EPE Association: EPE 2011 - LS1g: Topic 12: Advanced Control Techniques

EPE 2011 - LS1g: Topic 12: Advanced Control Techniques
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2011 ECCE Europe - Conference > EPE 2011 - Topic 12: High performance drives > EPE 2011 - LS1g: Topic 12: Advanced Control Techniques

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   Direct Torque Control and Virtual-Flux Based Direct Power Control of Current Source Converter in Wind Turbine Application
By Aleksandar NIKOLIC, Borislav JEFTENIC [View]
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Abstract: Proposed control algorithm for current source converter (CSC) in wind turbine application is based on direct torque control (DTC) of permanent magnet synchronous generator and a virtual-flux based direct power control (VF-DPC) for grid side converter. State of novelty of the control algorithm rely on the fact that DTC and VF-DPC are not yet implemented in CSC applications. Furthermore, in proposed solution only sensors in DC link are required, since machine and grid side currents and voltages are reconstructed from DC link measurements and current state of active switches in rectifier and inverter, respectively. DTC for generator side converter is based on constant switching strategy developed for CSI induction motor drive. Instead of hysteresis torque and flux controllers it calculates stator flux reference from d and q reference currents and uses PI controller to determine reference DC link current. Modified switching table assures that switches are activated properly to generate lower torque ripples. On the grid side, DPC algorithm is used for control, assuming that transformer and line inductances are replaced with as a virtual AC motor model. Integration of phase-to-phase voltages of virtual motor yields virtual flux vector, necessary for estimating grid active and reactive power. Similarly to the basic DTC, VF-DPC uses hysteresis comparators to determine switching states in inverter. As a final result, proposed control algorithm assures independent active and reactive power control while maintaining the maximum converter efficiency and extracting the maximum power necessary for windgenerator systems. Simulation results confirm proposed control strategy.

   Flux-Weakening in IPM Motor Drives: Comparison of State-of-Art Algorithms and a Novel Proposal for Controller Design
By Silverio BOLOGNANI, Sandro CALLIGARO, Roberto PETRELLA, Filippo POGNI [View]
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Abstract: A review and comparison of some state-of-the-art flux-weakening algorithms for Interior Permanent Magnet Synchronous Motor (IPMSM) is presented in this paper, having voltage exploitation, dynamical performances and implementation efforts as key parameters of the comparison. Moreover an original proposal for the theoretical analysis of the overall dynamics of the voltage control loop is carried out, also taking into account non-linear effects and discrete-time implementation issues.All the considered algorithms have at least one feed-back path, thus providing steady-state voltage control even in presence of parameter errors, but different strategies are adopted leading to completely different behavioral characteristics. The approaches that will be analyzed are based on the control of the synchronous reference frame currents, the torque-flux characteristics and the voltage space vector angle.The effort for improving the voltage limitation performances, aiming at increasing dc bus voltage exploitation while still maintaining reasonable dynamical performances, is gaining importance due to both the efficiency demand (i.e. reducing the phase current magnitude for the required power) and some specific application issues, like the need for widening the speed-torque range given a relatively low voltage bus (e.g. in electrical or hybrid traction applications). A motor drive system for home appliances is considered in this paper as test bench for comparing the reviewed techniques. Simulation and experimental results are included.

   Saturation induced harmonics in permanent magnet synchronous motors
By Thomas ORLIK, Michael LUX, Walter SCHUMACHER [View]
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Abstract: This contribution presents an extended analytical model of permanent magnet synchronous motors that covers magnetic saturation effects for the fundamental wave and harmonic behaviour. Based on the extended motor equations a compensation scheme for saturation induced current harmonics is introduced, which is based on a precontrol of the induced stator voltages.

EPE 2011 - LS1g: Topic 12: Advanced Control Techniques
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2011 ECCE Europe - Conference > EPE 2011 - Topic 12: High performance drives > EPE 2011 - LS1g: Topic 12: Advanced Control Techniques
	[return to parent folder]

	Direct Torque Control and Virtual-Flux Based Direct Power Control of Current Source Converter in Wind Turbine Application By Aleksandar NIKOLIC, Borislav JEFTENIC	[View] [Download]
Abstract: Proposed control algorithm for current source converter (CSC) in wind turbine application is based on direct torque control (DTC) of permanent magnet synchronous generator and a virtual-flux based direct power control (VF-DPC) for grid side converter. State of novelty of the control algorithm rely on the fact that DTC and VF-DPC are not yet implemented in CSC applications. Furthermore, in proposed solution only sensors in DC link are required, since machine and grid side currents and voltages are reconstructed from DC link measurements and current state of active switches in rectifier and inverter, respectively. DTC for generator side converter is based on constant switching strategy developed for CSI induction motor drive. Instead of hysteresis torque and flux controllers it calculates stator flux reference from d and q reference currents and uses PI controller to determine reference DC link current. Modified switching table assures that switches are activated properly to generate lower torque ripples. On the grid side, DPC algorithm is used for control, assuming that transformer and line inductances are replaced with as a virtual AC motor model. Integration of phase-to-phase voltages of virtual motor yields virtual flux vector, necessary for estimating grid active and reactive power. Similarly to the basic DTC, VF-DPC uses hysteresis comparators to determine switching states in inverter. As a final result, proposed control algorithm assures independent active and reactive power control while maintaining the maximum converter efficiency and extracting the maximum power necessary for windgenerator systems. Simulation results confirm proposed control strategy.

	Flux-Weakening in IPM Motor Drives: Comparison of State-of-Art Algorithms and a Novel Proposal for Controller Design By Silverio BOLOGNANI, Sandro CALLIGARO, Roberto PETRELLA, Filippo POGNI	[View] [Download]
Abstract: A review and comparison of some state-of-the-art flux-weakening algorithms for Interior Permanent Magnet Synchronous Motor (IPMSM) is presented in this paper, having voltage exploitation, dynamical performances and implementation efforts as key parameters of the comparison. Moreover an original proposal for the theoretical analysis of the overall dynamics of the voltage control loop is carried out, also taking into account non-linear effects and discrete-time implementation issues.All the considered algorithms have at least one feed-back path, thus providing steady-state voltage control even in presence of parameter errors, but different strategies are adopted leading to completely different behavioral characteristics. The approaches that will be analyzed are based on the control of the synchronous reference frame currents, the torque-flux characteristics and the voltage space vector angle.The effort for improving the voltage limitation performances, aiming at increasing dc bus voltage exploitation while still maintaining reasonable dynamical performances, is gaining importance due to both the efficiency demand (i.e. reducing the phase current magnitude for the required power) and some specific application issues, like the need for widening the speed-torque range given a relatively low voltage bus (e.g. in electrical or hybrid traction applications). A motor drive system for home appliances is considered in this paper as test bench for comparing the reviewed techniques. Simulation and experimental results are included.

	Saturation induced harmonics in permanent magnet synchronous motors By Thomas ORLIK, Michael LUX, Walter SCHUMACHER	[View] [Download]
Abstract: This contribution presents an extended analytical model of permanent magnet synchronous motors that covers magnetic saturation effects for the fundamental wave and harmonic behaviour. Based on the extended motor equations a compensation scheme for saturation induced current harmonics is introduced, which is based on a precontrol of the induced stator voltages.