BLDC - Electronic speed controller
Electronic speed controller for bldc machines
Project Overview
The objective of this project was to design and develop an extremely compact Electronic Speed Controller (ESC) for drone propulsion systems.
The primary goals were size optimization, high efficiency, and flexible motor-control capability, suitable for integration into lightweight aerial platforms.
Technical Concept
The ESC architecture was based on three half-bridge stages using high-performance Power MOSFETs to minimize conduction and switching losses.
An Infineon gate driver IC with an integrated charge pump was selected to drive the bridge transistors efficiently, ensuring stable high-side switching without additional bootstrap components.
The control logic was implemented on an STM32 microcontroller, chosen for its computational performance, PWM precision, and integrated ADC features.
Implementation
- PCB Design: The complete system was implemented on a custom multi-layer PCB with a highly compact layout utilizing 0402 SMD components to minimize footprint and parasitics.
- Assembly: Component placement and soldering were performed manually by the project team, demonstrating precision assembly and rework capabilities for fine-pitch devices.
- Control Strategy:
- Initial prototype operated using six-step commutation control, verified on a three-phase BLDC motor test setup.
- Subsequent firmware iterations implemented Field-Oriented Control (FOC) to achieve smoother torque generation, higher efficiency, and reduced acoustic noise.
Results
The final prototype successfully demonstrated:
- Stable operation of the three-phase inverter stage
- Reliable gate drive using the integrated Infineon charge-pump driver
- Smooth transition from six-step to FOC control
- Compact mechanical footprint optimized for drone integration
The project validated the complete design workflow — from schematic development and PCB layout to firmware implementation and hardware testing — highlighting the feasibility of miniaturized ESC systems for UAV applications.
Key Features
| Parameter | Description |
|---|---|
| Microcontroller | STM32 series (ARM Cortex-M) |
| Gate Driver | Infineon IC with integrated charge pump |
| Power Stage | N-channel Power MOSFET half-bridges |
| Control Algorithms | Six-Step Commutation, Field-Oriented Control (FOC) |
| PCB Technology | Compact multi-layer design with 0402 components |
| Assembly | Hand-assembled and verified prototype |
Learnings
This project strengthened expertise in power electronics, PCB miniaturization, and motor-control algorithms.
It also underlined the importance of precision layout practices, component selection, and control-loop tuning for reliable high-frequency inverter operation.
By integrating mechanical, electrical, and software disciplines into one compact system, this ESC project embodies the full engineering development cycle — from concept to working prototype.