Fan Start-Up Control via Decreasing Drive Signal

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Solution Overview

Problem

Conventional fan start-up methods result in noticeable noise due to high energy driving signals used in open loop control stages without feedback adjustments, leading to overshoot in rotational speed and inefficient energy use.

Innovation Solution

A method involving a two-stage driving signal approach during fan start-up, where the signal value of the first driving signal gradually decreases to match the second driving signal, and a feedback-controlled third signal is applied after stabilization, reducing noise and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a driving signal with constant high energy is provided in the open loop control stage to obligately start the fan, then the fan can be reliably started, but obvious start-up noise occurs due to rotational speed overshoot

Engineering Contradiction:

Improvefan start-up reliabilityVSAvoidstart-up noise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by transitioning the driving signal from a static constant high energy state to a dynamic decreasing energy state. The control signal's energy is continuously reduced during the open loop control stage while maintaining the fan's rotational acceleration, thereby preventing overshoot and reducing noise without compromising start-up reliability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of driving signal energy from constant high value to continuously decreasing value. This parameter change allows the system to maintain sufficient torque for reliable fan start-up while progressively reducing the energy input to avoid rotational speed overshoot and associated noise during the acceleration phase.

Inventive Principle:

Principle #35Parameter changes

2Speed

If a driving signal with constant high energy is provided to the fan during start-up, then the fan reaches target rotational speed, but energy consumption is excessive

Engineering Contradiction:

Improvetarget rotational speedVSAvoidenergy consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent implements a dynamic energy reduction strategy where the driving signal's energy is continuously decreased during the open loop control stage. This dynamic adjustment maintains sufficient energy to achieve target rotational speed while minimizing excess energy consumption that would occur with constant high energy input.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms to monitor the fan's rotational speed and adjust the driving signal energy accordingly. By using feedback from the rotational speed information, the system optimizes energy delivery, reducing energy consumption while ensuring the fan reaches the target rotational speed efficiently.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11473584B2Method of starting a fan using an open loop starting stage with a decreasing drive signal value

Publication Date: 2022.10.18 DELTA ELECTRONICS INC(CN)

AI summary

A method for controlling a fan in a fan start-up stage including a first time period and a second time period comprises the following steps of: during the first time period, continuously providing a first driving signal to drive the fan; and during the second time period, continuously providing a second driving signal to drive the fan; wherein, during the first time period the signal value (driving energy) of the first driving signal gradually decreases until being equal to the signal value of the second driving signal, and the signal value of the first driving signal is initially greater than the signal value of the second driving signal. A fan is also disclosed.