Motor Drive Circuit Checks for Transistor and Relay Abnormalities
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional brushless DC motor drive devices face challenges in efficiently switching current direction based on rotor position, leading to potential abnormalities and inefficiencies in motor operation.
Innovation Solution
A motor drive device integrating half-bridges for U, V, and W phases with N-channel MOSFET transistors and shunt resistors for current detection, along with a control logic unit for check operations to identify and address abnormalities in transistors, relays, and power supply relays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional brushless DC motor drive devices switch current direction based on rotor position, then motor operation is achieved, but abnormalities and inefficiencies occur in motor operation
Solution Approach 1:
The control logic unit performs check operations before normal motor operation to detect abnormalities in advance. The system checks the on/off states of transistors and relays, and detects short circuits and open circuits in the motor, preventing abnormalities from occurring during operation. This preliminary detection approach ensures reliable motor operation by identifying and addressing issues before they cause harm.
2Reliability
If check operations are performed to detect abnormalities in transistors and relays, then reliability is improved, but check time increases
Solution Approach 1:
The check operations are segmented into different priority levels. The control logic unit performs high-priority checks first (such as checking power supply relays and transistors), then performs lower-priority checks. This segmentation allows the system to detect critical abnormalities quickly while still performing comprehensive checks, thereby reducing overall check time without sacrificing reliability.
Solution Approach 2:
The check operations are designed to be performed continuously or periodically during motor operation rather than requiring complete system shutdown. The control logic unit can perform checks while the motor is running, maintaining continuous useful action and minimizing interruption to motor operation, thus reducing time loss while ensuring reliable detection.
3Reliability
If comprehensive check operations are performed on all components, then reliability is improved, but device complexity increases
Solution Approach 1:
The control logic unit serves multiple functions: it controls the half-bridges for motor operation, performs check operations to detect abnormalities, and prioritizes checks based on importance. This multi-functionality consolidates what would otherwise require separate dedicated circuits into a single universal controller, reducing device complexity while maintaining comprehensive abnormality detection capability.
Data Source
AI summary
A motor drive device includes: a check performance unit configured to perform an abnormality check operation for at least one of an upper transistor, a lower transistor and a motor in a state where a second main electrode is pulled up or pulled down by bringing one of a second main electrode pull-down switch and a second main electrode pull-up switch into an on state; and a control circuit configured to control a combination of on/off states of the upper transistor, the lower transistor and a motor relay connected to the motor.