Summary
In this paper, soft switching isolated half‐bridge converter with a new active snubber cell that uses switched capacitor for renewable energy applications is proposed. The proposed snubber cell does not consist any magnetic element so that its structure is quite simple. Furthermore, the auxiliary switches in the proposed active snubber cell are exposed to only half of the input voltage. There is no additional voltage and current stress on any semiconductor devices. All semiconductor power devices in the proposed converter are operated by soft switching. The proposed converter is analyzed thoroughly, and the theoretical analyzes are affirmed by an implementation having 300‐VDC input, 20‐VDC output, 75‐W output power, and 150‐kHz switching frequency. The overall hard switching efficiency of the converter is increased from 86.4% to 92.9% by aid of the proposed soft switching snubber cell.
Here, a new active snubber cell for high-power isolated pulse-width-modulated (PWM) DC-DC converters is proposed. All semiconductor power devices in the proposed converters operate with full soft switching under a very wide load range, and they are not exposed to any voltage and current stress. The main switches turn on with zero-voltage transition (ZVT) and turn off with zero-voltage switching (ZVS). The auxiliary switches turn on with zero-current switching (ZCS) and turn off with ZVS. The theoretical analysis and design procedure for the proposed active snubber cell are carried out in detail and are verified with a half-bridge (HB) converter implementation having 20V output voltage, 50 A output current, and 80 kHz switching frequency. The overall efficiency of the HB DC-DC converter is increased from about 83% in the hard switching condition to about 90% thanks to the proposed active snubber cell.
A novel capacitor voltage-reduced bidirectional (CVRB) PWM DC-DC
buck-boost converter is presented in this study. Compared to the
conventional bidirectional buck-boost converter, the proposed converter
has a lower voltage rating filter capacitor. Accordingly, the given
converter has a lower cost and 3.3% higher power density than the
conventional buck-boost converter. Additionally, the proposed converter
is more efficient due to the direct power transfer feature. Besides, the
semiconductor switches have no extra voltage/current stress. The
theoretical analysis of the converter is made, and its mathematical
analysis is presented. The novel converter is experimentally operated in
both the buck and boost modes. The experimental waveforms are shown for
both operations. The proposed converter is operated in 100 W output
power and 20 kHz switching frequency conditions.
In this study, hybrid soft switching (HSS) DC-DC boost converter is proposed.The proposed converter operates as the conventional discontinuous conduction mode (DCM) pulse-width modulated (PWM) DC-DC boost converter at light loads. When the output power increases, the snubber cell is activated, and the converter operates as frequency controlled soft switching resonant converter. Thus, higher efficiency is obtained at high power levels. In the proposed converter, the snubber cell works with a simple on-off logic instead of PWM control. Thus, it has a quite simple structure consisting of only a switch and a snubber capacitor, and does not need an additional PWM control signal. Hence, the proposed converter has the advantages of conventional DCM PWM converters while operating with higher efficiency at higher power levels. There is no additional voltage stress on any semiconductor power devices. Theoretical analysis is verified with a laboratory application of a DC-DC boost converter having input voltage of 90 V, output voltage of 400 V and output power of 1 kW.
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