Digital Controller for Converter Systems Limiting Oscillation
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Solution Overview
Problem
Digitally controlled converter systems face limit-cycle oscillation due to low DPWM resolution, leading to unstable output voltage and difficulty in distinguishing noise from EMI, which is exacerbated by the need for high switching frequencies and low system clock frequencies, resulting in low DPWM resolution and correspondingly low ADC resolution, affecting system performance.
Innovation Solution
A digitally controlled converter system that generates a digital error signal and a PWM signal based on a digital control signal to regulate the output voltage, employing a digital controller with a DPWM module, error generator, and duty-cycle generator to switch between steady and dynamic control modes, avoiding limit-cycle oscillation by adjusting the duty-cycle signal accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the DPWM resolution is increased to avoid limit-cycle oscillation, then the output voltage stability is improved, but the system cost and device complexity increase significantly
Solution Approach 1:
The patent divides the control system into distinct functional modules: a determination module that identifies limit-cycle oscillation conditions, and a adjustment module that modifies control parameters. This segmentation allows the system to maintain simplicity while addressing stability issues through modular functionality.
Solution Approach 2:
The patent dynamically changes control parameters (such as duty cycle adjustment量 or sampling frequency) based on detected oscillation conditions, rather than using fixed high-resolution DPWM. This parameter adaptation resolves the contradiction by achieving stability through variable control rather than fixed high complexity.
2Productivity
If the switching frequency is increased to improve converter performance, then the output voltage regulation is improved, but the DPWM resolution decreases leading to limit-cycle oscillation
Solution Approach 1:
The patent implements dynamic adjustment of control parameters based on real-time system state detection. When limit-cycle oscillation is detected, the system dynamically modifies the duty cycle adjustment amount or sampling frequency, allowing high switching frequency operation without being constrained by fixed low DPWM resolution.
Solution Approach 2:
The patent employs feedback mechanisms where the determination module continuously monitors system state and feeds back to the adjustment module. This closed-loop feedback allows the system to compensate for low DPWM resolution effects by detecting oscillation patterns and adjusting control parameters accordingly, maintaining performance despite high switching frequency constraints.
3Device complexity
If the ADC resolution is decreased to match the low DPWM resolution, then the system cost is reduced, but the transient response performance and output voltage accuracy deteriorate
Solution Approach 1:
The patent performs preliminary detection of limit-cycle oscillation conditions before they significantly degrade performance. By proactively identifying oscillation patterns early, the system can adjust control parameters in advance, maintaining output voltage accuracy even with lower ADC resolution than would traditionally be required.
Solution Approach 2:
The feedback mechanism continuously monitors output voltage and control parameters, enabling the system to detect and correct for quantization errors introduced by lower-resolution ADC and DPWM combinations. This real-time feedback compensation maintains measurement precision without requiring high-resolution hardware.
Data Source
AI summary
The embodiments of the present invention illustrate a means for digitally controlling a converter system and associated method. Wherein the means for digitally controlling a converter system comprises a means for generating a digital error signal according to an output voltage of the converter system and a reference voltage, a means for generating a digital control signal according to a digital reference signal and the digital error signal, and a means for generating a PWM signal according to the digital control signal in order to control the converter system. The means for digitally controlling a converter system and associated method at least alleviate the problem of limit-cycle oscillation, and promote the performance of system transient response and accuracy.