-phase with and without coupled inductor interleaved QR ZCS SC converters for bidirectional power flow control application, and an extending structure for N-phase is mentioned.

Smith-Purcell free electron laser based on the semi-elliptical resonator

A novel Smith-Purcell （S-P） free electron laser composed of an electron gun, a semi-elliptical resonator, a metallic reflecting grating and a collector, is presented for the first time. This paper studies the characteristics of this device by theoretical analysis and particle-in-cell simulation method. Results indicate that tunable coherent S-P radiation with a high output peak power at millimeter wavelengths can be generated by adjusting the length of the grating period, or adjusting the voltage of the electron beam. The present scheme has the following advantages： the semi-elliptical resonator can reflect all radiation with the emission angle {？ and random azimuthal angles, back onto the electron beam with same-phase and causes the electrons to be modulated, so the output power and efficiency are improved.

Stochastic averaging of quasi integrable and resonant Hamiltonian systems excited by fractional Gaussian noise with Hurst index 1/2

A stochastic averaging method of quasi integrable and resonant Hamiltonian systems under excitation of fractional Gaussian noise （fGn） with the Hurst index 1/2 〈 H 〈 1 is proposed. First, the definition and the basic property of fGn and related fractional Brownian motion （iBm） are briefly introduced. Then, the averaged fractional stochastic differential equations （SDEs） for the first integrals and combinations of angle variables of the associated Hamiltonian systems are derived. The stationary probability density and statistics of the original systems are then obtained approximately by simulating the averaged SDEs numerically. An example is worked out to illustrate the proposed stochastic averaging method. It is shown that the results obtained by using the proposed stochastic averaging method and those from digital simulation of original system agree well.