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发表于 2016-3-23 23:27:09
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本帖最后由 mandylion2008 于 2016-3-24 10:47 编辑
好的,有空去看看,希望能取点经。
我估计用了库,要不就是开环拖动,没有见他们像我这样做一些堵转的测试。
今天看了一下开源的链接,有以下粗糙结论和摘录:
0. 确实没有使用ST的库,也没有什么高频注入法,就是强制拖动电机和负载超过一个最低允许的速度,在这个速度以上,基于EKF的估算器就可以正常工作了,于是切入闭环运行。
但是不用高频注入,是不可能在极低速下保持稳定的闭环运行的,这点应当是毫无疑义的。
不知道它能不能做到KV380的电机以轴上转速60RPM的稳定速度闭环?
如果有错,请大家指出。
1. <dt>motor_startup_current (index 3)</dt>
<dd>Motor start-up current in amps. This limits the current
setpoint until the motor reaches its minimum controllable RPM.
Higher values may speed up initial alignment, but may also result
in oscillation. Very high values may result in damage to the prop,
motor or ESC. A good starting point is normally 25% of the motor’s
rated maximum current.</dd>
2. <dt>motor_rpm_min (index 4)</dt>
<dd>Motor minimum controllable RPM. This is used to force the
motor to rotate before the state estimation filter has locked, and
also determines how long the motor_startup_current is used for.
The value depends on the motor’s Kv as well as the number of
poles; it should be low enough that the motor can lock onto the
rotation rate immediately, but high enough that the back EMF is
measurable.</dd>
3. <li>62.5 kHz PWM with space vector modulation and 10 bit per phase output resolution</li>
<li>31.25 kHz vector control with cascaded PID torque and speed controllers</li>
看了这个指标,我也准备玩一下STM32F301,计算速度快了,PWM也就可以更高些,更安静。
4. <p style="clear:both;padding-top:20px">
The S2740VC is a compact, high-performance ESC for motors up to
1000 W in UAV propulsion applications. Compared with conventional
ESCs, the S2740VC offers higher efficiency over most of the operating
range, better dynamic performance, significantly improved torque
control, lower acoustic noise, and lower vibration.
看来FOC还是有前途的!
5. EKF observer largely derived from:
Smidl, V. and Peroutka, Z. (2011)
"Reduced-Order Square-Root EKF for Sensorless Control of PMSM Drives"
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6119446
这个是摘要,确实好东西,为什么我们中国就没有这样的好论文,都是些国外论文的变异拼凑版?再不就是“随着电力电子技术的飞速发展。。。。。”之类的文章综述,当然这比高中老师发表的一些钻牛角尖的所谓论文强多了。
Performance of square-root extended Kalman filter (EKF) based on reduced order models for sensorless control of permanent magnet synchronous motor (PMSM) drives is studied. The reduced order model of PMSM has two-dimensional state vector comprising of: (i) electrical rotor speed, and (ii) electrical rotor position. These state quantities are estimated by the EKF without either speed or position sensor on the motor shaft. The reduction of the model order results in dramatic speed-up of calculation of the estimator which takes only a few tens of microseconds on a conventional fixed-point digital signal processor. Accuracy of the estimator is improved using square-root representation of the covariance matrix. Due to its low computational requirements, the proposed square-root EKF estimator is eligible for sophisticated diagnostics as well for sensorless control of PMSM drive in a wide range of industrial applications. Presented theoretical conclusions are verified by both simulations and experiments carried out on developed PMSM drive prototype of rated power of 10.7kW.
使用的这个估算器,果然是有了资料好办事,大学里的那些教授很多这样干的,IEEE好东西啊!
6. 因为这些单片机都具有FPU,所以在程序里都是浮点计算,对于连除法指令都没有的M0核来说,真的是想都不敢想的事。
7. 很疑惑,为什么这种开源的东西,如果效果真如YOUTUBE上展示的那么好的话,为什么国内还没有开始大规模山寨化呢?
成本太高?
效果一般?
8. 看到老外都在用STM32高端芯片做东西后,我认真的思考了一下,确实,有了好了芯片做起事来会顺手的多,以前一直以为STM32F301之类的很贵,要12块左右的样子,但听坛友们讲64K的才5,6块钱时,我心动了,用英飞凌的M0,有很 多好的想法不能实现,做起来真的很憋屈!他的ADC也证明了德国货也是人做的,不是神。真的要下决心突破STM32新建工程这关了,就凭STM32F301的性能和价格,绝对可以甩INFINEON 的XMC1400,XMC4108几条街了!
芯片一到,立马开始学习STM32F301的使用。希望得到大家的帮助,谢谢!
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