Distributed Control for Parallel DC Boost Converters
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Solution Overview
Problem
It is challenging to accurately apportion the power contribution of multiple DC power sources while maintaining a desired DC bus voltage, especially when the sources have varying time-varying characteristics and different dynamic behaviors.
Innovation Solution
A distributed control system is developed, featuring a central digital controller that computes optimal duty cycle settings for boost converters connected to a DC bus, utilizing PWM for power apportionment and load estimation through shared bus current and voltage measurements, enabling effective power management across disparate and time-varying DC power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a centralized controller is used to compute optimal duty cycle settings for power apportionment, then power distribution accuracy is improved, but system complexity increases
Solution Approach 1:
The control system is divided into multiple independent modules: a centralized controller for computation, individual boost converters for power conversion, and distributed sensors for measurements. Each module operates semi-independently, allowing the centralized controller to focus on optimization calculations while other components handle execution and local monitoring, thus resolving the complexity issue.
Solution Approach 2:
A communication network acts as an intermediary between the centralized controller and the distributed boost converters. This mediator transmits control signals and status information, enabling coordinated operation without requiring direct complex interconnections between all components, thereby managing system complexity while maintaining control accuracy.
2Adaptability or versatility
If distributed control with communication among controllers is implemented, then adaptability to time-varying loads is improved, but device complexity increases
Solution Approach 1:
Multiple distributed controllers are merged into a coordinated control system through the communication network. They share load information and synchronize their control actions, achieving unified adaptive response to time-varying loads while distributing the computational burden, thus improving adaptability without proportionally increasing complexity.
Solution Approach 2:
The system implements feedback mechanisms where controllers continuously monitor load conditions and power contributions, exchange this information through the communication network, and adjust duty cycle settings accordingly. This closed-loop feedback enables real-time adaptation to changing loads while maintaining manageable complexity through standardized feedback protocols.
3Adaptability or versatility
If PWM control is used for boost converters with different dynamic characteristics, then power transfer flexibility is improved, but control precision becomes more difficult to maintain
Solution Approach 1:
The control system dynamically adjusts PWM duty cycles for each boost converter based on real-time measurements of load conditions and source characteristics. The centralized controller computes time-varying duty cycle settings that adapt to the different dynamic characteristics of each converter, maintaining optimal power transfer while compensating for variations in dynamic response through continuous recalibration.
Data Source
AI summary
The disclosed invention is a distributed control system for operating a DC bus fed by disparate DC power sources that service a known or unknown load. The voltage sources vary in v-i characteristics and have time-varying, maximum supply capacities. Each source is connected to the bus via a boost converter, which may have different dynamic characteristics and power transfer capacities, but are controlled through PWM. The invention tracks the time-varying power sources and apportions their power contribution while maintaining the DC bus voltage within the specifications. A central digital controller solves the steady-state system for the optimal duty cycle settings that achieve a desired power supply apportionment scheme for a known or predictable DC load. A distributed networked control system is derived from the central system that utilizes communications among controllers to compute a shared estimate of the unknown time-varying load through shared bus current measurements and bus voltage measurements.