{"title":"Feedforward-Enhanced Feedback Control of Output Voltage of a GaN-Based High-Power-Density Single-Phase Transformer-Less Online UPS","authors":"Maida Farooq, Danish Shahzad, K. Afridi","doi":"10.1109/APEC43599.2022.9773406","DOIUrl":null,"url":null,"abstract":"This paper presents an improved control technique for the dual-mode inversion stage of the recently proposed high-power-density common-neutral single-dc-bus (CN-SDB) single-phase online uninterruptible power supply (UPS). The dual-mode inversion stage operates in buck or buck-boost mode depending on the polarity of the output reference voltage, and originally utilized feedback control to produce a sinusoidal output voltage. Under feedback control, this dual-mode operation leads to a substantial dc-offset and degradation of the output voltage total harmonic distortion (THD), which is unacceptable for practical applications. A feedforward-enhanced feedback control methodology is proposed to substantially reduce the dc-offset and THD of the output voltage. An analytical model capturing the dynamics of the inversion stage under feedforward-enhanced feedback control is also presented to aid in the selection of appropriate feedforward gains and the design of the feedback compensator. A 1-kVA high-power-density high-efficiency GaN-based prototype of the CN-SDB single-phase online UPS is designed, built, and tested to validate the proposed control strategy. The feedforward-enhanced feedback control strategy results in about 80% reduction in the dc-offset and 50% reduction in the output voltage THD compared to the original feedback-only control.","PeriodicalId":127006,"journal":{"name":"2022 IEEE Applied Power Electronics Conference and Exposition (APEC)","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2022-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"3","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"2022 IEEE Applied Power Electronics Conference and Exposition (APEC)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/APEC43599.2022.9773406","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 3
Abstract
This paper presents an improved control technique for the dual-mode inversion stage of the recently proposed high-power-density common-neutral single-dc-bus (CN-SDB) single-phase online uninterruptible power supply (UPS). The dual-mode inversion stage operates in buck or buck-boost mode depending on the polarity of the output reference voltage, and originally utilized feedback control to produce a sinusoidal output voltage. Under feedback control, this dual-mode operation leads to a substantial dc-offset and degradation of the output voltage total harmonic distortion (THD), which is unacceptable for practical applications. A feedforward-enhanced feedback control methodology is proposed to substantially reduce the dc-offset and THD of the output voltage. An analytical model capturing the dynamics of the inversion stage under feedforward-enhanced feedback control is also presented to aid in the selection of appropriate feedforward gains and the design of the feedback compensator. A 1-kVA high-power-density high-efficiency GaN-based prototype of the CN-SDB single-phase online UPS is designed, built, and tested to validate the proposed control strategy. The feedforward-enhanced feedback control strategy results in about 80% reduction in the dc-offset and 50% reduction in the output voltage THD compared to the original feedback-only control.