E Erik Lemmen

Flexible Multilevel Converters Using Four-Switch Extended Commutation Cells

The extended commutation cell is a four-port, four-switch cell that allows bidirectional energy transport in two orthogonal directions throughout the cell. By cascading multiple cells, a multilevel converter can be constructed with a high number of levels. The voltage across each cell capacitor can be adjusted independently of the load, resulting in high flexibility in output levels. In this paper, the general theoretical analysis for this cell, including the necessary design tools, is detailed. Experimental results of a two-cell eight-level dc-ac converter are given. The outcomes are in good agreement with the analysis and simulation results.

Eight-level DC-AC converter using four-switch extended commutation cells

The extended commutation cell is a four-port, four-switch cell that allows for bidirectional energy transport in two orthogonal directions throughout the cell. By cascading multiple cells a multilevel converter can be constructed with a high number of cells. The voltage across each cell capacitor can be adjusted independently of the load, resulting in high flexibility in output levels. This paper presents the analysis, design and verification of a 4.4kW eight-level dc-ac converter. The capacitor voltage control is operated with closed loop control and the output is operating in open loop. The experimental results are in agreement with the simulations are show the cells potential for application in multilevel power converters.

Load-Current-Corrected Capacitor Voltage Control in Eight-Level DC–AC Converter Using Extended Commutation Cells

The extended commutation cell is a four-port four-switch cell that allows for bidirectional energy transport in two orthogonal directions throughout the cell. By cascading multiple cells, a multilevel converter can be constructed with a high number of levels. The voltage across each cell capacitor can be adjusted independently of the load, resulting in high flexibility in output levels. This paper presents an improved method for capacitor voltage control, based on a system model and the measured output current. The proposed method is analyzed and verified on a

Passive regenerative snubber cell applied to isolated DCM SEPIC converter

4.4\text{-}\mathrm{k}\mathrm{W}

Comparison between dissipative snubber and passive regenerative snubber cells as applied to isolated DCM SEPIC converters

eight-level dc-ac converter. The obtained reduction in capacitor voltage ripple is more than

Advances in High-Precision Amplifiers—The Extra L Opposed Current Converter

75\%

The extra L opposed current converter

.

Passive Regenerative and Dissipative Snubber Cells for Isolated SEPIC Converters: Analysis, Design, and Comparison

Isolated converter such as SEPIC has a high voltage stress in the main switch due to transformer leakage inductance. To solve this issue an active or passive clamp action is necessary. The common passive solution based on a RCD snubber is simple but impractical when the value of the leakage inductance is significant. In other hands, passive regenerative solutions generally compromise the isolation, making the search for a suitable snubber a challenge. In this paper, an effective passive regenerative snubber cell for isolated DCM SEPIC converters is presented. It is intended to improve the converter efficiency by transferring the energy stored in the transformer leakage inductance to the output. Analysis is presented in detail together with a practical design procedure. To validate the proposal, simulated and experimental results are performed for a 100 W, 100 V input and 50 V output voltage converter.

Direct waveform synthesis with continuous variable level multilevel converter using extended commutation cells

This paper presents the comparison between dissipative RCD and passive regenerative snubber cells for isolated SEPIC converters. The passive cell is intended to improve the converters efficiency by transferring the energy stored in the transformer leakage inductance to the converter output. The analysis for both snubbers are detailed including design guidelines. In order to validate the regenerative proposal and compare its feasibility, experimental verification is performed for both snubbers on a 100 W, 100 V input and 50 V output voltage SEPIC converter operating in DCM.

Sliding mode capacitor voltage control in extended commutation cell based inverter

In existing half/full-bridge high-precision amplifiers, output distortion is present due to the required switch blanking time. The OCC topology does not require this blanking time but has a much higher total inductor volume compared to the half bridge. In this paper, a patented new topology is introduced that has the advantages of the OCC but with a much lower total inductor volume. The basic operation and properties of the ELOCC topology are explained including an extended optimization of the total inductor volume and an average model for control design. A prototype ELOCC current amplifier has been developed. The behavior of this prototype is in good agreement with the obtained simulation results. Even though the prototype is not fully optimized, the linearity compared to a full bridge is already impressive.