Harmonic Regulator Phase Compensation for AC Stability
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Solution Overview
Problem
Conventional harmonic regulators in AC electrical systems can become unstable due to drastic phase shifts, particularly around harmonic frequencies, leading to control system instability.
Innovation Solution
A harmonic regulator module that filters or cancels harmonic frequencies by shifting the phase angle at or near harmonic frequencies by a specific angle, such as 45 degrees, to prevent instability, using Laplace domain equations to define ideal and non-ideal outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a harmonic regulator is used to filter or cancel harmonic frequencies, then power quality is improved, but control system instability occurs due to drastic phase shifts around harmonic frequencies
Solution Approach 1:
The patent changes the phase angle parameter of the harmonic regulator output by introducing a phase shift θ. This modifies the regulator's frequency response to compensate for the drastic phase shifts that occur around harmonic frequencies, thereby maintaining control system stability while preserving the harmonic filtering function.
Solution Approach 2:
The patent introduces a phase compensation mechanism as an intermediary element between the harmonic regulator and the control system. This intermediary applies a corrective phase shift to the regulator output, mediating the destabilizing effect of natural phase shifts and preventing control system instability.
2Reliability
If phase angle is shifted at harmonic frequencies to prevent instability, then control system stability is improved, but phase accuracy may be compromised
Solution Approach 1:
The patent applies phase shift locally only at frequencies near the harmonic resonant frequency ω, rather than uniformly across all frequencies. The phase shift angle θ is specifically targeted to compensate for instability-prone regions while leaving other frequency regions unaffected, thus maintaining phase accuracy where it matters for stability without compromising overall phase precision.
Data Source
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AI summary
A harmonic regulator (101) for an AC power system can include a regulator module (103) configured to filter or cancel one or more harmonic frequencies of a fundamental frequency. The regulator module can be configured to inflect phase angle output about the one or more harmonic frequencies. The regulator module can be configured to shift phase at or near one or more harmonic frequencies by a shift angle (θ) to prevent primary regulator instability.