Arduino pwm buck converter12/11/2023 ![]() ![]() I believe that an Uno won't lend itself well to generating the PWM pulses you want. Maybe the manufacturer will sample a couple to you. I didn't readily find any for sale in singles. Here's an 8-phase PWM controller, made for applications like this. With just a couple of analogRead()'s, it gets off pretty far. If the next version of the IDE adds code between setting Timer2 and calling setup(), or if you add code at the beginning of setup(), the phase relationship will be less accurate. They're almost 180 degrees out pf phase, but that's largely a matter of luck. On the next tick, Timer2 starts counting down, while Timer1 counts up. Timer1 is set to one tick away from zero, upcounting, at a time when Timer2 is at zero, upcounting. That more or less works, because the phase-correct mode counts up to the top, and then down to the bottom, rather than rolling over. The code sets it explicitly to 0x7FFF, but Timer1 ignores the most significant byte in mode 1, and sets itself to 0xFF. Timer1 is set to full scale for its mode - 8-bit phase-correct PWM, mode 1 - rather than half-scale, as claimed in the text accompanying this code.Timer2 runs at 1/64 of the system clock, so it's still at zero when setup() executes. The last thing that the internal startup code does is to set up and start Timer2.It doesn't do anything intentional to establish any particular phase relationship between Timer1 and Timer2 it just gets lucky. I found an elegant solution for 2 phases here. If you do manage to design such a device then I think you will be able to walk into any power supply design job on the planet.Ī bit of advice I would give, is to try and design a 20A system to start with just to see how it goes. I am not sure I follow that line of thinking, a watt is a watt no matter how it is derived. I would love to use higher voltage, but the heater goes to 1500 deg Celsius and it would burn if I make it thinner. The other thing is that the current carrying capacity of coils will be limited by the magnetic saturation of the core. Your biggest problem will be getting any design stable and will require a specialist PCB layout, it is not a thing you can prototype on strip board. It has taken three or four CAD iterations to get the finished design. I have managed several professional power supply specialists and I have seen them struggle to get a stable step down switching regulator at 5 Amps. I don't doubt your willingness to learn but power supply design is a specialist subject. I have a Cherokee CAR2512FP, 2500W, it has >90% efficiency. Output required 1.5V at 1000A = output power of 1.5KW.ĭoes it not strike you that any of these figures are a bit unrealistic?Ĭome on, you can get an IBM BladeCenter power supply for 30$ on eBay(12V, 2000W). This is a very specialized application, I have to go with high current.Īssume 100% efficiency, 12V in 1.5V out gives a step down of 8 times so assume you have a current step up of the same. I do not need to resort to passive cooling options listed in data sheet.Īnd your thermal time constant for this is? Most people use PWM and a much higher voltage. Water cooled copper block would do it for sure, with minimal temperature difference. Next I need to dissipate 8W from 0.4 cm2 case surface. Junction to case temperature difference would be 8W1.8deg/W= 14 deg. I guess I need to dissipate less than 8W per MOSFET: I2R=125A^2 0.0005 Ohm=8W. Read the data sheet again especially the bit about thermal resistance. I have time at hands and I am willing to learn. I don't intend to sound disrespectful to professionals, but I will try to accomplish this project and gain some experience in the process. I am not sure about your level of expertise with electronics but this is a major, major undertaking and requires a high level of skill. I am particularly interested in Arduino Due because of higher clock frequency translating into higher PWM frequency at 10-12 bit resolution. ![]() What would be the maximum number of phases with this approach? It has to do with offsetting the timer counter register. I would like to avoid any interrupts in PWM outputs. Is it possible to get 8 phase shifted PWM signals to feed the buck converter drivers? PWM frequency would be constant, variable duty cycle. ![]() I would need 8 pairs of MOSFETs to handle the current, so it's better to have 2Pi/8 shift between 8 individual buck converters to minimize output oscillations. I would like to build a high current (~1000A) buck converter with very precise control (~0.1%) of output voltage. Hi, I am new to microcontrollers, please advise me if the following project is possible with Arduino. ![]()
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