This paper investigates the acoustic noise radiated from two nominally identical induction motors when fed from sinusoidal, and asymmetric regular sampling subharmonic and space-vector pulsewidth modulation (PWM) converters. The theory for analyzing the noise spectrum is developed further to account for the interaction between the motor and the drive. It is shown that manufacturing tolerances c...

In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM) technique. According to the optical-fiber PWM method, the received sensing signal's pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a line...

Many current communication systems suffer from performance degradation due to the high sensitivity to high power peaks especially in the nonlinear devices. The author introduces a new concept based on the Pulse Width Modulation (PWM), namely MIMO-OFDM system based PWM (MO-PWM) to overcome this deficiency. Here, the peak-to-average power ratio (PAPR) problem in Orthogonal Frequency Division Mult...

Adjustable speed drive system requires variable voltage and frequency supply which is invariably obtained from a three-phase voltage source inverter (VSI). A number of Pulse Width Modulation (PWM) schemes are used to obtain variable voltage and frequency supply from an inverter. The most widely used PWM schemes for a three-phase VSI are carrier-based sinusoidal PWM and space vector PWM (SVPWM)....

In the application of vehicle power supply and distributed power generation, there are strict requirements for the pulse width modulation (PWM) converter regarding power density and reliability. When compared with the conventional insulated gate bipolar transistor (IGBT) module, the Reverse Conducting-Insulated Gate Bipolar Transistor (RC-IGBT) with the same package has a lower thermal resistan...

By analyzing the sources of energy and power loss in PWM (Pulse Width Modulation) controlled drivers of water electrolysis cells, it is possible to reduce the power dissipation and enhance the efficiency of such hydrogen production units. A PWM controlled power driver is based on a semiconductor switching element where its power dissipation might be a remarkable fraction of the total power dema...

This topic discusses the trade-offs between fixed-frequency pulse-width modulation (PWM) and pulsefrequency modulation (PFM) for portable DC/DC converter applications. PWM converters offer the benefit of predictable operating frequency, which may simplify the design of circuitry that suppresses electromagnetic interference (EMI). They also offer low output ripple characteristics and high effici...

This work shows that the direct PWM output electric signal, with a duty cycle controlled by light intensity, can be obtained using a circuit containing a saw-tooth voltage generator connected in series with a dc voltage source and a metal (semitransparent gate) oxide semiconductor capacitor (MOS-C). The internal PWM signal conversion occurs by the use of non-equilibrium physical processes in th...

Mitogen- and antigen-induced interferon-gamma (IFN-gamma) responses of peripheral blood leucocytes from cervids were evaluated by a commercial whole-blood assay. The assay was applied to Mycobacterium bovis-infected white-tailed deer and reindeer, M bovis BCG-vaccinated white-tailed deer and elk, and unvaccinated, uninfected white-tailed deer, fallow deer, elk and reindeer. The responses of the...

This paper proposes a new zero-current-switching (ZCS) pulsewidth modulation (PWM) switch cell that has no additional conduction loss of the main switch. In this cell, the main switch and the auxiliary switch turn on and turn off under zero-current condition. The diodes commutate softly and the reverse-recovery problems are alleviated. The conduction loss and the current stress of the main swit...