How to design an ESC module for drone motor control

The ability to control the motors’ speed and rotation is the design key of drones, making the electronic speed control (ESC) module an added value and a fundamental part of a drone. In this article, we will look at the key elements to consider when designing an ESC module and the market’s development solutions. The design of an ESC requires a careful evaluation and analysis of characteristics that can be summarized as follows:

  • Battery installed ON the drone;
  • Motors: The ESC module must be able to handle the amps needed for the motor to run smoothly, supported by the appropriately sized battery;
  • Propeller: Your choice of the propeller will also set up the power of your ESC. Will your drone run 3-, 4-, 5- or 6-inch propellers? What kind of performance would you like, and therefore what type of propeller pitch will you use?
  • voltage: Choose the DC/DC converter configuration to power the ESC correctly.
  • Firmware: ESCs receive an acceleration signal from the flight controller. An electronic speed drone controller uses on-board MCUs and therefore requires firmware to control the hardware.
  • Dimensions and weight, and available budget;

The use of drones is growing steadily, and applications range from the commercial to the military sector. Most drones are powered by brushless DC motors, which require appropriate and constant regulation of both speed and direction of rotation. An ESC module performs these functions and includes a power supply stage, a current-sensing circuit, a microcontroller, and a communication interface with the flight control system.

Drones must have a high level of stability and efficiency to be able to perform the applications for which they were designed successfully; this allows them to operate even in the most critical and adverse weather conditions. In the specific case of drones driven by electric motors and powered by batteries (by far the most common solution, leaving the military sector aside, of course), the longest possible operation period must be ensured for each full battery pack charge.

One of the main advantages of drones is that they can be operated remotely, flying over areas that would be too difficult, dangerous, or uncomfortable to reach by a person. Commercial applications include agriculture, plant and building monitoring (security, video surveillance, and prevention), and even the delivery of parcels, medicines, or other essential goods. Many believe that the introduction of drones has been a revolution and the effects will become even more evident in the coming years. Large companies such as Amazon and Facebook have been betting on the enormous potential offered by drones from the outset, developing programs in which unmanned aerial vehicles (UAVs) are used to deliver products and provide internet connectivity in remote and inaccessible locations, respectively.

How to design an ESC module for drone motor control

Block diagram of field-oriented control (Source: Mathworks)

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