Abstract: A system and method of measuring atmospheric parameters in an enclosed space using instrumented objects having measurement sensors. The instrumented objects travel through the space randomly or along defined flight paths. As the instrumented objects travel through the space, the measurement sensors measure atmospheric parameters and store the measurements to a memory. The devices periodically upload the measured atmospheric parameters to a controller circuit. By using self-propelled objects to carry measurement sensors, the system and method disclosed herein allow for periodically sampling atmospheric parameters in the interior of an enclosed space at a number of locations greater than the number of measurement devices employed. With data points taken from various locations within a volume of an enclosed space, the system and method can realize a more efficient utilization of energy by adjusting mechanical controls of an HVAC system or a ventilation system, for example.

Abstract: A protection circuit for an alternative energy source comprises a primary path including an isolation element, e.g., diode or transistor, to prevent current backflow into the alternative energy source from the power device. A low resistance bypass path around the isolation element is also provided. In a protection mode, the bypass path is opened so current must flow through the primary path. In a bypass mode, the bypass path is closed to provide a low resistance path for current to flow from the alternative energy source to the power device.

Abstract: A system and method of measuring atmospheric parameters in an enclosed space using instrumented objects having measurement sensors. The instrumented objects travel through the space randomly or along defined flight paths. As the instrumented objects travel through the space, the measurement sensors measure atmospheric parameters and store the measurements to a memory. The devices periodically upload the measured atmospheric parameters to a controller circuit. By using self-propelled objects to carry measurement sensors, the system and method disclosed herein allow for periodically sampling atmospheric parameters in the interior of an enclosed space at a number of locations greater than the number of measurement devices employed. With data points taken from various locations within a volume of an enclosed space, the system and method can realize a more efficient utilization of energy by adjusting mechanical controls of an HVAC system or a ventilation system, for example.

Abstract: An intelligent power management system that includes a circuit breaker containing a PLC module that spans open contacts of the circuit breaker to provide a communication path for PLC messages between communication paths on each of the line and load sides of the circuit when the contacts are open. The contacts are motorized to permit remote operation through PLC messaging. Coupled to the PLC module is a controller, which controls the opening and closing of the motorized contacts under user control or via an adaptive load management algorithm that reduces peak power consumption and adapts a set of loads to changed power supply conditions. The controller can also dynamically alter operational current and fault threshold levels on a real-time basis based upon circuit requirements or environmental conditions. The algorithm runs a state machine and also manages loads in a limited power source environment such as when loads are powered by a generator.

Abstract: A phase locked loop (PLL) circuit provides ac devices, such as power inverters and power measurement devices, with a reliable means for synchronizing to ac electrical systems. In an exemplary embodiment, the PLL circuit is configured for operation with single-phase electrical systems and offers substantial noise immunity by basing its locking operations on measured fundamental components, i.e., measured x-y phasors, of the electrical system voltage. Further, with its phasor-based locking operations and with its timer/counter-based operation, the PLL circuit can be implemented partly or wholly in digital processing logic.

Abstract: A control circuit synchronizes an ac power inverter to the mains voltage of an electrical grid by matching the fundamental phasor components of the inverter's output voltage to the fundamental phasor components of the mains voltage. Once such matching meets an acceptable voltage error threshold, the control circuit initiates contactor closure, verifies contactor closure, and then initiates a changeover from voltage-mode control used in synchronization operations to a current-mode control of the inverter's output. The control circuit provides corresponding disconnection control when disconnection from the grid is desired, wherein the regulated power of the inverter is ramped down in controlled fashion until it reaches a lower threshold whereupon contactor opening is initiated. Once contactor opening is verified, regulation control reverts to stand-alone voltage mode control or to shut down, as needed or desired.

Abstract: A power inverter comprises a push-pull inverter circuit that includes a transformer having a primary winding coupled to a DC bus and a secondary winding coupled to an AC bus, main power switches coupling each end of the primary winding to a DC return, and one or more supplemental power switches coupling at least one end of the primary winding to a snubber bus. The supplemental switch at a given end of the primary winding forms a buck-mode converter in combination with the primary winding and the associated free-wheeling diode at that end of the primary winding, and can be controlled by a switching controller to effect energy transfer between the snubber bus and DC bus. The switching controller can be configured to control power flow between the DC, AC, and snubber buses by controlling the common-mode and differential-mode voltages of the primary winding via main/supplemental power switch control.

Abstract: A multivariable control system provides regulation for a plurality of control variables of interest based on selecting a particular one of the variables for regulation relative to a corresponding setpoint, while continuing to monitor the other variables and switching regulation control over to another one of the variables as needed to maintain all of them within their allowed ranges. The system includes one or more PID regulators that tune themselves for the particular variables selected for regulation control. In an exemplary embodiment, the control system is configured for controlling an alternative energy system, wherein it includes one or more power flow devices that control power flow between electrical energy storage devices (EESDs) and a common dc bus and/or power flow between the dc bus and an external ac electrical system.

Abstract: A power inverter includes a regulator circuit that controls real and reactive power output by the inverter. The regulator measures real and reactive output power by calculating x-phasor components of the inverter's voltage and current output waveforms. Phasor calculation can be adapted for one or more pairs of single-phase voltages and currents. Determining the fundamental in-phase and quadrature components of output voltage and current reduces computational complexity by permitting the regulator to perform its power control processing largely in a dc signal domain, and enables separate real and reactive power control. The power inverter can include islanding detection logic, which exploits the ability to separately control reactive power. Exemplary islanding detection logic is based on determining whether changing the amount of reactive power output by the inverter induces an output frequency shift.