Self-generating inverters with semiconductive controlled rectifiers

Claim 1

A SELF-GENERATING INVERTER COMPRISING: AT LEAST ONE SEMICONDUCTOR CONTROLLED RECTIFIER HAVING MAIN CURRENT CIRCUIT ELECTRODES AND A CONTROL ELECTRODE, SAID MAIN CURRENT CIRCUIT ELECTRODES BEING ADAPTED FOR CONNECTION TO THE RESPECTIVE TERMINALS OF A SOURCE OF DIRECT CURRENT SUPPLY VOLTAGE, A FIRST RESONANT CIRCUIT HAVING SERIES RESONANCE PROPERTIES, ONE OF THE MAIN CURRENT CIRCUIT ELECTRODES OF THE CONTROLLED RECTIFIER BEING CONNECTED TO A CORRESPONDING TERMINAL OF THE SUPPLY SOURCE THROUGH SAID FIRST RESONANT CIRCUIT, MEANS COUPLING THE CAPACITIVE PORTION OF SAID FIRST RESONANT CIRCUIT WITH A LOAD CIRCUIT, A SECOND RESONANT CIRCUIT CONNECTED ACROSS SAID CAPACITIVE PORTION OF SAID FIRST RESONANT CIRCUIT, SAID SECOND RESONANT CIRCUIT INCLUDING A PARALLEL RESONANT CIRCUIT COMPRISING A FIRST CAPACITOR AND A FIRST INDUCTOR, A THIRD REACTIVE ELEMENT CONNECTED IN SERIES WITH THE PARALLEL RESONANT CIRCUIT, AT LEAST ONE DAMPING RESISTOR UNDERCRITICALLY DAMPING SAID SECOND RESONANT CIRCUIT, AND THE PRIMARY WINDING OF A CONTROL TRANSFORMER, SAID CONTROL TRANSFORMER HAVING A SATURABLE CORE OF FERROMAGNETIC MATERIAL ON WHICH SAID PRIMARY WINDING AND AT LEAST ONE SECONDARY WINDING ARE WOUND, SAID PRIMARY WINDING BEING CONNECTED IN SERIES WITH ONE OF THE REACTIVE ELEMENTS IN SAID PARALLEL RESONANT CIRCUIT, SAID SECONDARY WINDING BEING COUPLED TO THE CIRCUIT BETWEEN THE CATHODE AND THE CONTROL ELECTRODE OF THE CONTROLLED RECTIFIER, SAID SATURABLE CORE CHANGING OVER FROM ONE SATURATION STATE TO THE OPPOSITE SATURATION STATE IN RESPONSE TO THE PASSAGE THROUGH ZERO OF THE CURRENT THROUGH SAID PRIMARY WI NDING AND PRODUCING A PULSE THROUGH SAID SECONDARY WINDING FOR APPLICATION TO SAID CONTROL ELECTRODE, THE SWITCHING FREQUENCY OF THE INVERTER BEING SUBSTANTIALLY DETERMINED BY SAID REACTIVE AND RESISTIVE ELEMENTS OF SAID SECOND RESONANT CIRCUIT, SAID DAMPING RESISTOR HAVING A RESISTANCE WHICH VARIES SHARPLY WITH ITS TEMPERATURE AND ACTING TO SHARPLY INCREASE THE DAMPING OF SAID SECOND RESONANT CIRCUIT AND TO INCREASE THE OPERATING FREQUENCY OF THE INVERTER IN RESPONSE TO A CHANGE IN ITS TEMPERATURE.