Search results

The comparative analysis of field‐weakening (FW) in vector controlled and DTC permanent magnet synchronous motor drives is performed. The results of simulations and a comprehensive set of experiments are also given. The possibility of unstable operation in the high‐speed region using DTC is emphasised. The present paper also highlights some important differences between DTC and vector drives in FW, such as quickness of torque response, torque/flux/current ripple content and implementation aspects. For this purpose two types of DTC drives are implemented, a classical DTC and also a DTC scheme with torque ripple reduction.

Predictive controllers and permanent magnet synchronous motors (PMSMs) got more attention over the past decades thanks to their applicable features. This paper aims to propose and verify a method to design a predictive current controller with consideration of motor characteristics obtained from finite element analysis (FEA).

Permanent magnet motor parameters and its maps can be calculated by means of FEA. The model takes into account magnetic saturation and thermal electro-magnetic properties. For each dq current vector and each position, self and mutual inductances are calculated. Based on co-energy method and fundamentals of coordinate transformation dynamic and static, dq inductances are obtained. These are used in classical and modified dead-beat current controller equations.

To sustain good features of a controller over higher current regions, it is necessary to adapt control law of a dead-beat controller. After its modification, control quality can be superior over classical solution in high saturation regions. The transient simulations of controller and motor give accurate results.

Common predictive current controllers use nominal motor parameters in their equations. The authors proposed a modified dead-beat current controller to improve the control quality. There is no need to apply self-tuning algorithms, and implementation of the controller is not much more complicated than that of the classical controller. Designer of a control system can obtain required data from motor designer; in design process of modern machines such data are often already available. The proposed methodology increases control quality of the presented dead-beat controller.

The purpose of this paper is to discuss the design and verification of a non‐classical structure of servo‐drive controller with the state feedback and a load torque feedforward compensation.

First a well known nonlinear mathematical model of a PMSM is transformed into a linear form by introducing new variables. The state space new model presented in rotated orthogonal reference frame is decoupled by means of equation in d and q axis. To achieve correct dynamic performance of the servo‐drive system the state feedback with an internal input model and load torque feedforward compensation is proposed. The observed load torque has been used as an input signal for the feedforward compensator. The design of the control system and simulation analysis were performed in Matlab/Simulink. The proposed control algorithm was implemented in a DSP controller (TMS320F2812). The experiments were carried out by using a 0.6 kW PMSM drive system.

It is shown that the proposed compensator can eliminate the effects of load torque changes by steady‐state operation and significantly improve dynamic behaviour during load changing. A novel mathematical formula how calculate an appropriate gain for feedforward compensator is given.

Analysis of possible disturbance compensation shows that full dynamic compensation of disturbance is impossible. Only the compensation of load torque for a steady state is possible. The described control structure operates without state variables limitations so it is not recommended to application where the high dynamic of transient process is required.

The proposed control system can be used in industrial applications where load torque compensation is needed instead the high dynamic performance.

Presented mathematical formula how calculate an appropriate gain for feedforward compensator is a theoretical contribution of the authors. The test results are consistent with the computer simulation test results and validate the correct dynamic performance of the proposed control method.

The purpose of this paper is to elaborate a robust model‐based protective control algorithm for multi‐mass motor drives that are subjected to physical and safety constraints on their variables.

The algorithm relies on the off‐line computed maximum robust controlled invariant set or its approximation for the given drive system and imposed constraints. It can be used to patch any existing drive control scheme with a firm constraints satisfaction guarantee. The online patch implementation is actually a simple correction of the control signal computed with the existing control scheme, with a mandatory state observer.

Performance of the patch is tested on a two‐mass drive system in combination with classical two‐mass drive speed controllers – P+I and reduced state controller. All constraints violations that exist in the presented responses obtained without the protection patch are suppressed by using the patch which shows the effectiveness of the approach. A brief implementation analysis shows that a digital signal processor could be used for online implementation of the controller with the protective patch.

Robust invariant sets theory is efficiently and effectively used in a new application area – protection of multi‐mass electrical drives.

The purpose of this paper is to present a new finite element technique to simulate variable speed drives.

The induction motor (IM) is simulated according to the adopted control strategy. This allows use of only magnetostatic simulation for both no‐load and under‐load simulations.

The procedure allows the analysis of the performance of the IM drive taking into account iron saturation in all operation points.

The entire system design is considered in the paper, both the electrical machine and the control strategy.

The purpose of this paper is to obtain a fully sensorless permanent magnet synchronous motor (PMSM) drive control algorithm used for robot arm drive with load recognition. The paper shows how to use an extended Kalman filter (EKF) instead of sensors of the mechanical quantities as well as how to adapt the model of the PMSM to the filter procedures and aims at the real time application in the field‐oriented control (FOC) structure of the high‐dynamic drive.

The synthesis of the control system is based on the method of the FOC, theory of the EKF and object description in the form of state equation with suitable choice of state vector. The adequate connection of these three methodologies is a core of the approach to design. First, the control algorithm was tested by means of simulation method then the real laboratory plant was built and investigated.

Owing to task‐oriented formulation of the PMSM model, adequate organization of the EKF procedures and suitable choice of covariance matrices the proper control algorithm was obtained. The algorithm can be applied on DSP and gives a good result for the high dynamic drive in spite of the fact that the Kalman procedures are recognized as a time‐consumed solution of the estimation problem.

The proposed algorithm can be used also in the case of another type of drive, for instance induction motor drive, although the model of the motor has a different formula. A disadvantage of the method is lack of the general rules for choosing the elements of the covariance matrices.

The presented algorithm is written in open‐programming language. Obtained results may be important for synthesis of robot arm drive, where the information about load forces is needed.

The paper presents an original sensorless vector control of PMSM with load recognition based on EKF. The originality elements are the choice of the covariance matrix elements and the real‐time realisation of the algorithm on the DSP.

Fractional slot permanent magnet (PM) brushless machines having concentrated non‐overlapping windings have been the subject of research over last few years. They have already been employed in the commercial hybrid electric vehicles (HEVs) due to high‐torque density, high efficiency, low‐torque ripple, good flux‐weakening and fault‐tolerance performance. The purpose of this paper is to overview recent development and research challenges in such machines in terms of various structural and design features for electric vehicle (EV)/HEV applications.

In the paper, fractional slot PM brushless machines are overviewed according to the following main and sub‐topics: first, machine topologies: slot and pole number combinations, all and alternate teeth wound (double‐ and single‐layer windings), unequal tooth structure, modular stator, interior magnet rotor; second, machine parameters and control performance: winding inductances, flux‐weakening capability, fault‐tolerant performance; and third, parasitic effects: cogging torque, iron loss, rotor eddy current loss, unbalanced magnetic force, acoustic noise and vibration.

Many fractional slot PM machine topologies exist. Owing to rich mmf harmonics, fractional slot PM brushless machines exhibit relatively high rotor eddy current loss, potentially high unbalanced magnetic force and acoustic noise and vibration, while the reluctance torque component is relatively low or even negligible when an interior PM rotor is employed.

This is the first overview paper which systematically reviews the recent development and research challenges in fractional‐slot PM machines. It summarizes their various structural and design features for EV/HEV applications.

Small highly saturated interior permanent magnet- synchronous machines (IPMSMs) show a very nonlinear behaviour. Such machines are mostly controlled with a closed-loop cascade control, which is based on a d-q two-axis dynamic model with constant concentrated parameters to calculate the control parameters. This paper aims to present the identification of a complete current- and rotor position-dependent d-q dynamic model, which is derived by using a finite element method (FEM) simulation. The machine’s constant parameters are determined for an operation on the maximum torque per ampere (MTPA) curve. The obtained MTPA control performance was evaluated on the complete FEM-based nonlinear d-q model.

A FEM model was used to determine the nonlinear properties of the complete d-q dynamic model of the IPMSM. Furthermore, a fitting procedure based on the nonlinear MTPA curve is proposed to determine adequate constant parameters for MTPA operation of the IPMSM.

The current-dependent d-q dynamic model of the machine models the relevant dynamic behaviour of the complete current- and rotor position-dependent FEM-based d-q dynamic model. The most adequate control response was achieved while using the constant parameters fitted to the nonlinear MTPA curve by using the proposed method.

The effect on the motor’s steady-state and dynamic behaviour of differently complex d-q dynamic models was evaluated. A workflow to obtain constant set of parameters for the decoupled operation in the MTPA region was developed and their effect on the control response was analysed.

The purpose of the paper is to present a complete design example of an interior permanent magnet integrated starter‐alternator (ISA).

After a preliminary design on the basis of an analytical model, finite element simulations are adopted to refine the design of the machine.

The designed ISA drive is able to satisfy all the requirements of modern cars, where the power of the electrical generators is increasing to deliver the on‐board power demand. The drive exhibits high torque, driving start, and a wide constant power speed range driving generation.

The entire system design is considered in the paper, both the electrical machine and the control strategy.

The purpose of this paper is to introduce a new design optimization technique for a surface mounted permanent magnet (SMPM) machine to increase sensorless performance at high loadings by compromising with torque capability.

An SMPM parametric machine model was created and analysed by finite element analysis (FEA) software by means of the Matlab environment. Eight geometric parameters of the machine were optimized using genetic algorithms (GAs). The outer volume of the machine, namely copper loss per volume, was kept constant. In order to prevent sensorless performance loss at high loading, an optimization process was realized using two loading stages: maximum torque with minimum ripple at nominal load and maximum self-sensing capability at twice load. In order to show the effectiveness of the proposed technique, the obtained results were compared with the classical one-stage optimization realized for each loading condition separately.

With the proposed technique, fairly good performance results of the optimization were obtained when compared with the one-stage optimizations. Using the proposed technique, sensorless performance of the motor was highly increased by compromising torque capability for high loading. Additionally, this paper shows that the self-sensing properties of a SMPM machine should be considered at the design stage of the machine.

In related literature, design optimization studies for the sensorless capability of SMPM motor are very few. By increasing optimization performance, new proposed technique provides to achieve good result at high load for sensorless performance compromising torque capability.