Reliability is a persistent challenge in power electronics, with component failures significantly compromising system performance. Capacitors, widely used in power converters for filtering, contribute to approximately...Reliability is a persistent challenge in power electronics, with component failures significantly compromising system performance. Capacitors, widely used in power converters for filtering, contribute to approximately 30% of failures, predominantly due to electrochemical corrosion leading to capacitance degradation and catastrophic breakdowns. This paper presents a novel capacitor-free solid-state power filter(SSPF) for three-phase inverters, offering a transformative approach to mitigate reliability issues associated with conventional inductor-capacitor(LC) and active output filters(AOFs). Unlike AOFs, which depend on compact LC structures, the SSPF eliminates capacitors entirely, circumventing their inherent failure modes. Leveraging advanced solid-state devices and transformer technology, the SSPF achieves superior filtering performance, enhances system reliability, and significantly reduces component count, utilizing half the metal-oxidesemiconductor field effect transistor(MOSFET) switches required by AOFs. This design not only lowers costs but also improves efficiency. Simulation and experimental results demonstrate the SSPF's capability to deliver a sinusoidal output voltage at the fundamental frequency. These attributes position the SSPF as a robust, cost-effective, and innovative solution for modern power electronics applications.展开更多
Noises always disturb the control effect of an environment test especially in multi-input multi-output(MIMO) systems. If the frequency response function matrices are ill-conditioned, the noises in the driving forces w...Noises always disturb the control effect of an environment test especially in multi-input multi-output(MIMO) systems. If the frequency response function matrices are ill-conditioned, the noises in the driving forces will be amplified and the response spectral lines may awfully exceed their tolerances. Most of the major biases between the response spectra and the reference spectra are produced by the amplified noises. However, ordinary control algorithms can hardly reduce the level of noises. The influences of the noises on both the auto- and cross-power spectra are analyzed in this paper. As a conventional frequency domain method on the inverse problem, the Tikhonov filter is adopted in the environment test to suppress the exceeding spectral lines. By altering regularization parameters gradually, the auto-power spectra can be improved in a closed control loop. Instead of using the traditional way of selecting regularization parameters, we observe the coherence change to estimate noise eliminations. Incidentally, the requirement of coherence control can be realized. The errors of the phase are then studied and a phase control algorithm is introduced at the end as a supplement of cross-power spectra control. The Tikhonov filter and the proposed phase control algorithm are tested numerically and experimentally. The results show that the noises in the vicinity of lightly damped resonant peaks are more stubborn. The response spectra are able to be greatly improved by the combination of these two methods.展开更多
In this paper, a new observation equation of non-Gaussian frequency selective fading Bell Labs layered space time （BLAST） architecture system is proposed, which is used for frequency selective fading channels and no...In this paper, a new observation equation of non-Gaussian frequency selective fading Bell Labs layered space time （BLAST） architecture system is proposed, which is used for frequency selective fading channels and non-Gaussian noise in an application environment of BLAST system. With othogonal matrix triangularization （QR decomposition） of the channel matrix, the static observation equation of frequency selective fading BLAST system is transformed into a dynamic state space model, and then the particle filter is used for space-time layered detection. Making the full use of the finite alphabet of the digital modulation communication signal, the optimal proposal distribution can be chosen to produce particle and update the weight. Incorporated with current method of reducing error propagation, a new space-time layered detection algorithm is proposed. Simulation result shows the validity of the proposed algorithm.展开更多
Converters rely on passive filtering as a crucial element due to the high-frequency operational characteristics of power electronics.Traditional filtering methods involve a dual inductor-capacitor(LC)cell or an induct...Converters rely on passive filtering as a crucial element due to the high-frequency operational characteristics of power electronics.Traditional filtering methods involve a dual inductor-capacitor(LC)cell or an inductor-capacitor-inductor(LCL)T-circuit.However,capacitors are susceptible to wear-out mechanisms and failure modes.Nevertheless,the necessity for monitoring and regular replacement adds to an elevated cost of ownership for such systems.The utilization of an active output power filter can be used to diminish the dimensions of the LC filter and the electrolytic dc-link capacitor,even though the inclusion of capacitors remains an indispensable part of the system.This paper introduces capacitorless solid-state power filter(SSPF)for single-phase dc-ac converters.The proposed configuration is capable of generating a sinusoidal ac voltage without relying on capacitors.The proposed filter,composed of a planar transformer and an H-bridge converter operating at high frequency,injects voltage harmonics to attain a sinusoidal output voltage.The design parameters of the planar transformer are incorporated,and the impact of magnetizing and leakage inductances on the operation of the SSPF is illustrated.Theoretical analysis,supported by simulation and experimental results,are provided for a design example for a single-phase system.The total harmonic distortion observed in the output voltage is well below the IEEE 519 standard.The system operation is experimentally tested under both steady-state and dynamic conditions.A comparison with existing technology is presented,demonstrating that the proposed topology reduces the passive components used for filtering.展开更多
To mitigate the effects of the previous symbol decision errors of a decision-feedback （DF） equalizer on the current decision, a particle filter （PF） based DF equalizer for frequency selective multiple-input-multip...To mitigate the effects of the previous symbol decision errors of a decision-feedback （DF） equalizer on the current decision, a particle filter （PF） based DF equalizer for frequency selective multiple-input-multiple-output （MIMO） channel is proposed. On the basis of the analyses of DF equalization for the MIMO wireless system, it is found that a stochastic interference cancellation （IC） scheme can be employed to prevent the error propagation in a severe space-time interference scenario. This is because the random rather than the deterministic scheme can reduce the probability of an error decision even if an error decision occurs. Besides, the signal-to-interference-plus-noise ratio （SINR） based IC order, which is obtained via pilot, can guarantee the optimality of the cancellation. The bit error rate （BER） performance of the proposed scheme is verified through simulation experiments under different multipath interference environment.展开更多
A kind of adaptive color noise Kalman filtering approach based on the correlative method of the system output is proposed to solve the cephalometric images of stomatology. This approach builds the color noise Kalman f...A kind of adaptive color noise Kalman filtering approach based on the correlative method of the system output is proposed to solve the cephalometric images of stomatology. This approach builds the color noise Kalman filtering model by adopting the equivalent measurement equation in order to aviod complicated computation and expansion of the dimension of the filter. It is also unnecessary to know the variance of measurement noise beforehand so that it is closer to the actual situation. The results of several experiments are presented to demonstrate the feasibility and good performance of this approach.展开更多
A complete state variable current-mode biquadratic filter built by duo-output CCII (DOCCII) with variable current gain is presented. All the coefficients of the filter can be independently tuned through the variable c...A complete state variable current-mode biquadratic filter built by duo-output CCII (DOCCII) with variable current gain is presented. All the coefficients of the filter can be independently tuned through the variable current gain factors of the DOCCII. Based on the principles upon which the general biquadratic filter was constructed, a universal electronically tunable current-mode filter is proposed which implements the low-pass, high-pass, band-pass, band-suppress and all-pass second order transfer functions simultaneously. The PSPICE simulations of frequency responses of second-order filter of are also given.展开更多
In this manuscript we present a current mode biquad using one dual output-voltage differencing buffered amplifier (DO-VDBA) and four passive components (2 grounded capacitors and 2 resistors). The proposed circuit off...In this manuscript we present a current mode biquad using one dual output-voltage differencing buffered amplifier (DO-VDBA) and four passive components (2 grounded capacitors and 2 resistors). The proposed circuit offers very low active and passive sensitivity. The filter presented here is electronically tunable, frequency of oscillation (FO) can be tuned by controlling transconductance (gm) by varying the bias current (IB) of the circuit. The workability of proposed circuit is tested using PSPICE with 180 nm TSMC CMOS process parameters.展开更多
A space-time coded multiple-input multiple-output orthogonal frequency-division multiplexing （MIMO-OFDM） system is considered as a solution to the future wideband wireless communication system. This paper proposes a...A space-time coded multiple-input multiple-output orthogonal frequency-division multiplexing （MIMO-OFDM） system is considered as a solution to the future wideband wireless communication system. This paper proposes an extended Kalman filtering-based （EKF-based） channel estimation method for space-time coded MIMO-OFDM systems. The proposed method can exploit pilot symbols and an extended Kalman filter to estimate channel without any prior knowledge of channel statistics. In comparison with the least square （LS） and the least mean square （LMS） methods, the EKF-based approach has a better performance in theory. Computer simulations demonstrate the proposed method outperforms the LS and LMS methods. Therefore it can offer draznatic system performance improvement at a modest cost of computational complexity.展开更多
国际原子能机构(International Atomic Energy Agency,IAEA)与美国医学物理学家协会(American Association of Physicists in Medicine,AAPM)联合制定的外照射光子束小野静态射野剂量学操作规程(TRS-483)中提供的小野射野输出修正因子(k...国际原子能机构(International Atomic Energy Agency,IAEA)与美国医学物理学家协会(American Association of Physicists in Medicine,AAPM)联合制定的外照射光子束小野静态射野剂量学操作规程(TRS-483)中提供的小野射野输出修正因子(k_(Qclin,Qref)^(fclin,fref))未考虑均整模式(Flattening Filter,FF)、非均整模式(Flattening Filter Free,FFF)束流间差异,对于电离室在相同射野条件下测量的小野射野输出因子(Ω^(fclin,fref) _(Qclin,Qref))给出相同修正系数,可能引入超过1%的偏差。据此,提出利用蒙特卡罗模拟细化电离室k_(Qclin,Qref)^(fclin,fref)的方法,对FF、FFF束流下电离室小野测量数据进行分别修正,进一步提升临床小野剂量测量准确性。基于EGSnrc构建Elekta Synergy加速器机头模型,建立电离室k_(Qclin,Qref)^(fclin,fref)模拟方法。通过电离室在FF束流不同射野条件下Ω^(fclin,fref)_(Qclin,Qref)的测量及修正,验证蒙特卡罗计算模型,并分别计算了6款小灵敏体积电离室在FF、FFF束流不同射野范围(0.8 cm×0.8 cm~10 cm×10 cm)的k_(Qclin,Qref)^(fclin,fref)。研究发现,同一电离室在FF、FFF束流不同射野条件下计算的k_(Qclin,Qref)^(fclin,fref)存在明显差异,其中PTW 31015在FFF模式下计算的k_(Qclin,Qref)^(fclin,fref)与FF模式计算结果相比最大偏差超过1.02%。因此,通过细化电离室k_(Qclin,Qref)^(fclin,fref)的方法能够有效提升临床小野水吸收剂量测量准确性。展开更多
基金curruntly supported by the Purdue University Office of Technology Commercialization under Track Code (PRF 71167-01)。
文摘Reliability is a persistent challenge in power electronics, with component failures significantly compromising system performance. Capacitors, widely used in power converters for filtering, contribute to approximately 30% of failures, predominantly due to electrochemical corrosion leading to capacitance degradation and catastrophic breakdowns. This paper presents a novel capacitor-free solid-state power filter(SSPF) for three-phase inverters, offering a transformative approach to mitigate reliability issues associated with conventional inductor-capacitor(LC) and active output filters(AOFs). Unlike AOFs, which depend on compact LC structures, the SSPF eliminates capacitors entirely, circumventing their inherent failure modes. Leveraging advanced solid-state devices and transformer technology, the SSPF achieves superior filtering performance, enhances system reliability, and significantly reduces component count, utilizing half the metal-oxidesemiconductor field effect transistor(MOSFET) switches required by AOFs. This design not only lowers costs but also improves efficiency. Simulation and experimental results demonstrate the SSPF's capability to deliver a sinusoidal output voltage at the fundamental frequency. These attributes position the SSPF as a robust, cost-effective, and innovative solution for modern power electronics applications.
基金supported by the Fundamental Research Funds for the Central Universities (No. NS2015008)the corresponding work was performed in the State Key Laboratory of Mechanics and Control of Mechanical Structures
文摘Noises always disturb the control effect of an environment test especially in multi-input multi-output(MIMO) systems. If the frequency response function matrices are ill-conditioned, the noises in the driving forces will be amplified and the response spectral lines may awfully exceed their tolerances. Most of the major biases between the response spectra and the reference spectra are produced by the amplified noises. However, ordinary control algorithms can hardly reduce the level of noises. The influences of the noises on both the auto- and cross-power spectra are analyzed in this paper. As a conventional frequency domain method on the inverse problem, the Tikhonov filter is adopted in the environment test to suppress the exceeding spectral lines. By altering regularization parameters gradually, the auto-power spectra can be improved in a closed control loop. Instead of using the traditional way of selecting regularization parameters, we observe the coherence change to estimate noise eliminations. Incidentally, the requirement of coherence control can be realized. The errors of the phase are then studied and a phase control algorithm is introduced at the end as a supplement of cross-power spectra control. The Tikhonov filter and the proposed phase control algorithm are tested numerically and experimentally. The results show that the noises in the vicinity of lightly damped resonant peaks are more stubborn. The response spectra are able to be greatly improved by the combination of these two methods.
文摘In this paper, a new observation equation of non-Gaussian frequency selective fading Bell Labs layered space time （BLAST） architecture system is proposed, which is used for frequency selective fading channels and non-Gaussian noise in an application environment of BLAST system. With othogonal matrix triangularization （QR decomposition） of the channel matrix, the static observation equation of frequency selective fading BLAST system is transformed into a dynamic state space model, and then the particle filter is used for space-time layered detection. Making the full use of the finite alphabet of the digital modulation communication signal, the optimal proposal distribution can be chosen to produce particle and update the weight. Incorporated with current method of reducing error propagation, a new space-time layered detection algorithm is proposed. Simulation result shows the validity of the proposed algorithm.
文摘Converters rely on passive filtering as a crucial element due to the high-frequency operational characteristics of power electronics.Traditional filtering methods involve a dual inductor-capacitor(LC)cell or an inductor-capacitor-inductor(LCL)T-circuit.However,capacitors are susceptible to wear-out mechanisms and failure modes.Nevertheless,the necessity for monitoring and regular replacement adds to an elevated cost of ownership for such systems.The utilization of an active output power filter can be used to diminish the dimensions of the LC filter and the electrolytic dc-link capacitor,even though the inclusion of capacitors remains an indispensable part of the system.This paper introduces capacitorless solid-state power filter(SSPF)for single-phase dc-ac converters.The proposed configuration is capable of generating a sinusoidal ac voltage without relying on capacitors.The proposed filter,composed of a planar transformer and an H-bridge converter operating at high frequency,injects voltage harmonics to attain a sinusoidal output voltage.The design parameters of the planar transformer are incorporated,and the impact of magnetizing and leakage inductances on the operation of the SSPF is illustrated.Theoretical analysis,supported by simulation and experimental results,are provided for a design example for a single-phase system.The total harmonic distortion observed in the output voltage is well below the IEEE 519 standard.The system operation is experimentally tested under both steady-state and dynamic conditions.A comparison with existing technology is presented,demonstrating that the proposed topology reduces the passive components used for filtering.
基金Supported by National Natural Science Foundation of China （60674036）, the Science and Technical Development Plan of Shandong Province （2004GG4204014）, the Program for New Century Excellent Talents in University of China （NCET-07-0513）, the Key Science and Technique Foundation of Ministry of Education of China （108079）, and the Excellent Young and Middle-aged Scientist Award of Shandong Province of China （2007BS01010）
基金National Natural Science Foundation of China （60674036, 60974003）, the Natural Science Foundation for Distinguished Young Scholar of Shandong Province of China （JQ200919）, the Program for New Century Excellent Talents in University of China （NCET-07-0513）, the Key Science and Technique Foundation of Ministry of Education of China （108079）, the Excellent Young and Middle-Aged Scientist Award Grant of Shandong Province of China （2007BS01010）
基金supported in part by the National Natural Science Foundation of China (60672047)the Shanghai Postdoctoral Scientific Program (05R214110).
文摘To mitigate the effects of the previous symbol decision errors of a decision-feedback （DF） equalizer on the current decision, a particle filter （PF） based DF equalizer for frequency selective multiple-input-multiple-output （MIMO） channel is proposed. On the basis of the analyses of DF equalization for the MIMO wireless system, it is found that a stochastic interference cancellation （IC） scheme can be employed to prevent the error propagation in a severe space-time interference scenario. This is because the random rather than the deterministic scheme can reduce the probability of an error decision even if an error decision occurs. Besides, the signal-to-interference-plus-noise ratio （SINR） based IC order, which is obtained via pilot, can guarantee the optimality of the cancellation. The bit error rate （BER） performance of the proposed scheme is verified through simulation experiments under different multipath interference environment.
基金Supported by the High Technology Research and Development Programme of China
文摘A kind of adaptive color noise Kalman filtering approach based on the correlative method of the system output is proposed to solve the cephalometric images of stomatology. This approach builds the color noise Kalman filtering model by adopting the equivalent measurement equation in order to aviod complicated computation and expansion of the dimension of the filter. It is also unnecessary to know the variance of measurement noise beforehand so that it is closer to the actual situation. The results of several experiments are presented to demonstrate the feasibility and good performance of this approach.
文摘A complete state variable current-mode biquadratic filter built by duo-output CCII (DOCCII) with variable current gain is presented. All the coefficients of the filter can be independently tuned through the variable current gain factors of the DOCCII. Based on the principles upon which the general biquadratic filter was constructed, a universal electronically tunable current-mode filter is proposed which implements the low-pass, high-pass, band-pass, band-suppress and all-pass second order transfer functions simultaneously. The PSPICE simulations of frequency responses of second-order filter of are also given.
文摘In this manuscript we present a current mode biquad using one dual output-voltage differencing buffered amplifier (DO-VDBA) and four passive components (2 grounded capacitors and 2 resistors). The proposed circuit offers very low active and passive sensitivity. The filter presented here is electronically tunable, frequency of oscillation (FO) can be tuned by controlling transconductance (gm) by varying the bias current (IB) of the circuit. The workability of proposed circuit is tested using PSPICE with 180 nm TSMC CMOS process parameters.
基金Project supported by the National Natural Science Foundation of China （Grant No.60572157）, and the National High- Technology Research and Development Program of China （Grant No.2003AA123310）
文摘A space-time coded multiple-input multiple-output orthogonal frequency-division multiplexing （MIMO-OFDM） system is considered as a solution to the future wideband wireless communication system. This paper proposes an extended Kalman filtering-based （EKF-based） channel estimation method for space-time coded MIMO-OFDM systems. The proposed method can exploit pilot symbols and an extended Kalman filter to estimate channel without any prior knowledge of channel statistics. In comparison with the least square （LS） and the least mean square （LMS） methods, the EKF-based approach has a better performance in theory. Computer simulations demonstrate the proposed method outperforms the LS and LMS methods. Therefore it can offer draznatic system performance improvement at a modest cost of computational complexity.
文摘国际原子能机构(International Atomic Energy Agency,IAEA)与美国医学物理学家协会(American Association of Physicists in Medicine,AAPM)联合制定的外照射光子束小野静态射野剂量学操作规程(TRS-483)中提供的小野射野输出修正因子(k_(Qclin,Qref)^(fclin,fref))未考虑均整模式(Flattening Filter,FF)、非均整模式(Flattening Filter Free,FFF)束流间差异,对于电离室在相同射野条件下测量的小野射野输出因子(Ω^(fclin,fref) _(Qclin,Qref))给出相同修正系数,可能引入超过1%的偏差。据此,提出利用蒙特卡罗模拟细化电离室k_(Qclin,Qref)^(fclin,fref)的方法,对FF、FFF束流下电离室小野测量数据进行分别修正,进一步提升临床小野剂量测量准确性。基于EGSnrc构建Elekta Synergy加速器机头模型,建立电离室k_(Qclin,Qref)^(fclin,fref)模拟方法。通过电离室在FF束流不同射野条件下Ω^(fclin,fref)_(Qclin,Qref)的测量及修正,验证蒙特卡罗计算模型,并分别计算了6款小灵敏体积电离室在FF、FFF束流不同射野范围(0.8 cm×0.8 cm~10 cm×10 cm)的k_(Qclin,Qref)^(fclin,fref)。研究发现,同一电离室在FF、FFF束流不同射野条件下计算的k_(Qclin,Qref)^(fclin,fref)存在明显差异,其中PTW 31015在FFF模式下计算的k_(Qclin,Qref)^(fclin,fref)与FF模式计算结果相比最大偏差超过1.02%。因此,通过细化电离室k_(Qclin,Qref)^(fclin,fref)的方法能够有效提升临床小野水吸收剂量测量准确性。
