Series-Parallel DC Power Supply Alternating Converter Units
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Solution Overview
Problem
Conventional DC power supply equipment faces challenges in reducing fixed losses and minimizing size and cost due to the increased number of isolated DC-DC converters, particularly in light load conditions, where inefficiencies arise from resistive losses and iron losses in transformers.
Innovation Solution
The equipment connects DC input sides of multiple isolated DC-DC converter units in series and controls them to operate alternately in a predetermined time ratio during light loads, reducing the number of active converters and minimizing dead space and component costs, while using capacitors to absorb current and voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple isolated DC-DC converters are connected in parallel to achieve high power capacity, then the power supply capacity is improved, but the fixed losses (resistive losses and iron losses) increase
Solution Approach 1:
The patent implements periodic action by alternately operating multiple isolated DC-DC converter units in a predetermined time ratio during light load conditions. This allows the system to maintain high power capacity through multiple units while reducing fixed losses by activating only one unit at a time during low-demand periods, thus eliminating unnecessary resistive and iron losses in inactive units
Solution Approach 2:
The system dynamically adjusts the operation state of converter units based on load conditions. During light loads, units are alternately activated; during heavy loads, multiple units operate simultaneously. This dynamic control optimizes the balance between power supply capacity and fixed losses, allowing the system to adapt its configuration to actual operational requirements
2Power
If multiple isolated DC-DC converter units are used to achieve high power capacity, then the power supply capacity is improved, but the device size and cost increase
Solution Approach 1:
The patent merges multiple isolated DC-DC converter units into a single integrated power supply system with common input and output connections. By connecting DC input sides in series and output sides in parallel, the system achieves high power capacity while sharing common components (input capacitors, output capacitors, control circuits), thereby reducing overall device size and cost compared to completely separate converter units
3Strength
If semiconductor switching devices with high withstand voltage are used to handle high DC input voltage, then the voltage handling capability is improved, but the switching frequency decreases
Solution Approach 1:
The patent segments the high voltage DC input into multiple lower voltage sections by connecting DC input sides of converter units in series. Each converter unit handles a portion of the total voltage, allowing the use of semiconductor switching devices with lower withstand voltage ratings that can operate at higher switching frequencies, thus resolving the trade-off between voltage handling and switching speed
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
This approach reduces fixed losses, maintains efficiency, and minimizes the overall size and cost of the DC power supply equipment by reducing the number of converters and balancing capacitor voltages, ensuring stable operation across varying load conditions.
Implementation Method 1
the inverter 31a converts once a DC voltage into a high frequency AC voltage
Implementation Method 2
the transformer 32a isolates and transforms the AC voltage
Implementation Method 3
the rectifier circuit 33a rectifies the AC voltage to convert again into a DC voltage
Implementation Method 4
using capacitors to absorb current and voltage variations
Data Source
AI summary
A power supply equipment includes a plurality of units each including a capacitor and an isolated DC-DC converter connected between the both terminals of the capacitor, wherein DC input sides of the plurality of units are connected in series and the DC output sides are connected together in parallel. The DC power supply equipment also comprises control circuits to control the isolated DC-DC converters. The control circuits generate operation commands to operate some of the plurality of units in an alternating sequence with a same time ratio in a predetermined control period in a light load condition, and the control circuits control the isolated DC-DC converters of the units according to the operation command.