A Cell-Level Differential Power Processing IC for Concentrating-PV Systems With Bidirectional Hysteretic Current-Mode Control and Closed-Loop Frequency Regulation

Abstract

This paper describes an integrated power management IC with bi-directional current capability, aimed at compensating differences in output current between series-connected cells in Concentrating Photovoltaic (CPV) systems. The integrated 3.6 MHz power stage allows building a small-form-factor converter per cell. A Hysteretic Current-Mode Controller (HCMC) regulates the bi-directional converter's current to equalize neighbouring cell voltages. A Phase-Locked Loop (PLL) controls the inductor current ripple around the average value to stabilize the switching frequency. The use of Hysteretic Current-Mode Control with a novel bi-directional senseFET scheme provides inherent current protection and high reliability. The converter can operate from an input voltage as low as 1.8 V and with an inductor current up to ±1.5 A, while achieving a system efficiency above 90% for current mismatches between cells up to 60%. Measurement results show that the converter maximizes the output power of series-connected CPV cells with mismatched output currents. Index Termsdc-dc power conversion, photovoltaic power systems, integrated circuit design, analog integrated circuits, power converter, power electronics, current control, energy harvesting.

Review, Comparison, and Proposal for PWM Converters Integrating Differential Power Processing Converter for Small Exploration Rovers

“…DPP converters, which essentially are a bidirectional converter, transfer power between adjacent modules, as shown in Figure 3b, so that electrical characteristics of all modules are artificially unified even under partial shading conditions [3][4][5][6][7][8][9][10][11][12][13][14][15]. Since these DPP converters process only the power difference between adjacent modules, the power rating of the DPP converter can be rather smaller than that of micro-converters [3].…”

“…DPP converters for adjacent PV modules: (a) Bidirectional pulse width modulation (PWM) converter[3][4][5][6][7][8], (b) multistage chopper[9,10], (c) switched capacitor converter[11][12][13][14].…”

Virtual inertia provision through data centre and electric vehicle for ancillary services support in microgrid

“…Several studies have focused on the regulation of MG frequencies and have used alternate methodologies for frequency control [8]. Researchers address photovoltaic (PV)‐based MG's [9] and describe different topologies of PV inverters [10]. However, the authors have not used any ESS as a backup for the MG.…”

Family of transformerless pulse‐width modulation converters integrating voltage equalisers for PV panels and energy storage modules

“…To mitigate or even eliminate the mismatch issues of PV panels and series-connected energy storage devices, various kinds of voltage equalisers have been proposed for PV panels [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] and energy storage modules , respectively -they are usually called differential power processing converters for PV panels. In spite of the application difference, their basic operating principles and roles are identical; power redistribution from stronger substrings/devices to weaker ones via equalisers.…”

“…Since a variety of voltage equalisers have been proposed, proper equaliser topologies are selected depending on power redistribution strategies. Non‐isolated bidirectional converters such as pulse‐width modulation (PWM) converters [2–8, 22, 23] and switched capacitor converters [9–12, 24–28] are used for power transfer between neighbouring substrings/devices. To redistribute power/energy of the string to substrings/devices directly, single‐input–multi‐output converters such as multi‐winding flyback converter [13, 29, 30], multi‐stacked buck–boost converters [14, 15, 31], voltage multipliers [16, 17, 32–34] etc.…”