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This paper presents a bi-directional quasi-Zsource inverter (qZSI) based DC/DC converter for supercapacitor (SC) interfacing in high power applications. In the SC charging mode the proposed converter acts as a conventional VSI based step-down converter, but in the energy recovery mode it acts as a qZSI-based step-up DC/DC converter. The paper analyzes and discusses the operation of the converter in the SC charging mode. The analysis of the static model of the converter as well as the Bode diagram are presented. Theoretical results are verified by experimental results on a 500 W prototype converter.

This paper proposes a new type of power converter for drive systems to enable the exchange of recuperated energy within an independent DC subgrid having one centralized energy storage element.Many industrial applications that require rapid cyclic starts and stops are subject to significant energy waste at the brake chopper of the DC bus due to over voltage during motor deceleration. The proposed solution allows the brake chopper to be eliminated and the otherwise wasted energy to be stored externally. The solution does not require identical hardware or exact synchronization between the drive rectifiers. Experimental results in industrial robotics show savings of up to 20%.

This paper presents an analysis of the continuous current and the discontinuous current mode operation of the transformer of a step-up DC/DC converter topology intended for applications with widely changing input voltages. The proposed topology consists of a LC network coupled with a single-phase inverter on the primary side and a full-bridge rectifier on the secondary side of an isolation transformer. When the input voltage is above the nominal value, the converter operates in the buck mode, but when the input voltage level is below the nominal value, the converter operates in the boost mode. I.

-Self-excitation for synchronous generator is described in the paper. The system is based on a buck converter input filter capacitor discharge through excitation winding of the generator. The buck converter is connected to the stator outputs through an uncontrollable diode rectifier, but excitation winding is used as a load. Input filter capacitor of the converter provides initial current pulse which magnetizes excitation system and produces the generator voltage increase, for this reason the capacitor is charged before self-excitation process starts.Results of the computer simulation and physical experiment are obtained and presented. These results show that the proposed self-excitation converter in conjunction with an input capacitor pre-charged from a low-power electronic generator actually magnetizes the generator excitation system therefore generator voltage and accordingly excitation current increases. Stabilization of generator output voltage occurs with a voltage surge, though its peak value slightly exceeds the reference one.The future investigation of the proposed self-excitation system may include definition of mathematical equations which describe transients in the generator's self-excitation mode and development of control methods for purpose of self-excitation process control without voltage peaks. The computer model also should be improved.