On the Input Resistance of a Reconfigurable Switched Capacitor DC-DC Converter-Based Maximum Power Point Tracker of a Photovoltaic Source

• Published in: IEEE transactions on power electronics Vol. 27; no. 12; pp. 4880 - 4893
• Main Authors: Peter, Pradeep K., Agarwal, Vivek
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.2012; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Applied sciences; Arrays; Capacitors; Charge transfer; Circuit properties; Converters; DC-DC power converters; Direct energy conversion and energy accumulation; Electric currents; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electrical power engineering; Electronic circuits; Electronics; Energy; Exact sciences and technology; Frequency modulation; frequency modulation (FM); Mathematical models; Maximum power; Natural energy; Photoelectric conversion; photovoltaic (PV) systems; Photovoltaic cells; Photovoltaic conversion; Pulse duration modulation; Pulse width modulation; pulse-width modulation (PWM); Radiation; Resistance; Signal convertors; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; switched capacitor (SC) circuits; Switches; Switching, multiplexing, switched capacity circuits; Topology; Tracking; Frequency modulation; Circuit parameter; Conversion rate; frequency modulation (FM); Switched capacitor networks; Electric power; Optimal operation; Photovoltaic array; pulse-width modulation (PWM); Reconfigurable architectures; Solar radiation; DC―DC power converters; Dynamic response; Sensitivity analysis; Switched capacity; Control system; Direct current convertor; Photovoltaic system; Secondary cell; Topology; switched capacitor (SC) circuits; Tuning; Sensitivity; Pulse duration modulation; Shadowing; photovoltaic (PV) systems
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2012.2192452

The use of a switched capacitor (SC) dc-dc converter for tracking the maximum power point (MPP) of a photovoltaic (PV) array with the possibility of partial shading is described. The SC converter topology can be reconfigured to maximize conversion efficiency depending on the solar radiation and load. A new control scheme for MPP tracking based on tuning the input resistance (R _{\rm IN} ) of the SC converter MPP tracker with a battery tied load to match the output resistance of the array at MPP is proposed. R _{\rm IN} of the SC converter MPP tracker is studied extensively. The limits of R _{\rm IN} and its sensitivity to Pulse-width modulation (PWM), frequency modulation (FM), and circuit parameters of the SC converter are analyzed. Based on the sensitivity analysis, the proposed control scheme consists of an inner FM loop for fine control, an outer PWM loop for coarse control, and a provision to increase the dynamic range of R _{\rm IN} with adjustments of certain converter circuit parameters. A hardware prototype of a 10-W SC converter-based MPP tracker is built. Experimental measurements on the hardware model confirm the theoretical analysis. An algorithm to implement the MPP tracking control scheme is also tested.