2002 IEEE 33rd Annual IEEE Power Electronics Specialists Conference. Proceedings (Cat. No.02CH37289)

This paper presents a single-phase three-wire (1/spl phi/3W) grid-connection photovoltaic (PV) power inverter with a feature of a partial active power filter (PAPF), which can not only deal with PV power but can filter current harmonics and improve power factor. Once the processed power exceeds the switch ratings, the inverter can reduce its output reactive power and harmonic power, while still can supply the maximum real power generated by the PV arrays. In derivation of control laws, a limit circle is defined to confine the output power of the inverter. To determine the power that the inverter can process, a criterion is proposed to find reactive power, which can avoid complex detections of phase angle and magnitude of the fundamental component of a nonlinear load current. Simulation results and experimental measurements have verified the proposed algorithm and the feasibility of the inverter.

This paper describes the developments at the University of Minnesota of new approach in teaching of electric drives, focusing on the associate state-of-the-art laboratory. The mission of these developments is to nationally revitalize courses in industrially and strategically vital fields of electric drives (and power electronics). This is accomplished by making these courses appealing to students (undergraduate enrollments have significantly increased subsequent to adopting these approaches) where they receive a first-rate education in just one undergraduate course in a way that ensures a seamless continuity to advanced courses. The laboratory is based on a dSPACE development board and several custom designed power converter boards and electric motors, working on a 42 V DC-bus voltage system.

This paper presents high voltage (HV) NMOS based level shifters, bootstraps and charge pumps in direct and cascaded topologies, which are highly useful to implement either power integrated circuits (PICs) high-side transistor floating drives or compact inductorless DC-DC power supplies. Monolithic solutions resorting to a unique HV NMOS switching cell are very important when standard CMOS technologies are intended to be used. In fact, these floating drives are fully CMOS compatible. Even while using a dedicated PIC technology this approach is a cost effective one. Furthermore, topologies based on a unique HV NMOS can be implemented in regular and simple geometry, thus, they are prone to be easily configured by top metal layers and to pave the way to mask configurable PICs. Simulation and experimental results obtained for a level shifter, a bootstrap and a charge pump used either as voltage multiplier or as a floating voltage source are presented and discussed. These low cost solutions are highly desirable for mobile applications power management and an efficient drive either for PICs or for intelligent devices.

In this paper, a low-power bidirectional DC/DC converter for inverter battery charger applications is considered. Initially, a galvanically isolated and synchronously rectified DC/DC converter topology is prototyped and its stationary performance evaluated. Next, a nonlinear dynamic model of the converter is derived using a state space averaging method. The dynamic model is nonlinear in the sense that it is a function of both converter duty cycle and load. The nonlinear model is then digitized and a proposed simulation algorithm derived and successfully validated against empirical data from the prototype converter. Finally, the large signal circuit dynamics are analyzed and an adaptive, fully digital pole placement controller is examined in adaptive and nonadaptive modes of operation.

This paper proposes a soft-switching cell, based on the concept of input voltage cancellation or switching input supply, performed with a resonant commutated pole at the input of any bridge converter. The proposed auxiliary switching cell permits soft switching in all bridge topologies (half bridge, full bridge and 3-phase), in any load conditions, even with bi-directional input current.

A detailed parameter extraction sequence for the comprehensive silicon carbide (SiC) power diode model Is presented. The extraction sequence Is applicable to any SiC diode technology. It is demonstrated for a 1.5 kV, 10 A merged PIN Schottky (MIPS); 5 kV, 20 A PiN; 10 kV, 5 A PiN; and the new commercially available 600 V, 1 A and 4 A Schottky diodes.

In this paper, the extended describing function (EDF) and the generalised averaging modelling techniques have been applied to a PRC-LCC resonant AC/DC power conversion topology with a capacitor as output filter. In this way, a mathematical large signal model has been obtained to describe the topology dynamic behaviour. This large signal model consists of a set of nonlinear differential equations which are solved numerically with the help of a computer. The resulting algorithm is faster than a straight PSpice simulation and free of convergence problems. From this dynamical model, a very simple steady state model has also been deduced. In the paper it is shown and particularised for the operation along the optimum switching tine. Finally, the accuracy of the presented models is verified with a wide set of experimental results.

This paper proposes a technique to determine the on-line stator resistance of a four-phase induction machine in a four-phase drive system. Besides the stator resistance, the stator leakage inductance can also be estimated. These parameters are obtained by solving a least squares minimization problem. The technique is conceived to be used on-line with the drive strategy without disturbing the machine electromagnetic torque. Experimental results are used to demonstrate the feasibility of the proposed technique.

A current sensor employing a Hall-based field sensing ASIC in combination with a current transformer is proposed. The sensor is characterized by a measuring range of /spl plusmn/50 A, an upper bandwidth limit of 20 MHz and high dV/dt-immunity up to 10 kV//spl mu/s. The sensor functional principle and dimensioning are discussed in detail. Parameters determining the sensor bandwidth are clarified, the theoretical considerations are verified by experiments. Finally, measures for further increasing the sensor bandwidth are proposed.

In this paper, a detailed analysis of the zero-voltage and zero-current-switching (ZVZCS) full-bridge PWM converters is performed. The differences of the zero-voltage-switching (ZVS) operation between the conventional ZVS full-bridge PWM converters and the ZVZCS full-bridge PWM converters are analyzed in depth. Circuit parameters that affect the soft-switching conditions are examined and the critical parameters are identified. Based on the analysis, practical design considerations are presented. The analysis and design considerations are verified by experimental results from a 630 V/4 kW converter operating at 80 kHz.