Motor Phase-Voltage Period Measurement for IGBT Path Fault Detection
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Solution Overview
Problem
Existing systems for electric motor control in vehicles lack comprehensive fault coverage diagnostics, particularly for IGBT control and feedback paths, leading to potential system failures during safe state operations, and are resource-intensive with high PCB real estate requirements.
Innovation Solution
A phase-voltage based motor period measurement system using differential capacitively coupled interfaces and ASICs for fault detection, which applies a commanded phase voltage to electric motor inputs, measures periods, and identifies faults by comparing them to a commanded frequency, providing comprehensive fault coverage without the need for high voltage isolation amplifiers or secondary microprocessors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If comprehensive fault coverage diagnostics are implemented for IGBT control and feedback paths, then system reliability is improved, but device complexity and resource consumption increase
Solution Approach 1:
The system performs self-diagnosis by injecting test patterns during initialization and automatically detecting faults in the IGBT control and feedback paths without requiring external testing equipment or complex diagnostic infrastructure
Solution Approach 2:
Fault detection is performed during the initialization phase before normal operation begins, allowing the system to identify and report faults proactively rather than reactively, improving reliability without adding operational complexity
2Measurement precision
If high voltage isolation amplifiers and secondary microprocessors are used for fault detection, then measurement precision is improved, but area of stationary object increases
Solution Approach 1:
The patent integrates multiple functions (fault detection, test pattern generation, and control logic) into a single integrated circuit, eliminating the need for separate high voltage isolation amplifiers and secondary microprocessors, thereby reducing PCB area while maintaining detection accuracy
Solution Approach 2:
The integrated circuit performs multiple functions including generating test patterns, measuring feedback signals, and detecting faults within a single device, replacing what would traditionally require multiple specialized components and reducing overall system footprint
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables fast and comprehensive fault detection and verification of the IGBT control and feedback path, reducing resource consumption and PCB area, while ensuring ASIL D functional safety requirements are met, and supports continuous operation by identifying faults before enabling torque.
Implementation Method 1
The first phase voltage input and the second phase voltage input may be connected to a first differential capacitively coupled interface of a first integrated circuit
Data Source
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AI summary
A method for phase-voltage based motor period measurement includes generating a commanded phase voltage and applying the commanded phase voltage to a first phase voltage input of an electric motor, a second phase voltage input of the electric motor, and a third phase voltage input of the electric motor. The method also includes measuring a first period of a phase voltage associated with the first phase voltage input and the second phase voltage input and comparing the first period of the phase voltage associated with the first phase voltage input and the second phase voltage input to a frequency of the commanded phase voltage. The method also includes, in response to a determination that the first period of the phase voltage associated with the first phase voltage input and the second phase voltage input is outside of a range of the frequency associated with the commanded phase voltage, identifying a fault associated with the first integrated circuit or signal path.