Advanced PET Control for Voltage Sags Unbalanced Conditions Using Phase-Independent VSC-Rectification

ABSTRACT:

Voltage Sags The power electronic transformer (PET) is an emerging technology that is quickly becoming a key component of the next-to-come power distribution networks (PDNs), due to its versatility on energy management, as well as, the improvement on the quality of the energy. PDNs are characterized by their unbalanced conditions, causing that PETs driven by conventional dq0 controls introduce current distortions on the primary winding of the transformer.

DAB

Voltage Sags Such distortion is evidenced in the 2! oscillations of Vd and Vq acting as harmonic sources. In this sense, this paper proposes a novel control approach for PETs. The key idea behind of this proposal consists of operating each phase independently, which is achieved through the enclosed rectification and the mitigation of the 2! Oscillations in a Dual Active Bridge (DAB) topology. The attained advantages by this control scheme are: (a) balancing of the primary winding currents; (b) unitary power factor; (c) negligible harmonic distortion; and (d) 2! oscillation mitigation on the DC bus.

KEYWORDS:

  1. AC-DC-AC
  2. Power conversion
  3. Power electronic transformer
  4. Dual active bridge
  5. VSC
  6. Unbalanced control
  7.  Voltage sags
  8. Unbalanced input voltages.

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. Three-phase VSC rectifier with an unbalanced control

EXPECTED SIMULATION RESULTS:

Fig. 2. Simulation for an unbalanced voltage sag during V a g = 1\0_; V b g = 0:5\ 􀀀 120_; V c g = 0:5\120__

.

Fig. 3. Simulation for an unbalanced voltage sag during V a g = 1\0_; V b g = 1\ 􀀀 120_; V c g = 0:1\120__

.

Fig.4. Simulation for an unbalanced voltage sag during V a g = 0:8\0_; V b

g = 0:6\ 􀀀 133:9_; V c g = 0:6\133:9__

.

Fig. 5. Simulation for an unbalanced voltage sag with dq0 control during V a g = 1\0_; V b g = 1\ 􀀀 120_; V c g = 0:1\120__

.

CONCLUSION:

Voltage Sags The main contribution of this work consists in a new control structure, which employ a phasorial approach with a single PI control, for PETs working on distribution systems where the operation with unbalanced input voltages is frequently. The capacity of this control of independently generate the modulation variables mabc i with different magnitudes and angles, reach a better performance than other control structures; dq0 Voltage Sags The main contribution of this work consists in a new control structure, which employ a phasorial approach with a single PI control, for PETs working on distribution systems where the operation with unbalanced input voltages is frequently. The capacity of this control of independently generate the modulation variables mabc i with different magnitudes and angles, reach a better performance than other control structures; dq0

AC

Voltage Sags For example, to mitigate the problems caused by unbalanced input voltages conditions. Under these input conditions in a PET, the advantages achieve by the proposed control are: (i) balanced AC input currents, (ii) sinusoidal AC input current, and (iii) PF = 1. Furthermore, the control structure is an easy-to-implement and requires no additional components. Finally, in this work, all the advantages mentioned above were validated by using simulation and a lab prototype.

REFERENCES:

[1] H. Chen and D. Divan, “Soft-switching solid-state transformer (s4t),” IEEE Trans. Power Electr., vol. 33, no. 4, pp. 2933–2947, 2018.

[2] H. Chen, A. Prasai, and D. Divan, “Dyna-c: A minimal topology for bidirectional solid-state transformers,” IEEE Trans. Power Electr., vol. 32, no. 2, pp. 995–1005, 2017.

[3] G. Brando, A. Dannier, and A. Del Pizzo, “A simple predictive control technique of power electronic transformers with high dynamic features,” in 5th IET Intern. Conf. on Power Electr., Mach. and Drives, 2010, pp. 1–6.

[4] K. K. Mohapatra and N. Mohan, “Matrix converter fed open-ended power electronic transformer for power system application,” in IEEE PES GM – Conversion and Delivery of Electrical Energy in the 21st Century, 2008, pp. 1–6.

[5] D. Wang, C. Mao, J. Lu, S. Fan, and F. Peng, “Theory and application of distribution electronic power transformer,” Electric Power Syst. Research, vol. 77, no. 3, pp. 219–226, 2007.

Leave a Reply

Your email address will not be published.