DCT
1:23-cv-00315
NexGen Control Systems LLC v. Infineon Tech AG
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: NexGen Control Systems, LLC (Delaware)
- Defendant: Infineon Technologies AG (Germany) and Infineon Technologies Americas Corporation (Delaware)
- Plaintiff’s Counsel: Berger & Hipskind LLP; Bayard, P.A.
- Case Identification: 1:23-cv-00315, D. Del., 03/22/2023
- Venue Allegations: Venue is asserted based on Infineon Technologies Americas Corp. being a Delaware corporation and Infineon Technologies AG being a foreign entity subject to personal jurisdiction in the district.
- Core Dispute: Plaintiff alleges that Defendant’s iMotion series of motor controller products infringes a patent related to methods for improving the efficiency of electric motor inverters by actively managing inverter loss.
- Technical Context: The technology concerns advanced power control systems for permanent-magnet synchronous motors, which are critical components in applications like electric vehicles and industrial automation, where efficiency and thermal management are paramount.
- Key Procedural History: The complaint alleges that Defendants had pre-suit knowledge of the patent-in-suit due to a parallel patent infringement litigation in China involving a Chinese counterpart patent. After this U.S. complaint was filed, the USPTO issued an Ex Parte Reexamination Certificate for the patent-in-suit which cancelled several claims, including independent claim 1, the only claim specifically identified in the complaint's infringement allegations. This cancellation raises a threshold question regarding the viability of the asserted infringement count.
Case Timeline
| Date | Event |
|---|---|
| 2007-10-29 | '855 Patent Priority Date |
| 2012-10-02 | '855 Patent Issue Date |
| 2019-03-01 | Earliest Cited Documentation for Accused Product (Product Brief) |
| 2021-12-31 | Alleged Date of Pre-Suit Knowledge via Chinese Litigation |
| 2023-03-22 | Complaint Filing Date |
| 2025-01-06 | '855 Patent Reexamination Certificate Issue Date (Cancelling Claim 1) |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,278,855 - Controller of Motor Preventing an Increase in Inverter Loss, Issued Oct. 2, 2012
The Invention Explained
- Problem Addressed: The patent describes a problem in high-power motor controllers, such as those for electric vehicles. Using high-withstand-voltage switching elements in the motor's inverter results in significant energy loss (as heat), requiring large, heavy, and expensive cooling systems. This problem is exacerbated when the motor operates at high speeds, which can cause "excessively large" inverter loss and risk thermal failure of the components (’855 Patent, col. 1:55 - col. 2:11, col. 2:60-67).
- The Patented Solution: The invention proposes a "smarter" motor controller that actively works to prevent this excessive inverter loss. The controller includes a "current-command generating unit" that, under specific "predetermined conditions" where inverter loss is expected to spike (e.g., when the motor is running at high speed and the inverter is already outputting its maximum voltage), adjusts the current command sent to the motor. This adjustment is specifically designed to "maintain or decrease a loss of the inverter," thereby avoiding the high-loss operating modes that conventional controllers might enter (’855 Patent, Abstract; col. 13:48-58). The controller prioritizes keeping the inverter within its thermal limits, even if it means slightly deviating from the absolute maximum torque or efficiency for the motor itself under those specific conditions.
- Technical Importance: This control strategy allows for the use of smaller, lighter, and less expensive cooling systems by intelligently avoiding brief but potentially damaging spikes in heat generation within the power electronics, a key design consideration for compact and cost-sensitive applications like electric vehicles (’855 Patent, col. 2:65-67; col. 3:1-6).
Key Claims at a Glance
- The complaint asserts infringement of "at least claim 1" (Compl. ¶52). As noted, this claim was subsequently cancelled during reexamination.
- Independent Claim 1 (as originally issued) required:
- A controller of a motor comprising:
- a voltage-command generating unit that generates a pulse-width modulation signal to control a switching element provided in an inverter...
- a current-command generating unit that generates and outputs a current command to cause the alternating-current motor to generate torque based on an input torque command, wherein
- the current-command generating unit is configured to output the current-command that is calculated based on a relationship between the torque command and a state quantity of the alternating-current motor,
- to maintain a terminal voltage of the alternating-current motor to a maximum value that can be generated under the direct-current power source, and
- to output a current command adjusted to maintain or decrease a loss of the inverter under a predetermined condition in which the loss of the inverter increases or estimated to increase.
- The complaint does not explicitly reserve the right to assert dependent claims.
III. The Accused Instrumentality
Product Identification
- The accused instrumentalities are the "Infineon iMotion IMM100 Series and IMC100 Series products," which are identified as electric motor controllers (Compl. ¶23).
Functionality and Market Context
- The complaint alleges these products are integrated motor controllers containing a processor core, on-chip hardware, and firmware to manage AC motors (Compl. ¶25). They are described as implementing "Complex FOC [Field Oriented Control] control algorithms" to control fan, pump, and compressor applications (Compl. ¶25).
- Functionally, the products allegedly include a three-phase inverter circuit, a gate driver to generate PWM signals for the inverter, and a control engine that receives inputs (like torque commands) and calculates outputs (like current commands) to regulate the motor's speed and torque (Compl. ¶¶26, 31, 36-38). A diagram from Infineon's documentation shows the accused product's application block diagram, illustrating the processor core, gate driver, and three-phase inverter (Compl. ¶28).
- The complaint alleges these products are commercially significant and are sold to businesses and individuals throughout the United States (Compl. ¶50).
IV. Analysis of Infringement Allegations
'855 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a voltage-command generating unit that generates a pulse-width modulation signal to control a switching element provided in an inverter, to the inverter connected to a direct-current power source and outputting a three-phase alternating current... | The products allegedly include a "Gate Driver" and "iMOTION™ MCE2.0" core that generates a PWM signal to control the switching elements (FETs or CoolMOS) of a three-phase inverter, which is connected to a DC power source. | ¶¶26, 30, 32, 35 | col. 11:10-18 |
| a current-command generating unit that generates and outputs a current command to cause the alternating-current motor to generate torque based on an input torque command... | The products are alleged to contain a "current-command generating unit" or "current control" module that receives an input torque command and generates a current command to be sent to the motor to produce the desired torque. | ¶¶36, 37, 42, 45 | col. 11:18-24 |
| the current-command generating unit is configured to output the current-command that is calculated based on a relationship between the torque command and a state quantity of the alternating-current motor... | The accused products' control engine allegedly calculates the output current command based on inputs including the torque command and motor state quantities like feedback current and speed. A diagram shows these inputs to the control logic. | ¶¶40, 41, 47 | col. 18:28-35 |
| to maintain a terminal voltage of the alternating-current motor to a maximum value that can be generated under the direct-current power source... | The products allegedly maintain the motor's terminal voltage at the maximum possible value under the DC power source to ensure maximum efficiency. The complaint cites documentation stating the controller "adjusts the Id current to maintain the motor voltage magnitude within the bus voltage limit." | ¶¶41, 48 | col. 18:35-39 |
| and to output a current command adjusted to maintain or decrease a loss of the inverter under a predetermined condition in which the loss of the inverter increases or estimated to increase. | The products are alleged to adjust the current command to reduce the load on the inverter and prevent overheating when inverter loss is expected to increase. An annotated diagram is presented to show a "Current Command Unit Which Adjusts For Inverter Loss." | ¶¶43, 46, 48, 49 | col. 18:40-45 |
Identified Points of Contention
- Scope Questions: A central question, had claim 1 remained valid, would be the interpretation of "predetermined condition". The complaint alleges that conditions like "overcurrent, overheating, or other factors" trigger the claimed function (Compl. ¶43). The court would need to determine if this broad interpretation is supported by the patent, which provides more specific examples related to high-speed operation at maximum voltage (’855 Patent, col. 13:48-58).
- Technical Questions: The infringement theory hinges on whether the accused products' standard Field Oriented Control (FOC) and thermal management features perform the specific loss-avoidance strategy recited in the claim. A key question for the court would be whether the accused products' adjustment of current is merely an inherent result of any power management, or if it is a specific, purpose-driven function to "maintain or decrease a loss of the inverter" under the claimed "predetermined condition," as the patent appears to require. The complaint's visual evidence, such as the annotated diagram in paragraph 49, attempts to map general control blocks to this specific claimed function.
V. Key Claim Terms for Construction
The Term: "a predetermined condition in which the loss of the inverter increases or estimated to increase"
Context and Importance: This term is the trigger for the core inventive concept. Its scope determines when the special loss-avoidance control must be active. A broad definition would capture more of the accused product's standard operating modes, while a narrow definition tied to the specific high-frequency scenarios described in the patent would make infringement more difficult to prove.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language itself is general, not limiting the "condition" to any specific cause. The specification mentions that in an electric vehicle, there are situations where a user may operate the vehicle for a long time in a state where inverter loss is high, suggesting the condition is tied to sustained, high-loss operation generally (’855 Patent, col. 12:62-67).
- Evidence for a Narrower Interpretation: The specification provides a very specific example of the "predetermined condition": when a torque command is reduced while the inverter is already operating in a "one-pulse mode" (i.e., at its maximum output voltage) (’855 Patent, col. 13:48-58; col. 18:7-12). This suggests the condition is not just any increase in loss, but one that occurs in a specific, high-stress region of the motor's operating envelope where conventional controllers would switch to a higher-loss pulse mode.
The Term: "a current command adjusted to maintain or decrease a loss of the inverter"
Context and Importance: This term defines the "solution" part of the invention. Whether the accused products perform this "adjustment" will be a central factual dispute. Practitioners may focus on whether the adjustment must be the primary purpose of the control logic at that moment, or if any adjustment that has the effect of reducing loss suffices.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language does not explicitly state the adjustment's sole purpose. Any control logic that results in a current command that leads to lower inverter loss than an alternative command could arguably be "adjusted to...decrease a loss."
- Evidence for a Narrower Interpretation: The patent's background and detailed description frame the invention as an alternative to a specific, problematic action: switching to a "synchronous three-pulse mode" which dramatically increases inverter loss (’855 Patent, col. 12:51-61). The patented solution is to not do that, and instead adjust the current command while remaining in a "one-pulse mode" to avoid the loss spike (’855 Patent, col. 14:45-58). This context suggests the "adjustment" is a specific control choice made in lieu of another, higher-loss choice, not just a general efficiency tweak.
VI. Other Allegations
- Indirect Infringement: The complaint alleges inducement of infringement under 35 U.S.C. § 271(b), asserting that Infineon provides documentation, user manuals, and training that instruct and encourage customers to use the accused products in a manner that infringes the ’855 patent (Compl. ¶¶56-57). It also pleads contributory infringement under § 271(c), alleging the products are a material part of the invention, not a staple article of commerce, and are especially made for infringing uses (Compl. ¶58).
- Willful Infringement: Willfulness is alleged based on pre-suit knowledge of the ’855 patent since "at least December 31, 2021," purportedly from the service of a complaint in a Chinese litigation on an alleged Chinese affiliate involving the patent's counterpart (Compl. ¶54). The complaint also asserts post-suit knowledge from the filing of the instant lawsuit (Compl. ¶55).
VII. Analyst’s Conclusion: Key Questions for the Case
Threshold Viability: The primary and dispositive question for the case is the viability of the complaint itself. With independent claim 1—the only claim specifically alleged to be infringed—having been cancelled by the USPTO during a post-filing reexamination, the infringement count as pleaded appears to lack a valid legal basis. The court will first need to address whether the plaintiff can amend its complaint to assert one of the surviving claims.
Claim Scope (if the case proceeds): Should the plaintiff be permitted to amend its complaint to assert a surviving claim (e.g., confirmed claim 2), a central issue will be one of definitional scope. Can the phrase "predetermined condition" be construed broadly to cover general thermal management, or is it limited to the specific high-frequency, max-voltage operating scenarios detailed in the patent's preferred embodiments?
Operational Mismatch (if the case proceeds): A key evidentiary question will be one of functional operation. Does the accused iMotion controller's standard Field Oriented Control (FOC) perform the specific, unconventional loss-avoidance strategy required by the patent—namely, prioritizing inverter loss reduction over maximum torque by altering the current vector along a voltage limit curve—or is there a fundamental mismatch in the technical means used to achieve efficiency?