Now a new type of application is emerging quietly, among which the four-rotor UAV is the most representative, and this kind of application is increasingly favored by amateurs. Drones are also being considered for commercial applications such as surveillance. Of particular importance to these applications is the dynamic response of the BLDC motor controller and its ability to smoothly control the BLDC motor at low speeds and without sensors.

Scalar techniques are not precise enough for dynamic load change applications. Magnetic field directional control (FOC) technology can greatly improve the accuracy, so it is widely used to drive high-end industrial AC equipment. By implementing FOC, BLDC motor can provide accurate control over drones and other high-performance applications (such as medical robots, universal systems, and autonomous driving vehicles) at reasonable cost.