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Dead-time effects on the voltage spectrum of a PWM inverter

Moore, David C.; Odavic, Milijana; Cox, Stephen M.


David C. Moore

Milijana Odavic

Stephen M. Cox


An inverter converts a direct-current power supply to an alternating-current power supply. This con- version is achieved by switching the output between the inputs at high frequency. The resulting output voltage may be described by a high-frequency train of variable-width pulses. Pulse widths are slowly modulated so that this output waveform contains a prescribed low-frequency component, which may then be isolated by an appropriate filtering regime. Techniques for determining the full harmonic spec- trum of input and output voltages and currents are well established, at least for an idealised mathematical model of the inverter. However, this model assumes that changes of inverter configuration can be ef- fected instantaneously, which is not quite the case in practice. In fact, a small amount of dead time must be incorporated into switching regimes in order to avoid short circuits of the input. Although dead time is an important feature of real power conversion devices, its effects on output voltage spectra have not previously been fully determined (except by imposing rather restrictive approximations). This situation is remedied in the present paper, in which we present closed-form expressions for the coefficients of the harmonic spectrum, corroborated by simulations.


Moore, D. C., Odavic, M., & Cox, S. M. (2014). Dead-time effects on the voltage spectrum of a PWM inverter. IMA Journal of Applied Mathematics, 79(6),

Journal Article Type Article
Acceptance Date Jan 15, 2013
Online Publication Date Feb 5, 2013
Publication Date Jan 1, 2014
Deposit Date Apr 11, 2016
Publicly Available Date Apr 11, 2016
Journal IMA Journal of Applied Mathematics
Print ISSN 0272-4960
Electronic ISSN 1464-3634
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 79
Issue 6
Keywords power inverter; Fourier spectrum; harmonics; dead time
Public URL
Publisher URL
Additional Information This is a pre-copyedited, author-produced PDF of an article accepted for publication in IMA Journal of Applied Mathematics following peer review. The version of record is available online at


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