Search Results (4)

In order to meet the demand for high-voltage architectures of 400 V and 800 V in electric vehicle systems, high-power DC-DC converters have become a key focus of research. The Four-Switch Buck–Boost converter has gained widespread application due to its wide voltage conversion range, consistent input and output polarity, and the capability of bidirectional power transfer. This paper focuses on the energy conversion requirements in high-voltage scenarios for electric vehicles, analyzing the working principle of this converter and typical control strategies. It summarizes the issues encountered under different control strategies and presents improvements. Hard-switching multi-mode control strategies aim to improve control algorithms and logic to mitigate large duty cycle variations and voltage gain discontinuities caused by dead zones. For control strategies based on controlling the inductor current to achieve soft-switching, the discussion mainly focuses on optimizing the implementation of soft-switching, reducing overall system losses, and improving the computation speed. Finally, the paper summarizes FSBB control strategies and outlines future directions, providing theoretical support for high-voltage fast charging and onboard power supplies in electric vehicles. Full article

This paper presents the analysis and design of an isolated bidirectional DC-DC converter for applications where both input and output voltages may vary in a wide range. The proposed topology is derived from the integration of an isolated Current-Fed Dual-Active-Bridge (CF-DAB) stage with a Four-Switch Buck-Boost cell (4SBB), sharing one switching leg. Detailed design procedures are outlined for both CF-DAB and 4SBB stages, allowing to achieve Zero-Voltage turn-on of all devices while minimizing the inductor current RMS values. An optimized design of the CF-DAB coupled inductors allowed to achieve the desired leakage inductance value without the need for an additional magnetic component. Experimental results taken on a 5 kW prototype interfacing two voltage ports with V_L ∈ [42 V, 72 V], V_H ∈ [225 V, 435 V] validate the proposed design procedure. Full article

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 $\mathsf{\mu }$F, with 80 Vpp output and 2.75% total harmonic distortion (THD) observed in the test. Full article

This article presents the modeling and optimization control of a hybrid water pumping system utilizing a brushless DC motor. The system incorporates battery storage and a solar photovoltaic array to achieve efficient water pumping. The solar array serves as the primary power source, supplying energy to the water pump for full-volume water surrender. During unfavorable weather conditions or when the photovoltaic array is unable to meet the power demands of the water pump, the battery discharges only at night or during inadequate solar conditions. Additionally, the photovoltaic array can charge the battery on its own when water distribution is not necessary, negating the need for external power sources. A bi-directional charge control mechanism is employed to facilitate automatic switching between the operating modes of the battery, utilizing a buck-boost DC–DC converter. The study incorporates a control system with loops for battery control and DC voltage control within the bidirectional converter. The water cycle algorithm adjusts four control parameters by minimizing an objective function based on tracking errors. The water cycle optimization is compared to other methods based on overshoot and settling time values to evaluate its performance, showcasing its effectiveness in analyzing the results. Full article