In this paper, the EMI noise characteristics on a three-phase SJ-MOSFET inverter composed of a pulse transformer type recovery-assist circuit are experimentally verified. First, the configuration and operation principle of the proposed pulse transformer recovery-assist circuit are described and an example of implementation to a 3.7 kW three-phase SJ-MOSFET inverter is presented. Next, the conducted noise and the radiated noise in case of driving a three-phase 3.7 kW induction motor with or without a recovery-assist circuit are verified. The EMI noise characteristics are measured based on CISPR11 at EMC site. Finally, the difference between EMI noise with and without a recovery-assist circuit is verified from the viewpoint of"Modeling of EMI noise source p"roposed by the author.
This paper describes how radiation noise of SiC-MOSFET and GaN-FET inverter differs from conventional IGBT and SJ-MOSFET inverter from benchmark test results using a 3.7 kW three-phase inverter circuit. Specifically, IGBT (2 types), SJMOSFET (2 types), SiC-MOSFET, GaN-FET (1 type each) are mounted on the DC 300 V input 20 A output three-phase inverter configured with TO-247. Only the gate drive circuit is designed as a power device recommended condition, and the other circuit configurations including the snubber circuit and the constants are unified. Next, observe the switching waveform with each inverter and measure the radiation noise when driving a 3.7 kW three-phase induction machine at a switching frequency of 10 kHz with a 10 m method based on CISPR at the EMC site. Finally, the difference of the radiation noise by the power device is verified from the viewpoint of "Modeling of EMI noise source "proposed by the author.
A new prototype of a soft-switching three-phase utility frequency ac to single-phase high-frequency ac direct power converter for induction heating (IH) applications is presented in this paper. The newly-proposed ac-ac converter features direct frequency conversion under the principle of series resonance and soft switching operations with minimized number of bidirectional switches. The validity of the proposed ac-ac converter is revealed by essential experimental results with a 3.5 kW-40 kHz prototype.
This paper deals with a dual active bridge (DAB) converter based battery charger in a stand-alone wind power generation system with a high-inertia small-scale wind turbine. The conventional proposed system needs four converters from a generator to the motor load. This proposed system can improve power conversion efficiency by reducing the number of converters. The DAB converter performs as battery controller. When the generated power is larger than the consumed power of the motor load, the DAB converter acts battery charging mode. On the other hand, when the generated power is smaller than consumed power of the motor load, the DAB converter acts battery discharging mode. Simulation results demonstrate that the proposed system can control the power flow in the stand-alone wind power generation system.
We proposed a mind hybrid system using an alternator for medium-sized vehicles,and confirmed the fuel consumption reducation effect by experiments. However,medium-sized vehicles with large inertia consume much energy as heat during deceleration.Therefore,it is important to regenerate the kinetic energy of the vehicle with high efficiency. The amount of regenerative energy leads to low fuel consumption.
In this paper,the standard alternator is modified to the winding switching type alternator.By moution this alternator on a vehicle,regenation of decelerating energy has increased.We report that the improvement has been confirmed by the modification.
In the power electronics field, the movement of the conduction EMI standard to be expanded to 150 kHz or less is being carried out at IEC. In the frequency range below 150 kHz, it is necessary to take measures against noise from the fundamental wave. In this report, we describe the situations that the effect of filtering measures on frequency range and measurement conditions of 150 kHz or less and 150 kHz or more are studied.
This paper presents a stability analysis of a closed loop controlled dual active bridge (DAB) dc-dc converter. At first, a discrete time model of a DAB dc-dc converter considering dead time effects is developed. Then, the stability of the output voltage control for DAB dc-dc converter is analyzed. Finally, the theoretical results are verified with a circuit simulator.
In order to reduce copper loss, high step-down DC-DC converter often employs center-tapped rectifier. In addition, a plate shape one turn coil is utilized for transformer for making a high step-down ratio. We focused on the proximity effect in plate shape one turn coil, and investigate the cause of worsening the copper loss. In this paper, based on this investigation, we propose rectification method using winding integrated with rectifier. In addition, we discuss practical issues of the proposed method and present the solution strategy. The proposed method is verified by experiments, which suggests the effectiveness of the proposed method to high current applications.
This paper describes a study on 500Hz modular multi-level converter(MMC) using real time simulators. Integral time step in real time simulation is limited to keep real time performance. The outline specification of experimental model, control system for MMC, and results of off-line simulation and real-time simulation using two real-time simulaters are reported.
In decade years, the magnetic coupled resonance have been attracted interest to realize the effective WPT (Wireless power transmission) system under the long distance condition. The novel power transmission coil structure, which is consists of the additional resonant tank circuit nearby and connect with the transmission coil, is proposed in this paper. The effectiveness of additional resonant circuit topology to improve the power transmission efficiency are explained and discussed based on the simulating results.
A battery (BT) power conditioning systems (PCSs) is expected to be an effective system for coping with the energy issues we will face in the future. This paper establishes an energy system with BTs that will corresponding ‘upward and downward Demand Response (DR)’ by using receiving power variable control of PCS. According to the measured receiving power, energy management system (EMS) control is enabled by using receiving power variable control of PCS without using the exclusive controller. The effectiveness of this system will be verified using simulation and actual equipment.
As the penetration level of variable-speed wind turbines continues to increase, characteristics of low inertia and lack of synchronous power of such devices can have a serious impact on the transient stability of a grid. One solution toward stabilizing such a grid with renewable energy sources is to provide additional inertia and synchronizing power in a virtual manner. This paper proposes an optimal control method that can follow the virtual generator model under constraints. As a result, it was shown that proposed method was possible to suppress the peak of the filter input power in instantaneous voltage drop.
High-speed motor driven in low voltage are used in equipment such as electric reel and handy vacuum cleaner. If a motor with a general structure used in an operating range of several thousand revolutions is used as it is in a high-speed range of several tens of thousands of revolutions, efficiency will decrease due to a large amount of iron loss. In this paper, we proposed models in which the stator teeth length and the magnet material were changed in order to suppress the iron loss that causes the efficiency reduction of the high-speed PM motor. In this case, since the eddy current loss occurs in the armature conductor, the effect of reducing the conductor eddy current loss by using the Litz wire was also examined. As a result, it was shown that the proposed model improves the efficiency compared to the conventional structure.
In this paper, we propose the system of SP-type resonant circuit with the DAB DC-DC converter for the wireless power transfer. We derive a non-tight transformer circuit and its equation, which using a coupling coefficient and turn ratio, to design for our system. By this derived circuit equation, it is also possible to derive the resonant capacitor parameters for the SP-type resonant circuit and a block diagram. This block diagram is possible simulating while varying the coupling coefficient. Also, we design that this system controls DAB DC-DC converters while synchronizing with each microcomputer. We confirm that the converter control operates normally, and it was clarified that the SP-type performs power transmission efficiency of 90% or more between two power transfer coils and that bidirectional power transmission.