Search results for "Pulse-frequency modulation"
showing 4 items of 4 documents
Architecture of a digital PFM controller for IC implementation
2006
This paper presents a digital controller architecture oriented to IC implementation. The classical digital pulse width modulator (D-PWM), using digital analog converter (DAC), is replaced with a Sigma-Delta (/spl Sigma//spl Delta/) modulator based on pulse frequency modulator (PFM) technique. Results of an investigation from a prototype for DC-DC converter, in terms of simulated and experimental performances, are reported, together with harmonic frequency investigation. The control function design is implemented on a field programmable gate array (FPGA). As a consequence of good agreement between simulated and experimental results, the proposed architecture realizes a digital control loop w…
Comparative evaluation of pulse width modulation techniques on effective DC link voltage utilization of grid connected inverter
2016
In this paper, comparison between two different Pulse Width Modulation (PWM) techniques employed for three phase voltage source inverter (VSI) is discussed. The three phase voltage source inverter is basic topology used to supply a grid. In this paper we have design a LC filter between the inverter and the grid in order to stabilize the output voltage. The filter gives sinusoidal three phase voltage at the output of the inverter with almost zero/less harmonic distortion. A suitable PWM technique is employed to obtain the required output voltage in the line side of the inverter. The PWM generation techniques used mainly based on sinusoidal based Pulse Width Modulation (SPWM) and Space Vector…
Control of the speed of a DC motor by employeeing pulse width modulation (PWM) technique
2009
This paper is mainly focused on the technique of pulse width modulation for controlling the speed of a 12 volt DC motor more efficiently. A potentiometer was used to generate a wide variety of pulses. The output of the controlling circuit (Pulse Width) was connected to the second circuit as input for direction control. Here a single push switch was used to change the state (stopforward-stop-reverse) of the DC motor. These two circuits were combined into one for ease of use. Third circuit was designed to measure the speed of the motor by employing an opto-electronic sensor, an amplifier and a two blade fan to interrupt the signal transmission of the sensor. Finally, the output of the sensor …
Mechanical models of amplitude and frequency modulation
2005
This paper presents some mechanical models for amplitude and frequency modulation. The equations governing both modulations are deduced alongside some necessary approximations. Computer simulations of the models are carried out by using available educational software. Amplitude modulation is achieved by using a system of two weakly coupled pendulums, whereas the frequency modulation is obtained by using a pendulum of variable length. Under suitable conditions (small oscillations, appropriate initial conditions, etc) both types of modulation result in significantly accurate and visualized simulations.