DETAILED ACTION
This action is responsive to the following communications: Application filed on 10/22/2024.
Claims 1-15 are presented for Examination. Claim 1 is independent.
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 1-2, 5-7, and 9-15 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Zheng (US 2017/0310256 A1).
Regarding independent claim 1, Zheng disclose that a method of controlling a brushless permanent magnet motor, the method comprising:
sequentially exciting and freewheeling a phase winding of the motor over a time interval between successive commutations of the phase winding (Fig.1:[0025]-[0026]), wherein exciting the phase winding comprises applying a voltage to the phase winding, and wherein freewheeling comprises freewheeling the phase winding for a respective freewheel period in response to a phase current flowing through the phase winding reaching a current threshold ( [0026]); and
determining the freewheel period such that the freewheel period increases between a start of the time interval and an end of the time interval ([0028], [0030], and [0035] describe decreasing commutation periods after each commutation with rotor acceleration, which necessarily results in corresponding adjustments to freewheel periods to maintain proper control timing).
Regarding claim 2, Zheng discloses determining the freewheel period such that the freewheel period increases sequentially within the time interval ([0030] and [0035] describe decreasing commutation periods after each sequential commutation).
Regarding claim 5, Zheng discloses that the difference is determined based at least in part on a time at which the next sequential freewheel period occurs within the time interval ([0030] and [0035] describe commutation periods dependent on rotor position and speed, with time-based adjustments).
Regarding claim 6, Zheng discloses that the method further comprising, within the time interval: measuring for each excitation of the phase winding, a parameter that depends on a rate of change of current in the phase winding during excitation or freewheeling ([0026]-[0027] describe measuring phase current at end of freewheel period); comparing a most recent parameter to a previous sequential parameter ([0026]-[0027] describe comparing measured phase current against saturation threshold); where a difference between the most recent measured parameter and the previous sequential parameter is below a threshold value ([0027] describes determination when phase current is less than saturation threshold); determining that a rotor of the brushless permanent magnet motor is at a pre-determined position ([0027]); and in response to determining that the rotor is at the predetermined position, commutating the phase winding ( [0028]-[0029]).
Regarding claim 7, Zheng discloses the sequentially exciting and freewheeling of the phase winding of the motor is conducted over a plurality of sequential time intervals, each time interval comprising a time interval between successive commutations of the phase winding, wherein a different polarity of voltage pulse is applied to the phase winding in two adjacent time intervals, and wherein at least some freewheel periods of a later one of the two adjacent time intervals are greater than at least some freewheel periods of an earlier one of the two adjacent time intervals ([0022]-[0023] and [0030] describe alternating current direction between commutations with adjusted timing parameters).
Regarding claim 9, Zheng discloses the method occurs during acceleration of the brushless permanent magnet motor ( [0008] and [0024]-[0025]).
Regarding claims 10-12, Zheng discloses a brushless permanent magnet motor comprising a phase winding and a controller configured to perform the recited method ([0013]-[0018]), an inverter and a current sensor with the current sensor located on a low-side of the inverter ([0022] and Fig. 1), and wherein freewheeling comprises freewheeling around the low-side of the inverter ([0020]-[0021]).
Regarding claims 13-15, Zheng discloses a data carrier comprising machine-readable instructions (inherent in microcontroller implementation described in paragraph [0046]), and appliances comprising the motor ( [0027]-[0028] describe applications such as vacuum cleaners and haircare appliances).
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 of this title, 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 3-4 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Zheng (US 2017/0310256 A1) in view of Bateman (US 2013/0234631 A1).
Regarding Claim 3, Zheng discloses most limitations as discussed above but does not explicitly disclose determining an initial freewheel period within the time interval based at least in part on a DC link voltage applied to the phase winding. However, Bateman teaches a method of controlling a brushless permanent magnet motor where control parameters are adjusted based on supply voltage ([0118]-[0121]). Specifically, Bateman teaches that changes in supply voltage affect current rise rates and thus control timing parameters must be adjusted accordingly to maintain accurate rotor position determination ([0118]-[0121]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Zheng to include determining initial freewheel periods based on DC link voltage, as taught by Bateman, to compensate for variations in supply voltage and maintain accurate rotor position determination and proper motor control (Bateman, [0118]-[0121]).
Regarding claim 4, Zheng discloses most limitations as discussed above but does not explicitly disclose that a difference between a previously determined freewheel period and a next sequential freewheel period increases within the time interval. However, Bateman teaches adjusting control parameters with progressive changes based on rotor position ( [0064]-[0065] and [0124]-[0127]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Zheng to include increasing differences between sequential freewheel periods, as suggested by Bateman's teachings on progressive parameter adjustment, to achieve smoother current profiles and improved motor efficiency while preventing current spikes that could damage components (Bateman, [0124]-[0127]).
Regarding claim 8, Zheng discloses most limitations as discussed above but does not explicitly disclose resetting the freewheel period at the end of each time interval. However, Bateman teaches resetting control parameters after commutation events to establish baseline conditions for the next control cycle ([0092]-[0093]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Zheng to include resetting freewheel periods at the end of each time interval, as taught by Bateman, to ensure proper initialization of control parameters for each new commutation cycle and prevent error accumulation that could lead to motor instability or component damage (Bateman, [0092]-[0093]).
Conclusion
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/MUHAMMAD S ISLAM/Primary Examiner, Art Unit 2837
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