Interconnected Power Supply Duty Cycle Control via Average Voltage
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Solution Overview
Problem
Existing systems for controlling interconnected power supplies face challenges in ensuring uniform charging and discharging of individual power supplies, often requiring a master controller or peer-to-peer communication, and struggle to manage differences in output currents among interconnected power converters.
Innovation Solution
A method and system where each power supply includes a switching power converter circuit and a controller that determines a control signal based on the storage voltage, average storage voltage, and reference voltage to regulate the duty cycle, allowing interconnected power supplies to share loads and energy uniformly without a master controller, using a common electrical node with resistive elements to calculate average voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a master controller or peer-to-peer communication is used to control interconnected power supplies, then uniform charging and discharging can be achieved, but the device complexity increases
Solution Approach 1:
Each power supply unit autonomously determines its duty cycle based on locally measured storage voltage and average storage voltage, without requiring external control signals from a master controller or communication with other units. The system achieves uniform power sharing through self-service control where each unit independently adjusts its operation
Solution Approach 2:
A common electrical node with resistive elements serves as an intermediary that automatically generates the average storage voltage signal from all connected power supplies. This passive intermediary eliminates the need for active communication infrastructure while enabling each controller to receive the necessary average voltage information for uniform power sharing
2Productivity
If conventional voltage mode control with democratic sharing is used, then power sharing can be achieved, but the system cannot effectively manage differences in output currents among interconnected power converters
Solution Approach 1:
The control method changes from voltage-mode control to a method that directly controls duty cycle based on storage voltage measurements. By determining duty cycle as a function of storage voltage and average storage voltage, the system adapts to different power converter ratings and output current capabilities without requiring complex current balancing mechanisms
Solution Approach 2:
The control approach segments the power sharing problem into individual unit control, where each power supply independently determines its duty cycle based on its own storage voltage and the common average storage voltage. This segmentation allows each unit to operate within its capabilities while contributing to overall system power sharing
Data Source
AI summary
In an electrical power supply having a plurality of switching power converter circuits and configured to supply a voltage to an electrical load, a method of controlling a duty cycle of at least one switch of one of the plurality of switching power converter circuits includes determining a storage voltage produced by the one of the plurality of energy storage devices. The method further includes determining an average storage voltage corresponding to an average of storage voltages produced by each of the plurality of energy storage devices. The method further includes determining at least one control signal as a function of the storage voltage, the average storage voltage, and a reference voltage. The method further includes controlling the duty cycle of the at least one switch of the one of the plurality of switching power converter circuits based upon the at least one control signal.