The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The cascade multilevel inverter can reduce the voltage stress of the power switches and output filter inductance, also it is easy to modularize and some phase voltages are redundant, so it is very suitable for high voltage applications. In this paper a multi-level cascaded DC/AC converter with on single DC power source are presented and a practical modulation are give. The stepping modulation method...
This paper addresses a new multi-carrier modulation technique called wave shift multi-carrier modulation (WSHM), which used to control the cascade multilevel converter (CMC). The proposed switching technique generates lower voltage total harmonic distortion (THD) in comparison with conventional multi-carrier based pulse width modulation (PWM) schemes, phase-shift (PSHM) and level-shift (LSHM) modulations...
In this paper, a Pulse Width Modulation (PWM) technique for modular multilevel converter has been explored. The PWM technique is implemented using carrier based level shifted PWM strategy. It does not necessitate the calculation of duty cycles, and can be easily implemented in a DSP. With the proposed technique, harmonics in the phase voltage is shifted to twice the switching frequency. Thus, the...
EMI measurement and separation of the Common and the Differential Mode components of noise is necessary to design proper filter to mitigate EMI. It is also important to determine, which component is dominant in a particular frequency range so that the power supply filter may be modified to suit the regulatory limits. Fourier series Analysis is used in this paper to determine the area of dominance...
The paper deals with the analysis of accuracy of averaged models of DC-DC converters in the frequency domain. The averaged models of Boost, Buck and Buck-Boost converters are compared with results obtained using the harmonic balance method. It will be shown that the error of averaged models depends on the structure of state matrices and may reach a substantial magnitude even below the Nyquist frequency.
In this paper, a new method is proposed for switching a multilevel converter. In this converter two H-Bridge cells are connected in series with each phase of a three-phase diode-clamped converter. Operation of main converter and one of H-Bridge cells is based on the staircase switching method. Switching angles of the three phase converter and one of the H-Bridges are selected in a way to generate...
Harmonic currents generated from the power electric equipment such as IH cooking heaters involve harmful influences to the other equipments connected to the utility grid. As for the IH cooking appliances, adding the PFC converter to the input stage of IH cooking heater is one of the practical solutions to suppress harmonic current influences. In this paper, two operation modes; DCM and CCM for the...
This paper presents the development and the experimental analysis of a new single-phase hybrid rectifier with high power factor (FP) and low harmonic distortion of current (DHTI), suitable for application in Trolleybus electrical traction systems. This front-end rectifier structure is capable to operate in AC or DC distribution network platforms, providing significant improvements in trolleybuses...
A capacitor-less rectifier-inverter topology based on a fundamental frequency switched rectifier and a three-level flying capacitor is presented in this paper. The DC-link is free of any passive elements (capacitors, chokes or braking resistors). The removal of the large and bulky DC-link electrolytic capacitor, typically employed in rectifier-inverter topologies results in the elimination of a fault...
Several switching strategies have been developed to overcome the unbalanced working period and power sharing in cascaded multilevel inverters, but the power sharing problem is remained unsolved yet. In this paper, a novel switching method which equalizes the modules' power sharing is presented.
The main aim of this paper is to improve and further develop numerical iterative methods for calculating the optimum sequence of switching angles for the multilevel converter of direct to alternating voltage in the three-phase system. Advantages and disadvantages of numerical iterative methods and their application for finding a solution for multilevel converter with a higher number of DC sources...
AC-AC statistic Matrix converter is one of the most widely-used, and also very first, power electronics systems. These converters are conventionally designed and produced with a middle DC circuit. Because of the volume size and the short lifetime of electrolyte capacitors used in the middle DC circuits, their reliability level decreases. The direct AC-AC converter does not have such shortcomings....
This contribution provides comprehensive development procedures and mathematical models of an adjustable speed drive (ASD) for steady-state solutions. A complete representation of the ASD is employed, which includes the detailed models of the diode rectifier and of the inverter. The power electronic switches are efficiently represented through a smooth function that allows a larger integration step...
This paper presents a non-dissipative snubber circuit for minimizing switching losses in a single-phase single-stage power factor correction (PFC) converter. The snubber reduces the commutation losses for a bidirectional switch, which is used in the PFC. Due to input voltage for the PFC is a sinusoidal waveform, conventional snubber circuits on the main switch, developed for typical dc-dc converters,...
This paper proposes the development of dodecagonal (12-sided) space vector diagrams from cascaded H-Bridge inverters. As already reported in literatures, dodecagonal space vector diagrams have many advantages over conventional hexagonal ones. Some of them include the absence of 6n±1, (n=odd) harmonics from the phase voltage, and the extension of the linear modulation range. In this paper, a new power...
A number of PWM techniques have been developed in recent times for five-phase voltage source inverters (VSIs), which enable sinusoidal output voltage generation. Relatively little attention has been however paid to the current ripple caused by these PWM methods. This paper investigates stator current ripple (THD), caused by the switching harmonics, for two space vector PWM (SVPWM) techniques that...
This paper introduces an optimization based approach towards steady-state analysis of switched power electronic systems. The convergence performance of the optimization is improved by the estimation of the state variables in steady-state. Accurate state variable estimation can be achieved by previously simulating a set of multi-resolution approximations - averaged models of the original topological...
The switching loss minimized PWM method for flying capacitor three-level inverter is presented based on the study of PSPWM and SVPWM for flying capacitor multilevel inverter in the paper. In comparison with conventional carrier-shifted PWM method, each phase of the flying capacitor multilevel inverter can have the 120° no switching zone in one period by the proposed method; according to power factor...
Based on the sinusoidal pulse width modulation technology and regular sampling method, the switching time points calculation formulas of tangent method and secant method are established. This paper analyses the precision of switching turn-on and turn-off time point, and compare these switching time points. Calculation results show that SPWM pulses generated by tangent method and secant method are...
The influence on input current harmonics by single-edge modulation of conventional one-cycle control (OCC) in single-phase PFC converters is analyzed. The relation between low-frequency odd harmonics of the inductor current and modulation scheme is revealed. Based on the analysis, bi-edge modulation with triangular-wave as carrier is proposed. The inductor current is modulated both at leading- and...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.