Negative impedance converter

About: Negative impedance converter is a research topic. Over the lifetime, 5801 publications have been published within this topic receiving 87636 citations.

A novel soft-switching high-frequency transformer isolated three-phase AC-to-DC converter with low harmonic distortion

Abstract: A high-frequency transformer isolated, fixed-frequency, 3-/spl phi/ single-stage ac-to-dc converter using a boost-integrated bridge converter that employs a new gating scheme is proposed. This converter enjoys natural power factor correction with low line current harmonic distortion and symmetric high frequency voltage and current waveforms while ensuring zero-voltage switching for all the switches for a wide variation in load and line voltage. Various operating modes of the converter are presented and analyzed. Based on the analysis, design curves are obtained and an optimum design is given. A design example is presented. Results obtained from SPICE simulation and a 500 W output experimental prototype are given to verify the performance of the proposed converter for varying load as well as line voltage.

Method and apparatus to match output impedance of combined outphasing power amplifiers

Abstract: Briefly, an apparatus having a first capacitor-inductor-capacitor impedance converter operably coupled to a second capacitor-inductor-capacitor impedance converter. The first and second capacitor-inductor-capacitor impedance converter may combine a first and second signals of first and second outphasing power amplifiers and may provide a matched output impedance to a desired load.

Analysis and control of isolated current-fed full bridge converter in fuel cell system

Abstract: Fuel cells are considered as one of the most prominent sources of green energy in future. However, the potential efficiency of fuel cell will be untapped unless an efficient method can be used to convert the fuel cell low voltage to high voltage grid or user load. Many topologies have been proposed for such applications. However, most of them consider the fuel cell as an voltage source instead of a current source. In this paper, an isolated current-fed full bridge boost converter is proposed as the front-end of the fuel cell system, which is more compatible with the fuel cell particularities. Small signal analysis is applied to the converter and current control method is used. Simulation and experiment results are shown to verify the analysis.

New zero-voltage switching DC-DC converter for renewable energy conversion systems

Abstract: This study presents a novel DC–DC converter for renewable energy conversion systems with photovoltaic (PV) solar cell or fuel cell stack input. The proposed converter is based on a boost converter and a voltage-doubler configuration with a coupled inductor to achieve high step-up voltage conversion ratio. An active snubber is adopted to clamp the voltage stress of the active switch and to release the energy stored in leakage and magnetising inductances. Compared to a conventional boost converter, the adopted converter has a wide turn-off period such that a high output voltage can be achieved. Since an asymmetrical pulse-width modulation is adopted to control both active switches, the leakage inductance and output capacitance of the active switch are resonant in the transition interval. Therefore both active switches are turned on at zero-voltage switching to overcome the disadvantages of a conventional boost converter with low circuit efficiency and narrow turn-off period. Finally, experiments conducted on a laboratory prototype rated at 400 W are presented to verify the effectiveness of the adopted converter.

Single-ended-to-differential converter with common-mode voltage control

Abstract: Provided is a circuit to perform single-ended to differential conversion while providing common-mode voltage control. The circuit includes a converter to convert a single-ended signal to a differential signal and a stabilizing circuit adapted to receive the differential signal. The stabilizing circuit includes a sensor configured to sense a common-mode voltage level of the differential signal and a comparator having an output port coupled to the converter. The comparator is configured to compare the differential signal common-mode voltage level with a reference signal common-mode voltage level and produce an adjusting signal based upon the comparison. The adjusting signal is applied to the converter via the output port and is operative to adjust a subsequent common-mode voltage level of the differential signal.