Inverter Control Switching Using GFL-to-GFM Initial Value Alignment
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Solution Overview
Problem
Existing inverter power supplies face challenges in smoothly transitioning between grid forming (GFM) and grid following (GFL) control modes, leading to sudden fluctuations in output voltage during mode switching.
Innovation Solution
A power conversion device with integrated GFM and GFL controllers, including an initial value adjusting circuit, that uses switching signals to initiate GFM control with initial values from GFL control, reducing sudden voltage fluctuations by setting GFL command values as initial values for GFM control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If grid following control is switched to grid forming control, then the inverter power supply can operate in different control modes to adapt to different use situations, but sudden fluctuations in output voltage occur leading to instability
Solution Approach 1:
The patent applies preliminary action by setting the initial values of the amplitude command value and phase command value in grid forming control to match the actual values from grid following control before switching occurs. This pre-alignment of parameters prevents sudden voltage fluctuations when transitioning between control modes, thereby maintaining output voltage stability while enabling versatile operation.
2Adaptability or versatility
If grid following control is switched to grid forming control, then the inverter power supply can adapt to different use situations, but sudden fluctuations occur reducing reliability
Solution Approach 1:
The patent applies preliminary action by pre-setting the initial values of amplitude and phase command values in grid forming control to match the actual values from grid following control before switching. This ensures a smooth transition without sudden fluctuations, maintaining reliable operation while enabling flexible adaptation to different use situations.
3Speed
If direct switching from grid following control to grid forming control is performed, then control mode transition is simple and fast, but output voltage fluctuations occur
Solution Approach 1:
The patent applies preliminary action by pre-configuring the initial values of amplitude and phase command values in grid forming control to match the actual values from grid following control before switching occurs. This allows for fast switching response while preventing output voltage fluctuations through the pre-alignment of control parameters.
Data Source
AI summary
A power conversion device is disclosed in which a grid following amplitude command value and a grid following phase command value are output in response to receiving a switching signal instructing switching from grid following control to grid forming control. The grid following amplitude command value indicates a target value of an amplitude computed by the grid following control. The grid following phase command value indicates a target value of a phase computed by the grid following control. When the grid following control is switched to the grid forming control, an initial value of the target value of the amplitude in the grid forming control to be the grid following amplitude command value is set, and an initial value of the target value of the phase in the grid forming control to be the grid following phase command value is set.