Prosecution Insights
Last updated: April 19, 2026
Application No. 18/539,850

ELECTRIC DRIVE SYSTEM, CONTROL METHOD AND RELATED EQUIPMENT

Final Rejection §102§103
Filed
Dec 14, 2023
Examiner
ORTIZ, ELIM
Art Unit
2836
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
ZF Friedrichshafen AG
OA Round
2 (Final)
79%
Grant Probability
Favorable
3-4
OA Rounds
2y 11m
To Grant
99%
With Interview

Examiner Intelligence

Grants 79% — above average
79%
Career Allow Rate
449 granted / 567 resolved
+11.2% vs TC avg
Strong +23% interview lift
Without
With
+22.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
26 currently pending
Career history
593
Total Applications
across all art units

Statute-Specific Performance

§101
1.1%
-38.9% vs TC avg
§103
58.0%
+18.0% vs TC avg
§102
19.2%
-20.8% vs TC avg
§112
14.6%
-25.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 567 resolved cases

Office Action

§102 §103
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 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 1-8, 10, 11, 13-17 and 20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Liu (CN-108539833). Regarding claim 1, Liu an electric drive system (see Fig. 1), comprising a pair of inverters (see 4-1 and 4-2, Fig. 1) and an open winding motor (see 5, Fig. 1), wherein the pair of inverters comprises a first inverter connected to a battery (see 4-2, Fig. 1) and a second inverter connected to the first inverter (see 4-1, Fig. 1), and two terminals of a winding of each phase of the open winding motor are respectively connected to output terminals of bridge arms of corresponding phases of the pair of inverters (see connections of 4-1, 4-2 to motor 5, Fig. 1 ), wherein the electric drive system further comprises: a first switch connected between upper bridges of the pair of inverters (see 8-2, Fig. 1); and a control apparatus configured to control the inverters and switches of the electric drive system (see closed-loop control (Page 2/4) and claim 3, Fig. 1); and the electric drive system is configured with a boost charging mode, and the control apparatus is configured to control the first switch to be turned off, an upper bridge arm of the second inverter to be turned on and a lower bridge arm of the second inverter to be turned off, and a lower bridge arm and an upper bridge arm of a corresponding phase of the first inverter to be alternately turned on in the boost charging mode, such that a charging current first flows towards a winding of a corresponding phase of the open winding motor and then flows towards the battery through the winding of the corresponding phase of the open winding motor (operation of buck/boost mode using the control loop). Regarding claim 2, Liu teaches wherein when the lower bridge arm of the corresponding phase of the first inverter is turned on, a first direct current power supply apparatus connected in parallel to a distal side of the second inverter, an upper bridge arm of a corresponding phase of the second inverter, the winding of the corresponding phase of the open winding motor, and the lower bridge arm of the corresponding phase of the first inverter form a charging and energy storage loop; and when the upper bridge arm of the corresponding phase of the first inverter is turned on, the first direct current power supply apparatus, the upper bridge arm of the corresponding phase of the second inverter, the winding of the corresponding phase of the open winding motor, the upper bridge arm of the corresponding phase of the first inverter, and the battery form a boost charging loop (see para 0029 - 0034, Fig. 1 and 2). Regarding claim 3, Liu teaches wherein the electric drive system is further configured with a standard charging mode, and the control apparatus is configured to control the first switch to be turned on in the standard charging mode, such that the charging current flows towards the battery through the first switch (see para 0029 - 0034, Fig. 1 and 2). Regarding claim 4, Liu teaches the electric drive system according to claim 1 wherein the electric drive system is further configured with a boost discharging mode, and the control apparatus is configured to control the first switch to be turned off, an upper bridge arm of the first inverter to be turned on and a lower bridge arm of the first inverter to be turn off, and a lower bridge arm and an upper bridge arm of a corresponding phase of the second inverter to be alternately turned on in the boost discharging mode, such that a discharging current first flows towards a winding of a corresponding phase of the open winding motor from the battery and then flows out from the battery through the winding of the corresponding phase of the open winding motor (see para 0029 - 0034, Fig. 1 and 2). Regarding claim 5, Liu teaches wherein when the lower bridge arm of the corresponding phase of the second inverter is turned on, the battery, the upper bridge arm of the corresponding phase of the first inverter, the winding of the corresponding phase of the open winding motor, and the lower bridge arm of the corresponding phase of the second inverter form a discharging and energy storage loop and when the upper bridge arm of the corresponding phase of the second inverter is turned on, the battery, the upper bridge arm of the corresponding phase of the first inverter, the winding of the corresponding phase of the open winding motor, the upper bridge arm of the corresponding phase of the second inverter, and a first load apparatus connected in parallel to a distal side of the second inverter form a boost discharging loop (see para 0029 - 0034, Fig. 1 and 2). Regarding claim 6, Liu teaches wherein the electric drive system is further configured with a buck discharging mode, and the control apparatus is configured to control the first switch to be turned off, the upper bridge arm of the second inverter to be turned on and the lower bridge arm of the second inverter to be turned off, and the upper bridge arm and the lower bridge arm of the corresponding phase of the first inverter to be alternately turned on in the buck discharging mode, such that a discharging current first flows out from the battery towards the winding of the corresponding phase of the open winding motor and then flows out from the winding of the corresponding phase of the open winding motor (see para 0029 - 0034, Fig. 1 and 2). Regarding claim 7, Liu teaches wherein when the upper bridge arm of the corresponding phase of the first inverter is turned on, the battery, the upper bridge arm of the corresponding phase of the first inverter, the winding of the corresponding phase of the open winding motor, the upper bridge arm of the corresponding phase of the second inverter, and a second load apparatus connected in parallel to the distal side of the second inverter form a standard discharging loop; and when the lower bridge arm of the corresponding phase of the first inverter is turned on, the winding of the corresponding phase of the open winding motor, the upper bridge arm of the corresponding phase of the second inverter, the second load apparatus, and the lower bridge arm of the corresponding phase of the first inverter form a buck discharging loop (see para 0029 - 0034, Fig. 1 and 2). Regarding claim 8, Liu teaches further comprising: a capacitor connected in parallel to the distal side of the second inverter (see Cin, Fig. 1); and a second switch connected between the capacitor and the second inverter (see 8-1, Fig. 1), wherein the control apparatus is configured to control the second switch to be turned on in the charging mode and the discharging mode of the electric drive system (see 8-1, Fig. 1). Regarding claim 10, Liu teaches wherein the electric drive system is further configured with a dual-inverter drive mode; and the control apparatus is configured to control the first switch to be turned on, the second switch to be turned on or turned off, and the pair of inverters to jointly drive the open winding motor in the dual-inverter drive mode (see para 0029). Regarding claim 11, Liu teaches wherein the second switch is arranged at an end of the second inverter; or the second switch is arranged at an end of the capacitor (see 8-1, Fig. 1). Regarding claim 13, Liu teaches a control method used to control an electric drive system, comprising: controlling a first switch to be turned off, an upper bridge arm of a second inverter to be turned on, and a lower bridge arm of the second inverter to be turned off, and a lower bridge arm and an upper bridge arm of a corresponding phase of a first inverter to be alternately turned on through synchronous or asynchronous first PWM signals of each phase in response to connecting a first direct current power supply apparatus whose output voltage is lower than a voltage of a battery to a distal side of the second inverter, such that the electric drive system enters a boost charging mode in which the first direct current power supply apparatus first charges a winding of the corresponding phase of an open winding motor, and then charges the battery through the winding of the corresponding phase of the open winding motor (Please see rejection of claim 1). Regarding claim 14, Liu teaches further comprising: controlling the first switch to be turned off, the upper bridge arm of the first inverter to be turned on and the lower bridge arm of the first inverter to be turned off, and the lower bridge arm and the upper bridge arm of the corresponding phase of the second inverter to be alternately turned on through synchronous or asynchronous second PWM signals of each phase in response to connecting a first load apparatus whose load voltage is higher than the voltage of the battery to the distal side of the second inverter, such that the electric drive system enters a boost discharging mode in which the battery first discharges to the winding of the corresponding phase of the open winding motor and then discharges to the first load apparatus through the winding of the corresponding phase of the open winding motor (see para 0005 and 0024-0029, Fig. 2). Regarding claim 15, Liu teaches further comprising: controlling the first switch to be turned off, the upper bridge arm of the second inverter to be turned on and the lower bridge arm of the second inverter to be turned off, and the upper bridge arm and the lower bridge arm of the corresponding phase of the first inverter to be alternately turned on through synchronous or asynchronous third PWM signals of each phase in response to connecting a second load apparatus whose load voltage is lower than the voltage of the battery to the distal side of the second inverter, such that the electric drive system enters a buck discharging mode in which the battery first discharges to the second load apparatus through the winding of the corresponding phase of the open winding motor and then the winding of the corresponding phase of the open winding motor discharges to the second load apparatus (see para 0005 and 0024-0029, Fig. 2). Regarding claim 16, Liu teaches wherein the electric drive system further comprises a capacitor connected in parallel to the distal side of the second inverter and a second switch connected between the capacitor and the second inverter, wherein the second switch is controlled to be turned on in the charging mode and the discharging mode of the electric drive system; (see 8-1, Fig. 1) wherein the control method further comprises: in response to a single-inverter drive signal, controlling both the first switch and the second switch to be turned off, the second inverter to operate in an active short circuit mode, and the first inverter to operate in a single-inverter drive mode in which the first inverter drives the open winding motor alone through a first space vector pulse width modulation SVPWM signal; and in response to a dual-inverter drive signal, controlling the first switch to be turned on, the second switch to be turned on or turned off, and the two inverters to operate in a dual-inverter drive mode in which the two inverters jointly drive the open winding motor through second SVPWM signals (see para 0005 and 0024-0029, Fig. 2). Regarding claim 17, Liu teaches further comprising: synchronously controlling, according to power requirements, bridge arms of one phase, two phases, or three phases of the inverters operating in working modes, wherein the working modes comprise the charging mode, a discharging mode, and a drive mode (see para 0005 and 0024-0029, Fig. 2). Regarding claim 20, Liu teaches a control apparatus, comprising: a boost charging controller configured to: control a first switch to be turned off, an upper bridge arm of a second inverter to be turned on, and a lower bridge arm of the second inverter to be turned off, and a lower bridge arm and an upper bridge arm of a corresponding phase of a first inverter to be alternately turned on through synchronous or asynchronous first PWM signals of each phase in response to connecting a first direct current power supply apparatus whose output voltage is lower than a voltage of a battery to a distal side of the second inverter, such that the electric drive system enters a boost charging mode in which the first direct current power supply apparatus first charges the winding of the corresponding phase of an open winding motor, and then charges the battery through the winding of the corresponding phase of the open winding motor (Please see rejection of claim 1). 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 9, 18 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Liu in view of Saha et al (US 2021/0167702) Regarding claim 9, Liu teaches the electric drive system according to claim 8. Yet does not disclose wherein the electric drive system is further configured with a single-inverter drive mode; and the control apparatus is configured to control both the first switch and the second switch to be turned off, the second inverter to operate in an active short circuit mode, and the first inverter to drive the open winding motor alone in the single-inverter drive mode. However, Saha in the same filed teaches the electric drive system is further configured with a single-inverter drive mode; and the control apparatus is configured to control both the first switch and the second switch to be turned off, the second inverter to operate in an active short circuit mode, and the first inverter to drive the open winding motor alone in the single-inverter drive mode (see para 0042, 0043, 0084-0086 and 0111, Fig. 1), Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Liu with the teachings of Saha by having the electric drive system is further configured with a single-inverter drive mode; and the control apparatus is configured to control both the first switch and the second switch to be turned off, the second inverter to operate in an active short circuit mode, and the first inverter to drive the open winding motor alone in the single-inverter drive mode in order to allows the system to continue operating with reduced functionality, such as reduced torque or a single phase drive in some applications. Regarding claim 18 Liu teaches an electronic device, comprising: the control method according to claim 13. However, does not disclose a processor; and a memory storing executable instructions, wherein, when the executable instructions are executed by the processor. Yet, Saha in the same filed teaches a processor; and a memory storing executable instructions, wherein, when the executable instructions are executed by the processor (see para 0033 and 0034). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Liu with the teachings of Saha by having a processor; and a memory storing executable instructions, wherein, when the executable instructions are executed by the processor in order to allow controller to execute instructions and perform complex task in an automatic manner using a preset program. Regarding claim 19, Liu teaches an electronic device that performs the control method according to 13. However, does not disclose a non-transitory computer-readable storage medium storing program, wherein when the program is executed by a processor. Yet, Saha in the same filed teaches a non-transitory computer-readable storage medium storing program, wherein when the program is executed by a processor (see para 0033 and 0034). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Liu with the teachings of Saha by having a non-transitory computer-readable storage medium storing program, wherein when the program is executed by a processor in order to allow a controller to execute instructions and perform complex task in an automatic manner using a preset program. Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Liu in view of Toba (US 2015/0229252). Regarding claim 12, Liu teaches the electric drive system according to claim 8. However does not disclose wherein at least one of the second switch or the first switch is a power semiconductor switch. Yet, Toba in the same filed teaches at least one of the second switch and/or the first switch is a power semiconductor switch. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Liu with the teachings of Toba by having the second switch and/or the first switch is a power semiconductor switch in order to provide the ability to rapidly switch between states and control the flow of electricity with minimal power loss. Response to Arguments Applicant's arguments filed 8/11/2025 have been fully considered but they are not persuasive. Applicants general argument that Liu does not describe a control apparatus being configured to at least control a lower bridge arm and an upper bridge arm of a corresponding phase of the first inverter to be alternately turned on in the boost charging mode, such that a charging current first flows towards a winding of a corresponding phase of the open winding motor and then flows towards the battery through the winding of the corresponding phase of the open winding motor, the examiner respectfully disagrees. One skill in the art would clearly understand form Liu that during charge mode controls the state of the switching tubes of the upper bridge arm 4-1 of the three-phase voltage inverter and the lower bridge arm 4-2 of the three-phase voltage inverter or as stated by applicant are alternately turned on. During this control the open winding acts as an inductor in a buck/boost converter arrangement, a well-known operation. Where the inductor is charged and used to step up or step down the voltage in known operation. The current must flow into the winding an then by controlling the upper and lower bridges the direction of the current is controlled (i.e. flow into the motor windings and then flow the battery). This behavior is functionally equivalent and fully discloses a system and function as recited by applicants limitation without significant differences that are considered new. In fact Lui not only discloses the limitations but relies on the exact same inverter control strategy and current flow mechanism as described by applicant. Further any minor differences would flow naturally to one of ordinary skill in the art without an inventive step nor novelty. In conclusion the prior art Lui teaches all the limitations as disclosed in the office action. As highlighted above the method of charging the battery by controlling a lower bridge arm and an upper bridge arm of a corresponding phase of the first inverter to be alternately turned on in the boost charging mode, such that a charging current first flows towards a winding of a corresponding phase of the open winding motor and then flows towards the battery through the winding of the corresponding phase of the open winding motor is clearly disclosed by Lui. All other remarks are considered yet not found persuasive. Therefore, in order to expedite the prosecution of this application, The Examiner recommends that applicant amend the claims including structural components that are different from the prior art applied in order to distinguish the claim invention from the prior art of record. Conclusion THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to ELIM ORTIZ whose telephone number is (571)270-7114. The examiner can normally be reached 9:30am-6:30pm. 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. /ELIM ORTIZ/Examiner, Art Unit 2836
Read full office action

Prosecution Timeline

Dec 14, 2023
Application Filed
May 10, 2025
Non-Final Rejection — §102, §103
Aug 11, 2025
Response Filed
Aug 17, 2025
Final Rejection — §102, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
79%
Grant Probability
99%
With Interview (+22.9%)
2y 11m
Median Time to Grant
Moderate
PTA Risk
Based on 567 resolved cases by this examiner. Grant probability derived from career allow rate.

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