ABSTRACT
A
fast and robust fixed switching frequency peak current controller for dc-ac
converters is presented. The method is specifically elaborated for single-phase
grid-connected distributed generation (DG) applications. This method is called generalized
peak current control (GPCC) as it can mimic any known pulse width modulation
(PWM) strategy. It is shown that additional control objectives can be achieved
by adaptive bands of the GPCC, which are proposed to provide active damping for
inverters with LCL output filters. The proposed approach features all the
advantages of peak current controllers such as simplicity, fast transient, and
optimum dynamic response; with the superiority of fixed switching frequency and
harmonic free output. Feasibility and performance of the controller is shown by
simulations and experimental results.
KEYWORDS:
1. Current
Control
2. DC-AC
Converters
3. Generalized
Peak Current Control (GPCC)
4. Switching
Scheme
5. Single-Phase
Grid-Connected Inverter
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig.
1. Block diagram of the proposed controller along with the cost effective
active resonant damping technique.
EXPECTED SIMULATION RESULTS:
Fig.
2. (a) Grid current for the LCL filter case when the active damping
branch
is disabled, (b) Current of inverter and grid with the proposed active damping.
Fig.
3. Dynamic performance evaluation of proposed GPCC. Peak current
reference jumps from 1A to 3A at t
= 0:1s.
CONCLUSION
A
fixed switching frequency Generalized Peak Current Control (GPCC) method for
inverters is proposed . While controlling the peak value of the inverters’
current, the proposed approach can mimic any known PWM strategy. As a result,
the GPCC features all the advantages of peak current controllers, along with a
fixed switching frequency and the clean output harmonic spectrum inheriting
from the original PWM scheme. It is shown that the proposed technique is able
to obtain additional control objectives by its adaptive bands. As an example,
the GPCC is applied to a unipolar PWM scheme and the controller is elaborated
for both Land LCL-type output filters. Demonstrating the advantages of resulting
controller, a simple active damping strategy based on adaptive bands of the
controller is proposed. Simulations and experimental results are presented to
validate the method.
REFERENCES
[1] R.
Gupta, “Generalized frequency domain formulation of the switching frequency for
hysteresis current controlled vsi used for load compensation,” Power
Electronics, IEEE Transactions on, vol. 27, no. 5, pp. 2526–2535, May 2012.
[2] F.
Blaabjerg, R. Teodorescu, M. Liserre, and A. Timbus, “Overview of control and
grid synchronization for distributed power generation systems,” Industrial
Electronics, IEEE Transactions on, vol. 53, no. 5, pp. 1398–1409, Oct 2006.
[3] L.
Malesani and P. Tenti, “A novel hysteresis control method for currentcontrolled
voltage-source pwm inverters with constant modulation frequency,” Industry
Applications, IEEE Transactions on, vol. 26, no. 1, pp. 88–92, 1990.
[4] L.
Malesani, L. Rossetto, and A. Zuccato, “Digital adaptive hysteresis current
control with clocked commutations and wide operating range,” Industry
Applications, IEEE Transactions on, vol. 32, no. 2, pp. 316– 325, 1996.
[5] B.
Bose, “An adaptive hysteresis-band current control technique of a voltage-fed
pwm inverter for machine drive system,” Industrial Electronics, IEEE
Transactions on, vol. 37, no. 5, pp. 402–408, Oct 1990.
