Synchronous Reference Frame Grid Current Control for Single-Phase Photovoltaic Converters

This paper proposes a high performance control in a d-q reference frame for a single-phase grid connected converter. The proposed control allows to obtain easily an infinite control loop gain at fundamental frequency and a superior disturbance rejection: this assures only active current injection thus maximum conversion efficiency and decreases current distortion. The control has been implemented in a single-stage converter for single-phase PV systems. The converter is a standard full-bridge three-level voltage source inverter that delivers a sinusoidal current to the grid through an inductive filter and a line frequency isolation transformer. The transformer blocks out the DC components injected in the grid but the current feedback, closed around the output of the transformer, can lead to core saturation. To avoid saturation a compensation strategy has been developed relying on output current distortion in correspondence of voltage zero crossings. Simulation and experimental results confirm the effectiveness of the proposed control architecture and of the strategy adopted to avoid transformer core saturation.

[1]  S.M. Silva,et al.  Performance evaluation of PLL algorithms for single-phase grid-connected systems , 2004, Conference Record of the 2004 IEEE Industry Applications Conference, 2004. 39th IAS Annual Meeting..

[2]  N. Matsui,et al.  A control strategy of single-phase active filter using a novel d-q transformation , 2003, 38th IAS Annual Meeting on Conference Record of the Industry Applications Conference, 2003..

[3]  H. Stemmler,et al.  Stationary frame generalized integrators for current control of active power filters with zero steady state error for current harmonics of concern under unbalanced and distorted operation conditions , 2000, Conference Record of the 2000 IEEE Industry Applications Conference. Thirty-Fifth IAS Annual Meeting and World Conference on Industrial Applications of Electrical Energy (Cat. No.00CH37129).

[4]  S.M. Silva,et al.  Wide bandwidth single and three-phase PLL structures for grid-tied PV systems , 2000, Conference Record of the Twenty-Eighth IEEE Photovoltaic Specialists Conference - 2000 (Cat. No.00CH37036).

[5]  Donald Grahame Holmes,et al.  Stationary frame current regulation of PWM inverters with zero steady-state error , 2003 .

[6]  Frede Blaabjerg,et al.  Proportionalresonant controllers and filters for gridconnected voltagesource converters , 2006 .

[7]  Remus Teodorescu,et al.  Improved PLL structures for single-phase grid inverters , 2005 .

[8]  Liuchen Chang,et al.  A novel DSP-based current-controlled PWM strategy for single phase grid connected inverters , 2006, IEEE Transactions on Power Electronics.

[9]  M. Liserre,et al.  A new control structure for grid-connected LCL PV inverters with zero steady-state error and selective harmonic compensation , 2004, Nineteenth Annual IEEE Applied Power Electronics Conference and Exposition, 2004. APEC '04..

[10]  D.G. Infield,et al.  Power quality from multiple grid-connected single-phase inverters , 2004, IEEE Transactions on Power Delivery.

[11]  S.-K. Chung,et al.  Phase-locked loop for grid-connected three-phase power conversion systems , 2000 .

[12]  F. Blaabjerg,et al.  Control of single-stage single-phase PV inverter , 2006, 2005 European Conference on Power Electronics and Applications.

[13]  B. Saritha,et al.  Observer based current control of single-phase inverter in DQ rotating frame , 2006, 2006 International Conference on Power Electronic, Drives and Energy Systems.

[14]  Frede Blaabjerg,et al.  Proportional-resonant controllers and filters for grid-connected voltage-source converters , 2006 .

[15]  Donald Grahame Holmes,et al.  Stationary frame current regulation of PWM inverters with zero steady state error , 1999, 30th Annual IEEE Power Electronics Specialists Conference. Record. (Cat. No.99CH36321).