A new motor has been developed for use in a new fuel cell vehicle. By applying a new rotor magnetic circuit, stator core production method and current control a quiet, powerful and smooth driving experience is achieved. Compared to the previous motor, the maximum power was increased from 100kW to 130kW and the maximum torque was increased from 256Nm to 300Nm. In addition, the motor noise inside the cabin was reduced by 5 to 10dB(A) compared to that of the previous motor.
This paper deals with the thermal resistance and thermal conduction characteristics of a Nickel Micro Plating Bonding (NMPB) power module in comparison with those of a power module adapting a conventional structure with a high-temperature solder attachment. An attempt is made to estimate the thermal resistance and thermal structure function for the two types of power modules when peeling of the chip junction occurs. In terms of spreading heat, an NMPB is superior to a conventional power module using high temperature solder, because NMPB allows spreading heat from both sides of the chip and setting the heat spreader near the chip.
External position sensors such as linear scales are frequently used in motion control systems of industrial machines, and they form a full-closed position feedback loop for accurate positioning. When the velocity signal calculated with the position signal from the motor encoder is used for the velocity control loop, resonance is less likely to occur than when using the velocity signal calculated with the position signal from the external encoder. If the position loop gain is increased, vibration is generated at the anti-resonant frequency, even if the velocity loop is stably controlled with respect to the resonance frequency. Since there is no control method for suppressing the vibration, such as the vibration control method in semi-closed control, the proportional gain of the position feedback loop cannot be made sufficiently high. In this paper, we propose a full-closed control method that suppresses the vibration at anti-resonance frequency and confirm its effectiveness through simulation and experiment.
The purpose of this study is to develop power circuits for AC electric trains with weight reduction and downsizing. We devised a new power circuit configuration which uses SiC modules for insulation function instead of the main transformers, manufactured the circuit models on an experimental basis, and executed the verification. The results verified the bidirectional operation, demonstrating that about a 5.7kW of power was transmitted for the input voltage of up to 200V and the switching frequency of 20kHz run, while ensuring the insulation state without any simultaneous conduction between the primary and secondary terminals through the flying capacitor.
This paper proposes a capacitor pre-charge method using a bi-directional isolated DC-DC converter. This converter topology works as a phase-shifted full bridge DC-DC converter under forward direction of power conversion. In addition, this converter topology works as a current-fed converter under backward direction of power conversion and can operate in both the buck-mode and boost-mode. Then, a switching control method is presented for the voltage critical area of buck-boost. Appropriate input current control can be achieved by this switching control method in the voltage critical mode of buck-boost. Finally, the effectiveness of this pre-charge method is verified through an experiment on pre-charge using a 200V, 1000µF capacitor.
We built a prototype motor with NANOMET stator cores. NANOMET is one of the several nanocrystalline soft magnetic alloys. The motor iron loss and other characteristics of NANOMET were compared with 35A360, which is one of the widely used conventional electromagnetic steel sheets, and the effectiveness of the new material is shown. This paper describes the methods to build NANOMET stator cores, and presents the evaluation results of the prototype motor.
This paper presents the power flow control in wireless power supply systems using a matrix converter that directly converts from three-phase AC voltage to high-frequency AC voltage. The operation principle and control method that achieve stable power transmission on the secondary side and reduction of current distortion in three-phase AC current are explained. In addition, the switching patterns and duty ratios of the six bidirectional switches of the primary side matrix converter are clarified, and the effectiveness of the proposed control method is experimentally verified using 2kW prototype system.
This paper proposes a method for torque ripple estimation and reduction of interior permanent magnet synchronous motors (IPMSMs) with concentrated winding considering the nonlinearity of magnetization characteristics. First, the proposed torque ripple estimation method, which ignores nonlinearities such as magnetic saturation and cross-coupling, is derived and some problems of this approach are presented. Then, another method that considers the nonlinearity of the magnetization characteristics is proposed, which is based on simple approximations of the magnetization curve. After that, a method for torque ripple reduction is proposed, which is based on the adaptive identification of the equivalent torque coefficient. Finally, the performance of the proposed method is experimentally evaluated to demonstrate the feasibility of the proposed method.