Due to low investment cost and high reliability,a new scheme called DR-HVDC(Diode Rectifier based HVDC)transmission was recently proposed for grid integration of large offshore wind farms.However,in this scheme,the ap...Due to low investment cost and high reliability,a new scheme called DR-HVDC(Diode Rectifier based HVDC)transmission was recently proposed for grid integration of large offshore wind farms.However,in this scheme,the application of conventional control strategies for stability operation face several challenges due to the uncontrollability of the DR.In this paper,a coordinated control strategy of offshore wind farms using the DR-HVDC transmission technology to connect with the onshore grid,is investigated.A novel coordinated control strategy for DR-HVDC is proposed based on the analysis of the DC current control ability of the full-bridge-based modular multilevel converter(FB-MMC)at the onshore station and the input and output characteristics of the diode rectifier at the offshore.Considering the characteristics of operation stability and decoupling between reactive power and active power,a simplified design based on double-loop droop control for offshore AC voltage is proposed after power flow and voltage–current(I–V)characteristics of the offshore wind farm being analyzed.Furthermore,the impact of onshore AC fault to offshore wind farm is analyzed,and a fast fault detection and protection strategy without relying on communication is proposed.Case studies carried out by PSCAD/EMTDC verify the effectiveness of the proposed control strategy for the start up,power fluctuation,and onshore and offshore fault conditions.展开更多
The comprehensive understanding of the structure-dependent electrostatic discharge behaviors in a conventional diode-triggered silicon controlled rectifier （DTSCR） is presented in this paper. Combined with the devic...The comprehensive understanding of the structure-dependent electrostatic discharge behaviors in a conventional diode-triggered silicon controlled rectifier （DTSCR） is presented in this paper. Combined with the device simulation, a mathematical model is built to get a more in-depth insight into this phenomenon. The theoretical studies are verified by the transmission-line-pulsing （TLP） test results of the modified DTSCR structure, which is realized in a 65-nm complementary metal-oxide-semiconductor （CMOS） process. The detailed analysis of the physical mechanism is used to provide predictions as the DTSCR-based protection scheme is required. In addition, a method is also presented to achieve the tradeoff between the leakage and trigger voltage in DTSCR.展开更多
Rectifier diode production wastewater that contains acid,alkali and heavy metal ions in a company was treated by using neutralization/coagulation sedimentation method.Firstly,pH of wastewater was adjusted via neutrali...Rectifier diode production wastewater that contains acid,alkali and heavy metal ions in a company was treated by using neutralization/coagulation sedimentation method.Firstly,pH of wastewater was adjusted via neutralization reaction,and then heavy metal ions(Cu^(2+),Cr^(2+)and Pb^(2+))were removed by adding coagulant PAC and flocculant PAM.Different acid-alkali neutralization reactions were conducted under the process condition to analyze and compare their neutralization effects.The results showed that removal rates of heavy metal ions were high after coagulation test:Cu^(2+),Pb^(2+)and Cr^(2+)contents dropped from 13.230,0.032,and 1.720mg/L to 0.3,0.001,and 0.24mg/L;besides,total iron,total manganese and turbidity all had very good removal effects.展开更多
To suppress peak voltage on rectifier diodes in a full bridge( FB) converter,the mechanism of peak voltage was analyzed and an improved FB converter was proposed. One reason for peak voltage is the resonance of the tr...To suppress peak voltage on rectifier diodes in a full bridge( FB) converter,the mechanism of peak voltage was analyzed and an improved FB converter was proposed. One reason for peak voltage is the resonance of the transformer's leakage inductance and the rectifier diodes' junction capacitances. The other reason is that the fast reverse recovery current of the rectifier diodes flows through the transformer's leakage inductance. An H bridge composed of four diodes,an auxiliary inductance, and a clamping winding were adopted in the proposed converter,and peak voltage was suppressed by varying the equivalent inductance, principally in different operating modes. Experimental results demonstrate that the peak voltage of rectifier diodes decreases by 43%,the auxiliary circuit does not lead to additional loss, and the rising rate, resonant frequency,and amplitude of the rectifier diodes' voltage decrease.Peak voltage and electromagnetic interference( EMI) of rectifier diodes are suppressed.展开更多
The effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diodes were studied.We fabricated the PIN rectifier diodes with different initial oxygen concentrations,and analyzed the elec...The effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diodes were studied.We fabricated the PIN rectifier diodes with different initial oxygen concentrations,and analyzed the electrical properties,anisotropic preferred etching by means of optical microscopy,Fourier transform infrared spectroscopy and transmission electron microscopy.It is pointed out that the reverse leakage current increases exponentially with the increasing initial oxygen concentration.Furtherly,we researched and analyzed the mechanism of the effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diode.It is shown that the oxygen precipitations present in an "S" curve with increasing initial oxygen concentration after high temperature diffusion.The main reason is that the nucleation and growth of oxygen precipitation at high temperature induce bulk oxidation-induced defects (B-OSF),which are mainly dislocations,and a small amount of rod stacking faults.The density of B-OSF increases with the increasing initial oxygen concentration.The existence of B-OSF has great effects on the reverse leakage current of PIN rectifier diode.展开更多
In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)i...In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)is used to generate orthogonal signals with the same frequency to estimate the grid voltage.In addition,in view of the deviation between actual and reference power in the three-phase PWM rectifier traditional PDPC strategy,a power correction link is designed to correct the power reference value.The grid voltage sensor free algorithm based on TOGI and the corrected PDPC strategy are applied to three-phase PWM rectifier and simulated on the simulation platform.Simulation results show that the proposed method can effectively eliminate the power tracking deviation and the grid voltage.The effectiveness of the proposed method is verified by comparing the simulation results.展开更多
Lateralβ-Ga_(2)O_(3)Schottky barrier diodes(SBDs)each are fabricated on an unintentionally doped(-201)n-typeβ-Ga_(2)O_(3)single crystal substrate by designing L-shaped electrodes.By introducing sidewall electrodes o...Lateralβ-Ga_(2)O_(3)Schottky barrier diodes(SBDs)each are fabricated on an unintentionally doped(-201)n-typeβ-Ga_(2)O_(3)single crystal substrate by designing L-shaped electrodes.By introducing sidewall electrodes on both sides of the conductive channel,the SBD demonstrates a high current density of 223 mA/mm and low specific on-resistance of4.7 mΩ·cm^(2).Temperature-dependent performance is studied and the Schottky barrier height is extracted to be in a range between 1.3 eV and 1.35 eV at temperatures ranging from 20℃to 150℃.These results suggest that the lateralβ-Ga_(2)O_(3)SBD has a tremendous potential for future power electronic applications.展开更多
In order to reduce the latch-up risk of the traditional low-voltage-triggered silicon controlled rectifier(LVTSCR), a novel LVTSCR with embedded clamping diode(DC-LVTSCR) is proposed and verified in a 0.18-μm CMOS pr...In order to reduce the latch-up risk of the traditional low-voltage-triggered silicon controlled rectifier(LVTSCR), a novel LVTSCR with embedded clamping diode(DC-LVTSCR) is proposed and verified in a 0.18-μm CMOS process. By embedding a p+implant region into the drain of NMOS in the traditional LVTSCR, a reversed Zener diode is formed by the p+implant region and the n+bridge, which helps to improve the holding voltage and decrease the snapback region.The physical mechanisms of the LVTSCR and DC-LVTSCR are investigated in detail by transmission line pulse(TLP)tests and TCAD simulations. The TLP test results show that, compared with the traditional LVTSCR, the DC-LVTSCR exhibits a higher holding voltage of 6.2 V due to the embedded clamping diode. By further optimizing a key parameter of the DC-LVTSCR, the holding voltage can be effectively increased to 8.7 V. Therefore, the DC-LVTSCR is a promising ESD protection device for circuits with the operation voltage of 5.5–7 V.展开更多
To solve the input current harmonic pollution of the high power rectifier system,18-pulse rectifier based on a kind of active harmonic suppression technique at dc side is proposed in this paper.The pulse rectifier emp...To solve the input current harmonic pollution of the high power rectifier system,18-pulse rectifier based on a kind of active harmonic suppression technique at dc side is proposed in this paper.The pulse rectifier employs three-phase diode bridges,each of them followed by a boost converter.Unlike the conventional three-phase unity-power-factor diode rectifier,the ideal sinusoidal main currents of circuit topology are obtained by control its output current or input currents of three boost converters for approximately triangular modulation.The theoretical of modulation strategy and characteristics of input and output currents about the proposed rectifier are analyzed in detail.Simulation results by Matlab/Simulink demonstrate that the proposed rectifier draws nearly sinusoidal current and power quality index is improved.The correctness of the theoretical analysis is validated.展开更多
A rectifier circuit for wireless energy harvesting(WEH) with a wide input power range is proposed in this paper. We build up accurate models of the diodes to improve the accuracy of the design of the rectifier. Due to...A rectifier circuit for wireless energy harvesting(WEH) with a wide input power range is proposed in this paper. We build up accurate models of the diodes to improve the accuracy of the design of the rectifier. Due to the nonlinear characteristics of the diodes, a new band-stop structure is introduced to reduce the imaginary part impedance and suppress harmonics. A novel structure with double branches and an optimized λ/4 microstrip line is proposed to realize the power division ratio adjustment by the input power automatically. The proposed two branches can satisfy the two cases with input power of-20 dBm to 0 dBm and 0 dBm to 15 dBm, respectively. Here, dBm = 10 log(P mW), and P represents power. An impedance compression network(ICN) is correspondingly designed to maintain the input impedance stability over the wide input power range. A rectifier that works at 2.45 GHz is implemented. The measured results show that the highest efficiency can reach 51.5% at the output power of 0 dBm and higher than 40% at the input power of-5 dBm to 12 dBm.展开更多
This paper presents a PFCVF (Power Factor Correction) rectifier that uses a variable frequency source for alternators for electric and hybrid vehicles application. In such application, the frequency of the signal in t...This paper presents a PFCVF (Power Factor Correction) rectifier that uses a variable frequency source for alternators for electric and hybrid vehicles application. In such application, the frequency of the signal in the alternator changes according to the vehicle speed, more over the loading effect on the alternator introduces harmonic currents and increases the alternator apparent power requirements. To overcome these problems and aiming more stability and better design of the alternator, a new third harmonic injection technique is proposed. This technique allows to preserve a good THD (Total Harmonic Distortion) of the input source at any frequency and to decrease losses in semiconductors switches, thereby allowing more stability and reducing the apparent power requirements. A comparative study between the standard and the new technique is made and highlights the effectiveness of the new design. A detailed analysis of the proposed topology is presented and simulations as well as experimental results are shown.展开更多
Ni/β-Ga_2 O_3 lateral Schottky barrier diodes(SBDs) were fabricated on a Sn-doped quasi-degenerate n^+-Ga_2 O_3(201)bulk substrate. The resultant diodes with an area of 7.85 ×10^(-5) cm^2 exhibited excellent rec...Ni/β-Ga_2 O_3 lateral Schottky barrier diodes(SBDs) were fabricated on a Sn-doped quasi-degenerate n^+-Ga_2 O_3(201)bulk substrate. The resultant diodes with an area of 7.85 ×10^(-5) cm^2 exhibited excellent rectifying characteristics with an ideality factor of 1.21, a forward current density(J) of 127.4 A/cm2 at 1.4 V, a specific on-state resistance(R_(on,sp)) of1.54 mΩ·cm^2,and an ultra-high on/off ratio of 2.1 ×10^(11) at±1 V. Due to a small depletion region in the highly-doped substrate, a breakdown feature was observed at-23 V, which corresponded to a breakdown field of 2.1 MV/cm and a power figure-of-merit(VB2/R_(on)) of 3.4×10~5 W/cm^2. Forward current-voltage characteristics were described well by the thermionic emission theory while thermionic field emission and trap-assisted tunneling were the dominant transport mechanisms at low and high reverse biases, respectively, which was a result of the contribution of deep-level traps at the metal-semiconductor interface. The presence of interfacial traps also caused the difference in Schottky barrier heights of 1.31 eV and 1.64 eV respectively determined by current-voltage and capacitance-voltage characteristics. With reduced trapping effect and incorporation of drift layers, the β-Ga_2 O_3 SBDs could further provide promising materials for delivering both high current output and high breakdown voltage.展开更多
This paper presents a cascode configuration synchronous rectifier device based on silicon MOSFET and Schottky diode,which can replace traditional power diode directly.This structure has self-driven ability with simple...This paper presents a cascode configuration synchronous rectifier device based on silicon MOSFET and Schottky diode,which can replace traditional power diode directly.This structure has self-driven ability with simple external circuit,and the conduction characteristic is preferable to a power diode.Static characterization and switching behavior analysis of proposed structure are conducted in this paper.The switching process is illustrated in detail using real model which considers the parasitic inductances and the nonlinearity of junction capacitors.The real time internal voltage and current value during switching transition are deduced with the equivalent circuit.To validate the analysis,two voltage specification rectifiers are built.Finally,double-pulse test results and the practical design example verify the performance advantages of proposed structure.展开更多
Energy harvesting is a rapidly growing area in many scientific and engineering-related fields due to the demand for many applications. This paper focuses on the design and simulation of the voltage doubler rectifier c...Energy harvesting is a rapidly growing area in many scientific and engineering-related fields due to the demand for many applications. This paper focuses on the design and simulation of the voltage doubler rectifier circuit at 2.45 GHz operating frequency. The design of a rectifier is optimized based on the use of Schottky diode HSMS 286 B due to its low forward voltage at this frequency. 2 stages of the Schottky diode voltage doublers circuit are designed and simulated in this paper. The shunt capacitor and optimal load resistance are also introduced in the course to reduce signal loss. A multi-stage rectifier is used to produce maximum power conversion from AC to DC. The simulated results present that the maximum output voltage of 6.651 V with an input power of 25 dBm is produced, which presents a maximum power conversion efficiency of 73.13%, which applicable in small device applications.展开更多
The electronic transport properties of armchair-edged boron nitride nanoribbons（ABNNRs） devices were investigated by the first principle calculations. The calculated results show that the ABNNR device doped with car...The electronic transport properties of armchair-edged boron nitride nanoribbons（ABNNRs） devices were investigated by the first principle calculations. The calculated results show that the ABNNR device doped with carbon atoms in one of the electrodes acts as a high performance nanoribbon rectifier. It is interesting to find that there exists a particular bias-polarity-dependent matching band between two electrodes,leading to a similar current-voltage（I-V） behavior as conventional P-N diodes. The I-V behavior presents a linear positive-bias I-V characteristic,an absolutely negligible leakage current,and a stable rectifying property under a large bias region. The results suggest that C doping might be an effective way to raise ABNNRs devices＇ rectifying performance.展开更多
Grid forming controllers need to operate with a large variation of grid parameters and grid structures,for instance,during black-start operation,connection to HVDC diode rectifiers,etc.This paper proposes a methodolog...Grid forming controllers need to operate with a large variation of grid parameters and grid structures,for instance,during black-start operation,connection to HVDC diode rectifiers,etc.This paper proposes a methodology for the synthesis of robust grid forming controllers for HVDC diode rectifier based wind power plants using H_(∞)control.The different operating modes of an HVDC diode rectifier based wind power plant should be considered for the controller synthesis using the proposed H_(∞)controller design methodology.The proposed methodology for grid forming controller design improves the performance and robustness of well tuned standard proportional-resonant based controllers.The results have been validated experimentally at the wind turbine level by means of a small power prototype.The validation at the system level has been carried out using a realistic simulation of the HVDC diode rectifier-connected wind power plant.展开更多
In this paper,a grid voltage sensorless model predictive control is proposed and verified by simulation and experimental tests for a PWM rectifier.The presented method is simple and cost effective due to no need of mo...In this paper,a grid voltage sensorless model predictive control is proposed and verified by simulation and experimental tests for a PWM rectifier.The presented method is simple and cost effective due to no need of modulator and voltage sensors.The developed sliding mode voltage observer(SMVO)can theoretically track the grid voltage accurately without phase lag and magnitude error.Based on the proposed SMVO,the finite control set-model predictive control(FCS-MPC)is incorporated for power regulation.The active power and reactive power are calculated and predicted using the measured current and the estimated grid voltage from the SMVO.With the predicated power for one-step delay compensation,the best voltage vector minimizing the tracking error is selected by FCS-MPC.The whole algorithm is implemented in stationary frame without using Park's transformation.Both the simulation and experimental results validate the effectiveness of the proposed method.展开更多
基金supported by State Grid Science and Technology Project“Study on Key Technologies of Large Scale Offshore Wind Power Integrating with Onshore Grid”(4000-202055045A-0-0-00)
文摘Due to low investment cost and high reliability,a new scheme called DR-HVDC(Diode Rectifier based HVDC)transmission was recently proposed for grid integration of large offshore wind farms.However,in this scheme,the application of conventional control strategies for stability operation face several challenges due to the uncontrollability of the DR.In this paper,a coordinated control strategy of offshore wind farms using the DR-HVDC transmission technology to connect with the onshore grid,is investigated.A novel coordinated control strategy for DR-HVDC is proposed based on the analysis of the DC current control ability of the full-bridge-based modular multilevel converter(FB-MMC)at the onshore station and the input and output characteristics of the diode rectifier at the offshore.Considering the characteristics of operation stability and decoupling between reactive power and active power,a simplified design based on double-loop droop control for offshore AC voltage is proposed after power flow and voltage–current(I–V)characteristics of the offshore wind farm being analyzed.Furthermore,the impact of onshore AC fault to offshore wind farm is analyzed,and a fast fault detection and protection strategy without relying on communication is proposed.Case studies carried out by PSCAD/EMTDC verify the effectiveness of the proposed control strategy for the start up,power fluctuation,and onshore and offshore fault conditions.
基金Project supported by the Beijing Municipal Natural Science Foundation,China(Grant No.4162030)the National Science and Technology Major Project of China(Grant No.2013ZX02303002)
文摘The comprehensive understanding of the structure-dependent electrostatic discharge behaviors in a conventional diode-triggered silicon controlled rectifier （DTSCR） is presented in this paper. Combined with the device simulation, a mathematical model is built to get a more in-depth insight into this phenomenon. The theoretical studies are verified by the transmission-line-pulsing （TLP） test results of the modified DTSCR structure, which is realized in a 65-nm complementary metal-oxide-semiconductor （CMOS） process. The detailed analysis of the physical mechanism is used to provide predictions as the DTSCR-based protection scheme is required. In addition, a method is also presented to achieve the tradeoff between the leakage and trigger voltage in DTSCR.
文摘Rectifier diode production wastewater that contains acid,alkali and heavy metal ions in a company was treated by using neutralization/coagulation sedimentation method.Firstly,pH of wastewater was adjusted via neutralization reaction,and then heavy metal ions(Cu^(2+),Cr^(2+)and Pb^(2+))were removed by adding coagulant PAC and flocculant PAM.Different acid-alkali neutralization reactions were conducted under the process condition to analyze and compare their neutralization effects.The results showed that removal rates of heavy metal ions were high after coagulation test:Cu^(2+),Pb^(2+)and Cr^(2+)contents dropped from 13.230,0.032,and 1.720mg/L to 0.3,0.001,and 0.24mg/L;besides,total iron,total manganese and turbidity all had very good removal effects.
基金National Natural Science Foundation of China(No.41004027)Cooperation Innovation Projects of Ministry of Education,China(No.OSR-02-01)
文摘To suppress peak voltage on rectifier diodes in a full bridge( FB) converter,the mechanism of peak voltage was analyzed and an improved FB converter was proposed. One reason for peak voltage is the resonance of the transformer's leakage inductance and the rectifier diodes' junction capacitances. The other reason is that the fast reverse recovery current of the rectifier diodes flows through the transformer's leakage inductance. An H bridge composed of four diodes,an auxiliary inductance, and a clamping winding were adopted in the proposed converter,and peak voltage was suppressed by varying the equivalent inductance, principally in different operating modes. Experimental results demonstrate that the peak voltage of rectifier diodes decreases by 43%,the auxiliary circuit does not lead to additional loss, and the rising rate, resonant frequency,and amplitude of the rectifier diodes' voltage decrease.Peak voltage and electromagnetic interference( EMI) of rectifier diodes are suppressed.
基金Funded by the National Natural Science Foundation of China (No. 62004154)。
文摘The effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diodes were studied.We fabricated the PIN rectifier diodes with different initial oxygen concentrations,and analyzed the electrical properties,anisotropic preferred etching by means of optical microscopy,Fourier transform infrared spectroscopy and transmission electron microscopy.It is pointed out that the reverse leakage current increases exponentially with the increasing initial oxygen concentration.Furtherly,we researched and analyzed the mechanism of the effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diode.It is shown that the oxygen precipitations present in an "S" curve with increasing initial oxygen concentration after high temperature diffusion.The main reason is that the nucleation and growth of oxygen precipitation at high temperature induce bulk oxidation-induced defects (B-OSF),which are mainly dislocations,and a small amount of rod stacking faults.The density of B-OSF increases with the increasing initial oxygen concentration.The existence of B-OSF has great effects on the reverse leakage current of PIN rectifier diode.
基金National Natural Science Foundation of China(Nos.51767013,52067013)。
文摘In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)is used to generate orthogonal signals with the same frequency to estimate the grid voltage.In addition,in view of the deviation between actual and reference power in the three-phase PWM rectifier traditional PDPC strategy,a power correction link is designed to correct the power reference value.The grid voltage sensor free algorithm based on TOGI and the corrected PDPC strategy are applied to three-phase PWM rectifier and simulated on the simulation platform.Simulation results show that the proposed method can effectively eliminate the power tracking deviation and the grid voltage.The effectiveness of the proposed method is verified by comparing the simulation results.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018 YFB 2200500)the National Natural Science Foundation of China(Grant Nos.62050073,62090054,and 61975196)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDY-SSW-JSC022)。
文摘Lateralβ-Ga_(2)O_(3)Schottky barrier diodes(SBDs)each are fabricated on an unintentionally doped(-201)n-typeβ-Ga_(2)O_(3)single crystal substrate by designing L-shaped electrodes.By introducing sidewall electrodes on both sides of the conductive channel,the SBD demonstrates a high current density of 223 mA/mm and low specific on-resistance of4.7 mΩ·cm^(2).Temperature-dependent performance is studied and the Schottky barrier height is extracted to be in a range between 1.3 eV and 1.35 eV at temperatures ranging from 20℃to 150℃.These results suggest that the lateralβ-Ga_(2)O_(3)SBD has a tremendous potential for future power electronic applications.
基金National Natural Science Foundation of China(Grant No.61504049)the China Postdoctoral Science Foundation(Grant No.2016M600361).
文摘In order to reduce the latch-up risk of the traditional low-voltage-triggered silicon controlled rectifier(LVTSCR), a novel LVTSCR with embedded clamping diode(DC-LVTSCR) is proposed and verified in a 0.18-μm CMOS process. By embedding a p+implant region into the drain of NMOS in the traditional LVTSCR, a reversed Zener diode is formed by the p+implant region and the n+bridge, which helps to improve the holding voltage and decrease the snapback region.The physical mechanisms of the LVTSCR and DC-LVTSCR are investigated in detail by transmission line pulse(TLP)tests and TCAD simulations. The TLP test results show that, compared with the traditional LVTSCR, the DC-LVTSCR exhibits a higher holding voltage of 6.2 V due to the embedded clamping diode. By further optimizing a key parameter of the DC-LVTSCR, the holding voltage can be effectively increased to 8.7 V. Therefore, the DC-LVTSCR is a promising ESD protection device for circuits with the operation voltage of 5.5–7 V.
基金Natural Science Foundation of Gansu Province Education Department(No.2017A-020)National Natural Science Foundation of China(No.51767013)Science and Technology Research and Development Plan of China Railway Corporation(No.2017J012-A)
文摘To solve the input current harmonic pollution of the high power rectifier system,18-pulse rectifier based on a kind of active harmonic suppression technique at dc side is proposed in this paper.The pulse rectifier employs three-phase diode bridges,each of them followed by a boost converter.Unlike the conventional three-phase unity-power-factor diode rectifier,the ideal sinusoidal main currents of circuit topology are obtained by control its output current or input currents of three boost converters for approximately triangular modulation.The theoretical of modulation strategy and characteristics of input and output currents about the proposed rectifier are analyzed in detail.Simulation results by Matlab/Simulink demonstrate that the proposed rectifier draws nearly sinusoidal current and power quality index is improved.The correctness of the theoretical analysis is validated.
基金Key Laboratory of Chinese Academy of Sciences Foundation,China(No. 20190918)。
文摘A rectifier circuit for wireless energy harvesting(WEH) with a wide input power range is proposed in this paper. We build up accurate models of the diodes to improve the accuracy of the design of the rectifier. Due to the nonlinear characteristics of the diodes, a new band-stop structure is introduced to reduce the imaginary part impedance and suppress harmonics. A novel structure with double branches and an optimized λ/4 microstrip line is proposed to realize the power division ratio adjustment by the input power automatically. The proposed two branches can satisfy the two cases with input power of-20 dBm to 0 dBm and 0 dBm to 15 dBm, respectively. Here, dBm = 10 log(P mW), and P represents power. An impedance compression network(ICN) is correspondingly designed to maintain the input impedance stability over the wide input power range. A rectifier that works at 2.45 GHz is implemented. The measured results show that the highest efficiency can reach 51.5% at the output power of 0 dBm and higher than 40% at the input power of-5 dBm to 12 dBm.
文摘This paper presents a PFCVF (Power Factor Correction) rectifier that uses a variable frequency source for alternators for electric and hybrid vehicles application. In such application, the frequency of the signal in the alternator changes according to the vehicle speed, more over the loading effect on the alternator introduces harmonic currents and increases the alternator apparent power requirements. To overcome these problems and aiming more stability and better design of the alternator, a new third harmonic injection technique is proposed. This technique allows to preserve a good THD (Total Harmonic Distortion) of the input source at any frequency and to decrease losses in semiconductors switches, thereby allowing more stability and reducing the apparent power requirements. A comparative study between the standard and the new technique is made and highlights the effectiveness of the new design. A detailed analysis of the proposed topology is presented and simulations as well as experimental results are shown.
基金supported by the National Key R&D Program of China(Grant No.2017YFB0403003)the National Natural Science Foundation of China(Grant Nos.61774081,61322403,and 91850112)+3 种基金the State Key R&D Project of Jiangsu,China(Grant No.BE2018115)Shenzhen Fundamental Research Project,China(Grant Nos.201773239 and 201888588)State Key Laboratory of Wide-Bandgap Semiconductor Power Electric Devices,China(Grant No.2017KF001)the Fundamental Research Funds for the Central Universities,China(Grant Nos.021014380093 and 021014380085)
文摘Ni/β-Ga_2 O_3 lateral Schottky barrier diodes(SBDs) were fabricated on a Sn-doped quasi-degenerate n^+-Ga_2 O_3(201)bulk substrate. The resultant diodes with an area of 7.85 ×10^(-5) cm^2 exhibited excellent rectifying characteristics with an ideality factor of 1.21, a forward current density(J) of 127.4 A/cm2 at 1.4 V, a specific on-state resistance(R_(on,sp)) of1.54 mΩ·cm^2,and an ultra-high on/off ratio of 2.1 ×10^(11) at±1 V. Due to a small depletion region in the highly-doped substrate, a breakdown feature was observed at-23 V, which corresponded to a breakdown field of 2.1 MV/cm and a power figure-of-merit(VB2/R_(on)) of 3.4×10~5 W/cm^2. Forward current-voltage characteristics were described well by the thermionic emission theory while thermionic field emission and trap-assisted tunneling were the dominant transport mechanisms at low and high reverse biases, respectively, which was a result of the contribution of deep-level traps at the metal-semiconductor interface. The presence of interfacial traps also caused the difference in Schottky barrier heights of 1.31 eV and 1.64 eV respectively determined by current-voltage and capacitance-voltage characteristics. With reduced trapping effect and incorporation of drift layers, the β-Ga_2 O_3 SBDs could further provide promising materials for delivering both high current output and high breakdown voltage.
基金supported in part by the National Natural Science Foundation of China (No.51777093)
文摘This paper presents a cascode configuration synchronous rectifier device based on silicon MOSFET and Schottky diode,which can replace traditional power diode directly.This structure has self-driven ability with simple external circuit,and the conduction characteristic is preferable to a power diode.Static characterization and switching behavior analysis of proposed structure are conducted in this paper.The switching process is illustrated in detail using real model which considers the parasitic inductances and the nonlinearity of junction capacitors.The real time internal voltage and current value during switching transition are deduced with the equivalent circuit.To validate the analysis,two voltage specification rectifiers are built.Finally,double-pulse test results and the practical design example verify the performance advantages of proposed structure.
文摘Energy harvesting is a rapidly growing area in many scientific and engineering-related fields due to the demand for many applications. This paper focuses on the design and simulation of the voltage doubler rectifier circuit at 2.45 GHz operating frequency. The design of a rectifier is optimized based on the use of Schottky diode HSMS 286 B due to its low forward voltage at this frequency. 2 stages of the Schottky diode voltage doublers circuit are designed and simulated in this paper. The shunt capacitor and optimal load resistance are also introduced in the course to reduce signal loss. A multi-stage rectifier is used to produce maximum power conversion from AC to DC. The simulated results present that the maximum output voltage of 6.651 V with an input power of 25 dBm is produced, which presents a maximum power conversion efficiency of 73.13%, which applicable in small device applications.
基金supported by the National Natural Science Foundation of China(21401023 and 21374017)Cultivating Fund for Excellent Young Scholar of Fujian Normal University(FJSDJK2012063)Program for Innovative Research Team in Science and Technology in Fujian Province University(IRTSTFJ)
文摘The electronic transport properties of armchair-edged boron nitride nanoribbons（ABNNRs） devices were investigated by the first principle calculations. The calculated results show that the ABNNR device doped with carbon atoms in one of the electrodes acts as a high performance nanoribbon rectifier. It is interesting to find that there exists a particular bias-polarity-dependent matching band between two electrodes,leading to a similar current-voltage（I-V） behavior as conventional P-N diodes. The I-V behavior presents a linear positive-bias I-V characteristic,an absolutely negligible leakage current,and a stable rectifying property under a large bias region. The results suggest that C doping might be an effective way to raise ABNNRs devices＇ rectifying performance.
基金supported by the Spanish Research Agency through grant PID2020-112943RB-100 funded by MCIN/AEI/10.13039/501100011033grant PDC2021-121077-100 funded by MCIN/AEI/10.13039/501100011033by the European Union Next Generation EU/PRTR。
文摘Grid forming controllers need to operate with a large variation of grid parameters and grid structures,for instance,during black-start operation,connection to HVDC diode rectifiers,etc.This paper proposes a methodology for the synthesis of robust grid forming controllers for HVDC diode rectifier based wind power plants using H_(∞)control.The different operating modes of an HVDC diode rectifier based wind power plant should be considered for the controller synthesis using the proposed H_(∞)controller design methodology.The proposed methodology for grid forming controller design improves the performance and robustness of well tuned standard proportional-resonant based controllers.The results have been validated experimentally at the wind turbine level by means of a small power prototype.The validation at the system level has been carried out using a realistic simulation of the HVDC diode rectifier-connected wind power plant.
文摘In this paper,a grid voltage sensorless model predictive control is proposed and verified by simulation and experimental tests for a PWM rectifier.The presented method is simple and cost effective due to no need of modulator and voltage sensors.The developed sliding mode voltage observer(SMVO)can theoretically track the grid voltage accurately without phase lag and magnitude error.Based on the proposed SMVO,the finite control set-model predictive control(FCS-MPC)is incorporated for power regulation.The active power and reactive power are calculated and predicted using the measured current and the estimated grid voltage from the SMVO.With the predicated power for one-step delay compensation,the best voltage vector minimizing the tracking error is selected by FCS-MPC.The whole algorithm is implemented in stationary frame without using Park's transformation.Both the simulation and experimental results validate the effectiveness of the proposed method.
