Washer UI Powering via Free-Spinning Rotor and Passive Braking
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Solution Overview
Problem
There is a need to safely power an appliance user interface without external power sources like AC line power or batteries, particularly in scenarios where providing external power is inefficient or undesirable, such as in sales demonstrations, while ensuring user safety from moving components.
Innovation Solution
A method and system that utilize a motor's rotor power generation to charge a DC bus, with a motor control circuit applying passive braking by default to ensure safety conditions are met before disabling it, allowing the rotor to spin freely and power the user interface, which can then operate in a demonstration mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If external power supply (AC line power or battery) is provided for each appliance, then the user interface can be powered reliably, but it becomes inefficient and impossible to power multiple appliances in sales demonstrations
Solution Approach 1:
The appliance powers its own user interface by harvesting energy from its own motor rotor during normal operation. The motor controller converts a portion of the motor's generated energy to charge a DC bus, which then powers the user interface without requiring external power sources. This self-service approach eliminates the need for separate power supplies for each appliance.
2Ease of operation
If the rotor is allowed to spin freely to generate power for the user interface, then the user interface can operate without external power, but moving components pose safety risks to users
Solution Approach 1:
The system dynamically adjusts the rotor's braking state based on operational context. During normal washing operations, passive braking keeps the rotor stationary for safety. When entering demonstration mode with proper safety conditions met (door open, no wash cycle active), the controller disables passive braking to allow the rotor to spin freely and generate power for the user interface.
Solution Approach 2:
The system changes the motor controller's operational parameters between different modes. In normal operation, the controller maintains passive braking with specific duty cycle settings. In demonstration mode, it alters these parameters to disable passive braking, thereby changing the rotor's mechanical state from constrained to free-spinning to enable power generation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for safe and efficient powering of appliance user interfaces without external power, enhancing user safety by defaulting into an intrinsically safe state and enabling the appliance to simulate operation, thereby facilitating demonstrations without the risks associated with external power sources.
Implementation Method 1
receiving power generated by rotation of a rotor. The rotor is an element of a motor of the appliance
Implementation Method 2
The gate driver is configured to apply passive braking to the rotor upon initialization
Data Source
AI summary
Systems and methods for safely powering an appliance user interface without external power are provided. One exemplary method includes receiving power generated by rotation of a rotor. The method further includes monitoring for the presence of a safety condition and disabling passive braking of the rotor when the safety condition is present such that the user interface of an appliance is powered. An exemplary washing machine can include a basket and a motor which includes a rotor, the motor being configured to rotate the basket by rotating the rotor. The washing machine can further include a user interface and a motor control circuit configured to drive the motor. The motor control circuit can be further configured to receive power generated by rotation of the rotor, monitor for the presence of a safety condition, and disable passive braking of the rotor when the safety condition is present.