Fan Motor Current Control Device Preventing Coil Burnout

Solution Overview

Problem

Existing current control devices for motors fail to effectively manage and reduce high operating currents, leading to motor burnout, as they do not address the root cause of excessive current generation.

Innovation Solution

A current control device comprising a current sampling module, signal generating module, and current controlling module that samples the operating current, generates a threshold signal, and adjusts the driving signal to prevent excessive current by comparing sampled and threshold signals to generate a motor protecting signal, which stops or decreases the driving signal when the current exceeds the threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transistors 142 and 143 are enabled to adjust driving currents 114 and 115, then the operating current of the coil 121 is decreased, but the root cause of excessive current is not eliminated and the transistors may fail when current exceeds their adjustment capability

Engineering Contradiction:

Improvecoil reliabilityVSAvoidcontrol circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The controller proactively monitors the operating current of the coil through current sampling before the transistors reach their failure point. By detecting current trends in advance and comparing sampled values against threshold values, the system takes preliminary protective action by disabling transistors 142 and 143 before excessive current can cause damage, rather than reacting after failure occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback by sampling the operating current of the coil and comparing it with predetermined threshold values. This feedback mechanism allows the controller to monitor current levels in real-time and adjust the control signals to transistors 142 and 143 dynamically, ensuring the current remains within safe operating limits while optimizing performance.

Inventive Principle:

Principle #23Feedback

2Reliability

If transistors 142 and 143 are used to control operating current, then coil burnout is prevented, but the driving currents 114 and 115 are not effectively decreased and the control is reactive rather than proactive

Engineering Contradiction:

Improvemotor reliabilityVSAvoidcurrent control efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The controller proactively monitors the operating current of the coil through current sampling before the transistors reach their failure point. By detecting current trends in advance and comparing sampled values against threshold values, the system takes preliminary protective action by disabling transistors 142 and 143 before excessive current can cause damage, rather than reacting after failure occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback by sampling the operating current of the coil and comparing it with predetermined threshold values. This feedback mechanism allows the controller to monitor current levels in real-time and adjust the control signals to transistors 142 and 143 dynamically, ensuring the current remains within safe operating limits while optimizing performance.

Inventive Principle:

Principle #23Feedback

3Device complexity

If no current monitoring is implemented, then the control device is simpler, but the motor is vulnerable to burnout from excessive operating current

Engineering Contradiction:

Improvecontrol device complexityVSAvoidmotor reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system implements continuous feedback by sampling the operating current of the coil and comparing it with predetermined threshold values. This feedback mechanism allows the controller to monitor current levels in real-time and adjust the control signals to transistors 142 and 143 dynamically, ensuring the current remains within safe operating limits while optimizing performance.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The current control device performs self-diagnosis and self-protection by automatically sampling its own output current, comparing it with threshold values, and adjusting transistor control signals accordingly. This self-service capability allows the system to protect itself from excessive current conditions without requiring external monitoring equipment or complex external control circuits.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS7598691B2Current control device and method

Publication Date: 2009.10.06 DELTA ELECTRONICS INC(CN)

AI summary

A current control device for a fan motor includes a current sampling module, a signal generating module, a current detecting module and a current controlling module. The current sampling module samples an operating current of the fan motor to generate a sampled current signal. The operating current is controlled according to a driving signal. The signal generating module generates a threshold current signal. The current detecting module receives the sampled current signal and the threshold current signal and generates a motor protecting signal according to the sampled current signal and the threshold current signal. The current controlling module receives the motor protecting signal and stops generating or decreases the driving signal according to the motor protecting signal.