Control system design and small-signal analysis of a phase-shift-controlled series-resonant inverter for induction heating

A phase-shift-controlled series-resonant inverter operating at zero-voltage-switching (ZVS) is used as the power supply for an induction heating system. This system has two control loops: the phase-shift control loop regulates the output power; and the frequency control loop ensures ZVS for all load conditions. The design and implementation of these control loops are explained. The complete closed-loop small-signal model is obtained using the extended describing function method. The model predictions are compared with experimental data measured from a lab prototype.<
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