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This work proposes, analyzes, designs, and validates superior topologies of UHGH converters that are capable of supporting extremely large conversion ratios up to ∼2000× and output voltage up to ∼4-12 kV for future mobile soft robots from an input voltage as low as the range of a 1-cell battery pack. Thus, the converter makes soft robots standalone systems that can be untethered and mobile. The extremely large voltage gain is enabled by a unique hybrid combination of a high-gain switched magnetic element (HGSME) and a capacitor-based voltage multiplier rectifier (CVMR) that, together, achieve small overall size, efficient operation, and output voltage regulation and shaping with simple duty-cycle modulation. With superior performance, power density, and compact size, the UHGH converters prove to be a promising candidate for future untethered soft robots.

Soft robots have the potential to fundamentally change interactions between robots and the surrounding environment, and between robots and animals, and robots and humans in ways that today's hard robots are incapable of doing. However, to realize this potential, soft robot actuators require extremely high voltage supplies of more than 4 kV. The electronics that can satisfy this need currently are either too large and bulky or unable to achieve the high power efficiency required for mobile systems. To meet this challenge, this paper conceptualizes, analyzes, designs, and validates a hardware prototype of an ultra-high gain (UHG) converter that can support extremely large conversion ratios up to ∼1000× to provide up to 5 kV output voltage from an input voltage of ∼5-10 V. This converter is demonstrated to be able to drive HASEL (Hydraulically Amplified Self-Healing Electrostatic) actuators, a promising candidate to realize future soft mobile robotic fishes, from an input voltage range of a 1-cell battery pack. The circuit topology employs a unique hybrid combination of a high-gain switched magnetic element (HGSME) and a diode and capacitor-based voltage multiplier rectifier (DCVMR) to enable compact magnetic elements, efficient soft-charging in all flying capacitors, and adjustable output voltage capability with simple duty-cycle modulation. Achieving an efficiency of 78.2% at 15 W output power, while providing 3.85 kV output from 8.5 V input, the proposed UGH converter proves to be a promising candidate for future untethered soft robots.

This work proposes, analyzes, designs, and validates superior topologies of UHGH converters that are capable of supporting extremely large conversion ratios up to ∼2000× and output voltage up to ∼4–12 kV for future mobile soft robots from an input voltage as low as the range of a 1-cell battery pack. Thus, the converter makes soft robots standalone systems that can be untethered and mobile. The extremely large voltage gain is enabled by a unique hybrid combination of a high-gain switched magnetic element (HGSME) and a capacitor-based voltage multiplier rectifier (CVMR) that, together, achieve small overall size, efficient operation, and output voltage regulation and shaping with simple duty-cycle modulation. With superior performance, power density, and compact size, the UHGH converters prove to be a promising candidate for future untethered soft robots. [ABSTRACT FROM AUTHOR]

The paper proposes an optimal control strategy for the interleaved flyback based microinverter to improve its efficiency over the entire operating range. This control scheme is based on the choice of an appropriate operating mode [1-converter discontinuous conduction mode (DCM), 1-converter boundary conduction mode (BCM), 2-converter DCM, and 2-converter BCM] at various instantaneous power magnitudes. The proposed control method reduces the fixed losses associated with the gate driver and the transformer at the low power level. It also reduces the switching losses that may result due to the extremely high-frequency operation of the BCM at the low power level. Additionally, it also reduces the conduction losses through low current peak due to BCM and equal current sharing between the two converters at the high power level. Switching losses, due to the low-frequency operation of the BCM at a high power level, are also reduced. Operating mode selection of the interleaved inverter at a particular power level is based on the information of optimal efficiency. Detailed calculations of peak current references have been carried out for the various operating modes of the interleaved flyback based microinverter. Simulation and experimental results have validated that the proposed control method results in better efficiency compared with the conventional (DCM, hybrid DCM/BCM, hybrid 1-converter/2-converter) control methods with the output current total harmonic distortion remaining within the specified limits. [ABSTRACT FROM AUTHOR]