Parallel Current-Sharing Control Without Bus
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Solution Overview
Problem
Conventional parallel current-sharing methods for high-power switching power supplies require a current-sharing bus, leading to slow system response, poor anti-interference capability, and complex circuit design due to bidirectional signal transmission and ground wire loop currents, limiting their flexibility and application range.
Innovation Solution
A parallel current-sharing control method without a current-sharing bus, where a voltage control module and power conversion submodules form an outer voltage loop, with inner current loops sampling feedback signals to generate control signals that are superposed with the outer voltage loop signal for controlling outputs, enabling unidirectional differential signal transmission and eliminating the need for an independent current bus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current-sharing bus is used for parallel current-sharing control, then current sharing can be achieved, but the system response becomes slower and the circuit complexity increases
Solution Approach 1:
The patent extracts the current-sharing function from the traditional current bus architecture. Each module independently compares its own current feedback with a reference voltage and generates its own control signal, eliminating the need for a shared current bus that connects all modules. This extraction of the current-sharing function from the bus architecture enables faster response while maintaining current sharing capability.
Solution Approach 2:
The patent segments the centralized current-sharing control into distributed independent control units. Each power conversion module has its own current comparison and control circuitry, allowing parallel and independent operation of multiple modules without serial connection delays. This segmentation removes the bottleneck of centralized control and enables simultaneous response of all modules.
2Reliability
If bidirectional signal transmission is implemented in the current bus, then current sharing control is achieved, but the anti-interference capability deteriorates due to ground wire loop currents
Solution Approach 1:
The patent removes the bidirectional signal transmission requirement by extracting the current-sharing control function from the data bus. Instead of transmitting control signals bidirectionally through a shared bus, each module independently generates its control signals based on local current feedback comparison, eliminating ground wire loop currents and improving anti-interference capability.
3Reliability
If multiple control buses are used for remote voltage compensation and module current equalization, then voltage regulation and current sharing are improved, but the device complexity and fault rate increase
Solution Approach 1:
The patent merges the voltage regulation and current sharing control functions into a unified distributed control architecture. The outer voltage loop and inner current loop are integrated within each module, with the voltage control module generating reference signals that are simultaneously used for both voltage regulation and current equalization. This merging eliminates the need for separate control buses and reduces system complexity.
Solution Approach 2:
The voltage control module serves multiple functions: it generates the voltage regulation control signal, provides the current reference for current sharing, and enables both remote voltage compensation and module current equalization through a single integrated control path. This multi-functionality reduces the number of required control buses and simplifies the overall system architecture.
Data Source
AI summary
The present invention provides a parallel current-sharing device and control method without a current-sharing bus, for implementing parallel current sharing of direct-current outputs of a plurality of power conversion submodules. The parallel current-sharing device comprises a voltage control module and a plurality of power conversion submodules. The voltage control module and the plurality of power conversion submodules having parallel outputs form an outer voltage loop. The power conversion submodules comprise respective inner current loops and sample respective current feedback signals to generate inner current loop control signals, and the inner current loop control signals are superposed with an outer voltage loop control signal to control output of the power conversion submodules. An independent current bus is not required, and only one unidirectional outer control voltage loop is required. Functions the same as those of a conventional device are realized; the design, production and debugging of circuits of the parallel current-sharing device are simpler; a rapid multi-parallel dynamic response is realized; a ground wire loop current is eliminated, improving the anti-interference capability of the device; and multi-module parallel current sharing of a switching power supply or a linear power supply under analog control or digital control is realized very easily.