Dmj Holliday

Impact of Rotor Design on Sensorless Position Estimation

The impact of rotor design on the accuracy of a saliency based zero-speed sensorless position estimation technique is investigated. An existing prototype machine is used as the basis of the development and a number of possible buried magnet rotor designs are analysed before an optimal design is selected. It is shown that whilst it is possible to achieve the desired torque from a number of rotor variants, only a limited number of these are suitable for sensorless position estimation. Experimental results confirm the initial finite element based analyses

Sensorless Control of Permanent Magnet Machine Drives for Aerospace Applications

A real-time, sensorless, zero speed position sensing algorithm for permanent magnet machines is presented. The strategy is applicable to any brushless permanent magnet machine that exhibits magnetic saliency. It is computationally simple and fast and can be used with machines that exhibit distorted saliencies. A Finite Element model confirms the form of the magnetic saliency and provides a design tool enabling suitability for sensorless control to be included as a key consideration in the development of bespoke machines. This offers advantages in terms of improving the accuracy and robustness of any saliency based sensorless scheme. Finally, experimental results show that the position measurement scheme exhibits excellent agreement with results obtained using a resolver. The robustness of the technique makes it ideally suited to aerospace applications.

Zero Speed Sensorless Position Detection for Permanent Magnet Synchronous Machines

A real-time, sensorless, zero speed position sensing algorithm for permanent magnet synchronous machines is presented. The strategy is applicable to any brushless permanent magnet machine that exhibits magnetic saliency. It is computationally simple and fast and can be used with machines that exhibit distorted saliencies. Experimental results show that the position measurement scheme exhibits excellent agreement with results obtained using a resolver

Design Considerations for Permanent Magnet Brushless Machines for Zero-Speed Sensorless Position Estimation

This paper investigates the effect of stator slot shape on the accuracy of a saliency based zero-speed sensorless position estimation technique for brushless permanent magnet machines. Three machines with different rotor topologies are used as the basis of the finite element analysis and for each machine, experimental tests are carried out to verify the accuracy of the models. It is shown that the accuracy of the sensorless position estimation is significantly affected by the shape of the stator slots

A versatile zero-speed sensorless position detection technique for PMSMs

A versatile sensorless zero-speed position sensing algorithm for permanent magnet synchronous machines is presented. The strategy is applicable to any brushless permanent magnet machine that exhibits magnetic saliency. It is computationally simple and fast and can be used with machines that exhibit distorted saliencies. Experimental results show that the position measurement scheme can be used with different machine topologies and that it exhibits excellent agreement with results obtained using a resolver

IEEE Energy Conversion Congress & Exposition, Phoenix, AZ, USA

The useful bandwidth of power electronic switching waveform measurements is limited by the finite resolution of measurement instrumentation and the spectral characteristics of switching waveforms, which exhibit a steep roll-off with increasing frequency. This limits the use of such measurements in EMI generation analysis, simulation and prediction. A method combining PC-based offline data processing and high-pass filtering of the waveforms prior to measurement allows the useful measurement bandwidth to be extended to 100 MHz in the case of a 1200 V, 15 A IGBT operating under realistic conditions. When utilised with commercially available current probes and passive voltage probes, this method offers high-fidelity measurements. However, it is more difficult to obtain repeatable measurements with high-voltage differential probes. The resulting spectra of IGBT collector-emitter voltage and collector current waveforms are presented; the increased bandwidth allows the high-frequency spectral gradient of −60 dB/decade to be observed across the 30–100 MHz band most critical for radiated EMI generation in IGBT-based power converters. The effect of series gate resistance variation is thus apparent, and spectral evidence is provided for the 30–100 MHz band being dominated by the turn-on transients with small gate resistances, and by the turn-off transients with large gate resistances.

High-Bandwidth, High-Fidelity In-Circuit Measurement of Power Electronic Switching Waveforms for EMI Generation Analysis

The useful bandwidth of power electronic switching waveform measurements is limited by the finite resolution of measurement instrumentation and the spectral characteristics of switching waveforms, which exhibit a steep roll-off with increasing frequency. This limits the use of such measurements in EMI generation analysis, simulation and prediction. A method combining PC-based offline data processing and high-pass filtering of the waveforms prior to measurement allows the useful measurement bandwidth to be extended to 100 MHz in the case of a 1200 V, 15 A IGBT operating under realistic conditions. When utilised with commercially available current probes and passive voltage probes, this method offers high-fidelity measurements. However, it is more difficult to obtain repeatable measurements with high-voltage differential probes. The resulting spectra of IGBT collector-emitter voltage and collector current waveforms are presented; the increased bandwidth allows the high-frequency spectral gradient of −60 dB/decade to be observed across the 30–100 MHz band most critical for radiated EMI generation in IGBT-based power converters. The effect of series gate resistance variation is thus apparent, and spectral evidence is provided for the 30–100 MHz band being dominated by the turn-on transients with small gate resistances, and by the turn-off transients with large gate resistances.

A Comparison of a Flux Observer with a Back-Emf Technique for Sensorless Rotor Position Estimation

The performances of sensorless flux observer and back-EMF methods of rotor position estimation in a brushless permanent magnet generator are compared. A simulation model is developed to investigate the accuracy of each method in the presence of electrical distortion and noise. Experimental results show that, over a speed range of 50 -500 rpm, the flux observer is significantly more accurate than the back-EMF method