Abstract: The present invention relates to a frequency-stable low-dielectric microwave dielectric ceramic material and a preparation method thereof. The material is prepared from the following components in percentage by mass: 70-90% of a main-phase ceramic material A, 10-30% of an auxiliary-phase ceramic material B and 0-1.0% of an oxide sintering aid C. The main-phase ceramic material A is MgxMeySiO2+x+y; the auxiliary-phase ceramic material B is composed of ?RO-bRe2O3-cTiO2, R is at least one of Ca or Sr, Re2O3 is at least two of Sm2O3, Nd2O3, Y2O3, Al2O3 and La2O3; and the oxide sintering aid C is at least one of MnO2, WO3 and CeO2.

Abstract: A topology structure of a power battery pack for a diesel-electric hybrid locomotive includes a plurality of components. A chopper unit is connected in parallel to a support capacitor, an AC/DC module, a DC/AC module, a reactor unit and a power battery system. The power battery system includes several groups of power modules. The power module includes a contactor unit, a current sensor, a fuse, a power battery, and a voltage sensor. The contactor unit, the current sensor and the power battery are connected in series. Two ends of the voltage sensor are respectively disposed at two ends of the power battery. A locomotive microcomputer is connected to a DUC controller and a power battery management system. The DUC controller is connected to the DC/AC module, the chopper unit and the contactor unit. The power battery management system is connected to the contactor unit.