An innovative multiphase PWM control strategy for a PMSM with segmented stator windings

A new instantaneous torque-control strategy is presented for high-performance control of a permanent magnet (PM) synchronous motor. In order to deal with the torque pulsating problem of a PM synchronous motor in a low-speed region, new torque estimation and control techniques are proposed. The linkage flux of a PM synchronous motor is estimated using a model reference adaptive system technique, and the developed torque is instantaneously controlled by the proposed torque controller combining a variable structure control (VSC) with a space-vector pulse-width modulation (PWM). The proposed control provides the advantage of reducing the torque pulsation caused by the nonsinusoidal flux distribution. This control strategy is applied to the high-torque PM synchronous motor drive system for direct-drive applications and implemented by using a software of the digital signal processor (DSP) TMS320C30. The simulations and experiments are carried out for this system, and the results demonstrate the effectiveness of the proposed control.

This paper deals with the performance analysis of the field oriented control (FOC) of permanent magnet synchronous motor (PMSM) drive with a PID (proportional plus integral plus derivative) in DC link voltage control and fuzzy PID for speed control in closed loop operation. A mathematical model of the PMSM drive has been developed by considering each accessories of the model to analyze both the steady state and transient performances of the PMSM drive system. The current controlled inverter feeding power to the PMSM motor is powered from a PWM current controlled converter. The advantages of the integrated PMSM drive are demonstrated. The PID voltage control takes care of the constant DC link voltage to feed the inverter. The fuzzy controller provides a better response to the drive system specially in the steady state condition. The state space model developed in terms of derivatives of winding currents, DC link voltage, supply currents, rotor speed, and rotor position are simulated to obtain the required information. The study also examines the effectiveness of the PMSM drive under steady state and transient conditions for different parameter variation.

Sensorless technologies for the field-oriented control of the permanent magnet synchronous motors (PMSMs) are being actively developed today. Recently, a robust, nonlinear and globally convergent position observer for the surface-mount permanent magnet synchronous motor (SPMSM) has been proposed in [4]. The key feature of the robust observer is estimation of the rotor position requiring only the knowledge of the stator currents, voltages, resistance and inductance. However, the resistance and inductance of the stator may change during operation as a result of overheating, mechanical wear and environmental impacts. Thus, the aim of this study is to develop adaptive algorithms for the stator windings' parameters, which can be used for this position observer improvement. In this paper the authors propose four adaptive observers for estimation of the resistance and inductance at low motor speeds. It is assumed, that only currents and voltages of the stator windings are known. The other state variables and parameters of PMSM are unknown. The main idea of the synthesis of identification algorithms is linear filtering, which allows us to eliminate the unknown terms obtained by the mathematical transformations. Requirements to the external load, which ensure successful identification of the PMSM stator parameters, are given for each observer. The proposed adaptive observers for the stator resistance and inductance can be applied in case, when at low speeds, the field-oriented control of PMSM is carried out by means of Hall sensor, while at higher speeds, the sensorless control algorithms are used. A distinctive feature of the proposed estimation algorithms is that the resistance and inductance identification can be implemented during PMSM operation.

This paper presents a sensorless speed control of a permanent magnet synchronous motor using a sliding mode observer. A vector control strategy is considered, for a motor with sinusoidal flux distribution. The sliding mode observer detects the voltages induced by the magnet flux on the stator windings. These signals are used to calculate the rotor position and speed needed for vector control. Due to the sliding mode operation, filters are used to smooth the estimated variables. A speed-dependent compensation is also proposed, in order to achieve an accurate estimation of the rotor position. As the observed variables are not available below a limit frequency, an open loop starting procedure is implemented. The resulting observer has been fully analyzed by simulations, in order to test the performance both in steady-state and transient operations. Experimental results based on a DSP TMS320C50 controller are presented, showing the performance of the sensorless drive over a wide range of operating conditions.

A novel zero-voltage and zero-current soft-switching PWM DC-DC converter with low conduction losses is presented in this paper. A new interleaved two switch forward converter topology is developed to minimize circulating current with no additional auxiliary circuits. This converter has many advantages such as less components, better efficiency, high power density and cost effectiveness for high power applications. The principle of operation is illustrated together with steady-state analysis. Moreover, the effectiveness of the proposed converter topology is verified by implementing a 500 W-100 kHz breadboard.

An adaptive model-output-following controller using a variable structure system (VSS) approach is proposed in this paper. Only output from the plant is needed in the VSS control law to enhance the robustness of the control system. The position control of a permanent magnet (PM) synchronous motor servo drive using the proposed control strategy is illustrated. First, an integral-proportional (IP) position controller is systematically designed according to the prescribed drive specifications of the command tracking. Next, in order to allow the given specifications to be maintained under wide operating conditions, the state-space model of the systematically designed inner IP speed loop in the nominal case is chosen as the reference model. Then, the proposed adaptive controller based on VSS theory is designed and augmented to the inner speed loop to preserve the control performance. Simulation results show that the proposed control approach results accurately model the following characteristic and is robust with regard to plant parameter variations and external load disturbance.

This paper deals with theoretical analysis and design of permanent magnet (PM) synchronous motors (PMSMs) with minimized cogging force. Recently, many optimal designs for the PMSMs have been done by finite element (FE) analysis, but such analysis generally is time consuming. In this study, the equation of magnetic flux lines existing between PMs and iron cores is expressed geometrically and the cogging force is calculated theoretically without FE analysis. The form of equation is assumed to be the second-order polynomial and the virtual core is used to express the cogging force in analytical model. The cogging force can be calculated by applying the solved flux line equation and the flux density equation to the Lorentz force equation by using the Maxwell stress tensor. The theoretical analysis of minimized cogging force is applied to several prototypes such as synchronous PM planar motor (SPMPM), 2-DOF PMSM with screw motion, and axial flux PM (AFPM) brushless dc motor in this paper, and the analytical results are validated by FE analyses and experiments.

Presented in this paper are the results of tests involving high-speed closed-loop control of a virtual permanent magnet synchronous motor (PMSM) drive implemented on a field-programmable gate array (FPGA) card, connected to an external controller. Three types of motor drive models are actually implemented on the FPGA card of the RT-LAB based real-time simulator used: a Park (d-q) model along with two different implementations of finite element analysis (FEA) based models. The first FEA model, previously published, is an FPGA implementation of a FEA model with an inductance calculation routine running on an associated CPU of the real-time simulator. The second FEA model has its inductance routine coded in the FPGA. One of the main objectives of the paper will be to compare the performance of the two FEA models. By virtue of the faster, FPGA-located, inductance routine update rate of the new model, it is expected that its precision at very high speed will be greater than the previous model, which was shown to be limited to 400 Hz electric frequency.

Control of two PM linear motors with a single inverter: application to elevator doors

In order to estimate the vibration and acoustic noise in a permanent magnet (PM) synchronous motor, the natural frequencies of the stator structure should be determined during the design stage. In this paper, analytical formulas to predict the natural frequencies of the stator are derived. The analytical model of the stator includes stator teeth, winding, stator core, and stator case. It is observed that the natural frequencies calculated with the integrated components exceed those based on the stator core alone only. In order to verify this analytical model, numerical simulation and experimental measurement are carried out using a PM synchronous motor which has 5 pole-pairs and 12 slots structure configuration. Good agreements are observed among the results obtained by analytical formula, simulation and experiment.

The main object of this study is the design and the application of second order sliding mode controllers based on the super twisting algorithm for the vector control of synchronous permanent magnet motor fed by direct matrix converter, in order to get high performance in terms of specification required of dynamic behaviors. In this framework, thanks to its success with regard to its reduced conduction losses, the space vector modulation technique was chosen as a switching algorithm to control the matrix converter. On the other hand, a passive filter with a damping resistor has been inserted at the input of the matrix converter to prevent the injection of harmonics by the drive system into the grid. Finally, the effectiveness and feasibility of the proposed control approach for the considered drive system was examined and verified by simulation.

The sensorless control system of permanent magnet synchronous motor (PMSM) fed by current source inverter is presented in this paper. The adaptive backstepping control system and the backstepping speed observer are presented. The control systems are based on multiscalar variables. The control variables are dc-link voltage and the output current vector pulsation. The control system was named the voltage control system because of the fact that the first control variable is voltage in dc-link. The machine inverter is treated as a commutator. It works with constant modulation index. The proposed control system is robust on mechanical and electromagnetical parameters of the motor. The adaptive estimator of the stator resistance is introduced. Such an approach to control of the PMSM motor gives better performance. It is robust to dynamic uncertainties and does not require knowledge of the system parameters. The mathematical equation was introduced. Simple method limitation of control variables is explained. The reference variables must be limited to a constant or various value if the motor system has to be used in the industrial applications. The simulation and experimental test are shown.

Field-weakening mode of operation is an important feature of modern permanent magnet (PM) synchronous electrical drives, which overcomes speed limitation due to the lack of supplying voltage and increases their speed operational range. Therefore, field-weakening (FW) algorithm is an inalienable part of the overwhelming majority of control systems for PM synchronous motors. At the same time, seamless integration of the filed-weakening techniques into the conventional control systems is not considered well and some reported solutions may decrease system reaction time and cause stability issues. This paper proposes an improved field-weakening strategy, which includes optimized FW controller and novel current limitation strategy in the field-weakening mode. These features simplify structure of the resulting control scheme, decrease computational burden on the microcontrollers and decreases system reaction time, caused by wind-up of the speed controller operating in parallel with the conventional FW algorithms.

As one of the most important power equipment in industrial society, permanent magnet synchronous motor has a large number of uses in many fields. The traditional three-phase permanent magnet synchronous motor using vector control technology cannot meet the industrial high precision control requirements. So, the motor is analysed, the permanent magnet motor control model is constructed, and the chicken cluster algorithm is used to optimize the vector control parameters of the permanent magnet synchronous motor. Considering that the traditional cluster model faces the problem of local optimal solution, hypercube sampling and particle swarm model are used to optimize the chicken flock model, and an improved chicken flock motor control model is constructed to achieve efficient control of the motor. In the test of Rastrigin function, the particle swarm model, the traditional flock model and the improved flock model converge after 91, 72 and 20 iterations, respectively, and the best objective function values of 3.91e-4, 9.27e-5 and 1.79e-5 are obtained for the three models. The improved flock model has better convergence efficiency and convergence accuracy. In the test of different motor control methods, the overall fluctuation of the improved flock model is smaller, and the stability is improved by 31.65% compared with the traditional vector control, and 11.35% compared with the traditional flock model. The research content has important reference value for intelligent control of motors.

In this paper, a robust Fractional order sliding mode controller (FOSMC) is proposed for the speed control of a permanent magnet synchronous motor (PMSM). The sliding mode controller (SMC), which is insensitive to uncertainties, is studied widely in the application of PMSM drive. Furthermore, it is remarkable to see the increasing number of studies related to the theory and application of fractional order controller (FOC), especially PIλDμ controller, in many areas of science and engineering. Research activities are focused on developing new analysis and design methods for fractional order controllers as an extension of classical control theory. In this study, with the exponent reaching law, a fractional order sliding surface is introduced and a FOSMC is designed and applied to a speed control of PMSM, which is typical nonlinear multivariable coupled system. The performance and robustness of the proposed method are tested for nonlinear load torque disturbance, and simulation results show the effectiveness of the proposed algorithm.