DETAILED ACTION
This Office action is in response to the application filed on 07 January 2025.
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 § 101
35 U.S.C. 101 reads as follows:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
Claims 13, and 14 are rejected under 35 U.S.C. 101 because the claimed invention is directed to non-statutory subject matter.
Claims 13, and 14 are directed to a computer program, which is interpreted to encompass computer software per se that does not fall into any of the four statutory categories of invention.
As explained in MPEP 2106.03, sec. I:
“a product claim to a software program that does not also contain at least one structural limitation ... has no physical or tangible form, and thus does not fall within any statutory category”.
See also Microsoft Corp. v. AT&T Corp., 550 U.S. 437, 449, 82 USPQ2d 1400, 1407 (2007).
An examiner suggests that the applicant deletes claim 14 and changes claim 13 so that the preamble is "A non-transitory computer-readable storage medium storing a computer program for controlling an electrical converter ...".
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 1-12, and 15-17 are rejected under 35 U.S.C. 103 as being unpatentable over Al-Hokayem Peter et. al (EP3058646A1; hereafter “Peter”) in view of Martin Veenstra et. al (IEEE Transactions on Industry Applications; hereafter “Martin”).
-Regarding claim 1:
Peter discloses:
A method for controlling an electrical converter (Fig. 1; 12, and description; “The invention relates to a method for controlling an electrical converter and a converter system.”) , a pattern determination part comprising the following: selecting and reading an offline-computed optimized pulse pattern from a database, wherein the selected optimized pulse pattern comprises switching instants for the main stage and the filter cells over a next computation window of a predetermined width (detailed description; “The core of MP3C is an online computational stage that adjusts the switching instants in the OPPs so as to maintain the flux on the reference trajectory in closed-loop.”, and “The optimized pulse pattern and the corresponding switching instants are the control input u for the converter”); and predictive control part (detailed description; “The control method of the inner control loop may be MP3C, which may be provided with information”) comprising the following, which are performed several times during the next computation window modifying the adjusted optimized pulse patterns (paragraph IV; “be solvable in a reasonable amount of time (compared with plant dynamics) necessitates the use of a suitable optimization algorithm along with an appropriate problem formulation”) by moving at least one transition time of a switching instant, such that a flux error determined from a difference between an estimated flux of the electrical converter and a reference flux trajectory is minimized (back ground; ”a flux error may be set to a difference of the reference flux and a sum of the estimated flux and the corrective flux”, and “the second cost function penalizes the flux error, which is dependent on the corrective flux determined by the outer control loop.”) and applying at least a next switching instant from the modified adjusted pulse pattern to the electrical converter (detailed description; “The switching instants cannot be modified arbitrarily. For the three phases, the set of constraints is imposed, which constrains the switching instants in two ways. Firstly, by the current time-instant kTs, i.e. transitions cannot be moved into the past. Secondly, by the neighboring switching transitions in the same phase, ensuring that the correct sequence of switching transitions is kept.”).
However, Peter does not an electrical converter with an optimized pulse pattern.
Martin, in the same field of endeavor, discloses:
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“the electrical converter (Fig. 3) comprising a main stage having an output comprising at least three phases of an intermediate voltage (Fig. 3; NPC inverter mixed with series connected H-bridge inverter), the main stage (Fig. 3; blue arrow) configured to convert a DC voltage into the intermediate voltage, the intermediate voltage comprising at least two voltage levels, and a filter cell stage (Fig. 4) with a filter cell (Fig. 3; red arrow) for each phase of the main stage (Fig. 3; blue arrow), each filter cell (Fig. 3; red arrow) configured to add or subtract a cell voltage of the filter cell (Fig. 3; red arrow) to the intermediate voltage…”
“adjusting the optimized pulse pattern (paragraph IV; “be solvable in a reasonable amount of time (compared with plant dynamics) necessitates the use of a suitable optimization algorithm along with an appropriate problem formulation”) by moving its switching instants such that average output voltages generated in the filter cells (Fig. 3; red arrow) are shifted towards an average output voltage reference of the filter cells (abstract; “Power balancing is guaranteed by varying the common-mode voltage, using an online nonlinear model-predictive controller. The controller predicts the system evolution as a function of the control inputs. A cost function of system and control quantities is iteratively minimized in real time, to find the optimal control to apply to the system.”, where Peter explained the cost function can be minimized by moving time instant), which is determined from measurements in the filter cells (Fig. 3; red arrow), and compensating these adjustments by corresponding modifications of switching instants of the main stage, wherein the average output voltage reference has at least three phases (paragraph V; ”The three subinverter intermediate-circuit voltages and the main-inverter neutral-point voltage are stabilized by varying the common-mode component. The algorithm predicts the evolution of those voltages as a function of this component, utilizing a load and an inverter model.”); .…”
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 device described in Peter such that a commonly used control of a hybrid asymmetric multilevel inverter described in Martin is applied to method for controlling electrical converter. Doing so allows for improving the control of multilevel switching converter.
-Regarding claim 15:
Peter discloses:
A controller (Fig. 5 ; 28) for configured to control an electrical converter, pattern determination controller (Fig. 5; 28) configured to: select and read an offline-computed optimized pulse pattern from a database, wherein the selected optimized pulse pattern comprises switching instants for the main stage and the filter cells (detailed description; “The core of MP3C is an online computational stage that adjusts the switching instants in the OPPs so as to maintain the flux on the reference trajectory in closed-loop.”, and “The optimized pulse pattern and the corresponding switching instants are the control input u for the converter”) over a next computation window of a predetermined width; and model predictive controller (Fig. 5; 28) configured to: modify the adjusted optimized pulse patterns by moving at least one transition time of a switching instant, such that a flux error determined from a difference between an estimated flux of the electrical converter and a reference flux trajectory is minimized (back ground; ”a flux error may be set to a difference of the reference flux and a sum of the estimated flux and the corrective flux”, and “the second cost function penalizes the flux error, which is dependent on the corrective flux determined by the outer control loop.”); and apply at least a next switching instant from the modified adjusted pulse pattern to the electrical converter (detailed description; “The switching instants cannot be modified arbitrarily. For the three phases, the set of constraints is imposed, which constrains the switching instants in two ways. Firstly, by the current time-instant kTs, i.e. transitions cannot be moved into the past. Secondly, by the neighboring switching transitions in the same phase, ensuring that the correct sequence of switching transitions is kept.”).
However, Peter does not an electrical converter with an optimized pulse pattern.
Martin, in the same field of endeavor, discloses:
“the electrical converter having a main stage having an output comprising at least three phases of an intermediate voltage, and a filter cell stage with a filter cell for each phase of the main stage (Fig. 3; NPC inverter mixed with series connected H-bridge inverter),”
“adjust the optimized pulse pattern by moving its switching instants such that average output voltages generated in the filter cells are shifted towards an average output voltage reference of the filter cells (abstract; “Power balancing is guaranteed by varying the common-mode voltage, using an online nonlinear model-predictive controller. The controller predicts the system evolution as a function of the control inputs. A cost function of system and control quantities is iteratively minimized in real time, to find the optimal control to apply to the system.”, where Peter explained the cost function can be minimized by moving time instant), which is determined from measurements in the filter cells, and compensate for these adjustments by corresponding modifications of switching instants of the main stage (paragraph V; ”The three subinverter intermediate-circuit voltages and the main-inverter neutral-point voltage are stabilized by varying the common-mode component. The algorithm predicts the evolution of those voltages as a function of this component, utilizing a load and an inverter model.”);”
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 device described in Peter such that a commonly used control of a hybrid asymmetric multilevel inverter described in Martin is applied to method for controlling electrical converter. Doing so allows for improving the control of multilevel switching converter.
-Regarding claim 2:
Martin discloses:
The method of claim 1, wherein each phase of the average output voltage reference (Fig. 7) corresponding to a filter cell is based on a difference of a measured capacitor voltage signal of the filter cell and a reference capacitor voltage of the filter cell (paragraph V: ” The aim of the algorithm is to keep the capacitor voltages close to their reference values, their control errors and..” , and foot note 6; “Control errors are the difference between the reference and the actual value of controlled variables.”).
-Regarding claim 3:
Peter discloses:
The method of claim 1, the pattern determination part (Fig. 5; 28) further comprising: determining the reference flux trajectory over the next computation window from the adjusted optimized pulse pattern (background; “The OPPs are used to generate reference flux trajectories that are to be followed. MP3C comprises an online computational stage that adjusts the switching instants in the OPPs so as to maintain the flux on the reference trajectory in closed-loop.”).
-Regarding claim 4:
Peter discloses:
The method of claim 1, wherein the main stage of the electrical converter comprises a DC link (background; “the converter system may be an electrical drive with an inverter that is adapted for supplying an electrical motor with AC current generated from a DC link. The filter may be interconnected between the inverter and the motor. In this case”); and wherein the method further comprises adjusting the optimized pulse pattern in the pattern determination part (Fig. 5; 28) of the method by moving the switching instants of the optimized pulse pattern such as to shift a measured voltage difference between an upper and a lower DC link voltage to a reference neutral point voltage (detailed description; “In particular, the estimator module receives or computes the inverter output voltage vi (possibly by reconstructing it based on the DC link voltage and the switching instants of the control input u). Furthermore, it may receive the measured inverter current i, and the filter capacitor current”, where estimate module relates with OPP, see Fig. 5, and Fig. 8).
-Regarding claim 5:
Peter discloses:
The method of claim 1, wherein; the selected optimized pulse pattern is a single-phase pulse pattern, and the pattern determination part (Fig. 5; 28) of the method comprises generating a multiple-phase optimized pulse pattern from the single-phase optimized pulse pattern and carrying out the adjustments for each phase separately (detailed description; “the converter system 10 also may be a single phase system. The inverter 12 produces an N-level output voltage, which is smoothed by the LC filter 14, which comprises a filter inductor Lf connected between the converter 12 and the rotating electrical machine 16. A filter capacitor Cf is connected in parallel to the converter 12 and/or rotating electrical machine 16. It has to be understood that in a multi-phase system, the filter inductor Lf and filter capacitor Cf (as well as the components described below) comprise a number of physical inductors and capacitors corresponding to the number of phases.”).
-Regarding claim 6:
Peter discloses:
The method of claim 1, wherein: the selected optimized pulse pattern is a total optimized pulse pattern comprising cumulative switching instants for the main stage and the filter cells (detailed description; ”The optimized pulse pattern and the corresponding switching instants are the control input u for the converter 12.” ,and “MP3C is an online computational stage that adjusts the switching instants in the OPPs so as to maintain the flux on the reference trajectory in closed-loop.”); and the pattern determination part of the method further comprises parsing each optimized pulse pattern into a main pulse pattern for the main stage and a cell pulse pattern for the filter cell of the respective phase (detailed description; “This may be accomplished by updating a pointer to the look-up table that stores the switching triggers of the OPP and the respective three- phase potential values.”), prior to carrying out the adjustments.
-Regarding claim 7:
Peter discloses:
The method of claim 1, further comprising: determining whether a flux reference angle is within the computation window (detailed description; “the torque controller 44 then determined the angle or phase < ij;1 of the reference inverter flux ip;,”) ; generating a trigger signal if the flux reference angle leaves the computation window (detailed description; “This may be accomplished by updating a pointer to the look-up table that stores the switching triggers of the OPP and the respective three- phase potential values.)
; and triggering the pattern determination part (Fig. 5; 28) of the method by the trigger signal.
-Regarding claim 8:
Peter discloses:
The method of claim 1, wherein: the computation window is a fixed range of angles with respect to the optimized pulse pattern, and the computation window is a time period corresponding to at least 1/6 of a fundamental period of a reference output voltage of the electrical converter (detailed description; “the torque controller 44 then determined the angle or phase < ¾/)■ of the reference inverter flux ΨΙ he inverter torque T, can be written as Tt “).
-Regarding claim 9:
Peter discloses:
The method of claim 1, wherein: the pattern determination part of the method is performed by a pattern determination controller (Fig. 5; 28), and the model predictive control part of the method is performed by a model predictive controller, which has a faster execution speed than the pattern determination controller (detailed description; “The MP3C controller 38 comprises a speed controller (module)”, and “The speed controller 42 determines a so-called reference inverter torque T^from the difference of a reference speed ) ωΒ* and an estimated speed ) <¾ provided by the estimator”).
-Regarding claim 10:
Peter discloses:
The method of claim 1, wherein, when a fundamental flux reference is outside an angle range provided by the reference flux trajectory, the flux error is determined from a difference between the estimated flux of the electrical converter and a circular flux trajectory (background; “electrical converter may be determined or received and a flux error may be set to a difference of the reference flux and a sum of the estimated flux and the corrective flux.”, and “the flux error, which is dependent on the corrective flux determined by the outer control loop.”).
-Regarding claim 11:
Peter discloses:
The method of claim 1, wherein the adjusted optimized pulse pattern and the flux reference trajectory are stored in a look-up table (detailed description; “the look-up table that stores the switching triggers of the OPP and the respective three- phase potential values.”) during the pattern determination part.
-Regarding claim 12:
Peter discloses:
The method of claim 1, wherein the adjusted optimized pulse pattern and the flux reference trajectory are calculated and stored in a look-up table (detailed description; “the look-up table that stores the switching triggers of the OPP and the respective three- phase potential values.”) during the pattern determination part (Fig. 5; 28) for the next two computation windows (I would say that the selection of a computation window is well-within the skill of the person of ordinary skill in the art. I would then come up with a motivation to choose two computation windows and give that as the rationale.).
-Regarding claim 16:
Martin discloses:
The controller according to claim 15, wherein the electrical converter (Fig. 3) is configured such that [[a]]the mainstage is configured to convert a DC voltage into [[an]] the intermediate voltage, the intermediate voltage comprising at least two voltage levels[[;]] (Fig. 3; NPC inverter mixed with series connected H-bridge inverter, and Fig. 4).
-Regarding claim 17:
Martin discloses:
The controller according to claim 15, wherein the electrical converter is configured such that the filter cell stage is configured to add or subtract a cell voltage of the filter cell to the intermediate voltage (Fig. 4; Tree of possible phase output voltages of the hybrid inverter. For the main inverter (cell 1), three branches are drawn, corresponding to its three possible voltages 3, 0, and +3. At each of these three values, we have the three possible voltages of the subinverter (cell 2) 1, 0, and +1, resulting in nine different output voltages.).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SEUNG HO CHOI whose telephone number is (571)272-8188. The examiner can normally be reached Monday-Thursday, 7:30 AM - 5:30 PM ET.
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/SEUNG HO CHOI/Examiner, Art Unit 2838
/CRYSTAL L HAMMOND/Supervisory Primary Examiner, Art Unit 2838
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