Impact of the motor magnetic model on direct flux vector control of interior PM motors

The stator-field-oriented, direct-flux vector control has been proven to be effective in terms of linear torque control and model independent performance at limited voltage and current (i.e. in flux weakening) for AC drives of various types. The performance of the direct-flux vector control relies on the accuracy of the flux estimation, as for any field oriented control. The knowledge of the motor magnetic model is critical for flux estimation when the operating at low speed. This paper addresses the effects of a limited knowledge of the motor model on the performance of the control at low speed, for an Interior Permanent Magnet motor drive. Experimental results are give

Linear torque control of an interior permanent magnet synchronous motor

In this article is presented the linear torque control of an interior permanent magnet synchronous motor operating in the constant torque and field weakening ranges. The constant torque control is implemented by using the maximum torque per Ampère curve of the motor. The terminal stator voltage remains constant along the field weakening range by controlling the armature reaction control. In order to obtain a better dynamic response, the maximum torque per Ampère control is extended up to the field weakening range, called partial field weakening region. Experimental and simulation results are presented in order to validate the proposed torque control methods.Neste artigo é apresentado o controle linear de torque de um motor síncrono de ímãs permanentes interiores funcionando nas regiões de torque constante e de potência constante. O controle de torque constante é implementado através da curva de máximo torque por Ampère do motor. A tensão de terminal do estator é mantida constante ao longo da região de enfraquecimento mediante o controle da reação de armadura. Para melhorar a resposta dinâmica do controle, o controle de máximo torque por Ampère é estendido à região de enfraquecimento parcial de campo, que é uma região intermediária de velocidade. Resultados de simulação computacional e experimentais são obtidos com o objetivo de validar os métodos de controle propostos.26027

Genetic algorithm based approach of SRM current profiling for torque control and minimal copper losses

This paper presents a novel approach to current profiling for switched reluctance machines that eliminates torque ripple while inherently guaranteeing minimum copper losses, along with linear torque control. Minimization of copper losses increases machine efficiency, while eliminating torque ripple is the pre requisite for SRM use in applications such as traction vehicles. This paper presents theoretical optimal current profiles, initially without consideration of DC link voltage limitations. Utilizing a Genetic Algorithm in conjunction with current profiling limit envelopes, an optimized set of current profiles across the torque ripple free speed range of an exemplary 8/6 SRM is then created. The profiles characteristics are analyzed and compared with commonly used torque sharing function control to confirm the merits of the proposed method

High-performance motor drives

This article reviews the present state and trends in the development of key parts of controlled induction motor drive systems: converter topologies, modulation methods, as well as control and estimation techniques. Two- and multilevel voltage-source converters, current-source converters, and direct converters are described. The main part of all the produced electric energy is used to feed electric motors, and the conversion of electrical power into mechanical power involves motors ranges from less than 1 W up to several dozen megawatts

Zero Speed Rotor Position Estimator based on Sliding Mode Control for Permanent Magnet Synchronous Motor

The permImplementation of an algorithm based on SMC that uses a unique technique for the rotor position estimation of a PMSM for low and zero speeds, by using inherit motor effect called "Saliency". The work proves that the rotor position estimation is possible with the information that is present in the system under SMC due to the saliency effect. Therefore, there is no need to inject any signal into the machine, which causes the increment in the losses of the machine, or to design dynamic observers. The algorithm is implemented in a DSP controller and the tests with the complete hardware platform validate the proposal in open loop and in sensorless operation

Efficiency Optimization and Control of Permanent Magnet Synchronous Brushless Motors in Three-Phase Pulse Width Modulated Voltage Source Inverter Drives

In high performance drives where it is desirable to exploit the usefulness of reluctance torque and machine saliency, permanent magnet synchronous brushless motors are machines of choice. However, speed control of these machines especially in the flux weakening region becomes more complex due to the non-linear coupling among the winding currents as well as the nonlinearity present in the torque. While numerous research efforts in the past have considered control and efficiency improvements of induction motors, and synchronous motors with field windings, research efforts in developing an efficiency optimization and control strategy applicable to all salient-type permanent magnet synchronous brushless motors are still in their infancy.;A traditional control technique that has commonly been employed in efficiency improvement efforts is the stator\u27s zero d-axis current (i ds=0) technique. In this method, the rotor flux is aligned with the direct-axis so that the stator\u27s direct-axis current is zero and the torque becomes a linear function of the stator\u27s quadrature-axis current. Although this method achieves decoupling of winding currents and simplicity of control, it does not fully exploit the use of the machine\u27s saliency and reluctance torque, and is also not well-suited for wide-range load operations. The maximum torque per ampere (MTPA) technique is another less complex technique that has been considered which fully exploits the use of machine saliency with motor torque selected along the geometric curve of minimum-amplitude current space vectors for minimum loss operation. The drawback of the MTPA technique is that it does not provide high efficiency performance for synchronous reluctance motors running at low fractional loads.;In this work, the problem of efficiency optimization in the salient-type permanent magnet synchronous brushless motors is investigated. A machine model which includes the effect of core losses is proposed for developing a loss minimization algorithm that dynamically determines the optimal reference currents and voltages required for minimizing the total electrical losses (copper losses and core losses) within the feasible operating regions imposed by the motor and inverter capacities. The loss minimization strategy is implemented within a speed control loop for a synchronous reluctance motor drive and the effectiveness of the proposed scheme is validated by comparing performances with that of the traditional maximum torque per ampere and stator\u27s zero d-axis current vector control methods. It is shown that the proposed scheme offers the advantages of simplicity and superior performance throughout the entire operating range, and also improves motor efficiency to 96% at full load and full-speed operating condition

An Inverter Nonlinearity Independent Flux Observer for Direct Torque Controlled High Performance Interior Permanent Magnet Brushless AC Drives

This paper introduces a novel flux observer for direct torque controlled (DTC) interior permanent magnet brushless AC (IPM-BLAC) drives over a wide speed range including standstill. The observer takes machine nonlinearities into account and is independent of inverter nonlinearities, dead-time and armature resistance variation at steady-states since such inaccuracies are compensated quickly by measured phase currents. Magnetic saturations in the stator and rotor cores, cross-coupling effects of flux linkages of the motor and spatial harmonics in the magneto-motive force (MMF) are all considered in the novel scheme. There is no filter; hence no delays and oscillatory responses like in conventional schemes where filters are employed to prevent integrator drift issue. Superiority of the observer when compared to the state-of-the-art schemes has been illustrated by both extensive simulations and experimental results of a 10kW IPM-BLAC machine designed for traction applications

Efficiency and time-optimal control of fuel cell - compressor - electrical drive systems

The proton exchange membrane fuel cell (PEMFC) based power generation sys- tem is regarded as one of the perspective energy supply solutions for a wide variety of applications including distributed power plants and transport. The main compo- nent of the FC system is the FC stack, where the process of electrochemical energy conversion takes place. Additionally, such systems usually contain an auxiliary compression subsystem which supplies the reactant gases to the FC stack as well as maintains certain operation conditions: pressure, temperature, humidity, etc. The proper operation of the compression system signi¯cantly improves the performance characteristics of the total system. On the other hand, it consumes a portion of the electrical energy produced, thus reducing the net e±ciency of the total system. This thesis focuses on an innovative way to improve both the energy e±ciency and the response characteristics of a power generation system with a PEMFC. The approach principally consists of the control of the air compressor powered by the electrical drive. This method could be considered as an alternative to a redesign of the complete system (changing the power level, using an extra energy bu®er, etc). The modern high-speed centrifugal compressor has been regarded as one of the best candidates for the FC system. It has appropriate characteristics with respect to e±ciency, reliability, compact design, etc. However, the presence of a stability margin or so-called "surge line" limits its operation area. With the aim to overcome this constraint, a novel active surge suppression approach has been proposed for application in the system. This control method relies on the high-performance speed control of the electrical drive and accurate measurement and estimation of the thermodynamic quantities, such as air pressure and mass °ow. The choice of an induction motor drive has been justi¯ed by its commonly known advantages: low cost, simple construction, high reliability, etc. These features be- come especially important in high-speed applications. For the detailed investigation and performance prediction of the prime mover, a global electromagnetic design pro- cedure with thermal analysis of a high-speed induction motor has been performed. The obtained analytical results have been veri¯ed numerically by a high-precision Finite Elements Method. A good agreement between the analytical and FEM simu- lation results has been achieved. The mentioned active surge control in combination with the high-performance ¯eld-oriented control of the induction motor has been im- plemented and tested. The test bench comprises the centrifugal compressor with the PVC piping system, the high-speed induction motor drive, the real-time data acquisition and the control system. The experimental results proved the e®ective- ness of the active surge suppression by means of the drive torque actuation: the operation point of the compressor can be moved beyond the surge line while the process remains stable. Using the combined mathematical models of the FC stack, the centrifugal com- pressor and the ¯eld-oriented controlled induction motor drive, the static and dy- namic behavior of the total system have been simulated, allowing to clarify the interaction between the electrochemical processes in the FC stack, the thermody- namic processes in the compression system and the electromechanical performance of the drive. Various system operating regimes have been proposed and analyzed. When the FC electrical load changes frequently and fast, the constant-speed operating regime can be used. In case of a slow variation of the FC electrical load, the variable- speed operating regime is advisable, providing a high energy e±ciency at low FC load. In intermediate cases, the load-following-mass °ow operating regime with the application of the active surge control of the compressor becomes preferable. This operating regime eliminates the relatively long mechanical transient process, keep- ing the energy consumption of the balance of plant (BoP) approximately linearly proportional to the main load. The operating regime with applied linear quadratic Gaussian (LQG) time-optimal control has been proposed as an alternative to the load-following-mass °ow operating regime and the variable-speed operating regime. The transition between two steady-state operating points, where the system e±- ciency is maximum, follows the time-optimal trajectory, keeping the transient re- sponse time small. Finally, recommendations for further research have been formulated concerning the dynamic response and energy-e±ciency of a fuel cell system. Mainly, the recom- mendations concern further improvements of presented control strategies and their more comprehensive experimental veri¯cation using a complete FC system. First of all, the use of a direct induction motor drive for the compressor stabiliza- tion would signi¯cantly improve the e®ectiveness of the surge control. It would allow to control the surge of higher frequency, or to stabilize the compressor operation at larger distance from the surge line. Second, a combination of the electrical drive torque control with a valve position control would result probably in a more e®ective surge control, together with fast transients of the system operating point. Third, the application of the electrical drive for the compressor active surge control in a FC system would require new control algorithms for energy-e±ciency improvement of the induction motor, not compromising its high-performance capa- bilities

Digital control of gyroscope drift compsensation

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering, 1961.Includes bibliographical references (leaf 93).by Donald W. Fleischer.M.S

A linear maximum torque control of the interior permanent magnet synchronous motor

Orientador: Edson BimDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoResumo: Neste trabalho é apresentado o controle linear de máximo torque de um motor síncrono de ímãs permanentes interiores funcionando nas regiões de torque constante e potência constante. Na região de torque constante utiliza-se uma estratégia de controle baseada na curva de máximo torque por Ampére do motor e na região de potência constante implementa-se uma estratégia de enfraquecimento de campo que visa manter a tens~ao terminal de estator constante através do controle da reação de armadura. Para melhorar a resposta dinâmica do controle de torque na região de potência constante define-se uma faixa de velocidade intermediária, denominada região de enfraquecimento parcial, na qual estende-se o controle pela curva de máximo torque por Ampére. Resultados de simulação e experimentais são obtidos com o objetivo de avaliar os métodos de controle propostos.Abstract: In this work is presented the linear maximum torque control of an interior permanent magnet synchronous operating in the constant torque and field weakening ranges. The constant torque control is implemented by using the maximum torque per Ampére curve of the motor. The terminal stator voltage remains constant along the field weakening range due to the armature reaction control. In order to obtain a better dynamic response, the maximum torque per Ampére control is extended up to the field weakening range, in an intermediate region, called partial field weakening region. Experimental and simulation results are presented in order to validate the proposed torque control methods.MestradoEnergia EletricaMestre em Engenharia Elétric