In recent years, medium-voltage variable-speed drives have become popular in the industry. However, in some applications, the use of long cables can lead to overvoltages at the motor terminals, affecting the motor lifespan. Under such conditions, the use of passive filters is recommended. However, the use of inductive capacitive (LC) filters results in resonances, leading to control stability issues. This issue can be mitigated by introducing a resonance damping strategy. In this work, four damping strategies are implemented and designed: Passive damping, capacitor current feedback, capacitor voltage feedback, and notch filter-based damping. The paper performs a comparative study on the current control phase margin, current and voltage harmonic spectra, and overall changes in the control structure. Then, the effect of the damping strategy on the VSD control is evaluated, creating guidelines to support the selection of the appropriate damping strategy. The results indicate that capacitor voltage feedback stands out, since this strategy presents an interesting dynamic behavior while allowing the elimination of the passive damping losses at a relatively low cost.

The growing demand for energy in remote and isolated regions, where access to the conventional electrical system is limited, has been driving the development of off-grid systems. A common type of off-grid power system employs photovoltaic systems associated with battery banks. However, these systems face challenges due to their remote location and their reliance on weather conditions for energy generation. Furthermore, it is crucial that these systems can communicate operational discrepancies, notify maintenance teams, and receive commands to activate energy-saving modes during adverse weather conditions. This work presents a simple and cost-effective approach to enhance the operation of an off-grid system, transforming it from a conventional system into an intelligent operation using the cloud-based platform known as ``thingable!''. The results highlight a cloud interface creation that enables the control of a pumping system. This interface is enabled by monitoring operational parameters, such as voltage, IGBTs temperature, and power delivered. To validate the proposed changes, a monitoring test was carried out using a controlled pump from 9:10 a.m. to 10:10 a.m., powered by an inverter connected to a 100 V DC bus. Additionally, a test was conducted to assess the pump behavior under a fixed duty cycle of 60\%.