soft starter for three phase induction motor using ARDUINO - Page 1
Forum section: electronics / general

author: vis5254
author_rank: Contributor
timestamp: January 30, 2019, 02:47:15 pm
content: Greetings everyone , i got a project to implement a soft starter for 3 phase motor . realized it will be cheaper if i used a zero crossing detector to give input to ARDUINO and depending on it , ARDUINO controlled the TRIAC firing through opto isolators . i really find it difficult in Coding ARDUINO . so if someone has done this research , could plz provide necessary circuit and program code for this project .

author: krish2487
author_rank: Frequent Contributor
timestamp: January 30, 2019, 02:54:59 pm
content: Before anyone else pitches in with stronger words, I ll give a bit of advice.No one here is going to do your work for you.State your problem. Show what you have done, identify where you are having a problem. Further show what you done to identify and isolate the issue.State your hypothesis, backup with data.Then ask for help.People will gladly offer help or suggestions.Asking people to do your work for you in the guise of "help" will get you nothing. If it is a contract work, then you can make a post in the "jobs" section and hire a professional for his/her time.

author: rstofer
author_rank: Super Contributor
timestamp: January 30, 2019, 03:51:44 pm
content: You need to hit up Google.Microchip has a LOT of app notes on motor control:http://ww1.microchip.com/downloads/en/AppNotes/00001660B.pdfThe code is elsewhere - it will be for a PIC, not an Arduino so not worth findingI searched for 'Arduino 3 phase motor control soft start' and there are over 600,000 hits including:http://microcontrollerslab.com/soft-starter-for-3-phase-induction-motor-using-arduino/

author: Doctorandus_P
author_rank: Super Contributor
timestamp: January 30, 2019, 04:49:39 pm
content: I think it's best for people who are struggling with "arduino" to not be building soft starters (just yet).Anyway, commercial soft strarters cost around EUR 100 or so. What's there to gain?

author: rstofer
author_rank: Super Contributor
timestamp: January 30, 2019, 07:25:44 pm
content: From the links above, the uC will receive 2 interrupts per phase per cycle or about 360 interrupts per second (assuming 60 Hz). Then all that needs to happen is for a Triac to get fired at some time delay after zero crossing. Only 3 timers are necessary, one per phase, fired off at the two zero crossings per cycle. That's probably why the projects are using Mega boards, the standard Arduino ATmega328P has only two timers. The Mega has 5.I'm not sure how effective the Arduino libraries are going to be. I would be thinking in terms of writing the code to interact directly with the hardware.The interrupt routines need to be very short. Once zero crossing occurs, we need to get the timer started quickly. When the timer interrupt occurs, we need to fire the Triac quickly. There are a lot of things going on and a lot of interrupts firing.One idea that just flew past: Use 3 Arduinos, one per phase. It simplifies the code substantially as each uses the exact same code and simply interrupts on the appropriate zero crossing, starts a timer, gets an interrupt on timeout and fires the Triac.There are details omitted: How long should the timer delay be? It could be 0 ns if we want 100% voltage so we need to account for that. I suppose there needs to be an analog input to determine where some knob is set that controls speed. Just the interrupt prolog code are going to account for some additional delay.I haven't looked at any of the projects in detail. I would just buy a variable speed drive.Given the idea of 3 uCs, I might be inclined to use something much smaller than an Arduino but I would need to resolve device programming before I walked away from the Arduino. In any event, I wouldn't be using any of the Arduino supplied code. I would want my code very tight!

author: darshan
author_rank: Newbie
timestamp: December 26, 2020, 05:00:41 am
content: Vis5254Sir, I need your help especially project related Information!!Can you give me your mail id??My email id is : darshanpanchal2011@gmail.com

author: Siwastaja
author_rank: Super Contributor
timestamp: December 26, 2020, 03:48:09 pm
content: Get a VFD.

author: IconicPCB
author_rank: Super Contributor
timestamp: January 05, 2021, 06:26:19 am
content: Its a 3 phase induction motor... how do you propose to sense the rotor position? and how do you propose to energise it?Forget the fact that it is an arduino.... that is not where the problem is...DEFINE FUNDAMENTAL ISSUES FIRST

author: BravoV
author_rank: Super Contributor
timestamp: January 05, 2021, 07:33:30 am
content: Quote from: Siwastaja on December 26, 2020, 03:48:09 pmBe prepared to get the nag, on how to build the VFD using 741, prolly fake 2N3055 and few resistors and capacitors, and also the PCB layout too please ... Sir.

author: mikerj
author_rank: Super Contributor
timestamp: January 05, 2021, 08:19:23 am
content: Quote from: IconicPCB on January 05, 2021, 06:26:19 amWhy would you need to sense position? The three phase mains supply doesn't sense the position of a three phase motor...

author: IconicPCB
author_rank: Super Contributor
timestamp: January 05, 2021, 11:07:09 am
content: mikerj.....BZZZZZTTTTT the question aimrd at the OP . see zero crossing detector proposition.

author: Siwastaja
author_rank: Super Contributor
timestamp: January 05, 2021, 11:48:04 am
content: Quote from: IconicPCB on January 05, 2021, 11:07:09 amYour question makes zero sense, unless it's a trick question supposed to make no sense.Neither VFD nor zero crossing detection has nothing to do with rotor position sensing.Rotor speed (not position) sense could be applicable in a VFD, though (most often this is just estimated i.e. sensorless).

author: IconicPCB
author_rank: Super Contributor
timestamp: January 05, 2021, 08:43:33 pm
content: Siwastaja.Spot on.Read the very first post for an explanation of zero crossing issue.The comment was intended for the OP to perhaps elicit some critical thought.

author: themadhippy
author_rank: Super Contributor
timestamp: January 05, 2021, 09:23:51 pm
content: whats wrong with the old,tried and tested star delta starter?

author: mikerj
author_rank: Super Contributor
timestamp: January 06, 2021, 08:52:08 am
content: Quote from: IconicPCB on January 05, 2021, 08:43:33 pmHaving re-read the very first post, your question still makes zero sense. Perhaps you can help the OP, myself and others by explaining why zero crossing detection requires position sensing? What am I missing?

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: January 10, 2021, 06:52:25 pm
content: I would start by getting one phase working with the Arduino then convert the code to work with 3 using time division multiplexing of the software.I have done a bit of motor speed control and simply ramping up the phase angle worked very well.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: January 11, 2021, 02:47:50 am
content: Be careful how you sense zero crossing. Phase to neutral zero is 30 degrees away from phase to phase zero. You need to sense it the same way the motor windings are connected.