This paper presents a modified modular multilevel cascaded converter based on a triple star bridge cell(MMCCTSBC)for integrating different types of energy storage to form a hybrid energy storage system(HESS).The propo...This paper presents a modified modular multilevel cascaded converter based on a triple star bridge cell(MMCCTSBC)for integrating different types of energy storage to form a hybrid energy storage system(HESS).The proposed HESS comprises battery energy storage,supercapacitor energy storage and a doubly-fed induction machine(DFIM)based variable speed pump storage(VSPS).Different low-rated energy storage units can be intermixed in this converter to form an HESS.This is possible due to the modular structure of the modified converter and provides an advantage in a high-power energy storage system.To validate the performance of HESS,real-time power variation data is accumulated from online sources and a weighted median filter(WMF)is employed for generating appropriate references for battery energy storage system(BESS)and supercapacitor storage to mitigate both low frequency and high-frequency power variations.Here,the control approach permits independent regulation of grid current and DFIM current through the modified MMCC-TSBC converter.The simulation and experimental results validate the effectiveness of the control scheme for the proposed HESS.展开更多
New circuit implementations of electronically tunable first and second order allpass filter (AP) structures using a Multiplication Mode Current Conveyor (MMCC) building block are presented. The control voltage (V) of ...New circuit implementations of electronically tunable first and second order allpass filter (AP) structures using a Multiplication Mode Current Conveyor (MMCC) building block are presented. The control voltage (V) of the MMCC tunes the desired phase (θ) while the time constant (τ) is adjustable by a Differential Voltage Current Conveyor Transconductance Amplifier (DVCCTA)-based synthetic lossless grounded inductor (L). The circuits are analyzed taking into account the device imperfections which show low active sensitivity features of the designs. The effects of port transfer error (ε) and that of the parasitic capacitances of the active devices had been meticulously examined which indicated that certain deviations in nominal design equations occur;these however, could be minimized with appropriate choice of the circuit passive components. Readily available AD-844 type Current Feedback Amplifier (CFA) elements are utilized for the topology implementation. Satisfactory test results on electronic θ-tunability, upto about 300 KHz, had been verified by PSPICE simulation and with hardware experimentation.展开更多
Using the new building block Multiplication-Mode Current Conveyor (MMCC), some inverting/non-inverting type integrator and differentiator designs are presented, wherein the time constant (τ) is tuned electronically. ...Using the new building block Multiplication-Mode Current Conveyor (MMCC), some inverting/non-inverting type integrator and differentiator designs are presented, wherein the time constant (τ) is tuned electronically. The MMCC is implemented by a readily available chip-level configuration using a multiplier (ICL 8013) and a current feedback amplifier (AD-844 IC) CFA. Detailed analysis, taking into account the device non-idealities, had been carried out that indicates slight deviations affecting the values of the nominal time constant but the design is practically insensitive to the port mismatch errors (ε). Satisfactory response on wave conversion, for signal frequencies up to 600 Khz had been verified with both hardware circuit test and PSPICE macromodel simulation.展开更多
This paper presents a novel inter-cluster direct current(DC)capacitor voltage balancing control scheme for the single-star configured modular multilevel cascaded converter(MMCC)-based static synchronous compensator(ST...This paper presents a novel inter-cluster direct current(DC)capacitor voltage balancing control scheme for the single-star configured modular multilevel cascaded converter(MMCC)-based static synchronous compensator(STATCOM)under unbalanced grid voltage.The negative-sequence component of grid voltage at the point of common connection(PCC)causes unbalanced active power flow in the phase limbs of converter.This leads to the imbalance of DC voltages of the sub-module capacitors across the MMCC phases,and consequently,the malfunction of converter.The proposed solution is to inject both negative-sequence current(NSC)and zero-sequence voltage(ZSV)into the phase limbs of MMCC.A quantification factor Qf is used to achieve the sharing of inter-cluster active pow-er between the NSC and ZSV injection methods.Accurate determination of the quantification factor has been presented.In addition to maintaining the DC voltages of sub-module capacitor across the MMCC phases balanced,it also prevents the overcurrent and overvoltage of converter by injecting NSC and ZSV with the right proportion.The control scheme is validated on a 3.54 kV 1.2 MVA power system using MMCC-based STATCOM with 3-level bridge cells as sub-modules.The results show that the proposed scheme provides superior effectiveness in eliminating the voltage imbalance of DC capacitor in the phase limb while maintaining low voltage and current ratings.展开更多
文中提出一种新型单级式隔离型模块化多电平级联变换器(isolated modular multilevel cascade converter,I-MMCC),其具有中压三相交流(medium voltage three-phase AC,MVAC_((T-P)))、中压单相交流(medium voltage single phase AC,MVAC...文中提出一种新型单级式隔离型模块化多电平级联变换器(isolated modular multilevel cascade converter,I-MMCC),其具有中压三相交流(medium voltage three-phase AC,MVAC_((T-P)))、中压单相交流(medium voltage single phase AC,MVAC_((S-P)))和低压直流(low voltage DC,LVDC)3种电压端口。该变换器可实现从LVDC到MVAC的单级式功率变换,MVAC_((T-P))与MVAC_((S-P))电压端口能够实现同频或变频的AC-AC功率自由变换,其单极性调制策略可避免隔离型AC-AC矩阵变换器双向开关管换流暂态过程中出现的电压尖峰等问题。首先,介绍I-MMCC子模块拓扑结构与调制策略,并建立子模块及单相I-MMCC平均等效数学模型;其次,分析MVAC_((T-P))与MVAC_((S-P))端口变频–变压工作原理、稳态功率与端口特性,对单相交流端口基于正交虚拟电路概念,建立控制模型,并推导出MVAC_((S-P))、MVAC_((T-P))端口功率约束关系。最后,通过搭建一套实验样机验证所提出拓扑结构的有效性和优越性。展开更多
文摘This paper presents a modified modular multilevel cascaded converter based on a triple star bridge cell(MMCCTSBC)for integrating different types of energy storage to form a hybrid energy storage system(HESS).The proposed HESS comprises battery energy storage,supercapacitor energy storage and a doubly-fed induction machine(DFIM)based variable speed pump storage(VSPS).Different low-rated energy storage units can be intermixed in this converter to form an HESS.This is possible due to the modular structure of the modified converter and provides an advantage in a high-power energy storage system.To validate the performance of HESS,real-time power variation data is accumulated from online sources and a weighted median filter(WMF)is employed for generating appropriate references for battery energy storage system(BESS)and supercapacitor storage to mitigate both low frequency and high-frequency power variations.Here,the control approach permits independent regulation of grid current and DFIM current through the modified MMCC-TSBC converter.The simulation and experimental results validate the effectiveness of the control scheme for the proposed HESS.
文摘New circuit implementations of electronically tunable first and second order allpass filter (AP) structures using a Multiplication Mode Current Conveyor (MMCC) building block are presented. The control voltage (V) of the MMCC tunes the desired phase (θ) while the time constant (τ) is adjustable by a Differential Voltage Current Conveyor Transconductance Amplifier (DVCCTA)-based synthetic lossless grounded inductor (L). The circuits are analyzed taking into account the device imperfections which show low active sensitivity features of the designs. The effects of port transfer error (ε) and that of the parasitic capacitances of the active devices had been meticulously examined which indicated that certain deviations in nominal design equations occur;these however, could be minimized with appropriate choice of the circuit passive components. Readily available AD-844 type Current Feedback Amplifier (CFA) elements are utilized for the topology implementation. Satisfactory test results on electronic θ-tunability, upto about 300 KHz, had been verified by PSPICE simulation and with hardware experimentation.
文摘Using the new building block Multiplication-Mode Current Conveyor (MMCC), some inverting/non-inverting type integrator and differentiator designs are presented, wherein the time constant (τ) is tuned electronically. The MMCC is implemented by a readily available chip-level configuration using a multiplier (ICL 8013) and a current feedback amplifier (AD-844 IC) CFA. Detailed analysis, taking into account the device non-idealities, had been carried out that indicates slight deviations affecting the values of the nominal time constant but the design is practically insensitive to the port mismatch errors (ε). Satisfactory response on wave conversion, for signal frequencies up to 600 Khz had been verified with both hardware circuit test and PSPICE macromodel simulation.
文摘This paper presents a novel inter-cluster direct current(DC)capacitor voltage balancing control scheme for the single-star configured modular multilevel cascaded converter(MMCC)-based static synchronous compensator(STATCOM)under unbalanced grid voltage.The negative-sequence component of grid voltage at the point of common connection(PCC)causes unbalanced active power flow in the phase limbs of converter.This leads to the imbalance of DC voltages of the sub-module capacitors across the MMCC phases,and consequently,the malfunction of converter.The proposed solution is to inject both negative-sequence current(NSC)and zero-sequence voltage(ZSV)into the phase limbs of MMCC.A quantification factor Qf is used to achieve the sharing of inter-cluster active pow-er between the NSC and ZSV injection methods.Accurate determination of the quantification factor has been presented.In addition to maintaining the DC voltages of sub-module capacitor across the MMCC phases balanced,it also prevents the overcurrent and overvoltage of converter by injecting NSC and ZSV with the right proportion.The control scheme is validated on a 3.54 kV 1.2 MVA power system using MMCC-based STATCOM with 3-level bridge cells as sub-modules.The results show that the proposed scheme provides superior effectiveness in eliminating the voltage imbalance of DC capacitor in the phase limb while maintaining low voltage and current ratings.
文摘文中提出一种新型单级式隔离型模块化多电平级联变换器(isolated modular multilevel cascade converter,I-MMCC),其具有中压三相交流(medium voltage three-phase AC,MVAC_((T-P)))、中压单相交流(medium voltage single phase AC,MVAC_((S-P)))和低压直流(low voltage DC,LVDC)3种电压端口。该变换器可实现从LVDC到MVAC的单级式功率变换,MVAC_((T-P))与MVAC_((S-P))电压端口能够实现同频或变频的AC-AC功率自由变换,其单极性调制策略可避免隔离型AC-AC矩阵变换器双向开关管换流暂态过程中出现的电压尖峰等问题。首先,介绍I-MMCC子模块拓扑结构与调制策略,并建立子模块及单相I-MMCC平均等效数学模型;其次,分析MVAC_((T-P))与MVAC_((S-P))端口变频–变压工作原理、稳态功率与端口特性,对单相交流端口基于正交虚拟电路概念,建立控制模型,并推导出MVAC_((S-P))、MVAC_((T-P))端口功率约束关系。最后,通过搭建一套实验样机验证所提出拓扑结构的有效性和优越性。
