Active Power Factor Corrector Circuit with Dynamic Switching Frequency

Solution Overview

Problem

Existing power factor corrector circuits struggle to maintain a high power factor over a range of load currents, particularly in applications where load current varies, leading to inefficiencies and increased costs due to higher energy losses and larger equipment requirements.

Innovation Solution

An active power factor corrector circuit with a controller that adjusts the switching frequency based on the battery charging curve, allowing for optimal power factor correction across varying load currents by varying the switching frequency in response to changing load conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed switching frequency is used in the power factor corrector circuit, then the circuit design is simpler, but the power factor cannot be maintained at high levels across varying load currents

Engineering Contradiction:

Improvepower factor maintenance across load rangeVSAvoidswitching frequency control

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic switching frequency adjustment by varying the switching frequency based on the detected load current magnitude. The controller automatically adapts the switching frequency to maintain optimal power factor correction performance across different operating conditions, transforming a static design into a dynamic adaptive system.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the switching frequency parameter in response to varying load conditions. By detecting load current and adjusting the switching frequency accordingly, the system optimizes power factor correction efficiency without requiring complex additional hardware, simply by modulating the operating frequency parameter.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If larger equipment is used to handle high current at low power factor, then the system can handle the current, but the equipment cost and energy loss increase

Engineering Contradiction:

Improvecurrent handling capabilityVSAvoidenergy loss in distribution system

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent converts the harmful effect of low power factor (which causes high current and energy loss) into a beneficial control signal. By detecting the load current and using it to adjust the switching frequency, the system turns the problem of varying current into an opportunity to optimize correction performance, thereby reducing energy losses without requiring oversized equipment.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If the switching frequency is increased to improve power factor correction, then the power factor improves, but the switching losses increase

Engineering Contradiction:

Improvepower factor correction performanceVSAvoidswitching losses

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent implements dynamic switching frequency adjustment by varying the switching frequency based on the detected load current magnitude. The controller automatically adapts the switching frequency to maintain optimal power factor correction performance across different operating conditions, transforming a static design into a dynamic adaptive system.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the switching frequency parameter in response to varying load conditions. By detecting load current and adjusting the switching frequency accordingly, the system optimizes power factor correction efficiency without requiring complex additional hardware, simply by modulating the operating frequency parameter.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9450436B2Active power factor corrector circuit

Publication Date: 2016.09.20 INFINEON TECHNOLOGIES AG

AI summary

In accordance with an embodiment, a circuit includes a direct current (DC) output configured to be coupled to a rechargeable battery and a power factor corrector circuit coupled to the DC output, where the power factor corrector circuit includes a controller, and where the controller is configured to determine a switching frequency of the power factor corrector circuit in accordance with a battery charging curve of the rechargeable battery.