Dynamic Safety Function Unit for Motor Control Adaptability
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Solution Overview
Problem
Existing power conversion systems lack dynamic safety function operations that can finely control motors in response to system abnormalities or diagnosis errors, limiting their ability to adapt and ensure safety effectively.
Innovation Solution
A power conversion device with a safety function unit that monitors motor states and executes pre-defined safety operations, including threshold-value-excess post-processes, to dynamically adjust motor control and enhance system safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple STO function is used to cut off torque when abnormalities occur, then the system structure remains simple and easy to operate, but the safety control capability is insufficient and cannot adapt to different abnormal conditions
Solution Approach 1:
The patent implements dynamic safety function operations that adapt to different abnormal conditions. The control unit selects from multiple pre-defined safety operations (coasting stop, dynamic brake stop, regenerative stop) based on the specific abnormality detected, making the safety response dynamic rather than static. This resolves the contradiction by enabling sophisticated safety control without requiring complex real-time decision logic during emergencies.
Solution Approach 2:
The patent pre-defines multiple safety function operations in advance, each suited for different abnormal conditions. The control unit stores and selects from these pre-configured operations when abnormalities occur, eliminating the need for complex real-time calculations during emergency situations. This preliminary preparation enables advanced safety control while maintaining operational simplicity.
2Reliability
If torque is immediately cut off by STO function when abnormalities occur, then the response time is fast, but the motor cannot be finely controlled according to system conditions
Solution Approach 1:
The patent implements dynamic selection of safety operations based on the specific abnormal condition detected. Different safety operations (coasting stop, dynamic brake stop, regenerative stop) provide different levels of control and response times appropriate to each condition. This dynamic approach achieves fine control precision without sacrificing response time, as each pre-defined operation is optimized for specific scenarios.
Solution Approach 2:
The patent changes operational parameters by selecting from multiple pre-defined safety operations with different characteristics. Each operation has distinct torque profiles, deceleration rates, and control strategies. By selecting the appropriate operation based on the abnormal condition, the system achieves precise control tailored to each situation without requiring complex real-time parameter adjustment.
3Adaptability or versatility
If multiple safety function operations are prepared in advance, then the system can adapt to different abnormal conditions, but the device complexity increases
Solution Approach 1:
The patent pre-defines multiple safety function operations with different control characteristics suitable for various abnormal conditions. These operations are configured in advance and stored in the control unit, enabling the system to adapt to different scenarios without requiring complex real-time decision logic. The control unit simply selects from the pre-configured options based on the detected abnormality type.
Solution Approach 2:
The control unit is designed with multi-functionality to handle multiple types of abnormalities using a single integrated safety function operation selection mechanism. Rather than requiring separate control systems for different abnormal conditions, the universal control unit selects from multiple pre-defined safety operations, achieving high adaptability without proportionally increasing system complexity.
Data Source
AI summary
A power conversion device includes a function of improving safety of a system by making a dynamical setting for a safety function operation at a time of detecting an abnormality in a system operation or a diagnosis error in accordance with a condition of the system at a time of the abnormality. A power conversion system includes a power conversion device main body configured to drive a motor and a safety function unit configured to execute a safety function. The safety function unit outputs a safety function operation instruction signal when receiving a safety request signal, and the power conversion device main body controls the motor by the safety function operation instruction signal. The safety function unit monitors a state of the motor, and, in a case where the state of the motor exceeds a predetermined range, executes a threshold-value-excess post-process by a safety function operation selected in advance.