| 摘要 |
A method and apparatus for charging a bulk energy storage capacitor, such as used for actuating solenoids in downhole tools. An electrical generator, which may be a mud-powered, provides a rectified voltage proportional to its rotational speed. The rectified voltage is fed to a single-ended primary-inductor converter, which in turn charges the bulk capacitor 16 when the voltage across the bulk capacitor falls between predetermined upper and lower set points. Upon discharging the bulk capacitor, such as from actuation of solenoid valves for creating mud pressure pulses, control logic also causes the converter to cease charging the bulk capacitor 16 to enhance circuit efficiency and performance. A battery may also be provided to charge the bulk capacitor via a current limiter, and a disconnect circuit prevents the battery from charging the bulk capacitor when the generator is charging the bulk capacitor via the converter. |
