Analysis and Design of a Novel Three-Level LLCC Inverter ...

u filter
i filter
33.0kHz
66.0kHz
99.0kHz
Ch3: input voltage of filter u filter (50V/div), Ch2: Input current of filter (i filter , 5A/div)
Fig. 9 Experimental waveforms of tangential mode
Mathe1: Fast Fourier Transform (FFT) of piezo element voltage u Cp
Fig. 12 Experimental load voltage harmonic spectrum
[V]
[A]
t [s]
u filter and i filter : voltage and current of inverter output
Fig. 10 Simulation waveforms of tangential mode
VI. CONCLUSION
The three-level PWM inverter is more complex, but yields
less THD, smaller and lighter filter components and larger
bandwidth compared with resonant inverter.
LLCC filter exhibits the robustness in respect to parameter
variations and reduces filter components and cable volume due
to local reactive power compensation.
An FPGA is employed as controller by reason of its
flexibility, fast and parallel calculation property.
The control scheme comprising a hysteresis current control
is analysed in detail. The operation of the power supply
system is verified by simulation and measurement, but the
physical performance is restricted by the delay of current
measurement.
Until now the current measurement and current error
calculation are implemented fully digital. For the next step, a
fast hybrid version is being developed by using of analog
current error comparison in order to improve the dynamic and
reduce THD.
u Cp
i filter
Ch1: voltage of piezo element u Cp (50V/div), Ch2: Input current of filter (i filter , 5A/div)
Fig. 11 Experimental waveforms of tangential mode
ACKNOWLEDGEMENT
Thanks belong to the Europe Community for funding the
PIBRAC project under AST4-CT-2005-516111 as well as our
project partners
REFERENCES
[1] Homepage of the project PIPRAC, www.pibrac.org
[2] P. Jänker, B. A. Grohmann, D. van den Bossche, ”Actuator Technology
– Driver of Aerospace Systems Innovation”, Actuator 2004, Bremen,
Germany, pp. 168-175.
[3] R. Li, N. Fröhleke, H. Wetzel, J. Böcker, S. Ouchouche, E. Agostini, J.-
T. Audren, “Power Supply and Control Scheme for an Airborne
Piezoelectric Brake Actuator”, Proc. of 10th International Conference on
New Actuators (ACTUATOR), Juni 2006, Bremen.
[4] T. Schulte, N. Fröhleke, “Development of power converter for high
power piezoelectric motors”, Aupec 2001.