US 2014/0368181 A1Published application

Technique for enhancing the power output of an electrostatic generator employing parametric resonance

AssigneeLawrence Livermore National Security, LLC

InventorRichard F. Post

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Abstract

A circuit-based technique enhances the power output of electrostatic generators employing an array of axially oriented rods or tubes or azimuthal corrugated metal surfaces for their electrodes. During generator operation, the peak voltage across the electrodes occurs at an azimuthal position that is intermediate between the position of minimum gap and maximum gap. If this position is also close to the azimuthal angle where the rate of change of capacity is a maximum, then the highest rf power output possible for a given maximum allowable voltage at the minimum gap can be attained. This rf power output is then coupled to the generator load through a coupling condenser that prevents suppression of the dc charging potential by conduction through the load. Optimized circuit values produce phase shifts in the rf output voltage that allow higher power output to occur at the same voltage limit at the minimum gap position.

Claims36

Dependent claims

A method, comprising:

providing a circuit including:
a source of positive dc voltage connected to a first inductor which is connected to a first variable capacitor (VC) which is connected to a second VC which is connected to a second inductor which is connected to a source of negative dc voltage, wherein said first VC and said second VC are synchronously monotonically variable between a maximum gap and a minimum gap, wherein said first inductor in series with said first VC forms a first series-resonant circuit, wherein said second inductor in series with said second VC forms a second series-resonant circuit, wherein each of said first series-resonant circuit and said second series-resonant circuit are configured to comprise a resonant frequency that varies over a band of frequencies that includes the operating frequency of said first VC and said second VC;
a first coupling capacitor (CC) connected to a node between said first inductor and said first VC;
a second CC connected to a node between said second inductor and said second VC;
and
a load connected between said first CC and said second CC;
determining a target voltage at said minimum gap, wherein said target voltage is a specific voltage that is less than the breakdown voltage at said minimum gap;
and
simultaneously maintaining said target voltage at said minimum gap while synchronously adjusting the value of said first CC and said second CC to move the peak phase of the generated voltage to a new position to produce an increased allowable voltage due to an increased breakdown voltage at said new position relative to the allowable voltage at said new position prior to the step of adjusting the value of said first CC and said second CC.

6 more elements

A method, comprising:

providing a circuit including:
a first dc voltage source having its positive terminal connected to a first inductor which is connected to a first variable capacitor (VC) which is connected to a second VC which is connected to a second inductor which is connected to the negative terminal of a second dc voltage source, wherein said first VC and said second VC are synchronously monotonically variable between a maximum gap and a minimum gap, wherein said first inductor in series with said first VC forms a first series-resonant circuit, wherein said second inductor in series with said second VC forms a second series-resonant circuit, wherein each of said first series-resonant circuit and said second series-resonant circuit are configured to comprise a resonant frequency that varies over a band of frequencies that includes the operating frequency of said first VC and said second VC;
a first load connected to the negative terminal of said first dc voltage source, wherein the other terminal of said first load is connected to ground;
a first shunt inductor in parallel with said first load;
a second load connected to the positive terminal of said second dc voltage source, wherein the other terminal of said second load is further connected to ground;
a second shunt inductor in parallel with said second load;
determining a target voltage at said minimum gap, wherein said target voltage is a specific voltage that is less than the breakdown voltage at said minimum gap;
and
simultaneously maintaining said target voltage while synchronously adjusting the value of said first shunt inductor and said second shunt inductor to move the peak phase of the generated voltage to a new position to produce an increased allowable voltage due to an increased breakdown voltage at said new position relative to the allowable voltage at said new position prior to the step of adjusting the value of said first CC and said second CC.

6 more elements

An apparatus, comprising:

providing a circuit including:
a first dc voltage source having its positive terminal connected to a first inductor which is connected to a first variable capacitor (VC) which is connected to a second VC which is connected to a second inductor which is connected to the negative terminal of a second dc voltage source, wherein said first VC and said second VC are synchronously monotonically variable between a maximum gap and a minimum gap, wherein said first inductor in series with said first VC forms a first series-resonant circuit, wherein said second inductor in series with said second VC forms a second series-resonant circuit, wherein each of said first series-resonant circuit and said second series-resonant circuit are configured to comprise a resonant frequency that varies over a band of frequencies that includes the operating frequency of said first VC and said second VC;
a first load connected to the negative terminal of said first dc voltage source, wherein the other terminal of said first load is connected to ground;
a first shunt inductor in parallel with said first load;
a second load connected to the positive terminal of said second dc voltage source, wherein the other terminal of said second load is further connected to ground;
and
a second shunt inductor in parallel with said second load;
wherein the values of said first shunt inductor and said second shunt inductor are selected such that the peak phase of a voltage generated by said first VC and said second VC occurs at a larger gap position than at larger values of said first shunt inductor and said second shunt inductor.

5 more elements

Dependencies are inferred from the claim text.