Quadratic Buck-boost Converter Research Articles

Output Ripple Voltage Analysis of Quadratic Buck–Boost Converters with Switched Inductor Network in the Entire Dynamic Range

In order to provide theoretical guidance for the design of quadratic Buck–Boost converter with switched inductor network, the minimum current flowing through the energy storage inductor L3 is compared with the output current and zero, the working mode of the converter can be divided into the complete inductor supply in continuous conduction mode(CISM-CCM), the incomplete inductor supply in continuous conduction mode(IISM-CCM)and the incomplete inductor supply in discontinuous conduction mode(IISM-DCM). Within the given input voltage and load range, the working region of the converter is divided into five parts according to the different value of the inductor L3. By analyzing the output ripple voltage of the converter in the five working areas, and the maximum output ripple voltage of the converter is obtained. Based on the relationship between the maximum output ripple voltage of the entire dynamic range and the value of the inductor L3, it is pointed out that the output voltage ripple of the converter in CISM-CCM is the smallest and independent of the inductor L3, and that the output voltage ripple in IISM-CCM and IISM-DCM is much larger and increasing with the decreasing of the inductor L3. Meanwhile, it is concluded that the minimum inductance to guarantee the lowest output ripple voltage is the critical inductance between CISM-CCM and IISM-CCM. Finally, the experimental results verify the rationality and correctness of the theoretical analysis.

A Single-Stage Charger for LEV Based on Quadratic Buck-Boost AC-DC Converter Topology

A single-stage AC-DC converter, which uses a quadratic buck-boost voltage gain, for LEVs' (Light Electric Vehicles) battery charging is presented in this work. Unlike conventional BCs (Battery Chargers), which employ transformer (low or high frequency) based approaches to charge low voltages LEVs' batteries, the presented charger utilizes transformerless single-stage power architecture. In order to realize desired charging of LEVs and to maintain proper transformerless voltage gain, the presented quadratic buck-boost AC-DC converter ensures high step-down gain characteristics between AC mains and low voltage battery packs. Besides realizing desired battery charging profile, the presented single-stage BC ensures high PQ (Power Quality) indices (low input current distortions and unity power factor operation) at the supply side. Notably, the presented quadratic buck-boost AC-DC converter exhibits an intrinsic power factor correction (PFC) feature at the AC input mains under discontinuous inductor current mode (DICM) operation, thereby, incurring minimum complexities during the control implementation, which further reduces the cost of the charger. The DICM operation facilitates negligible switch turn-on and diode reverse recovery losses, and therefore, ensures an improved conversion efficiency of the BC. Even if, the presented AC-DC converter employs two switching devices, the simultaneous switching of both switches shrinks the cost and complexity of driving circuitry even further. Finally, a comprehensive operational analysis, component selection criteria, and modelling of the presented quadratic buck-boost AC-DC converter-based LEVs BC are carried out and its performance is validated through a test bench set-up in a laboratory environment. Relevant results are presented to validate the efficacy of the presented quadratic buck-boost AC-DC converter for LEVs charging applications.

A Quadratic Buck-Boost Converter With Continuous Input and Output Currents

This study proposes a novel DC-DC converter topology that features a quadratic buck-boost voltage gain ratio. The quadratic gain of the converter enables it to achieve superior step-down or step-up capability when the duty cycle is higher or lower than 50 percent, as compared to conventional buck-boost converters. While there exist other quadratic buck-boost converters in the literature, the proposed converter offers unique features such as continuity of input and output currents, which reduces the current stress on the input and filter capacitors, making it a suitable option for renewable energy applications. Additionally, unlike its counterparts that have two high-side switches, the proposed converter features only one high-side and one low-side switch, allowing for a simpler gate-driver design. The proposed topology shares a common ground between the load and the source, and has the lowest stored energy with the same performance, indicating a compact size. Steady-state analysis has been conducted in both continuous and discontinuous conduction modes, and the controller design was studied with the aid of small-signal modelling. Simulation and experimental results from a 100 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">W</i> prototype were used to validate claims and analyses.

Non-Inverting Quadratic Buck–Boost Converter with Common Ground Configuration for Supercapacitor Applications

This article presents a novel buck–boost converter-based topology suitable for supercapacitors and grid-connected solar PV system applications. The proposed converter can handle a wide range of voltage variations at the input side, making it ideal for extracting most of the energy from supercapacitors or a solar PV system connected to the input side of the converter. The output voltage of the converter is non-inverting which makes the control easier. The design of passive components, continuous mode operation, and discontinuous mode operation are all thoroughly discussed. A low-power hardware prototype of three hundred watts is developed and tested in the laboratory to validate the theoretical aspects of the converter.

Analysis of Inductor Peak Current Based on the Quadratic Buck-Boost Converter with Switched Inductor Network in the Entire Dynamic Range

According to the working principle of the proposed quadratic Buck-Boost Converter with Switched Inductor Network, the converter is divided into continuous conduction mode (CCM) and discontinuous conduction mode (DCM) according to whether the minimum current flowing through the inductor L3 is equal to zero. Subsequently, the inductor peak current in the two modes are derived. Based on the quadratic Buck-Boost Converters with Switched Inductor Network, a entire dynamic range inductor peak current analysis method is proposed within a given input voltage and load range. Meanwhile, In terms of different value ranges of the inductor L3, the working area of the converter is divided into three parts, and the maximum inductor peak current in the three working conditions are compared. By analyzing the relationship between the maximum inductor peak current and the value of the inductor L3, it is concluded that L3 = L3CA is the critical inductance at which the maximum inductor peak current of the converter reaches the minimum in the entire dynamic range. Finally, the experimental results demonstrate the reasonability and correctness of the proposed theoretical analysis.

A High Step Up Multi-Input DC/DC SEPIC-Based Converter with Coupled Inductor for Renewable Applications

To overcome low output voltage of renewable energy sources such as photovoltaic arrays and fuel cells, a high step up SEPIC-based multi-input converter with dual coupled inductor is proposed. A new structure is presented in this paper, as an improved structure. This converter is based on combination of modified quadratic buck-boost converter, Dickson switched capacitor (DSC), and voltage multiplier modules (VMM). The high voltage gain can be achieved by adjusting the duty cycle and turn ratio of coupled inductor of VMM. This structure inherits all the advantages of the SEPIC converter such as step-up/down capability without inverting the polarity of regulated output voltage and using a bidirectional input port (in which an energy storage system (ESS) can be connected), and several unidirectional input ports. The load power can be flexibly divided among various power sources. Due to the buck-boost characteristics of the presented converter, it is suitable to charge-discharge the ESS. A coupled inductor (CI) is used to couple energy from input to the output equipped with the VMM. The usage of the DSC technique also enables the converter to obtain an additional double voltage gain while reducing the voltage stress on switches. Simulation results verify the performance of the proposed converter and feasibility of the control strategy.

MODIFIED QUADRATIC BUCK BOOST CONVERTER FOR PV APPLICATIONS

Buck-boost DC/DC converters have been extensively employed in stepping up/down the voltage for PV applications. The input and the output port current of the traditional quadratic buck-boost converter are discontinuous, which result in increased input and output current ripples and complicate the design of the input and output filters. Hence these problems can be solved by using a modified quadratic buck boost converter, which provides wider voltage conversion ratio with continuous input and output ports current. Dual output can be derived from this single input converter for multiple output applications. Also a fuzzy logic controller can be designed for this proposed converter for better and faster performance.

Implementation of Bi-directional Capabilities of Batteries for using Quadratic Buck-Boost Converter

Implementation of Bi-directional Capabilities of Batteries for using Quadratic Buck-Boost Converter

A continuous input and output current quadratic buck-boost converter with positive output voltage for photovoltaic applications

This paper proposes a transformerless buck-boost DC-DC converter with positive output voltage. The voltage gain of the proposed buck-boost converter is square of voltage gain of conventional one. Therefore, the proposed converter can operate in a wide range of output voltage. Contrary to the conventional buck-boost converter, the proposed converter benefits from continuous input current, which makes it more suitable for renewable energy applications. Furthermore, the output current of the proposed converter is also continuous, which alleviates the current stress on the output capacitor and brings down the output voltage ripple. Principle operation, steady-state investigation, efficiency analysis and small signal modeling are addressed in detail for continuous conduction mode (CCM). Moreover, the proposed converter is compared to other quadratic buck-boost topologies in terms of different criteria. Finally, the performance of the proposed converter is verified through experimental results.

Quadratic Buck–Boost Converter With Zero Output Voltage Ripple at a Selectable Operating Point

We introduce a new dc–dc converter topology with the following features: first, quadratic voltage gain, which allows the converter to work over a wide voltage range with a minimal variation of duty cycle and without the use of extreme duty cycles; second, output voltage ripple mitigation, which can be accomplished with respect to a fixed but otherwise arbitrary duty cycle by proper selection of components and switching signals. Since the proposed converter can be designed to have zero output voltage ripple for the nominal gain (duty cycle), this allows the use of small values of capacitances. The underlying principles and steady-state equations in continuous conduction mode are presented in detail. Experimental tests are presented to validate the analysis.

Nonlinear Analysis of Hysteretic Modulation-Based Sliding Mode Controlled Quadratic Buck–Boost Converter

In this paper, the dynamics of hysteresis current-controlled quadratic buck-boost converter is investigated in detail. The system model is derived based on the sliding mode approach and also in its dimensionless form for algebraic brevity. The stability of the system is disclosed with the aid of the movement of eigenvalues. Onset of Hopf bifurcation is identified when the complex conjugate eigenvalue pair crosses the imaginary axis of the complex plane. The stability boundary is drawn to benefit the power electronics engineer for a stable and reliable design. The computer simulation of the switched model is performed using MATLAB/Simulink software to uncover the sequential occurrence of nonlinear behavior exhibited due to Hopf bifurcation for variation in control parameters and the input voltage. The phase portrait disclosing the subtle periodicity is plotted at different operating points to elicit that the stable period-1 attractor bifurcates to the quasi-periodic orbit and finally to a limit cycle. The precise dynamic of the phase portrait is also captured using the Poincare section. Experimental outputs are presented for confirming the low-frequency bifurcation scenario witnessed in the simulated and analytical results.

A Single-Switch Quadratic Buck–Boost Converter With Continuous Input Port Current and Continuous Output Port Current

A single-switch quadratic buck–boost converter with continuous input port current and continuous output port current is proposed in this paper. Compared with the traditional buck-boost converter, the proposed converter can obtain a wider range of the voltage conversion ratio with the same duty cycle. Moreover, the proposed converter can operate with continuous input port current and continuous output port current compared to the existing counterparts with inherently discontinuous input port current and discontinuous output port current. The operating principle and steady-state performance of the proposed converter under continuous inductor current mode is analyzed in detail. Then, the comparison between the proposed converter and the existing quadratic buck–boost converters has been conducted to demonstrate the unique features of the proposed one. Finally, experimental results from a prototype built in the lab are recorded to verify the effectiveness and validity of the proposed quadratic buck–boost converter.

Implementation of Grid Connected PV array using Quadratic DC-DC Converter and Single Phase Multi Level Inverter

Electrical energy generation from solar and wind is increasing day by day and the extraction of good quality electrical energy effectively as well as efficiently is really challenging. This paper focuses on the extraction of electrical energy from solar cells and interconnecting it to the single phase grid through a Quadratic Buck-Boost Converter (QBBC) and Multi Level Inverter (MLI). MLI uses three DC sources, one of which is derived from the solar array through QBBC with Maximum Power Point Tracking (MPPT) controller. In this paper, a new converter topology which accepts wide variations in input voltage has been designed to produce minimum distortion in MLI output with reduced number of switches. The proposed system is designed and implemented in the laboratory and the output is analyzed in different operating conditions

Generation, Analysis of Switched Mode Dc to Dc Converters by the Use of Converters Cells

The conventional PWM converter topologies limit the operation to lower switching frequencies because of the minimum ON-time of the transistor switch. The quadratic feature is interesting for application where a wide voltage range is necessary, a quadratic buck-boost converter is presented. The converter cell is showed, the quadratic buck converter with the converter cell can convert to the quadratic buck-boost converter without increasing elements.