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.
Claim(s) 1-2, 10 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Burba et al. (US 6,388,451 B1, hereinafter "Burba").
Regarding claim 1, Burba discloses a leakage current compensator circuit comprising:
- a plurality of current carrying wires electrically coupled to a power supply and an electrical load (col. 3, lines 30-40: line voltages L1, L2 coupled between power source and electric vehicle load/charger), each of the power supply and the electrical load including a protective earth terminal (col. 3, lines 50-60: safety ground Gs connected to source and vehicle chassis/earth);
- a protective earth conductor electrically coupled to the protective earth terminal of the power supply and the protective earth terminal of the electrical load (col. 3, lines 50-60 safety ground Gs as protective earth conductor);
- a measurement circuit for measuring a leakage current in the plurality of current carrying wires (col. 3, lines 30-40: differential transformer 24 with sense winding 26 measures imbalance/leakage in L1, L2); and
- a current injector that is configured to apply a dynamic compensation current to the protective earth conductor, the current injector being electrically coupled to the plurality of current carrying wires (col. 3, lines 40-50: transistors Q1 and/or Q2 inject counter potential/current into safety ground Gs, coupled to L1, L2), wherein the current injector is configured to actively cancel the leakage current in the plurality of current carrying wires by injecting a compensation current into the protective earth conductor based on the output of the measurement circuit (col. 3, lines 50-600: Q1/Q2 conduct to induce reverse potential to Gs, canceling leakage based on sense winding output).
Regarding claim 2, Burba discloses wherein the measurement circuit comprises an open loop measurement coil or a closed loop measurement coil ((col. 3, lines 30-40: differential transformer 24 functions as a closed loop measurement coil via feedback to transistors).
Regarding claim 10, Burba discloses wherein the electrical load includes a non-isolated onboard charger for an electric vehicle (col. 1, lines 57-65: for electric vehicle charging without galvanic isolation).
Claims 11, 13-15 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Fluxa et al. (US 2014/0210411 A1, hereinafter "Fluxa").
Regarding claim 11, Fluxa discloses a method for compensating a leakage current in a grid-connected device, the grid-connected device being electrically connected to a plurality of current carrying wires and a protective earth conductor (¶ [0010]-[0011]: method for compensating leakage current in EV battery charger connected to phases, neutral, and electrical ground/protective earth), the method comprising:
- measuring a first leakage current in the plurality of current carrying wires based on the output of an open loop measurement circuit (¶ [0058]: active system includes leakage current detection circuit; passive/open loop implies initial measurement via expected leakage parameters);
- injecting a first compensation current into the protective earth conductor based on the measured first leakage current to provide an open loop leakage current reduction (¶ [0010]-[0011], [0058]: compensation current injected on electrical ground with opposite phase for passive/open loop reduction);
- measuring a second leakage current in the plurality of current carrying wires based on the output of a closed loop measurement circuit (¶ [0058]: electrical ground current measurement circuit measures residual after compensation); and
- injecting a second compensation current into the protective earth conductor based on the measured second leakage current to provide a closed loop leakage current reduction (¶ [0058]: control means adjusts compensation based on measured ground current, providing active/closed loop reduction).
Regarding claim 13, Fluxa discloses further including converting the second leakage current into an output voltage at a second transimpedance amplifier (¶ [0058]: measurement circuit implies conversion/amplification for control; ¶ [0044]-[0045]: voltage divider and components process signals).
Regarding claim 14, Fluxa discloses further including summing the output voltage of the first transimpedance amplifier and the output voltage of the second transimpedance amplifier at an input terminal of a band-pass summing amplifier (¶ [0058]: control means combines detection and measurement for adjustment; ¶ [0037]-[0038]: phase-shifting and summing via transformers and bridges for compensation).
Regarding claim 15, Fluxa discloses wherein the step of injecting a first compensation current and a second compensation current into the protective earth conductor is performed by a current injector having a first input terminal coupled to the output of the band-pass summing amplifier and having a second input terminal coupled to a virtual ground node (¶ [0037]-[0040]: injection via capacitors and switches to ground; ¶ [0045]: mid-point of voltage divider acts as virtual reference).
Claim Rejections - 35 USC § 103
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 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) 3-9, 12, 16-22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Burba et al. (US 6,388,451 B1, hereinafter "Burba"), in view of Fluxa et al. (US 2014/0210411 A1, hereinafter "Fluxa")
Regarding claim 3, Burba discloses the circuit of claim 1, but does not explicitly disclose each of an open loop measurement coil and a closed loop measurement coil, each including a current transformer with a toroid around the wires. Fluxa teaches dual aspects: passive/open loop compensation and active/closed loop with detection/measurement circuits (¶ [0058]: leakage detection and ground measurement circuits, implying separate sensing for initial and residual). Fluxa uses transformers for phase-shifting (¶ [0037]: toroid-like windings).
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify Burba's single transformer with Fluxa's dual open/closed loop measurements using transformers to provide combined passive and active control, enhancing precision and adaptability in leakage cancellation (Fluxa ¶ [0058]: adjust based on measurements for optimal reduction).
Regarding claim 4, the combination discloses the current injector electrically coupled between the open loop and closed loop measurement coils (Fluxa ¶ [0058]: compensation adjusted between detection and measurement points).
Regarding claim 5, the combination discloses outputs coupled to first/second transimpedance amplifiers (Fluxa ¶ [0058]: detection/measurement circuits imply amplification/conversion).
Regarding claim 6, the combination discloses outputs to band-pass summing amplifier with virtual ground (Fluxa ¶ [0037]-[0038]: summing via bridges; ¶ [0045]: mid-point as virtual ground).
Regarding claim 7, the combination discloses current injector coupled to summing amplifier output and virtual ground (Fluxa ¶ [0045]-[0046]: injection via capacitors to reference).
Regarding claim 8, the combination discloses grid configuration relays between wires and virtual ground (Fluxa ¶ [0048]-[0051]: switches for phase/neutral configuration).
Regarding claim 9, the combination discloses virtual ground control circuit (Fluxa ¶ [0045]: voltage divider controls reference).
Regarding claim 12, the combination discloses converting first leakage to output voltage at first transimpedance amplifier (per claim 5 rationale).
Regarding claim 16, Burba discloses a leakage current compensator system comprising:
- a measurement circuit for measuring a leakage current in a plurality of current carrying wires (col. 3, lines 30-40: differential transformer 24 with sense winding 26 measures imbalance/leakage in L1, L2);
- a current injector that is configured to apply a dynamic compensation current to a protective earth conductor, the current injector being electrically coupled to the plurality of current carrying wires (col. 3, lines 40-50: transistors Q1 and/or Q2 inject counter potential/current into safety ground Gs, coupled to L1, L2); and
- a processor coupled to the measurement circuit and the current injector (col. 3, lines 60-65: microprocessor senses leakage on each conductor independently and adjusts induced reverse potentials individually),
wherein the processor is configured to actively cancel the leakage current in the plurality of current carrying wires by injecting a compensation current into the protective earth conductor based on the output of the measurement circuit (col. 3, lines 50-60: Q1/Q2 conduct to induce reverse potential to Gs, canceling leakage based on sense winding output; col. 3, lines 60-65: microprocessor adjusts individually).
Burba does not explicitly disclose the processor including an open loop gain function and a closed loop gain function.
However, Fluxa teaches a processor including an open loop gain function and a closed loop gain function (¶ [0058]: control means adjusts operation according to estimated leakage currents (open loop) and measured ground current (closed loop), providing combined passive/active control for optimal reduction).
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify Burba's processor with Fluxa's open and closed loop gain functions to provide combined passive and active control, enhancing precision and adaptability in leakage cancellation (Fluxa ¶ [0058]: adjust based on measurements for optimal reduction).
Regarding claim 17, the combination discloses wherein the measurement circuit includes at least one current transformer having a toroid extending around the plurality of current carrying wires for output to the processor, the processor including at least one analog-to-digital converter (Fluxa ¶ [0037]: transformers for phase-shifting with toroid-like windings; Burba col. 3, lines 50-65: microprocessor implies digitization for independent sensing/adjustment).
Regarding claim 18, the combination discloses wherein the at least one current transformer comprises an open loop measurement coil and a closed loop measurement coil (Fluxa ¶ [0058]: leakage detection circuit (open loop) and ground current measurement circuit (closed loop), implying separate sensing).
Regarding claim 19, the combination discloses wherein the open loop gain function being based on the output of the open loop measurement coil, and the closed loop gain function being based on the output of the closed loop measurement coil (Fluxa ¶ [0058]: control means adjusts based on estimated (open) and measured (closed) levels).
Regarding claim 20, the combination discloses wherein the current injector includes a first input terminal coupled to an output of the processor and a second input terminal coupled to a virtual ground node (Fluxa ¶ [0045]-[0046]: injection via capacitors to mid-point reference/virtual ground; Burba col. 3, lines 40-50: transistors coupled via amplifier/microprocessor output).
Regarding claim 21, the combination discloses wherein the processor is configured to maintain a DC average of the virtual ground node to be the same as the protective earth conductor (Fluxa ¶ [0045]: voltage divider equalizes potentials at mid-point/virtual ground relative to electrical ground/protective earth).
Regarding claim 22, the combination discloses further comprising a plurality of grid configuration relays responsive to the processor for use with a three-phase electrical supply, a split-phase electrical supply, or a single-phase electrical supply (Fluxa ¶ [0048]-[0051]: switches/two-position relays for phase/neutral configurations in single/two/three-phase; Burba col. 3, lines 55-65: microprocessor control for adjustments).
Conclusion
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/TUNG X NGUYEN/ Primary Examiner, Art Unit 2858 12/11/2025