Abstract: An electronic equipment enclosure which regulates incoming outside air to within the operational limits of the electronic equipment within is described. The enclosure recirculates the wasted heat from the equipment to regulate both the temperature and humidity within the enclosure to acceptable levels without relying on any heating or air conditioning component. Thus, the enclosure assembly relies entirely on air flow for regulating the temperature inside the enclosure. Additionally, the recirculation feature of the enclosure allows the electronic equipment to operate at outside temperatures much lower than the stated operational range by modifying the temperature of the intake air of the equipment. A method of controlling the temperature inside an enclosure is also described.

Abstract: An electronic equipment enclosure which regulates incoming outside air to within the operational limits of the electronic equipment within is described. The enclosure recirculates the wasted heat from the equipment to regulate both the temperature and humidity within the enclosure to acceptable levels without relying on any heating or air conditioning component. Thus, the enclosure assembly relies entirely on air flow for regulating the temperature inside the enclosure. Additionally, the recirculation feature of the enclosure allows the electronic equipment to operate at outside temperatures much lower than the stated operational range by modifying the temperature of the intake air of the equipment. A method of controlling the temperature inside an enclosure is also described.

Abstract: A method for forecasting reduction in sunlight intensity due to cloud cover at a photovoltaic power plant is described. The method comprises determining characteristics of one or more clouds from sensors surrounding the photovoltaic power plant. The cloud characteristics are used to create a 3D map of the clouds. The 3D map in combination with information on the angle of the sun is used to create a 3D projection on the surface of the earth, resulting in a 2D surface irradiance map. The 2D surface irradiance map may be taken in successive projections or used in combination with wind speed data to forecast fluctuation in irradiance at the photovoltaic power plant. The forecasted reductions in power may be used to enact measures at the plant such as reducing the power output of inverters to prevent sudden fluctuations in the power output of the photovoltaic plant feeding the utility.

Abstract: A hybrid power converter system that comprises a first power bus connected to a DC power source, a second power bus connected to an AC load, and a third power bus connected to an energy storage device. One or more power converters are connected to the first power bus in parallel and are connected with the second and third power buses, each by a switch. The system includes a first switch for connecting or disconnecting a power converter to or from the second power bus and a second switch for connecting or disconnecting the power converter to or from the third power bus, to switch the source of power being provided to the AC load either from the DC power source or the energy storage device. With additional power converters connected into the system in a similar manner, several combinations of power supply are possible.

Abstract: Methods, systems, controller devices, and computer program products for reactive power control at a renewable energy site are provided. Embodiments address dynamic performance problems associated with control loop delay and the changing modes of operation for meeting utility voltage and reactive power constraints. Provided is a method for reactive power control involving: (a) determining a site-wide reactive power command comprised by a sum of a reactive power feedforward or compensation term and an integrator term; and (b) distributing the site-wide reactive power command among inverters.

Abstract: The present invention provides methods, systems, computer program products, and devices for renewable energy site power limit control that address conditions of plant saturation and loop delay. In an exemplary embodiment, power limit control of the present invention is broken into two levels of control: a site-wide real power limit control that produces a single site-wide command, SitePlimCom, for all inverters, and inverter-level power limit control that outputs a command, Inv[x].PlimCom[k], for individual inverters. In some embodiments, the invention has one or more of the following features: an integrator with nonlinear gains, limit based anti-windup, a power limit control term based on the sum of both integrator and feed-forward terms, and an inverter-level controller designed to meet slew rate and site power overshoot constraints.

Abstract: A hybrid power converter system that comprises a first power bus connected to a DC power source, a second power bus connected to an AC load, and a third power bus connected to an energy storage device. One or more power converters are connected to the first power bus in parallel and are connected with the second and third power buses, each by a switch. The system includes a first switch for connecting or disconnecting a power converter to or from the second power bus and a second switch for connecting or disconnecting the power converter to or from the third power bus, to switch the source of power being provided to the AC load either from the DC power source or the energy storage device. With additional power converters connected into the system in a similar manner, several combinations of power supply are possible.

Abstract: A method for forecasting reduction in sunlight intensity due to cloud cover at a photovoltaic power plant is described. The method comprises determining characteristics of one or more clouds from sensors surrounding the photovoltaic power plant. The cloud characteristics are used to create a 3D map of the clouds. The 3D map in combination with information on the angle of the sun is used to create a 3D projection on the surface of the earth, resulting in a 2D surface irradiance map. The 2D surface irradiance map may be taken in successive projections or used in combination with wind speed data to forecast fluctuation in irradiance at the photovoltaic power plant. The forecasted reductions in power may be used to enact measures at the plant such as reducing the power output of inverters to prevent sudden fluctuations in the power output of the photovoltaic plant feeding the utility.

Abstract: Methods, systems, controller devices, and computer program products for reactive power control at a renewable energy site are provided. Embodiments address dynamic performance problems associated with control loop delay and the changing modes of operation for meeting utility voltage and reactive power constraints. Provided is a method for reactive power control involving: (a) determining a site-wide reactive power command comprised by a sum of a reactive power feedforward or compensation term and an integrator term; and (b) distributing the site-wide reactive power command among inverters.

Abstract: The present invention provides methods, systems, computer program products, and devices for renewable energy site power limit control that address conditions of plant saturation and loop delay. In an exemplary embodiment, power limit control of the present invention is broken into two levels of control: a site-wide real power limit control that produces a single site-wide command, SitePlimCom, for all inverters, and inverter-level power limit control that outputs a command, Inv[x].PlimCom[k], for individual inverters. In some embodiments, the invention has one or more of the following features: an integrator with nonlinear gains, limit based anti-windup, a power limit control term based on the sum of both integrator and feed-forward terms, and an inverter-level controller designed to meet slew rate and site power overshoot constraints.

Abstract: A system and method for efficiently regulating the fuel consumption of a variable speed combustion engine used to control loads such as a hoist motor in a mobile gantry crane based on load motor speed commands issued by a crane operator. The system and method can rely on a programmable logic controller to issue engine fuel commands to regulate engine speed based on interpolations derived from data representing the relationship between load motor voltage and engine speed and data representing the relationship between engine speed and engine power capacity. The method may also be used in modified form by combustion engines which need digital fixed speed commands.

Abstract: A system and method for efficiently regulating the fuel consumption of a variable speed combustion engine used to control loads such as a hoist motor in a mobile gantry crane based on load motor speed commands issued by a crane operator. The system and method can rely on a programmable logic controller to issue engine fuel commands to regulate engine speed based on interpolations derived from data representing the relationship between load motor voltage and engine speed and data representing the relationship between engine speed and engine power capacity. The method may also be used in modified form by combustion engines which need digital fixed speed commands.

Abstract: A system and method for efficiently regulating the fuel consumption of a variable speed combustion engine used to control loads such as a hoist motor in a mobile gantry crane based on load motor speed commands issued by a crane operator. The system and method can rely on a programmable logic controller to issue engine fuel commands to regulate engine speed based on interpolations derived from data representing the relationship between load motor voltage and engine speed and data representing the relationship between engine speed and engine power capacity. The method may also be used in modified form by combustion engines which need digital fixed speed commands.

Abstract: A system and method for starting and regulating a wound rotor motor (120) including a phase-controlled SCR converter (150) and a drive circuit (130, 140) having a voltage source inverter (140) and a voltage source converter (130). The SCR converter (150) regulates power transmitted to the drive circuit from the rotor of the motor (120) so that the ratings of the drive circuit are not exceeded.

Abstract: A system and method for starting and regulating a wound rotor motor (320) including a phase-controlled SCR converter (350) and a drive circuit (330, 340) having a voltage source inverter (340) and a voltage source converter (330). The SCR converter (350) regulates power transmitted to the drive circuit from the rotor of the motor so that the ratings of the drive circuit are not exceeded. A shorting contactor (390) is employed in various embodiments to increase the efficiency of the circuit.

Abstract: A system and method for starting and regulating a wound rotor motor especially during the period between inactivity and a speed determined by the voltage ratings of the drive system. In a first embodiment, a starting resistor and a starting bypass contactor are connected between the rotor of the motor and a low voltage source inverter. In an alternative embodiment, the arrangement of the first embodiment is altered by connecting a shorting contactor on one side to the junction of the voltage source inverter, the starting resistor and the starting bypass contactor so as to be short circuited on the opposite side of the shorting contactor.

Abstract: A power conversion system for driving a load is provided. The power conversion system comprises a power transformer having at least one primary winding circuit and at least one secondary winding circuit, the primary winding circuit being electrically connectable to an AC power source. The system further comprises at least one power cell, each of the at least one power cell having a power cell input connected to a respective one of the at least one secondary winding circuit. Each power cell also has a single phase output connectable to the load. A power switching arrangement including at least one power switch is connected to the power cell input and a DC bus, and a switch controller is connected to the power switching arrangement and the power cell input. The power cell also has a PWM output stage having a plurality of PWM switches connected to the DC bus and the single phase output. A local modulation controller is connected to the PWM output stage.

Abstract: A power conversion system for driving a load is provided. The power conversion system comprises a power transformer having at least one primary winding circuit and at least one secondary winding circuit, the primary winding circuit being electrically connectable to an AC power source. The system further comprises at least one power cell, each of the at least one power cell having a power cell input connected to a respective one of the at least one secondary winding circuit. Each power cell also has a single phase output connectable to the load. A power switching arrangement including at least one power switch is connected to the power cell input and a DC bus, and a switch controller is connected to the power switching arrangement and the power cell input. The power cell also has a PWM output stage having a plurality of PWM switches connected to the DC bus and the single phase output. A local modulation controller is connected to the PWM output stage.

Abstract: A power conversion system for driving a load is provided. The power conversion system comprises a power transformer having at least one primary winding circuit and at least one secondary winding circuit, the primary winding circuit being electrically connectable to an AC power source. The system further comprises at least one power cell, each of the at least one power cell having a power cell input connected to a respective one of the at least one secondary winding circuit. Each power cell also has a single phase output connectable to the load. A power switching arrangement including at least one power switch is connected to the power cell input and a DC bus, and a switch controller is connected to the power switching arrangement and the power cell input. The power cell also has a PWM output stage having a plurality of PWM switches connected to the DC bus and the single phase output. A local modulation controller is connected to the PWM output stage.

Abstract: A power conversion system for driving a load is provided. The power conversion system comprises a power transformer having at least one primary winding circuit and at least one secondary winding circuit, the primary winding circuit being electrically connectable to an AC power source. The system further comprises at least one power cell, each of the at least one power cell having a power cell input connected to a respective one of the at least one secondary winding circuit. Each power cell also has a single phase output connectable to the load. An SCR arrangement including a gate drive and at least one SCR is connected to the power cell input and a DC bus. An SCR controller is connected to the SCR arrangement and the power cell input. The power cell also has a PWM output stage having a plurality of PWM switches connected to the DC bus and the single phase output. A local modulation controller is connected to the PWM output stage.