Line-start Permanent Magnet Motor Research Articles

Steady-State Analysis of a Canned Line-Start PM Motor

This paper describes the development of an analytical method for predicting the steady-state response of an integrated “pump-motor-containment.” These pumps employ a canned line-start permanent-magnet motor providing synchronous operation and high load efficiencies. The steady-state performance of the pump motor is assessed under different operating conditions. A laboratory prototype machine is used to validate the model.

Line-Start Permanent-Magnet Motors: Significant Improvements in Starting Torque, Synchronization, and Steady-State Performance

We present a new scheme to improve the starting torque and synchronization capability of line-start permanent-magnet motors based on pole changing winding. Pole changing at start-up neutralizes the magnetic influence of permanent magnets and, therefore, leads to the elimination of braking and pulsating torques, and enhances the starting torque. Our scheme also solves the synchronization problem. We used finite-element analysis to validate the scheme. The simulation results show that the method leads to a high starting torque, good synchronization, and excellent steady-state performance.

Analysis of non-linear effects on starting characteristics of a single-phase line start permanent magnet motor

This paper deals with starting characteristics of a single-phase line start permanent magnet (LSPM) motor considering nonlinear properties of magnetic materials. To take into account nonlinearity of iron core according to operating states, d-and q-axis inductances are calculated by magneto-static FE-analysis for various currents. The calculated dq-axis inductances are used in the equivalent circuit of a single-phase LSPM motor and dynamic performances are analyzed with 4th order Rung-Kutta method. The results are compared with time-step FE-analysis results and the effects of nonlinearity are discussed.

Line start permanent magnet synchronous motors: Challenges and opportunities

Future energy challenges, likewise the environmental crises such as fossil fuel emissions and global warming urge the world to focus on energy saving programs more than ever. An effective way to face these challenges is to improve electric motors efficiency as one of the greatest energy consumption apparatuses in the world. Induction motors constitute, by far, the largest portion of electric motors both in terms of quantity and total power ratings among all electric motors. However, more efficient motor types gradually appear as alternatives. In this paper, line start permanent magnet motors as a powerful candidate with growing market are investigated in some details. The motor opportunities like high efficiency, high power factor and high power density are explored against the challenges associated with this motor including higher cost, extra manufacturing burden and transient and synchronization behaviors. Finally, some concluding comments and remarks are drawn for future research and manufacturing of line start permanent magnet motors.

Analysis of a Three-Phase LSPMM by Numerical Method

Line-start permanent magnet motor (LSPMM) is a very attractive alternative to replace induction motors due to its very high efficiency and constant speed operation with load variations. However, designing this kind of hybrid motor is hard work and requires a good understanding of motor behavior. The calculation of load angle is an important step in motor design and can not be neglected. This paper uses the finite element method to show a simple methodology to calculate the load angle of a three-phase LSPMM combining the dynamic and steady-state simulations. The methodology is used to analyze a three-phase LSPMM.

A Study on the Optimal Rotor Design of LSPM Considering the Starting Torque and Efficiency

This paper presents the optimal rotor design method in a single-phase line-start permanent magnet motor (LSPM) considering the starting torque and efficiency. To consider nonlinear characteristics, the design process is comprised of the FEM and analytical method. During this study, permanent-magnets and cage bars were designed using the magnetic equivalent circuit method and the barriers that control all magnetic flux were designed using the FEM, and the tradeoff of starting torque and efficiency is controlled by weight function in Taguchi method simulation. Finally, the performance of the optimal model is compared with those of conventional models.

A study on the irreversible magnet demagnetization in single-phase line-start permanent magnet motor

The large demagnetizing currents in a single-phase line-start permanent magnet motor are generated by a starting and locked rotor condition. Thus, irreversible magnet demagnetization occurs due to the external demagnetizing field by these currents. In this paper, we present the phenomenon of the irreversible magnet demagnetization using two-dimensional finite-element method (2-D FEM). The nonlinear analysis of a permanent magnet is added to 2-D FEM to consider irreversible demagnetization. As a result, design techniques which are effective in avoiding irreversible demagnetization are proposed.

Influence of Space Harmonics on Starting Performance of a Single-Phase Line Start Permanent-Magnet Motor

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this paper, we investigate the effects of space harmonics of single-phase line start permanent-magnet (LSPM) motors on starting performance. We construct an equivalent electric circuit considering the harmonics for the analysis, in which the magnetostatic field computation is coupled with finite-element modeling. We analyze the starting characteristics by circuit simulation and show that the results compare well with those of time-step finite-element analysis and of experiments. </para>

Design and Analysis of Large Capacity Line-Start Permanent-Magnet Motor

This paper presents a successful design of a large capacity line-start permanent-magnet motor (LSPM), which is developed for industrial fans, pumps and compressors to reduce the energy consumption. It keeps the configuration of induction motors of the same capacity as much as possible due to the limitations of cost and manufacture process. In order to assess the starting capability, two-dimensional dynamic finite element model is employed to analyze the transient performance of both the LSPM and the induction motor of the same capacity. The model is proven to be correct as the predicted result of the induction motor is validated experimentally. By comparing the performance of these two motors, it is shown that the proposed LSPM exhibits higher power factor and efficiency.

단상 유도형 동기 전동기(LSPM)의 특성해석에 관한 연구

Electric motor efficient improvement from home appliance field is important to the effect reducing the energy consumption. But the electric motor design/analysis technology is still insufficient. Specially the electric motor design/analysis technology of satisfying characteristic of both the induction motor and the synchronous motor such as Line start permanent motor. Therefore the electric motor design/analysis technology is urgently demanded reliability. This paper proposes the sing1e-phase line-start permanent magnet motor to develop the motor it with be able to alternate the sing-phase induction motor it is a refrigerator compressor motor. The sing-phase induction motor is analyzed in the steady state. And we have a certification test to compare our single-phase line-start permanent magnet motor with the sing-phase induction motor. In order to improve the performance, the stator of the single-phase line-start permanent magnet motor is same as the stator of the sing-phase induction motor and changes the rotor form and has the permanent magnet. It used the Finite Element Method(FEM) which is widely used with electronic-magnetic field numerical analysis method.

Design of Single-Phase Line-Start Permanent Magnet Motor Using Equivalent Circuit Method

In this research, the design procedure and the design method of a single-phase line-start permanent magnet motor (LSPM) are proposed. In the design procedure, the permanent magnet is designed first and the windings and capacitors are designed later. As well, the points of design of each design parameter are explained. In the design of the single-phase LSPM, the equivalent circuit method is combined with the finite element method (FEM) because it has a shorter analysis time than FEM. The 400 watts single-phase LSPM is designed and manufactured. The characteristics of the manufactured single-phase LSPM are analyzed and experimented. From the analysis result and the experiment result, it is verified that the design procedure and the design method of the single-phase LSPM is valid.

Effect of winding harmonics on the asynchronous torque of a single-phase line-start permanent-magnet motor

This paper presents an analytical method for calculating the effect of winding harmonics on the asynchronous torque of a single-phase line-start permanent-magnet motor. The method is an extension of earlier work, which combines symmetrical-component analysis with d-q-axes theory to model the various components of forward and backward rotating fields. The effect of individual winding harmonics is brought out both theoretically and experimentally by comparing the calculated and measured torque/speed characteristics for a series of six motors with different distributions of turns in both main and auxiliary windings

Design of post-assembly magnetization system of line start permanent-magnet motors using FEM

In this paper, we propose a design procedure and methods for designing the post-assembly magnetization system of a three-phase line start permanent-magnet motor (LSPM). According to the design procedure and the design methods, the post-assembly magnetization system is designed and manufactured. From the experimental results, we verify that the permanent magnet of LSPM is successfully magnetized.

Study in the post-assembly magnetization method of permanent magnet motors

This paper studies two post-assembly magnetization methods for permanent magnet motors. One is stator winding magnetization method (SWMM) for ferrite magnets. The other is magnetizing fixture magnetization method (MFMM) for magnets having large coercive force like NdFeB magnets. They are applied to three types of permanent magnet motors: SPM type of BLDC motor, LSPM type motor and IPM type of BLDC motor. In case of line start permanent magnet motors(LSPM), the eddy current produced in the rotor bars seriously disturbs magnetizing. Therefore, the magnetization processes are analyzed by using the time stepping finite element method. As a result, it is clarified that the SWMM is proper for the SPM type motor using ferrite magnets and the MFMM is proper for the LSPM and IPM type motors using NdFeB magnets.

Line-start permanent-magnet motor: single-phase starting performance analysis

This paper presents a detailed quasi-steady-state approach to different torque components (average and pulsating) for a single-phase capacitor-run permanent-magnet (PM) motor. By employing average electromagnetic torque, and the expected envelope of the pulsating torque, an accurate prediction of starting torque components behavior is made. The quasi-steady-state analysis of the asynchronous performance of the single-phase capacitor-start capacitor-run PM motor is realized through a combination of symmetrical components and d-q axes theory. The developed approach is valid for any m-phase AC motor-induction, synchronous reluctance, or synchronous PM.

Analysis of magnetization of magnet in the rotor of line start permanent magnet motor

Line start permanent magnet motor (LSPM) is an effective model of a high-efficiency motor at a constant velocity. Post-assembly magnetization is necessary to reduce manufacture costs. The purpose of this paper is to design the magnetizing fixture and analyze the magnetization characteristics. First, the magnetizing fixture reducing the eddy current is designed. Second, the magnetization of NdFeB magnetized by the designed fixture is analyzed. The time-stepping finite-element method combined with the Preisach model is used to analyze the magnetizing magnetic field intensity and to calculate the magnetization vector. With the magnetization vector, the surface flux density and back-electromagnetic force of the LSPM are calculated and compared with experiment results, which, in turn, agree well with the analysis results.

Performance of skewed single-phase line-start permanent magnet motors

In this paper, the authors investigate the modeling of single-phase line-start permanent magnet motors using finite-element (FE) analysis. It is shown that FE modeling is capable of giving very accurate predictions when compared with test results, for both skewed and unskewed motors. The skewed motor is also modeled using an analytical method. The accuracy of the FE method is contrasted with that obtained using the analytical method.

Line start permanent magnet motors with different materials

This paper describes the principle characteristics of two permanent magnet excited AC-motors with line start capability designed for the same minimum performance requirements within the same frame size. The basic design equations allow to explain the influences of the two different magnet materials. The building and testing of one of the motors verifies the model used for the design.