Motor Controller Self-Diagnostic for Phase Sequence Verification
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Solution Overview
Problem
Existing methods for determining the correct electrical connections between a motor and a motor controller are inefficient and require the use of a test motor and oscilloscope, lacking a simplified diagnostic procedure that can be integrated into the motor controller or inverter.
Innovation Solution
A system utilizing a data processor to establish a monotonically varying test sequence of rotor angular positions through direct d-q-axis voltage commands, converting these into three-phase voltages for the motor, allowing self-rotation and determining connection correctness based on shaft speed signs without an oscilloscope or test motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods using test motor and oscilloscope are used to check phase sequence connection, then measurement precision can be achieved, but device complexity and ease of operation deteriorate due to requiring specialized equipment
Solution Approach 1:
The motor controller performs self-diagnosis by using its own internal resources (CPU, PWM generation module, current sensors) to evaluate connection correctness. The system injects test currents through its existing inverter circuitry and analyzes the resulting back-EMF signals without requiring external test equipment, making the system self-sufficient for diagnostic purposes
Solution Approach 2:
The invention extracts the diagnostic function from external specialized equipment (oscilloscope, test motor) and integrates it into the motor controller itself. By removing the dependency on external devices and implementing the measurement logic within the controller's existing hardware, the system achieves precise measurement without increasing overall device complexity
2Measurement precision
If traditional methods with test motor and oscilloscope are used, then proper phase sequence can be identified, but loss of time occurs due to complex setup and procedure
Solution Approach 1:
The motor controller performs connection verification as part of the startup sequence or maintenance routine before actual operation begins. By pre-checking connection correctness and identifying issues beforehand, the system avoids time-consuming troubleshooting during operational periods, ensuring quick diagnosis without compromising measurement accuracy
Solution Approach 2:
The diagnostic function is merged with the existing motor control operations. The same PWM generation module, current sensors, and processing units used for normal motor control are utilized for connection testing. This consolidation eliminates the need for separate testing procedures and equipment, reducing diagnostic time while maintaining measurement precision
3Ease of operation
If simplified diagnostic procedure without specialized equipment is implemented, then ease of operation improves, but measurement precision may deteriorate
Solution Approach 1:
The system implements a feedback mechanism where the motor controller analyzes the back-EMF signals generated during test current injection and compares them against expected patterns. The CPU processes the measured currents from existing sensors and determines connection correctness based on the phase relationships, providing accurate measurement through intelligent signal processing rather than complex hardware
Solution Approach 2:
The invention changes the operational parameters of the motor controller to enable diagnostic mode. By temporarily injecting specific test current patterns and measuring the resulting voltages during controlled rotor positions, the system achieves precise connection evaluation using standard components. The ability to vary operating parameters allows accurate measurement without requiring specialized test equipment
4Adaptability or versatility
If integrated diagnostic capability is added to motor controller, then adaptability improves, but device complexity increases
Solution Approach 1:
The motor controller is designed with multi-functionality, where the same hardware components (PWM generation module, current sensors, CPU) serve both normal motor control operations and diagnostic functions. By making the system universal and capable of performing multiple functions with the same resources, the invention adds adaptability without proportionally increasing device complexity
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
Facilitates efficient and quick evaluation of electrical connections between a motor and inverter, providing a simplified diagnostic process that can be performed in the field without specialized equipment, ensuring correct conductor connections.
Implementation Method 1
observing the back electromotive force (back-EMF) generated between pairs of the electrical terminals
Data Source
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AI summary
A pair of direct d-q-axis voltage commands is associated with a monotonically varying test sequence of test rotor angular positions (S300) to determine a correct rotational direction of a rotor of the motor in response to application of the pair of direct d-q-axis voltage commands to the motor. The rotor of the motor rotates (e.g., self spins in a diagnostic mode) in response to the applied direct d-q-axis voltage commands and applied monotonically varying test sequence of test rotor angular positions (S304). The primary positioning module or data processor determines that conductor connections between the inverter (e.g., motor controller) and the motor are correct if the calculated shaft speed sign is positive with respect to an applied monotonically varying test sequence of rotor angular positions that monotonically increases (S306).