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Frequency modulated PWM for voltage source inverters

Journal Article


Abstract


  • The frequency modulation (FM) technique is proposed for the operation of voltage source static inverters. In conventional pulse width modulation (PWM) techniques the magnitude of carrier frequency and its multiples are significantly high. In the sine PWM method, at 0.5 modulation index the fundamental is 50% and the carrier component is more than 100% in magnitude of the supply voltage. The ratio of the carrier to fundamental magnitude increases further with reduction of the modulation index. Voltage source inverters having low- and medium-speed static switches use carrier frequency in the audio frequency range, resulting in acoustic noise. Also, if the carrier frequency is maintained low as in ac drives, the high magnitude of carrier may produce significant unwanted torques. These problems of conventional PWM technique may be reduced significantly by using frequency modulation in which the carrier is distributed within a defined band. A generalized mathematical model of frequency modulation technique is presented for static converters. The proposed technique also allows transition from frequency modulation to conventional PWM method if necessary. The performance of the proposed FM modulator is compared with the conventional PWM used in the control of static PWM converters. Simulation and experimental results are presented to validate the claims.

Publication Date


  • 2001

Citation


  • Rahman, K. M., Choudhury, M. A., Rezwan Khan, M., Kashem, M. A., & Yusoff, M. R. (2001). Frequency modulated PWM for voltage source inverters. International Journal of Power and Energy Systems, 21(2), 74-79.

Scopus Eid


  • 2-s2.0-2242465858

Web Of Science Accession Number


Start Page


  • 74

End Page


  • 79

Volume


  • 21

Issue


  • 2

Abstract


  • The frequency modulation (FM) technique is proposed for the operation of voltage source static inverters. In conventional pulse width modulation (PWM) techniques the magnitude of carrier frequency and its multiples are significantly high. In the sine PWM method, at 0.5 modulation index the fundamental is 50% and the carrier component is more than 100% in magnitude of the supply voltage. The ratio of the carrier to fundamental magnitude increases further with reduction of the modulation index. Voltage source inverters having low- and medium-speed static switches use carrier frequency in the audio frequency range, resulting in acoustic noise. Also, if the carrier frequency is maintained low as in ac drives, the high magnitude of carrier may produce significant unwanted torques. These problems of conventional PWM technique may be reduced significantly by using frequency modulation in which the carrier is distributed within a defined band. A generalized mathematical model of frequency modulation technique is presented for static converters. The proposed technique also allows transition from frequency modulation to conventional PWM method if necessary. The performance of the proposed FM modulator is compared with the conventional PWM used in the control of static PWM converters. Simulation and experimental results are presented to validate the claims.

Publication Date


  • 2001

Citation


  • Rahman, K. M., Choudhury, M. A., Rezwan Khan, M., Kashem, M. A., & Yusoff, M. R. (2001). Frequency modulated PWM for voltage source inverters. International Journal of Power and Energy Systems, 21(2), 74-79.

Scopus Eid


  • 2-s2.0-2242465858

Web Of Science Accession Number


Start Page


  • 74

End Page


  • 79

Volume


  • 21

Issue


  • 2