This paper investigates the inverter nonlinearities in a drive system based on silicon carbide metal-oxide-semiconductor field-effect transistor (SiC-mosfets) and compares its performance with that of an equivalent silicon insulated-gate bipolar transistor (Si-IGBT) system. Initially, a novel comprehensive analytical model of the inverter voltage distortion is developed. Not only voltage drops, dead time, and output capacitance, but also switching delay times and voltage overshoot of the power devices are taken into account in the model. Such a model yields a more accurate prediction of the inverter's output voltage distortion, and is validated by experimentation. Due to inherent shortcomings of the commonly used double pulse test, the switching characteristics of both SiC-mosfets and Si-IGBTs in the pulse width modulation inverter are tested instead, such that the actual performances of the SiC and Si devices in the motor drive system are examined. Then, the switching performance is incorporated into the physical model to quantify the distorted voltages of both the SiC-based and Si-based systems. The results show that, despite its existing nonlinearities, the SiC-based drive has lower voltage distortion compared to the conventional Si-based drive as a result of its shorter switching times and smaller voltage drop, as well as a higher efficiency. Finally, the overriding operational advantages of the SiC-based drive over its Si-based counterpart is fully demonstrated by comprehensive performance comparisons.

A novel nondissipative two-stage equalization circuit topology based on the traditional buck–boost circuit is proposed to achieve balancing of series-connected lithium-ion battery packs with higher efficiency and less cost, considering the background on international energy issues and the development trend of battery balancing. The proposed topology achieves high efficient balancing of lithium-ion battery packs without adding additional devices. Detailed illustration of the presented topology, the operation principles and control approaches are described with visualized figures in this article. Then, under the condition of accurate modeling of the lithium-ion battery, relying on the experimental data, the simulation block is built based on MATLAB. Furthermore, the prototype of the proposed topology was designed and manufactured. The effectiveness of the proposed topology is verified by both the simulation and experiment.

Internet-of-Things devices and next-generation DC power distribution systems require a power supply to provide multiple output voltages and dispatch input power from multiple energy sources. Using multi-input multi-output DC/DC converters may benefit such power supplies and systems in reducing their count of electronic components, complexity, and power losses. This express for the first time presents a generalized synthesis methodology to derive multi-input multi-output converters without intermediate energy buffer stages, based on basic power converter cells. The rigorous principles of combining these circuitry cells are proposed. Two design examples are shown to demonstrate the proposed methodology.

A novel topology based on linear power amplifiers (PAs) and real-time sinusoidal voltage-adjustment power supply systems (RTSPSs) for a permanent magnet synchronous motor (PMSM) drive system is proposed in this article. Here, PAs are applied to achieve high-precision motor drive control and minimize the motor torque ripple and harmonic loss caused by nonlinearities of the inverter in traditional space vector pulsewidth modulation. Meanwhile, in order to improve the conversion efficiency of PAs, the traditional dc power supply system of PAs is replaced by the RTSPSs, which is based on the wide-band-gap devices. The experimental results show that the efficiency of PAs in the motor system is increased from 58.88% to 79.25% and the fluctuation of the motor speed at a given speed of 2 r/min is reduced from 27 to 0.5 r/min.