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 one embodiment is an improved variable speed engine/generator set with an integrated power conditioning system and control method including load shedding to generate high quality AC power with improved fuel efficiency and reduced emissions. The variable speed generator control scheme allows for load adaptive speed control of engine and generator field. The transformerless power inverter topology and control method provides the necessary output frequency, voltage and/or current waveform regulation, harmonic distortion rejection, and provides for single phase, or unbalanced loading.

Abstract: The invention in the simplest form is an improved variable speed engine/generator set with an integrated power conditioning system and control method, used to generate high quality AC power with optimum fuel efficiency and reduced emissions. The variable speed generator control scheme allows for load adaptive speed control of engine and generator field. The transformerless power inverter topology and control method provides the necessary output frequency, voltage and/or current waveform regulation, harmonic distortion rejection, and provides for single phase, or unbalanced loading.

Abstract: The invention in the simplest form is a power conditioning and inverting system for improved and efficient power generation. In particular, the present invention is a modulated dc link scheme that dramatically reduces the switching frequency ripple across the PWM output filter inductor and provides cost, size, and weight reductions, as well as efficiency enhancements. In a preferred embodiment of the present invention, the DC-DC converter control takes a feedback signal proportional to the inverter output voltage. This feedback is “summed” into the primary DC-DC volts command thereby causing the dc bus/link voltage to vary at a multiple of the output fundamental frequency causing the DC link to become a signal at a fundamental frequency voltage with a dc offset. The tooth modulator DC supply tracks the AC output voltage, reducing the difference between the applied DC volts and the AC output volts, thereby reducing inductor core losses.

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.