Submodule mismatch has become the major cause of losses in the photovoltaic (PV) power generation system, which has been an important factor restricting the development of PV technology. Differential power processing (DPP) architecture is increasingly employed in PV distributed MPPT (DMPPT) due to its low processed power. In order to improve the PV utilization efficiency, minimize the power loss and reduce the system cost, a novel scheme based on DPP is introduced in this article. The proposed DPP converter is composed of multiple buck-boost choppers, and a multidimensional perturb and observe (MPO) algorithm is proposed to achieve true DMPPT through correcting the voltage of each submodule to its voltage at the maximum power point by using a single current sensor. A prototype with multiple buck-boost choppers for 36 V/200 W PV module is designed and built to verify the operating principle and evaluate the performance of the proposed DPP converter and DMPPT strategy, and the experimental results show that the prototype is low-cost and effectively improves system efficiency.

Compared to three-phase motors, multiphase motors (MPMs) can achieve higher power output, less motor torque pulsation, superior fault-tolerant performance, and more flexible control freedom. With these several advantages, multiphase drive systems have become a candidate for three-phase motor drive systems in electric vehicle (EV) applications. As a result, there have been a large number of researches and reports on multiphase drives in the past few years. Based on this, the purpose of this paper is to provide an overview of the multiphase motor drives (MPDs) configurations in recent years with a new perspective, and to comprehensively review, analyze, and summarize the performance advantages and disadvantages of the various MPDs configurations. The aspects elaborated also include a general introduction to multiphase motors, with six-phase configurations highlighted here due to their three-phase and multiphase characteristics, which simplify the production process. In addition, the current state of the art of MPDs used in heavy-duty electric vehicles and industrial traction is included. The paper concludes with an analysis and discussion of future trends and challenges for MPDs systems.

Conventional dc-dc boost converter has limited boost capacity, and its power device suffers high voltage stress. A novel hybrid Z-source dc-dc converter featured with high step-up capability and low device voltage stress is proposed in this article. Compared with the basic structure, the proposed topology can achieve higher voltage gain under the same duty ratio, and reduce the voltage stresses on the switch and diode under the same output condition. Moreover, the duty ratio is not limited. The detailed analysis and a comparison considering the proposed and other structures are also presented, which confirms its unique advantages. To verify the proposed converter performance, a prototype circuit with 40V-60V input voltage, 400V output voltage and 200W output power is built in the laboratory. Experiment results confirm the analysis and the boost capacity of the proposed converter.

Isolated bidirectional DC–DC converters are becoming increasingly important in various applications, particularly in the electric vehicle sector, due to their ability to achieve bidirectional power flow and their safety features. This paper aims to review the switch strategies and topologies of isolated bidirectional DC–DC converters, with a specific focus on their applications in the field of electric vehicles. From the perspective of topology, PWM-type isolated bidirectional DC–DC converters, dual active bridge converters, and resonant-type isolated bidirectional DC–DC converters constitute the three main categories of these converters. The paper further examines the traditional switch strategies of these converters and discusses how specific switch technologies, such as single-phase shift, expanding-phase shift, double-phase shift, and triple-phase shift, can enhance the overall performance of isolated bidirectional DC–DC converters. The paper meticulously examines the characteristics of each topology and control scheme, as well as their typical use cases in practical applications. Particularly, the paper delves into the applications of isolated bidirectional DC–DC converters in the electric vehicle sector and draws conclusions regarding their potential and trends in future electric vehicle technology.

Dual-active-bridge (DAB) converter can connect several ac distribution networks with different voltage levels by a common dc bus to form ac/dc hybrid distribution networks. Its reliability issue has become a hot research topic in academia and industry. In this article, the fault operation mode of DAB is analyzed in detail, and a fault diagnosis strategy based on adaptive threshold denoising for residual networks is proposed on this basis. The main module of the diagnosis algorithm consists of an improved channel attention module and threshold algorithm. The improved channel attention module improves the network’s ability to learn features by using two ways to extract different features of the fault signal separately. The threshold algorithm is embedded into the deep network as a nonlinear layer. The thresholds can be learned adaptively in the established cells, which plays a good adaptive denoising capability. Finally, by building a hardware-in-the-loop system, we compare the signal denoising ability of various methods at different signal-to-noise ratios. The experimental results demonstrate that the proposed method can accurately locate the open-circuit fault and achieve 99.82% accuracy under the original data. It is also more accurate than other methods under different signal-to-noise ratios, which verifies the correctness and effectiveness of the method.

To improve the efficiency of the dual active bridge (DAB) converter working in the low and medium power ranges, this paper proposes a new triple-phase-shift (TPS) modulation scheme based on frequency domain fundamental harmonic analysis (FDFHA) with lower root mean square (RMS) current and wider zero-voltage switching (ZVS) range. The DAB converter’s Fourier decomposition expression under TPS is generated, and the FDFHA expression is created using fundamental harmonic analysis (FHA). With the RMS current as the optimization target, the operating point with the smallest RMS current is found by solving for it using the extended global optimum condition (EGOC) that applies to the FDFHA expression. Based on this, a control strategy with a simple controller structure is established, which has excellent dynamic performance. Additionally, when comparing the proposed scheme to other optimized schemes, the results show that the proposed scheme can drastically lower the RMS current in the low and medium power ranges and achieve a wider ZVS range, notably in the low power range to enable all switches to achieve ZVS. Finally, an experimental prototype with a peak efficiency of 95.95% was built to verify the effectiveness of the proposed scheme.