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Depending on the cost and performance of the board, it may be integrated elsewhere. Design target parameters are also being pulled from Houston spec in Houston: Configuration.
Electrical Designer: Kenny Na (WARG EE F24 Co-op)
Requirements
Should be powered Powered by a 3S (12V) battery input.
In the context of integrating with the ELRS board, an XT60 connector should be provided, and additional PWM input from a header pin should be placed (unsure of this requirement).
3x solder pads for BLDC connection.
Supports DSHOT input.
More resistant to noise in transmission versus PWM, as DSHOT is a digital protocol.
Must use the AM32 open-source firmware for motor control. (https://am32.ca)
This uses a sinusoidal algorithm to control the BLDC. (no FOC)
Has a strict MCU compatibility list (we would preferably use a smaller ST chip)
Designed around an target motor (in Houston): https://innov8tivedesigns.com/cobra-cm-2217-20-brushless-motor-kv-950.html
Standard 3-phase brushless DC motor with 12 stator windings and 14 exterior magnet poles, meaning 4 coil windings per phase. Designed for 3S/4S power source.
With a higher density of magnet poles in the rotor, smoother torque is able to be produced by the motor. The rotor being on the outside gives more torque as well.
Maximum continuous current of 20 Amps.
Should be accounted for during FET selection.
Components
Microcontroller Selection
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Microcontroller | Option 1 | Option 2 | Option 3 |
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Name | STSPIN32F0 | STM32L431 | STM32F051 |
Price/unit | $4.34 | $5.20 | $5.59 |
Pros | Integrated MCU with STM32F031, DC-DC, LDO, and gate driver for BLDC applications. Price can’t really be compared to other options. Physical design would be very compact since gate driver is integrated. | Previous Used in previous ESC design from WARG, might be overkill | |
Cons |
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