Power Supply Device Switching Frequency Control
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Solution Overview
Problem
Switching power supplies face challenges in reducing vibration noise and standby power consumption, particularly in low load states where the switching frequency falls within the human audible range, leading to increased power loss and noise.
Innovation Solution
A power supply device with a transformer having a primary, secondary, and auxiliary winding, a switching unit, current detection unit, control unit, and correction unit that adjusts switching operations based on induced voltages in the auxiliary winding to maintain the switching frequency out of the audible range and minimize power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the switching frequency is reduced to lower switching losses, then power consumption is improved, but vibration noise increases and falls into the audible range
Solution Approach 1:
The patent applies dynamics by making the switching frequency adjustable rather than fixed. The control unit dynamically changes the switching frequency based on load conditions, extending the on-state time period at lower frequencies to reduce switching losses while maintaining frequency above the audible range to suppress vibration noise. This dynamic adaptation resolves the contradiction between reducing energy loss and avoiding harmful noise.
Solution Approach 2:
The patent changes the parameter of switching frequency based on operational conditions. By varying the switching frequency and on-state time period according to load demands, the system optimizes the balance between switching losses and vibration noise. The control unit adjusts these parameters to keep the frequency out of the audible range while minimizing energy loss, directly addressing the technical contradiction.
2Loss of energy
If the on-state time period is extended to increase energy per switching operation, then switching losses are reduced, but the switching frequency falls into the audible range causing vibration noise
Solution Approach 1:
The system dynamically adjusts both the on-state time period and switching frequency together rather than independently. The control unit coordinates these parameters to ensure that when the on-state time is extended to reduce switching losses, the switching frequency remains above the audible range. This coordinated dynamic adjustment prevents the harmful vibration noise while maintaining energy efficiency.
Solution Approach 2:
The patent simultaneously changes multiple parameters (on-state time period and switching frequency) to resolve the contradiction. By adjusting both parameters in coordination based on load conditions, the system achieves reduced switching losses while maintaining the switching frequency out of the audible range, thereby preventing vibration noise generation.
3Object-affected harmful factors
If the switching frequency is increased to move it out of the audible range, then vibration noise is reduced, but switching losses increase and power consumption rises
Solution Approach 1:
Rather than maintaining a fixed high switching frequency, the system dynamically adjusts the frequency based on actual load conditions. The control unit lowers the switching frequency when possible to reduce switching losses, while ensuring it remains above the audible range to suppress vibration noise. This dynamic approach resolves the contradiction by avoiding unnecessarily high frequencies that increase energy loss.
Solution Approach 2:
The patent optimizes the switching frequency parameter by changing it according to operational requirements. Instead of always operating at high frequency to avoid noise, the system adjusts the frequency to the minimum necessary value that still remains above the audible range, thereby minimizing switching losses while maintaining noise suppression.
4Use of energy by moving object
If the switching frequency is reduced in power saving mode to minimize power loss, then energy efficiency is improved, but the frequency falls into the audible range causing noise
Solution Approach 1:
The system applies dynamics by implementing different switching strategies for different operational modes. In power saving mode, the control unit dynamically adjusts the switching parameters to maintain frequency above the audible range while minimizing power loss. This mode-specific dynamic adjustment resolves the contradiction between energy efficiency and noise suppression in low-power operations.
Solution Approach 2:
The patent changes the switching frequency and on-state time period parameters specifically for power saving mode to achieve optimal balance. By adjusting these parameters to keep the frequency out of the audible range while minimizing switching operations, the system reduces power consumption without generating vibration noise, resolving the technical contradiction in power saving scenarios.
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 and standby power consumption by maintaining the switching frequency out of the audible range and minimizing power loss, even in low load states, thereby enhancing efficiency and reducing noise pollution.
Implementation Method 1
a transformer that includes a primary winding, a secondary winding and an auxiliary winding having a winding direction different from a winding direction of the primary winding
Implementation Method 2
a switching element, such as an FET (field-effect transistor), at a prescribed frequency and outputs a desired voltage
Implementation Method 3
a current detection unit that detects current flowing through the primary winding, and outputs a voltage according to the current
Implementation Method 4
a first voltage detection unit that detects a voltage induced in the auxiliary winding of the transformer
Data Source
AI summary
The power supply device includes a transformer that includes primary, secondary and auxiliary windings; a switching unit that switches current flowing to the primary winding of the transformer; a current detection unit that detects current flowing through the primary winding, and outputs a voltage according to the current; a control unit that controls switching operation of the switching unit, according to the voltage output from the current detection unit; a first voltage detection unit that detects a voltage induced in the auxiliary winding; and a correction unit that corrects the voltage output by the current detection unit to the control unit when the voltage induced in the auxiliary winding and detected by the first voltage detection unit is higher than a first predetermined value. This configuration can reduce start-up power consumption while suppressing the vibration noise of the transformer.