Boost Regulator for Fan Motor Noise Reduction
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Solution Overview
Problem
Communication equipment fans generate electrical noise due to current pulses, which couple into power supplies and communication lines, posing stringent noise reduction challenges, especially in systems like POTS, where low-frequency noise requires large filters, often leading to design and production issues.
Innovation Solution
A boost regulator is used to provide a constant input current to the fan motor, reducing noise by stabilizing the input current within a selected tolerance over a timescale longer than the frequency, thereby minimizing noise coupling into power supplies and communication lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive filters are used to attenuate low-frequency electrical noise from fan motors, then noise requirements can be met, but the filter size becomes unacceptably large and increases device complexity
Solution Approach 1:
The patent changes the electrical parameters of the power supply system by introducing a regulated power supply that maintains constant voltage and current. This parameter change eliminates the need for large passive filters by addressing the root cause of noise (current pulses) rather than attempting to filter the noise after it is generated. The regulated power supply maintains voltage within ±1% and current within ±5% over the fan operating frequency range, thereby meeting noise requirements without requiring large filter components.
Solution Approach 2:
The patent replaces the mechanical/passive filtering approach (large inductors and capacitors) with an active electronic regulation system. Instead of using passive RC or LC filters that require large component values to attenuate low-frequency noise, the invention uses an active regulated power supply with control circuitry that dynamically adjusts to maintain stable electrical parameters, thereby substituting a compact electronic system for bulky passive filters.
2Device complexity
If fan motor current pulses are allowed to draw directly from power supply, then device complexity is reduced, but electrical noise couples onto power supply and communication lines
Solution Approach 1:
The patent introduces a regulated power supply as an intermediary device between the power source and the fan motor. This intermediary actively controls the current delivery to the fan motor, preventing the direct coupling of noise onto the power supply and communication lines. The regulated power supply acts as a buffer that isolates the communication equipment from the noisy fan motor while still providing sufficient power for operation.
Solution Approach 2:
The regulated power supply employs feedback control mechanisms to monitor and adjust the current delivered to the fan motor. By continuously monitoring the electrical parameters and making real-time adjustments, the system maintains stable operation and prevents noise generation at its source, rather than attempting to mitigate noise after it is created.
3Loss of time
If fan design is finalized without considering noise requirements, then development time is reduced, but re-design and re-production costs increase significantly
Solution Approach 1:
The patent applies preliminary action by incorporating the regulated power supply design into the fan motor assembly during the initial design phase. By pre-planning and pre-integrating the noise reduction solution into the fundamental power delivery architecture, the invention eliminates the need for later re-design and re-production. The regulated power supply is designed from the outset to meet noise requirements, thereby preventing costly iterative modifications.
Solution Approach 2:
The patent merges the regulated power supply functionality directly into the fan motor assembly, creating an integrated unit where the power delivery and noise reduction functions are combined. This integration ensures that noise requirements are built into the core design rather than added as a separate consideration, thereby avoiding the need for subsequent re-design and re-production efforts.
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 boost regulator significantly reduces electrical noise, meeting stringent noise requirements, such as psophometric noise levels below 0.4 mV, by maintaining a stable input current, thus improving fan design efficiency and reducing re-design and re-production costs.
Implementation Method 1
a boost regulator configured to provide an output current to a fan motor using an input current provided at an input voltage by a power supply
Data Source
AI summary
The present invention provides a method and apparatus for providing power to a fan motor. One embodiment of the apparatus includes a boost regulator configured to provide an output current to a fan motor using an input current provided at an input voltage by a power supply. The fan motor is configured to draw the output current at a first frequency and the input current is constant within a first selected tolerance over a time scale longer than indicated by the first frequency.