Abstract: An exhaust manifold includes: an inlet portion which collects exhaust gas discharged through a first to a fourth exhaust ports; an outlet portion discharging the exhaust gas; and a tube portion connecting the inlet and the outlet portions. The inlet portion comprises: a first inlet portion one end of which communicates with the first and the second exhaust ports; and a second inlet portion one end of which communicates with the third and the fourth exhaust ports. Since the inlet portion is provided as two considering the combustion sequence, the productability and the economic feasibility can be enhanced, and the surrounding space can be enlarged to enhance the workability, and a simple exterior appearance can be obtained, and interference between exhaust gases can be effectively prevented, and since the size of the exhaust manifold can be increased, an engine load can be reduced to improve the fuel mileage.

Abstract: There are provided a dielectric composition and a preparation method thereof, the dielectric composition including: a first perovskite powder for a core represented by ABO3: and a second perovskite powder for a shell represented by ABO3, having an average particle diameter corresponding to ? to 1/10 of an average particle diameter of the first perovskite powder, and included in an amount of 1 to 70 parts by weight with respect to 100 parts by weight of the first perovskite powder, wherein particles of the second perovskite powder have pores having a volume fraction of 3 to 50 vol % therein. According to the present invention, there are provided a dielectric composition having excellent dielectric characteristics and electrical characteristics, and a preparation method thereof.

Abstract: An exhaust manifold includes: an inlet portion which collects exhaust gas discharged through a first to a fourth exhaust ports; an outlet portion discharging the exhaust gas; and a tube portion connecting the inlet and the outlet portions. The inlet portion comprises: a first inlet portion one end of which communicates with the first and the second exhaust ports; and a second inlet portion one end of which communicates with the third and the fourth exhaust ports. Since the inlet portion is provided as two considering the combustion sequence, the productability and the economic feasibility can be enhanced, and the surrounding space can be enlarged to enhance the workability, and a simple exterior appearance can be obtained, and interference between exhaust gases can be effectively prevented, and since the size of the exhaust manifold can be increased, an engine load can be reduced to improve the fuel mileage.

Abstract: The present invention provides a position sensorless control method of a high performance permanent magnet synchronous motor during emergency operation, which can accurately detect a magnetic pole position of the synchronous motor based on a position sensorless vector control using an adaptive observer configured based on a permanent magnet synchronous motor model.

Abstract: The present invention provides a position sensorless control method of a high performance permanent magnet synchronous motor during emergency operation, which can accurately detect a magnetic pole position of the synchronous motor based on a position sensorless vector control using an adaptive observer configured based on a permanent magnet synchronous motor model.

Abstract: Disclosed is a method for controlling a voltage of a DC link for an electric vehicle, which can reduce a capacitance of the DC link interposed between an inverter and a DC/DC converter. The method for controlling the voltage of the DC link in a power system of a vehicle including a battery, a DC/DC converter, the DC link, an inverter, a motor, and a control part controlling the DC/DC converter and the inverter includes the steps of installing a compensator in a control loop of the control part such that a DC link current of the DC/DC converter follows a DC link current of the inverter, calculating a predetermined compensation term based on information of the motor inputted into the compensator, and applying the compensation term to a voltage node in the control loop of the control part in the compensator.

Abstract: A vector-controlled, dual inverter system for a three-phase induction motor is disclosed. The inverter system comprises a first inverter system which is connected to one end of three phase windings of a stator and performs compensation of a back electromotive force; and a second inverter system which is connected to the other end of the three windings of the stator and performs reactive power compensation.

Abstract: A vector-controlled, dual inverter system for a three-phase induction motor is disclosed. The inverter system comprises a first inverter system which is connected to one end of three phase windings of a stator and performs compensation of a back electromotive force; and a second inverter system which is connected to the other end of the three windings of the stator and performs reactive power compensation.

Abstract: A personal rapid transit (PRT) system having a linear induction motor installed on the bottom of a vehicle is provided. Since a linear induction motor is installed on the bottom of a vehicle, the structure of the personal rapid transit (PRT) system is simplified and the stable driving thereof is possible. Further, since an auxiliary ramification wheel is provided, an accident by the vehicle seceding from a track occurring during ramification can be prevented in advance. That is, since only a single linear induction motor is installed horizontally on the bottom of the vehicle and thus the vehicle is driven, the structure of the personal rapid transit (PRT) system is more simplified and becomes lighter, and a production cost can be reduced, in comparison with an existing system using a pair of linear induction motors. In addition, even if a ramification device is failed during ramification, a track secession can be suppressed with an auxiliary ramification wheel provided, to thereby guide a stable running.