Parameter Selection Method for Avoiding Resonance and Reducing Voltage Harmonics by Adopting C-Type Filters on A LCL Filter

This paper introduces the method of avoiding resonance and reducing voltage harmonics by connecting a C-type filter to the capacitor section of an inverter containing an LCL filter connected to the power system. For this purpose, we first set the parameters of the inverter and LCL filter. Then various equations were employed to appropriately determine the values of the capacitor, inductor, and resistor of the C-type filter. Utilizing these configured values, the overall transfer function was represented using the transfer functions of the inverter and filter. Subsequently, it was examined whether unstable resonance, as compared to the system impedance, could be avoided when using the C-type filter. Furthermore, in the frequency domain, the Total Harmonic Distortion (THD) was utilized to assess how much the voltage harmonics decreased when the C-type filter was included, compared to when only the LCL filter was present.