Current source inverter(CSI)is a class of power electronic converters that,thanks to the inherent boost capability and ease of control,is investigated for grid-tied photovoltaic power conversion applications.Tradition...Current source inverter(CSI)is a class of power electronic converters that,thanks to the inherent boost capability and ease of control,is investigated for grid-tied photovoltaic power conversion applications.Traditional CSI and CSI7 topologies are here analyzed and compared with two kind of space vector modulation strategies mainly in terms of ground leakage current both in simulations and experiments.Furthermore,THD of the injected grid current and the computation of conduction and switching semiconductor power losses are also carried out in numerical simulations.The topology comparison is carried out with the use of a different number of PV modules,to analyze the robustness of the topologies to different size of the PV strings.Simulation and experimental results show that the CSI7 topology,with respect to conventional CSI,allows to strongly reduce ground leakage current,phase current THD and semicondutor power losses,at the price of an additional power device.展开更多
A generalized single-phase multilevel current source inverter (MCSI) topology with self-balancing current is proposed, which uses the duality transformation from the generalized multilevel voltage source inverter (MVS...A generalized single-phase multilevel current source inverter (MCSI) topology with self-balancing current is proposed, which uses the duality transformation from the generalized multilevel voltage source inverter (MVSI) topology. The existing single-phase 8-and 6-switch 5-level current source inverters (CSIs) can be derived from this generalized MCSI topology. In the proposed topology, each intermediate DC-link current level can be balanced automatically without adding any external circuits; thus, a true multilevel structure is provided. Moreover, owing to the dual relationship, many research results relating to the op- eration, modulation, and control strategies of MVSIs can be applied directly to the MCSIs. Some simulation results are presented to verify the proposed MCSI topology.展开更多
The paper proposes a Current Source Multilevel Inverter (CSMLI) with single rating inductor topology. Multilevel inverters are most familiar with power converter’s applications due to reduced dv/dt, di/dt stress, and...The paper proposes a Current Source Multilevel Inverter (CSMLI) with single rating inductor topology. Multilevel inverters are most familiar with power converter’s applications due to reduced dv/dt, di/dt stress, and very efficient for reducing harmonic distortion in the output voltage and output current. The proposed nine-level current source inverter has been tested under symmetrical and asymmetrical modes of operation, and their activities are compared using PI and Fuzzy PI (Proportional Integral) controllers with multicarrier PWM (Pulse Width Modulation) strategy. MATLAB/Simulink simulation has been made for the proposed converter to obtain its performance measures. Some experimental results are given to verify the presented Current Source Multilevel Inverter.展开更多
Nonlinear loads in the power distribution system cause non-sinusoidal currents and voltages with harmonic components.Shunt active filters(SAF) with current controlled voltage source inverters(CCVSI) are usually used t...Nonlinear loads in the power distribution system cause non-sinusoidal currents and voltages with harmonic components.Shunt active filters(SAF) with current controlled voltage source inverters(CCVSI) are usually used to obtain balanced and sinusoidal source currents by injecting compensation currents.However,CCVSI with traditional controllers have a limited transient and steady state performance.In this paper,we propose an adaptive dynamic programming(ADP) controller with online learning capability to improve transient response and harmonics.The proposed controller works alongside existing proportional integral(PI) controllers to efficiently track the reference currents in the d-q domain.It can generate adaptive control actions to compensate the PI controller.The proposed system was simulated under different nonlinear(three-phase full wave rectifier) load conditions.The performance of the proposed approach was compared with the traditional approach.We have also included the simulation results without connecting the traditional PI control based power inverter for reference comparison.The online learning based ADP controller not only reduced average total harmonic distortion by 18.41%,but also outperformed traditional PI controllers during transients.展开更多
This project proposes a novel dual-input matrix converter (DIMC) which is used to integrate the output of the wind energy to a power grid. The proposed matrix converter is developed based on the traditional indirect m...This project proposes a novel dual-input matrix converter (DIMC) which is used to integrate the output of the wind energy to a power grid. The proposed matrix converter is developed based on the traditional indirect matrix converter under reverse power flow operation mode, but with its six-switch voltage source converter replaced by a nine-switch configuration followed by the current source inverter (CSI). Matrix electric power conversion topologies and their switch functions are flexible and are used for specific applications. With the additional three switches, the proposed DIMC can provide six input terminals, which make it possible to integrate two independent AC sources from two independent wind turbines into a single grid tied power electronics interface. Commanded currents can be extracted from the two input sources to the grid. The proposed PI control and modulation schemes guaranteed sinusoidal input and output waveforms as well as reduced THD. The simulation results are provided to validate the effectiveness of the proposed control and modulation schemes for the proposed converter.展开更多
The fast switching behaviors of wide bandgap devices bring some challenges such as high du/dt and limited short-circuit current withstand capability to the reliable operation of the motor drives.The current-source-inv...The fast switching behaviors of wide bandgap devices bring some challenges such as high du/dt and limited short-circuit current withstand capability to the reliable operation of the motor drives.The current-source-inverter(CSI)provides a promising solution in mitigating those challenges by owning the DC-link choke,the reverse-voltage blocking switches and AC commutation capacitors.To further reduce du/dt on switches of CSI fed motor drives,the technique of partial charging of capacitors have been investigated in this paper.By designing the series-connected and the parallel-connected partial-charging circuit for capacitors in DC-link,the voltage profile of CSI could be improved.Specifically,the zero-voltage-switching(ZVS)is achieved for main power switches,the du/dt is reduced and the overvoltage protection is presented.The working mechanism of the technique of partial charging of capacitor is described and one example is discussed on the dual three-phase motor drive.The experimental verification is presented to show the performance of partial charging technique for improving voltage profile of CSI fed motor drives.展开更多
基金Supported by the Ningbo Science&Technology Beauro(2017D10031,2018A-08-C)(3315 Innovation Team).
文摘Current source inverter(CSI)is a class of power electronic converters that,thanks to the inherent boost capability and ease of control,is investigated for grid-tied photovoltaic power conversion applications.Traditional CSI and CSI7 topologies are here analyzed and compared with two kind of space vector modulation strategies mainly in terms of ground leakage current both in simulations and experiments.Furthermore,THD of the injected grid current and the computation of conduction and switching semiconductor power losses are also carried out in numerical simulations.The topology comparison is carried out with the use of a different number of PV modules,to analyze the robustness of the topologies to different size of the PV strings.Simulation and experimental results show that the CSI7 topology,with respect to conventional CSI,allows to strongly reduce ground leakage current,phase current THD and semicondutor power losses,at the price of an additional power device.
文摘A generalized single-phase multilevel current source inverter (MCSI) topology with self-balancing current is proposed, which uses the duality transformation from the generalized multilevel voltage source inverter (MVSI) topology. The existing single-phase 8-and 6-switch 5-level current source inverters (CSIs) can be derived from this generalized MCSI topology. In the proposed topology, each intermediate DC-link current level can be balanced automatically without adding any external circuits; thus, a true multilevel structure is provided. Moreover, owing to the dual relationship, many research results relating to the op- eration, modulation, and control strategies of MVSIs can be applied directly to the MCSIs. Some simulation results are presented to verify the proposed MCSI topology.
文摘The paper proposes a Current Source Multilevel Inverter (CSMLI) with single rating inductor topology. Multilevel inverters are most familiar with power converter’s applications due to reduced dv/dt, di/dt stress, and very efficient for reducing harmonic distortion in the output voltage and output current. The proposed nine-level current source inverter has been tested under symmetrical and asymmetrical modes of operation, and their activities are compared using PI and Fuzzy PI (Proportional Integral) controllers with multicarrier PWM (Pulse Width Modulation) strategy. MATLAB/Simulink simulation has been made for the proposed converter to obtain its performance measures. Some experimental results are given to verify the presented Current Source Multilevel Inverter.
文摘Nonlinear loads in the power distribution system cause non-sinusoidal currents and voltages with harmonic components.Shunt active filters(SAF) with current controlled voltage source inverters(CCVSI) are usually used to obtain balanced and sinusoidal source currents by injecting compensation currents.However,CCVSI with traditional controllers have a limited transient and steady state performance.In this paper,we propose an adaptive dynamic programming(ADP) controller with online learning capability to improve transient response and harmonics.The proposed controller works alongside existing proportional integral(PI) controllers to efficiently track the reference currents in the d-q domain.It can generate adaptive control actions to compensate the PI controller.The proposed system was simulated under different nonlinear(three-phase full wave rectifier) load conditions.The performance of the proposed approach was compared with the traditional approach.We have also included the simulation results without connecting the traditional PI control based power inverter for reference comparison.The online learning based ADP controller not only reduced average total harmonic distortion by 18.41%,but also outperformed traditional PI controllers during transients.
文摘This project proposes a novel dual-input matrix converter (DIMC) which is used to integrate the output of the wind energy to a power grid. The proposed matrix converter is developed based on the traditional indirect matrix converter under reverse power flow operation mode, but with its six-switch voltage source converter replaced by a nine-switch configuration followed by the current source inverter (CSI). Matrix electric power conversion topologies and their switch functions are flexible and are used for specific applications. With the additional three switches, the proposed DIMC can provide six input terminals, which make it possible to integrate two independent AC sources from two independent wind turbines into a single grid tied power electronics interface. Commanded currents can be extracted from the two input sources to the grid. The proposed PI control and modulation schemes guaranteed sinusoidal input and output waveforms as well as reduced THD. The simulation results are provided to validate the effectiveness of the proposed control and modulation schemes for the proposed converter.
基金Supported by the Jiangsu Natural Science Foundation of China(BK20180013)in part by Shen Zhen Science and Technology Project(CYJ20180306174439784).
文摘The fast switching behaviors of wide bandgap devices bring some challenges such as high du/dt and limited short-circuit current withstand capability to the reliable operation of the motor drives.The current-source-inverter(CSI)provides a promising solution in mitigating those challenges by owning the DC-link choke,the reverse-voltage blocking switches and AC commutation capacitors.To further reduce du/dt on switches of CSI fed motor drives,the technique of partial charging of capacitors have been investigated in this paper.By designing the series-connected and the parallel-connected partial-charging circuit for capacitors in DC-link,the voltage profile of CSI could be improved.Specifically,the zero-voltage-switching(ZVS)is achieved for main power switches,the du/dt is reduced and the overvoltage protection is presented.The working mechanism of the technique of partial charging of capacitor is described and one example is discussed on the dual three-phase motor drive.The experimental verification is presented to show the performance of partial charging technique for improving voltage profile of CSI fed motor drives.
