Electrostatic machine system and method of operation

1. An electrostatic machine comprising:

a drive electrode and a stator electrode separated by a gap and forming a capacitor, wherein the drive electrode is configured to move with respect to the stator electrode;

a housing configured to enclose the drive electrode and the stator electrode, wherein the stator electrode is fixed to the housing; and

a dielectric fluid that fills a void defined by the housing, the drive electrode, and the stator electrode, wherein the dielectric fluid comprises a ketone, an oxalate, or a malonate, wherein

the ketone is of formula R 1 —C(O)—R 2 , wherein

R 1 is a substituted or unsubstituted C 2 -C 30 alkyl, aryl, aralkyl, or C 2 -C 30 alkenyl group and R 2 is a substituted or unsubstituted C 1 -C 30 alkyl, aryl, aralkyl, or C 2 -C 30 alkenyl group;

the oxalate is of formula

wherein:

R 1 is a substituted or unsubstituted C 5 -C 30 alkyl, aryl, aralkyl, or C 2 -C 30 alkenyl group and R 2 is a substituted or unsubstituted C 1 -C 30 alkyl, aryl, aralkyl, or C 2 -C 30 alkenyl group; and

the malonate is a compound of formula R 1 OC(O)C(R 6 )(R 7 )C(O)OR 2 , wherein:

R 6 and R 7 are individually H or alkyl, wherein at least one of R 6 or R 7 is alkyl, and

R 1 and R 2 are individually a substituted or unsubstituted C 1 -C 30 alkyl, aryl, aralkyl, or C 2 -C 30 alkenyl group.

2. The electrostatic machine of claim 1 , wherein the malonate is a compound of formula R 1 OC(O)C(R 6 )(R 7 )C(O)OR 2 , wherein at least one of R 6 or R 7 is alkyl, and R 1 and R 2 are individually a substituted or unsubstituted C 1 -C 30 alkyl or C 2 -C 30 alkenyl group.

3. The electrostatic machine of claim 1 , wherein the malonate is a compound of formula R 1 OC(O)C(R 6 )(R 7 )C(O)OR 2 , wherein at least one of R 6 or R 7 is alkyl, and R 1 and R 2 are individually a substituted or unsubstituted C 1 -C 24 alkyl or C 2 -C 24 alkenyl group.

4. The electrostatic machine of claim 1 , wherein the malonate is a compound of formula R 1 OC(O)C(R 6 )(R 7 )C(O)OR 2 , wherein at least one of R 6 or R 7 is alkyl, and R 1 and R 2 are individually a substituted or unsubstituted C 1 -C 12 alkyl or C 2 -C 12 alkenyl group.

5. The electrostatic machine of claim 1 , wherein R 1 is a substituted or unsubstituted C 5 -C 10 alkyl group or a substituted or unsubstituted C 5 -C 12 alkenyl group; and R 2 is a substituted or unsubstituted C 1 -C 3 alkyl group.

6. The electrostatic machine of claim 1 , wherein R 1 is a substituted or unsubstituted C 6 -C 18 aralkyl group; and R 2 is a substituted or unsubstituted C 1 -C 12 alkyl group.

7. The electrostatic machine of claim 1 , wherein the ketone is of the formula:

wherein:

R 3 is a substituted or unsubstituted C 1 -C 30 alkyl or a substituted or unsubstituted C 2 -C 30 alkenyl group;

R 4 is a substituted or unsubstituted C 1 -C 30 alkyl or a substituted or unsubstituted C 2 -C 30 alkenyl group; and

R 5 is a substituted or unsubstituted C 1 -C 30 alkyl or a substituted or unsubstituted C 2 -C 30 alkenyl group.

8. The electrostatic machine of claim 7 , wherein R 3 is a C 1 -C 10 alkyl or a substituted or unsubstituted C 2 -C 8 alkenyl group.

9. The electrostatic machine of claim 7 , wherein R 4 is a C 1 -C 3 alkyl group; and R 5 is a substituted or unsubstituted C 1 -C 10 alkyl group.

10. The electrostatic machine of claim 1 , wherein the ketone is 4,5-dimethylheptan-2-one, 2,8-dimethylnonan-5-one, or a mixture thereof.

11. The electrostatic machine of claim 1 comprising the oxalate, wherein

the oxalate comprises

diphenyl oxalate and derivatives thereof,

or a mixture of any two or more thereof.

12. The electrostatic machine of claim 1 comprising the malonate which is selected from the group consisting of diethyl methyl malonate, diethyl ethyl malonate, dibutyl methyl malonate, dibutyl ethyl malonate, and derivatives thereof, or a mixture of any two or more thereof.

13. The electrostatic machine of claim 1 , further comprising a current sourced inverter configured to convert direct current power into alternating current power via a plurality of switches, wherein the current sourced inverter is configured to provide the alternating current power across the drive electrode and the stator electrode, and wherein no passive electrical components are electrically connected between the drive electrode, the stator electrode, and the plurality of switches.

14. The electrostatic machine of claim 1 , further comprising a voltage sourced inverter configured to convert direct current power into alternating current power via a plurality of switches, wherein a plurality of inductors is electrically connected between the drive electrode, the stator electrode, and the plurality of switches.

15. The electrostatic machine of claim 1 , wherein the drive electrode comprises a drive plate, and wherein the stator electrode comprises a stator plate, and wherein the drive plate and the stator plate are parallel.

16. The electrostatic machine of claim 15 , wherein the drive plate comprises a plurality of teeth around a periphery of the drive plate, wherein the stator plate comprises an annulus with a plurality of teeth extending from an inside circumference of the annulus, and wherein the teeth of the drive plate and the teeth of the stator plate form the capacitor.

17. The electrostatic machine of claim 1 , wherein the housing comprises at least one of polypropylene, acetal, polyether ether ketone (PEEK), ultra-high-molecular-weight (UHMW) polyethylene, polyetherimide, and polytetrafluoroethylene (PTFE).

18. The electrostatic machine of claim 1 , wherein the dielectric fluid further comprises a drag reducing agent selected from the group consisting of poly-isobutylene, polyethylene oxide, polyacrylamide, polysaccharides, surfactants, solid particle suspensions, and a combination of any two or more thereof.

19. The electrostatic machine of claim 18 , wherein the drag reducing agent is incorporated in the dielectric fluid from 1 to 1000 ppm.