The influence of concurrent Zn diffusion on the interdiffusion in a Ga_x In_1−x As_y P_1−y ‐InP heterostructure (x=0.28, y=0.61) was investigated using Auger electron spectroscopy and secondary‐ion mass spectrometry. The measured profiles showed that the Zn diffusion (600 °C, 1–4 h) predominantly enhanced the cation (In‐Ga) interdiffusion. The result could not be interpreted by the Zn‐vacancy complex model. Under conditions of a group V overpressure, our results suggest that cation interstitials may control both the rate of Zn diffusion and the mixing of the group III sublattices in the InP‐based alloy system.

A quasi-resonant passive snubber for the conventional dc-dc step-down converter is proposed. The snubber uses six passive components to achieve a zero-current turn-on and zero-voltage turn-off of the switch, and to suppress the reverse recovery current of diode. At input voltage of 200 V, output voltage of 100 V, output power of 300 W, and switching frequency of 190 kHz, the snubber increased the power conversion efficiency η _e by 2.8% and stabilized the temperature of MOSFET switch at ~68 °C. The snubber worked well for both MOSFET and insulated gate bipolar transistor (IGBT) switches without increasing the voltage stress. These experimental results show that the proposed snubber is very helpful for improving η _e of a dc-dc step-down converter that operates at a high frequency.

This paper presents a control method that can prevent audible noise generation in an LLC resonant half-bridge dc-dc converter at a light load condition, while achieving the same input voltage range and power conversion efficiency $\eta_e$ as the burst-control method that generates an audible noise. The proposed method reduces switching and conduction losses at light load by skipping several pairs of switch-control pulses, while varying the switching frequency less than the normal-control method does. This skip-control method enables the LLC resonant converter to have a large magnetizing inductance, and to have high $\eta_e$ over a wide range of load variation. At an input voltage of 385 V, an output voltage of 24 V, and a resonant frequency of 180 kHz, the proposed method achieved $\eta_e\geq 85.46\%$ for an output power range of $7.2 \sim 360 W$; the highest $\eta_e$ was 96.08% at $P_o= 336$ W.

In this work, a new active balancing circuit is proposed. This circuit consists of a cell-access network and an energy-transfer network. The cell-access network requires 2n + 6 switches, where n is the number of cells, and creates an energy-transfer path between unbalanced cells and the energy-transfer network. The energy-transfer network has double energy carriers and simultaneously implements cell-to-pack and pack-to-cell balancing operations without overlapping. As a result, a high power rate and fast balancing operation can be achieved by using two energy carriers in a single balancing circuit. The prototype of a proposed balancing circuit was built for six cells and then tested under various conditions; all cells in the state of charge (SOC) region of 70% to 80% were equalized after 93 min, and one charging/discharging period in the SOC region of 10% to 90% was increased by 8.58% compared to the non-balancing operation. These results show that the proposed circuit is a good way to balance charges among batteries in a battery pack.