The Experts below are selected from a list of 39858 Experts worldwide ranked by ideXlab platform
Ralph Kennel - One of the best experts on this subject based on the ideXlab platform.
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operating Point dependent variable Switching Point predictive current control for pmsm drives
2019 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE), 2019Co-Authors: Sebastian Wendel, Petros Karamanakos, Armin Dietz, Ralph KennelAbstract:This contribution presents a direct model predictive current control approach that achieves favorable performance during transients while minimizing the torque and current ripples at steady-state operation by increasing the granularity at which Switching can be performed. To meet the control goals, an optimization problem is solved in real-time that decides whether only one discrete voltage space vector or a combination of two is selected. In the latter case, a variable Switching Point, i.e., a time instant within the control interval at which the converter switches change state, is computed. The proposed method is advantageous, e.g., for electric drives in machine tools, in which, depending on the operating Point, fast dynamics and a low torque ripple are important. The approach is evaluated at the example of a two-level voltage source inverter driving a permanent magnet synchronous machine.
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a variable Switching Point predictive current control strategy for quasi z source inverters
IEEE Transactions on Industry Applications, 2018Co-Authors: Petros Karamanakos, Ayman Ayad, Ralph KennelAbstract:This paper presents a variable Switching Point predictive current control (VSP $^2$ CC) for the quasi-Z-source inverter (qZSI). The proposed VSP $^2$ CC aims to remove the output current error on the ac side, as well as the inductor current and capacitor voltage errors of the quasi-Z-source network on the dc side of the converter. Unlike the previously presented direct model predictive control (MPC) strategies for the qZSI, the proposed control scheme can directly apply the Switching signals not only at the discrete time instants, but at any time instant within the sampling interval. Consequently, the shoot-through state can be applied for a shorter time than the sampling interval, resulting in lower output and inductor currents ripples. Experimental results based on field programmable gate array are provided to verify the effectiveness of the introduced control method. As it is shown, the proposed method leads to lower inductor current ripples and less output current total harmonic distortion when compared with the conventional direct MPC.
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variable Switching Point predictive torque control with extended prediction horizon
International Conference on Industrial Technology, 2015Co-Authors: Ilias Alevras, Petros Karamanakos, S N Manias, Ralph KennelAbstract:This paper introduces the extension of the prediction horizon in the one-step variable Switching Point predictive torque control (VSP2TC). Even though in the majority of power electronics applications using model predictive control (MPC) based schemes, a prediction horizon of one suffices, the use of longer prediction horizons offers substantial performance benefits. To highlight this, the proposed algorithm is applied to a low voltage (LV) drive system, which comprises a two-level inverter and an induction machine (IM). As it is shown, by extending the prediction horizon, important drive quality indices, such as the torque ripple, and the total harmonic distortion (THD) of the stator currents are reduced. However, the computational effort required for solving the formulated optimization problem in real time can be overwhelming. The implementation of a branch-and-bound technique is introduced to front this tricky matter. Simulation results verify the performance of the presented control strategy.
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variable Switching Point predictive torque control of induction machines
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2014Co-Authors: Petros Karamanakos, S N Manias, Ralph Kennel, Peter Stolze, Hendrik Du Toit MoutonAbstract:This paper introduces an approach to include a variable Switching time Point into predictive torque control (PTC). In PTC, the Switching frequency is limited by the sampling frequency; its theoretical maximum value is half the sampling frequency. However, in reality the Switching frequency is lower than this value, and thus, high current and torque ripples occur compared with modulator-based control methods. In order to overcome this, an optimization problem is formulated and solved in real time. Thereby, apart from the regulation of the torque and the flux magnitude to their references, an additional control objective should be met: the minimization of the torque ripple. To do so, the time Point at which the switches of the inverter should change state is calculated. Further advantages of the proposed method include the design flexibility and great performance during transients. Experimental results that verify the performance of the presented control strategy are included.
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heuristic variable Switching Point predictive current control for the three level neutral Point clamped inverter
2013 IEEE International Symposium on Sensorless Control for Electrical Drives and Predictive Control of Electrical Drives and Power Electronics (SLED , 2013Co-Authors: Peter Stolze, Petros Karamanakos, Ralph Kennel, Males Tomlinson, Toit Mouton, S N ManiasAbstract:This paper presents a variable Switching Point predictive current control (VSP2CC) method for induction machines (IMs) driven by a three-level neutral Point clamped (NPC) inverter with a heuristic preselection of the optimal voltage vector. Enumeration-based model predictive control (MPC) methods are very simple, easy to understand and, in general, offer the possibility to control any nonlinear system with arbitrary user-defined terms in the cost function. However, the two most important drawbacks are the increased computational effort which is required and the high ripples on the controlled variables which limit the applicability of these methods. These high ripples result from the fact that in enumeration-based MPC algorithms the actuating variable can only be changed at the beginning of a sampling interval. However, by changing the applied voltage vector within the sampling interval, a voltage vector can be applied for a shorter time than one sample, which results in a reduced ripple. Since this strategy leads to an additional overhead which is crucial especially for multilevel inverters, it is combined with a heuristic preselection of the optimal voltage vector to reduce the calculation effort. Experimental results are provided to verify the proposed strategy. Furthermore, it will be shown experimentally that a conventional enumeration-based MPC method will lead to very low Switching frequencies and high current ripples at low machine speeds; this significant drawback can be overcome with the proposed VSP2CC strategy.
Petros Karamanakos - One of the best experts on this subject based on the ideXlab platform.
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operating Point dependent variable Switching Point predictive current control for pmsm drives
2019 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE), 2019Co-Authors: Sebastian Wendel, Petros Karamanakos, Armin Dietz, Ralph KennelAbstract:This contribution presents a direct model predictive current control approach that achieves favorable performance during transients while minimizing the torque and current ripples at steady-state operation by increasing the granularity at which Switching can be performed. To meet the control goals, an optimization problem is solved in real-time that decides whether only one discrete voltage space vector or a combination of two is selected. In the latter case, a variable Switching Point, i.e., a time instant within the control interval at which the converter switches change state, is computed. The proposed method is advantageous, e.g., for electric drives in machine tools, in which, depending on the operating Point, fast dynamics and a low torque ripple are important. The approach is evaluated at the example of a two-level voltage source inverter driving a permanent magnet synchronous machine.
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a variable Switching Point predictive current control strategy for quasi z source inverters
IEEE Transactions on Industry Applications, 2018Co-Authors: Petros Karamanakos, Ayman Ayad, Ralph KennelAbstract:This paper presents a variable Switching Point predictive current control (VSP $^2$ CC) for the quasi-Z-source inverter (qZSI). The proposed VSP $^2$ CC aims to remove the output current error on the ac side, as well as the inductor current and capacitor voltage errors of the quasi-Z-source network on the dc side of the converter. Unlike the previously presented direct model predictive control (MPC) strategies for the qZSI, the proposed control scheme can directly apply the Switching signals not only at the discrete time instants, but at any time instant within the sampling interval. Consequently, the shoot-through state can be applied for a shorter time than the sampling interval, resulting in lower output and inductor currents ripples. Experimental results based on field programmable gate array are provided to verify the effectiveness of the introduced control method. As it is shown, the proposed method leads to lower inductor current ripples and less output current total harmonic distortion when compared with the conventional direct MPC.
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variable Switching Point predictive torque control with extended prediction horizon
International Conference on Industrial Technology, 2015Co-Authors: Ilias Alevras, Petros Karamanakos, S N Manias, Ralph KennelAbstract:This paper introduces the extension of the prediction horizon in the one-step variable Switching Point predictive torque control (VSP2TC). Even though in the majority of power electronics applications using model predictive control (MPC) based schemes, a prediction horizon of one suffices, the use of longer prediction horizons offers substantial performance benefits. To highlight this, the proposed algorithm is applied to a low voltage (LV) drive system, which comprises a two-level inverter and an induction machine (IM). As it is shown, by extending the prediction horizon, important drive quality indices, such as the torque ripple, and the total harmonic distortion (THD) of the stator currents are reduced. However, the computational effort required for solving the formulated optimization problem in real time can be overwhelming. The implementation of a branch-and-bound technique is introduced to front this tricky matter. Simulation results verify the performance of the presented control strategy.
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variable Switching Point predictive torque control of induction machines
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2014Co-Authors: Petros Karamanakos, S N Manias, Ralph Kennel, Peter Stolze, Hendrik Du Toit MoutonAbstract:This paper introduces an approach to include a variable Switching time Point into predictive torque control (PTC). In PTC, the Switching frequency is limited by the sampling frequency; its theoretical maximum value is half the sampling frequency. However, in reality the Switching frequency is lower than this value, and thus, high current and torque ripples occur compared with modulator-based control methods. In order to overcome this, an optimization problem is formulated and solved in real time. Thereby, apart from the regulation of the torque and the flux magnitude to their references, an additional control objective should be met: the minimization of the torque ripple. To do so, the time Point at which the switches of the inverter should change state is calculated. Further advantages of the proposed method include the design flexibility and great performance during transients. Experimental results that verify the performance of the presented control strategy are included.
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heuristic variable Switching Point predictive current control for the three level neutral Point clamped inverter
2013 IEEE International Symposium on Sensorless Control for Electrical Drives and Predictive Control of Electrical Drives and Power Electronics (SLED , 2013Co-Authors: Peter Stolze, Petros Karamanakos, Ralph Kennel, Males Tomlinson, Toit Mouton, S N ManiasAbstract:This paper presents a variable Switching Point predictive current control (VSP2CC) method for induction machines (IMs) driven by a three-level neutral Point clamped (NPC) inverter with a heuristic preselection of the optimal voltage vector. Enumeration-based model predictive control (MPC) methods are very simple, easy to understand and, in general, offer the possibility to control any nonlinear system with arbitrary user-defined terms in the cost function. However, the two most important drawbacks are the increased computational effort which is required and the high ripples on the controlled variables which limit the applicability of these methods. These high ripples result from the fact that in enumeration-based MPC algorithms the actuating variable can only be changed at the beginning of a sampling interval. However, by changing the applied voltage vector within the sampling interval, a voltage vector can be applied for a shorter time than one sample, which results in a reduced ripple. Since this strategy leads to an additional overhead which is crucial especially for multilevel inverters, it is combined with a heuristic preselection of the optimal voltage vector to reduce the calculation effort. Experimental results are provided to verify the proposed strategy. Furthermore, it will be shown experimentally that a conventional enumeration-based MPC method will lead to very low Switching frequencies and high current ripples at low machine speeds; this significant drawback can be overcome with the proposed VSP2CC strategy.
S N Manias - One of the best experts on this subject based on the ideXlab platform.
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variable Switching Point predictive torque control with extended prediction horizon
International Conference on Industrial Technology, 2015Co-Authors: Ilias Alevras, Petros Karamanakos, S N Manias, Ralph KennelAbstract:This paper introduces the extension of the prediction horizon in the one-step variable Switching Point predictive torque control (VSP2TC). Even though in the majority of power electronics applications using model predictive control (MPC) based schemes, a prediction horizon of one suffices, the use of longer prediction horizons offers substantial performance benefits. To highlight this, the proposed algorithm is applied to a low voltage (LV) drive system, which comprises a two-level inverter and an induction machine (IM). As it is shown, by extending the prediction horizon, important drive quality indices, such as the torque ripple, and the total harmonic distortion (THD) of the stator currents are reduced. However, the computational effort required for solving the formulated optimization problem in real time can be overwhelming. The implementation of a branch-and-bound technique is introduced to front this tricky matter. Simulation results verify the performance of the presented control strategy.
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variable Switching Point predictive torque control of induction machines
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2014Co-Authors: Petros Karamanakos, S N Manias, Ralph Kennel, Peter Stolze, Hendrik Du Toit MoutonAbstract:This paper introduces an approach to include a variable Switching time Point into predictive torque control (PTC). In PTC, the Switching frequency is limited by the sampling frequency; its theoretical maximum value is half the sampling frequency. However, in reality the Switching frequency is lower than this value, and thus, high current and torque ripples occur compared with modulator-based control methods. In order to overcome this, an optimization problem is formulated and solved in real time. Thereby, apart from the regulation of the torque and the flux magnitude to their references, an additional control objective should be met: the minimization of the torque ripple. To do so, the time Point at which the switches of the inverter should change state is calculated. Further advantages of the proposed method include the design flexibility and great performance during transients. Experimental results that verify the performance of the presented control strategy are included.
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heuristic variable Switching Point predictive current control for the three level neutral Point clamped inverter
2013 IEEE International Symposium on Sensorless Control for Electrical Drives and Predictive Control of Electrical Drives and Power Electronics (SLED , 2013Co-Authors: Peter Stolze, Petros Karamanakos, Ralph Kennel, Males Tomlinson, Toit Mouton, S N ManiasAbstract:This paper presents a variable Switching Point predictive current control (VSP2CC) method for induction machines (IMs) driven by a three-level neutral Point clamped (NPC) inverter with a heuristic preselection of the optimal voltage vector. Enumeration-based model predictive control (MPC) methods are very simple, easy to understand and, in general, offer the possibility to control any nonlinear system with arbitrary user-defined terms in the cost function. However, the two most important drawbacks are the increased computational effort which is required and the high ripples on the controlled variables which limit the applicability of these methods. These high ripples result from the fact that in enumeration-based MPC algorithms the actuating variable can only be changed at the beginning of a sampling interval. However, by changing the applied voltage vector within the sampling interval, a voltage vector can be applied for a shorter time than one sample, which results in a reduced ripple. Since this strategy leads to an additional overhead which is crucial especially for multilevel inverters, it is combined with a heuristic preselection of the optimal voltage vector to reduce the calculation effort. Experimental results are provided to verify the proposed strategy. Furthermore, it will be shown experimentally that a conventional enumeration-based MPC method will lead to very low Switching frequencies and high current ripples at low machine speeds; this significant drawback can be overcome with the proposed VSP2CC strategy.
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variable Switching Point predictive torque control
International Conference on Industrial Technology, 2013Co-Authors: Petros Karamanakos, S N Manias, Ralph Kennel, Peter Stolze, Toit MoutonAbstract:In this paper an approach to include a variable Switching time Point into predictive torque control (PTC) is introduced. In PTC the Switching frequency is limited by the sampling frequency; its theoretical maximum value is half the sampling frequency. In reality, however, the Switching frequency is lower than this value, resulting in high current and torque ripples compared to modulator-based control methods. In order to overcome this an optimization problem is formulated and solved in real-time. The goal is to find the time Point at which the switches of the inverter should change state in order to not only achieve the regulation of the torque and the flux magnitude to their references, but also the minimization of the torque ripple. Further advantages of the proposed method include the design flexibility and great performance during transients. Experimental results that verify the performance of the presented control strategy are included.
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variable Switching Point predictive torque control for the three level neutral Point clamped inverter
15th Conference on Power Electronics and Applications EPE'13 ECCE Europe, 2013Co-Authors: Peter Stolze, Petros Karamanakos, S N Manias, Ralph Kennel, Toit MoutonAbstract:In this paper the recently introduced control strategy referred as variable Switching Point predictive torque control (VSP2TC) is employed to control a three-level neutral Point clamped (NPC) voltage source inverter driving an induction machine (IM). Based on a predictive torque control (PTC) scheme, the controller aims to reduce the high current and torque ripples that occur. In order to actualize this, a variable Switching Point is calculated based on an optimization problem formulated to reduce the torque ripple. At this Switching Point the switches of the inverter change their state to meet all the control objectives, i.e. minimization of the torque ripple, regulation of the torque and the flux magnitude to their references, and balancing of the neutral Point potential. Experimental results that verify the performance of the proposed control algorithm are presented.
Peter Stolze - One of the best experts on this subject based on the ideXlab platform.
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variable Switching Point predictive torque control of induction machines
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2014Co-Authors: Petros Karamanakos, S N Manias, Ralph Kennel, Peter Stolze, Hendrik Du Toit MoutonAbstract:This paper introduces an approach to include a variable Switching time Point into predictive torque control (PTC). In PTC, the Switching frequency is limited by the sampling frequency; its theoretical maximum value is half the sampling frequency. However, in reality the Switching frequency is lower than this value, and thus, high current and torque ripples occur compared with modulator-based control methods. In order to overcome this, an optimization problem is formulated and solved in real time. Thereby, apart from the regulation of the torque and the flux magnitude to their references, an additional control objective should be met: the minimization of the torque ripple. To do so, the time Point at which the switches of the inverter should change state is calculated. Further advantages of the proposed method include the design flexibility and great performance during transients. Experimental results that verify the performance of the presented control strategy are included.
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heuristic variable Switching Point predictive current control for the three level neutral Point clamped inverter
2013 IEEE International Symposium on Sensorless Control for Electrical Drives and Predictive Control of Electrical Drives and Power Electronics (SLED , 2013Co-Authors: Peter Stolze, Petros Karamanakos, Ralph Kennel, Males Tomlinson, Toit Mouton, S N ManiasAbstract:This paper presents a variable Switching Point predictive current control (VSP2CC) method for induction machines (IMs) driven by a three-level neutral Point clamped (NPC) inverter with a heuristic preselection of the optimal voltage vector. Enumeration-based model predictive control (MPC) methods are very simple, easy to understand and, in general, offer the possibility to control any nonlinear system with arbitrary user-defined terms in the cost function. However, the two most important drawbacks are the increased computational effort which is required and the high ripples on the controlled variables which limit the applicability of these methods. These high ripples result from the fact that in enumeration-based MPC algorithms the actuating variable can only be changed at the beginning of a sampling interval. However, by changing the applied voltage vector within the sampling interval, a voltage vector can be applied for a shorter time than one sample, which results in a reduced ripple. Since this strategy leads to an additional overhead which is crucial especially for multilevel inverters, it is combined with a heuristic preselection of the optimal voltage vector to reduce the calculation effort. Experimental results are provided to verify the proposed strategy. Furthermore, it will be shown experimentally that a conventional enumeration-based MPC method will lead to very low Switching frequencies and high current ripples at low machine speeds; this significant drawback can be overcome with the proposed VSP2CC strategy.
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variable Switching Point predictive torque control
International Conference on Industrial Technology, 2013Co-Authors: Petros Karamanakos, S N Manias, Ralph Kennel, Peter Stolze, Toit MoutonAbstract:In this paper an approach to include a variable Switching time Point into predictive torque control (PTC) is introduced. In PTC the Switching frequency is limited by the sampling frequency; its theoretical maximum value is half the sampling frequency. In reality, however, the Switching frequency is lower than this value, resulting in high current and torque ripples compared to modulator-based control methods. In order to overcome this an optimization problem is formulated and solved in real-time. The goal is to find the time Point at which the switches of the inverter should change state in order to not only achieve the regulation of the torque and the flux magnitude to their references, but also the minimization of the torque ripple. Further advantages of the proposed method include the design flexibility and great performance during transients. Experimental results that verify the performance of the presented control strategy are included.
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variable Switching Point predictive torque control for the three level neutral Point clamped inverter
15th Conference on Power Electronics and Applications EPE'13 ECCE Europe, 2013Co-Authors: Peter Stolze, Petros Karamanakos, S N Manias, Ralph Kennel, Toit MoutonAbstract:In this paper the recently introduced control strategy referred as variable Switching Point predictive torque control (VSP2TC) is employed to control a three-level neutral Point clamped (NPC) voltage source inverter driving an induction machine (IM). Based on a predictive torque control (PTC) scheme, the controller aims to reduce the high current and torque ripples that occur. In order to actualize this, a variable Switching Point is calculated based on an optimization problem formulated to reduce the torque ripple. At this Switching Point the switches of the inverter change their state to meet all the control objectives, i.e. minimization of the torque ripple, regulation of the torque and the flux magnitude to their references, and balancing of the neutral Point potential. Experimental results that verify the performance of the proposed control algorithm are presented.
B Forster - One of the best experts on this subject based on the ideXlab platform.
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a chopped hall sensor with small jitter and programmable true power on function
IEEE Journal of Solid-state Circuits, 2005Co-Authors: Mario Motz, Dieter Draxelmayr, Tobias Werth, B ForsterAbstract:A chopped Hall sensor for camshaft applications is presented which provides a programmable "True Power-on" Switching level effective after the power-up phase. The proposed chopping technique and self-compensation methods for temperature drift and technology spread provide a correct output state immediately after power-on even at zero speed of the target wheel. The circuits improve the magnetic offsets from 5 to 10 mT to below 200 /spl mu/T in a bandwidth of 30 kHz and stabilize the spread of the magnetic Switching Points from 20% to <2% in a temperature range from -40/spl deg/C to 175/spl deg/C. The novel combination of chopping and enhanced digital self-calibration algorithm adjusts the magnetic Switching Point and improves phase accuracy to <0.5/spl deg/, independent of air gap variations between sensor and wheel. An end-of-line calibration for the customer is implemented using surface micromachined cavity fuses which offer a reliable function higher than 195/spl deg/C.
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a chopped hall sensor with small jitter and programmable true power on function
European Solid-State Circuits Conference, 2005Co-Authors: Mario Motz, Dieter Draxelmayr, Tobias Werth, B ForsterAbstract:A chopped Hall sensor for camshaft applications is presented which provides a programmable True Power-on Switching level effective after the power-up phase. The proposed chopping technique and self-compensation methods for temperature drift and technology spread provide a correct output state immediately after power-on even at zero speed of the target wheel. The circuits improve the magnetic offsets from 5 to 10 mT to below 200 μT in a bandwidth of 30 kHz and stabilize the spread of the magnetic Switching Points from 20% to <2% in a temperature range from -40°C to 175 °C. The novel combination of chopping and enhanced digital self-calibration algorithm adjusts the magnetic Switching Point and improves phase accuracy to < 0.5°, independent of air gap variations between sensor and wheel. An end-of-line calibration for the customer is implemented using surface micromachined cavity fuses which offer a reliable function higher than 195 °C.
