Relink US LLC (“Relink”) sued Tesla, Inc. (“Tesla”), alleging infringement of U.S. Patent No. 9,793,755 (“the ’755 patent”). On April 28, 2025, the case was transferred from the Western District of Texas to the Northern District of California. Relink US LLC v. Tesla, Inc., Case No. 1:25-cv-3365, Dkt. No. 21, ¶ 1 (N.D. Cal. Dec. 4, 2023) (previously Case No. 1:23-cv-1093 in the Western District of Texas).
According to the First Amended Complaint, Relink’s managing member and the named inventor of the ’755 patent, Paul Garrity, is a “prolific inventor having been a named inventor on over 40 patents.” Relink, Dkt. No. 21 at ¶ 2. The First Amended Complaint further alleges that “Tesla is familiar with Mr. Garrity’s innovations, as Tesla is the assignee of numerous patented inventions created by Mr. Garrity concerning various solar and energy technologies.” Id.
Tesla’s petition for inter partes review of the ’755 patent was not instituted. Tesla, Inc. v. Relink US LLC, IPR2024-00389, Paper 9 (PTAB July 16, 2024) (Decision denying institution of inter partes review).
The ’755 patent, titled “Uninterruptible Power Supply and Method for Managing Power Flow in a Grid-Tied Photovoltaic System,” purportedly solves problems associated with conventional grid-tied photovoltaic inverters. According to the ’755 patent, a typical prior art configuration of micro-inverters uses a voltage-frequency relay 180 to monitor the voltage and frequency of the utility grid 100, and may be used to disconnect the micro-inverters 110, 120, 130 (e.g., during repair or maintenance). The ’755 patent, 5:4-29. According to the ’755 patent, in the prior art configuration, the micro-inverters 110, 120, 130 “only function as current sources. That is, when the utility grid 100 is not producing power, it is not possible to operate the house load 150 from the prior art micro-inverters.” Id. at 5:33-36.
The ’755 patent, Fig. 1 (annotated).
The purported invention of the ’755 patent includes an Uninterruptible Power Supply (“UPS”) 300 with a DC port 306 which is connectable to a battery, an AC port 305 which is connectable to the utility grid 100, and a load port 304 which can be connected to both an AC load 150 and the micro-inverters 110, 120, 130. The ’755 patent, 6:38-45.
The ’755 patent, Fig. 4 (annotated).
According to the ’755 patent, the UPS 300 may further comprise a switch 303, a controller 301, and a power converter 302. The switch 303 may be used to disconnect the AC port 305 from the power converter 302 and from the load port 304. The ’755 patent, 6:45-54.
The ’755 patent, Fig. 3 (annotated).
The ’755 patent discloses that the power converter 302 has several functions and may provide bi-directional power flow. Specifically, the power converter 302 may operate as a current-source converter and charge the battery on the DC port 306 by drawing a sinusoidal AC current from the AC port 305 and converting the AC current to DC current. The power converter 302 may operate as a current-source inverter for peak load regulation by using power from the DC port 306 to inject current into the AC port 305. And the power converter 302 may operate as a voltage-source converter by producing a sinusoidal voltage having a frequency that may be used to limit, and thus regulate, power produced by the micro-inverters 110,120,130.
Claim 1 of the ’755 patent recites:
An uninterruptible power supply comprising:
a bi-directional converter configured to operate as an alternating current voltage source;
a direct current power port configured to be coupled to a battery;
a first alternating current power port coupled to the bi-directional converter and configured to be coupled to a current-source inverter, wherein the current-source inverter is configured to adjust an output power as a function of a frequency of the alternating current voltage source; and
a controller configured to regulate a power flow of the current-source inverter by adjusting a frequency of the alternating current voltage source.
The ’755 patent, 9:47-60.
Relink identifies, as Accused Instrumentalities, “a Tesla Inverter, including those of the Powerwall (fka Powerwall 2) and Powerwall+ systems.” Relink, Dkt. No. 21 at ¶ 12.
For example, Relink accuses the Powerwall as being a bi-directional converter, as recited in claim 1, because the Powerwall is configured to “provide stored energy from a battery to home appliances during power outage,” and “convert energy from the grid to charge a battery.” Relink, Dkt. No. 21-2 (Infringement Chart), 7. Relink also accuses the Powerwall of having a direct current power port, as recited in claim 1, because the Powerwall has a “port that is used to provide power to and/or from the Powerwall battery” and as being a direct current power port “because the battery stores DC power.” Id. at 15.
Relink, Dkt. No. 21-2, 7.
Relink accuses the Powerwall of having a current-source inverter configured to adjust output power, as recited in claim 1, because the Powerwall has a solar inverter “configured to trip and discontinue or adjust its output power in response to the system frequency.” Relink, Dkt. No. 21-2, 24; id. at 31. Relink also accused the Powerwall of being a controller as recited in claim 1, because the Powerwall “is configured to raise system frequency to reduce or discontinue solar inverter power output based upon the frequencies of an AC voltage source.” Id. at 38.
Relink, Dkt. No. 21-2 at 13.