Design of passive filter components for switching band controlled DVR

This paper presents a filter structure for improving the performance of switching band controlled Dynamic Voltage Restorer (DVR) and a systematic design procedure for the passive filter components. The switching operation of VSI is accompanied by a band controller which restricts the injected voltages within a band, defined about a reference voltage. Switching band control method exhibits merits such as fast dynamic response, robustness, zero magnitude / phase errors and ease in implementation. The performance of the band controller is improved using a novel filter structure. Quantitative expressions involving the dynamics of DVR and variation in switching frequency are also derived. The passive filter components are designed based on switching frequency and inverter rating. The proposed filter structure and design procedure for the DVR filter components are validated by carrying out PSCAD simulation studies.