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Diode rectifiers and thyristor converters are very promising as a large current power supply for high field magnets such as fusion magnets, superconducting magnetic energy storage. The objective of this work is to discuss the power factor correction of the line commutated converters using variable series capacitors. The diode rectifier can control the DC voltage with a resulting leading power factor...
LED lighting driver design in TRIAC dimming application has been faced with the difficulties of dimmer compatibility due to low LED power. The LED current dimming is basically controlled by primary side regulation with feedback modulation in the proposed TRIAC dimmable driver. With system compactness and better dimmable compatibility, passive bleeder is designed to stabilize TRIAC turn-on and turn-off...
In this paper, an ohmic heater circuit is proposed using low cost, low volume, high power factor, high efficiency, and high frequency power inverters. In order to reduce switching losses while keeping operation frequency high, the well-known techniques of zero-voltage switching (ZVS) and phase shifting control are described and used. A low frequency control loop is proposed as a way of getting low...
This work presents a new multilevel unidirectional single-phase PFC rectifier topology well-suited for applications targeting for high efficiency and/or high power density. The characteristics of this rectifier topology, including the principles of operation, modulation strategy, feedback control scheme, and dimensioning equations are described in this paper. Finally, a 3 kW laboratory prototype is...
This paper presents new three-phase high power factor ac grid interface circuits appropriate for future bipolar dc active distribution networks. The ac-to-dc power converter concept is constructed by combining a six-switch buck-type PFC converter and a bipolar dc-dc boost-type inverting-link circuit. The characteristics of this concept, including an appropriate modulation and control structure, are...
This paper deals with a comparative evaluation of the single-phase “VIENNA I” and the “DBE” rectifiers. Their cores respectively involve one and two coils. They operate in continuous current and PFC modes thanks to an AC side current control. The two coils allow to get a “Double Boost Effect” during each half-period of the mains, then transmitting the stored energy to both DC capacitors. This is not...
A new control method for a single-phase PFC rectifier consisting of interleaved sub-converters is proposed. Only one current sensor is used. No conventional voltage sensors are involved. The secondary coil of the inductor in one of the two step-up sub-converters is used for PFC control. The ac-side and dc-side voltage information required for the control is easily obtained from the induced voltage...
Thyristor converters will have high reliability for large current DC power supply system used for high field magnets such as superconducting magnetic energy storage (SMES) and fusion devices. However, the thyristor converters control the DC voltage with a lagging power factor on the ac side. Especially, the lower DC voltage control requires the larger reactive power compensation. The authors carry...
This paper presents a fully digital control design for 1-phase 3 kW AC/DC converter. The centralized control system is designed and implemented on microcontroller-FPGA combination. This paper emphasizes the control design flexibility for switching mode power supplies when the programmable controller approach is used.
This work aims to present a simple strategy to build a single phase/-stage PFC converter with near unity power factor, using a NPC cell and passive elements to produce an input current with low distortion while feeding a battery cell bank with constant current. It is based on a discontinuous conduction mode technique and a standard phase-shift modulation to drive the NPC active switches. To demonstrate...
Superconducting magnetic energy storage (SMES) will be one of the feasible options for daily load leveling and power stabilization. Since the stored energy of SMES is proportional to the square of current, the rated current for superconducting coils will be selected to at least over 10 kA. Thyristor converters are very promising as a large current power conditioning system for high field magnets....
PFC controllers usually need three sensors. A digital implementation with pre-calculated duty cycles can reduce the number of sensors. The disadvantage of using pre-calculated duty cycles is that power factor is very sensitive to any non-idealities, so some kind of regulation is necessary. A single ADC and single loop technique is proposed and it obtains a high power factor under non-nominal conditions.
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