DC Fan Motor Startup Stabilization via Adaptive Command Value

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Solution Overview

Problem

DC fan motors experience unstable activation and potential overcurrent issues when starting due to individual component variations and environmental factors, making it difficult to determine a stable initial command value for quick and stable activation.

Innovation Solution

A fan motor system that includes a command value outputting unit increasing the command value from a predetermined initial value, a start detecting unit that records the rotation start command value when motor activation is detected, and a recording unit that determines the initial value based on past activation data to stabilize motor activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If an initial command value larger than 0 V is suddenly applied to a DC fan motor in the stopped state, then the activation time is shortened, but the operation becomes unstable and may fall into an overcurrent state due to individual differences of component parts and environmental conditions

Engineering Contradiction:
Improveactivation timeVSAvoidactivation stability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The system performs preliminary action by gradually increasing the command value from a relatively small value before reaching the target value, rather than suddenly applying a large initial command value. This gradual increase allows the motor to activate smoothly without causing overcurrent issues or operational instability, while still reducing activation time compared to starting from 0 V.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention applies dynamics by making the command value increase dynamically and gradually rather than being fixed or sudden. The command value is adjusted progressively from a small initial value toward the target value, allowing the motor to adapt to changing conditions during activation and avoiding the overcurrent problems associated with sudden large voltage applications.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If a fixed initial command value is used during activation, then the activation process is simplified, but it is difficult to determine a fixed value that works for all motors due to characteristic variations

Engineering Contradiction:
Improvecontrol complexityVSAvoidmotor characteristic adaptation
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system changes parameters by using a gradually increasing command value approach instead of a fixed initial value. This parameter change strategy allows the control method to adapt to different motor characteristics and environmental conditions, as the gradual increase can be adjusted based on motor response without requiring complex pre-calibration for each motor type.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention incorporates feedback mechanisms that allow the control system to monitor motor activation progress and adjust the command value increase rate accordingly. This feedback enables the system to adapt to individual motor characteristics during the activation process, ensuring stable operation across different motor types without requiring complex pre-programming for each specific motor.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3220533B1Fan motor system, air conditioner, fan motor control method and program
Publication Date: 2018.10.31 MITSUBISHI HEAVY IND THERMAL SYST
  • EP3220533B1 patent drawingFigure 1
  • EP3220533B1 patent drawingFigure 2
  • EP3220533B1 patent drawingFigure 3

AI summary

Abstract: A fan motor system (1) is provided with: a fan motor unit (10) comprising a motor (101) and a controller (100) which controls the rotational speed of the motor (101) in accordance with an input command value; a command value outputting portion (110) which, when the motor (101) in a stopped state is activated, outputs the command value to the controller (100) while increasing the command value from a prescribed initial value; a startup detecting portion (111) which detects the start of rotation of the motor (101) on the basis of the actual rotational speed of the motor (101); and a startup command value recording portion (112) which acquires and records a rotation startup command value, which is the command value output by the command value outputting portion (110) at a time comesponding to the time at which the start of rotation is detected. The command value outputting portion (110) determines the initial value with reference to the recorded rotation startup command value, when the motor (101) is activated.