David Reigosa

Carrier-Signal Selection for Sensorless Control of PM Synchronous Machines at Zero and Very Low Speeds

This paper compares pulsating- and rotating-vector carrier-signal injection for self-sensing (or sensorless) control of permanent-magnet synchronous machines (PMSMs). The main focus of this paper is the evaluation of estimation errors due to the physical nonideal attributes of both the machine and the inverter. Initial-position and magnet-polarity estimations are analyzed as well. Transient response and signal processing for both techniques are discussed for completeness. The theoretical analysis is supported by experimental and simulation evidence obtained using interior PMSMs.

Measurement and Adaptive Decoupling of Cross-Saturation Effects and Secondary Saliencies in Sensorless-Controlled IPM Synchronous Machines

This paper analyzes effects of magnetic saturation, including cross-saturation and secondary saliencies, on saliency- based sensorless control of interior PM synchronous machines. These effects are mitigated by adaptively decoupling saturation induced-saliencies via a structured neural network. The paper includes identification of the dominant, saturation-induced components of the carrier signal current interfering with the rotor position-dependent component being tracked, characterization of these components, and implementation of a non-linear, adaptive, saturation-induced components structured neural network model to perform their decoupling.

Carrier Signal Selection for Sensorless Control of PM Synchronous Machines at Zero and Very Low Speeds

This paper compares pulsating and rotating vector carrier signal injection for self-sensing (or sensorless) control of PM synchronous machines. The main focus of the study is evaluation of estimation errors due to the physical non-ideal attributes of both the machine and the inverter. Initial position and magnet polarity estimation are analyzed as well. Transient response and signal processing for both techniques is discussed for completeness. The theoretical analysis is supported by experimental and simulation evidence obtained using interior PM synchronous machines.

A comparative analysis of pulsating vs. rotating vector carrier signal injection-based sensorless control

This paper analyzes the sensitivity to non-ideal physical attributes of pulsating and rotating vector carrier-injection based sensorless techniques, as well as of the impact on the accuracy and robustness of the sensorless control. The analysis is mainly done on the basis of terminal attributes of machines. Initial observations on the subsequent finite element study are also given. Commonly used filtering and position estimation techniques associated with each carrier signal are considered. The analysis is supported by experimental evidence obtained using interior PM synchronous machines, but the findings are applicable to other AC machines as well.

Modeling and Adaptive Decoupling of High-Frequency Resistance and Temperature Effects in Carrier-Based Sensorless Control of PM Synchronous Machines

This paper analyzes the effects of the high-frequency resistances in saliency tracking-based sensorless control methods of permanent-magnet synchronous machines (PMSMs). A high-frequency model of the PMSM, including stator high-frequency resistance, is presented. From this model, potential sources of error in the estimated position due to the high-frequency resistances are analyzed, and their compensation by means of an adaptive decoupling mechanism is proposed. This paper also addresses the influence and compensation of temperature effects in carrier-signal-injection-based sensorless techniques.

Magnet Temperature Estimation in Surface PM Machines Using High-Frequency Signal Injection

This paper proposes a method to estimate the magnet temperature in surface permanent-magnet machines using high-frequency carrier signal injection. The injection of a high-frequency signal, superimposed on the fundamental excitation, allows the estimation of the stator high-frequency impedance, which is a function of both the stator and rotor impedances. The temperature of the magnets is shown to have a significant weight on the overall stator high-frequency impedance, from which it can be estimated. The high-frequency carrier signal is injected intermittently in order to minimize potential adverse effects on the normal operation of the machine. This paper first explains the physics behind the magnet temperature dependence. Then, the principles of the method, as well as its practical implementation, are discussed. Experimental verification of the method is provided.

Active Islanding Detection Using High-Frequency Signal Injection

Islanding detection is of great importance for reliable operation of smart grids. Islanding detection methods can be classified into three different groups: active, passive and communication based methods. Active methods inject a disturbing signal (typically a voltage) and analyze the system response (typically in the current). These techniques have a low non-detection zone but present the inconvenience inherent to injecting a disturbing signal. Passive methods monitor the grid condition from the grid variables. These techniques are easy to implement, but present a large non-detection zone. Communications methods have the inconvenient of relying on communications, currently being of limited use. This paper proposes a new active islanding detection method, based on measurement of the grid high frequency impedance by means of the injection of a high frequency voltage. Advantages of the method are almost negligible adverse effects due to the injected high frequency voltage and accurate and fast islanding detection -in the rage of few ms-. Furthermore, the estimated high frequency impedance can be used for adaptive control of the power converter.1

Modeling and Adaptive Decoupling of Transient Resistance and Temperature Effects in Carrier-Based Sensorless Control of PM Synchronous Machines

This paper analyzes the effects of the transient resistances in saliency tracking-based sensorless control methods of PM synchronous machines. A high frequency model of the PM synchronous machine including both stator and rotor transient resistance is presented. From this model, potential sources of error in the estimated position due to the transient resistances are analyzed, and their compensation by means of an adaptive decoupling mechanism is proposed. The paper also addresses the influence and compensation of temperature effects in carrier signal injection-based sensorless techniques.

Active Islanding Detection for Multiple Parallel-Connected Inverter-Based Distributed Generators Using High-Frequency Signal Injection

This paper proposes a method for islanding detection in microgrids with multiple parallel-connected inverters using high-frequency signal injection. In the proposed method, a master inverter injects the high-frequency signal which is used by the rest of inverters for islanding detection, with two distinguishing features: 1) The slave inverters work in a high-frequency current cancellation mode, what prevents interference and 2) in case of master failure or significant changes in the grid, the remaining inverters will dynamically reassign roles, the new master inverter being self-selected, based on a deterministic performance criteria and without the need of communications.

Interior Permanent-Magnet Synchronous Motor Design for Improving Self-Sensing Performance at Very Low Speed

The focus of this paper is to improve the self-sensing performance of an interior permanent-magnet synchronous machine (IPMSM) by modifying the rotor configurations. A field-intensified IPMSM (FIIPMSM) is designed by adding flux barriers in the rotor of an IPMSM. In comparison with IPMSMs, FIIPMSMs have the advantage of decoupling saturation-induced saliency, cross-coupling effects, and also secondary saliencies, which reduce the estimation accuracy of self-sensing control for IPMSMs. A finite element analysis is used to design the FIIPMSM and assess the performance of the machine for self-sensing. The self-sensing capabilities of IPMSMs and FIIPMSMs are presented and compared. The results demonstrate the improved self-sensing performance of the new field-intensified machine.