Rotary Machine Controller Shutoff Failure Diagnosis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing electric power steering apparatus requires a complex configuration to verify the shutoff function of switching devices in rotary machines, which complicates the detection process and increases the risk of failure determination.
Innovation Solution
A controller for rotary machines with an inverter and control circuit that includes current and voltage command calculation units, switching signal generation, and shutoff failure determination, allowing for forcible shutoff of high or low potential side switching devices to simplify the diagnosis of shutoff failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the switching devices are verified one by one using terminal voltages of the rotary machine, then the shutoff function can be checked, but the configuration becomes complex and requires additional detection means
Solution Approach 1:
The system uses its own operational characteristics (current flow patterns) to verify shutoff function, eliminating the need for external detection means. The control circuit monitors current during normal operation to determine if switching devices are properly shutting off, making the system self-diagnostic.
Solution Approach 2:
The invention extracts the verification process from a separate detection system and integrates it into the existing control circuitry by utilizing current measurement already performed for motor control, thereby removing the need for additional terminal voltage detection means.
2Reliability
If switching devices are verified one by one, then failure determination can be made, but the motor cannot rotate and the handle cannot rotate during the check
Solution Approach 1:
The verification is performed periodically during normal motor operation rather than requiring a separate check mode. The control circuit continuously monitors current patterns during regular motor control, allowing the motor to rotate and the handle to rotate while verification occurs in the background.
Solution Approach 2:
The motor continues to perform its useful function (rotation) while the verification process occurs simultaneously. The control circuit performs both motor control and shutoff verification continuously during normal operation, eliminating the need to stop the motor for checking.
3Measurement precision
If terminal voltages are measured to verify switching devices, then shutoff can be determined, but the configuration and detection process are complicated
Solution Approach 1:
The invention uses current measurement as an intermediary to infer switching device status. Instead of directly measuring terminal voltages to determine shutoff, the system measures current flow patterns during operation, which indirectly but reliably indicates whether switching devices are functioning properly.
Solution Approach 2:
The invention replaces the voltage measurement approach with a current measurement approach. By substituting the detection method from voltage-based to current-based, the system simplifies the detection process while maintaining verification accuracy, as current measurement is already integrated into the motor control system.
Data Source
AI summary
To provide a controller for a rotary machine which can simplify a configuration required for checking the shutoff function of the switching device, and an electric power steering apparatus therewith. A controller for a rotary machine performs a high potential side forcible shutoff which forcibly shuts off a high potential side switching device of a diagnosis object phase in a drive state where the winding current of the diagnosis object phase becomes positive, or a low potential side forcible shutoff which forcibly shuts off a low potential side switching device of the diagnosis object phase in a drive state where the winding current of the diagnosis object phase becomes negative; and determines failure of the device shutoff unit based on a detection value of current or voltage when performing the high potential side forcible shutoff or the low potential side forcible shutoff.