EPE Association: EPE-PEMC 2002: Special Session: Non Model-Based Zero Speed Sensorless Control Techniques for AC Motor Drives

EPE-PEMC 2002: Special Session: Non Model-Based Zero Speed Sensorless Control Techniques for AC Motor Drives
You are here: EPE Documents > 04 - EPE-PEMC Conference Proceedings > EPE-PEMC 2002 - Conference > EPE-PEMC 2002: Special Session: Non Model-Based Zero Speed Sensorless Control Techniques for AC Motor Drives

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   A Study of Sensorless Control of Induction Motor at Zero Speed Utilizing High Frequency Voltage Injection
By T. A. Lipo; D. Zarko; D. Drevensek [View]
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Abstract: A detailed investigation of sensorless control of induction motor at zero and very low speed based on injection of a pulsating high frequency voltage signal is presented. A sensing technique used to measure air gap flux position in a squirrel cage induction motor is based on the secondary effect of magnetic spatial nonlinearity caused by saturation of the stator laminations. The physical insight into the motor excited by high frequency test signals is given by means of experiment and finite element simulation. It is shown that it is possible to control the motor torque using the proposed technique, but with low bandwidth and with the necessity to perform special tests and measure special characteristics for each new motor prior to utilization.

   An Alternative to High Frequency Current Detection Techniques for Zero Speed Sensorless Control of AC Motor Drives
By A. Consoli; A. Testa; G. Scarcella [View]
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Abstract: The paper presents the main features of the Zero Sequence Technique (ZST), a sensorless algorithm able to work at low and zero speed with full torque capability. The proposed method is different in principle than any other sensorless technique and much simpler on the implementation aspects, although it still belongs to the class of air gap flux estimators. A distinctive characteristic of the approach is that it also allows us to detect the amplitude of the air gap flux, thus exploiting full flux sensing capability not limited to only flux position estimation. Experimental and Finite Element Analysis results validate the performance of the method in comparison with standard sensorless techniques based on detecting the amplitude variation of high frequency currents.

   Sensorless Rotor Position Control in a Surface Mounted PM Machine Using HF Voltage Injection
By K. J. Bradley; M. Sumner; G. M. Asher; C. Silva [View]
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Abstract: This paper presents the use of HF voltage signal injection for tracking position in an off-the-shelf surface mounted permanent magnet machine. The inherent low saliency of this type of machines presents difficulties and makes the signal conditioning highly critical. In this paper the method of space-modulation profiling (SMP) is used to obtain a magnetic signature of the machine in order to correct for periodic errors in the position signals. Experimental results illustrate the effectiveness of this technique in providing position signals of high quality. These are then exploited to provide closed loop sensorless position control of good bandwidth.

   Slot Geometry an Important Design Parameter for Zero Speed Sensorless Control of Standard Induction Machines
By J. L. Machl; T. M. Wolbank; R. Woehrnschimmel [View]
[Download]

Abstract: To realise a high dynamic controlled operation of induction machines the flux position has to be estimated during normal operation of the drive. Omitting the shaft sensor leads to a deterioration of the performance at low fundamental frequencies if fundamental wave models of the machine are used. To determine the flux position at zero speed without shaft sensor it is thus necessary to use parasitic nonfundamental wave effects of standard induction machines, such as spatial saturation, slotting or magnetic anisotropy. These effects are not evident in normal operation but can be exploited using high frequencies. Sensorless zero speed schemes thus make use of a high frequency or transient excitation of the machine in addition to the fundamental wave, which are both impressed by the inverter. The machine reaction on this high frequency excitation is then measured and the flux and/or rotor position signal can be estimated by signal processing. However, the shape of the lamination and especially the slot geometry have strong influence on the high frequency behaviour. Before realising a sensorless controlled drive it is thus advantageous to have a look at the design of the machine as not any design is suitable for a specific sensorless control algorithm. Usually either the flux or the rotor position can be extracted by exploiting the two most prominent saliencies caused by saturation and slotting. To investigate the mentioned influence, measurements have been performed and compared on machines designed with different slot geometry. Based on these results, a deeper insight into the spatial distribution of the transient flux linkage and its influence on the control signals is given.

EPE-PEMC 2002: Special Session: Non Model-Based Zero Speed Sensorless Control Techniques for AC Motor Drives
You are here: EPE Documents > 04 - EPE-PEMC Conference Proceedings > EPE-PEMC 2002 - Conference > EPE-PEMC 2002: Special Session: Non Model-Based Zero Speed Sensorless Control Techniques for AC Motor Drives
	[return to parent folder]

	A Study of Sensorless Control of Induction Motor at Zero Speed Utilizing High Frequency Voltage Injection By T. A. Lipo; D. Zarko; D. Drevensek	[View] [Download]
Abstract: A detailed investigation of sensorless control of induction motor at zero and very low speed based on injection of a pulsating high frequency voltage signal is presented. A sensing technique used to measure air gap flux position in a squirrel cage induction motor is based on the secondary effect of magnetic spatial nonlinearity caused by saturation of the stator laminations. The physical insight into the motor excited by high frequency test signals is given by means of experiment and finite element simulation. It is shown that it is possible to control the motor torque using the proposed technique, but with low bandwidth and with the necessity to perform special tests and measure special characteristics for each new motor prior to utilization.

	An Alternative to High Frequency Current Detection Techniques for Zero Speed Sensorless Control of AC Motor Drives By A. Consoli; A. Testa; G. Scarcella	[View] [Download]
Abstract: The paper presents the main features of the Zero Sequence Technique (ZST), a sensorless algorithm able to work at low and zero speed with full torque capability. The proposed method is different in principle than any other sensorless technique and much simpler on the implementation aspects, although it still belongs to the class of air gap flux estimators. A distinctive characteristic of the approach is that it also allows us to detect the amplitude of the air gap flux, thus exploiting full flux sensing capability not limited to only flux position estimation. Experimental and Finite Element Analysis results validate the performance of the method in comparison with standard sensorless techniques based on detecting the amplitude variation of high frequency currents.

	Sensorless Rotor Position Control in a Surface Mounted PM Machine Using HF Voltage Injection By K. J. Bradley; M. Sumner; G. M. Asher; C. Silva	[View] [Download]
Abstract: This paper presents the use of HF voltage signal injection for tracking position in an off-the-shelf surface mounted permanent magnet machine. The inherent low saliency of this type of machines presents difficulties and makes the signal conditioning highly critical. In this paper the method of space-modulation profiling (SMP) is used to obtain a magnetic signature of the machine in order to correct for periodic errors in the position signals. Experimental results illustrate the effectiveness of this technique in providing position signals of high quality. These are then exploited to provide closed loop sensorless position control of good bandwidth.

	Slot Geometry an Important Design Parameter for Zero Speed Sensorless Control of Standard Induction Machines By J. L. Machl; T. M. Wolbank; R. Woehrnschimmel	[View] [Download]
Abstract: To realise a high dynamic controlled operation of induction machines the flux position has to be estimated during normal operation of the drive. Omitting the shaft sensor leads to a deterioration of the performance at low fundamental frequencies if fundamental wave models of the machine are used. To determine the flux position at zero speed without shaft sensor it is thus necessary to use parasitic nonfundamental wave effects of standard induction machines, such as spatial saturation, slotting or magnetic anisotropy. These effects are not evident in normal operation but can be exploited using high frequencies. Sensorless zero speed schemes thus make use of a high frequency or transient excitation of the machine in addition to the fundamental wave, which are both impressed by the inverter. The machine reaction on this high frequency excitation is then measured and the flux and/or rotor position signal can be estimated by signal processing. However, the shape of the lamination and especially the slot geometry have strong influence on the high frequency behaviour. Before realising a sensorless controlled drive it is thus advantageous to have a look at the design of the machine as not any design is suitable for a specific sensorless control algorithm. Usually either the flux or the rotor position can be extracted by exploiting the two most prominent saliencies caused by saturation and slotting. To investigate the mentioned influence, measurements have been performed and compared on machines designed with different slot geometry. Based on these results, a deeper insight into the spatial distribution of the transient flux linkage and its influence on the control signals is given.