EPE Association: EPE 2005 - Topic 11-2 - LS: Sensorless Control of permanent magnet synchronous motor drives

EPE 2005 - Topic 11-2 - LS: Sensorless Control of permanent magnet synchronous motor drives
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2005 - Conference > EPE 2005 - Topic 11: HIGH PERFORMANCE DRIVES > EPE 2005 - Topic 11-2 - LS: Sensorless Control of permanent magnet synchronous motor drives

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   A Simulation Method for Analyzing Saliencies with Respect to Enhanced INFORM-Capability for Sensorless Control of PM Motors in the Low Speed Range including Sta
By RIEDER Ul; SCHROEDL Manfred [View]
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Abstract: In many drive applications, the so called “sensorless” control of Permanent Magnet Synchronous Machines (PMSM) has got increasing importance with respect to reduced costs and increased reliability. The position estimation based on back-EMF in the high speed range is already state of the art. In the low speed range there are different approaches for measuring and evaluating inherent saliencies, caused by saturation due to permanent magnets, stator current and rotor geometry. A type test of the PMSM is necessary for specifying the capability of sensorless angular position detection and control at low speed and standstill. However, a prediction based on simulation would support the construction process of the PMSM considerably. Hence, in this paper, a simulation method that yields information about the “INFORM-capability” of the PMSM is introduced. The correspondence between the simulation strategy and the sensorless measurement sequence will be explained in detail. The result is a simulation method, that yields an a priori information about the ability for sensorless control in the low speed range and thus is a useful tool for PMSMs that are still under construction and shall be used in sensorless applications. The method is verified on an External Rotor PMSM with surface-mounted magnets.

   Impacts of Cross-Saturation on Sensorless Control of Surface Permanent Magnet Synchronous Motors
By FRENZKE Thorsten [View]
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Abstract: Cross-magnetisation complicates the sensorless control of non-salient ac machines, like surface magnet synchronous motors. The motor currents influence position estimation techniques for low speed based on "saturation induced" saliencies. This paper considers cross-saturation effects to explain the magnetic-axis shift under loaded conditions and discusses the influence of the operating point on the saliency. A finite element analysis and lab measurements validate the results.

   Implementation Issues for Fast Initial Position and Magnet Polarity Identification of PM Synchronous Machines With Nearly Zero Saliency Ratio
By LORENZ Robert; HARKE Michael; RACA Dejan [View]
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Abstract: This paper presents a significant discussion of implementation details of an enhanced fast initial position and magnet polarity estimation method for low saliency PM synchronous machines. The carrier frequency operating-point model of the machine has been extended to include the effect of cross-saturation as part of the non-linear interactions of the machine inductance to an applied rotating voltage vector. The resulting carrier signal current components are isolated using synchronous reference frame filtering and the initial position and magnet polarity is estimated using a dual-vector tracking state filter. The paper also provides an extended discussion of design tradeoffs in tuning of the synchronous reference frame filters in conjunction with the dual-vector tracking state filter bandwidth. Experimental results demonstrate fast, reliable initial position and magnet polarity estimation with improved accuracy and speed of convergence.

   Using Optimized Transient Excitation Technique to Stabilize Model-Based Sensorless Control of Induction Machine
By MACHL JueRgen L.; GIULIANI Harald; WOLBANK Thomas [View]
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Abstract: High dynamic control if induction machine is only achievable by some sort of field oriented control.Realizing this type of control without using a shaft sensor has the advantage of increased reliability and decreased costs. Although used in the higher frequency range, methods considering only fundamental wave quantities of the machine will deteriorate in their performance at low or zero stator frequency due to the lack of signal and an increasing influence of noise and parameter uncertainties.The only way to establish a stable and controlled operation at and around zero stator frequency so far is to utilize non-fundamental effects of the machine. These effects can be exploited by determining the high frequency or transient electrical parameters of the machine. Parasitic effects like spatial saturation, slotting, or anisotropy of the rotor influence these transient electrical parameters. Any movement of one of these saliencies thus leads to a modulation of the signal obtained enabling thus the detection of the flux and/or rotor position. These estimated saliency position signals can be noisy what may cause problems in the control loop. Using conventional filtering methods leads to a reduction of the dynamic control performance. In this paper an excitation of the machine with voltage pulses is applied and methods to reduce disturbing harmonics in the control signals as well as ways to realize effective filtering are described.The reduction of disturbing harmonics is based on a compensation of non-ideal inverter/sensor properties and can be realized by optimization of the excitation pulses and/or placing of the sample instants. The effective filtering without loosing dynamic performance is based on a combination of the transient excitation method and a fundamental wave model of the machine. The signal obtained from the transient excitation is used to stabilize the model what results in a smoothed output much more suitable for the machine control. The advantage of this structure is, that the dynamic performance is not reduced, as is the case with conventional filtering methods.

EPE 2005 - Topic 11-2 - LS: Sensorless Control of permanent magnet synchronous motor drives
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2005 - Conference > EPE 2005 - Topic 11: HIGH PERFORMANCE DRIVES > EPE 2005 - Topic 11-2 - LS: Sensorless Control of permanent magnet synchronous motor drives
	[return to parent folder]

	A Simulation Method for Analyzing Saliencies with Respect to Enhanced INFORM-Capability for Sensorless Control of PM Motors in the Low Speed Range including Sta By RIEDER Ul; SCHROEDL Manfred	[View] [Download]
Abstract: In many drive applications, the so called “sensorless” control of Permanent Magnet Synchronous Machines (PMSM) has got increasing importance with respect to reduced costs and increased reliability. The position estimation based on back-EMF in the high speed range is already state of the art. In the low speed range there are different approaches for measuring and evaluating inherent saliencies, caused by saturation due to permanent magnets, stator current and rotor geometry. A type test of the PMSM is necessary for specifying the capability of sensorless angular position detection and control at low speed and standstill. However, a prediction based on simulation would support the construction process of the PMSM considerably. Hence, in this paper, a simulation method that yields information about the “INFORM-capability” of the PMSM is introduced. The correspondence between the simulation strategy and the sensorless measurement sequence will be explained in detail. The result is a simulation method, that yields an a priori information about the ability for sensorless control in the low speed range and thus is a useful tool for PMSMs that are still under construction and shall be used in sensorless applications. The method is verified on an External Rotor PMSM with surface-mounted magnets.

	Impacts of Cross-Saturation on Sensorless Control of Surface Permanent Magnet Synchronous Motors By FRENZKE Thorsten	[View] [Download]
Abstract: Cross-magnetisation complicates the sensorless control of non-salient ac machines, like surface magnet synchronous motors. The motor currents influence position estimation techniques for low speed based on "saturation induced" saliencies. This paper considers cross-saturation effects to explain the magnetic-axis shift under loaded conditions and discusses the influence of the operating point on the saliency. A finite element analysis and lab measurements validate the results.

	Implementation Issues for Fast Initial Position and Magnet Polarity Identification of PM Synchronous Machines With Nearly Zero Saliency Ratio By LORENZ Robert; HARKE Michael; RACA Dejan	[View] [Download]
Abstract: This paper presents a significant discussion of implementation details of an enhanced fast initial position and magnet polarity estimation method for low saliency PM synchronous machines. The carrier frequency operating-point model of the machine has been extended to include the effect of cross-saturation as part of the non-linear interactions of the machine inductance to an applied rotating voltage vector. The resulting carrier signal current components are isolated using synchronous reference frame filtering and the initial position and magnet polarity is estimated using a dual-vector tracking state filter. The paper also provides an extended discussion of design tradeoffs in tuning of the synchronous reference frame filters in conjunction with the dual-vector tracking state filter bandwidth. Experimental results demonstrate fast, reliable initial position and magnet polarity estimation with improved accuracy and speed of convergence.

	Using Optimized Transient Excitation Technique to Stabilize Model-Based Sensorless Control of Induction Machine By MACHL JueRgen L.; GIULIANI Harald; WOLBANK Thomas	[View] [Download]
Abstract: High dynamic control if induction machine is only achievable by some sort of field oriented control.Realizing this type of control without using a shaft sensor has the advantage of increased reliability and decreased costs. Although used in the higher frequency range, methods considering only fundamental wave quantities of the machine will deteriorate in their performance at low or zero stator frequency due to the lack of signal and an increasing influence of noise and parameter uncertainties.The only way to establish a stable and controlled operation at and around zero stator frequency so far is to utilize non-fundamental effects of the machine. These effects can be exploited by determining the high frequency or transient electrical parameters of the machine. Parasitic effects like spatial saturation, slotting, or anisotropy of the rotor influence these transient electrical parameters. Any movement of one of these saliencies thus leads to a modulation of the signal obtained enabling thus the detection of the flux and/or rotor position. These estimated saliency position signals can be noisy what may cause problems in the control loop. Using conventional filtering methods leads to a reduction of the dynamic control performance. In this paper an excitation of the machine with voltage pulses is applied and methods to reduce disturbing harmonics in the control signals as well as ways to realize effective filtering are described.The reduction of disturbing harmonics is based on a compensation of non-ideal inverter/sensor properties and can be realized by optimization of the excitation pulses and/or placing of the sample instants. The effective filtering without loosing dynamic performance is based on a combination of the transient excitation method and a fundamental wave model of the machine. The signal obtained from the transient excitation is used to stabilize the model what results in a smoothed output much more suitable for the machine control. The advantage of this structure is, that the dynamic performance is not reduced, as is the case with conventional filtering methods.