초록 ▼

One system of the present application includes an electric power generation device structured to provide an AC electric power output at a target frequency. This device includes: an electric power generator; a sensing arrangement structured to provide samples corresponding to magnitude of the AC elec

One system of the present application includes an electric power generation device structured to provide an AC electric power output at a target frequency. This device includes: an electric power generator; a sensing arrangement structured to provide samples corresponding to magnitude of the AC electric power output; and a controller including operational logic responsive to the sensing arrangement to calculate a peak amplitude as a function of a waveform period corresponding to the target frequency and two of the samples separated in time by a target duration of 20 to 30 percent of the waveform period and determine a zero crossing of the output from the peak amplitude and the target frequency. The operating logic is further structured to control operation of the device in accordance with the zero crossing.

대표청구항 ▼

What is claimed is: 1. A method, comprising: operating an electric power generating device to provide an AC electricity output to a load at a target frequency, the device including an electric power generator; sampling the AC electricity output at a first time to determine a first output magnitude

What is claimed is: 1. A method, comprising: operating an electric power generating device to provide an AC electricity output to a load at a target frequency, the device including an electric power generator; sampling the AC electricity output at a first time to determine a first output magnitude and at a second time to determine a second output magnitude, the second time being a target duration later than the first time, and the target duration being less than a one half a waveform period for the target frequency; determining a zero crossing of the AC electricity output after the first time from the first magnitude, the second magnitude, and the target frequency; and regulating the electric power generating device in accordance with the zero crossing of the AC electricity output. 2. The method of claim 1, wherein the target duration is approximately one quarter of the waveform period and the determining of the zero crossing includes: calculating a peak amplitude from the first magnitude and the second magnitude; and predicting the zero crossing based on the peak amplitude and the target frequency. 3. The method of claim 1, wherein the electric power generating device includes a controller and an inverter, the determining of the zero crossing includes calculating the zero crossing with the controller, and the regulating of the electric power generating device includes controlling the inverter with the controller. 4. The method of claim 3, wherein the controlling of the inverter targets a sinusoidal waveform for the AC electricity output. 5. The method of claim 3, wherein the generator is of a variable speed type, the device includes a rectifier coupled to the generator and the rectifier is coupled to the inverter by a direct current bus; and further comprising providing rotational mechanical power to the generator with an internal combustion engine. 6. The method of claim 1, wherein the AC electricity output is at least approximately sinusoidal and the target duration is between 20% and 30% of the waveform period. 7. A method, comprising: operating an electric power generating device to provide an AC electric power output to a load at a target frequency, the device including an electric power generator; sensing a first magnitude representative of the AC electric power output at a first time and a second magnitude representative of the AC electric power output at a second time, the second time being a target duration later than the first time, and the target duration being less than a waveform period for the target frequency; determining the peak amplitude of the AC electric power output from the first magnitude, the second magnitude, and the target duration; predicting a waveform characteristic as a function of the peak amplitude and the target frequency; and controlling the electric power generating device in accordance with a control signal corresponding to the waveform characteristic. 8. The method of claim 7, which includes: operating the electric power generator at different frequencies; providing the AC electric power output with an inverter included in the device; and adjusting operation of the inverter in accordance with the control signal. 9. The method of claim 7, wherein the waveform characteristic is representative of a zero crossing of the AC electric power output in a sinusoidal form and the target duration is between 20% and 30% of the waveform period. 10. The method of claim 7, wherein target duration is approximately 25% of the waveform period, and the sensing of the first magnitude and the second magnitude includes sampling voltage corresponding to the AC electric power output. 11. The method of claim 7, which includes: providing mechanical power to the generator with an internal combustion engine; providing DC electricity to a DC bus by rectifying electricity output by the generator; providing the DC electricity to an inverter; and providing the AC electric power output from the inverter. 12. The method of claim 7, which includes: repeating the sensing, the determining, and the predicting on a periodic basis; and updating the control signal on in accordance with the repeating. 13. The method of claim 7, wherein the AC electric power output is sinusoidal, the waveform characteristic changes in response to a change in the load, and the controlling of the device includes adjusting the control signal in accordance with the change in load to regulate the AC electric power output to a target frequency and power factor. 14. The method of claim 7, wherein the function to calculate the peak amplitude corresponds to a square root of the sum of: the first magnitude squared and the second magnitude squared. 15. A system, comprising: an electric power generation device structured to provide an AC electric power output at a target frequency, the device including: an electric power generator; a sensing arrangement structured to provide samples corresponding to magnitude of the AC electric power output; a controller including operational logic responsive to the sensing arrangement to calculate a peak amplitude as a function of a waveform period corresponding to the target frequency and two of the samples separated in time by a target duration of 20 to 30 percent of the waveform period and determine a zero crossing of the output from the peak amplitude and the target frequency, the operating logic being structured to control operation of the device in accordance with the zero crossing. 16. The system of claim 15, wherein the device includes: means for converting variable frequency electricity output by the generator to DC electricity; and means for inverting the DC electricity to provide the AC electric power at the target frequency. 17. The system of claim 15, wherein the device includes: a rectifier coupled to the generator to convert variable frequency electricity from the generator to DC electricity; a DC bus coupled to the rectifier to receive the DC electricity; and an inverter coupled to the DC bus to convert the DC electricity to the AC electric power output regulated to the target frequency. 18. The system of claim 15, wherein the sampling arrangement includes means for periodically sampling the output to define the target duration to be approximately 25% of the waveform period. 19. The system of claim 15, further comprising an internal combustion engine providing mechanical power to operate the generator. 20. A method, comprising: operating an electric power generating device to provide an AC electricity output to a load at a target frequency, the device including an electric power generator; selecting a span of time less than one half of a waveform period for the target frequency; during the span of time, making a first magnitude measurement of the AC electricity output at a first time and second magnitude measurement of the AC electricity output at a second time after the first time; determining a zero crossing of the AC electricity output from the first magnitude measurement, the second magnitude measurement, and the target frequency; and regulating the electric power generating device in accordance with the zero crossing of the AC electricity output. 21. The method of claim 20, wherein the duration is approximately one quarter of the waveform period and the determining of the zero crossing includes: calculating a peak amplitude from the first magnitude measurement and the second magnitude measurement; and ascertaining the zero crossing based on the peak amplitude and the target frequency. 22. The method of claim 20, wherein the electric power generating device includes a controller and an inverter, the determining of the zero crossing includes calculating the zero crossing with the controller, and the regulating of the electric power generating device includes controlling the inverter with the controller. 23. The method of claim 20, wherein the controlling of the inverter targets a sinusoidal waveform for the AC electricity output. 24. The method of claim 23, wherein the generator is of a variable speed type, the device includes a rectifier coupled to the generator and the rectifier is coupled to the inverter by a direct current bus; and further comprising providing rotational mechanical power to the generator with an internal combustion engine. 25. The method of claim 23, wherein the determining of the zero crossing is performed with no more magnitude measurements than the first magnitude measurement and the second magnitude measurement during the span of time. 26. The method of claim 25, wherein the span of time is about one fourth of the waveform period and the output is at least approximately a sinusoidal waveform.