An Integrated 50 V Boost Controller With Digitally-Assisted MPPT for Submodule PV Applications

IEEE Open Journal of Power Electronics, vol. 4, pp. 221–236

Abstract

This work introduces an integrated maximum power point tracking boost controller for photovoltaic submodule applications. The IC offers a wide input voltage range from 7 V to 24 V, whereas the output voltage is actively limited to 50 V. The presented design utilizes discrete, low-ohmic MOSFETs for the output stage and thus supports input power levels up to 144 W. The converter operates with peak-current-mode control at 300 kHz switching frequency in continuous conduction mode. During light load operation, the control transitions to direct input voltage sensing pulse-frequency-modulation (PFM) with input and output voltage dependent peak inductor current. Moreover, the low-side resistive current sense is explained in detail together with an inductor current replication circuit for precise high-side turn-off. The maximum power point tracker (MPPT) is based on an adjustable resistive sense element and a delta modulator and achieves 99.9 % tracking efficiency, omitting any need for a high resolution analog-to-digital converter (ADC). In addition, the series connection of multiple DC/DC converters is examined. The peak system efficiency measures 98.4 %. The application-specific integrated circuit (ASIC) is manufactured in an 0.18$\mu$m HV-BCD process and occupies 6.25 mm2of silicon area.

Authors 7

1. Michael Hanhart Aachen Chair of Integrated Analog Circuits and RF Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Aachen, Germany

   Chair of Integrated Analog Circuits and RF Systems, RWTH Aachen University, Aachen, Germany

2. Léon Weihs Aachen Chair of Integrated Analog Circuits and RF Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Aachen, Germany

   Chair of Integrated Analog Circuits and RF Systems, RWTH Aachen University, Aachen, Germany

3. Leo Rolff Aachen Chair of Integrated Analog Circuits and RF Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Aachen, Germany

   Chair of Integrated Analog Circuits and RF Systems, RWTH Aachen University, Aachen, Germany

4. Jonas Zoche Aachen Chair of Integrated Analog Circuits and RF Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Aachen, Germany

   Chair of Integrated Analog Circuits and RF Systems, RWTH Aachen University, Aachen, Germany

5. Jan Grobe Aachen Chair of Integrated Analog Circuits and RF Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Aachen, Germany

   Chair of Integrated Analog Circuits and RF Systems, RWTH Aachen University, Aachen, Germany

6. Ralf Wunderlich Aachen Chair of Integrated Analog Circuits and RF Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Aachen, Germany

   Chair of Integrated Analog Circuits and RF Systems, RWTH Aachen University, Aachen, Germany

7. Stefan J. Heinen Aachen Chair of Integrated Analog Circuits and RF Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Aachen, Germany

   Chair of Integrated Analog Circuits and RF Systems, RWTH Aachen University, Aachen, Germany