The present application provides a control method, an apparatus, a power system, and an electric vehicle, relating to the field of electric vehicles. The method includes: obtaining a battery cell temperature of a power battery, and sending a first control signal to an inverter when the battery cell temperature meets a preset power battery heating condition, where the first control signal is configured to control the inverter to convert a current provided by the power battery into an alternating current with a randomly changing frequency, and the alternating current with a randomly changing frequency is configured to supply power to a permanent magnet motor. New frequency components may be introduced to evenly distribute originally concentrated radial electromagnetic forces to an entire stator, thereby reducing vibration noises during the heating process of the power battery.