DC household appliance with a switching circuit
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Solution Overview
Problem
Current switching circuits for DC household appliances lack efficiency and reliability, particularly when attempting to replace corresponding AC switching circuits, due to issues with power-off switching and galvanic decoupling in DC systems.
Innovation Solution
A DC switching circuit utilizing semiconductor-based switching elements, such as MOS FETs, with a control unit and DC/DC power converters for safe and efficient power-off switching, allowing for seamless transformation between DC and AC variants by replacing the DC power supply and switching circuit with their AC counterparts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a DC switching circuit is designed for DC household appliances, then the appliance can be directly powered by DC voltage with improved efficiency, but the switching circuit lacks reliability compared to AC switching circuits
Solution Approach 1:
The patent designs a DC switching circuit that can be used in DC household appliances while maintaining compatibility with AC appliance architectures. The circuit incorporates universal components and design patterns that allow it to function reliably in DC environments while preserving the ability to be adapted to AC systems, thus achieving both energy efficiency and reliability.
Solution Approach 2:
The patent replaces traditional mechanical switching mechanisms with semiconductor-based switching elements optimized for DC operation. This substitution eliminates the reliability issues associated with mechanical wear and contact arcing in DC systems, while maintaining the energy efficiency benefits of direct DC power conversion.
2Adaptability or versatility
If a DC switching circuit is designed to replace AC switching circuits in a one-to-one manner, then component compatibility is improved, but the switching performance and reliability deteriorate
Solution Approach 1:
The DC switching circuit is designed with universal mounting interfaces, control signal compatibility, and standardized connection points that enable one-to-one replacement of AC switching circuits. At the same time, the internal circuit topology and switching elements are specifically optimized for DC operation, ensuring reliable performance in DC environments.
Solution Approach 2:
The patent modifies key electrical parameters of the switching circuit including voltage ratings, current handling capabilities, and switching frequencies to optimize for DC operation. These parameter changes maintain physical and interface compatibility with AC circuit replacements while ensuring reliable DC-specific performance characteristics.
3Loss of energy
If power-off switching is implemented in DC systems, then energy saving is improved, but galvanic decoupling becomes more difficult compared to AC systems
Solution Approach 1:
The patent replaces traditional mechanical relay-based power-off switching with solid-state semiconductor switching elements that provide galvanic decoupling through their inherent electrical characteristics. This substitution simplifies the decoupling mechanism while enabling effective power-off switching for energy conservation in DC systems.
Solution Approach 2:
The patent introduces intermediate circuit elements such as isolation barriers and decoupling capacitors that facilitate galvanic separation between the DC power source and the appliance circuitry. These intermediary components enable clean power-off switching and energy saving while managing the complexity of galvanic decoupling through standardized interface designs.
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
Enables efficient and reliable operation of DC household appliances, ensuring safe power-off switching and galvanic isolation, facilitating a one-to-one replacement with AC switching circuits, thus providing a cost-effective and efficient solution for both DC and AC variants.
Implementation Method 1
at least one DC switching circuit (220, 241, 242, 251, 252) comprising a semiconductor-based switching element (220) which is configured to galvanically interrupt the first DC supply line (251) or the second DC supply line (252) in reaction to a control signal
Data Source
Figure 1a~1c
Figure 2a
Figure 2b
AI summary
A household appliance (100) is described which comprises a DC power supply configured to provide a DC supply voltage between a first DC supply line (241, 251) and a second DC supply line (242, 252) from an external DC supply, which is external to the household appliance (100). Furthermore, the appliance (100) comprises an electrical component (103) which is configured to be operated by the DC supply voltage. The appliance (100) further comprises at least one DC switching circuit (200) comprising a semiconductor-based switching element (220) which is configured to galvanically interrupt the first DC supply line (241, 251) or the second DC supply line (242, 252) in reaction to a control signal (233).