1. A pressure sensor package, comprising:
a case for housing a pressure sensor chip;
a cover disposed on the case; and
a pressure inlet pipe for transmitting the pressure of a pressure medium to the pressure sensor chip, wherein
a groove is provided in a wall surface of a hole of the pressure inlet pipe.
2. The pressure sensor package according to claim 1, wherein
the groove is provided from an entrance of the pressure inlet pipe from which the pressure medium is introduced to a location in which it reaches the vicinity of the pressure sensor chip.
3. The pressure sensor package according to claim 1, wherein
the groove is provided parallel to the longitudinal direction of the pressure inlet pipe.
4. The pressure sensor package according to claim 1, wherein
the sectional form of the groove is a U-shaped type.
5. A pressure sensor, wherein
the pressure sensor chip is housed in the pressure sensor package according to claim 1.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for operating a doubly-fed induction generator (DFIG) having controllable line-side and rotor-side converters and at least one harmonic attenuating filter, comprising:
coordinating switching of the line-side converter with switching of the rotor-side converter to produce an interleaved switching pattern therebetween; and
wherein the interleaved switching pattern produces an effective increased switching frequency applied to the associated harmonic attenuating filter.
2. A method as in claim 1, wherein switching is coordinated so that the switching of the line-side converter and rotor-side converter are in opposite phasing.
3. A method as in claim 1, wherein switching of the line-side converter is configured to produce a continuously variable frequency offset from the rotor-side converter in coordination with the DFIG rotational frequency.
4. A method as in claim 3, wherein the offset is arbitrarily set to dynamically shift the phase angle of the line-side converter.
5. A method as in claim 3, wherein the line-side converter and rotor-side converters differ in synchronism by the frequency offset.
6. A doubly-fed induction generator (DFIG) system, comprising:
a DFIG having a stator bus and a rotor bus;
a line-side converter coupled to said stator bus by way of a line bus;
a rotor-side converter coupled to said line side converter and said rotor bus;
a controller coupled to said line-side converter and said rotor-side converter; and,
at least one harmonic attenuating filter,
wherein said line bus and stator bus are configured to be coupled to a power distribution grid, said at least one harmonic attenuation filter is configured to attenuate harmonics applied to the power distribution grid, and
wherein said controller is configured to coordinate switching of the line-side converter with switching of the rotor-side converter to produce an interleaved switching pattern therebetween.
7. A system as in claim 6, wherein said controller is configured to coordinate switching so that the switching of the line-side converter and rotor-side converter are in opposite phasing.
8. A system as in claim 6, wherein said controller is configured to coordinate switching of the line-side converter to produce a continuously variable frequency offset from the rotor-side converter in coordination with the DFIG slip frequency.
9. A system as in claim 8, wherein the controller is configured to arbitrarily set the offset to dynamically shift the phase angle of the line-side converter.
10. A system as in claim 8, wherein the controller is configured to maintain synchronization of the line-side converter and rotor-side converters differing by the frequency offset.
11. A method for reducing harmonic attenuation filter size in a doubly-fed induction generator (DFIG) system, comprising:
coordinating switching of a line-side converter with switching of a rotor-side converter to produce an interleaved switching pattern there between; and,
configuring at least one associated harmonic attenuating filter to attenuate harmonics based on an effectively increased switching frequency produced from the interleaved switching pattern.
12. A method as in claim 11, wherein switching is coordinated so that the switching of the line-side converter and rotor-side converter are in opposite phasing.
13. A method as in claim 11, wherein switching of the line-side converter is configured to produce a continuously variable frequency offset from the rotor-side converter in coordination with the DFIG slip frequency.
14. A method as in claim 13, wherein the offset is arbitrarily set to dynamically shift the phase angle of the line-side converter.
15. A method as in claim 13, wherein the line-side converter and rotor-side converters differ in synchronism by the frequency offset.