Harmonic Filter Calculator — 公式
## Single-Tuned Harmonic Filter Design
A series LC filter tuned to a specific harmonic frequency provides a low-impedance path that diverts harmonic current away from the system.
### Design Steps
1. **Capacitive reactance at fundamental**: Xc = V^2 / kVAR
2. **Inductive reactance at fundamental**: Xl = Xc / n^2
3. **Capacitance**: C = 1 / (omega x Xc)
4. **Inductance**: L = Xl / omega
Where n is the harmonic order and omega = 2 x pi x f_fundamental.
Filters are typically tuned slightly below the target harmonic (e.g., 4.7th instead of 5th) to avoid resonance with system impedance.
A series LC filter tuned to a specific harmonic frequency provides a low-impedance path that diverts harmonic current away from the system.
### Design Steps
1. **Capacitive reactance at fundamental**: Xc = V^2 / kVAR
2. **Inductive reactance at fundamental**: Xl = Xc / n^2
3. **Capacitance**: C = 1 / (omega x Xc)
4. **Inductance**: L = Xl / omega
Where n is the harmonic order and omega = 2 x pi x f_fundamental.
Filters are typically tuned slightly below the target harmonic (e.g., 4.7th instead of 5th) to avoid resonance with system impedance.
计算示例
5th harmonic filter, 50 kVAR, 480 V, 60 Hz system.
- Tuning frequency: 60 x 5 = 300 Hz
- Xc at 60 Hz: 480^2 / 50000 = 4.608 ohms
- Xl at 60 Hz: 4.608 / 25 = 0.184 ohms
- C = 1 / (377 x 4.608) = 575.7 microfarads
- L = 0.184 / 377 = 0.49 mH