Power Supply Device with Preliminary Charging Circuit
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Solution Overview
Problem
Conventional power supply devices face issues with rush current, heat generation, and reduced power efficiency due to high current flow in rectifiers when the rated voltage of commercial AC power is low, and inability to perform zero-voltage switching when the voltage is high, leading to increased losses and restricted downsizing.
Innovation Solution
A power supply device with a switch and coil connected in series, using a current limiting element and rectifier for preliminary charging to suppress rush current, and performing boost rectification of the coil's voltage to charge the output smoothing capacitor, allowing zero-voltage switching and optimizing efficiency across varying input voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional rectifier and smoothing capacitor structure is used, then power factor improvement is achieved, but large rush current flows in the input smoothing capacitor or first rectifier when power is turned on
Solution Approach 1:
The patent applies preliminary action by introducing a preliminary charging circuit that charges the output smoothing capacitor before the main switching operation begins. This preliminary charging prevents large rush current by gradually establishing voltage on the capacitor prior to full power operation, thereby eliminating the harmful inrush current while maintaining the power factor improvement function.
2Adaptability or versatility
If rated voltage of commercial AC power source is low, then power supply operates, but supplied current to input smoothing capacitor is increased causing heat generation in first rectifier to increase and power efficiency to deteriorate
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the switching timing and resonance control parameters based on the input voltage level. When operating at low voltage, the control circuit modifies the switching frequency and timing to optimize current flow, thereby reducing heat generation in the rectifier and improving power efficiency while maintaining adaptability to low voltage conditions.
3Adaptability or versatility
If rated voltage of commercial AC power source is high, then power supply operates, but voltage across terminals of switching element does not become zero and zero-voltage switching cannot be performed resulting in deterioration of power efficiency
Solution Approach 1:
The patent applies dynamics by implementing dynamic resonance control that continuously adapts the switching timing based on the instantaneous voltage conditions. The control circuit monitors the voltage across the switching element and dynamically adjusts the switching moment to achieve zero-voltage switching even at high input voltages, thereby eliminating energy losses and improving power efficiency while maintaining operation capability across wide voltage ranges.
4Power
If conventional boost rectification circuit is used, then current flows through switching element and coil, but large rush current and heat generation restrict device downsizing
Solution Approach 1:
The patent applies preliminary action by pre-charging the output smoothing capacitor through a dedicated preliminary charging circuit before main power operation. This approach eliminates the need for oversized components that would otherwise be required to handle large rush currents and heat generation, enabling device downsizing while maintaining the boost rectification function.
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 suppresses rush current, maintains power efficiency at low voltages, and enables zero-voltage switching even at high input voltages, reducing losses and heat generation, thus improving the overall performance and reliability of the power supply device.
Implementation Method 1
a switching element and a coil cause the current to flow, and another second rectifier connected to an output terminal boosts and rectifies coil exciting current generated when the switch is turned off
Implementation Method 2
the input voltage is rectified by a first rectifier
Data Source
AI summary
A power supply device has a switch and a coil connected in series with alternating-current input power. A first rectifier connected across the coil performs boost rectification, and a voltage across an output smoothing capacitor is charged to obtain output power.