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This paper introduces a new dc-ac converter with the feature that it produces an instantaneous output voltage higher or lower than the input dc voltage without an intermediate power stage or transformers. This feature is provided by using one switching cell including two switches, two diodes, one inductor, and one capacitor on each inverter leg. Validating the theoretical analysis, a prototype was designed, built, and tested for an output rated power of 1 kW, a dc input voltage of 96Vdc, and output voltage of 110 Vrms. Furthermore, the fundamental output frequency was established at 60 Hz and the switching frequency at 20 kHz. [ABSTRACT FROM AUTHOR]

This paper presents a new three-phase step-up dc–dc converter with a three-phase high-frequency (HF) isolation transformer in an average current-mode controlled closed loop. This converter was developed for industrial applications where the dc input voltage is lower than the output voltage, for instance, in installations fed by battery units, photovoltaic arrays, or fuel cell systems. The converter's main characteristics are reduced input ripple current, step-up voltage, HF transformer, reduced output-voltage ripple due to three-pulse output current, and the presence of only three active switches connected to the same reference, this being a main advantage of this converter. By means of a specific switch modulation, the converter allows two operational regions, each one depending upon the number of switches in overlapping conditions—if there are two switches, it is called R2 region, and if there are three switches, it is called R3 region. An average current-mode control strategy is applied to input-current and output-voltage regulation. Theoretical expressions and experimental results are presented for a 6.8-kW prototype, operating in the R2 region, and for a 3.4-kW prototype, operating in the R3 region, both in continuous conduction mode. [ABSTRACT FROM PUBLISHER]

This paper proposes a bidirectional three-phase direct ac–ac converter, with only capacitors and switches in its power circuit and with its operation based on the switched-capacitor principle. The converter presents fixed gain, it keeps the frequencies of the output and input voltages equal, and it operates in open loop with constant switching frequency and duty cycle. The main advantages of the proposed converter are the absence of magnetic elements in the power circuit, the higher efficiency, the higher power density, the higher specific power, the lower cost, and the fact that it can convert ac–ac voltages within a wide frequency range, including dc voltage. Therefore, it is suitable to replace the conventional three-phase autotransformer in industrial, commercial, and residential applications, and it can be designated as a magnetic-less three-phase solid-state autotransformer. The principle of operation, a qualitative and quantitative analysis, the design methodology, and a fabricated example are described in this paper. In order to verify the converter in the laboratory, a prototype with the following characteristics was designed and fabricated: 6 kW, 1.35 kW/kg, 380/110 V, and switching frequency of 100 kHz. The measured efficiency at rated power was 96.3%, and other relevant experimental results are reported herein. [ABSTRACT FROM PUBLISHER]

This paper presents a new nonisolated buck/boost-type multilevel dc–dc converter suitable for high-power and medium/high-voltage application. The main features of the proposed topology are as follows: low voltage across the semiconductors, low switching losses, and reduced volume of the output filter. The theoretical analysis is carried out for a five-level bidirectional structure of the proposed converter, operating in Buck mode. The proposed topology presents some capacitors, and their voltage must be balanced for proper operation of the converter. Thus, a capacitor voltage balancing active control using a feedforward technique is proposed and analyzed in detail. In order to validate the theoretical analysis, a prototype with 10 kW output power capability, 1.3 kV to 800 V input-to-output voltage, and 20 kHz of switching frequency was built and experimented. The results attest the advantages of the new dc–dc topology, as well as the new capacitor voltage control technique. [ABSTRACT FROM AUTHOR]

Automotive embedded electronic systems have been increasing in power and complexity and, therefore, more advanced power electronic converters are necessary in these vehicles. Several dual-voltage (42 V/14 V) bidirectional converter architectures have been proposed for automotive systems in recent years. However, most of them have low efficiency or are based in series and parallel configurations with large number of semiconductors and magnetics devices. Therefore, in this paper, we propose a bidirectional high-efficiency converter with lower number of components. This converter was created by merging a switched-capacitor converter and a conventional bidirectional converter, resulting in a hybrid topology. The voltage across the semiconductors of the proposed converter is equal to half of the highest voltage source value. Furthermore, the topology is composed of only one inductor to control the power flow between the two voltage sources. To verify all the mentioned features, a prototype was implemented experimentally, reaching a maximum efficiency of 97.5%. [ABSTRACT FROM PUBLISHER]

This letter proposes an ac–ac converter based on the switched-capacitor principle. The new topology is described, analyzed, designed, and tested in the laboratory. The converter characteristics at the frequency of the input voltage and at the switching frequency are described herein. The absence of magnetic elements and the stress voltages in all components equal to half the input voltage are the main advantages of the proposed ac–ac converter. In order to demonstrate the performance of this converter a design example and experimental results for a prototype of 600 W, 220 Vrms high-side voltage, 110 Vrms low-side voltage, and switching frequency of 50 kHz are reported herein. The maximum and nominal efficiencies obtained were 95.6% and 90.6%, respectively. [ABSTRACT FROM PUBLISHER]