Feedbacks
Feedback loops, or simply feedbacks, are sensor lines that return the value of a certain magnitude to the control unit, with the purpose of using this information to optimize the control system parameters. From a functional point of view, there are two main types of feedbacks:
- Commutation feedback: This feedback returns sensor information relative to phase switching. Usually this is only used for motors that need electrical commutation (BLDC, BLAC...).
- Position/Velocity/Torque feedback: These feedbacks return sensor information about control magnitudes, and as such are usually used to close control loops.
The architecture of EMCL allows to use any feedback for this functionalities, and even some of them at the same time (for instance, using a quadrature incremental encoder for position feedback, and digital halls for commutation).
All feedback sensor lines have different resolution. Nevertheless, in order to simplify the understanding of this section, all resolution values are expressed in increments, as shown below:
Quadrature digital encoder: The number of increments per revolution directly depends on the sensor resolution.
EMCL-based controllers use x4 decoding when coupled with incremental encoders. Therefore, each transition in any of the two main encoder signals (A, B) will be considered to be an increment. As an example, if a 500CPR (cycles per revolution) encoder is used, the encoder resolution will be 2000 increments per mechanical revolution.
- Digital halls: There are 6 increments per electrical revolution or 6 increments per mechanical revolution * pair poles.
- Analog halls: There are 4096 increments per electrical revolution or 4096 increments per mechanical revolution * pair poles.
- Analog input: There are 4096 increments per mechanical revolution.
- PWM input: There are 65536 increments per mechanical revolution.
- SinCos (analog) encoder: The number of increments per revolution depends on the sensor resolution and the SinCos multiplier factor.
- Resolver input: There are 4096 increments per mechanical revolution.
- SSI encoder: The number of increments per mechanical revolutions depends on the number of bits assigned in the single-turn value of the SSI frame.
Each feedback has some number of objects associated that allow the configuration of its related parameters.