Temperature Control using PID via Simulink

I found that after i insert PID parameters in the model, the lightbulb keep on flickering due to fluatuated duty cycle. Also, i found that no improvement is done using the PID parameters . Does this means PID dont have any function at all in improving the lightbulb performance? Theorectically, PID suppose is better than using ON/OFF and Deadband as it could reduce flickering. The results obtained is opposing the theory. Whats wrong with the model build as shown in Figure below?

Answer 1

[Ege Keskin]

You might achieve better results by directly using the PID block on simulink.