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 .
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1-4 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Chen et al. (US 2021/0344188).
Regarding Claim 1, Chen discloses an electrical power system (1-5), comprising:
an electrical power source (source coupled to L1, L2, L3, not shown, Figures 1-4);
a DC electrical network (comprising 11, 12, Figures 1-4);
a power converter (comprising 10, Figures 1-4) comprising at least one input terminal (input terminal of 10 coupled to L1, L2, L3, Figures 1-4) and first and second DC output terminals (DC+, DC−) (output terminals connected to 11, 12, Figures 1-4C), the at least one input terminal connected to the electrical power source (input terminal of 10 coupled to L1, L2, L3, Figures 1-4C), the first and second DC output terminals connected to the DC electrical network (output terminals of 10 connected to 11, 12, Figures 1-4C);
a DC link capacitor (CDC) connected between the first and second DC output terminals (comprising C1, C2, Figures 1-4C);
a power semiconductor switch connected in series with the DC link capacitor between the first and second DC output terminals (part of 20, Figures 1-4C, transistor Q1 in 20, Figure 3); and
a control unit configured to respond to a fault in the DC electrical network by opening the power semiconductor switch (circuitry coupled to the gate of IGBT,Q1, Figure 3), whereby discharge of the DC link capacitor is prevented (Paragraph 54, “….if a short circuit event occurs and the full DC link voltage is applied to the transistor switch Q1, the collector current of Q1 increases to a level that drives the transistor switch Q1 out of the saturated region and into its linear region of operation. …. which is detected by the gate driver circuit 21 via filter 23. In response, the gate driver circuit 21 rapidly adjusts its output at pin 5 to turn off the transistor switch Q1”).
Regarding Claim 2, Chen discloses the electrical power system of Claim 1, wherein the control unit is configured to open the power semiconductor switch in response to a drop in a voltage (VDC) between the first and second DC output terminals (DC+, DC−) (Paragraph 54, “….if a short circuit event occurs and the full DC link voltage is applied to the transistor switch Q1, the collector current of Q1 increases to a level that drives the transistor switch Q1 out of the saturated region and into its linear region of operation. …. which is detected by the gate driver circuit 21 via filter 23…”).
Regarding Claim 3, Chen discloses the electrical power system of Claim 1, wherein the power semiconductor switch comprises: a depletion-mode MOSFET; or a JFET; or an arrangement comprising a pair of depletion-mode MOSFETs and anti-parallel diodes connected in series opposition (Paragraph 17, “….the transistor switch includes a FET, such as a MOSFET/SiC MOSFET,….).
Regarding Claim 4, Chen discloses the electrical power system of Claim 1, wherein the control unit is a hardware-implemented control unit (control circuit details shown in Figure 3).
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 5-10 are rejected under 35 U.S.C. 103 as being unpatentable over Chen et al. (US 2021/0344188) in view of Qiu et al. (US 2021/0234471).
Regarding Claim 5, Chen discloses the electrical power system of Claim 1, wherein the control unit comprises: a potential divider comprising a first resistor (R1) and a capacitor connected (R2) in series between a first terminal of the power semiconductor switch and second DC output terminals .(resistor R2 and capacitor C3, Figure 3), and the control circuit is configured to compare a voltage across the power semiconductor switch with a pre-determined threshold voltage, and to output a signal to the power semiconductor switch to open the power semiconductor switch if the voltage across the power semiconductor switch passes the pre-determined threshold voltage (Paragraph 55).
Chen does not disclose the a potential divider comprising the first resistor (R1) and a second resistor connected (R2) in series between the first and second DC output terminals (DC+, DC−), and a comparator configured to compare a voltage (VR2) across the second resistor with a pre-determined threshold voltage (VTH), and to output the signal to the power semiconductor switch to open the power semiconductor switch being if the voltage across the second resistor passes the pre-determined threshold voltage.
Qiu discloses an electrical power system (1-12), comprising:
an electrical power source (VAC, Figure 9);
a DC electrical network (comprising +VDC, ground/1 and the circuitry coupled across, Figure 9);
a power converter (comprising diode bride circuitry coupled to VAC input, Figure 9) comprising at least one input terminal and first and second DC output terminals (DC+, DC−), the at least one input terminal connected to the electrical power source, the first and second DC output terminals connected to the DC electrical network (output terminals of diode bridge connected to +VDC and ground and input terminals connected VAC, Figure 9);
a DC link capacitor (CDC) connected between the first and second DC output terminals (comprising Cin-LV, Cin-HV, Figure 9);
a power semiconductor switch connected in series with the DC link capacitor between the first and second DC output terminals (comprising Q1, Figure 9) and
a control unit configured to respond to a fault in the DC electrical network by opening the power semiconductor switch (circuitry with input connected between +VDC and ground and output coupled to a gate of Q1, Figure 9),
wherein the control unit comprises: a potential divider comprising a first resistor (R1) and a second resistor connected (R2) in series between the first and second DC output terminals (DC+, DC−) (comprising R2, R3 connected between +VDC and ground, Figure 9); and a comparator configured to compare a voltage (VR2) across the second resistor with a pre-determined threshold voltage (VTH) (comprising comparator LM397 with input connected between R2, R3 and output connected to the gate of Q1, VTH -200VDC, Figure 9), and to output a signal to the power semiconductor switch to open the power semiconductor switch if the voltage across the second resistor passes the pre-determined threshold voltage (see Figure 9 caption, when VDC >200V, Q1 is off). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide in the electrical power system of Chen, a resistor divider and comparator as taught by Qiu, to facilitate a simple, easy to implement voltage detection circuit.
Regarding Claim 6, combination of Chen and Qiu discloses the electrical power system of Claim 5, wherein the comparator comprises an operational amplifier (comparator LM397, Figure 9).
Regarding Claim 7, combination of Chen and Qiu does not specifically disclose the electrical power system of Claim 5, wherein a resistance of the first resistor (R1) is greater than a resistance of the second resistor (R2). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide in the combination, to set the relative resistances of the first and second resistors, such that a lower threshold can be set to compare the detected voltage (having smaller voltage drop across the second resistor compared to the first).
Regarding Claim 8, combination of Chen and Qiu discloses the electrical power system of Claim 5, wherein the control unit further comprises a voltage source configured to provide the pre-determined threshold voltage (VTH) as an input to the comparator (comprising capacitor connected to + input of the comparator, Figure 9) .
Regarding Claim 9, combination of Chen and Qiu discloses the electrical power system of Claim 8, wherein the voltage source comprises an energy storage device (comprising capacitor connected to + input of the comparator, Figure 9).
Regarding Claim 10, combination of Chen and Qiu discloses the electrical power system of Claim 8, wherein the voltage source comprises a potential divider connected across the DC link capacitor (CDC) (potential divider formed by the capacitor and resistor/s connected to the capacitor, Figure 9).
3. Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Chen et al. (US 2021/0344188) in view of Qiu et al. (US 2021/0234471) and Radecker et al. (US 5,615,100).
Regarding Claim 11, combination of Chen and Qiu does not specifically disclose the electrical power system of Claim 5, wherein the control unit further comprises a latch connected between an output of the comparator and the power semiconductor switch.
Radecker discloses a power semiconductor switch control circuitry (control circuitry for transistor 8, Figures 4-6) comprising a comparator (comprising 4, Figure 6) and a latch (comprising 11, Figure 6) connected between an output of the comparator and the power semiconductor switch (output UG/UT of latch 11 connected to the gate of transistor 8, Figures 5-6). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide in the combination, a latch as taught by Radecker, to set/reset the output to the power semiconductor switch based on the output of the comparator.
Claims 12-14 are rejected under 35 U.S.C. 103 as being unpatentable over Chen et al. (US 2021/0344188) in view of Newman, JR. et al. (US 2017/0311400).
Regarding Claim 12, Chen discloses the electrical power system of Claim 1, wherein the DC link capacitor (CDC) comprises a first capacitor (CDC1) and a second capacitor (CDC2) connected in parallel between the first and second DC output terminals (DC+, DC−), the power semiconductor switch being connected in series with only the first capacitor (C1, C2 in series with switch Q1 between 11, 12, Figure 3, C1, C2 in series with S1 connected between 11, 12, Figures 4A, 4B).
Chen does not disclose the first capacitor and the second capacitor connected in parallel.
Newman, JR. an electrical power system (Figures 1-8) comprising an electrical power source (comprising Vin, Figure 1); a DC electrical network (comprising DC network between 180, 140, Figures 1, 3); a power converter (comprising 120, 130, Figures 1, 3), wherein the DC link capacitor (CDC) comprises a first capacitor (CDC1) and a second capacitor (CDC2) connected in parallel between the first and second DC output terminals (DC+, DC− (comprising CIN, CBUS, CFILM connected between positive and negative DC bus, Figures 1, 3), and a power semiconductor switch being connected in series with only the first capacitor (a switch 192 connected in series with only CBUS, Figures 1, 3). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide in the electrical power system of Chen, an additional/parallel capacitor as taught by Newman, JR., for supplying high-frequency current that may be required to circulate through a power converter/a load regulation circuit coupled to a load (see Newman, JR, Paragraph 26).
Regarding Claim 13, combination of Chen and Newman, JR. discloses the electrical power system of Claim 12, wherein a capacitance of the first capacitor (CDC1) is greater than a capacitance of the second capacitor (CDC2) (Newman, JR., first capacitor being an electrolytic capacitor having a larger capacitance than the second film capacitor, Figures 1, 3).
Regarding Claim 14, combination of Chen and Newman, JR. does not specifically disclose the electrical power system of Claim 13, wherein the capacitance of the first capacitor (CDC1) is at least three times greater than the capacitance of the second capacitor (CDC2). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to select the capacitance of the first and second capacitors in the combination to a desired relative ratio, based on the operating parameters of the electrical power system.
Claims 15-18 are rejected under 35 U.S.C. 103 as being unpatentable over Chen et al. (US 2021/0344188) in view of Trainer et al. (US 2023/0373319).
Regarding Claim 15, Chen does not specifically disclose the electrical power system of Claim 1, wherein the control unit is further configured to, in response to a fault in the DC electrical network, cause the power converter to enter a crowbar configuration.
Trainer discloses an electrical power system (Figures 1-11) comprising an electrical power source (comprising 202, 203, Figure 2, 310, Figures 3A, 4A, 4B, 510, Figure 6B); a DC electrical network (330, Figures 3A, 4A, 4B, 530, Figure 6B); a power converter (comprising 205, 206, 207, Figure 2A, 320, , Figures 3A, 4A, 4B, 520, Figure 6B), a control unit (340, Figure 3A, 540, Figure 6B), wherein the control unit is further configured to, in response to a fault in the DC electrical network, cause the power converter to enter a crowbar configuration (Figure 6B, Paragraphs 85-86). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide in the electrical power system of Chen, a crowbar configuration as taught by Trainer to reduce fault current entering the DC network (see Trainer, Paragraph 85).
Regarding Claim 16, Chen discloses the electrical power system of Claim 1, wherein the electrical power source is an alternating power source (L1, L2, L3 connected to AC source, Figures 1-4C), and the power converter is an AC:DC power converter (10 converting AC to DC, 30 converting DC to AC, Figures 1-3).
Chen does not specifically disclose the electrical power source being a rotary electrical machine.
Trainer discloses an electrical power system (Figures 1-11) comprising an electrical power source (comprising 202, 203, Figure 2, 310, Figures 3A, 4A, 4B, 510, Figure 6B); a DC electrical network (330, Figures 3A, 4A, 4B, 530, Figure 6B); a power converter (comprising 205, 206, 207, Figure 2A, 320, Figures 3A, 4A, 4B, 520, Figure 6B), a control unit (340, Figure 3A, 540, Figure 6B), wherein the electrical power source is a rotary electrical machine (202 comprising a gas turbine engine 201 and electrical generator 211, Figure 2, Paragraphs 57-58, 310, Figures 3A, 4A, 4B, Paragraph 4, 510, Figure 6B,Paragraph 79), and the power converter is an AC:DC power converter (205, 206, Figure 2, 320, Figures 3A, 4A, 4B, 520, Figure 6B). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to include in the electrical power system of Chen, a rotary electrical machine as taught by Trainer, for use in electrical power system such as aircraft power system.
Regarding Claim 17, Chen does not specifically disclose the electrical power system of Claim 1, wherein the electrical power source is a DC power source, and the power converter is a DC:DC power converter.
Trainer discloses an electrical power system (Figures 1-11) comprising an electrical power source (comprising 202, 203, Figure 2, 310, Figures 3A, 4A, 4B, 510, Figure 6B); a DC electrical network (330, Figures 3A, 4A, 4B, 530, Figure 6B); a power converter (comprising 205, 206, 207, Figure 2A, 320, Figures 3A, 4A, 4B, 520, Figure 6B), a control unit (340, Figure 3A, 540, Figure 6B), wherein the electrical power source is a DC power source (battery pack 203, Figure 2), and the power converter is a DC-DC power converter (DC-DC converter 207, Figure 2). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide in the electrical power system of Chen, a DC power source as taught by Trainer, to have the advantage of a back-up power source.
Regarding Claim 18, Chen discloses the electrical power system of Claim 1 as discussed above. Chen does not specifically disclose an aircraft comprising the electrical power system.
Trainer discloses an aircraft comprising the electrical power system (Figures 200, 2A-2B, electrical power system details in Figures 3A-11) comprising an electrical power source (comprising 202, 203, Figure 2, 310, Figures 3A, 4A, 4B, 510, Figure 6B); a DC electrical network (330, Figures 3A, 4A, 4B, 530, Figure 6B); a power converter (comprising 205, 206, 207, Figure 2A, 320, Figures 3A, 4A, 4B, 520, Figure 6B), a control unit (340, Figure 3A, 540, Figure 6B). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide the electrical power system of Chen in an aircraft system that requires an electrical power system as taught by Trainer.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Bucher et al. (US 2021/0359591) discloses in Figure 1, a DC link capacitor 2 discharge circuit 8 and control circuit 19, 13 comprising a resistor divider circuit 13 connected across the DC link 5, 6 to detect voltage across the link with output connected to a comparator (output 14 connected comparator 25 input).
Any inquiry concerning this communication or earlier communications from the examiner should be directed to LUCY M THOMAS whose telephone number is (571)272-6002. The examiner can normally be reached Mon-Fri 9:30 am - 5:30 pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Crystal L Hammond can be reached at (571)270-1682. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/LUCY M THOMAS/Examiner, Art Unit 2838, 8/31/2026
/CRYSTAL L HAMMOND/Supervisory Primary Examiner, Art Unit 2838
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