Resonant power supply for use with high inductive loads and method of providing same

摘要

A resonant power supply (900) for use with high inductive loads includes an input rectifier (903) and a switching inverter formed using a plurality of parallel connected half bridge networks for switching the voltage provided from the input rectifier (903). A transformer (927) is used whose primary is connected to the switching inverter and whose secondary is connected to load such as a crucible (931). A capacitor (929) is used in series with the primary of the transformer (927) for resonating the inductance in the secondary circuit at the frequency of the switching inverter to provide maximum power transfer to the crucible (931).

主权项

1. A switching power supply for heating a graphite crucible in an electrode furnace for providing maximum power to a transformer coupled load containing high inductive reactance comprising:
a supply of AC voltage; a rectifier circuit converting said AC voltage to a DC voltage; an inverter having an input coupled to said rectifier to receive said DC voltage, said inverter switching said DC voltage at a switching frequency of from 25 kHz to 1 MHz, said inverter having an output; at least one transformer having a primary winding and a secondary winding; a secondary circuit directly connected to said secondary winding, said secondary circuit including an electrode connected to a graphite crucible; and wherein said primary winding is coupled to said output of said inverter by a capacitor coupled in series with said primary winding and the capacitance of said capacitor and switching frequency is selected for providing operating power to said secondary circuit at a resonant frequency of said secondary circuit.