Zero-Voltage-Switching Sinusoidal Pulse Width Modulation Method for Three-phase Four-wire Inverter

ABSTRACT:  

A Zero-Voltage-Switching (ZVS) sinusoidal pulse width modulation (SPWM) method for three-phase four-wire inverter is proposed in order to achieve higher efficiency and power density. With the proposed modulation scheme, the ZVS operation of all switches including the main switches and the auxiliary switch can be realized. Besides, all seven switches operate at a fixed frequency. The ZVS SPWM scheme is introduced by considering the various combinations of the polarities in three-phase filter inductors currents and analysis of operating stages is presented. ZVS condition of the ZVS SPWM scheme is derived and discussions of ZVS condition for typical three-phase loads are also provided. In addition, the resonant parameters design and loss analysis are briefly investigated. Finally the proposed ZVS SPWM scheme is verified on a 10 kW inverter prototype with SiC MOSFET devices.

 KEYWORDS:

  1. Zero-Voltage-Switching (ZVS)
  2. Sinusoidal pulse width modulation (SPWM)
  3. Three-phase four-wire inverter

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig. 1. ZVS three-phase four-wire inverter.

 EXPECTED SIMULATION RESULTS:

         (a)                                        (b)

     (c)            (d)

Fig. 2. Three-phase load voltages and filter inductors currents of the ZVS inverter under balanced resistive load: (a) Three-phase load voltage, (b) load voltage and filter inductor current of phase A, (c) load voltage and filter inductor current of phase B, and (d) load voltage and filter inductor current of phase C.

(a)                    (b)

  •                                

(c)                                       (d)

Fig. 3. Three-phase load voltages and filter inductors currents of the ZVS inverter under unbalanced resistive load: (a) Three-phase load voltage, (b) load voltage and filter inductor current of phase A, (c) load voltage and filter inductor current of phase B, and (d) load voltage and filter inductor current of  phase C.

(a)                        (b)

 (c)                                     (d)

Fig. 4. Three-phase load voltages and filter inductors currents of the ZVS inverter under unbalanced inductive load: (a) Three-phase load voltage, (b)  load voltage and filter inductor current of phase A, (c) load voltage and filter inductor current of phase B, and (d) load voltage and filter inductor current of phase C.

 CONCLUSION:

 A ZVS SPWM method combining with aligned turn on gate signals and extra short circuit stage is proposed for three-phase four-wire inverter. The generalized ZVS condition of the ZVS SPWM scheme is derived and the discussions of ZVS condition for some typical three-phase loads are provided. For balanced resistive load, balanced inductive load and unbalanced resistive load, short circuit stage is required. The short circuit stage may not be needed during several intervals for some kinds of unbalanced inductive load. The estimated loss analysis show that significant efficiency advantages can be obtained by ZVS three-phase four-wire inverter at high switching frequency in comparison with the hard switching three-phase four-wire inverter.

The ZVS turn-on of all switches, including the main switches and auxiliary switch under both balanced and unbalanced resistive load are achieved in the complete fundamental period with experimental verification. Besides, the ZVS SPWM inverter shows significant efficiency advantage. The measured highest conversion efficiency of the ZVS SPWM inverter is 98.3 % and 1.7 % higher than that of the hard switching inverter. At full load, the ZVS SPWM inverter has 2.1 % higher efficiency than the hard switching inverter.

REFERENCES:

[1] M. E. Fraser, C. D. Manning and B. M. Wells, “Transformerless four-wire PWM rectifier and its application in AC-DC-AC converters, ” in IEE Proceedings – Electric Power Applications, vol. 142, no. 6, pp. 410-416, Nov 1995.

[2] M. Dai, M. N. Marwali, J. W. Jung and A. Keyhani, “A Three-Phase Four-Wire Inverter Control Technique for a Single Distributed Generation Unit in Island Mode,” in IEEE Transactions on Power Electronics, vol. 23, no. 1, pp. 322-331, Jan. 2008.

[3] E. L. L. Fabricio, S. C. S. Júnior, C. B. Jacobina and M. B. de Rossiter Corrêa, “Analysis of Main Topologies of Shunt Active Power Filters Applied to Four-Wire Systems,” in IEEE Transactions on Power Electronics, vol. 33, no. 3, pp. 2100-2112, March 2018.

[4] H. Zhang, C. da Sun, Z. x. Li, J. Liu, H. y. Cao and X. Zhang, “Voltage Vector Error Fault Diagnosis for Open-Circuit Faults of Three-Phase Four-Wire Active Power Filters,” in IEEE Transactions on Power Electronics, vol. 32, no. 3, pp. 2215-2226, March 2017.

[5] M. V. Manoj Kumar and M. K. Mishra, “Three-leg inverter-based distribution static compensator topology for compensating unbalanced and non-linear loads,” in IET Power Electronics, vol. 8, no. 11, pp. 2076-2084, 11 2015.

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