To enhance energy interaction among low-voltage stations(LVSs)and reduce the line loss of the distribution network,a novel operation mode of the micro-pumped storage system(mPSS)has been proposed based on the common r...To enhance energy interaction among low-voltage stations(LVSs)and reduce the line loss of the distribution network,a novel operation mode of the micro-pumped storage system(mPSS)has been proposed based on the common reservoir.First,some operation modes of mPSS are analyzed,which include the separated reservoir mode(SRM)and common reservoir mode(CRM).Then,based on the SRM,and CRM,an energy mutual assistance control model between LVSs has been built to optimize energy loss.Finally,in the simulation,compared to the model without pumped storage in the LVS,the SRMand CLRMcan decrease the total energy loss by 294.377 and 432.578 kWh,respectively.The configuration of mPSS can improve the utilization rate of the new energy source generation system,and relieve the pressure of transformer capacity in the LVS.Compared with the SRM,the proposed CRM has reduced the total energy loss by 138.201 kWh,increased the new energy consumption by 161.642 kWh,and decreased the line loss by 7.271 kWh.With the efficiency of the mPSS improving,the total energy loss reduction of CRM will be 3.5 times that of SRM.Further,the CRMcan significantly reduce the reservoir capacity construction of mPSS and ismore suitable for scenarios where the capacity configuration of mPSS is limited.展开更多
A novel CMOS bandgap reference is presented. The output reference of this new current mode structure can be set to an arbitrary value above the bandgap voltage of silicon,avoiding offset in application. It also overco...A novel CMOS bandgap reference is presented. The output reference of this new current mode structure can be set to an arbitrary value above the bandgap voltage of silicon,avoiding offset in application. It also overcomes the systematic mismatch of conventional current mode bandgap references. The proposed bandgap reference has been implemented in UMC 0.18μm mixed mode technology. Under the supply voltage of 1.6V, the proposed bandgap reference provides an output reference of 1.45V and consumes 27μA of supply current. Using no curvature compensation,it can reach a temperature coefficient of 23ppm/℃ from 30 to 150℃ with a line regulation of 2. 1mV/V from 1.6 to 3V and a PSRR of 40dB at DC frequency. The chip area of the bandgap reference （without pad） is 0. 088mm^2.展开更多
A single power supply common-gate （CG） current mode transimpedance preamplifier （TIA） is developed with a 0.5μm GaAs PHEMT process. The amplifier has a measured - 3dB bandwidth of 7. 5GHz and a transimpedance gai...A single power supply common-gate （CG） current mode transimpedance preamplifier （TIA） is developed with a 0.5μm GaAs PHEMT process. The amplifier has a measured - 3dB bandwidth of 7. 5GHz and a transimpedance gain of 45dBΩ. Both the input and output voltage standing wave ratios （VSWR） are less than 2 within the bandwidth. The equivalent input noise current spectral density varies from 14.3 to 22pA/√Hz, with an average value of 17. 2pA/√Hz. Having a timing jitter of 14ps and eye amplitude of about 138mV,the measured output eye diagram for 10Gb/s NRZ pseudorandom binary sequence （PRBS） is clear and satisfactory.展开更多
A practical method of current mode circuit symbolic analysis using Mathematica is proposed. With the powerful symbolic manipulation capacity of Mathematica, current mode circuit symbolic analysis can be significantly ...A practical method of current mode circuit symbolic analysis using Mathematica is proposed. With the powerful symbolic manipulation capacity of Mathematica, current mode circuit symbolic analysis can be significantly simplified. The active devices are modelled by nullors. The examples of current mode filters using CCIIs are presented.展开更多
An improved high-resolution current-mode sorter is presented.Its structure complexity is O(N),which is crucial to the expansion of its size,and its dynamic range is large.Only one clock signal and one reset signal are...An improved high-resolution current-mode sorter is presented.Its structure complexity is O(N),which is crucial to the expansion of its size,and its dynamic range is large.Only one clock signal and one reset signal are needed.No biasing signal is required.The operation point is constructed according to the input current,so it is self-adaptive,which is very important for an all-purpose component.In average value circuit,subtraction circuit,Winner-Take-All(WTA) circuit and control circuit,it has good performance even at a large input current.This sorter has high precision,high resolution and low power,as has been proved via HSPICE simulation.It can be implemented in the standard digital CMOS technology and widely used in many fields,so it is of great value in applications.展开更多
A feedback control system is needed to restrain plasma vertical displacement in EAST （Experimental Advanced Superconducting Toknmak）. A fast control power supply excites active feedback coils, which produces a magne...A feedback control system is needed to restrain plasma vertical displacement in EAST （Experimental Advanced Superconducting Toknmak）. A fast control power supply excites active feedback coils, which produces a magnetic field to control the plasma＇s displacement. With the development of EAST, new demands on the new fast control power supply have led to an enhanced ability of fast response and output current, as well as a new control mode. The structure of cascaded and paralleled H-bridges can meet the demand of extended capacity, and digital control can reMize current and voltage mixed control mode. The validity of the proposed scheme is confirmed by experiments.展开更多
Carbon Nano-Tube Field Effect Transistors(CNTFETs) are being widely studied as possible successors to silicon MOSFETs.Using current mode has many advantages such as performing sum operation by means of a simple wired ...Carbon Nano-Tube Field Effect Transistors(CNTFETs) are being widely studied as possible successors to silicon MOSFETs.Using current mode has many advantages such as performing sum operation by means of a simple wired connection.Also,direction of the current can be used to exhibit the sign of digits.It is expected that the advantages of current mode approaches will become even more important with increased speed requirements and decreased supply voltage.In this paper,we present five new circuit designs for differential absolute value in current mode logic which have been simulated by CNTFET model.The considered base current for this model is 2 μA and supply voltage is 0.9 V.In all of our designs we used N-type CNTFET current mirrors which operate as truncated difference circuits.The operation of Differential Absolute Value circuit calculates the difference between two input currents and our circuit designs are operate in 8 logic levels.展开更多
Influence of eddy current on transient characteristics of common rail injector solenoid valve was studied in this paper. Experimental investigations of drive current and power source volt- age of both drive current as...Influence of eddy current on transient characteristics of common rail injector solenoid valve was studied in this paper. Experimental investigations of drive current and power source volt- age of both drive current ascending and descending process were conducted on a common rail injec- tor solenoid valve. A new discretizing calculation method of solenoid valve flux linkage was put for- ward for the first time based on the experimental results and drive circuit principle, and flux linkage of both drive current ascending and descending process were evaluated. New inductance calculation methods for drive current ascending and descending process respectively were also presented. Influ- ence of parasitic inductance was evaluated. Results indicate that the air gap, under which the transi- ent flux linkage of the solenoid valve is the biggest, varies with drive current due to eddy current. Flux linkage of drive current descending process is bigger than that of drive current ascending process under the same drive current and the same air gap width. Eddy current can reduce the delay between the time that drive current begins to descend and the time that armature begins to move downward. Inductance of drive current descending process is bigger than that of drive current as- cending process over larger scope of drive current, but the difference becomes smaller with the in- creasing of air gap width. The differences of both flux linkage and inductance between drive current ascending and descending process are caused by the eddy current in core and armature materials.展开更多
A multi-hole vertical-cavity surface-emitting laser （VCSEL） operating in stable single mode with a low threshold current was produced by introducing multi-leaf scallop holes on the top distributed Bragg-refleetor of...A multi-hole vertical-cavity surface-emitting laser （VCSEL） operating in stable single mode with a low threshold current was produced by introducing multi-leaf scallop holes on the top distributed Bragg-refleetor of an oxidation- confined 850 nm VCSEL. The single-mode output power of 2.6 mW, threshold current of 0.6 mA, full width of half maximum lasing spectrum of less than 0.1 nm, side mode suppression ratio of 28.4 dB, and far-field divergence angle of about 10% are obtained. The effects of different hole depths on the optical characteristics are simulated and analysed, including far-field divergence, spectrum and lateral cavity mode. The single-mode performance of this multi-hole device is attributed to the large radiation loss from the inter hole spacing and the scattering loss at the bottom of the holes, particularly for higher order modes.展开更多
Based on a linearized MHD model, the effect of equilibrium current profiles on external kink modes in tokamaks is studied by MARS code. Three types of equilibrium current profiles are adopted in this work. Firstly, a ...Based on a linearized MHD model, the effect of equilibrium current profiles on external kink modes in tokamaks is studied by MARS code. Three types of equilibrium current profiles are adopted in this work. Firstly, a set of parabolic equilibrium current profiles are chosen. In these profiles the maximum current values in the center of the plasma are fixed, and the currents have different gradient and jump at the plasma boundary. The effects of the current gradient and jump on the growth rate of external kink mode are investigated. It is found that the current jump which causes the q profiles to change plays an important role in the externM kink modes in tokamaks. Secondly, a set of step equilibrium current profiles with different jump positions are chosen. The effect of jump position on external kink modes is discussed. Thirdly, a set of parabolic equilibrium current profiles with current bumps are chosen for the case of off-axis heating. The effects of height~ width and position of the current bumps on external kink modes are analyzed. The fiat equilibrium current profiles are disadvantageous for the MHD stabilities of tokamaks, because of the large current jump at the plasma edge. The peaked equilibrium current profiles and a large and localized current bump near the plasma edge benefit the MHD stabilities of tokamaks.展开更多
This paper presents a new current-mode single input multi output (SIMO) type biquad employing one voltage differencing transconductance amplifier (VDTA), two grounded capacitors and a single grounded resistor. The con...This paper presents a new current-mode single input multi output (SIMO) type biquad employing one voltage differencing transconductance amplifier (VDTA), two grounded capacitors and a single grounded resistor. The configuration realizes all basic filter functions (i.e. Low Pass (LP), High Pass (HP), Band Pass (BP), Notch (BR) and All Pass (AP)). The natural frequency (ω0) and bandwidth (BW) are independently tunable. The workability of proposed configuration has been verified using SPICE simulation with TSMC CMOS 0.18 μm process parameters.展开更多
A state variable method of converting single-resistance-controlled- oscillators (SRCO), into universal current-mode biquad (offering realizations of all the five standard filter functions namely, low pass, band pass, ...A state variable method of converting single-resistance-controlled- oscillators (SRCO), into universal current-mode biquad (offering realizations of all the five standard filter functions namely, low pass, band pass, high pass, notch and all pass) has been highlighted. The workability of the exemplary implementation of the derived current-mode universal biquad has been demonstrated by PSPICE simulation results based upon 0.35 μ m technology. It is expected that the proposed method can be applied to other SRCOs to generate other multifunction filter structures.展开更多
A global fast terminal sliding mode(GFTSM)-based model predictive torque control(MPTC)strategy is developed for permanent magnet synchronous motor(PMSM)drive system with only one phase current sensor.Generally two pha...A global fast terminal sliding mode(GFTSM)-based model predictive torque control(MPTC)strategy is developed for permanent magnet synchronous motor(PMSM)drive system with only one phase current sensor.Generally two phase-current sensors are indispensable for MPTC.In response to only one phase current sensor available and the change of stator resistance,a novel adaptive observer for estimating the remaining two phase currents and time-varying stator resistance is proposed to perform MPTC.Moreover,in view of the variation of system parameters and external disturbance,a new GFTSM-based speed regulator is synthesized to enhance the drive system robustness.In this paper,the GFTSM,based on sliding mode theory,employs the fast terminal sliding mode in both the reaching stage and the sliding stage.The resultant GFTSM-based MPTC PMSM drive system with single phase current sensor has excellent dynamical performance which is very close to the GFTSM-based MPTC PMSM drive system with two-phase current sensors.On the other hand,compared with proportional-integral(PI)-based and sliding mode(SM)-based MPTC PMSM drive systems,it possesses better dynamical response and stronger robustness as well as smaller total harmonic distortion(THD)index of three-phase stator currents in the presence of variation of load torque.The simulation results validate the feasibility and effectiveness of the proposed scheme.展开更多
To solve the chattering problem caused by discontinuous switching function in traditional sliding mode observer,a piecewise square root switching function with continuously varying characteristics is designed,and its ...To solve the chattering problem caused by discontinuous switching function in traditional sliding mode observer,a piecewise square root switching function with continuously varying characteristics is designed,and its stability is analyzed by using Lyapunov stability criterion.Secondly,according to the relationship among bus current,switching state and phase current,a single bus resistance sampling current reconstruction scheme without current sensors is adopted,which effectively reduces the cost of motor system.Finally,the feasibility and effectiveness of the proposed scheme are verified by simulation.展开更多
Based on the fractional order theory and sliding mode control theory,a model prediction current control(MPCC)strategy based on fractional observer is proposed for the permanent magnet synchronous motor(PMSM)driven by ...Based on the fractional order theory and sliding mode control theory,a model prediction current control(MPCC)strategy based on fractional observer is proposed for the permanent magnet synchronous motor(PMSM)driven by three-level inverter.Compared with the traditional sliding mode speed observer,the observer is very simple and eases to implement.Moreover,the observer reduces the ripple of the motor speed in high frequency range in an efficient way.To reduce the stator current ripple and improve the control performance of the torque and speed,the MPCC strategy is put forward,which can make PMSM MPCC system have better control performance,stronger robustness and good dynamic performance.The simulation results validate the feasibility and effectiveness of the proposed scheme.展开更多
An InP optical 90°hybrid based on a×4 MMI coupler with a deep ridged waveguide is designed and fabricated.The working principle of the 90°hybrid is systematically introduced.Three-dimensional beam ropag...An InP optical 90°hybrid based on a×4 MMI coupler with a deep ridged waveguide is designed and fabricated.The working principle of the 90°hybrid is systematically introduced.Three-dimensional beam ropagation method(3D BPM)is used to optimize the structure parameters of the 90°hybrid.The designed compact structure is demonatrated to have a low excess loss less than-0.15 dB,a high common mode rejection ratio better than 40 dB,and a low relative phase deviation less than±2.5°.The designed hybrid is manufactured on a sandwitched structure deposited on an InP substrate.The measured results show that the common mode rejection ratios are larger than 20 dB in a range from 1520 nm to 1580 nm.The phase deviations are less than±5°in a range from 1545 nm to 1560 nm and less than±7°across the C band.The designed 90°optical hybrid is suitable well for realizing miniaturization,high-properties,and high bandwidth of coherent receiver.展开更多
A new type of high power LED drivers is proposed by adopting an improved two-stages non-isolated configuration. In order to improve power factor and achieve accurate average current control under universal input volta...A new type of high power LED drivers is proposed by adopting an improved two-stages non-isolated configuration. In order to improve power factor and achieve accurate average current control under universal input voltages ranging from 100 Vrms to 240 Vrms, the power factor correction and average current mode control methods operating in continuous current conduction mode are designed and implemented. With the LUMILEDS emitter type LEDs, a laboratory prototype is built and measured. And from the measured results, it could be concluded that the proposed driver has many better performances such as high power factor, low current harmonic, accurate average current control and switch protection.展开更多
By applying switch-signal theory, the interaction between MOS transmission switch-ing transistor and current signal in current-mode CMOS circuits is analyzed, and the theory oftransmission current-switches which is su...By applying switch-signal theory, the interaction between MOS transmission switch-ing transistor and current signal in current-mode CMOS circuits is analyzed, and the theory oftransmission current-switches which is suitable to current-mode CMOS circuits is proposed. Thecircuits, such as ternary full-adder etc., designed by using this theory have simpler circuit struc-tures and correct logic functions. It is confirmed that this theory is efficient in guiding the logicdesign of current-mode CMOS circuits at switch level.展开更多
Based on the analysis of the basic principle of slope compensation, a high-precision adaptive slope compensation circuit for peak current mode boost DC/DC converter is designed. The circuit dynamically detects the inp...Based on the analysis of the basic principle of slope compensation, a high-precision adaptive slope compensation circuit for peak current mode boost DC/DC converter is designed. The circuit dynamically detects the input and output voltage of the boost circuit to realize automatic adjustment of the compensation amount with the change of duty ratio, which makes the ramp compensation slope optimized. The design uses a high-precision subtracter to improve the accuracy of slope compensation. While eliminating sub-slope oscillation and improving the stability of boost circuit, the negative impact of compensation on boost circuit is minimized, and the load capacity and transient response speed of boost circuit are guaranteed. The circuit is designed based on SMIC 0.18um CMOS technology, with simple structure, high reliability and easy engineering implementation. Spectre circuit simulator 17.1.0.124 64b simulation results show that the circuit has high compensation accuracy and wide input and output voltage range. When the working voltage is 3.3 V, the compensation slope can be adjusted adaptively under different duty cycles, and the minimum error between the compensation slope and the theoretical optimal compensation slope is only 0.42%.展开更多
基金sponsored by the State Grid Corporation of China Technology Project(Research on Key Technologies and Equipment Development of Micro Pumped Storage for Distributed New Energy Consumption in Distribution Networks,5400-202324196A-1-1-ZN).
文摘To enhance energy interaction among low-voltage stations(LVSs)and reduce the line loss of the distribution network,a novel operation mode of the micro-pumped storage system(mPSS)has been proposed based on the common reservoir.First,some operation modes of mPSS are analyzed,which include the separated reservoir mode(SRM)and common reservoir mode(CRM).Then,based on the SRM,and CRM,an energy mutual assistance control model between LVSs has been built to optimize energy loss.Finally,in the simulation,compared to the model without pumped storage in the LVS,the SRMand CLRMcan decrease the total energy loss by 294.377 and 432.578 kWh,respectively.The configuration of mPSS can improve the utilization rate of the new energy source generation system,and relieve the pressure of transformer capacity in the LVS.Compared with the SRM,the proposed CRM has reduced the total energy loss by 138.201 kWh,increased the new energy consumption by 161.642 kWh,and decreased the line loss by 7.271 kWh.With the efficiency of the mPSS improving,the total energy loss reduction of CRM will be 3.5 times that of SRM.Further,the CRMcan significantly reduce the reservoir capacity construction of mPSS and ismore suitable for scenarios where the capacity configuration of mPSS is limited.
文摘A novel CMOS bandgap reference is presented. The output reference of this new current mode structure can be set to an arbitrary value above the bandgap voltage of silicon,avoiding offset in application. It also overcomes the systematic mismatch of conventional current mode bandgap references. The proposed bandgap reference has been implemented in UMC 0.18μm mixed mode technology. Under the supply voltage of 1.6V, the proposed bandgap reference provides an output reference of 1.45V and consumes 27μA of supply current. Using no curvature compensation,it can reach a temperature coefficient of 23ppm/℃ from 30 to 150℃ with a line regulation of 2. 1mV/V from 1.6 to 3V and a PSRR of 40dB at DC frequency. The chip area of the bandgap reference （without pad） is 0. 088mm^2.
文摘A single power supply common-gate （CG） current mode transimpedance preamplifier （TIA） is developed with a 0.5μm GaAs PHEMT process. The amplifier has a measured - 3dB bandwidth of 7. 5GHz and a transimpedance gain of 45dBΩ. Both the input and output voltage standing wave ratios （VSWR） are less than 2 within the bandwidth. The equivalent input noise current spectral density varies from 14.3 to 22pA/√Hz, with an average value of 17. 2pA/√Hz. Having a timing jitter of 14ps and eye amplitude of about 138mV,the measured output eye diagram for 10Gb/s NRZ pseudorandom binary sequence （PRBS） is clear and satisfactory.
文摘A practical method of current mode circuit symbolic analysis using Mathematica is proposed. With the powerful symbolic manipulation capacity of Mathematica, current mode circuit symbolic analysis can be significantly simplified. The active devices are modelled by nullors. The examples of current mode filters using CCIIs are presented.
文摘An improved high-resolution current-mode sorter is presented.Its structure complexity is O(N),which is crucial to the expansion of its size,and its dynamic range is large.Only one clock signal and one reset signal are needed.No biasing signal is required.The operation point is constructed according to the input current,so it is self-adaptive,which is very important for an all-purpose component.In average value circuit,subtraction circuit,Winner-Take-All(WTA) circuit and control circuit,it has good performance even at a large input current.This sorter has high precision,high resolution and low power,as has been proved via HSPICE simulation.It can be implemented in the standard digital CMOS technology and widely used in many fields,so it is of great value in applications.
基金supported by ITER Program of China(973 Program)(No.2011GB109002)National Natural Science Foundation of China(No.11275056)Hefei University of Technology Doctor Research Foundation of China(No.2011HGBZ1292)
文摘A feedback control system is needed to restrain plasma vertical displacement in EAST （Experimental Advanced Superconducting Toknmak）. A fast control power supply excites active feedback coils, which produces a magnetic field to control the plasma＇s displacement. With the development of EAST, new demands on the new fast control power supply have led to an enhanced ability of fast response and output current, as well as a new control mode. The structure of cascaded and paralleled H-bridges can meet the demand of extended capacity, and digital control can reMize current and voltage mixed control mode. The validity of the proposed scheme is confirmed by experiments.
文摘Carbon Nano-Tube Field Effect Transistors(CNTFETs) are being widely studied as possible successors to silicon MOSFETs.Using current mode has many advantages such as performing sum operation by means of a simple wired connection.Also,direction of the current can be used to exhibit the sign of digits.It is expected that the advantages of current mode approaches will become even more important with increased speed requirements and decreased supply voltage.In this paper,we present five new circuit designs for differential absolute value in current mode logic which have been simulated by CNTFET model.The considered base current for this model is 2 μA and supply voltage is 0.9 V.In all of our designs we used N-type CNTFET current mirrors which operate as truncated difference circuits.The operation of Differential Absolute Value circuit calculates the difference between two input currents and our circuit designs are operate in 8 logic levels.
基金Supported by the National Natural Science Foundation of China(51076014)the Research Fund for the Doctoral Program of Higher Education(20101101110011)
文摘Influence of eddy current on transient characteristics of common rail injector solenoid valve was studied in this paper. Experimental investigations of drive current and power source volt- age of both drive current ascending and descending process were conducted on a common rail injec- tor solenoid valve. A new discretizing calculation method of solenoid valve flux linkage was put for- ward for the first time based on the experimental results and drive circuit principle, and flux linkage of both drive current ascending and descending process were evaluated. New inductance calculation methods for drive current ascending and descending process respectively were also presented. Influ- ence of parasitic inductance was evaluated. Results indicate that the air gap, under which the transi- ent flux linkage of the solenoid valve is the biggest, varies with drive current due to eddy current. Flux linkage of drive current descending process is bigger than that of drive current ascending process under the same drive current and the same air gap width. Eddy current can reduce the delay between the time that drive current begins to descend and the time that armature begins to move downward. Inductance of drive current descending process is bigger than that of drive current as- cending process over larger scope of drive current, but the difference becomes smaller with the in- creasing of air gap width. The differences of both flux linkage and inductance between drive current ascending and descending process are caused by the eddy current in core and armature materials.
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2008AA03Z402)the National Natural Science Foundation of China (Grant No. 61076044)the Natural Science Foundation of Beijing,China(Grant Nos. 4092007 and 4102003)
文摘A multi-hole vertical-cavity surface-emitting laser （VCSEL） operating in stable single mode with a low threshold current was produced by introducing multi-leaf scallop holes on the top distributed Bragg-refleetor of an oxidation- confined 850 nm VCSEL. The single-mode output power of 2.6 mW, threshold current of 0.6 mA, full width of half maximum lasing spectrum of less than 0.1 nm, side mode suppression ratio of 28.4 dB, and far-field divergence angle of about 10% are obtained. The effects of different hole depths on the optical characteristics are simulated and analysed, including far-field divergence, spectrum and lateral cavity mode. The single-mode performance of this multi-hole device is attributed to the large radiation loss from the inter hole spacing and the scattering loss at the bottom of the holes, particularly for higher order modes.
基金supported by National Natural Science Foundation of China(Nos.11275041 and 11105065)
文摘Based on a linearized MHD model, the effect of equilibrium current profiles on external kink modes in tokamaks is studied by MARS code. Three types of equilibrium current profiles are adopted in this work. Firstly, a set of parabolic equilibrium current profiles are chosen. In these profiles the maximum current values in the center of the plasma are fixed, and the currents have different gradient and jump at the plasma boundary. The effects of the current gradient and jump on the growth rate of external kink mode are investigated. It is found that the current jump which causes the q profiles to change plays an important role in the externM kink modes in tokamaks. Secondly, a set of step equilibrium current profiles with different jump positions are chosen. The effect of jump position on external kink modes is discussed. Thirdly, a set of parabolic equilibrium current profiles with current bumps are chosen for the case of off-axis heating. The effects of height~ width and position of the current bumps on external kink modes are analyzed. The fiat equilibrium current profiles are disadvantageous for the MHD stabilities of tokamaks, because of the large current jump at the plasma edge. The peaked equilibrium current profiles and a large and localized current bump near the plasma edge benefit the MHD stabilities of tokamaks.
文摘This paper presents a new current-mode single input multi output (SIMO) type biquad employing one voltage differencing transconductance amplifier (VDTA), two grounded capacitors and a single grounded resistor. The configuration realizes all basic filter functions (i.e. Low Pass (LP), High Pass (HP), Band Pass (BP), Notch (BR) and All Pass (AP)). The natural frequency (ω0) and bandwidth (BW) are independently tunable. The workability of proposed configuration has been verified using SPICE simulation with TSMC CMOS 0.18 μm process parameters.
文摘A state variable method of converting single-resistance-controlled- oscillators (SRCO), into universal current-mode biquad (offering realizations of all the five standard filter functions namely, low pass, band pass, high pass, notch and all pass) has been highlighted. The workability of the exemplary implementation of the derived current-mode universal biquad has been demonstrated by PSPICE simulation results based upon 0.35 μ m technology. It is expected that the proposed method can be applied to other SRCOs to generate other multifunction filter structures.
基金supported by the National Natural Science Foundation of China(61463025).
文摘A global fast terminal sliding mode(GFTSM)-based model predictive torque control(MPTC)strategy is developed for permanent magnet synchronous motor(PMSM)drive system with only one phase current sensor.Generally two phase-current sensors are indispensable for MPTC.In response to only one phase current sensor available and the change of stator resistance,a novel adaptive observer for estimating the remaining two phase currents and time-varying stator resistance is proposed to perform MPTC.Moreover,in view of the variation of system parameters and external disturbance,a new GFTSM-based speed regulator is synthesized to enhance the drive system robustness.In this paper,the GFTSM,based on sliding mode theory,employs the fast terminal sliding mode in both the reaching stage and the sliding stage.The resultant GFTSM-based MPTC PMSM drive system with single phase current sensor has excellent dynamical performance which is very close to the GFTSM-based MPTC PMSM drive system with two-phase current sensors.On the other hand,compared with proportional-integral(PI)-based and sliding mode(SM)-based MPTC PMSM drive systems,it possesses better dynamical response and stronger robustness as well as smaller total harmonic distortion(THD)index of three-phase stator currents in the presence of variation of load torque.The simulation results validate the feasibility and effectiveness of the proposed scheme.
文摘To solve the chattering problem caused by discontinuous switching function in traditional sliding mode observer,a piecewise square root switching function with continuously varying characteristics is designed,and its stability is analyzed by using Lyapunov stability criterion.Secondly,according to the relationship among bus current,switching state and phase current,a single bus resistance sampling current reconstruction scheme without current sensors is adopted,which effectively reduces the cost of motor system.Finally,the feasibility and effectiveness of the proposed scheme are verified by simulation.
基金National Natural Science Foundation of China(No.61463025)Opening Foundation of Key Laboratory of Opto-Technology and Intelligent Control(Lanzhou Jiaotong University),Ministry of Education(No.KFKT2018-8)。
文摘Based on the fractional order theory and sliding mode control theory,a model prediction current control(MPCC)strategy based on fractional observer is proposed for the permanent magnet synchronous motor(PMSM)driven by three-level inverter.Compared with the traditional sliding mode speed observer,the observer is very simple and eases to implement.Moreover,the observer reduces the ripple of the motor speed in high frequency range in an efficient way.To reduce the stator current ripple and improve the control performance of the torque and speed,the MPCC strategy is put forward,which can make PMSM MPCC system have better control performance,stronger robustness and good dynamic performance.The simulation results validate the feasibility and effectiveness of the proposed scheme.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB0402404)the Beijing Natural Science Foundation,China(Grant No.4194093)the National Natural Science Foundation of China(Grant Nos.61635010,61674136,and 61435002).
文摘An InP optical 90°hybrid based on a×4 MMI coupler with a deep ridged waveguide is designed and fabricated.The working principle of the 90°hybrid is systematically introduced.Three-dimensional beam ropagation method(3D BPM)is used to optimize the structure parameters of the 90°hybrid.The designed compact structure is demonatrated to have a low excess loss less than-0.15 dB,a high common mode rejection ratio better than 40 dB,and a low relative phase deviation less than±2.5°.The designed hybrid is manufactured on a sandwitched structure deposited on an InP substrate.The measured results show that the common mode rejection ratios are larger than 20 dB in a range from 1520 nm to 1580 nm.The phase deviations are less than±5°in a range from 1545 nm to 1560 nm and less than±7°across the C band.The designed 90°optical hybrid is suitable well for realizing miniaturization,high-properties,and high bandwidth of coherent receiver.
文摘A new type of high power LED drivers is proposed by adopting an improved two-stages non-isolated configuration. In order to improve power factor and achieve accurate average current control under universal input voltages ranging from 100 Vrms to 240 Vrms, the power factor correction and average current mode control methods operating in continuous current conduction mode are designed and implemented. With the LUMILEDS emitter type LEDs, a laboratory prototype is built and measured. And from the measured results, it could be concluded that the proposed driver has many better performances such as high power factor, low current harmonic, accurate average current control and switch protection.
基金Supported by National Natural Science Foundation of China
文摘By applying switch-signal theory, the interaction between MOS transmission switch-ing transistor and current signal in current-mode CMOS circuits is analyzed, and the theory oftransmission current-switches which is suitable to current-mode CMOS circuits is proposed. Thecircuits, such as ternary full-adder etc., designed by using this theory have simpler circuit struc-tures and correct logic functions. It is confirmed that this theory is efficient in guiding the logicdesign of current-mode CMOS circuits at switch level.
文摘Based on the analysis of the basic principle of slope compensation, a high-precision adaptive slope compensation circuit for peak current mode boost DC/DC converter is designed. The circuit dynamically detects the input and output voltage of the boost circuit to realize automatic adjustment of the compensation amount with the change of duty ratio, which makes the ramp compensation slope optimized. The design uses a high-precision subtracter to improve the accuracy of slope compensation. While eliminating sub-slope oscillation and improving the stability of boost circuit, the negative impact of compensation on boost circuit is minimized, and the load capacity and transient response speed of boost circuit are guaranteed. The circuit is designed based on SMIC 0.18um CMOS technology, with simple structure, high reliability and easy engineering implementation. Spectre circuit simulator 17.1.0.124 64b simulation results show that the circuit has high compensation accuracy and wide input and output voltage range. When the working voltage is 3.3 V, the compensation slope can be adjusted adaptively under different duty cycles, and the minimum error between the compensation slope and the theoretical optimal compensation slope is only 0.42%.
