Abstract: An alternator system includes an input shaft, a planetary gear assembly, a variable resistance generator, and a control unit. The alternator assembly is structured to produce an output current having a frequency. The planetary gear assembly disposed between, and operatively coupled to, the input shaft and the alternator assembly. The planetary gear assembly has a planet gear carrier body with an outer radial surface having teeth. The variable resistance generator has an external generator shaft with a generator gear. The generator gear is structured to engage the outer radial surface teeth. The control unit structured to detect the frequency of the alternator assembly output current and to alter the resistance of the generator. The control unit is structured to maintain the frequency of the alternator assembly output current within a selected range by increasing or decreasing the resistance of the generator.

Abstract: An alternator system includes an input shaft, a planetary gear assembly, a variable resistance generator, and a control unit. The alternator assembly is structured to produce an output current having a frequency. The planetary gear assembly disposed between, and operatively coupled to, the input shaft and the alternator assembly. The planetary gear assembly has a planet gear carrier body with an outer radial surface having teeth. The variable resistance generator has an external generator shaft with a generator gear. The generator gear is structured to engage the outer radial surface teeth. The control unit structured to detect the frequency of the alternator assembly output current and to alter the resistance of the generator. The control unit is structured to maintain the frequency of the alternator assembly output current within a selected range by increasing or decreasing the resistance of the generator.

Abstract: The maximum power point (MPP) of a photovoltaic array that can be coupled to power inverter is determined. A capacitor on a DC-bus side of the inverter is used as a load from which I-V characteristics of the photovoltaic array can be generated. The photovoltaic array is connected to the capacitor, which has been previously discharged by a bleed down resistor. Short circuit current, open circuit voltage, and values of current and voltage as the capacitor charges are determined and used to generate I-V characteristics of the photovoltaic array. From the I-V characteristics, the MPP can be calculated.

Abstract: A power converter system advantageously employs a modular, bi-directionally symmetrical power converter assembly in a readily customizable configuration to interconnect a direct current power source to a three-phase alternating power grid. Connections external to the power converter assembly are selected to optimize the power converter system for a specific application, such as interconnecting a photovoltaic array to the three-phase electrical power grid. The electrical interconnections of various elements including isolation transformers, voltage sensors, and control switches are optimized to improve efficiency and reliability.

Abstract: A power converter system advantageously employs a modular, bi-directionally symmetrical power converter assembly in a readily customizable configuration to interconnect a direct current power source to a three-phase alternating power grid. Connections external to the power converter assembly are selected to optimize the power converter system for a specific application, such as interconnecting a photovoltaic array to the three-phase electrical power grid. The electrical interconnections of various elements including isolation transformers, voltage sensors, and control switches are optimized to improve efficiency and reliability.

Abstract: The maximum power point (MPP) of a photovoltaic array that can be coupled to power inverter is determined. A capacitor on a DC-bus side of the inverter is used as a load from which I-V characteristics of the photovoltaic array can be generated. The photovoltaic array is connected to the capacitor, which has been previously discharged by a bleed down resistor. Short circuit current, open circuit voltage, and values of current and voltage as the capacitor charges are determined and used to generate I-V characteristics of the photovoltaic array. From the I-V characteristics, the MPP can be calculated.

Abstract: An inverter circuit (10) has a plurality of voltage source inverters (VSI) coupled in parallel. Each of the voltage source inverters are coupled to a load (14). A synch signal source (12) generates a square wave from a fundamental operating frequency. The square wave generated by the synch signal source (12) is coupled to each voltage source inverter (VSI). Each voltage source inverter VSI has a timer counter (22), a microprocessor (26), and an inverter (32). The timer counter (22) is preferably a triangle wave generator that corresponds to the time since a rising edge of a synch signal (18) The microprocessor (26) samples the cyclic output signal (24) and determines a phase angle for the voltage source inverter. The phase angle and the voltage magnitude are provided to the inverter (32). The inverter (32) provides an output signal to the load that has the same phase angle as the outputs of the other phase inverters.