A Novel Multiple DBC-staked units Package to Parallel More Chips for SiC Power Module

Silicon carbide(SiC) power modules play an essential role in the electric vehicle drive system. To improve their performance, reduce their size, and increase production efficiency, this paper proposes a multiple staked direct bonded copper(DBC) unit based power module packaging method to parallel more chips. This method utilizes mutual inductance cancellation effect to reduce parasitic inductance. Because the conduction area in the new package is doubled, the overall area of power module can be reduced. Entire power module is divided into smaller units to enhance manufacture yield, and improve design freedom. This paper provides a detailed design, analysis and fabrication procedure for the proposed package structure. Additionally, this paper offers several feasible solutions for the connection between power terminals and DBC untis. With the structure, 18dies were paralleled for each phase-leg in a econodual size power module. Both simulation and double pulse test results demonstrate that, compared to conventional layouts, the proposed package method has 74.8% smaller parasitic inductance and 34.9% lower footprint.

Research on Phase-Shifted Full-Bridge Circuit Based on Frequency and Phase-Shift Synthesis Modulation Strategy

The full-bridge converters usually use transformer leakage inductance and parallel resonant capacitors to achieve smooth current commutation and soft switching functions,which can easily cause problems such as energy leakage and significant duty cycle loss.This paper designs a novel full-bridge zero-current(FB-ZCS)converter with series resonant capacitors and proposes a frequency and phase-shift synthesis modulation(FPSSM)control strategy based on this topology.Compared with the traditional parallel resonant capacitor circuit,the passive components used are significantly reduced,the structure is simple,and there is only a slight energy loss.By controlling the charging time of the capacitor,it can be achieved without additional switches or auxiliary circuits.The automatic control of capacitor energy based on input current addresses the low efficiency of the traditional control strategies.This paper introduces its principle in detail and verifies it through simulation.Finally,an experimental prototype was built further to demonstrate the feasibility of the theory through experiments.The module can be applied to a photovoltaic DC collection system using input parallel output series(IPOS)cascade to provide a new topology for large-scale,long-distance DC transmission.

Tri-state Modulation Power Driving of Electro-hydraulic Proportional Amplifier

Switch electro-hydraulic proportional amplifier（PA） widely employs single switch modulation power driving（SSMPD） or reverse discharging power driving（RDPD） at present. SSMPD has slow dynamic response, and can＇t adjust independently the dither signal＇s amplitude and frequency; RDPD accelerates the current decay; consequently, it increases current ripple and power loss. For the purpose of solving the above mentioned problem, the tri-state modulation power driving（TSMPD） scheme was proposed for improving the performance of power driving. Detailedly, the hardware circuit for the tri-state modulation power driving is designed; the tri-state modulation algorithm is realized by digital signal processor（DSP）. The tri-state modulation power driving is investigated by experiments, comparetive experiments among the single switch modulation power driving（SSMPD）, reverse discharging power driving（RDPD）, and the TSMPD are implemented, and the experimental results demonstrate that the linearity error of TSMDP meets the requirement of PA; the current response of TSMSP is the best; the amplitude of ripple current of the TSMPD can be reduced without increasing frequency of PWM, in addition, dither signal amplitude and frequency can be adjusted independently for each other. It is very meaningful to guide the development of high performance proportional amplifier for high frequency response proportional solenoid.

Development of 8 MW Power Supply Based on Pulse Step Modulation Technique for Auxiliary Heating System on HL-2A

The high voltage power supply （HVPS） based on pulse step modulation （PSM） has already been developed for the auxiliary heating system on HL-2A. This power supply consists of many switch power supplies, and its output voltage can be obtained by modulating their delay time and pulse widths. The PSM topology and control principle are presented in this paper. The simple algorithms for the control system are explained clearly. The switch power supply （SPS） module has been built and the test results show it can meet the requirements of the auxiliary heating system. Now, 112 SPS modules and the whole system have already been developed. Its maximum output is about 72 kV/93 A. The protection time is less than 5 t＊s. The different outputs of this power supply are used for the electron cyclotron resonant heating （ECRH） system with different duty ratios. The experimental results of the entire system are presented. The results indicate that the whole system can meet the requirements of the auxiliary heating system on HL-2A.

Recent Developments of Modulation and Control for High-Power Current-Source-Converters Fed Electric Machine Systems

The pulse-width-modulated(PWM)current-source converters(CSCs)fed electric machine systems can be considered as a type of high reliability energy conversion systems,since they work with the long-life DC-link inductor and offer high fault-tolerant capability for short-circuit faults.Besides,they provide motor friendly waveforms and four-quadrant operation ability.Therefore,they are suitable for high-power applications of fans,pumps,compressors and wind power generation.The purpose of this paper is to comprehensively review recent developments of key technologies on modulation and control of high-power(HP)PWM-CSC fed electric machines systems,including reduction of low-order current harmonics,suppression of inductor–capacitor(LC)resonance,mitigation of common-mode voltage(CMV)and control of modular PWM-CSC fed systems.In particular,recent work on the overlapping effects during commutation,LC resonance suppression under fault-tolerant operation and collaboration of modular PMW-CSCs are described.Both theoretical analysis and some results in simulations and experiments are presented.Finally,a brief discussion regarding the future trend of the HP CSC fed electric machines systems is presented.

Broadband Dual-Input Doherty Power Amplifier Design Based on a Simple Adaptive Power Dividing Ratio Function

In this paper,a simple adaptive power dividing function for the design of a dual-input Doherty power amplifier(DPA)is presented.In the presented approaches,the signal separation function(SSF)at different frequency points can be characterized by a polynomial.And in the practical test,the coefficients of SSF can be determined by measuring a small number of data points of input power.Same as other dualinput DPAs,the proposed approach can also achieve high output power and back-off efficiency in a broadband operation band by adjusting the power distribution ratio flexibly.Finally,a 1.5-2.5 GHz highefficiency dual-input Doherty power amplifier is implemented according to this approach.The test results show that the peak power is 48.6-49.7d Bm,and the 6-d B back-off efficiency is 51.0-67.0%,and the saturation efficiency is 52.4-74.6%.The digital predistortion correction is carried out at the frequency points of 1.8/2.1GHz,and the adjacent channel power ratio is lower than-54.5d Bc.Simulation and experiment results can verify the effectiveness and correctness of the proposed method.

Adaptive Power Saving Receiver for DVB-H Exploiting Adaptive Modulation and Coding

Broadcasting live digital TV to a small battery-powered handheld device is very challenging. One of the most promising technologies to provide such services is DVB-H (Digital Video Broadcasting over Handheld). Power consumption has always been one of the most crucial challenges for handheld devices. In this paper, a novel Adaptive Modulation and Coding (AMC) framework is proposed for DVB-H systems to address the challenging problem of power consumption. The proposed power saving AMC framework operates by rearranging the transmitted frames in a pre-defined pattern. The adaptive receiver selects the appropriate modulation technique and/or code rate, one that achieves a target Bit Error Rate (BER), and then could be switched off and/or powered down resulting in significant potential for saving of reception and processing powers. Simulation of the DVB-H system under the proposed framework proved that the proposed power saving AMC framework is capable of achieving power saving up to 71.875% in COST207 Typical Urban 6-paths (TU6) channel. Furthermore, numerical analysis for the power saving potential and BER performance of the proposed framework is performed for both flat Rayleigh channel and multipath TU6 channel.

Joint Adaptive Modulation and Power Allocation in Cognitive Radio Networks

Link adaptation is an important issue in the design of cognitive radio networks, which aims at making efficient use of system resources. In this paper, we propose and investigate a joint adaptive modulation and power allocation algorithm in cognitive radio networks. Specifically, the modulation scheme and transmit power are adjusted adaptively according to channel conditions, interference limit and target signal-to-interference-plus-noise ratio (SINR). As such the total power consumption of cognitive users (CUs) is minimized while keeping both the target SINR of CUs and interference to primary user (PU) at an acceptable level. Simulation results are provided to show that the proposed algorithm achieves a significant gain in power saving.

Improving thermal efficiency and stability of laser welding process for magnesium alloy by combining power modulation and subatmospheric pressure environment

The laser welding(LW)process of highly reflective materials presents low thermal efficiency and poor stability.To solve the problem,the effects of subatmospheric environment on LW process,technological parameters in subatmospheric environment on weld formation and welding with sinusoidal modulation of laser power on the stability of LW process in subatmospheric environment were explored.The AZ31magnesium(Mg)alloy was used as the test materials.The test result revealed that the weld penetration in subatmospheric environment can increase by more than ten times compared with that under normal pressure.After the keyhole depth greatly rises,significantly periodic local bulge is observed on the backwall surface of the keyhole and the position of the bulge shifts along the direction of the keyhole depth.Eventually,the hump-shaped surface morphology of the welded seam is formed;moreover,the weld width in local zones in the lower part of the welded seam remarkably grows.During LW in subatmospheric environment,the weld penetration can be further greatly increased through power modulation.Besides,power modulation can inhibit the occurrence of bulges in local zones on the backwall of the keyhole during LW in subatmospheric environment,thus further curbing the significant growth of the weld widths of hump-shaped welding beads and local zones in the lower part of welded seams.Finally,the mechanism of synchronously improving the thermal efficiency and stability of LW process of highly reflective materials through power modulation in subatmospheric environment was illustrated.This was conducted according to theoretical analysis of recoil pressure and observation results of dynamic behaviors of laser induced plasma clouds and keyholes in the molten pool through high speed photography.

Digital Pulse Width Modulation Control in Power Electronic Circuits Design

The paper mainly focuses on the digital pulse width modulation (DPWM) control techniques for high performance power electronic circuit design. The problem to be solved in this study addresses the DPWM converter design for DC to DC conversion process. The control techniques have been utilized the Fuzzy Logic Rules Base method for proposed SIMULINK model of high performance power electronic circuit. The analytical calculations for real circuit design have been completed based on the mathematical modeling of the system. The results from the developed SIMULINK model confirm the target specifications of the high performance condition for power electronic circuit which was met the objective of this study. The numerical results have been carried out with the help of MATLAB/SIMULINK.

Effect of Hot Carrier on Amplitude Modulation and Demodulation of Gaussian High Power Helicon Wave in Homogeneous Longitudinally Magnetized Strain Dependent Dielectric Material

In the present communication, the hydrodynamic model is used to investigate the amplitude modulation as well as demodulation of an electromagnetic wave of high power helicon pump wave into another helicon wave in strain dependent dielectric material incorporating carrier heating (CH) effects. The consideration of CH in modulation and demodulation is prime importance for the adding of new dimension in analysis of amplification of acoustic helicon wave. By using the dispersion relation, threshold pump electric filed and growth rate of unstable mode from the modulation and demodulation of the high power helicon wave well above from the threshold value will be discussed in the present analysis. The numerical analysis is applied to a strain dependent dielectric material, BaTiO3 at room temperature and irradiated with high power helicon wave of frequency 1.78 × 1014 Hz. This material is very sensitive to the pump intensities, therefore during studies, Gaussian shape of the helicon pump wave is considered during the propagation in stain dependent dielectric material and opto-acoustic wave in the form of Gaussian profile (ω0,κ0) is induced longitudinally along the crystallographic plane of BaTiO3. Its variation is caused by the available magnetic field (ωc), interaction length (z) and pulsed duration of interaction (τ). From the analysis of numerical results, the incorporation of CH effect can effectively modify the magnitude of modulation or demodulation of the amplitude of high power helicon laser wave through diffusion process. Not only the amplitude modulation and demodulation of the wave, the diffusion of the CH effectively modifies the growth rate of unstable mode of frequency in BaTiO3. The propagation of the threshold electric field shows the sinusoidal or complete Gaussian profile, whereas this profile is found to be completely lost in growth of unstable mode. It has also been seen that the growth rate is observed to be of the order of 108 - 1010 s-1 but from diffusion of carrier heating, and that its order is enhanced from 1010 - 1012 s-1 with the variation of the magnetized frequency from 1 to 2.5 × 1014 Hz.

Simultaneous wireless information and power transfer with fixed and adaptive modulation

Activating Wireless Power Transfer (WPT) in Radio-Frequency (RF) to provide on-demand energy supply to widely deployed Internet of Everything devices is a key to the next-generation energy self-sustainable 6G network. However, Simultaneous Wireless Information and Power Transfer (SWIPT) in the same RF bands is challenging. The majority of previous studies compared SWIPT performance to Gaussian signaling with an infinite alphabet, which is impossible to implement in any realistic communication system. In contrast, we study the SWIPT system in a well-known Nakagami-m wireless fading channel using practical modulation techniques with finite alphabet. The attainable rate-energy-reliability tradeoff and the corresponding rationale are revealed for fixed modulation schemes. Furthermore, an adaptive modulation-based transceiver is provided for further expanding the attainable rate-energy-reliability region based on various SWIPT performances of different modulation schemes. The modulation switching thresholds and transmit power allocation at the SWIPT transmitter and the power splitting ratios at the SWIPT receiver are jointly optimized to maximize the attainable spectrum efficiency of wireless information transfer while satisfying the WPT requirement and the instantaneous and average BER constraints. Numerical results demonstrate the SWIPT performance of various fixed modulation schemes in different fading conditions. The advantage of the adaptive modulation-based SWIPT transceiver is validated.

Improved VSVPWM Modulation Method for Three-level NPC Inverter in Rural Power Grid

With the acceleration of agricultural electrification,a lot of nonlinear and shock loads appear in the rural power grid,and the resulting harmonic and reactive currents pollute the rural power grid more and more seriously.To solve the above problem,three-level neutral point clamped(NPC)inverters have been widely used,but their development is greatly restricted by the defect of neutral point voltage imbalance.In this paper,an improved virtual space vector pulse width modulation(VSVPWM)was proposed.Firstly,the mathematical models of various space vectors were established,and the influence of various space vectors on neutral point voltage was analyzed.The sum of the vector current at the neutral point was zero and the voltage control at the neutral point was completed by.introducing the time offset into different switching times of the redundant small vector.This method was simple in design and avoided the redundant calculation of the traditional VSVPWM method and tedious switch sequence design.This balancing control strategy could greatly reduce the influence of virtual vectors on neutral point voltage and effectively control the low-frequency oscillation of neutral point voltage.The validity of the method was verified by establishing a matlab simulation model.

MULTICARRIER DS-CDMA WITH ADAPTIVE MODULATION AND POWER ALLOCATION

Adaptive modulation and power allocation is introduced into the multicarrier DS-CDMA system to improve the system performance and bandwidth efficiency. First, the systemdesign appropriate for adaptive modulation and power allocation is given, then the algorithmof adaptive modulation and power allocation is applied. Simulation results demonstrate greatperformance improvement compared with the fixed modulated one.

ADAPTIVE MODULATION AND POWER CONTROL FOR THROUGHPUT ENHANCEMENT IN COGNITIVE RADIOS

To regulate the transmit-power and enhance the total throughput, a novel Transmit Power Control Game (TPCG) algorithm and an adaptive Modulation TPCG (M-TPCG) algorithm which combine bandwidth allocation, adaptive modulation and transmit-power control based on Space Time Block Coding (STBC) OFDM-CDMA system are designed and a cross-layer framework of database sharing is proposed. Simulation results show that the TPCG algorithm can regulate their transmitter powers and enhance the total throughput effectively, M-TPCG algorithm can achieve maximal system throughput. The performance of the cognitive radio system is improved obviously.

A Novel Pulse Density Modulation with Semi-bridgeless Active Rectifier in Inductive Power Transfer System for Rail Vehicle

In this paper,a novel pulse density modulation(PDM)with semi-bridgeless active rectifier(S-BAR)in inductive power transfer(IPT)system for rail vehicle is proposed.It is to reduce switching losses of the active rectifier in pickups.In the control method,the insulated-gate bipolar transistors(IGBTs)in the S-BAR are controlled by synchronous PDM signals,so that zero-voltage switching(ZVS)and zero-current switching(ZCS)can be achieved in the whole output power range.The output power is regulated by changing the pulse density(PD)of the S-BAR since the it is almost linear proportional with the PD in high quality factor of pickup side.The communication device between the primary side and pickup side is not necessary anymore.The detailed theoretical analyses of the PDM method are provided,and its advantages are shown in a 7.5kW IPT prototype for rail vehicle.The experimental results are presented to verify the analysis and demonstrate the performance.The overall efficiency of the system by PDM control is 74.2%which is improved by 4%compared with phase shift(PS)control at light load.

Modulated-Power Implantable Neuromodulation Devices and Their Impact on Surrounding Tissue Temperatures

This project was intended to determine whether the preprogrammed time-varying recharge protocol for a battery incased in a neuromodulation implant can give rise to tissue temperatures that surpass a safe level or are otherwise benign. The study included the development of a highly accurate model of all the thermal processes that are activated by the recharging of the battery contained within the neuromodulation implant. The model was implemented by numerical simulations performed for several realistic operating conditions. The computed spatial and temporal tissue temperature distributions were employed to estimate possible tissue damage by making use of two independent methodologies. Independent calorimeter-based experiments were performed to provide validation for the calculated rates of heat generation in the coils of the implant. Spatial and temporal tissue temperature distributions extracted from the numerical simulations revealed the thermal effects associated with several realistic operating protocols. None of the operating protocols gave rise to temperatures above 42℃. Numerical values of thermal tissue damage metrics were determined and compared with accepted values which correspond to the absence and the presence of tissue damage. The experimentally determined rate of heat generation in the implant coils validated that from electrical measurements to within 2%. Both the tissue temperature results and the thermal damage metrics found no evidence of tissue injury when time-varying preprogrammed protocols are used in the recharging of neuromodulation implant-encased batteries.

Analysis for Effects of Temperature Rise of PV Modules upon Driving Distance of Vehicle Integrated Photovoltaic Electric Vehicles

The development of vehicle integrated photovoltaics-powered electric vehicles (VIPV-EV) significantly reduces CO2 emissions from the transport sector to realize a decarbonized society. Although long-distance driving of VIPV-EV without electricity charging is expected in sunny regions, driving distance of VIPV-EV is affected by climate conditions such as solar irradiation and temperature rise of PV modules. In this paper, detailed analytical results for effects of climate conditions such as solar irradiation and temperature rise of PV modules upon driving distance of the VIPV-EV were presented by using test data for Toyota Prius and Nissan Van demonstration cars installed with high-efficiency InGaP/GaAs/InGaAs 3-junction solar cell modules with a module efficiency of more than 30%. The temperature rise of some PV modules studied in this study was shown to be expressed by some coefficients related to solar irradiation, wind speed and radiative cooling. The potential of VIPV-EV to be deployed in 10 major cities was also analyzed. Although sunshine cities such as Phoenix show the high reduction ratio of driving range with 17% due to temperature rise of VIPV modules, populous cities such as Tokyo show low reduction ratio of 9%. It was also shown in this paper that the difference between the driving distance of VIPV-EV driving in the morning and the afternoon is due to PV modules’ radiative cooling. In addition, the importance of heat dissipation of PV modules and the development of high-efficiency PV modules with better temperature coefficients was suggested in order to expand driving range of VIPV-EV. The effects of air-conditioner usage and partial shading in addition to the effects of temperature rise of VIPV modules were suggested as the other power losses of VIPV-EV.

Modulation Equations for Roll Waves on Vertically Falling Films of a Power-Law Fluid

Waves of finite amplitude on a thin layer of non-Newtonian fluid modelled as a power-law fluid are considered. In the long wave approximation, the system of equations taking into account the viscous and nonlinear effects has the hyper- bolic type. For the two-parameter family of periodic waves in the film flow on a vertical wall the modulation equations for nonlinear wave trains are derived and investigated. The stability criterium for roll waves based on the hyperbolicity of the modulation equations is suggested. It is shown that the evolution of stable roll waves can be described by self-similar solutions of the modulation equations.

POWER ALLOCATION AND ADAPTIVE MODULATION STRATEGY FOR MIMO-OFDM SYSTEMS WITH IMPERFECT CSI

The presented scheme named M-CAP (Maximum CAPacity) uses the CSI (Channel State Information) and its statistics to deduce an equivalent channel according to which the transmit power is allocated to the subchannels. And then modulation scheme is determined adaptively according to the power allocated to each subchannel. The advantage of the M-CAP scheme is that it combines power allocation and adaptive modulation while maintaining a large capacity. We demonstrate by computer simulations that the proposed M-CAP scheme can significantly improve system performance compared with the traditional schemes.