Hello all! Sorry, my electronics skills are very limited so I need a help or directions to research.
I'm building a basic locomotive controller (for railway modelling) using an Arduino Uno card to control a L298N H bridge through PWM outputs. It works fine except for an annoying buzz sound on the dc motor due to the default Arduino's PWM frequency of 498Hz. So I changed the frequency to a value beyond the audible spectrum and set it to 20KHz. The annoying buzz sound was eliminated but the response of the dc motor is quite different. With the default frequency of 498Hz the locomotive starts to moving when I input a value of ~ 16, in a range of 0 to 255 to define the duty cycle variable. But at 20KHz, the locomotive only starts to moving with a value of ~ 128 and with 32KHz the value raises to ~200.
I would like to know if there is a way to have the same smooth response of the motor at those higher frequencies as when using 498Hz. Increasing frequencies, the controller range becomes narrower causing a more "nervous" reaction of the motor. Do I need another type of transistor that support high frequency switching? I am using a L298N H Bridge and have also used TIP120 with same results.
Thanks in advance for any direction.
chi.sp
(Brazil)
I'm building a basic locomotive controller (for railway modelling) using an Arduino Uno card to control a L298N H bridge through PWM outputs. It works fine except for an annoying buzz sound on the dc motor due to the default Arduino's PWM frequency of 498Hz. So I changed the frequency to a value beyond the audible spectrum and set it to 20KHz. The annoying buzz sound was eliminated but the response of the dc motor is quite different. With the default frequency of 498Hz the locomotive starts to moving when I input a value of ~ 16, in a range of 0 to 255 to define the duty cycle variable. But at 20KHz, the locomotive only starts to moving with a value of ~ 128 and with 32KHz the value raises to ~200.
I would like to know if there is a way to have the same smooth response of the motor at those higher frequencies as when using 498Hz. Increasing frequencies, the controller range becomes narrower causing a more "nervous" reaction of the motor. Do I need another type of transistor that support high frequency switching? I am using a L298N H Bridge and have also used TIP120 with same results.
Thanks in advance for any direction.
chi.sp
(Brazil)