This master thesis deals with the determination of losses and other electromagnetic quantities
of a 6-phase permanent magnet synchronous machine using the synthetic load (SL) method. The work is a continuation of the master thesis "Determination of losses of a 6-phase permanent magnet synchronous machine using the synthetic load method" by A. Darovic. The focus of this MSc thesis is a further improvement of the SL method by automation of measurements, which, due to faster execution of measurements and a precisely defined measurement protocol, leads to higher repeatability and quality of the measurement results.
In the introduction, we first mention the advantages of using multiphase machines and describe the different approaches for determining the operating characteristics of electrical machines. Here, we mainly identify the advantages of multiphase machines and the SL method, which led us to the combination of the selected drive and the method of determining the operating characteristics in the context of the master thesis. In the second part, we also briefly describe the automation of measurement itself and its advantages, limitations and requirements when implementing a measurement instrument in an automated process.
Chapter 2 is dedicated to the description of the SO method. The concept of the SO method is described using a static mathematical model and the power flow in the drive. The input power fed through the inverter is equal to the power loss of the whole drive, while the bulk of the power circulates between the motor and generator winding sets within the machine. In this master thesis we have focused on the determination of the losses in the machine.
In Chapter 3 we present the Ansys Motor-CAD simulation tool, which we eventually use to further validate the use of the automated SL method. In this chapter we walk through the different segments, where we also give the actual parameters of the simulation model used.
A description of the actual measurement system is given in Chapter 4, where we list and briefly describe all the components that enable measurements to be performed using the SL method. Here, we focus on the 3-phase power analyzer Newtons4th PPA5530 that is crucial in the automated measurement process. As there is only one 3-phase instrument, the power measurement must be carried out in two steps, first measuring the input power of the motor set, then the input power of the generator set, making sure that the operating point and operating conditions are practically the same in both cases.
To minimize measurement times and to achieve the correct value and repeatability of the measurement results, the instrument must be set up accordingly. In Chapter 5, we thus present the influence of the different settings of the power analyzer, such as the synchronization on the measured signal and the acquisition window, on the calculation of the measurement results. At the end of the chapter, the most appropriate settings are determined on the basis of the measured mean values and standard deviations of the measurement results.
The integration of the instrument into an automated process is described in Chapter 6. Particular attention is paid to the description of the remote communication of the power analyzer with the computer, the measurement protocol in a single operating point and the automatic setting of the drive operating point.
In Chapter 7, an automated measurement system is used to measure the losses of a 6-phase synchronous machine with buried magnets. First, the repeatability of the measurement results based on the power and temperature rises between different sets of measurements of the same three-phase winding set and the repeatability when changing the set being measured are verified. This is followed by measurements of the rms values of the fundamental harmonics of the voltage, current and power factors of the two sets of windings and measurements of the input powers of the two winding sets at several measurement points. As mentioned above, the measurement results of the practical implementation are replicated in the Motor-CAD simulation environment to further validate the implementation of the automated SO measurement process.
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