Solid-State Motor Control Circuit for Direct AC Signal Interface
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Solution Overview
Problem
Current control circuits for devices like icemakers are inefficient, costly, and rely on complex mechanical parts, which limits their effectiveness and reliability.
Innovation Solution
A DC control circuit design that interfaces directly with AC signals using a motor driver or thyristor, pulsing the driver/thyristor at a specific frequency to convert AC to DC, eliminating the need for complex rectification and mechanical parts, thereby providing a cost-effective and efficient solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex mechanical parts are used in control circuits, then reliability may be improved through robust mechanical switching, but device complexity increases and energy efficiency deteriorates
Solution Approach 1:
The patent replaces mechanical switching components with solid-state electronic components. Specifically, mechanical relays and switches are substituted with transistors and integrated circuits that can perform switching functions electronically, eliminating moving parts while maintaining reliability and improving energy efficiency.
Solution Approach 2:
The patent extracts and removes complex mechanical parts from the control circuit design. By taking out the mechanical switching components and replacing them with simpler solid-state equivalents, the overall device complexity is reduced while preserving the essential control functions.
2Reliability
If complex rectification circuits are used to convert AC to DC, then conversion reliability is improved, but device complexity and energy loss increase
Solution Approach 1:
The patent extracts the unnecessary complex rectification stage from the AC to DC conversion process. By using a solid-state switch to directly control AC motor operation, the design eliminates the energy-lossy rectifier and filter components while maintaining reliable motor control through electronic switching.
Solution Approach 2:
The patent replaces the traditional mechanical/electrical rectification system with a solid-state electronic switching system. The transistor-based switch directly controls power delivery to the AC motor, eliminating the need for separate rectification and filtering circuits and reducing energy losses in the process.
3Adaptability or versatility
If traditional AC control circuits are used, then compatibility with AC signals is maintained, but energy efficiency and cost-effectiveness deteriorate
Solution Approach 1:
The patent substitutes traditional AC control circuitry with a solid-state transistor switching system. This solid-state implementation maintains full compatibility with AC signals and motors while dramatically reducing energy consumption through efficient electronic switching and elimination of unnecessary power conversion stages.
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
The solution achieves energy-efficient and reliable operation by converting AC to DC without complex rectification, reducing component stress and improving motor life, while allowing for adaptable and efficient icemaker operation with reduced energy consumption.
Implementation Method 1
A motor driver that has an input that receives an AC signal; a control circuit that pulses the driver at a first frequency to periodically turn the driver on, whereby allowing the AC signal to be converted to a DC signal suitable for driving a DC motor
Implementation Method 2
The motor driver is turned off when a portion of the AC signal crosses a threshold value so that the motor driver outputs a constant output when the portion the AC signal crosses the threshold value, thereby producing a DC output from the motor driver in response to applying the AC input to the motor driver
Data Source
AI summary
A circuit allows an energy efficient DC design to drop in to an AC application and interface directly with the AC signals in a cost effective manner. The circuit is implemented without any use of mechanically switched contacts. All switching of current is done through solid state devices. Positional feedback and speed of the motor is provided through an optically encoded output gear eliminating the need for mechanical position switches to determine motor rotational position.