Digital Simulation of a Line-commutated Rectifier
In electrical engineering, digital simulation systems are used for analysis of circuits and components. In this experiment, a 6-pulse thyristor bridge rectifier shall be tested as an example, in order to find out how simulation systems can be used to describe electric processes.
DC to DC Buck Converter with GTO Thyristor
In this experiment, a DC to DC buck converter with GTO thyristors shall be tested, paying special attention to
- the current and voltage conditions of DC to DC buck converters,
- the switching behaviour and the characteristics of a GTO thyristor,
- the control of DC to DC buck converters.
Another topic is to get acquainted with a method for determining switching and forward power losses in case of power semiconductors by using a digital storage oscilloscope.
PWM Voltage Source Inverter with Transistors
PWM voltage source inverters are used for continuous speed control of three-phase motors. In this lab, a PWM voltage source inverter system with power transistors shall be tested considering the following aspects:
- current and voltage conditions in three-phase converters,
- valve load,
- principle of output voltage synthesis via pulse-width modulation,
- performance of PWM voltage source inverters under motor load.
Line-commutated Rectifier in Three-phase Bridge Configuration
The experiment deals with the functioning and performance of a line-commutated rectifier in a three-phase bridge configuration. Particular tests refer to
- waveforms of currents and voltages for different operating states,
- reactive power,
- harmonics on the DC and AC side.
Series Resonant Inverter
Series resonant inverters belong to the group of load-commutated inverters. The voltage needed for commutation is provided by the load.
In this experiment, a series resonant inverter is examined. Depending on the clock frequency and on the oscillating circuit parameters, the following parameters are measured and evaluated:
- waveforms of voltage and current,
- control characteristic,
- turn-off time,
- inverter instability.
Switched Power Supplies
Power supplies are common to everybody in daily life. They are needed in all electronic devices or in their chargers to rectify and step down the single-phase line voltage of 230 V. The lab comprises:
• examination of a common switched power supply on the basis of a laptop power supply
• examination of single-phase rectification and its mains interaction
• overview on different isolating DC/DC converters
• examination of the isolating DC/DC converter in a laptop power supply
AC Power Controller
In this experiment, the electric characteristics of AC power controllers shall be investigated for different loads and depending on the trigger delay angle. The experiment especially deals with
- measurement of voltage and current waveforms,
- measuring of the control characteristic,
- determination of thyristor data,
- analysis of current harmonics.
The measurements obtained in the lab shall confirm the results achieved analytically during the preparation of the experiment.
PWM Voltage Source Inverter with Thyristors
This experiment deals with three-phase pulse-width modulated voltage-source inverters using thyristors. The experiment shall comprise investigations concerning
- control using pulse-width modulation (PWM),
- commutation of thyristors with auxiliary circuit according to Mc Murray,
- waveforms of the output voltages and currents, including harmonics.