Extinction of plasma arcs

Abstract

A circuit configuration reduces electrical energy stored in a lead inductance formed by a plurality of leads that connect a power supply unit with a load. The circuit configuration includes a switching device in operative connection with at least one of the leads for enabling or interrupting power to the load. The circuit configuration also includes a first electrical nonlinear device arranged in parallel with the switching device; an energy storing device arranged in parallel with the switching device and in series with the first electrical nonlinear device; and a pre-charging circuit in operative connection with the energy storing device for charging the energy storing device to a pre-determined voltage level while power to the load is enabled.

1 . A circuit configuration for reducing electrical energy stored in a lead inductance that is formed by a plurality of leads for connecting a power supply unit with a load, the circuit configuration comprising:
 a switching device in operative connection with at least one of the leads and configured to enable power to be supplied to the load;   a first electrical nonlinear device in parallel with the switching device;   an energy storing device in parallel with the switching device and in series with the first electrical nonlinear device; and   a pre-charging circuit in operative connection with the energy storing device and being configured to store energy in the energy storing device to a pre-determined energy level while power supply to the load is enabled by the switching device.   
     
     
         2 . The circuit configuration of  claim 1 , wherein the first electrical nonlinear device includes a valve device. 
     
     
         3 . The circuit configuration of  claim 2 , wherein the valve device is a diode. 
     
     
         4 . The circuit configuration of  claim 1 , wherein the energy storing device is a capacitive device. 
     
     
         5 . The circuit configuration of  claim 1 , wherein the first electrical nonlinear device is configured to block a pre-charging current from the pre-charging circuit for storing energy in the energy storing device. 
     
     
         6 . The circuit configuration of  claim 1 , wherein the pre-charging circuit is a voltage-controlled externally powered unit. 
     
     
         7 . The circuit configuration of  claim 1 , wherein the pre-charging circuit comprises a second electrical nonlinear device connected between one of the leads and a node located between the energy storing device and the first electrical nonlinear device. 
     
     
         8 . The circuit configuration of  claim 7 , wherein one or more of the first electrical nonlinear device and the second electrical nonlinear device is a diode or a controlled MOSFET. 
     
     
         9 . The circuit configuration of  claim 7 , wherein the first and second electrical nonlinear devices are arranged with opposite blocking directions. 
     
     
         10 . The circuit configuration of  claim 1 , further comprising a discharging circuit in operative connection with the energy storing device to discharge electrical energy stored within the energy storing device. 
     
     
         11 . The circuit arrangement of  claim 10 , wherein the discharging circuit is integrated with the pre-charging circuit. 
     
     
         12 . The circuit arrangement of  claim 10 , wherein the discharging circuit comprises:
 a resistive element connected in parallel with the second electrical nonlinear device; and   a discharge switching device connected to the energy storing device for discharging the energy storing device through the resistive element.   
     
     
         13 . The circuit configuration of  claim 1 , wherein the plurality of leads connects the power supply unit with a plasma application. 
     
     
         14 . The circuit configuration of  claim 1 , further comprising a power supply unit that supplies power to the load. 
     
     
         15 . A power supply apparatus for plasma applications, the power supply apparatus comprising:
 a power supply unit; and   outputs for supplying power from the power supply unit to a plasma application through a plurality of leads;   wherein the power supply apparatus comprises a first circuit configuration for reducing electrical energy stored in a lead inductance that is formed by the plurality of leads, the circuit configuration comprising: a switching device in operative connection with at least one of the leads and configured to enabling power to be supplied to the load; a first electrical nonlinear device in parallel with the switching device; an energy storing device in parallel with the switching device and in series with the first electrical nonlinear device; and a pre-charging circuit in operative connection with the energy storing device and being configured to store energy in the energy storing device to a pre-determined energy level while power supply to the load is enabled by the switching device.   
     
     
         16 . The power supply apparatus of  claim 15 , further comprising a control unit that monitors an operational state of the plasma application, and controls at least the switching device in response to a result of the monitoring. 
     
     
         17 . The power supply apparatus of  claim 15 , wherein the power supply unit is a direct current power supply unit. 
     
     
         18 . The power supply apparatus of  claim 15 , wherein the power supply unit is an alternating current power supply unit. 
     
     
         19 . A method of reducing electrical energy stored in a lead inductance formed by a plurality of leads that connect a power supply unit with a load, the method comprising:
 interrupting power to the load with a switching device that is in operative connection with at least one of the leads;   prior to interrupting the power, pre-charging an energy storing device arranged in parallel with the switching device to a pre-determined energy level while the switching device is closed;   opening the switching device; and   discharging electrical energy stored in the energy storing device prior to closing the switching device.   
     
     
         20 . A method for arc extinction in plasma applications supplied by a direct-current power supply unit, the method comprising:
 monitoring an operational state of the plasma application with respect to an occurrence of plasma arcs;   interrupting power supply to the plasma application in response to a result of the monitoring by interrupting power to the plasma application by opening a switching device that, when closed, connects the direct-current power supply unit with the plasma application;   pre-charging an energy storing device arranged in parallel with the switching device to a pre-determined energy level while the switching device is closed; and   discharging electrical energy stored in the energy storing device prior to closing the switching device after power to the load has been interrupted by opening the switching device.   
     
     
         21 . The method of  claim 20 , further comprising applying an adjustable blocking time after interrupting power to the plasma application, during which a further interruption of power supply to the plasma application is inhibited.