Lab-Volt's 8010-A
System is a system that allows teaching of DC power electronics,
DC motor drives, single-phase, three-phase and thyristor power electronics,
as well as three-phase motor starters and motor drives. Let's take a look at the
equipment needed to teach this.
It uses a 48 volt lead acid battery pack
as well as our four-quadrant dynamometer/power supply;
in the power supply mode it supplies either up to + or - 150 volts
and can also be used as a current source. The IGBT chopper inverter can be
used
either with a single transistor, two transistors,
to create an H-bridge or to create a three-phase bridge.
There is also a dumping resistor to prevent over voltages on the DC bus.
There is protection against overheat,
overvoltage and overcurrent. All of the gates signals can be observed on an
oscilloscope or using our data acquisition system.
A variable resistive load allows seeing the influence of the load on the circuit,
and a variety of filtering inductors and capacitors allows switching frequency to
be varied from 400 Hertz
up to 20 Kilohertz. Data acquisition and control interface features four high-
voltage and high current inputs that are fully optically isolated,
as well as enough analog inputs to be able to
observe all of the gates and triggering signals. The control of the IGBT gate is
as simple as connecting the inputs of the gates to the output of the data
acquisition.
The system also allows you to take control of your transistors by
controlling things such as the duty cycle,
the switching frequency, acceleration and deceleration time,
as well as selecting the configuration from a multitude of different functions.
Once connected the data acquisition allows you to see all of the pertinent
signals on the oscilloscope.
Using the four-quadrant dynamometer to control the torque and to speed of
the DC permanent magnet motor,
the students will then create a buck chopper drive, a buck boost chopper drive,
and a four-quadrant chopper drive.
They will also do a DC motor control using speed and current feedback.
Using the rectifier and filtering capacitors along with transformers,
the students will then study power diode single-phase rectifiers,
single phase PWM inverters as well as
three-phase rectifiers, single-phase PWM inverters with dual polarity DC bus, and
three-phase PWM inverters.
The power thyristor module will be controlled with LV-DAC as well.
The individual SCRs can be linked together using two separate switches
and the firing control signals can be seen on the oscilloscope as well.
The students will though study the power thyristor,
single-phase AC power control as well as three-phase AC power control,
thyristor three-phase rectifier inverters,
and solid state relays. Using the three-phase squirrel cage motor
the students will then study direct online starters, soft starters,
and creative three-phase variable frequency induction motor drive,
and also a three-phase variable-frequency induction motor drive with constant
V/F ratio.
The power electronic system opens easily to high-frequency transformers,
home energy production, transmission lines, and so on.
The system features real power signals
while allowing full observation of all the relevant signals
and full control of this system power meters, making it
a powerful and flexible teaching system.