Parallel Power Converter Control for Load-Adaptive DC Voltage
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Solution Overview
Problem
Existing power supply systems with parallel-connected power converters face issues of unbalanced output currents leading to instability, and require communication interfaces that increase device size and weight, while existing DC/DC converters struggle with variable load types.
Innovation Solution
A power supply system with parallel power conversion devices that includes a state detector, command generator, and voltage controller to generate droop characteristics, reducing load power consumption without communication, by adjusting voltage commands based on load states and sensor feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If communication interfaces are provided between power conversion devices to suppress output current unbalance, then output current balance is improved, but device size and weight increase
Solution Approach 1:
The patent extracts the communication function from the power conversion devices themselves and relocates it to a separate control device. The control device collects output current information from each power conversion device via simple interfaces, calculates unbalance, and generates correction signals, thereby eliminating the need for complex communication interfaces within each power conversion device while maintaining output current balance.
Solution Approach 2:
The patent introduces a separate control device as an intermediary between the power conversion devices. This control device acts as a mediator that receives data from all power conversion devices, performs the unbalance calculation and correction logic, and sends control signals back, thereby simplifying the interface requirements of individual power conversion devices.
2Adaptability or versatility
If DC voltage is output with flexible standards to match different load devices, then adaptability to loads is improved, but power consumption optimization becomes difficult when load kinds are not fixed
Solution Approach 1:
The patent implements dynamic voltage adjustment by continuously monitoring the operating states of connected loads and adjusting the DC voltage output accordingly. The control device detects load characteristics and dynamically optimizes the voltage level to minimize power consumption while ensuring compatibility with different load types, making the system both adaptable and energy-efficient.
Solution Approach 2:
The patent employs feedback mechanisms where the control device continuously monitors output current, voltage, and load operating states, then adjusts the voltage command in real-time based on this feedback. This closed-loop control enables the system to adapt to varying load types and optimize power consumption dynamically without requiring fixed voltage standards.
Data Source
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AI summary
A power supply system converts AC power from a main power source into DC power and outputs the DC power to a DC system (L). The power supply system includes a plurality of power conversion devices (10) connected in parallel with each other, a load state detector to detect an operating state of a load connected to the DC system (L), and a command generator (30) to generate a distribution voltage command Vref. Each of the power conversion devices (10) includes a DC voltage controller (212) to generate an output power command Pdc_ref based on a voltage of the DC system (L) and the distribution voltage command Vref, and an AC/DC converter (21) to convert AC power received from the main power source (2) based on the output power command Pdc_ref and output the converted power to the DC system (L). The command generator (30) generates the distribution voltage command Vref such that loss of the load connected to the DC system (L) is reduced, based on a detection result of the load state detector.