自动化专业英语课程第二版翻译

Closed-loop Control of DC Drivers

直流传动的闭环控制

A basic scheme of closed-loop speed control system employing

current

limit

control,

also

known

as

parallel

current

control,

is

shown

in

Fig.1-5b-1.

ω

m*sets

the

speed

reference.

A

signal

proportional

to

the

motor

speed

is

obtained

from

the

speed

is

obtained from the sped sensor.

应用限流控制，

也称为并联电流控制 的闭环速度控制系统的基本

示意图如图

1-5B-1

ω

m

*

为速度参考值。正比于电机速度

的信号可从速度传感器获得。

The

speed

sensor

output

is

filtered

to

remove

the

AC

ripple

and

compared with the speed reference. The speed error is processed

through a speed controller. The output of the speed controller Uc

adjusts the rectifier firing angle a to make the actual speed close to

the reference speed.

速度传感器的输出滤除交流波，

并与速度参考值比较，

速度误差

被速度控制器处理，速度控制器的输出

uc

调整整流器的触发角

α

，以使实际的速度接近 于参考速度。

The

speed

controller

is

usually

a

PI(proportional

and

integral

)

controller and serves three purpose- stabilizes the drive and adjusts

the

damping

ratio

at

the

desired

valued,

makes

the

steady-state

speed-error

close

to

zero

by

integral

action,

and

filters

out

noise

again due to the integral action.

速度控制器通常是

PI (

比例积分< /p>

)

控制器，

具有三种作用

——

稳

< br>定驱动，调整阻尼比到期望值；通过积分作用，使稳态速度误差

接近于零；还是由 于积分作用，可滤除噪音

The drive employs current limit control, the purpose of which is

to prevent the current from exceeding safe values. As long as Ia

where Ix is the maximum permissible value of Ia, the current control

loop does not affect the drive operation.

传动装置采用限流控制，

只要

IA

，其

Ix

是

IA

的最大允许值，电流控制回路并不影响驱动。

If

Ia

exceeds

Ix,

even

by

a

small

amount,

a

large

output

signal

is

produced by the threshold circuit, the current control overrides the

speed

control,

and

the

speed

error

is

corrected

essentially

at

a

constant current equal to the maximum permissible value.

如果

IA

超出

Ix

，

哪

0

怕一点点，

阈值电路也会产生一个大的输

出信号，

电流环代替速度环起主 要调节作用，

电枢电流等于电机

所允许的最大电流，并在此恒定 电流下对速度误差进行调整。

When

the

speed

reaches

close

to

the

desired

valued.

When

the

speed

reaches

close

to

the

desired

value,

Ia

falls

below

Ix,

the

current

control

goes

out

of

action

and

speed

control

takes

over.

Thus in this scheme, at any given time the operation of the drive is

mainly

controlled

either

by

the

speed

control

loop

or

the

current

control loop, and hence it is also called parallel current control.

当速度接近于期望值时，

IA

下降到

Ix

以下，

电流控制失效，速

度控制接替。因此，在此示意图中，在任意给定时间，传动装置

主要由速度控制回路或电流控制回路控制，

所以，

也叫并联电流

控制。

Another scheme of close-loop speed control is show in Fig.5B-2.

It employs an inner current

control loop within an outer

speed

loop.

The

out

of

the

speed

controller

e

is

applied

to

a

current

controller u adjusts the converter firing angle such that the actual

speed is brought to a value set by speed command

ω

m*.

闭环速度控制的另一种示意图如图

1-5B-2

所示。

在外环速度回

路中采用内环电流控制回路。 速度控制器的输出

ec

用于电流控

制 器，

为内环电流控制回路设置电流参考值

Ia*

。

电流控制器的

输出

uc

调整逆变器的触发角，以便使实际速度达到速度给定值

ω

m*

所设置的值。

Any positive speed error, caused by either an increase in the speed

command

or

an

increase

in

the

load

torque,

produce

a

higher

current reference I*.The motor accelerates due to an increase in Ia,

to

correct

the

speed

error

and

finally

settles

at

a

new

Ia*

which

makes

the

motor

torque

equal

to

the

load

torque

and

the

speed

error close to zero.

由速度给定或负载转矩的增加所引起的任何正的速度偏 差，

都会

产生更大的参考电流值

Ia*

。由于

Ia

增加，电机加速，以调整

速度误差，最终停留在新的

Ia*

值上 ，使电机转矩与负载转矩相

同，速度误差接近于零。

For any large positive speed error, the current limiter saturate and

the

current

reference

Ia*,is

limited

to

a

value

Iam*,and

the

drive

current not allowed to exceed the maximum permissible value. The

speed

error

is

corrected

at

the

maximum

permissible

armature

current until the speed error becomes small and the current limiter

comes out of saturation .Now the speed error is corrected with Ia

less than the permissible value.

对于任何大的正的速度误差，限流装置饱和，且电流参考值

Ia*

限制为

Iam*

， 传动装置的电流不允许超过最大允许值。在最大

允许电枢电流下纠正速度误差，