What is claimed is:
1. A protection circuit for power management semiconductor devices having a collector, a gate, and an emitter, the circuit comprising:
a first comparator which detects a collector voltage of said power management semiconductor device to output a fist detection signal when the detected collector voltage exceeds a first reference voltage;
a second comparator which detects a gate voltage of said power management semiconductor device to output a second detection signal, when the detected gate signal exceeds a second reference voltage which is a minimum gate voltage for feeding a rated power to said power management semiconductor device or over, and less than a line power voltage of a drive circuit for outputting a drive signal that drives said power management semiconductor device;
logic means for outputting a protection start signal when both the first and second detection signals are being outputted; and
gate voltage reduction means for reducing said gate voltage in accordance with the protection start signal from said logic means.
2. The protection circuit for power management semiconductor devices according to claim 1, wherein said second comparator detects said gate voltage based on a voltage separated by a separation resistance for separating a gate voltage of said power management semiconductor device.
3. The protection circuit for power management semiconductor devices according to claim 1, wherein said gate voltage reduction means cuts off a drive signal of said drive circuit and reduces said gate voltage such that it sequentially decreases.
4. The protection circuit for power management semiconductor devices according to claim 2, wherein said gate voltage reduction means cuts off a drive signal of said drive circuit and reduces said gate voltage such that it sequentially decreases.
5. The protection circuit for power management semiconductor devices according to claim 1, wherein the first reference voltage of said comparator is a collector voltage during the time when said power management semiconductor device is electrically continuous, or over, and less than a line power voltage of said drive circuit.
6. The protection circuit for power management semiconductor devices according to claim 2, wherein the first reference voltage of said comparator is a collector voltage during the time when said power management semiconductor device is electrically continuous, or over, and less than a line power voltage of said drive circuit.
7. The protection circuit for power management semiconductor devices according to claim 3, wherein the first reference voltage of said comparator is a collector voltage during the time when said power management semiconductor device is electrically continuous, or over, and less than a line power voltage of said drive circuit.
8. The protection circuit for power management semiconductor devices according to claim 4, wherein the first reference voltage of said comparator is a collector voltage during the time when said power management semiconductor device is electrically continuous, or over, and less than a line power voltage of said drive circuit.
9. The protection circuit for power management semiconductor devices according to claim 1, wherein said first comparator, second comparator, logic means, and gate voltage reduction means are formed in semiconductor integrated circuits together with said drive circuit.
10. The protection circuit for power management semiconductor devices according to claim 2, wherein said first comparator, second comparator, logic means, and gate voltage reduction means are formed in semiconductor integrated circuits together with said drive circuit.
11. A power converter for converting AC current to DC current, the converter comprising:
a power semiconductor device for converting DC current to AC current;
a power management semiconductor device which controls a switching operation of said power semiconductor device;
a first comparator which detects a collector voltage of said power management semiconductor device to output a fist detection signal when the detected collector voltage exceeds a first reference voltage;
a second comparator which detects a gate voltage of said power management semiconductor device to output a second detection signal when the detected gate signal exceeds a second reference voltage which is a minimum gate voltage for feeding a rated power to said power management semiconductor device or over, and less than a line power voltage of a drive circuit for outputting a drive signal that drives said power management semiconductor device;
logic means for outputting a protection start signal when both the first and second detection signals are being outputted;
gate voltage reduction means for reducing said gate voltage in accordance with the protection start signal from said logic means; and
computer processor means for controlling the ONOFF operation of said power management semiconductor device.
12. A hybrid electric vehicle having an internal combustion engine, an electric motor, a transmission for transmitting power from said internal combustion engine andor said electric motor to wheels, an inverter unit for converting DC power to AC power, and a DC power storage unit, wherein
said electric motor is an AC motor driven by AC power from said inverter unit, and
said inverter unit is the power converter according to claim 11.
13. An electric vehicle having an electric motor, a transmission for transmitting power from said electric motor to wheels, an inverter unit for converting DC power to AC power, and a DC power storage unit, wherein
said electric motor is an AC motor driven by AC power from said inverter unit, and
said inverter unit is the power converter according to claim 11.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A method for calculating a distance between consecutive two image frames obtained by moving a probe over a target to be examined, wherein the probe transmits and receives ultrasound signals, comprising the steps of:
a) producing a first main frame, a second main frame parallel to the first main frame, and a supplementary frame inclined at an angle with respect to the first main frame;
b) creating a virtual frame parallel to the first main frame by using the first main frame and the supplementary frame, wherein the virtual frame intersects the supplementary frame;
c) calculating a first correlation coefficient between the first main frame and the virtual frame;
d) computing a second correlation coefficient between the first and second main frames; and
e) calculating a first distance between the first main frame and the virtual frame to estimate a second distance between the first and second main frames by using the first distance and the first and second correlation coefficients.
2. The method of claim 1, wherein the probe is a 1.5 dimensional (1.5-D) probe made of a plurality of 1-D probes, wherein each 1-D probe consists of in-line transducers.
3. The method of claim 1, wherein the step e) includes:
e1) dividing the main frame and the virtual frame into a multiplicity of sub-frames, respectively; and
e2) estimating the second distance by using predetermined sub-frames among said multiplicity of sub-frames.
4. A method for producing a 3-D image of a target to be examined, comprising the steps of:
a) generating pairs of image frames by moving a probe over the target, wherein each pair includes a main frame and a supplementary frame inclined at an angle with respect to the main frame and the probe transmits and receives ultrasound signals;
b) creating a virtual frame of said each pair by using the main and supplementary frames of all the pairs, wherein the virtual frame is parallel to the main frame;
c) calculating a first correlation coefficient between the main frame and the virtual frame;
d) computing a second correlation coefficient between the main frame and a next main frame adjacent to the main frame;
e) estimating a first distance between the main frame and the next main frame by using a second distance between the main frame and the virtual frame and the first and second correlation coefficients;
f) repeating the steps a) to e) for the remaining main frames of the pairs; and
g) producing the 3-D image of the target by using the first distances for all the main frames of the pairs.
5. The method of claim 4, wherein the probe is a 1.5-D probe made of a plurality of 1-D probes, wherein each 1-D probe consists of in-line transducers.
6. The method of claim 4, wherein the step e) includes:
e1) dividing the main frame and the virtual frame into a multiplicity of sub-frames, respectively; and
e2) estimating the second distance by using predetermined sub-frames among said multiplicity of sub-frames.
7. The method of claim 6, wherein each of the predetermined sub-frames represents a speckle noise.
8. The method of claim 4, further comprising the steps of:
h) estimating a velocity of the probe at each of the main frames of the pairs;
i) comparing the probe velocity between the main frames to select main frames having a velocity difference over a predefined threshold; and
j) deleting the selected main frames in the production of the 3-D image of the target.
9. The method of claim 4, further comprising the steps of:
k) estimating a velocity of the probe at each of the main frames of the pairs;
l) selecting main frames having a difference of the probe velocity compared with that of an adjacent main frame over a predefined threshold; and
m) setting a distance between the selected main frames and the adjacent main frame to an average distance, wherein the average distance represents an average of distances between the main frames of the pairs.
10. A system for producing a 3-D image of a target to be examined, comprising:
a probe for generating pairs of image frames by moving a probe over the target, wherein each pair includes a main frame and a supplementary frame inclined at an angle with respect to the main frame and the probe transmits and receives the ultrasound signals;
means for calculating distances between the main frames of the pairs; and
means for displaying a 3-D image of the target produced by using the distances,
wherein the means for calculating the distances includes:
means for creating a virtual frame by using the main and supplementary frames, wherein the virtual frame is parallel to the main frame and intersects the supplementary frame;
means for calculating a first distance and a first correlation coefficient between the main frame and the virtual frame, and a second correlation coefficient between the main frame and an adjacent main frame; and
means for estimating a second distance between the main frame and the adjacent main frame by using the first distance and the first and second correlation coefficients.
11. The system of claim 10, wherein the probe is a 1.5-D probe made of a plurality of 1-D probes, wherein each 1-D probe consists of in-line transducers.