Design of Digital Linear Power Supply with Low Current Ripple

A linear power supply is a circuit architecture directly driven by AC. Multiple high-voltage LEDs (light-emitting diodes) are connected in series to withstand the input voltage. The LEDs are divided into multiple segments through a segment switching mechanism to adapt to the pulsating DC changes after bridge rectification. Due to imperfect switching between control signals, there may be signal overlap or misalignment, which reduces circuit performance and component lifespan. Firstly, signal overlap occurs when the next segment opens before the previous segment is about to close. This state causes overlapping intervals where two segments of current combine, resulting in a high combined current that can lead to significant power losses and generate heat, potentially reducing the lifespan of the components. Secondly, signal misalignment occurs when the next segment prepares to open after the previous segment has completely closed. In this state, there is a time gap with no current flow, resulting in reduced output power and exacerbating LED flickering. Both of these undesirable phenomena introduce ripple into the LED output current. In this paper, a digitalized design is proposed to precisely compensate for the timing between alternating signals, significantly reducing output current ripple. This approach helps enhance power supply performance, extend component lifespan, and reduce LED index flicker.

Reducing input/output current ripple for driving converter by multiple technology

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.

Finite Control Set Model Predictive Current Control of a Five-Phase PMSM with Virtual Voltage Vectors and Adaptive Control Set

This paper presents an improved finite control set model predictive current control(FCS-MPCC)of a five-phase permanent magnet synchronous motor(PMSM).First,to avoid including all the 32 voltage vectors provided by a two-level five-phase inverter into the control set,virtual voltage vectors are adopted.As the third current harmonics can be much reduced by virtual voltage vectors automatically,the harmonic items in the cost function of conventional FCS-MPCC are not considered.Furthermore,an adaptive control set is proposed based on voltage prediction.Best control set with proper voltage vector amplitude corresponding to different rotor speed can be achieved by this method.Consequently,current ripples can be largely reduced and the system performs much better.At last,simulations are established to verify the steady and transient performance of the proposed FCS-MPCC,and experiments based on a 2 kW five-phase motor are carried out.The results have validated the performance improvement of the proposed control strategy.

Dual Mode-Multiple Output SEPIC Converter Integrated with Passive Ripple Cancelling Circuit for Standalone PV Energy Harvesting System

This document addresses an exhaustive standalone Photovoltaic (PV) energy harvesting system considering two crucial issues: system efficiency and cost effectiveness. It contributes a compact resolution with a combined feature of Dual Mode-Multiple Output (DMMO) associated with input ripple reduction technique. Control strategy incorporates with aspect of Maximum Power Point Tracking (MPPT) and output voltage levels regulation. A theoretical analysis is conducted to evaluate the effect of ripple current on PV power. Proposed dual mode converter achieves efficiency of 98.36% and 97.76% respectively for mode-1 and mode-2 operation. However, simulation is performed applying MATLAB/SIMULINK tools to analyze the feasibility of the recommended system.

Electric Window Regulator Based on Intelligent Control

In order to effectively solve the problem of installation cost of automobile electric windows and the safety of passengers,the window regulator of the car must have an intelligent control function.For example,most automobile windows now have an anti-pinch function.In this paper,the model of dc brushed motor is analyzed,an intelligent control scheme for automotive power windows is proposed,and the relationship between current ripple and window travel,motor current,and extemal resistance are verified.In the hardware design,S9S 12G128 is the main control chip,and the motor current acquisition method is designed.In the software design,intelligent control methods such as current integration method,adaptive and self-learning algorithm,and intelligent speed regulation method are proposed to realize functions such as automatic w indow opening and closing,intelligent anti-pinch,and intelligent speed regulation.After many experiments,the results prove the feasibility of the above methods and the stability of the system.

Fast corrector power supply design for HEPS

Background High-energy photon source under construction is a fourth-generation synchrotronradiation light source with energy of 6 Gev and ultra-low emittance(lower than 0.1 nm rad).The ultra-low beam emittance requires high beam stability.Purpose In order to meet this requirement of low beam emittance,the fast close orbit correctionsystem is used to keep beam on the right orbit.The fast close orbit correction system need fast corrector power supply to drive the calibration magnet to complete track correction.So,a fastcorrector power supply prototype with high bandwidth and low current ripple to improve the performance of the fast close orbit correction system to prove the high beam stability had beendeveloped.Methods The prototype use a novel multilevel switch-mode structure to provide the dynamicrequirement.The prototype adopts FPGA for full-digital control and use high-speed ADC with temperature control.By using a precision sampling circuit(ADC+DCCT),the prototypeoutputs current ripple can meet the requirement.Results and conclusion The designed for HEPS meet the design requirement.Through test,the prototype has asmall signal bandwidth of 10 kHz and output current ripple lower than 20 ppm.

A new active power filter topology based on a chopper circuit

Active power filters （APFs） are widely used for their outstanding performance in current and voltage rip- ple compensation. As modern high-energy accelerators are demanding much more stringent current ripple guidelines, APFs are used in the magnet power supply （MPS） in accelerator systems. However, conventional APFs have many drawbacks due to the traditional topology, such as complex structure, nonadjustable working voltage, requirement of power supply, and so on. This paper proposes a new APF topology, which works as two types of chopper circuits. This APF does not need extra electricity, but uses the power of the MPS current ripple to realize ripple depression. Experimental results prove its feasibility and effectiveness.