Two-stage power conversion architecture for an LED driver circuit

IEEE Trans. Power Electron.

Otten

Perreault

2016

Self Cite

Abstract-This paper presents a novel ac-dc power factor correction (PFC) power conversion architecture for single-phase grid interface. The proposed architecture has significant advantages for achieving high efficiency, good power factor, and converter miniaturization, especially in low-to-medium power applications. The architecture enables twice-line-frequency energy to be buffered at high voltage with a large voltage swing, enabling reduction in the energy buffer capacitor size, and elimination of electrolytic capacitors. While this architecture can be beneficial with a variety of converter topologies, it is especially suited for system miniaturization by enabling designs that operate at high frequency (HF, 3 -30 MHz). Moreover, we introduce circuit implementations that provide efficient operation in this range. The proposed approach is demonstrated for an LED driver converter operating at a (variable) HF switching frequency (3 -10 MHz) from 120 Vac, and supplying a 35 V dc output at up to 30 W. The prototype converter achieves high efficiency (92 %) and power factor (0.89), and maintains good performance over a wide load range. Owing to architecture and HF operation, the prototype achieves a high 'box' power density of 50 W / in 3 ('displacement' power density of 130 W / in 3 ), with miniaturized inductors, ceramic energy buffer capacitors, and a small-volume EMI filter.

Section: Proposed System Architecturementioning

confidence: 99%

New AC–DC Power Factor Correction Architecture Suitable for High-Frequency Operation

IEEE Trans. Power Electron.

Otten

Perreault

2016

Self Cite

“…Many converter topologies can be considered as a regulating converter of the proposed architecture. For example, as described later, the regulating converters may be very effectively implemented using resonant-transition discontinuous-mode inverted buck converters [14]. This topology enables high-frequency operation of the regulating converters (3-30 MHz) with high efficiency, low device voltage stress, small component size, and good control capability.…”

Section: System Architecture and Characteristicsmentioning

confidence: 99%

“…10. The regulating converter is designed with single switch, diode, and small inductor, and operates at HF (3-30 MHz) similar to the regulation-stage design illustrated in [13], [14]. It is an "inverted" circuit in the sense that it is designed with "common positives."…”

Section: A Topololgy Selectionmentioning

confidence: 99%

“…The currents drawn by the (at least) two regulating converters are modulated to draw energy from the capacitors, such that the currents drawn from the capacitor stack results in an input current waveform to the rectifier that provide both high power factor and the total needed energy transfer to support the output. Because the regulating converters operate from voltages that are much smaller than the total line voltage, they can be designed to switch at much higher frequencies and can be operated at smaller characteristic impedance levels than could a single converter rated at line voltage (e.g., as described in [13] [14]). Many converter topologies can be considered as a regulating converter of the proposed architecture.…”

Section: System Architecture and Characteristicsmentioning

confidence: 99%

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Power conversion architecture for grid interface at high switching frequency

2014 IEEE Applied Power Electronics Conference and Exposition - APEC 2014

Otten

2014

Self Cite

Abstract-This paper presents a new power conversion architecture for single-phase grid interface. The proposed architecture is suitable for realizing miniaturized ac-dc converters operating at high frequencies (HF, above 3 MHz) and high power factor, without the need for electrolytic capacitors. It comprises of a line-frequency rectifier, a stack of capacitors, a set of regulating converters, and a power combining converter (or set of power combining converters). The regulating converters have inputs connected to capacitors on the capacitor stack, and provide regulated outputs while also achieving high power factor, with twice-line-frequency energy buffered on the capacitor stack. The power combining converter combines power from the individual regulated outputs to a single output, and may also provide isolation. While this architecture can be utilized with a variety of circuit topologies, it is especially suited for systems operating at HF (above 3 MHz), and we introduce circuit implementations that enable efficient operation in this range. The proposed approach is demonstrated for an LED driver operating from 120 Vac, and supplying a 35 V , 30 W output. The prototype converter operates at a (variable) switching frequency of 5-10 MHz and an efficiency of > 93%. The converter achieves a displacement power density of 130 W/in 3 , while providing a 0.89 power factor, without the use of electrolytic capacitors.

“…Because the regulating converters operate from voltages that are much smaller than the total line voltage, they can be designed to switch at much higher frequencies than conventionally used for converter miniaturization (e.g., as described in [12] [24]). Among many regulating converter topology options, the resonant-transition inverted buck converter can be very effectively utilized [24]. This topology enables converter miniaturization with high-frequency operation (3 -10 MHz), high efficiency, low device voltage stress, small component size, and good control capability without the need for a current sensor..…”

Section: Stacked Ac-dc Converter Architecturementioning

confidence: 99%

High-frequency isolated ac-dc converter with stacked architecture

2017 IEEE Applied Power Electronics Conference and Exposition (APEC)

Bandyopadhyay

Perreault

2017

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Abstract-This paper presents a new isolated ac-dc power converter achieving both high power factor and converter miniaturization suitable for many low power ac-dc applications. The proposed ac-dc converter architecture comprises a line-frequency rectifier, a stack of capacitors, a set of regulating converters, and a multi-input isolated bus converter. Among many suitable circuit implementations, the prototype system utilizes the resonanttransition buck converter as a regulating converter, and the capacitively-aided isolated bus converter for the isolated bus converter. The converter is miniaturized by operating at high frequency (1 -10 MHz range), and it buffers the ac-line frequency energy with a pair of stacked ceramic capacitors (1 µF and 150 µF, 100 V rating) without a requirement for electrolytic capacitors. The prototype converter is implemented to operate from 120 Vac to 12 V, and up to 50 W output as an example isolated ac-dc converter for power supply applications. The prototype converter demonstrates with 88 % efficiency and 0.86 power factor, and provides 50 W/in 3 power density, which is five times higher than the power density of typical conventional designs.