A novel circuit topology of output levering circuit for a wind generation system is proposed. This circuit is consisted of two chopper circuits, batteries and EDLC. Two storage components are connected in series. In this paper, characteristics of the poposed circuit can be clarified by experimental results.
This paper presents an analysis of the current control for converters without electrolytic capacitors for light-emitting diode(LED) lamps. Although LEDs are long life, the life of drivers using the electrolytic capacitors is less than the one of LEDs. Therefore filmcapacitors are applied instead of electrolytic capacitors. However, a fluctuation of LED current increases since the capacitance is reduced.In order to avoid the flickers, the current controller must reduce the fluctuations. To analyze and simulate inductor currents of the converters, nonlinear systems are employed. Prototype converters are implemented by a micro controller. It is shown that the proposed analysis is good agreed with simulation results and experimental results.
Silicon carbide Schottky barrier diode (SiC-SBD) is expected to be a candidate instead of silicon fast recovery diode (Si-FRD) over 600V. We compare some electrical characteristics of conventional Si-FRDs with those of our SiC-SBD samples. We also prepare three types of SiC modules. One is hybrid IGBT module consisting of Si-IGBT and SiC-SBD, another is SiC-SBD module and the other is hybrid intelligent power module (IPM) with Si-IGBT and SiC-SBD. In addition, we confirm the power loss reduction effect of 10kWsolar power conditioner and 8kW 3-phase PFC converter by using each module.
The high frequency inverter with the power control capability which realizes the high power density is attractive and remarkable. However, switching loss increase by the high speed switching operation is significant problem. This paper dealswith a novel zero current switching (ZCS) circuit topology suitable for phase-shift controlled ZCS inverter. This circuit has soft-switching capability in the MHz switching range by the ZCS circuit topology and can control the output power by the phase-shift controlled method. The circuit operation principle and its switching performance are described and discussed from a simulation and experimental results.
we propose an 18-step hybrid diode rectifier by harmonic injection. Circuit performances of the proposed dioderectifier are discussed by graphical analysis. Then, effects on harmonic reductions can be clarified by theoretical and experimental results.
The work presented here is a first prototype of AC/DC converter for T8 LED lamp application. Main merits of this circuit are: High power factor, High efficiency and Intrinsic dimming function. Proposed design is based on the operation concept of Magnetic Energy Recovery Switch (MERS). Turn-on and turn-off intervals are under soft-switching regimes, allowing minimum stress and power losses on switches. The circuit still is on development process and there are several problems to tackle. Main challenges are: Cost, competitive size and minimum voltage DC ripple without electrolytic capacitors.
For rectifier circuits with power factor correction, boost converters are generally used. As some restraints, it can be mentioned that the output voltage becomes limited to relatively higher voltage range. To expand the controlled range, buck-boostincluding like the Cuk converter types could be sometimes effective, because it has abilities to step-up and step-down over a widerange. This paper presents and discusses on a circuit configuration with power factor correction using buck boost converters. For the working process, various choppers having buck-boost function are compared and discussed with respect to some circuit characteristics and functions. Firstly, the paper discusses about the mechanisms of the power transmission and the characteristics based on the switching ripple and switching surge voltage of various converters. The distinction among buck boost converters are mentioned and discussed analytically. From such result, it can be seen that the canonical switching cell is mostly suitable for the single-phase power factor correction as buck boost chopper.
As increasing installation of renewable energies which are accompanied by self-commutated power converters, installed capacity of the converters cannot be negligible as compared to the total generation capacity. Those self-commutated converters trade active power with adjusting their output voltage phase angle according to the voltage at the point of commoncoupling (pcc). Therefore, increasing installation of the self-commutated power converters may result in reducing a synchronizing torque of the power system. The tendency is remarkable in a microgrid where the rate of converter-based generation is high. The synchronizing torque is supplied by traditional synchronous generators inherently because, at some disturbance, their inertias make phase differences among their terminal voltages and they can trade active power by the phase differences. In order to keep the synchronizing torque under high penetration of renewables, a concept of Virtual Synchronous Machine was proposed. The VSM emulates a conventional synchronous generator and realizes the power trade among them. This paper deals with a controller of self-commutated converter like the VSM. Instead of applying the same characteristics of the conventional synchronous generator, the phase angle of the output voltage is adjusted as lead or lagged to the pcc voltage in order to trade the active power. The effectiveness of the control is verified in a microgrid system model where the rotating generator and self-commutated converter have almost same rated capacity. The effectiveness of the controller is verified from the viewpoint of frequency control through some simulation studies.
The wind energy is a clean and renewable energy source. Recently many wind turbine generation systems have been installed in many countries from the viewpoint of global warming. In the near future, the full rating inverter/converter-based wind energy conversion system using permanent magnet synchronous generator (PMSG) is expected to become popular. The wind generator using PMSG can operate in the maximum power point tracking (MPPT) mode. In addition, it also has a high capability for problems such as Fault Ride Through, active power and reactive power control issues, and voltage regulations. We already proposed a model following controlled PWM inverter in which the proposed controller has robustness. The proposed inverter can output sine wave voltage regardless of rippling input voltage. This paper describes the fundamental performance of the discrete-time model following controlled PWM inverter for wind turbine generator system through numerical simulation analyses.
The PM motor has become increasingly popular for many applications. We proposed a novel synchronizing signal sensor-less vector control method without using any machine model parameters to be able to drive any AC motors. The proposed system was able to be easily constructed without any motor parameters. So far, we proposed electric vehicles (EV) driven by induction motor and PM motor using the proposed sensor-less control method. Moreover we developed a prototype Hybrid Vehicle (HV) driven by an AC Synchronous Motor (SM) with a developed an inverter unit. The HV was converted from a general gasoline vehicle, which is MITSUBISHI LANCER EvolutionⅣ -CN9A. The HV was reconstructed by an IMsynRM (15kW) and SPMSM(10kW), lead acid batteries (300V, 16Ah), and the handmade inverter units using IGBT devices (Generator unit 600V-400A, motor unit 600V-600A). Total weight of the HV is approximately 1,600kg. In this paper, we introduce the development process and features of the HV. Furthermore we report characteristics of IMsynRM that we developed.
This paper represents the practical evaluations of an improved time-sharing high-frequency resonant soft-switching inverter for all metal induction heating (IH) cooking appliances. By introducing inductor coupling technology, the number of the circuit components and a physical volume of the circuit can be reduced. A design procedure of the coupling inductor is discussed in detail. Furthermore, two IH power regulation sequences; phase shifted PWM and PAM are compared to the viewpoint of the power conversion efficiency.
The research of the electric propulsion system that includes the rotating field antenna is making a remarkable progress with the both plasma heating and generating. The propulsion system in the satellite and/or a shuttle with a high-frequency inverter based drive system becomes effectively realized. Because this new type of magneto-plasma thruster system is an effective method to realize the both plasma production and ion heating in independence. This paper deals with the novel circuit topology and its control characteristic of a dual output high frequency inverters that considered the characteristic of the rotating field antenna. In addition to this, a novel inverter topology suitable for a phase-shift controlled electric propulsion system which includes the both Quasi zero current switching (ZCS) and Quasi Zero Voltage Switching (ZVS) circuit is presented in this paper. The circuit operation principle and its switching performance are described and discussed on the basis of a simulation.