Achieving superelasticity in additively manufactured Ni-lean NiTi by crystallographic design

Superelastic metallic materials possessing large recoverable strains are widely used in automotive, aerospace and energy conversion industries. Superelastic materials working at high temperatures and with a wide temperature range are increasingly required for demanding applications. Until recently, high-temperature superelasticity has only...

Effect of heat treatment on microstructure and functional properties of additively manufactured NiTi shape memory alloys

Additive manufacturing of NiTi shape memory alloys has attracted attention in recent years, due to design flexibility and feasibility to achieve four-dimensional (4D) function response. To obtain customized 4D functional responses in NiTi structures, tailorable phase transformation temperatures and stress windows as well as one-way or two-way...

Healing cracks in additively manufactured NiTi shape memory alloys

The pursuit of enhancing NiTi superelasticity through laser powder bed fusion (L-PBF) and [001] texture creation poses a challenge due to increased susceptibility to hot cracking in the resulting microstructure with columnar grains. This limitation restricts NiTi's application and contributes to material waste. To overcome this, we introduce...

Compensation Method of Position Estimation Error for High-Speed Surface-Mounted PMSM Drives Based on Robust Inductance Estimation

This article proposes a compensation method of position estimation error for high-speed surface-mounted permanent magnet synchronous motors based on robust inductance estimation. The proposed method relies on the variation of the estimated δ-axis back back-electromotive force when a small current is injected into the γ axis. The inductance...

Discrete-Time Dynamic-Decoupled Current Control for LCL-Equipped High-Speed Permanent Magnet Synchronous Machines

This article proposes a discrete-time dynamic-decoupled current controller for an LCL-equipped high-speed permanent magnet synchronous machine with only the motor currents measured. The controller is designed in the synchronous coordinate based on a complex z-domain transfer function. The main contribution of the proposed current controller...

Dynamic-Decoupled Active Damping Control Method for Improving Current Transient Behavior of LCL-Equipped High-Speed PMSMs

In this article, a novel dynamic-decoupled active damping current controller is proposed for an LCL-equipped high-speed permanent magnet synchronous machine. Compared with the conventional stationary current-control method for the LCL-type system, the proposed method is established in the synchronous rotating frame for improving the current...

A General Single-Sensor Damping Framework for LCL-Equipped High-Speed PMSM Drives

This letter proposes a general single-sensor active damping framework for LCL-equipped high-speed permanent magnet synchronous machines. By the proposed method, arbitrary damping assignment and stability for the LCL resonance within the Nyquist frequency are achieved with only the inverter-current feedback or motor-current feedback. Moreover,...

Three-Mode Variable-Frequency ZVS Modulation for Four-Switch Buck+Boost Converters With Ultra-high Efficiency

This article introduces a three-mode variable-frequency zero-voltage switching (ZVS) modulation method for the four-switch buck+boost converter. This method makes this circuit concept well suited for applications, such as wireless power charging of electric vehicles, where this circuit operates as a power buffer between the resonant converter...

Rotor Eddy Current Loss Reduction with Permeable Retaining Sleeve for Permanent Magnet Synchronous Machine

This article presents a new rotor design to reduce rotor eddy current loss of a high-speed permanent magnet synchronous machine for flywheel energy storage system. Instead of using common nonmagnetic sleeves, the new rotor incorporates permeable retaining sleeves (PRSs) to fix permanent magnets on the rotor hub. The PRSs are made of permalloy...

Lake seasonality across the Tibetan Plateau and their varying relationship with regional mass changes and local hydrology

The recent growth and deepening of inland lakes in the Tibetan Plateau (TP) may be a salient indicator of the consequences of climate change. The seasonal dynamics of these lakes is poorly understood despite this being potentially crucial for disentangling contributions from glacier melt and precipitation, which are all sensitive to climate,...