EPE Association: EPE 1997 – 07: Lecture Session L2c: MODULATION STRATEGIES

EPE 1997 – 07: Lecture Session L2c: MODULATION STRATEGIES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 07: Lecture Session L2c: MODULATION STRATEGIES

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   ANALYSIS OF SPECTRAL EFFECTS OF RANDOM PWM STRATEGIES FOR VOLTAGE-SOURCE INVERTERS
By A.M. Trzynadlowski; R.L. Kirlin; M.M. Bech; F. Blaabjerg; J.K. Pedersen [View]
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Abstract: Random pulse width modulation (RPWM) techniques for voltage-source inverters have gained a strong foothold in modem power electronics. Of the several randomization schemes proposed, dithering the widths of consecutive switching intervals seems most promising in all aspects. In this paper, for a discrete distribution of non-rational interval widths, powers in the de and fundamental components of the switching function are determined. It is shown that ideally there is no power in any other frequency components, and that the optimal solution consists simply in two equiprobable widths. An expression for the noise power spectral density that results from the randomization is provided, and numerical and experimental examples are presented.

   NOVEL RANDOM PWM METHOD BASED ON NORMALLY DISTRIBUTED RANDOM DATA
By B. Kaku; I. Miyashita; S. Sone [View]
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Abstract: As an effective means to reduce the acoustic magnetic noise and EMI, a novel random pulse width modulation (PWM) method based on normally distributed random data is proposed. In conventional random PWM method, the uniformly distributed random data is often used, so the peaks of harmonics are not sufficiently reduced yet. The aim of this novel random PWM method is to spread the frequency distribution of harmonics more flat by using the normally distributed random data. In this paper, the basic principle of this novel random PWM method is discussed and the analytical comparison with conventional random PWM methods is performed. Finally, the experimental results are illustrated.

   MODULATION TECHNIQUES APPLIED TO HIGH POWER 3 LEVEL GTO's CONVERTER FOR ASYNCHRONOUS MOTOR DRIVES
By C. Bacigalupo; M. Baragli; M. Carpita; L. Puglisi; G. Striano [View]
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Abstract: In this paper, after a short review of the main characteristics of the NPC-GTO Double Converter jointly developed by EPRI and i\nsaldo, the studies performed for the modulation teclmiques to be used in an NPC double converter are presented. Both Space Vector Modulation (SVM) and Harmonic Reduction Modulation (HRM) have been studied and tested. A third modulation technique, Optimal Space Vector Modulation (OSVM) has been studied. The optimal space vector modulation method has some of the benefits of both SVR and HRM. In the OSVM technique the durations of switching cycles are the optimization variables. The method is based on converting the reference voltage vector V.ref (t) into a sequence of discrete sampled values V.ref (ts) with the sampling instants Ts no more regularly space as conventional scheme. This. optimal technique is applied to a 3 level inverter, in order to reduce harmonic currents at given switching frequencies. The optimal scheme can be carried out off-line and it can be implemented at the same cost as the conventional scheme.

   A PWM STRATEGY USING A DISCONTINUOUS MODULATING SIGNAL FOR FULL-BRIDGE INVERTERS
By A. Eisinberg; G. Palmieri; C. Picardi [View]
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Abstract: The paper presents a new natural bipolar PWM strategy suitable for fullbridge inverters. The proposed modulating signal is obtained adding a simple discontinuous waveform to the classic sinusoidal signal. The output waveform is investigated by means of a theoretical model, and then the total harmonic distorsion is calculated. A value of this performance criterion lower than that relative to the sinusoidal PWM technique reflects the superiority of the proposed PWM strategy.

EPE 1997 – 07: Lecture Session L2c: MODULATION STRATEGIES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 07: Lecture Session L2c: MODULATION STRATEGIES
	[return to parent folder]

	ANALYSIS OF SPECTRAL EFFECTS OF RANDOM PWM STRATEGIES FOR VOLTAGE-SOURCE INVERTERS By A.M. Trzynadlowski; R.L. Kirlin; M.M. Bech; F. Blaabjerg; J.K. Pedersen	[View] [Download]
Abstract: Random pulse width modulation (RPWM) techniques for voltage-source inverters have gained a strong foothold in modem power electronics. Of the several randomization schemes proposed, dithering the widths of consecutive switching intervals seems most promising in all aspects. In this paper, for a discrete distribution of non-rational interval widths, powers in the de and fundamental components of the switching function are determined. It is shown that ideally there is no power in any other frequency components, and that the optimal solution consists simply in two equiprobable widths. An expression for the noise power spectral density that results from the randomization is provided, and numerical and experimental examples are presented.

	NOVEL RANDOM PWM METHOD BASED ON NORMALLY DISTRIBUTED RANDOM DATA By B. Kaku; I. Miyashita; S. Sone	[View] [Download]
Abstract: As an effective means to reduce the acoustic magnetic noise and EMI, a novel random pulse width modulation (PWM) method based on normally distributed random data is proposed. In conventional random PWM method, the uniformly distributed random data is often used, so the peaks of harmonics are not sufficiently reduced yet. The aim of this novel random PWM method is to spread the frequency distribution of harmonics more flat by using the normally distributed random data. In this paper, the basic principle of this novel random PWM method is discussed and the analytical comparison with conventional random PWM methods is performed. Finally, the experimental results are illustrated.

	MODULATION TECHNIQUES APPLIED TO HIGH POWER 3 LEVEL GTO's CONVERTER FOR ASYNCHRONOUS MOTOR DRIVES By C. Bacigalupo; M. Baragli; M. Carpita; L. Puglisi; G. Striano	[View] [Download]
Abstract: In this paper, after a short review of the main characteristics of the NPC-GTO Double Converter jointly developed by EPRI and i\nsaldo, the studies performed for the modulation teclmiques to be used in an NPC double converter are presented. Both Space Vector Modulation (SVM) and Harmonic Reduction Modulation (HRM) have been studied and tested. A third modulation technique, Optimal Space Vector Modulation (OSVM) has been studied. The optimal space vector modulation method has some of the benefits of both SVR and HRM. In the OSVM technique the durations of switching cycles are the optimization variables. The method is based on converting the reference voltage vector V.ref (t) into a sequence of discrete sampled values V.ref (ts) with the sampling instants Ts no more regularly space as conventional scheme. This. optimal technique is applied to a 3 level inverter, in order to reduce harmonic currents at given switching frequencies. The optimal scheme can be carried out off-line and it can be implemented at the same cost as the conventional scheme.

	A PWM STRATEGY USING A DISCONTINUOUS MODULATING SIGNAL FOR FULL-BRIDGE INVERTERS By A. Eisinberg; G. Palmieri; C. Picardi	[View] [Download]
Abstract: The paper presents a new natural bipolar PWM strategy suitable for fullbridge inverters. The proposed modulating signal is obtained adding a simple discontinuous waveform to the classic sinusoidal signal. The output waveform is investigated by means of a theoretical model, and then the total harmonic distorsion is calculated. A value of this performance criterion lower than that relative to the sinusoidal PWM technique reflects the superiority of the proposed PWM strategy.