This paper proposes an analysis of transition mode from phase-shift to zero phase-shift under ZVS and NON-ZVS operations for a series resonant inverter with the load of induction heating. A number of circuit operations during transition mode from phase-shift to zero phase-shift under ZVS and NON-ZVS conditions are first analyzed. Various voltage and current equations of the operating circuits are then obtained and used for calculation of the waveforms by the aid of MATLAB program. The calculated waveforms make possible the consideration of some important circuit parameters that are used to determine ZVS or NON-ZVS conditions. The theoretical results and proposed method are also verified by experimental ones, using a prototype test set in our laboratory.
Ultrasonic motors (USM) causes serious characteristic changes during operation. It is difficult for the conventional internal model control (IMC) proportional integral differential (PID) control to compensate such characteristic changes of the plant. To solve these problems, we propose a method of variable gain type IMC-PID control. In the proposed method, plant parameters are identified on line and these estimated parameters are used for adjusting three gains of PID. Then the proposed method makes it possible to compensate characteristic changes of the plant. The effectiveness of the proposed control method have been confirmed by experiments using the existing ultrasonic motors servo system.
This paper describes a novel commutation strategy for planar actuators with moving magnets and integrated magnetic bearing. The algorithm decouples the force and torque components directly and determines the current set-points of the coils by minimizing the ohmic losses. The algorithm can switch actively between different sets of coils and, consequently, the stroke of the actuator in the xy-plane is infinitely large. Furthermore, the technique is linked to the well known DQ0-transformation. The algorithm has been successfully tested on a magnetically levitated 6-DOF planar actuator with moving magnets.
In this paper is proposed a microstep control strategy, developed for linear switched reluctance step actuators characterized by magnetic dissymmetry between the end and the central phases. In this way, a parameterized finite element model is developed for the studied actuators, and used for electromagnetic force evaluation according to the plunger position and the supply currents of the phase. The obtained forces are regrouped within response surfaces which are inverted in order to determine the supply current configurations required for accurate microstepping.
A new voltage limiter for fast torque response of IPMSM in voltage saturation region is proposed, which we name “maximum torque response voltage limiter”. In transient condition, the fastest response is vital while voltage saturation occurs. Then the problem is that how to divide the limitted voltage to d and q axis voltages for generating the fastest torque response. The nonlinear relation between torque and d-q axis currents of IPMSM makes the problem complicated. In our proposed method, both voltage equations and a torque equation of IPMSM are considered and, based on Lagrange optimization technique, the explicit expression of d and q axis voltages are derived. Compared with the conventional voltage limiter such as constant phase angle method, constant back emf. method and constant d-axis voltage method, the proposed limiter yields faster torque response in voltage saturation region, which is confirmed by computer simulation and experimental results. Furthermore, the proposed method uses simple software calculation, and it can be readily implemented without any modification of hardware system.
This paper considers a human-operated task model based on identification techniques using switched systems expressed by mixed logical dynamical systems. In the system, each subsystem is expressed by a piecewise affine system. For a model to be identified, it is not easy to determine a number of subsystems in advance. In this paper, we propose a simultaneous identification technique which takes into account both a number of subsystems and parameters so that a piecewise affine model of a human operation can be obtained. In addition, the obtained model is applied to automation. The effectiveness of the proposed method is illustrated through simulations and experiments.
In this paper, we present an automatic train control method adaptable to disturbed train traffic conditions. The proposed method presumes transmission of detected time of a home track clearance to trains approaching to the station by employing equipment of Digital ATC (Automatic Train Control). Using the information, each train controls its acceleration by the method that consists of two approaches. First, by setting a designated restricted speed, the train controls its running time to arrive at the next station in accordance with predicted delay. Second, the train predicts the time at which it will reach the current braking pattern generated by Digital ATC, along with the time when the braking pattern transits ahead. By comparing them, the train correctly chooses the coasting drive mode in advance to avoid deceleration due to the current braking pattern. We evaluated the effectiveness of the proposed method regarding driving conditions, energy consumption and reduction of delays by simulation.
This paper describes characteristic analysis of a micro DC-DC converter which integrates inductor, controller and switching devices, and an improvement of transient response characteristic. The steady state operation and the efficiency characteristics of the micro DC-DC converter are shown as experimental data. And static characteristics are theoretically analyzed in consideration of DC current characteristics of the inductor. Moreover, the load transient response characteristics of the micro DC-DC converter are analyzed experimentally and theoretically. In addition, the factor that the overshoot and undershoot of the output voltage when the load changes are caused is discussed. Finally, the clamp circuit for reducing the overshoot and undershoot of the output voltage when the load changes is proposed.
A self-controlled synchronous motor is being used as a variable speed motor in industries to date, and nowadays it is also used for propelling a ship. In this type of motor, the information of rotor position is needed to achieve stable operations. A simple sensorless starting method for this motor is studied in this paper. An initial rotor position detecting method without any position sensor is first discussed. It is shown that the position can be detected easily by observing the electromotive forces induced in the armature windings due to the change in the field current. Then, a new starting method for the motor is proposed on the basis of the DC link current chopping during the starting period. It is clarified that based on the proposed method the starting of the motor can be realized independently of the load conditions, supporting the usefulness of the proposed method. Finally, the effects of various parameters in the system on the responses of dc input current and motor speed during starting up are discussed.
This paper focuses on voltage-balancing control suitable for a three-level diode-clamped PWM converter used in a hybrid active filter. A three-phase downscaled system including a 400-V, 15-kW three-phase diode rectifier with a capacitive load as a harmonic-producing load is designed, constructed, and tested to verify the filtering performance of the hybrid filter and the voltage-balancing control performance of the three-level PWM converter. Experimental results, along with theoretical analysis, verify that the voltage-balancing control proposed in this paper works properly in all the operating regions from full-load to no-load conditions.
In this paper, current control method for High-Speed AC Motor System is proposed. In High-Speed driving operation, Current controller tends to lose stability because of dead time caused by computational delay and Electromagnetic coupling included AC Motor Model. The Main purpose of the proposed method is reduction of dead time on current controller. Proposed method based model predictive control and optimizing of start timing. The Effectiveness of proposed method is confirmed by simulation results.
This paper presents a novel feedforward compensation for the fast and precise positioning control in mechatronic systems. The proposed compensator is designed considering the frequency shaping in control input to suppress the residual vibration, under the constraint of specified step number in position reference. A 2-degrees-of-freedom positioning controller with the proposed feedforward compensation can ensure the required settling performance with the specified steps regardless of the positioning amplitude in reference. The effectiveness of the proposed approach has been verified by numerical simulations and experiments using a prototype of galvano scanner.
Electric power steering (EPS) motors need to have characteristics like precision machines. They should be small and produce high power. Moreover, both their loss torque and the change in their loss torque should be ultra low. In this study, dividing the stator core into small blocks and winding the coils densely on the blocks were shown to be effective techniques for achieving small high-power motors. For this paper, we examined whether “I-shaped divided cores” or “T-shaped divided cores” were more suitable for EPS motors in terms of motor performance and productivity. We built two experimental motors, one with “I-shaped divided cores” and the other with “T-shaped divided cores”, and measured three important characteristics for EPS motors: output torque, loss torque, and loss torque change. As a result, the “T-type” motor proved to have better performance for all three characteristics. Moreover, the motor productivity of the “T-type” motor was shown to be higher than that of the “I-type” motor. So, we clarified that overall, T-shaped divided cores are advantageous for the stators in EPS motors. Next, we considered a new winding method for the continuous winding of two “T-shaped cores” in order to achieve a compact terminal connection part. The extending line that was made by the new winding method stays at the coil end. Therefore, this method will contribute to the axial miniaturization of EPS motors.
Nitrogen oxide (NOx) and carbon dioxide (CO2) emissions from vehicles have been increasing every year because of the growing number of vehicles, and they cause serious environmental problems such as air pollution and global warming. To alleviate these problems, this paper proposes a new traffic signal control method for reducing vehicle NOx and CO2 emissions on arterial roads. To this end, we first model the amount of vehicle emissions as a function of the traffic delay and the number of stops at intersections. This step is necessary because it is difficult to obtain the amount of emissions directly using traffic control systems. Second, we introduce a signal control model in which the control parameters are continuously updated on the basis of predictions of arrival traffic flows at intersections. The signal timings are calculated in such a manner so as to minimize the weighted sum of the two emissions, which depend on the traffic flow. To evaluate the validity of this method, simulation experiments are carried out on an arterial road. The experiments show that the proposed method significantly outperforms existing methods in reducing both the emissions and travel time.