AC SPEED CONTROL CODE

Finally I decided to use and understand a PID control method. Sometimes motor ran till its maximum RPM for unknown reason. Sometimes it jumped during start, sometimes during run. I tried a lot of motor control and phase cut synchronization algorithms but most of them had own disadvantages. NXP and Microchip has lot of useful information about controlling motors. I provided some links with dimming and motor control theory above (the first and the second link). I won't give a theory how AC phase cut works because there is nothing new. Some useful information about PID library usage.

AC SPEED CONTROL CODE

Took some pieces of PID usage code from here.RPM counting code took from here (Russian).Dimming code I used from here (IMHO the best dimmer).Got some ideas and took some pieces of code from here (Russian).Some theory, useful code and schematic is here.Also I used a tacho sensing circuit part from here. Max RPM is 1450! After my used pulleys will be around 480 RPM only!ДЄfter surfing the internet I found several speed controller projects and decided to make my own controller using found ideas.(could be increased by changing the triac) At Chinese stories I found a cheap AC motor speed controller with RPM stabilization feature. But I didn't had this chip and to see the RPM I had to make a tachometer. There is well known chip TDA1085 which is specially designed to control motors with speed sensors speed. Fortunately this kind of motors has tacho sensors and we can do a closed loop system to have a stable RPM even at load and control the torque. To control the motor peed we could use a SCR voltage regulator, but at low RPM the motor will be weak with no torque. Without it the motor will spin at it's maximum 15000-19000 RPM. Only one thing left - the motor speed controller. Otherwise it goes hot.ДЄs you could notice the guy from video used the motor which was salvaged from old washing machine. Limited working time - 10 minutes run / 6 minutes idle.Have to use set of pulleys or expensive electronic controller. Main disadvantages of this kind of motor: At first I used the asynchronous one phase motor with running capacitor. There is the video where you can watch the controller at work: Overspeed (usually when triac is damaged) protection.Motor stuck (or speed sensor malfunction) protection.Speed and torque control by PID algorithm.2x16 LCD display for status and RPM display.Push button of encoder starts and stops the motor.Rotary encoder lets to set desired RPM before motor start.Two speed ranges for quicker desired RPM change.It's an Arduino-controlled motor speed regulator which uses phase cut dimming method and PID algorithm. If you have no clue or if you are doubting about what you do, chances are you are going to be DEAD!!! DO NOT TOUCH WHEN IT IS CONNECTED TO THE GRID!!! WAIT!!! Let me just add a stronger warning here: This circuit is safe if it is built and implemented only by people who know what they are doing. The cooling plate of the Triac is attached to the mains. Unplug it before coming even close to the PCB. Do not build this if you are not confident about what you are doing. STOP!!! This circuit is attached to a 110-220 voltage. The PWM signal will decide the amount of voltage output to the AC motor that controls the speed of it.WARNING!!! At first, I'll write a quotation : The Arduino will take the input from the potentiometer and generates a PWM signal which is fed into the TRIAC and optocoupler circuit that will result in operating the AC fan at the desired speed. The speed of the fan is adjusted or varied through a 10K potentiometer. Then we have to control the time period for which the power will on and off. Using this pulse the zero-crossing point is detected by the Arduino. This optocoupler has a built-in LED and an output transistor that de-actives when the AC wave goes close to the zero-crossing point and they both are activated when the signal increases to the peak point. A 220V mains voltage is stepped down to 9V using a step-down transformer and then it is sent to a 4N25 Optocoupler. The first step in the working of this circuit is to detect the zero-crossing point, it is the point on the voltage curve where the voltage changes the direction.

Ac speed control