Am working on controlling an induction motor with a modified 8301 high current kit and having a question regarding the Rs calculations.
The software is based on the proj_lab04 project.
The controller is a piccolo 28069F.
The calculated Rs values are on the range of 1.0e-11 to 1.0e -4.
In the coarse Rs estimation, the value gMotorVars.Rs_ohm is calculated as 0.0175. This seems to be in reasonable range for the configuration in user.h.
When the fine Rs estimation starts, the value decreases to a value in the range above during the period of the fine estimation.
I experimented with longer and shorter times for the coarse and fine estimation. It appeared that the longer that the fine estimation runs (for example 10 - 20 seconds), the smaller the calculated value.
I varied the USER_MOTOR_RES_EST_CURRENT value from 5 - 15 amps with similar results. The current values measured on the scope were correct.
What parameters are used in the coarse versus the fine calculations?
And what might account for the difference in the coarse and fine calculations.
Other notes on testing and configuration:
- The current and voltage supplied to the motor were almost identical during the coarse and fine calculations. This was observed in adc values as well as with a scope/current meter and volt meter.
In user.h:
#define USER_IQ_FULL_SCALE_FREQ_Hz (400.0)
#define USER_IQ_FULL_SCALE_VOLTAGE_V (70)
#define USER_ADC_FULL_SCALE_VOLTAGE_V (120)
#define USER_IQ_FULL_SCALE_CURRENT_A (80)
#define USER_ADC_FULL_SCALE_CURRENT_A (165)
#define USER_MOTOR_MAGNETIZING_CURRENT (10.0)
#define USER_MOTOR_RES_EST_CURRENT (15.0)
Thanks in advance for help on this topic.
Allan