The closed-loop brain stimulation technique plays a key role in neural network information processing and therapies of neurological diseases. Transcranial ultrasound stimulation (TUS) is an established neuromodulation method for the neural oscillation in animals or human. All available TUS systems provide brain stimulation in an open-loop pattern. In this study, we developed a closed-loop transcranial ultrasound stimulation (CLTUS) system for real-time non-invasive neuromodulation in vivo. We used the CLTUS system to modulate the neural activities of the hippocampus of a wild-type mouse based on the phase of the theta rhythm recorded at the ultrasound-targeted location. In addition, we modulated the hippocampus of a temporal lobe epilepsy (TLE) mouse. The ultrasound stimulation increased the absolute power and reduced the relative power of the theta rhythm, which were independent of the specific phase of the theta rhythm. Compared with those of a sham stimulation, the latency of epileptic seizures was significantly increased, while the epileptic seizure duration was significantly decreased under the CLTUS. The above results indicate that the CLTUS can be used to not only modulate the neural oscillation through the theta-phase-specific manipulation of the hippocampus but also effectively inhibit the seizure of a TLE mouse in time. CLTUS has large application potentials for the understanding of the causal relationship of neural circuits as well as for timely, effective, and non-invasive therapies of neurological diseases such as epilepsy and Parkinson’s disease.

For the modular multilevel converter (MMC) based photovoltaic system, when the submodules (SMs) of MMC are connected to distributed photovoltaic (PV), power mismatches between legs and arms are the inherent problem. To eliminate the power mismatches, this article proposes a lightweight MMC-based grid-connected energy router (MGER) integrated PV and energy storage (ES). Large-scale PV and centralized ES are connected to horizontal three SMs through four-terminal dual-active-bridges (FDAB). The primary three full-bridges of which adopt synchronous switching to achieve mismatch power elimination between horizontal SMs, so legs power balance can be realized. In addition, the SMs three-phase symmetrical ripple-power can also cancel each other out under synchronous switching of primary FDAB, so as to achieve low capacitance and lightweight of MGER, and the MMC arms second-order circulating current can be also eliminated from root cause. In this article, the power mismatches analysis, MGER configuration, power mismatches elimination, control method, and lightweight implementation are discussed in detail. Finally, the correctness and effectiveness of the proposed scheme are verified by simulation and experiment.

This article proposes a common-mode voltage (CMV) suppression strategy for the cascaded H-bridge (CHB) based motor drive. CMV can be categorized into two components: the low-frequency component associated with the motor frequency, and the high-frequency component related to the switching frequency. Low-frequency CMV primarily originates from the voltage fluctuations of submodules (SMs), and a topology method of CHB cascading four-port dual-active bridges (CHB-FDAB) is proposed. The CHB-FDAB, in conjunction with synchronous modulation of FDAB three full-bridges cascading with three-phase SMs, can effectively mitigate SM voltage fluctuations and prevent the occurrence of low-frequency CMV, which can also create a reduction for cost and volume of system. High-frequency CMV is generated by the modulation of CHB-stage, and a novel carrier phase-shift pulse-optimization PWM (CPSPO-PWM) strategy is proposed. The CPSPO-PWM can ensure that the difference between the output voltage sums of the left and right arms of the all three-phase SMs is zero, effectively suppressing the generation of high-frequency CMV. Additionally, CPSPO-PWM exhibits minimal increases in current ripple, torque ripple, and system power loss. As a result, the complete suppression of CMV throughout the entire speed range of motor can be achieved. Finally, simulation and experimental results validate the effectiveness of the proposed strategy.