This paper proposes a new converter using matrix converter theories and Z -source conversion concepts and illustrates its application for the integrated starter/alternator (ISA) system by a case study. The problem imposed by the traditional voltage source inverter to develop the relatively high dc voltage from the relatively low ac voltages of an ac machine in the ISA system has been addressed in this paper. The proposed converter achieved boost mode dc-ac inversion and buck mode ac-dc rectification, hence allowing the peak voltage of the ac motor to exceed the dc source voltage substantially. In the rectification mode, it can achieve the regulated output dc voltage with variable-voltage-variable-frequency ac source without extra close-loop control or large energy-storage devices. This paper investigates the quadrant operation of the converter, its control, its steady-state performance, and experimental verification.