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A zero voltage switching space vector modulation (ZVS-SVM) controlled three-phase boost rectifier is proposed. A branch composed of one active switch, one resonant inductor and one clamping capacitor is added to the six-switch boost rectifier. In addition, a ZVS-SVM for the rectifier is proposed. It can effectively suppress the reverse recovery process of the bridge switch anti-parallel diodes. All the switches are turned on under zero voltage condition, thus the switching loss is reduced, and electromagnetic interence can be lowered. The switching frequency of the rectifier is fixed. The auxiliary switch works at the same frequency with other switch. All the switches in the rectifier have lower voltage stress. A digital signal processor controlled 4-kW prototype is built to verify the theory. Index Terms-Electromagnetic interference (EMI), power factor correction (PFC), zero voltage switching space vector modulation (ZVS-SVM).

Keywords: 12-pulse hybrid rectifier, sinusoidal input current, controlled output voltage, aircraft applications Passive rectifiers are advantageous compared to active rectifiers concerning efficiency, low complexity, EMC, and reliability. Furthermore, for high input frequency applications, such as aircraft and micro gas turbine systems, the magnetic components occupy a smaller volume. On the other hand, hybrid rectifiers can compensate drawbacks of passive rectifiers such as ensuring a controlled output voltage. In this paper, a novel control scheme of the hybrid rectifier is proposed for achieving purely sinusoidal input currents. Furthermore, the control scheme is verified with numerical simulations and experimental results.The main circuit configuration of the hybrid rectifier, which composes a voltage-type 12-pulse passive rectifier and DC-DC converters, is shown in Fig. 1. The output voltage can be controlled by the power transistors T 1 and T 2 . The input current shape depends on only the output voltages of the diode bridges and the turns ratio (w B /w A =0.366) of the line interphase transformers (LIT). The input currents can therefore be controlled by using variable duty cycles of T 1 and T 2 . From space vector equations the optimum voltage modulation in order to achieve purely sinusoidal input currents can be derived aswhere u 1 and u 2 are the local average values of voltages across Fig. 1. Novel hybrid 12-pluse LIT rectifier with controlled output voltage and purely sinusoidal input currents T 1 and T 2 respectively andû is the peak input phase voltage. The waveforms u 1 and u 2 are close to having a trianglar shape that that varies between zero and the output voltage for the angleThe triangular shape can be realized by changing duty cycle of T 1 and T 2 . Fig. 2 shows the experimental input currents of a 10 kW prototype controlled by the conventional constant duty cycle (a) and by triangular modulation (b), which approximates well u 1 and u 2 according to (1). By applying the proposed modulation scheme, sinusoidal input currents are realized. The THD is reduced from 6.1% to 2.0% and the power factor is improved from 0.968 to 0.976. The input inductor L is designed to fulfill the requirements of low-order input current harmonics for aircraft applications. Since low-order input current harmonics can be significantly reduced by the proposed control scheme, the inductance of L can be reduced. However, the flux density through the LIT is increased if the proposed control scheme is applied.In this paper a novel control scheme to achieve purely sinusoidal input currents for a voltage-type hybrid 12-pulse rectifier has been proposed. In further work, the application of the control scheme will be studied for current-type multi-pulse hybrid rectifier systems. MemberA novel injection scheme to improve the input current harmonics of a hybrid 12-pulse line-interphase-transformer rectifier with controlled output voltage by a two-switch boost-type output stage is presented in this paper. A theoretical derivation...

Integrated electromagnetic interference (EMI) filter design method with flexible multilayer (FML) foils is presented. An analysis model for integrated EMI filter with FML foils, distributed electromagnetic component (DEMC) model, is proposed. The DEMC model is verified by the experiment. In addition, method to improve the high-frequency performance of integrated EMI filter is investigated. Prototype of integrated EMI filter with FML foils is made for 1 kW switching power supply. In comparison with the traditional discrete EMI filter, it can reduce total volume by 45%.Index Terms-Electromagnetic interference (EMI) filter, flexible multilayer (FML) foil, model, passive integration, power density.