Optimal current waveforms for brushless permanent magnet motors

نویسندگان

  • Nicholas Moehle
  • Stephen P. Boyd
چکیده

In this paper we give energy-optimal excitation current waveforms for a permanent magnet synchronous motor that result in a desired average torque. Our formulation generalizes previous work by including a general back-EMF waveform, voltage and current limits, an arbitrary phase winding connection, a simple eddy current loss model, and a trade-off between power loss and torque ripple. Determining the optimal current waveforms requires solving a small convex optimization problem. We give a fast algorithm to find the optimal current waveforms in around 400μs; changes in required torque can be handled in around 200μs even on low-cost processors. We show that for an ideal motor with sinusoidal back-EMF, the optimal current waveforms increase efficiency by several percent in the constant power region. We also show that, for our model parameters, a sinusoidal back-EMF gives no performance benefit over a trapezoidal back-EMF, even in the constant power region, provided the optimal current waveforms are used. Another advantage of on-line optimization is the ability to adapt in real time to changes in the model or requirements, such as changes in resistance as winding temperature varies, or even gross changes like the failure of one winding. Mechanical Engineering Department, Stanford University. [email protected] Electrical Engineering Department, Stanford University. [email protected]

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Design and optimization of dc brushless permanent magnet motor

Electric motors that have found wide application in various sectors of industry Have unique features such as high reliability, high efficiency, quick acceleration and have small sizes. Brushless DC motors meet these requirements well. In this study, the design of a brushless DC motor speed limits for the particular application at 1800 rpm that can be equivalent to 140 watts output was provided....

متن کامل

Energy Saving in Evaporative Coolers using Permanent Magnet Brushless Motors

Due to low cost, evaporative coolers are used in most of the central regions and in the warm and dry climate of Iran and are considered as one of the major consumers of electrical power. Most evaporative coolers use single-phase induction motors by connecting directly to the power grid. But their eefficiency is very low, and their replacement with high efficiency electric motors is considered b...

متن کامل

A New Hybrid Brushless DC Motor/Generator without Permanent Magnet

The Brushless DC (BLDC) motor is a simple robust machine which has found application over a wide power and speed of ranges in different shapes and geometry. This paper briefly reviews the fundamentals behind the motor and also the different types of BLDC motors with different geometries and then presents a new configuration for BLDC motor/generator, which does not use a permanent magnet in the ...

متن کامل

Double Layer Magnet Design Technique for Cogging Torque Reduction of Dual Rotor Single Stator Axial Flux Brushless DC Motor

Cogging torque is the major limitation of axial flux permanent magnet motors. The reduction of cogging torque during the design process is highly desirable to enhance the overall performance of axial flux permanent magnet motors. This paper presents a double-layer magnet design technique for cogging torque reduction of axial flux permanent magnet motor. Initially, 250 W, 150 rpm axial flux brus...

متن کامل

A Novel Technique on the Analytical Calculation of Open-Circuit Flux Density Distribution in Brushless Permanent-Magnet Motor

Both the cogging and electromagnetic torques depends on the shape of the flux density distribution in the airgap region. A two-dimensional (2-D) analytical method for predicting the open- circuit airgap field distribution in brushless permanent magnet motors, considering the direction of magnetization, i.e., radial or parallel, and the effect of real shape of stator slot-openings is presented i...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Int. J. Control

دوره 88  شماره 

صفحات  -

تاریخ انتشار 2015