계통연계형 인버터의 출력 전류 고조파 분석 및 필터 설계

Abstract

This paper deals with a cost-effective design method of an LCL filter for a grid connected inverter. The harmonic components injected into a power grid may results in severe problems including resonance phenomena and malfunction of sensitive electronic devices. Therefore, it is necessary to limit the harmonic current injection magnitude of a grid-connected PWM inverter. To reduce the harmonic components L, LC, and LCL filters are used between the PWM inverter and power grid. Usually, the cost and volume of an LCL filter are lower and smaller than those of an L or LC filter. Therefore, recently, most grid-connected inverter adopts an LCL filter. There are many design methods for the LCL filter according to the design view point. This paper proposes an economical design method of an LCL filter for a grid-connected inverter to reduce the cost of an LCL filter. The proposed economical LCL filter design method meets harmonics management criteria (IEEE 519-2014). The usefulness of the proposed method is verified through simulation results carried out with 3-phase 10 kVA grid-connected PWM inverter. It is expected that the proposed design method can be used for a cost-effective implementation of grid-connected PWM inverters.