 |
 |
EPE Journal Volume 23-1 - Papers
- Isolated Zero-Voltage-Switching DC-DC Converter with High Voltage Gain
- Inverter Configuration for Simultaneous Dual Frequency Induction Hardening with Independent Control
- Fault Tolerant Operation of Power Converter with Cascaded Cells
- Upgrade of the NSRRC Booster Power Supply
- Development of a Modular High-Power Converter System for Battery Energy Storage Systems
EPE Journal Volume 23-1 - Editorial
By Juha Pyrhönen; Jarmo Partanen; Jero Ahola; Braham Ferreira
We are proud to announce that the 16th Conference on Power Electronics and Applications, EPE’14-ECCE Europe, will discover the Nordic latitudes and visit Lappeenranta, the home city of Lappeenranta University of Technology, on the border between the EU and Russia, and surrounded by the magnificent nature of the Finnish Lake Saimaa. Hosted by Lappeenranta University of Technology, the EPE’14-ECCE Europe conference will take place in a peaceful Nordic late-summer atmosphere from 26 to 28 August 2014. We hope to welcome a truly international academic and industrial audience, and invite you into the heart of Finnish expertise in Power Electronics.
EPE Journal Volume 23-1 - Papers
By Do, Hyun-Lark
An isolated zero-voltage-switching (ZVS) DC-DC converter with high voltage gain is proposed in this paper. In the proposed converter, two conceptually identical DC-DC converters are merged. To obtain high voltage gain, the output stages of two converters have voltage doubler structure and they are serially connected. An active clamp circuit is adopted to clamp the switch voltages and obtain ZVS operation of the switches. Thus, the switching losses are reduced. Moreover, the output diode currents are controlled by the transformer leakage inductances and the reverse-recovery problem of the output diodes is significantly alleviated. Due to the voltage doubler structure and the serial connection of the output stages, the voltages across the output diodes are confined to half of the output voltage. Steady-state analysis and experimental results for the proposed converter are also presented.
By S. Porpandiselvi; N. Vishwanathan
Induction hardening is a heat treatment process which selectively heats parts of work-piece with different size and shape. Components like gears require different frequencies with inner core requiring low frequency and outer surface requiring high frequency. Simultaneous application of low and high frequency currents is desirable for proper hardening of gear. This paper proposes a two inverter topology with a load resonant circuit which can provide independent and simultaneous control of low and high frequency currents through the load coil. The load circuit is a combination of two series resonant circuits which operates at the desired low and high frequencies. Power control is achieved with phase modulation of low and high frequency inverters.
By Frans Dijkhuizen; Staffan Norrga
In the field of high power electronics for transmission applications there is currently a strong tendency towards using modular converter topologies employing cascaded cells.These multilevel converters are well suited for high power applications, due to good control performance, extensive modularity and excellent harmonic distortion. This paper concerns fault tolerance of such a cascaded converter on cell level, and a method is proposed to exclude a cell from the chain of cells in case a semiconductor switching device fails. The described method concerns a semiconductor device in presspack encapsulation that normally fails into a permanent short circuit. In particular, it is applicable to converters that use Integrated Gate Commutated Thyristors (IGCT). The application of the converter considered here is STATCOM, where several tens or even hundreds of these cells are involved. Hence, a failure in one of the applied semiconductor switching devices should not lead to a malfunction of the whole converter. A feasible method for shorting out a failed cell is proposed and experimentally validated by two consecutive tests. The principle is to initiate a shoot-through in a cell hence discharging the DC cell capacitance completely where the circuitry for di/dt-reduction during turn-on limits the surge current. Hereby the used semiconductor switching devices are put into a permanently shorted state without using additional hardware. From the observations it can be concluded that the surge leads to a stable SCFM process (Short Circuit Failure Mode) which can conduct the converter current in both directions. The test is not fully conclusive as to how long the SCFM can be sustained. However, experiences from thyristors used in HVDC applications indicate that the SCFM state can be relied on to last for several years.
By Chen-Yao Liu; Kuo-Bin Liu; Yao-Ching Hsieh; Alexander Elkiær; Din-Goa Huang
For the 1.5GeV energy injector upgrade project for the NSRRC synchrotron light source, new ramping power supplies were implemented in the “White circuit” booster synchrotron ring. IGBT semiconductors operating at a higher frequency was employed to replace the older GTO-based system. The new system enabled reduction of the current waveform harmonic distortions and thus improving the injection and extraction efficiency. The increased reliability increased blind power from circuit mistuning also ensures higher system uptimes. The measured dynamic range of the 10 Hz sine wave current output of the new ramping power supply is shown to be better than 75 dB with a total harmonic distortion (THD) less than 0.015 %. From the monitored beam current, the low THD dipole magnets current can greatly improve the stability of the booster beam current.
By Stephan Thomas; Marco Stieneker; Rik W. De Doncker
The integration of storage systems into the grid is becoming increasingly important due to the growing amount of volatile power sources. This paper shows a theoretical approach for designing a modular battery energy storage system (BESS) for medium voltage grids (Fig. 1). Typically, this system is scalable in power rated from 5 MW up to 100 MW with a storage capacity of several hours. The flexibility of power rating and energy capacity allows the set-up of BESS for versatile applications. Using power electronic building blocks (PEBBs) a converter for DC grids and AC grids can be built. In this paper, the chosen topology for the AC solution is the cascaded cell converter. The focus is to determine the optimum number of levels, the modulation technique to avoid microcycles of the batteries and to present the efficiency. A formula to calculate the parasitic capacitance of lead-acid batteries is shown and verified by measurements, which is important for the design of such a converter system. Moreover, a new charging strategy for LiFePO4 - the chosen battery technology for the proposed storage system - is introduced, which prolongs the battery's life, reduces the charging time and decreases the life cycle cost. The proposed charging strategy and battery technology compared to lead-acid batteries is also economically evaluated.
EPE Journal Volume 23-1: News
By B. Sneyers
Next to the regular peer reviewed papers selected out of the number of papers received from the Call for papers, attendees of the next EPE ECCE Europe conference will be invited to attend outstanding industrial sessions on the following topics:
– Power electronics enabling the grid of the future;
– Aeronautics challenges;
– E-mobility in the city: vehicles and infrastructure;
– Power electronics for railways.
The programme is being finalized.