Fan Control Device Reducing Starting Current via Preliminary Action

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Solution Overview

Problem

Conventional fan systems experience excessive starting current and increased temperature due to high initial rotation speeds when starting or restarting, leading to energy waste and potential fan damage.

Innovation Solution

A control device with a start controlling unit that outputs a start controlling signal based on a starting voltage and stops after a predetermined period, allowing the fan to start or restart at a lower rotation speed, thereby reducing the starting current and preventing excessive temperature rise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the fan starts at high rotation speed to meet heat dissipation requirements, then the heat dissipation performance is improved, but the starting current becomes excessive and energy is wasted

Engineering Contradiction:

Improveheat dissipation performanceVSAvoidstarting current

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

The control device outputs a start controlling signal before the fan is actually needed to rotate at high speed, preparing the system in advance. This preliminary action allows the fan to start at a lower speed and then gradually increase to the required speed, avoiding excessive starting current while still meeting heat dissipation requirements when needed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control device dynamically adjusts the fan's rotation speed over time by outputting a start controlling signal for a predetermined period, then transitioning to normal speed control based on heat dissipation needs. This dynamic adjustment resolves the contradiction between high starting current and energy efficiency by making the speed profile adaptive rather than static.

Inventive Principle:

Principle #15Dynamics

2Temperature

If the fan starts at high rotation speed to ensure immediate cooling, then the cooling response time is reduced, but the fan temperature increases and damage risk rises

Engineering Contradiction:

Improvecooling response timeVSAvoidfan temperature and damage risk

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The control device initiates a predetermined period timing operation when the start controlling signal is output, preparing for the transition from start mode to normal control mode. This preliminary timing action ensures that the fan has sufficient time to start safely at lower speed before full cooling demand is applied, reducing thermal stress on the fan while maintaining cooling effectiveness.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control device provides a cushioning period during the predetermined time interval where the fan accelerates gradually rather than immediately reaching high speed. This beforehand cushioning protects the fan from excessive thermal and mechanical stress during startup, reducing damage risk while still enabling rapid cooling response when the predetermined period expires and normal control begins.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Measurement precision

If the control device waits for the target rotation speed controlling signal to reach desired voltage level, then the rotation speed control precision is improved, but the starting time is delayed

Engineering Contradiction:

Improverotation speed control precisionVSAvoidstarting time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The control device performs the predetermined period timing operation in advance, before normal rotation speed control begins. This preliminary action allows the system to start the fan immediately with a start controlling signal without waiting for the target rotation speed controlling signal to reach its desired voltage level, thus reducing starting time while maintaining control precision during the normal operation phase.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control device dynamically switches between two control modes: a preliminary start mode using the start controlling signal for immediate response, and a normal control mode using the target rotation speed controlling signal for precise speed regulation. This dynamic transition resolves the contradiction by separating the time-critical startup phase from the precision-critical operation phase.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7570009B2Fan system and its control device and control method

Publication Date: 2009.08.04 DELTA ELECTRONICS INC(CN)

AI summary

A control device of a fan system, which has at least one fan, receives a starting voltage. The control device includes a start controlling unit and a driving unit. The start controlling unit receives the starting voltage and outputs a start controlling signal according to the starting voltage. After a predetermined period, the start controlling unit stops sending the start controlling signal. The driving unit is electrically connected to the start controlling unit and the fan, respectively. The driving unit receives the start controlling signal for controlling the rotation speed of the fan.