Inverter Voltage Control Using Fuzzy Feedback Instead of Droop
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Solution Overview
Problem
The droop control method for inverter output voltage control in rail transit power supply systems results in poor accuracy and robustness, leading to voltage fluctuations as power changes.
Innovation Solution
A method and system utilizing a fuzzy controller and PI controllers to adjust the amplitude and phase of the inverter output voltage, determining a target voltage based on current voltage errors, and adjusting the output voltage to maintain it within a preset range, eliminating the need for droop control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If droop control method is used to control inverter output voltage, then power sharing accuracy is improved, but output voltage accuracy is degraded
Solution Approach 1:
The patent implements a closed-loop feedback control system that continuously monitors the actual output voltage of each inverter and compares it with the reference voltage. Based on the voltage deviation feedback, the controller dynamically adjusts the inverter output to maintain accurate voltage levels, thereby resolving the contradiction between power sharing accuracy and output voltage accuracy by actively compensating for voltage droop effects.
2Ease of operation
If droop control method is used to control inverter output voltage, then power sharing is achieved, but robustness is degraded
Solution Approach 1:
The closed-loop feedback mechanism continuously detects voltage deviations and automatically adjusts inverter outputs to maintain stable voltage levels under varying load conditions. This feedback-based approach enhances system robustness by compensating for disturbances and parameter variations, while still achieving effective power sharing among parallel inverters.
3Power
If droop control method is used, then output power control is achieved, but output voltage stability is degraded
Solution Approach 1:
The patent employs voltage feedback control that continuously monitors actual output voltage and adjusts the inverter control signals to maintain voltage stability. This feedback mechanism decouples the relationship between power output and voltage stability by actively regulating voltage levels regardless of power variations, thereby resolving the contradiction between output power control capability and voltage stability.
4Productivity
If droop control method is used, then power sharing control is realized, but voltage accuracy is degraded
Solution Approach 1:
The closed-loop feedback control system simultaneously achieves power sharing and voltage accuracy by monitoring actual voltage outputs and dynamically adjusting inverter control parameters. The feedback mechanism ensures that each inverter contributes to power sharing while maintaining its output voltage within accurate tolerances, resolving the contradiction between power sharing control and voltage accuracy.
Data Source
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AI summary
Provided are a voltage control method and system. The method comprises: calculating the current voltage error between a given output voltage and the current output voltage; inputting the current voltage error into a fuzzy controller, and determining a target output voltage of an inverter; on the basis of the amplitude difference and the phase difference between the target output voltage and the current output voltage, determining an amplitude adjustment instruction using a first PI controller, and determining a phase adjustment instruction using a second PI controller; and adjusting the amplitude of the output voltage of the inverter according to the amplitude adjustment instruction, and adjusting the phase of the output voltage of the inverter according to the phase adjustment instruction, such that the output voltage of the inverter is kept within a pre-set range. In the solution, a fuzzy controller is used to determine a target output voltage of an inverter, and the amplitude and phase of the output voltage of the inverter are adjusted according to the target output voltage and PI controllers, such that the output voltage of the inverter is kept within a pre-set range. There is no need to perform droop control on the output voltage of the inverter, thereby improving the precision and robustness of the output voltage.