Dual-Circuit Motor Control for Assist Torque During System Failure
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Solution Overview
Problem
Existing motor control devices face challenges in maintaining assist torque when one system fails, particularly due to difficulties in power supply control and sensor abnormalities, leading to concerns about motor performance and torque generation.
Innovation Solution
The control device incorporates a monitoring circuit to detect source voltage and communication abnormalities between two independent systems, allowing the external circuit to increase the operational amount of the remaining system, ensuring continuous torque generation and preventing excessive output through feedback control and assist correction values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If one system fails and only the other system operates, then the device complexity is reduced, but the assist torque required for the motor is not secured
Solution Approach 1:
The control device increases the operation amount of the remaining normal system in advance when a failure of one system is detected, rather than waiting for torque deficiency to occur. This preliminary adjustment ensures that the assist torque requirement is maintained continuously without interruption or performance degradation.
Solution Approach 2:
The operation amount (current command value) of the remaining normal system is dynamically changed based on the failure detection. When one system fails, the operation amount of the remaining system is increased according to the number of control systems, transforming the parameter to maintain the required total torque output.
2Reliability
If the operation amount of the remaining system is increased immediately upon detecting abnormality, then the assist torque is maintained, but excessive motor output may occur due to erroneous determination
Solution Approach 1:
An instruction from an external circuit is generated in advance when abnormality is detected, but the actual increase in operation amount is executed only after a predetermined period has elapsed. This preliminary preparation with delayed execution allows verification of the abnormality before committing to the parameter change, preventing erroneous adjustments.
Solution Approach 2:
The predetermined period acts as a cushioning buffer between abnormality detection and the actual increase in operation amount. This time delay allows the system to confirm the persistence and validity of the abnormality condition before making the operational change, preventing premature or erroneous responses to transient faults.
3Measurement precision
If communication monitoring is implemented to detect system failures, then the reliability of failure detection is improved, but the device complexity increases
Solution Approach 1:
A monitoring circuit is introduced as an intermediary component that specifically monitors communication between the first and second circuits. This dedicated monitoring mechanism provides accurate failure detection by detecting communication disruptions, isolating the complexity to a specialized function rather than distributing it throughout the entire control system.
Data Source
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AI summary
A control device (20) for a motor (10) including a first coil and a second coil which are insulated from each other is provided. The control device (20) includes a first circuit and a second circuit that switches a first process to a second process when the first circuit fails. The external circuit generates an instruction for performing a process of increasing an amount of operation which is calculated by one of the first circuit and the second circuit according to the number of control systems when the other of the first circuit and the second circuit fails.