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In this article, the arm phase-shift conducting modulation (PSCM) is proposed for the alternate arm multilevel converter (AAMC). With the PSCM strategy, the half-bridge (HB) structure could be applied as the submodule (SM) topology to reduce the circuit complexity of the full-bridge submodule based AAMC. First, the phase-shift angle is introduced to match the voltage modulation ratio and power factor of ac grid. The energy stored in the submodule capacitors are balanced by regulating the phase-shift angle. Then, the design criteria and operation performance for HBSM-AAMC with the proposed PSCM strategy are analyzed and presented. Compared with HBSM-modular multilevel converters (MMC), 18% HBSMs and 9% power devices are reduced with the proposed topology and modulation, resulting in the lower construction cost. Furthermore, the loss distribution is analyzed, and the operating losses of HBSM-AAMC are smaller than that of HBSM-MMC. Finally, the simulation and experiment are performed to verify the effectiveness of the derived topology and the proposed modulation strategy.

Phase-change random access memory with an ovonic threshold switch (OTS-PRAM) has become increasingly popular as an alternative to resolve the problem caused by the small capacity of dynamic random access memory and the high latency of NAND flash memory in computing systems. However, an OTS has a temperature-dependent OFF-current ( $I_{\mathrm {off}}$ ) and threshold voltage ( $V_{\mathrm {TH}}$ ). This causes $I_{\mathrm {off}}$ of a cell ( $I_{\mathrm {off\_{}CELL}}$ ) and $V_{\mathrm {TH}}$ of a cell ( $V_{\mathrm {TH\_{}CELL}}$ ) to become temperature-dependent, inducing a sensing error during read operations. In this article, an adaptive sensing voltage modulation (ASVM) technique is proposed that adaptively controls the bitline and wordline voltage depending on the change in temperature to compensate for the temperature-dependent variation in voltage drop caused by $I_{\mathrm {off\_{}CELL}}$ and $V_{\mathrm {TH\_{}CELL}}$ . The HSPICE simulation results, with an industry-compatible 250-nm complementary metal–oxide–semiconductor process for the 20-nm PRAM technology, show that the OTS-PRAM with the proposed ASVM can achieve a bit error rate below 0.1 ppm within the operating temperature range of 0 °C–85 °C.

A plasma-based ferroelectric undoped HfO x capacitor is fabricated using plasma-enhanced atomic layer deposition (PE-ALD), and the multilevel characteristics of synaptic behavior are investigated. A gradual ferroelectric phase transition in the material is confirmed by grazing incidence X-ray diffraction (GI-XRD) for different O2 plasma periods. The metal–ferroelectric–metal (MFM) capacitor presents excellent remnant polarization ( ${\text{P}}_{r}$ ) up to $13~\mu \text{C}$ /cm2 and a switching endurance of more than 108 cycles. Superior small potentiation/depression nonlinearity ( $\alpha _{p}/\alpha _{d} = -0.08$ /−1.66 for voltage modulation stimulation) for synaptic training and almost symmetry training curve ( $\vert \alpha _{p}$ - $\alpha _{d}\vert $ ) are obtained. High stability under multilevel operation with five consecutive cycles of alternating potentiation and depression is exhibited without significant polarization variation for each training step (pulse).

Oxygen electromigration applied to a YBa2Cu3O 7 − δ nanowire can be used to tune its electrical properties. Here, we apply electromigration to YBCO nanowire-based superconducting quantum interference devices (SQUIDs) and study its effect on the voltage modulation depth of the devices. Using a dc electromigration current we replenish the oxygen of the weak links, improving the critical current symmetry of the SQUIDs. AC current electromigration is used to reduce the doping level of the weak links, thus reducing their critical current and increasing differential resistance. Both type of electromigration processes are found to improve the SQUIDs performance, although the best results are obtained with ac biased electromigration, which improved the voltage modulations of the SQUIDs by a factor as high as 8. This procedure can be instrumental to fine tune ex-situ the properties of superconducting electronics where a large number of weak links are required.

With the people's health requirements and the development of industry, the electrostatic precipitator is widely used in many industrial areas, such as smelting, cement production, electric boilers and so on, as well as in household air purification. In order to improve the frequency of the converter and reduce the switching loss, a phase shift voltage control method based on PID control is introduced in this paper. A serious of problems are also be solved by the method, such as the uncertainty of electrostatic precipitator load, the characteristics of nonlinear and time-varying, and the uncertainty of stray parameters of high frequency transformer which is the core device of the electrostatic precipitator power supply. This method can make use of the stray parameters of high frequency transformer reasonably, so that the power device can work in soft switching state. In the same time, it is suitable for industrial mass production with lower cost but good effect. The results of simulations and experiments show that this voltage modulation mode makes the dusting power supply output 60 kV voltage stably, and has good dynamic performance, which makes the dust removal system more robust.

This paper proposes the simple fault tolerant control for stable operation through fault-tolerant switching combination in the case of switch faults for active neutral point clamped (ANPC) multi-level-inverter. The proposed scheme is a countermeasure and control under the fault condition of power switch devices in ANPC configuration through switching reconfiguration and simple reference control. The proposed scheme can control the stable operation through the switching combination without any additional switch or device under fault condition in the multi-level structure. The reliability and robustness of multilevel inverter, therefore, are improved by the proposed scheme. The feasibility of the proposed fault tolerant control scheme is confirmed by simulation results.

A zero-sequence circulating current (ZSCC) is typically generated among the multiparallel converters that share the common dc link and ac side without isolated transformers under the space vector modulation (SVM), due to the injected third-order zero-sequence voltage (ZSV). This paper analyzes SVM techniques, studies the effects of the ZSV on the ZSCC control loop in detail, and then proposes an improved SVM scheme to suppress the impact of the ZSV on the ZSCC. The proposed strategy can effectively realize the ZSCC suppression, even though the parallel converter modules have asymmetrical current references and filter inductances. The simulation and experimental results based on the parallel converters clearly verify the effectiveness of the proposed control.

This work proposes a technique to inject a discontinuous zero sequence signal (D-ZSS) into voltage modulation of the modular multilevel converter arms. The core of the technique is the clamping of the arm voltages to a particular level and interval, in such a way that reduces the number of switching events on the instants that the load stress on the semiconductors is high, and consequently the dissipated energy. The clamping voltage and interval has some degrees of freedom which are also discussed. The description of the methodology is complemented with its simulation. Either in steady-state or in dynamic converter operation this technique is able to reduce the switching events and the correspondent total losses up to 6.6%. Hence contributing to a more efficient VSC-HVdc solution.

This study was launched to demonstrate that LEDs at zero bias show recombination photon emissions, and to check the models for the same. A method for measuring the light emission for a LED near zero bias is presented. A large reverse bias sufficient to suppress detectable emissions is assumed. The bias voltage between &lsquo, large reverse&rsquo, and our target voltage is modulated, and the difference measured. The measured emissions found are consistent with the Shockley diode equation. The spectrum near zero bias can be measured and characterized. It shows LED behavior that is substantially different from other typical measurements, and suggests a violation of Kirchhoff&rsquo, s Law.

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The performance of high T/sub c/ SQUIDs with resistively shunted inductances have been investigated. We find that the voltage modulation depth /spl Delta/V of shunted 83 pH SQUIDs is significantly larger than that of unshunted SQUIDs with similar parameters and increases with the parameter /spl gamma/=R/sub n//R/sub s/ as expected from theory (R/sub n/ is the junction resistance and R/sub s/ the shunt resistance). We also find that the conventional decrease of /spl Delta/V with SQUID inductance L can be eliminated leaving only the effect of the thermal noise flux. In this way /spl Delta/V=63 /spl mu/V has been achieved for a bicrystal SQUID at 77 K whose screening parameter /spl beta//sub L/=13. Noise measurements performed on this SQUID indicate that the resistor in circuit does not increase the noise.

Three possible strategies to achieve Fault Ride-Through of offshore wind farms connected through voltage-sourced converter (VSC) based HVDC links are investigated in this paper. Dissipation of excess energy by a braking resistor, fast wind power reduction by voltage modulation and a combination of these two are analyzed. The studies are performed in a four-terminal HVDC grid connecting two 1000 MW wind farms comprised of variable-speed full scale converter wind turbines. Simulation results demonstrate improvements in the performance of the synergistic approach (coordinated operation of the first two strategies). This type of analysis can aid in the design of cost-effective FRT schemes of the envisioned HVDC multiterminal systems.

Present electronic ballast with dimming controls all share one disadvantage, the stability of the lamps changes as the dimming level changes. Therefore, a dimming stabilization method using both frequency modulation and voltage modulation is proposed here to remedy the aforementioned shortcoming. This technology makes the dimming range of gas-discharge lamp wider and lets the lamp maintain a stable lighting state within the whole dimming range. From the standpoints of both theoretical reasoning and practical test results, the proposed method overcomes the problem of dimming instability.

In this study, we would like to tune the color temperature of the high power phosphor Light-Emitting Diodes (LEDs) with the single LED of red, green, yellow and blue, respectively. The starting color temperature of the white phosphor LED will be set at 7500K (D75 white light), then changing the voltage of the single LED of the red, green, yellow and blue, respectively, to find the best tuning function for the color temperature and luminous efficiency. These results exhibited that changing the voltage of red LED had the broader color temperature from 7500 K to 1500 K and low luminous variation from 54 to 41 lm /W than green and blue LEDs. Though the green and yellow LEDs had the low luminous variation from 47 to 51 lm /W and from 40 to 47 lm /W, respectively, but the color temperature of green and yellow LEDs could only fine turn from 7500K to 8200K and 4700K to 7500K, respectively. The luminous efficiency had rapid variation from 27 to 42 lm /W and out of the color temperature of 20000K for the voltage tuning of blue LED. Therefore, the voltage tuning of red LED could show the warm color temperature for the human life. The variation of color shifts (Δuv) of red and green LEDs changed from small to large with the increasing of the enhanced voltage. But the variation of Δuv of the yellow and blue LED changed nothing with the increasing of the enhanced voltage.

Recent submicron DC GaAs MESFET models (Ahmed et al., IEEE Trans. Electron. Devices, ED-44 (1997) 360) are improved in order to more accurately facilitate non-linear small-signal circuit designs. The Ahmed–Ahmed–Ladbrooke (AAL) model (Ahmed et al., IEEE Trans. Electron. Devices, ED-44 (1997) 360), allowed for the prediction of the DC characteristics of large-signal submicron devices by using the concept of a shift in threshold voltage. The new model proposed in this paper uses a small number of variables and, while improving on the AAL model, retains the essential form of the more common Curtice and Advanced Curtice models (Curtice, IEEE Trans. Microwave Theory Tech., MTT-28 (1980) 4456; de Graaff and klaassen, Compact Transistor Modelling for Circuit Design, Springer, Vienna, 1990) together with accounting for gate-source voltage modulation effects.

A new approach to the fabrication of a SrTiO/sub 3/ bicrystal substrates, based on floating zone growth of natural SrTiO/sub 3/ bicrystals with misorientation angles 24/spl deg/ and 37/spl deg/, has been developed. Thin film YBCO Josephson junctions and dc SQUIDs on SrTiO/sub 3/ bicrystal substrates were fabricated and studied at T=77 K. The critical current density j/sub c/ and I/sub c/R/sub n/ product for the junctions with misorientation angle /spl alpha/=24/spl deg/ were close to 2/spl times/10/sup 4/ A/cm/sup 2/ and 190-260 /spl mu/V, respectively, while for /spl alpha/=37/spl deg/ it was found that j/sub c//spl ap/2/spl times/10/sup 3/ A/cm/sup 2/ and I/sub c/R/sub n//spl ap/90-120 /spl mu/V. The dc SQUIDs were made with typical inductances 20-80 pH, critical currents of 20-150 /spl mu/A and resulting voltage modulation 10-40 /spl mu/V. Noise measurements performed at 77 K revealed low 1/f noise with cut-off frequency about 10 Hz.

By modulating the rf voltage at near twice the synchrotron frequency, the longitudinal bunch shape can be modulated. This method can be used to shorten bunches. We show experimentally that the bunch shape can be modulated while preserving the longitudinal emittance when the rf voltage modulation is turned on adiabatically. Experimental measurements will be presented along with theoretical predictions.

The effect on effective area and voltage modulation depth of a serial superconducting quantum interference device (SQUID) magnetometer was simulated and observed. The variation in the effective area with the number N of serial SQUIDs was simulated. To reduce the beat phenomenon and optimize the serial SQUID magnetometer, the distance x between two adjacent SQUIDs should exceed 40 μm or even 65 μm, or dummy SQUIDs should be added at the edge of the serial SQUIDs. The optimal layout of a high-Tc serial SQUID array is discussed.

We have fabricated YBa2Cu3O7−δ edge junction dc SQUIDs working at 77 K with 5∼10 nm thick PrBa2Cu3O7−δ layer as the junction barrier. The SQUIDs were made by the pulsed laser film deposition technique and the photolithographic patterning with Ar+ milling. The junctions made showed resistively-shunted-junction (RSJ) characteristics near Tc and the SQUID voltage modulation in response to magnetic fields was on the order of μ V and was observed up to 80 K.

The developed address-vlotage-modulation drive generates pre-discharge in an ac-PDP (plasma display panel) by applying a rising address-pulse voltage during the sustain-pulse-open period. This pre-discharge increases the panel luminous efficiency by approximately 30%. This increase in luminous efficiency is a result of decreases in effective discharge voltage and electron temperature.

An active matrix EL VGA display is reported with full grayscale using temporal voltage modulation of the phosphor. The exceptional brightness and dynamic range of the ZnS:Mn EL phosphor permits a new gray scale scheme. Digital gamma correction and an extended range of levels achieve 128 to 256 monotonic shades.

An artificial step-edge junction for developing the high T c weak links is presented. The step-edge junction is fabricated by using the step edge of the double layer of the epitaxial YBaCuO films. The dc superconducting quantum interference device (SQUID) made of the junction shows a clear voltage-vs-flux (V-Φ) relation up to T=81.3 K. The voltage modulation depth ΔV of the V-Φ relation is ΔV=1.6 µV at T=77 K. A preliminary experiment shows that the magnetic-flux noise of the SQUID at T=77 K is, at most, Φ n =4.4×10-4Φ0/√Hz at f=10 Hz. These results show the promising properties of the step-edge junction for the weak link of high T c superconductors.

We have investigated the voltage tuning of b‐axis CdS phonon masers. Voltage modulation is found to be a fairly complex phenomenon involving amplitude as well as frequency modulation of the phonon maser output. Near threshold, the frequency modulation is typically of the order of 10 kHz/V. The response is flat up to frequencies of the order of the reciprocal of the acoustic transit time. At the higher driving voltages, the tuning is reduced. The device appears promising as a FM communications transmitter.

SRAM cell stability analysis is typically based on Static Noise Margin (SNM) evaluation when in hold mode, although memory errors may also occur during read operations. Given that SNM varies with each cell operation, a thorough analysis of SNM in read mode is required. In this paper we investigate the SNM of OAM cells during write operations. The Word-Line Voltage modulation is proposed as an alternative to improve cell stability when in this mode. We show that it is possible to improve 8T OAM cells stability during write operations while reducing current leakage, as opposed to present methods that improve cell stability at the cost of leakage increase.

By modulating the RF voltage at near twice the synchrotron frequency we are able to modulate the longitudinal bunch shape. We show experimentally that this can be done while preserving the longitudinal emittance when the RF voltage modulation is turned on adiabatically. Experimental measurements are presented along with theoretical predictions.

A low cost photometer is described which is intended to be used in conjunction with voltage modulation of the LEED suppressor grid.