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D.A. Ganeshpure

13 records found

Authored

Design of Integrated Hybrid Configuration of Modular Multilevel Converter and Marx Generator to Generate Complex Waveforms for Dielectric Testing of Grid Assets

Journal article (2024) - D.A. Ganeshpure, Thiago Batista Soeiro, M. Ghaffarian Niasar, Nitish Milind Kulkarni, P. Bauer, P.T.M. Vaessen, P.T.M. Vaessen

This article proposes a new configuration of a modular multilevel converter (MMC) and a Marx generator to generate fast-rising impulse waveforms. This new configuration improves the capabilities of the MMC-based high voltage arbitrary wave shape generator to generate fast-risi ...

Design of a High Voltage Arbitrary Wave Shape Generator for Dielectric Testing

Doctoral thesis (2024) - D.A. Ganeshpure

The integration of wind and solar energy through power electronic converters has introduced new challenges to High Voltage (HV) equipment in the electrical power system. Switchgear, cables, and transformers are now subject to higher dV/dt stress and complex wave shapes due to solid-state switching. This poses a threat to the reliability of the grid by weakening the dielectric material of these assets. Existing HV test sources face limitations in generating complex wave shapes and have restricted current capabilities. Building a customized test setup is time-consuming when combining multiple HV test sources for complex waveforms. To overcome these challenges, an Arbitrary Wave shape Generator (AWG) for dielectric testing of HV grid assets is proposed. The Modular Multilevel Converter (MMC) topology is chosen for its modular structure, low harmonic content, and scalability to higher voltage levels. The initial focus is on dielectric testing of Medium Voltage (MV) class equipment, with the ultimate goal being the development of a modular prototype as part of a PhD project. HV test requirements and procedures for conventional tests of MV class equipment are compiled, along with specifications for non-standard wave shapes in consideration of the hybrid grid. Two main HV test requirements are addressed in the PhD thesis: the output voltage range of 10 kV to 100 kV with a load capacitance range of 50 pF to 10 nF and a large-signal bandwidth up to 2.5 kHz. The second requirement involves generating steep pulses with a rise time of a few microseconds for a voltage magnitude of 250 kV across a capacitive load of 10 nF. Despite the maturity of MMC technology for HVDC transmission, adapting it for HV AWG applications presents unique challenges. The thesis explores design trade-offs related to MMC parameters such as the number of Submodules (SMs) per arm, arm inductance, arm resistance, modulation technique, SM capacitance, and control system. Design criteria are developed and demonstrated through simulation models and a scaled-down prototype. The control hardware of the HV AWG is addressed using a commercially available Real Time Simulator (RTS) named Typhoon-HIL. This choice is based on its flexibility to program arbitrary waveforms in the FPGA without coding in any special hardware description language. The performance is demonstrated in the scaled-down prototype, achieving sinusoidal waveforms up to 5 kHz reference frequency with THD less than 5%. The second HV test requirement, steep pulse generation, is investigated with the MMC topology. It is found that the series-connected SMs of MMC make it challenging to obtain a short rise time across a large capacitive load. To address this, an integrated hybrid circuit of MMC and Marx generator circuit is proposed for complex waveforms with a rise time faster than 100 μs. Proper guidelines for choosing circuit parameters are provided and experimentally validated with a scaled-down prototype.@en

Demonstration of Scalable Series-Connected Submodule of Modular Multilevel Converter-based Arbitrary Wave shape Generator used for High Voltage Testing from Off-the-Shelf Component

Journal article (2023) - D.A. Ganeshpure, Thiago B. Soeiro, Thiago B. Soeiro, Mladen Gagic, M. Ghaffarian Niasar, P. Bauer, P.T.M. Vaessen

To test high-voltage (HV) equipment with increasingly complex transients obtained from various power system studies, this article demonstrates a hardware implementation of a medium-voltage (MV) submodule (SM) to be used in a modular multilevel converter (MMC)-based HV arbitrary wave shape generator (AWG). The MV SM is scalable with its own onboard auxiliary power supply (APS), and it is constructed by connecting three full-bridge SMs in series from the commercially available component. The designed MV SM can be operated for a wide voltage range of 0.8-2.7 kV to incorporate different test objects ranging from HV insulation material to MV equipment and generate a wide output range of 0.12-1.2 kV. Considering the hardware nonidealities in the APS, gate driver, and switches, the series operation of three SMs is ensured using an arm energy controller. Based on the current-based model of APS, SM capacitance design criteria are updated for variable-frequency output waveform, and the minimum dc-link voltage is calculated for the proper start-up of this scalable MMC module. Apart from the variable voltage per SM, the HV AWG application poses different conditions, such as a low value of SM capacitance value and the HV dc sources with a current rating of a few tens of milliamperes. Hence, this article proposes exclusive design guidelines for the proper start-up, steady-state, and shutdown operation of the MMC-based AWG. In addition, this article dives deeper analytically into the soft start-up algorithm to understand its working principle and to design the average charging current within the limit for any number of SMs of the arm. In the end, their performance is showcased with a single MV SM per arm, operating at a different voltage (0.8-2.7 kV) and frequency levels (1-600 Hz) and generating different wave shapes, such as triangular, sinusoidal with different harmonics, and pulse waveforms. In addition, the fault ride-through capability is verified for the MMC-based HV AWG.

@en

The Control Stage of a Modular Multilevel Converter-based Arbitrary Wave shape Generator for Dielectric Testing of High Voltage Grid Assets

Conference paper (2023) - D.A. Ganeshpure, Thiago B. Soeiro, M. Ghaffarian Niasar, P.T.M. Vaessen, P.T.M. Vaessen

A Modular Multilevel Converter (MMC)-based Arbitrary Wave shape Generator (AWG) for High Voltage (HV) testing faces challenges in the control hardware to generate kHz-range high-frequency waveforms. Real Time Simulators (RTS) provide a simple way to implement the control of the M ...

Implementation of Active Damping Control Methodology on Modular Multilevel Converter(MMC)-Based Arbitrary Wave Shape Generator Used for High Voltage Testing

Conference paper (2023) - Xiaochuan Zhou, D.A. Ganeshpure, Thiago B. Soeiro, M. Ghaffarian Niasar, Y. Wu, P.T.M. Vaessen, P.T.M. Vaessen

In order to damp the resonance in the MMC-based Arbitrary Wave shape Generator (AWG) used for high voltage testing, an active damping control methodology is proposed in this paper instead of the passive damping with an arm resistor. It is vital to ensure the system’s stability wh ...

Partial Discharge Behavior of Typical Defects in Power Equipment under Multilevel Staircase Voltage

Journal article (2022) - Y. Zang, M. Ghaffarian Niasar, D.A. Ganeshpure, Yong Qian, Gehao Sheng, Xiuchen Jiang, P.T.M. Vaessen

With the widespread application of power electronic switching technology, power equipment is facing new electrical stresses brought about by multilevel staircase voltages during testing and operation. Therefore, the partial discharge (PD) behavior of five typical defects in po ...

Comparison of Pulse Current Capability of Different Switches for Modular Multilevel Converter-based Arbitrary Wave shape Generator used for Dielectric Testing of High Voltage Grid Assets

Conference paper (2022) - D.A. Ganeshpure, Ajeeth Phrassanna Soundararajan, Thiago B. Soeiro, M. Ghaffarian Niasar, P.T.M. Vaessen, P.T.M. Vaessen, P. Bauer

This article compares the pulse current capability of various Semiconductor (SM) device technologies for Modular Multilevel Converter (MMC)-based High Voltage (HV) Arbitrary Waveform Generator (AWG) for dielectric testing of grid assets to find the most suitable SM device technology which can perform well in generating lightning impulse that demands a high peak current for a relatively short time. For the typical HV loads of the AWG, Lightning Impulse (LI) test may require a pulse current to rise to 1.7 kA in 0.2 µs. It is essential to highlight that most other dielectric tests performed with an HV AWG demand a relatively low current such as less than 10 A. Therefore, TO-packaged semiconductors would be well-suited for a large number of tests other than short impulses. To optimize the size and cost of the HV AWG, this paper evaluates the pulse current capabilities of TO-packaged semiconductors for the above-mentioned current requirement to generate LI waveform. The first comparison is made among Non-Punch Through (NPT) Si IGBT, Field Stop (FS) Si IGBT, Si MOSFET, and SiC MOSFETs with roughly the same current rating of 40 A. It is found that the Si MOSFET gives the fastest rise time of 0.42 µs and the NPT IGBT gives the highest current amplification factor of almost 12 times greater than its own rated current. However, 3rd Generation SiC MOSFET combines Si MOSFET and NPT IGBT capabilities to generate a fast rise time and high peak pulse current. Additionally, the FS IGBT is compared with the SiC MOSFET. The SiC MOSFET performs better in peak current capability and the obtained rise time. All in all, the research results and the stringent HV AWG requirements for LI show that the application requires a relatively complex switch implementation with far superior current capability than in normal operation. Therefore, a parallel connection of several TO-packaged devices is necessary to generate LI from MMC-based HV AWG.@en

A Transformer Isolated Driving Method for SiC MOSFETs with a Constant Negative Off Voltage

Conference paper (2021) - G. Yu, M. Ghaffarian Niasar, D.A. Ganeshpure, Thiago B. Soeiro, P. Bauer

SiC MOSFETs have become more and more popular in recent years. Apart from its superior performance, attentions should be paid to its driving method. In this paper, an improved transformer driving circuit is proposed which can provide an almost constant negative turn-off voltage w ...

Design Trade-Offs of Modular Multilevel Converter-Based Arbitrary Wave Shape Generator for Conventional and Unconventional High Voltage Testing

Journal article (2021) - D.A. Ganeshpure, Thiago B. Soeiro, M. Ghaffarian Niasar, P.T.M. Vaessen, P.T.M. Vaessen, P. Bauer

This paper comprehensivelyinvestigates the design trade-offs of a Modular Multilevel Converter (MMC) operations as an Arbitrary Wave shapesGenerator (AWG) to perform High Voltage (HV) dielectric testing of different grid assets. HV AWG applications pose unique operatingconditi ...

Modular Multilevel Converter-based Arbitrary Wave shape Generator used for High Voltage Testing

Conference paper (2021) - D.A. Ganeshpure, Thiago B. Soeiro, M. Ghaffarian Niasar, P.T.M. Vaessen, P.T.M. Vaessen, P. Bauer

This paper analyses different design trade-offs for a Modular Multilevel Converter (MMC)-based Arbitrary Wave shape Generator (AWG) used for High Voltage (HV) testing and certification of grid assets such as transformers, switchgear, and cables. Modulation techniques, number of s ...

Analysis of Partial Discharge Behaviour under Staircase-based Sinusoidal Voltage Waveforms

Conference paper (2021) - D.A. Ganeshpure, L.C. Castro Heredia, M. Ghaffarian Niasar, P.T.M. Vaessen, P.T.M. Vaessen, Thiago B. Soeiro, P. Bauer

This paper presents a comparison in Partial Discharge (PD) behaviour when an air corona setup is subjected to different waveforms, namely an idealized 50 Hz sinusoidal and staircase-based sinusoidal waveforms near inception voltage and at a higher voltage. In this study, it has b ...

Contributed

Investigation of Pulse current capabilities of IGBTs and MOSFETs

Master thesis (2021) - A.P. Soundararajan, Thiago B. Soeiro, D.A. Ganeshpure, A. Shekhar, A. Lekić

TU Delft and KEMA laboratories are collaborating to create a Programmable high voltage test source by employing Modular Multilevel Converter MMC which can generate output voltage waveforms of any arbitrary shape. To produce an Impulse waveform of magnitude 250 kV across a capacitive load of 10 nF with a rise time of 1.2 µs as output voltage, each Power Electronic device incorporated into each Sub-Module of the MMC has to conduct pulse currents as high as 850 Amperes. Moreover, the Impulse Waveform has a very short time duration. Hence the Power Electronic devices need to conduct such high current magnitude only for a very short duration of time. This motivates this Master thesis to find out how many multiples of its rated current a Power Electronic device is able to conduct within such short time and what factor limits the peak current capability of the Power Electronic device. However, to produce an output voltage of any other waveshape each Power Electronic device of each Sub-Module of the MMC has to conduct only a few amperes of continuous current. Employing Power Electronic devices of current rating as high as pulse currents of Impulse waveform is not only uneconomical since other waveforms do not require such high continuous currents, but also such Power Electronic devices of high current rating would make the MMC bulkier.
To identify the Power Electronic device technology that is capable of conducting such high pulse currents, a literature review is conducted among IGBT, MOSFET and their types. Each device of IGBT and MOSFET is compared to one another. Finally, the most promising switching technology is chosen among MOSFET and IGBT based on three criteria namely, high peak current capability, high voltage blocking capability and high switching frequency.
A prototype of Pulse Current Test circuit is built to test the peak pulse current of the chosen switching technology. Then, the factors that can be utilized to achieve the peak pulse current are identified. Based on results of the pulse current test, the multiplication factor of the rated current of the Power Electronic device is identified. Switch technology for the MMC specifically for Impulse waveform is suggested.

Implementation of Control for MMC-Based Arbitrary Wave Shape Generator in the OPAL-RT Simulator

Master thesis (2021) - S.V. Subramaniam, Thiago B. Soeiro, D.A. Ganeshpure, Y. Wu

A High Voltage (HV) Modular Multilevel Converter (MMC) based Arbitrary Wave shape Generator (AWG) is to be designed for a final voltage of 100 kV with 67 submodules in each arm. They can be used to test unconventional stresses experienced by high voltage equipment. Before the realization of a full-scale prototype setup, it is necessary to validate the controller as it involves the complexity of communication and control of a large number of switches in the circuit while demanding accuracy in the generation of gate pulses. OPAL-RT was identified as a good solution for implementing the MMC control. This thesis intends to investigate two main objectives. Firstly, to evaluate the various capabilities of the OPAL-RT to implement control of MMC by performing simulations and testing it with real MMC with 12- submodules. Secondly, to design a PR controller for the MMC circuit and further validate it in real-time. The topology of MMC, as well as two modulation approaches – Phase-Shifted Carrier (PSC) and Nearest Level Control (NLC) were explored initially. This was followed by the filter design for 50 Hz and 1 kHz fundamental frequencies. Thereafter, the trade-offs for both control strategies based on the filter design requirement were examined. Furthermore, the various software tools included in OPAL-RT were investigated for potential use in the development of the control algorithm. To test the accuracy of gate pulses and the ability to generate precise waveforms for higher fundamental frequencies, Model-in-Loop testing with eFPGAsim is used. By realizing, the control algorithm in the CPU and the MMC in the FPGA, results obtained are compared with the offline simulations. It is observed that the minimum CPU time step is incapable of generating accurate waveforms for higher fundamental frequencies, resulting in missing or delayed gate pulses. Next, the control was implemented in the FPGA using internal PWM generators of the OPAL-RT and the MMC plant was tested both in the FPGA and as actual hardware. In PSC modulation, the phase shift between the upper and lower arm decides the switching pattern of the submodules, contributing to the building of the voltage level at any instant. In this case, the gate pulses’ phase difference between the lower and upper arms are noticed to be larger than what is observed from the offline simulations. These phase delays are resulting in the addition of delayed gate pulses at any instant causing strange switching voltage levels at the output, contributing to unexpected carrier harmonics. Furthermore, because the CPU samples the modulating signal before passing it to the FPGA for processing, it compensates for communication latency while also contributing to inaccuracy. Finally, a PR controller was designed and discretized for performing stability analysis, later implemented on the real-time setup. The PR controller resulted in suppressing the lower order harmonics by reducing them within the expected tolerance limits and the THD obtained was consistent with the results of the offline simulation.