ACDC Power Supply Coil Bypass for Low-Power Vibration Suppression
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Solution Overview
Problem
Conventional power source devices in image forming apparatuses, such as printers and copiers, suffer from audible vibrations due to ceramic capacitors expanding and contracting with voltage changes, leading to increased substrate size and cost, and ineffective resonance cancellation with nearby coils.
Innovation Solution
A power source device with an ACDC converter, capacitors, a coil, and a switch element, controlled to short-circuit the coil when power output is below a threshold, reducing audible vibrations by suppressing resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic capacitor is used to improve EMC, then electromagnetic compatibility is improved, but audible vibrations are generated due to electrostrictive effect
Solution Approach 1:
The invention utilizes the electrostrictive effect of the ceramic capacitor, which causes vibration, and converts this harmful vibration into a beneficial power factor improvement function by resonating the capacitor with a coil. The vibration that was previously harmful is now harnessed to achieve dual functionality: maintaining EMC performance while improving power factor.
Solution Approach 2:
The ceramic capacitor is made to serve multiple functions: (1) maintaining electromagnetic compatibility through proper placement in the power source line, and (2) improving power factor through resonance with the coil. This eliminates the need for separate components and reduces overall device complexity.
2Object-affected harmful factors
If another ceramic capacitor is added to cancel vibration, then sounding is reduced, but substrate size and cost are increased
Solution Approach 1:
Instead of adding another capacitor to cancel the vibration, the invention converts the vibration itself into a useful function by resonating it with a coil. This approach eliminates the need for additional vibration-canceling components, thereby reducing substrate size and cost while maintaining the desired effect.
Solution Approach 2:
The invention changes the operational parameters of the ceramic capacitor by introducing a resonance frequency through the coil. By tuning the resonance frequency to match the electrostrictive vibration frequency, the system transforms the vibration from a harmful phenomenon into a useful power factor improvement mechanism.
3Power
If a coil is added to improve power factor, then power factor is improved, but resonance with ceramic capacitor generates audible vibrations
Solution Approach 1:
The invention acknowledges that resonance between the coil and ceramic capacitor generates audible vibrations, but instead of avoiding the resonance, it harnesses this resonance to simultaneously achieve power factor improvement. The key insight is that the same resonance condition that causes vibration also enables the power factor correction function.
Solution Approach 2:
The invention introduces dynamic control through a switching element that selectively connects or disconnects the coil from the power source line based on operational conditions. This dynamic approach allows the system to activate the coil for power factor improvement only when necessary, and to suppress vibrations by disconnecting the coil when it would cause audible noise.
4Object-affected harmful factors
If switch element is used to control coil, then vibrations are reduced in low-power mode, but power factor improvement is compromised in high-power mode
Solution Approach 1:
The switching element dynamically adjusts the circuit configuration based on power consumption levels. In low-power modes, the switch disconnects the coil to prevent vibrations. In high-power modes, the switch connects the coil to enable power factor improvement. This dynamic adaptation resolves the contradiction by optimizing performance for each operational condition.
Solution Approach 2:
The switching element operates periodically or conditionally based on the power consumption state of the image forming apparatus. By monitoring power consumption and switching the coil connection accordingly, the system achieves both vibration reduction and power factor improvement at appropriate times.
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 audible frequency vibrations by more than 10 dB in low-power modes, enhancing user comfort and reducing substrate size and cost without compromising power factor improvement in higher power modes.
Implementation Method 1
Some capacitors, such as a ceramic capacitor, include a feature (an electrostrictive effect) that expands and contracts by applying voltage and vibrate corresponding to a change of an applying voltage.
Implementation Method 2
it is difficult to reduce the sounding by resonance because the ceramic capacitor is not able to cancel the resonance with a coil which is located in vicinity of the ceramic capacitor
Data Source
AI summary
A power source device includes an ACDC converter, a capacitor connected between a power source line of the power source device and a ground, and a coil connected to the power source line between an AC power source and the ACDC converter. A switch is connected to the coil in parallel and short-circuits both ends of the coil by being turned on. A controller controls the switch to turn on or off and controls the switch to turn off in a case in which the electric power is a predetermined electric power or more, and controls the switch to turn on in a case in which the electric power is less than the predetermined electric power.