Motor drive device

摘要

The present invention relates to a motor drive device having a drive circuit for driving a power supply relay and a phase relay providing a fail-safe function. The motor drive device includes: an inverter circuit for supplying electric power to an electric motor; a power supply relay provided on a power supply line for supplying electric power from a power supply to the inverter circuit; a phase relay provided on a drive line between the inverter circuit and the electric motor, and constituted by a semiconductor switching element; and a drive circuit connected to the phase relay and the power supply relay. The phase relay and the power supply relay share the same drive circuit, and the phase relay and the power supply relay are driven simultaneously by a drive signal output from the drive circuit.

主权项

1. A motor drive device comprising:
an inverter circuit for supplying electric power to an electric motor; a power supply relay provided on a power supply line for supplying electric power from a power supply to the inverter circuit; a phase relay provided on a drive line between the inverter circuit and the electric motor, and constituted by a semiconductor switching element; a drive circuit connected to the phase relay and the power supply relay, for driving the phase relay and the power supply relay; a first control line connecting the drive circuit to the phase relay; a first surge-protection circuit provided at a position between the first control line and a motor-side line portion of the drive line connecting the electric motor to the phase relay, and configured to protect the phase relay from surge voltage; a first current reducing circuit configured to reduce a sneak current flowing from the electric motor into the first control line; a second control line connecting the drive circuit to the power supply relay; an electric charge accumulation element provided on an inverter-side line portion of the power supply line between the inverter circuit and the power supply relay, and configured to have a current supply capacity of the inverter circuit; a second surge-protection circuit connected at a position between the second control line and the inverter-side line portion; and a second current reducing circuit configured to reduce a sneak current flowing from the electric charge accumulation element into the second control line.