RLC circuit

About: RLC circuit is a research topic. Over the lifetime, 14490 publications have been published within this topic receiving 142697 citations.

Adaptive piezoelectric shunt damping

Abstract: Piezoelectric shunt damping systems reduce structural vibration by shunting an attached piezoelectric transducer with an electrical impedance. Current impedance designs result in a coupled electrical resonance at the target modal frequencies. In practical situations, variation in structural load or environmental conditions can result in significant changes in the structural resonance frequencies. This variation can severely reduce shunt damping performance as the electrical impedance remains tuned to the nominal resonance frequencies. This paper introduces a method for online adaptation of the shunting impedance. A reconstructed estimate of the RMS strain is minimized by varying the component values of a synthetic shunt damping circuit. The techniques presented are applied in real time to tune the component values of a randomly excited beam.

High efficiency constant current led driver

Abstract: The present invention discloses a high efficiency constant current LED driver, which comprises a rectification bridge, a PFC main circuit, an isolated DC/DC converter, a PFC controller and a PFC bus control circuit. Since the input voltage is an intermediate PFC bus voltage, which varies with the output voltage of the DC/DC converter. When the isolated DC/DC converter is an LLC resonant circuit, the operating frequency of the LLC circuit is close to the resonant frequency within a wide output voltage range. Thus, the gain range and the operating frequency is narrow, and can enable the constant current module to work with a high efficiency at a wide output voltage range. When the isolated DC/DC converter is a symmetric half bridge, or an asymmetric half bridge or a full bridge circuit, the duty cycle of DC/DC circuit is close to 50% within a wide output voltage range. Thus, the changing range of the duty cycle of the DC/DC converter will be narrow and can improve the efficiency dramatically.

Filter networks for long cable drives and their influence on motor voltage distribution and common-mode currents

Abstract: Filter networks for long cable drives have been studied in the last decade to solve the overvoltage problem at the motor terminals. However, little research has been dedicated to analyze their influence on the voltage distribution in the motor stator winding and on the circulation of the common-mode currents. In this paper, the project of dv/dt filters through simulation and analysis from previous work is extended, including the motor voltage distribution and common-mode current analysis. Simulation and experimental results are presented, demonstrating the usefulness of the filter networks on the motor overvoltage mitigation. Three filter topologies will be discussed and compared here: RLC filter at the motor terminals, RLC filter at the inverter output and reactor filter, which is extensively used in the industry. Simulation and experimental results demonstrate that the RLC filter at the inverter output is the most interesting solution among the main types of passive filter networks.

Analysis and design of class-E/sup 2/ DC/DC converter

Abstract: A family of class-E/sup 2/ DC/DC power converters is introduced. Their analysis and design are presented and experimentally verified. The converters are composed of class-E inverters and class-E rectifiers. Zero-voltage switching (with low dv/dt) of the transistor and zero-current switching (with low di/dt) of the rectifier diode reduce switching losses in both stages of the converters, making them especially suitable for high-frequency operation. Because of the high loaded quality factor of the resonant circuit, the range of frequency required for output-voltage regulation is as narrow as 5.46% for load resistances from a full load of 100 Omega to an open circuit. The full-load overall efficiency is 80.36% at 1 MHz. The converters can also operate at a fixed frequency if synchronous rectifiers are applied. The reduction of class-E/sup 2/ converters to lower order converters is presented. Many multiresonant converter topologies are created in this way. The class-E/sup 2/ converters can be utilized to build highly efficient high-power-density switching power supplies. >

DC analysis technique for inductive power transfer pick-ups

Abstract: Inductively coupled power transfer (ICPT) systems are now being used in applications where their efficiency and stability are critically important. In this paper, an ICPT pick-up is analyzed under conditions where the pick-up tuning is assumed to be essentially perfect, and all diodes are assumed to have continuous current flow in them. The analysis proceeds by replacing the existing parallel resonant tank and rectifier circuit with a DC source and transformer equivalent, thereby reducing the complexity of the circuit, and eliminating the diodes. The DC equivalent is shown to have the same energy storage and power capability as the original circuit and is accurate under all loadings for both transient and steady-state conditions. With this simplification, analytic transfer functions for the pick-up with respect to its excitation current and its control switch duty cycle are developed. The ICPT system model is shown to have multiple poles, with complex zeroes on the right half plane. The model allows a sophisticated controller to be designed to give the ICPT system the required stability at high efficiency.