Sharif Digital Repository

Today's technology is going to be switched to power electronics equipment due to their wide applications in industries. Their development is too fast since the electronic and microprocessor technology promoted together, which play a significant role in this issue. In this paper, a novel boost converter with an h-bridge auxiliary LCC resonant circuit which provides soft switching technique to the converter is introduced. Then different modes of its operation are investigated and key parameters of the converter are extracted. Finally, simulation analyses are carried out to validate each mode's equation. In this study, the proposed structure of auxiliary circuit permits converter to work in... 

In this paper, design and analysis using analytical expressions for the inverse class-E power amplifier (PA) operating at the outside nominal operation, i.e., class-En PA, is presented. This operation is defined as non-zero current switch (n-ZCS) and non-zero derivative current switch (n-ZDCS) conditions. The generalized design equations as a function of design specifications, load-resistance and a given dc-supply voltage are derived. Two degrees of the design freedom achieved thanks to n-ZCS and n-ZDCS that are utilized for the simultaneous satisfaction of design specifications, such as peakswitch- voltage and peak-switch-current along with a given loadresistance. The output power... 

In this paper, a single-inductor dual-output (SIDO) DC/DC converter is proposed. The significant feature of the proposed converter is feeding a constant power load in low voltage side (LVS) port, where even feeding a variable load at LVS doesn't have any cross regulation to high voltage side port with the desired approximation. Magnificently, both merits are obtained in open-loop manner which is an outstanding characteristic in comparison with existed converters. In this paper, soft commutation and soft switching of switches and diodes are investigated along with the aforementioned main novelty. Moreover, detailed theoretical analyses of the proposed SIDO DC/DC converter in continuous... 

In this study, a new multi-input high step-up inverter, based on isolated soft-switching DC-DC converter blocks is proposed. Each of these blocks can provide zero-voltage and zero-current switching for its semiconductors, which improve power efficiency. The interesting feature of this DC-DC converter is using bidirectional switches to generate both positive and negative output voltage levels in each DC-DC block with an appropriate control scheme. Each DC-DC converter operates by simple pulse width modulation control through fixed frequency and has two degrees of freedom, which provide the capability of output voltage regulation or maximum power point tracking. The proposed inverter consists... 

This paper presents a stabilizing controller design method for quasi resonant (QR) converters described by a class of piecewise linear (PWL) models. The generalized state-space averaging technique (GSSA) is applied for the modeling and analysis of the half-wave zero current switching quasi-resonant (HW-ZCS-QR) buck converter. The nonlinear GSSA model of the converter is reconstructed using a piecewise linearizing technique. Subsequently, the piecewise linear models are combined together, to form a unified model, using a fuzzy modeling approach. The stability of the applied method has been investigated using Lyapunov method. Finally, a linear Hinfty; controller synthesis method is applied to... 

LLC resonant converter with significant resonant inductance is proposed for designing an adjustable wide-range regulated voltage source. Large resonant inductance increases output voltage adjustment range and conversion efficiency, particularly at light loads. Soft switching is achieved for all power devices under all operating conditions by choosing the dead time and maximum switching frequency properly and operating in the converter's inductive region. Using a power-factor-correction (PFC) converter reduces the resonant converter's output voltage dependence to the variations of the main ac input voltage. Thus, the compensation of the load variations and the wide-range adjustment of the... 

Due to the fast response of skip cycle modulation technique, it has been used to control of some DC/DC converters. In this paper, it is used to control of a series resonant converter. A pulse generator circuit is presented for zero current switching. Simulation and experimental results are presented to show the features of this control method. Results show that the converter has a fast response and high efficiency. Design notes about magnetic parts of converter are also presented to achieve the highest efficiency  

In this study, a new LLC resonant converter for high-voltage high-power applications is introduced. The introduced power converter is a two-phase interleaved full-bridge based that uses a transformer with secondary and tertiary windings to obtain higher output voltage. Zero voltage switching (ZVS) at MOSFETs turn on and zero current switching (ZCS) for all the output diodes at turn off are achieved for a wide range of input voltage (100 V-200 V) and output power (200 W-1500 W) variations. Simulation results show a 95% peak efficiency. © 2021 IEEE  

A new high step-up boost converter with an active clamp circuit to eliminate voltage spike caused by leakage inductor is introduced in this paper. The introduced power converter has a high voltage gain for variable input voltage from 48V to 80V. Since both main and auxiliary switches turn on with zero voltage switching (ZVS) and all the diodes turn off under zero current switching (ZCS) condition, switching losses and EMI noises are strongly degraded. Therefore, the converter's efficiency is improved significantly. Simulation results show a 96.4% peak efficiency and 95.4% average efficiency. The proposed topology is suitable for low-input-voltage and low-output power applications such as... 

In this paper, design and analysis using analytical expressions for the inverse class-E power amplifier (PA) operating at the outside nominal operation, i.e., class- $ ext{E}-{mathrm{n}}$ PA, is presented. This operation is defined as nonzero current switch (n-ZCS) and nonzero-derivative-current switch (n-ZDCS) conditions. The generalized design equations as a function of design specifications, load resistance, and a given dc-supply voltage are derived. Two degrees of the design freedom achieved thanks to n-ZCS and n-ZDCS that are utilized for the simultaneous satisfaction of design specifications, such as peak-switch-voltage and peak-switch-current along with a given load resistance. The... 

LLC resonant converter is one of the most suitable circuit topologies that have been introduced for designing constant output voltage switched-mode power supplies. In this paper, a design procedure is introduced for using this converter as a wide output range voltage source. Unlike constant output voltage applications which need small converter inductance ratio and narrow switching frequency variations, for wide output range applications, large values of these parameters are needed simultaneously and should be optimized. Instead of minimizing the components stresses, leading to a great value of the inductance ratio, proper choice of the converter parameters resulting in a smaller inductance... 

In this paper a novel soft switching three-phase pulse width modulation (PWM) rectifier is proposed. Various switching state sequences of a three-phase three-switch buck-type unity power factor rectifier are reviewed and the operation modes of the converter are explained and analyzed. The converter operates under zero current switching (ZCS) condition. By using an auxiliary circuit with a simple method of energy recovery, the current is diverted away from the main power switches before they are to be turned off; so, switching losses in the converter are reduced. The auxiliary circuit consists of two auxiliary switches and a resonant inductance-capacitance circuit connected to the auxiliary... 

This paper gives the design and analysis approaches for the class-E power amplifier with a shunt inductor under the nominal conditions, i.e., zero-current switching (ZCS) and zero-current derivative switching (ZCDS), with taking into account the MOSFET nonlinear output parasitic capacitance at any duty ratio. Although, the class-E ZCS/ZCDS conditions obtained high-efficiency, but the switch-current waveform affected by the slope of the voltage across the MOSFET nonlinear drain-to-source parasitic capacitance during the switch-off state, which restricted the operating frequency. On the other hand, the duty ratio is an adjustment parameter to obtain high-frequency operation. Therefore, the... 

In this paper, a novel zero-voltage-switching topology for power factor correction bridgeless boost rectifier is proposed. By employing an improved switch cell, ZVS for all the main switches is achieved without additional current or voltage stress. The zero-current-switching is also provided for the auxiliary switch. In all modes of operation of this converter, the input current flows through only two semiconductors. Therefore, conduction loss of this converter is as low as the conventional parent converter. With these features, the efficiency of the proposed converter is very high. A 500 W prototype is designed and simulated to verify the system performance  

This paper proposes a design technique for the implementation of a class-EM power amplifier (PA). Class- EM mode of operation has been proposed as an improved version of class-E in terms of efficiency and power gain, provided that the current fall time of switch is an appreciable portion of a period; the frequency of operation is high enough that the switching time of transistor can no longer be considered instantaneous. A novel approach for harmonic injection required for class-EM operation is proposed, followed by the system of equations and the design methodology governing the proposed circuit. As a proof of concept and verification of the proposed design method, a class-EM PA is designed... 

This paper proposes a new variable frequency zero voltage switching (ZVS) control method for boost converter operating in boundary conduction mode (BCM). The intended method keeps the converter in BCM despide of the load and input voltage variations. This is done by changing switching frequency in a certain specified range. The proposed method can guarantee circuit performance in BCM via zero-crossing detection of the inductor current and changing the switching frequency. In addition, with a slight modification in control structure, it is possible to achieve a fully ZVS in all cases. This converter control is carried out in analog form without using microprocessors which, compared with the... 

In this article, a new soft switching isolated push-pull dc-dc converter using a three-winding transformer is proposed. The proposed hybrid resonant and pulse width modulated converter employs a conventional push-pull structure in the primary side, a voltage doubler in the secondary side, and a bidirectional switch besides the transformer, altogether help offering a high efficiency over a wide range of input and output voltage signals with an unsophisticated fixed-frequency control mechanism. The primary-side switches are commutated under zero voltage switching with low switching current and the secondary-side diodes are commutated under zero current switching. In this article, we first... 

LLC resonant converter has been used widely as dc-dc converter for achieving constant dc voltage. In this paper, an LLC resonant converter, by adding an inductance to its conventional topology and considering the rectifying stage stray inductances, is proposed for an adjustable wide range regulated current source (20-200 A dc) for using as ion implanter's filament power supply. The additional inductor increases output current adjustment range and efficiency, especially at light loads. Transformer's leakage inductances and rectifying stage stray inductances have been considered. Because of these inductances, the rectifier stage always works in continuous conduction mode, and its conduction... 

In this paper, different model predictive control synthesis frameworks are examined for DCDC quasi-resonant converters in order to achieve stability and desired performance. The performances of model predictive control strategies which make use of different forms of linearized models are compared. These linear models are ranging from a simple fixed model, linearized about a reference steady state to a weighted sum of different local models called multi model predictive control. A more complicated choice is represented by the extended dynamic matrix control in which the control input is determined based on the local linear model approximation of the system that is updated during each sampling...