Recently, high-precision tracking control has been required for optical disks. For this purpose, we have previously proposed a tracking control system that is composed of an equivalent-perfect tracking control (E-PTC). However, the conventional control system is not able to operate the inverse system properly for the state equation. In this paper, we propose a new double E-PTC system. With this new system, the inverse system for the state equation operates properly. In addition, we propose a double E-PTC system with an error-based disturbance observer using a notch filter for non-periodic disturbance suppression. The proposed system achieves more precise control and experimental results demonstrate its effectiveness.
This paper describes a novel electric double-layer capacitor (EDLC) regenerative braking control scheme for electric-powered wheelchairs that provides efficient driving planning. Electric-powered wheelchairs generate their driving force using electric motors and are expected to be widely used as mobility support systems for elderly and disabled people. However, their energy efficiency has to be further improved because they are driven only by battery energy. This study proposes a deceleration control scheme with EDLC charge/discharge and jerk and deceleration limitation. The decelerating velocity reference is designed to increase the regeneration energy and reduce the consumption energy based on real-time continuous deceleration pattern generation with jerk limitation. Some experiments are performed to verify the effectiveness of the proposed system.
Lightweight and compact high-power-density boost converters are required for many applications. This paper presents a three-phase interleaved boost converter with a novel coupled inductor that can achieve high-power-density. The novel coupled inductor is especially suitable for the three-phase interleaved boost converter, from the core structure standpoint. The electrical and magnetic characteristics of the three-phase interleaved boost converter are analyzed in detail to illustrate the effectiveness of the novel coupled inductor. Furthermore, maximum output power calculation methods for the novel coupled inductor and a non-coupled inductor are proposed to demonstrate the performance of high-power-density converters. On the basis of the calculation method, the maximum output power of the proposed coupled inductor is about 2.6 times greater than that of the non-coupled inductor under continuous current mode (CCM) conditions. The compact volume, low-weight characteristics, and the performance of the three-phase interleaved boost converter with the novel coupled inductor are discussed from both the theoretical and experimental standpoints.
This paper describes the evaluation of the IGBT partial turn-off behavior through three types of circuit topologies: hard switching (SW), Zero Voltage Switching (ZVS), and Tail Loss Cancel (TLC) method. Under-zero current switching (UCS) was examined through the high power back to back (BTB) experiment using a 90kW 3-phase interleaved chopper. The proposed Snubber Assisted Zero voltage and Zero current transition (SAZZ) topology obtained the highest efficiency of 97.42% at 30kW, 1.82% higher than hard SW (95.6%), and the highest efficiency over the entire power region. This was verified through the load test and loss breakdown up to 30kW per phase, and its performance for the under-zero current switching behavior was confirmed.
This paper proposes a parallel operation system of permanent magnet synchronous motors (PMSMs) and verifies the suppression effect of the proposed damping control for the torque vibration caused by resonance between synchronous reactance and inertia moment. The proposed system is composed by two types of power converters, a main inverter with a V/f control and an auxiliary inverter with the field-oriented control and the damping control. In general, PMSM cannot be driven by the V/f control such as an induction motor because the speed vibration is caused by the resonance between the synchronous reactance and the inertia moment. In the proposed system, the multiple PMSMs are driven in parallel by the main inverter with the V/f control. When the motor speed vibration occurs, the damping control for the auxiliary inverter suppresses this vibration in PMSM. From the frequency characteristics, it is clear that the power capacity of the auxiliary inverter is 10% lower than that of the main inverter when the frequency components included in the speed command are lower than 12rad/s. As a result, the experimental results demonstrated that the proposed system can reduce the speed vibration from 400r/min to nearly 0r/min with the damping control in our prototype of 1500-W PMSM drive system. The experimental results well agree with the theoretical analysis results.
A contactless DC connector concept has been proposed for next-generation 380-V DC distribution systems in data centers. An LLC resonant DC-DC converter topology with gallium nitride (GaN) power transistors has been applied to realize a highly efficient inductively coupled contactless connector. A prototype of a 1.2-kW 384V-192V contactless connector has been fabricated. An efficiency of over 95% and an ideal power density of over 5.0W/cm3 have been confirmed experimentally under 500-kHz operation. Design considerations for the proposed connector have been also conducted, and the approach for achieving a higher power density of 10W/cm3 has been presented. The proposed concept contributes to realizing a high-power-density DC distribution system because the functions for both the isolated DC-DC converter and conventional connector are integrated in a single instrument.
In this paper, we propose an automated method for measuring the aggressiveness of driving behavior by using driving signals from drive recorders. Currently, some risk consulting companies have experts review recorded driving behavior and then rate the drivers empirically. This approach is time-consuming and expensive, however, so an effective automated driver evaluation method is desired. We assumed that the aggressiveness of a driver's behavior can be determined by focusing on four types of vehicle operation behavior: steering, acceleration, deceleration, and alternation between acceleration and deceleration. Aggressiveness scores can be assigned to each of these behaviors, and a driver's overall aggressiveness score is then estimated by integrating these behaviors using multiple linear regression. We assessed the aggressiveness of 78 drivers and compared our assessments to the aggressiveness scores assigned empirically by the risk consulting experts. The proposed method achieved a rank correlation coefficient of 0.74 with the evaluations of the risk consulting experts.
When a workpiece is heated by eddy currents using a zone-control induction heating (ZCIH) system, there exists both inductance and resistance in the induction heating circuit. To efficiently control a ZCIH system, the detailed behavior of the self inductance and equivalent resistance of each coil and the mutual inductance and equivalent resistance between the coils should be clarified beforehand. This paper proposes the concept of the self- and mutual-equivalent resistances in the eddy current circuit and discusses the theoretical physical meaning and properties of these parameters. We also derive a theoretical formula for these parameters using a simple assumption and then examine their properties.