Nowadays renewable energies are gradually taking over, as natural resources are slowly diminuating and ecological aspects are getting more and more important.

Our industry partner is working at a project whereby windenergy, especially low winds, is transformed to electricity. Thanks to a wind turbine and a synchronous generator, electrical current with variable frequency and amplitude is being produced. The aim of this diploma work was to process the generators energy so that it can be entered by a industry inverter into the public net. This inverter needs constant dc-voltage.

The works aim was to solve this problem by using an uncontrolled rectifier bridge and a regulated boost converter. We created with Mattlab Simulink a model of the circuit in order to recognise difficulties in advance and to collect precious information for the construction. A control- and power print has been designed in which first of all the analysis of the parts and the power print did use unexpectedly a great amount of time. The various elements were built in the case and tested.

The circuit was tested too and it works up to a certain amount of kilowatt. As no suitable power resistant could be found, the measurements with the rated output didn't take place. First tests with the connected inverter were made, but could not have been brought to a end by now.

The task of our Diploma consisted developing of a controller for a magnetic powder brake. Magnetic powder brakes are used everywhere, where in the stationary status torques are measured. The large advantage of the magnetic powder brake is the possibility to brake a drive with a constant torque up to the deadlock. At the ZHW magnetic powder brakes were purchased some time ago in order to test electric motors on test stands. The principle of the magnetic powder brake is based on the phenomenon of the magnetic field, which is developed if a coil is flowed through by a current. The powder which is enclosed between stator and rotor compresses itself continuously with rising coil current. The rotor is connected by the compression of the powder more strongly with the stator and it develops the desired brake torque. The problem of the brakes was now on the controllers. The available devices which were available at our school were not suitable for the operation. With a temperature increase of the brake the required brake torque could not be held any longer.

At the beginning of the work we concerned ourselves with the problem of the measurement of torque. The torque on our brake is measured by strain gauges. The principle of the strain gauges consists of the fact that a wire modifies its resistance value if it is stretched or tossed. After some static and stationary measuring attempts we noticed that no reliable measuring results were supplied from the strain gauges. Before we could developing a regulator we had to solve these problems. At the end we decided to replace the strain gauges halfbridge by a fullbridge. Only now, as the problems of the measurement of torque and the occurring remanence were solved, we could work straight forward with the development and the implementation of the controller concern itself.

Because the mentioned problems took some time up unfortunately we could not achieve our target of a fixedfinished controller in a use-case.