Antonio Ginart

Wireless power transfer (WPT) via magnetic resonance coupling is considered a promising outlet for electric vehicle (EV) charging due to the noncontact method. Unlike a traditional transformer, with WPT, the relative spacing and lateral distance between the primary and secondary coils are highly variable, which can affect the wireless power delivery and lower the efficiency. A magnetic positioning approach that shares the wireless charging structure is proposed to solve the misalignment issue… Show more

Wireless power transfer (WPT) via magnetic resonance coupling is considered a promising outlet for electric vehicle (EV) charging due to the noncontact method. Unlike a traditional transformer, with WPT, the relative spacing and lateral distance between the primary and secondary coils are highly variable, which can affect the wireless power delivery and lower the efficiency. A magnetic positioning approach that shares the wireless charging structure is proposed to solve the misalignment issue associated with wireless EV charging. The proposed alignment sensing system employs multiple auxiliary minor coils on the secondary side to position the charging pad. The positioning principle and equivalent circuit were analyzed. The 108 samples were tested and they were distributed throughout the detection range of 70 cm. The experimental results demonstrate that >92% of those samples have positioning errors of <;2 cm and 98% of them have positioning errors of <;3 cm. Show less

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Solar inverters are designed specifically to handle photovoltaic (PV) panels, to efficiently extract the most amount of power, and to transform it properly so that it can be injected into the grid. The singularities of the application allow for opportunities that can be exploited for better performance. Inverters for PV applications are designed to operate at very low voltage variations,… Show more

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Solar inverters are designed specifically to handle photovoltaic (PV) panels, to efficiently extract the most amount of power, and to transform it properly so that it can be injected into the grid. The singularities of the application allow for opportunities that can be exploited for better performance. Inverters for PV applications are designed to operate at very low voltage variations, almost at a fixed frequency, and with a power factor usually greater than 0.8. While keeping these inverter-specific characteristics in mind, a new topology is proposed. In this work, such new topology provides operational characteristics close to a 5-level topology. This achievement is accomplished by adding just a few more power-electronic components required for a 3-level topology. A complete 3-phase system is designed and simulated. Its good performance is demonstrated, and its benefits and limitations are pointed out. Furthermore the feasibility of this new topology is also explored and verified by implementing a low-power inverter system with the proposed topology.
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This paper proposes a method that allows the operation with direct torque control under incipient faults of the power switching devices in single dc-link dual inverters. Once the fault onset of the switching device is detected, the troubled devices are put under trigger suppression to regain operation. The proposed control algorithm makes use of additional states, termed opportunistic states, to maintain control of the induction machine. Simulations and experimental results confirm the… Show more

This paper proposes a method that allows the operation with direct torque control under incipient faults of the power switching devices in single dc-link dual inverters. Once the fault onset of the switching device is detected, the troubled devices are put under trigger suppression to regain operation. The proposed control algorithm makes use of additional states, termed opportunistic states, to maintain control of the induction machine. Simulations and experimental results confirm the capabilities of the technique for up to six devices under trigger suppression. Show less

In this paper, effects preceding a latch-up fault in insulated gate bipolar transistors (IGBTs) are studied. Primary failure modes associated with IGBT latch-up faults are reviewed. Precursors to latch-up, primarily an increase in turn-off time as a consequence of elevated junction temperature, are examined for an IGBT. The relationship between junction temperature and turn-off time is explained by modeling the parasitic properties of an IGBT. A metric is derived from the model to standardize… Show more

In this paper, effects preceding a latch-up fault in insulated gate bipolar transistors (IGBTs) are studied. Primary failure modes associated with IGBT latch-up faults are reviewed. Precursors to latch-up, primarily an increase in turn-off time as a consequence of elevated junction temperature, are examined for an IGBT. The relationship between junction temperature and turn-off time is explained by modeling the parasitic properties of an IGBT. A metric is derived from the model to standardize the relative estimates in junction temperature from measurements of turn-off time. To evaluate the effects preceding latch-up in-situ, seeded fault testing is conducted on a three-phase power inverter using aged transistors induced with a fault located in the die-attach solder layer. Experimental results demonstrated the feasibility of using the proposed metric as a precursor to transistor latch-up. Show less

A fault-accommodation technique proposed for inverter drive systems extends the operation of an electrical power drive during an incipient power transistor fault. The discussed technique utilizes diagnostic methods to identify and isolate degraded power transistors. Once isolated, an appropriate fault-accommodating control method using one-transistor trigger suppression control relieves electrical overstress being applied to the degraded transistor to maintain motor operation, thus avoiding an… Show more

A fault-accommodation technique proposed for inverter drive systems extends the operation of an electrical power drive during an incipient power transistor fault. The discussed technique utilizes diagnostic methods to identify and isolate degraded power transistors. Once isolated, an appropriate fault-accommodating control method using one-transistor trigger suppression control relieves electrical overstress being applied to the degraded transistor to maintain motor operation, thus avoiding an inverter failure. Simulations and experimental tests demonstrate the feasibility of the proposed method for motor start-up even with a suboptimal control technique of constant V/f type. Also discussed are advantages and potential drawbacks of this technique. Show less

Embeddable features that are easily incorporated in traditional power drive systems are identified for prognostics and health management (PHM) systems. The proposed novel feature takes advantage of the original pulsewidth modulation (PWM) waveform produced by the inverter that is already available in the system as a succession of step functions to study the system's response at high frequencies. The high-order oscillatory responses (ringing) present in the voltages and currents of the system… Show more

Embeddable features that are easily incorporated in traditional power drive systems are identified for prognostics and health management (PHM) systems. The proposed novel feature takes advantage of the original pulsewidth modulation (PWM) waveform produced by the inverter that is already available in the system as a succession of step functions to study the system's response at high frequencies. The high-order oscillatory responses (ringing) present in the voltages and currents of the system are a reflection of the interaction among the internal parametric components of the power devices, allowing device characterization. Evaluating the change over time of these parameters characterized from ringing becomes a key novel feature to assess the aging status of the power electronic circuit and electric machine with respect to transistor degradation. We propose the use of a low-cost bandpass analog filter centered at a high frequency, which is relevant as a feature input capable of aging tracking. The simplified model supporting ringing as a feature to evaluate component aging and its experimental evaluation are presented with experimental data, corroborating its viability as a practical real-time power device health-state indicator. Show less

Real-time monitoring of power quality requires extensive data-handling and data-processing capabilities. These requirements limit the scope of monitoring, despite the fact that microprocessor-based monitoring systems have seen significant increase in their storage and computational power. Development of compact algorithms will benefit power quality in two ways; they will allow monitoring of more points simultaneously for large systems, and they will help create powerful embeddable monitoring… Show more

Real-time monitoring of power quality requires extensive data-handling and data-processing capabilities. These requirements limit the scope of monitoring, despite the fact that microprocessor-based monitoring systems have seen significant increase in their storage and computational power. Development of compact algorithms will benefit power quality in two ways; they will allow monitoring of more points simultaneously for large systems, and they will help create powerful embeddable monitoring architectures within small power devices, such as a breaker, motors, or power drives. This paper proposes use of the distance L1 norm as an indicator of power quality. We show how this approach will improve the computational and storage requirements. This work presents analyses of the proposed norm, how it compares with traditional approaches, and examples of its applications. Show less

This paper presents work on the development of a robust online digital electronic health management system. The presented technical approach integrates collaborative diagnostic and prognostic techniques from engineering disciplines, including statistical reliability, damage accumulation modeling, physics-of-failure modeling, signal processing and feature extraction, and automated reasoning algorithms. The prognostic and health management (PHM) approach is based on a paradigm of minimally… Show more

This paper presents work on the development of a robust online digital electronic health management system. The presented technical approach integrates collaborative diagnostic and prognostic techniques from engineering disciplines, including statistical reliability, damage accumulation modeling, physics-of-failure modeling, signal processing and feature extraction, and automated reasoning algorithms. The prognostic and health management (PHM) approach is based on a paradigm of minimally invasive onboard monitoring paired with model-based estimates to deliver timely and accurate health assessments. Show less

Combinations of analog and switching techniques have led to the development of audio power amplifiers capable of producing low distortion with high efficiency. The high efficiency is achieved with a combination of an inverter and an analog amplifier, where the inverter provides the power, and the analog amplifier acts as an active filter to correct distortion. In this paper, a full analysis of the system is presented using the hysteresis describing function approach to model the inverter. The… Show more

Combinations of analog and switching techniques have led to the development of audio power amplifiers capable of producing low distortion with high efficiency. The high efficiency is achieved with a combination of an inverter and an analog amplifier, where the inverter provides the power, and the analog amplifier acts as an active filter to correct distortion. In this paper, a full analysis of the system is presented using the hysteresis describing function approach to model the inverter. The set of equations obtained allows the description of the nonlinear behavior of the system, such as the limit cycle of the output voltage and its dependency on the hysteresis. The theoretical development also provides the relation between the switching frequency and the system parameters. The derived equations are verified and compared using PSpice simulations. Show less

A control strategy is proposed for AC thyristor controllers. The main feature of the proposed technique is that motors can start with high torque, while using an economical design. This allows the use of AC thyristor controllers for a wide range of applications, where they have not been used before. The method employs the AC thyristor controller as a discrete frequency inverter that increases the frequency until the frequency of the line is reached (60 Hz in this case). These discrete… Show more

A control strategy is proposed for AC thyristor controllers. The main feature of the proposed technique is that motors can start with high torque, while using an economical design. This allows the use of AC thyristor controllers for a wide range of applications, where they have not been used before. The method employs the AC thyristor controller as a discrete frequency inverter that increases the frequency until the frequency of the line is reached (60 Hz in this case). These discrete frequencies produced by the control are sub-multiples of line frequency. They are generated by omission or inclusion of line frequency half cycles. Voltage sequences are predefined for each sub-multiple of line frequency. In order to obtain positive torque for all these frequencies, the system is unbalanced. The proposed control is simulated (using EMTP), and built. Comparisons are done with the traditional AC thyristor starter. Results show reduced RMS starting current, increased starting torque and the possibility to operate at low speeds Show less

The steady-state and dynamic operation of a novel stand-alone, single-phase induction generator scheme is presented in which the load voltage and frequency are controlled by a single-phase, full-bridge, bipolar pulse-width modulated DC/AC inverter. A battery feeding the inverter supplies real power to the generator when the load demand is greater than the power supplied by the prime mover. When the real power supplied by the turbine exceeds the load demand, the excess power charges the battery.… Show more

The steady-state and dynamic operation of a novel stand-alone, single-phase induction generator scheme is presented in which the load voltage and frequency are controlled by a single-phase, full-bridge, bipolar pulse-width modulated DC/AC inverter. A battery feeding the inverter supplies real power to the generator when the load demand is greater than the power supplied by the prime mover. When the real power supplied by the turbine exceeds the load demand, the excess power charges the battery. The reactive power requirement is effectively met by the inverter with a shunt capacitor connected across the load. Experimental results obtained from the generator, feeding an impedance load, show that the generator scheme has excellent performance characteristics Show less

Induction Motor Model for PSPICE software