The development of a simulation platform for the study and conception of current INJECTION technique to improve power factor, to reduce current HARMONICs generated by a DC drive in high power application is discussed. This work proposes the simultaneous current INJECTION in all the three phases. Two current shaping networks and current INJECTION devices are applied for HARMONIC reduction and power factor improvement. Based on the simulated results, optimal current shaping network, current INJECTION device, and firing angle are recommended. The work is carried out for converter at different firing angles and is simulated using MATLAB.

In this paper, a new approach for improving the linearity characteristics of GaN power amplifiers is presented. The method is based on the INJECTION of the second HARMONIC signal to the input of the power amplifier through a forward path. The effect of the second HARMONIC INJECTION on the linearity characteristics of the power amplifier is studied using two-tone theory and simulations. An active three-port linearizing circuit with the ability to generate a second HARMONIC signal with adjustable amplitude and phase has been proposed to implement this method. Further, the paper method has been evaluated for improving the linearity of two 10-watt power amplifiers with different nonlinear characteristics. As a concept, the proposed circuit is also fabricated and used for linearizing the GaN power amplifier. It has been shown that by injecting the second HARMONIC signal and properly adjusting its amplitude and phase, in addition to improving the linearity characteristics, including THIRD-order intermodulation (IMD3), adjacent channel power ratio (ACPR), and AM-PM characteristic, the 1-dB compression point is also increased.

This paper presents the design and evaluation of a high-efficiency HARMONIC tuned L-band power amplifier (PA) utilizing a Gallium Nitride (GaN) High Electron Mobility Transistor (HEMT). To meet the demands of modern wireless communication and radar systems operating in the L-band, advanced HARMONIC tuning techniques were employed, specifically focusing on controlling the impedance terminations at the second (2f₀) and THIRD (3f₀) HARMONIC frequencies. Through careful load-pull analysis and optimized output matching network design, precise HARMONIC terminations were achieved alongside optimal fundamental frequency impedance matching. The fabricated PA demonstrates state-of-the-art performance, delivering a saturated output power (Psat) of 46.4 dBm with a corresponding peak Power Added Efficiency (PAE) of 83%. Critically, the PA maintains high efficiency under back-off conditions, achieving 60% PAE at 3 dB output back-off (OBO). These results highlight the effectiveness of this combined second and THIRD HARMONIC optimization approach with GaN HEMT technology, which enables both high peak efficiency and excellent back-off efficiency for demanding L-band applications.

The Z-source converter was first introduced as a buck-boost dc-ac single-stage inverter in 2003. Different structures of impedance source inverters have been introduced for improving the performance of power inverters. Due to their specific structure, these inverters use shoot-through state in order to increase the output voltage. Therefore, in addition to improving the reliability of systems, they create a single-stage dc-ac inverter capable of reducing and increasing voltage at the same time. Recently, a three-winding network called the A-source network has been introduced. A new Pulse Width Modulation method has been proposed to improve the voltage gain and reduce switching losses. In this new method, duty cycle of the switch is controlled using the THIRD HARMONIC INJECTION and the new reference voltages in the three-phase A-source inverter. The proposed modulation method reduces the switching losses and increases voltage gain without adding any additional hardware to the inverter structure. In this method, the buck-boost single-stage structure of the inverter is maintained. In this paper, the proposed method is partially analyzed and compared to the conventional Pulse Width Modulation methods. In this method, the THIRD HARMONIC INJECTION is used to increase the modulation index to 1. 15 and thereby reduce the switching losses. The simulation of the proposed and conventional methods and analyzes, demonstrated the ability of the proposed system.

Resonant THIRD HARMONIC generation of super-Gaussian laser beam in rippled density plasma is studied. Both the relativistic and ponderomotive nonlinearities are included in the analysis, and the study is done for self-guided laser beam. The quasistatic component of ponderomotive force creates electron density depression in the beam region while the second HARMONIC component leads to second HARMONIC density oscillations, leading to THIRD HARMONIC generation. The relativistic mass variation supplements these processes with same order of contributions. The ripple provides the phase matching and requisite ripple wave number decreases with the frequency of the laser.

In this article, based on the nonlinear property of graphene and placing a layer of graphene on a suitable substrate, a plasmonic waveguide based on suspended graphene has been proposed for the first time to enhance THIRD HARMONIC generation(THG). The role of different parameters of single-layer graphene in resonance properties and nonlinear conductivity of graphene has been determined. It is shown that by changing the electrochemical potential of graphene, it is possible to tune the THG, which is based on the nonlinear properties of monolayer graphene. The finite difference computing method in the time domain (FDTD) has been used for numerical simulation and analysis of the proposed structure in the mid-infrared wavelength range. In our simulations, the conversion efficiency was calculated at about -48.08 dB, which shows a significant increase compared to other sources. Using high quality graphene samples and floating them and finally using Si3N4 dielectric has improved the performance of the proposed structure compared to other references. The result of this work can be used to develop a wide range of important applications such as new frequency generation, signal processing, chemical sensing and switches in the MIR frequency range.

In this paper the method of sensorless startup of direct current brushless motor using THIRD HARMONIC back Electromotive Force (EMF) and motor startup using microcontroller for pulse width modulation, power switch control and motor output analysis is presented which renders RPM control and high speed achievement for motor. The microcontroller is used for processor and metal-oxide semiconductor field-effect transistor (MOSFETs) are used for power circuit. Besides, the motor does not have any sensors to detect rotor position. Furthermore, the microcontroller modulates pulse width, controls power circuit and analyses motor output. The innovation in this research is that the THIRD HARMONIC function is used for motor control and is compared with the Back-EMF force to recognize zero crossing. Moreover, N-type MOSFETs are used in power circuit high side and low side which are useful in the current rate of MOSFETs due to their similarities. Also, the IR2101 MOSFET drive is utilized for startup which improves the firing time of MOSFETs. Besides, using tantalum capacitors and putting resistor by the gate route of MOSFETs is efficient. Finally, experimental results are given to verify the validation of the proposed method.