Position Estimation of a Two-Phase Switched Reluctance Motor at Standstill

In this paper, a sensorless position detection method of a two-phase switched reluctance motor (SRM) at standstill is proposed based on the voltage pulse injection method. Due to the torque dead zone and the lack of starting capability in the two-phase SRM, a rotor with a stepped structure is adopted to ensure continuous torque generation. The inductance characteristics of the asymmetric SRM are analyzed, and the region of the rotor position is categorized into linear regions and nonlinear regions with several key rotor positions and threshold values of self-inductance. A simple analytical model of the phase self-inductance profile of the asymmetric rotor SRM is proposed, which only requires a few linear equations, to replace the conventional look-up table. A pulse injection-based position estimation method is proposed based on the aforementioned analytical model. Short voltage pulses are injected into both phases at the same time to determine the position where the rotor is actually located at standstill. The proposed position detection method is simple and requires no extra circuitry. The simulation results are given and show the proposed estimation method can acquire a precise rotor position accurately at a standstill condition.

Research on Analysis and Classification of Vulnerability of Electromagnetic Pulse with a STM32 Single-Chip Microcomputer

With the continuous development of information technology, the performance of the entire traditional electrical system is gradually optimized. Nowadays, the single-chip technology is an important part of the traditional electrical system because it determines the operating quality of the entire traditional system. However, due to the electromagnetic pulse, the single-chip microcomputer system may be interfered with malfunction or damage, which seriously affects its performance. Therefore, to investigate the impact of an electromagnetic pulse on a single-chip microcomputer system, in this research work, we have used a STM32 single-chip microcomputer as the research object by setting up multiple sets of STM32 single-chip microcomputer serial communication systems. Besides, we have conducted an electromagnetic pulse vulnerability experiment using the inductive coupling inject method which has improved the antielectromagnetic pulse capacity of the STM32 single-chip serial communication system. The experimental results show that the damage threshold of the single-chip microcomputer with positive pulse injection is greater than the negative pulse injection, which indicates that the serial communication system of the STM32 single-chip microcomputer is more sensitive to the negative pulse injection. Moreover, this research work is of great significance to evaluate more accurately the viability and anti-interference capability of a single-chip microcomputer system under the action of electromagnetic pulse.

Experimental demonstration of NO reduction and ammonia slip for diesel engine SCR system

This paper aims to investigate the characteristics of selective catalytic reduction(SCR) in a V2O5-WO3/TiO2 catalyst by studying the key parameter, and obtain the control method of NH3 injection under sample test bench. Four parameters are defined and adopted to represent the NO-NH3 reaction characteristics. The effect of NH3/NO ratio(NSR), catalyst temperature and NH3 injection period on NO conversion efficiency and NH3 slip was investigated. The correlation between NH3 slip and ammonia saturation storage level was studied. The experimental results show that the ammonia saturation storage level has great effects on NO reduction and NH3 slip. The NO conversion efficiency and NH3 slip strongly depends on the ammonia saturation storage level. Under such condition, the NO conversion efficiency is best when the ammonia saturation storage level is 68.2%~73%, until the value reach to 75% before the NH3 slip. Pulse injection can improve the NO conversion efficiency and NH3 slip. The period of pulse injection has few influence on the mean value of NO at the outlet, however, it affects the peak value of NO and NH3 slip. Using varied period pulse injection can further improve NO conversion efficiency and restrain NH3 slip. The outlet NO is able to be reduced by adopting suitable NH3 pulse injection interval.