Dear Friends,

I am from a Charitable NGO feeding mid-day meals to school going children across India. We are working on a temperature controlled Induction heating cookwares like Cook top, boilers, Wok, brat pans etc., Basically on the concepts of Multi-zone induction wok — IGBT zone switching, PID temperature control, and zone-level wall temperature sensing. I have specific requirements like the below

• Mutual coupling between concentric coil zones — has anyone implemented DSP-based cross-talk cancellation on a dome coil?
• IR thermopile at 3–8mm range looking upward at a SS vessel base — emissivity calibration approach?
• PID tuning for a large thermal mass vessel — any practical experience with anti-windup strategies for induction heating?

Attaching few files for your reference. Kindly suggest some practical design implementations and any leads who can render technical support at India

Mod: created new thread, Link to old thread
https://forum.allaboutcircuits.com/...n-coil-with-pid-controller.122175/post-979439

 

PID tuning for a large thermal mass vessel — any practical experience with anti-windup strategies for induction heating?

Have you considered Fuzzy Logic control, which does not have a integrator that is subject to windup.
Fuzzy Logic also can generally handle non-linear and hysteresis system characteristics better than PID which your system is likely to have, as PID is predicated on the system having a linear response.
Here's a tutorial on Fuzzy Logic, if interested.

 

How precisely does the temperature actually need to be controlled?? I have been very successful holding an oil tank temperature within +-2 degrees for many hours. Since the oil was circulating thru tested items the heating method was forcing it thru an orifice, with a bypass valve for whan it was not heating. The temperature control logic was ON/OFF with a 5 second interval and one degree of hysteresis. So control was either on or off at five second intervals. It was a commercially available controller, standard product. We did use a solid state control relay and the triac on/off connection to the controller. The only analog part of the system was the thermocouple.

 

This system is very much different from the oil tank system. I undrstand about induction heating, but we have no information at all as to what " temperature controlled Induction heating cookwares like Cook top, boilers, Wok, brat pans etc. " actually means. So here is a very specific question: Is the heat produced and applied in an ON/OFF manner??
OR, is the heat applied in a variable manner?? THAT is very important to know!!

PWM on/off heating on a cycle time of a few seconds would be a fairly linear variable.
Is the temperature to be controlled by measurement and feedback, or by setting the rate of heat application?? BOTH are used in everyday cooking by most people.
Probably only ON/OFF duty cycle is available. Linear control gets complex very quickly.
Really, is the temperature to be sensed at all?? THAT is a vital consideration. OR is it cooks judgement???