Distributed Current Balancing Control for Parallel Power Converters
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Solution Overview
Problem
Existing power converter systems face challenges with circulating currents when multiple power converters are connected in parallel, leading to inefficiencies and potential damage due to differences in circuit impedances and gate driver propagation times, which existing centralized control solutions fail to adequately address without increasing weight and complexity.
Innovation Solution
Incorporating first and second feedback circuits within each power converter to modulate output voltages and currents, reducing circulating currents by adjusting gains and modulation schemes to balance positive and zero sequence currents, thereby minimizing circulating currents without the need for centralized control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple power converters are connected in parallel to power loads, then the power requirement range is expanded and drive availability is increased, but circulating currents are generated due to differences in circuit impedances and gate driver propagation times
Solution Approach 1:
The patent implements a feedback control mechanism where the control unit monitors the output currents of parallel-connected power converters and adjusts their operation to minimize circulating currents. The feedback signal is derived from the difference between the sum of output currents and a reference current, enabling continuous correction of current imbalances caused by impedance variations and propagation time differences.
Solution Approach 2:
The patent modifies operating parameters of the power converters dynamically. The control unit adjusts the switching timing and duty cycles of individual power converters based on real-time current measurements, changing parameters such as gate driver propagation times and circuit impedance characteristics to reduce circulating currents while maintaining the ability to meet varying power requirements.
2Object-generated harmful factors
If centralized control solutions are used to manage parallel power converters, then circulating currents can be reduced, but system weight and complexity increase
Solution Approach 1:
The patent divides the control function into distributed segments, with each power converter equipped with its own control unit that operates semi-independently. Each control unit processes local current measurements and adjusts its own converter's operation, eliminating the need for a heavy centralized control system while still achieving circulating current reduction through coordinated operation of all converters.
Solution Approach 2:
Each power converter is equipped with self-regulating capabilities through its own control unit that autonomously adjusts its operation based on system conditions. The converters perform self-diagnosis and self-correction of current imbalances, reducing the need for external centralized control infrastructure and thereby reducing overall system complexity and weight.
Data Source
AI summary
A power converter for providing power to one or more loads, wherein the power converter is configured to be arranged in a parallel configuration with one or more additional power converters. The power converter comprises an inverter for receiving an input voltage and converting this to an output voltage having an associated output current, a module configured to modulate the output voltage using a modulation scheme and first and second feedback circuits.