Microgrid Power Converter Voltage Control via FPGA Feedback
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Solution Overview
Problem
Microgrid power converters face instability and lack of flexibility when changes in current or voltage occur, leading to potential system shut-off and damage due to limitations in control modes such as constant power control.
Innovation Solution
The control software adjusts commanded current values based on deviations in measured output voltage to stabilize voltage output, particularly advantageous in microgrid implementations where voltage noise is a concern, using a power-packet-switching architecture with bidirectional switches and a Field Programmable Gate Array (FPGA) controller to manage switch operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If constant power control mode is used in microgrid power converters, then power transfer efficiency is maintained, but system stability deteriorates when voltage or current changes occur
Solution Approach 1:
The patent implements dynamic control mode switching capability that allows the power converter to transition between constant power control mode and other control modes (such as constant voltage or constant current modes) based on real-time system conditions. This dynamic adaptability resolves the contradiction by enabling the system to maintain power transfer efficiency when stable while switching to alternative modes when instability is detected, thus preventing system shutdown or damage.
2Adaptability or versatility
If standalone operation mode is used in microgrid converters, then independence from utility grid is achieved, but voltage stability control becomes more difficult
Solution Approach 1:
The patent incorporates feedback control mechanisms that continuously monitor output voltage and current in standalone operation mode. The control system uses this feedback information to dynamically adjust switching commands and control parameters, enabling effective voltage stability control independent of the utility grid. The feedback loop allows the converter to detect and correct voltage deviations in real-time, resolving the control difficulty associated with standalone operation.
3Loss of energy
If power-packet-switching architecture is used, then conversion efficiency is improved, but control complexity increases
Solution Approach 1:
The patent implements a universal control framework that can operate in multiple modes (constant power, constant voltage, constant current) and support both grid-tied and standalone operations using the same power-packet-switching hardware architecture. This multi-functionality reduces control complexity by providing a unified control structure that adapts to different operating conditions rather than requiring separate specialized control systems for each mode or application.
Data Source
AI summary
Methods and systems for controlling voltage output in power converters between two or more portals, where any or all portals can be DC, single phase AC, or multi-phase AC. The present methods involve determining a reference output voltage VI, measuring the output voltage VE over a power cycle, comparing VI to VE to calculate a delta voltage ΔV. ΔV can then be multiplied by a scaling parameter k to determine a current command IE. IE can then be used by a current control module in a power converter to control output current. The present methods can be implemented as an algorithm embedded in an FPGA controller connected to the power converter.