Driver circuit for an electric vehicle and a diagnostic method for determining when a voltage driver is shorted to a ground voltage

摘要

A driver circuit and a diagnostic method are provided. The driver circuit includes a first voltage driver, a second voltage driver, an electrical current sensor, and a microprocessor. The microprocessor iteratively measures voltages on first and second sides of a contact to obtain a first plurality of voltage values and a second plurality of voltage values. The microprocessor determines first and second filtered voltage values based on the first and second plurality of voltage values, respectively. The microprocessor determines a difference value based on the first and second filtered voltage values. The microprocessor de-energizes a contactor coil if a first signal from an electrical current sensor is received, and the difference value is greater than a predetermined threshold value.

主权项

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.