Field Oriented Control Algorithm Research Articles

Sensorless induction motor drive for electric vehicle application

In this paper, an electric vehicle drive with a robust and low cost alternating current (AC) induction motor is presented. This approach is applied to an existing commercial utility electric vehicle where previously used direct current (DC) series motor was replaced by the new AC induction motor. The use of three-phase squirrel cage induction motor requires implementing of voltage source inverter supplied by DC voltage from vehicle battery system. A new DSP based voltage inverter is designed for the proposed drive. The used processor realizes the field oriented control algorithm with torque and flux closed loop control. The proposed drive does not require speed sensor, which make the solution and reliable on speed sensor faults. Motor speed is computed by the processor using speed observer. In this paper system description, control algorithms realization, and speed computation are presented. The paper includes the simulation and experimental results of the discussed system. Keywords: Electric vehicle, induction motor, field oriented control, sensorless control International Journal of Engineering, Science and Technology, Vol. 2, No. 10, 2010, pp. 20-34

Estimation of Rotor Position and Speed of Permanent Magnet Synchronous Motors With Guaranteed Stability

The control algorithms used in high performance ac drives require the knowledge of rotor position and, in the case of speed regulation, also of speed. Since in many applications rotational transducers cannot be installed, their reconstruction is needed. The use of observers is stymied by the fact that the dynamics of electrical machines are highly nonlinear and does not belong to the class studied by the nonlinear control community. In this paper solutions to both problems, which are particularly tailored for the widely popular permanent magnet synchronous motors, are provided. A key step for the design of both observers is the choice of a suitable set of coordinates. The position observer is a standard gradient search whose detailed analysis reveals outstanding (global asymptotic) stability properties. Furthermore, the analysis clearly exhibits the interplay between rotor speed and the gain of the gradient search-that (essentially) determines its convergence rate. The position observer is a simple two-dimensional nonlinear system, hence is easily implementable. The speed observer is designed following the immersion and invariance technique and is also shown to be globally convergent. Simulation and experimental results of the position observer, used together with a classical field-oriented control algorithm, are presented.

Performance Analysis of a Robust Positional Control with an Induction Actuator by Using a Simplified Indirect Field Oriented Control Algorithm

The aim of this paper is to study the performance of a simplified indirect field oriented control algorithm suited for small power induction actuators. The main particularities of the control strategy under study are the use of a disturbance observer in the speed and position control loops, and the absence of any current measurement. The good performance of the proposed control strategy, particularly as concerns the flux control sensitivity to parameter uncertainties, is shown by theoretical results and digital simulations.

FPGA-based field-oriented control for induction motor speed drive

In this paper, a flexible, high computation speed and cost effective field programmable gate array (FPGA)-based speed controller for an induction motor with field-oriented control, (FOC) is presented. All the control functions including the space vector modulation based PWM waveform generation, field-oriented control algorithm and rotor flux position estimation have been realized using FPGA to reduce the total part count of the hardware prototype and hence provide a low cost solution. The constructed FOC IC consists of 6844 logic elements and is realized using Cyclone, EPIC12q240C8 from Altera Inc. The sampling rate can be programmed up to 100MHz. Experimental result is included in this paper to illustrate the performance of the designed IC, FOCIC and the feasibility of integrating of SVM and FOC on single chip.

Using passive filters to minimize torque pulsations and noises in surface PMSM derived field oriented control

This paper describes a new dissipative passive filter system to minimize torque pulsation and current harmonic noises in surface PMSM when derived with field oriented control algorithm. The passive filter system consists of complex dissipative filter cascaded by low pass filter. The complex filter has two setting frequency points, one at inverter switching frequency and the other at some average selected frequency point. The filter system is affecting the inverter switching frequency in such a way to decrease stress on the inverter switching elements and reducing the severe of d v/d t on the motor. The filter system uses series dissipative elements to assist in reshaping of the applied voltage waveform in order to provide almost semi-sinusoidal voltage to the motor windings. The simulation results show that the proposed filter system is effectively minimized torque pulsations and harmonic noises in surface PMSM.

Theoretical and experimental comparison of indirect field-oriented controllers for induction motors

A theoretical and experimental comparison between standard and recently-developed improved indirect field-oriented controllers for induction motors is presented. It is shown that standard indirect field-oriented control algorithm provides asymptotic speed and flux regulation, while the improved one guarantees global exponential speed-flux tracking under condition of constant load torque. The difference between the flux sub-system design for the two controllers is analyzed. It is shown that the improved controller provides closed loop properties for flux subsystem when motor is rotating, leading to robust stabilization of the rotor flux vector space position and robust tracking of its modulus. It is demonstrated that both controllers have similar complexity and can be tuned using standard procedure for cascaded systems. Intensive experimental study shows that improved controller provides about one order higher speed tracking performance as compared with standard solution. Moreover, improved robustness with respect to rotor parameters variation leads to improved energy efficiency and robust stabilization of dynamic performance.

Output feedback control of current-fed induction motors with unknown rotor resistance

On the basis of a third-order reduced model of an induction motor (current-fed) the authors design an output feedback control (from rotor speed measurements) which guarantees global exponential tracking of speed and rotor flux modulus reference signals. An adaptive version is designed when load torque is constant and unknown. The rotor resistance, which is a crucial parameter for the control, is updated by a seventh-order dynamic estimator designed on the basis of speed, current, and voltage signals. The estimator provides exponentially convergent estimates in physical operating conditions. A good performance of the adaptive control algorithm using a sampling time of 0.5 ms is documented by experimental tests. Experiments show that the main advantage of the proposed control with respect to the classical field oriented control algorithm is the decoupling of speed and flux tracking; in addition, efficiency is improved in presence of rotor resistance variations.

Performance analysis of a simplified indirect field oriented control algorithm for small power induction actuators

The aim of this paper is to study the performance of a simplified indirect field oriented control algorithm suited for small power induction actuators. The main particularities of the control strategy under study are the use of a disturbance observer in the speed and position control loops, and the absence of any current measurement. The good performance of the proposed control strategy, particularly with regard to the flux control sensitivity to parameter uncertainties, is shown by theoretical results and digital simulations, and has been confirmed by experiments on a laboratory prototype.

Evaluation of a Transputer-based Embedded Controller for High Dynamic Control Applications

This paper evaluates a transputer-based controller and the implementation of a testbed problem comprising a digital Field Oriented Control algorithm for an induction motor. Although the control algorithm is implemented in Occam and in floating point on the controller it is still capable of achieving high real-time performance. The transputer provides the controller with significant advantages over other programmable controllers which cannot be readily extended to multiprocessor configurations without major software and hardware design effort. Emphasis is placed on the real-time and software engineering issues. Test results show that a high dynamic performance is achieved by the Induction Motor using this controller.