Fan Apparatus Back-EMF Braking Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing techniques for reducing motor rotation rate caused by external forces require external power supply, leading to increased power consumption.
Innovation Solution
A fan apparatus with a drive circuit including a braking MOSFET and a non-braking MOSFET, utilizing back-electromotive force to supply power to the braking MOSFET and apply an electromagnetic brake, allowing for reduced motor rotation rate without external power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If external power supply is used to reduce motor rotation rate, then motor braking is achieved, but power consumption increases
Solution Approach 1:
The motor's own back-electromotive force during rotation is utilized to power the braking MOSFET, enabling the system to brake itself without external power supply. The back-EMF generated by the rotating motor directly activates the braking circuit, making the system self-sufficient for braking operations.
Solution Approach 2:
The back-electromotive force, which is naturally generated during motor rotation, is converted into a useful resource to drive the braking MOSFET. This transforms the electrical energy that would otherwise be dissipated into a beneficial braking mechanism, eliminating the need for additional external power.
2Speed
If braking MOSFET is activated without back-electromotive force, then motor braking is achieved, but external power supply is required
Solution Approach 1:
The system uses its own operational characteristics (back-EMF generation during rotation) to power the braking function, eliminating the need for separate external power supply circuits and reducing overall system complexity.
Solution Approach 2:
The motor serves dual functions: it generates both the back-electromotive force needed for normal operation and the same back-EMF is utilized to power the braking MOSFET. This multi-functionality reduces the need for dedicated power supply components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces motor rotation rate while minimizing power consumption by leveraging back-electromotive force to apply an electromagnetic brake, achieving reduced power consumption and controlled motor braking.
Implementation Method 1
power by a back-electromotive force caused by rotation of the motor portion
Implementation Method 2
electromagnetic brake portion arranged to electromagnetically brake the motor portion by causing the braking MOSFET to enter an ON state
Data Source
AI summary
A fan apparatus has a drive circuit for an electrically-driven rotor, and includes a drive signal generating circuit portion for the electrically-driven rotor; an output stage including an upper MOSFET and a lower MOSFET; and a motor portion to be driven by the output stage. One of the upper MOSFET and the lower MOSFET is a braking MOSFET, while another of the upper MOSFET and the lower MOSFET is a non-braking MOSFET. The fan apparatus further includes a back-electromotive force supply portion arranged to supply, to the braking MOSFET, power by a back-electromotive force caused by rotation of the motor portion while a power supply voltage for the electrically-driven rotor is not being supplied; and an electromagnetic brake portion arranged to electromagnetically brake the motor portion by causing the braking MOSFET to enter an ON state through the power supplied by the back-electromotive force supply portion.