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The rapid adoption of electric vehicles (EVs) has driven the industry to develop advanced traction systems for improved performance and dependability. Such criteria are determined mainly by the magnetic materials used in brushless DC or AC motor commonly used in EV traction systems. More complex motor designs, such as those with two rotors or two stators, have been influenced by improvements in traction systems for transportation tools. The electric motor with multiple rotors or stators has a complex system and lies on parameters that change over time with complex dynamics. Consequently, this motor type needs an intelligent controller to enhance its efficiency and robustness under various drive conditions. Therefore, this article aims to resolve some control complexity for one of these recently used motors. The goal of this is to maximize the efficiency while also increasing motor torque. This motor design is based on a double-stator single-rotor (DSSR) form. The global traction chain is described in this paper by showing the specifications of each part as the interior motor architecture and a suitable AC/DC converter. Examining the best control tool for managing this machine is based on the control topology by using on the field-oriented control (FOC) strategy. A comparison of the effects of three distinct speed controllers, including fuzzy logic, neural networks, and traditional PI controllers, was used to support the FOC architecture. The global traction system architecture and its corresponding control scheme were established on the MATLAB/Simulink platform, and all results were depicted to compare the diverse architectures. At the end of this study, the given results and their corresponding discussions show each control solution's benefits and drawbacks and prove the importance of choosing the appropriate control system for the DSSR motor on the battery state of charge and then on the vehicle autonomy. [ABSTRACT FROM AUTHOR]

Constant switching frequency pulse width modulation (PWM) schemes introduce harmonics in the inverter's output voltage and current which are concentrated at frequencies close to the switching frequency and its multiples. This peaking in the current and voltage harmonic spectrum results in vibration and acoustic noise in AC motor drives. One way to alleviate these problems is by spreading the harmonic spectrum and reducing the magnitude of dominant harmonic components using variable switching frequency schemes. The key objective of this paper is to introduce a novel trapezoidal variation based variable frequency PWM switching strategy to spread out the harmonic spectrum, with reduced current THD even during no-load low-speed operation. This paper also proposes a modified switched DC cell inverter to achieve DC voltage control to enhance the THD reduction. The presented strategy achieves a maximum of 42.2 % reduction in low-speed THD compared to linear sub-cycle period variable frequency PWM, a 46 % reduction in dominant harmonics compared to conventional space vector PWM, and a dispersion index of 1.61, demonstrating its competency as a promising variable switching frequency scheme. The suggested techniques are simulated using MATLAB/Simulink on a vector-controlled Permanent Magnet Synchronous Motor (PMSM) drive and are validated experimentally on a 1.07 kW PMSM drive with a WAVECT-FPGA controller. [ABSTRACT FROM AUTHOR]

A novel pulse width modulation (PWM) overmodulation technique based on splitting variable modulating waveform is proposed in this paper. It aims to solve the disadvantages of complex and difficult application of the existing space vector pulse width modulation (SVPWM) overmodulation algorithm and offer a simpler implementation for overmodulation than classic SVPWM techniques. When the modulation index M is within the linear modulation range [0, 1], the modulating waveform is a sinusoidal wave. With the M is increasing within [1, 4/π], the modulating waveform area expands continuously until it becomes a square wave. The PWM output voltage of the vector control system is implemented by using triangle carrier-based sampling pulse width modulation. Furthermore, digital low-pass filters are used in the d-axis current and q-axis voltage of the system, in order to eliminate the negative influence of the PWM low-order harmonics on the proportion integration control in the overmodulation range. The control software is modified and improved to overcome the shortage of slow response speed. The basic logic of the software is to close the filtering process once the load or speed instructions changes and turn on the filtering process when the transient process ends. The contradiction between the filtering and dynamic responses is thus eliminated by using the basic logic. Compared with the SVPWM working in linear region, the constant torque speed regulating range of the AC motor has an improvement of 10% based on the proposed technique. Simulated and experimental results indicate the good effectiveness and feasibility of this technique. [ABSTRACT FROM AUTHOR]

The cylinder head assembly from a GDI engine was separated to build a GDI fuel injection system capable of controlling the rail pressure and fuel injection levels. The GDI fuel injection system is driven by a three-phase AC motor with a direct connection between the camshaft and the motor. The operating conditions of the GDI fuel injection system are equivalent to those of actual engine driving. The AC motor drives the GDI high-pressure fuel pump by rotating the engine camshaft. In the GDI high-pressure fuel pump (HPFP), fuel is pressurized on the upward stroke of the plunger and pumped to the fuel rail. Fuel rail pressure (FRP) control is possible by controlling the opening/closing timing of the HPFP's pressure control valve (PCV), the fuel injection duration and the camshaft speed. In order to calculate the fuel injection rate characteristics of the GDI injector statistically under fixed conditions of the camshaft speed, FRP, and injection duration, the measurements of the fuel injection rate were repeated at regular time intervals. To calculate the variation of the fuel injection rate, the S/N (signal-to-noise) ratio, which is the average FRP divided by the FRP standard deviation, was calculated. A fuel injection rate was obtained under 88 experimental conditions combining the three conditions of the HPFP's PCV opening/closing timing, fuel injection duration, and camshaft rotational speed. The smaller S/N ratio shows the larger FRP variation. Also, it was identified that the S/N ratio is related to the variation of the fuel injection rate. [ABSTRACT FROM AUTHOR]

An experimental system was developed to evaluate the fuel injection parts of a gasoline direct injection engine. An AC motor and an inverter were used to rotate the camshaft in the engine cylinder head. A single plunger high-pressure fuel pump (HPFP) driven by a square cam at the end of the camshaft was used in the gasoline direct injection engine. The rotation position of the square cam was measured by a rotary encoder. The developed system allows control of the camshaft rotation speed, the HPFP pressure control valve (PCV) opening and closing timing, and the fuel injection duration, which are three important factors affecting the fuel rail pressure (FRP). It is confirmed that the fuel rail pressure can be made to vary wit different combinations of these three factors. By using the experimental system developed in this study, the fuel rail pressure can be effectively controlled in the range of 3 MPa to 20 MPa. The most influential factor for control of the fuel rail pressure was the HPFP PCV opening and closing timings. With the proposed using the experimental system, the rail pressure, fuel rail pressure wave characteristics, and the injector drive characteristics can all be assessed under various fuel injection conditions. [ABSTRACT FROM AUTHOR]

A hysteresis current controller (HCC) is commonly used in high-performance AC motor drives to control the current directly. Recently, the predictive current controller (PCC) is also used as an alternative to the classical current controller for speed and torque regulation of induction motor (IM) drives. However, PCC has drawbacks of large flux and torque ripples, large total harmonic distortions (THDs) in current and voltage and dependency on parameters. This paper proposes current control with artificial neural network (ANN) for a field-oriented controlled induction motor (FOCIM) drive. The ANN has input current error between the reference and the measured stator currents. The output function of neuron is a hyperbolic tan (or tan-sigmoid) function to apply error Levenberg–Marquardt (L–M) back propagation as learning rule because of its fast convergence. The proposed method is based on a new approach in which hysteresis band is replaced by ANN comparator to improve the performance of the FOCIM drive. It minimizes torque ripples, flux ripples, voltage and current THDs over the existing HCC and PCC methods. The superiority of the proposed method compared to existing methods is established by simulation and experimental results. [ABSTRACT FROM AUTHOR]

The overmodulation operation of a three-phase inverter can enhance the output torque capacity of the AC motors. In this case, the enhancement varies depending on the overmodulation schemes applied for the overmodulation operation. Steady-state overmodulation schemes are usually employed to give the unit voltage gain up to the six-step mode of an inverter. However, these schemes lead to a slow transient response of the output torque and require a complex algorithm for implementation. On the other hand, dynamic overmodulation schemes can achieve a rapid transient response of the output torque and are simple to implement. However, inverters using these schemes cannot work up to the six-step mode since the voltage gain of the inverter is less than one in the overmodulation region. In this paper, a technique is proposed that can increase the DC voltage utilization of an inverter by improving the voltage gain in dynamic overmodulation operation. An inverter with dynamic overmodulation using the proposed technique can work up to a six-step mode. Hence, AC motors can obtain enhanced torque capacity during flux-weakening operation. Consequently, an improved transient torque response can be achieved in the high-speed region. From simulation and experimental results, it was validated that the proposed technique can be used for dynamic overmodulation operation for not only the continuous PWM but also the DPWMs (discontinuous pulse width modulations). [ABSTRACT FROM AUTHOR]

This paper deals with quality comparison of current sensing of the two different power traces arrangements and two types of the DC-link shunt resistors. Investigation of current sensing quality was carried out using the two types of high current power stages, which have different power traces arrangement. Both power stages are designed for low-voltage three-phase AC motor drives, mainly in automotive application area. The first power stage contains mixed-signal microcontroller with integrated gate drive unit and analog circuits. The second power stage was designed to accommodate any type of microcontroller connected to the board via connector. The power traces arrangement is analyzed, and the influence on DC-link current sensing is discussed. [ABSTRACT FROM AUTHOR]

The paper describes manufacturing and testing of HTS double racetrack coils intended for use in stator windings of small-size motor, proposed for electric unmanned air vehicle (UAV). The level of AC losses of the armature characterizes required flow of liquid hydrogen (LH) coolant. Thus, it affects overall configuration of the UAV by LH-tank mass and volume. On the other side, motor will be driven by AC motor controller (inverter), so the armature currents will not be pure sinusoidal, and formed by pulse width modulation (PWM). In this work, the manufactured coil is tested on meander-form AC current with frequencies up to 200 Hz with and without solid ferromagnetic core. In addition, losses on PWM currents were also determined on a specific H-bridge to ensure functionality of HTS coils in such conditions. [ABSTRACT FROM AUTHOR]

Influence of leading ultrasonic vibrations on the process forces in the friction stir lap welding of AA 6061-T6 with and without ultrasonic vibrations is investigated at varied welding speeds. The axial force, traverse force, and tool torque in the processes are determined by adopting a recently developed method that uses electrical signals of the servo motors and main spindle AC motor of the friction stir welding machine during the welding process. It is found that the exerted ultrasonic vibrations decrease the welding forces without compromising the mechanical properties of welds. The effect of ultrasonic vibrations on traverse force is more pronounced than that on the tool torque and axial force. Force measurements at different welding speeds indicated that the axial force and traverse force varied significantly with travel speed of tool. Not much difference is found in the tool torque variation. With ultrasonic vibrations, the reduction in welding force in different directions is affected differently by welding speed. The ultrasonic effect on welding forces is found to be governed by the travel speeds of both the tool and workpiece. [ABSTRACT FROM AUTHOR]

With the development of renewable energy, grid-connected inverter technology has become an important research area. When compared with traditional silicon IGBT power devices, the silicon carbide (SiC) MOSFET shows obvious advantages in terms of its high-power density, low power loss and high-efficiency power supply system. It is suggested that this technology is highly suitable for three-phase AC motors, renewable energy vehicles, aerospace and military power supplies, etc. This paper focuses on the SiC MOSFET behaviors that concern the parasitic component influence throughout the whole working process, which is based on a three-phase grid-connected inverter. A high-speed model of power switch devices is built and theoretically analyzed. Then the power loss is determined through experimental validation. [ABSTRACT FROM AUTHOR]

In this paper, an optimum design for a three-phase line-start synchronous reluctance motor (LS-SynRM) with respect to efficiency, maximum torque, and starting torque is proposed. The design variables, objective functions, and constraints are selected for this optimum design, which is divided into two steps. Step I maximizes the rated efficiency, while maintaining balanced operation and minimizing the stator copper loss. Step II calculates the precise starting torque using finite element analysis (FEA). The validity of the optimum design is verified by comparing the efficiency, maximum torque, and starting torque characteristics of the time-step FEA with experimental results. [ABSTRACT FROM AUTHOR]

A dimensionality reduction load torque observed is designed to provide compensation control for the motor with the observation value of load torque converted over for the problem that load disturbance decreases the control precision of servo system. A three-loop mathematical model is established for the servo control system. Use of two-/three-order optimal model theory contributed to the derivation of the tuning formula for three-loop control parameters. A simulation model is established for the space vector control of AC servo system. The simulation experiment validates that the tuned three-loop parameter provides the system with good dynamic performance. An experiment platform is built. The load sudden change experiment of the motor demonstrates the feasibility that torque compensation control improves the control precision of servo system in the presence of load disturbance. [ABSTRACT FROM AUTHOR]

Permanent magnet synchronous motors (PMSMs) have higher torque and superior output power per volume than other types of AC motors. They are commonly used for applications that require a large output power and a wide range of speed. For precise control of PMSMs, knowing the accurate position of the rotor is essential, and normally position sensors such as a resolver or an encoder are employed. On the other hand, the position sensors make the driving system expensive and unstable if the attached sensor malfunctions. Therefore, sensorless algorithms are widely researched nowadays, to reduce the cost and cope with sensor failure. This paper proposes a sensorless algorithm that can be applied to a wide range of speed. The proposed method features a robust operation at low-speed as well as high-speed ranges by employing a gain adjustment scheme and intermittent voltage pulse injection method. In the proposed scheme the position estimation gain is tuned by a closed loop manner to have stable operation in tough driving environment. The proposed algorithm is fully verified by various experiments done with a 1 kW outer rotor-type PMSM. [ABSTRACT FROM AUTHOR]

With the help of high-speed photography, the microscopic laws of alkali-surfactant-polymer (ASP) droplet deformation under high voltage alternating current (AC) electric field were studied. The influences of AC electric field intensity and frequency were investigated in detail. Moreover, the synergistic effect of alkali-surfactant-polymer on drop deformation was reported. Experimental results demonstrate that there is a power law relationship between the deformation of alkali-surfactant-polymer droplet and the electric field strength. And it could be inferred that ASP interactions should be responsible for the complex relationship between ASP droplet deformation and the AC electric field frequency. [ABSTRACT FROM AUTHOR]

This Mixed Signal Letter presents a proposal of four-quadrant linear-assisted DC/DC voltage regulator. In this topology, a class-AB linear voltage amplifier assists a four-quadrant switching DC/DC converter in order to obtain a compact circuit with advantages of both alternatives; i.e., high efficiency, inherent in switching converters, and low output ripple and fast reaction to the load changes that are characteristics of linear regulators. In order to reduce the power dissipation in the linear regulator, it is considered as an assisting circuit for providing just a small fraction of the total load current. Furthermore, this stage provides the required clock signal for the switching counterpart, obtaining a compact topology thanks to the reduction of the complexity in the design of the control scheme for the switching converter. In fact, the proposed topology can be addressed to on-chip practical implementations, since no output capacitors are required. This last advantage provides the possibility of obtaining good-performance power-supply modulators for envelope tracking techniques in power amplifiers. The implementation and results indicate that the proposed four-quadrant linear-assisted DC/DC regulator can achieve a notably compacting and higher performance, while consuming less power in comparison to linear alternatives. [ABSTRACT FROM AUTHOR]

PI controllers are one of the most widely used controllers in industrial control systems due to their simple algorithms and stability. The parameters Kp and Ki, determine the performance of the system response. The response is expected to improve by increasing the gain of the PI controller. However, too large a gain will accelerate the speed response and cause vibrations, which is not what is expected. This paper proposes a way to suppress vibrations by detecting the vibration frequency and extracting the vibration signal as a compensation to the speed feedback. Additionally, in order to improve its disturbance rejection ability, a low-order disturbance observer is proposed. This paper also explains the operation principle of the proposed method by analyzing the transfer function and it describes the design of the controller parameters in detail. Simulation and experimental results are provided to verify the merits of the proposed method. These results also show the good performance of the proposed method. It has a rapid response and suppresses vibrations. [ABSTRACT FROM AUTHOR]

This study presents an electromagnetic model for predicting shaft voltages in a 2-pole field-excited synchronous generator. After the first observations on shaft voltages were made more than a century ago, extensive work has been conducted on eliminating, mitigating, and integrating the aforementioned phenomena. Given that emphasis has been placed on modeling shaft- and bearing-induced voltages in AC motors driven by variable frequency drives, similar efforts toward a model that is dedicated to generators are insubstantial. This work endeavors to improve current physical interpretation and prediction methods for shaft-induced voltages in generators through semi-analytical derivation. Aside from the experimental validation of the model, investigations regarding the behavior of shaft voltages under varying machine complexities and operating conditions clarify previous uncertainties regarding these phenomena. The performance of the numerical method is also assessed for application in eccentricity fault diagnosis. [ABSTRACT FROM AUTHOR]