A novel AC — DC machine is invented on the basis of the proposed new idea of electric power integration, wherein the stator with one set of 3-phase AC winding and another set of 12-phase DC winding, together with a rotor having a d-axis field winding and a q-axis stabilizing winding, is combined with a 12-phase bridge rectifier, an AC exciter with an excitation system, the automatic voltage regulator as well as a cooling system to form an integral whole. Simultaneous AC and DC power supplies with high quality being available, this new generator is especially suitable for self-contained electrical systems, such as those found on aircraft and ships, where good performance and compact size are essential. Mathematical models of the machine are established and calculation and measurement methods of the model parameters are proposed, providing a theoretical basis for solving the key technical problems. Low-frequency oscillations occurring in a synchronous generator-rectifier system are examined, stability criterion of the system is obtained, and technical measures are proposed to ensure system’s stable operation. With the AC voltage regulated, the DC voltage floats within an acceptable range, which can be achieved through rational machine design. Due to complete electrical separation of the AC and DC circuits and usage of the properly designed 12-phase DC winding, the AC voltage distortion caused by DC commutation and the DC voltage pulsation are greatly reduced, which considerably improves the EMC of the system. Expressions for the peak current and impact torque following a short-circuit fault at DC side or at both AC and DC sides are derived once the strong nonlinearity of the system is ingeniously handled. The principle and methods for on-line real time fault diagnosis of the diodes in the 12-phase rectifier are proposed so that the state of each diode can be easily judged according to the input/output-voltage waveforms. Based on the achievements of above research, AC - DC generators with high performance have been developed, laying the foundation for integration of self-contained electrical systems.