Series Switch Research Articles

The Effect of Series and Shunt Redundancy on Power Semiconductor Reliability

In different industrial and mission oriented applications, redundant or standby semiconductor systems can be implemented to improve the reliability of power electronics equipment. The proper structure for implementation can be one of the redundant or standby structures for series or parallel switches. This selection is determined according to the type and failure rate of the fault. In this paper, the reliability and the mean time to failure (MTTF) for each of the series and parallel configurations in two redundant and standby structures of semiconductor switches have been studied based on different failure rates. The Markov model is used for reliability and MTTF equation acquisitions. According to the different values for the reliability of the series and parallel structures during SC and OC faults, a comprehensive comparison between each of the series and parallel structures for different failure rates will be made. According to the type of fault and the structure of the switches, the reliability of the switches in the redundant structure is higher than that in the other structures. Furthermore, the performance of the proposed series and parallel structures of switches during SC and OC faults, results in an improvement in the reliability of the boost dc/dc converter. These studies aid in choosing a configuration to improve the reliability of power electronics equipment depending on the specifications of the implemented devices.

Optimization of structures of DC RF MEMS series switches for low actuation

This paper presents the design and simulation of low actuation DC RF MEMS ohmic series switches. The proposed switches are suitable for applications to be used in the frequency range from DC to 10 GHz. Therefore these switches can be used for satellite communication and other microwave communication applications. The structure of the series switch is designed to obtain low pull-in voltages in the range of 6–14 V. The switches are simulated in CoventorWare while the RF characteristics are extracted using ANSOFT HFSS. The results show low insertion loss in the range of 0.005 to 0.06 dB and high isolation in the range of −70 to −76 dB.

Linear Regulator Design Considerations of the Serial Linear-Assisted Switching Converter Used as Envelope Amplifier

Envelope elimination and restoration technique and envelope tracking technique are proposed to enhance efficiency of radio frequency power amplifier (RFPA), and both of them take envelope amplifier (EA) as a high slew-rate variable voltage source. Serial linear-assisted switching converter, one of the solutions of EA, has benefits in high tracking bandwidth, high tracking accuracy, and relatively low switching losses. Among those many types of linear-assisted switching converter, the design of a linear regulator is rarely mentioned. This paper proposes a new design of linear regulator to supply a higher voltage and maintain high tracking bandwidth by dividing a linear regulator into four different parts. Beyond that, an input filter is recommended to increase the power supply rejection ratio (PSRR) of a linear regulator in high frequency, which is able to reduce the glitch caused by multilevel voltage power supply. An EA prototype is composed of the proposed linear regulator, the PSRR improvement filter, and the multilevel voltage power supply. To align signals, circular convolution is suggested as a modified algorithm. Experiments show that this prototype has a maximum output of 40 V, a tracking bandwidth of about 2 MHz for a full-range sinusoidal signal, and a tracking ability for OFDM envelope signal with a subcarrier up to 5 MHz.

A Disparate Low Loss DC to 90 GHz Wideband Series Switch

A Disparate Low Loss DC to 90 GHz Wideband Series Switch

Using qualitative approach to forecasting regime switches

Drastic changes (named regime switches) often exist in economic and financial time series causing the forecasting of time series difficult. Hence, we need robust models to detect and forecast the regime switches. Most previous studies apply quantitative methods to forecast time series and regime switches. Contrast to these studies, this study attempts a novel approach to use a qualitative method to forecast regime switches. Fuzzy set/qualitative comparative analysis (fsQCA), based on fuzzy set and logic theory, yields the relationships between antecedent combinations and outcome. Studies support fsQCA analysis is more proper to reflect the real situations. Hence, this study uses fsQCA to analyze the autoregressive relationships of the upward and downward regime switches in the in-sample data. Then, the relationships are used to forecast the regime switches in the out-of-sample data. Taiwan Capitalization Weighted Stock Index is taken as the data for analysis. The empirical results show that fsQCA provides strong predictive validities.

Slightly Independent and Illegal: Yaima Pardo’s films OFF_LINE and SWITCH ON at the Crossroads of Literacy, Inclusion and Digital Filmmaking in Contemporary Cuban Cinema

Cuban filmmaker Yaima Pardo creates a participatory digital literacy campaign in her documentary OFF_LINE (2013) and documentary series SWITCH ON (2013-present). Through her work she establishes a multi-directional dialogue on digital literacy. Beyond this call for digital literacy, Pardo herself is part of a contemporary generation of Cuban filmmakers, nuevos realizadores that depend on digital technology to make, distribute and exhibit their works despite their illegal status as the Cuban state does not recognize their independent production companies. Challengingover fivedecades of control, Pardo and her peers are part of a larger national fight to redefine Cuban film.

Stop-Loss Strategies with Serial Correlation, Regime Switching, and Transactions Costs

Stop-Loss Strategies with Serial Correlation, Regime Switching, and Transactions Costs

Identifying regime switches using causal recipes

This study proposes a new method to identify regime switches in a time series. First, the method uses fuzzy set/qualitative comparative analysis (fsQCA) instead of quantitative methods because studies show that fsQCA outperforms quantitative methods. The new method is unique in that the method examines causes for regime switches instead of outcome as in previous studies. FsQCA explores the relationships between relevant antecedents of energy consumption and gross domestic product as the outcome. Historical events validate the results, which demonstrate that the method successfully identifies regime switches.

Analysis and Design of a Modular Multilevel Converter With Trapezoidal Modulation for Medium and High Voltage DC-DC Transformers

Conventional dual-active bridge topologies provide galvanic isolation and soft-switching over a reasonable operating range without dedicated resonant circuits. However, scaling the two-level dual-active bridge to higher dc voltage levels is impeded by several challenges among which the high dv/dt stress on the coupling transformer insulation. Gating and thermal characteristics of series switch arrays add to the limitations. To avoid the use of standard bulky modular multilevel bridges, this paper analyzes an alternative modulation technique, where staircase approximated trapezoidal voltage waveforms are produced; thus, alleviating developed dv/dt stresses. Modular design is realized by the utilization of half-bridge chopper cells. This way the analyzed dc-dc transformer employs modular multilevel converters operated in a new mode with minimal common-mode arm currents, as well as reduced capacitor size, hence reduced cell footprint. Suitable switching patterns are developed and various design and operation aspects are studied. Soft-switching characteristics will be shown to be comparable to those of the two-level dual-active bridge. Experimental results from a scaled test rig validate the presented concept.

Design and modeling of a novel RF MEMS series switch with low actuation voltage

This paper presents the design, analysis, modeling and simulation of a novel RF MEMS series switches with low actuation voltage. A mechanical modeling is presented to describe the behavior of the series switch. The switch is designed with special mechanical structures. The novel mechanical and mathematical modeling of the switch leads to calculation of the accurate actuation voltage. The spring constant has been calculated in relation to the presence of the residual stress in the beam. The calculated spring constant for this beam is used to determine the accurate actuation voltage. The size of the switch is 60 ? 110 µm2. The designed RF MEMS series switch was simulated using Intellisuite MEMS tool. He calculated actuation voltage is 4.05 V and simulated one is 4.2 V for 0.6 µm beam thickness. The calculated result is also very close with simulated one. The proposed switch compared with other electrostatic switches has low actuation voltage and small size. The RF characteristics were simulated using HFSS software and the switch has good RF performance. The insertion loss of 0.067 dB, return loss of 26 dB and isolation of 16 dB were achieved at 40 GHz.

A high-power nanosecond pulse generator based on a serial wave summator and transistor switches

A high-power nanosecond pulse generator based on a serial (linear) radial-coaxial summing structure and primary partial pulse formers, which are based on high-speed IGBT transistors, is described. The generator has a modular structure in the form of a system of serially connected sections. Each section ensures generation and matched transmission of partial rectangular pulses having a duration of 40–200 ns, a power of 10 kW–1.5 MW, and a voltage of 0.1–1.2 kV with a pulse repetition rate of up to 2 kHz to a summing coaxial waveguide. The generator output parameters are determined by the number of connected sections. The three-section generator, intended for producing rectangular nanosecond pulses with a power of up to 3.5MW, was designed, manufactured, and tested.

Miniatured Phase Shifter

Objective: RF MEMS has emerged as a technology with immense potential for wireless communication and defence applications. In this work, a 5 bit RF MEMS switched line phase shifter is presented using cantilever switch achieving low actuation voltage. Methodology: In this work 5 different phase shifters are designed to get 5 bit phase shift at a particular frequency 10 GHz. The phase shifters consist of stubs like structure designed in the ground of CPW and MEMS capacitive series switches. Solid-state phase shifters based on p-i-n diodes or Field-Effect Transistor (FET) switches are used because they provide a good planar solution at a variety of microwave frequency ranges. Micro Electro Mechanical Systems (MEMS) phase shifters are progress today are mainly have established designs because of which the solid-state switch is replaced by a MEMS switch. Findings: By analysing theoretically and practically the results showed that a novel RF MEMS switch was capable of liberating less than 0.1dB insertion loss and more than 19 dB isolation between input and output ports at 20 GHz .This RF MEMS switch shows a 5V actuation voltage. Switching time of RF MEMS switches is measured using a theoretical approach. The switches demonstrated maximum switching time of 0.1μs. By using this switch a 5-bit miniaturized phase shifter is designed i.e. 180° bit, 90°, 45°, 22.25° and 11.5° bits were achieved using the switched line type phase shifters at 10 GHz. A novel switched line type phase shifter loaded with multiple switch pairs was developed and was capable of liberating a multiple phase shift angles within single design

A 24 GHz reflective-type phase shifter with constant loss in 0.18 μm CMOS technology

With the aim of achieving constant insertion loss, this paper presents the design of a 24GHz reflective-type phase shifter (RTPS) integrated with a switched Π-attenuator for phased array transmitters. Three RTPS circuits with hybrid coupler and capacitive-type reflective loads are cascaded to obtain required phase-shift. Accumulation-mode MOS (AMOS) varactors are used as reflective loads for phase control. In order to achieve a compact scheme, the hybrid couplers are designed using lumped elements. A switched Π-attenuator is used in front of the RTPS for gain control. Body switching technique is applied in series switch of the Π-attenuator to improve its switching performance. Consuming zero DC power, the proposed circuit demonstrates a maximal relative phase-shift range of 185°, a constant insertion loss of 10.7dB, and a worst-case input return loss better than 15dB at 24GHz. The circuit is implemented in a standard 0.18μm CMOS technology and the post-layout simulation results are reported.

Reducing Switching Losses in BLDC Motor Drives by Reducing Body Diode Conduction of MOSFETs

This paper presents a new power electronic topology that aims to reduce switching losses in hard-switched inverters for brushless dc (BLDC) motor drives. This is achieved by extending the benefits of synchronous rectification used in low-voltage switch-mode dc-dc conversion to high-voltage motor drive applications and by minimizing the reverse conduction behavior of the intrinsic body diode of the synchronous rectifier MOSFET. The proposed topology for reducing body diode conduction includes the addition of a MOSFET in series with the rectifying switch and a SiC Schottky diode around the series switch combination. This paper focuses on theory, simulations, and experimental results and validates the benefits of proposed new topology for BLDC motor drive applications. An extension of this topology for sinusoidal back electromotive force permanent-magnet motors is also presented.

Design and numerical investigation of A HVDC vacuum switch based on artificial current zero

With the fast development of multi-terminal high-voltage direct-current (HVDC) transmission technology, there is an urgent demand for the HVDC interruption technique. In this paper, an interruption scheme for HVDC based on artificial current zero is proposed with its main circuit breaker consisting of modularized vacuum switch in series. A triggered sphere gap is adopted as the commutation switch to achieve bidirectional DC interruption. The interruption process, particularly, the most important two commutation processes, is simulated based on a circuit model. The residual current and its influence after current commutation, which might exist due to the weak arc extinguishing capacity of the sphere gap, are analyzed. It is proposed to use back-up circuit breakers to interrupt the residual current. Furthermore, the influence of the frequency of the countercurrent on the interruption process, particularly, on the integral of i <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> t in the triggered sphere gap due to the residual current, is discussed.

Comparative Study of Perforated RF MEMS Switch

Abstract MEMS are the Micro Electronic mechanical system or in general terms it is also known as Micro electronic mechanical switch. MEMS have classified in two types of switch that is series switch and shunt switch .The cantilever is a series type switch whereas the fixed- fixed beam is shunt type switch. Fixed- Fixed beam is the element that is fixed at both anchor ends. The electrostatic actuation process occurs on the switch due to which switch deflects from its original position. The stiction problem occurs in MEMS switches which have been reduced by the proposed design. The perforation is used to reduce the squeeze film damping by decreasing the mass of the switch. As the voltage increases the switch moves to downward z-direction .The displacement is produced in the switch as direction of movement is towards negative z-axis. When the beam contacts with electrode, pull in voltage is achieved. This paper explores the perforation and meander concept with Fixed -fixed switch, which increases the flexibility, low actuation voltage and switching speed. The various types of perforations provide discrete displacement corresponding to voltage. In this paper we represent the design and simulation of Fixed-Fixed switch using perforation of size 2 μm-5 μm. The electrostatic actuation mechanism is applied on the Fixed-fixed switch which has a serpentine meanders and perforation at different voltages. The switch is designed and simulated by using COMSOL®MULTIPHYSICS 4.3b software.

Is Switzerland an Interest Rate Island after All? Time Series and Non-Linear Switching Regime Evidence

Has the 'Swiss interest rate anomaly' persisted after the financial crisis? Regarding the hypothesis that the Swiss interest rate anomaly results from systemic risk anticipation, we discuss whether Switzerland remains an interest rate island in the wake of the financial crisis. We find evidence for the demise of the interest rate bonus of the Swiss franc (CHF) vis-a-vis the Euro (EUR) after the Swiss National Bank (SNB) started to advocate an exchange rate floor with the Euro. After the compression of the bonus to insignificant levels, the uncovered interest parity (UIRP) holds again. We find evidence for a recent regime switch after the SNB has discontinued the exchange rate floor with the Euro.

Improving network intrusion detection system performance through quality of service configuration and parallel technology

This paper outlines an innovative software development that utilises Quality of Service (QoS) and parallel technologies in Cisco Catalyst Switches to increase the analytical performance of a Network Intrusion Detection and Protection System (NIDPS) when deployed in high-speed networks. We have designed a real network to present experiments that use a Snort NIDPS. Our experiments demonstrate the weaknesses of NIDPSs, such as inability to process multiple packets and propensity to drop packets in heavy traffic and high-speed networks without analysing them. We tested Snort's analysis performance, gauging the number of packets sent, analysed, dropped, filtered, injected, and outstanding. We suggest using QoS configuration technologies in a Cisco Catalyst 3560 Series Switch and parallel Snorts to improve NIDPS performance and to reduce the number of dropped packets. Our results show that our novel configuration improves performance.

Analysis on the Wind Turbines Current Influenced by the Impedance Variation of Low Voltage Ride through Test Device

To analysis the low voltage ride through tests results carried out in Inner Mongolia, the impedance model of low voltage ride through test equipment ability with the wind turbine is established. The grid current variation caused by series or parallel impedance switching is analyzed theoretically. Results show that grid current will become larger while the parallel impedance of low voltage test equipment is smaller. Consequently, suggestion is proposed to take optimal configuration of impedance in the equipment to reduce effect on grid current, which can ensure the smooth running of low voltage ride through test.

Finite element modeling of a Ti based compact RF MEMS series switch design for harsh environment

Regardless of the excellent RF characteristics that microelectromechanical switches possess in variety of high frequency applications, some of these application areas require switches that could possibly withstand harsher environments like high temperature or high thermal stresses. This paper presents the finite element modeling of a compact RF MEMS DC contact switch design based on titanium material to withstand in such conditions. The switch is designed with meanders on all sides to increase the elastic recovery forces. The proposed switch dimensions are very compact with the total surface area of 0.1 mm$$^2$$2. The modelled switch is optimized for L-band that results in high isolation of 52 dB and very low insertion loss of 0.007 dB at 2 GHz with low actuation voltage of 18.5 V.