Power Quality Compensator Ripple Prediction Control
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Solution Overview
Problem
Conventional power quality compensators, such as APF and SVG, face issues with low response speed and voltage fluctuations due to their low-bandwidth voltage control loops, which can lead to bus voltage instability and damage to connected electronic devices.
Innovation Solution
A power quality compensator device and control method that includes a current controller, converter, ripple predictor, processing unit, and voltage controller, which predicts and compensates the ripple component of the bus voltage using an intermediate voltage and current, allowing for a higher bandwidth voltage control loop and improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a low-bandwidth voltage outer loop is used to ensure average bus voltage stability, then voltage stability is improved, but the response speed becomes slower
Solution Approach 1:
The patent predicts the ripple voltage in advance using a ripple predictor that calculates expected voltage fluctuations based on switching signals and circuit parameters. This preliminary prediction allows the system to prepare compensation actions before the actual ripple occurs, improving response speed without compromising stability
Solution Approach 2:
The patent creates a virtual model of the voltage ripple through the ripple predictor that replicates the expected voltage fluctuations. This virtual copy allows the control system to analyze and compensate for ripple effects without being constrained by the slow response of traditional low-bandwidth voltage loops
2Stability of the object's composition
If a low-bandwidth voltage outer loop is used, then voltage stability is improved, but voltage fluctuation increases
Solution Approach 1:
The patent introduces a ripple predictor as an intermediary component that sits between the voltage controller and the power quality compensator. This intermediary predicts voltage ripple and provides compensation signals that counteract the fluctuations, allowing the system to maintain stability while reducing harmful voltage variations
Solution Approach 2:
The patent replaces the traditional mechanical voltage sampling and low-pass filtering approach with a predictive mathematical model. Instead of physically measuring and filtering voltage signals, the system uses computational prediction to estimate and compensate for ripple, achieving faster response and reduced fluctuation
3Stability of the object's composition
If a low-bandwidth voltage outer loop is used, then voltage stability is improved, but the fluctuation exceeds protection threshold
Solution Approach 1:
By predicting voltage ripple in advance, the system can take preliminary compensation actions before the voltage fluctuation exceeds protection thresholds. This proactive approach ensures that voltage remains within safe limits while maintaining overall stability
Data Source
AI summary
A power quality compensator device and a control method thereof are provided. The power quality compensator device is electrically connected to a power grid and a nonlinear load, and includes a current controller, a converter, a ripple predictor, a processing unit and a voltage controller. The current controller is configured to receive an instruction current and output a switch control signal. The converter is configured to output an output current and an actual DC bus voltage according to the switch control signal. The ripple predictor is configured to receive an intermediate voltage and a first current and output a predicted ripple voltage. The processing unit is configured to output a processing result according to the actual DC bus voltage, the predicted ripple voltage and a reference DC bus voltage. The voltage controller is configured to receive the processing result and output a voltage control signal to the current controller.