The matrix rectifier modulated by the classical space vector modulation (SVM) strategy generates common-mode voltage (CMV). The high magnitude and high du/dt of the CMV causes serious problems such as motor damage, electromagnetic noise and many others. In this paper, an improved SVM strategy is proposed by replacing the zero vectors with suitable couple of active ones that substantially eliminate the CMV. Theoretical analysis proves that the proposed strategy can reduce the amplitude of the CMV to half of the original value. In addition, the quality of the input and output waveforms is not affected by extra active vectors. Simulation and experimental results demonstrate the feasibility and effectiveness of the proposed strategy are shown.
The paper presents a methodology for the optimization of a Brushless Direct Current motor (BLDC). In particular it is focused on multiobjective optimization using a genetic algorithm (GA) developed in Matlab/Optimization Toolbox coupled with Maxwell from ANSYS. Optimization process was divided into two steps. The aim of the first one was to maximize the RMS torque value and to minimize the mass. The second part of the optimization process was to minimize the cogging torque by selecting proper magnet angle. The paper presents the methodology and capabilities of scripting methods rather than specific optimization results for the applied geometry.
The optimization method using the ON/OFF sensitivity analysis has an advantage hat an epoch-making construction of magnetic circuit may be obtained. Therefore, it is attractive for designers of magnetic devices. We have already developed the ON/OFF method for the optimization of a static magnetic field problem, and the effectiveness is verified by applying it to the optimization of magnetic recording heads. In this paper, the ON/OFF sensitivity method is extended to the optimization of the eddy current problem using the adjoint variable. The newly developed ON/OFF method is applied to the determination of the optimal topology of the yoke of the billet heater for rolling wire rod. As a result, the optimal shape of yoke, which we could not imagine beforehand can be obtained. It is shown that the local heating of the yoke was reduced without decreasing the heating efficiency.
This work summarizes efficiency measurement results of a full bridge, 3 phase inverter composed of state-of-the-art Si IGBT transistors and Si or SiC diodes. Different (symmetrical and discontinuous) space vector modulation strategies were chosen in order to examine their influence (together with modulation frequency) on inverter losses. Induction machine was used as load, different load points were examined. Results clearly show, that proper modulation strategy, minimizing the switching losses of semiconductor switches, can increase the overall output efficiency at about 1% in case of both silicon and hybrid constructions. The drawback of DPWM approach is connected with the decreased quality of inverter output current. Hybrid technology can also improve the output efficiency at about 1% when compared to traditional constructions, but only in case of elevated switching frequencies. At low frequencies (below 10 kHz) modern semiconductor offer comparable results at much lower device costs.