Microcomputer based ultrasonic power MOSFET inverter with monitoring and protection circuit

Dissertant

Atiea, Husayn Abd al-Radha

University

University of Technology

Faculty

-

Department

Department of Electrical Engineering

University Country

Iraq

Degree

Master

Degree Date

1998

English Abstract

In this research, the design and construction of a new system used a microcomputer for inverter controlling.

This inverter is designed by using power electronics switches type MOSFET.

The MOSFETs are controlled by pulses depending on sampled Sinusoidal Pulse Width Modulation (SPWM) technique with frequency ratio changing.

The PWM pulses are generated by comparing a reduce sine wave with carrier triangular wave.

The first wave is obtained through special designed machine language program.

This program also checks the system state firstly then generate the three phase reference waves with frequency and voltage control ability.

This control operation is assisted by additional designed circuits, The second wave is obtained by an external oscillator with ultrasonic frequency 24KHz : the high range of carrier frequency is used to eliminate low order harmonics.

Torque pulsation, and to ensure safe and reliable control operation.

The range of inverter output frequency is (0 ⟶50Hz) with 0.2Hz frequency step, this inverter output waveform is ased to control the 3-ph induction motor speed.

Which is commonly ased in practical applications.

Constant voltage-to-frequency (V / f) ratio is maintained through the program leading to constant flux for speed range.

A simulation program designed to clarify the generation steps of inverter line-to-neutral output voltage and calculate the harmonics distribution for different cases.

The Harmonic Loss Factor (HLF) is used as a quality factor of system performance.

In this research, different circuits are designed to protect the system from elevation voltage, current, and temperature with additional indicators, one for each case, Digital Revolution Per Minute (RPM)-meter is designed to calculate the induction motor speed carefully for (0 ⟶9999) revolution per minute speed range The experimental system is based on an NEC-6001 personal computer which built around Z-80 microprocessor.

The real time results are in close agreement with the theoretical results and that clarify in simulation program and experimental 3-ph output voltages.

Main Subjects

Electronic engineering

Topics

• Integrated circuits

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-306331