This document describes the process of upgrading the control of an existing induction heating system. The design and implementation of a new PCB for the control of the high frequency inverter is presented.
To design the new PCB, the specifications of the existing PCB were first analysed. Since we also wanted to upgrade the existing control, we made a PCB capable of measuring the phase lag between the voltage and current of the inverter, with a maximum error of ± 5°. By meeting this requirement, we solve the fundamental problem of the existing control, which is the inability to detect the peak of the resonance curve of the load of the induction heating device. Further, a schematic of the microcontroller program that calculates the phase and generates the control signals for the inverter is presented.
In the final part, the successful results of a practical test of the PCB implementation are presented. In addition to the frequency control (FC) strategy [1], the possibility of using the phase shifted pulse-width modulation (PS-PWM) control method [1] is shown.
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