Flyback Power Supply Beat Noise Reduction
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Solution Overview
Problem
Conventional flyback switching power supply apparatuses experience increased power consumption and beat noise at low load states due to reduced switching times, leading to potential peripheral component damage from excessive current during incidental failures.
Innovation Solution
A power supply apparatus with a transformer, switching element, detecting unit, and control unit that adjusts switching operations based on current detection, reducing switching times and minimizing beat noise by maintaining a shorter conducting period of the switching element and incorporating a diode-based current detection unit to manage excessive currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the number of switching times of the switching element is decreased to reduce power consumption at low load, then power consumption is reduced, but the switching frequency approaches audible frequency and causes beat noise from the transformer
Solution Approach 1:
The patent applies dynamics by making the switching frequency variable rather than fixed. The control unit dynamically adjusts the switching frequency based on the operating state of the power supply apparatus. At low load states, the switching frequency is increased beyond the audible range to eliminate beat noise, while at higher load states, the frequency can be reduced to save power. This dynamic adjustment resolves the contradiction between power consumption and noise generation.
Solution Approach 2:
The patent changes the parameter of switching frequency based on operating conditions. By detecting the output current or power consumption level, the control unit adjusts the switching frequency parameter: keeping it above the audible threshold (typically >20kHz) when power consumption is high to avoid noise, and allowing it to be optimized for efficiency when power consumption is low. This parameter change strategy resolves the trade-off between noise and energy efficiency.
2Use of energy by moving object
If the number of switching times of the switching element is decreased, then power consumption is reduced, but the current per switching event must increase which can cause peripheral component breakage during incidental failures
Solution Approach 1:
The patent implements feedback control by continuously monitoring the operating state (output current or power consumption) and adjusting the switching frequency accordingly. The control unit receives feedback about the current load condition and dynamically modifies the switching parameters. This feedback mechanism ensures that during incidental failures, the system can detect abnormal current levels and adjust switching parameters to prevent excessive current stress on peripheral components, thereby maintaining reliability while still optimizing power consumption under normal conditions.
Solution Approach 2:
The patent applies beforehand cushioning by designing the control system to anticipate and prevent potential component failures. The control unit monitors operating conditions and adjusts switching parameters proactively to keep current per switching event within safe limits for peripheral components. By maintaining switching frequency above certain thresholds and adjusting duty cycles appropriately, the system cushions against the risk of component breakage before it occurs, even during incidental failures.
3Object-generated harmful factors
If the switching frequency is increased to avoid audible beat noise, then noise is reduced, but power consumption increases
Solution Approach 1:
The patent applies dynamics by making the switching frequency variable rather than fixed. The control unit dynamically adjusts the switching frequency based on the operating state of the power supply apparatus. At low load states, the switching frequency is increased beyond the audible range to eliminate beat noise, while at higher load states, the frequency can be reduced to save power. This dynamic adjustment resolves the contradiction between power consumption and noise generation.
Solution Approach 2:
The patent utilizes periodic action with variable period (frequency). Instead of operating at a constant high frequency to avoid noise, the system uses periodic switching with the frequency adapted to the load condition. When noise reduction is critical (low load), the period is shortened (frequency increased) above audible range. When power efficiency is more important (high load), the period is lengthened (frequency reduced). This periodic action with adaptive timing resolves the noise-power consumption trade-off.
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 vibration noise from transformers at low load operations and minimizes peripheral component damage from switching element failures, ensuring stable power supply while maintaining efficient energy usage.
Implementation Method 1
a transformer (108) having a primary winding and a secondary winding, a switching element (107) for switching a current flowing in the primary winding of the transformer
Data Source
AI summary
The power supply apparatus includes a detecting unit that has a first detecting device, a second detecting device and a third detecting device, detects a current flowing into the primary winding, and outputs a voltage corresponding to the current, and a control unit that controls a switching operation of the switching element, an output voltage which the detecting unit outputs to the control unit includes a first output voltage at which the control unit stops an operation of the switching element at a time of the second state, a second output voltage at which the control unit stops the operation of the switching element at a time of the first state, a third output voltage at which the second detecting device is brought into a conducting state, and a fourth output voltage at which the third detecting device is brought into a conducting state.