Abstract: The present invention provides a simplified method of controlling power among the various sources and loads in a power system. Power generating sources are each connected to a common DC bus through a converter. The converter selectively transfers energy to the DC bus at a maximum rate or at a reduced rate according to the level of the DC voltage present on the DC bus. At least one storage device is preferably connected to the common DC bus through a power regulator. The power regulator selectively transfers energy to or from the DC bus as a function of DC voltage level present on the DC bus. Further, an inverter may be provided to bidirectionally convert between the DC voltage and an AC voltage for connection to a customer load or the utility grid. Each power conversion device is independently controlled to provide a modular and simplified power control system.

Abstract: A power converter is configured to transfer energy from a photovoltaic (PV) array to a DC bus internal to the power converter. The power converter executes a modulation module to selectively connect one or more switching devices between the output of the PV array and the DC bus. The power converter is configured to operate in multiple operating modes. In one operating mode, the converter operates with a fixed modulation period and a variable on time, and in another operating mode, the converter operates with a variable modulation period and a fixed on time. The improved power converter provides highly efficient low power energy capture, improving power efficiency and enabling energy capture in low light conditions with reduced converter losses.

Abstract: An energy conversion system for use with an alternative energy source is disclosed. The alternative energy source can generate either an AC or a DC voltage. A first power converter is connected between the source and a DC bus, and a second power converter is connected between the DC bus and the grid or another load. The first power converter is configured to operate during periods of low energy generation. The energy captured will be stored in an electrical storage medium. When sufficient energy is stored, this energy is subsequently transferred to the grid or load via the second power converter. The second power converter is configured to operate intermittently during periods of low power generation, transferring energy from the DC bus when sufficient energy is stored and turning off when the stored energy drops to a point at which the second power converter can no longer be operated efficiently.

Abstract: A power converter configured to improve power capture in a wind turbine during low wind speed operation is disclosed. The power converter converts the power generated by the alternator of the wind turbine into a suitable AC current for delivery to a utility grid or to an electric load independent of the utility grid. The power converter is configured to operate in multiple operating modes, utilizing both synchronous and non-synchronous control methods, to extend the operating range of the power converter. During non-synchronous operation, the power converter utilizes a modulation routine that may either vary the dead-time compensation period during a constant modulation period or vary the modulation period with a constant on-time. A seamless transfer between non-synchronous and synchronous control methods with low total harmonic distortion (THD) improves the range of power generation for wind generators.

Abstract: Disclosed is method for enhancing electrolyte flowing mechanism within electrodes in flow battery cells by employing half-cell spacer screens that may be welded to at least one surface of each electrode sheet. Half-cell spacer screens may provide a constant gap thickness between electrode sheet and micro-porous separator membrane. Half-cell spacer screens may be made of a bromine inert thermoplastic such as polypropylene or polyethylene and may include at least one thin layer of strands. Additionally, the disclosed half-cell spacer screens may exhibit diamond pattern netting or any other suitable pattern. The inclusion of half-cell spacer screens may allow an improved distribution of electrolyte throughout the surface of electrode sheet, thereby improving performance flow batteries.

Abstract: An improved chemical composition and manufacturing process for a battery electrode are disclosed. This battery electrode may be later arranged in flowing electrolyte battery cells. Battery electrode material formulation may include a mixture of polypropylene, carbon black, graphite, bonding additives and other substances in different concentrations. The inclusion of graphite may reduce the amount of carbon black in the mixture, thereby reducing the swelling of the battery electrode in the presence of bromine. Moreover, material formulation may reduce warpage caused by the swelling of electrode material, and may additionally improve the performance and properties of flowing electrolyte batteries. An extrusion molding process may be employed in order to fabricate the disclosed battery electrode.

Abstract: Disclosed herein are formulation components for the manufacturing of a flow frame structure that can be integrated in flowing electrolyte batteries. These formulation components for manufacturing flow frames may include, but are not limited to, polypropylene, glass fiber, a coupling agent and an elastomer. A mixing and extrusion process may be employed to formulate the material and produce pre-formulated pellets for the manufacturing of flow frames. As flow frames may be integrated with electrodes (or membranes), the disclosed flow frame formulation may achieve a desired Melt Flow Index (MFI) range and may allow an improved bonding between electrodes (or membranes) and flow frame, therefore, simplifying manufacturing process and achieving higher performance and longer lifetime of flowing electrolyte batteries.

Abstract: The present disclosure details header flow divider designs and methods of electrolyte distribution. Internal header flow dividers may include multiple flow channels and may be built into flow frames. Flow channels within internal header flow dividers may divide evenly multiple times in order to form multiple flow channel paths and provide a uniform distribution of electrolytes throughout electrode sheets within electrochemical cells. Furthermore, uniform electrolyte distribution across electrode sheets may not only enhance battery performance, but also prevent zinc dendrites that may be formed in electrode sheets. The prevention of zinc dendrite growth in electrode sheets may increase operating lifetime of flow batteries. The disclosed internal header flow dividers may also be included within end caps of electrochemical cells.

Abstract: A power converter configured to improve power capture in a wind turbine during low wind speed operation is disclosed. The power converter converts the power generated by the alternator of the wind turbine into a suitable AC current for delivery to a utility grid or to an electric load independent of the utility grid. The power converter is configured to operate in multiple operating modes, utilizing both synchronous and non-synchronous control methods, to extend the operating range of the power converter. During non-synchronous operation, the power converter utilizes a modulation routine that may either vary the dead-time compensation period during a constant modulation period or vary the modulation period with a constant on-time. A seamless transfer between non-synchronous and synchronous control methods with low total harmonic distortion (THD) improves the range of power generation for wind generators.

Abstract: A method of starting a wind turbine generator of any type of polyphase AC machine, including, but not limited to, brushless DC or permanent magnet machines is disclosed. The machine starts from a dead stop or from low speed operation and is accelerated to the cut in speed for power production. The start-up is realized utilizing the common set of electrical conductors and the power converter also used for capturing the generated power. Under initial operation, the power converter executes a PWM modulation technique to drive the machine. Periodically, the PWM modulation is stopped to read the electrical position of the generator.

Abstract: A power converter is configured to transfer energy from a photovoltaic (PV) array to a DC bus internal to the power converter. The power converter executes a modulation module to selectively connect one or more switching devices between the output of the PV array and the DC bus. The power converter is configured to operate in multiple operating modes. In one operating mode, the converter operates with a fixed modulation period and a variable on time, and in another operating mode, the converter operates with a variable modulation period and a fixed on time. The improved power converter provides highly efficient low power energy capture, improving power efficiency and enabling energy capture in low light conditions with reduced converter losses.

Abstract: An energy conversion system for use with an alternative energy source is disclosed. The alternative energy source can generate either an AC or a DC voltage. A first power converter is connected between the source and a DC bus, and a second power converter is connected between the DC bus and the grid or another load. The first power converter is configured to operate during periods of low energy generation. The energy captured will be stored in an electrical storage medium. When sufficient energy is stored, this energy is subsequently transferred to the grid or load via the second power converter. The second power converter is configured to operate intermittently during periods of low power generation, transferring energy from the DC bus when sufficient energy is stored and turning off when the stored energy drops to a point at which the second power converter can no longer be operated efficiently.

Abstract: The present invention provides a simplified method of controlling power among the various sources and loads in a power system. Power generating sources are each connected to a common DC bus through a converter designed to optimize power flow to the DC bus. A DC storage device is connected to the common DC bus through a power regulator designed to maintain a constant voltage on the DC bus. Further, an inverter may be provided to convert the DC voltage to an AC voltage for a customer load or for connection to the utility grid. Each power conversion device is independently controlled to provide a modular and simplified power control system.