[IEEE APEC \'99. Fourteenth Annual Applied Power Electronics Conference and Exposition. 1999 Conference Proceedings (Cat. No.99CH36285) - Dallas, TX, USA (1999.03.18-1999.03.18)] APEC \'99. Fourteenth Annual Applied Power Electronics Conference and Exposition. 1999 Conference Proceedings (Cat. No.99CH36285) - Half-bridge series resonant inverter for induction heating applications with load-adaptive PFM control strategy