Electric compressor for vehicle

An electric compressor for a vehicle comprising:

• an electric motor having a coil;
• an inverter device that drives the electric motor;
• a capacitor that stores energy smaller than energy to be stored in the coil of the electric motor, is connected to an input end of the inverter device, and accumulates a charge according to an operation of the electric motor;
• a voltage detection device that detects a voltage of the capacitor;
• an abnormality determination device that determines an abnormality based on the voltage detected by the voltage detection device;
• a control device that performs a reflux mode in which the inverter device is controlled to flow back a current to the coil of the electric motor when the abnormality determination device determines the abnormality while the electric motor is in operation;
• and
• a current detection device that detects a current flowing through the electric motor, wherein:
• the control device maintains a voltage of the capacitor within a predetermined voltage range by an operation of the inverter device when a detection result of the current detection device is reduced to or below a predetermined current value after the reflux mode is performed.

An electric compressor for a vehicle comprising:

• an electric motor having a first-phase coil, a second-phase coil, and a third-phase coil;
• an inverter device that drives the electric motor, the inverter device having a first-phase arm, a second-phase arm, and a third-phase arm, each of the first-phase arm, the second-phase arm, and the third-phase arm being connected between a positive-electrode bus and a negative electrode bus connected to a battery and each having an upper switching element and a lower switching element connected in series, the upper switching element being connected to the positive-electrode bus and the lower switching element being connected to the negative electrode bus, a first intermediate point between the upper switching element of the first-phase arm being connected to the first-phase coil of the electric motor, a second intermediate point between the upper switching element of the second-phase arm being connected to the second-phase coil of the electric motor, and a third intermediate point between the upper switching element of the third-phase arm being connected to the third-phase coil of the electric motor;
• a capacitor that stores energy smaller than energy to be stored in the coils of the electric motor, is connected to an input end of the inverter device between the positive-electrode bus and the negative electrode bus, and accumulates a charge according to an operation of the electric motor;
• a voltage detection device that detects a voltage of the capacitor;
• an abnormality determination device that determines an abnormality based on the voltage detected by the voltage detection device;
• a control device that performs a regeneration prevention control to control the inverter device to shift to a reflux mode by switching off the upper switching elements of the first-phase arm, the second-phase arm, and the third-phase arm and by switching on the lower switching elements of the first-phase arm the first-phase arm, the second-phase arm, and the third-phase arm so that current flowing from the electric motor to the inverter device flows back to the coils of the electric motor in response to the abnormality determination device determining the abnormality while the electric motor is in operation;
• wherein the control device performs the regeneration prevention control to prevent the capacitor from being charged by regenerative power;
• and
• wherein the control device performs a discharge control, in addition to the regeneration prevention control, by discharging current from the capacitor to the control device, by discharging current from the capacitor to a discharge resistor connected in parallel to the capacitor, or by changing operation conditions of the control device.