I've seen a wide range of L and C values for LC filters for off-grid inverters in papers. Is it true to say that less inductance and larger capacitance must be chosen for high power inverters? Large capacitors have large reactive power and current but a large inductance has a big size. How should we choose LC values?
Design Considerations:
1. Resonant Frequency. Any LC circuit will have a resonant frequency, fo=1/(2*pi*sqrt(LC))
2. Power Factor: Capacitors provide negative reactive power (VARs) and a leading power factor whereas inductors provide positive reactive power (VARs) and a lagging power factor.
3. Waveform rise and decay time: Inductors can change the rise-time of a waveform (approximately L/R) whereas capacitors can change the decay time (C*R). Larger capacitors provide more energy thus extending the decay time.
4. Cost: if I am not mistaken, inductors are more expensive than capacitors?
Thanks for your answer. But I need more exact solutions. for example, for a 50Hz off-grid system, How should we choose the resonant frequency?
In some cases, large capacitors are expensive as well and their reactive current occupies the capacity of transformers.
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