Motor Switching Circuit Fault Detection Before Startup
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Solution Overview
Problem
Conventional protection mechanisms for motor driven appliances are complex, costly, and prone to failure, failing to adequately protect motors and components from damage due to switching module malfunctions and short-circuiting.
Innovation Solution
A dual-switching module system with a control unit that separately controls two switching modules, using a detector circuit with resistors to measure divided voltages and determine if switching elements are short-circuited, ensuring the second switching module remains in a cut-off state until both modules are determined to be normal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional protection mechanisms are implemented, then motor protection capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the protection function with the existing driving circuit by using the same switching modules (first and second switching modules) that are already present in the motor control system. The control unit integrates both motor control and protection functions, eliminating the need for separate protection circuits. The first switching module controls motor operation while the second switching module handles protection functions, both managed by a single control unit that processes information from shared sensing circuits.
Solution Approach 2:
The control unit performs multiple functions: it controls the motor's operation through the first switching module, monitors system status through sensing circuits, detects faults through the second switching module, and manages overall system protection. This multi-functional approach eliminates dedicated separate protection circuits while maintaining comprehensive protection capabilities.
2Reliability
If redundant switching modules are added for protection, then system reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines protection functions with existing motor control components. The first switching module (already necessary for motor control) and second switching module (for protection) are integrated into a single control unit that shares power supply circuits, sensing circuits, and processing logic. This approach provides redundant protection capability without the full cost of completely separate protection systems.
Solution Approach 2:
The system uses its own existing switching modules and control unit to provide protection functions. The control unit monitors itself and the motor status using the same hardware resources already allocated for motor control, eliminating the need for entirely separate protection hardware and reducing manufacturing costs.
3Difficulty of detecting and measuring
If complex protection circuits are implemented, then fault detection capability is improved, but device complexity increases
Solution Approach 1:
The control unit continuously monitors the status of both switching modules and motor operation through sensing circuits. When a fault is detected (such as abnormal current, voltage deviations, or switching module failures), the control unit receives feedback signals and automatically responds by adjusting switching module states or shutting down the system to prevent damage. This feedback-based approach provides comprehensive fault detection without complex dedicated detection circuits.
Solution Approach 2:
The control unit acts as an intermediary that coordinates between the motor control functions and protection functions. It processes information from both the first switching module (motor control) and second switching module (protection), making decisions based on integrated information from shared sensing circuits. This intermediary role simplifies the overall system architecture while maintaining sophisticated fault detection and response capabilities.
Data Source
AI summary
A motor driven apparatus including a motor, a first switching module and a second switching module on a current path from one terminal of a battery to another terminal of the battery, and a MCU connected to the first and second switching module. The first and second switching module are connected in series to each other, while the first switching module is connected to the motor and adapted to drive the motor. The MCU is adapted to control the first second switching module separately. The MCU is further adapted to, upon its energization, attempt to control the second switching module to be in a cut-off state until the MCU determines that the first switching module is normal. The MCU attempts to detect failures of the switching elements in the first switching module before it enables operation of the motor.