FCS-MPC Based IM-PMSM Dual-Motor System with Torque Optimal Control

This paper proposes a finite set model predictive control (FS-MPC) based thrust maximization technique for linear induction machines used in linear metros. For modeling of the proposed control method, the end effect is taken into consideration. The proposed control method is used to achieve maximum thrust per ampere and to reduce the thrust ripples. It differs from the FS-MPC methods, where the cost function consists of the thrust and angle errors. The thrust error is calculated from the difference between the reference thrust and the predicted thrust, and the angle error is calculated from the difference between the angle of predicted primary current and the angle of the predicted secondary flux in one side and π/4 on the other side. A comparison between the proposed method and the finite set model predictive direct thrust control (FS-MPDTC) is presented to illustrate the superiority of the proposed method. Both simulation and experimental analysis are conducted to validate the effectiveness of the proposed finite set model predictive direct angle control (FS-MPDAC). A prototype test platform is developed in the laboratory with two 3 kW arc induction motors. The simulation model, experimental test platform, and test results are presented in this paper.

A direct torque control (DTC) with a modified finite set model predictive strategy is proposed in this paper. The eight voltage space vectors of two-level inverters are taken as the finite control set and applied to the model predictive direct torque control of a permanent magnet synchronous motor (PMSM). The duty cycle of each voltage vector in the finite set can be estimated by a cost function, which is designed based on factors including the torque error, maximum torque per ampere (MTPA), and stator current constraints. Lyapunov control theory is introduced in the determination of the weight coefficients of the cost function to guarantee stability, and thus the optimal voltage vector reference value of the inverter is obtained. Compared with the conventional finite control set model predictive control (FCS-MPC) method, the torque ripple is reduced and the robustness of the system is clearly improved. Finally, the simulation and experimental results verify the effectiveness of the proposed control scheme.

Finite Control Set-Model Predictive Speed Control for Induction Motors with Optimal Duration

This paper presents a new robust adaptive current control strategy for induction motor drive systems. This control scheme is based on an adaptive pole placement control strategy (APPC) integrated to a sliding mode control scheme (SMC). The proposed APPC employs the internal model principle for achieving a zero steady state tracking error of machine stator currents. Moreover, this current controller can be implemented on the stator reference frame transformations. With this control scheme, fast transient response and robustness to parametric uncertainties and unmodeled disturbances are obtained. These disturbance can be owing to saturation, temperature changes or loading conditions. Simulation and experimental results are presented for showing the effectiveness of the proposed close-loop current control strategy.

This paper proposes a torque control method for surface mounted permanent magnetic synchronous motor (PMSM) driven by a 2-level voltage source driven inverter, which has fast torque response and small torque ripple. The proposed torque control method follows the finite control set model predictive control (FCS-MPC) strategy. A reference state is derived at each time step for the given time varying torque reference and the cost index is defined so that the tracking error for this reference state should be penalized. The choice of an optimal output voltage vector is made first from the 6 possible active voltage vectors of the 2-level voltage source inverter. Then a modulation factor for the chosen optimal voltage vector is obtained so that the torque ripple can be reduced further. It is shown that the proposed FCS-MPC control method yields fast torque tracking response and small torque ripple through simulation and experiments.

This paper proposes a finite control set model predictive control (FCS-MPC) to guarantee the stability and robustness for surface-mounted permanent magnet synchronous motor (SPMSM) drives. Continuous-input-based control laws are first developed from a control-Lyapunov function in order to both stabilize the closed-loop system via feedback control laws and ensure the robustness via online adaptive laws. Because the asymptotic stability of the proposed control method is guaranteed by at least one discrete switching-state, the continuous-input-based control laws are converted into relevant constraints of the FCS-MPC optimization problem. To validate the advantages of the proposed FCS-MPC, comparative studies with the conventional FCS-MPC and space vector modulation based adaptive control are conducted on a prototype SPMSM testbed with a TI TMS320F28335 DSP. The effectiveness of the proposed FCS-MPC is verified by the comparative schemes with/without the additional constraints. Superiority of the proposed schemes such as zero steady-state error, fast speed-tracking capability, well-regulated stator currents, and low average switching frequency are experimentally validated under the step-changes of load torque and speed reference.

In this paper, a new control strategy is proposed which is simple in structure and has the straightforward goal of minimizing the stator current amplitude for a given load torque. It is shown that the resulting induction motor efficiency is reasonably close to optimal and that the approach is insensitive to variations in rotor resistance. Although the torque response is not as fast as in field-oriented (FO) control strategies, the response is reasonably fast. In fact, if the mechanical time constant is large relative to the rotor time constant, which is frequently the case, the sacrifice in dynamic performance is insignificant relative to FO strategies.

Flux-weakening (FW) control has been utilized extensively in interior permanent magnet synchronous machine (IPMSM) control systems. To address the problems of poor dynamics and large overshoot of the conventional PI control system in the FW region, this paper presents a flux-weakening control strategy for IPMSM based on finite-control-set model predictive control (FCS-MPC). Firstly, the principle of FSC-MPC strategy is introduced. Secondly, the model prediction equation is proposed, the concept of cost function of FCS-MPC is developed and the implementation is given. Finally, the test results demonstrate that the performance of the FCS-MPC control strategy not only widen IPMSM's speed range, but also improve the dynamic performance compared to traditional PI control.

Deadbeat control (DBC) has been known for decades due to its conceptual simplicity and good performance. Recently finite control set model predictive control (FCS-MPC) is emerging as a powerful strategy for control of power converters. Different from DBC, which uses a modulator such as space vector modulation (SVM), FCS-MPC directly obtained the optimal switching states of power converters by minimizing a cost function. Several improved versions of FCS-MPC have been proposed to improve the steady state performance by introducing two or three vectors during one control period. This paper investigates the inherent relationship between SVM-DBC and multiple-vector FCS-MPC. It is found that with the aim of tracking error minimization, the two kinds of predictive methods can be unified in one frame, where the vector sequence and duration in FCS-MPC can be easily obtained from SVM-DBC. In other words, under some special cases, FCS-MPC and its improved versions can be considered as special cases of SVM-DBC. This is the main contribution of this paper, because DBC and FCS-MPC are previously studied separately. The theoretical study is confirmed by the analysis on state-of-the-art DBC and FCS-MPC and supported by the selected simulation study and experimental tests from a three-phase two-level voltage source PWM rectifier.

This paper deal with Backstepping control strategy for induction motor drive, using rotor flux and load torque observers. The proposed study uses a modified motor model with new variables, and Luenberger observers for both rotor flux and load torque. This work proposes a precise calculation method for controller parameters based on response time and damping coefficient. Simulation is performed in Simulink, results show that Backstepping works well by adding observers.

Induction motors are widely utilized in numerous applications due to their robustness, straightforward design, and affordability. Nevertheless, the precision of motor control can be affected by parameter mismatches and unmodeled system dynamics. Advanced control techniques like finite control set-model predictive control (FCS-MPC) have been designed to mitigate these issues. The FCS-MPC uses the system's mathematical model to predict future behavior of the system and select the most suitable control signal from a discrete set of options. Although FCS-MPC proves to be effective, traditional implementations can still face challenges from uncertainties such as parameter changes or external disturbances. This paper presents a novel robust predictive current control for induction motors in the stationary reference frame. It incorporates a discrete Luenberger observer to address the machine's parameter mismatches. A discrete-time voltage model is derived from the motor's dynamics, enabling the integration of a discrete Luenberger observer. This integration enhances controller performance, especially in the presence of parameter mismatches. In contrast to conventional FCS-MPC approaches, this method integrates stator voltage into the cost function instead of current, torque, or magnetic flux. Experimental results on an induction motor, tested under both steady-state and dynamic scenarios, confirm that this approach outperforms traditional predictive current control regarding robustness. The new method's enhanced control capability to better track the reference, even under significant variations in inductance and resistance, underscores its potential as an effective solution.

This report provides background information on various fractional-horsepower electric motor technologies used for evaporator fan applications in commercial refrigeration and summarizes data from a DOE-sponsored evaporator fan motor laboratory and field demonstration project. This report also extrapolates that data to project the potential economic and environmental benefits resulting from upgrading the current installed base of commercial refrigeration evaporator fan motors to permanent magnet synchronous (PMS) motors.Evaporator fan motors used in commercial refrigeration applications are fractional horsepower in size, responsible for moving air across the evaporator coil, and typically run at one speed. Historically, shaded-pole induction motors have been the most commonly used evaporator fan motors in commercial refrigeration equipment and beverage vending machines. These are the simplest and least expensive type of fractional-horsepower motor, with an efficiency of approximately 20%. Electronically commutated (EC) permanent magnet motors, also known as brushless DC motors, were initially commercialized in the late 1980s, and their use in commercial refrigeration applications has increased within the last 10 to 15 years because of economic incentives and regulatory requirements. State-of-the-art EC motors are approximately 66% efficient. Another induction motor type, the permanent split capacitor (PSC) motor, offers a mid-point between shaded-pole and EC motor price and efficiency levels. PSC motors are typically about 29% efficient.A permanent magnet synchronous (PMS) AC motor that can directly use grid-supplied AC current without the need to rectify to DC has recently been commercialized. This new motor exhibits a peak efficiency of 75% and has the potential to significantly reduce the energy consumption of evaporator fan motors in commercial refrigeration equipment. Laboratory evaluation of evaporator fan motor technologies was performed to quantify and compare the performance of shaded-pole, PSC, EC, and PMS evaporator fan motors in a controlled environment, so as to minimize the influence of external factors and anomalies. The laboratory evaluation included dynamometer testing of the fan motors and airflow testing of the motor/fan assemblies. It was found that the 6–12 W PMS motor exhibited a peak efficiency of 75% with a power factor of approximately 0.9 at a power output of 11 W. It was also found that a 38–50 W PMS motor exhibited a peak efficiency of 82% with a power factor of approximately 0.9 at a power output of 35 W.Airflow testing of shaded-pole, PSC, EC, and PMS motor/fan assemblies was performed using an airflow test chamber, which was designed in accordance with ANSI/AMCA Standard 210-16/ASHRAE Standard 51-16, to measure the performance of the subject motor/fan assembly and to determine the incumbent display case system impedance (AMCA 2016). A family of fan curves (static pressure vs airflow rate and electrical power input vs airflow rate) was generated for the 6–12 W PMS motor/fan assemblies with 8-inch fan blades pitched from 17 to 32 degrees. A similar set of curves was generated for the 38–50 W motors paired with 10 and 12-inch blades. Various incumbent motor/fan assemblies were also tested in the laboratory airflow test chamber and their fan curves were generated.Field evaluation of refrigerated display case evaporator fan motors was accomplished by performing side-by-side comparisons of 6–12 W PMS motors to 6–12 W shaded-pole and EC evaporator fan motors. It was found that, on average, a PMS motor consumes 79% less power and draws 82% less current than a shaded pole motor, and on average, 34% less power and 49% less current than an EC motor. In addition, the PMS motor exhibits an average power factor of approximately 0.82, which is on average 40% greater than that of existing evaporator fan motors.Two field test sites were selected to evaluate the performance of the larger 38 to 50 W PMS evaporator fan motors in walk-in cooler/freezer applications. At each supermarket, two walk-in units were selected for investigation: one walk-in dairy cooler and one walk-in freezer. A 61% decrease in fan motor power was measured when retrofitting existing evaporator fan motors with PMS motors in the walk-in cooler. In addition, a 48% decrease in fan motor power was measured when retrofitting existing evaporator fan motors with PMS motors in the walk-in freezer.The culmination of the field evaluation of fan motor technologies was a whole-store retrofit conducted at a supermarket. Pre- and post-retrofit measurement of evaporator fan motor power in medium- and low-temperature refrigerated display cases and walk-in coolers/freezers was performed. Overall for the whole-store retrofit, the current supplied to all monitored evaporator fan motors was reduced by 52%, the real power was reduced by 46% and the apparent power was reduced by 51% following the retrofit of the 262 evaporator fan motors that w

The paper presents an optimization of an indirect vector control strategy for induction motor drives. Based on the mathematic model of the induction motor which considers the iron loss resistance, a control algorithm has been conceived to reduce the difference between the measured and estimated torques. Two cases are presented in the paper. In the first case the iron loss resistance is neglected in the control algorithm, but it is considered in the second case. The indirect vector control algorithm was implemented on a dSPACE DS 1104 platform controlling an inverter fed 2.2 kW induction motor.

This paper proposes a sensorless vector control scheme for induction motor to operate at low speed. The integrator in the reference model of the rotor flux based Model Reference Adaptive System (MRAS) have the problems of dc drift and dead time. A new integration algorithm is developed for rotor flux based MRAS to reduce the effects of integrator. Multilevel inverter with space vector modulation technique is used to improve the performance of induction motor drive. Simulation study is carried out using SIMULINK and comparison study is made between classical rotor flux MRAS, new integration algorithm.

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.