Harmonics worsen the quality of electrical signals, hence, there is a need to eliminate them. The... more Harmonics worsen the quality of electrical signals, hence, there is a need to eliminate them. The test objects under discussion are single-phase versions of cascaded H-bridge (CHB) multilevel inverters (MLIs) whose switching angles are optimized to eliminate specific harmonics. The Dragonfly Algorithm (DA) is used to eradicate low-order harmonics, and its statistical performance is compared to that of many other optimization techniques, including Particle Swarm Optimization (PSO), Accelerated Particle Swarm Optimization (APSO), Differential Evolution (DE), and Grey Wolf Optimization (GWO). Various scenarios of the algorithms’ search agent population for inverters with seven, nine, and eleven levels of output voltages are comprehensively addressed in this research. No algorithm shows total dominance in every scenario. The DA is least impacted by the change in dimensions of the narrated problem.
his paper dwells on the need to integrate existing traditional sources of supply and the renewabl... more his paper dwells on the need to integrate existing traditional sources of supply and the renewable sources in order to establish a new energy system which is energy efficient, reliable, controllable, secure, compatible, economical and sustainable. Smart grid can overcome existing and future challenges in a cost effective manner. In this paper, the main focus is on the smart grid infrastructure, its capabilities, communication scenarios, technologies and energy management. The implementation of the vision of modernized intelligent smart grid can overcome problems and challenges of traditional electricity grids and utilities. The paper also focuses on the services and factors that attract the consumers and utilities to change the way they operate in order to improve the current services. Various measures are proposed to help in implementation and adoption of smart grid vision in Pakistan. Finally, paper presents smart grid research programs, deployments, issues and concerns.
This paper presents a computationally-intelligent adaptive weighted controller combination scheme... more This paper presents a computationally-intelligent adaptive weighted controller combination scheme to optimize the output-voltage regulation capability of a low power DC-DC buck converter. The proposed scheme beneficially combines two linear feedback controllers, namely, Proportional-IntegralDerivative (PID) controller and Linear-Quadratic-Regulator (LQR). The PID controller provides control effort based on the error-dynamics of output-voltage. Wherein, the term regarding the error-derivative is replaced with the information of capacitor-current to nullify the effects of noise injected by the derivative action during transients. The LQR provides optimal control decisions by utilizing the state-feedback of inductor-current and output-voltage. The outputs of PID controller and LQR are linearly combined by computing their weighted sum. The fixed weightages associated with each controller cannot compensate the parametric uncertainties and load-step transients. Therefore, the weightages a...
Aluminum winding transformers have not yet been introduced in the distribution network of Pakista... more Aluminum winding transformers have not yet been introduced in the distribution network of Pakistan. This paper evaluates the use of electrolytic aluminum in oil immersed distribution transformers and aluminum winding separately. The cost of aluminum winding transformer was compared with the conventional copper winding transformer for the same technical performance parameters. Feasibility of aluminum winding transformer in the distribution network is presented and its viability is established through analyzing a practical unit.
Wireless charging has become an emerging challenge to reduce the cost of a conventional plug-in c... more Wireless charging has become an emerging challenge to reduce the cost of a conventional plug-in charging system in electric vehicles especially for supercapacitors that are utilized for quick charging and low-energy demands. In this article, the design of an efficient wireless power transfer system has been presented using resonant inductive coupling technique for supercapacitor-based electric vehicle. Mathematical analysis, simulation, and experimental implementation of the proposed charging system have been carried out. Simulations of various parts of the systems are carried out in two different software, ANSYS MAXWELL and MATLAB. ANSYS MAXWELL has been used to calculate the various parameters for the transmitter and receiver coils such as self-inductance ( L), mutual inductance ( M), coupling coefficient ( K), and magnetic flux magnitude ( B). MATLAB has been utilized to calculate output power and efficiency of the proposed system using the mathematical relationships of these par...
The use of inefficient household appliances and their poor power quality results in energy wastag... more The use of inefficient household appliances and their poor power quality results in energy wastage in residential buildings. These appliances also force the power system to operate at low power factor which results in an ineffective energy utilization. This paper reports the energy consumption pattern of mostly used household appliances individually and collectively over a year. Their power quality parameters are measured through experimentation to calculate the reactive energy consumed by household appliances. This paper also proposes the reactive energy tariffs to enhance the awareness among domestic consumers to make efficient use of household appliances. Currently the reactive power management is being dealt for only the industrial consumer by imposing low power factor penalty. This research estimated that Lahore Electric Supply Company (LESCO) can generate a revenue of almost 150 million US dollars in one year from household consumers by applying three part tariff scheme on reactive energy. By improving the power factor it is estimated that an energy conservation of 1.1 Â 10 9 kWh per annum is also possible. Thus the proposed tariff for reactive energy encourages the domestic consumers to get involved actively in energy conservation while enabling the energy utilities to transfer more active energy to consumers without the expansion of the distribution network.
International Transactions on Electrical Energy Systems, 2019
This paper presents a robust and optimal output-voltage tracking controller for a DC-DC buck conv... more This paper presents a robust and optimal output-voltage tracking controller for a DC-DC buck converter. A fractional-order proportional-integral (FPI) controller is primarily used to eliminate the steady-state error and damp the oscil
This research paper presents a novel technique to determine the required value of capacitor used ... more This research paper presents a novel technique to determine the required value of capacitor used in a capacitor-run single phase induction motor. Dynamic analysis of main winding and auxiliary winding currents are performed and the electromagnetic flux revolving in the stator-rotor air gap is studied. In capacitor-run single phase induction motors, the most suitable capacitor is one that produces an electromagnetic flux that has a uniform trajectory (distribution) along the air gap. The novel technique presented in this research paper is the application of roundness algorithm to determine the most uniform trajectory of electromagnetic flux produced by varying auxiliary winding capacitors. The value of capacitance thus found from the proposed technique is compared with the motor manufacturer recommended capacitance. The agreement of the comparison validates the usefulness of the proposed technique.
Analog Integrated Circuits and Signal Processing, 2019
This letter discusses an optocoupler based variable resistor circuit. The circuit has digital inp... more This letter discusses an optocoupler based variable resistor circuit. The circuit has digital inputs and the output is a variable resistance with a resolution (unit step size) of 1 X. The circuit is easy to assemble especially for microsystems and low cost. Attractive features include variable resistance range scalability, galvanic isolation and digital logic based input.
For maximum power point (MPP) application, the transient evolution of capacitor can be exploited ... more For maximum power point (MPP) application, the transient evolution of capacitor can be exploited to examine the power-voltage (P-V) characteristics of a photovoltaic (PV) array. This method is simple and inexpensive. In addition, it can be implemented on any array size whether un-shaded or partially shaded. This paper presents a new MPPT technique that scans the P-V curve of PV array with a series capacitor (C scan) through a unique H-bridge architecture. The proposed technique employs a simple algorithm, which controls the H-bridge to scan the P-V curve in two sequences: (1) during charging of capacitor, and (2) during discharging of capacitor. The proposed MPPT neither requires the isolation of PV array from load nor executes power loss during checking of P-V curve. The effects of input capacitor (C in) of converter during scanning of P-V curve are comprehensively discussed, and then the correct sizing of C scan according to array size is explained with a design example. A comparative analysis of different MPPTs in the context of tracking ability, dynamic, and steady state efficiencies is presented. This analysis highlights the advantage of proposed technique over other MPPTs. Finally, the fundamental operation of proposed MPPT is verified through experimental results.
This paper presents the effects of partial shading on PV arrays. The characteristics of PV array ... more This paper presents the effects of partial shading on PV arrays. The characteristics of PV array under various shading patterns are modeled in the form of current-voltage graphs. The analysis of these graphs leads to several critical observations, which are summarized in five statements. Based on these statements, two hypotheses are presented: 1) irrespective of any partial shading pattern, maximum number of local maxima in a PV array is equal to the number of series connected modules in a string, 2) number of local maxima in a PV array is equal to the quantity of open circuit voltage values (excluding last value) around which bypass diodes of the shaded modules become forward biased plus 1. Finally, both hypotheses are verified with the help of simulation results. Other than that, our findings provide exact information about the shaded PV module in an entire PV system. This study strengthens not only the theoretical knowledge of shading phenomena but also helps exploring the partial shading effects on PV array without any aid of software, advanced techniques or practical systems. • Since these models are based on complex intelligent schemes [24-26], therefore, for user convenience, most of these research articles provide the working principle of the models in the form of flowcharts. Nevertheless, the user needs to understand the flowchart and other basic parameters of complex techniques to run these models. • These models can be implemented in C/Matlab software [27,28]. Therefore, basic knowledge of these software is mandatory for the user. Moreover, a computer platform is required. Even when the user implements all these steps, the conceptual understanding of PS effects on PV array is limited. It is because of the reason that the user will get the I-V curve of PV array, which indeed gives the information of number of LMs present on the I-V curve, but doesn't indicate that which strings or modules in a PV array are responsible for these LMs. On the other hand, some researchers explore PS effects using practical PV systems [29-31]. Hence, a simple and comprehensive analysis regarding the PS effects on PV array is limited in literature.
In this article, a new maximum power point tracking (MPPT) method is proposed. The proposed MPPT ... more In this article, a new maximum power point tracking (MPPT) method is proposed. The proposed MPPT is in principle, a hybrid version of open circuit voltage (V oc), short-circuit current (I sc) and perturb & observe (P&O) techniques. Improved relations are derived in this paper on the basis of which the proposed MPPT operates. These are: voltage and current relations of PV which correspond to MPP, duty cycle function of converter to set PV operating point at MPP, criterion to measure the varying weather conditions and limits criteria to evaluate the steady weather conditions. All these relations are incorporated in the control architecture of the proposed technique, which contains three loops: E-MPP loop, R-MPP loop and Sloop. The proposed MPPT and past-proposed methods are tested through computer aided simulations and experimental prototype under dynamic and steady weather conditions. The comparative analysis between the MPPTs indicates that the proposed technique outperforms other MPPTs by a significant margin.
2015 International Conference on Open Source Systems & Technologies (ICOSST), 2015
This paper investigates the effect of two HVDC grid segmentation topologies i.e. hybrid HVAC-HVDC... more This paper investigates the effect of two HVDC grid segmentation topologies i.e. hybrid HVAC-HVDC and standalone HVDC on the transient stability of a 15-bus electric grid. For this purpose, four HVDC station configurations and three HVDC technologies are considered. A three phase AC fault is applied at one of the buses and the rotor angle of one of the generators is analyzed. The results show that transient stability is least affected when standalone HVDC topology is used for grid segmentation.
2009 International Conference on Electrical Machines and Systems, 2009
This paper addresses shaft end-to-end and shaft-to-frame voltages that appear in a 400-V 15-kW in... more This paper addresses shaft end-to-end and shaft-to-frame voltages that appear in a 400-V 15-kW induction motor driven by a voltage-source PWM inverter. Although both shaft voltages have been known to be associated to common-mode voltages, this paper demonstrates a shaft end-to-end voltage in the absence of common-mode voltages. Extensive experiments are performed with the motor subjected to differential-mode voltages. Results show that differential-mode voltages applied across motor phases also cause a shaft end-to-end voltage. It is concluded that the combination of differential-mode voltages with high dv/dt and high-frequency motor asymmetry causes a shaft end-to-end voltage. A model of one motor phase is presented to explain the generation of the shaft end-to-end voltage.
This paper addresses shaft end-to-end and shaft-toframe voltages that appear in the 400-V 15-kW i... more This paper addresses shaft end-to-end and shaft-toframe voltages that appear in the 400-V 15-kW induction motor driven by a voltage-source pulsewidth modulation inverter. It has been known that an inverter-fed common-mode voltage causes both shaft voltages. Extensive experiments are performed with an ungrounded motor subjected to a differential-mode voltage. Experimental results show that the differential-mode voltage applied across three-phase, two-phase, or single-phase stator windings also causes a shaft end-to-end voltage. It is concluded that the combination of a steep change in differential-mode voltage and highfrequency motor asymmetry causes a shaft end-to-end voltage. A motor model is presented to explain the generation of shaft end-toend voltage.
This paper addresses shaft end-to-end and shaft-toframe voltages that appear in the 400-V, 15-kW ... more This paper addresses shaft end-to-end and shaft-toframe voltages that appear in the 400-V, 15-kW induction motor driven by a voltage-source pulsewidth modulation (PWM) inverter. A shaft-to-frame voltage can be observed at either shaft end with respect to the grounded motor frame. A shaft end-to-end voltage can be observed as a voltage difference between the shaft-to-frame voltage at the drive end (DE) and that at the nondrive end (NDE). Experimental waveforms lead to the following interesting observations: motor internal coupling and parasitic capacitance, along with the high-frequency common-mode voltage generated by the PWM inverter, cause a shaft-to-frame voltage with a peak of 8 V at both DE and NDE. When the shaft-to-frame voltage at either DE or NDE exceeds a dielectric breakdown voltage of thin bearing lubricating grease films, a shaft end-to-end voltage with a peak of 2 V and a width of 30 ns occurs along the motor shaft. This paper makes experimental discussions on the shaft end-to-end voltage generation. Installing a differential-mode filter and/or a common-mode filter on the motor drive system gives a hint on the mechanisms of the occurrence of the shaft end-to-end voltage.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Harmonics worsen the quality of electrical signals, hence, there is a need to eliminate them. The... more Harmonics worsen the quality of electrical signals, hence, there is a need to eliminate them. The test objects under discussion are single-phase versions of cascaded H-bridge (CHB) multilevel inverters (MLIs) whose switching angles are optimized to eliminate specific harmonics. The Dragonfly Algorithm (DA) is used to eradicate low-order harmonics, and its statistical performance is compared to that of many other optimization techniques, including Particle Swarm Optimization (PSO), Accelerated Particle Swarm Optimization (APSO), Differential Evolution (DE), and Grey Wolf Optimization (GWO). Various scenarios of the algorithms’ search agent population for inverters with seven, nine, and eleven levels of output voltages are comprehensively addressed in this research. No algorithm shows total dominance in every scenario. The DA is least impacted by the change in dimensions of the narrated problem.
his paper dwells on the need to integrate existing traditional sources of supply and the renewabl... more his paper dwells on the need to integrate existing traditional sources of supply and the renewable sources in order to establish a new energy system which is energy efficient, reliable, controllable, secure, compatible, economical and sustainable. Smart grid can overcome existing and future challenges in a cost effective manner. In this paper, the main focus is on the smart grid infrastructure, its capabilities, communication scenarios, technologies and energy management. The implementation of the vision of modernized intelligent smart grid can overcome problems and challenges of traditional electricity grids and utilities. The paper also focuses on the services and factors that attract the consumers and utilities to change the way they operate in order to improve the current services. Various measures are proposed to help in implementation and adoption of smart grid vision in Pakistan. Finally, paper presents smart grid research programs, deployments, issues and concerns.
This paper presents a computationally-intelligent adaptive weighted controller combination scheme... more This paper presents a computationally-intelligent adaptive weighted controller combination scheme to optimize the output-voltage regulation capability of a low power DC-DC buck converter. The proposed scheme beneficially combines two linear feedback controllers, namely, Proportional-IntegralDerivative (PID) controller and Linear-Quadratic-Regulator (LQR). The PID controller provides control effort based on the error-dynamics of output-voltage. Wherein, the term regarding the error-derivative is replaced with the information of capacitor-current to nullify the effects of noise injected by the derivative action during transients. The LQR provides optimal control decisions by utilizing the state-feedback of inductor-current and output-voltage. The outputs of PID controller and LQR are linearly combined by computing their weighted sum. The fixed weightages associated with each controller cannot compensate the parametric uncertainties and load-step transients. Therefore, the weightages a...
Aluminum winding transformers have not yet been introduced in the distribution network of Pakista... more Aluminum winding transformers have not yet been introduced in the distribution network of Pakistan. This paper evaluates the use of electrolytic aluminum in oil immersed distribution transformers and aluminum winding separately. The cost of aluminum winding transformer was compared with the conventional copper winding transformer for the same technical performance parameters. Feasibility of aluminum winding transformer in the distribution network is presented and its viability is established through analyzing a practical unit.
Wireless charging has become an emerging challenge to reduce the cost of a conventional plug-in c... more Wireless charging has become an emerging challenge to reduce the cost of a conventional plug-in charging system in electric vehicles especially for supercapacitors that are utilized for quick charging and low-energy demands. In this article, the design of an efficient wireless power transfer system has been presented using resonant inductive coupling technique for supercapacitor-based electric vehicle. Mathematical analysis, simulation, and experimental implementation of the proposed charging system have been carried out. Simulations of various parts of the systems are carried out in two different software, ANSYS MAXWELL and MATLAB. ANSYS MAXWELL has been used to calculate the various parameters for the transmitter and receiver coils such as self-inductance ( L), mutual inductance ( M), coupling coefficient ( K), and magnetic flux magnitude ( B). MATLAB has been utilized to calculate output power and efficiency of the proposed system using the mathematical relationships of these par...
The use of inefficient household appliances and their poor power quality results in energy wastag... more The use of inefficient household appliances and their poor power quality results in energy wastage in residential buildings. These appliances also force the power system to operate at low power factor which results in an ineffective energy utilization. This paper reports the energy consumption pattern of mostly used household appliances individually and collectively over a year. Their power quality parameters are measured through experimentation to calculate the reactive energy consumed by household appliances. This paper also proposes the reactive energy tariffs to enhance the awareness among domestic consumers to make efficient use of household appliances. Currently the reactive power management is being dealt for only the industrial consumer by imposing low power factor penalty. This research estimated that Lahore Electric Supply Company (LESCO) can generate a revenue of almost 150 million US dollars in one year from household consumers by applying three part tariff scheme on reactive energy. By improving the power factor it is estimated that an energy conservation of 1.1 Â 10 9 kWh per annum is also possible. Thus the proposed tariff for reactive energy encourages the domestic consumers to get involved actively in energy conservation while enabling the energy utilities to transfer more active energy to consumers without the expansion of the distribution network.
International Transactions on Electrical Energy Systems, 2019
This paper presents a robust and optimal output-voltage tracking controller for a DC-DC buck conv... more This paper presents a robust and optimal output-voltage tracking controller for a DC-DC buck converter. A fractional-order proportional-integral (FPI) controller is primarily used to eliminate the steady-state error and damp the oscil
This research paper presents a novel technique to determine the required value of capacitor used ... more This research paper presents a novel technique to determine the required value of capacitor used in a capacitor-run single phase induction motor. Dynamic analysis of main winding and auxiliary winding currents are performed and the electromagnetic flux revolving in the stator-rotor air gap is studied. In capacitor-run single phase induction motors, the most suitable capacitor is one that produces an electromagnetic flux that has a uniform trajectory (distribution) along the air gap. The novel technique presented in this research paper is the application of roundness algorithm to determine the most uniform trajectory of electromagnetic flux produced by varying auxiliary winding capacitors. The value of capacitance thus found from the proposed technique is compared with the motor manufacturer recommended capacitance. The agreement of the comparison validates the usefulness of the proposed technique.
Analog Integrated Circuits and Signal Processing, 2019
This letter discusses an optocoupler based variable resistor circuit. The circuit has digital inp... more This letter discusses an optocoupler based variable resistor circuit. The circuit has digital inputs and the output is a variable resistance with a resolution (unit step size) of 1 X. The circuit is easy to assemble especially for microsystems and low cost. Attractive features include variable resistance range scalability, galvanic isolation and digital logic based input.
For maximum power point (MPP) application, the transient evolution of capacitor can be exploited ... more For maximum power point (MPP) application, the transient evolution of capacitor can be exploited to examine the power-voltage (P-V) characteristics of a photovoltaic (PV) array. This method is simple and inexpensive. In addition, it can be implemented on any array size whether un-shaded or partially shaded. This paper presents a new MPPT technique that scans the P-V curve of PV array with a series capacitor (C scan) through a unique H-bridge architecture. The proposed technique employs a simple algorithm, which controls the H-bridge to scan the P-V curve in two sequences: (1) during charging of capacitor, and (2) during discharging of capacitor. The proposed MPPT neither requires the isolation of PV array from load nor executes power loss during checking of P-V curve. The effects of input capacitor (C in) of converter during scanning of P-V curve are comprehensively discussed, and then the correct sizing of C scan according to array size is explained with a design example. A comparative analysis of different MPPTs in the context of tracking ability, dynamic, and steady state efficiencies is presented. This analysis highlights the advantage of proposed technique over other MPPTs. Finally, the fundamental operation of proposed MPPT is verified through experimental results.
This paper presents the effects of partial shading on PV arrays. The characteristics of PV array ... more This paper presents the effects of partial shading on PV arrays. The characteristics of PV array under various shading patterns are modeled in the form of current-voltage graphs. The analysis of these graphs leads to several critical observations, which are summarized in five statements. Based on these statements, two hypotheses are presented: 1) irrespective of any partial shading pattern, maximum number of local maxima in a PV array is equal to the number of series connected modules in a string, 2) number of local maxima in a PV array is equal to the quantity of open circuit voltage values (excluding last value) around which bypass diodes of the shaded modules become forward biased plus 1. Finally, both hypotheses are verified with the help of simulation results. Other than that, our findings provide exact information about the shaded PV module in an entire PV system. This study strengthens not only the theoretical knowledge of shading phenomena but also helps exploring the partial shading effects on PV array without any aid of software, advanced techniques or practical systems. • Since these models are based on complex intelligent schemes [24-26], therefore, for user convenience, most of these research articles provide the working principle of the models in the form of flowcharts. Nevertheless, the user needs to understand the flowchart and other basic parameters of complex techniques to run these models. • These models can be implemented in C/Matlab software [27,28]. Therefore, basic knowledge of these software is mandatory for the user. Moreover, a computer platform is required. Even when the user implements all these steps, the conceptual understanding of PS effects on PV array is limited. It is because of the reason that the user will get the I-V curve of PV array, which indeed gives the information of number of LMs present on the I-V curve, but doesn't indicate that which strings or modules in a PV array are responsible for these LMs. On the other hand, some researchers explore PS effects using practical PV systems [29-31]. Hence, a simple and comprehensive analysis regarding the PS effects on PV array is limited in literature.
In this article, a new maximum power point tracking (MPPT) method is proposed. The proposed MPPT ... more In this article, a new maximum power point tracking (MPPT) method is proposed. The proposed MPPT is in principle, a hybrid version of open circuit voltage (V oc), short-circuit current (I sc) and perturb & observe (P&O) techniques. Improved relations are derived in this paper on the basis of which the proposed MPPT operates. These are: voltage and current relations of PV which correspond to MPP, duty cycle function of converter to set PV operating point at MPP, criterion to measure the varying weather conditions and limits criteria to evaluate the steady weather conditions. All these relations are incorporated in the control architecture of the proposed technique, which contains three loops: E-MPP loop, R-MPP loop and Sloop. The proposed MPPT and past-proposed methods are tested through computer aided simulations and experimental prototype under dynamic and steady weather conditions. The comparative analysis between the MPPTs indicates that the proposed technique outperforms other MPPTs by a significant margin.
2015 International Conference on Open Source Systems & Technologies (ICOSST), 2015
This paper investigates the effect of two HVDC grid segmentation topologies i.e. hybrid HVAC-HVDC... more This paper investigates the effect of two HVDC grid segmentation topologies i.e. hybrid HVAC-HVDC and standalone HVDC on the transient stability of a 15-bus electric grid. For this purpose, four HVDC station configurations and three HVDC technologies are considered. A three phase AC fault is applied at one of the buses and the rotor angle of one of the generators is analyzed. The results show that transient stability is least affected when standalone HVDC topology is used for grid segmentation.
2009 International Conference on Electrical Machines and Systems, 2009
This paper addresses shaft end-to-end and shaft-to-frame voltages that appear in a 400-V 15-kW in... more This paper addresses shaft end-to-end and shaft-to-frame voltages that appear in a 400-V 15-kW induction motor driven by a voltage-source PWM inverter. Although both shaft voltages have been known to be associated to common-mode voltages, this paper demonstrates a shaft end-to-end voltage in the absence of common-mode voltages. Extensive experiments are performed with the motor subjected to differential-mode voltages. Results show that differential-mode voltages applied across motor phases also cause a shaft end-to-end voltage. It is concluded that the combination of differential-mode voltages with high dv/dt and high-frequency motor asymmetry causes a shaft end-to-end voltage. A model of one motor phase is presented to explain the generation of the shaft end-to-end voltage.
This paper addresses shaft end-to-end and shaft-toframe voltages that appear in the 400-V 15-kW i... more This paper addresses shaft end-to-end and shaft-toframe voltages that appear in the 400-V 15-kW induction motor driven by a voltage-source pulsewidth modulation inverter. It has been known that an inverter-fed common-mode voltage causes both shaft voltages. Extensive experiments are performed with an ungrounded motor subjected to a differential-mode voltage. Experimental results show that the differential-mode voltage applied across three-phase, two-phase, or single-phase stator windings also causes a shaft end-to-end voltage. It is concluded that the combination of a steep change in differential-mode voltage and highfrequency motor asymmetry causes a shaft end-to-end voltage. A motor model is presented to explain the generation of shaft end-toend voltage.
This paper addresses shaft end-to-end and shaft-toframe voltages that appear in the 400-V, 15-kW ... more This paper addresses shaft end-to-end and shaft-toframe voltages that appear in the 400-V, 15-kW induction motor driven by a voltage-source pulsewidth modulation (PWM) inverter. A shaft-to-frame voltage can be observed at either shaft end with respect to the grounded motor frame. A shaft end-to-end voltage can be observed as a voltage difference between the shaft-to-frame voltage at the drive end (DE) and that at the nondrive end (NDE). Experimental waveforms lead to the following interesting observations: motor internal coupling and parasitic capacitance, along with the high-frequency common-mode voltage generated by the PWM inverter, cause a shaft-to-frame voltage with a peak of 8 V at both DE and NDE. When the shaft-to-frame voltage at either DE or NDE exceeds a dielectric breakdown voltage of thin bearing lubricating grease films, a shaft end-to-end voltage with a peak of 2 V and a width of 30 ns occurs along the motor shaft. This paper makes experimental discussions on the shaft end-to-end voltage generation. Installing a differential-mode filter and/or a common-mode filter on the motor drive system gives a hint on the mechanisms of the occurrence of the shaft end-to-end voltage.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
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