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 .
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
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, 3-4 and 8-9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al. CN107359800A (called Wang hereinafter and the examiner has provided a English machine translation) in view of Zhang et al. CN105606963A (called Zhang hereinafter and the examiner has provided a English machine translation).
Regarding independent claim 1, Wang teaches a current sensor (Fig. 1), comprising:
a main core (Fig. 1; core T2) and an auxiliary core (Fig. 1; core T1);
a primary winding (Fig. 1; primary winding N11) disposed on the main core and the auxiliary core (Fig. 1; para [0025]);
a secondary winding (Fig. 1; secondary winding N21) disposed on the main core and the auxiliary core (Fig. 1; para [0025]);
a compensation winding disposed on the auxiliary core (Fig. 1; para [0025]; compensation winding Nb);
a detection winding disposed on the main core (Fig. 1; para [0025]; detection winding Ne); and
a compensation circuit (Fig. 1; compensation unit 2) configured to acquire an alternating current (AC) signal (para [0027 and 0030]) induced by the detection winding (Fig. 1; para [0027 and 0030]) and apply a current signal to the compensation winding (Fig. 1; para [0027 and 0030]) based on the AC signal to make the compensation winding generate a reverse excitation electromotive force to adjust an excitation current in the current sensor (para [0027 and 0030]; the compensation winding inputs a magnetomotive force to reduce the conversion error from the input primary current to the secondary current).
Wang fails to teach to make the compensation winding generate a reverse excitation electromotive force to reduce an excitation current in the current sensor.
Zhang teaches to make the compensation winding generate a reverse excitation electromotive force to reduce an excitation current in the current sensor (para [0045).
Therefore, it would have been obvious to one skilled in the art before the effective filing date of the claimed invention to modify the structure as described Wang with the compensation method as described by Zhang for the purpose of introducing a closed-loop negative feedback and reducing excitation current to effectively control the excitation of the iron core (para [0045]).
Regarding claim 3, Wang and Zhang teach the current sensor of claim 1, Zhang further teaches wherein the compensation circuit is configured to reduce the excitation current to less than a preset value (para [0045]; when reducing the excitation current and minimal value has to be met to allow the excitation current to be reduced).
Regarding claim 4, Wang and Zhang teach the current sensor of claim 1, Wang further teaches wherein a magnitude of an induced potential in the compensation winding reflects a magnitude of the excitation current (Fig. 1; para [0027 and 0030]); and the compensation circuit is configured to determine a magnetic flux in the main core based on a magnitude of a voltage signal of the compensation winding to control a magnitude of an output compensation current (Fig. 1; para [0027 and 0030]).
Regarding claim 8, Wang and Zhang teach the current sensor of claim 1, the combination of Wang and Zhang further teaches further comprising a secondary load connected to the secondary winding (Zhang; Fig. 1; para [0047]; load resistor R3), wherein energy required by the secondary load is supplied by the auxiliary core (Zhang; Fig. 1; energy from core L2 through secondary winding N3), and zero magnetic flux is reached in the main core (para [0027 and 0030]; core T1 can be made to operate in a near-zero flux state).
Regarding independent claim 9, Wang teaches a control method (para [0006-0007]) of a current sensor (Fig. 1), wherein
the current sensor comprises a main core (Fig. 1; core T2) and an auxiliary core (Fig. 1; core T1); a primary winding (Fig. 1; primary winding N11) disposed on the main core and the auxiliary core (Fig. 1; para [0025]); a secondary winding (Fig. 1; secondary winding N21) disposed on the main core and the auxiliary core (Fig. 1; para [0025]); a compensation winding disposed on the auxiliary core (Fig. 1; para [0025]; compensation winding Nb); and a detection winding disposed on the main core (Fig. 1; para [0025]; detection winding Ne); and
the control method comprises acquiring an alternating current (AC) signal (para [0027 and 0030]) induced by the detection winding (Fig. 1; para [0027 and 0030]) and applying a current signal to the compensation winding (Fig. 1; para [0027 and 0030]) based on the AC signal to make the compensation winding generate a reverse excitation electromotive force to adjust an excitation current in the current sensor (para [0027 and 0030]; the compensation winding inputs a magnetomotive force to reduce the conversion error from the input primary current to the secondary current).
Wang fails to teach to make the compensation winding generate a reverse excitation electromotive force to reduce an excitation current in the current sensor.
Zhang teaches to make the compensation winding generate a reverse excitation electromotive force to reduce an excitation current in the current sensor (para [0045).
Therefore, it would have been obvious to one skilled in the art before the effective filing date of the claimed invention to modify the structure as described Wang with the compensation method as described by Zhang for the purpose of introducing a closed-loop negative feedback and reducing excitation current to effectively control the excitation of the iron core (para [0045]).
Claim(s) 2 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang, in view of Zhang and further in view of Gunn US2011/0156697.
Regarding claim 2, Wang and Zhang teach the current sensor of claim 1, but fail to teach wherein the primary winding passes through a middle of the main core and a middle of the auxiliary core in a through-core connection, and the secondary winding is wound around the main core and the auxiliary core.
Gunn teaches wherein the primary winding (Fig. 3; primary winding 12) passes through a middle of the main core (Fig. 3; first main core 10) and a middle of the auxiliary core (Fig. 3; sense core 11) in a through-core connection, and the secondary winding is wound around the main core and the auxiliary core (Fig. 3; measurement winding 13 wrapped around cores 10 and 11).
Therefore, it would have been obvious to one skilled in the art before the effective filing date of the claimed invention to modify the structure as described Wang and Zhang with the winding structure as described by Gunn for the purpose of accurate measurement of higher current or voltage signals for digital power measurement apparatus in AC power systems (para [0001]).
Allowable Subject Matter
Claim 5-7 and 10 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:
Regarding claim 5, the prior arts of record taken alone or in combination fail to teach or suggest:
“wherein the compensation circuit comprises a preamplifier circuit, a phase shift circuit, and a compensation current generation circuit; an input of the preamplifier circuit is connected to the detection winding, an input of the phase shift circuit is connected to an output of the preamplifier circuit, and the compensation current generation circuit is connected to an output of the phase shift circuit and connected to the compensation winding; the preamplifier circuit is configured to perform preamplification of the induced AC signal; the phase shift circuit is configured to perform phase-shifting processing on the AC signal and send the phase-shifted amplified AC signal to the compensation current generation circuit; and the compensation current generation circuit is configured to generate a compensation current and output the compensation current to the compensation winding to make the compensation winding generate the reverse excitation electromotive force.”
Claims 6-7 are indicated as allowable subject matter for depending on claim 5.
Regarding claim 10, the prior arts of record taken alone or in combination fail to teach or suggest:
“wherein the current sensor further comprises a compensation circuit, and the compensation circuit comprises a preamplifier circuit, a phase shift circuit, and a compensation current generation circuit; an input of the preamplifier circuit is connected to the detection winding, an input of the phase shift circuit is connected to an output of the preamplifier circuit, and the compensation current generation circuit is connected to an output of the phase shift circuit and connected to the compensation winding; the preamplifier circuit is configured to perform preamplification of the induced AC signal; the phase shift circuit is configured to perform phase-shifting processing on the AC signal and send the phase-shifted amplified AC signal to the compensation current generation circuit; the compensation current generation circuit is configured to generate a compensation current and output the compensation current to the compensation winding to make the compensation winding generate the reverse excitation electromotive force; the compensation circuit further comprises a secondary amplification circuit, a filter circuit, a microcontroller, and a digital potentiometer; an input of the secondary amplification circuit is connected to the output of the preamplifier circuit; an input of the filter circuit is connected to an output of the secondary amplification circuit; the microcontroller is connected to an output of the filter circuit, and the digital potentiometer is connected between the microcontroller and the compensation current generation circuit; and the control method comprises controlling, by the microcontroller, a magnitude of the compensation current by controlling a resistance value of the digital potentiometer.”
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Ferguson et al. discloses “Residual current monitoring type B with integrated self-test system and method” (see US2023/0184812)
Lenhard discloses “Compensation current sensor arrangement” (see US2014/0312892)
Fries et al. discloses “Current sensor” (see US2012/0314332)
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DAVID B FREDERIKSEN whose telephone number is (571)272-8152. The examiner can normally be reached M-F 8am - 5pm.
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/DAVID B FREDERIKSEN/Examiner, Art Unit 2858
/HUY Q PHAN/Supervisory Patent Examiner, Art Unit 2858
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