Parallel Converter Load Sharing via Auxiliary Compensation Voltage
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Solution Overview
Problem
Existing electrical DC/DC converters, when operated in open-loop with fixed modulation parameters, experience unequal current distribution among paralleled converters, leading to potential overloading and reduced output power due to variations in electric and thermal losses.
Innovation Solution
A method and controller that utilize auxiliary converters arranged in series with each electrical converter to balance load currents by adding compensation voltages, ensuring equal current distribution and preventing overloading through a controller that adjusts these voltages based on current differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If several electrical converters are operated in parallel to increase output power, then the available total output current and power are increased, but unequal current distribution occurs leading to overloading of some converters
Solution Approach 1:
The patent implements a feedback control mechanism where the controller continuously monitors the current through each electrical converter and adjusts the modulation parameter of converters with higher current to reduce the current difference. This closed-loop feedback ensures equal current distribution while maintaining high total output power from parallel-connected converters.
Solution Approach 2:
The patent dynamically adjusts the modulation parameter (such as pulse width or frequency) of individual electrical converters based on their current output. By changing this parameter in real-time according to measured current values, the system achieves balanced current distribution across parallel converters without requiring additional hardware complexity.
2Ease of operation
If electrical converters are operated in open-loop with fixed modulation parameters to simplify operation, then the control complexity is reduced, but current distribution cannot be influenced leading to unequal loading
Solution Approach 1:
The system performs self-balancing by automatically monitoring and adjusting individual converter currents without external intervention. Each converter essentially regulates itself through the controller's modulation parameter adjustments, maintaining equal loading while operating in what is effectively a simplified control mode that requires minimal external management.
Data Source
AI summary
An arrangement is described comprising first and second electrical converters arranged in parallel. First and second auxiliary converters are arranged in series with the first and second electrical converters, respectively. A method comprises receiving first and second values of currents through the first and second electrical converters respectively. A difference between the first and second values is determined and a first compensation voltage is determined therefrom. A second compensation voltage depending on the difference is determined and first and second signals are sent to first and second auxiliary converters respectively. The first auxiliary converter adds the first compensation voltage to a first voltage applied to the first electrical converter or to a first output voltage of the first electrical converter. The second auxiliary converter adds the second compensation voltage to the first voltage applied to the second electrical converter or to a second output voltage of the second electrical converter.