DC Power Converter Control Updates for Stable Bus Voltage
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Solution Overview
Problem
In a DC grid with decentralized power converters, unintended voltage fluctuations can occur due to delayed communication updates in control methods, leading to unintentional increases or decreases in bus voltage when changing feedback control from voltage to power or vice versa.
Innovation Solution
Implement a method where power converters update their control methods in a synchronized manner, ensuring that at least one converter always performs droop V control to stabilize bus voltage, by using a centralized controller to manage updates and ensure timely execution of control changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If decentralized feedback control is implemented in power converters, then autonomy and adaptability are improved, but voltage stability deteriorates when communication delays occur during control method updates
Solution Approach 1:
The patent applies preliminary action by having the centralized controller coordinate control method updates across all power converters before actual switching occurs. The controller sends update instructions to each converter, ensuring they all prepare for the transition simultaneously, thus preventing voltage instability during the switching process while maintaining decentralized autonomous operation.
2Ease of operation
If centralized control is used to manage power converters, then ease of operation is improved, but responsiveness to rapid power supply and demand changes deteriorates
Solution Approach 1:
The patent segments the control function into two parts: centralized coordination for control method updates (handled by the centralized controller) and decentralized real-time power regulation (handled by individual power converters using local feedback). This segmentation allows the centralized controller to manage overall stability while converters respond rapidly to local power supply and demand changes without waiting for centralized instructions.
3Adaptability or versatility
If control method updates are performed in power converters, then adaptability is improved, but voltage stability deteriorates due to communication delays causing asynchronous switching
Solution Approach 1:
The patent uses feedback mechanisms where the centralized controller monitors the status of control method updates across all power converters and coordinates subsequent updates based on this feedback. The controller waits for confirmation that converters have successfully updated before initiating the next control method change, ensuring synchronous switching and preventing voltage instability caused by communication delays.
Data Source
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AI summary
A power system includes a plurality of power converters including a power conversion unit that converts a power that is input and outputs the converted power, a controller that controls the power conversion unit and executes control on the output that is primary control based on a reference function having a drooping characteristic defined according to an input value and a voltage or a power of a bus to which the power conversion unit is connected, and an update unit that updates a control method on the output; and a central control device that executes secondary control of controlling the power converter, wherein the central control device performs the secondary control on the power converter according to an update instruction to update the control method, and the update unit updates the control method according to the update instruction that is output from the central control device and updates the control method such that there is always at least one of the power converters that performs voltage control in a period in which the power converters update the control method.