This paper proposes a new torque priority control system based on a new voltage limitation method considering the q-axis current differential value for interior permanent magnet synchronous motors. The conventional torque priority control system with the M'-T' axis realizes a fine torque response. However, the operation time of the conventional system increases owing to coordinate transformation and calculation of motor parameters. As a result, it is difficult to implement the control system. The proposed torque priority control is able to reduce the operation time without degrading the torque response. The experimental results verify the effectiveness of the proposed torque priority control system.
In order to simulate the thermal conductivity of a power electronics system at a large scale, we have developed a new method involving the coupling of the finite element method and the admittance (Y) matrix method. This coupling method is applied to the simple test model, and its basic feasibility is confirmed because the simulation result was obtained within 6.5% of the numerical difference with the conventional FEM result.
Accurate estimation of self-position is indispensable for autonomous mobile robots. Map-matching-based self-positioning is one of the promising methods; however, adequate matching area selection is an issue to be solved. In this paper, we propose an adjustable map matching method that remedies a defect of the conventional template matching technology. The proposed method was evaluated experimentally, and the results verified the advantages of the proposed method.
This paper provides a new method to estimate very high frequency (VHF) conducted noise from power electronic devices using numerical analysis. The switching waveforms generated by power semiconductor devices, which are the main noise sources, are calculated by a circuit simulation that uses semiconductor device models. The transfer functions from noise sources to voltage measurement points are calculated by the S-parameters on a power electronic device. The S-parameters are calculated by a 3D electromagnetic simulator. The combined results of circuit simulation and electromagnetic analysis create a good correlation with the actual experimental result in the frequency range of 200MHz and below.
The coupling coefficient between the coils of a noncontact power supply system is reduced by coil misalignment. This reduces the output voltage and the active power in the coils. To cope with these problems, an instantaneous current control method is applied to a single-phase contactless power transformer system to apply the equivalent impedance of the PWM rectifier at the load side of the transformer. We propose a control method to supply power constantly to the load even when misalignment of the receiving coils occurs. The limit of the transferred power associated with the proposed control method is investigated. The proposed system, including the control method, is verified by experimental tests over a power range of several tens of watts.
It is important to use a robust servo system to improve the performance of motion control systems for several industry applications. Generally, a speed servo system has a controller with an integrator, such as a PI controller. When its output variable is saturated by current and voltage limits, a wind-up phenomenon and an unstable response often occur. We have already proposed an anti-windup algorithm considering voltage saturation for servo systems, and it regulates the current response smoothly and stably. However, the motor speed response exhibits a large overshoot caused by current saturation. This paper proposes an anti-windup algorithm considering motor dynamics and current saturation for speed servo system of surface permanent magnet synchronous motor. The experimental results show that the speed servo system employing the proposed algorithm regulates the motor speed smoothly and stably.
The authors propose a novel control scheme for an electromagnetic suspension system. The excitation current of an electromagnet is usually controlled using feedback gap sensor signals. An acceleration sensor signal is used in the proposed scheme, where the gap acceleration, integrated acceleration, and excitation current are considered as the state variables. The following three points should be noted: (1). the electromagnet is movable and supported by a spring-damper, because the acceleration sensor should not be attached to the controlled object; (2). the speed signal is stabilized by the integration of the acceleration; and (3). the observer is used to estimate the speed as a countermeasure of the integration drift problem. The authors show the state equation of the proposed scheme and the consequent controllability and observability; they then report the evaluation of the system using the experimental apparatus, as well as present the vibration characteristics of the controlled object.
Claw teeth motors have a feature that can make axial the length thin. This makes them suitable for appliances, automobile assistant machines, and small-sized industrial motors. On the other hand, there is a need to thin HEVs, elevators and large-sized industrial motors. In this study, we examined a higher output of the claw teeth motor. We arrived at the following conclusions as a result of our research. 1) The optimal stator structure was determined and the prospect of attaining the specification of 123N·m was determined. 2) A manufacturing subject called core assembly accuracy reservation, thin coil manufacture, and the rotator insertion method became clear. 3) The experimental results and the analysis results were in agreement with respect to the EMF. 4) The experimental cogging torque results and FEA results are in agreement in the 6th degree. But the 2nd and the 4th degrees of the experimental cogging torque results did not agree with the FEA results. 5) Although the core needed to be divided in the direction of the circumference for enlargement, it was clear that the influence on the torque is small. 6) Division of the core is a good solution for enlargement of the claw teeth motor.
This paper focuses on a battery energy storage system (BESS) that uses a multilevel cascade converter. This converter can individually manage each state of the battery connected to the DC side of each bridge cell by controlling the power of each bridge cell. However, this converter needs to cooperatively control the switching patterns of multiple bridge cells. PWM control method can solve this issue. One of the main PWM control methods employs a level-shifting carrier PWM technology. This method effectively controls bridge cells cooperatively, but it is difficult to change the power of each bridge cell intentionally for a short period, for example, a half cycle. We propose a control method based on level-shifting carrier PWM technology for a multilevel cascade converter. The proposed method can control the power of each bridge cell individually for a short period by exchanging switching patterns in multiple bridge cells. The validity of the proposed method is verified using an experimental single-phase battery energy storage system.
Traffic regulations mandate the use of winter tires in the interests of smooth traffic flow during heavy snow days. In this situation, road administrators must visually inspect vehicles to ensure summer tires are not being used on expressways. However misjudgment is unavoidable only by visual inspection and heavy traffic jams eventually occur. To avoid such traffic jams, an automatic tire discrimination system is required. In this report, we propose a simple method of discrimination between summer and winter tires using tire/road noises emitted by running vehicles, and evaluate the relationship between road surface roughness and the impact noise patterns of winter tires. Additionally, we consider the influence of road surface conditions such as dry and wet surfaces on the proposed discrimination method. Finally, we confirm the effectiveness of the discrimination system in the field using a number of vehicles with different tires.
In recent years, compact and lightweight boost converter systems have been required in hybrid electrical vehicle and electrical vehicle applications. For miniaturization of passive circuit components, such as the inductor and the smoothing capacitor, a multi-phase method boost chopper circuit with a coupled inductor has been proposed and discussed. In this paper, the stabilization digital control design technique for the multi-phase method boost chopper circuit with a coupled inductor is proposed.
Although switched capacitor converters (SCCs) offer high power density and a miniature footprint, applications of SCCs have been mainly limited to unregulated converters because the voltage conversion ratio of conventional SCCs is basically not controllable. This paper proposes a PWM-SCC that provides PWM-controllable high step-down voltage conversion. In comparison with a traditional buck PWM converter, the proposed PWM-SCC achieves higher step-down voltage conversion at a given duty cycle. An experimental test on a 30-W prototype for a 28-V input and a 6.0-V output achieved a power conversion efficiency of higher than 86% in the output power range of 10-30W with a duty cycle of 0.40-0.46.