Non-inverting Buck-boost Converter Research Articles

A comparative study of voltage, peak current and dual current mode control methods for noninverting buck-boost converter

This paper presents a comparison of voltage mode control (VMC) and two current mode control (CMC) methods of noninverting buck-boost converter. The converter control-to-output transfer function, line-to-output transfer function and the output impedance are obtained for all methods by averaging converter equations over one switching period and applying small-signal linearization. The obtained results are required for the design procedure of feedback compensator to keep a system stable and robust. A comparative study of VMC, peak current mode control (PCMC) and dual-current mode control (DCMC) is performed. Performance evaluation of the closed-loop system with obtained compensator between these methods is performed via numerical simulations.

Hysteretic Transition Method for Avoiding the Dead-Zone Effect and Subharmonics in a Noninverting Buck–Boost Converter

A new hysteresis window method is proposed as a solution for avoiding the operational dead zone that exists at the transition between buck and boost operating modes in all noninverting buck-boost converters. In addition, this method also eliminates the discontinuities in the converter's steady-state output voltage transfer characteristic, which is a function of the duty cycle. The converter's output voltage function is surjective and, therefore, smooth mode transitions are achieved. The negative effects of operating within the dead zone are shown by the presence of subharmonics in the output voltage, increased output voltage ripple, poor regulation, and the instability of the converter during the transition between buck and boost operating modes. The dead-zone avoidance technique proposed in this paper eliminates all these issues while at the same time ensures highly efficient operation of the converter. An additional advantage of the technique is its simplicity, which allows for implementation into low-cost digital signal controllers, as well as into analog control circuits. The advantageous features of the proposed approach were evaluated on the basis of comparisons with three other dead-zone avoidance approaches and the initial case, which does not utilize any dead-zone avoidance technique. All the experiments were carried out on a purpose-built prototype of a noninverting buck-boost converter with magnetically coupled inductors.

Single-Phase Bridgeless Zeta PFC Converter with Reduced Conduction Losses

This paper presents a new single phase front-end ac-dc bridgeless power factor correction (PFC) rectifier topology. The proposed converter achieves a high efficiency over a wide range of input and output voltages, a high power factor, low line current harmonics and both step up and step down voltage conversions. This topology is based on a non-inverting buck-boost (Zeta) converter. In this approach, the input diode bridge is removed and a maximum of one diode conducts in a complete switching period. This reduces the conduction losses and the thermal stresses on the switches when compare to existing PFC topologies. Inherent power factor correction is achieved by operating the converter in the discontinuous conduction mode (DCM) which leads to a simplified control circuit. The characteristics of the proposed design, principles of operation, steady state operation analysis, and control structure are described in this paper. An experimental prototype has been built to demonstrate the feasibility of the new converter. Simulation and experimental results are provided to verify the improved power quality at the AC mains and the lower conduction losses of the converter.

Analysis of Dual-Carrier Modulator for Bidirectional Noninverting Buck–Boost Converter

A pulse-width modulation modulator for a noninverting bidirectional buck-boost converter is analyzed and a corresponding average-mode current controller design is revealed. The main feature of the modulator is the ability to create switching sequences for both converter legs without requiring any information regarding either operation mode or the direction of power flow. The modulator receives a control signal generated by the current controller, and a triangular carrier and generates driving signals with two different duty cycles, allowing tight control of the inductor current throughout the entire operating range. The underlying circuitry is thus relatively simple; moreover, the proposed method greatly simplifies the outer loop controller design. The revealed findings are supported by simulations and experiments.

A Stable Mode-Transition Technique for a Digitally Controlled Non-Inverting Buck–Boost DC–DC Converter

The propagation delay of a comparator and dead time causes the duty-discontinuity region near the boundary of the step-down and step-up regions in a non-inverting buck-boost (NIBB) converter. The duty-discontinuity region leads to an unstable output voltage and an unpredictable output voltage ripple, which might cause the entire power system to shut down. In this paper, a mode-transition technique called duty-lock control is proposed for a digitally controlled NIBB converter. It locks the duty cycle and eliminates the error between the output voltage and the reference signal by using a proposed fixed reference scheme that ensures the stability of the digital controller and output voltage. The experimental results that were applied to a field-programmable gate array-based platform revealed that the output voltage of the NIBB converter is stable throughout the entire transition region, without any efficiency tradeoffs. The input voltage of the converter that was provided by a Li-ion battery was 2.7-4.2 V, and the output voltage was 1.0-3.6 V, which is suitable for radio-frequency power amplifiers. The switching frequency was 500 kHz, and the maximum load current was 450 mA.

A DC-DC converter topology for multiple-input photovoltaic configurations

The voltages generated from renewable sources, such as wind and solar energy, often vary because of environmental changes. When the input voltage drops to a value lower than that of the battery, it will fail to recharge. Cascaded buck-boost converters are conventionally used to step-up or step-down the input voltage, but these are relatively complex and costly. This paper describes a new battery charging system based on a non-inverting buck-boost converter. The proposed two-switch converter requires one less inductor and capacitor compared with the conventional SEPIC (single-ended primary inductor converter) to achieve the non-inverted output voltage. The model is validated through simulation results from one and multiple sources with constant and variable input voltages. Test results show stable operating performance under both steady-state and transient conditions. A maximum power point tracking algorithm is successfully applied to the proposed multiple input converter configuration. The system is suitable for both low-voltage portable charging devices and grid-connected photovoltaic/battery systems.

결합 인덕터를 이용한 2상 양방향 비반전 벅-부스트 컨버터

This study proposes a two-phase non-inverting buck-boost converter that uses a coupled inductor. The multi-phase converter has many advantages over single-phase counterparts, such as reduced output current ripple and conduction loss in switching devices and passive elements. Although the output current ripple of the multi-phase converter is reduced significantly because of the interleaved effect, the inductor current ripple is not reduced in multi-phase converters. One of the solutions to this problem is to use a coupled inductor. A 4 kW prototype converter is built and tested to verify the performance of the proposed converter.

A High-Efficiency Bidirectional AC/DC Topology for V2G Applications

This paper proposes a single-phase bidirectional AC/DC converter topology applied in V2G systems, which consists of an inverter and a bidirectional non-inverting buck-boost converter. This topology can operate in four modes: buck charging, boost charging, buck discharging and boost discharging with high input current quality and unity input power factor. The inverter switches at line frequency, which is different from conventional voltage source inverters. A bidirectional buck-boost converter is utilized to adapt to a wider charging voltage range. The modulation and control strategy is introduced in detail, and the switching patterns are optimized to reduce the current ripple. In addition, the semiconductor losses are analyzed. Simulation and experimental results demonstrate the validity and effectiveness of the proposed topology.

Optimization of Subcell Interconnection for Multijunction Solar Cells Using DC-DC Converter

The extraction of solar energy will be higher using the multijunction solar cells instead of single junction solar cell by splitting the solar spectrum. This work proposes a detailed study to identify the optimum interconnection method for various multijunction solar cells. An effective power electronic circuit could substantially enhance the efficiency and utilization of a photovoltaic (PV) power system constructed from multijunction solar cells. The multiple input dc-dc non-inverting buck-boost converter is used to demonstrate the advantage of the proposed interconnection technique, which can maintain a constant output voltage by performing both the buck and boost mode of operation. In order to ensure maximum power point (MPP) operation, a particle swarm optimization (PSO) algorithm is applied which needs only one MPP control for multiple solar modules resulting reduction in cost and complexity. The PSO algorithm has the ability to track the global maxima of the system even under complex illumination situations.

Fuzzy/State-Feedback Control of a Non-Inverting Buck-Boost Converter for Fuel Cell Electric Vehicles

This paper presents an intelligent state feedback controller of a non-inverting buck-boost converter for fuel cell power sources. The proposed control strategy uses fuzzy logic control and state feedback control in order to combine advantages of both controllers. Fuel cell DC/DC converters often have to be able to both step-up and step-down the input voltage and provide a high efficiency in the whole range of output power. Non-inverting buck-boost converters provide both step-up and step-down characteristics. In this paper a state- space average model of converter is obtained and the effect of using a state feedback controller in order to stabilize and regulate the output voltage has been proposed. The use of intelligent state feedback controller allows choosing the proper pole placement of system and using inductor current as a feedback provides a fast dynamic response. Simulation results showed the capability of proposed control strategy during different conditions in fuel cell electric vehicles.

A Novel High-Efficiency Compact-Size Low-Cost Balancing Method for Series-Connected Battery Applications

This paper proposes a novel balancing method for series-connected batteries applications. The proposed method uses a transformer to couple the energy from charger or discharger to batteries for energy balancing. The proposed method has the advantages of high efficiency, compact size, suitable for any type of switching converter, load-related balancing energy, and extremely simple structure without any active switch for voltage balance function. Three converters, including a CLL converter, an interleaved noninverting buck-boost (BB) converter, and a noninverting BB converter, with voltage balancing function and state-of-charge balancing function are built to verify the feasibility of the proposed balancing methods.

Buck-Boost Converter Efficiency Maximization via a Nonlinear Digital Control Mapping for Adaptive Effective Switching Frequency

A nonlinear control loop mapping has previously been designed for mitigating the dead zone of a noninverting buck-boost converter while minimizing state variable perturbation. This paper derives a new nonlinearity that enables a converter with fixed switching frequency to achieve reduced switching loss as though operating at an effective switching frequency lower than the actual. The new control loop nonlinearity accomplishes this by interleaving a specified fraction of pass-through and nonpass-through switching periods. The derived nonlinearity also reduces the increase in waveform ripple associated with a switching frequency reduction. Through adapting the effective switching frequency across the full range of conversion ratios and loads, reductions in loss up to 58% are realized.

Fixed frequency sliding mode-based robust inversion with a full-bridge current DC-link buck-boost

The substitution of the original switches by a full bridge in a Non-Inverting Buck-Boost converter results in an inverter capable of carrying out step-down and step-up tasks as well under sliding mode control. The control law is implemented by means of the Zero Average Dynamics algorithm, which provides a fixed frequency operation and guarantees null error in each switching period, thus achieving a highly accurate tracking of periodic reference profiles. Furthermore, semi-infinite programming techniques are used to reduce power losses and, at the same time, prevent undesirable effects of control action saturation. The performance of the inverter is ensured to be robust in the face of bounded nonlinear and resistive loads. Realistic simulation results obtained with PSIMR software validate the proposed schemes.

A Novel Two Switch Non-inverting Buck-Boost Converter based Maximum Power Point Tracking System

A solar module can’t transfer maximum power to the load itself due to impedance mismatch. A maximum power point tracking (MPPT) system could be employed to have the maximum power. A new MPPT system has been developed using Buck-Boost type DC-DC converter. The system is highly efficient and robust. PIC16F73 microcontroller has been used to control the DC-DC converter output. PV module output power is measured using microcontroller. The output power is compared with the previous module output power and the duty cycle of the converter is adjusted continuously to track MPP. This process repeats until the output power reaches near to the maximum power point.In this paper, a maximum power point tracking (MPPT) system is developed using two-switch non-inverting buck-boost converter. Perturb and observe (P & O) MPPT algorithm is used to transfer maximum power from the PV panel which is executed using a microcontroller. DOI: http://dx.doi.org/10.11591/ijece.v3i4.2772

Resonant CLL Non-Inverting Buck-Boost Converter

This paper presents a resonant non-inverting buck-boost converter in which all switches operate under ZCS conditions. In a symmetric configuration, a CLL resonant tank along with an inverter arm and a rectifying diode are employed. The diode is turned off at ZCS and hence the problem of its reverse recovery is obviated also. As a result switching losses and EMI are reduced and switching frequency can be increased. The converter can work at DCM and CCM depend on the switching frequency and the load-current. Experimental results from a 200W/200KHz laboratory prototype verify operation of the proposed converter and the presented theoretical analysis.

A Nonlinear State Machine for Dead Zone Avoidance and Mitigation in a Synchronous Noninverting Buck–Boost Converter

A new nonlinear state machine is proposed as the solution to an operational dead zone near the buck/boost interface of the noninverting buck-boost converter. This dead zone avoidance and mitigation (DZAM) state machine transforms the sequence of buck and boost duty cycles applied to the converter to a new sequence which completely avoids the dead zone while largely shielding the rest of the converter from its presence. The state machine contains one of several possible embedded nonlinearities, the choice of which determines the exact characteristics of the DZAM algorithm and is application specific. Previously published attempts to deal with the noninverting buck-boost dead zone either double switching loss or apply only to systems with slowly changing input/output conditions. By contrast, the high-speed DZAM technique proposed here does not increase switching loss and operates autonomously, independent of external conditions, thereby allowing its use in all applications.

Design of an Average-Current-Mode Noninverting Buck–Boost DC–DC Converter With Reduced Switching and Conduction Losses

With the rapid growth of battery-powered portable electronics, an efficient power management solution is necessary for extending battery life. Generally, basic switching regulators, such as buck and boost converters, may not be capable of using the entire battery output voltage range (e.g., 2.5-4.7 V for Li-ion batteries) to provide a fixed output voltage (e.g., 3.3 V). In this paper, an average-current-mode noninverting buck-boost dc-dc converter is proposed. It is not only able to use the full output voltage range of a Li-ion battery, but it also features high power efficiency and excellent noise immunity. The die area of this chip is 2.14 × 1.92 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , fabricated by using TSMC 0.35 μm 2P4M 3.3 V/5 V mixed-signal polycide process. The input voltage of the converter may range from 2.3 to 5 V with its output voltage set to 3.3 V, and its switching frequency is 500 kHz. Moreover, it can provide up to 400-mA load current, and the maximal measured efficiency is 92.01%.

An asynchronous finite-state-machine-based buck-boost converter for on-chip adaptive power supply

In this paper we present an asynchronous finite-state machine digital controller co-integrated with an on-chip non-inverting buck-boost power converter with dynamic signal-tracking capabilities. The mostly-digital controller functionally implements a non-PWM zone-wise control law through asynchronous circuitry, thus exhibiting self-timed minimum latency and ultra low power operation due to gate switching activity. Experimental results on a 0.35 μm CMOS technology demonstrate an efficiency up to 80 % with a switching frequency of 2.86 MHz.

A Self-Powered Power Conditioning IC for Piezoelectric Energy Harvesting From Short-Duration Vibrations

This brief presents a piezoelectric vibration power conditioning integrated circuit for energy autonomous sensor applications. The proposed circuit includes a negative voltage converter, a noninverting buck-boost converter working in discontinuous conduction mode (DCM), and a switching clock generator. Optimum load resistance is synthesized by the DCM buck-boost converter to achieve maximum power extraction, and system conduction loss is reduced by a novel arrangement of a current rectification diode within the buck-boost converter. This circuit is able to harness power from short-duration vibration and self starts up with a minimum 0.9-V input voltage. The proposed circuit has been implemented in a standard 0.18-μm CMOS process with 0.05-mm2 active area and achieved a maximum power conversion efficiency value of 54%.

A Noninverting Buck–Boost DC–DC Switching Converter With High Efficiency and Wide Bandwidth

A novel dc-dc switching converter consisting of a boost stage cascaded with a buck converter with their coils magnetically coupled is presented. The disclosed converter has the same step-up or step-down voltage conversion properties than the single inductor noninverting buck-boost converter but exhibits nonpulsating I/O currents. The converter control-to-output transfer function is continuous between operation modes if a particular magnetic coupling is selected. The addition of a damping network improves the dynamics and results in a control-to-output transfer function that has, even in boost mode, two dominant complex poles without right-half-plane zeros. An example shows that an output voltage controller can be designed with the same well-known techniques usually applied to the second-order buck regulator. Details of a prototype and experimental results including efficiency, frequency, and time domain responses are presented. The experimental results validate the theoretical expected advantages of the converter, namely, good efficiency, wide bandwidth, and simplicity of control design.