Inverter Failure Detection via Dual Drive Mode Current Analysis
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Solution Overview
Problem
Existing methods for detecting failures in inverter circuits are complex and slow, leading to delayed detection and reduced motor drive control effectiveness, particularly in electric power steering systems where rapid failure detection is critical.
Innovation Solution
A motor control device with a dual drive mode system that uses current detection values to determine inverter system failures by switching control patterns between upper-side and lower-side arms of the inverter circuits, allowing for rapid detection of failures through threshold value assessments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If complex prior art methods are used for failure detection, then detection accuracy may be maintained, but detection time increases and system complexity increases
Solution Approach 1:
The patent extracts only the essential current detection function needed for failure detection, eliminating complex detection mechanisms. By using existing current detection units already present in the motor control system, the invention achieves rapid failure detection without adding complex detection hardware or algorithms.
Solution Approach 2:
The invention makes the existing current detection unit serve dual purposes: normal motor control current measurement and failure detection. By utilizing the self-service capability of the existing detection system, no additional detection devices are needed, reducing system complexity while enabling rapid failure detection.
2Measurement precision
If complex prior art methods are used for failure detection, then detection accuracy may be maintained, but the detection configuration becomes complex
Solution Approach 1:
The invention makes the current detection unit universal by enabling it to perform both normal motor control functions and failure detection functions. The same detection unit and current values are used for both purposes, eliminating the need for separate detection systems and simplifying the overall configuration while maintaining detection accuracy.
Solution Approach 2:
The patent merges the failure detection function with the existing motor control current detection system. By combining these functions into a single integrated approach using the same hardware and data, the invention reduces configuration complexity while preserving detection precision.
3Reliability
If drive control is interrupted completely when inverter failure occurs in one phase, then system safety is improved, but motor cannot rotate and driver burden increases in electric power steering
Solution Approach 1:
The invention dynamically adjusts the control strategy based on the detected failure type. When a phase failure is detected, the system automatically switches from normal three-phase control to two-phase control mode, enabling the motor to continue rotating with reduced performance. This dynamic adaptation maintains both safety and operability in electric power steering applications.
Solution Approach 2:
The system prepares backup control strategies in advance for potential phase failures. By pre-programming the ability to operate in two-phase mode and having the control algorithm ready to switch modes, the system cushions the impact of failure and maintains steering functionality without complete interruption.
Data Source
AI summary
An inverter system failure is detected on the basis of the currents of respective phases detected by a current detection unit when carrying out switching control in accordance with a first drive mode in which all switching elements on a lower-side arm are switched on and all switching elements on an upper-side arm are switched off, and the currents of respective phases detected by the current detection unit when carrying out switching control in accordance with a second drive mode in which all of the switching elements on the upper-side arm are switched on and all of the switching elements on the lower-side arm are switched off.