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An accurate mover position is important for a planar switched reluctance motor (PSRM) to achieve precision positioning; however, position sensors are susceptible to the influence from harsh conditions and are relatively expensive. In this article, an assistant-mover-based position estimation method is proposed to increase the reliability and reduce the cost of a PSRM system. The method is based on a mapping relationship between the flux density and position of the assistant mover. First, the configuration of the assistant movers is presented. Then, an analytical model of the flux density of the assistant mover is developed by using an equivalent magnetic circuit method. Based on the analytical model, the parameters of the assistant mover are determined. According to the flux density characteristics, a position estimation algorithm with the advantages of not requiring previous experimental data, simple computation, and small memory consumption is developed. Moreover, considering the deviation in the characteristics of each assistant mover, a compensation strategy is proposed to obtain better position estimation accuracy. Finally, the proposed method is implemented with the PSRM system. The effectiveness of the proposed position estimation method is verified experimentally.

This paper proposes a drive circuit for single-phase brushless direct current (BLDC) fan motors to reduce their acoustic noise. First, the torque ripple of a single-phase BLDC motor is analysed theoretically. Then, a drive circuit that is capable of regulating the DC-link voltage during commutation to weaken the negative effect of current lag is proposed to reduce the acoustic noise of single-phase BLDC fan motors. Furthermore, the characteristics of the proposed drive circuit are discussed theoretically using a deduced analytical model of the proposed drive circuit. Additionally, simulations based on the finite element method and experiments are performed. The torque ripple and acoustic noise generated by the conventional and proposed drive circuits are compared. The simulation results show that the torque ripple is reduced by 16.1% when the proposed drive circuit is used, and the experimental results illustrate that the acoustic noise generated by the second harmonic of the torque ripple is reduced by 7.3%. Ultimately, the effectiveness of the proposed drive circuit is verified.

In this paper, a planar flux-switching permanent magnet (PFSPM) motor, which is the first of its kind for planar motors, is designed and analyzed. First, the topology structure, modeling, and operating principle of the PFSPM motor are clarified. Then, the initial dimension of the PFSPM motor is determined in terms of its topology structure. Based on the initial dimension, the width of the iron core and the length of the permanent magnet are optimized to increase the thrust force and reduce the cogging force. In addition, a 3-D finite-element analysis (FEA) is performed. Finally, the experiments are conducted based on a developed prototype of the PFSPM motor with the optimized dimension. The results demonstrate that the thrust force is increased by 21%, and the cogging force is reduced by 56% via FEA; the thrust force of the experimental measurement is largely consistent with that determined via the FEA.

The hydrocarbon charge history of the Paleogene in the northern Dongpu Depression was analyzed in detail based on a comprehensive analysis of the generation and expulsion history of the major hydrocarbon source rocks, fluorescence microscopic features and fluid inclusion petrography. There were two main stages of hydrocarbon generation and expulsion of oil from the major hydrocarbon source rocks. The first stage was the main hydrocarbon expulsion stage. The fluorescence microscopic features also indicated two stages of hydrocarbon accumulation. Carbonaceous bitumen, asphaltene bitumen and colloidal bitumen reflected an early hydrocarbon charge, whereas the oil bitumen reflected a second hydrocarbon charge. Hydrocarbon inclusions also indicate two distinct charges according to the diagenetic evolution sequence, inclusion petrography features combined with the homogenization temperature and reservoir burial history analysis. According to these comprehensive analysis results, the hydrocarbon charge history of the Paleogene reservoir in the northern Dongpu Depression was divided into two phases. The first phase was from the late Dongying depositional period of the Oligocene to the early uplift stages of the late Paleogene. The second phase was from the late Minghuazhen period of the Pliocene to the Quaternary. Reservoirs formed during the first period were widely distributed covering the entire area. In contrast, reservoirs formed during the second period were mainly distributed near the hydrocarbon generation sags. Vertically, it was characterized by a single phase in the upper layers and two phases in the lower layers of the Paleogene.

This paper proposes a multi-segment sliding mode (MSSMC) method for the planar switched reluctance motor (PSRM) developed in the laboratory to achieve precision positioning. The mechanical structure, the mathematic model and the control strategy are first given. Based on the mathematic model, the MSSMC strategy is then designed, which consists of an acceleration segment, a deceleration segment, and a positioning segment. Additionally, the stability analysis is discussed for the closed-loop system with the designed MSSMC strategy. Simulation is carried out based on MATLAB/Simulink. Compared to the conventional sliding mode control (SMC), the MSSMC is capable of weakening and better steady-state and dynamic performances were achieved. The effectiveness of the proposed MSSMC method is verified through simulation.

This paper proposes a sensorless initial mover position detection method with bootstrap circuit for the planar switched reluctance motor (PSRM). The mechanical structure and mathematical model of the PSRM is first presented. The sensorless initial mover position detection method is then developed based on bootstrap circuit. For this method, the voltage and the peak time of voltage are measured by charging a bootstrap capacitor of each phase of the PSRM; the position range and the inductance are calculated theoretically according to the peak time; the initial position can be calculated theoretically in terms of the built inductance model and position range. Furthermore, simulation is carried out base on ANSYS Maxwell. Simulation results demonstrate that the relative error between the detected position and the real position is less than 3% with the proposed method; the effectiveness of the proposed method is verified.

This paper presents a DSP-based sliding mode controller of the planar switched reluctance motor (PSRM) for precision positioning applications. The mechanical structure, control scheme, and the design of sliding mode controller are presented and analyzed, respectively. The DSP-based sliding mode controller is implemented for the PSRM experimentally. The steady-state positioning errors of x- and y-axes are 0.016 and 0.029 mm, respectively. The effectiveness of the DSP-based sliding mode controller for the PSRM is verified through the experimental results.