A Current Reconstruction Strategy Following the Operation Area in a 1-Shunt Inverter System

• Published in: Energies (Basel) Vol. 12; no. 8; p. 1423
• Main Authors: Park, Chang-Hwan, Dong-Youn, Kim, Han-Beom Yeom, Yung-Deug Son, Jang-Mok, Kim
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 13.04.2019
• Subjects: AC motor drive; Acoustic noise; Anechoic chambers; Coordinate transformations; current estimation; current reconstruction; Digital signal processors; Electric potential; Harmonic distortion; Household appliances; Information systems; intermittent PWM shift; Inverters; Loop transfer functions; low modulation region; Methods; Noise; Noise reduction; Phase current; Pulse duration modulation; Reconstruction; Sensors; shunt resistor; SVPWM; three-phase inverter; Voltage; United Kingdom > UK; United States > US
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en12081423

To reduce the cost of the inverter system in home appliances, a method using a shunt resistor at the DC-link can be substituted for a method using two current sensors at the inverter output. However, the minimum time of the active vector is required to sample the accurate current using a 1-shunt resistor. Therefore, many studies have been conducted investigating current reconstruction methods in the unmeasurable region of the current. The conventional methods using voltage injection have some problems such as high THD (Total Harmonic Distortion) and acoustic noise, because the PWM pattern is shifted. In addition, the current reconstruction is inaccurate in a low modulation region. In this paper, the cause of the noise in conventional methods is analyzed and a simple current reconstruction method based on an average current estimation and a current reference is utilized for reducing acoustic noise. In an immeasurable area, especially a low modulation region, an intermittent PWM shift method is proposed to enhance the accuracy of the reconstructed current. Therefore, a control strategy that combines all of the mentioned methods is implemented for the entire operating range. The effectiveness of the proposed methods is verified through the experimental results and the results of sound measurement in an anechoic chamber are included to compare with the acoustic noise.