Digitally assisted control techniques for high performance switching DC-DC converters

Digitally controlled switching DC-DC converters have recently emerged as an attractive alternative to conventional switching converters based on analog control techniques. This research focuses on eliminating the issues associated with the state of the art switching converters by proposing three novel control techniques: (1) a digitally controlled Buck-Boost converter uses a fully synthesized constant ON/OFF time-based fractional-N controller to regulate the output over a 3.3V-to-5.5V input voltage range and provides seamless transition from buck to buck-boost modes (2) a hysteretic buck converter that employs a highly digital hybrid voltage/current mode control to regulate output voltage and switching frequency independently (3) a 10MHz continuous time PID controller using time based signal processing which alleviates the speed limitations associated with conventional analog and digital. All the three techniques employ digitally assisted control techniques and require no external compensation thus making the controllers fully integrated and highly cost effective

Discussion of the technology and research in fuel injectors common rail system

Common rail is one of the most important components in a diesel and gasoline direct injection system. It features a high-pressure (100 bar) fuel rail feeding solenoid valves, as opposed to a low-pressure fuel pump feeding unit injectors. Third-generation common rail diesels now feature piezoelectric injectors for increased precision, with fuel pressures up to 2,500 bar. The purpose of this review paper is to investigate the technology and research in fuel injectors common rail system. This review paper focuses on component of common rail injection system, pioneer of common rail injection, characteristics of common rail injection system, method to reduce smoke and NOx emission simultaneously and impact of common rail injection system. Based on our research, it can be concluded that common rail injection gives many benefit such as good for the engine performance, safe to use, and for to reduce the emission of the vehicle. Fuel injection common rail system is the modern technology that must be developed. Nowadays, our earth is polluting by vehicle output such as smoke. If the common rail system is developed, it can reduce the pollution and keep our atmosphere clean and safe

Comparative Analysis of Different Control Schemes for DC-DC Converter: a Review

DC-DC converters are some power electronic circuits that convert the DC voltage from one level to another. They have a very large area of applications ranging from computing to communication. They are widely used in appliance control transportations and high-power transmission. Its increasing demand is based on its capability of electrical energy conversion. The basic topologies of DC-DC converter are Buck converter and Boost converter, other topologies are derived from these two basic topologies. Mathematical modelling of both Buck converters is done. Some of the control schemes are summarized in this paper. Current mode control (CMC), PID, Sliding Mode (SM) control including their advantages and disadvantages are highlighted in this paper

Razvoj robusnog diskretnog regulatora za silazni pretvarač s dvostrukom frekvencijom preklapanja

A discrete controller is designed for high efficiency double frequency buck converter. This double frequency buck converter is comprised of two buck cells: one works at high frequency, and another works at low frequency. It operates in a way that current in the high frequency switch is diverted through the low frequency switch. Thus, the converter can operate at very high frequency without adding any additional control circuits. Moreover, the switching loss of the converter remains small. The proposed converter exhibits improved steady -- state and transient response with low switching loss. A digital compensator further improves the dynamic performance of the closed loop system. Simulation of digitally controlled double frequency buck converter is performed with MATLAB / Simulink. Experimental results are given to demonstrate the effectiveness of the controller using LabVIEW with a Data Acquisition Card (NI - 9221).Dikretni regulator je projektiran za postizanje visoke efikasnosti silaznog pretvarača s dvostrukom frekvencijom preklapanja. Ovaj silazni pretvarač s dvostrukom frekvencijom preklapanja sastoji se od dvaju ćelija: po jedna za rad na visokim i niskim frekvencijama preklapanja. Regulator funkionira tako da se struja preklapanja na visokim frekvencijama preusmjerava kroz prekidač za preklapanje na niskim frekvencijama. Tako pretvarač može funkcionirati na vrlo visokim frekvencijama bez dodatnih upravljačkih krugova. štoviše, gubici prekidanja pretvarača ostaju mali. Prikazani pretvarač pokazuje poboljšanja kod odzivu u ustaljenom stanju te u prijelaznim pojavama uz male gubitke prilikom prekidanja. Digitalni kompenzator nadalje poboljšava dinamičke performanse sustava u zatvorenom krugu. Simulacije digitalno upravljanog silaznog pretvarača s dvostrukom frekvencijom preklapanja su provedene korištenjem MATLAB / Simulink-a. Eksperimentalni rezultati su prikazani kako bi se demonstrirala efikasnost regulatora korištenjem LabVIEW-a i kartice za prikupljanje podataka (NI - 9221)

DIGITAL CONTROL OF SWITCHING POWER CONVERTERS

This report describes the design of a digital controller that capable to control the switching action of Buck converter. It focuses on how to generate the DPWM signal in order to vary the ON/OFF condition of the low powerBuck converter switch. The main objective of this project is to have a controller that capable to produce a stable and high resolution of output voltage with high switching frequency response. Two (2) types of computer simulation have been carried out in this project which are the PSpice and MATLAB simulation. The PSpice simulation has been used to verify that the calculated parameters confirm the Buck converter operating in continuous conduction mode. The simulation results obtained in the PSpice simulation have been verified that the calculated parameters such resistor, inductor and capacitor value can be used for Buck converter circuit operating in continuous conduction mode. All the results obtained, except for the output current ripple are within ±10 % acceptable limit of percentage differences with its design requirements. The MATLAB simulation has been used to design the Buck converter system together with its digital controller part. The simulation results in MATLAB do not achieve the desired objectives because of the problem in setting the PID compensator coefficient which leads to a few simulation errors

Comparative Analysis of Different Control Schemes for DC-DC Converter: A Review

DC-DC converters are some power electronic circuits that convert the DC voltage from one level to another. They have a very large area of applications ranging from computing to communication. They are widely used in appliance control transportations and high-power transmission. Its increasing demand is based on its capability of electrical energy conversion. The basic topologies of DC-DC converter are Buck converter and Boost converter, other topologies are derived from these two basic topologies. Mathematical modelling of both Buck converters is done. Some of the control schemes are summarized in this paper. Current mode control (CMC), PID, Sliding Mode (SM) control including their advantages and disadvantages are highlighted in this paper

Alternative fuel from vegetable oils and animal fats

This study investigated the properties of processing vegetable and animal fat to be used as alternative fuel. The vegetable oil processing industry comprises the abstraction and treating of oils and fats from vegetable sources. Vegetable oils and fats are principally used for human consumption but are also used in animal feed, for medicinal purposes, and certain technical applications. In contrast triglycerides, vegetable waxes lack glycerin in their structure. Although many plant parts may yield oil, in commercial practice, oil is extracted primarily from seeds, for many developing countries, the concept of employing vegetable oils as sources for diesel fuels can be attractive. Often the culture of the appropriate plant is well established, the oil extraction well developed, and handling and storage well defined. Yields per hectare of tropical crops such as palm and coconut oils far exceed the yields of vegetable oils in temperate zones. Also, the production of most tropical vegetable oils has positive energy. A rendering process is performed to remove excess fat from animal carcasses and then turned into oil. Thus, to obtain refined oil, there is process from crude palm oil that involves removal of the products of hydrolysis and oxidation or abstraction process of oil from the palm kernels. After refining, the oil may be split (fractionated) into liquid and solid phases by thermo-mechanical means such as controlled cooling, crystallization, and filtering, the later oil is competing successfully with the more expensive groundnut, corn, and sunflower oils