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BLDC controller

After examining BLDC controllers available on the net (mostly for RC airplanes), I decided to design and build my own controller for robots.

Requirements

  • Sensorless
  • Max voltage: 12V
  • Max current: 10A
  • I²C for control
  • RS232 (5V) for diagnostic and configuration
  • No SMD parts
  • Minimum additional elements
  • ISP connector for programming

Controller is based on Atmel ATmega8 chip with limited number of external components. Preliminary design is finished. I will publish here all schematics, board and software.

Schematic

The early version of the schematic is available at the end of the page.

This project was never finished
I have no time to finish it nor update schematics.
Version of the schematic visible on the page has some small bugs, e.g. +5V instead of +12V for IRF2101.
Please use this BLDC controller as reference but not working unit!
For working device check links section, especially Atmel links -- Atmel provides schematics and source code for their sensorless application.

Early version of the PCB design.

EFT zero cross detection

Voltage divider with low pass filter connected to ADC inputs. ADC reference voltage equal to power voltage.

Current sensor

Voltage divider with low pass filter connected to ADC input. Designed to use with internal reference voltage 2.56V.

Low voltage sensor

Voltage divide with low pass filter connected to analog comparator. Input is compared with internal reference voltage 2.56V.

Power bridge

IRL2703 MOSFETs (TO-220AB package) controlled by IR2101 chips.

Power

7805 to provide 5V.

Other

ISP connector, RS232 (5V) connector, I2C connector. Power, program and user function LEDs.

PCB

Early prototype version of PCBs, two prototypes were made. Size 10x8cm. Needs to be optimized.

Partially assembled controller.
Assembled secondary prototype of the controller.

Links

Application notes

Semiconductors

Other Controllers

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Aquaticus_BLDC_schematic_prototype.png56.52 KB