Positive Buck-boost Converter Research Articles

Dual input buck-boost converter for hybrid piezoelectric energy harvester – Supercapacitor sources

Integration of energy sources provides superior flexibility and reliability in low power electronic system. A dual input positive buck-boost converter is proposed for integrating piezoelectric energy harvester (PEH) and supercapacitor sources. The converter circuit consists of three active power switches, a common inductor, and an output filter capacitor. The active switch connected with the PEH is operated at the optimum duty cycle for maximum power extraction through impedance matching. The voltage at the output can be regulated by adjusting the duty ratio of the active switch connected with the supercapacitor. The charging mechanism of supercapacitor from a piezoelectric energy harvester is also presented. The operational performance of the proposed system is verified through simulation and validated by experimental investigation. The output power is measured for the range of load resistance, and a maximum power of 4.48 mW with the efficiency of 59% is obtained for the load resistance of 22 kΩ.

Efficient Performance Technical Selection of Positive Buck-Boost Converter

The necessity for stable DC voltage in both removable and non-removable systems has been considerably desired recently. These systems have to be implemented efficiently in order to be responding rapidly based voltage variations. Under this act, the efficient power can extend the lifetime of the employed batteries in such systems. The presented efficiency can be realized with respect to buck and boost components that were implemented to generate what is called positive Buck-Boost converter circuits. The main functions of the positive Buck-Boost converter are identified by announcing the unchanged situation of output voltage polarity and indicating the level of the voltage rationally between the input and the output. It is worth mention, the positive Buck-Boost converter circuit was simulated based Proteus software, and the hardware components were connected in reality. Finally, the microcontroller type that employed in the proposed system is PIC_16F877A, which realizes the input voltage sensitively to generate Pulse Width Modulation (PWM) signals in order to feed the employed MOSFET element.

DSP-BASED INTEGRATED CONTROL MODELING AND IMPLEMENTATION OF NONINVERTING BUCK-BOOST CONVERTER

The authors propose a new hybrid control system for digital implementation of a positive buck-boost DC-DC converter, based on DSP controller, high voltage regulating, and current integral loop controller for elimination of ripple inductor. This method is predicated on the theory of integrated dynamic system in which the inputs (Vin&Iin) and high loads of positive DC-DC converter is continuous and output as a discontinuous mode in lower loads. Therefore the system of the converter is accomplished by combination of two different characteristics of a dynamic modeling: a) Proper selection of the converter state variables, b) Average of inductor current and output errors that correspond to design and implementation of experimental system. Different load and input voltage variation conditions are simulated in MATLAB/SIMULINK and implemented in DSP controller and all of the results indicate the controller to verify the suitability designed controller. The simulation and experimental result on positive buck-boost DC-DC converter is found to be satisfactory.

A positive Buck-Boost voltage balancer for DC distribution system

This paper analyzes the load unbalance problem and voltage fluctuation problem in a 3-wire DC distribution system. It also analyzes a solution to these problems; a positive Buck-Boost voltage balancer is proposed and explored in order to fulfill the requirements of high quality power supply for the loads on its load side. Compared with the conventional balancer, a positive Buck-Boost converter is added to solve the voltage fluctuation problem, and the theories and methods of the voltage balancer are extended to analyze the working principle, derive the design equations, explore the stability, and calculate the efficiency. Both simulations and small power experiments are carried out to verify the validity of the working principle, the topology, and the control strategy.

Performance of Buck-Boost Converter with Mode Select Circuit and Feed Forward Technique

DC-DC converter topologies, the controllable switches are operated in switch mode where they are required to turn the entire load current on and off during each switching cycle. This work proposes a high- efficiency positive buck- boost converter with mode-select circuits and feed-forward techniques. Four power transistors produce more conduction and more switching losses when the positive and negative buck-boost converter operates in buck-boost mode. Utilizing the mode-select circuit, the proposed converter can decrease the loss of switches and let the positive buck-boost converter operate in buck, buck-boost, or boost mode. By adding feed-forward techniques, similarly for the proposed converter can improve transient response when the supply voltages are changed. The positive and negative feed forward technique of the buck boost converter is to be compared. The analysis and design method of the proposed work is carried out using MATLAB/ Simulink. PI controller is controlled using ABC algorithm. Index Terms: DC-DC converter, Positive output Buck-Boost converter, Proportional-Integral (PI) control.

The Effect of High Voltage, High Frequency Pulsed Electric Field on Slain Ovine Cortical Bone

High power, high frequency pulsed electric fields known as pulsed power (PP) has been applied recently in biology and medicine. However, little attention has been paid to investigate the application of pulse power in musculoskeletal system and its possible effect on functional behavior and biomechanical properties of bone tissue. This paper presents the first research investigating whether or not PP can be applied safely on bone tissue as a stimuli and what will be the possible effect of these signals on the characteristics of cortical bone by comparing the mechanical properties of this type of bone pre and post expose to PP and in comparison with the control samples. A positive buck-boost converter was applied to generate adjustable high voltage, high frequency pulses (up to 500 V and 10 kHz). The functional behavior of bone in response to pulse power excitation was elucidated by applying compressive loading until failure. The stiffness, failure stress (strength) and the total fracture energy (bone toughness) were determined as a measure of the main bone characteristics. Furthermore, an ultrasonic technique was applied to determine and comprise bone elasticity before and after pulse power stimulation. The elastic property of cortical bone samples appeared to remain unchanged following exposure to pulse power excitation for all three orthogonal directions obtained from ultrasonic technique and similarly from the compression test. Nevertheless, the compressive strength and toughness of bone samples were increased when they were exposed to 66 h of high power pulsed electromagnetic field compared to the control samples. As the toughness and the strength of the cortical bone tissue are directly associated with the quality and integrity of the collagen matrix whereas its stiffness is primarily related to bone mineral content these overall results may address that although, the pulse power stimulation can influence the arrangement or the quality of the collagen network causing the bone strength and toughness augmentation, it apparently did not affect the mineral phase of the cortical bone material. The results also confirmed that the indirect application of high power pulsed electric field at 500 V and 10 kHz through capacitive coupling method was safe and did not destroy the bone tissue construction.

A High-Efficiency Positive Buck–Boost Converter With Mode-Select Circuit and Feed-Forward Techniques

This paper presents a high-efficiency positive buck- boost converter with mode-select circuits and feed-forward techniques. Four power transistors produce more conduction and more switching losses when the positive buck-boost converter operates in buck-boost mode. Utilizing the mode-select circuit, the proposed converter can decrease the loss of switches and let the positive buck-boost converter operate in buck, buck-boost, or boost mode. By adding feed-forward techniques, the proposed converter can improve transient response when the supply voltages are changed. The proposed converter has been fabricated with TSMC 0.35-μm CMOS 2P4M processes. The total chip area is 2.59 × 2.74 mm2 (with PADs), the output voltage is 3.3 V, and the regulated supply voltage range is from 2.5-5 V. Its switching frequency is 500 kHz and the maximum power efficiency is 91.6% as the load current equals 150 mA.

A new family of marx generators based on commutation circuits

This paper presents a novel topology for the generation of high voltage pulses that uses both slow and fast solid-state power switches. This topology includes diode-capacitor units in parallel with commutation circuits connected to a positive buck-boost converter. This enables the generation of a range of high output voltages with a given number of capacitors. The advantages of this topology are the use of slow switches and a reduced number of diodes in comparison with conventional Marx generator. Simulations performed for single and repetitive pulse generation and experimental tests of a prototype hardware verify the proposed topology.

A Novel High-Voltage Pulsed-Power Supply Based on Low-Voltage Switch–Capacitor Units

This paper presents a high-voltage pulsed-power system based on low-voltage switch-capacitor units that are connected to a current source for several applications such as plasma systems. A modified positive buck-boost converter topology is used to utilize the current source concept, and a series of low-voltage switch-capacitor units is connected to the current source in order to provide a high voltage with a high voltage stress (dv/dt) as demanded by the loads. This pulsed-power converter is flexible in terms of energy control because the stored energy in the current source can be adjusted by changing the current magnitude to significantly improve the efficiency of various systems with different requirements. The output-voltage magnitude and stress (dv/dt) can be controlled by a proper selection of components and control algorithm to turn on and off the switching devices.

Digital Combination of Buck and Boost Converters to Control a Positive Buck–Boost Converter and Improve the Output Transients

A highly efficient and novel control strategy for improving the transients in the output voltage of a DC-DC positive buck-boost converter, required for low-power portable electronic applications, is presented in this paper. The proposed control technique can regulate the output voltage for variable input voltage, which is higher, lower, or equal to the output voltage. There are several existing solutions to these problems, and selecting the best approach involves a tradeoff among cost, efficiency, and output noise or ripple. In the proposed method, instead of instantaneous transition from buck to boost mode, intermediate combination modes consisting of several buck modes followed by several boost modes are utilized to distribute the voltage transients. This is unique of its kind from the point of view of improving the efficiency and ripple content in the output voltage. Theoretical considerations are presented. Simulation and experimental results are shown to prove the proposed theory.

Utilising Robustness of Positive Buck-Boost Converter Against Input Voltage and Load Current Disturbances

A positive buck-boost (PBB) converter is a known DC-DC converter that can operate in step-up and step-down modes. Unlike buck, boost and inverting buck-boost converters, the inductor current of a PBB can be controlled independently of its voltage conversion ratio. In other words, the inductor of PBB can be utilised as an energy storage unit in addition to its main function of energy transfer. In this paper, the capability of PBB to store energy has been utilised to achieve robustness against input voltage fluctuations and output current changes. The control strategy has been developed to keep accuracy, affordability and simplicity acceptable. To improve the efficiency of the system, a smart load controller (SLC) has been suggested. Applying SLC, extra current storage occurs when there is a sudden load change, otherwise little extra current is stored.