Switchable Capacitor Module for AC to DC Adapter Size Reduction
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Solution Overview
Problem
Existing AC to DC adapters face inefficiencies due to voltage ripples and low peak voltages, leading to reduced efficiency in DC to DC converters, and are often bulky due to the need for high voltage and high capacitance bulk capacitors.
Innovation Solution
The use of selectively switchable capacitors with low voltage ratings and high capacitance, and a series string configuration to increase peak voltage, allowing for reduced physical size and improved efficiency by optimizing capacitance based on voltage thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If high voltage and high capacitance bulk capacitors are used to reduce voltage ripple, then voltage ripple is reduced, but physical size increases
Solution Approach 1:
The patent divides the bulk capacitor into multiple smaller capacitors (first capacitor and second capacitor) that can be selectively connected. This segmentation allows the system to achieve the required voltage ripple reduction without needing a single large high-voltage capacitor, thereby reducing overall physical size while maintaining effective capacitance when needed.
Solution Approach 2:
The patent implements dynamic switching between different capacitor configurations using switching units. The system dynamically connects or disconnects capacitors based on real-time voltage conditions, transitioning between series connection (for voltage multiplication) and parallel connection (for increased capacitance). This dynamic adaptation allows optimal performance across varying operating conditions without requiring permanently oversized components.
2Power
If high voltage bulk capacitors are used to support high peak voltages, then peak voltage is maintained, but physical size and cost increase
Solution Approach 1:
The patent employs dynamic switching between series and parallel capacitor configurations to adapt to varying voltage conditions. During high peak voltage periods, capacitors are connected in series to multiply voltage; during lower voltage periods, they switch to parallel configuration for maximum capacitance. This dynamic reconfiguration allows the system to maintain required peak voltage levels without permanently using oversized high-voltage capacitors.
Solution Approach 2:
The patent changes the electrical parameters (connection topology) of the capacitor system based on operating conditions. By switching between series and parallel configurations, the system dynamically alters equivalent capacitance and voltage rating parameters, allowing low-voltage-rated capacitors to effectively handle high peak voltages when needed, thereby avoiding the need for permanently oversized high-voltage capacitors.
3Volume of moving object
If low voltage rated capacitors are used, then physical size is reduced, but voltage ripple increases when voltage exceeds capacitor rating
Solution Approach 1:
The patent uses switching units that dynamically reconfigure capacitor connections based on voltage levels. When voltage remains within safe limits, capacitors operate independently or in parallel providing sufficient capacitance. When voltage approaches or exceeds individual capacitor ratings, the switching unit reconfigures them in series or selectively connects them, maintaining voltage ripple reduction capability while protecting capacitors from overvoltage damage. This dynamic adaptation allows small low-voltage capacitors to effectively handle varying voltage conditions.
Solution Approach 2:
The patent dynamically changes the effective voltage rating and capacitance parameters of the capacitor system by altering connection topology. Low-voltage-rated capacitors are connected in series during high voltage conditions to achieve the required voltage handling capability, while switching to parallel or selective connection during lower voltage conditions to maximize capacitance for voltage ripple reduction. This parameter transformation allows small capacitors to effectively replace large high-voltage capacitors.
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 reduces the physical size of AC to DC adapters while enhancing efficiency by minimizing voltage ripples and increasing peak voltages, resulting in a more compact and effective power conversion system.
Implementation Method 1
The switching unit couples the second capacitor in parallel with the first capacitor in the closed state
Implementation Method 2
an AC to DC adapter may selectively switch a series string of capacitors such that the DC to DC power converter of the AC to DC adapter receives a peak voltage that is greater than a peak voltage of the AC voltage received by the AC to DC adapter
Data Source
AI summary
In one example, a circuit includes a voltage rail, a reference node, a first capacitor, and a capacitor module. The first capacitor is coupled to the voltage rail and to the reference node. The capacitor module includes a second capacitor and a switching unit. The switching unit is configured to operate in a closed state and an open state. The switching unit couples the second capacitor in parallel with the first capacitor in the closed state. The switching unit decouples the second capacitor from the first capacitor in the open state.