Speed control of dc motor 220v

Thread Starter

Yacer

Joined May 11, 2020
4
Hello everyone,
I want to carry out a project in which i can control a DC motor (220 v) using pic 16f876a This project is based on the following steps below: First off, i started by applying the method of detecting zero crossing with my pic, employing a bridge rectifier, a zener diode as voltage regulator,optocoupler for the hardware portion of zero cross detection. The bridge rectifier rectifies this AC voltage to DC (knowing that the frequency is 50hz), but since there is no bulk smoothing capacitor, the output is not pure DC. The pic16F877a detects the zero crossing using the RB0/INT external interrupt function My pic16F876a is coded to enable the external interrupt. An interrupt is generated upon the falling edge of RB0. This what will make my pic16f876a generates the PWM signal Now i want to make this PWM signal variable using a variable delay (i don't want to use a timer, just a simple instructions to avoid abstraction, by implementing vdelay in my code) in order to control and vary continuously my DC motor speed (either to increase or decrease its speed) This requires the calculation of my rectified sinusoidal signal average value along the full period of the DC signal (here i want to calculate each time the average value in a small part of the full period) by implementing integral operation. I will use two pushbuttons connected to my pic16f876a for incrementing or decrementing the motor speed. So would you please help me find the right code using mikroc pro for pic ?
Sincerely,
 

MaxHeadRoom

Joined Jul 18, 2013
20,716
Why not copy the methods used in the Treadmill controllers, there is a version which used a SCR bridge for phase angle control or the later PWM versions, it is simpler if only one direction is required.
There is reverse engineered schematics for both here if you search. MC-60 and MC2100.
In the PWM version they use a SCR after the bridge, 100/120 cycle ripple, to control accel and decel.
For accurate control, you would need a feed back signal of some kind.
Max.
 

schmitt trigger

Joined Jul 12, 2010
243
What is your target?

- Is it to learn the hardware design an AC to DC motor controller, using a microcontroller and SCRs as the primary building blocks? And all of the ancillary circuit that goes with it?

- Or is it to practice writing the code, in a specific language, that will control it?
 

Thread Starter

Yacer

Joined May 11, 2020
4
What is your target?

- Is it to learn the hardware design an AC to DC motor controller, using a microcontroller and SCRs as the primary building blocks? And all of the ancillary circuit that goes with it?

- Or is it to practice writing the code, in a specific language, that will control it?
As you can see below i've just finished with the circuit, the main target right now is to write an appropriate code using "mikroC PRO for PIC" to control the DC motor (speed + rotation direction)
MOTOR CONTROL.JPG
 
Last edited:

Thread Starter

Yacer

Joined May 11, 2020
4
Why not copy the methods used in the Treadmill controllers, there is a version which used a SCR bridge for phase angle control or the later PWM versions, it is simpler if only one direction is required.
There is reverse engineered schematics for both here if you search. MC-60 and MC2100.
In the PWM version they use a SCR after the bridge, 100/120 cycle ripple, to control accel and decel.
For accurate control, you would need a feed back signal of some kind.
Max.
Thank you for suggesting me this alternative method, and it's really helpful, but in my project I'm supposed to drive my DC motor and control it using a microcontroller
 
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