EPE Association: EPE 2007 - Subtopic 06-4 - LS: Converter control sets and modulation strategies III

EPE 2007 - Subtopic 06-4 - LS: Converter control sets and modulation strategies III
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 06: 'Modulation strategies and specific control methods for static converter' > EPE 2007 - Subtopic 06-4 - LS: Converter control sets and modulation strategies III

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   Digitally Controlled Point of Load Converter with Very Fast Transient Response
By ANDERSEN M. A. E.; JAKOBSEN Lars T. [View]
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Abstract: This paper presents a new Digital Self-Oscillating Modulator (DiSOM) that allows the duty cycle to be changed instantly. The DiSOM modulator is shown to have variable switching that is a function of the duty cycle. Compared to a more traditional digital PWM modulator based on a counter and comparator the DiSOM modulator allows the sampling frequency of the output voltage control loop to be higher than the switching frequency of the power converter, typically a DC/DC converter. The features of the DiSOM modulator makes it possible to design a digitally controlled DC/DC converter with linear voltage mode control and very fast transient response. The DiSOM modulator is combined with a digital PID compensator algorithm is implemented in a hybrid CPLD/FPGA and is used to control a synchronous Buck converter, which is used in typical Point of Load applications. The computational time is only three clock cycles from the time the A/D converter result is read by the control algorithm to the time the duty cycle command is updated. A typical POL converter has been built and the experimental results show that the transient response of the converter is very fast. The output voltage overshoot is only 2.5\% of the nominal output voltage when a load step of 50\% - 100\% of nominal output current is applied to the converter. The settling time is approximately 8 PWM cycles.

   Experimental Comparison of Three-Phase Distributed Generation Systems Based on VOC and DPC Control Techniques
By GIGLIA Graziella; PUCCI Marcello; SERPORTA Calogero; VITALE Gianpaolo [View]
[Download]

Abstract: This paper presents an experimental comparison of VOC and DPC techniques, but focuses the attention to their behaviours when used in generating mode, e.g. for grid connected distributed generation systems from renewable sources. A test set-up has been built for the experimental assessment of the methodologies. VOC and DPC have been compared from the point of view of the dynamic performances, the harmonic content of the currents injected into the grid, their THDs and finally the efficiency and average power factor of the energy conversion at different levels of generated power.

   Multi-Dimensional Space Vector Pulse Width Modulation for Disturbance-Free Operation of a Five-Phase AC Motor Drive
By DURAN Mario J.; TORAL Sergio; BARRERO Federico; LEVI Emil [View]
[Download]

Abstract: One of the advantages of multi-phase machine variable-speed drives is the possibility of disturbance-free mode of operation when one or more phases are lost during normal operation. This requires the modification of the control algorithm in post-fault operation. This paper investigates the use of multidimensional space vector PWM technique to synthesise required voltages for the disturbance-free mode of operation of a five-phase machine in post-fault operation. Different cases, with regard to the number and spatial position of faulted phases, are covered, showing the necessary conditions mathematically and enabling examination of the performance of the modulation technique. Simulation results confirm the adequacy of the multi-dimensional PWM approach to control the supply of the machine in the post-fault mode of operation.

EPE 2007 - Subtopic 06-4 - LS: Converter control sets and modulation strategies III
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 06: 'Modulation strategies and specific control methods for static converter' > EPE 2007 - Subtopic 06-4 - LS: Converter control sets and modulation strategies III
	[return to parent folder]

	Digitally Controlled Point of Load Converter with Very Fast Transient Response By ANDERSEN M. A. E.; JAKOBSEN Lars T.	[View] [Download]
Abstract: This paper presents a new Digital Self-Oscillating Modulator (DiSOM) that allows the duty cycle to be changed instantly. The DiSOM modulator is shown to have variable switching that is a function of the duty cycle. Compared to a more traditional digital PWM modulator based on a counter and comparator the DiSOM modulator allows the sampling frequency of the output voltage control loop to be higher than the switching frequency of the power converter, typically a DC/DC converter. The features of the DiSOM modulator makes it possible to design a digitally controlled DC/DC converter with linear voltage mode control and very fast transient response. The DiSOM modulator is combined with a digital PID compensator algorithm is implemented in a hybrid CPLD/FPGA and is used to control a synchronous Buck converter, which is used in typical Point of Load applications. The computational time is only three clock cycles from the time the A/D converter result is read by the control algorithm to the time the duty cycle command is updated. A typical POL converter has been built and the experimental results show that the transient response of the converter is very fast. The output voltage overshoot is only 2.5\% of the nominal output voltage when a load step of 50\% - 100\% of nominal output current is applied to the converter. The settling time is approximately 8 PWM cycles.

	Experimental Comparison of Three-Phase Distributed Generation Systems Based on VOC and DPC Control Techniques By GIGLIA Graziella; PUCCI Marcello; SERPORTA Calogero; VITALE Gianpaolo	[View] [Download]
Abstract: This paper presents an experimental comparison of VOC and DPC techniques, but focuses the attention to their behaviours when used in generating mode, e.g. for grid connected distributed generation systems from renewable sources. A test set-up has been built for the experimental assessment of the methodologies. VOC and DPC have been compared from the point of view of the dynamic performances, the harmonic content of the currents injected into the grid, their THDs and finally the efficiency and average power factor of the energy conversion at different levels of generated power.

	Multi-Dimensional Space Vector Pulse Width Modulation for Disturbance-Free Operation of a Five-Phase AC Motor Drive By DURAN Mario J.; TORAL Sergio; BARRERO Federico; LEVI Emil	[View] [Download]
Abstract: One of the advantages of multi-phase machine variable-speed drives is the possibility of disturbance-free mode of operation when one or more phases are lost during normal operation. This requires the modification of the control algorithm in post-fault operation. This paper investigates the use of multidimensional space vector PWM technique to synthesise required voltages for the disturbance-free mode of operation of a five-phase machine in post-fault operation. Different cases, with regard to the number and spatial position of faulted phases, are covered, showing the necessary conditions mathematically and enabling examination of the performance of the modulation technique. Simulation results confirm the adequacy of the multi-dimensional PWM approach to control the supply of the machine in the post-fault mode of operation.