Rotating Electric Machine Driver Simul-Off Abnormality Detection
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Solution Overview
Problem
Conventional rotating electric machine drivers cannot detect open failures and other faults that disable the connection of switching elements in the inverter, which can lead to incorrect detection of phase currents and unintended behavior of the machine.
Innovation Solution
A rotating electric machine driver with an inverter section, electric current detector, controller section, and abnormality detector that generates high-side and low-side instruction signals to switch upper and lower arm elements, and includes a signal amplifier and protection section to prevent false detection of phase currents by detecting simultaneous ON or OFF abnormalities in the instruction signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional current detection methods using shunt resistors are used, then the electric current can be detected, but open failures and faults disabling switching element connections cannot be detected
Solution Approach 1:
The patent segments the instruction signal into high-side and low-side signal components, and further divides the detection into multiple determination stages (simultaneous OFF detection, simultaneous ON detection). This segmentation allows comprehensive fault detection without requiring a completely different detection architecture, resolving the contradiction between detection capability and system complexity.
Solution Approach 2:
The patent performs preliminary detection of instruction signal abnormalities before they cause actual switching element failures. By detecting simultaneous OFF or simultaneous ON states in the instruction signals, the system can identify potential faults early, improving reliability without adding complex post-failure analysis systems.
2Measurement precision
If the simul-OFF abnormality determination time is set longer, then detection accuracy improves, but response time increases
Solution Approach 1:
The patent optimizes the simul-OFF abnormality determination time as a critical parameter, setting it to balance detection accuracy and response time. By carefully selecting this time parameter, the system achieves sufficient detection precision while minimizing the time loss, resolving the contradiction between measurement precision and time efficiency.
3Reliability
If dual systems of circuits are provided for amplifying voltage, then fault detection capability is improved, but device complexity increases
Solution Approach 1:
The patent makes the instruction signal detection system multi-functional by using it for both normal switching control and abnormality detection. The same high-side and low-side instruction signals used for switching also serve as the basis for detecting simultaneous OFF or simultaneous ON abnormalities, eliminating the need for separate dual amplification systems and reducing overall device complexity while maintaining fault detection capability.
Data Source
AI summary
A rotating electric machine driver apparatus and an electric power steering apparatus using the same includes a controller section that obtains a detected current value and generates a high-side instruction signal and a low-side instruction signal to switch an upper arm element and a lower arm element based on the detected current value. An abnormality detector determines a simul-OFF abnormality which is an abnormality of a pair made up of the high-side and low-side instruction signals being simultaneously switched off based on a condition that switching off of the high-side instruction signal for the upper arm element and the low-side instruction signal for the lower arm element pair continues for at least a simul-OFF abnormality determination time. In such manner, the simul-OFF abnormality of the instruction signals is detected.