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Logo: Institute for Drive Systems and Power Electronics/Leibniz Universität Hannover
Logo Leibniz Universität Hannover
Logo: Institute for Drive Systems and Power Electronics/Leibniz Universität Hannover
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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.


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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.


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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.


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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,
  • commutation,
  • reactive power,
  • harmonics on the DC and AC side.


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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.


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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

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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.


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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

  • performance,
  • 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.


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