This study presents a novel approach to the design process of a permanent-magnet flux-modulated machine by simultaneously focusing on the machine major advantage and disadvantage, that is, the high torque density and low power factor. The machine can be designed with a high power factor while retaining the high torque density. To do so, they both need to be described precisely. The torque equation is improved by considering the stator-winding leakage flux. It determines the relation between the geometric parameters and the torque more accurately. The power-factor equation is derived from the electric equivalent circuit representing the simplest description of the machine. The machine geometry optimized with the design of experiments via Taguchi methods assures the best possible performance within the set limitations. It is shown that using the proposed design process makes the permanent-magnet flux-modulated machine more appropriate than the classical synchronous machine for the direct drive applications requiring a high torque density, low weight and high efficiency.
COBISS.SI-ID: 11256916
This paper presents a nonlinear sliding mode control (SMC) scheme for interior permanent magnet synchronous motors (IPMSMs). The proposed SMC is able to reduce the settling time without an overshoot by giving a low damping ratio at the initial time and a high damping ratio as the output reaches the desired setpoint. At the same time, it enables a fast convergence in finite time. To improve the efficiency of a system in the constant torque region, the control system incorporates the maximum torque per ampere (MTPA) algorithm. The stability of the nonlinear sliding surface is guaranteed by Lyapunov stability theory. The effectiveness of the proposed nonlinear SMC scheme is verified experimentally. From these experimental results, the proposed nonlinear SMC method reveals a faster transient response, smaller steady-state speed error, and low sensitivity to system uncertainties.
COBISS.SI-ID: 11659860
The main objective of this study was to investigate whether the educational content the e-learning practical work presented to the students with different professional backgrounds enhanced their knowledge acquired via lectures during EBTT. We compared the learning outcome assessed in two experimental groups undergoing the e-learning practical work: electrical engineers and natural scientists. The same level of knowledge on the post-course examination was reached in both groups. The results indicate that our e-learning platform supported by blended learning approach provides an effective learning tool for populations with mixed professional backgrounds and thus plays an important role in bridging the gap between scientific domains involved in multidisciplinary applications.
COBISS.SI-ID: 11330900
Magnetic properties of soft-magnetic wound cores are usually assessed by means of an indirect measurement principle where a test specimen is equipped with two windings. With the first having NP turns, an appropriate magnetic field strength is established in the specimen due to a primary current, whereas with the second with NS turns, a magnetic flux density is calculated based on the induced voltage. The paper focuses on evaluation of measurement results obtained using two measurement approaches. The first one requires that a specimen is magnetized with such primary current that the induced voltage on the secondary side and therefore also the magnetic flux density in the core is sinusoidal. The second one, on the other hand, requires a sinusoidal primary current causing a sinusoidal magnetic field strength. As discussed in the final section, both principles serve for a complete insight into magnetic properties of the material, thus providing crucial information during the magnetic design of the final product.
COBISS.SI-ID: 11672148
An electrostatic simulation of a single stator slot using finite-element method was made in order to calculate the capacitance between stator winding and stator frame. Additional calculations of the capacitance were made, where the slot conductors were dislocated from their original position, which resulted in higher capacitance. The simulation was confirmed with measurements. Both were performed on the example of the in-wheel direct drive motor. Common-mode current transient phenomenon, caused by inverter switching operation, was simulated.
COBISS.SI-ID: 11605588