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3 Phase inverter explanation? Answered

I am trying to make sense of how to create a simple 3 phase inverter, but the design I have found requires the use of a PIC micro controller for pulsed width modulation to control the 3 half inverters in the image below. I do not have experience with this specific type of micro controller and am unable to find a simple explanation of how to set it up to do this, except how to connect it to the basic circuit at the transistor bases. Would anyone be able to explain to me how to wire/program/control frequency with the pic micro controller or an alternative method that would yield 3 phase power (0-120-240) because the manual and this page have be very very hard to understand to a beginner. I do not need any sort of feedback from the motor because the load will be constant and relatively small, and will most likely run it either at a constant or if easily doable linearly increasing frequency. Can someone PLEASE give me a good simple set of instructions on how to either replace this micro controller with something simpler or wire/program it to do this? Thanks!


What you want is very hard to do, and is beyond the skills of beginners. The Microchip paper is actually a model of clarity about the subject.

Rather than build a very sophisiticated piece of electronics, just buy yourself a single to three phase inverter !


They don't seem to come in the size or power necessary, I need something EXTREMELY compact... And most of the phase inverters I found are far larger than this task would find suitable... Any chance you could actually answer the actual question as opposed to explain why you shouldn't?

Its one of those questions that if you have to ask it, you wouldn't understand the answer. The Microchip paper is excellent, and is a complete how-to for those that understand it. Get 10 years of electronic design and practice under your belt, and you could do it too. Sometimes there aren't any shortcuts.

Like your linear motor question, you just have to learn some serious stuff.

I already found my answers to that. and what i'm asking isn't horribly complex: i need to create 3 120 degree out of phase currents by pulse width modulation. I do not need a perfect sine wave, I don't need anything especially fancy. the microchip paper explains probably perfectly fine in terms of things for that specific type of microchip. I would have no trouble creating a program to do the same exact thing if this were a computer, and I do see what i need to do, I simply have no experience using this type of microchip and really I don't wish to invest in a more expensive, more complex chip that I could easily program. The fact remains that this specific task does NOT require years and years of electronics design experience, I need not reinvent the wheel for it already exists. I need to implement it and I have enough of a grasp to understand how this works, I simple need to understand how to do this without investing into a far more expensive chip than is necessary for PWM in this case. Its not like this is a complex algorithm, but I'm not dealing in my comfort zone here of completely and easily programmable computers/micro-controllers, I am dealing with something significantly simpler and less obvious. For that matter, I don't even need a variable frequency drive, I could manage with one set frequency, I simple need to know how to put 3 of them 120 degrees out of phase with one another. Also, how is it that you respond ALL of my questions? How about instead of saying how not to do it, realize that I'm not asking you to teach me to design a circuit. Since you are already proficient in that, I come here asking for someone to help me do that instead of tell me that I can't. I KNOW I can't thats why I'm asking other people if they are willing to give me at least enough information to let me fill in the blanks on my own. I don't need to know how the microcontroller works to be able to use it in a fashion which it has been used for for years and years, I need only a set of instructions, which i ASSURE you i would be able to follow. Will you help me or simple keep on saying otherwise? And while I do need to learn some serious stuff, I wouldn't ask others for help unless I had serious trouble finding that information.