Single-phase Machine Research Articles

Design and Implementation of a Low-Cost and Low-Power Converter to Drive a Single-Phase Motor

This research introduces a cost-effective converter for single-phase machines, aiming to enhance efficiency and reduce energy consumption in retrofit applications. Single-phase motors commonly found in household appliances often suffer from low efficiency, resulting in wasted energy. To tackle this problem, a dedicated converter was proposed to replace the existing capacitors and improve the motor performance. This study presents a proof of concept for retrofit applications, discussing the converter design methodology and prototype evaluation. Additionally, a cost analysis comparing single-phase and three-phase motors is included. It aims to demonstrate the long-term cost savings and improved energy efficiency of the proposed converter. The findings highlight the converter’s potential as a promising solution for enhancing energy efficiency and decreasing costs in single-phase motor applications.

Cascading Deep Learning Approach for Identifying Facial Expression YOLO Method

Face detection is one of the biggest tasks to find things. Identification is usually the first stage of facial recognition. and identity verification. In recent years, in-depth learning algorithms have changed dramatically in object acquisition. These algorithms can usually be divided into two groups, namely two-phase machines like Faster R-CNN or single-phase machines like YOLO. While YOLO and its variants are less accurate than the two-phase detection systems, they outperform other components with wider genes. When faced with standard-sized objects, YOLO works well, but can't get smaller objects. A face recognition system that uses AI (Artificial Intelligence) separates or verifies a person's identity by analyzing their faces. In this project, a single neural network predicts binding boxes and class opportunities directly from the full images in a single test.

A Novel Approach to Transverse Flux Machine Construction

The article presents a concept for a new design of the well-known Transverse Flux Machine (TFM) made with the use of a flat core used in classical electrical machines. The proposed design was first analytically verified and was subsequently verified using the finite element method, which fully corroborated the results. The simulations show that a set of three single-phase TFM machines with slotted flat rotor yokes generates a torque over three times greater than that of an induction motor and twice as large as Fractional Slot Concentrated Winding—Permanent Magnet Synchronous Machines (FSCW-PMSM). The performed comparative calculations confirmed that the torque generated by machines operating on principles similar to TFM can generate a torque much greater than those currently in common use.

Analysis and Comparative Evaluation of Multi Stack and Novel Single Stack Polyphase Transverse Flux Machines

Transverse flux machines (TFMs) originally have heteropolar arrangement of permanent magnets (PMs) on the rotor and a ring winding on the stator. These conventional TFMs are single stack single phase machines. To realize a multi stack polyphase machine, multiple single phase TFMs have to be stacked together. As an alternative to conventional multi stack polyphase TFM (T 0), a single stack polyphase TFM (T 1) is proposed in this paper. The proposed single stack polyphase TFM has homopolar arrangement of PMs on the rotor and a polyphase winding on the stator. Both the machines (T 0 and T 1) are analyzed using magnetic equivalent circuit (MEC) and finite element analysis (FEA). The machines are compared on the basis of their structure, material requirement, parameters and performance. The outcome of the comparative study of the TFM topologies under consideration, leads to correlation between structure of the TFMs and their performance. In this work benefits and limiting factors of the proposed topology over the conventional topology are discussed. Prototype of the proposed machine is developed and experimental validation of the proposal is presented.

Sensorless Control System for a Single-Phase DC-Excited Flux-Switching Machine With Self-Starting Capability

Single-phase dc-excited flux-switching machine (DCFSM) exhibits low manufacturing cost and rugged structure. This type of machine has better efficiency and torque density than single-phase induction machine and universal machine. In addition, single-phase DCFSM can generate lower torque ripple than other types of single-phase machines, e.g. switch reluctance machine and brushless DC machine. These advantages make it suitable for low-cost variable speed applications. However, single-phase DCFSMs requires accurate position feedback from a position sensor to generate smooth torque. The position sensor such as an encoder is not permitted in the low-cost applications due to its high cost. To eliminate the position sensor, this paper presents a novel sensorless control scheme for single-phase DCFSMs. Rotor position is estimated with the position-dependent armature current ripple induced by injecting high-frequency square-wave voltage to the field winding at standstill and low speeds. At medium and high speeds, armature mutual flux linkage is calculated and used to estimate the rotor position. A seamless transition between these two methods is achieve by mixing the calculated position error signals as the input for a single position estimator. The experimental results show that with the proposed scheme, the single-phase DCFSM can accelerate from standstill to the rated speed with 50% load, and to the maximum speed with 25% load, respectively.

COMPARATIVE ANALYSIS OF TWO HIGH-SPEED SINGLE-PHASE ELECTRICAL MACHINES WITH PERMANENT MAGNETS ON THE STATOR

Purpose: Single-phase machines with permanent magnets on the rotor are widely used in a variety of applications of a low rated power. When these machines are applied in high-speed applications, a retaining ring on the rotor core must be often used. However, it makes the assembly more complex and the high-speed machines become more expensive. On the other hand, machines with magnets on the stator still can be a valuable alternative due to their simple and reliable rotor design. In this paper the comparative study of performances of two single-phase electrical machines with magnets on the stator (flux reversal electrical machine and hybrid switched reluctance machine) is presented. The following performances have been compared: efficiency, weight, active materials cost, value of rated current of switches of the frequency converter. Methodology: Calculation of electrical machines performances using solving two-dimension boundary magnetostatics problems. Results. The theoretical comparison of the flux reversal electrical machine and the hybrid switched reluctance machine has been carried out; the comparison on specific torque and efficiency of the two aforementioned machines have been obtained. The flux reversal machine has a significantly higher efficiency and a fewer weight. In addition, it has a lower value of rated current. On the contrary, the cost of active materials of the hybrid switched reluctance one is much less. Originality: The presented results can assist in selecting the best design alternative of electrical machines in the following applications: electrical blowers, household appliances, fans, pumps and compressors of a low rated power etc. Practical value: The comparisons results of the flux reversal electrical machine and the hybrid switched reluctance machine has been obtained for the first time.

Impact of Number of Phases on Electromagnetic Torque Characteristics of Transverse Flux Permanent Magnet Machines

This paper presents an investigation on the influences of number of phases of Transverse Flux Permanent Magnet (TFPM) machines on the characteristics of developed electromagnetic torque. Electromagnetic torque is expressed in terms of the Fourier series of phase currents and internal voltages. After some algebraic and trigonometric calculations, a general equation is obtained that establishes a relationship between the electromagnetic torque ripples, number of phases and harmonic contents of both internal voltages and phase currents. This result is significant when it is required to design a few specific number of identical single-phase TFPM machines which finally they will be assembled such that to build a multi-phase machine with a minimum torque ripple. The design parameters of a case study Claw Pole TFPM machine are introduced with some details and a few FE based simulation results are given as the validations of the analytical approach of the present paper. The simulation results show clearly the impact of each harmonic of the internal voltages and phase currents on the torque ripple for various numbers of phases leading the designer to find out which number of single-phase machine combinations is the optimum one regarding the torque ripple.

Recognizing Past IAS Engineers and Their Contributions to Motors and Drives [History

Electrical machines and drives have been long-standing and significant areas in the application of the electrical engineering arts. According to the "History" column in commemoration of the IEEE Industry Applications Society's (IAS's) 50th anniversary in 2017 [1], the present IAS Electric Machines Committee (EMC) traces its roots to the Single-Phase and Fractional-Horsepower Machines Subcommittee of the identically named Electric Machines Committee that was under the American Institute of Electrical Engineers (AIEE) in 1947. In 1963, this subcommittee became part of the Rotating Machinery Committee of the combined AIEE and IEEE Power Engineering Society, now the IEEE Power & Energy Society (PES).

Optimal Design of a Novel Three-Phase High-Speed Flux Reversal Machine

A single-phase flux reversal machine (FRM) has many advantages in high-speed applications because of its simple and reliable rotor structure without magnets or winding, simple and cheap concentrated stator windings, high efficiency, and power density. However, the major problem of single-phase motors is the high torque ripple, which shortens their lifetime and causes noise and vibrations, not only in the machine, but also in the mechanisms coupled therewith. This paper presents a novel three-phase machine consisting of three single-phase machines, having a common shaft aiming to reduce the torque ripple and to improve motor behavior. In this paper, the mathematical model of the single-phase flux reversal motor, as well as the conversion procedure of the single-phase motor parameters to the three-phase ones, is considered. Furthermore, an optimization procedure of the motor and choosing the optimization objectives are done. The finite element two-dimensional (2D) method is used to simulate the machine and to show the results.

Vector Control of a Single-Phase Induction Machine with Scott-T Connection in the Stator and Estimation of Velocity with Sliding Mode Observer

This paper shows a high-performance sensorless driver for an induction machine with a Scott-T connection in the stator windings.This connection is used to transform a single-phase machine into a three-phase only by changing the winding configuration, increasing efficiencyand minimizing the cost impact. This type of solution can be used as an alternative to the use of highperformance drivers controlling single-phaseinduction machines. The motor model using the Scott-T connection is developed and the experimental results of a vector control approach by fieldorientation are shown. A sliding mode observer is also developed for estimating the speed of the machine tested.

Low voltage ride through capability of single-phase induction machines

Stochastically occurring voltage sags as they may occur with low quality of the power supply may significantly affect the operational behavior of single-phase starting and running capacitor assisted induction machines. In contrast to three-phase machines which are still subjected to a rotating field, even during voltage sags, the single-phase machines are subjected to an alternating field that can be decomposed into two rotating fields, a positive and a negative sequence one. Thus, the behavior of these machines when submitted to voltage sags cannot be directly derived from the established understanding of the low voltage ride through capability of three-phase machines. The effects of such voltage sags on a single-phase machine’s transient behavior not only depend on the electric capacitive circuit and the machine’s electromagnetic design, but strongly on the moment the short circuit occurs, its duration, and the load of the machine. In this work, we analyze the robustness of such a system towards an extremely voltage sag, in particular a terminal short circuit. To this aim, experimentally validated transient FE computations are used.

Design of a High Starting Torque Single-Phase DC-Excited Flux Switching Machine

Because single-phase dc-excited flux switching machines (DCFSMs) consist of only copper windings and iron cores, they have great potential in low-cost and high-speed applications, such as home appliances. However, similar to other types of single-phase ac machines, single-phase DCFSMs have insufficient initial torque at some rotor positions. A novel single-phase, eight-slot, four-pole DCFSM design is presented in this paper. The key feature of this design is the enhancement of reluctance torque at positions where the machine cannot deliver sufficient initial torque output. This is accomplished by modifying the outline of a section of the rotor. Consequently, the machine has a two-layer rotor structure along the axial direction. The proposed design is validated experimentally using a prototype. The results show that the machine can start from any rotor positions with initial torque higher than 50% of the rated output torque.

A single-phase axially-magnetized permanent-magnet oscillating machine for miniature aerospace power sources

A single-phase axially-magnetized permanent-magnet (PM) oscillating machine which can be integrated with a free-piston Stirling engine to generate electric power, is investigated for miniature aerospace power sources. Machine structure, operating principle and detent force characteristic are elaborately studied. With the sinusoidal speed characteristic of the mover considered, the proposed machine is designed by 2D finite-element analysis (FEA), and some main structural parameters such as air gap diameter, dimensions of PMs, pole pitches of both stator and mover, and the pole-pitch combinations, etc., are optimized to improve both the power density and force capability. Compared with the three-phase PM linear machines, the proposed single-phase machine features less PM use, simple control and low controller cost. The power density of the proposed machine is higher than that of the three-phase radially-magnetized PM linear machine, but lower than the three-phase axially-magnetized PM linear machine.

Mathematical simulation of a high-speed single-phase machine with alternating current direction

A new design of a single-phase flux reversal machine (FRM) and a procedure of mathematical simulation of the FRM are described in this article. Technical features of the FRM (such as efficiency, specific power, and specific torque) that are close to those of synchronous motors with magnets on the rotor have greater reliability for high speed applications. The main advantages of an FRM involve the absence of permanent magnets or electric conductors on a rotating rotor and their being positioned on a stator. The new design of a single-phase FRM consists of a rotor with four teeth and a stator with four teeth and a magnetic system. The magnetic system on the stator teeth surface has two magnets on each stator tooth and generates two magnetic poles on each one. The adjacent poles on the adjacent teeth of stator are similar. The total angular size of new design is slightly less than the perimeter of the circle. Therefore, the stator surface is much better used (unlike the prototype), which results in an increase in the specific power and power efficiency, as well as a decrease in the cost of the FRM. A method for mathematical simulation of an FRM that is based upon solving magnetostatic problems with common geometry is proposed. Different positions of the rotor are simulated by joining boundary conditions. The method allows one to determine the electric losses in steel and magnets in postprocessing.

Enhanced Power Generation From Two-Winding Single-Phase SEIG Using LMDT-Based Decoupled Voltage and Frequency Control

This paper proposes a leaky minimal disturbance theory (LMDT)-based decoupled control of voltage and frequency for two-winding single-phase self-excited induction generators (SEIGs) for enhanced power generation and power quality improvement. Single-phase two-winding SEIGs are normally designed with 33% derated capacity in comparison to three-phase SEIGs of the same frame size. Using single-point operation performed by the proposed decoupled voltage and frequency controller (DVFC), the two-winding single-phase machine can generate enhanced power output, nearly 33% higher than its normal capacity. It is equal to the power generated by a three-phase machine with the same frame size. The DVFC consists of a voltage source converter (VSC) and a closed-loop controlled dump load. A single-phase VSC is used for harmonics and fundamental reactive power compensation for system voltage control and harmonics mitigation. The control of VSC is achieved using an LMDT-based control algorithm. The minimal disturbance theory-based control algorithm is used for potentially fast convergence and fast dynamic response, whereas the leakage factor is added for improving the steady-state performance of the system. The LMDT control-based VSC-battery energy storage system scheme is also implemented for the voltage and frequency control of a single-phase SEIG. Both schemes are implemented in real time using a digital signal processor.

Wound Rotor Machine With Single-Phase Stator and Three-Phase Rotor Windings Controlled by Isolated Three-Phase Inverter

This paper proposes a single-phase grid-connected wound rotor machine that has the single-phase stator and three-phase rotor windings. The machine has no auxiliary winding or capacitor unlike conventional single-phase machines. Nevertheless, it can operate in all four quadrants of the torque–speed plane with a three-phase inverter. For adjustable speed drives, an isolated three-phase inverter is applied to the rotor windings while the stator winding is directly connected to a single-phase source. The grid filter and rectifier of the conventional system are eliminated and the rotor-side slip rings can be also removed by the inverter integration. So the overall structure of the proposed drive system is simple and cost effective. In this paper, the proposed machine is modeled into a modified d – q model considering the absence of q -axis stator coil. Its characteristics are analyzed and vector control methods of the grid power factor, dc-link voltage, and speed are proposed. For more efficient control, the optimal rotor current set is calculated from the minimum copper loss condition. The system has wider operating areas than other single-phase drive systems. The feasibility of the proposed system is verified by experiments.

3-D FEM Calculation of Electromagnetic Properties of Single-Phase Induction Machines

In comparison with three-phase induction machines, modern single-phase induction machines normally have skewed rotors, but show an elliptic magnetic field during start-up. In order to properly model the start-up of such a machine, this three-dimensional (3-D) characteristic has to be accounted for. This leads to the application of the 3-D finite-element method. This paper will introduce a new approach to model and analyze the start-up of such a single-phase machine, with the aim of higher computational efficiency. Furthermore, this paper will discuss how symmetries, both in the circumferential direction and along the motor shaft, can be exploited despite the skewing. This is achieved through transforming (rotating) the cutting plane, doubling the skewing angle, and increasing the rotor conductor conductivity. The analysis is carried out on a small two-pole 100-W machine used for household appliances. The theoretical results are compared with experimental results for six rotors; each with a different skewing angle.

Comparison of Low-Cost Single-Phase Wound-Field Switched-Flux Machines

This paper presents a comparative study of two types of low-cost single-phase wound-field switched-flux machines with dc field and ac armature windings having the same coil-pitch of 2 slot-pitches and having different coil-pitches of 1 and 3 slot-pitches, respectively. Both can share the same stator lamination, but the latter can have shorter end windings and lower iron loss for the 12-slot/6-pole configuration. The performance, including back electromotive force, cogging torque, and static torque, of both machines are analyzed and compared by 2-D finite-element analysis and validated by experiments on the prototype machines.

Cogging Torque Optimization of Flux-Switching Transverse Flux Permanent Magnet Machine

In this paper, cogging torque characteristics in both single-phase and three-phase flux switching transverse flux permanent magnet machines (FS-TFPMM) are analyzed by 3-D finite element method (FEM). It is found that the cogging torque of the FS-TFPMM is significantly influenced by the ratios of stator and rotor core circumferential widths to pole pitch, $k_{s}$ and $k_{r}$ . When $k_{r}>1-k_{s}$ , the cogging torque waveform has additional two zero-crossing points, whilst its amplitude is significantly reduced. The optimal ratios of $k_{s}$ and $k_{r}$ are selected to reduce the cogging torque and to maximize the permanent magnet flux linkage. A 380 W three-phase prototype is designed, manufactured, and tested to verify the optimization.

Vectorial Formalism of Polyphase Synchronous Machine With Permanents Magnets

Abstract- This paper presents a mathematical model that transforms the real machine to fictitious machines and our goal is to simulate these and see the behavior of these machines in load. The polyphase machines are developed mainly in the field of variable speed drives of high power because increasing the number of phases on the one hand allows to reduce the dimensions of the components in power modulators energy and secondly to improve the operating safety. By a vector approach (vector space), it is possible to find a set of single-phase machine and / or two-phase fictitious equivalent to polyphase synchronous machine. These fictitious machines are coupled electrically and mechanically but decoupled magnetically. This approach leads to introduce the concept of the equivalent machine (multimachine multiconverter system MMS) which aims to analyze systems composed of multiple machines (or multiple converters) in electric drives. A first classification multimachine multiconverter system follows naturally from MMS formalism. We present an example of a pentaphase (polyphase) synchronous machine for a simulation and study the behavior of the machine load. Keywords: Polyphase machines, multimachine concept, vector space, eigenvectors, eigenvalues, pentaphase machine.