Image Forming Power Supply Switching to Suppress Inrush Current
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Solution Overview
Problem
Existing power supply systems in image forming apparatuses face issues with inrush currents and repetitive on/off operations due to intermittent oscillation, leading to potential malfunctions and increased costs when switching between high and low voltage modes.
Innovation Solution
A power supply apparatus with a first generation unit that performs intermittent oscillation in a low power mode, a switching unit that turns on only when the voltage is outside a predetermined range, and a control unit that ensures mode transitions occur after the switching unit is in the ON state, thereby preventing repetitive on/off operations and suppressing inrush currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the switching unit is configured to have a large current rating to withstand inrush current, then the reliability is improved, but the cost increases
Solution Approach 1:
The switching unit is turned on in advance while the first generation unit is still operating in the second (low voltage) mode, before the mode switch to the first (high voltage) mode occurs. This preliminary action ensures that when the high voltage is applied, the switching unit is already in the ON state, avoiding large inrush current and allowing the use of lower current rating components, thus reducing cost while maintaining reliability
2Use of energy by moving object
If the single-converter system operates in low power consumption mode with intermittent oscillation, then the energy efficiency is improved, but the stability deteriorates due to voltage fluctuation causing repetitive on/off operations
Solution Approach 1:
The switching unit is turned on in advance during the intermittent oscillation operation in the second mode, before the voltage stabilizes to the first mode level. This preliminary action ensures that when the mode transition occurs and voltage fluctuations happen, the switching unit remains in the ON state and does not undergo repetitive on/off operations, thus maintaining stability while preserving the energy efficiency benefits of intermittent oscillation
Data Source
AI summary
A power supply apparatus includes a first power supply unit configured to operate in a first mode in which a first DC voltage is generated or in a second mode in which a second DC voltage lower than the first DC voltage is generated. The first power supply unit performs an intermittent oscillation operation when operating in the second mode. The second DC voltage changes within a predetermined range due to the intermittent oscillation operation. A switch is connected between the first and second power supply units and serves to turn on and off the supply of the first or second DC voltage to a load. A controller performs control such that when the first power supply unit is switched from the second mode to the first mode, the switching from the second mode to the first mode is performed after the switch is turned on to the ON state.