Field Oriented Vector Control Research Articles

Field-Oriented Control of a Nine-Phase Cage Induction Generator with Large Speed Changes and Variable Load

This paper presents a voltage control system for multiphase squirrel-cage induction generators operating at a high variability of speed and variable load. Field-oriented vector control was used with a change in the sequence of the stator phase currents what changes the number of poles of the magnetic field produced by nine-phase stator winding. At low speeds, the current sequence is changed so that the number of poles increases allowing for the desired voltage to be obtained with greater efficiency. The task of the automatic control system was to control the DC voltage to a desired value at the output of the multiphase PWM converter. This is an alternative control method to the scalar control of voltage and frequency presented in a previous work. The control method and parameters of the automatic control system result from the mathematical model of the multiphase induction machine. The results of the laboratory tests were compared with the effects of the operation of the same nine-phase scalar controlled generator.

Fitness distance balance-based Runge–Kutta algorithm for indirect rotor field-oriented vector control of three-phase induction motor

Fitness distance balance-based Runge–Kutta algorithm for indirect rotor field-oriented vector control of three-phase induction motor

Precise Control of Flat-Topped Air-Gap Magnetic Field in a Five-Phase Induction Machine Powered by Third-Harmonic-Injected Sinusoidal Supply

The third-harmonic-injected sinusoidal supply (THISS) can help make an innovative breakthrough to improve the power density of multiphase induction machines. However, the existing typical control approaches cannot guarantee the machine to precisely generate the expected flat-topped air-gap magnetic field under all operating conditions, which restricts the popularization of THISS. This article first converts the control objective from generating a flat-topped air-gap field to air-gap flux linkage alignment. In conventional approaches, the rotor leakage flux linkage is not fully considered, and subjective hypothesis is proposed, resulting in the misalignment between air-gap flux linkages components with different harmonic orders. Based on avoidance of exposed flaws and correct theoretical derivation, this article focuses on the spatial distribution of air-gap field and gives priority to the alignment of the air-gap flux linkage by means of harmonic air-gap field-oriented vector control. The required third-harmonic field can be calculated in real time through the fundamental field. Therefore, the flat-topped air-gap field is ensured by fundamental and harmonic current loops. Furthermore, the controllers in fundamental and harmonic current loops are decoupling with each other. The theoretical analysis and the proposed control approach are validated by simulation and experimental results in a five-phase induction machine (FPIM) powered by THISS.

Enhanced control of doubly fed induction generator based wind turbine system using soft computing assisted fractional order controller

This paper proposes teaching learning based optimization (TLBO) algorithm assisted fractional order controller for control of Rotor side converter (RSC) and Grid side converter (GSC) for efficient and optimal control of doubly fed induction machine based wind turbine (WT) system. The proposed fractional order proportional integral (FOPI) controller is tuned using Genetic algorithm (GA), particle swarm optimization (PSO) and TLBO techniques. The rotating reference frame with stator flux alignment dependent field oriented vector control scheme is accomplished for decoupled optimal power control. Proposed DFIG based WT system implemented and simulated using MATLAB/Simulink. Simulation results of proposed TLBO based fractional order control are compared with GA and PSO tuned FOPI controller. The simulation results obtained are expedient that TLBO tuned FOPI is more prominent in DC link voltage control and shown promising results as compared to GA and PSO tuned FOPI Controller in terms of the of the solution time required and time domain performance parameters.

Simulation Analysis and Optimization Design of the Variable-Speed Constant-Frequency Doubly Fed Wind Power Generation Control System Based on PSCAD

The depletion of nonrenewable energy and climate lead to increasingly bad environment. The efficient development of new energy has become an urgent problem to be solved. As a kind of new energy, how to effectively develop and utilize wind energy has aroused widespread concern all over the world. In this paper, a three-phase static a-b-c coordinate system is used for transformation. Taking the variable-speed constant-frequency doubly fed wind power generation system as the control object, the technology of generator power decoupling control is realized. The rotor side and grid side power converters adopt vector control methods based on stator flux orientation and grid voltage orientation, respectively. In this paper, the motion equation, flux equation, voltage equation, and electromagnetic torque equation of the motor are established. Vector-oriented control technology is used to control the generator. The control model of the VSCF doubly fed wind power generation system is established by using the simulation software PSCAD, and the simulation experiment is carried out. The feasibility of the power decoupling control method based on vector control is verified. The change trend of the active power of the power generation system is consistent with that of the wind speed, which shows that the control system has good stability. Using the field-oriented vector control method, the dual PWM controller can independently control the active power and reactive power. This greatly simplifies the nondecoupling control function equation in the expression. The dual PWM controller is well adjusted to minimize the power loss of the wind power generation system.

Active and Reactive Power Control for Wind Turbines Based DFIG Using LQR Controller with Optimal Gain-Scheduling

This paper proposes an optimal gain-scheduling for linear quadratic regulator (LQR) control framework to improve the performance of wind turbines based Doubly Fed Induction Generator (DFIG). Active and reactive power decoupling is performed using the field-oriented vector control which is used to simplify DFIG’s nonlinearity and derive a compact linearized state-space model. The performance of the optimal controller represented by a linear quadratic regulator is further enhanced using the whale optimization algorithm in a multiobjective optimization environment. Adaptiveness against wind speed variation is achieved in an offline training process at a discretized wind speed domain. Lookup tables are used to store the optimal controller parameter and called upon during the online implementation. The control framework further integrates the effects of pitch angle control mechanism for active power ancillary services and possible improvements on reactive power support. The results of the proposed control framework improve the overall performance of the system compared to the conventional PI controller. Comparison is performed using the MATLAB Simulink platform.

MATLAB SIMULATION RESEARCH ON PERMANENT MAGNET SYNCHRONOUS MOTOR VECTOR CONTROL

According to the mathematical model of PMSM (permanent magnet synchronous motor) and vector control method, PMSM FOC (vector control) simulation model is built on the basis of MATLAB/Simulink environment. The system adopts the rotor field oriented vector control method of id 0 to realize PMSM decoupling control. The speed regulator and current regulator uses the conventional PI control algorithm, and the inverter adopts SVPWM modulation strategies. The simulation results proved the feasibility of the control method, which provides a good theoretical basis for the parameters of PMSM control system hardware settings. At the same time, building simulation model PMSM FOC SPWM modulation strategy on the basis of FOC SPVWM simulation, making FFT (spectrum analysis) comparison between which and the SVPWM modulation's single phase current. The result that the output harmonic of SVPWM modulation is far less than SPWM modulation proves the advantages of SVPWM modulation strategies. 

SIMULATION OF PERMANENT MAGNET SYNCHRONOUS MOTOR FIELD ORIENTED VECTOR CONTROL SYSTEM

This template illustrates the control system of permanent magnet synchronous motor(PMSM) which uses field oriented vector control(field oriented vector control). PMSM is a complex, strong coupling and nonlinear system. And field oriented vector control could provide good performance as well as the PI controller setted with well parameter matching. Whereas limited by the number of voltage vector, the other control method of PMSM, direct torque control, could not satisfy accurate control when the machine running with a low speed. So modulation of the whole system is built here to realize closed-loop field oriented vector control control by keeping id 0 , and the machine model and the transformation among different coordinate system are discussed. The system is verified effective and feasible.

ROBUST DIRECT FIELD ORIENTED CONTROL OF INDUCTION GENERATOR

A novel and robust field oriented vector control method for standalone induction generators (IG) is presented. The proposed controller exploits the concept of direct field orientation and provides asymptotic rotor flux modulus and DC-link voltage regulations when a DC-load is constant or slowly varying. Flux subsystem, designed using Lyapunov’s second method, has, in contrast to standard structures, closed loop properties and therefore is robust with respect to rotor resistance variations. A decomposition approach on the base of the two-time scale separation of the voltage and torque current dynamics is used for design of the voltage subsystem. The feedback linearizing voltage controller is designed using a steady state IG power balance equation. The resulting quasi-linear dynamics of the voltage control loop allows use of simple controllers tuning procedure and provides an improved dynamic performance for variable speed and flux operation. Results of a comparative experimental study with standard indirect field oriented control are presented. In contrast to existing solutions, the designed controller provides system performances stabilization when speed and flux are varying. It is experimentally shown that a robust field oriented controller ensures robust flux regulation and robust stabilization of the torque current dynamics leading to improved energy efficiency of the electromechanical conversion process. The proposed controller is suitable for energy generation systems with variable speed operation. References 18, figures 8.

An FTC Design via Multiple SOGIs with Suppression of Harmonic Disturbances for Five-Phase PMSG-Based Tidal Current Applications

This paper firstly adopts a fault accommodation structure, a five-phase permanent magnet synchronous generator (PMSG) with trapezoidal back-electromagnetic forces, in order to enhance the fault tolerance of tidal current energy conversion systems. Meanwhile, a fault-tolerant control (FTC) method is proposed using multiple second-order generalized integrators (multiple SOGIs) to further improve the systematic fault tolerance. Then, additional harmonic disturbances from phase current or back-electromagnetic forces in original and Park’s frames are characterized under a single-phase open condition. Relying on a classical field-oriented vector control scheme, fault-tolerant composite controllers are then reconfigured using multiple SOGIs by compensating q-axis control commands. Finally, a real power-scale simulation setup with a gearless back-to-back tidal current energy conversion chain and a small power-scale laboratory prototype in machine side are established to comprehensively validate feasibility and fault tolerance of the proposed method. Simulation results show that the proposed method is able to suppress the main harmonic disturbances and maintain a satisfactory fault tolerance when third harmonic flux varies. Experimental results reveal that the proposed model-free fault-tolerant design is simple to implement, which contributes to better fault-tolerant behaviors, higher power quality and lower copper losses. The main advantage of the multiple SOGIs lies in convenient online implementation and efficient multi-harmonic extractions, without considering system’s model parameters. The proposed FTC design provides a model-free fault-tolerant solution to the energy harvested process of actual tidal current energy conversion systems under different working conditions.

Dead-Time Compensation Based on a Modified Multiple Complex Coefficient Filter for Permanent Magnet Synchronous Machine Drives

In field-oriented vector control of permanent magnet synchronous machine (PMSM) drives, the dead time will cause the 5th and 7th current harmonics in the stationary reference frame. They are mapped to the negative and positive 6th harmonic current in the synchronous reference frame (SynRF), resulting in torque ripple and deterioration of control performance. To solve this problem, a new dead-time compensation method is proposed in this article. First, a multiple complex coefficient filter is modified with a low-pass filter being paralleled to extract positive and negative sequence components of 6th harmonic from <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> -axes currents. Then, based on the extracted harmonics, a voltage feedback path with variable gains is designed in SynRF to eliminate the dead-time effect. Finally, the proposed method is implemented in a prototyped PMSM drive to verify its effectiveness. Both the simulations and experiments indicate that the proposed method can significantly weaken the dead-time effect with no additional hardware. Besides, it is also proved robust to the variable machine parameters.

Universal Control of Permanent Magnet Synchronous Motors with Uncertain Dynamics

This paper focuses on the universal control design of permanent magnet synchronous motors (PMSMs) with uncertain system dynamics. In vector control, classical proportional-integral (PI) controllers are used to control d-q axis currents and speed of the PMSM. This paper uses two control methods: conventional field-oriented vector control and simplified control. First, all the control gains are determined for numerous PMSMs with various power ratings using an empirical study and generalized mathematical expressions are derived for each of the gains. Then, these expressions are used for automatic gain calculation for various PMSMs with a wide power-rating range. In vector control, the control gains are determined using only the motor power ratings. In the simplified control, generalized control gain expressions are obtained using the number of pole pairs and the flux linkage. Compared to the vector control, the simplified control method provides much simpler generalized mathematical expressions. Validation is carried out in MATLAB/Simulink environment using various PMSMs from 0.2 HP to 10 HP, and results show accurate tracking of reference speed and d-q axis reference currents. Thus, the proposed gain scheduling approach is effective and can be used for self-commissioning motor drives.

Z-Source Inverter for Energy Management and Vector Control for Electric Vehicle Based PMSM

Electric vehicles have gained considerable attention recently due to the ever increasing demand for a viable alternative to the current fossil fuel-dependent modes of transportation. These automobiles are reliant on power electronics to generate the energy required for the motor. Traditional converters, namely the V-source (VS) and C-source (CS), are vulnerable to EMI noise, their main circuits cannot be interchangeable and they are either a boost or a buck converter. Therefore, their output voltage is strictly higher or lower than the input voltage. In an effort to negate these drawbacks, new inverters such as the Z-source were conceptualized. This work aims to study the applicability of the Z-source in the traction chain of an electric vehicle in order to feed a permanent magnet synchronous motor (PMSM). The latter is controlled with field oriented vector control reinforced with a backstepping technique in an attempt to ensure tracking ability and robustness. Energy management is also supported in this article in an effort to optimize the performance of the electric vehicle under different operating conditions. The simulation results show the effectiveness of the proposed system in enhancing the energy management of the vehicle, in addition to its simplicity which can facilitate an eventual implementation using a DSP or a Dspace platform.

An Improved Adaptive Sliding Mode Observer for Middle- and High-Speed Rotor Tracking

In this article, a sensorless field-oriented vector control strategy combined with an improved adaptive sliding mode observer and a back electromotive force (back EMF) observer is presented for a surface permanent magnet synchronous motor. First, based on a sliding mode, a current adaptive observer with estimation of back EMF is proposed to obtain the error of the back EMF, which can reduce system chattering. Then, a back EMF observer based on the back EMF error is constructed to adaptively track the rotor speed and position, which avoids complicated computation. Moreover, the stability of two observers is proved by using the Lyapunov stability theory. Finally, some simulations and experiments are given to show that the proposed method can track the changes of rotor speed and position with good characters, such as fast convergence, little chattering, and good robustness.

Simulation of PMSM Operating at Different Speeds and Optimization of PI Controller Parameters

This study aims to contribute to design and development studies by investigating current, speed and torque responses of permanent magnet synchronous motor (PMSM) with different loads and powers without any experimental study. For this reason, firstly, PMSM was simulated using Matlab/Simulink package program. The simulation results were then tested using a 0.25 kW PMSM coded MCS06C41, a motor driver coded EVS9322-ESV004, and the Global Drive Control interface program produced by Lenze. In addition, the model was tested on another PMSM (1.1 kW) to determine the validity of the model. Since the driver used during the experiment was designed according to field-oriented vector control, the field-oriented vector control was also preferred in the simulation. The PI controller parameters in driver simulation were optimized by using the Signal Constraint Block in Simulink Response Optimization toolbox of Matlab.

The weighted synergetic speed control for single inverter, parallel-connected induction motor drive

In the case of unbalanced load performance, the key issue in speed control of a single inverter-powered parallel motor coupling system is how to overcome the difference in motor parameters and the effect of slip between the induction motors to maintain the same speed. Based on the synergetic control theory and synergy manifold design techniques, the model which is field-oriented vector control with reduced order induction is proposed, as well as a synergetic control strategy. Moreover, the accuracy of the rotor flux observation is one of the most important steps in the motor control. In order to improve the convergence speed of rotor flux error, a new flux observer based on the sliding mode theory is proposed. Introducing the Sig function instead of the symbol function, the sliding mode control technology is improved to observe rotor to eliminate the control chattering. Then, two motor speed coupling weighted synergetic control models are given by using the new weight vector of the parallel induction motor. These models can directly obtain the stator excitation current and torque current of the two motors. The simulation and experimental results show that the newly proposed motor synergetic control method has better steady operation performance, overcomes the shortcomings of the existing average vector control method in load imbalance and motor parameter difference and proves the validity and advancement of the design strategy.

Doubly fed induction wind generators model and field orientation vector control design and implementation on FPGA

Dynamic systems emulators are very efficient techniques to design a system that mimics a precise behaviour of real systems. Moreover, they are designed to reduce costs as well as to give more flexibility concerning experimental purpose. The objective of this work is to develop an FPGA-based system, that emulates the overall doubly fed induction generator (DFIG) and active and reactive power vector control scheme for wind generators applications. The advantage of such an approach is to design a system which is more open to structural changes, has the possibility to be changed and could be adapted to several operating scenarios at lower costs. The DFIG with vector control scheme have been modelled using Xilinx System Generator and implemented in FPGA. The efficiency of this approach is assessed, yet, proofed considering reference tracking attitude of the controlled machine comparing to software simulation technique.

Voltage Control of a Stand-Alone Cascaded Doubly Fed Induction Generator

This paper studies the cascaded doubly fed induction machine, operating as a brushless variable speed constant frequency generator supplying an isolated load. In isolated electric supply, the amplitude and frequency of the output voltage of the generator should be stabilized during the speed and/or load changing. Despite the complexity of the generator model, a simple indirect field-oriented vector control is elaborated to meet the output voltage requirements. Experimental results validate the proposed control approach. The study is extended to reveal the behavior of the controlled system under unbalanced load.

A novel sliding mode single-loop speed control method based on disturbance observer for permanent magnet synchronous motor drives

A novel speed control method based on sliding mode control and disturbance observer is studied for permanent magnet synchronous motor drives. Different from the conventional speed and current cascade control structure in the field-oriented vector control, the new controller adopts the single-loop control structure, in which the speed and quadrate axes current controllers are combined together. First, a multiple-surface sliding mode controller is designed for the speed control system of permanent magnet synchronous motor. Although the sliding mode controller has the strong robustness for the matched disturbance in the system, it still cannot deal with mismatched disturbance effectively, such as external load disturbance and some parameter variations. Thus, the disturbance observer is introduced to estimate the disturbance in the motor, which is designed by combining the proposed sliding mode controller. Finally, the effectiveness is tested under various conditions by both simulation and experiment. The results show that the designed controller has the fast transient response and robustness under different operating conditions.

Robust Nonlinear Sensorless MPPT Control with Unity Power Factor for Grid Connected DFIG Wind Turbines

This paper focuses on the sensorless maximum power point tracking (MPPT) and unity power factor operation of a grid connected wind energy conversion system based on the doubly fed induction generator (DFIG). The proposed investigation is based on the nonlinear mathematical models of the wind turbine, the DFIG and the inverters. Based on the synchronized state-space model of DFIG and using stator field oriented vector control, an effective control of stator power is proposed. In this method, rotor speed, stator flux, and rotor resistance are estimated on-line. Field synchronization is provided by a three-phase PLL (Phase-Locked Loop). Unity power factor injection is achieved by controlling the power injected by the rotor and the closed-loop stability is ensured by Lyapunov analysis. Simulation results realized in MATLAB/SIMULINK environment, under different wind speeds, are presented and discussed. These results confirm the validity and effectiveness of the proposed controller.