IEEE Transactions on Power Electronics, 2018
A buck-boost ac-ac converter with inverting and non-inverting operations is proposed. It compensates both the voltage sag and swell when used as a dynamic voltage restorer. Its basic switching cell is a unidirectional buck circuit, owing to which it has no shoot-through concerns. It achieves safe commutation without using RC snubbers or soft commutation strategies. Further, it can be implemented with power MOSFETs without their body diodes conducting, and for current freewheeling external diodes of good reverse recovery features can be used to minimize the reverse recovery issues and relevant loss. The detailed theoretical analysis and experimental results of a 300-W prototype converter are provided. dual-buck
- AC–AC converter
- Bipolar voltage gain
Fig 1: Proposed buck-boost ac-ac converter
EXPECTED SIMULATION RESULTS:
Fig.2. NIB operation. (a) Input and output voltages and inductor current. (b) Drain-source voltages of switches.
Fig. 3. IBB operation (buck mode). (a) Input and output voltages and inductor current. (b) Drain-source voltages of switches.
Fig. 4. IBB operation (boost mode). (a) Input and output voltages and inductor current. (b) Drain-source voltages of switches.
Fig.5. INIBB operation (non-inverting buck). (a) Input and output voltages and inductor current. (b) Drain-source voltages of switches.
Fig.6. INIBB operation (inverting buck). (a) Input and output voltages and inductor current. (b) Drain-source voltages of switches.
Fig. 7. INIBB operation (inverting boost). (a) Input and output voltages and inductor current. (b) Drain-source voltages of switches.
Fig. 8. Experimental results with partially inductive load. (a) NIB operation. (b) IBB operation.
Fig. 9. Experimental results with non-linear load in NIB operation.
Fig. 10. Experimental results of the proposed DVR.
In this paper, a novel dual buck-boost ac-ac converter is proposed. It combined the operations of non-inverting buck and inverting buck-boost converters in one structure. Similar to the buck converter, it has a non-inverting buck operation, and similar to an inverting buck-boost converter, it has an inverting buck-boost operation. In addition, it has an extra operation, in which the output voltage higher or lower than the input voltage that is in-phase or out-of-phase with the input voltage can be obtained. Thus, the proposed converter can compensate both voltage sag and swell when used in a DVR.
The basic unit of the proposed converter is a unidirectional buck circuit, therefore it has no short-circuit and open-circuit problems. It has no commutation problems, and does not require lossy snubbers and/or soft commutation strategies for operation. Further, it can utilize MOSFETs without their body diodes conducting and without reverse recovery issues and relevant losses. A detailed analysis of the proposed converter and DVR has been presented and validated by experimental results.
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Dual-Buck AC–AC Converter with Inverting and Non-Inverting Operations