Spread Spectrum Modulation for LCL Filter Design

The LCL filter is often the bulkiest component in grid-tied converters, which is designed to satisfy the grid harmonic standards such as IEEE519. To reduce the filter requirement, application of the spread spectrum modulation (SSM) to LCL filter design is investigated in this paper. Filter design methodology for SSM is presented and a comparative analysis between the conventional pulse-width modulation (PWM) and SSM is carried out focusing on their impact on the filter design. It is shown that under the same average switching frequency, LCL filter parameters required for SSM can be substantially reduced compared to the conventional PWM.