Tunable Passive Component Power Filter Resonance Control
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Solution Overview
Problem
Switched mode power supplies face challenges in maintaining high attenuation filtering at a specific frequency due to variations in operating conditions, such as changing loads or temperatures, which degrades the performance of fixed component-based resonant filters.
Innovation Solution
A tunable passive component system in a switched mode power supply that includes a control function circuit to automatically adjust the passive component values based on voltage conditions, maintaining resonance at a selected frequency, thereby ensuring consistent high attenuation filtering across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fixed component based resonant filters are used, then high attenuation at specific frequency is achieved, but variations in operating conditions cause degradation of filtering performance
Solution Approach 1:
The patent applies dynamics by making the filter components adjustable rather than fixed. The resonant frequency of the filter can be dynamically tuned to track the PWM switching frequency despite variations in operating conditions such as load changes or temperature variations. This resolves the contradiction by maintaining reliable filtering performance (improving reliability) while using resonant filters that inherently have low loss (maintaining energy efficiency).
Solution Approach 2:
The patent changes the parameters of the filter components (inductance and capacitance values) to maintain resonant frequency alignment with the PWM switching frequency. By adjusting these parameters in response to operating condition changes, the filter maintains its high attenuation capability at the target frequency, thus preserving both low loss and consistent performance.
2Loss of energy
If high quality factor is set for resonant filter tank, then high attenuation is achieved, but effective bandwidth becomes very narrow
Solution Approach 1:
The patent makes the resonant filter dynamically adjustable, allowing the high Q-factor design to track the PWM switching frequency. This dynamic tuning capability enables the narrow bandwidth filter to remain effective across varying operating conditions, resolving the contradiction between achieving high attenuation with low loss and maintaining adaptability to frequency variations.
Solution Approach 2:
The system uses feedback to detect the PWM switching frequency and adjusts the resonant filter parameters accordingly. This feedback mechanism ensures that the narrow bandwidth high Q-factor filter remains centered at the correct frequency, maintaining both low loss performance and adaptability to changing operating conditions.
3Ease of manufacture
If fixed component values are used, then manufacturing simplicity is maintained, but filtering performance degrades under varying loads or temperatures
Solution Approach 1:
The patent transitions from fixed to adjustable filter components, where the inductance and capacitance values can be dynamically tuned. This dynamic capability allows the filter to maintain consistent attenuation performance under varying loads and temperatures, resolving the contradiction between manufacturing simplicity and performance reliability.
Solution Approach 2:
The filter system automatically adjusts its own parameters in response to operating conditions without requiring complex external intervention. The control circuit monitors the PWM frequency and self-adjusts the resonant filter components to maintain optimal performance, achieving reliability improvement while keeping the manufacturing process relatively simple.
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 enables high attenuation filtering at a target frequency under changing conditions, reducing filter component sizes and losses, and improving dynamic performance, with a bandwidth that is lower than the main controller's to avoid interference.
Implementation Method 1
maintain resonance of the tunable output filter at about the selected frequency
Data Source
AI summary
A method of controlling a tunable passive component in a pulse width modulation controlled switched mode power supply (SMPS) having a power input and an output with tunable passive component power filter. The method includes operably connecting and supplying power relative to a circuit ground to a DC bus, converting a voltage on the DC bus to an output voltage by operating a first switching device and a second switching device at a selected frequency, and filtering the output voltage with a tunable output filter, the tunable output filter including a tunable passive component responsive to a control function circuit configured to automatically tune the tunable passive component value based on a voltage associated with operation of the power supply to maintain resonance of the tunable output filter at about the selected frequency.