EPE Association: NORpie 2000 - Topic 08: ACTIVE RECTIFIER TOPOLOGY

NORpie 2000 - Topic 08: ACTIVE RECTIFIER TOPOLOGY
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   Input Power Quality in Matrix Converters: Minimisation of the RMS Value of Input Current Disturbances under Unbalanced and Nonsinusoidal Supply Voltages
By D. Casadei; C. Klumpner; M. Matteini; G. Serra; A. Tani [View]
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Abstract: In this paper two input current modulation strategies for matrix converters are experimentally analyzed under two different supply conditions: sinusoidal unbalanced voltages and nonsinusoidal balanced voltages. Both strategies use the Space Vector Modulation (SVM) technique in order to control the matrix converter accordingly to the input and output constraints. Strategy A modulates the input currents keeping the corresponding space vector in phase with the input voltage vector. Strategy B operates in order to keep the input current vector in phase with the positive sequence fundamental component of the input voltage vector. A comparison between the two strategies is made in terms of reduction of the input current disturbances due to voltage non idealities present on the grid. It is concluded that a dynamic current modulation strategy, independent of the voltage disturbances such as Strategy B, is more effective for the reduction of the RMS value of input current disturbances. The validity of the theoretical investigation and the effectiveness of the current modulation strategy have been confirmed by experimental tests carried out on a matrix converter prototype.

   A Novel Concept for Transformer Volt Second Balancing of a VIENNA Rectifier III Based on Direct Magnetizing Current Measurement
By Franz Stögerer; Johann W. Kolar; Uwe Drofenik [View]
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Abstract: For a VIENNA Rectifier III different turn-on and turn-off delay times of the power transistors and different on-state voltages of the valves would cause an unbalance of the positive and negative volt seconds applied to the high frequency transformer within a pulse period and/or result in transformer saturation without additional measures. This paper proposes a novel concept for actively ensuring a symmetric magnetization with switching frequency of the transformer magnetic core of a VIENNA Rectifier III based on direct measurement of the magnetizing current. The magnetizing current is determined by subtraction of the transformer primary and the secondary currents being weighted according to the transformer turns ratio. The subtraction is realized by magnetic compensation employing a through-hole DC current transducer. A deviation from a symmetric magnetization within a pulse period is detected and used by a controller for closed-loop balancing of the volt seconds applied to the transformer primary in order to eliminate an existing asymmetry. The controller is designed based on sampled data system theory. The theoretical considerations and the controller dimensioning are verified by experimental results gained from a 8.5kW prototype of the VIENNA Rectifier III.

   Half-Voltage DC Output Type Three-Phase Double Diode Rectifiers with 12/24-Step Input Voltages
By Kuniomi Oguchi; Tsuguhiro Tanaka; Nobukazu Hoshi; Tomotsugu Kubota; Kenichi Sakakibara [View]
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Abstract: Novel three-phase rectifiers with half-voltage DC outputs are presented. The proposed system consists of double diode bridge circuits with additional switches and three-phase transformers with a rating of around 50% power capacity of the DC output power. The rectifier can generate 24-step input voltages with a total harmonic distortion of 7.8% and result nearly sinusoidal input currents.

NORpie 2000 - Topic 08: ACTIVE RECTIFIER TOPOLOGY
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2000 > NORpie 2000 - Topic 08: ACTIVE RECTIFIER TOPOLOGY
	[return to parent folder]

	Input Power Quality in Matrix Converters: Minimisation of the RMS Value of Input Current Disturbances under Unbalanced and Nonsinusoidal Supply Voltages By D. Casadei; C. Klumpner; M. Matteini; G. Serra; A. Tani	[View] [Download]
Abstract: In this paper two input current modulation strategies for matrix converters are experimentally analyzed under two different supply conditions: sinusoidal unbalanced voltages and nonsinusoidal balanced voltages. Both strategies use the Space Vector Modulation (SVM) technique in order to control the matrix converter accordingly to the input and output constraints. Strategy A modulates the input currents keeping the corresponding space vector in phase with the input voltage vector. Strategy B operates in order to keep the input current vector in phase with the positive sequence fundamental component of the input voltage vector. A comparison between the two strategies is made in terms of reduction of the input current disturbances due to voltage non idealities present on the grid. It is concluded that a dynamic current modulation strategy, independent of the voltage disturbances such as Strategy B, is more effective for the reduction of the RMS value of input current disturbances. The validity of the theoretical investigation and the effectiveness of the current modulation strategy have been confirmed by experimental tests carried out on a matrix converter prototype.

	A Novel Concept for Transformer Volt Second Balancing of a VIENNA Rectifier III Based on Direct Magnetizing Current Measurement By Franz Stögerer; Johann W. Kolar; Uwe Drofenik	[View] [Download]
Abstract: For a VIENNA Rectifier III different turn-on and turn-off delay times of the power transistors and different on-state voltages of the valves would cause an unbalance of the positive and negative volt seconds applied to the high frequency transformer within a pulse period and/or result in transformer saturation without additional measures. This paper proposes a novel concept for actively ensuring a symmetric magnetization with switching frequency of the transformer magnetic core of a VIENNA Rectifier III based on direct measurement of the magnetizing current. The magnetizing current is determined by subtraction of the transformer primary and the secondary currents being weighted according to the transformer turns ratio. The subtraction is realized by magnetic compensation employing a through-hole DC current transducer. A deviation from a symmetric magnetization within a pulse period is detected and used by a controller for closed-loop balancing of the volt seconds applied to the transformer primary in order to eliminate an existing asymmetry. The controller is designed based on sampled data system theory. The theoretical considerations and the controller dimensioning are verified by experimental results gained from a 8.5kW prototype of the VIENNA Rectifier III.

	Half-Voltage DC Output Type Three-Phase Double Diode Rectifiers with 12/24-Step Input Voltages By Kuniomi Oguchi; Tsuguhiro Tanaka; Nobukazu Hoshi; Tomotsugu Kubota; Kenichi Sakakibara	[View] [Download]
Abstract: Novel three-phase rectifiers with half-voltage DC outputs are presented. The proposed system consists of double diode bridge circuits with additional switches and three-phase transformers with a rating of around 50% power capacity of the DC output power. The rectifier can generate 24-step input voltages with a total harmonic distortion of 7.8% and result nearly sinusoidal input currents.