Dynamic output feedback linearizing control of saturated induction motors with torque per ampere ratio maximization

The paper presents a novel maximum torque per Ampere (MTA) controller for induction motor (IM) drives. The proposed controller exploits the concept of direct (observer based) field orientation and guarantees asymptotic torque tracking of smooth reference trajectories and maximizes the torque per Ampere ratio when the developed torque is constant or slowly varying. A dynamic output-feedback linearizing technique is employed for the torque subsystem design. In order to improve torque tracking accuracy a motor magnetizing curve is taken into account during MTA optimization and controller design. The achieved steady-state system efficiency have been compared experimentally for three types of controllers, namely: standard vector control with constant flux operation, controller based on classic maximization of torque per Ampere ratio for linear magnetic circuit and controller based on MTA strategy for saturated induction motor. It is shown experimentally that the controller designed for saturated induction motor provides not only higher torque per Ampere ratio but also increases power factor and reduces active power consumption hence improving the drive efficiency. Operation with slowly varying torque references has also been analysed. It is shown that the proposed controller is suitable for applications that do not demand an extremely fast dynamic response, for example for electric vehicle drives

Maximum torque-per-Amp control for traction IM drives: theory and experimental results

A novel maximum torque per Ampere (MTPA) controller for induction motor (IM) drives is presented. It is shown to be highly suited to applications that do not demand an extremely fast dynamic response, for example electric vehicle drives. The proposed MTPA field oriented controller guarantees asymptotic torque (speed) tracking of smooth reference trajectories and maximises the torque per Ampere ratio when the developed torque is constant or slow varying. An output-feedback linearizing concept is employed for the design of torque and flux subsystems to compensate for the torque-dependent flux variations required to satisfy the MTPA condition. As a first step, a linear approximation of the IM magnetic system is considered. Then, based on a standard saturated IM model, the nonlinear static MTPA relationships for the rotor flux are derived as a function of the desired torque, and a modified torque-flux controller for the saturated machine is developed. The flux reference calculation method to achieve simultaneously an asymptotic field orientation, torque-flux decoupling and MTPA optimization in steady state is proposed. The method guarantees singularity-free operation and can be used as means to improve stator current transients. Experimental tests prove the accuracy of the control over a full torque range and show successful compensation of the magnetizing inductance variations caused by saturation. The proposed MTPA control algorithm also demonstrates a decoupling of the torque (speed) and flux dynamics to ensure asymptotic torque tracking. In addition, a higher torque per Ampere ratio is achieved together with an improved efficiency of electromechanical energy conversion

Maximum torque-per-amp tracking control of saturated induction motors

An improved maximum torque per Ampere (MTPA) controller for induction motor (IM) drives is presented. The proposed MTPA field oriented controller guarantees asymptotic torque tracking of smooth reference trajectories and maximises the torque per Ampere ratio when the developed torque is constant or slow varying. Due to use closed loop flux observer and high-gain PI controllers for both stator current components the proposed solution provides improved robustness with respect to parameters variations and inverter non-idealities. Experimental tests prove the accuracy of the proposed control over a full torque range. In addition, a higher torque per Ampere ratio is achieved together with an improved efficiency of electromechanical energy conversion

Robust indirect field oriented control of induction generator

The paper presents a novel robust field oriented vector control for induction generators. The proposed controller exploits the concept of indirect field orientation and guarantees asymptotic DC-link voltage regulations when DC-load is constant or slowly varying. An output-feedback linearizing Lyapunov’s based technique is employed for the voltage controller design. Flux subsystem design provides robustness with respect to rotor resistance variations. Decomposition of the voltage and current-flux subsystems, based on the two-time scale separation, allows to use a simple controllers tuning procedure. Results of comparative experimental study with standard indirect field oriented control are presented. It is shown that in contrast to existing solutions designed controller provides system performances stabilization when speed and flux are varying. Experimentally shown that robust field oriented controller ensures robust flux regulation and robust stabilization of the torque current dynamics leading to improved energy efficiency of the electromechanical conversion process. Proposed controller is suitable for energy generation systems with variable speed operation

Dynamic output feedback linearizing control of saturated induction motors with torque per ampere ratio maximization

The paper presents a novel maximum torque per Ampere (MTA) controller for induction motor (IM) drives. The proposed controller exploits the concept of direct (observer based) field orientation and guarantees asymptotic torque tracking of smooth reference trajectories and maximizes the torque per Ampere ratio when the developed torque is constant or slowly varying. A dynamic output-feedback linearizing technique is employed for the torque subsystem design. In order to improve torque tracking accuracy a motor magnetizing curve is taken into account during MTA optimization and controller design. The achieved steady-state system efficiency have been compared experimentally for three types of controllers, namely: standard vector control with constant flux operation, controller based on classic maximization of torque per Ampere ratio for linear magnetic circuit and controller based on MTA strategy for saturated induction motor. It is shown experimentally that the controller designed for saturated induction motor provides not only higher torque per Ampere ratio but also increases power factor and reduces active power consumption hence improving the drive efficiency. Operation with slowly varying torque references has also been analysed. It is shown that the proposed controller is suitable for applications that do not demand an extremely fast dynamic response, for example for electric vehicle drives

2018 IEEE International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles & International Transportation Electrification Conference (ESARS-ITEC)

This is a post-peer-review, pre-copyedit version of an article published in Proceedings of 2018 IEEE International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles & International Transportation Electrification Conference (ESARS-ITEC). The final authenticated version is available online at: https://ieeexplore.ieee.org/document/8607640A novel speed-flux tracking controller for induction motors has been developed and experimentally verified. Direct rotor flux field oriented controller is designed for current-fed induction motor model on the base of full order hybrid continuous time-sliding mode flux observer. Controller guarantees local asymptotic speed-flux tracking and asymptotic direct field-orientation under condition of unknown constant load torque. The flux subsystem is invariant with respect to limited rotor resistance variations due to special structure of the flux observer. The efficiency of the proposed solution is confirmed by the results of experimental studies, which demonstrate the improved robustness properties in all motor operating conditions including nearby zero speeds

Дослідження властивостей аустенітної сталі у вихідному стані

High-manganese steel is characterized by a stable austenitic structure over a wide temperature range and the ability to strengthen during mechanical deformation. However, factors such as unstable mechanical properties in the initial state, susceptibility to thermal embrittlement, and poor machinability hinder its widespread use. This study investigates the effect of temperature-time parameters on the structure and properties of 9Г28Ю9МВБ steel. It was found that during slow cooling from temperatures of hot deformation, a large number of coarse phase particles of gray-blue color are precipitated in the steel, leading to a sharp decrease in impact toughness. It has been established that in the temperature range of 500-800 °C, the decomposition of the solid solution occurs with the precipitation of particles of the strengthening K-phase - (Fe,Mn)3AL,Cx. Simultaneous decrease in hardness and impact toughness in the temperature range of 750-950 °C contributes significantly to improved machinability. The lowest values of mechanical properties are achieved during aging at 700 °C, with the maximum improvement in machinability compared to other aging temperatures. For example, with an increase in the temperature of isothermal holding at 650 °C for 35 hours, the machinability improves by almost 1.7 times, and at the same duration at 700 °C - by 2.4 times. With an increase in the holding temperature to 950 °C for 35 hours, the machinability of the steel increases only by 1.6 times, which is due to less intensive decomposition of the supersaturated solid solution. Studies of the effect of annealing temperature on the uniformity of austenitic steel allowed to develop a heat treatment regimen for 9Г28Ю9МВБ austenitic steel, which includes heating to 1250°C, holding for 2 hours at this temperature, and subsequent cooling in water to fix a homogeneous supersaturated solid solution. After such heat treatment, the stripe-like microchemical inhomogeneity is significantly reduced, and the anisotropy coefficient does not exceed 1.1 units for all types of steel products.Високомарганцева сталь в ракетно-космічній та оборонній галузях відзначається стабільною аустенітною структурою при великому діапазоні температур та здатністю до зміцнення під час механічної деформації. Однак широкому застосуванню цієї сталі заважають такі чинники, як нестабільність механічних властивостей у вихідному стані, схильність до теплового окрихчення та погана оброблюваність. У цій роботі досліджується вплив температурно-часових параметрів на структуру та властивості сталі 9Г28Ю9МВБ. Виявлено, що при уповільненому охолодженні від температур гарячої деформації сталі відбувається виділення великої кількості часток грубої фази сіро-блакитного кольору, що призводить до різкого зниження ударної в\u27язкості. Встановлено, що в інтервалі температур 500–800 ºС відбувається розпад твердого розчину з виділенням часток зміцнювальної К-фази - (Fe,Mn)3AL,Cx. Одночасне зниження твердості і ударної в\u27язкості в інтервалі температур 750–950 ºС сприяє значному покращенню оброблюваності різанням. Найменші значення механічних властивостей досягаються в процесі старіння при 700 ºС, покращення оброблюваності в цьому разі максимальне у порівнянні з іншими температурами старіння. Зі збільшенням температури ізотермічної витримки при 650 ºС до 35 годин оброблюваність покращується майже в 1,7 разу, а при тій же тривалості при 700 ºС - в 2,4 рази. При збільшеній температурі витримки до 950 ºС за 35 годин оброблюваність сталі підвищується тільки в 1,6 рази, що пов\u27язано з менш інтенсивним розпадом пересиченого твердого розчину. Дослідження впливу температури відпалу на однорідність аустенітної сталі дозволили розробити режим термічної обробки аустенітної сталі 9Г28Ю9МВБ, який включає нагрів до 1250°С, витримку протягом 2 годин при цій температурі і наступне охолодження у воді для фіксації однорідного пересиченого твердого розчину. Після такої термообробки мікроструктурна неоднорідність значно зменшується, коефіцієнт анізотропії не перевищує 1,1 одиниці для всіх видів сортаменту сталі