Fault signal propagation through the PMSM motor drive systems

This paper describes how a mechanical disturbance on the shaft of a variable speed permanent magnet motor (PMSM) is propagated to the supply input side of the drive system, and therefore may be detected by monitoring specific frequency components in the rectifier input current. The propagation of the disturbance from the torque disturbance, to the motor current, then to the dc link current and finally to the rectifier input current is derived as a series of transfer functions so that both the frequency and the amplitude of the disturbance component in the rectifier input current can be predicted for a specific mechanical disturbance. The limitations to detect the mechanical fault by monitoring only the supply currents are also addressed. Simulation and experimental results are presented to demonstrate the accuracy of the quantitative analysis, and the potential for fault detection using the rectifier input currents

Serangga dan mitos suku kaum jakun, Kampung Peta, Mersing Johor

This study focuses on seeing insects from the mythical perspective of the Orang Asli tribe of Jakun, Kampung Peta, Mersing Johor. The existence of insects in the life of every ethnic in Malaysia has brought various elements of myths. Therefore, when combining myths and insects, it could be said that myth is a human way of understanding, expressing and linking insects to him/herself as well as a group/culture. The practice of using insects among ethnic groups in daily life is called etnoentomology. In this study, the insects studied are the butterfly (Lepidoptera), the odonates (Odonata) and the cicadas (Homoptera). This is because these insects are very popular in the community and have their own myths that are brought into the local culture of belief

Inverter Design for SiC-based Electric Drive Systems with Optimal Redundant States Control of Space Vector Modulation

The need for inverters with ever increasing power density and efficiency has recently become the driving factor for research in various fields. Increasing the operating voltage of the whole drive system and utilizing newly developed SiC power switches can contribute towards this goal. Higher operating voltage allows the design of drives with lower current, which leads to lower copper losses in cables and machine, while SiC switches can drastically increase the inverter efficiency. Offshore renewable power generation, such as tidal power, is a typical application where the increase of operating voltage can be highly beneficial. The ongoing electrification of transportation calls also for high power electric powertrains with high power density,where SiC technology has key advantages.In the first part of the thesis, suitable control schemes for inverters in synchronous machine drive systems are derived. A properly designed Maximum Power Point Tracking algorithm for kite-based tidal power systems is presented. The speed and torque of this new tidal power generation system varies periodically and the inverter control needs to be able to handle this variable power profile. Experimental verification of the developed control is conducted on a 35 kVA laboratory emulator of the tidal power generation unit.Electric drives using multilevel inverters are studied afterwards. Multilevel inverters use multiple low-voltage-rated switches and can operate at higher voltage than standard two-level inverters. The Neutral Point Clamped (NPC) converter is a commonly used multilevel inverter topology for medium voltage machine drives. However, the voltage balancing of its dc-side capacitors and the complexity of its control are still issues that have not been effectively solved. A new method for the optimal utilization of the redundant states in Space Vector pulse-width-Modulation (SVM) is proposed in this thesis in order to control its dc-link voltages. Experimental verification on a 4-kV-rated prototype medium-voltage PMSM drive with 5-level NPC converters is conducted in order to validate the effectiveness of the proposed control technique.Low switching and conduction losses are typical characteristics of SiC switches that can be utilized to build inverters with high power density, due to the increased efficiency and smaller form-factor. Due to the above, SiC power modules have been particularly attractive for the automotive industry. The design approach of 2-level automotive inverters has been studied in this project. Moreover, a new design approach for the cooling system of automotive inverters has been developed in this thesis, which fine-tunes the inverter heatsink utilizing standard legislated test routines for electric vehicles. Multiple conjugate-heat-transfer (CHT) computation results showcase the iterative optimization procedure on a test-case 250 kW (450 A) automotive SiC inverter.Finally, the experimental testing of high power machine drives in order to verify the control and the hardware design is an important step of the development process. Thus, the performance of the prototype 450 A SiC 2-level inverter has been been experimentally validated in a power hardware-in-the-loop (P-HIL) set-up that emulates an automotive drive system. Several challenges have been addressed with respect to the accurate modelling of the motor and the control of the circulating power in the system. A new control technique utilizing the redundant states of the SVM has been developed for this set-up to effectively suppress the zero-sequence current to 3.3 % of the line current at rated power

Systems, Methods and Devices for Vector Control of Permanent Magnet Synchronous Machines using Artificial Neural Networks

An example method for controlling an AC electrical machine can include providing a PWM converter operably connected between an electrical power source and the AC electrical machine and providing a neural network vector control system operably connected to the PWM converter. The control system can include a current-loop neural network configured to receive a plurality of inputs. The current-loop neural network can be configured to optimize the compensating dq-control voltage. The inputs can be d- and q-axis currents, d- and q-axis error signals, predicted d- and q-axis current signals, and a feedback compensating dq-control voltage. The d- and q-axis error signals can be a difference between the d- and q-axis currents and reference d- and q-axis currents, respectively. The method can further include outputting a compensating dq-control voltage from the current-loop neural network and controlling the PWM converter using the compensating dq-control voltage

Analysis of vertical strip wound fault-tolerant permanent magnet synchronous machines

This paper investigates the behavior of a vector- controlled, fault-tolerant, permanent magnet motor drive system adopting a vertically placed strip winding (VSW) which can limit inter-turn short-circuit (SC) fault current to its rated value regardless of the position in the slot containing the shorted turns. The drives’ dynamic behavior is simulated using a per-phase equivalent circuit model with the winding inductances and resistances analytical calculated based on the machine geometry and fault location. A simplified thermal model is also grafted into the system model to effectively simulate the dynamic behavior of the machine during healthy, inter-turn SC fault and post-fault controlled scenarios. The SC fault current limiting capability, the additional losses and thermal behavior of the winding are studied and compared with conventional winding adopting round conductors winding (RCW). The proposed winding design is verified with Finite Element (FE) analysis and then validated experimentally. Results show that the VSW inherently limits the SC current, reduces its dependence on the position of the fault within the slot but results in an increase in AC losses

Torque Control

This book is the result of inspirations and contributions from many researchers, a collection of 9 works, which are, in majority, focalised around the Direct Torque Control and may be comprised of three sections: different techniques for the control of asynchronous motors and double feed or double star induction machines, oriented approach of recent developments relating to the control of the Permanent Magnet Synchronous Motors, and special controller design and torque control of switched reluctance machine

Advances in the Field of Electrical Machines and Drives

Electrical machines and drives dominate our everyday lives. This is due to their numerous applications in industry, power production, home appliances, and transportation systems such as electric and hybrid electric vehicles, ships, and aircrafts. Their development follows rapid advances in science, engineering, and technology. Researchers around the world are extensively investigating electrical machines and drives because of their reliability, efficiency, performance, and fault-tolerant structure. In particular, there is a focus on the importance of utilizing these new trends in technology for energy saving and reducing greenhouse gas emissions. This Special Issue will provide the platform for researchers to present their recent work on advances in the field of electrical machines and drives, including special machines and their applications; new materials, including the insulation of electrical machines; new trends in diagnostics and condition monitoring; power electronics, control schemes, and algorithms for electrical drives; new topologies; and innovative applications

Electric Vehicle Powertrain Integrated Charging

Batterieelektrische Fahrzeuge benötigen ein im Fahrzeug eingebautes Ladegerät, um die Energie aus dem Wechselstromnetz für die Gleichstrom- Batterie aufzubereiten. Integriertes Laden ist eine Methode der Integration von Ladefunktionalität in die Antriebsstrangkomponenten, welche während des Parkens außer Betrieb sind, mit dem Ziel, Kosten, Gewicht und Volumen des Ladegerät zu sparen. Das Laden ohne die Sicherheitsmaßnahme einer galvanischen Trennung im Ladegerät ist möglich mit zusätzlichen Maßnahmen gegen elektrischen Schlag, z.B. mit einer Fehlerstromerkennung und entsprechenden Trenneinrichtung. Im Stand der Technik wurden 33 integrierte Ladekonzepte gefunden und bezüglich Antriebsstrangnutzung, benötigte Komponenten, Drehmoment der elektrischen Maschine und Wirkungsgrad verglichen. Im Rahmen dieser Arbeit wird ein neues galvanisch getrenntes integriertes Ladekonzept beschrieben, mit dem Ziel, die Effizienz zu verbessern und gleichzeitig auftretendes Drehmoment in der Maschine zu vermeiden. Der Antriebsstrang wird als DC/DC-Wandler mit der elektrischen Maschine als Transformator im Stillstand genutzt. Berechnungen zeigen eine maximale Effizienz von 88%. Ansätze zur Verbesserung des Wirkungsgrads und zur Integration des Energieflusses im Bordnetz werden in dieser Arbeit vorgeschlagen und diskutiert. Allerdings muss der Rotorkäfig geöffnet werden, um ein Drehmoment während des Laden zu vermeiden. Dies stellt einen ähnlichen Aufwand dar wie die Darstellung eines separaten Ladegeräts. Somit ist dieses Konzept aus heutiger Sicht wegen niedriger Effizienz und hoher Kosten gegenüber einem separaten Ladegerät nicht konkurrenzfähig. Zwei Ladekonzepte ohne galvanische Trennung, die eine sechsphasige elektrische Maschine als in Serie geschaltete Hoch- und Tiefsetzsteller nutzen, werden im Rahmen der Arbeit vorgestellt und bezüglich der benötigten Komponenten, der Effizienz und des Drehmoments des Maschine ausgearbeitet. Die Antriebsstrangverluste werden für die Ladebedingungen mit Gleichströmen analysiert, basierend auf neuen Materialcharakterisierungen für die angewendete Belastung. Es wurden Wirkungsgrade bis zu 93% demonstriert und auch in theoretischen Berechnungen mit einer maximalen Abweichung von ±1% zum experimentellen Befund bestätigt. Zum Schutz gegen elektrischen Schlag bei nicht isolierten Ladekonzepten werden drei Konzepte für eine Fehlerstrommessung präsentiert und anhand von Messergebnissen analysiert. Siliziumkarbid-Inverter-Technologien zeigen in Kombination mit diesen Ladekonzepten Wirkungsgrade, die vergleichbar zu herkömmlichen separaten Ladegeräten sind, und weisen dabei deutlich geringere Kosten auf