Parallel resonant PMSG systems, which consist of a diesel engine, a PMSG with a resonant parallel capacitor, and a diode full-wave rectifier, are expected to be applied to series hybrid vehicle traction systems due to their high efficiency and low cost. In general, the power generation of a series of hybrid vehicle traction systems is controlled using a PWM converter. However, the power generation of the parallel resonant PMSG hybrid traction system cannot be adjusted using a PWM converter, and a new power-generation control method is required. However, the appropriate power generation control method from the point of view of battery deterioration, the number of engine starts, and fuel economy have not yet been clarified. Therefore, this paper proposes a power generation control method for parallel resonant PMSG systems applied to series hybrid vehicle traction systems.