Obviousness

Under 35 U.S.C. § 103, an invention is considered obvious if the differences between the claimed invention and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art (PHOSITA). The analysis requires identifying: 1) the scope and content of the prior art, 2) the differences between the prior art and the claims at issue, 3) the level of ordinary skill in the pertinent art, and 4) any secondary considerations of obviousness.

For US Patent 11967857, the key inventive aspects, as outlined in the independent claims, revolve around a proactive and intelligent power source load control system. This system aims to prevent overloads and optimize efficiency by:

• Knowing power source parameters (e.g., maximum load handling).
• Sensing power source output and calculating available power.
• Knowing load parameters, including priority.
• Proactively determining if a desired load can be supported by available power before connection.
• Connecting or disconnecting loads based on this determination, priorities, and changing conditions.
• Utilizing load switches and/or load limit devices for control.

Identified Prior Art References:

The patent itself discusses two significant prior art examples:

1. Generac Nexus automatic transfer switch with load manager option (FIG. 3): This system is described as a prior art backup power system that starts a generator when grid power fails and transfers the load. It includes:

   • A generator and transfer switch controller (14) responsive to grid power.
   • Load managers (14a), which are contactors, to switch high-current loads on and off.
   • Monitoring of AC power frequency from the generator to detect overloads (e.g., frequency drops below 58 Hz).
   • Reactive load shedding: all low-priority (nonessential) loads are simultaneously disconnected after an overload occurs.
   • Sequential reconnection of loads based on priority, with a delay, and a mechanism to disconnect loads again if an overload recurs (described as "blindly switched on without knowing if it will again cause an overload").

2. U.S. Patent Application Publication 2010/0134073 (Tesla Motors, Inc.): This publication is incorporated by reference in US11967857 for its prior art teachings regarding battery charging control. It describes:

   • An elaborate manner in which battery charging current, temperature, and various other factors are controlled.
   • The ability to control the maximum load drawn from the power grid or generator by controlling charging current.
   • The Tesla High Power Connector (HPC) with a manual current selector switch that is set at installation to limit the maximum current the charger is allowed to draw "according to the capability of the circuit connection to the supply."

Obviousness Combination and Motivation:

A combination of the Generac Nexus automatic transfer switch with load manager and the teachings from U.S. Patent Application Publication 2010/0134073 (Tesla Motors) would render the claims of US11967857 obvious to a PHOSITA in the field of power systems and load control.

Motivation to Combine:

The patent itself highlights the critical shortcomings of the Generac system, stating, "Importantly this load shedding takes place after the overload happens." It further notes that "the overload, and possibly damage to the generator or its load, may have already happened by the time the overload is detected." Additionally, the Generac system's reconnection process is criticized as "blindly switched on without knowing if it will again cause an overload." These explicit critiques serve as a strong motivation for a PHOSITA to seek improvements to the Generac system's reactive and inefficient load management. The overarching goal would be to develop a more proactive, predictive, and intelligent load control system that prevents overloads rather than merely reacting to them.

The Tesla reference provides the very tools and concepts needed to address these shortcomings. It teaches the principle of:

• Proactive Load Limitation: The Tesla HPC's manual current selector switch demonstrates a mechanism to limit the maximum current a device can draw based on the supply circuit's capability, set at installation. This is a direct example of preventing an overload before it occurs or before full power is drawn.
• Intelligent Load Control: The Tesla publication describes controlling battery charging current based on various factors like temperature and charge state. This exemplifies dynamic, intelligent adjustment of a load's power demand.

How the Combination Leads to the Invention:

A PHOSITA, starting with the Generac system (which already provides a framework for backup power, transfer switching, and prioritized load management), and motivated to overcome its reactive nature, would look for ways to implement proactive load control.

1. From Reactive to Proactive Overload Prevention: Instead of waiting for the generator's frequency to drop (indicating an overload) before shedding loads, a PHOSITA would integrate the Tesla concept of "controlling the maximum load drawn from the power grid or generator". This would involve modifying the Generac controller (14) to:

   • More precisely "know parameters of the power source" (e.g., maximum wattage or current capability, rather than just implicitly knowing via frequency drop). The Tesla HPC's manual setting "according to the capability of the circuit connection to the supply" teaches this concept.
   • More precisely "sense output power" (beyond just frequency) to "calculate available power" in real-time. This is essential for effective current limiting.
   • Before "blindly switching on" a prioritized load, the controller would "determine if a desired load can be supported by the available power" by comparing the load's known parameters (which Generac already uses for prioritization) against the calculated available power.

2. Implementation of Load Limiting/Modulation: The Generac system uses contactors (load managers 14a) for simple on/off switching. The Tesla patent explicitly teaches "controlling charging current" to "control the maximum load drawn from the power grid or generator". Recognizing that some high-demand loads (like an oven or battery charger) could benefit from reducing power rather than complete disconnection, a PHOSITA would be motivated to replace or augment Generac's on/off contactors with load limit devices (like the patent's "load limit module 43" with "current control circuit 44") that can actively limit the power supplied to a load, as exemplified by the Tesla charger. The patent itself notes, "a nonessential load such as a vehicle battery charger turned off or limited to prevent any overload."

3. Continuous Optimization and Predictive Control: While Generac focuses on preventing damage via reactive shedding, the combination with Tesla's dynamic load control based on various factors (e.g., battery temperature/charge) would naturally lead to a system that continuously compares available power to required load and makes adjustments not only for overload prevention but also for "optimum output for improved efficiency." The patent discusses "monitoring and recording parameters e.g. the operation of various loads" to learn load characteristics, which would enable more sophisticated predictive and optimizing control, building on the basic dynamic control taught by Tesla.

Conclusion:

A PHOSITA, faced with the recognized drawbacks of the reactive load shedding in the Generac system, would find a clear motivation to incorporate the proactive load control and limiting principles taught by the Tesla publication. By combining the Generac system's architecture for backup power and prioritized load management with Tesla's methods for intelligently controlling and limiting the power drawn by specific loads, the PHOSITA would arrive at the proactive, intelligent load control system claimed in US11967857. This combination would directly address the problem of preventing overloads before they occur and provide a more efficient and reliable power management system.