EPE Association: EPE 2009 - Subtopic 11-4 - DS: 'Adjustable Speed Drive Systems'

EPE 2009 - Subtopic 11-4 - DS: 'Adjustable Speed Drive Systems'
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2009 - Conference > EPE 2009 - Topic 11: 'Adjustable Speed Drives' > EPE 2009 - Subtopic 11-4 - DS: 'Adjustable Speed Drive Systems'

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   A Modified DTC for Matrix Converter Drives Using Two Switching Configurations
By DAN XIAO, MUHAMMED RAHMAN [View]
[Download]

Abstract: This paper presents a modified direct torque control scheme for matrix converter drives. This method allows a reduction of the harmonic content of the input current without any negative effect on the drive performance and its simplicity. By using two switching configurations at each cycle, the synthesis of the input current vector is more accurate than the previous method at the same sampling period, allowing the instantaneous control of input power factor without the input displacement angle estimator, the low-pass filter or the input power factor hysteresis comparator, which are required in the classical switching table based direct torque control scheme for matrix converters. A two-level torque hysteresis comparator is adopted to reduce the torque ripple at high and medium speeds, an active vector selected to increase the torque while a zero vector to decrease the torque. Moreover, applying two switching patterns provides a higher switching frequency seen from the input side, with effect on reducing the input filter size. A comparison between the classical direct torque control and the proposed scheme is carried out. Simulation and experimental results are shown to demonstrate the effectiveness and improvement of the novel direct torque control method.

   A Novel Approach to Eliminating Common-Mode Voltages and Leakage Currents with a Small Capacity Auxiliary Inverter
By Masafumi KIKUCHI, Hisao KUBOTA [View]
[Download]

Abstract: This paper presents a dual-bridge inverter approach to eliminate the motor common-mode voltage. This inverter which consists of two inverters to be connected in parallel does not generate the common-mode voltage, and can drive standard three-phase three-wire induction motors. Additionally, because one inverter does not output active power, the capacity of the inverter is very small. The effectiveness of the proposed method is verified experimentally.

   A System-Level Approach to the Optimal Dimensioning of Induction-Motor Variable-Frequency Drives
By ALBERTO TESSAROLO, DAVIDE GIULIVO, MARIO MEZZAROBBA [View]
[Download]

Abstract: In the design of induction motor adjustable-speed drives, the same efficiency and performance requirements can be achieved with different choices as far as the motor and the inverter individual size is concerned. Depending on the specific functions that relate motor and inverter size to their respective cost, each choice is expected to result in a different overall drive cost. This paper presents a design algorithm that enables to dimension the motor and the inverter so as to achieve a minimum of the overall drive cost, under efficiency and performance constraints. As a study case, the algorithm is applied to the optimal dimensioning of a 600 kW induction motor drive designed to operate over a 600Ã·1000 rpm speed-range with a 235\% temporary overload capability and a minimum motor efficiency of 94\% at 600 rpm and 600 kW.

   Analysis and Simulation of a Novel Load-Commutated Inverter Drive Based on a Symmetrical Five-Phase Synchronous Motor
By ALBERTO TESSAROLO, SIMONE CASTELLAN, ROBERTO MENIS [View]
[Download]

Abstract: In todayâ€™s electrical drives, the use of more than three-phases to implement the electrical machine stator winding is a frequently adopted provision to enhance system power rating and fault tolerance. In VSI-fed electrical machines, multi-phase windings are adopted in both their symmetrical structures (with n equally distributed phases, supplied by a single n-phase inverter) and in their multiple threephase arrangements (with two or more displaced three-phase windings, each supplied by an inverter). On the other hand, in CSI drives, based on synchronous motors and Load Commutated Inverters (LCIs), the only multi-phase topology practically used consists of two three-phase windings, displaced by 30 electrical degrees, each fed by an LCI. This paper investigates an alternative, symmetrical multiphase LCI drive topology based on a five-phase motor supplied by a five-phase inverter. Both the motor and the inverter are accurately modeled in the Matlab/Simulink environment to study their combined behavior through numeric simulations, both in normal and faulty operating conditions. Simulation results are presented in order to highlight the pros and contras of the proposed topology with respect to the existing ones, taking performance and fault-tolerance features into account.

   Effect of Motor Current Sampling Method on Motor Torque Ripple in High Torque Permanent Magnet Synchronous Machine Drives
By Duro BASIC [View]
[Download]

Abstract: High torque low speed direct drive permanent magnetic synchronous machines (PMSM) powered by variable speed drives are increasingly used in applications traditionally reserved for standard induction motors with gear-boxes. Our application experience shows that in such motors resonant frequency of the common mode current path can have unusually low value (comparable with the inverter switching frequency) which is for at least a decade lower than that normally expected in standard induction machines. Thus the drive inverter switchings can excite large common mode currents which appear as a strong low frequency disturbance in the motor currents causing significant errors in the motor current measurements and related motor torque ripple induced by the drive itself. Rejection of such strong low frequency disturbance in the motor current measurements appears to be far more problematic that the rejection of the standard motor current switching ripple or high frequency noise caused by the inverter switching. Our goal in this paper is to point out to this issue and investigate practically available options appropriate for its mitigation. It will be shown and experimentally demonstrated that the averaging sampling method is suitable for this purpose.

   Improved Techniques of Restrained Search Predictive Control for Multiphase Drives
By MARIO DURAN, FEDERICO BARRERO, SERGIO TORAL, MANUEL ARAHAL, joel PRIETO [View]
[Download]

Abstract: Predictive control is becoming an alternative to standard vector control or direct torque control in electrical drives due to its fast torque response and design flexibility. In multiphase drives, where the complexity of the modulation techniques and control schemes is higher, the predictive control has proved to be a promising alternative. The main shortcoming of the standard predictive control (SPC) in multiphase drives is the high computational cost caused by the increased number of switching state possibilities. This work proposes a restrained search predictive control (RSPC) where some switching states are discarded by imposing several restrictions. The steady and transient states are explored, also examining the unbalance in the switching frequency of the voltage source inverter (VSI) legs and the effect of allowing submodulation. The advantages of the proposed control are discussed and the viability is confirmed by simulation.

   Induction motor encoderless control associated to a sinus filter for industrial high power application
By Franck TERRIEN, Sami SIALA [View]
[Download]

Abstract: This paper deals with the control of a medium voltage 3 level inverter supplying a High speed induction machine via a Sinus filter. The sinus filter dynamic impacts the global model, and induce a resonance frequency, that has to be managed to ensure the global stability. Two control methods are presented with site experimental results of 6MW 10000rpm application.

   Investigation of Harmonic Filtering for the State-of-the-art Variable Speed Drives
By Behrooz BAHRANI, Roman GRINBERG [View]
[Download]

Abstract: State-of-the-art low voltage (LV) medium and high power variable speed drives are voltage source converters. Frequently, frond-end stage is a diode rectifier. To reduce the amount of input current harmonics multi-pulse rectifiers are used. Due to the high cost of active front-end and the specific transformer requirements of multi-pulse rectification, alternative harmonic filtering solutions are sought. In this paper, the performance of several techniques, proposed for harmonic filtering, is analyzed in view of LV drive application. It is shown that regardless of the proposed solution, harmonic filtering presents additional design requirements to the drive system and compliance with harmonic standards challenges the harmonic filter design in terms of capacitor current capability.

   Lyapunov Based Predictive DTC Algorithm for Induction Motors
By Miran RODIC, Karel JEZERNIK [View]
[Download]

Abstract: A model predictive DTC algorithm used for the Lyapunov stability function based DTC of induction motor control is presented in the paper. It is proposed as an alternative to the classical approaches based on the look-up tables, where the contribution of electromotive force is not considered. An appropriate Lyapunov function is chosen and, based on its derivative, optimal stator voltage vector is determined to be applied to the induction motor by the inverter. Also an appropriate torque and flux observer is proposed. The approach can be applied by either the DSP- or FPGA-based hardware making the advantage of the possible parallelization of computing. Both, simulation and experimental results are provided in order to demonstrate the performance.

   On the selection of single phase induction motors for low cost speed controlled drives
By Klaus KRISCHAN, Guenther DANNERER, roland SEEBACHER [View]
[Download]

Abstract: Operating single phase induction motors across a wide range of speed and load with high efficiency is still of interest. In the paper at hand the suitability of several different capacitor run single phase induction machines for Phase Control, Integral (Half) Cycle Control or Integral Switched Cycle Control is investigated. The induction machineâ€™s modelâ€™s electrical and mechanical parameters are estimated and simulations are carried out in order to investigate the influence of the parameters on total input power, torque and losses. Measurements are carried out recording rotor speed and total input power comparing Phase Control and Integral Switched Cycle Control at approximately the same operating points. From these data a simple method is derived that can be used for selecting machines for low cost speed controlled drives. The experimental results verify the proposed method.

   Prediction of Local Instabilities caused by Inverter Dead Time in AC drive
By Veran VASIC, Darko MARCETIC, Djura OROS, Filip KULIC [View]
[Download]

Abstract: Undesired low-frequency self-sustained speed oscillations are encountered in fan, compressor and pump drives utilizing open-loop frequency-controlled induction motor drives. Discontinuous rectifier current at light loads and the dead-time of the inverter switches are the main sources of such oscillations. This paper proposes a concise analytical method to predict the risk of self-sustained oscillations due to these two phenomena.

   Sensorless AC Drive Control with LC Filter
By Jaroslaw GUZINSKI [View]
[Download]

Abstract: The paper presents the speed sensorless control of the induction motor in the system with the voltage inverter and LC filter. The LC filter is used to smooth the motor currents and voltages. In the control system the non-linear control method is used. For the state variables estimation the disturbance observer is implemented. Because of the voltage drop and phase shift caused by the LC filter the observer and the control system were modified. In the control system a multi-loop feedback controller was used. The modified state variables observer was developed taking into account the LC filter model. With the presented drive the speed sensors is not required. All the controls are based on measurement of the inverter output currents and dc input voltage. The proposed speed sensorless drive with the asynchronous motor was verified by the simulation and the experimental tests.

   Speed Anti-Windup PI strategies review for Field Oriented Control of Permanent Magnet Synchronous Machines Servo Drives with Matrix Converters
By Jordi ESPINA, Antoni ARIAS, Carlos ORTEGA, Josep BALCELLS, Samuel GALCERAN [View]
[Download]

Abstract: When facing real systems PI tuning, the plant is modeled disregarding its physical limitations. Consequently, the PI output may increase indefinitely its value; phenomenon called Windup. This paper presents a review and a comparison between different Anti-Windup PI strategies used in speed motion and position control for Matrix Converter PMSM servo drives.

   Speed Control of Torsional Drive Systems with Backlash
By Soenke THOMSEN, Friedrich W. FUCHS [View]
[Download]

Abstract: This paper presents the design, analysis and comparison of the conventional PI-control to two state space controllers for speed control of drive systems with elastically coupled loads. A state space controller of fourth order which considers only the mechanical system and a state space controller of fifth order which takes an approximation of the electrical system into account are analyzed. Thereby, the effects of backlash in the drive are analyzed in each control. State space control yields a high performance, is able to damp torsional oscillations effectively and to reduce backlash effects. Measurement results confirm these statements.

   Synchronous drives with field oriented vector control and their industrial implementation
By Alexander WEINGER, Dmitry BELIAEV, Evgeny ILYIN, Arthur SHATOKHIN [View]
[Download]

Abstract: Field oriented control doesnâ€™t correspond to features of synchronous motor as good as it does to induction motor. Special control algorithm is proposed to provide operation, suitable for mass high-power drives. The solution is implemented and tested in two fan drives, 3.15 MW each, now in operation at a diamond mine in North-East Siberia.

   Voltage-Oriented Vector Control of Induction Motor: Principle and Dynamic Performance Improvement
By Yongdong LI [View]
[Download]

Abstract: This paper deals with the performance improvement of the Voltage-Oriented Vector Control(VOC) of induction motor which presents the merits of constant stator flux control, simple calculation and easy implementation. In this method, the d-axis of synchronous reference frame is oriented in the direction of the stator voltage vector, and then a control strategy specific for the induction motor is obtained. Based on the previous work, much progress has been made recently to get better dynamic performance, including the improved system structure and a novel stator flux estimator. Simulation and experimental results show that by knowing only a few parameters of the induction motor such as Rs and J, the flux and torque can be controlled independently, and a simple as well as high-performance speed control can be achieved while avoiding the complex coordinate transformation in traditional vector control methods.

   Z-Source Drive Inverter using modified SVPWM for low Output Voltage and regenerating Operation
By Moritz ZIMMERMANN, Martin LECHLER, Bernhard PIEPENBREIER [View]
[Download]

Abstract: Z-source inverters, consisting of both inductors and capacitors as DC-link components, provide unique boost capability with simple structure needing no additional switching elements. Due to complex operation modes of the Z-source inverter compared to a conventional inverter, boost operation, light load and regenerating operation cannot be achieved using common space-vector pulse width modulation. This paper proposes a modified SVPWM, derived from the known equations, to overcome this limitation. Besides, equations to control the output behaviour for all operating modes, such as buck, boost and regenerating operation, are given in detail. Finally, experimental results are presented.

   Zero Body Diode Conduction Time in Variable Speed Drive Converter Systems
By Matthias ROSE, JÃ¶rg KRUPAR, Henry GÃœLDNER [View]
[Download]

Abstract: This paper describes a digital gate control approach for variable speed motor drive systems. The presented approach reduces body diode conduction time to zero without generation of cross conduction. The method uses a measurement impedance in series to the power devices of the converter system. This allows the direct detection of the current commutation interval and the load current direction in every half-bridge. With application of this approach we achieved an improved efficiency and electromagnetic behavior by the avoidance of body diode conduction and reverse recovery. The duration of a switching transition is minimized.

EPE 2009 - Subtopic 11-4 - DS: 'Adjustable Speed Drive Systems'
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2009 - Conference > EPE 2009 - Topic 11: 'Adjustable Speed Drives' > EPE 2009 - Subtopic 11-4 - DS: 'Adjustable Speed Drive Systems'
	[return to parent folder]

	A Modified DTC for Matrix Converter Drives Using Two Switching Configurations By DAN XIAO, MUHAMMED RAHMAN	[View] [Download]
Abstract: This paper presents a modified direct torque control scheme for matrix converter drives. This method allows a reduction of the harmonic content of the input current without any negative effect on the drive performance and its simplicity. By using two switching configurations at each cycle, the synthesis of the input current vector is more accurate than the previous method at the same sampling period, allowing the instantaneous control of input power factor without the input displacement angle estimator, the low-pass filter or the input power factor hysteresis comparator, which are required in the classical switching table based direct torque control scheme for matrix converters. A two-level torque hysteresis comparator is adopted to reduce the torque ripple at high and medium speeds, an active vector selected to increase the torque while a zero vector to decrease the torque. Moreover, applying two switching patterns provides a higher switching frequency seen from the input side, with effect on reducing the input filter size. A comparison between the classical direct torque control and the proposed scheme is carried out. Simulation and experimental results are shown to demonstrate the effectiveness and improvement of the novel direct torque control method.

	A Novel Approach to Eliminating Common-Mode Voltages and Leakage Currents with a Small Capacity Auxiliary Inverter By Masafumi KIKUCHI, Hisao KUBOTA	[View] [Download]
Abstract: This paper presents a dual-bridge inverter approach to eliminate the motor common-mode voltage. This inverter which consists of two inverters to be connected in parallel does not generate the common-mode voltage, and can drive standard three-phase three-wire induction motors. Additionally, because one inverter does not output active power, the capacity of the inverter is very small. The effectiveness of the proposed method is verified experimentally.

	A System-Level Approach to the Optimal Dimensioning of Induction-Motor Variable-Frequency Drives By ALBERTO TESSAROLO, DAVIDE GIULIVO, MARIO MEZZAROBBA	[View] [Download]
Abstract: In the design of induction motor adjustable-speed drives, the same efficiency and performance requirements can be achieved with different choices as far as the motor and the inverter individual size is concerned. Depending on the specific functions that relate motor and inverter size to their respective cost, each choice is expected to result in a different overall drive cost. This paper presents a design algorithm that enables to dimension the motor and the inverter so as to achieve a minimum of the overall drive cost, under efficiency and performance constraints. As a study case, the algorithm is applied to the optimal dimensioning of a 600 kW induction motor drive designed to operate over a 600Ã·1000 rpm speed-range with a 235\% temporary overload capability and a minimum motor efficiency of 94\% at 600 rpm and 600 kW.

	Analysis and Simulation of a Novel Load-Commutated Inverter Drive Based on a Symmetrical Five-Phase Synchronous Motor By ALBERTO TESSAROLO, SIMONE CASTELLAN, ROBERTO MENIS	[View] [Download]
Abstract: In todayâ€™s electrical drives, the use of more than three-phases to implement the electrical machine stator winding is a frequently adopted provision to enhance system power rating and fault tolerance. In VSI-fed electrical machines, multi-phase windings are adopted in both their symmetrical structures (with n equally distributed phases, supplied by a single n-phase inverter) and in their multiple threephase arrangements (with two or more displaced three-phase windings, each supplied by an inverter). On the other hand, in CSI drives, based on synchronous motors and Load Commutated Inverters (LCIs), the only multi-phase topology practically used consists of two three-phase windings, displaced by 30 electrical degrees, each fed by an LCI. This paper investigates an alternative, symmetrical multiphase LCI drive topology based on a five-phase motor supplied by a five-phase inverter. Both the motor and the inverter are accurately modeled in the Matlab/Simulink environment to study their combined behavior through numeric simulations, both in normal and faulty operating conditions. Simulation results are presented in order to highlight the pros and contras of the proposed topology with respect to the existing ones, taking performance and fault-tolerance features into account.

	Effect of Motor Current Sampling Method on Motor Torque Ripple in High Torque Permanent Magnet Synchronous Machine Drives By Duro BASIC	[View] [Download]
Abstract: High torque low speed direct drive permanent magnetic synchronous machines (PMSM) powered by variable speed drives are increasingly used in applications traditionally reserved for standard induction motors with gear-boxes. Our application experience shows that in such motors resonant frequency of the common mode current path can have unusually low value (comparable with the inverter switching frequency) which is for at least a decade lower than that normally expected in standard induction machines. Thus the drive inverter switchings can excite large common mode currents which appear as a strong low frequency disturbance in the motor currents causing significant errors in the motor current measurements and related motor torque ripple induced by the drive itself. Rejection of such strong low frequency disturbance in the motor current measurements appears to be far more problematic that the rejection of the standard motor current switching ripple or high frequency noise caused by the inverter switching. Our goal in this paper is to point out to this issue and investigate practically available options appropriate for its mitigation. It will be shown and experimentally demonstrated that the averaging sampling method is suitable for this purpose.

	Improved Techniques of Restrained Search Predictive Control for Multiphase Drives By MARIO DURAN, FEDERICO BARRERO, SERGIO TORAL, MANUEL ARAHAL, joel PRIETO	[View] [Download]
Abstract: Predictive control is becoming an alternative to standard vector control or direct torque control in electrical drives due to its fast torque response and design flexibility. In multiphase drives, where the complexity of the modulation techniques and control schemes is higher, the predictive control has proved to be a promising alternative. The main shortcoming of the standard predictive control (SPC) in multiphase drives is the high computational cost caused by the increased number of switching state possibilities. This work proposes a restrained search predictive control (RSPC) where some switching states are discarded by imposing several restrictions. The steady and transient states are explored, also examining the unbalance in the switching frequency of the voltage source inverter (VSI) legs and the effect of allowing submodulation. The advantages of the proposed control are discussed and the viability is confirmed by simulation.

	Induction motor encoderless control associated to a sinus filter for industrial high power application By Franck TERRIEN, Sami SIALA	[View] [Download]
Abstract: This paper deals with the control of a medium voltage 3 level inverter supplying a High speed induction machine via a Sinus filter. The sinus filter dynamic impacts the global model, and induce a resonance frequency, that has to be managed to ensure the global stability. Two control methods are presented with site experimental results of 6MW 10000rpm application.

	Investigation of Harmonic Filtering for the State-of-the-art Variable Speed Drives By Behrooz BAHRANI, Roman GRINBERG	[View] [Download]
Abstract: State-of-the-art low voltage (LV) medium and high power variable speed drives are voltage source converters. Frequently, frond-end stage is a diode rectifier. To reduce the amount of input current harmonics multi-pulse rectifiers are used. Due to the high cost of active front-end and the specific transformer requirements of multi-pulse rectification, alternative harmonic filtering solutions are sought. In this paper, the performance of several techniques, proposed for harmonic filtering, is analyzed in view of LV drive application. It is shown that regardless of the proposed solution, harmonic filtering presents additional design requirements to the drive system and compliance with harmonic standards challenges the harmonic filter design in terms of capacitor current capability.

	Lyapunov Based Predictive DTC Algorithm for Induction Motors By Miran RODIC, Karel JEZERNIK	[View] [Download]
Abstract: A model predictive DTC algorithm used for the Lyapunov stability function based DTC of induction motor control is presented in the paper. It is proposed as an alternative to the classical approaches based on the look-up tables, where the contribution of electromotive force is not considered. An appropriate Lyapunov function is chosen and, based on its derivative, optimal stator voltage vector is determined to be applied to the induction motor by the inverter. Also an appropriate torque and flux observer is proposed. The approach can be applied by either the DSP- or FPGA-based hardware making the advantage of the possible parallelization of computing. Both, simulation and experimental results are provided in order to demonstrate the performance.

	On the selection of single phase induction motors for low cost speed controlled drives By Klaus KRISCHAN, Guenther DANNERER, roland SEEBACHER	[View] [Download]
Abstract: Operating single phase induction motors across a wide range of speed and load with high efficiency is still of interest. In the paper at hand the suitability of several different capacitor run single phase induction machines for Phase Control, Integral (Half) Cycle Control or Integral Switched Cycle Control is investigated. The induction machineâ€™s modelâ€™s electrical and mechanical parameters are estimated and simulations are carried out in order to investigate the influence of the parameters on total input power, torque and losses. Measurements are carried out recording rotor speed and total input power comparing Phase Control and Integral Switched Cycle Control at approximately the same operating points. From these data a simple method is derived that can be used for selecting machines for low cost speed controlled drives. The experimental results verify the proposed method.

	Prediction of Local Instabilities caused by Inverter Dead Time in AC drive By Veran VASIC, Darko MARCETIC, Djura OROS, Filip KULIC	[View] [Download]
Abstract: Undesired low-frequency self-sustained speed oscillations are encountered in fan, compressor and pump drives utilizing open-loop frequency-controlled induction motor drives. Discontinuous rectifier current at light loads and the dead-time of the inverter switches are the main sources of such oscillations. This paper proposes a concise analytical method to predict the risk of self-sustained oscillations due to these two phenomena.

	Sensorless AC Drive Control with LC Filter By Jaroslaw GUZINSKI	[View] [Download]
Abstract: The paper presents the speed sensorless control of the induction motor in the system with the voltage inverter and LC filter. The LC filter is used to smooth the motor currents and voltages. In the control system the non-linear control method is used. For the state variables estimation the disturbance observer is implemented. Because of the voltage drop and phase shift caused by the LC filter the observer and the control system were modified. In the control system a multi-loop feedback controller was used. The modified state variables observer was developed taking into account the LC filter model. With the presented drive the speed sensors is not required. All the controls are based on measurement of the inverter output currents and dc input voltage. The proposed speed sensorless drive with the asynchronous motor was verified by the simulation and the experimental tests.

	Speed Anti-Windup PI strategies review for Field Oriented Control of Permanent Magnet Synchronous Machines Servo Drives with Matrix Converters By Jordi ESPINA, Antoni ARIAS, Carlos ORTEGA, Josep BALCELLS, Samuel GALCERAN	[View] [Download]
Abstract: When facing real systems PI tuning, the plant is modeled disregarding its physical limitations. Consequently, the PI output may increase indefinitely its value; phenomenon called Windup. This paper presents a review and a comparison between different Anti-Windup PI strategies used in speed motion and position control for Matrix Converter PMSM servo drives.

	Speed Control of Torsional Drive Systems with Backlash By Soenke THOMSEN, Friedrich W. FUCHS	[View] [Download]
Abstract: This paper presents the design, analysis and comparison of the conventional PI-control to two state space controllers for speed control of drive systems with elastically coupled loads. A state space controller of fourth order which considers only the mechanical system and a state space controller of fifth order which takes an approximation of the electrical system into account are analyzed. Thereby, the effects of backlash in the drive are analyzed in each control. State space control yields a high performance, is able to damp torsional oscillations effectively and to reduce backlash effects. Measurement results confirm these statements.

	Synchronous drives with field oriented vector control and their industrial implementation By Alexander WEINGER, Dmitry BELIAEV, Evgeny ILYIN, Arthur SHATOKHIN	[View] [Download]
Abstract: Field oriented control doesnâ€™t correspond to features of synchronous motor as good as it does to induction motor. Special control algorithm is proposed to provide operation, suitable for mass high-power drives. The solution is implemented and tested in two fan drives, 3.15 MW each, now in operation at a diamond mine in North-East Siberia.

	Voltage-Oriented Vector Control of Induction Motor: Principle and Dynamic Performance Improvement By Yongdong LI	[View] [Download]
Abstract: This paper deals with the performance improvement of the Voltage-Oriented Vector Control(VOC) of induction motor which presents the merits of constant stator flux control, simple calculation and easy implementation. In this method, the d-axis of synchronous reference frame is oriented in the direction of the stator voltage vector, and then a control strategy specific for the induction motor is obtained. Based on the previous work, much progress has been made recently to get better dynamic performance, including the improved system structure and a novel stator flux estimator. Simulation and experimental results show that by knowing only a few parameters of the induction motor such as Rs and J, the flux and torque can be controlled independently, and a simple as well as high-performance speed control can be achieved while avoiding the complex coordinate transformation in traditional vector control methods.

	Z-Source Drive Inverter using modified SVPWM for low Output Voltage and regenerating Operation By Moritz ZIMMERMANN, Martin LECHLER, Bernhard PIEPENBREIER	[View] [Download]
Abstract: Z-source inverters, consisting of both inductors and capacitors as DC-link components, provide unique boost capability with simple structure needing no additional switching elements. Due to complex operation modes of the Z-source inverter compared to a conventional inverter, boost operation, light load and regenerating operation cannot be achieved using common space-vector pulse width modulation. This paper proposes a modified SVPWM, derived from the known equations, to overcome this limitation. Besides, equations to control the output behaviour for all operating modes, such as buck, boost and regenerating operation, are given in detail. Finally, experimental results are presented.

	Zero Body Diode Conduction Time in Variable Speed Drive Converter Systems By Matthias ROSE, JÃ¶rg KRUPAR, Henry GÃœLDNER	[View] [Download]
Abstract: This paper describes a digital gate control approach for variable speed motor drive systems. The presented approach reduces body diode conduction time to zero without generation of cross conduction. The method uses a measurement impedance in series to the power devices of the converter system. This allows the direct detection of the current commutation interval and the load current direction in every half-bridge. With application of this approach we achieved an improved efficiency and electromagnetic behavior by the avoidance of body diode conduction and reverse recovery. The duration of a switching transition is minimized.