Electric Power Steering Motor Control Failure Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electric power steering apparatuses require complex configurations to detect switching device cutoff failures, including terminal voltage detection, which complicates the process and is not effective in preventing output torque generation during startup.
Innovation Solution
A rotating-electric-machine control apparatus with a voltage applying unit, voltage command calculation unit, switching signal generation unit, switching device cutoff switching unit, and failure determination unit, which sets opposing torque directions for armature windings to suppress output torque before failure determination, simplifying the configuration and ensuring safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If terminal voltage detection is used to determine switching device cutoff function, then switching device failure can be detected, but the configuration becomes complex and startup process is prolonged
Solution Approach 1:
The patent extracts the terminal voltage detection function from the system and replaces it with current command/voltage command setting that generates opposing torques. This removes the need for complex voltage detection circuits while maintaining safety functionality.
Solution Approach 2:
The control unit uses its existing command generation capability to perform failure determination. By setting current commands that produce opposing torques, the system self-tests the switching device cutoff function without requiring external detection equipment.
2Reliability
If terminal voltage detection is implemented to prevent output torque generation, then safety is improved, but the startup time is prolonged
Solution Approach 1:
The patent applies preliminary action by setting opposing torque commands before formal failure determination is complete. The control unit proactively prevents output torque generation during the detection process, ensuring safety without waiting for detection to finish.
Solution Approach 2:
The system rushes through the failure determination process by using simplified current/voltage command setting instead of prolonged voltage detection. The opposing torque method quickly establishes safety conditions without the time-consuming voltage measurement process.
3Reliability
If switching device cutoff function is checked at startup, then latent failure can be detected, but additional detection units are required
Solution Approach 1:
The control unit performs multiple functions: it generates current commands for motor control, generates voltage commands, and performs failure determination. This multi-functionality eliminates the need for separate detection units while maintaining comprehensive safety monitoring.
Solution Approach 2:
The control unit self-tests its own switching device cutoff function by setting opposing torque commands and monitoring the system response. This self-service approach eliminates the need for external detection equipment.
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
The solution effectively suppresses output torque within mechanical loss, stabilizing the system and reducing user discomfort by ensuring accurate failure determination without complex terminal voltage detection.
Implementation Method 1
a voltage applying unit configured to convert a DC voltage from a DC power source into an AC voltage and apply the AC voltage to the first armature winding and the second armature winding
Data Source
Figure 1
Figure 2
Figure 3
AI summary
When a switching device cutoff failure determination unit determines a failure in a switching device cutoff switching unit, output torque produced based on the first armature winding and output torque produced based on the second armature winding are produced in such a way that the respective directions thereof are opposite to each other.