m********r
发帖数: 334 | 1 我在重复别人的电机建模，模型大概是
U=Ri + (Fi'/i')di/dt + (Fi'/theta')dTheta/dt
其中dTheta/dt = w 角速度
现在求i，总是遇到积分器在time 0的值为无穷大，如果输入很小就没事。这种情况是
一定是奇异点的问题吗？ | g******u
发帖数: 3060 | 2 simulink has a limit symbol, so when you integrate at zero you can get
saturated result. | l***g
发帖数: 1035 | 3 it's not a simulink problem. it's an initial condition problem. set your
initial phi's d or q to non-zero.
【在 m********r 的大作中提到】
: 我在重复别人的电机建模，模型大概是
: U=Ri + (Fi'/i')di/dt + (Fi'/theta')dTheta/dt
: 其中dTheta/dt = w 角速度
: 现在求i，总是遇到积分器在time 0的值为无穷大，如果输入很小就没事。这种情况是
: 一定是奇异点的问题吗？
| p***e
发帖数: 472 | 4 right, not the dtheta/dt, must be the flux linkage.
【在 l***g 的大作中提到】
: it's not a simulink problem. it's an initial condition problem. set your
: initial phi's d or q to non-zero.
| m********r
发帖数: 334 | 5 d or q 是什么？ PID吗？
【在 l***g 的大作中提到】
: it's not a simulink problem. it's an initial condition problem. set your
: initial phi's d or q to non-zero.
| m********r
发帖数: 334 | 6 从flux求电流一般应该怎么求？如图
(U-R*I) --> 1/S-->Flux
________________
Flux -->| |--->i(t)
Theta -->| Current Calc |
i(t)-->|________________|--->inductance(t)
【在 p***e 的大作中提到】
: right, not the dtheta/dt, must be the flux linkage.
| p***e
发帖数: 472 | 7 a motor has the following equations:
Eq. 1: d[Flux]/dt = [V] - R[i] +/- w * [Flux]
Eq. 2: [Flux] = [wL] * [i]
Eq. 3: Torque = [Flux] * [i]
Eq. 4: dw/dt = Torque - Tload
Eqs. 1 & 2 apply to both stator and rotor, just change the voltage values
accordingly.
To model a motor:
1, calculate theta from the integration of w;
2, transform v, i from abc to dq
3, from v and i, calculate Flux for next step;
4, from Flux, calculate i for next step;
5, from Flux and i of next step, calculate torque for next step;
6, from torque of next step, calculate speed for next step;
7, repeat to 1...
【在 m********r 的大作中提到】
: 从flux求电流一般应该怎么求？如图
: (U-R*I) --> 1/S-->Flux
: ________________
: Flux -->| |--->i(t)
: Theta -->| Current Calc |
: i(t)-->|________________|--->inductance(t)
| m********r
发帖数: 334 | 8 多谢，其实我算的是SRM，rotor没有电压。我开始用的是Model 1，根据公式
U = R*i + d[Flux]/di * di/dt +d[Flux]/d(theta) * d(theta)/dt
= R*i + (L + i*dL/di)*di/dt + i*dL/d(theta)*d(theta)/dt
如图1，输入电流和角度，输出做代数运算后积分，每次积分器都很容易输出无穷大。
然后我改用model 2, Flux作为输入，Flux=L(theta,i)*i,电感用多项式近似后变成电
流的四元方程，怎么算电流？求多项式的根？
还有，Eq4是不是还少了w*F?
【在 p***e 的大作中提到】
: a motor has the following equations:
: Eq. 1: d[Flux]/dt = [V] - R[i] +/- w * [Flux]
: Eq. 2: [Flux] = [wL] * [i]
: Eq. 3: Torque = [Flux] * [i]
: Eq. 4: dw/dt = Torque - Tload
: Eqs. 1 & 2 apply to both stator and rotor, just change the voltage values
: accordingly.
: To model a motor:
: 1, calculate theta from the integration of w;
: 2, transform v, i from abc to dq
| p***e
发帖数: 472 | 9 http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4602459
【在 m********r 的大作中提到】
: 多谢，其实我算的是SRM，rotor没有电压。我开始用的是Model 1，根据公式
: U = R*i + d[Flux]/di * di/dt +d[Flux]/d(theta) * d(theta)/dt
: = R*i + (L + i*dL/di)*di/dt + i*dL/d(theta)*d(theta)/dt
: 如图1，输入电流和角度，输出做代数运算后积分，每次积分器都很容易输出无穷大。
: 然后我改用model 2, Flux作为输入，Flux=L(theta,i)*i,电感用多项式近似后变成电
: 流的四元方程，怎么算电流？求多项式的根？
: 还有，Eq4是不是还少了w*F?
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