Best method of controlling a resistive heater

Hey all, 

I'm creating a resistive heating system (I don't have a choice on that, the resistors are already provided), and I'm looking for the best method of being able to control this. 

Resistors are 50W 4 Ohm Panel Mount Units, of which I've got about 32, but I'll likely need more going forward. 

Currently it uses 4 zones, each of which use a custom MOSFET PCB which is PWM pulsed by an Arduino which is all fed from 4 24V DC power supplies. 

This has worked OK thus far, but it's not the most reliable and I was wondering if there's something COTS which would suit this better that provides a better method of control to be able to vary the temperature of the panel, as the current ones have no sense feedback, so they're unable to temperature compensate. 

I was wondering if an inverter could sort something like this? 

I know I'm limited by the supply of the room (which is just 230V, there's no 415V supply etc.), but I'm curious to see what people recommend in terms of whether to look at motor controllers as off the shelf PWM units, current stabilised sources etc. 

Parents
  • So what I'm thinking is this. 

    Taking a single panel, I have 16 places for resistors. 

    If I wire up a string of 8 in series I have 32 Ohm series resistance, which on a 230V supply equates into 7.2A approx (1.66kW).

    This allows me to wire up an entire string of 8 and have a backup string if it fails during an operation. 

    I could then run this on a 20-30A solid state relay and control this with the digital pins of an arduino, giving precise on off control, I'd just then need to integrate some temperature sensors to give it a PID loop. 

    How's that sound?

    My next question is going to be how much can I put on a single ring before it blows! as the 4 panels would draw 28.8A ( 6.6kW)

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  • So what I'm thinking is this. 

    Taking a single panel, I have 16 places for resistors. 

    If I wire up a string of 8 in series I have 32 Ohm series resistance, which on a 230V supply equates into 7.2A approx (1.66kW).

    This allows me to wire up an entire string of 8 and have a backup string if it fails during an operation. 

    I could then run this on a 20-30A solid state relay and control this with the digital pins of an arduino, giving precise on off control, I'd just then need to integrate some temperature sensors to give it a PID loop. 

    How's that sound?

    My next question is going to be how much can I put on a single ring before it blows! as the 4 panels would draw 28.8A ( 6.6kW)

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