tailieunhanh - Power Quality Harmonics Analysis and Real Measurements Data Part 8

Tham khảo tài liệu 'power quality harmonics analysis and real measurements data part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Study of LCC Resonant Transistor DC DC Converter with Capacitive Output Filter 129 From fig. 11-b and fig. 12-b the difference between the main and the boundary operation mode of the converter can be seen. In the first case the commutations in the rectifier the process of recharging the capacitor C0 end before the commutations in the inverter the process of recharging the capacitor cs . In the second case the commutations in the rectifier complete after the ones in the inverter. In both cases during the commutations in the rectifier all of its diodes are closed and the output current io is equal to zero fig. 11-c and fig. 12-c . Fig. 12-b confirms the fact that at certain conditions the output voltage can become higher than the power supply voltage without using a matching transformer. At no-load mode the converter operation is shown in fig. 13. In this case the output voltage is more than two times higher than the power supply one. ua 500V div ub 500V div x 5ps div Fig. 13. Oscillograms illustrating no-load mode of the converter 8. Conclusions The operation of an LCC transistor resonant DC DC converter with a capacitive output filter and working above the resonant frequency has been investigated taking into account the influence of snubber capacitors and a matching transformer. The particular operation modes of the converter have been considered and the conditions under which they are obtained have been described. The output characteristics for all operation modes of the converter have been built including at regulation by means of changing the operating frequency. The boundary curves between the different operation modes of the converter as well as the area of natural commutation of the controllable switches have been shown in the plane of the output characteristics. Results from investigations carried out by means of a laboratory prototype of the converter have been obtained and these results confirm the ones from the analysis. The theoretical investigations .