Inductive Overvoltage Feedback for PFC Bulk Capacitor Protection

Solution Overview

Problem

Conventional power supplies with resistive overvoltage protection feedback paths for PFC bulk capacitors face reliability issues due to component aging and contamination, leading to inaccurate voltage monitoring and increased power consumption.

Innovation Solution

Implementing inductive overvoltage feedback protection paths that are coupled to the PFC and PWM controller to monitor the voltage of PFC bulk capacitors, providing a redundant and contamination-resistant means of detecting overvoltage conditions, thereby ensuring the reliability and efficiency of overvoltage protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If resistive overvoltage protection feedback paths are used to monitor PFC bulk capacitor voltage, then overvoltage protection can be provided, but component aging and contamination lead to unreliable voltage monitoring and increased power consumption

Engineering Contradiction:

Improveovervoltage protection reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the resistive feedback path with an inductive feedback path that uses a transformer to sense the PFC bulk capacitor voltage. The transformer's secondary winding provides an isolated voltage signal proportional to the primary voltage, eliminating the need for high-voltage resistors and their associated power consumption and reliability issues.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The transformer acts as an intermediary device that couples the high-voltage PFC bulk capacitor to the low-voltage control circuitry. It provides galvanic isolation while transferring the voltage information, allowing accurate voltage monitoring without direct electrical connection and without the power loss inherent in resistive dividers.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If resistive feedback paths are used for voltage monitoring, then overvoltage protection is achieved, but component aging and contamination cause inaccurate voltage monitoring

Engineering Contradiction:

Improvevoltage monitoring accuracyVSAvoidfeedback path reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the resistive feedback path with an inductive feedback path that uses a transformer to sense the PFC bulk capacitor voltage. The transformer's secondary winding provides an isolated voltage signal proportional to the primary voltage, eliminating the need for high-voltage resistors and their associated power consumption and reliability issues.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The transformer acts as an intermediary device that couples the high-voltage PFC bulk capacitor to the low-voltage control circuitry. It provides galvanic isolation while transferring the voltage information, allowing accurate voltage monitoring without direct electrical connection and without the power loss inherent in resistive dividers.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If inductive overvoltage feedback protection paths are implemented, then reliability and power consumption are improved, but additional circuit components are required

Engineering Contradiction:

Improveovervoltage protection reliabilityVSAvoidcircuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The transformer serves multiple functions: it provides galvanic isolation between primary and secondary sides, steps down the high voltage to a usable level for the control IC, and provides the feedback signal for both voltage regulation and overvoltage protection. This multi-functionality reduces the need for separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 inductive overvoltage feedback paths enhance the reliability of PFC bulk capacitors, reduce power consumption, and comply with energy efficiency standards by providing accurate overvoltage protection without the limitations of resistive feedback paths.

Implementation Method 1

at least one inductive overvoltage protection (OVP) feedback path coupled to the PSU processing device, the inductive OVP path being inductively coupled to the primary winding of the transformer

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9466974B2Systems and methods for inductive overvoltage protection of PFC bulk capacitors in power supplies

Publication Date: 2016.10.11 DELL PROD LP

AI summary

Systems and methods are provided that may be implemented for overvoltage protection of bulk capacitors employed in power factor correction (PFC) circuitry components of switched mode power supply units (PSUs) using one or more inductive overvoltage feedback protection paths (OVPs) to monitor a voltage indicative of a PFC bulk capacitor by sensing the real time voltage at one or both of the primary and/or secondary side windings of a PSU transformer, and/or using an auxiliary windings of a PSU transformer.