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In the square-wave voltage signal injection sensorless drive of the interior permanent-magnet synchronous machine, the injection voltage can be distorted by the inverter nonlinearity effects especially when the injection voltage is low. If that happens, a high-frequency (HF) current signal which contains the rotor position information could be also distorted, which directly leads to an error in the position estimation. This paper analyzes the effects of the inverter nonlinearity on injection voltage, on induced current ripple, and on the position estimation performance in sequence and proposes a voltage injection method to minimize the impact of the inverter nonlinearity by the regulation of the HF current ripple. By simulations and experiments, the performance of the proposed method has been verified. The experimental results show 19.7% reduction of position estimation error under 15% of rated voltage signal injection without increasing the current ripple at a certain operating condition. Moreover, the performance of position estimation is kept uniform regardless of the loading condition. [ABSTRACT FROM AUTHOR]

Multiwalled nanotube (MWNT)/silicone composites having segregated MWNT network and micro-void structure were developed for wearable thermotherapy application. The nano-composites could be quickly fabricated from instant evaporation of aqueous medium during spray coating process. Fast electric heating behavior (4.8 °C/s) was demonstrated, in comparison with that (1.4 °C/s) of conventional silicone rubber composites having no void. Long-term stability was also verified with thermal aging and thermal cycling tests up to 100 h. [ABSTRACT FROM AUTHOR]

Highly conducting carbon nanotubes (CNTs)/polydimethylsiloxane (PDMS) composite with a low concentration (5.7 vol.%) has been shown to be applicable in a highly controllable electric heating element. Due to a high shear-processing technique for mixing CNTs into an uncured PDMS matrix, the CNT/PDMS composites have a fairly uniform dispersion and no agglomeration of CNTs. The percolation threshold of the prepared CNT/PDMS composite is achieved \sim0.03~vol.\%, which is one of the lowest values previously reported in the literature. The fabricated CNT/PDMS composites can be quickly heated from room temperature to 200^\circC within 30 s by applying a DC voltage of 12 V. In addition, the CNT/PDMS composite show good thermal stability and repeatability during a long-term heating test. Our proposed CNT/PDMS composites could be used as a basis for light-weight and flexible heating-unit applications. [ABSTRACT FROM AUTHOR]