DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Election/Restrictions
Applicant’s election without traverse of Group I, claims 1-8 and 12-17 and Species X, Fig. 10 in the reply filed on 5/26/2026 is acknowledged.
Claim Objections
Claim 14 is objected to because of the following informalities: claim 14, dependent upon claim 1, recites a second iteration of “a DC network” which was previously claimed as a component within the power electronics converter of claim 1. Since the DC network has been previously introduced, the examiner will examine the claim as being directed towards the DC network as presented within claim 1. Appropriate correction is required.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1-3, 7-8, and 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (U.S. Patent Publication Number 2019/0067932) in view of Lin et al. (U.S. Patent Publication Number 2024/0405687).
Regarding Claim 1:
Li et al. discloses a power electronics converter (Fig. 3, circuit 10) comprising: an input terminal (Fig. 3, respective drive inputs 52 into rectifier circuit 56 as shown); first and second DC output terminals (Fig. 3, DC bus 64 having a first and second terminal output from rectifier 56 as shown; first and second DC output terminals read on by the upper bus and lower bus of DC bus 64 respectively); a branch comprising first and second semiconductor switches connected in series between the first and second DC output terminals (Fig. 3, solid-state switches 58 provided on a first phase leg 62 of the bridge corresponding to each of the three input phases as shown; see, at least, paragraph 0026), the input terminal connected to a node between the first and second semiconductor switches (Fig. 3, solid-state switches 58 provided on a first phase leg 62 of the bridge corresponding to each of the three input phases as shown wherein the input terminal connects to a node associated with the first set of solid-state switches 58 along the first phase leg 62; see, at least, paragraph 0026); a DC link capacitor connected between the first and second DC output terminals (Fig. 3, DC link capacitor bank 66 comprising one or more capacitors 68 across DC link 64 as shown; see, at least, paragraph 0027); a current sensor arranged to measure a current signal through the first or second DC terminals (Fig. 3, detection circuit 98 comprising current sensing circuit 102, and their related discussion; see, at least, paragraphs 0039-0043, etc. which disclose the detection circuit 98 including a current sensing circuit 102 that senses the current on each phase which is subsequently compared to one or more respective current thresholds by logic circuit 100); and a controller configured to provide switching signals to each of the first and second switches of the power electronics converter (Fig. 3, control system 96 and its related discussion; see, at least, paragraph 0038 which discloses the control system 98 functions to control the on/off switching of solid-state switches 58) , wherein the controller is further configured to detect a fault in a DC network connected between the first and second DC output terminals upon detection of a peak in an output from the current sensor above a first predetermined threshold (Fig. 3, control system 96, detection circuit 98 comprising current sensing circuit 102, and their related discussion; see, at least, paragraphs 0010, 0026-0028, 0038-0043, etc. which disclose control system 96 utilizing a current sensing circuit 102 of detection circuit 98 to measure, “three phase input currents or voltages, current at the switch level of rectifier circuit, DC link current, and/or load output currents…” and comparing the measured current value to a predetermined current threshold by logic circuit 100 to detect a fault condition “if the current is above the threshold value.”) and operate the first and second switches to prevent current flowing to the DC network (Fig. 3, control system 96, detection circuit 98 comprising current sensing circuit 102, and their related discussion; see, at least, paragraphs 0010, 0026-0028, 0038-0043, etc. which disclose upon detection of such a fault, the logic circuit 100 functions to implement a circuit breaking operation via selective switching of solid-state switches 58 to turn off and become non-conductive, thereby interrupting current flow). While Li discloses the utilization of a current sensor, Li fails to teach the current sensor as a differential current sensor.
However, Lin et al. discloses the utilization of a differential current sensor (Fig. 2, current sensor 14 and its related discussion; see, at least, paragraphs 0018, 0027, etc. which disclose the current sensor is a Rogowski coil configured to generate a current differential signal). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to realize the current sensor of Li as a differential current sensor, as taught within Lin, as the differential current sensor (in the form of a Rogowski coil) of Lin is a well-known current sensing device suitable for performing the current measurement operations described within Li, therefore representing a predictable design choice for carrying out the current-sensing functions of Li without changing the operation of the underlying system.
Regarding Claim 2:
Modified Li teaches the limitations of the preceding claim 1. Modified Li, in further view of Li, discloses further comprising a voltage sensor connected to measure a voltage across the DC output terminals (Fig. 3, detection circuit 98 comprising another sensing circuit 102 in the form of a voltage sampling circuit, i.e., voltage sensors, and its related discussion; see, at least, paragraphs 0038-0041, etc.), wherein the controller is configured to prevent current flowing to the DC network upon detection of the peak from the differential current sensor above the first predetermined threshold (Fig. 3, control system 96, detection circuit 98 comprising current sensing circuit 102, and their related discussion; see, at least, paragraphs 0010, 0026-0028, 0038-0043, etc. which disclose upon detection of such a fault, the logic circuit 100 functions to implement a circuit breaking operation via selective switching of solid-state switches 58 to turn off and become non-conductive, thereby interrupting current flow) and upon detection from the voltage sensor of the voltage across the DC output terminals falling below a second predetermined threshold (Fig. 3, detection circuit 98 comprising another sensing circuit 102 in the form of a voltage sampling circuit, i.e., voltage sensors, and its related discussion; see, at least, paragraphs 0038-0041, etc. which disclose comparing the voltage received from the voltage sampling circuit to a voltage threshold or limit such as an undervoltage threshold, and subsequently turn off the solid-state switches to become non-conductive, thereby terminating current flow).
Regarding Claim 3:
Modified Li teaches the limitations of the preceding claim 2. Modified Li, in further view of Li, discloses wherein the second predetermined threshold is around 60% or less of a nominal DC output voltage of converter (see, at least, paragraphs 0038-0041, etc. which disclose a nominal voltage may be 650V and the undervoltage threshold could be set to about 50-100V, i.e., about 8%-15%, which is less than 60% of the nominal voltage. The examiner further notes that discovering the optimum or workable ranges involves only routine skill in the art and that selecting a given threshold value relative to a nominal voltage of the system would have flown naturally to one of ordinary skill in the art as necessitated by the specific requirements of a given application).
Regarding Claim 7:
Modified Li teaches the limitations of the preceding claim 1. Modified Li, in further view of Lin, discloses further comprising an integrator connected to the differential current sensor (Fig. 2, integrator circuit 151 connected to current sensor 14, and their related discussion; see, at least, paragraph 0027), and configured to output a measure of change in current (ΔI) through the first or second DC terminals (Fig. 2, integrator circuit 151 connected to current sensor 14, and their related discussion; see, at least, paragraphs 0027-0028, etc. which disclose the integrator circuit 151 connected to the current sensor 14 for receiving the current differential signal and perform integration on the current differential signal), wherein the controller is configured to receive the measure of change in current (ΔI) and operate the first and second switches to prevent current flowing to the DC network upon detection of a peak in an output from the differential current sensor above a first predetermined threshold (Li: Fig. 3, control system 96, detection circuit 98 comprising current sensing circuit 102, and their related discussion; see, at least, paragraphs 0010, 0026-0028, 0038-0043, etc. which disclose upon detection of such a fault, the logic circuit 100 functions to implement a circuit breaking operation via selective switching of solid-state switches 58 to turn off and become non-conductive, thereby interrupting current flow) and if the measure of change in current (ΔI) is above a fourth predetermined threshold (Fig. 2, integrator circuit 151 connected to current sensor 14, and their related discussion; see, at least, paragraphs 0027-0028, etc. which disclose generating an upper threshold for subsequently causing generation of a modulation signal so as to further drive operation of the respective switches.).
Regarding Claim 8:
Modified Li teaches the limitations of the preceding claim 1. Modified Li, in further view of Lin, discloses wherein the differential current sensor comprises a Rogowski coil (Fig. 2, current sensor 14 and its related discussion; see, at least, paragraphs 0018, 0027, etc. which disclose the current sensor is a Rogowski coil configured to generate a current differential signal).
Regarding Claim 13:
Modified Li teaches the limitations of the preceding claim 1. Modified Li, in further view of Li, discloses comprising a plurality of said branches connected between the first and second DC output terminals (Fig. 3, solid-state switches 58 provided on a second phase leg 62 and a third phase leg 62 of the bridge corresponding to each of the three input phases as shown; see, at least, paragraph 0026), the node between the first and second semiconductor switches of each branch being connectable to a respective phase of an electrical machine (Fig. 3, solid-state switches 58 provided on the first, second, and third phase legs 62 of the bridge corresponding to each of the three input phases as shown connected to drive inputs 52 associated with an AC input; see, at least, paragraph 0026. The branches of Li are connected to respective phases of a three-phase drive input. Because the branches are configured to interface with respective phases of a three-phase AC power source, the branches are capable of being connected to corresponding phases of a three-phase electrical machine. Accordingly, the branches are “connectable” to a respective phase of an electrical machine as claimed. The examiner further notes that the claim does not positively recite the electrical machine as part of the apparatus, but instead recites only that the branches are connectable thereto.).
Claim(s) 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (U.S. Patent Publication Number 2019/0067932) in view of Lin et al. (U.S. Patent Publication Number 2024/0405687) and in further view of Li et al. (U.S. Patent Publication Number 2019/0067932; embodiment of Fig. 6A, hereinafter referred to as Li 6A).
Regarding Claim 4:
Modified Li teaches the limitations of the preceding claim 2. While Modified Li, in further view of Li, discloses wherein the controller is further configured to disconnect the DC network from the converter after detection of the peak from the differential current sensor (Fig. 3, control system 96, detection circuit 98 comprising current sensing circuit 102, and their related discussion; see, at least, paragraphs 0010, 0026-0028, 0038-0043, etc. which disclose upon detection of such a fault, the logic circuit 100 functions to implement a circuit breaking operation via selective switching of solid-state switches 58 to turn off and become non-conductive, thereby interrupting current flow) and detection from the voltage sensor of the voltage across the DC output terminals falling below the second predetermined threshold (Fig. 3, detection circuit 98 comprising another sensing circuit 102 in the form of a voltage sampling circuit, i.e., voltage sensors, and its related discussion; see, at least, paragraphs 0038-0041, etc. which disclose comparing the voltage received from the voltage sampling circuit to a voltage threshold or limit such as an undervoltage threshold, and subsequently turn off the solid-state switches to become non-conductive, thereby terminating current flow), Modified Li fails to teach wherein the controller is further configured to open contactors.
However, Li 6A discloses wherein the controller is further configured to open contactors to disconnect the DC network from the converter under such circumstances (Fig. 6A, disconnect switch 92 and its related discussion; see, at least, paragraph 0036 which discloses the control over contactors, read on by the disconnect switch(es) 92, to be open responsive to current and voltage conditions causing the solid-state switches to off or non-conducting). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Modified Li to incorporate an addition protection device, as taught within Li 6A, to provide additional protection thereby enabling use of the circuit within a variety of different applications.
Claim(s) 12 is/are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (U.S. Patent Publication Number 2019/0067932) in view of Lin et al. (U.S. Patent Publication Number 2024/0405687) and in further view of Chen et al. (U.S. Patent Publication Number 2009/0168276).
Regarding Claim 12:
Modified Li teaches the limitations of the preceding claim 1. Modified Li fails to teach further comprising a reverse-biased DC link diode connected across the DC link capacitor.
However, Chen et al. discloses a reverse-biased DC link diode connected across the DC link capacitor (Fig. 3A, diode 104 and its related discussion; see, at least, paragraphs 0034-0039, etc. which disclose the reverse polarization of protection diode 104 across from capacitor 110). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Modified Li to incorporate a reverse-biased DC link diode connected across the DC link capacitor, as taught within Chen, to protect the respective circuitry from damage caused by excessively high current levels, thereby improving protection for polarity-sensitive components through protection against voltage spikes, as well as improving overall reliability and longevity of the power electronics system.
Claim(s) 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (U.S. Patent Publication Number 2019/0067932) in view of Lin et al. (U.S. Patent Publication Number 2024/0405687) and in further view of Schult et al. (U.S. Patent Publication Number 2018/0287482).
Regarding Claim 14:
Modified Li teaches the limitations of the preceding claim 1. Modified Li, in further view of Li, discloses an AC power source (Fig. 3, AC power source for providing AC input power at drive inputs 52, and its related discussion; see, at least, paragraph 0026); a DC network (Fig. 3, DC network read on by the DC link capacitor bank 66 comprising one or more capacitors 68 across the respective DC outputs along the DC link or bus 64; see, at least, paragraphs 0010, 0026-0028, 0038-0043, etc.); and a power electronics converter according to claim 1 (see claim 1 as addressed above), wherein the AC power source is connected to the node of the power electronics converter (Fig. 3, solid-state switches 58 provided on the first, second, and third phase legs 62 of the bridge corresponding to each of the three input phases as shown connected to drive inputs 52 associated with an AC input; see, at least, paragraph 0026) and the DC network is connected across the first and second output terminals (Fig. 3, DC network read on by the DC link capacitor bank 66 comprising one or more capacitors 68 across the respective DC outputs along the DC link or bus 64; see, at least, paragraphs 0010, 0026-0028, 0038-0043, etc.). While Modified Li discloses an AC power source, Modified Li fails to teach the AC power source is an electrical machine.
However, Schult et al. discloses an electrical machine (Figs. 5-6, generator 4 and its related discussion; see, at least, paragraphs 0051-0052, etc. which disclose at least one generator associated with an aircraft for providing AC input power to a converter). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to realize the AC power source of Modified Li as an electrical machine, such as a generator, as shown within Schult, since generators are well-known electrical machines that produce three-phase AC power, thereby supplying three-phase AC power in a predictable manner.
Claim(s) 15-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (U.S. Patent Publication Number 2019/0067932) in view of Lin et al. (U.S. Patent Publication Number 2024/0405687) and in further view of Schult et al. (U.S. Patent Publication Number 2018/0287482) and in further view of Pan et al. (U.S. Patent Publication Number 2023/0086430).
Regarding Claim 15:
Modified Li teaches the limitations of the preceding claim 14. Modified Li, in further view of Schult, discloses an aircraft power and propulsion system (Figs. 5-6 and its related discussion; see, at least, paragraphs 0051-0052) comprising: a gas turbine engine (Figs. 5-6, engines 60 for driving generator 4 and their related discussion; see, at least, paragraphs 0036, 0051-0052, etc.); and an electrical power system according to claim 14 (see claim 14 as addressed above). Modified Li fails to teach wherein the electrical machine of the electrical power system is mechanically coupled with a spool of the gas turbine engine.
However, Pan et al. discloses wherein the electrical machine of the electrical power system is mechanically coupled with a spool of the gas turbine engine (Fig. 2, engine 140 coupled to generator 202 and their related discussion; see, at least, paragraph 0040 which discloses the generator may be coupled to the spool of engine 140). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to realize the electrical machine of Modified Li as being coupled with a spool of the gas turbine engine, as taught within Pan, to allow the electrical machine of Modified Li to be directly driven by an available rotating engine shaft, thereby providing a known and efficient source of mechanical power for electric power generation within an aircraft without changing the fundamental operation of the electrical machine.
Regarding Claim 16:
Modified Li teaches the limitations of the preceding claim 15. Modified Li, in further view of Pan, discloses an aircraft comprising the power and propulsion system of claim 15 (Fig. 2, and its related discussion; see also the rejection of claim 15 above. The examiner further notes that the claim appears to be redundant as claim 15 recites “an aircraft power and propulsion system” which appears to indicate that the power and propulsion system is already intended for use within an aircraft).
Regarding Claim 17:
Modified Li teaches the limitations of the preceding claim 16. Modified Li, in further view of Pan, discloses wherein the aircraft is a hybrid electric aircraft (Fig. 2 and its related discussion; see, at least, paragraphs 0004-0005, 0018, 0024, 0059, etc. which disclose the example aircraft as being a hybrid electric aircraft through utilization of a hybrid propulsion system).
Allowable Subject Matter
Claims 5-6 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter:
Dependent claim 5 is currently believed to be directed towards a non-obvious improvement over the prior art of record. While the prior art of record, namely Li, discloses a system configured to operate a converter to selectively turn on/off the respective solid-state switching devices responsive to detected currents and voltages compared to a threshold value, the prior art of record fails to appropriately teach or suggest “the controller is configured to operate the converter to turn on the semiconductor switches upon detection of the voltage across the DC output terminals falling below a third predetermined threshold lower than the second predetermined threshold” as currently presented. That is, while the prior art teaches it is known to selectively control the on/off operations of said switches, it appears as though such a modification to the prior art, namely Li, to turn on the semiconductor switches when the voltage across the DC output terminals falls below a third predetermined threshold lower than the second predetermined threshold would potentially teach away as the prior art intends for said switches, under such conditions, to remain in a non-conductive state to protect against a fault. For these reasons, inter alia, it appears as though, if claim 5 in its entirety, including all the claims from which it depends, were rewritten in independent form, said claim would be in condition for allowance. Dependent claim 6 is objected to as being dependent upon claim 5.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JOSEPH N INGE whose telephone number is (571)270-7705. The examiner can normally be reached 10:00-4:00 EST.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Rexford Barnie can be reached at 571-272-7492. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/JOSEPH N INGE/Examiner, Art Unit 2836
Prosecution Insights