B Arun Karuppaswamy

Bio: B Arun Karuppaswamy is an academic researcher from Indian Institute of Science. The author has contributed to research in topics: Inverter & System under test. The author has an hindex of 2, co-authored 3 publications receiving 16 citations.

A grid simulator to evaluate control performance of grid-connected inverters

Abstract: Grid simulators are used to test the control performance of grid-connected inverters under a wide range of grid disturbance conditions. In the present work, a three-phase back-to-back connected inverter sharing a common dc bus has been programmed as a grid simulator. Three phase balanced disturbance voltages applied to three-phase balanced loads has been considered in the present work. The developed grid simulator can generate three phase balanced voltage sags, voltage swells, frequency deviations and phase jumps. The grid simulator uses a novel disturbance generation algorithm. The algorithm allows the user to reference the disturbance to any of the three phases at any desired phase angle. Further, the exit of the disturbance condition can be referenced to the desired phase angle of any phase by adjusting the duration of the disturbance. The grid simulator hardware has been tested with different loads — a linear purely resistive load, a non-linear diode-bridge load and a grid-connected inverter load.

A thermal enclosure model for inverters

Abstract: Design of a suitable thermal model, inclusive of the enclosure or cabinet, is an integral part of power electronic thermal management. This stems from the fact that power losses in an inverter may cause severe temperature rise in the enclosed cabinet, causing damage to the inverter switches or components. A thermal enclosure model for a 3φ, back-to-back inverter topology rated 24 kVA, kept in an enclosure having dimensions 1.524 × 1.066 × 1.828 cubic metre is presented. An enclosure air temperature calculation algorithm has been proposed to calculate the enclosure air temperature in steady state when power losses in the inverters and enclosure material and dimensions are the only known parameters. Effects of the enclosure air temperature on the heat-sinks and switches of the back to back inverter have also been investigated for the above mentioned inverter topology. The enclosure air temperature is calculated with an error less than 3%.

A novel thermal performance evaluation method for inverter passive components

Abstract: Improvement in the reliability of grid-connected inverters is desirable with their increasing use Inverter reliability tests usually focus on thermal testing of semiconductor devices Regenerative methods are adopted to minimize the energy consumed during these tests Regeneration requires additional systems — converters or passive components In this paper, a novel method for thermal testing of the passive components associated with a grid-connected inverter is proposed The method can be used to test the output filter inductors, output ac filter capacitors and input dc electrolytic capacitors Thermal stress affects the working life of capacitors and can cause insulation failure in inductors Thermal testing of these passive components, besides the semiconductor device thermal testing, contributes to improved reliabilty of the grid-connected inverter system Unlike regenerative methods that require additional systems of high-power rating, the proposed method circulates rated current within the three legs of the inverter under test The only additional system required is a low power dc supply with variable output voltage The variable dc input supplies the losses in the system under test The applicability of the proposed test for both three-wire and four-wire grid-connected inverter systems is discussed

Heat and Mass Transfer

Abstract: Thermophysical Properties Research Literature Retrieval Guide Edited by Y. S. Touloukian, J. K. Gerritsen and N. Y. Moore Second edition, revised and expanded. Book 1: Pp. xxi + 819. Book 2: Pp.621. Book 3: Pp. ix + 1315. (New York: Plenum Press, 1967.) n.p.

High-Performance Grid Simulator Using Parallel Structure Fractional Repetitive Control

Abstract: In this paper, a high-performance grid simulator based on a parallel structure fractional repetitive control scheme is employed to emulate various operation scenarios of power grids for testing power products In this paper, a simple fractional repetitive control scheme is proposed for grid simulators to achieve high-accuracy tracking performance Using parallel branches, the proposed repetitive controller can flexibly select the interested harmonics for compensation, and independently, tune the convergency rate at selective harmonic frequencies Compared with the conventional repetitive control, the proposed control scheme achieves faster transient response Moreover, the number of delay units required in the proposed repetitive controller is reduced to at least half of that in a conventional repetitive controller Design process and stability criteria are presented in details A set of experimental results is provided to verify the effectiveness of the proposed approach

Distributed Generation Grid-Connected Converter Testing Device Based on Cascaded H-Bridge Topology

Abstract: This paper presents the configuration, control, and implementation of a testing device to check the reliability of a high-voltage high-power distributed generation (DG) grid-connected converter. The device employs the cascaded H-bridge topology and generates abnormal voltages (AVs), i.e., voltage amplitude–frequency deviation, voltage fluctuation, and voltage unbalance that are associated with a typical power grid. A unified rms value feedback control (URFC) in the stationary frame (SF) is adopted, which has the advantages of a higher precision, an easier selection of controller parameters, and a higher reliability, compared with other existing control approaches in either synchronous reference frame or SF. The feasibility and effectiveness of the proposed design concept of a DG grid-connected converter testing device (DGCTD) are validated by the real-world industrial field experiments performed on the “35 kV–6 MW testing device,” under both no-load and load conditions.

Auxiliary subsystems of a General-Purpose IGBT Stack for high-performance laboratory power converters

Abstract: A PWM converter is the prime component in many power electronic applications such as static UPS, electric motor drives, power quality conditioners and renewable-energy-based power generation systems. While there are a number of computer simulation tools available today for studying power electronic systems, the value added by the experience of building a power converter and controlling it to function as desired is unparalleled. A student, in the process, not only understands power electronic concepts better, but also gains insights into other essential engineering aspects of auxiliary subsystems such as start-up, sensing, protection, circuit layout design, mechanical arrangement and system integration. Higher levels of protection features are critical for the converters used in a laboratory environment, as advanced protection schemes could prevent unanticipated failures occurring during the course of research. This paper presents a laboratory-built General-Purpose IGBT Stack (GPIS), which facilitates students to practically realize different power converter topologies. Essential subsystems for a complete power converter system is presented covering details of semiconductor device driving, sensing circuit, protection mechanism, system start-up, relaying and critical PCB layout design, followed by a brief comparison to commercially available IGBT stacks. The results show the high performance that can be obtained by the GPIS converter.