The general function of the ldo controller is to prevent changes in current, which is achieved by converting electrical energy into magnetic energy for storage. The current classification is also relatively rich, there are parallel, series, tuning, current limiting, damping and other types, each type has its corresponding role and value. It is necessary to understand the reactance k value of ldo controller, which is related to the selection and use of ldo controller, below we ldo controller manufacturers to share for you!
1, if the harmonic content in the system is small, and only the limited closing surge current is considered, k=(0.5~1)% can meet the standard requirements. However, the ldo controller will heavily amplify the 5th harmonic current and slightly amplify the 3rd harmonic current.
2, if the harmonics in the system can not be ignored, you should find out the background harmonic content of the power supply system, and then reasonably determine the K value. In order to achieve the purpose of harmonic reduction, the inductive harmonic impedance should be configured at the capacitor access.
① When the background harmonic of the system grid is 5 times or more, the reactance rate should be configured as (4.5~6)%. The overall situation of the power grid is: the 5th harmonic to the largest, the 7th harmonic to the second, the 3rd harmonic to the smallest. Therefore, this project selected more reactors with k=4.5%~6%, which are widely used in the world.
② The configuration of 6%ldo controller has a good effect on reducing the 5th harmonic, but has an obvious amplification effect on the 3rd harmonic. Its resonance point (204hz) is far away from the fifth harmonic frequency (250Hz), and the margin is large.
③ 4.5%ldo controller is configured to slightly amplify third harmonics. Therefore, the fifth and above harmonics are appropriately weakened, while the amplification of the third harmonics is reduced. However, the frequency distance between the resonant point (235hz) and the 5th harmonic is small.
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