Four-switch Buck-boost Converter Research Articles

Unified One-Cycle Control for Fully Digitalized ZVS Four-Switch Buck–Boost Converter During Bidirectional Power Flow Transition

Unified One-Cycle Control for Fully Digitalized ZVS Four-Switch Buck–Boost Converter During Bidirectional Power Flow Transition

Adaptive Fast Integral Terminal Sliding Mode Control Strategy Based on Four-Switch Buck–Boost Converters

With the rapid development of electronic power systems, DC-DC converters are widely used, including the Four-Switch Buck–Boost (FSBB) converter, which has a unique advantage in scenarios with a wide range of voltage inputs. To improve the response speed and anti-interference capability of the FSBB converter, this paper proposes an adaptive global fast integral terminal sliding mode control method. Through an in-depth analysis of the fundamental characteristics of the FSBB converter, this study employed a global fast integral terminal sliding mode controller combined with an adaptive algorithm to significantly improve the dynamic performance and robustness of the FSBB converter. The simulation and experimental results show that the proposed method could track the reference voltage quickly and accurately in different modes, exhibiting excellent system robustness compared to conventional sliding mode control, terminal sliding mode control, and PID control methods.

Seamless multi‐mode switching controller of four‐switch buck–boost converter based on integrated natural trajectory method

SummaryWith the characteristics of high efficiency and high power density, the four switch buck–boost (FSBB) converter is widely used in electric vehicles, direct current microgrids, and so forth. However, how to achieve smooth switching between different modes of FSBB has always been a hot issue in the theoretical and engineering fields. In this paper, considering the dynamic performance and output voltage or inductance current deviation, a control algorithm with integrated natural trajectory method is designed to realize the switching of different modes of FSBB converter. The proposed control algorithm is based on the theory of large signal natural locus and average natural locus. The normalized phase locus of inductance current and output voltage divides the phase plane into five regions and performs large signal or average switching operations in different regions. Theoretical analysis shows that the proposed control algorithm can achieve the balance between the dynamic performance and output voltage or inductance current deviation of FSBB converter in different mode switching. Finally, the performance of the proposed control algorithm is verified by experiments results.

Design of a PWM/PFM hybrid modulation switching circuit for a four-switch buck-boost converter

Based on the application background of fuel cell, the conversion efficiency of the four-switch Buck-Boost converter using PWM (Pulse width modulation) is low at light load, and the conversion efficiency of the four-switch Buck-Boost converter using PFM (Pulse frequency modulation) is low at heavy load. A PWM/PFM hybrid modulation circuit using digital module to detect induced current and feedback voltage is presented. The circuit structure is simple and easy to integrate. It has the effect of fast selection according to inductance current and feedback voltage. The circuit works in PWM mode by default. After soft startup, PWM/PFM mode can be switched according to the load. Finally, simulation is carried out in FSBB converter. The experimental results show that the PWM/PFM hybrid modulation circuit has the function of multi-load lead switching mode and protection mechanism. Simulation in FSBB converter shows that the converter efficiency reaches 91.99% and the maximum load current is 2A. This helps improve the efficiency of Buck-Boost converters.

A study of converter configurations for vehicular applications

Renewable energy sources like hydro, wind, geothermal and solar along with fuel cells are nowadays solutions to the global energy crisis, environmental issues, and fossil fuel exploitation. The nature of the output of these renewable sources is D.C. The role of DC-DC converters in the integration of energy sources with microgrids is vital. These converters find their major applications in power generation, energy systems, vehicular applications, portable electronic devices, aerospace, etc. These converters help to boost the voltage and improve the reliability, stability, efficiency, and performance of the system. This study gives a brief overview of three DC-DC converters of non-isolated topology. They are: Clamped H-type boost DC-DC converter, Multi-Port Dual-Active-Bridge DC-DC Converter, and Four-Phase Interleaved Four-Switch Buck-Boost Converter. This study will make researchers learn and make their concept clear about the operation, performance, and usage of these converters.

Lagrange-Multiplier-Based Control Method to Optimize Efficiency for Four-Switch Buck–Boost Converter Over Whole Operating Range

Four-mode modulation method is the most advanced for four-switch buck-boost (FSBB) converter among existing control strategies. But its efficiency is still not optimal. In this study, all four-mode modulation methods are analyzed, and the minimum inductor current root mean square (RMS) value of each four-mode modulation method is obtained via the generalized Lagrange multiplier method. Under this circumstance, the optimal four-mode modulation methods are selected to form a control method that improves operating efficiency over the whole operating range. Experimental results and comparison with state-of-the-art methods demonstrate the effectiveness and superiority of proposed method.

A Multi-Frequency PCCM ZVS Modulation Scheme for Optimizing Overall Efficiency of Four-Switch Buck–Boost Converter With Wide Input and Output Voltage Ranges

The pseudo-continuous conduction mode (PCCM) zero-voltage-switching (ZVS) modulation scheme is widely used in the four-switch buck-boost (FSBB) converter to achieve high efficiency and voltage step-up/step-down without modulation mode transition. There are two degrees of modulation freedom in the PCCM ZVS modulation scheme. The previous schemes typically only optimize one of them to reduce root mean square (rms) inductor current, which results in relatively lower efficiency in the condition when the difference between input voltage and output voltage is large. In this paper, a multi-frequency PCCM ZVS modulation scheme is proposed for the FSBB converter with wide input and output voltage ranges. By optimizing both of the two degrees of modulation freedom to reduce rms inductor current, the heavy-load efficiency can be effectively improved when the difference between input voltage and output voltage is large. Thus, the overall efficiency of the FSBB converter can be optimized. A 1500W FSBB prototype with input and output voltage ranges of 200-400V is built to verify the proposed modulation scheme.

Efficiency Optimization and Control Strategy of Four-Switch Buck–Boost Converter for Wide Conversion Ratio

An improved control strategy for the four-switch buck-boost (FSBB) converter is proposed to improve the efficiency in a wide conversion ratio and wide loads. The conventional duty-cycle-controlled FSBB converter can not achieve the zero-voltage switching (ZVS) for all the switches, while the converter has a dead zone issue. The proposed control strategy is controlled by the duty cycle and phase shift control. The control law is derived from the analytical solution of the optimized current stress with the constraint of the ZVS for all the switches. The working modes in the proposed control strategy can cover the whole load in a wide conversion ratio. Furthermore, the dead zone issue is removed. The modulation surface and output power surface versus the conversion ratio and control variable demonstrate the working modes are switched seamlessly. The control strategy is implemented in the digital controller. Finally, the experimental results verify the higher efficiency and dynamic performance of the control strategy.

A 3-to-5 V Input, 80 Peak-to-Peak Voltage (Vpp) Output, 2.75% Total Harmonic Distortion Plus Noise (THD+N), 2.9 μF Load Piezoelectric Actuator Driver with Four-Switch Buck–Boost

As human–computer interaction has become increasingly popular, haptic technology has become a research topic of great interest, since vibration perception, as a type of haptic feedback, can enhance user experience during an interaction. However, the high power consumption of existing drivers makes them unsuitable for use in portable devices. In this paper, a bidirectional four-switch buck–boost converter (FSBBC) and Proportional–Integral (PI)–Proportional (P) feedback control are proposed to implement a driver in a high-capacitance piezoelectric actuator which is capable of recovering the energy stored in the high-capacitance load and increasing efficiency. The FSBBC offers an extended input voltage range, rendering significant technological advantages in diverse applications such as automobiles, laptops, and smartphones. By implementing specific control strategies, the FSBBC not only outperforms conventional buck–boost converters in boosting performance, but also ensures that the output and input voltages retain the same polarity. This effectively addresses the polarity inversion challenge inherent to traditional buck–boost circuits. Within the FSBBC, the significant reduction in voltage stress endured by the MOSFET effectively minimizes system costs and size and enhances reliability. The proposed system was simulated in Simulink, which was combined with testing on a field-programmable gate array (FPGA). The driver is capable of driving capacitors of up to 2.9 μF, with 80 Vpp output and 2.75% total harmonic distortion (THD) observed in the test.

Design and Performance Evaluation of SMC-Based DC–DC Converters for Microgrid Applications

In recent times, DC microgrids (MGs) have received significant attention due to environmental concerns and the demand for clean energies. Energy storage systems (ESSs) and photovoltaic (PV) systems are parts of DC MGs. This paper expands on the modeling and control of non-isolated, non-inverting four-switch buck-boost (FSBB) synchronous converters, which interface with a wide range of low-power electronic appliances. The proposed power converter can work efficiently both independently and in DC MGs. The charging and discharging of the battery are analyzed using the FSBB converter at a steady state in continuous conduction mode (CCM). A boost converter is connected to a PV system, which is then connected in parallel to the battery to provide voltages at the DC bus. Finally, another FSBB converter is connected to a resistive load that successfully performs the boost-and-buck operation with smooth transitions. Since these power converters possess uncertainties and non-linearities, it is not suitable to design linear controllers for these systems. Therefore, the controlling mechanism for these converters’ operation is based on the sliding mode control (SMC). In this study, various macro-level interests were achieved using SMC. The MATLAB Simulink results successfully prove the precise reference tracking and robust stability in different operating modes of DC–DC converters in a MG structure.

A Constant Frequency ZVS Modulation Scheme for Four-Switch Buck–Boost Converter With Wide Input and Output Voltage Ranges and Reduced Inductor Current

The pseudo continuous current mode (PCCM) four-switch buck-boost (FSBB) converter with negative valley inductor current is suitable for applications where zero-voltage-switching (ZVS) and voltage step-up and step-down are required. To improve its efficiency, many ZVS modulation schemes have been proposed to minimize the root mean square (RMS) inductor current. However, when both input and output voltage ranges are wide, the three-dimensional (3D) look-up table (LUT) with huge data quantity or the switching frequency with wide variation range is typically required in previous schemes. In this paper, a ZVS modulation scheme with constant switching frequency and simple real-time calculation is proposed. Only with a 2D LUT in a small range of input and output voltage, RMS inductor current can be minimized. Moreover, the switching frequency is constant with the proposed scheme. In addition, ZVS conditions, which are accurate and simple, are derived to facilitate the minimization of RMS inductor current. A 1500W FSBB prototype with input and output voltage ranges of 200-400V is built to verify the proposed modulation scheme and derived ZVS conditions.

Design of Four-Switch Buck-Boost Converter for Light Electric Vehicles: A Cost and Efficiency Perspective

Design of Four-Switch Buck-Boost Converter for Light Electric Vehicles: A Cost and Efficiency Perspective

Bidirectional Buck–Boost Converter With Reduced Power Loss and No Right-Half-Plane Zero

This article presents a novel hybrid bidirectional buck–boost converter (HBBC) for lithium-ion battery management. Unlike the conventional four-switch buck–boost converter (FBBC), whose power efficiency is greatly limited at heavy loads mainly due to high conduction loss from a high dc resistance (DCR) inductor, the proposed HBBC adopts assisted capacitive paths to reduce the current stress on the main inductive path. Thus, the conductive loss of inductor's DCR is greatly reduced in both the buck and boost modes. To verify the effectiveness of the proposed structure, detailed analyses on both the loop performance and conduction loss are provided. Compared with FBBC, the conversion efficiency of the proposed HBBC is increased by 23.3% in the boost mode, and the peak efficiency is up to 97.8% with an adopted inductor with a DCR of 270 mΩ.

Model Predictive Control for Four-Switch Buck–Boost Converter Based on Tuning-Free Cost Function With Smooth Mode Transition

Four-switch buck-boost (FSBB) converter has the capability of bidirectional voltage step-down and step-up, which has attracted attentions in the fields of energy storage and solar energy. However, it faces the challenges in multimode operation and smooth mode transition, which rely on the complex mode detection scheme and cumbersome parameter tuning. In this article, the inherent limitation is analyzed through inconsistent frequency response and noncontinuous duty cycle operation region aspects. Then, a model predictive control (MPC) method characterized by tuning-free cost function is presented to achieve multimode control and smooth transition simultaneously. With the goal of ensuring the reference current tracking under inconsistent frequency response, a duty cycle and current ripples prediction are presented for all switching combinations. Then, a tuning-free cost function is utilized to overcome the gaps in noncontinuous duty cycle operation region and a smooth mode transition is achieved. Further, the robustness of the current tracking capability is analyzed mathematically considering the inductance variation and stray resistance variation. Finally, a comparative experiment proves the effectiveness. And it shows that the method can improve the efficiency by 0.4% compared with the traditional four-mode control.

A PWM Plus Phase-Shift Control for Four-Switch Buck-Boost Converter to Achieve ZVS in Full Input Voltage and Load Range

Four-switch buck-boost (FSBB) converter features positive output voltage and low voltage stress of power switches. In this article, a pulsewidth modulation plus phase-shift control scheme is proposed to achieve zero-voltage-switching for all the power switches in full input voltage and load range and minimize the inductor current ripple and root mean square (RMS) value. The implementation of the proposed control scheme is given. A prototype of a 500-W FSBB converter is built and tested in the lab, and the experimental results verify the effectiveness of the proposed control scheme.

Research and Design of LC Series Resonant Wireless Power Transfer System with Modulation Control Method for Supercapacitor Charging in Linear Motion Systems

With the hot topic of “Carbon Neutrality”, energy efficiency and saving practices such as reducing fuel consumption, vigorously advocating new energy power and modern rail are now becoming the main research topics of energy conversion technologies. Supercapacitors, with their ability of higher power density, fast charging, and instantaneous high current output, have become an indispensable energy storage element in modern traction systems for modern rail. This proposal introduced wireless power transfer technologies by using LC series resonant technology for charging the supercapacitors. To match the voltage and current level of the supercapacitor, a four-switch buck-boost converter was applied on the secondary side of the load-matching converter. To regulate the wireless transfer power and charging power of the supercapacitor, the active modulation control method was introduced on both the primary and secondary sides of the transfer system. On the primary side, the power is controlled by controlling the current in resonant inductance through the phase shift control method, while on the secondary side, the charging power is controlled by regulating the input voltage of the four-switch buck-boost converter followed by inductance current control. The theoretical analysis under phase shift mode for the primary side and pulse width modulation for a four-switch buck-boost converter with a supercapacitor load (voltage source) were proposed in detail, and the state-space model of the load matching converter was established for controller design to obtain precise voltage and current control. Both open loop and closed loop simulation models were built in the MATLAB/SIMULINK environment, and simulations were carried out to evaluate the system characteristics and control efficiency. The experimental platform was established based on a dsPIC33FJ64GS606 digital controller. Experiments were carried out, and the results successfully verified the effectiveness of the system.

Synchronous Control Strategy with Input Voltage Feedforward for a Four-Switch Buck-Boost Converter Used in a Variable-Speed PMSG Energy Storage System

The four-switch Buck-Boost (FSBB) converter can produce voltage conversion within a wide input voltage range, which is suitable for variable-speed permanent magnet synchronous generator (PMSG) energy storage systems with AC inputs and DC outputs. To reduce the interference of input voltage fluctuation on the performance of the FSBB converter, an input voltage feedforward (IVFF) compensation method is proposed in this paper. The switching synchronization strategy is simple. Using the switching average model, the small signal model of a non-ideal FSBB converter in all working modes is established. The effects of input voltage, load current, damping coefficient and right half plane (RHP) zero on the stability of the control system are analyzed in detail. The transfer function of the IVFF of the FSBB converter is derived, and the relationship between input voltage, load current and duty cycle is analyzed. Finally, the design of the parameters of the converter control system is presented. The simulation and experimental results show that this FSBB converter has high efficiency and a good transient response.

An Improved Quadrangle Control Method for Four-Switch Buck-Boost Converter With Reduced Loss and Decoupling Strategy

Four-switch buck-boost (FSBB) converter is widely used in battery applications due to the simple structure and the excellent performance of both voltage step-up and step-down. With the quadrangle control method, FSBB converter can realize zero voltage switching (ZVS) of all power switches, and thus can adapt to the high-frequency trends. However, the conventional quadrangle control method has two problems: 1) the efficiency degradation caused by the large root mean square (RMS) current of the inductor, and 2) the instability caused by the coupling relationship between multiple control variables. In this article, an improved quadrangle control method is proposed to solve the two problems, making FSBB converter a good candidate for high-frequency battery applications. First, the loss analysis is built to determine the relationship between loss and the control variables. Then, the conditions to achieve the minimum loss are obtained. Second, the decoupling compensation strategy is applied to free the coupling relationship to improve the stability. The proposed strategy can achieve three control goals: 1) ZVS of all power switches; 2) minimize the total loss; and 3) stable closed-loop system. Finally, a 1MHz 280W FSBB prototype is built to verify the proposed control method. The prototype achieves all control goals and 98.1% peak efficiency.

Development of a Four-Switch Buck-Boost Converter: Operation Modes, Control and Experimental Results

This paper presents the development and practical implementation of a four-switch buck-boost converter for variable input voltage. The circuit operates in buck or boost mode when the input values are higher or lower than the output. For voltages near the required level, the traditional buck-boost mode is replaced by modes A and B consisting in the combination of some periods working in buck mode with others working in boost mode. The sequence and duty cycle assignment of these transition modes are defined according to an approach based on steady-state analysis and discrete-time models. The digital system is completed by the addition of a voltage control loop that regulates the output under possible perturbations. Experimental results show that the proposed modes A and B present less ripple and appreciable less losses than the buck-boost counterpart. Thus, the prototype achieves efficiencies above 95% for all the input range and nominal load.

A Constant Frequency ZVS Control System for the Four-Switch Buck–Boost DC–DC Converter With Reduced Inductor Current

A constant frequency zero-voltage-switching (ZVS) control strategy with a minimum root mean square (rms) value of inductor current is proposed in this letter for the four-switch buck-boost (FSBB) dc-dc converter that is used as a 48 V intermediate bus pre-regulator in distributed power systems. The quadrilateral inductor current modulation is adopted to achieve ZVS operation. The four control time intervals are optimally selected such that the inductor current rms value is minimized, thus reducing the conduction loss. The proposed closed-loop ZVS control scheme can be implemented without sensing the load current, although the rms minimum current algorithm needs the input and output voltages and load current at given a steady-state condition. The control scheme is verified in a 300 W dc-dc prototype of the ZVS FSBB converter. The input voltage and load transition tests are provided to verify the closed-loop characteristics without sensing load current.