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In this paper, a case study application of a new device, which is based on a bipolar-MOSFET cascode connection, is presented. The monolithic device can be designed for high-voltage applications up to 1.7-2.2 kV. The basic features of this power device are described in terms of the physical structure and the electrical performance. An application in the field of dc-dc converters is presented, and the drive unit requirements are investigated and discussed through several circuit topologies that are devoted to energizing the four-terminal device. The advantages and the drawbacks of the device are compared with those of a MOSFET in terms of the switching losses and the command circuitry. The correlation between the physical structure of the cascode and its electrical characteristics is explained to better understand some interesting features of the device. Last, the new device is tested by using a forward converter as a workbench to provide converter designers with useful guidelines concerning the switching behavior and the power losses. Index Terms--Bipolar junction transistor (BJT), cascode, forward converter, metal-oxide-semiconductor field-effect transistor (MOSFET).

This paper presents a new approach in realizing various carrier-based pulsewidth-modulation techniques by a generalized control algorithm, which is referred to as the universal control algorithm and is obtained via unequal sharing of null states. The flexibility of such an approach allows one to easily and quickly control two-level inverters. Furthermore, this approach may be also extended with few changes to the control of multilevel inverters. The algorithm that is presented here for two-level voltage-source inverters (VSIs) also obtains efficient detection and management of both the linear and overmodulation ranges. In the overmodulation range, which is treated by using the [alpha]-[beta] components of the reference-voltage space vector, the algorithm shows the advantage of lower calculation time, thus allowing one, if required, to increase the switching frequency. Several simulation runs have been performed, aiming to test the proposed procedure for both two-level and multilevel VSIs. Finally, the new algorithm was experimentally validated in the case of two-level inverters by using it in a VSI workbench that can carry out several experimental tests. Index Terms--Multilevel inverter, overmodulation, pulsewidth modulation (PWM), space-vector modulation (SVM), voltage-source inverter (VSI).

In this paper, standard-cell Schottky rectifiers along with silicon-based merged p-i-n-Schottky (MPS) and p-i-n diodes, which are realized using a super junction technology, have been analyzed and compared by conducting extensive device and mixed-mode simulations through a 2-D finite-element grid. The main issues that concern these devices, such as the forward voltage drop, the leakage characteristic, and the reverse recovery, are treated, and the superior performances exhibited by the MPS rectifier with respect to the p-i-n diodes are experimentally validated. First, the basics on the used technology are reported by focusing on the high voltage capability of the new devices along with the low forward voltage drop during the ON-state conduction. The reverse-recovery behavior belonging to the MPS diode has been analyzed by exploring through several simulations the internal plasma dynamics. 2-D simulations of the turn-on behavior relative to the Schottky, p-i-n, and MPS rectifiers have been carried out in order to analyze the effects of the voltage overshoot phenomenon eventually occurring in the three diode structures. Index Terms--Merged p-i-n--Schottky (MPS) diode, physics-based model, p-i-n diode, Schottky diode, super junction device.

In this paper, a new loss minimization control algorithm for inverter-fed permanent-magnet synchronous motors (PMSMs), which allows for the reduction of the power losses of the electric drive without penalty on its dynamic performance, is analyzed, experimentally realized, and validated. In particular, after a brief recounting of two loss minimization control strategies, namely, the 'search control' and the 'loss-model control,' both a new modified dynamic model of the PMSM (which takes into account the iron losses) and an innovative 'loss-model' control strategy are presented. Experimental tests on a specific PMSM drive employing the proposed loss minimization algorithm have been performed, aiming to validate the actual implementation. The main results of these tests confirm that the dynamic performance of the drive is maintained, and in small motors enhancement up to 3.5% of the efficiency can be reached in comparison with the PMSM drive equipped with a more traditional control strategy. Index Terms--Control systems, efficiency improvement, permanent-magnet synchronous motor (PMSM), variable-speed motor drives.

In order to evaluate the fuel and energy savings, and to focus on the problems related to the exploitation of combined renewable and conventional energies, a logistical model for hybrid generation systems (HGS's) has been prepared. A software package written in ACSL, allowing easy handling of the models and data of the HGS components, is presented. A special feature of the proposed model is that an auxiliary fictitious source is introduced in order to obtain the power electric balance at the busbars during the simulation stage and, also, in the case of ill-sized components. The observed imbalance powers are then used to update the system design. As a case study, the simulation program is applied to evaluate the energetic performance of a power plant relative to a small isolated community, an island in the Mediterranean Sea, in order to establish the potential improvement achievable via an optimal integration of renewable energy sources in conventional plants. Evaluations and comparisons among different-sized wind, photovoltaic, and diesel groups, as well as of different management strategies have been performed using the simulation package and are reported and discussed in order to present the track followed to select the final design. Index Terms - Diesel generating set, energy savings, hybrid generation systems, logistical models, renewable sources, wind turbine.

The paper presents a new direct self-control (DSC) scheme for induction motor drives using the stator voltage third harmonic component in order to estimate the air-gap flux and the torque as well as to synchronize the supply voltage vector. Compared to previous DSC schemes the new one is independent from any motor parameter variation, specifically on stator resistance thus showing better performances at low speeds. The paper starts with a quick review on standard DSC main features pointing out the influence of stator resistance variations on the flux and torque control. The new DSC scheme is then introduced and evaluated by simulations and experimental tests on a 1.5-kW induction motor drive. Index Terms - Direct self control, induction motor drives, sensorless torque control.

MOSFET's and insulated gate bipolar transistor (IGBT) devices are increasingly used in electronic circuits due to both their easy driving and ability to handle high currents and voltages at high-switching frequencies. This paper deals with a new driver technique that allows optimization of the switching speed, reduction of the energy losses during the switching time, and limitation of the electromagnetic interference (EMI). First, an analysis of voltage- and current-switching waveforms of gate-insulated devices is performed. Then, a method of controlling voltage and current slopes independently is shown using the 'one-cycle' method or a suitable adaptive-driving technique based on a phase-locked loop (PLL) approach. These techniques were adopted in order to allow correct generation of the gate signals regardless of the operating conditions. Finally, practical results of the proposed driving circuit obtained using a single IGBT switch chopper are presented. Index Terms - Device-switching transients, driver circuit, insulated gate devices, Miller-effect detection.

In the present paper an approach is presented to the speed control of permanent magnet synchronous motors without mechanical transducers. The rotor position, which is an essential component of any vector control scheme, is calculated through the instantaneous stator flux position and an estimated value of the load angle. A closed-loop state observer is implemented to compute the speed feedback signal. Experimental results on a laboratory tested motor drive are presented to validate the proposed procedure.

Featured Application: The proposed circuit model is able to foresee the overall current distortion of different lamp configurations. This feature is very useful in the optimal design of lighting systems when a key target is the mitigation of the current distortion due to the power converter inside the energy-saving lamps. Energy-saving lamps are equipped with converters enabling high energy efficiency at the cost of injecting very distorted currents on the mains. The problem is more complex in the emerging smart-lighting scenario where these lamps are also used to perform additional tasks. Harmonics mitigation at the lamp level is expensive; consequently, an optimal lighting system design aiming at reducing both costs and current distortion of the whole lighting system is necessary. A tool able to emulate the current drawn from the lamps is necessary for optimal design. Such a tool has also to consider the fluctuations of the voltage on the mains that usually occur throughout the day. In this perspective, a parametric PSpice circuit is proposed and the netlist is reported in this work. Moreover, the simple procedure to be adopted for computing the parameters is also described. The validation has confirmed the ability of the proposed circuit in emulating the current drawn from various CFLs and LED lamps under different supplying voltage. [ABSTRACT FROM AUTHOR]

In the field of power electronics, the use of series-connected insulated gate devices, such as insulated gate bipolar transistors or power MOSFETs, is interesting in order to obtain fast and efficient power switches in medium-range power converters. In this kind of application, the control of the voltage sharing across the series strings of devices is an important aspect to be considered. The proposed technique allows obtaining safe commutations of the switches by simple and effective control circuits acting on the gate side of the power devices. In particular, the gate drive units are arranged in order to ensure good performance during the switching transients, while preventing overvoltage peaks on the devices. Both the design criteria and analysis of the control circuit are developed. Several experimental tests are reported in order to demonstrate the validity and correctness of the proposed approach. Index Terms--Gate drives, insulated gate bipolar transistor, MOSFETs, series connection.

Insulated gate devices, such as metal oxide semiconductor field effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs), are increasingly used in high-voltage power converters where a request for fast power switches is growing. Series connection of devices is a viable approach to manage voltages higher than the blocking voltage of the single device. The main problem in such an application is to guarantee the voltage balance across the devices both in steady-state and during the switching transients. In this paper a novel approach is presented, which is used to equalize the voltage sharing during the switching transients. The main advantages of the proposed method consist in avoiding the traditional use of the snubber capacitors, in the output power side, and in working on the gate side. The application of the proposed gate drive technique is firstly discussed and compared with different solutions, hence, validated by experimental tests applied to the control of series connected devices. Finally, a comparison is performed between the transient behaviors of two different configurations: a single switch with high-voltage blocking capability, and in alternative a series of two devices which together ensure the voltage blocking capability of the single switch. The better performances of the latter configuration, working with the proposed control circuit, over the former have been experimentally demonstrated. Index Terms--Active clamp, driving circuit, insulated gate bipolar transistor, MOSFET, series connection.

Integrated power electronics modules (IPEMs) represent an innovative typology of power electronics assemblies able to guarantee several advantages such as increasing of power density, better management of the thermal flows, and a significant reduction of the package sizes. Their characteristics make them suitable for applications like motor drives or power conditioning. IPEM usage in emerging fields like hybrid automotive traction and electric generation from renewable energy sources is continuously increasing. In this paper, we describe the implementation of a devised flow to generate the layer-based electrothermal PSpice model of an IPEM and the simulation flow of the model. The proposed modeling methodology allows reducing an electrothermal multidomain problem to an electrical single one. The general PSpice-like nature of the proposed model makes it suitable for a wide range of simulation frameworks where the integration of heterogeneous multiphysics models could be a difficult task. The outlining of both electrical and thermal PSpice layers is discussed, and the implementation into the final model, by the assistance of custom electronic-design-automation flow, is presented. Moreover, we describe the validation procedure of the proposed approach, and the results are compared with the ones obtained by a commercial finite-element-based package used as a benchmark. Two simulation approaches related to specific conversion systems, and related issues, are presented and discussed. [ABSTRACT FROM PUBLISHER]

In this paper, a physical model for a SiC Junction Field Effect Transistor (JFET) is presented. The novel feature of the model is that the mobility dependence on both temperature and electric field is taken into account. This is particularly important for high-current power devices where the maximum conduction current is limited by drift velocity saturation in the channel. The model equations are described in detail, emphasizing the differences introduced by the field-dependent mobility model. The model is then implemented in Pspice. Both static and dynamic simulation results are given. The results are validated with experimental results under static conditions and under resistive and inductive switching conditions. [ABSTRACT FROM AUTHOR]

Nowadays, LED lamps have become a widespread solution in different lighting systems due to their high brightness, efficiency, long lifespan, high reliability and environmental friendliness. The choice of a proper LED driver circuit plays an important role, especially in terms of power quality. In fact, the driver controls its own input current in addition to the LED output current, thus it must guarantee a high power factor. Among the various LED drivers available on the market, the quasi-resonant (QR) flyback topology shows interesting benefits. This paper aims at investigating and analyzing the different issues related to the input current distortion in a QR flyback LED driver. Several effects, such as the distortion caused by the ringing current, crossover distortion due to transformer leakage inductance and crossover distortion due to the input storage capacitor have been experimentally reported. These effects, not previously studied for a high power factor (Hi-PF) QR flyback, have been analyzed in depth. Finally, some practical design guidelines for a Hi-PF QR flyback driver for LED applications are provided. [ABSTRACT FROM AUTHOR]

• Equivalent circuit able at emulating the current drawn by any LED light bulb. • Any lamp in the market can be treated as a black-box to obtain the components. • Simple rules and equations to obtain the components of the equivalent circuit. • The change in the current drawn due to the variation of the network voltage is considered. • The validation shown a good matching between the simulated and measured waveforms. In lighting system design, the LED light bulb technology is gaining more and more advantages in comparison to other previous solutions. On the other hand, the designers of lighting systems have to face the specific problems created by this technology in terms of deterioration of the power quality on the mains. The knowledge of lamp electrical models is a key point for the optimal design of the lighting systems but such models are not provided by the manufactures. Moreover, the voltage on the mains may vary along the day due to the load fluctuation as well as due to the variation of the power generated by distributed renewable resources. Consequently, suitable electrical models have to be able at emulating the lamp behavior according to the voltage variability. The paper proposes an equivalent electrical circuit of LED light bulb. The components of the model are identified by means of simple electrical measurements. In particular, the circuit enables to emulate the current waveform in the case of network voltage variability. The validation has highlighted that the simulated currents waveforms have a good matching with the experimental data obtained in presence of distorted voltage on the mains (provided that the voltage THD is compliant with IEEE-Std-519). The validation has been performed also at voltage values different from the ones used for the components identification. [ABSTRACT FROM AUTHOR]