Fail-Safe Software Error Detection via Pulse Signal Frequency
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Solution Overview
Problem
Fail safe software in motor control devices for hybrid and electric vehicles is not effectively monitored for errors, leading to potential instability due to excessive motor torque caused by software defects or operational issues, which can result in malfunctioning of the driving motor.
Innovation Solution
An error detection method that generates a pulse signal based on the operation state of the fail safe software and controls the PWM signal of the inverter by determining if its frequency is within a reference range, thereby preventing excessive motor torque by determining the presence or absence of errors in the software.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fail safe software is embedded in the motor control device to improve system stability, then system stability is improved, but the complexity of the control system increases and the software may have undetected errors
Solution Approach 1:
The patent implements a feedback mechanism by generating a pulse signal from the fail-safe software operation state and monitoring its frequency. The monitoring unit detects whether the pulse signal frequency matches the expected frequency, providing feedback on the software's correct operation. This feedback loop enables error detection without requiring complex additional hardware, as it utilizes the existing software execution states to generate detectable pulse signals.
2Reliability
If fail safe software is added to the inverter to prevent motor malfunction, then motor operation reliability is improved, but the difficulty of detecting software errors increases
Solution Approach 1:
The patent introduces an intermediary mechanism - a pulse signal generation unit - that translates the internal software operation state into an external detectable pulse signal. This intermediary converts abstract software execution states into concrete electrical signals with measurable frequencies. The monitoring unit then detects errors by comparing the pulse signal frequency against expected values, making software error detection straightforward without directly analyzing complex software code or states.
Data Source
AI summary
Disclosed is an error detection method of fail safe software, the method including outputting a pulse signal according to an operation state of fail safe software monitoring a fail safe function of a motor control device; determining presence or absence of an error of the fail safe software using a frequency of the pulse signal; and controlling an output of the motor control device based on the presence or absence of the error of the fail safe software. Accordingly, even though whether the motor control device is in an abnormal state is not determined due to an error of the fail safe software, it is possible to prevent excessive motor torque from occurring.