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In high-power converters based on SiC-MOSFET half-bridge modules, laminated busbar plays a critical role in linking the DC capacitor bank to power modules. The busbar stray capacitance has the same order of magnitude with drain-source capacitance of SiC-MOSFET and has a great impact on the turn-off voltage oscillation of SiC-MOSFET. In this paper, parasitic elements of a three-layer laminated busbar...
Voltage deviations of dc-link capacitors are the main problem of multilevel diode-clamped converters (DCC). In this paper, a novel carrier-based voltage balance method is proposed to balance the dc-link capacitors of five-level DCCs. The proposed method is characterized by injecting proper zero-sequence voltages in the modulation signals of carrier-based modulators. The effects of the injected zero-sequence...
Voltage Balance of the series-connected dc-link capacitors is the key problem of three-level diode-clamped converters. In this paper, an auxiliary voltage balance circuit (VBC) is presented to maintain the voltage balance of dc-link capacitors. The voltage balance circuit consists of a clamping capacitor and a current-limiting inductor. With the clamping capacitor, the voltage stresses of the auxiliary...
In order to obtain an effective control range analysis method of different capacitor voltage balancing control strategies, this paper proposes a control range analysis method based on virtual loss difference resistance model. In this paper, the virtual loss difference resistance model is established on the submodules of cascaded converters. The control ranges of several conventional capacitor voltage...
This paper discusses the dead-time effect of dual bridge series resonant DC/DC converter (DBSRC). The phase-shift modulation is usually adopted in DBSRC. However, the phase-shift angle is usually small, and voltage polarity reversal (VPR) may occur in dead-time, which may deteriorate EMI/EMC and increase loss. This paper analyzes the commutation of DBSRC when VPR occurs and proposes a method to eliminate...
In order to eliminate the common-mode (CM) leakage current in the transformerless photovoltaic (PV) systems, the concept of the virtual dc bus is proposed in this paper. By connecting the grid neutral line directly to the negative pole of the dc bus, the stray capacitance between the PV panels and the ground is bypassed. As a result, the CM ground leakage current can be suppressed completely. Meanwhile,...
The increased penetration of electronic loads in distribution systems results in more frequently occurring problems for the utilities due to triplen harmonics - a trend that has been confirmed in a recent utility survey conducted as part of DSTAR project 13–5. In this paper, we investigate an inexpensive mitigation option that has been recently applied successfully on an actual distribution feeder...
Capacitors have long been used on distribution feeders for, among other things, voltage profile management, power factor correction and loss reduction. The basic choice has been: fixed banks; or switched banks with a variety of local controls. Centralized Volt/VAR control allows for “optimal” feeder conditioning for loss reduction and demand reduction. To be effective, both local and centralized control...
In the transformerless photovoltaic (PV) system, the common mode ground leakage current may appear due to the galvanic connection between the PV array and the ground, which causes the safety issues and reduces the efficiency. To solve this problem, a novel inverter topology with switched capacitors is proposed in this paper. By connecting one pole of the PV cell directly to the neutral line of the...
In this paper, a zero voltage transition (ZVT) interleaved high step-up converter with built-in transformer and voltage doubler for photovoltaic (PV) grid-connected generation system is proposed. The built-in transformer and the voltage doubler are employed to extend the voltage gain, reduce the switch voltage stress, which makes the low on-resistance switch can be adopted to reduce the conduction...
Described in this paper is a new Microelectromechanical Hybrid Gyroscope (MHG), with advantages not only in the potentiality of achieving the high precision like the traditional dynamically tuned gyroscope (DTG), but also in small size and low cost like the Silicon Micromachined Gyroscope (SMG). The transfer coefficient of the moment is derived, with influence factors analyzed. A new tuning method...
With worldwide increasing focus on energy efficiency, conservation, and demand reduction, technical losses are under intense scrutiny among power utilities. A critical issue is to understand where technical losses occur and how they may be most effectively mitigated. This paper investigates technical loss on typical U.S. feeders as a function of feeder configuration, e.g. feeder length, load density,...
A high step-up converter with a coupled inductor and a switched capacitor is proposed in this paper. By using the coupled inductor, the voltage gain of the converter is extended and the voltage stress of the main switch is decreased to reduce the conduction losses. Moreover, the reverse-recovery problem of the output diode is alleviated by the leakage inductance. By using the switched capacitor, the...
In this paper, a low power receiver utilizing a resonant transformer circuit at 20 GHz to decrease the antenna/system sizes to meet the smart dust system (SDS) millimeter size space requirement was designed. The resonator transformer generates relatively large voltages and facilitates diode-based demodulation. The receiver was designed for low power SDS applications at 20 GHz. The chip has been taped...
We report a novel polymer-ceramic composite of high dielectric constant for embedded capacitor application. The low cost polymeric matrix was benzoxazine resin and the high constant ceramic filler for the polymer composite was BaTiO3. The benzoxazine/BaTiO3 composite was prepared by the method of mixing. The dielectric constant, dissipation factor, volume resistivity and breakdown voltage of the...
A new three dimensional space vector modulation (3D-SVM) strategy in abc coordinates for the three phase four wire converter with split-capacitor is presented. Among various three phase four wire converters, the center split converter is suit to low cost, low power applications for its fewer switches. Compare to the 3D-SVM in alphabetagammacoordinates, the strategy in abc coordinates is more clearly...
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