Series Hybrid Vehicle Control Method and Series Hybrid Vehicle

A series hybrid vehicle control method controls a series hybrid vehicle including a power generation system that generates electric power by driving an electric generator with an internal combustion engine. A control unit is configured to, in a case where a failure occurs in the power generation system, limit a torque of the internal combustion engine, set an engine rotation speed at which power generation efficiency of the electric generator is maximized within a range in which the torque is limited, and control the internal combustion engine based on the engine rotation speed.