Variable structure PWM controller for high efficient PV inverters

In general, the output voltage level of PV array varies widely at various irradiances and temperatures. The MPP (maximum power point) range of a medium- or high-power PV PCS is normally 450~830 Vdc or 300~600 Vdc. This means the PV PCS should operate in a wide range of modulation index. The PV PCS should satisfy the harmonic current requirement that TDD (total demand distortion) shall not exceed 5%. This paper proposes a new PWM control method for the medium- or high-power PV PCS which increases the efficiency of power conversion in all operation range with acceptable harmonic ripple currents. This paper compares and analyzes appropriate PWM schemes for the PV PCS in the view points of conversion efficiency and current harmonics.

[1]  Holmes,et al.  Pulse width modulation for power converters , 2003 .

[2]  Seung-Ki Sul,et al.  Minimum-loss strategy for three-phase PWM rectifier , 1999, IEEE Trans. Ind. Electron..

[3]  Tae-Jin Kim,et al.  A novel grid-connected PV PCS with new high efficiency converter , 2007, 2007 7th Internatonal Conference on Power Electronics.

[4]  Hyo-Sung Kim.  Filter Design for Utility Interactive Inverters using Single-phase Full-bridge Topology , 2007 .

[5]  J. Kolar,et al.  Influence of the modulation method on the conduction and switching losses of a PWM converter system , 1990, Conference Record of the 1990 IEEE Industry Applications Society Annual Meeting.