Parallel Converter Current Balancing via Individual Correction
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Solution Overview
Problem
Existing multi-phase DC-to-DC converters face challenges in accurately correcting variations in output currents among parallel-connected converters due to component performance variations, leading to reduced converter lifetime under high load conditions.
Innovation Solution
A switching power supply apparatus with two converters connected in parallel, each equipped with an output current detector, controller for PWM control, and correction mechanisms that allow for individual correction of output currents by transmitting and receiving correction values externally, enabling precise balancing of output currents without requiring design adjustments for variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correction values are calculated and stored in memory before shipping, then variations in detection results can be corrected, but the same correction value is used for all converters which prevents separate correction of individual converter variations
Solution Approach 1:
The patent divides the correction system into separate correction values for each converter (first correction value for first converter, second correction value for second converter). Each current detection circuit has its own dedicated correction value stored in memory, allowing independent correction of detection variations for each converter without affecting others.
Solution Approach 2:
The patent applies different correction values to different converters based on their individual detection circuit characteristics. Each converter's detection circuit receives a tailored correction value that specifically addresses its own variations, rather than applying a uniform correction to all converters.
2Reliability
If multiple current detection circuits are provided for parallel converters, then individual current monitoring is enabled, but component performance variations cause detection results to vary requiring complex correction mechanisms
Solution Approach 1:
The patent performs correction value calculation and storage in memory before the converters are shipped from the factory. Detection results from each current detection circuit are obtained in advance, and corresponding correction values are calculated and stored. During actual operation, these pre-calculated correction values are applied to correct detection results, eliminating the need for complex real-time correction mechanisms.
3Power
If converters are connected in parallel to increase total output power, then power capacity is improved, but unbalanced output currents cause high load factors that shorten converter lifetime
Solution Approach 1:
The patent implements a feedback control mechanism where detection results from each current detection circuit are corrected using stored correction values, and the corrected results are used to control the parallel-connected converters. This ensures that output currents remain balanced even when converters operate at high load factors, preventing premature failure and extending converter lifetime while maintaining increased power output.
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 configuration allows for accurate correction of output current variations in each converter, reducing the size of the power supply apparatus and eliminating the need for design accommodations for variations, thereby enhancing reliability and efficiency.
Implementation Method 1
a first PWM controller that performs PWM control on the first converter so as to make the magnitude of the output current, which is detected by the first output current detector, and the current target value which is generated by the current target value generator be equal or substantially equal to each other
Data Source
AI summary
In a switching power supply apparatus, a magnitude of an output current of a first converter, which has been detected in a state in which a second converter is stopped, is transmitted to a measurement tool and a magnitude of an output current of the second converter, which has been detected in a state in which the first converter is stopped, is transmitted to the measurement tool. Correction values determined by the measurement tool based on transmission contents are received and stored in a memory. A magnitude of the output current which is used for PWM control of the first converter and a magnitude of the output current which is used for PWM control of the second converter are respectively corrected with the correction values.