High Linear Voltage Gain in QZNC Through Synchronizing Switching Circuits

The solar powered systems require high step-up converter for efficient energy transfer.For this,quasi-impedance network converter has been introduced.The quasi-impedance network converter(QZNC)is of two types:type-1 and type-2 configuration.Both the type-1 and type-2 QZNC configurations have drooping voltage gain profile due to presence of high switching noise.To overcome this,a new quasi-impedance network converter synchronizing the switching circuit with low frequency noise has been proposed.In this paper,the proposed QZNC con-figuration utilizes the current controlling diode to prevent the output voltage drop.Thus,the suggested topology provides linear high voltage gain profile,low load voltage ripple,and reduced impedance network stress and device stress.There-fore,the efficiency of proposed QZNC has been improved.The topology descrip-tion,working principle,parameter design and comparison with traditional converters are illustrated.Andfinally,both simulation and practical results are presented to confirm the converter characteristics and performance.From the results,it has been found that the performance of the suggested topology is better as it achieves a higher efficiency of 81%and hence,it is suitable for high power applications.

Output Voltage Ripple (OVR) Reduction of Boost Converter Using Particle Swarm Optimization

KY Boost Converter, a modern invention in the field of non-isolated DC-DC boost converter is identified for minimum voltage ripple. KY boost converter is the com- bination of KY converter and traditional boost converter. Such a converter has con- tinuous input and output inductor current, different from the traditional boost con- verter. And hence this converter is very suitable for very low-ripple applications. The Particle Swarm Optimization (PSO) based controller, FUZZY based controller and open loop KY boost converter are designed in MATLAB/Simulink model. The simu- lated results show a reduction in output ripple from 1.18 V of the existing open loop KY boost converter output to 0.54 V in the FUZZY logic controlled converter out- put. Further reduction in output ripple to 0.29 V is achieved in the proposed PSO based converter. The simulated results also show the variation of switching pulses based on the different existing and proposed method.

Fuzzy Based Interleaved Step-up Converter for Electric Vehicle

This work focuses on the fuzzy controller for the proposed three-phase interleaved Step-up converter(ISC).The fuzzy controller for the proposed ISC converters for electric vehicles has been discussed in detail.The proposed ISC direct current(DC-DC)converter could also be used in automobiles,satellites,industries,and propulsion.To enhance voltage gain,the proposed ISC Converter combines boost converter and interleaved converter(IC).This design also reduces the number of switches.As a result,ISC converter switching losses are reduced.The proposed ISC Converter topology can produce a 143 V output voltage and 1 kW of power.Due to the high voltage gain of this converter design,it is suitable for medium and high-power systems.The proposed ISC Converter topology is simulated in MATLAB/Simulink.The simulated output displays a high output voltage.But the output voltage contains maximum ripples.Fuzzy proposes an ISC Converter which makes closed loop responsiveness and reduces the output voltage ripple.The proposed ISC converter has the lowest ripple output voltage,which is less than 2%,because the duty cycle is regulated using the fuzzy logic controller.It offers high voltage gain,minimal ripple,and low switching loss.The performance of the proposed converter is compared to that of the fuzzy and Pro-portional Integral(PI)controllers implemented in MATLAB.

Modeling and Analysis of Pulse Skip Modulation

The state space average model and the large signal models of Pulse Skip Modulation （PSM） mode are given in this paper. Farther more, based on these models and simulations of PSM converter circuits, the analysis of the characteristics of PSM converter is described in this paper, of which include efficiency, frequency spectrum analysis, output voltage ripple, response speed and interference rejection capability. Compared with PWM control mode, PSM converter has high efficiency, especially with fight loads, quick response, good interference rejection and good EMC characteristic. Improved PSM slightly, it could be a kind of good independent regulating mode during the whole operating process for a DC-DC converter. Finally, some experimental results are also presented in this paper.

Improved Dynamic Response of DC to DC Converter Using Hybrid PSO Tuned Fuzzy Sliding Mode Controller

DC/DC switching converters are widely used in numerous appliances in modern existence. In this paper, the dynamic and transient response of phase shift series resonant DC/DC converter are improved using hybrid particle swarm optimization tuned fuzzy sliding mode controller under starting and load step change conditions. The aim of the control is to regulate the output voltage beneath the load change. The model of the hybrid particle swarm optimization tuned fuzzy sliding mode controller is implemented using Sim Power Systems toolbox of MATLAB SIMULINK. Performance of the proposed dynamic novel control under step load change condition is investigated.

Evaluation Method of Output Waveform Quality for Neutral⁃Point⁃ Clamped Three⁃Level Converter

An analytical evaluation method for output waveform quality of space vector pulse width modulation(PWM)strategies applied in neutral⁃point⁃clamped three⁃level converter(3L⁃NPC)is proposed in this paper.Low frequency error caused by neutral point voltage ripple and high frequency error introduced by space vector synthesis were both taken into account,and the unified error model of output current ripple was established.By taking continuous and discontinuous modulation strategies as examples,the unified error model was validated through Fourier analysis of the experimental results.The proposed evaluation method will be helpful for the switching sequence optimization and the modulation strategy selection.

Design of High Efficiency DC-DC Converter for Photovoltaic Solar Home Applications

The solar energy conversion system is very interesting alternative on supplement the electric system generation, due to the persistent cost reduction of the overall system and cleaner power generation. To obtain a stable voltage from an input supply （PV cells） that is higher and lower than the output, a high efficiency and minimum ripple DC-DC converter required in the system for residential power production. Buck-boost converters make it possible to efficiently convert a DC voltage to either a lower or higher voltages. Buck-boost converters are especially useful for PV maximum power tracking purposes, where the objective is to draw maximum possible power from solar panels at all times, regardless of the load. This paper analyzes and describes step by step the process of designing, and simulation of high efficiency low ripple voltage buck-boost DC-DC converter for the photovoltaic solar conversion system applicable to a （typical） single family home based on battery-based systems. The input voltage can typically change from （20 V） initially, down to （5 V）, and provide a regulated voltage within the range of the battery （12 V）. PLECS simulation results provide strong evidences about the high efficiency, minimum ripple voltage, high accuracy, and the usefulness of the system of the proposed converter when applied to either residential or solar home applications.

A high stability high voltage power supply design for HEPS injection system

Purpose The high energy photon source(HEPS)uses the on-axial injection scheme.There are two designs in this injection scheme that are critical to the performance of the HEPS injection system.One is the strip line kicker and another is the high voltage fast pulse power supply system.In the high voltage fast pulse power supply system,the design of high voltage power supply is very important.The output voltage stability of high voltage power supply directly affects the stability of the pulse amplitude of the injection system.Methods A high voltage power supply with high output voltage stability is designed in this paper,and the scheme is given.The correctness of the design scheme is verified by simulation experiments.Result A prototype is built for full test.The test results showed that the output voltage stability is lower than 58 ppm.The output voltage is 6.4 mV(f≤3 kHz)/113.2 mV(f>3 kHz).Conclusions The designed high voltage power supply can fully meet the requirements of the HEPS injection system.

Modular Multilevel Converter with Thyristor DC-link Switch for Full-torque Variable-speed Drives

The modular multilevel converter(MMC)is a promising topology for medium-voltage drive applications due to its high-quality output waveforms,low device switching frequency and voltage rating.However,the large cell capacitor voltage ripple is a severe challenge faced by MMC at low motor speeds.Recently,a hybrid MMC(HMMC)topology is proven to be a competitive solution because of its lower cell capacitor voltage ripple and not demonstrating a common-mode voltage(CMV)problem compared with other methods.However,the DC-link switch with IGBT limits HMMC from being applied in highvoltage applications.This paper uses a thyristor instead of IGBT as the DC-link switch.To ensure the thyristor can be softly turned on and safely turned off,a new control scheme is proposed.When using this proposed scheme,HMMC can also tolerate the failure of the thyristor being turned-off without shutting down the system,effectively improving its reliability.The cell capacitor voltage ripple analysis is presented considering the effects of the thyristor switching process.In addition,a decoupled energy balancing control is utilized to suppress the fluctuation of the DC current.Experimental results obtained from a 380 V/7.5 kW downscaled prototype validate the effectiveness of starting up a motor from the standby mode to rated speed applying full-torque.

Research and design of a novel current mode charge pump

To meet the demands for a number of LEDs,a novel charge pump circuit with current mode control is proposed.Regulation is achieved by operating the current mirrors and the output current of the operational transconductance amplifier.In the steady state,the input current from power voltage retains constant,so reducing the noise induced on the input voltage source and improving the output voltage ripple.The charge pump small-signal model is used to describe the device’s dynamic behavior and stability.Analytical predictions were verified by Hspice simulation and testing.Load driving is up to 800 mA with a power voltage of 3.6 V,and the output voltage ripple is less than 45 mV.The output response time is less than 8μs,and the load current jumps from 400 to 800 mA.

Modular Multilevel Converter with Wireless Magnetic Power Decoupling for Three-phase MV Adjustable-speed Drives

In this paper,we propose a modular multilevel converter(MMC)with a wireless magnetic power decoupling approach suitable for medium-voltage high-power variable-speed machine drives.Our proposed power decoupling approach is independent of the operating frequency,which solves the issue of wide fluctuations of low-frequency voltage ripple components in submodule(SM)capacitors,especially at low-speed operations without using any ripple power capacitor.Employing wireless magnetic elements reduces the amount of high-voltage insulation between the transformer windings,resulting in a significant reduction in the overall size of the system.The basic idea of our proposed approach is to magnetically couple the instantaneous three-phase ripple power of each of the three adjacent-arm SMs.The proposed MMC is free from low-frequency capacitors,resulting in enhanced system reliability,volume,and lifetime.The operation principles of the proposed MMC are explained,and a control design is introduced.The performance of the proposed scheme was verified via simulation and experimental tests.

Development of corrector magnet power supply for high energy photon source

Purpose High Energy Photon Source(HEPS)requires high quality,high energy beam and ultra-low emittance of 0.1 nm·rad,which puts forward high demand for power supply.In this paper,a high-performance corrector magnet power supply is developed to calibrate and adjust beam track within a certain bandwidth range to ensure the stability of beam track.Methods The prototype of power supply adopts the new"One control Two"control mode,which adjusts the performance of two power supplies simultaneously based on digital control.Results The experimental results show that the stability of the power supply is lower than 20 ppm,which is far better than the design index.Voltage ripple is less than 10 mV,and other performance indexes meet the physical design requirements,which can well meet the requirements of HEPS construction.Conclusions After a lot of experiments and tests,all the parameters passed the design indicators.The successful development of this power supply has laid a foundation for the successful application of HEPS.

A dual mode charge pump with adaptive output used in a class G audio power amplifier

A dual mode charge pump to produce an adaptive power supply for a class G audio power amplifier is presented.According to the amplitude of the input signals,the charge pump has two level output voltage rails available to save power.It operates both in current mode at high output load and in pulse frequency modulation （PFM） at light load to reduce the power dissipation.Also,dynamic adjustment of the power stage transistor size based on load current at the PFM mode is introduced to reduce the output voltage ripple and prevent the switching frequency from audio range.The prototype is implemented in 0.18μm 3.3 V CMOS technology.Experimental results show that the maximum power efficiency of the charge pump is 79.5%@ 0.5x mode and 83.6%@ lx mode.The output voltage ripple is less than 15 mV while providing 120 mA of the load current at PFM control and less than 18 mV while providing 300 mA of the load current at current mode control.An analytical model for ripple voltage and efficiency calculation of the proposed PFM control demonstrates reasonable agreement with measured results.

Development of high-precision DC power supply prototype for HEPS-TF

Purpose This power supply prototype is developed for the quadrupole magnets in the storage ring of HEPS.The project requires a high current stability of these power supplies,in order to master the key technology of this type of power supply in advance,a prototype is made in the project of HEPS test facility.Methods Modularization is used in the prototype’s topology and a combination of digital and analog control is adopted in the closed-loop control.Three control loops are used to improve the output current’s quality.In order to improve the current stability,the key devices in the circuit are under thermostatical controlled.Results The acceptance test results for the NDRC are given in details,which show that all the parameters are better than the design indexes.Conclusions After a lot of experiments and tests,all the parameters of this prototype passed the acceptance test.Among the results,the stability of this prototype achieved 5.2 ppm,the repeatability is 3.2 ppm,and the low-frequency voltage ripples are lower than the requirements of Physicists.The success of this prototype means that the requirements of power supplies in physical design can be met.