Rectifier Circuit with Switchable Capacitance for High Power Density
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Solution Overview
Problem
Conventional AC/DC power supplies with two-stage conversion circuits face challenges in power factor correction, requiring large capacitors with high capacitance and withstand voltage, leading to increased volume and reduced power density due to the need to manage varying input voltages effectively.
Innovation Solution
The proposed AC/DC power supply incorporates a rectifier circuit with a filter circuit that operates in two modes, using capacitors with different capacitance values and a switch to selectively connect them, allowing the supply voltage to follow DC pulsating voltage during one interval and exceed it during another, thereby reducing the size of the filter circuit and increasing power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If large capacitors with high capacitance and withstand voltage are used to manage varying input voltages, then the power supply can handle voltage variations effectively, but the volume increases and power density decreases
Solution Approach 1:
The patent applies dynamics by making the capacitance value changeable during operation. The filter circuit dynamically switches between different capacitance values based on the input voltage level and operating conditions. This allows the system to adapt to varying input voltages without requiring a permanently large capacitor, thereby reducing overall volume while maintaining adaptability.
Solution Approach 2:
The patent changes the parameter of capacitance from a fixed value to a variable value. By using a switch to selectively connect different capacitors or different portions of a capacitor, the effective capacitance is adjusted according to operating conditions. This parameter change enables the system to achieve the required voltage management with smaller overall capacitor volume.
2Reliability
If large capacitors are used to ensure normal operation across different input voltage levels, then reliability is improved, but device volume increases
Solution Approach 1:
The filter circuit is made dynamic by enabling real-time switching between different capacitance configurations. This dynamic adjustment ensures that the circuit maintains reliable operation across different input voltage levels while optimizing the use of capacitor volume, avoiding the need for oversized capacitors that would be required in a static design.
Solution Approach 2:
The patent segments the filter circuit into multiple capacitor units or sections that can be independently switched. By dividing the total capacitance into segments, the system can select appropriate combinations to maintain reliability under different operating conditions without requiring a single large capacitor, thus reducing overall volume.
3Productivity
If the filter circuit size is reduced to increase power density, then power density improves, but the ability to manage varying input voltages may be compromised
Solution Approach 1:
The patent resolves this contradiction by making the filter circuit dynamic. The switchable capacitance configuration allows the reduced-size filter circuit to adapt its characteristics in real-time, maintaining the ability to manage varying input voltages effectively despite the smaller overall size. This dynamic behavior enables high power density without sacrificing voltage management capability.
Solution Approach 2:
By changing the effective capacitance parameter dynamically, the patent enables a smaller filter circuit to achieve the same voltage management performance as a larger static circuit. The switch selectively connects different capacitance values based on operating conditions, allowing the compact circuit to maintain adaptability across varying input voltages.
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 a more compact design by prolonging the energy supply time from the AC input voltage, reducing the required capacitance and volume of capacitors, while maintaining normal operation across different input voltage levels, thus enhancing power density.
Implementation Method 1
a capacitor C, in order to generate supply voltage Vin. The subsequent stage of the AC/DC power supply can be a DC/DC converter
Data Source
AI summary
A rectifier circuit applied in an AC/AC power supply, the rectifier circuit including: a filter circuit configured to receive a DC pulsating voltage, and to generate a supply voltage, where the supply voltage follows the DC pulsating voltage during a first time interval of an operation cycle; and where during a second time interval of the operation cycle, a value of the supply voltage is greater than the value of the supply voltage at an end of the first time interval, in order to reduce a size of the filter circuit.