EPE Association: EPE 2001 - Topic 03b: DC Power Supplies

EPE 2001 - Topic 03b: DC Power Supplies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2001 - Conference > EPE 2001 - Topic 03: POWER SUPPLIES > EPE 2001 - Topic 03b: DC Power Supplies

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   A New Piezoelectric Transformer Control for an AC/DC Converter
By F.Nuño; J.Díaz; J.A.Martín; M.J.Prieto [View]
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Abstract: During the last years, a clear trend to miniaturise AC/DC adapters for portable terminals has been detected world-wide. This could be possible by replacing the classical transformer, built with commercial magnetic cores that not only limit the miniaturisation of the converter but are also EMI sources, by an alternative piezoelectric transformer, which features low profile, high power density (several times higher than high frequency magnetic ones) and low EMI generation. Due to the PT behavior, very frequency-dependent, previous works presented frequency modulation to control the output voltage like the most natural way. Also PWM control techniques can be employed in combination with the frequency control to achieve both line and load regulation. In this paper, a new control strategy is introduced that can be used with PT-based converters. It can simplify the control design process and only a few components are necessary. The switches in the power stage are so operated that a constant-frequency, constant duty-cycle voltage waveform is applied to the input of the PT. The response of the component to this waveform originates an output voltage that builds up to a maximum allowable value. When this value is reached, the control circuit detects this situation and stops driving the switches. The PT input is zero and the output voltage is pulled down until a minimum allowable value is reached. At this point the control circuit activates the switches again and the cycle starts anew. This hysteretic control is well-known and employed in low standbypower SMPS but never for a PT control. The main features of this control are presented in the paper. In any case, Piezoelectric Transformers are not yet usual devices in power electronics converters, only a few companies develop this kind of elements and several limitations have been detected along this work.

   A Non-Linear Control applied to the HBCC Converter
By J. M. Guerrero; L. García de Vicuña; J. Matas; M. Castilla [View]
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Abstract: In this paper a large-signal model for the Half-Bridge Complementary-Control (HBCC) converter is presented in order to deduce a non-linear control for this conversion structure. The procedure proposed allows to obtain a fast controller that provides both tight regulation and a robust voltage response against input voltage and load disturbances.

   An Active Circuit to Symmetrical Power Supply Control
By N.L. Montes Jr; C.A. Bissochi Jr; R.S.F. Vincenzi; A.A. Coelho Ernane; L.H.S.C. Barreto [View]
[Download]

Abstract: This paper presents a controlled symmetrical power supply. While feeding unbalanced loads, the converter will operate in the switching mode, and the circuit will only process the energy necessary to balance the output voltages. Switches conduction losses depends on how unbalanced the loads are.

   Improvement In Voltage Regulation & Cs With Droop Function
By E. Dallago; M. Passoni [View]
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Abstract: In this work voltage regulation with the droop function for low-voltage (LV), high-current (HC) applications is analyzed. A new dynamic analysis of the droop function gives a simple criterion for its sizing and a useful expression of the output impedance. The results are also applied to a two-phase converter with droop current sharing to evaluate both static and dynamic performance. Experimental results WM confirm theoretical predictions.

EPE 2001 - Topic 03b: DC Power Supplies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2001 - Conference > EPE 2001 - Topic 03: POWER SUPPLIES > EPE 2001 - Topic 03b: DC Power Supplies
	[return to parent folder]

	A New Piezoelectric Transformer Control for an AC/DC Converter By F.Nuño; J.Díaz; J.A.Martín; M.J.Prieto	[View] [Download]
Abstract: During the last years, a clear trend to miniaturise AC/DC adapters for portable terminals has been detected world-wide. This could be possible by replacing the classical transformer, built with commercial magnetic cores that not only limit the miniaturisation of the converter but are also EMI sources, by an alternative piezoelectric transformer, which features low profile, high power density (several times higher than high frequency magnetic ones) and low EMI generation. Due to the PT behavior, very frequency-dependent, previous works presented frequency modulation to control the output voltage like the most natural way. Also PWM control techniques can be employed in combination with the frequency control to achieve both line and load regulation. In this paper, a new control strategy is introduced that can be used with PT-based converters. It can simplify the control design process and only a few components are necessary. The switches in the power stage are so operated that a constant-frequency, constant duty-cycle voltage waveform is applied to the input of the PT. The response of the component to this waveform originates an output voltage that builds up to a maximum allowable value. When this value is reached, the control circuit detects this situation and stops driving the switches. The PT input is zero and the output voltage is pulled down until a minimum allowable value is reached. At this point the control circuit activates the switches again and the cycle starts anew. This hysteretic control is well-known and employed in low standbypower SMPS but never for a PT control. The main features of this control are presented in the paper. In any case, Piezoelectric Transformers are not yet usual devices in power electronics converters, only a few companies develop this kind of elements and several limitations have been detected along this work.

	A Non-Linear Control applied to the HBCC Converter By J. M. Guerrero; L. García de Vicuña; J. Matas; M. Castilla	[View] [Download]
Abstract: In this paper a large-signal model for the Half-Bridge Complementary-Control (HBCC) converter is presented in order to deduce a non-linear control for this conversion structure. The procedure proposed allows to obtain a fast controller that provides both tight regulation and a robust voltage response against input voltage and load disturbances.

	An Active Circuit to Symmetrical Power Supply Control By N.L. Montes Jr; C.A. Bissochi Jr; R.S.F. Vincenzi; A.A. Coelho Ernane; L.H.S.C. Barreto	[View] [Download]
Abstract: This paper presents a controlled symmetrical power supply. While feeding unbalanced loads, the converter will operate in the switching mode, and the circuit will only process the energy necessary to balance the output voltages. Switches conduction losses depends on how unbalanced the loads are.

	Improvement In Voltage Regulation & Cs With Droop Function By E. Dallago; M. Passoni	[View] [Download]
Abstract: In this work voltage regulation with the droop function for low-voltage (LV), high-current (HC) applications is analyzed. A new dynamic analysis of the droop function gives a simple criterion for its sizing and a useful expression of the output impedance. The results are also applied to a two-phase converter with droop current sharing to evaluate both static and dynamic performance. Experimental results WM confirm theoretical predictions.