Abstract: Techniques for detecting an island in a system including a node that is operatively coupled to a primary power source (e.g., grid) and one or more distributed power generation sources are disclosed. In one embodiment, a current pulse is included in the output of a distributed power source. The grid voltage is monitored at the node to determine if a pulse-related disturbance occurs. If the grid is present, no pulse-related disturbance will manifest. If grid is down, then a pulse-related disturbance will manifest. Detection of the pulse-related disturbance is used to signal island detection.

Abstract: The invention in the simplest form is an improved AC inductor circuit design that is ideal for single boost, or split phase dual boost topologies, and other poly-phase systems improving input power factor and total harmonic distortion. The implementation is efficient, reliable, and flexible, utilizing a wide range of input voltages and currents (including synthesized input voltage waveforms other than sinusoids), and variable frequency voltage sources such as flywheels or micro-turbines, switches, such as IGBT, MOSFET, in combination with AC inductors and typical high frequency rectifier diodes, high frequency rectifiers, or even some line frequency rectifier diodes. The present invention is applicable to power supplies, motor drives, power conditioners, power generation equipment, hybrid power conditioning and distribution equipment, appliances, and flywheels.

Abstract: The invention in the simplest form is an improved transformerless 3 phase power inverter topology and control method for power distribution systems. This 3 phase power inverter system provides the necessary output voltage and current waveform regulation, harmonic distortion rejection, very low output impedance, and ultra low DC offset of the output AC power, even when exposed to a high magnitude of the non-linear, single phase, or the unbalanced loading.