Abstract: A multi-phase power generation system for renewable energy, in which reactive elements (i.e., capacitors and/or inductors) can be selectively switched in and out in order to meet a particular power factor requirement, is provided. Each phase of the multi-phase power system receives generated powers from a set of inverters, and each phase has a set of switch reactive elements for making power factor adjustments to the power generated by the set of inverters. The power outputs of the set of inverters belonging to a particular phase are combined into a one combined ac power output, and the power factor adjustment for that particular phase is performed on the combined power output by the set of the switch reactive elements of that particular phase. In some embodiments, at least some of the inverters are micro-inverters that convert DC power from one or two solar panels to AC power.

Abstract: A multi-phase power generation system for renewable energy, in which reactive elements (i.e., capacitors and/or inductors) can be selectively switched in and out in order to meet a particular power factor requirement, is provided. Each phase of the multi-phase power system receives generated powers from a set of inverters, and each phase has a set of switch reactive elements for making power factor adjustments to the power generated by the set of inverters. The power outputs of the set of inverters belonging to a particular phase are combined into a one combined ac power output, and the power factor adjustment for that particular phase is performed on the combined power output by the set of the switch reactive elements of that particular phase. In some embodiments, at least some of the inverters are micro-inverters that convert DC power from one or two solar panels to AC power.

Abstract: A multi-phase power generation system for renewable energy, in which reactive elements (i.e., capacitors and/or inductors) can be selectively switched in and out in order to meet a particular power factor requirement, is provided. Each phase of the multi-phase power system receives generated powers from a set of inverters, and each phase has a set of switch reactive elements for making power factor adjustments to the power generated by the set of inverters. The power outputs of the set of inverters belonging to a particular phase are combined into a one combined ac power output, and the power factor adjustment for that particular phase is performed on the combined power output by the set of the switch reactive elements of that particular phase. In some embodiments, at least some of the inverters are micro-inverters that convert DC power from one or two solar panels to AC power.

Abstract: The invention is directed to a method, system and device for converting direct current (DC) electrical voltage from a fuel cell to an alternating current (AC) voltage. The inventive method regulates power drawn from the fuel cell and from a battery to maintain a substantially constant DC voltage across a DC bus, and inverts the DC voltage from the DC bus to the AC voltage. The method may further electrically isolate the fuel cell from the load. Also, the inventive method may prevent current from flowing to the fuel cell. The inventive method may also provide a charging current to the battery.

Abstract: A fuel cell is placed in parallel with a battery via a mechanical switch. The voltage is held nearly constant by the battery and the power flow is controlled by adjusting the fuel cell operating parameters (such as temperature or air flow) and by opening and closing the mechanical switch. The result is a system that operates at nearly constant voltage without the need for an expensive power conditioning system. The output of the system can then be processed via a traditional power conditioning system such as an inverter or dc-to-dc converter without the need for a wide range of input operating voltages. This reduces the cost and size of the fuel cell power conditioning system.

Abstract: The invention is directed to a method, system and device for converting direct current (DC) electrical voltage from a fuel cell to an alternating current (AC) voltage. The inventive method regulates power drawn from the fuel cell and from a battery to maintain a substantially constant DC voltage across a DC bus, and inverts the DC voltage from the DC bus to the AC voltage. The method may further electrically isolate the fuel cell from the load. Also, the inventive method may prevent current from flowing to the fuel cell. The inventive method may also provide a charging current to the battery.

Abstract: A system used to protect the occupants of a stationary motor vehicle, particularly unattended children and pets, from dangerous conditions occurring within the vehicle. The system comprises a sensor which senses dangerous environmental conditions such as high temperatures within the vehicle. In the preferred embodiment, the sensor is used with a transmitter to continuously transmit sound detected within the vehicle passenger compartment as well as transmitting information about any dangerous conditions which occur to a remotely located person. In a second embodiment, dangerous conditions trigger an alarm attached to the vehicle. The alarm amplifies the sound detected within the vehicle, such as a crying child, or a barking dog, and also produces a standard alarm sound alternated with an amplified voice declaring the dangerous condition.

Abstract: A fuel cell is placed in parallel with a battery via a mechanical switch. The voltage is held nearly constant by the battery and the power flow is controlled by adjusting the fuel cell operating parameters (such as temperature or air flow) and by opening and closing the mechanical switch. The result is a system that operates at nearly constant voltage without the need for an expensive power conditioning system. The output of the system can then be processed via a traditional power conditioning system such as an inverter or dc-to-dc converter without the need for a wide range of input operating voltages. This reduces the cost and size of the fuel cell power conditioning system.

Abstract: Differential measurement of a transformer magnetizing current and a delta-modulation technique is used to provide compensation for dc saturation of the transformer core, with faster response times, low losses, and with immunity to dc drift in the measuring electronics. During the half-cycle in which the output voltage transitions from its positive maximum to its negative maximum, the positive peak value of the magnetizing current is determined, and during the half-cycle in which the output voltage transitions from its negative maximum to its positive maximum, the negative peak value of the magnetizing current is determined. The positive peak magnetizing current value is compared to the similar value from the previous cycle, and the onset of core saturation in the positive direction is then determined. The negative peak magnetizing current value is compared to the similar value from the previous cycle, and the onset of core saturation in the negative direction is then determined.

Abstract: Batteries are often used for load-following, particularly in combination with generation sources that cannot respond to fast load changes. Batteries that display “memory” (i.e., their ability to operate correctly over their entire depth of discharge depends on their previous level of charge or discharge) cannot adequately follow loads. This invention allows the use of batteries that display “memory” in load-following applications.

Abstract: Notching in a switch-mode converter is compensated for to restore a sinusoidal output voltage waveform to the output of the converter, regardless of the load current level, power level, or power factor (both distortion and displacement power factor). Waveform smoothing for a waveform in a switch-mode converter having a DC bus voltage and an output filter inductance comprises determining a ripple current in the converter; determining a time-to-zero; determining a turn-on time; determining the lesser of the time-to-zero and the turn-on time; determining a duty cycle modification based on the lesser of the time-to-zero and the turn-on time; and applying the duty cycle modification to the waveform.

Abstract: A power conditioner interfaces a load to a fuel cell 10 that produces a low voltage that varies with the load. A dc-to-ac inverter 16 operates with a low voltage input provided by a dc bus 14. When a positive step load change occurs, a low voltage battery 22 provides power equal to the step change until the fuel cell 10 is able to provide enough power to support the entire load. The power from the battery 22 is supplied to the varying dc bus 14 through a boost converter 12. When very large positive load step changes occur, the battery can feed power to the dc bus through diode D1, rather than through the boost converter. Diode D1 does not need to be used, but its use allows the boost converter to be sized for common load changes rather than for the maximum possible load change (such as might be seen during a faulted output). A buck converter converts the variable voltage on the dc bus 14 to the appropriate float charging voltage of the battery.

Abstract: A power system is provided in which a grid supplies electrical power to a load and in which backup power is provided from one of a generator and a dc storage device. The power system includes a standalone inverter having an input and an output. The output of the standalone inverter is connected to the load. The power system includes a grid parallel inverter having an input and an output. The output of the grid parallel inverter is connected to the grid. A dc bus is electrically connected to the input of the standalone inverter and to the input of the grid parallel inverter.

Abstract: An electronic circuit, such as a UPS, interfaces a main ac power source and at least one secondary power source to a load. The secondary power source(s) may include one or more auxiliary generators, a flywheel motor generator or microturbine with high speed motor generator, and/or any of a variety of dc storage devices. The electronic circuit includes a dc bus, a first uncontrolled rectifier in combination with a first filter for coupling the main ac power supply to the dc bus, one or more additional uncontrolled rectifier(s) and filter(s) for coupling the auxiliary generator(s) to the dc bus, and a dc-to-ac inverter (between the dc bus and the load) for providing ac output power to the load. The advantages of reduced parts count, increased compatibility between the generator(s) and the electronic circuit, and a simpler method for paralleling many storage and generation devices with a very high power factor to the sources, regardless of the load power factor, are provided.

Abstract: A power supply system for providing long and short term backup power to a load comprises a microturbine system, a flywheel system, and a power electronics module. The microturbine system includes a microturbine attached to a first, high speed motor-generator that includes a first stator, and the flywheel system includes a flywheel attached to a second motor-generator. The microturbine system is started by a direct connection of a high frequency AC voltage output of the flywheel system (in the range of from about 500 Hz to about 2 kHz) to the stator of the first motor-generator. The direct connection of the high frequency AC voltage to the stator involves no intervening electronics.

Abstract: An electronic interface couples a combination of generation and storage devices with a power grid and/or a load. The interface comprises a DC bus; a DC storage device coupled to the DC bus; a first DC-to-AC inverter (N1) having a DC port operatively coupled to the DC bus, and an AC port; a second DC-to-AC inverter (N2) having a DC port operatively coupled to the DC bus, and an AC port; a switch (S4) for electrically coupling the AC port of the second DC-to-AC inverter to a first generator or an AC storage device; a first rectifier (D1) for coupling an AC output of the first generator to the DC bus; and a second rectifier (D2) for coupling an AC output of the AC storage device to the DC bus.

Abstract: The present invention relates to a method and apparatus for controlling the speed of an electronically commutated motor. Such motors typically include a rotor, a stator coil, and an electronic commutator for controlling electrical power flow from an electrical power source of predetermined frequency to the stator coil.