EV Inverter Gate Leakage Detection via Embedded Power Module Control
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Solution Overview
Problem
Inverters for electric vehicles face challenges in accurately detecting gate leakage in power device switches, particularly in high electromagnetic field environments, which can lead to premature failure of silicon carbide (SiC) devices due to inaccessible gate terminals and distorted PWM signals.
Innovation Solution
A point-of-use controller with an embedded gate leakage measurement circuit is integrated within the power module to detect gate leakage non-invasively, compensating for temperature and system level offset errors, and storing leakage data for precise monitoring during the device's lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If gate leakage detection is performed in high electromagnetic field environments, then detection capability is improved, but measurement precision deteriorates due to signal distortion
Solution Approach 1:
The patent introduces an intermediary measurement approach by detecting gate leakage through the gate driver circuit rather than directly at the gate terminal. The gate driver acts as a mediator that translates the inaccessible gate terminal status into measurable electrical parameters (gate drive current, voltage drops) that can be accurately measured even in high electromagnetic field environments, thus resolving the contradiction between detection capability and measurement precision
Solution Approach 2:
The patent replaces direct electrical measurement at the gate terminal with an indirect measurement system that uses the existing gate driver circuitry. Instead of mechanically accessing the gate terminal, the system substitutes a measurement method that utilizes electrical parameters already present in the gate driver, thereby maintaining measurement precision while enabling detection in challenging electromagnetic environments
2Reliability
If gate terminals are made inaccessible for safety reasons, then device reliability is improved, but detection precision deteriorates due to inability to directly measure gate leakage
Solution Approach 1:
The gate driver circuit serves as an intermediary that bridges the gap between the inaccessible gate terminal and the measurement system. By measuring parameters at the gate driver (such as gate drive current and voltage drops across series resistors), the system maintains device reliability through terminal inaccessibility while achieving precise gate leakage detection through the intermediary measurement points
Solution Approach 2:
The patent implements feedback mechanisms where the gate driver continuously monitors its own output parameters (gate drive current, voltage drops) and feeds this information back for analysis. This feedback loop enables precise inference of gate leakage status without requiring direct access to the gate terminal, thus maintaining both reliability and detection precision
3Device complexity
If point-of-use controller is integrated within power module, then device complexity is reduced, but manufacturing precision requirements increase due to embedded measurement circuit integration
Solution Approach 1:
The patent merges the gate leakage detection functionality with the existing gate driver circuit by integrating measurement circuits within the power module. The point-of-use controller combines multiple functions (gate driving, leakage detection, temperature monitoring) into a single integrated unit, reducing overall device complexity while the modular design standards ensure manufacturing precision is maintained through established integration processes
Data Source
AI summary
A system includes an inverter configured to convert DC power from a battery to AC power to drive a motor, wherein the inverter includes: one or more controllers configured to provide a test signal to control a gate leakage detection operation, and a power module including: a phase switch including one or more phase power switches, and a point-of-use controller configured to detect a gate leakage of the phase switch based on the test signal.