Failure Determination Device for Rotating Electrical Machines
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Solution Overview
Problem
Existing failure determination devices for vehicles with rotating electrical machines, particularly those controlled by one-pulse control, are unable to detect disconnections or poor contact in signal lines and conducting wires connected to the inverter, reducing the effectiveness of failure detection opportunities.
Innovation Solution
A failure determination device that acquires rotation angle, voltage phase, angular velocity, and direct-current voltage data to calculate current expectation values and determine signal line or wire failures based on these values, even when the inverter is controlled by one-pulse control, and also uses current target data for pulse width modulation control scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the inverter is controlled by one-pulse control, then the control method is simpler and energy efficiency is improved, but the ability to detect disconnection and poor contact in signal lines and conducting wires is lost
Solution Approach 1:
The system performs preliminary action by calculating the expectation value of current before actual current measurement occurs. This allows the failure determination device to have a reference value ready for comparison, enabling continuous monitoring even during one-pulse control periods when traditional Q-axis current commands are not generated. The expectation value serves as a predictive benchmark that maintains detection capability throughout all control cycles.
Solution Approach 2:
The invention introduces an intermediary mechanism by using the expectation value of current as a mediator between the control system and the failure detection system. Instead of directly relying on Q-axis current commands (which don't exist in one-pulse control), the system uses this calculated expectation value to bridge the gap and enable continuous failure detection. This intermediary allows the detection system to function independently of the specific control method being used.
2Device complexity
If the inverter is controlled by one-pulse control, then device complexity is reduced, but the frequency of failure determination opportunities decreases
Solution Approach 1:
The system ensures continuity of useful action by maintaining failure determination capability during one-pulse control periods. Instead of having detection opportunities only during PWM control, the invention calculates expectation values continuously and compares them with actual current measurements during one-pulse control, thereby extending the useful detection action to cover all operating conditions and maximizing detection frequency without increasing control complexity.
Solution Approach 2:
The failure determination system performs self-service by using readily available data (rotation angle, voltage phase, angular velocity, direct-current voltage, and actual current) to generate its own reference values for comparison. The system does not depend on external Q-axis current commands from the control system, allowing it to independently maintain detection functionality throughout all control cycles, thereby increasing determination frequency without adding system complexity.
3Ease of operation
If Q-axis current command is not generated in one-pulse control, then control process is simplified, but the accuracy of disconnection detection is reduced
Solution Approach 1:
The invention replaces the mechanical dependency on Q-axis current commands with a calculated expectation value system. Instead of requiring the control system to generate specific current commands for detection purposes, the invention substitutes this requirement with a mathematical model that calculates expected current based on fundamental motor parameters and operating conditions. This substitution maintains detection accuracy while preserving control simplicity.
Solution Approach 2:
The system changes parameters by shifting from using control-command-based current values (Q-axis commands) to using physically-based calculated expectation values. This parameter change allows the system to maintain high detection accuracy by relying on fundamental motor equations and actual measurements rather than control artifacts, thereby decoupling detection accuracy from control method complexity.
Data Source
AI summary
Provided is a failure determination device including: a storage medium that stores a command capable of being read by a computer; and a processor connected to the storage medium, wherein the processor executes the command capable of being read by the computer, to thereby acquire rotation angle data indicating a rotation angle of a rotor, voltage phase data indicating a phase of a voltage applied to a rotating electrical machine, angular velocity data indicating an angular velocity of the rotor, direct-current voltage data indicating a direct-current voltage supplied to an inverter that supplies electric power to the rotating electrical machine, and current data indicating a current supplied to the rotating electrical machine, generate current expectation value data indicating an expectation value of the current supplied to the rotating electrical machine using the rotation angle data, the voltage phase data, the angular velocity data, and the direct-current voltage data, and determine, in a case where the inverter is controlled by one-pulse control, whether at least one of a signal line connected to a switching element and a conducting wire for supplying electric power to the rotating electrical machine has failed on the basis of the current expectation value data and the current data.