PTAB

IPR2020-00966

SolarEdge Technologies Ltd v. SMA Solar Technology AG

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Power Generation System and Inverter for Feeding Power into a Three-Phase Grid
  • Brief Description: The ’630 patent discloses a relay arrangement for connecting a power generation system, such as a photovoltaic inverter, to a three-phase electrical grid. The system is designed to comply with safety standards requiring redundant, independently controlled switches on each conductor to disconnect from the grid and prevent "islanding."

3. Grounds for Unpatentability

Ground 1: Obviousness over Deng, Kunimoto, and Finder - Claims 1-6 and 11-19 are obvious over Deng in view of Kunimoto, and further in view of Finder.

  • Prior Art Relied Upon: Deng (Patent 6,239,997), Kunimoto (Japanese Patent Publication No. H11-69661), and Finder (a 2006 technical datasheet for "66 Series" relays).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Deng taught the foundational power generation system for connecting a supplemental power source to a three-phase grid, including an inverter and a single three-phase contactor (contactor 20) for grid disconnection. However, Deng's single contactor lacked the redundant switching required by safety standards. Kunimoto allegedly solved this deficiency by teaching a relay arrangement using three two-pole electromagnetic relays to provide two series-connected switches on each phase line, satisfying grid interconnection guidelines. Petitioner asserted that it would have been a simple substitution to replace Deng's contactor with Kunimoto's safer and more robust relay arrangement. To the extent Kunimoto did not explicitly disclose a control coil for its relays, Finder, a datasheet for commercially available two-pole relays, expressly taught a relay with a control coil operating two switching contacts.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Deng and Kunimoto to improve the safety and reliability of Deng's system and to comply with known industry safety standards (like the Japanese guideline cited in Kunimoto) that required redundant switches to prevent islanding. The motivation to add Finder's teachings was to implement the well-known, necessary component (a control coil) for operating the electromagnetic relays taught by Kunimoto.
    • Expectation of Success: A POSITA would have had a high expectation of success because the combination involved replacing one type of switching arrangement (a contactor) with another known, functionally similar, and improved switching arrangement (a multi-relay system) to perform the same function of grid disconnection. The result would have been a predictable improvement in system safety.

Ground 2: Obviousness over Deng, Korrek, and Finder - Claims 1-6 and 11-19 are obvious over Deng in view of Korrek, and further in view of Finder.

  • Prior Art Relied Upon: Deng (Patent 6,239,997), Korrek (Patent 8,363,371), and Finder (a 2006 technical datasheet).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground was presented as an alternative to the Kunimoto combination. Petitioner contended that, similar to Kunimoto, Korrek taught a safety switching device for a three-phase system using three electromechanical relays, with each relay's two switch contacts placed on different phase wires. This arrangement guaranteed a safe three-phase deactivation if a switch contact failed. Petitioner argued a POSITA would have replaced Deng's single contactor with Korrek's demonstrably safe three-phase relay arrangement. As in the first ground, Finder was cited for its explicit disclosure of a control coil, a standard component of the electromechanical relays described in Korrek.
    • Motivation to Combine: The primary motivation was to enhance the safety of Deng's system. Korrek explicitly teaches using its relay arrangement to guarantee safe deactivation of a three-phase system. A POSITA would have been motivated to incorporate this known safety solution into Deng's grid-tied inverter system. This modification would be a combination of known elements for a predictable result.
    • Expectation of Success: Success was expected due to the clear compatibility of the components. Both Deng and Korrek relate to three-phase power systems, and the combination involved substituting a known switching component with a known, safer alternative to achieve the predictable function of reliable grid disconnection.

  • Additional Grounds: Petitioner asserted numerous additional obviousness grounds by building upon the primary combinations. Grounds 5-8 challenged claims 6-9 and 19-22 by adding Nitsche (Application # 2008/0067877) to the Deng-Kunimoto-Finder and Deng-Korrek-Finder combinations. Nitsche was relied upon for its teachings of separate relay drivers for each relay and the use of a watchdog circuit to monitor the system controller. Grounds 9-12 challenged claims 9, 10, 22, and 23 by further adding Spreitzer (German Patent No. DE 100 29 828 C1) to the combinations including Nitsche. Spreitzer was cited for its teaching of using a short electrical test pulse to monitor the integrity of the relays without actually switching them.

4. Key Claim Construction Positions

  • “photovoltaic inverter” (claims 3, 15): Petitioner argued this term should be construed as “an inverter that converts the DC output of a photovoltaic solar panel into an AC source for a power grid,” consistent with the meaning advanced by the Patent Owner during prosecution.
  • “the relay arrangement is integrated into a housing” (claims 12, 16): Petitioner contended this phrase should be construed to mean the “relay arrangement is located inside a housing,” arguing that this reflects the ordinary meaning and context within the patent, as opposed to a more restrictive meaning like "merged" or "fused."

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that the IPR should not be denied discretionarily because the grounds presented were not cumulative to those considered during prosecution. The examiner's rejection was based on a Deng-Brooks combination that only sought to add series-connected switches, whereas Petitioner's grounds, relying on Kunimoto and Korrek, provided the specific three-relay, two-pole arrangement that was missing from the examiner's analysis. Petitioner also noted that key references like Korrek, Finder, and Spreitzer were never considered by the examiner.

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-23 of the ’630 patent as unpatentable.