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This paper presents a commutation technique to overcome the effects of transformer leakage inductance in a single stage high frequency ac-link transformer isolated inverter. The presence of leakage inductance causes large voltage spikes across the transformer due to the switched nature of link current that is encountered in direct high frequency ac link to low frequency ac conversion. This paper proposes...
In the present work, a modified auto-adaptation unit is presented for switching between different wireless standards. The adaptation unit provides an architectural level flexibility to reconfigure the resolution of the analog to digital converter, irrespective of the converter circuit. The adaptation unit generates control bits that give the measure of the input wireless standard and provide the reconfigurable...
A breadboard model of the store of kinetic energy with an asynchronized electric machine and a cascade frequency converter in a rotor circuit is created. The converter is executed on the basis of a single-phase blocks connected to the network through transformers and connected from the rotor consistently in each phase. Transformation blocks contain single-phase active rectifiers and voltage inverters...
This paper presents a low power CMOS current steering multivibrator based VFC, which can be used for analog front end interfacing of sensors in telemetry applications. The proposed circuit is designed in 180 nm CMOS technology with 1.8V power supply. It operates at full scale input voltage range and the output frequency ranges from 0.38MHz to 4.69MHz. The peak total power consumption observed is 182...
The authors present the results of experimental work on a small-power direct driven permanent magnet synchronous generator reactive power compensation comparison with two methods. Particular generator is targeted for small size wind power systems, and is tested on a wind turbine emulator that consists of an AC induction motor, a frequency converter and a torque feedback. Generator output power was...
Currently, with the tendency of the smart grids in the power line distribution, the solid-state transformer become a suitable solution for this kind of the application. Several researchers are developing solid-state transformers in electric traction applications in order to reduce size and weight of traditional 50/60 Hz transformers. However there are studies in the area of smart grids. This paper...
This paper presents a novel switching scheme named as Switched Rectifier Inverter (SRI) modulation scheme for three phase to single phase (3×1) Matrix converter based isolated AC-DC converter. The proposed SRI modulation scheme incorporates symmetrical Space Vector Modulation (SVM) with inverter logic for switching the twelve switches of Matrix based AC-DC converter. The operation of proposed SRI...
Control, design and operational characteristics of multilevel modular matrix converter (MMxC), which conducts ac/ac direct frequency conversion, are presented in this paper. MMxC consists of a large number of H-bridge cells connected in series and thus is suitable for high voltage and high power applications. After brief explanation about power flow and capacitor voltage balancing control schemes,...
In this paper, a detailed design procedure is presented for a bidirectional resonant converter for battery charging application. This converter is similar to the LLC resonant converter with an extra inductor and capacitor in the secondary side. Soft-switching can be ensured in all switches without additional circuitry, and because of that, very high frequency operation is possible, hence; the size...
In recent years, Modular Multilevel Converter (MMC) is an emerging and highly attractive multilevel converter topology for High Voltage Direct Current (HVDC) transmission and Flexible AC Transmission System (FACTS). The technology on how to balance the floating DC capacitors plays a key role in the new converters. A Fundamental Frequency Sorting Algorithm (FFSA) based on Carrier Phase Shift PWM (CPS-PWM)...
The instantaneous output power of the two-stage single-phase inverter pulsates at twice the output voltage frequency, resulting in the second harmonic current (SHC) in the front-end dc-dc converter. Although various control schemes can effectively reduce the SHC, they might make the front-end dc-dc converter suffer from poor dynamic performance. In this paper, a basic approach is proposed from the...
Cascaded H-Bridge converters are an attractive topology for automotive applications due to the potential improvements in motor efficiency and the system modularity they offer. Isolated voltage sources are required in this structure and one approach to providing these is use of the Dual Active Bridge converter. Regardless of the number of phases in the load, each element in the cascade supplies a single...
This paper presents effects of DC link capacitor sizes in a three phase diode rectifier on input current harmonics at a system level. A small DC link capacitor generates a resonant frequency with a line inductor which can affect and increase the input current harmonics. According to IEC 61000-3-2 and IEC 61000-3-12 standards, low order current harmonics of a power electronic system should be controlled...
This paper proposes to utilize the fixed-frequency Pulse-Width Modulation (PWM) control strategy to replace the traditional phase-shift modulation for realizing an interleaved three-level LLC resonant converter. Result obtained from this research is suitable for application in areas where high voltage, high power, and high stability DC-DC conversion is required. The proposed converter consists of...
Recently, Voltage Source Converter (VSC) based High Voltage Direct Current (HVDC) transmission systems have gained more attention. In this paper, a control method for a modular VSC based HVDC transmission system with high frequency isolation referred to as high frequency isolated modular converter is proposed. In the high frequency isolated modular converter configuration, several floating DC capacitors...
In a rectification system with unity power factor, the input power consists of a DC and a double-line frequency power component. Traditionally, an electrolytic capacitor (E-Cap) is used to buffer the double-line frequency power such that the DC output presents a small voltage ripple. The use of E-Cap significantly limits the lifetime of the rectifier system. In this paper, a differential AC/DC rectifier...
Stability analysis of modern three-phase ac power systems is performed using small-signal impedances identified in synchronous reference dq frame. A single-phase series voltage injection is used to perturb ac and dc systems in order to perform small-signal impedance identification. This paper proposes to use interleaved cascaded H-bridge converter to generate a voltage perturbation in series with...
Excellent dynamic behavior and controllability even under fault conditions are main requirements of future electric drive systems. The Modular High Frequency Converter (MHF) fulfills these requirements and enables additional advantages especially low weight, low volume and redundant operation after faults. This paper presents control strategies and stability considerations for the new topology of...
By now the modular multilevel converter (MMC) is mainly applied to high frequency applications (50 or 60Hz) especially in the field of HVDC systems. This paper presents a control scheme for modular multilevel converter, which allows the converter to operate at continuous coverage in the 0Hz to 50Hz frequency band.
Wave energy converters generally suffer from a low operating power factor due to the nature of the long wavelength water wave and the inductance of the electrical generator employed in the conversion process. A Forced Commutated Series Capacitor (FCSC) converter can be connected between the generator and the load circuit to prevent power factor degradation. This paper describes the effectiveness of...
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