Programmable Device Circuits and Systems

A. Ramya ¹, R. L. Helen Catherine ¹

Affiliations
1 Anna University of Technology, Coimbatore, IN

Abstract

In this paper, a vibration suppression scheme is proposed for the riding comfort of elevator using dead time elimination scheme. Dead time is used for pulse width-modulation (PWM) controlled inverter/converter control to avoid shoot through of high-side and low-side power devices. To deal with dead time problems polarity of current detection is necessary The presented scheme does not require current sensors for polarity detection. Depending on the polarity of terminal voltage of each leg the current polarity is determined. Current polarity is detected regularly with a sampling frequency which is higher than the switching frequency to reduce the detection error. Hence separate power supplies are not required which reduces the bulkiness and cost of this scheme. Based on the polarity of sensed voltage the SPWM signals are generated to turn ON the switches of inverter. The presented scheme eliminates the dead time and therefore improves output voltage loss and current distortion and torque ripples. The corresponding elevator vibrations are conspicuously reduced. Simulation results for single phase and three phase inverter are done in MATLAB. The above scheme is verified by implementing it in a single phase inverter controlled motor. Hardware results are presented to demonstrate the effectiveness of the scheme.

Keywords

Dead-Time Elimination, Elevator, Pulse Width Modulation, Vertical Vibration.

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R. L. Helen Catherine ¹, S. Nithyapriya ¹

Affiliations
1 Anna University of Technology, Coimbatore, IN

Abstract

In this paper the simplest PV system consists of multiple solar cells connected to form a PV module commercially available modules range in power from 10 watts to 300 watts. One or more of these modules are connected to an inverter which convert’s direct-current (DC) output of other modules into alternating current (AC). Optionally, batteries may provide energy storage or backup power in case of a power interrupting or outage on the grid. the interface between Photovoltaic power supply and the grid rely on the centralized inverter technology A complete grid-tied solar system consists roof mounted solar modules, wiring, and grid tie inverter. The inverter used here is a hybrid clamped inverter. In this topology, the dc-link capacitor voltages can be balanced without additional circuitry or separated dc voltage sources, regardless of load characteristics. It can be used in real and reactive power conversion applications. The topology structure, operating principle and self-voltage balancing ability are analyzed. The PWM control method called higher and lower carrier cells alternative phase opposition PWM (HLCCAPOPWM) is employed. Comparision of various PWM techniques for the hybrid clamped inverter is done. Simulation results are also presented.

Keywords

Hybrid Clamped Multilevel Inverters, Pulse Width Modulation, Switching.

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