Abstract: In distributed green-energy architectures, where a customer location has energy storage as well as local generation, the present application provides techniques which advantageously prevent the battery from being charged from the grid. This is preferably implemented by using voltage-level signaling to limit power transfer from grid to battery, thereby 1) allowing transfer from PV to battery, and 2) preventing “round-trip” transfer of net energy from grid to battery to grid. This is particularly advantageous where net energy metering is allowed, or where any analogous form of preferential pricing is given to green energy (or to solar energy specifically).

Abstract: An active anti-islanding architecture where a power converter injects a current component at a harmonic of the fundamental power frequency is injected with a phase sequence opposite to that which normally be present with that harmonic. (For example, a 5th harmonic frequency can be used with a positive phase sequence, or a 7th harmonic frequency with a negative phase sequence.) The injected current component can have a thousandth or less of the power transferred by the converter, since the distinctive phase sequence of the injected signal facilitates recognition of a corresponding term in the observed voltage.

Abstract: Power converters, and microgrids driven by such a power converter, in which the converter is controlled by a proportional controller which operates directly on AC waveforms, preferably without conversion to a DC type signal; preferably with use of voltage compensation to remove inherent error of proportional controller; and preferably with use of individual phase RMS voltages in the voltage compensation, to allow for normal operation under any load condition. Undervoltage of one or two phases is automatically compensated by adjusting the voltage of all phases, to retain balance. Line-starting of a motor load is automatically detected, and frequency droop is driven, apart from the other control relations in the system, to complete the line-starting operation as quickly as possible.

Abstract: Methods and systems for bi-directional multi-port power conversion systems and applications are disclosed. In some sample embodiments, current-modulating power converters can be used to provide conversion between synchronous and asynchronous power. In some sample embodiments, current-modulating power converters can perform power conversion can be performed to and from three-phase AC with an active neutral line. In some sample embodiments, current-modulating power converters can convert between synchronous and asynchronous power and also support three-phase AC with active neutral.

Abstract: Methods and systems for bi-directional multi-port power conversion systems and applications are disclosed. In some sample embodiments, current-modulating power converters can be used to provide conversion between synchronous and asynchronous power. In some sample embodiments, current-modulating power converters can perform power conversion can be performed to and from three-phase AC with an active neutral line. In some sample embodiments, current-modulating power converters can convert between synchronous and asynchronous power and also support three-phase AC with active neutral.

Abstract: Methods and systems for managing link voltages in a power converter, where single phase, three phase or universal systems can be used. Common mode management refers to shifting of voltages in a particular direction to perform transition between input and output ports, in addition to maintaining soft switching property. Voltages in power converters can be freely increasing and decreasing, and thus damage to the circuit can be caused if these voltages change are not controlled.

Abstract: Methods and systems for islanding detection in power generators, particularly power converters. The present innovative methods can disconnect the power converter from the power distribution grid. Islanding detection can be performed by detecting the difference in resistive impedance between the islanded and un-islanded conditions, using an input-output power and input-output voltage correlation technique. The present methods can shut down the power converter instead of allowing it to continue running without connection to the grid, which will protect line-worker safety.

Abstract: Methods and systems for managing link voltages in a power converter, where single phase, three phase or universal systems can be used. Common mode management refers to shifting of voltages in a particular direction to perform transition between input and output ports, in addition to maintaining soft switching property. Voltages in power converters can be freely increasing and decreasing, and thus damage to the circuit can be caused if these voltages change are not controlled.

Abstract: A car charging station in which battery buffering includes at least approximately as much energy as is required to charge one car rapidly. This is particularly advantageous when a photovoltaic array is connected through a power converter to charge the battery, and also to provide a lower rate of charge directly to the vehicle charge connections. Advantageously, a mains power connection can also be made through yet another port of the same multiport power converter.

Abstract: Methods and systems for managing link voltages in a power converter, where single phase, three phase or universal systems can be used. Common mode management refers to shifting of voltages in a particular direction to perform transition between input and output ports, in addition to maintaining soft switching property. Voltages in power converters can be freely increasing and decreasing, and thus damage to the circuit can be caused if these voltages change are not controlled.