Alfio Consoli

Industry application of zero-speed sensorless control techniques for PM synchronous motors

This paper presents the state of the art in the area of industrial applications of sensorless control for permanent-magnet synchronous motor (PMSM) drives. A new emerging technology is becoming mature to come to the market, based on high-frequency signal injection, that makes it possible to achieve zero-speed operation without increasing the complexity and the cost of the system. After an overview of major theoretical principles of sensorless control of PMSMs, the paper focuses on the practical implementation of one of the previously described high-frequency injection techniques in both salient and nonsalient PM machines. Experimental results are presented, including useful hints for practical implementation.

Reduction of common mode currents in PWM inverter motor drives

Modern PWM inverter motor drives are affected by dangerous common mode currents due to the high rate of variation of the modulated voltage. An inexpensive alternative to low pass filters which are normally used to limit common mode currents, consists in reducing such currents by using suitable modulation strategies. In the present paper a new approach for designing PWM strategies is presented able to reduce common mode currents by limiting the amount of variations of the common mode voltage. The main characteristics of the proposed approach are experimentally evaluated on a standard PWM induction motor drive.

Modeling and Simulation of Induction Motors with Saturable Leakage Reactances

A new method for the transient analysis of induction machines with saturating leakage reactances is presented. The equations which define operation under this condition are arranged so that the saturation of stator and rotor leakage as well as magnetizing reactance can be readily modeled with three function generators. The method is equally applicable to the analysis of synchronous machines.

Fuzzy adaptive vector control of induction motor drives

This paper deals with the design and experimental realization of a model reference adaptive control (MRAC) system for the speed control of indirect field-oriented (IFO) induction motor drives based on using fuzzy laws for the adaptive process and a neuro-fuzzy procedure to optimize the fuzzy rules. Variation of the rotor time constant is also accounted for by performing a fuzzy fusion of three simple compensation strategies. A performance comparison between the new controller and a conventional MRAC control scheme is carried out by extensive simulations confirming the superiority of the proposed fuzzy adaptive regulator. A prototype based on an induction motor drive has been assembled and used to practically verify the features of the proposed control strategy.

Low and zero speed sensorless control of synchronous reluctance motors

The paper presents a position sensorless vector control able to drive synchronous reluctance motors in any working condition, including low and zero speed operations. The proposed control scheme is based on calculating the rotor position from the measurement of an additional high frequency stator current component and allows a low cost implementation, moreover it does not require the knowledge of any motor parameter. Simulation and experimental results on a 1.5 kW prototype are presented to evaluate the consistence of the developed technique.

A robust adaptive controller for PM motor drives in robotic applications

The paper deals with theoretical development and practical implementation of an adaptive speed and position regulator suitable for robotic applications. The proposed adaptive control scheme is characterized by a reduced amount of computation and is based on the model reference adaptive control approach to compensate the variations of the system parameters, such as inertia and torque constant. A disturbance torque observer is employed to balance the required load torque and reduce the complexity of the adaptive algorithm. Simulation tests of a robotic drive, including an interior type permanent magnet synchronous (IPMS) motor, are reported in order to compare the proposed control scheme with standard speed and position regulators. Experimental results, obtained from a prototype based on a commercial PC board, are also reported in order to practically evaluate the feasibility and the features of the proposed adaptive control scheme. >

Sensorless vector and speed control of brushless motor drives

In the present paper an approach is presented to the speed control of permanent magnet synchronous motors without mechanical transducers. The rotor position, which is an essential component of any vector control scheme, is calculated through the instantaneous stator flux position and an estimated value of the load angle. A closed-loop state observer is implemented to compute the speed feedback signal. Experimental results on a laboratory tested motor drive are presented to validate the proposed procedure. >

Steady-State and Transient Operation of IPMSMs Under Maximum-Torque-per-Ampere Control

This paper analyzes different aspects of the maximum-torque-per-ampere (MTPA) vector control of interior permanent-magnet synchronous motors at steady state and transient. Two different implementations are considered: a nonlinear-model-based MTPA profile including saturation and cross-saturation effects and a technique based on the maximization of the motor input power versus stator current. Furthermore, this paper analyzes the torque evolution during a transient under an MTPA control strategy on motors with different characteristics. Useful modifications of the current loop are suggested to improve the drive performance. The effects of the torque transient on the sensorless rotor position estimation are also taken into consideration, in case a sensorless MTPA implementation is required. Experimental results confirm the theoretical analysis, showing the benefits of the new control schemes.

Soft-Switching Converter With HF Transformer for Grid-Connected Photovoltaic Systems

In this paper, the design, realization, and performance evaluation of a single-phase 3-kW dc/ac power converter, using an active-bridge dc/dc converter and a full-bridge dc/ac, are introduced, presenting a novel solution on the industrial scenario for the considered application. Control algorithms, including the maximum power point tracking, paralleling to the grid, and converter switching signals, are digitally implemented on a standard microcontroller.

An improved model of saturated induction machines

An improved equivalent circuit model is proposed which accounts not only for the saturation effects in the stator and rotor teeth but also for saturation in both the rotor and stator cores. The results obtained with the model are compared with test results as well as with results for more conventional models. The demonstrated improvement shows that detailed representations of saturation effects can be important in induction machine analysis, particularly when the machine is subjected to large signal disturbances.<<ETX>>