A Novel Pulse-Width and Amplitude Modulation (PWAM) Control Strategy for Power Converters

Abstract

Typical power electronic converters employ only pulse width modulation (PWM) to generate specific switching patterns. In this paper, a novel control strategy combining both pulse-width and amplitude modulation strategies (PWAM) has been proposed for power converters. The Pulse Amplitude Modulation (PAM), used in communication systems, has been applied to power electronic converters. This increases the degrees of freedom in eliminating or mitigating harmonics when compared to the conventional PWM strategies. The role of PAM in the novel PWAM strategy is based on the control of the converter's dc sources values. Software implementation of the conventional PWM and the PWAM control strategies has been applied to a five-level inverter for mitigating selective harmonics. Results show the superiority of the proposed strategy from the THD point of view along with a reduction in the inverter power dissipation.

Phase‐shifted pulse‐width‐amplitude modulation for quasi‐Z‐source cascade multilevel inverter‐based photovoltaic power system

“…Recently, pulse-width-amplitude modulation (PWAM) was applied to the three-phase voltage source inverter (VSI) [22][23][24][25], qZS matrix converter [26,27] and the traditional CMI [28]. The VSI demonstrates an 87% switching loss reduction by using the PWAM technique, and requires a much lower capacitance for the dc-link capacitor.…”

“…As a result, the PWAM‐based whole system presents a higher power density with a higher efficiency, less volume and lighter weight than the traditional PWM‐based system. Ghoreishy et al [28] combined the selective harmonic elimination PWM (SHE‐PWM) with the PWAM in application to the CMI‐based motor drive system. However, controllable dc sources, such as the employed PWM rectifier in [28], are required to realise the pulse‐amplitude modulation, which involved a complex system topology and control.…”

An Advanced Modulation Technique Featuring Common Mode Voltage Suppression for Three-Phase Neutral Point Clamped Back to Back Converters

“…Suppose that the ability to change the pulse amplitude could be added to the power inverter, like changing the pulse width. In that case, the quality of conventional PWM control methods will be further improved [6]. The PAM technique stabilizes the amplitude modulation index at specific values and instead changes the DC link voltage in the middle.…”

“…The CMV is significantly reduced by regulating the DC link voltage, reducing the harmonic amplitude using PAM, and realizing the SVM method in it (leading to eliminating zero vectors). Moreover, the motor torque ripple is reduced, and a significant improvement in the THD of output voltage and current is achieved [6]. Therefore, the control circuit of the back-to-back converter must be designed to respond to the dynamic speed and produce the DC link voltage with mentioned specifications.…”

Modified selective harmonic elimination employed in four-leg NPC inverters

“…In selective harmonic elimination pulse width amplitude modulation (SHE-PWAM), the amplitude of dc input voltage can be considered as extra degree of freedom in addition to switching angles [22], thus, as the switching frequency depends on the number of switching angles, selecting the amplitude of dc input voltage as a degree of freedom results in eliminating one extra harmonic order without increasing the switching frequency. In this paper, SHE-PWAM for threelevel four-leg NPC inverter considering the aforementioned extra degree of freedom is designed.…”