The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
David Leggate - One of the best experts on this subject based on the ideXlab platform.
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Control of a PWM Voltage-Source Inverter in the Pulse-Dropping Region to Reduce Reflected-Wave Motor Overvoltage
IEEE Transactions on Industry Applications, 2013Co-Authors: Rangarajan M. Tallam, David LeggateAbstract:Pulsewidth modulation (PWM) ac drives generate high line-line motor voltage, up to twice dc bus voltage, due to the Reflected-Wave phenomenon. Under certain conditions, motor voltage greater than twice the dc bus voltage can occur, resulting in winding insulation failure. It is well known that by suitably adjusting the PWM pulse pattern, the occurrence of voltages greater than twice the dc bus voltage can be avoided, up to a certain maximum cable length; beyond which, output filters are typically used to limit peak motor voltage. It will be shown in this paper that when the inverter operates in the pulse dropping region, voltages greater than twice the dc bus voltage will occur, with existing methods for pulse pattern compensation. A method to adjust the PWM pulse pattern in the pulse dropping region to ensure the same Reflected-Wave performance as the linear PWM region is presented in this paper. Experimental results are provided to demonstrate the effectiveness of the proposed method.
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Control of PWM voltage source inverter in the pulse dropping region to reduce Reflected Wave motor over-voltage
2011 IEEE Energy Conversion Congress and Exposition, 2011Co-Authors: Rangarajan M. Tallam, David LeggateAbstract:PWM AC drives generate high line-line motor voltage, up to twice DC bus voltage, due to the Reflected Wave phenomenon. Under certain conditions, motor voltage greater than twice DC bus voltage can occur, resulting in winding insulation failure. It is well known that by suitably adjusting the PWM pulse pattern, the occurrence of voltages greater than twice DC bus voltage can be avoided, up to a certain maximum cable length, beyond which output filters are typically used to limit peak motor voltage. It will be shown in this paper that when the inverter operates in the pulse dropping region, voltages greater than twice DC bus voltage will occur, with existing methods for pulse pattern compensation. A method to adjust the PWM pulse pattern in the pulse dropping region to ensure the same Reflected Wave performance as the linear PWM region is presented in this paper. Experimental results are provided to demonstrate the effectiveness of the proposed method.
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Common-Mode Voltage Reduction PWM Algorithm for AC Drives
IEEE Transactions on Industry Applications, 2010Co-Authors: Rangarajan M. Tallam, Russel J Kerkman, David Leggate, Richard A. LukaszewskiAbstract:The impact of common-mode voltage (CMV) generated by pulsewidth modulation (PWM) ac drives on motor bearings is well known. Several algorithms for CMV reduction have been proposed in the literature. While a few algorithms assume ideal switching and fall apart when nonidealities like inverter dead time are considered, some others are effective only in a limited operating range of the drive. In this paper, a previously proposed algorithm is modified for practical implementation to include compensation for dead-time and Reflected-Wave motor overvoltage stress while still producing output voltage Waveforms with reduced common-mode content. Experimental results are provided to show the reduction in CMV over the entire operating range, with other performance attributes such as Reflected-Wave motor overvoltage that are identical to conventional space-vector PWM. The advantages of applying the algorithm to a fully regenerative ac drive are also demonstrated.
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Reflected Wave modeling techniques for pwm ac motor drives
Applied Power Electronics Conference, 1998Co-Authors: Gary L. Skibinski, J Pankau, Russel J Kerkman, David Leggate, D SchlegelAbstract:Reflected Wave transient voltages that are impressed on drive output cables and low voltage AC induction motors are simulated with an excitation source of steep fronted d/spl nu//dt pulse Waveforms from a pulse width modulated (PWM) voltage source inverter. Motivation for system simulation arises from a need to correlate Reflected Wave peak voltage and risetime with the dielectric insulation capability of both motor and cable. Simulations based on an accurate system model also allow investigation into the effects of changing wire gauge, motor HP, cable distance or addition of drive output filters. System parameters of the inverter, cable and motor model are investigated in detail. Special emphasis is given to the importance of modeling cable skin and proximity effects. Simulation, measured lab and field results are compared. The main objective of the paper is to propose a Reflected Wave building block model that uses existing software on the market, is simple, computationally fast, easily configurable, reasonably accurate and allows investigation with wide variation of system parameters.
Rangarajan M. Tallam - One of the best experts on this subject based on the ideXlab platform.
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Control of a PWM Voltage-Source Inverter in the Pulse-Dropping Region to Reduce Reflected-Wave Motor Overvoltage
IEEE Transactions on Industry Applications, 2013Co-Authors: Rangarajan M. Tallam, David LeggateAbstract:Pulsewidth modulation (PWM) ac drives generate high line-line motor voltage, up to twice dc bus voltage, due to the Reflected-Wave phenomenon. Under certain conditions, motor voltage greater than twice the dc bus voltage can occur, resulting in winding insulation failure. It is well known that by suitably adjusting the PWM pulse pattern, the occurrence of voltages greater than twice the dc bus voltage can be avoided, up to a certain maximum cable length; beyond which, output filters are typically used to limit peak motor voltage. It will be shown in this paper that when the inverter operates in the pulse dropping region, voltages greater than twice the dc bus voltage will occur, with existing methods for pulse pattern compensation. A method to adjust the PWM pulse pattern in the pulse dropping region to ensure the same Reflected-Wave performance as the linear PWM region is presented in this paper. Experimental results are provided to demonstrate the effectiveness of the proposed method.
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Control of PWM voltage source inverter in the pulse dropping region to reduce Reflected Wave motor over-voltage
2011 IEEE Energy Conversion Congress and Exposition, 2011Co-Authors: Rangarajan M. Tallam, David LeggateAbstract:PWM AC drives generate high line-line motor voltage, up to twice DC bus voltage, due to the Reflected Wave phenomenon. Under certain conditions, motor voltage greater than twice DC bus voltage can occur, resulting in winding insulation failure. It is well known that by suitably adjusting the PWM pulse pattern, the occurrence of voltages greater than twice DC bus voltage can be avoided, up to a certain maximum cable length, beyond which output filters are typically used to limit peak motor voltage. It will be shown in this paper that when the inverter operates in the pulse dropping region, voltages greater than twice DC bus voltage will occur, with existing methods for pulse pattern compensation. A method to adjust the PWM pulse pattern in the pulse dropping region to ensure the same Reflected Wave performance as the linear PWM region is presented in this paper. Experimental results are provided to demonstrate the effectiveness of the proposed method.
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Common-Mode Voltage Reduction PWM Algorithm for AC Drives
IEEE Transactions on Industry Applications, 2010Co-Authors: Rangarajan M. Tallam, Russel J Kerkman, David Leggate, Richard A. LukaszewskiAbstract:The impact of common-mode voltage (CMV) generated by pulsewidth modulation (PWM) ac drives on motor bearings is well known. Several algorithms for CMV reduction have been proposed in the literature. While a few algorithms assume ideal switching and fall apart when nonidealities like inverter dead time are considered, some others are effective only in a limited operating range of the drive. In this paper, a previously proposed algorithm is modified for practical implementation to include compensation for dead-time and Reflected-Wave motor overvoltage stress while still producing output voltage Waveforms with reduced common-mode content. Experimental results are provided to show the reduction in CMV over the entire operating range, with other performance attributes such as Reflected-Wave motor overvoltage that are identical to conventional space-vector PWM. The advantages of applying the algorithm to a fully regenerative ac drive are also demonstrated.
Balaji Narayanasamy - One of the best experts on this subject based on the ideXlab platform.
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Reflected Wave Phenomenon in SiC Motor Drives: Consequences, Boundaries, and Mitigation
IEEE Transactions on Power Electronics, 2020Co-Authors: Balaji Narayanasamy, Arvind Shanmuganathan Sathyanarayanan, Fang Luo, Cai ChenAbstract:In voltage source inverter-based motor drives, the fast switching speeds of the power devices result in the Reflected Wave phenomenon. Besides the overvoltages at the motor end, there are overcurrents at the inverter end. The overvoltages increase stress on the motor and cable insulation, and the overcurrents affect the power devices. Wide bandgap (WBG) devices have lower switching losses and enable high switching frequencies. However, the Reflected Wave phenomenon is more pronounced in converters using WBG devices and could potentially increase the switching losses. This article presents a comprehensive analysis of the influence of the Reflected Wave phenomenon on the switching characteristics of SiC devices in motor drives. Notably, the effect of undamped Reflected Waves and different cable lengths on both the inverter end and motor end is studied. The analysis and experiments in this article uncover that, depending on the switching instance, the undamped Reflected Wave causes up to a 30% increase or up to a 15% decrease in the switching losses. A 12% reduction in the switching losses is observed with no cable to up to 20-m long cable. The last part of the article presents the design tradeoffs involved in designing a dv/dt filter. Five different dv/dt filters are compared in terms of their impact on the switching losses, dv/dt at the load, filter loss, and damping time of the Reflected Wave. The L filter and the RLC filter have around a 9% reduction in switching losses. The L filter suffers from increased damping time and higher Reflected Wave magnitude, making it unsuitable for high switching frequency applications. Overall, L // R filter offers the lowest filters losses with a 6% reduction in switching loss, making it more suitable for WBG devices-based high-speed motor drives.
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impact of cable and motor loads on wide bandgap device switching and Reflected Wave phenomenon in motor drives
Applied Power Electronics Conference, 2017Co-Authors: Balaji Narayanasamy, Arvind S Sathyanarayanan, Amol Deshpande, Fang LuoAbstract:In inverter based motor drives, the fast switching speeds of the power devices result in over-voltage at the motor end. Corresponding to these over-voltages at the motor end, there are over-currents at the inverter end. While the over-voltage increases stress on motor and cable insulation, the load and the cable parasitics increases the switching loss of the power devices. These effects are more pronounced in converters using Wide Bandgap (WBG) devices because of the their faster switching speed. Previous works have only studied either over-voltages or currents in converters with low source impedance. In this paper, the effect of inductive source impedance on the Reflected Wave Phenomenon (RWP) is studied. The impact of different filter topologies (used to mitigate the RWP) on the switching losses of the devices. Also, the effect of the cable parasitic including the ground and shield wires are studied here. Experiments are carried out to identify losses in different filter topologies, RWP, switching losses of devices and dv/dt at the load.
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analysis and mitigation of Reflected Wave voltages and currents in wbg devices based motor drives
IEEE Workshop on Wide Bandgap Power Devices and Applications, 2016Co-Authors: Balaji Narayanasamy, Arvind S Sathyanarayanan, Amol Deshpande, Fang LuoAbstract:In inverter based motor drives, the fast switching speeds of the power devices along with the cable, result in overvoltage at the motor end. Corresponding to the overvoltage at the motor end, there are currents at the inverter end. While the overvoltage increases the stress on motor and insulation, the load parasitics along with the cable increases the switching loss of the power devices. These effects are more pronounced in converters using WBG devices because of faster switching times. Previous works have only studied either over-voltages & currents in 2-L converters. The 2-L converters have low source and high load impedances. This work involves the study of the effect of inductive source impedance and RC terminal network on the Reflected Wave phenomenon and the switching loss of the device. Simulation and experimental results are shown to verify the analysis.
David Ingram - One of the best experts on this subject based on the ideXlab platform.
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isolating incident and Reflected Wave spectra in the presence of current
Coastal Engineering Journal, 2018Co-Authors: Samuel Draycott, Jeffrey Steynor, Thomas Davey, David IngramAbstract:ABSTRACTIt is vital for a variety of coastal and ocean engineering problems to understand the reflection characteristics of structures and devices. Various methods have been developed for Wave-only cases, yet none have been demonstrated for Wave–current conditions present in both the laboratory and real sea environments. A simple method to isolate Wave reflections in collinear current is presented in this article, utilizing an established frequency-domain least-squares approach with a modified dispersion relation. The method has been tested numerically, before being applied to experimental data obtained at the FloWave Ocean Energy Research Facility. Typical Wave spectra are generated in currents ranging from −0.3 m/s to 0.3 m/s. Results obtained demonstrate the method effectiveness whilst verifying that the assumptions are valid. The development of this method should enable reflection analysis to be performed for Wave–current conditions with improved accuracy and greater confidence.
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isolating incident and Reflected Wave spectra in the presence of current
Coastal Engineering Journal, 2018Co-Authors: Samuel Draycott, Jeffrey Steynor, Thomas Davey, David IngramAbstract:It is vital for a variety of coastal and ocean engineering problems to understand the reflection characteristics of structures and devices. Various methods have been developed for Wave-only cases, ...
Annette Von Jouanne - One of the best experts on this subject based on the ideXlab platform.
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Control of Variable Frequency Drive PWM to Mitigate Motor Overvoltage Due to Double Pulsing in Reflected Wave Phenomenon
2018 IEEE Energy Conversion Congress and Exposition (ECCE), 2018Co-Authors: Han Xiong, Julia Zhang, Annette Von JouanneAbstract:It is well understood that variable frequency drives (VFDs) can cause overvoltage up to twice the DC bus voltage (2 pu, where 1 per unit is the DC bus voltage) at the machine winding terminals, especially if long power cables are used and/or fast rise and fall times are implemented. If the voltage oscillation is not fully decayed when the next pulse arrives, double pulsing occurs and the overvoltage can go up to 4 pu in one switching event. To prevent the damage of the 4 pu overvoltage to the electric machine insulation system, filters are commonly used between the VFD and the machine. The filters, however, add significant cost and size to the system. The higher dv/dt associated with the increasingly popular wide-bandgap devices requires even larger and more expensive filters to be installed. This paper proposes a new PWM control method, the double pulsing offset technique (DPOT), to restrain the overvoltage peak-to-peaks within 2 pu regardless of the switching frequency or dV/dt of the power semiconductor devices. The need to install filters, therefore, is potentially eliminated with the implementation of DPOT. This control scheme was validated using an accurate Reflected Wave phenomenon simulation model using finite element analysis (FEA). It was also fully implemented online and offline using a DSP and a SiC-MOSFET -based inverter. The experimental results with various operating conditions of the inverter are presented and analyzed. The results show that DPOT is successful in eliminating double pulsing even in harsh operating conditions such as high dV/dt, long cable length, and frequent polarity reversals.
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finite element analysis modeling and experimental verification of Reflected Wave phenomena in variable speed machine drive cables
International Electric Machines and Drives Conference, 2017Co-Authors: Han Xiong, Alex Louie, Rui Liu, Julia Zhang, Annette Von JouanneAbstract:Modern variable frequency drives (VFDs) are employed in various industry applications. The machine windings may be subject to large overvoltage, called Reflected Wave phenomena (RWP), if long cables are used or fast voltage rise times are implemented in the VFD system. The overvoltage places high electrical stress on the machine terminal windings, in the long term resulting in the winding insulation degradation and eventually a complete insulation breakdown. Several methods were proposed to model the RWP overvoltage based on the transmission line theory to study how various factors affect the RWP. The accurate acquisition of the electrical characteristics of the cable for the RWP models however proved to be difficult. This work proposes to use a 2D finite element analysis (FEA) model to simulate the electrical characteristics of the power cable under test. The characteristics are then used to construct a two-port network in a circuit simulation of RWP. The accuracy of the modeling technique is experimentally verified by measuring the voltage overshoots using cables of different lengths and under different switching frequencies and duty cycles. The simulation results are found to closely match the experimental findings after adopting a compensation method.
