Dual Feedback Loop Power Converter Voltage Overshoot Compensation

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Solution Overview

Problem

Conventional power converters experience voltage overshoot during ramping up or down due to delays in the system, which can lead to inefficiencies and potential damage to electronic components, and fail to quickly adjust output voltage in response to changing load conditions such as temperature.

Innovation Solution

A power conversion circuit with two feedback loops, where a second feedback loop operates at a lower bandwidth than the first, allowing for a final adjustment to the commanded voltage to compensate for overshoot and enable faster voltage stabilization and power factor correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single feedback loop is used to control output voltage, then the circuit is simple, but voltage overshoot occurs during ramping due to system delay

Engineering Contradiction:

Improvefeedback circuit structureVSAvoidvoltage control accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The feedback control circuit is segmented into two independent feedback loops: a first feedback loop for basic voltage regulation and a second feedback loop for overshoot compensation. Each loop has its own feedback resistor and control path, allowing them to operate independently with different bandwidths and control strategies.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second feedback loop acts as an intermediary that detects voltage overshoot conditions and generates compensatory control signals. This intermediary loop monitors the output voltage and intervenes by adjusting the commanded voltage to counteract overshoot before it affects the load.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If the feedback loop operates at high bandwidth for fast response, then voltage can be adjusted quickly, but overshoot increases due to system delay

Engineering Contradiction:

Improvevoltage adjustment speedVSAvoidvoltage accuracy

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The system dynamically switches between different feedback loop modes: the first feedback loop operates at high bandwidth for fast voltage adjustment, while the second feedback loop operates at lower bandwidth for stable overshoot compensation. The system adapts its control characteristics based on operating conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control system changes the effective feedback parameters by introducing the second feedback loop with different resistor values (Rf2, Rg2) compared to the first loop (Rf1, Rg1). This allows optimization of each loop for its specific function: speed for the first loop and precision for the second loop.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If voltage is ramped up quickly to reach goal voltage, then power efficiency improves, but overshoot can damage electronic components

Engineering Contradiction:

Improvevoltage ramping speedVSAvoidcomponent damage from overshoot

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The second feedback loop applies preliminary anti-action by detecting the tendency toward overshoot and generating compensatory control signals before the overshoot fully develops. This preemptive action counteracts the overshoot tendency and protects components from voltage excursions.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The control system performs preliminary action by using the second feedback loop to pre-adjust the commanded voltage based on predicted overshoot conditions. This preliminary adjustment prevents the overshoot from occurring in the first place, rather than correcting it after it happens.

Inventive Principle:

Principle #10Preliminary action

4Manufacturing precision

If a final adjustment is applied to commanded voltage to compensate for overshoot, then voltage accuracy improves, but the control circuit becomes more complex

Engineering Contradiction:

Improvevoltage accuracyVSAvoidfeedback control circuit

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The two feedback loops are merged at the control input stage, where their output signals are combined to generate the final control signal for the power converter. This merging allows both loops to work together synergistically, with the first loop providing fast response and the second loop providing precision correction.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8912770B2Power conversion feedback control circuit for reaching a goal voltage

Publication Date: 2014.12.16 ATMEL CORP

AI summary

A power conversion circuit of two feedback loops is disclosed that includes a feedback control circuit for ramping up or down a commanded voltage to a load (e.g., LEDs). The second feedback loop feeds into the first feedback loop, and the second feedback loop operates at a slower bandwidth than the first feedback loop. When ramping up or down the commanded voltage, a voltage overshoot results because of delay in the system. The overshoot can be compensated for by a final adjustment to the commanded voltage.