Power converter, X-ray CT apparatus, and X-ray imaging apparatus
View Patent ↗A power converter is configured to include an inverter which converts a DC output into an AC voltage of a predetermined frequency, and a high voltage generator which receives an output from output terminals of the inverter and boosts the output to a desired high DC voltage. The high voltage generator includes a transformer, and the primary windings of the transformer are connected to the output terminals of the inverter in parallel by conductive wires connected to both ends of each primary winding. Further, a current sensor is provided to detect a current flowing through each of the primary windings, and a control unit determines abnormalities of a path of the inverter and the primary windings on the basis of a value of the current sensor.
1. A power converter comprising:
an inverter which converts a DC output into an AC voltage of a predetermined frequency; and
a high voltage generator which receives an output from output terminals of the inverter and boosts the output to a desired high DC voltage,
wherein the high voltage generator includes a transformer having a primary winding and a secondary winding,
the number of primary windings is two or more,
the plurality of primary windings are connected to the output terminals of the inverter in parallel by conductive wires connected to both ends of each primary winding, and
a current sensor, which detects a current flowing through each of the plurality of primary windings, and a control unit, which determines abnormalities of a path of the inverter and the primary windings on the basis of a value of the current sensor, are provided.
2. The power converter according to claim 1 ,
wherein, when determining the abnormalities, the control unit determines that abnormalities have occurred, from the output of the current sensor, when a current of any of the plurality of primary windings does not flow or is smaller than current values of the other primary windings.
3. The power converter according to claim 1 ,
wherein, when determining the abnormalities, the control unit outputs a signal to stop the inverter to an inverter control unit that controls the inverter.
4. The power converter according to claim 2 ,
wherein the current sensor detects a current flowing into any of the plurality of primary windings and a current flowing from the different primary winding, and
the control unit calculates the difference between the amount of the two currents detected by the current sensor and determines that abnormalities have occurred when the difference exceeds a threshold value set in advance.
5. The power converter according to claim 2 ,
wherein the current sensor detects a current by calculating the difference between the amount of a current flowing into any of the plurality of primary windings and the amount of a current flowing from the different primary winding, and
the control unit determines that abnormalities have occurred when the current detected by the current sensor exceeds a threshold value set in advance.
6. The power converter according to claim 5 ,
wherein the current sensor is an AC current sensor which has a coil, in which both a conductive wire for supplying a current to any of the primary windings and a conductive wire for returning a current from the different primary winding are disposed in an inner space, and which detects a current flowing through the coil.
7. The power converter according to claim 4 ,
wherein, when the abnormalities are determined, on the basis of whether or not a current flows through any one of the plurality of primary windings, the control unit specifies a primary winding through which the current does not flow.
8. The power converter according to claim 5 ,
wherein, when the abnormalities are determined, on the basis of whether or not a current flows through any one of the plurality of primary windings, the control unit specifies a primary winding through which the current does not flow.
9. An X-ray CT apparatus comprising:
a disk having an opening through which an object is inserted;
an X-ray tube and an X-ray detector mounted at opposite positions with the opening of the disk interposed therebetween;
an X-ray high voltage device which supplies DC power to the X-ray tube;
a bed on which an object is placed and is inserted into the opening of the disk; and
a rotation driving unit that rotates the disk,
wherein the X-ray high voltage device includes the power converter according to claim 1 .
10. An X-ray imaging apparatus comprising:
an X-ray tube;
an X-ray image receiver which detects X-rays transmitted through an object; and
an X-ray high voltage device which supplies DC power to the X-ray tube,
wherein the X-ray high voltage device includes the power converter according to claim 1 .