Digital Filter Coefficient Optimization for Switched Mode Power Supplies
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Solution Overview
Problem
Conventional digital control systems for switched mode power supplies face challenges in optimizing and programming filter compensation coefficients, leading to increased complexity and size in distributed power systems, particularly in coordinating and monitoring point-of-load regulators.
Innovation Solution
A system and method that utilize a digital controller with a serial data bus to periodically store feedback measurement samples, calculate optimized filter coefficients, and communicate them to the digital filter, incorporating a noise source to inject a symmetrical noise signal for improved loop response analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-connection parallel bus is used to coordinate and monitor POL regulators, then control and monitoring capability is improved, but system complexity and size increase
Solution Approach 1:
The patent extracts the complex coordination and monitoring functions from the POL regulators themselves and relocates them to a separate system controller. This allows the POL regulators to be simpler while the system controller handles the complex tasks of coefficient optimization, programming, and monitoring across multiple regulators.
Solution Approach 2:
The system controller serves multiple functions: it optimizes filter coefficients, programs POL regulators, monitors system operation, and coordinates multiple POL regulators. This multi-functional approach consolidates complexity into a single controller rather than distributing it across multiple connections.
2Quantity of substance
If entirely digital circuitry is used instead of analog components, then physical space and power consumption are reduced, but implementation of programmability and adaptive control becomes more challenging
Solution Approach 1:
The system controller pre-calculates and stores optimized filter coefficients for various operating conditions before they are needed. When the POL regulator needs to adapt to changing conditions, it simply retrieves pre-computed coefficients rather than performing complex real-time calculations, making digital adaptation feasible.
Solution Approach 2:
The system controller acts as an intermediary that performs the complex adaptive control calculations externally and communicates only simple coefficient values to the POL regulator. This allows the POL regulator to remain a simple digital device while still achieving adaptive control through the intermediary controller.
3Stability of the object's composition
If filter compensation coefficients are fixed, then system stability is maintained, but optimization for particular load conditions becomes impossible
Solution Approach 1:
The system implements dynamic filter coefficients that can change based on operating conditions. The system controller continuously monitors load conditions and adjusts the filter coefficients accordingly, allowing the system to adapt to varying load conditions while maintaining stability through controlled changes.
Solution Approach 2:
The system uses feedback from load monitoring to dynamically adjust filter coefficients. The system controller receives feedback about actual operating conditions and uses this information to optimize the filter coefficients for current load conditions, creating a closed-loop adaptive control system.
Data Source
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AI summary
A method and system for optimizing the digital filter compensation coefficients of a digitally controlled switched mode power supply within a distributed power system is disclosed A power control system comprises at least one point-of-load (POL) regulator having a power conversion circuit adapted to convey power to a load and a digital controller coupled to the power conversion circuit though a feedback loop The digital controller includes a digital filter having a transfer function defined by plural filter coefficients The digital controller periodically stores samples of the feedback measurement The system controller retrieves stored samples from the digital controller via a sepal data bus After retpeving a pre-determined number of the samples, the system controller calculates optimized filter coefficients for the digital filter and communicates the optimized filter coefficients to the digital controller for use in the digital filter