In the DC microgrid,the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power.To ...In the DC microgrid,the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power.To address this issue,the application of a virtual synchronous generator(VSG)in grid-connected inverters control is referenced and proposes a control strategy called the analogous virtual synchronous generator(AVSG)control strategy for the interface DC/DC converter of the battery in the microgrid.Besides,a flexible parameter adaptive control method is introduced to further enhance the inertial behavior of the AVSG control.Firstly,a theoretical analysis is conducted on the various components of the DC microgrid,the structure of analogous virtual synchronous generator,and the control structure’s main parameters related to the DC microgrid’s inertial behavior.Secondly,the voltage change rate tracking coefficient is introduced to adjust the change of the virtual capacitance and damping coefficient flexibility,which further strengthens the inertia trend of the DC microgrid.Additionally,a small-signal modeling approach is used to analyze the approximate range of the AVSG’s main parameters ensuring system stability.Finally,conduct a simulation analysis by building the model of the DC microgrid system with photovoltaic(PV)and battery energy storage(BES)in MATLAB/Simulink.Simulation results from different scenarios have verified that the AVSG control introduces fixed inertia and damping into the droop control of the battery,resulting in a certain level of inertia enhancement.Furthermore,the additional adaptive control strategy built upon the AVSG control provides better and flexible inertial support for the DC microgrid,further enhances the stability of the DC bus voltage,and has a more positive impact on the battery performance.展开更多
To improve the vehicle dynamic performance and ultra-capacitor operating circumstance,this paper studied the multi-current-two-quadrant converter applied to drive high power DC motor in ultra-capacitor electric bus(UC...To improve the vehicle dynamic performance and ultra-capacitor operating circumstance,this paper studied the multi-current-two-quadrant converter applied to drive high power DC motor in ultra-capacitor electric bus(UCEB).Compared with normal current-two-quadrant converter,the multi-current-two-quadrant converter can reduce the motor armature current ripple and the ultra-capacitor current ripple.Moreover,it improves power capabilities,reliability and fault tolerant capability of driving system.After analyzing the structure and working principle of the multi-current-two-quadrant converter,the expressions of armature current ripple and the quantitative relationships between the ultra-capacitor power loss and duty cycle were derived.The simulation and experimental results showed that the multi-current-two-quadrant converter has great advantages in reducing the armature current ripple and ultra-capacitor power loss,which can improve the vehicle performance and overall efficiency.展开更多
As new technologies emerge data centers and servers have established themselves as one of the largest and fastest growing consumers of power.While switched capacitor converter topologies have some very attractive feat...As new technologies emerge data centers and servers have established themselves as one of the largest and fastest growing consumers of power.While switched capacitor converter topologies have some very attractive features,namely low reliance on magnetic components and high efficiency,several critical factors have prevented their adoption in high current data center applications.The family of converters proposed are novel intermediate bus converter that demonstrates the highest performance yet achieved for 48 V to 12 V conversion with up to 2.5 kW/in^(3) power density,higher than 99% peak efficiency,and 97.2% full load efficiency for 12 V/70 A output.The reduction of voltage stress across the MOSFETs as well as extremely low reliance on magnetics are the key driving factors behind this high efficiency and power density,and are achieved without a sensitive resonant design or the usage of complex control technique.展开更多
This paper discusses the chief techniques and design principles of an ultra-high speed and dual-channel data acquisition card based on PXI bus, using FPGA (Field Programmable Gate Array) as logic controller cell. The ...This paper discusses the chief techniques and design principles of an ultra-high speed and dual-channel data acquisition card based on PXI bus, using FPGA (Field Programmable Gate Array) as logic controller cell. The instmment consists of pre-pro- cess circuit, A/D converter, SDRAM (Synchronous Dynamic random access memory), and control circuit integrated in FPGA. It can achieve allowing up to 1000MHz real-time sampling rate. The test result indicates that the system works normally and the system design is successful.展开更多
Bidirectional interlinking converter(BIC)is the core equipment in a hybrid AC/DC microgrid connected between AC and DC sub-grids.However,the variety of control modes and flexible bidirectional power flow complicate th...Bidirectional interlinking converter(BIC)is the core equipment in a hybrid AC/DC microgrid connected between AC and DC sub-grids.However,the variety of control modes and flexible bidirectional power flow complicate the influence of AC faults on BIC itself and on DC sub-grid,which potentially threaten both converter safety and system reliability.This study first investigates AC fault influence on the BIC and DC bus voltage under different BIC control modes and different pre-fault operation states,by developing a mathematical model and equivalent sequence network.Second,based on the analysis results,a general accommodative current limiting strategy is proposed for BIC without limitations to specific mode or operation condition.Current amplitude is predicted and constrained according to the critical requirements to protect the BIC and relieving the AC fault influence on the DC bus voltage.Compared with conventional methods,potential current limit failure and distortions under asymmetric faults can also be avoided.Finally,experiments verify feasibility of the proposed method.展开更多
基金funded by the National Natural Science Foundation of China(52067013),and the Provincial Natural Science Foundation of Gansu(20JR5RA395).
文摘In the DC microgrid,the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power.To address this issue,the application of a virtual synchronous generator(VSG)in grid-connected inverters control is referenced and proposes a control strategy called the analogous virtual synchronous generator(AVSG)control strategy for the interface DC/DC converter of the battery in the microgrid.Besides,a flexible parameter adaptive control method is introduced to further enhance the inertial behavior of the AVSG control.Firstly,a theoretical analysis is conducted on the various components of the DC microgrid,the structure of analogous virtual synchronous generator,and the control structure’s main parameters related to the DC microgrid’s inertial behavior.Secondly,the voltage change rate tracking coefficient is introduced to adjust the change of the virtual capacitance and damping coefficient flexibility,which further strengthens the inertia trend of the DC microgrid.Additionally,a small-signal modeling approach is used to analyze the approximate range of the AVSG’s main parameters ensuring system stability.Finally,conduct a simulation analysis by building the model of the DC microgrid system with photovoltaic(PV)and battery energy storage(BES)in MATLAB/Simulink.Simulation results from different scenarios have verified that the AVSG control introduces fixed inertia and damping into the droop control of the battery,resulting in a certain level of inertia enhancement.Furthermore,the additional adaptive control strategy built upon the AVSG control provides better and flexible inertial support for the DC microgrid,further enhances the stability of the DC bus voltage,and has a more positive impact on the battery performance.
基金Sponsored by the Heilongjiang 11th Five-year Key Project of Scientific and Technological(Grant No.GA06A305)
文摘To improve the vehicle dynamic performance and ultra-capacitor operating circumstance,this paper studied the multi-current-two-quadrant converter applied to drive high power DC motor in ultra-capacitor electric bus(UCEB).Compared with normal current-two-quadrant converter,the multi-current-two-quadrant converter can reduce the motor armature current ripple and the ultra-capacitor current ripple.Moreover,it improves power capabilities,reliability and fault tolerant capability of driving system.After analyzing the structure and working principle of the multi-current-two-quadrant converter,the expressions of armature current ripple and the quantitative relationships between the ultra-capacitor power loss and duty cycle were derived.The simulation and experimental results showed that the multi-current-two-quadrant converter has great advantages in reducing the armature current ripple and ultra-capacitor power loss,which can improve the vehicle performance and overall efficiency.
文摘As new technologies emerge data centers and servers have established themselves as one of the largest and fastest growing consumers of power.While switched capacitor converter topologies have some very attractive features,namely low reliance on magnetic components and high efficiency,several critical factors have prevented their adoption in high current data center applications.The family of converters proposed are novel intermediate bus converter that demonstrates the highest performance yet achieved for 48 V to 12 V conversion with up to 2.5 kW/in^(3) power density,higher than 99% peak efficiency,and 97.2% full load efficiency for 12 V/70 A output.The reduction of voltage stress across the MOSFETs as well as extremely low reliance on magnetics are the key driving factors behind this high efficiency and power density,and are achieved without a sensitive resonant design or the usage of complex control technique.
文摘This paper discusses the chief techniques and design principles of an ultra-high speed and dual-channel data acquisition card based on PXI bus, using FPGA (Field Programmable Gate Array) as logic controller cell. The instmment consists of pre-pro- cess circuit, A/D converter, SDRAM (Synchronous Dynamic random access memory), and control circuit integrated in FPGA. It can achieve allowing up to 1000MHz real-time sampling rate. The test result indicates that the system works normally and the system design is successful.
文摘Bidirectional interlinking converter(BIC)is the core equipment in a hybrid AC/DC microgrid connected between AC and DC sub-grids.However,the variety of control modes and flexible bidirectional power flow complicate the influence of AC faults on BIC itself and on DC sub-grid,which potentially threaten both converter safety and system reliability.This study first investigates AC fault influence on the BIC and DC bus voltage under different BIC control modes and different pre-fault operation states,by developing a mathematical model and equivalent sequence network.Second,based on the analysis results,a general accommodative current limiting strategy is proposed for BIC without limitations to specific mode or operation condition.Current amplitude is predicted and constrained according to the critical requirements to protect the BIC and relieving the AC fault influence on the DC bus voltage.Compared with conventional methods,potential current limit failure and distortions under asymmetric faults can also be avoided.Finally,experiments verify feasibility of the proposed method.
