This paper presents an extended dq0-model for small delta-connected Permanent Magnet Synchronous Machines (PMSM), the design of a prototype and the parameterization of the model parameters by testbench measurement. The familiar dq-fundamental equations are thereby extended to consider harmonic effects. This allows the inclusion of the zero-sequence flux-linkage. The model, based on the dq0-flux-linkages and the stator resistance, enables the calculation of the zero-sequence current and a more precise inner torque estimation compared to state of the art fundamental models. The rotor position dependent dq-flux-linkage estimation is based on the measured dq-voltages and the solution of the simplified differential system equation. Detection of the zerosequence current yields to the zero-sequence flux-linkage. In this paper, we also present a prototype design of a PMSM machine with additional zero-sequence current sensing. Testbench measurement at constant controlled currents enables the parameter identification. For validation, the identified parameters are compared with existing Finite Element Analysis.

Delta-connected stator windings are often used in mass production of small Permanent Magnet Synchronous Machines (PMSMs). In comparison to star-connected stator windings, a delta-connected winding system offers advantages for manufacturing and lowers production costs. A main disadvantage of motors with such a winding system are additional losses caused by the Zero-Sequence Current Component (ZSCC). In this paper the ZSCC and its impact on the generated losses in a deltaconnected PMSM used as a traction motor for a pedal electric cycle (Pedelec) is analysed. The calculated results are compared to those of a star-connected PMSM with the same design. We will show that the amplitude of the ZSCC depends on the operating point of the machine. As a result, the copper losses in the deltaconnected machine are up to 5.8 % higher than the ones in the star-connected machine. On the other hand, the iron losses are 1 % smaller in the delta-connected machine. The efficiency of the delta-connected machine is still up to 4 % smaller.

No abstract

Design-oriented modeling approaches, such as finite element analyses (FEA), rely on accurate material data. However, manufacturers rarely provide the necessary data for cookware used in domestic induction heating. Due to the multi-layered structure of the cookware bottom, conventional measurement methods for the characterization of magnetic material are not applicable without great effort in preparation of suited material specimen. This contribution proposes a novel measurement method that allows determining the electromagnetic properties of the ferromagnetic bottom layer of cookware. The proposed measurement method is based on the minimization of deviation between measurement and simulation data in dependence of material properties. By characterization of the ferromagnetic bottom layer of a material specimen made from multiple layers, the feasibility of the method is shown. The results presented for the magnetic material characterization are validated using Epstein frame measurements. It is shown that the deviation between the magnetization curve determined with the proposed method and the tip of the hysteresis curve measured using the Epstein frame is approximately 3 %. To validate the results presented for the specific electrical resistance, a microhmmeter is used. The relative error between both measurements is approximately 16 %.

No abstract