back to pid

seems like I am going around in circles. As I cannot get a good result with hysteresis, I will try again with PID. Here is the image with kp = 0.1 and ki = 1. Current is averaged over 20 samples at a sample time of 1e-5. Main sample time is 4e-5 to correspond with a PWM period of 3000.



this is much weaker than when originally tuning the PID controller. I should be able to repeat the old result by reducing the averaging to 1.

DISREGARD THE PREVIOUS IMAGE. I HAD IT CONNECTED IN A THREE WIRE CONFIG RATHER THAN A 6 WIRE CONFIG.

here is the image with no averaging:



and with averaging of 20.



with a load on:




I THINK THAT I SHOULD BE USING A LOAD FOR ALL MY MEASUREMENTS.

try to remove the ki and use kp = 0.1

dnw

kp = 1

dnw

kp = 10



kp = 5




kp = 3

kp = 1.5

dnw

guess that kp is around add ki = 1



with kp = 1 and ki = 1:



this is really ugly and draws lots of current.

kp = 0.1 and ki = 1 seems pretty good still - work towards that

kp = .5 ki = 1



maybe it is oscillating due to the ki - try:
kp = 0.5 ki = .5



getting worse keep ki at 1 and lower kp to 0.25



a bit better but now I remember that kp = 0.1 and ki = 1 was oscillatory so I should be going for less than that

try kp = 0.1 and ki = 0.5



looks okay try to add kd = 1



does not look much different - try kd = 10



does not look much better and has induced some noise... remove Kd

maybe try to reduce the average width to 10



looks a bit better - try to go to average width of 4 (equate with one pwm width)




looks worse - 10 looks like a good number but I would really like to have it over an integer number of PWM cycles - try 8



okay - try 12



okay but still oscillatory - need to reduce ki and kp

try kp = 0.05 ki = 0.5



a bit slow - try kp = 0.1, ki = 0.3



still a bit slow - 0.1 and 0.5 seems to be the best that I can do for the moment

I may need to add som integral saturatino control

try kic = 1



gone more oscillatory try kic = 0.5