Eaton Intelligent Power Limited

Youdong He

Huaqiang Li

Xiaoling Li

A variable frequency drive (VFD) circuit includes an input connectable to an AC source, a rectifier to convert an AC power input to a DC power, a DC link to receive DC power from the rectifier and having a DC link voltage thereon, a DC link capacitor bank with one or more capacitors connected to the DC link, and a pre-charge circuit coupled to the DC link capacitor. The pre-charge circuit further includes one or more resistors, one or more pre-charge relays each operable in on and off states to selectively control a current flow through the resistor(s) so as to control an initial pre-charge of the DC link capacitor, and an overvoltage relay operable in on and off states to selectively cut-off a current flow to the DC link capacitor bank, so as to prevent an overvoltage condition in the DC link capacitor bank.

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Shenzhen, China

Youdong He