Reactive Power Compensator Offset Signal Control
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Solution Overview
Problem
Existing reactive power compensators face challenges in achieving uniform control with high reliability and stability, particularly due to complications in calculating zero-sequence voltage and current, which can lead to overshoot and transient voltage issues when external disturbances occur, affecting the system's ability to continuously operate.
Innovation Solution
A reactive power compensator system that includes phase clusters with a controller generating an offset signal through phasor transformation based on voltage and current values, compensating for energy errors between clusters using this offset signal, thereby ensuring uniform control and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If zero-sequence voltage or current is used for uniform control among clusters, then uniform energy control is achieved, but control becomes impossible or calculation becomes complicated when current is not supplied
Solution Approach 1:
The patent transforms the control parameter from zero-sequence voltage (which becomes undefined when current is zero) to active power and reactive power values, which remain calculable and meaningful even when current is not supplied. This parameter transformation resolves the contradiction by maintaining control capability across all operating conditions while avoiding calculation complications.
2Device complexity
If zero-sequence current is used for uniform control, then control calculation is simplified, but negative sequence component is not considered and reliability of uniform control is lowered
Solution Approach 1:
The patent segments the control approach by separately calculating active power and reactive power for each cluster, then using these segmented values to determine individual cluster command values. This segmentation allows consideration of both positive and negative sequence components through the power calculations, improving reliability while maintaining calculation simplicity through modular processing.
Solution Approach 2:
The patent implements dynamic adjustment of cluster command values based on real-time active power and reactive power measurements. The controller continuously monitors power values and dynamically modifies the command values to compensate for energy errors, ensuring reliable uniform control under varying operating conditions while keeping the control logic straightforward.
3Reliability
If zero-sequence voltage and current are calculated using error values among energies of clusters, then uniform control is achieved, but large overshoot or transient voltage is generated when external disturbance occurs
Solution Approach 1:
The patent applies beforehand cushioning by using active power and reactive power values as intermediate parameters that naturally smooth out disturbances. Instead of directly using error values that can cause large transient responses, the power-based approach provides a cushioning effect that attenuates overshoot and transient voltage when external disturbances occur, while still achieving uniform control through the offset signal generation.
Data Source
AI summary
A reactive power compensator includes a plurality of phase clusters each including plurality of cells and a controller configured to control the plurality of phase clusters. The controller performs control to generate an offset signal through phasor transformation based on respective voltage values and current values of the plurality of phase clusters and to compensate for energy errors between the plurality of phase clusters based on the generated offset signal.