Patent ID: 9214888
Filing Date: 2015-12-15
Classification: H02M,H02P

Abstract:
1. A pre-charging system for a capacitor in a voltage inverter for an electric motor, comprising: a microprocessor programmed to generate a first control signal; a pre-charging circuit operably coupled to the microprocessor, the pre-charging circuit having a counter circuit, a voltage pulse generating circuit, and a drive circuit; the counter circuit configured to generate a first plurality of voltage pulses, in response to the first control signal; the voltage pulse generating circuit configured to generate each voltage pulse of a second plurality of voltage pulses at a respective time interval while an instantaneous current flowing through a transistor and a pre-charging resistor electrically coupled to the capacitor is less than or equal to a threshold instantaneous current level; the drive circuit having the transistor and the pre-charging resistor electrically coupled to the transistor, the transistor configured to be electrically coupled between a high voltage terminal of a battery pack and the capacitor in the voltage inverter, the transistor configured to output a third plurality of voltage pulses in response to the second plurality of voltage pulses to increase a voltage across the capacitor in the voltage inverter; the counter circuit is further configured to count a number of voltage pulses of the first plurality of voltage pulses; and the counter circuit is further configured to generate a stop signal to induce the counter circuit to stop generating the first plurality of voltage pulses such that the pre-charging circuit stops charging the capacitor in the voltage inverter if the number of voltage pulses is greater than a predetermined number of voltage pulses indicating that the capacitor in the voltage inverter was not successfully pre-charged.