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 § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 20 rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 20 recites:
“determine that the current associated with the plurality of power switches exceeds a threshold current.”
However, claim 20 does not previously introduce “a current associated with the plurality of power switches.” The earlier language merely recites that the power switches are configured to “supply current to the motor.” It is unclear whether “the current associated with the plurality of power switches” refers to:
Aggregate inverter phase current; Current through only the first switch; Current through only the second switch; Combined branch current; DC-link current; Commanded motor current; or Measured motor winding current.
Accordingly, the scope of “the current” may be unclear.
Strength of this rejection
This is a weak-to-moderate rejection. MPEP §2173.05(e) explains that an express antecedent using identical words is not always necessary where the antecedent is reasonably ascertainable or inherent in an earlier-recited element. Applicant could persuasively argue that “supply current to the motor” supplies an implicit antecedent for “the current.”
A cleaner amendment would be:
“determine that a current associated with the plurality of power switches exceeds a threshold current.”
Claim Rejections - 35 USC § 102
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 1–5, 12, 14, and 17–20 are rejected under AIA 35 U.S.C. §102(a)(1) as anticipated by Saha et al., US 2018/0287510 A1.
Re Claim 1; Saha discloses a hybrid traction inverter for controlling an electric motor.
More specifically, Saha discloses power conversion device 1 positioned between DC power supply 11 and three-phase rotating electrical machine 80. Rotating electrical machine 80 serves as the driving-force source of a hybrid or electric vehicle, and inverter 10 converts DC power into three-phase AC power supplied to the motor. Saha, ¶¶[0027], [0035], Fig. 1.
Saha discloses:
a plurality of power switches configured to, in parallel, supply current to the electric motor of an electric vehicle, the plurality of power switches comprising a first power switch and a second power switch, the first power switch and the second power switch being of different types.
(Each phase arm includes upper and lower switch sections, and each switch section is a parallel circuit of first switching element 5 and second switching element 7. First switching element 5 is a Si-IGBT, whereas second switching element 7 is a SiC-MOSFET. Saha, ¶¶[0035]–[0036], Fig.
Saha discloses a controller configured to:
determine that a current associated with the plurality of power switches exceeds a threshold current.
Saha’s inverter control device receives measured phase-current information from current sensor 13 and selects switching patterns based on instantaneous values of phase currents Iu, Iv, and Iw. Pattern B applies when: ∣I1∣≤I<∣I2∣ and Pattern C applies when: ∣I2∣≤I<∣I3∣.
Thus, Saha determines whether the current equals or exceeds large-current reference value I2. Saha, ¶¶[0030], [0042]–[0043], [0051]–[0053], Figs. 4–8.)
responsive to determining that the current associated with the plurality of power switches exceeds the threshold current, control the plurality of power switches such that the first power switch turns on before the second power switch turns on during a switching cycle.
(When the phase current is equal to or greater than large-current reference value I2, Saha selects Pattern C. In Pattern C, first switching element 5 the Si-IGBT is turned on first, and second switching element 7 the SiC-MOSFET is turned on thereafter. Saha, ¶¶[0052]–[0057], Fig. 8.
Accordingly, Saha anticipates claim 1.)
Re Claim 2; Saha further discloses:
determine that the current associated with the plurality of power switches is less than the threshold current.
(Taking Saha’s large-current reference I2 as the claimed threshold, Saha identifies Pattern B for currents satisfying:
∣I1∣≤I<∣I2∣.
Thus, the current is less than threshold I2. The claim does not require that the claimed sequence occur for every possible current below the threshold; an operating subrange below the threshold satisfies the limitation. Saha, ¶¶[0042], [0046]–[0047], [0051].)
responsive to determining that the current associated with the plurality of power switches is less than the threshold current, control the plurality of power switches such that the second power switch turns on before the first power switch turns on during a second switching cycle.
(In Pattern B, second switching element 7 the SiC-MOSFET is turned on at time t1, and first switching element 5 the Si-IGBT is turned on later at time t3. Saha, ¶¶[0047]–[0049], Fig. 6.)
Re Claim 3 Saha discloses: a current sensor in communication with the controller, the current sensor configured to detect the current associated with the plurality of power switches.
(Current sensor 13 measures the currents flowing in the respective motor stator coils, and inverter control device 30 uses the measured currents for current-feedback control and switching-pattern selection. Saha, ¶¶[0029]–[0030], Fig. 1.)
Re Claim 4 Saha discloses the first power switch is an insulated gate bipolar transistor, and wherein the second power switch is a field effect transistor.
(First switching element 5 is expressly disclosed as a Si-IGBT, and second switching element 7 is expressly disclosed as a SiC-MOSFET. Saha, ¶[0036], Fig. 2.)
Re Claim 5; Saha discloses the first power switch is a silicon insulated gate bipolar transistor (Si IGBT), and wherein the second power switch is a silicon carbide metal oxide semiconductor field effect transistor (SiC MOSFET). That is the exact device combination disclosed in Saha ¶[0036].
Re Claim 12; Saha discloses responsive to determining that the current associated with the plurality of power switches exceeds the threshold current, the controller is configured to control the plurality of power switches such that the first power switch turns off after the second power switch turns off during the switching cycle.
(For Pattern C, selected when current equals or exceeds I2, Saha turns off second switching element 7 the SiC-MOSFET at time t14 and turns off first switching element 5 the Si-IGBTlater at time t16. Saha, ¶¶[0053], [0058], Fig. 8.)
Re Claim 14; Saha discloses responsive to determining that the current associated with the plurality of power switches is less than the threshold current, the controller is to control the plurality of power switches such that the second power switch turns off after the first power switch turns off during the second switching cycle.
(In Pattern B, which applies below threshold I2, first switching element 5 the Si-IGBT is turned off at time t5 and second switching element 7 the SiC-MOSFET is turned off later at time t6. Saha, ¶¶[0047], [0050], Fig. 6.)
Re Claim 17
Claim 17; recites the method corresponding to the apparatus of claim 1.
Saha performs a method of switching parallel, different-type power switches supplying current to a vehicle motor. The controller measures the phase current, determines that it equals or exceeds threshold I2, selects Pattern C, turns on first switching element 5 the Si-IGBT and subsequently turns on second switching element 7 the SiC-MOSFET. Saha, ¶¶[0030], [0036], [0042], [0052]–[0057], Figs. 1, 2, and 8.
Re Claim 18; Saha performs determining that the current associated with the plurality of power switches is less than the threshold current.
(For Pattern B, current is below I2. Saha then turns second switching element 7 the SiC-MOSFET on before first switching element 5 the Si-IGBT and turns the second switching element off after the first switching element. Saha, ¶¶[0047]–[0050], Fig. 6.)
Re Claim 19; Saha performs detecting the current associated with the plurality of power switches.
(Current sensor 13 detects motor-phase currents supplied through the inverter switch sections, and the controller uses the detected currents for feedback and switching-pattern control. Saha, ¶¶[0029]–[0030].)
Re Claim 20; Saha discloses An electric vehicle comprising: a motor; and a hybrid traction inverter configured to drive the motor.
Rotating electrical machine 80 is a driving-force source for a hybrid vehicle or electric vehicle, and inverter 10 supplies three-phase AC power to the machine. Saha, ¶[0027], Fig. 1.
The remainder of claim 20 the parallel different-type switches, current-threshold determination, and high-current sequence in which the first switch turns on before the second switch is disclosed for the reasons stated for claim 1. Saha, ¶¶[0036], [0042], [0052]–[0057], Figs. 2 and 8.
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.
Claims 6, 7, and 11 are rejected under AIA 35 U.S.C. §103 as unpatentable over Saha in view of Shinomiya et al., US 2019/0363706 A1.
Re Claim 6; Sara’s disclosure has been discussed above.
Saha does not expressly identify the names of the commonly connected power terminals.
Shinomiya expressly discloses:
an emitter of the Si IGBT is connected to a source of the SiC MOSFET, and wherein a collector of the Si IGBT is connected to a drain of the SiC MOSFET.
Specifically, Shinomiya states that the collector and emitter of IGBT 1 and the drain and source of SiC-MOSFET 2 are respectively commonly connected; the collector and drain are connected together toward the upper arm, and the emitter and source are connected together toward ground. Shinomiya, ¶[0156], Fig. 16.
It would have been obvious to employ this conventional parallel terminal arrangement in Saha’s parallel Si-IGBT/SiC-MOSFET switch section to cause both devices to conduct current between the same inverter nodes.
Re Claim 7; Saha discloses a processing circuit in the form of inverter control device 30 implemented using a microcomputer or DSP. The processing circuit receives current measurements, determines the applicable current range, selects the corresponding switching pattern, generates modulation pulses, and supplies independently generated switching-control signals S1 and S2 through drive circuit 40. Saha, ¶¶[0028]–[0030], [0034], [0039], [0042].
Thus, Saha teaches the claimed:
processing circuit configured to determine that the current associated with the plurality of power switches exceeds the threshold current, and generate a control signal and a pulse-width modulation (PWM) signal.
The current-dependent selection of Pattern C constitutes the control information specifying the first-before-second switching sequence, while the modulation pulse constitutes the PWM signal.
Sara does not necessarily disclose a gate drive integrated circuit (IC) configured to generate, based on the control signal and the PWM signal, (i) a first switching signal to switch the first power switch and (ii) a second switching signal to switch the second power switch, such that the first power switch is turned on before the second power switch is turned on during the switching cycle, and the first power switch is turned off after the second power switch is turned off during the switching cycle.
Shinomiya teaches implementing the downstream drive function as a driver IC. In Shinomiya:
Driver ICs receive a drive-control signal, such as PWM, from microcomputer 57;
The microcomputer receives current-sensor signal 58 and includes hardware timers for generating PWM;
The driver IC includes separate IGBT and MOS drive circuitry; and
Edge-detection and timer circuitry generates delayed, separate signals for the IGBT and FET. Shinomiya, ¶¶[0143]–[0149], [0157]–[0173].
Shinomiya’s IGBT starts turn-on first and the FET starts turn-on following expiration of the rising timer; at turn-off, the FET turns off first and the IGBT turns off after expiration of the falling timer. Shinomiya, ¶¶[0169]–[0173].
therefore, it would have been obvious to one of the ordinary skilled in the art before the effective filing of the invention to have implement Saha’s drive circuit 40 as Shinomiya’s gate-driver IC so that, based on Saha’s PWM and current-dependent switching-pattern selection, it generates:
A first switching signal for the Si-IGBT; and A second switching signal for the SiC-MOSFET,
with the first switch turning on before the second and turning off after the second.
Re Claim 11; Saha identifies first switching element 5 as a Si-IGBT and second switching element 7 as a SiC-MOSFET. Saha, ¶[0036].
Saha does not necessarily disclose the second power switch is a siliconcarbide metal oxide semiconductor field effect transistor (SiC MOSFET), and wherein a gate of the Si IGBT is driven by the first switching signal, and a gate of the SiC MOSFET is driven by the second switching signal.
Shinomiya expressly applies the separate IGBT-drive output to the gate of IGBT 1 and the separate MOS-drive output to the gate of FET 2. Shinomiya, ¶¶[0160]–[0162], Fig. 17.
therefore, it would have been obvious to one of the ordinary skilled in the art before the effective filing of the invention to have a gate of the Si IGBT is driven by the first switching signal, and a gate of the SiC MOSFET is driven by the second switching signal to adequately control the switching of the gate to effectively modulate the power transferred.
Claims 8, 9, and 13 are rejected under AIA 35 U.S.C. §103 as unpatentable over Saha and Shinomiya, further in view of Hussein et al., US 2012/0280728 A1.
Re Claim 8; Saha teaches the claimed ordering of the rising edges but does not state a numerical time separation i.e. wherein a rising edge of the first switching signal rises earlier than a rising edge of the second switching signal by an amount of time in a range from one hundred nanoseconds to ten microseconds during the switching cycle.
Hussein discloses that IGBT Q1 is turned on and IGBT Q2 is turned on 0.5 microsecond later. Hussein, ¶[0091], Figs. 10–12. A delay of 0.5 microsecond is 500 nanoseconds and Therefore lies within the claimed range from 100 nanoseconds to 10 microseconds.
therefore, it would have been obvious to one of the ordinary skilled in the art before the effective filing of the invention to have employ Hussein’s known 0.5-microsecond edge displacement as the time displacement between Saha’s first and second switching signals. Saha already requires the rising edges to be displaced; Hussein supplies a known, workable magnitude for that displacement. Selecting a known delay within a disclosed sequential-switching system would have been a predictable optimization of switching loss and transient performance.
Re Claim 9 Saha teaches turning off the second switch before the first switch in its high-current Pattern C. Hussein teaches a 0.5-microsecond displacement between the falling edges of parallel switches. Hussein, ¶¶[0091]–[0092], Figs. 10–15.
Therefore, it would have been obvious to one of the ordinary skilled in the art before the effective filing of the invention to have to use Hussein’s 0.5-microsecond displacement for Saha’s claimed falling-edge order. The resulting 500-nanosecond displacement falls within the claimed 100-nanosecond-to-10-microsecond range.
Re Claim 13; Saha does not state a numerical value for large-current reference I2. Saha does not disclose wherein the threshold current is above 100Amps
Hussein teaches selecting current thresholds based on the current rating of the parallel power devices. Threshold Ith2 is set slightly below maximum per-device current rating IR. Hussein further provides a worked example in which the main current rating/current through each device is 200 A and total current is 400 A. Hussein, ¶¶[0073], [0080], Fig. 4.
Therefore, it would have been obvious to one of the ordinary skilled in the art before the effective filing of the invention to have to select Saha’s threshold I2 above 100 A where the inverter employs traction-rated devices having approximately 200-A individual current capability. Current threshold selection is necessarily tied to device current capability, conduction loss, and safe current sharing. Hussein expressly teaches that relationship.
Claim 10 is rejected under AIA 35 U.S.C. §103 as unpatentable over Saha and Shinomiya, further in view of Heckroth et al., US 2022/0182004 A1.
Re Claim 10; Saha and Shinomiya teach PWM-controlled hybrid gate-driver operation but do not expressly state that the separate control and PWM signals are asynchronous.
Heckroth teaches a traction-inverter gate-driver system in which a separate SPI control transaction updating turn-on and turn-off working parameters is received asynchronously to the PWM signal. The gate driver subsequently synchronizes the parameter update internally to a suitable PWM transition. Heckroth, ¶¶[0091]–[0093], Fig. 14.
Therefore, it would have been obvious to one of the ordinary skilled in the art before the effective filing of the invention to have to provide Saha’s current-dependent switching-pattern control information asynchronously relative to its PWM signal, as taught by Heckroth, because doing so permits switching-sequence parameters to be updated independently of PWM generation while allowing the gate-driver IC to apply the new values safely at defined PWM edges.
Claims 15 and 16 are rejected under AIA 35 U.S.C. §103 as unpatentable over Saha and Shinomiya, further in view of Strydom, US 2022/0413535 A1.
Re Claim 15; Saha in view of Shinomiya disclosure has been discussed above. The combination does not disclose further comprising a high current drive circuit configured to boost the first switching signal to drive a gate of the first power switch and boost the second switching signal to drive a gate of the second power switch.
Strydom explains that a gate driver may be unable to provide sufficient gate current for a large power switch and therefore provides booster circuit 604/704 between the gate driver and power switch. The booster produces a scaled, higher-current replica of its input signal and supplies that output to the power-switch gate. Strydom, ¶¶[0037]–[0041], Figs. 6–7.
Therefore, it would have been obvious to one of the ordinary skilled in the art before the effective filing of the invention to provide one such booster channel for each of Saha’s first and second switching signals to increase the current available for charging and discharging the respective IGBT and SiC-MOSFET gates. The combination therefore teaches: “a high current drive circuit configured to boost the first switching signal to drive a gate of the first power switch and boost the second switching signal to drive a gate of the second power switch.”
Re Claim 16; Strydom teaches that the gate driver may be implemented as its own IC;
The booster may be discrete or a separate IC from the driver; The booster may be spatially isolated from the driver; and The booster package may include a thermally conductive exposed area soldered to a PCB. Strydom, ¶¶[0036]–[0040]. Thus, Strydom expressly teaches the high-current booster positioned external to the gate-driver IC and mounted on a PCB.
Although Strydom does not use the precise phrase “the gate-drive IC and booster are positioned on the same PCB,” mounting the electrically connected driver IC and external booster on the common inverter control PCB would have been an obvious packaging implementation. Such placement uses each component for its intended function, shortens the gate-drive interconnection, and implements Strydom’s express PCB-mounted, thermally separated booster arrangement.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DANIEL KESSIE whose telephone number is (571)272-4449. The examiner can normally be reached Monday-Friday 8am-5pmEst.
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.
/DANIEL KESSIE/
07/29/2026Primary Examiner, Art Unit 2836
Prosecution Insights