Inverter device
View Patent ↗The inverter device contains the following structure: an inverter circuit which has upper-arm switching elements that are connected on a positive side of a DC power source and lower-arm switching elements that are connected on a negative side of the DC power source; a current sensor that detects current flowing between the DC power source and the inverter circuit; and a control circuit that controls the inverter circuit by a PWM driving so that the inverter circuit outputs AC current to the motor. The control circuit provides a carrier cycle with a first correction and provides the successive cycle with a second correction, by which the current sensor can detect phase current of the motor. A ripple current caused by the first correction and a ripple current caused by the second correction are opposite in polarity.
1. An inverter device comprising:
an inverter circuit having upper-arm switching elements connected on a positive side of a DC power source and lower-arm switching elements connected on a negative side of the DC power source;
a current sensor that detects current between the DC power source and the inverter circuit; and
a control circuit that controls the inverter circuit so that the inverter circuit outputs AC current to a motor by a PWM driving,
wherein, the control circuit provides a carrier cycle with a first correction and provides the successive cycle with a second correction on a basis of one carrier cycle or two carrier cycles so that the current sensor can detect phase current of the motor, and a ripple current caused by the first correction and a ripple current caused by the second correction are opposite in polarity.
2. The inverter device of claim 1 , wherein the current sensor detects current in two different phases of the motor on a basis of two carrier cycles.
3. The inverter device of claim 1 , wherein the current sensor detects current in two different phases of the motor on a basis of four carrier cycles.
4. The inverter device of claim 1 , wherein the control circuit makes an arrangement of carrier cycles in a manner that a carrier cycle without the first correction and the second correction is placed adjacent to a carrier cycle with the first correction or the second correction.
5. The inverter device of claim 4 , wherein the current sensor detects phase current when phase-current detection is possible in the carrier cycle without the first correction and the second correction.
6. The inverter device of claim 1 , wherein the phase current in two different phases is detected on a basis of the carrier cycle in start-up operations of the motor.
7. The inverter device of claim 1 , wherein the first correction and the second correction are carried out when the motor operates at low revolution speed.
8. The inverter device of claim 1 , wherein the first correction and the second correction are carried out when a low output is fed to the motor.
9. The inverter device according to claim 1 , the inverter device used in a structure where an input/output isolating transformer is disposed between the AC current and the motor.
10. An electric compressor comprising:
a compression mechanism;
a motor configured to drive the compression mechanism; and
an inverter device having:
an inverter circuit having upper-arm switching elements connected on a positive side of a DC power source and lower-arm switching elements connected on a negative side of the DC power source;
a current sensor that detects current between the DC power source and the inverter circuit; and
a control circuit that controls the inverter circuit by a PWM driving so that the inverter circuit outputs AC current to the motor,
wherein the control circuit provides a carrier cycle with a first correction and provides the successive cycle with a second correction on a basis of one carrier cycle or two carrier cycles so that the current sensor can detect phase current of the motor, and a ripple current caused by the first correction and a ripple current caused by the second correction are opposite in polarity.
11. A vehicle comprising:
a body forming an interior and at least one of an engine room and a motor room;
a wheel supporting the body;
an electric compressor having;
a compression mechanism;
a motor configured to drive the compression mechanism; and
an inverter device including:
an inverter circuit having upper-arm switching elements connected on a positive side of a DC power source and lower-arm switching elements connected on a negative side of the DC power source;
a current sensor that detects current between the DC power source and the inverter circuit; and
a control circuit that controls the inverter circuit by a PWM driving so that the inverter circuit outputs AC current to the motor,
wherein the control circuit provides a carrier cycle with a first correction and provides the successive cycle with a second correction on a basis of one carrier cycle or two carrier cycles so that the current sensor can detect phase current of the motor, and a ripple current caused by the first correction and a ripple current caused by the second correction are opposite in polarity;
an outdoor heat exchanger connected with the electric compressor and disposed in the engine room; and
an indoor heat exchanger connected with the electric compressor and disposed in the interior.