Parallel DC Power Supply Load Balancing via Temperature Feedback
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Solution Overview
Problem
Conventional load sharing techniques for parallel DC-DC converters often result in unequal current distribution due to slight differences in output voltages and component values, leading to thermal stress and inefficiencies, especially when additional wiring or complex control circuits are required.
Innovation Solution
A temperature-based control method using a thermistor in the feedback loop of each converter module to adjust output voltage based on temperature measurements, ensuring balanced current sharing among modules without additional wiring, by reducing output voltage as temperature increases, thus distributing load more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional load sharing techniques are used for parallel DC-DC converters, then current distribution is attempted to be balanced, but unequal current distribution occurs due to slight differences in output voltages and component values, leading to thermal stress and inefficiencies
Solution Approach 1:
The patent implements a feedback mechanism where the output voltage of each converter module is fed back to a control circuit that adjusts the duty cycle of the switching device. This closed-loop feedback system continuously monitors and corrects voltage deviations, ensuring equal current sharing among parallel modules and preventing thermal stress caused by unequal load distribution.
Solution Approach 2:
The patent dynamically adjusts the duty cycle parameter of the switching device based on feedback from voltage sensing circuits. By changing this control parameter in real-time, the system compensates for component variations and maintains balanced current distribution, thereby reducing thermal stress on individual modules.
2Reliability
If additional wiring or complex control circuits are added to achieve balanced current sharing, then current distribution improves, but device complexity and cost increase
Solution Approach 1:
The patent combines the load sharing control function with the existing output voltage feedback circuitry of each converter module. By merging these functions, the system achieves balanced current sharing without requiring separate dedicated control circuits or additional wiring between modules, thus maintaining simplicity while improving reliability.
Solution Approach 2:
Each converter module independently performs voltage sensing and duty cycle adjustment using its own integrated control circuit. The modules self-regulate their output based on local feedback, eliminating the need for complex centralized control or inter-module communication wiring, thereby reducing overall system complexity.
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 achieves balanced current sharing among parallel converter modules, reduces thermal stress, and eliminates the need for extra connections, allowing for more efficient and cost-effective operation while maintaining stable output voltages across varying temperatures.
Implementation Method 1
measuring the temperature of a thermistor coupled to a converter module
Implementation Method 2
applying a DC voltage across an inductor or transformer for a period of time which causes current to flow through it and store energy magnetically, then switching this voltage off and causing the stored energy to be transferred to the voltage output
Data Source
AI summary
A system and a method are provided that allow load sharing between two or more DC output power supplies that are connected in parallel to scale the output power. As the temperature of the critical components in a power supply rises, the output voltage from that power supply will be lowered, so that the coolest supply will have the highest voltage and thus the highest current to the load. The systems and methods can operate without any additional wires connecting the supplies other than those supplying the power to the load.