Configurable Impedance Circuit for AC-DC Power Supplies
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Solution Overview
Problem
Conventional AC-to-DC power supplies require large and costly bulk capacitors to maintain voltage regulation for a wide range of AC input voltages, leading to bulky and expensive power supply units due to high capacitance and voltage rating demands.
Innovation Solution
A configurable impedance circuit that senses rectified voltage and adjusts the configuration of capacitors in series or parallel based on threshold voltages, reducing the total volume and cost of capacitors needed while maintaining hold-up time across varying AC input voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single bulk capacitor is used to cover the full AC input voltage range, then the power supply can operate across all voltage conditions, but the capacitor volume and cost increase significantly
Solution Approach 1:
The capacitor bank is divided into multiple individual capacitors that can be independently connected in series or parallel configurations. This segmentation allows the system to cover a wide voltage range using smaller, more efficient individual capacitor units rather than one large capacitor.
Solution Approach 2:
The capacitor configuration is made dynamic through switching circuits controlled by a microcontroller. The system automatically reconfigures the capacitor connections based on the detected AC input voltage level, transitioning between series and parallel arrangements to optimize performance for each voltage condition.
2Reliability
If high capacitance values are used to maintain hold-up time, then voltage regulation is maintained during AC failures, but the physical size and cost of the power supply increase
Solution Approach 1:
The system dynamically adjusts capacitor configuration based on operating conditions. During normal operation, capacitors are arranged to provide appropriate filtering. During AC failures, the switching circuit reconfigures the capacitors to maximize energy storage for hold-up time, all while maintaining a compact form factor.
Solution Approach 2:
The system changes the electrical parameters of the capacitor bank by altering connection topology. This allows the same physical capacitors to provide different equivalent capacitance values depending on whether they are connected in series or parallel, optimizing both hold-up time and size efficiency.
3Adaptability or versatility
If high voltage rating capacitors are used to handle maximum AC input voltage, then the power supply can accept high voltage inputs, but the capacitor cost and size increase
Solution Approach 1:
Instead of using one high-voltage-rated capacitor, the system uses multiple lower-voltage-rated capacitors connected in series. This segmentation allows each individual capacitor to be manufactured at lower cost while collectively handling the maximum voltage through series addition of voltage ratings.
Solution Approach 2:
The system dynamically switches between series and parallel capacitor configurations based on input voltage level. When high voltage is detected, capacitors are connected in series to distribute the voltage stress. When low voltage is detected, they are connected in parallel, allowing the use of lower-voltage-rated, lower-cost 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
The solution significantly reduces the physical size and cost of the power supply by minimizing the volume of bulk capacitors required, achieving a wide operating voltage range while maintaining necessary hold-up times.
Implementation Method 1
a filter that couples a plurality of capacitors in series to the rectified voltage in a first configuration based on the first control signal and couples the plurality of capacitors in parallel to the rectified voltage in a second configuration based on the second control signal
Data Source
AI summary
A configurable impedance circuit includes a controller that senses a rectified voltage and generates a first and second control signals based on a comparison of the rectified voltage to at least one threshold voltage. The configurable impedance circuit also includes a filter for filtering the rectified voltage that couples a plurality of capacitors in series to the rectified voltage in a first configuration based on the first control signal and couples the plurality of capacitors in parallel to the rectified voltage in a second configuration based on the second control signal.