This chapter underscores the critical importance of addressing leakage current issues meticulously in the design of transformerless photovoltaic (PV) inverters. Such leakage has the potential to induce undesirable effects, including output current distortion and increased operational risks. Recognizing the traditional use of unipolar Sinusoidal Pulse Width Modulation (SPWM) in H-bridge inverters for its superior output performance, the chapter also acknowledges the drawback of a high-frequency common-mode voltage, leading to insignificant leakage current. To counteract these common-mode voltage fluctuations, the chapter delves into the application of neutral-point-clamped circuits, which effectively clamp the dc-link voltage, ensuring a constant common-mode voltage (CMV). Furthermore, the chapter studies existing 1-phase inverters that maintain a constant CMV and with several NPC-based clamping circuits principles namely as unidirectional and bidirectional variations are clearly investigated. Novel clamping circuits are introduced, which are a combination of both passive and active devices, namely novel neutral-point-clamped circuits (N-NPC). The chapter conducts a comparative analysis, assessing factors such as CMV, leakage current, number of switching count, and total harmonic distortion (%THD) to establish the superiority of the proposed topology over traditional neutral-point-clamped inverters. Validation of the theoretical framework is accomplished through simulation results, substantiating the practical applicability and effectiveness of the proposed design principles and topologies.