Due to differences of solar irradiance, ambient temperatures, or inconsistent degradation of photovoltaic (PV) modules, the unbalanced output power between cascaded H-bridge (CHB) legs will lead to the unbalanced or even distorted grid currents between three phases. This article proposes a novel CHB-based PV grid-tied system integrating centralized energy storage (CHB-PV/ES), which can realize power balanced operation by utilizing the centralized energy storage (ES) interconnecting the CHB three-phase sub-modules (SMs) by isolated DC/DC converter. In addition, the centralized ES group can facilitate the regulation between grid-tied power references and PV power generation, such as stabilizing the power injected into the grid by smoothing the PV power, as well as responding to changes in grid-tied power references. The configuration and security domain of PV and centralized ES SMs are critical factors for CHB-PV/ES, which are thoroughly analyzed in this article to ensure safe system operation. The simulation and experimental results validate the effectiveness of the proposed CHB-PV/ES scheme.

Jumping with controllable elevation is significant for insect-scale robots to improve terrain adaptability and to escape from risks. However, jumping robots based on soft materials with low stiffness cannot transmit displacement precisely, exhibiting poor control of jumping. Here, we propose a modified two-bars catapult mechanism combined with an asynchronous sequential releasing strategy to realize elevation controllable jumping. In this work, an 80 mg prototype robot, 56 (long) × 29 mm (wide) × 3 mm (high) mm in size, is designed with the controllable elevation range from 63° to 112°. The soft robot is mainly composed of a shape memory alloy actuator and four electrostatic pads acting as the lock/release structures. Elevation control is realized by asynchronously releasing the electrostatic pads in a small time interval (about 10 ms). A maximum jump height of 62 mm and a maximum half-distance of 41 mm are also achieved.