Nec Energy Solutions, Inc.

Nec Energy Solutons, Inc.

Gregory Tremelling

Yevgeny Maltsev

Oleg Kerbel

Ron Amit

Harold Weiss

In an embodiment, an energy storage system includes one or more storage cells, charge/discharge circuitry, and charger wakeup circuitry. After the storage cells become depleted below an energy level threshold, the charge/discharge circuitry disconnects the storage cells from a main circuit associated with the storage system. The charger wakeup circuitry allows a limited amount of current to bypass the charge/discharge circuitry in order to present a current-limited voltage from the storage cells at the terminals. The voltage presented at the terminals is pulsed on and off when an external device is connected across the terminals. The voltage presented to the terminals is detected by the external device. After detecting the voltage, the external device performs an operation in response to detecting the condition.

Energy storage system charger wake-up

Systems and methods of pre-charging battery cells that can reliably pre-charge battery cells included in a plurality of series-connected battery modules. The systems and methods can monitor a value of a pre-charge current provided to the plurality of series-connected battery modules, as well as monitor a voltage level of the battery cells within each battery module. The systems and methods can further switchingly interrupt the pre-charge current within each battery module once it has reached a predetermined threshold current value or the battery cells within the battery module have been charged to a UVP level, causing a flyback current to flow into the battery cells of each battery module that have not yet been charged to the UVP level. Once the battery cells within each battery module have been charged to the UVP level, the systems and methods can provide a full-charge current to the plurality of series-connected battery modules.

Buck pre-charger for series-connected battery modules

Systems and methods of detecting ground faults in energy storage and/or generation systems that can detect ground faults on the DC and/or AC side of an energy storage/generation system, and generate warning signals and/or shutdown at least part of the system upon detection of such ground faults. The systems and methods can monitor levels of DC voltages and amplitudes of AC voltages occurring on the positive and negative side of a DC bus with respect to ground on the DC side of the energy storage and/or generation system, and process the monitored DC voltage levels and AC voltage amplitudes to detect a ground fault. Having detected such a ground fault, the systems and methods can generate a warning signal and/or shutdown at least part of the system, for example, by disconnecting a DC energy system from the DC bus, and/or by disabling a DC-to-AC bidirectional inverter included in the system.

Systems and methods of detecting ground faults in energy storage and/or generation systems that employ DC/AC power conversion systems

According to example configurations herein, a clamp circuit includes: i) a power dissipation circuit disposed between a first node and a second node of the clamp circuit, and ii) a capacitive element disposed in a control path between the first node and a control input of the power dissipation circuit. During operation, when a voltage spike occurs at the first node, such as caused by opening of a respective switch, the capacitive element in the control path conveys a portion of energy from the first node to control activation of the power dissipation circuit. That is, during the voltage spike, based on conveyance of the energy over the control path, the power dissipation circuit turns ON to dissipate the transient voltage, protecting a main power switch.

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Berlin, MA, United States of America

Gregory Tremelling