Dead-time Compensation Method Based on Field Oriented Control Strategy

The field-oriented control (FOC) strategy of a permanent magnet synchronous motor (PMSM) in a simplified form is based on PI-type controllers. In addition to their low complexity (an advantage for real-time implementation), these controllers also provide limited performance due to the nonlinear character of the description equations of the PMSM model under the usual conditions of a relatively wide variation in the load torque and the high dynamics of the PMSM speed reference. Moreover, a number of significant improvements in the performance of PMSM control systems, also based on the FOC control strategy, are obtained if the controller of the speed control loop uses sliding mode control (SMC), and if the controllers for the inner control loops of id and iq currents are of the synergetic type. Furthermore, using such a control structure, very good performance of the PMSM control system is also obtained under conditions of parametric uncertainties and significant variations in the combined rotor-load moment of inertia and the load resistance. To improve the performance of the PMSM control system without using controllers having a more complicated mathematical description, the advantages provided by reinforcement learning (RL) for process control can also be used. This technique does not require the exact knowledge of the mathematical model of the controlled system or the type of uncertainties. The improvement in the performance of the PMSM control system based on the FOC-type strategy, both when using simple PI-type controllers or in the case of complex SMC or synergetic-type controllers, is achieved using the RL based on the Deep Deterministic Policy Gradient (DDPG). This improvement is obtained by using the correction signals provided by a trained reinforcement learning agent, which is added to the control signals ud, uq, and iqref. A speed observer is also implemented for estimating the PMSM rotor speed. The PMSM control structures are presented using the FOC-type strategy, both in the case of simple PI-type controllers and complex SMC or synergetic-type controllers, and numerical simulations performed in the MATLAB/Simulink environment show the improvements in the performance of the PMSM control system, even under conditions of parametric uncertainties, by using the RL-DDPG.

This article presents the sensorless control of a PMSM based on the FOC (Field Oriented Control) strategy and on PFC (Power Factor Correction), where the rotor speed is provided by speed observers. It presents the block structure of the PFC together with the numerical simulations achieved in Matlab/Simulink, on the improvement of the PF (Power Factor) of the supply circuit. It also presents the block structures of the FOC strategy and of the back-EMF (back electromotive force) sliding mode, MRAS (Model Reference Adaptive System), and PLL (Phase Locked Loop) type observers. The numerical simulations show the superiority of rotor speed estimation when using the back-EMF sliding mode observer compared to the rotor speed estimate provided by MRAS and PLL observers.

By combining field orientation control (FOC) strategy with fuzzy-PID hybrid control, a brushless DC motor hybrid control system based on FOC is designed in this paper. The implementation method is put forward, and system simulation model is established. The simulation results show the control performance of brushless DC motor control system based on fuzzy-PID hybrid control is better than the system based on traditional PID control, response being faster, torque ripple being smaller. STM32F103B is used as the control core to design the brushless DC motor hybrid control system based on FOC. A brushless DC motor PC (personal computer) monitoring system is designed by VB (Visual Basic). The measured current curve of system is consistent with theory, the measured result show the value of phase difference between two phase currents is 120 degrees, and current waveform is approximate sine wave. The speed curve from monitoring system shows good performance of designed system, response is fast, speed ripple is small, and operation is stable.

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.

In this thesis, a sensorless method for low and zero speed operation is proposed for a high-power medium-voltage pulse-width-modulated Current–Source-Converter (CSC)-fed Interior Permanent Magnet Motor (IPM) drive system. The proposed method is based on injection of a high-frequency (HF) pulsating sinusoidal signal into the estimated synchronous reference frame of the drive’s Field Oriented Control (FOC) scheme. The conventional FOC control scheme, low switching frequency, dc-link inductor and the inverter output three-phase filter capacitor of the medium-voltage high-power current-source drive present some challenges in the generation and design of the HF injection signal. To overcome the challenges, the FOC scheme is modified by introducing a modulation index control with a suitable dc-link current compensation to enhance the dynamic response of the injected signal and prevent any clamp in the injected signal. In addition, a Multisampling Space Vector Modulation (MS-SVM) method is proposed to prevent the distortion in the HF signal due to a low switching frequency to injected signal ratio. It is found that by using the proposed FOC scheme and multisampling modulation scheme, and proper design of the HF signal, an accurate rotor flux angle can be estimated for sensorless zero/low speed operation. Moreover, a novel input power factor compensation method is proposed for a high-power pulse-width-modulated Current-Source-Converter (CSC)-fed Permanent Magnet Synchronous Motor (PMSM) drive system. The proposed method is based on controlling the d-axis stator current component in the field-oriented control scheme of the drive system. The main feature of the proposed scheme is to compensate for the line-side power factor without the need for modulation index control in either the rectifier or the inverter. Simulation and experimental verification for various objectives are provided throughout the thesis. The results validate the proposed solutions for the main challenges of zero/low speed operation of sensorless Current-Source-Converter (CSC)-fed Permanent Magnet Synchronous Motor (PMSM) drive system.

In-depth cross-coupling analysis in high-performance induction motor control

Electric and hybrid-electric vehicles have a tendency to switch from the classic 12, 24 or 48V batteries to ones delivering high voltage ranging from 400V to 800V. At the same time, the reduction or elimination of critical materials such as Neodymium used in the manufacturing of Permanent Magnets (PM) is a very important factor, considering the low availability within the EU. In this context, a 560 Vdc fed Permanent Magnet Assisted Synchronous Reluctance Machine (PMASynRM) with interior Ferrite PM for light electric vehicles propulsion will be controlled using the Field Oriented Control (FOC) strategy and subjected to the New European Driving Cycle (NEDC) in order to evaluate its performances in a dynamic simulation scenario required for any automobile propulsion system in the EU.

Electric vehicles (EVs) have several advantages over fossil fuel vehicles, which reducing greenhouse gases and air pollutants. The selection of control systems play a pivotal role in the overall functionality, efficiency, safety, and user experience of electric vehicles. This study focuses on an EV with a two-wheel drive (TWD) configuration powered by a permanent magnet synchronous motor (PMSM) and a battery. The motors are controlled by a field-oriented control (FOC) method without a speed sensor, addressing common sensor issues. An electronic differential is included to maintain the balance of the EV during operation. This research mainly contributes to the integration of an extended Kalman filter (EKF) to solve the speed sensor issue in EVs based on FOC control. Additionally, the study addresses the challenge of determining the nine parameters of the FOC algorithm's controllers using the particle swarm optimizer (PSO) and grey wolf optimizer (GWO). The Kalman filter provided excellent stability for the EV, and the GWO achieved significant improvements: a 5% dicrease in speed error, a 10% dicrease in torque ripples, and a 9% improvement in current wave forme, compared to the PSO algorithm.

This paper raises a full-order flux linkage observer for the high-power electrically excited synchronous motor and proposes a design for its feedback matrix based on modern control theories which ensure excellent dynamic and static performances of this full-order flux linkage observer. On the basis of the said full-order flux linkage observer, an air gap field-oriented vector control strategy for the electrically excited synchronous motor based on the full-order flux linkage observer has been established and it is possible for the electrically excited synchronous motor to operate with the unity power factor. Through simulation and experiments, the effectiveness of the full-order flux linkage observer as well as the control strategy has been further verified. Key words: Electrically excited synchronous motor, full-order flux linkage observer, air gap field-oriented vector control.

Efficient operation is a recommended factor in most of industrial applications. In this paper, an indirect matrix converter (IMC) topology is developed and proposed to substitute the classical (AC/DC/AC) three phase converter topologies; where the control strategy is frequently performed with a voltage source inverter (VSI). Large electrolytic capacitors are viewed as hazardous due to their short lifetime compared to ordinary capacitors and power switches, as well as their contribution to the total bulk and weight of the converter. Matrix converters may be the answer to getting rid of the capacitor, shrinking the converter, and improving its efficiency (MC). These advantages are offset by the fact that the (MC) calls for a tricky switching technique based on pulse width modulation, which is prone to commutation failure. The direct frequency conversion using the indirect matrix converter (IMC) with many advantages has appeared as an alternative to these conventional voltage inverters. This study investigates a field-oriented control (FOC) scheme for indirect matrix converter fed triple star induction motor (TSIM). After building the proposed IMC converter topology, an adequate field-oriented control strategy-based space vector modulation (SVM) is proposed and adapted for the control of the triple star induction motor. The FOC technique guarantees flux and torque decoupling while ensuring good operation performance as required in many industrial applications. The obtained numerical simulation results show and confirm the effectiveness of this control scheme.

The objective of this paper is to control the speed of Permanent Magnet Synchronous Motor (PMSM) over wide range of speed by consuming minimum time and low cost. Therefore, comparative performance analysis of PMSM on basis of speed regulation has been done in this study. Comparison of two control strategies i.e. Field oriented control (FOC) without sensor less Model Reference Adaptive System (MRAS) and FOC with sensor less MRAS has been carried out. Sensor less speed control of PMSM is achieved by using estimated speed deviation as feedback signal for the PI controller. Performance of the both control strategies has been evaluated in in MATLAB Simulink software. Simulation studies show the response of PMSM speed during various conditions of load and speed variations. Obtained results reveal that the proposed MRAS technique can effectively estimate the speed of rotor with high exactness and torque response is significantly quick as compared to the system without MRAS control system.

Brushless DC motors are most utilized in areas of aerospace and electric vehicles. They offer great efficiency, compact size, and superior power density. However, the BLDC motor’s torque output ripples provide significant challenges. Torque ripple causes undesirable vibrations, acoustic noise, and reduced performance. The main problem addressed in this article is minimizing torque ripple while achieving precise speed control. The proposed solution to the problem stated here is the Field-Oriented Control (FOC)-based speed control strategy. FOC enables smooth torque production and improved dynamic performance as opposed to typical trapezoidal control methods. The paper involved mathematical modeling of the BLDC motor using Clarke-Park transformations. Space Vector Pulse Width Modulation (SVPWM) is utilized to produce pulses to excite the stator coil. The FOC algorithm was executed in MATLAB/Simulink, and the system has been tested for differing load conditions. Important parameters, such as speed and current response, were analyzed. The ripple percentage of the torque output was compared against the IEEE std. 1812-2023 to prove the effectiveness of the FOC control loop. The results displayed that the FOC system significantly reduced ripple in torque output and thus improved the efficacy of the motor. In conclusion, the FOC strategy proved to be highly effective. It outperformed the six-step commutation strategy with respect to the torque ripple reduction and overall performance. Hence, proving the value of this method of control in applications like electric vehicles.

This paper proposes a rotor orientation control strategy on the large proportion of gyroscopic precession of a linear arc-shaped induction motor with multiple stators, applied to maglev bearings. A physical model of the rotor, considering gravitation, is established via analysis based on rotor dynamics: the kinematic model of the rotor, which is installed vertically, can be simplified as rigid body fixed-point rotation. To complete the dynamic formula, the equivalent circuit of a linear arc-shaped induction motor is transformed into dq0 model by Park transformation, in which the decoupling control of the tangential force and the normal force is determined. Moreover, to realize the control strategy combined air-gap cross feedback with damping method, parameter identification, including no-load test and locked rotor test, is modefied. Therefore, the control strategy, aiming at controlling the speed and guaranteeing the rotor rotating vertically around its axis simultaneously, by adjusting the current of the four stators, can be proved by simulation and experimental platform.

The main feature of an interior permanent magnet synchronous motor (IPMSM) is the reluctance torque, which increases the difficulty of regulating the motor current and torque. This is because the inductance of the stator across the air gap is not equal and vice versa in the surface-mounted PMSM. Thus, the field-oriented control (FOC) strategies of surface-mounted type is greatly desirable to the IPMSM. In this paper, some contributions of the FOC strategy are proposed. The primary objective is to achieve a high dynamic performance of the IPMSM in the region of flux-weakening under sudden torque turbulence and velocity fluctuation. The concentration of the proposed strategy is on the cost function of the parameter optimization, which is optimized based on a genetic algorithm to obtain parameters that will contribute to further driving stability in this region. Meanwhile, the improvement includes adjusting the saturation limits for the outer control loops to cancel the wave overshoots. Finally, the results of simulation and experimentation have fully verified the proposed approach. When compared to the classical strategy, the proposed algorithms can help decrease the settling time and the overshoot in both velocity and current.

Due to significant interaction dynamics and time delays in multivariable processes, designing a well-tuned PI controller is always challenging. When tuning multi-loop PI controllers, effective open-loop transfer function should be used instead of the diagonal transfer function element. The complexity of the effective open-loop transfer function (EOTF) increase rapidly for high-dimensional multivariable processes. Therefore, in this manuscript, it is proposed to use equivalent transfer functions (ETFs) under perfect control approximation. Subsequently, a dead-time compensation (DTC) scheme is used for ETFs and PI controllers are tuned. DTC can facilitate eliminating the impact due to time delay from the multivariable process, making the task of tuning PI controllers relatively less complex. The proposed multi-loop control topology minimizes the controller effort, and a good controller design for a multivariable process can be achieved. The PI controller parameters for dead-time compensated ETFs are calculated using simple IMC PI tuning rules, where the filter factor is taken based on the paired element relative gain value. To examine the effectiveness of the proposed controller tuning approach, the proposed control strategy was applied to a wide range of multivariable processes. Compared to state-of-the-art control strategies, the proposed control strategy provides superior closed-loop performance indices, even when there is a significant plant-model mismatch.