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This article provides a comprehensive overview of state-of-the-art techniques for detecting and diagnosing stator winding inter-turn short faults (ITSFs) in permanent-magnet synchronous motors (PMSMs) for electric vehicles (EVs). The review focuses on the following three main categories of diagnostic approaches: motor model-based, signal processing-based, and artificial intelligence (AI)-based fault detection and diagnosis methods. Motor model-based methods utilize motor state estimation and motor parameter estimation as the primary strategies for ITSF diagnosis. Signal processing-based techniques extract fault signatures from motor measured data across time, frequency, or time-frequency domains. In contrast, AI-based methods automatically extract higher-order fault signatures from large volumes of preprocessed data, thereby enhancing the effectiveness of fault diagnosis. The strengths and limitations of each approach are thoroughly examined, providing valuable insights into the advancements in ITSF detection and diagnosis techniques for PMSMs in EV applications. The emphasis is placed on the application of signal processing methods and deep learning techniques in the diagnosis of ITSF in PMSMs in EV applications. [ABSTRACT FROM AUTHOR]

In distributed generation systems, converters play a vital role and DC/DC converter technology is constantly being promoted with the increasing demand for electrical equipment in various industries. A cascaded topology of DC/DC converter has been proposed in this paper, named three‐level Buck‐LLC(TL‐BLLC) converter. In the proposed TL‐BLLC, Buck and LLC circuit are cascaded by a switch and a diode, so that the input voltage of the LLC can be adjusted to three levels. The stability of the output voltage of the whole system depends on the three‐level weight, so the LLC works at fixed frequency, which simplifies the control and ensures the efficiency. At the same time, compared with the traditional cascaded Buck‐LLC, this structure can reduce the processing power and reduce the size of passive elements of the previous Buck. Finally, a 980 W experimental prototype was established and the results of the experiment verified the correctness of the theoretical analysis. [ABSTRACT FROM AUTHOR]

A large-aperture silicon carbide (SiC) aspheric mirror has the advantages of being light weight and having a high specific stiffness, which is the key component of a space optical system. However, SiC has the characteristics of high hardness and multi-component, which makes it difficult to realize efficient, high-precision, and low-defect processing. To solve this problem, a novel process chain combining ultra-precision shaping based on parallel grinding, rapid polishing with central fluid supply, and magnetorheological finishing (MRF) is proposed in this paper. The key technologies include the passivation and life prediction of the wheel in SiC ultra-precision grinding (UPG), the generation and suppression mechanism of pit defects on the SiC surface, deterministic and ultra-smooth polishing by MRF, and compensation interference detection of the high-order aspheric surface by a computer-generated hologram (CGH). The verification experiment was conducted on a Ø460 mm SiC aspheric mirror, whose initial surface shape error was 4.15 μm in peak-to-valley (PV) and a root-mean-square roughness (Rq) of 44.56 nm. After conducting the proposed process chain, a surface error of RMS 7.42 nm and a Rq of 0.33 nm were successfully obtained. Moreover, the whole processing cycle is only about 216 h, which sheds light on the mass production of large-aperture silicon carbide aspheric mirrors. [ABSTRACT FROM AUTHOR]

In this paper, a technique of variable-turns-ratio high-frequency link inverter is proposed to provide a simple method to achieve multi-level outputs for the isolated single-stage high-frequency link inverters. By dynamically adjusting the turns ratio of transformer, five-level (±2, ±1, and 0) outputs can be achieved to improve the current quality. The single transformer, compared with the existing two-level high-frequency link inverter, is employed in the structure and only a few auxiliary devices are added, where the added circuit operates at low frequency and the power density is refined. Based on this technique, the single-stage active clamped forward grid-connected inverter with variable turns ratio is taken as an example to better illustrate the analysis process and a 1000-W prototype is designed and established to evaluate the output performance. The conducted simulation results and prototype tests verify the feasibility of the proposed single-stage variable-turns-ratio high-frequency link grid-connected inverter. [ABSTRACT FROM AUTHOR]

Switching-linear hybrid envelope tracking (SLH ET) power supplies can achieve both high efficiency and high bandwidth. However, the switching frequency is often required to be far higher than or at least equal to the envelope bandwidth. With the modulation methods advance, the increasing envelope bandwidth may lead to a too high switching frequency to implement. This paper proposes an SLH ET power supply, consisting of a multilevel converter and a linear amplifier connected in series. Based on the multicell configuration of the multilevel converter, a pulse edge independent distribution method is proposed, which can break the control pulses for the multilevel converter into independent rising and falling edges, and rebuild them with new sequences. It can not only reduce the switching frequency to 1/n (n ∊ N) of the envelope bandwidth but also extend the pulsewidths to provide a more reliable and effective driving for high bandwidth applications. A prototype for 2 MHz sine-wave tracking, with 7–27-V output voltage and 90-W peak output power, is fabricated and tested. It is also verified by a 5- and a 10-MHz bandwidth communication envelope. The experimental results validate the proposed method. [ABSTRACT FROM AUTHOR]

Transformerless photovoltaic (PV) inverters are more widely adopted due to high efficiency, low cost, and light weight, etc. Many novel topologies and their corresponding modulation methods have been proposed, verified, and put into use, solely focusing on active power injection without leakage current issues. However, some new grid codes require PV inverters to have the ability of injecting reactive power into the utility for grid support. In order to map the challenge, an improved hybrid modulation method is proposed and evaluated for one nonisolated H6 topology as an example. With only simple modification for switching patterns and phase shift for current reference, the variable reactive power generation ability with zero crossing distortion is achieved, while the common mode voltage is also eliminated. The operation modes with the improved hybrid modulation approach are presented in detail and some design considerations are also provided. Extensive results from a 4-kVA prototype along with the SMPLIS simulation verify the proposed hybrid modulation method. [ABSTRACT FROM AUTHOR]

A novel interleaved dual buck full-bridge three-level inverter (IDBFTI) is proposed for the grid-connected system in this paper. It retains the advantages of interleaved parallel technology for inverter as follows: reducing the output ripple current and the total harmonic distortion of the output current, increasing the power density of system, and reducing the current stress and thermal stress of power devices. Besides, it can solve the problem of zero sequence circulation current (ZSCC) in interleaved inverter system by the circuit structure, and it also has the advantages of no shoot-through problem, no reverse recovery of the body diode, and three-level output. The interleaved inverter circuits share two power-frequency switches, which are resized for each specific application, and it is easier to extend the system by improving current capability of the two switches. The working principle of this system is introduced in detail, and a 2-kW experimental prototype has been established and tested. Test results verify the principle and the excellent performance of IDBFTI. [ABSTRACT FROM PUBLISHER]

A new single inductor dual buck full-bridge inverter is proposed in this paper. The inverter is improved on the basis of a dual buck inverter, and it retains the advantage of a no reverse recovery of body diode. The dc voltage utilization rate can be increased by adopting the voltage commutation bridge instead of the voltage-dividing capacitors in the inverter. In addition, comparing with other dual buck inverters, the inverter has just one filter inductor, which can make the volume and weight of the system decreased observably and improve the integration. The controlling method, combining the high- and low-frequency modulation, is adopted to weaken the complexity of control and improve the reliability and stability of the system. The operating principle, characteristic analysis, simulation and experiment are provided in this paper. A 1-kW prototype is established and tested, and the results of simulation and experiment verify the correctness of the theoretical analysis. [ABSTRACT FROM PUBLISHER]

The main contribution of this paper is the derivation rules summarized from existing high-performance inverters with H6-type configuration, which makes novel topologies possible. In addition, a novel high-efficiency single-phase transformerless photovoltaic inverter with hybrid modulation method is also proposed and evaluated as an example. Without input split capacitors, common-mode voltage and leakage current issues in a nonisolated system with H6-type configuration are eliminated, and the feature of a three-level output voltage in the inverter bridge's middle point helps inductors and power quality optimization. The detailed operation principles with hybrid modulation strategy combined with unipolar and bipolar pulsewidth modulation schemes are presented. Experimental results of a 2200VA prototype verify the proposed topology with hybrid modulation method. [ABSTRACT FROM PUBLISHER]