EPE Association: NORpie 2004

NORpie 2004 - Topic 01: SMPS
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   Selection of Power Filters for Switched Mode Power Supplies
By K. S. Kostov; J. P. Sjöroos; J. Kyyrä; T. Suntio [View]
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Abstract: Power filter manufacturers provide Insertion Loss (IL) measurement data for their products. These are usually 50 §Ù / 50 §Ù and sometimes the so-called ¡°approximate worst case measurements¡±. The aim of this work is to find out which of these data should be considered when selecting an input filter for a switched mode power supply. The results show that, the actual common mode attenuation of a filter operating with a buck converter is almost same as the IL data with 0.1 §Ù / 100 §Ù source and load impedance, whereas the actual differential mode IL is approximately same as the IL data for 100 §Ù / 0.1 §Ù conditions.

   Sliding Mode Control for Half-Wave Zero Current Switching Quasi-Resonant Buck Converter
By M. Ahmed; M. Kuisma; P. Silventionen [View]
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Abstract: This paper focuses on the practical implementation of sliding mode control (SMC) in a half-wave zero current switching quasi-resonant Buck converter. SMC can manipulate efficiently the nonlinear phenomena that appear in switch mode power supplies, furthermore SMC is less affected by disturbances compared to other control techniques, and it is not operating at a constant switching frequency. Since half wave zero current switching quasi-resonant Buck converter is not operating at a constant switching frequency and it is sensitive to dynamic variation, SMC is selected in this paper as a control technique. An explanation of the implementation of SMC, and selecting its parameters is given. A detailed mathematical analysis is performed in order to select the appropriate values of the tank components elements. The tank inductor value is assumed to be small and constant, and a range of tank capacitor values is obtained. The prototype of an analog sliding mode control for the converter is constructed. In order to study the effect of SMC on the converter behavior, the system is tested in the steady state and under different load value conditions. The obtained graphs show that the performance of SMC is good, even under the worst load conditions, i.e. no load and full load.

   Analysis and Measurement of Load Effect on Converter Dynamics under Constant-Voltage and Constant-Current Control
By T. Suntio; T. Tepsa [View]
[Download]

Abstract: Dynamical behavior of a switched-mode converter under constant-voltage and constant-current control is dependent on the type of load. The transfer functions describing the converter dynamics are typically given at resistive load but the practical loads are very seldom resistive but composing of other converters upstream, storage batteries or extra capacitors, etc. The formalism to analyze the load effect may be derive using two-port unterminated modeling technique giving general and easily understandable formulas from which the load effect may be deduced. The open-loop output impedance plays a significant role either amplifying or attenuating the load effect. The analysis shows that the constant-voltage control has tendency for reduced control bandwidth, and the constant-current control for increased control bandwidth, respectively, when the load magnitude is lower than the magnitude of open-loop output impedance.

   Dynamic Analysis of a Buck Converter with Input Filter via Polynomial Representation Approach
By A. Altowati; K. Zenger; T. Suntio [View]
[Download]

Abstract: An input-output approach is applied to model and analyze DC/DC converters operating in continuous inductor current mode with voltage and peak current mode control (PCMC). The proposed method is used to study the dynamic behavior of a DC-DC buck converter with input filter. The effect of input filter on the output dynamics is studied. A further investigation of the internal behavior of the converter and input filter is carried out to improve the understanding of this interesting behavior.

NORpie 2004 - Topic 01: SMPS
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2004 > NORpie 2004 - Topic 01: SMPS
	[return to parent folder]

	Selection of Power Filters for Switched Mode Power Supplies By K. S. Kostov; J. P. Sjöroos; J. Kyyrä; T. Suntio	[View] [Download]
Abstract: Power filter manufacturers provide Insertion Loss (IL) measurement data for their products. These are usually 50 §Ù / 50 §Ù and sometimes the so-called ¡°approximate worst case measurements¡±. The aim of this work is to find out which of these data should be considered when selecting an input filter for a switched mode power supply. The results show that, the actual common mode attenuation of a filter operating with a buck converter is almost same as the IL data with 0.1 §Ù / 100 §Ù source and load impedance, whereas the actual differential mode IL is approximately same as the IL data for 100 §Ù / 0.1 §Ù conditions.

	Sliding Mode Control for Half-Wave Zero Current Switching Quasi-Resonant Buck Converter By M. Ahmed; M. Kuisma; P. Silventionen	[View] [Download]
Abstract: This paper focuses on the practical implementation of sliding mode control (SMC) in a half-wave zero current switching quasi-resonant Buck converter. SMC can manipulate efficiently the nonlinear phenomena that appear in switch mode power supplies, furthermore SMC is less affected by disturbances compared to other control techniques, and it is not operating at a constant switching frequency. Since half wave zero current switching quasi-resonant Buck converter is not operating at a constant switching frequency and it is sensitive to dynamic variation, SMC is selected in this paper as a control technique. An explanation of the implementation of SMC, and selecting its parameters is given. A detailed mathematical analysis is performed in order to select the appropriate values of the tank components elements. The tank inductor value is assumed to be small and constant, and a range of tank capacitor values is obtained. The prototype of an analog sliding mode control for the converter is constructed. In order to study the effect of SMC on the converter behavior, the system is tested in the steady state and under different load value conditions. The obtained graphs show that the performance of SMC is good, even under the worst load conditions, i.e. no load and full load.

	Analysis and Measurement of Load Effect on Converter Dynamics under Constant-Voltage and Constant-Current Control By T. Suntio; T. Tepsa	[View] [Download]
Abstract: Dynamical behavior of a switched-mode converter under constant-voltage and constant-current control is dependent on the type of load. The transfer functions describing the converter dynamics are typically given at resistive load but the practical loads are very seldom resistive but composing of other converters upstream, storage batteries or extra capacitors, etc. The formalism to analyze the load effect may be derive using two-port unterminated modeling technique giving general and easily understandable formulas from which the load effect may be deduced. The open-loop output impedance plays a significant role either amplifying or attenuating the load effect. The analysis shows that the constant-voltage control has tendency for reduced control bandwidth, and the constant-current control for increased control bandwidth, respectively, when the load magnitude is lower than the magnitude of open-loop output impedance.

	Dynamic Analysis of a Buck Converter with Input Filter via Polynomial Representation Approach By A. Altowati; K. Zenger; T. Suntio	[View] [Download]
Abstract: An input-output approach is applied to model and analyze DC/DC converters operating in continuous inductor current mode with voltage and peak current mode control (PCMC). The proposed method is used to study the dynamic behavior of a DC-DC buck converter with input filter. The effect of input filter on the output dynamics is studied. A further investigation of the internal behavior of the converter and input filter is carried out to improve the understanding of this interesting behavior.