Implementation and Control of a DFIM in Matlab Simulink

Introduction—

MATLABSolutions demonstrate In this task we are going to design This paper presents The doubly fed induction machine (DFIM) or wound rotor induction machine (WRIM) are terms commonly used to describe an electrical machine, which has been used over many decades in various applications, often in the range of megawatts of power and also less commonly in the range of a few kilowatts. This concept of the machine is as an alternative to more common asynchronous and synchronous machines. It can be advantageous in applications that have a limited speed range, allowing a reduction in the size of the supplying power electronic converter as, for instance, in variable-speed generation, water pumping and so on.

The typical supply configuration of the DFIM is shown in video. The stator is supplied by three-phase voltages directly from the grid at constant amplitude and frequency, creating the stator magnetic field. The rotor is also supplied by three-phase voltages that take a different amplitude and frequency at steady state in order to reach different operating conditions of the machine (speed, torque, etc.). This is achieved by using a back-to-back three-phase converter, as represented in the simple schematic in the video. This converter, together with the appropriate control strategy, is in charge of imposing the required rotor AC voltages to control the overall DFIM operating point and to perform the power exchange through the rotor to the grid. Although a voltage source converter is shown, different configurations or converter topologies could be utilized. Further details regarding the operation of the machine are described in subsequent sections.

Electric Equations:

The relationships between the different frequencies of the machine are basics that must be known prior to the study of the electric equations of the DFIM. Thus, the equation that relates 𝜔s (frequency of stator voltages and currents), 𝜔r (frequency of rotor voltages and currents) and 𝜔m (rotor electrical speed) is as follows:

The relation between the mechanical speed of the shaft Ωm and the electrical speed depends on the pole pairs of the machine: