Patent ID: 9024468
Filing Date: 2015-05-05
Classification: B60L,G01R,Y02T

Abstract:
1. A driver circuit for an electric vehicle, comprising: a first voltage driver having a first input line, a first output line, and a power supply line; the first input line coupled to a microprocessor, the first output line coupled to a first side of a contactor coil of a contactor; an electrical current sensor electrically coupled to the power supply line, the electrical current sensor configured to generate a first signal indicating that an amount of electrical current flowing through the power supply line is greater than a threshold current level, the first signal being received by the microprocessor; a second voltage driver having a second input line and a second output line; the second input line coupled to the microprocessor, the second output line coupled to a second side of the contactor coil; the microprocessor configured to generate a first pulse width modulated signal on the first input line to induce the first voltage driver to output a second pulse width modulated signal on the first output line that is received by the first side of the contactor coil to energize the contactor coil; the microprocessor further configured to iteratively measure a voltage on a first side of a contact in the contactor over time to obtain a first plurality of voltage values; the microprocessor further configured to determine a first filtered voltage value based on the first plurality of voltage values; the microprocessor further configured to iteratively measure a voltage on a second side of the contact in the contactor over time to obtain a second plurality of voltage values; the microprocessor further configured to determine a second filtered voltage value based on the second plurality of voltage values; the microprocessor further configured to determine a difference value based on the first and second filtered voltage values; and the microprocessor further configured to stop generating the first pulse width modulated signal to de-energize the contactor coil if both the microprocessor receives the first signal from the electrical current sensor, and the difference value is greater than a predetermined threshold value, indicating that the first voltage driver is shorted to a ground voltage.