Pdus210 Operation - PiezoDrive PDUS210 Manual

PDUS210 Operation

Overview
The operating principle of the PDUS210 is summarized in Figure 4. The transducer is connected
on the right hand side to the output transformer. The transformer converts the internal +/-24V drive
voltage to the desired output voltage range, for example +/-200V. By default, the output
connection to the transducer is electrically isolated from ground but the negative output can also
be internally grounded using the jumper shown.
During operation, the voltage and current in the transducer is used to estimate the phase ��. The
measured phase is then used to control the frequency of the signal generator by comparing it to
the phase set point ��
settling time of the closed loop system. The feedback gain is normally determined experimentally
by slowly increasing the gain until the desired performance is reached or the response begins to
become unstable.
The signal generator has a variable amplitude and the frequency is normally controlled by the
phase control loop. It is connected to the power amplifier, which drives the output transformer and
transducer.
Phase
Frequency
Setpoint
Controller
Figure 4. Internal PDUS210 operation (in constant voltage, resonance tracking mode).
Resonance Tracking
The resonance tracking system of the PDUS210 is illustrated Figure 3. The phase detector (M)
measures the impedance phase angle between the primary voltage and current. The phase
controller �� (��) varies the drive frequency to maintain a constant phase set point ��
��
usually equal to zero.
To operate at a series resonance (impedance minima), the phase controller gain must be positive
to create a stable operating point.
To operate at a parallel resonance (impedance maxima), the phase controller gain must be
negative to create a stable operating point.
PDUS210 V4
. The frequency controller stabilizes the feedback loop and controls the
������
Signal
Generator
Phase Detector
Power
Amplifier
Transformer
Transformer
Transformer
10
Transducer
Ground
Connection
Transformer
, which is
������
Modified 6/02/2021