Motor Controller Inverter Segmentation for ON-State Failure Identification
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Solution Overview
Problem
Existing motor controllers cannot identify which switching element has failed to turn ON while continuing motor operation, especially in systems with multiple switching elements like H bridge circuits, leading to motor shutdown during inverter ON-state failures.
Innovation Solution
A motor controller with two inverters, a magnetic sensor, failure detection unit, inverter driving section, signal examination unit, and failed element identification unit that continues driving the motor by stopping the faulty inverter and using the other inverter to identify the failed switching element based on special magnetic flux and electrical angle analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the motor controller stops the motor when an ON-state failure is detected to identify the failed phase, then the identification accuracy is improved, but the motor operation is interrupted and productivity is reduced
Solution Approach 1:
The patent divides the inverter system into two independent inverters (first inverter and second inverter), each capable of driving the motor separately. When an ON-state failure is detected in one inverter, the other inverter continues to operate, allowing the motor to keep running while the failed inverter is diagnosed. This segmentation enables simultaneous fault identification and continuous operation.
Solution Approach 2:
The patent introduces a magnetic sensor as an intermediary device to detect magnetic flux generated by the motor windings. By analyzing the magnetic flux waveform and its derivative, the system can identify the specific failed switching element without needing to stop the motor or rely on signals from the failed inverter itself. The magnetic sensor acts as a mediator that provides diagnostic information through a different physical pathway.
2Measurement precision
If the motor controller stops the motor to identify the failed switching element in an H bridge circuit, then the identification accuracy is improved, but the loss of time increases
Solution Approach 1:
The patent performs preliminary analysis of the magnetic flux waveform characteristics during normal operation to establish baseline patterns for each switching element. When a failure occurs, the system compares the current waveform against these pre-established patterns to rapidly identify the failed element. This preliminary preparation enables quick fault identification without requiring extended downtime for analysis.
Solution Approach 2:
The patent replaces the conventional approach of stopping the motor to diagnose failures with a non-intrusive magnetic field-based diagnostic method. By using a magnetic sensor to detect flux patterns and analyzing the derivative of the magnetic flux waveform, the system can identify failed switching elements while the motor continues to rotate, eliminating the need to halt mechanical operation for diagnosis.
3Measurement precision
If the motor controller uses the signal from the failed inverter to identify the failure location, then the identification accuracy is improved, but the device complexity increases when multiple switching elements are involved
Solution Approach 1:
The patent uses the magnetic sensor as an intermediary that provides a unified diagnostic signal source for all switching elements. Instead of analyzing multiple complex signals from different failed components, the system analyzes the magnetic flux waveform and its derivative, which inherently encodes information about which switching element failed. This intermediary approach simplifies the diagnostic process even when multiple switching elements are involved.
Solution Approach 2:
The patent transforms the diagnostic approach by changing from analyzing electrical signals directly from the inverter to analyzing magnetic flux parameters. By examining the magnetic flux waveform and particularly its derivative, the system can identify the specific failed switching element based on characteristic patterns. This parameter transformation simplifies the identification process regardless of the number of switching elements in the H bridge circuit.
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
Enables continuous motor operation by identifying and isolating the failed switching element without needing the signal from the faulty inverter, enhancing detection accuracy and preventing motor shutdown during ON-state failures.
Implementation Method 1
a magnetic sensor that detects a magnetic flux generated around the winding
Data Source
AI summary
An electronic control unit includes two inverters, a magnetic sensor, a failure detection unit, an inverter driving unit, a signal examination unit, and a failed element identification unit. The magnetic sensor detects a magnetic flux generated around a winding. The failure detection unit detects an ON-state failure of the inverter. When the ON-state failure is detected, the inverter driving unit stops driving the inverter to which the ON-state failure has been detected, and continues driving the other inverter. The signal examination unit examines a presence or absence of a special signal. When there is a signal appearing according to a special magnetic flux, the failed element identification unit identifies a failed switching element based on a motor electric angle generated by the signal.