RLC circuit

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

A zero-voltage switched PWM boost converter with an energy feedforward auxiliary circuit

Abstract: A zero-voltage-switched (ZVS) pulsewidth-modulated (PWM) boost converter with an energy feedforward auxiliary circuit is proposed in this paper. The auxiliary circuit, which is a resonant circuit consisting of a switch and passive components, ensures that the converter's main switch and boost diode operate with soft switching. This converter can function with PWM control because the auxiliary resonant circuit operates for a small fraction of the switching cycle. Since the auxiliary circuit is a resonant circuit, the auxiliary switch itself has both a soft turn on and turn off, resulting in reduced switching losses and electromagnetic interference (EMI). This is unlike other proposed ZVS boost converters with auxiliary circuits where the auxiliary switch has a hard turn off. Peak switch stresses are only slightly higher than those found in a conventional PWM boost converter because part of the energy that would otherwise circulate in the auxiliary circuit and drastically increase peak switch stresses is fed to the load. In this paper, the operation of the converter is explained and analyzed, design guidelines are given, and experimental results obtained from a prototype are presented. The proposed converter is found to be about 2%-3% more efficient than the conventional PWM boost converter.

Arrangement of a data coupler for power line communications

Abstract: An arrangement for coupling data between a power line (300) and a communication device (325) includes an inductive coupler (305) that employs a power line conductor as a primary winding, a capacitor (310) connected across a secondary winding of the inductive coupler (305) for creating a resonant circuit with the secondary winding at a frequency within a desired frequency band, and an impedance matching transformer (315) for connecting a communications device (325) to the secondary winding. The resonant circuit has a loaded Q consistent with the desired bandwidth. An alternative arrangement includes a capacitor (410) in series with conductive cylinder section (505) and (510) between the power line and communication device (435), where the capacitor is for blocking power line voltage while passing a signal between the power line and the communication device, and the conductive cylinder sections (505) and (510) appears as a low inductance to the signal.

A bandwidth enhancement technique for mobile handset antennas using wavetraps

Abstract: A novel technique for enhancing the impedance bandwidth of wireless terminal antennas is presented. By introducing resonant short circuit transmission lines to the long sides of the chassis edges, an effective electrical shortening of the terminal ground plane is achieved. This effect has been used to realize terminal ground planes with resonant lengths at high frequencies, such as GSM 1800/1900 MHz or UMTS 2 GHz, thereby extending the impedance bandwidth. The proposed technique has been validated by simulations and measurements. Three typical applications are presented where the introduction of wavetraps improves the bandwidth and/or in-band performance

Self tuning pick-ups for inductive power transfer

Abstract: Inductive power transfer systems are now commonly used in ultra clean or dirty industrial applications to deliver power to both moving and stationary loads without contact. Each load requires a power pick-up and regulator that is coupled to a track, which carries a resonant current at VLF frequencies (typically 10-50 kHz). Modern pick-ups are tuned for resonance at the track frequency and their power delivery increasingly depends on accurate tuning of the resonant circuit. In this paper a new self tuning power regulator for inductive power transfer systems is proposed and a control strategy described. The system uses a binary weighted series of capacitors that can be switched via simple relays across a parallel resonant pick-up circuit. There are no additional switching losses during tuning, detection and operation so that the technique is applicable to high power pick-ups. The tuning circuit is evaluated under simulation and then made to operate on a practical 500 W pick-up regulator used in materials handling applications. In both simulation and experiment it is shown to successfully detect the tuning state of the system and correct for it during operation.

Results of Investigation of Multicell Converters With Balancing Circuit—Part II

Abstract: This paper presents the results of an investigation of the multilevel multicell converters with a passive RLC balancing circuit applied for the maintenance of the voltage sharing on the capacitive sources of the converters. The topologies of DC/DC, AC/AC, DC/AC, and AC/DC multicell converters were analyzed. For the purpose of multilevel modulation, a multicell converter employs several capacitors that are connected to every cell-the flying capacitors, charged to a given level of voltage. An inadequate relation between the voltages across the flying capacitors (the unbalance state) results in the increase of the voltages above their rated values across the switches. An RLC series circuit (a balancing circuit) with the properly selected resonance frequency is connected in parallel to the load in order to eliminate the unbalance. The balancing process with the use of passive RLC depends on the configuration and parameters of the balancing circuit, the parameters of the converter, as well as on the operating conditions. This paper presents the mathematical description of both the converter and the balancing process, the balancing circuit approach in the different topologies of the multicell converters, a selection of the balancing circuit parameters, and the analysis of the improper control conditions.