| The main circuit of SS4 electrical locomotive 110V direct current source is half controlled commutated circuit and the power device is GTO, which has the limitations such as low power factor, big impact on power net, not convenient to maintenance and low reliability for so many devices, high gross weight and big volume. This paper designs a high frequency switching electrical source with IGBT on the condition of high input voltage (396V) of electrical locomotive single phase, wide range (+25%~-30%) and high output power (5500). The main circuit is parallel connected by two DC-DC converters; what's more, soft switching technique is adopted. Each device is designed and parameters are selected of the system, the power factor correction circuit and main circuit of DC-DC converter is designed. The control circuit is made up by UC3854 and UC3879 and the equilibration of load current is designed by UC3907.The topology structure of combination style of switching power is elaborated; control method of switching power is also discussed and the drive characteristics of GTO and IGBT are also introduced. The working process of full bridge ZVZCS-PWM with cushion capacitance in transform second side is introduced in detail; the realization of soft switching is discussed further. The feasibility of the designed soft switching converter is proved by simulation. The current harmonic of switching power is calculated and analyzed and the sourced power factor correction circuit is designed, too. The most excellent combined main circuit is chose to design a highly credible switching power.
|
PDF Full Text Request