4/ 有二种类型的BLCD电机,一类是trapezoidal type, 另一类是sinusoidal type. sinusoidal type需要高分辨率的位置信息.(读后觉得有点想PMSM,即PMSM和BLCDM都是BLCD电机)
来自 BLDC Motor Model and Control.pdf
5/ PMSM与BLCDM差不多,看贴图右边BLCDM字样
来自 跑步機外轉式同步馬達控制器開發實務 Development of The Outer Rotor PMSM Controller for Treadmill
System
10/ The difference between PMSM and BLDC These are really the same thing. The term "brushless DC motor" is really a marketing term to encourage people to think of the motor with its associated drive as a drop-in replacement for a brush DC motor and its drive.
The early motors sold as brushless DC motors tended to be "trapezoidally wound" (i.e. to have trapezoidal back EMF profiles) so they could be reasonably commutated by simple switching techniques from the DC bus (usually called six-step commutation). These days, most of these motors are "sinusoidally wound" and optimally controlled with a more sophisticated sinusoidal commutation algorithm.
To further compound the confusion, some companies refer to trapezoidally wound motors as "brushless DC servos" and to sinusoidally wound motors as "brushless AC servos". I consider this a horrible distinction in terminology, because both motors require AC inputs to move in one direction; it's just that the shape of the optimal input is a little different.
摘自 http://www.control.com/thread/1026172925
14/ Permanent magnet motors: Are PMSMs the same as BLDCs?
There seems to be some confusion within the industry about the terms 損ermanent magnet synchronous motors?(PMSMs) and 揵rushless DC (BLDC) motors? I抳e talked with several different application engineers at different companies who抳e said that BLDCs and PMSMs are the same. But are they? It抯 true that they are both permanent magnet-based motors with the same basic structure, consisting of permanent magnets on the rotor and windings on the stator. The drive currents in the windings must be synchronized with rotor position feedback, which can come from sensors -- typically Hall effect -- on the rotor, or by evaluating the motor抯 back electromotive force (EMF). In general you抎 prefer to use a sensorless motor and save the additional part and cost.
One thing everyone agrees on is that the drive signals for the two motor types are different: A PMSM is driven sinusoidally, while a BLDC is driven trapezoidally making the PMSM much quieter, both electrically and mechanically. Plus, it has virtually no torque ripple.
So, while the basic architecture of the PMSM and BLDC motor is the same, their actual design at the detailed level is dictated by how they are driven. Here抯 how Dr. Aengus Murray of International Rectifier, explains the difference: 揂 PMSM is designed to have a sinusoidal back EMF, so the rotor is shaped to a sinusoidal flux profile. A BLDC motor needs to have trapezoidal back EMF, so the rotor needs to have a uniform flux profile.?
How does the different flux profile affect the physical motor design? 揂 BLDC needs to have a low winding inductance so it typically uses surface mounted rotor magnets. A motor with interior permanent magnet (IPM) rotor is not suitable for BLDC control because of the high inductance, but a PMSM controller can get 15% more torque from the IPM motor.?
Which raises the question, why doesn抰 everyone use PMSMs instead of BLDC motors? Because until recently programming the complex sinusoidal waveform control algorithms drove the development costs too high and required a more powerful (and more expensive) processor than what抯 needed for the relatively simple trapezoidal control of a BLDC motor. With the motor control development platforms recently introduced by companies such as IR, Microchip, Freescale, and STMicro, the algorithm development is already done for you, and you don抰 have to be a algorithm jock to use a higher-torque, low-noise, energy efficient PMSM.
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