Motor Control Circuit Redundant Switch-Off Safety
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Solution Overview
Problem
Existing motor control systems lack a simple and fail-safe method for switching off motors in case of faults, relying on separate safety circuits which can be redundant and complex.
Innovation Solution
A method and device that utilize pulse-width-modulated switching signals divided into multiple independent control signals for a bridge circuit, allowing for safe motor shutdown by independently switching off functional channels through redundant switch-off signals, eliminating the need for separate safety circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate independent protective circuits are used for motor shutdown, then motor safety is improved, but device complexity increases
Solution Approach 1:
The patent merges the protective circuit functions into the existing pulse-width-modulated control channels. Instead of using separate independent protective circuits, the control unit utilizes the existing control signals to generate switch-off signals, thereby combining safety functions with the existing control structure and reducing overall device complexity while maintaining motor safety
Solution Approach 2:
The existing control channels are made multi-functional by enabling them to perform both normal motor control operations and protective shutdown functions. The control unit generates switch-off signals from the same control signals used for motor operation, allowing the control system to serve multiple purposes without requiring dedicated separate circuits
2Reliability
If redundant switch-off signals are used in independent switching channels, then fail-safe switching is improved, but control system complexity increases
Solution Approach 1:
The patent segments the control signals into multiple independent switching channels, with each channel capable of generating switch-off signals independently. This segmentation allows redundant protection paths without requiring a completely separate safety system, as each existing control channel is divided to provide both control and protective functions
Solution Approach 2:
The control system provides self-service by generating its own switch-off signals from the existing control signals. The control unit monitors its own control signals and automatically generates protective shutdown commands when faults are detected, eliminating the need for external separate safety circuits and reducing overall system complexity
Data Source
AI summary
A method controls a motor, especially for opening and closing a door. The motor is controlled by a pulse width-modulated switching signal that is divided into a specifiable number of pulse width-modulated control signals for actuating a bridge circuit to a corresponding number of functional channels. The functional channels are switched off independently from each other by at least one or more switch-off signals on at least one switching circuit of a number of independent switching circuits corresponding to the number of functional channels.