智能電表的電源設(shè)計(jì)

　　智能電表的電源設(shè)計(jì)者面臨著一系列的問(wèn)題。他們不僅需要考慮諸如能源效率之類(lèi)的典型問(wèn)題，而且如果供電失敗，也需要考慮諸如欺詐和正確操作等問(wèn)題。

　　從低功率水平運(yùn)行的能力是重要的。只有智能電表有豪華的電網(wǎng)電源，即使在這種情況下，消費(fèi)必須盡量減少，因?yàn)檫\(yùn)行設(shè)備的權(quán)力來(lái)自實(shí)用程序，而不是從客戶(hù)。另一方面，燃?xì)夂退硇枰軌驈碾姵剡\(yùn)行，并保證壽命為十年或更長(zhǎng)時(shí)間。這嚴(yán)重制約了功率變換器的效率以及剩余的儀表電子學(xué)。

　　同時(shí)，這些新型儀表需要能夠支持32位微處理器和更大的內(nèi)存大小，以便它們能夠提供加密功能，以及通過(guò)無(wú)線通信進(jìn)行更細(xì)粒度的使用測(cè)量和數(shù)據(jù)更新。如果外部電源故障，電表需要能夠發(fā)送通知給公用事業(yè)，要求使用后備能源戰(zhàn)略。

　　Tampering is one key problem that smart meter designers have to face. One method used on electricity meters is to disrupt the measurements taken by current transformers that are used to measure alternating current （AC）。 As a transformer， this sensor has a primary winding， a magnetic core， and a secondary winding. The AC flowing in the primary produces an AC in the secondary， which can be measured by the meter using a shunt resistor.

　　The transformer used for current sensing can， with relative ease， be saturated using strong rare-earth metal magnets， preventing the meter from sensing the change in current. As a result， the transformers are now often shielded. However， would-be fraudsters may still try to tamper with the meter and， without realizing it， damage the power supply circuitry.