To improve the degree of intelligence of a substation and cut down the cost of inspection, substation inspection robots instead of the human labor are employed to perform daily inspections. However, the battery life greatly limits the work of inspection robots, so the full-time inspection cannot be realized. To solve this problem, a dynamic wireless charging method is used to charge the robots, so that the robots can perform inspections while charging and realize full-time inspection. In this paper, the relationship between coil mutual inductance and system efficiency is analyzed at first. Then, aimed at the segmented primary coil rails used in the dynamic wireless charging system, a soft-switching method for rails is put forward to reduce the inrush current during the switching process, thus protecting the circuit components. Finally, the influence of coil mutual inductance on the system efficiency was verified by experimental results, and the feasibility and effectiveness of the soft-switching method for rails was also proved.

For a traditional Boost power factor correction (PFC) converter, its output voltage must be greater than its input voltage, which limits its applications in light emitting diode (LED) drivers to a certain degree. Meanwhile, due to the existence of a rectifier bridge at the input end of the traditional LED driver, the improvement of its efficiency is also confined. In this paper, a bridgeless Boost LED driver based on passive current balancing is proposed, which is based on the topology of a resonant Boost PFC converter. With the introduction of a resonant capacitive current-balancing network, the output current of each LED string can be balanced. In addition, the elimination of the rectifier bridge further improves the system efficiency. Finally, a 140 W prototype with a peak efficiency of 93.64% was built, and experimental results verified the correctness and feasibility of theoretical analysis.

A flux-weakening control method for permanent magnet synchronous motor (PMSM) used in electric vehicles is put forward on the basis of current prediction to improve the dynamic performance in the flux-weakening region of PMSM. The voltage boundary problem in the flux-weakening region is analyzed in detail, and the stability problem under different voltage selection criteria is also introduced. On this basis, a dynamic overmodulation strategy considering the stability and dynamic characteristics is proposed. Furthermore, a model-based predictive current control algorithm is investigated, in which the advantages of fast dynamic response and manageable constraints help to improve the dynamic performance in the flux-weakening region while guaranteeing the stability. Finally, the effectiveness of the proposed algorithm was verified on a simulation platform and an experimental platform, respectively.

The silicon carbide (SiC) device is considered as a semiconductor device with high temperature resistance, and a careful study on its loss and heat dissipation is required when it is applied to high-power-density and high-temperature scenarios. The maximum current conduction capability of SiC MOSFET power module at high temperature is studied, and the relationship between electrical performance and heat dissipation is taken into account. Based on an electro-thermal coupling model of SiC MOSFET device and a heat dissipation model of the cooling system, the mechanism of thermal runaway process is analyzed. A co-simulation is conducted to determine the current conduction capability of one SiC power module at high temperature, and the simulation error with respect to the experimental result is about 4%, which verifies the effectiveness of the proposed method.

Building a complete spacecraft electrical power and distribution standard system is an important tool for improving the design of spacecraft electrical power and distribution system and ensuring the safety and reliability of satellite energy. In this paper, the electrical power and distribution standard systems published by European Cooperation for Space Standardization (ECSS), National Aeronautics and Space Administration (NASA), Japan Aerospace Exploration Agency (JAXA), International Standard Organization (ISO) and American Institute of Aeronautics and Astronautics (A-IAA) were investigated. The focuses of their respective standard specialties were analyzed, the corresponding content was discussed, and the standard systems of various organizations were summarized. Combined with the actual situation in China, the suggestion and reference for the spacecraft electrical power and distribution standard system are put forward.

Aimed at the problem that the performance of dielectric barrier discharge (DBD) load cannot be fully utilized by the common load resonant-type power supply with continuous waveform and the deficiency that the topologies of existing pulsed power supplies are complicated, a power supply with unipolar forward pulse is proposed in this paper, which consists of one power switch, two diodes and one coupled inductor. Through the analysis of its working modes, it is shown that this power supply can provide a fast-rising pulse voltage for DBD load. In addition, the power switch operates in a soft-switching state. Simulation and experimental results verified the feasibility of the proposed power supply, indicating that it can provide certain reference for the upgrade of the existing power supplies for DBD load.

In response to the high-voltage steep pulse application demands such as those in the biomedical industry, a series and parallel high-voltage steep pulse generator circuit based on solid-state switches is designed, and a novel pulse steepening method is proposed by combining the timing control technology. The key to pulse steepening, the system's working process and the main points of design are analyzed theoretically. This method can better reduce the influences of stray parameters, wiring inductance and wire inductance on the switching speed after adding the switching tubes. An experiment was carried out with a 2 kV high-voltage DC power supply and a load resistance of 110 Ω, and experimental results show that the rising edge of load pulse signal was 50 ns approximately, the falling edge was 70 ns approximately, and the output current amplitude was 18 A approximately. The half-height width of the minimum pulse width signal was 100 ns, and the system's minimum resolution was 5 ns, which can realize a flexible adjustment of 5 ns pulse width step by step. The maximum pulse width was related to the energy storage capacitor.

The existing power amplifier cannot strike a balance among aspects such as its output efficiency, output power and linearity. To solve this problem, on the basis of a three-level cascade amplification method, a kind of AB class RF power amplifier based on a power synthesizer and a power splitter is proposed. Aimed at the problems of linearity and gain, the band-pass matching and T-network matching techniques are used to optimize the design of the pre-driver circuit. The problem that the output power of the final amplifier is too large is solved by using the power synthesis technique, and the stability and efficiency of the power amplifier are guaranteed. To prevent the temperature of the power amplifier from being too high, the thermal characteristics of the power amplifier cavity are analyzed. The highest temperature is 81°C, which can make the power amplifier get a good cooling. At room temperature, the RF power amplifier has an output power of 47 dBm, an amplification gain of 42 dB and a maximum power added efficiency of more than 45% at a central frequency point of 2.45 GHz. The test results were close to simulation results, indicating that the research in this paper can provide some guidance for the subsequent research and design of amplifiers.

Silicon carbide (SiC) switching devices are widely applied in DC/DC converters owing to their faster switching speed and higher operating frequency. However, the high working frequency of SiC devices will result in strong electromagnetic radiation interference. To optimize the internal structure of DC/DC converter and achieve a higher power density, an optimization method for the electromagnetic radiation interference of SiC DC/DC converter is proposed. First, the characteristics of the converter's electromagnetic radiation interference source are analyzed, and a space electromagnetic radiation model is established according to the topology of DC/DC circuit. Then, based on the electromagnetic radiation model and simulated annealing algorithm, the low electromagnetic radiation optimization is carried out for the layout of components within the DC/DC converter. The optimized layout scheme reduces the length of high-frequency wire by 60.2%. Finally, the three-dimensional finite element simulation is carried out, and it is verified that the proposed method can optimize the circuit layout of SiC DC/DC converter and reduce the electric field intensity produced on the sensitive circuit by two orders of magnitude.

The fast on-off switching signal is the main cause of electromagnetic interference (EMI). At present, the research on EMI suppression by chaos mainly focuses on the suppression of conducted EMI by integer-order chaos. On this basis, the suppression by fractional-order chaos on radiated EMI and the selection of optimal order are studied in this paper. First, through the analysis of spectrum characteristics of fractional-order Lorenz and Lyapunov exponent spectrum, 1.8-order Lorenz signal is selected as the best spread spectrum series. Second, based on the principle of EMI suppression technology with variable switching frequency, Lorenz chaotic spread spectrum PWM signals with fixed frequency, integer-order, 2.7-order and 1.8-order are implemented in an STM32 single chip microcomputer. A near-field radiation experiment was carried out on a 5 W flyback converter, which proved that the 1.8-order Lorenz signal had the strongest suppression effect on the near-field magnetic field radiation. Finally, experimental results showed that the prototype's overall efficiency was about 2% different when it was under the fractional-order Lorenz Chaos PWM control and constant-frequency PWM control, respectively, which verified the superiority of the fractional-order chaotic PWM in radiated EMI suppression performance.