Aerotech BAL LINEAR AMPLIFIER SERIES, Руководство пользователя

Страница: 11 / 56

BA Linear Series User’s Manual Introduction
Version 1.5
Aerotech, Inc.
1-3
1.3. BAL Drive Package
A block diagram of the BAL Series servo amplifier is shown in Figure 1-2. This is a
simplified diagram of the internal modules of the BAL Series amplifier. Contained in the
drive is a 115/230 VAC 50/60 Hz step down toroidal isolation transformer that rectifies
its output to produce a
±
40 VDC or a
±
80 VDC bus depending on the model.
These buses power three class AB power amplifiers, each containing their own control
power supply and isolated current command input connections. These power amplifiers
work independently of each other, each only receiving a signal current command from the
control section, refer to Figure 1-2. In other words, each power amplifier has a current
regulating circuit and voltage regulating circuit, along with an adjustable current limit
time-out circuit and a dynamic power limit circuit.
The dynamic power limit circuit monitors the instantaneous power across each output
power transistor and clamps the incoming current command signal to a level just below
the second breakdown specification of the output transistor.
The current limit time-out circuit monitors the phase current. It sends a signal to the
control section to shutdown the entire servo amplifier, if the current in a given phase
exceeds a certain level (programmable) after a given time period. This time period is a
variable and depends on the amount of current above the programmed current threshold
level.
The control section contains its own is5,
±
12 VDC control supply. Depending on
the operating mode, the control section is responsible for accepting incoming current or
velocity command signals and providing digital or analog commutation processing on
these signals. In addition, it generates an internal velocity feedback signal from the
encoder, if the velocity mode is specified. Independent of the mode specified, the control
section produces three current command signals that are fed through opto-isolation to
each of the three amplifiers.