Motor Control Device Gate Buffer Abnormality Detection
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Solution Overview
Problem
Existing motor control devices cannot effectively detect abnormal states in three-state buffers, particularly when the switch control signal for conduction or blocking is not input, limiting the diagnosis functionality of safe stop circuits.
Innovation Solution
A motor control device that includes an inverter part, a gate driving circuit, a PWM generation circuit, and a control part with a test signal application mechanism to determine abnormality in gate buffers, featuring a diagnosis part that compares the switch control signal and the state of the gate buffer's output signal to identify discrepancies, and a logical product circuit for outputting functional state signals from multiple gate buffers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a three-state buffer is used for switching PWM signal conduction and blocking, then the gate driving circuit can be controlled, but abnormal states of the buffer cannot be detected when switch control signal is not input
Solution Approach 1:
The patent applies preliminary action by introducing a test signal input terminal that allows diagnostic test signals to be applied to the three-state buffer before normal operation. This enables the buffer's conduction and blocking functions to be verified in advance, and abnormal states to be detected even when no switch control signal is present. The test signal terminal is prepared in advance to facilitate diagnosis without requiring actual switch control signals.
2Reliability
If logical product of abnormal state signals from multiple gate buffers is used, then system-wide abnormality can be detected, but individual gate buffer abnormality cannot be identified
Solution Approach 1:
The patent applies segmentation by providing separate abnormal state output terminals for each gate buffer. Instead of combining all abnormal state signals into a single logical product output, each gate buffer has its own dedicated output terminal that indicates its specific abnormal state. This allows the system to detect both individual buffer abnormalities and overall system status, enabling precise identification of which specific buffer is malfunctioning while maintaining system-wide monitoring capability.
Data Source
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AI summary
To provide a motor control device that can determine occurrence of abnormality in a gate buffer. [Solution] A motor control device 1 configured to control a motor, including a gate driving circuit part 30 configured to drive the inverter part, a PWM control part 60 configured to generate a PWM signal applied to the gate driving circuit part 30, gate buffers 12, 22 disposed between the gate driving circuit part 30 and the PWM control part 60, and a device control part 50 configured to apply a test signal to the gate buffers 12, 22 to determine abnormality of the gate buffers 12, 22, the device control part 50 includes a comparative diagnosis part 80 configured to branch and input a switch control signal for conducting or blocking the PWM signal to the gate buffers 12, 22, and a pulse diagnosis part 70 configured to output the test signal to the gate buffer and to determine the abnormality of the gate buffers 12, 22 based on a state of the switch control signal and a state of a signal output from the gate buffers 12, 22.