Motor Switch Position Detection via Voltage Gradient Monitoring

The patent extracts the switching state detection function from the mechanical switch structure and relocates it to the control circuit domain. Instead of adding a physical contact to the switch, the solution uses the existing switch contacts to supply voltage to the control circuit, which then detects the switching state electronically through voltage monitoring. This separates the power switching function from the state detection function, eliminating the need for additional mechanical contacts.

The patent replaces the mechanical switching contact detection system with an electronic voltage monitoring system. The control circuit monitors the voltage at its input terminals to determine the switching state, substituting mechanical contact detection with electrical field-based detection. This eliminates mechanical complexity while maintaining detection reliability.

The control circuit continuously monitors its own input voltage and uses this feedback to determine the switching state. By comparing the monitored voltage against expected voltage profiles during different operating states, the control circuit can reliably distinguish between switch-on and switch-off conditions even during the transient period when regenerative voltage is present. This self-feedback mechanism eliminates ambiguity in switch state detection.

The patent employs dynamic voltage monitoring that adapts to the changing voltage conditions during motor shutdown. Instead of using a static detection threshold, the control circuit monitors the voltage profile over time and recognizes switching states based on the dynamic characteristics of voltage rise or fall. This dynamic approach allows reliable detection during the transient 1-2 second period when regenerative voltage is present.