Common mode filter system and method for a solar power inverter

摘要

A photovoltaic system, method and apparatus are disclosed. In an exemplary embodiment, the system includes a photovoltaic array, a distribution system that distributes power within a premises of a demand-side energy consumer, an inverter coupled to the distribution system that is configured to convert DC power from the photovoltaic array to AC power and apply the AC power to the distribution system, a damping portion configured to damp high frequency voltages derived from the inverter, and trapping circuitry coupled to the damping portion that is configured to reduce a level of low frequency current traveling through the damping portion.

主权项

1. A photovoltaic system comprising:
a photovoltaic array; a distribution system, wherein the distribution system distributes power away from the photovoltaic array; N inverters coupled to the distribution system, each of the N inverters is configured to convert DC power from the photovoltaic array to AC power and apply the AC power to the distribution system; N attenuating components, each of the N attenuating components is coupled to a corresponding one of the N inverters, and each of the N attenuating components is disposed to attenuate common-mode high frequency voltages derived from each of a corresponding one of the N inverters, and each of the N attenuating components is disposed in series with a current loop to block common-mode currents in the current loop that includes a corresponding one of the N inverters, the photovoltaic array, ground, and the distribution system, thereby enabling each of the N inverters to be coupled to the distribution system without an isolation transformer, wherein a portion of the current loop between the photovoltaic array and ground is a capacitance of the photovoltaic array to ground, wherein the frequency of the high frequency voltages is a function of the switching of the N inverters; and N damping components disposed in parallel to the capacitance of the photovoltaic array to ground and sized to damp the common-mode currents which are potentially excited by the common-mode high frequency voltages derived from the N inverters and to prevent instability due to the attenuating components and the capacitance of the photovoltaic array to ground, each of the N damping components is coupled to a corresponding one of the N inverters, wherein N is greater than one.