| 摘要 |
<p>A dual-mode system for inexpensively operating electrically powered double-insulated devices (12), such as hand-held power tools and appliances. The system includes a cordless battery power module (14) that supplies the power and current demands of the device (12) in a cordless mode or a line power module (16) that supplies the necessary power and current demands in a physical envelope commensurate in size and interchangeable with that of the battery power module (14). The line power module (16) includes a chopper module (21) that is provided with a non-filtered high efficiency converter circuit that allows the chopper module (21) to generate the power and current required by the driven device (12). The inductance (22) of the motor (11) for the driven device (12) is used to filter the output of the chopper module (21). Eliminating the output filter from the chopper module (21) significantly reduces the cost and size of the line power module (16). Additionally, the need for multiple battery packs and fast rechargers is minimized by the availability of a low-cost converter. The line power module (16) includes an EMI filter (15) for filtering AC or DC input power. The chopper module (21) chops the filtered voltage, providing a series of voltage pulses having a DC voltage level that is suitable for driving the motor (11).</p> |
