A 100kHz digitally controlled 10kW, 2-channel solar MPPT converter using 3-level topology with >75W/in3 power density and >98.5% peak efficiency

Not much literature is available on the design and implementation of a high power (>5kW) high density solar MPPT converter (either buck or boost) targeting the 200-850V range and with multi-level topology, to target ~850VDC. This paper illustrates a 10kW MPPT controller implemented with SiC 650V MOSFETs but in a three-level flying capacitor configuration and it targets an input voltage of 425-850V with an output of 400V nominal. There are two independent channels with active current sharing on the common output 400V DC bus for feeding the battery bank or an inverter. The peak power conversion efficiency of the system exceeds 98.5% and a standard Perturb and Observe algorithm is used for the MPPT function. One single 32-bit STM32G4 ARM MCU controls all the functions of MPPT, Buck conversion of two channels, flying capacitor balancing of two channels, output regulation and protection. It is targeted at renewables and energy storage applications.