Parallel AC-DC Converters for Three-Phase Current Balance
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Solution Overview
Problem
Existing three-phase alternating-current power supply systems face instability and high energy consumption due to current unbalance between phases, leading to inefficient operation and increased heat generation.
Innovation Solution
A power supply apparatus with multiple AC-DC converters connected in parallel, a phase current detector, and a load current detector that dynamically switches converters based on current and load factor measurements to maintain balance, reducing or preventing current unbalance and optimizing power conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If converters are constantly driven to balance phase current, then current balance between phases is maintained, but electric power consumption increases and heat generation is increased
Solution Approach 1:
The patent implements dynamic switching of converter operation states based on real-time load conditions. The controller determines whether each converter should be in driven or stopped state according to actual power supply demand, transitioning from static constant driving to dynamic adaptive operation. This resolves the contradiction by making the system flexible rather than rigid, maintaining current balance only when necessary while reducing energy consumption when load is light.
Solution Approach 2:
The patent changes the operational parameters of converters from fixed constant driving to variable driving/stopped states based on load current detection. By detecting load current and adjusting converter operation states accordingly, the system adapts its parameters (driven/stopped) to match actual demand, thereby reducing unnecessary energy consumption while maintaining current balance when required.
2Use of energy by moving object
If converters are stopped during light load to reduce energy consumption, then electric power consumption decreases, but current balance between phases is lost and operation becomes unstable
Solution Approach 1:
The patent employs feedback control by detecting phase currents and load conditions, then using this information to determine converter operation states. The controller continuously monitors the system state and adjusts converter driving/stopped status based on feedback signals, ensuring current balance is maintained when necessary while allowing energy savings when load is light. This closed-loop feedback mechanism resolves the contradiction between energy saving and stability.
Solution Approach 2:
The patent performs preliminary detection of load current and phase current balance status before deciding converter operation states. By detecting conditions in advance and pre-determining the optimal converter configuration, the system avoids reactive adjustments that could cause instability, thereby maintaining both energy efficiency and operational stability.
3Power
If multiple converters are used to handle high load, then power supply capacity increases, but device complexity increases and control becomes more difficult
Solution Approach 1:
The patent divides the power supply system into multiple independent converters, each capable of operating autonomously. By segmenting the overall power supply function into separate converter units that can be independently controlled and switched, the system achieves high power capacity through parallel configuration while simplifying control through modular independence. Each converter can be individually managed based on load requirements, reducing overall system complexity.
Data Source
AI summary
A power supply apparatus includes converters connected in parallel to a three-phase alternating-current power supply, input current detectors that detect current flowing through the respective three phases of the three-phase alternating-current power supply, and load current detectors that detect load current of the converters. Each of the converters includes AC-DC converters inputs of connected to two of the three phases. The AC-DC converters are connected in parallel to each other using a common output. The AC-DC converters that are driven maintain balance of output current. A controller determines whether switching between a driven state and a stopped state of the respective AC-DC converters is performed based on detection results from the load current detectors and switches between the driven state and the stopped state of the respective multiple AC-DC converters based on detection results by the input current detectors.