2020 IEEE International Conference on Industrial Technology (ICIT)
This paper presents a parameter estimation method for a permanent magnet synchronous machine (PMS... more This paper presents a parameter estimation method for a permanent magnet synchronous machine (PMSM) based on the instantaneous input impedance, which is defined as a function of the instantaneous voltage and current space vectors fixed to the rotor reference frame. The parameters are calculated solving the nonlinear optimization problem to minimize the difference between the estimated and measured input voltages. This problem was solved using Interior-Points, and Genetic Algorithm (GA) to compare the computing time required in each case. The parameter estimation method was evaluated using data obtained from a co-simulation between ANSYS RMxprt-Simplorer® and MATLAB-SIMULINK® in a PMSM drive application using conventional Field Oriented Control (FOC) approach. The results prove the method capability to estimate the direct and quadrature self-inductances, and the magnet flux. Also, the stator a reasonable value of the stator resistance can be estimated. Finally, the paper presents an additional simulation of the PMSM using the estimated parameters, and the outcomes have a good correspondence with those obtained from the co-simulation.
The paper presents the implementation of a nonlinear Automatic Voltage Regulator (AVR) for a sync... more The paper presents the implementation of a nonlinear Automatic Voltage Regulator (AVR) for a synchronous generator supplying a passive load. The AVR is designed using the feedback exact linearization of the synchronous machine dynamic equations fixed to the rotor reference frame and setting a Linear Quadratic Regulator (LQR) controller to adjust the machine field voltage. This algorithm was first evaluated using an OPAL-RT real-time simulator environment and then, an actual synchronous machine was included in the system using a Hardware in the Loop (HIL) approach. The system was implemented and experimentally verified on a 1.2 kVA cylindrical-rotor synchronous generator, where the proposed AVR regulates the terminal voltage with a steady-state error below of 1% for load steps of 40%.
2021 IEEE Workshop on Electrical Machines Design, Control and Diagnosis (WEMDCD), 2021
This paper presents an efficiency estimation method for inverter-fed induction motors using a rot... more This paper presents an efficiency estimation method for inverter-fed induction motors using a rotor currents observer. A recursive linear combination of stator currents and previous rotor currents' values are used to calculate the currents. The deep-bar model machine parameters are estimated from a no-load motor start-up transient instantaneous impedance. During the efficiency estimation process, the algorithm requires the stator current measurement and the machine parameters. The proposed methodology was experimentally validated using an induction motor with a load ranged between 30% to 105%. The results are compared with the IEC600-34-2-2013-TS, with a deviation of 0.5% for the worst case. This performance demonstrates the application of the methodology in in-situ applications.
2018 IEEE Third Ecuador Technical Chapters Meeting (ETCM), 2018
This paper presents an evaluation of the effects of variable frequency drives (VFDs) on induction... more This paper presents an evaluation of the effects of variable frequency drives (VFDs) on induction machines efficiency. For this purpose, an experimental evaluation using international standards IEEE 112, IEC 60034-2-1 and IEC 60034-2-3 (draft version), was set up. These standards estimated the induction machine’s efficiency based on a loss segregation approach to consider the stator, core, friction, rotor, stray-load, and additional losses contribution. Additionally, the machine’s losses were studied using a time-stepping, 2D, Finite Element Method (FEM) analysis on the open-source software Gmsh–GetDP. This analysis used voltage waveforms suggested by IEC 60034-2-3 and a motor design with the same rated characteristics to those used in the experimental stage.
2017 IEEE Workshop on Power Electronics and Power Quality Applications (PEPQA), 2017
This paper presents an experimental evaluation of the voltage unbalances effects in the efficienc... more This paper presents an experimental evaluation of the voltage unbalances effects in the efficiency of induction motors. In that sense, two distinct National Electrical Manufacturers Associations (NEMA) design were evaluated to seek the changes on their performance. The voltage unbalance was assessed using the Complex Voltage Unbalance Factor (CVUF). The experimental methodology consisted in a segregation losses approach to study the stator, core, friction, rotor, and stray-load losses clearly. First, a no-load test was carried out in both motors keeping constant the magnitude and the angle of CVUF. Next, a load test was accomplished ranging the mechanical load from 120% down to 30% of the nominal load using the same CVUF of the no-load test. Finally, according to the results of NEMA design B motor has the greatest losses increment because it was the most affected by the skin effect.
2018 XIII International Conference on Electrical Machines (ICEM), 2018
This work compares variable speed controllers applied to single phase unbalanced induction motors... more This work compares variable speed controllers applied to single phase unbalanced induction motors. The single phase machine feeds from three phase inverters or double H bridges with scalar and vector control. For comparing the machine's performance the controller uses first a classical table based DTC and predictive based DTC for the vector controller, and later a standard V /f for the scalar controller. The simulations use a voltage behind reactance model of the single phase machine implemented in Simulink®, and experimental tests confirm the validity of the simulations. Also, the results show the feasibility of using different controllers, vector or scalar, to obtain low start-up currents, speed regulation and high electric torque, when compared with a direct start-up using capacitors in the auxiliary winding.
2018 IEEE Third Ecuador Technical Chapters Meeting (ETCM), 2018
This paper presents the study of the effect of increasing the penetration of Doubly Fed Induction... more This paper presents the study of the effect of increasing the penetration of Doubly Fed Induction Generators (DFIG) in the transient stability performance of a power system using a detailed model of the DFIG including the back to back converter that uses Direct Torque Control (DTC) and Direct Power Control (DPC) on the machine- and grid-side inverters respectively. The wind turbine model includes the relation between the power coefficient, the tip speed ratio, and the pitch angle, and a Maximum Power Point Tracking (MPPT) strategy to define the torque reference. The stability analysis evaluated the critical clearance time (CCT) of three-phase faults in the 9-bus IEEE power system considering different levels of wind power penetration. Additionally, a wind turbine with a squirrel cage induction generator (SQIG), and synchronous generator cases were simulated as comparison patterns. Furthermore, to evaluate the power system transient performance with high penetration of DFIG generation, the Transient Stability Index (TSI) and the Transient Rotor Angle Severity Index (TRASI) were calculated and compared.
2016 IEEE Applied Power Electronics Conference and Exposition (APEC), 2016
This paper presents an enhanced strategy for Direct Torque Control (DTC) combining artificial int... more This paper presents an enhanced strategy for Direct Torque Control (DTC) combining artificial intelligent (AI) and predictive algorithms. The advantages of both methodologies are merged to solve the main problems of closed loop controlled induction machines (IM) and, in particular the drawbacks of the classical DTC. Predictive DTC (P-DTC) methods solve the problems of the high torque ripple and poor performance at both starting condition and low mechanical speed operation. However these strategies depend on the IM parameter's knowledge. A new approach of fuzzy logic control (FLC) with dynamic rules based on the laws of predictive DTC is proposed to reduce the parameter dependency and improve the performance of the P-DPC. The predictive rule's main idea is to compute the angle difference in between the lines of constant torque and constant stator flux magnitude expressed as a function of the (αβ) inverter voltage components. For verification purposes, simulations of the DTC, P-DTC and proposed Fuzzy Predictive DTC (FP-DTC) were conducted and compared. Experimental results for the three controllers confirm the expected performance of the proposed algorithm.
This paper presents a methodology for mid-term load forecasting using Artificial Neural Networks ... more This paper presents a methodology for mid-term load forecasting using Artificial Neural Networks (ANN). The inputs to ANN are real time data available from Supervisory Control and Data Acquisition and Distribution Management Systems (SCADA/DMS) databases. Due to a number of reasons, historical data stored in SCADA/DMS databases is affected by distorted measurements that can jeopardize the load forecasting results. This paper explores mid-term load demand forecasting using ANN considering distorted measurements in SCADA/DMS database. Proposed technique was applied to real-world measurements acquired from a 8.3 kV substation in Venezuela. ANN's forecasted results are compared with an exponential smoothing load forecasting procedure.
2015 IEEE Workshop on Power Electronics and Power Quality Applications (PEPQA), 2015
—This work presents a comparison of three techniques for parameter estimation of the induction ma... more —This work presents a comparison of three techniques for parameter estimation of the induction machine dynamic model. The first estimation method is based on measurements with the rotor at standstill while several single phase voltage sources are applied at different frequencies. The second method is based on obtaining the instantaneous measurements of voltages and currents during a direct start-up in no load or load condition. To validate the results obtained in each one of these tests, conventional estimation methods are applied to a wound rotor induction machine, according to international standards. The estimation methods are verified using simulations. The obtained results will allow to analyze the accuracy of both methods, and their applicability in industrial environments. The analysis shows the practical conditions where each one of these methods can be applied successfully.
2018 IEEE Third Ecuador Technical Chapters Meeting (ETCM), 2018
This paper presents an evaluation of the effects of variable frequency drives (VFDs) on induction... more This paper presents an evaluation of the effects of variable frequency drives (VFDs) on induction machines efficiency. For this purpose, an experimental evaluation using international standards IEEE 112, IEC 60034-2-1 and IEC 60034-2-3 (draft version), was set up. These standards estimated the induction machine's efficiency based on a loss segregation approach to consider the stator, core, friction, rotor, stray-load, and additional losses contribution. Additionally, the machine's losses were studied using a time-stepping, 2D, Finite Element Method (FEM) analysis on the open-source software Gmsh-GetDP. This analysis used voltage waveforms suggested by IEC 60034-2-3 and a motor design with the same rated characteristics to those used in the experimental stage.
2020 IEEE International Conference on Industrial Technology (ICIT)
This paper presents a parameter estimation method for a permanent magnet synchronous machine (PMS... more This paper presents a parameter estimation method for a permanent magnet synchronous machine (PMSM) based on the instantaneous input impedance, which is defined as a function of the instantaneous voltage and current space vectors fixed to the rotor reference frame. The parameters are calculated solving the nonlinear optimization problem to minimize the difference between the estimated and measured input voltages. This problem was solved using Interior-Points, and Genetic Algorithm (GA) to compare the computing time required in each case. The parameter estimation method was evaluated using data obtained from a co-simulation between ANSYS RMxprt-Simplorer® and MATLAB-SIMULINK® in a PMSM drive application using conventional Field Oriented Control (FOC) approach. The results prove the method capability to estimate the direct and quadrature self-inductances, and the magnet flux. Also, the stator a reasonable value of the stator resistance can be estimated. Finally, the paper presents an additional simulation of the PMSM using the estimated parameters, and the outcomes have a good correspondence with those obtained from the co-simulation.
The paper presents the implementation of a nonlinear Automatic Voltage Regulator (AVR) for a sync... more The paper presents the implementation of a nonlinear Automatic Voltage Regulator (AVR) for a synchronous generator supplying a passive load. The AVR is designed using the feedback exact linearization of the synchronous machine dynamic equations fixed to the rotor reference frame and setting a Linear Quadratic Regulator (LQR) controller to adjust the machine field voltage. This algorithm was first evaluated using an OPAL-RT real-time simulator environment and then, an actual synchronous machine was included in the system using a Hardware in the Loop (HIL) approach. The system was implemented and experimentally verified on a 1.2 kVA cylindrical-rotor synchronous generator, where the proposed AVR regulates the terminal voltage with a steady-state error below of 1% for load steps of 40%.
2021 IEEE Workshop on Electrical Machines Design, Control and Diagnosis (WEMDCD), 2021
This paper presents an efficiency estimation method for inverter-fed induction motors using a rot... more This paper presents an efficiency estimation method for inverter-fed induction motors using a rotor currents observer. A recursive linear combination of stator currents and previous rotor currents' values are used to calculate the currents. The deep-bar model machine parameters are estimated from a no-load motor start-up transient instantaneous impedance. During the efficiency estimation process, the algorithm requires the stator current measurement and the machine parameters. The proposed methodology was experimentally validated using an induction motor with a load ranged between 30% to 105%. The results are compared with the IEC600-34-2-2013-TS, with a deviation of 0.5% for the worst case. This performance demonstrates the application of the methodology in in-situ applications.
2018 IEEE Third Ecuador Technical Chapters Meeting (ETCM), 2018
This paper presents an evaluation of the effects of variable frequency drives (VFDs) on induction... more This paper presents an evaluation of the effects of variable frequency drives (VFDs) on induction machines efficiency. For this purpose, an experimental evaluation using international standards IEEE 112, IEC 60034-2-1 and IEC 60034-2-3 (draft version), was set up. These standards estimated the induction machine’s efficiency based on a loss segregation approach to consider the stator, core, friction, rotor, stray-load, and additional losses contribution. Additionally, the machine’s losses were studied using a time-stepping, 2D, Finite Element Method (FEM) analysis on the open-source software Gmsh–GetDP. This analysis used voltage waveforms suggested by IEC 60034-2-3 and a motor design with the same rated characteristics to those used in the experimental stage.
2017 IEEE Workshop on Power Electronics and Power Quality Applications (PEPQA), 2017
This paper presents an experimental evaluation of the voltage unbalances effects in the efficienc... more This paper presents an experimental evaluation of the voltage unbalances effects in the efficiency of induction motors. In that sense, two distinct National Electrical Manufacturers Associations (NEMA) design were evaluated to seek the changes on their performance. The voltage unbalance was assessed using the Complex Voltage Unbalance Factor (CVUF). The experimental methodology consisted in a segregation losses approach to study the stator, core, friction, rotor, and stray-load losses clearly. First, a no-load test was carried out in both motors keeping constant the magnitude and the angle of CVUF. Next, a load test was accomplished ranging the mechanical load from 120% down to 30% of the nominal load using the same CVUF of the no-load test. Finally, according to the results of NEMA design B motor has the greatest losses increment because it was the most affected by the skin effect.
2018 XIII International Conference on Electrical Machines (ICEM), 2018
This work compares variable speed controllers applied to single phase unbalanced induction motors... more This work compares variable speed controllers applied to single phase unbalanced induction motors. The single phase machine feeds from three phase inverters or double H bridges with scalar and vector control. For comparing the machine's performance the controller uses first a classical table based DTC and predictive based DTC for the vector controller, and later a standard V /f for the scalar controller. The simulations use a voltage behind reactance model of the single phase machine implemented in Simulink®, and experimental tests confirm the validity of the simulations. Also, the results show the feasibility of using different controllers, vector or scalar, to obtain low start-up currents, speed regulation and high electric torque, when compared with a direct start-up using capacitors in the auxiliary winding.
2018 IEEE Third Ecuador Technical Chapters Meeting (ETCM), 2018
This paper presents the study of the effect of increasing the penetration of Doubly Fed Induction... more This paper presents the study of the effect of increasing the penetration of Doubly Fed Induction Generators (DFIG) in the transient stability performance of a power system using a detailed model of the DFIG including the back to back converter that uses Direct Torque Control (DTC) and Direct Power Control (DPC) on the machine- and grid-side inverters respectively. The wind turbine model includes the relation between the power coefficient, the tip speed ratio, and the pitch angle, and a Maximum Power Point Tracking (MPPT) strategy to define the torque reference. The stability analysis evaluated the critical clearance time (CCT) of three-phase faults in the 9-bus IEEE power system considering different levels of wind power penetration. Additionally, a wind turbine with a squirrel cage induction generator (SQIG), and synchronous generator cases were simulated as comparison patterns. Furthermore, to evaluate the power system transient performance with high penetration of DFIG generation, the Transient Stability Index (TSI) and the Transient Rotor Angle Severity Index (TRASI) were calculated and compared.
2016 IEEE Applied Power Electronics Conference and Exposition (APEC), 2016
This paper presents an enhanced strategy for Direct Torque Control (DTC) combining artificial int... more This paper presents an enhanced strategy for Direct Torque Control (DTC) combining artificial intelligent (AI) and predictive algorithms. The advantages of both methodologies are merged to solve the main problems of closed loop controlled induction machines (IM) and, in particular the drawbacks of the classical DTC. Predictive DTC (P-DTC) methods solve the problems of the high torque ripple and poor performance at both starting condition and low mechanical speed operation. However these strategies depend on the IM parameter's knowledge. A new approach of fuzzy logic control (FLC) with dynamic rules based on the laws of predictive DTC is proposed to reduce the parameter dependency and improve the performance of the P-DPC. The predictive rule's main idea is to compute the angle difference in between the lines of constant torque and constant stator flux magnitude expressed as a function of the (αβ) inverter voltage components. For verification purposes, simulations of the DTC, P-DTC and proposed Fuzzy Predictive DTC (FP-DTC) were conducted and compared. Experimental results for the three controllers confirm the expected performance of the proposed algorithm.
This paper presents a methodology for mid-term load forecasting using Artificial Neural Networks ... more This paper presents a methodology for mid-term load forecasting using Artificial Neural Networks (ANN). The inputs to ANN are real time data available from Supervisory Control and Data Acquisition and Distribution Management Systems (SCADA/DMS) databases. Due to a number of reasons, historical data stored in SCADA/DMS databases is affected by distorted measurements that can jeopardize the load forecasting results. This paper explores mid-term load demand forecasting using ANN considering distorted measurements in SCADA/DMS database. Proposed technique was applied to real-world measurements acquired from a 8.3 kV substation in Venezuela. ANN's forecasted results are compared with an exponential smoothing load forecasting procedure.
2015 IEEE Workshop on Power Electronics and Power Quality Applications (PEPQA), 2015
—This work presents a comparison of three techniques for parameter estimation of the induction ma... more —This work presents a comparison of three techniques for parameter estimation of the induction machine dynamic model. The first estimation method is based on measurements with the rotor at standstill while several single phase voltage sources are applied at different frequencies. The second method is based on obtaining the instantaneous measurements of voltages and currents during a direct start-up in no load or load condition. To validate the results obtained in each one of these tests, conventional estimation methods are applied to a wound rotor induction machine, according to international standards. The estimation methods are verified using simulations. The obtained results will allow to analyze the accuracy of both methods, and their applicability in industrial environments. The analysis shows the practical conditions where each one of these methods can be applied successfully.
2018 IEEE Third Ecuador Technical Chapters Meeting (ETCM), 2018
This paper presents an evaluation of the effects of variable frequency drives (VFDs) on induction... more This paper presents an evaluation of the effects of variable frequency drives (VFDs) on induction machines efficiency. For this purpose, an experimental evaluation using international standards IEEE 112, IEC 60034-2-1 and IEC 60034-2-3 (draft version), was set up. These standards estimated the induction machine's efficiency based on a loss segregation approach to consider the stator, core, friction, rotor, stray-load, and additional losses contribution. Additionally, the machine's losses were studied using a time-stepping, 2D, Finite Element Method (FEM) analysis on the open-source software Gmsh-GetDP. This analysis used voltage waveforms suggested by IEC 60034-2-3 and a motor design with the same rated characteristics to those used in the experimental stage.
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Papers by Johnny W Rengifo Santana