Drive of permanent magnet synchronous motor (PMSM) requires the rotor position information to control the motor torque, and they are generally detected by mechanical position sensor such as an encoder or a resolver. However, these sensors increase the machine size and the cost of drive, and reduce reliability of the system. Therefore, many papers about position sensorless drive method of PMSM have been published. This paper presents a position sensorless control of interior permanent magnet synchronous motor (IPMSM). A mathematical model of IPMSM using an extended electromotive force (EMF) in the rotating reference frame is utilized to estimate the rotor speed and position. This model has a simple structure integrating position information into an extended EMF term. Therefore, the sensorless control based on the mathematical motor model can be simply implemented. The estimation method proposed is based on the principle that the error of the current is proportional to that of extended EMF. This method was carried out using a 6-pole, 400W, 1750r/min test motor system. As a result, the sensorless speed control was achieved from 80r/min to 1800r/min under 0-100% loads.
In this paper, construction logic of a man/machine safety work system is presented. Especially in a system where the human and machine cooperatively work on the time axis, safety assurance requires the human and machine to maintain different positions or states. A control of this positional relationship or state change is defined as block section control. In Chapter 3, the safety of the platform door system composed of train doors and platform doors is discussed. These systems are characteristic in that it has two or more safe areas and that its hazardous area change to safety area. The concept of the man/machine safety work system is applied to the station platform door system, and the conditions for assuring the safety of the control the station platform door system are derived.
This paper presents core loss evaluation of turbine generator model stator. The stator configuration does not make magnetic flux distribution uniform, and the induction harmonics make the core loss calculation difficult. In this evaluation, the core losses are measured by rotating stator torque. As a result of the measurements, a half-lap-stacked stator obtains lower core losses and larger percentage of eddy current losses than a block-stacked stator. In addition, a gap between each segment makes in-plane eddy current loss increase.
This paper describes an ultra high-speed permanent-magnet synchronous motor drive, which is embedded in a turbocharger of an internal-combustion engine. The electrical drive makes it possible to enhance output power of the turbocharger in a motoring mode and to retrieve combustion energy from exhaust gas in a regenerating mode. Computer simulations and experimental tests are conducted to examine various operation characteristics of a prototype. The experimental data demonstrate 220000-r/min operation at 2.2-kW inverter output power, which agree with the simulation results well and prove feasibility of the proposed system.
The multi-car elevator system in which two or more cages run at one shaft will be one of the elevator systems in the near future, in order to solve increase of the traffic demand in high-rise buildings. In this paper, we propose the calculation method of handling capacity for multi-car elevator systems two cages run at one shaft, or two or more cages run in the same direction at a loop-type shaft, in consideration of the position of cages in the same shaft. And we propose the design method for multi-car elevator systems, which decides the required number of cages, branches and shafts to meet the traffic demand. Moreover, we compare handling capacity of multi-car elevators and investigate optimal elevator facilities for high-rise buildings.
The author's previous study proposed an efficient design method of time-varying gain type controller and its application to the positioning control of vibration systems. The responses of this method become similar to the responses of conventional nonstationary optimal regulators (NORs). This method calculates a time-varying Riccati equation and the responses of a controlled object simultaneously. Moreover, this study utilizes the random search technique for the tuning of the time-varying weights in the Riccati equation and realizes the efficient controller design under many control constraints. Following the previous study, this paper improves the previous method by taking the influences of parameter variations into account. This paper demonstrates an algorithm for the case which includes mass and friction variations. The effectiveness of the algorithm is verified by numerical calculations. Moreover, this paper also discusses some experimental investigation. Different from the use of NOR, the time-varying gains in this experiment are obtained by real-time computations.
This paper presents a control strategy of the step-down chopper in a single-phase utility interactive photovoltaic generation system with a PWM current source inverter. The chopper regulates the dc current under fixed PWM operation of the inverter and the switching of the chopper contributes achieving the smooth dc current. The experimental results prove that the dc current pulsation is suppressed enough and the proposed method is applicable to power control of the PV arrays.
A novel snubber energy recovery bridge leg for rectifier applications is presented. When the controllable power devices assembled into this bridge leg are turned on, the snubber capacitor is discharged and its stored energy is transferred to the load circuit. The currents flowing through power devices are also limited to the dc current. As a single-phase rectifier example, the experimental prototype employing two insulated-gate bipolar transistors is implemented to investigate the operation under the pulse-width modulation. The experimental results confirm that the input current can be waveshaped sinusoidally with a near-unity power factor.
The harmonic wave of the exciting current of the motor is generated by the pulsewidth modulated voltage of the inverter. The motors that have low inpedance genetate more harmonics and make larger iron loss. This paper describes an implementation of drive control for a small inductance permanent-magnet motor drive. A comparative experiment has been carried out with conventional methods and the utility of the proposed method has been verified.
Since d-c compound motor have wide industrial applications, theoretical and experimental research in such systems are assumed to be special importance. In previous work, we studied a new d-c compound motor which is suitable for the electronic vehicle and bicycle. This paper provides the fixed velocity characteristics for an electrical vehicle with the new high-efficiency motor. Experimental results show that the electric vehicle with new compund motor is more effective than the conventional one.