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 § 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) 1-10 are rejected under 35 U.S.C. 103 as being unpatentable over Gao et al. (EP 4199293)
Re Claim 1; Gao discloses a power converter comprising (Fig. 3, ¶0012):
an inverter, comprising: an inverter circuit; at least one switching module; and a controller,
Gao teaches a power converter including a power conversion circuit (inverter circuit), a switching device (comprising first-stage and second-stage switching modules), and a controller (¶0012, ¶0024, Fig. 3).
wherein an input end of the inverter circuit is configured to connect a direct-current (DC) source,
Gao discloses that the input end of the power conversion circuit is connected to a direct current power supply (¶0012, ¶0022).
an output end of each phase of the inverter circuit is connected to a corresponding switching module of the at least one switching module,
Gao teaches that each phase of the inverter circuit connects to a corresponding switch in the switching module (¶0012, Fig. 3).
and an output end of the at least one switching module is configured to connect a power grid;
Gao discloses that the switching modules are connected in series between the inverter and the AC power grid (¶0012, ¶0024).
the controller is configured to:
Gao teaches a controller that manages grid connection and disconnection, fault detection, and switching control (¶0012, ¶0024, ¶0030, ¶0047).
perform pulse blocking on the inverter circuit in response to a short circuit of a negative electrode of the DC source to ground, wherein the pulse blocking comprises disabling a drive pulse for each switching transistor in the inverter circuit;
Gao teaches that the controller detects short circuit faults at the input or output of the inverter and disconnects the inverter from the grid (¶0030, ¶0047). While the term “pulse blocking” is not used, the act of disconnecting the inverter implies disabling drive signals to the switching transistors to prevent further conduction.
determine whether a first current of a switching module of the at least one switching module at a current time instant is less than or equal to a first preset current after the inverter circuit is subjected to the pulse blocking, wherein the first preset current is greater than or equal to a safe current of the switching module;
Gao teaches current monitoring and control based on output currents in each phase (¶0016, ¶0028, ¶0044–¶0046). Although the term “first preset current” is not explicitly used, the logic of comparing current values to thresholds is inherent in the zero-crossing and delay-based control.
determine a current change trend of the switching module at the current time instant in response to the first current of the switching module being less than or equal to the first preset current;
Gao teaches determining current change trends based on zero-crossing detection and timing logic (¶0018–¶0019, ¶0028–¶0029, ¶0044–¶0046).
and turn off the switching module in response to the current change trend being a descending trend;
Gao teaches turning off switching modules based on current behavior, particularly at zero-crossing moments to avoid contact adhesion and current shock (¶0018, ¶0028, ¶0045).
or turn off the switching module within a preset duration starting from a time instant when an acquired current of the switching module is less than or equal to a preset value, upon determining the current change trend of the switching module as the descending trend after the inverter circuit is subjected to the pulse blocking.
Gao teaches using preset delay times and current zero-crossing detection to determine turn-off timing (¶0019, ¶0029, ¶0046). The concept of a “preset duration” is reflected in the delay compensation logic used to ensure precise control.
Gao does not explicitly disclose:
The term “pulse blocking” or the specific mechanism of “disabling a drive pulse for each switching transistor in the inverter circuit.” While fault detection and inverter disconnection are taught, the internal control logic for disabling drive pulses is not described in detail.
The use of a “first preset current” that is greater than or equal to a “safe current.” Gao implies threshold-based control but does not define or compare against a “safe current” value.
The logic of turning off the switching module “within a preset duration starting from a time instant when an acquired current of the switching module is less than or equal to a preset value.” Gao teaches delay-based control but does not tie it directly to a current threshold event.
However, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement pulse blocking by disabling drive pulses to each switching transistor in response to a short circuit fault, as a standard safety practice in inverter systems to prevent damage and ensure rapid shutdown.
Further, it would have been obvious to incorporate threshold-based current comparison and descending trend analysis to improve the precision and reliability of switching module shutdown, especially in grid-connected systems where impulse currents and contact adhesion pose risks.
Finally, implementing a preset duration for shutdown after detecting a descending current trend would have been motivated by the desire to ensure safe timing, reduce switching losses, and avoid premature or delayed disconnection, as taught by Gao’s zero-crossing and delay compensation logic.
Re Claim 2; Gao discloses a controller configured to monitor output currents of switching modules and determine turn-off timing based on current behavior (¶0016, ¶0028, ¶0044–¶0046).
wherein for determining the current change trend of the switching module as the descending trend, the controller is configured to: continuously acquire a plurality of currents of the switching module; and determine the current change trend of the switching module as the descending trend in response to the plurality of currents of the switching module in the descending trend.
Gao teaches that the controller includes a current detection subunit configured to detect zero-crossing moments of current in each phase (¶0044), and a turn-off control subunit configured to determine when to turn off the switch based on the detected current behavior (¶0045–¶0046). While Gao does not use the phrase “continuously acquire a plurality of currents,” it teaches monitoring current over time and using that data to determine trends, including descending behavior.
Gao does not explicitly disclose:
The phrase “continuously acquire a plurality of currents,” nor does it specify the sampling rate or method of acquisition.
A formal trend analysis algorithm or logic that evaluates multiple current samples to confirm a descending trend.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement continuous current acquisition and trend analysis to improve the accuracy and reliability of switching decisions. In grid-connected inverter systems, impulse currents and contact adhesion risks are mitigated by precise timing based on current behavior. Continuous sampling enables better detection of descending trends, which supports safe and timely shutdown of switching modules.
Re Claim 3; Gao discloses a controller configured to monitor output currents of switching modules and determine turn-off timing based on current behavior, including zero-crossing detection and delay compensation (¶0018–¶0019, ¶0028–¶0029, ¶0044–¶0046).
wherein the preset value is zero, and the preset duration is a first duration for which a current of the switching module is zero; Gao teaches that switching modules are turned off at the zero-crossing moment of the current in each phase (¶0018, ¶0028, ¶0045), which corresponds to a current value of zero. The duration for which the current remains zero is implicitly used to time the turn-off signal.
the preset value is a current corresponding to a first time instant, the first time instant is a periodic time instant determined by subtracting a first delay duration from a time instant when a current in a periodic current curve corresponding to the switching module decreases to zero, and the first delay duration comprises a duration from a time instant when a turn-off signal is sent to the switching module to a time instant when the switching module is actually turned off, wherein the preset duration is a first duration for which a current of the switching module is zero; Gao teaches that the controller compensates for turn-off delay by adjusting the timing of the turn-off signal relative to the zero-crossing moment (¶0019, ¶0029, ¶0046). This implies that the controller calculates a time instant by subtracting a delay duration from the zero-crossing point, and uses that to issue the turn-off signal.
or the preset value is a current corresponding to a second time instant, the second time instant is a periodic time instant determined by subtracting a second delay duration from a time instant when a current in a periodic current curve corresponding to the switching module decreases to zero, and the second delay duration comprises a duration from a time instant when a turn-off signal is sent to the switching module to a time instant when the switching module is actually turned off, and a power-resistant duration from a time instant corresponding to a maximum impulse current withstood by the switching module to a time instant when the current in a descending portion of the periodic current curve decreases to zero; and the preset duration is a sum of a first duration for which a current of the switching module is zero and two times of the power-resistant duration. Gao teaches that the controller accounts for turn-off delay and current shock protection by adjusting the timing of the turn-off signal (¶0019, ¶0029, ¶0046). While Gao does not explicitly disclose a “power-resistant duration,” the concept of avoiding contact adhesion and ensuring reliable turn-off under high current conditions implies that the system is designed to withstand impulse currents and compensate accordingly.
Gao does not explicitly disclose:
The term “power-resistant duration” or the specific logic of summing two times that duration with the zero-current duration.
A formal definition of “preset value” as a current corresponding to a calculated time instant.
The exact mathematical structure of the timing logic involving subtraction of delay durations and summation of impulse current durations.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement timing logic that compensates for turn-off delays and impulse current risks, as part of a robust switching control strategy. Gao’s teachings on zero-crossing detection, delay compensation, and current-based control provide a clear motivation to refine the timing of turn-off signals. Incorporating additional safety margins, such as power-resistant durations, would be a predictable enhancement to improve reliability and protect switching modules from damage due to transient currents.
Re Claim 4; Gao discloses a controller configured to determine turn-off timing of switching modules based on current zero-crossing and delay compensation (¶0018–¶0019, ¶0028–¶0029, ¶0044–¶0046).
Gao teaches that the controller compensates for turn-off delay by adjusting the timing of the turn-off signal relative to the zero-crossing point of the current (¶0019, ¶0029, ¶0046). Gao also teaches that the controller considers the delay time and the zero-crossing moment to ensure precise control of the switching module turn-off.
Although Gao does not disclose the exact mathematical equation recited in Claim 4, it teaches the underlying principle of calculating a turn-off moment based on waveform characteristics (e.g., sinusoidal current and voltage), delay durations, and phase relationships. The use of trigonometric functions and frequency-based timing is implicit in the zero-crossing and delay compensation logic.
Gao does not explicitly disclose:
The inverter according to claim 3, wherein the first duration is calculated by the following equation: T = π + π⁄6 / 2π * 1⁄f + ΔT wherein, ΔT represents a first time length from a time instant when the current of the switching module decreases to zero to a nearest time instant when a voltage of the switching module is zero on condition that the current descending trend of the switching module is the descending trend, ΔT = (2π - arcsin(V⁄2U)) / 2π * 1⁄f, 3π⁄2 < arcsin(V⁄2U) < 2π, U represents a rated voltage of phase power corresponding to the switching module, V represents a voltage of the phase power corresponding to the switching module, and f represents a frequency of the phase power corresponding to the switching module.
The explicit use of rated voltage (U), instantaneous voltage (V), and frequency (f) in a formulaic structure for calculating turn-off duration.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement mathematical timing equations using sinusoidal voltage and current waveforms to precisely calculate switching module turn-off durations. Gao’s teachings on zero-crossing detection and delay compensation provide a clear motivation to refine timing logic using waveform analysis. Incorporating trigonometric functions and frequency-based calculations would be a predictable enhancement to improve timing accuracy, reduce switching losses, and avoid contact adhesion during turn-off.
Re Claim 5; Gao discloses a controller configured to monitor output currents of switching modules and determine current change trends based on sampled current values (¶0016, ¶0028, ¶0044–¶0046).
wherein for the determining the current change trend of the switching module at the current time instant, the controller is configured to: determine the current change trend of the switching module at the current time instant based on a current of the switching module acquired before the current time instant; and/or acquire a second current of the switching module if a specified duration expires; and determine the current change trend of the switching module based on a relationship between the first current and the second current.
Gao teaches that the controller includes a current detection subunit that detects the zero-crossing moment of the current in each phase (¶0044), and a turn-off control subunit that determines when to turn off the switch based on the current behavior (¶0045–¶0046). While Gao does not explicitly describe acquiring a “second current” after a specified duration, it teaches evaluating current behavior over time to determine trends, which implies comparing current values at different time instants.
Gao does not explicitly disclose:
The acquisition of a “second current” after a specified duration.
The use of a defined “first current” and “second current” pair to determine the trend.
A formal time-based sampling interval or trend evaluation algorithm.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement a trend detection method based on comparing current values at two time instants, especially in systems where current behavior determines safe switching. Gao’s teachings on current monitoring and zero-crossing detection provide a clear motivation to refine trend analysis using time-separated current samples. This approach improves the reliability of switching decisions and ensures that shutdown occurs only when the current is verifiably decreasing, thereby protecting the switching module from damage due to premature or delayed turn-off.
Re Claim 6; Gao discloses a controller configured to monitor output currents of switching modules and determine turn-off timing based on current behavior, including zero-crossing detection and delay compensation (¶0016, ¶0018–¶0019, ¶0028–¶0029, ¶0044–¶0046).
wherein after determining whether a first current of a switching module of the at least one switching module at a current time instant is less than or equal to a first preset current, the inverter is further configured to: monitor the current of the switching module in response to the first current of the switching module being greater than the first preset current; and turn off the switching module upon monitoring that the current of the switching module decreases to be less than or equal to the first preset current.
Gao teaches that the controller monitors the output current of each phase and determines when to turn off the switching module based on current behavior (¶0016, ¶0028, ¶0044–¶0046). Specifically, Gao discloses that switching modules are turned off at the zero-crossing moment of the current, which implies that the controller continues monitoring the current until it reaches a threshold (e.g., zero or near-zero) before initiating turn-off.
Although Gao does not explicitly disclose a conditional monitoring step based on the current being greater than a preset value, the system’s behavior implies that current is continuously monitored and switching decisions are made when the current falls below a safe or predefined threshold and a conditional monitoring step triggered only when the first current exceeds the preset current.
A formal logic structure that waits for the current to drop below the preset value before initiating turn-off.
Therefore, it would have been obvious to one of ordinary skill in the art to implement a control strategy wherein the inverter continues monitoring the current after detecting that it exceeds a preset threshold, and then turns off the switching module once the current drops below that threshold, as part of a safe and reliable switching protocol and also to implement conditional current monitoring and threshold-based turn-off logic to improve switching safety and reliability. Gao’s teachings on current monitoring and zero-crossing detection provide a clear motivation to refine control logic so that switching modules are turned off only when the current is sufficiently low, thereby minimizing contact adhesion, impulse current damage, and premature switching.
Re Claim 7; Gao discloses a controller configured to monitor output currents of switching modules and determine turn-off timing based on current behavior, including zero-crossing detection and delay compensation (¶0016, ¶0018–¶0019, ¶0028–¶0029, ¶0044–¶0046).
Wherein the controller is further configured to:acquire a second preset current of the switching module, wherein the second preset current is less than the safe current of the switching module;monitor the current of the switching module in response to the first current of the switching module being greater than the first preset current; andturn off the switching module upon monitoring that the current of the switching module decreases to be less than or equal to the second preset current.
Gao teaches that the controller monitors current in each phase and determines switching behavior based on current thresholds and zero-crossing detection (¶0016, ¶0028, ¶0044–¶0046). Gao teaches that switching modules are turned off when the current reaches zero or a low value, and that turn-off timing is adjusted to avoid contact adhesion and impulse current damage (¶0018, ¶0029, ¶0045–¶0046).
Gao’s control logic implies that the system monitors current until it reaches a safe level before initiating turn-off. The concept of using a lower threshold (second preset current) to trigger shutdown is consistent with Huawei’s emphasis on minimizing current shock and ensuring reliable switching.
Gao does not explicitly disclose:
The use of a “second preset current” that is numerically less than the safe current.
A formal logic structure that monitors current specifically in response to the first current being greater than the first preset current.
A conditional turn-off based on the second preset current threshold.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement a dual-threshold current monitoring strategy to improve switching safety and precision. Gao teachings on current monitoring, zero-crossing detection, and impulse current mitigation provide a clear motivation to introduce a lower preset current threshold to trigger shutdown. This approach enhances protection of switching modules, reduces wear, and aligns with Gao’s goal of minimizing current shock during disconnection.
Re Claim 8; Gao discloses a power converter comprising switching modules that include multiple relays per phase (K1–K6 in Fig. 3), and a controller configured to control these relays during grid connection and disconnection (¶0012, ¶0024, ¶0032–¶0037).
wherein for each of the at least one switching module, the switching module comprises at least two relay switches, and a control terminal of each of the at least two relay switches is connected to the controller, wherein for the turning off the switching module, the controller is configured to: turn off one of the at least two relay switches in the switching module.
Gao teaches that each phase includes two stages of switching devices (first-stage and second-stage), each comprising N switches (¶0012). These switches are shown as relays K1–K6 in Fig. 3, with K1/K3/K5 and K2/K4/K6 representing separate control paths. The controller is connected to these relays and manages their activation and deactivation (¶0024, ¶0032–¶0037).
While Gao does not explicitly state that each switching module comprises “at least two relay switches,” the structure of the system implies that each phase includes two relays—one in each stage—controlled independently. Gao also teaches that the controller can selectively turn off relays one by one based on current behavior (¶0016, ¶0028–¶0029, ¶0045–¶0046), which implies the ability to turn off individual relays within a switching module.
Gao does not explicitly disclose:
That the switching module is a unified structure containing “at least two relay switches.”
That the controller is configured to turn off “one of” the relay switches in the switching module, as opposed to both or all relays in sequence.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement a switching module with multiple relays per phase to provide redundancy, staged control, and fault isolation. Gao’s teachings on dual-stage switching and independent relay control provide a clear motivation to selectively deactivate one relay within a module to reduce current shock, extend relay life, or isolate faults. This approach enhances system reliability and aligns with Gao’s emphasis on minimizing impulse currents and improving control granularity.
Re Claim 9; Gao discloses a power converter comprising an inverter circuit, at least one switching module, and a controller (¶0012, ¶0024, Fig. 3), and further teaches a method for controlling the switching devices during grid connection and disconnection (¶0024–¶0026, ¶0030, ¶0040–¶0047).
A method for turning off an inverter, wherein the inverter comprises: an inverter circuit, at least one switching module and a controller; an input end of the inverter circuit is configured to connect a direct-current (DC) source, an output end of each phase of the inverter circuit is connected to a corresponding switching module of the at least one switching module, and an output end of the at least one switching module is configured to connect a power grid; and the method comprises:
Gao teaches a power converter system in which the inverter circuit is connected to a DC source (¶0012), each phase of the inverter is connected to a switching module (¶0012, Fig. 3), and the output of the switching module connects to the power grid (¶0012, ¶0024). The method for controlling the inverter includes staged switching and current-based shutdown (¶0024–¶0026, ¶0028–¶0029, ¶0040–¶0047).
performing pulse blocking on the inverter circuit in response to a short circuit of a negative electrode of the DC source to ground, wherein the pulse blocking comprises disabling a drive pulse for each switching transistor in the inverter circuit;
Gao teaches that the controller detects short circuit faults at the input or output of the inverter and disconnects the inverter from the grid (¶0030, ¶0047). While the term “pulse blocking” is not used, the act of disconnecting the inverter implies disabling drive signals to the switching transistors to prevent further conduction.
determining whether a first current of a switching module of the at least one switching module at a current time instant is less than or equal to a first preset current after the inverter circuit is subjected to the pulse blocking, wherein the first preset current is greater than or equal to a safe current of the switching module;
Gao teaches monitoring output current of each phase and determining switching behavior based on current thresholds and zero-crossing detection (¶0016, ¶0028, ¶0044–¶0046). Although the term “first preset current” is not explicitly used, the logic of comparing current values to safe thresholds is inherent in the control strategy.
determining a current change trend of the switching module at the current time instant in response to the first current of the switching module being less than or equal to the first preset current; and
Gao teaches determining current change trends based on zero-crossing detection and delay compensation (¶0018–¶0019, ¶0028–¶0029, ¶0044–¶0046).
turning off the switching module in response to the current change trend being a descending trend; or turning off the switching module within a preset duration starting from a time instant when an acquired current of the switching module is less than or equal to a preset value, upon determining the current change trend of the switching module as the descending trend after the inverter circuit is subjected to the pulse blocking.
Gao teaches turning off switching modules based on current zero-crossing and preset delay times (¶0019, ¶0029, ¶0046). The concept of a “preset duration” is reflected in the delay compensation logic used to ensure precise and safe switching.
Gao does not explicitly disclose:
The term “pulse blocking” or the specific mechanism of “disabling a drive pulse for each switching transistor.”
The formal use of “first preset current” and “safe current” as defined thresholds.
The exact logic of initiating a preset duration from the moment the current falls below a preset value.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement a method for turning off an inverter using staged switching, current monitoring, and delay-compensated shutdown. Gao’s teachings provide a clear framework for such a method. Incorporating pulse blocking via disabling drive pulses, using threshold-based current comparisons, and initiating turn-off based on descending current trends or preset durations would be predictable enhancements aimed at improving safety, reliability, and protection of switching components during fault conditions.
Re Claim 10; Gao discloses a photovoltaic power generation system comprising a photovoltaic array and a power converter (¶0023).
A photovoltaic system, comprising: a photovoltaic string; and an inverter, wherein the photovoltaic string is connected to an input end of the inverter, and is configured to supply direct-current (DC) power to the inverter; an output end of the inverter is configured to connect a power grid, convert DC power into alternating-current (AC) power and transmit the AC power to the power grid, and the inverter is the inverter according to claim 1.
Gao teaches a photovoltaic power generation system in which a photovoltaic array (photovoltaic string) is connected to the input of a power converter (inverter), and the inverter converts DC power into AC power and transmits it to the power grid (¶0023, ¶0012, Fig. 3). The inverter includes all the structural and functional features recited in Claim 1, including the inverter circuit, switching modules, and controller (¶0012, ¶0024, ¶0030–¶0047).
Therefore, Gao fully teaches a photovoltaic system comprising a photovoltaic string and an inverter as recited in Claim 10.
Gao does not explicitly use the term “photovoltaic string,” but it uses the synonymous term “photovoltaic array” (¶0023), which is commonly understood in the art to refer to a series-connected group of photovoltaic modules.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement the inverter of Claim 1 within a photovoltaic system, as taught by Gao. The integration of a photovoltaic string (or array) with an inverter that converts DC to AC and connects to the grid is a standard architecture in photovoltaic power systems. Gao’s disclosure directly supports this configuration, and no inventive step would be required to substitute the term “photovoltaic string” for “photovoltaic array,” as both refer to standard DC sources in solar energy systems.
Response to Arguments
Applicant's arguments filed 02/06/2026 have been fully considered but they are not persuasive.
Applicant argues that Gao (EP 4 199 293 A1) fails to teach or suggest the following two limitations of claim 1:
(a)
“determine a current change trend of the switching module… and turn off the switching module in response to the current change trend being a descending trend.”
Applicant asserts that Gao only teaches turning off at a zero‑crossing moment, not determining whether the current is descending. Applicant cites Gao ¶¶[0018], [0019], [0028], [0029], and [0044]–[0046] and argues that these paragraphs merely describe delay compensation to hit the zero‑crossing more precisely, not trend‑based logic.
(b)
“turn off the switching module within a preset duration starting from a time instant when an acquired current… is less than or equal to a preset value…”
Applicant argues that Gao does not teach turning off within a duration or window after the current falls below a threshold. Instead, Gao allegedly teaches only a single instant (the zero‑crossing moment). Applicant further argues that the present invention uniquely handles uncontrollable hardware delays and relay inconsistencies, whereas Gao only handles a known, fixed delay.
Applicant concludes that Gao is “totally silent” on determining current trend or selecting a turn‑off moment within a safe duration, and therefore cannot render the claims obvious.
However, the examiner respectfully disagrees.
1. Gao inherently teaches determining whether the current is descending, even if not using the applicant’s terminology.
Although Gao does not use the literal phrase “current change trend,” Gao’s control method requires the controller to determine whether the current is moving toward zero (descending) before issuing the turn‑off command.
Gao ¶[0018] explicitly states:
“At a zero-crossing moment of a current of each phase, a relay corresponding to the phase may be controlled to be turned off…”
This is not a static measurement. To detect a zero‑crossing moment, the controller must:
Monitor the current waveform over time,
Detect that the current is approaching zero,
Distinguish between before and after the crossing,
Issue the turn‑off signal in advance so that the physical opening occurs while the current is descending.
This necessarily requires the controller to understand the direction of change—i.e., whether the current is descending toward zero or rising away from zero.
Gao ¶[0028] reinforces this:
“This avoids contact adhesion… caused by an excessively large current.”
To avoid large current, the controller must ensure the current is moving toward zero, not away from it. This is functionally identical to determining a descending trend.
Gao ¶[0044]–[0046] further confirm trend‑based behavior:
“Detect a zero-crossing moment of a current…” “Based on a preset turn-off delay time and the zero-crossing moment… output a turn-off signal…”
This requires the controller to predict when the current will reach zero, which is only possible by analyzing the slope (trend) of the current waveform.
Thus, while Gao does not use the applicant’s exact words, Gao does teach the underlying concept: turning off only when the current is decreasing toward a safe region.
2. Gao teaches issuing the turn‑off command within a time window, not at a single instant.
Applicant argues that Gao only teaches turning off at a single zero‑crossing moment. However, Gao explicitly introduces a time period t₁ and a delay td, which together form a preset duration in which the controller must issue the turn‑off signal.
Gao ¶[0019] states:
“If there is a time period t1 before the zero-crossing moment… the delay td needs to be deducted from t1.”
This means:
There is a window (t₁ – td) during which the controller must act.
The controller issues the turn‑off signal before the zero crossing so that the actual physical opening occurs at the desired current condition.
This is directly analogous to the applicant’s “preset duration starting from a time instant when the current ≤ preset value.”
Gao’s window is functionally equivalent to applicant’s duration.
Both systems:
Identify a safe current region,
Define a time window relative to that region,
Issue the turn‑off command within that window,
Ensure the physical opening occurs under safe current.
Thus, Gao already teaches the concept of a duration‑based turn‑off window.
3. Gao explicitly addresses relay delay and variability.
Applicant argues that Gao does not address “uncontrollable hardware delays” or “relay inconsistency.”
However, Gao directly acknowledges and compensates for relay delay:
Gao ¶[0019] states:
“As the relay has a turn-off delay during actual control… the delay td needs to be deducted…”
Gao ¶[0046] similarly states:
“Based on a preset turn-off delay time… output a turn-off signal…”
This shows that Gao:
Recognizes that the relay does not open when the signal is issued,
Measures or presets a delay,
Adjusts the control timing accordingly.
This is the same problem the applicant describes relay delay and inconsistency and Gao already provides a solution framework.
4. Applicant’s “trend + duration” logic is a predictable refinement of Gao’s teachings.
Gao already teaches:
Monitoring current,
Detecting zero crossing,
Using a time window (t₁ – td),
Avoiding large current at turn‑off,
Compensating for relay delay.
Given this, it would have been obvious to a person of ordinary skill to:
Add an explicit check that the current is descending, and
Generalize the zero‑crossing window into a preset duration tied to a safe current threshold.
These are incremental refinements, not departures from Gao’s control philosophy.
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 DANIEL KESSIE whose telephone number is (571)272-4449. The examiner can normally be reached Monday-Friday 8am-5pmEst.
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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.
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/DANIEL KESSIE/
03/26/2026
Primary Examiner, Art Unit 2836
Prosecution Insights