Authors
Abstract
The purpose of this work is to study, analyze, and design a half-bridge seriesparallel
resonant inverter for induction heating applications. A pulse width modulation
(PWM)-based double integral sliding mode voltage controlled buck converter is
proposed for control the induction heating power. This type of controller is used in
order to obtain very small steady state error, stable and fast dynamic response, and
robustness against variations in the line voltage and converter parameters. A small
induction heating coil is designed and constructed. A carbon steel (C45) cylindrical
billet is used as a load. The induction heating load parameters (RL and LL) are
measured at the resonant frequency of 85 kHz. The parameters of the resonant circuit
are chosen for operation at resonant. The inverter is operated at unity power factor by
phased locked loop (PLL) control irrespective of load variations, with maximum
current gain, and practically no voltage spikes in the switching devices at turn-off,
therefore no snubber circuit is used for operation at unity power factor. A power
MOSFET transistor is used as a switching device for buck converter and the IGBT
transistor is used as a switching device for the inverter. A complete designed system is
simulated using Matlab/Simulink. All the electronic control circuits are designed and
implemented. The practical results are compared with simulation results to verify the
proposed induction heating system. A close agreement between simulation and
practical results is noticed and a good performance is achieved.
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