CT test tube

Abstract

A CT test tube includes: a filament equivalent circuit, whose input end inputs the actual filament current flowing through the cathode filament during the actual operation of the CT tube, and whose output end outputs an equivalent voltage associated with the actual filament current; the association relationship between the equivalent voltage and the actual filament current is determined by the actual resistance-current curve of the cathode filament; a tube current equivalent circuit, whose input end inputs the actual filament current, and whose output end outputs an equivalent tube current; the association relationship between the equivalent tube current and the actual filament current is determined by the association relationship between the actual tube current and the actual filament current during the actual operation of the CT tube. By using the above CT test tube, the feedback data of the actual CT tube can be output, and it can effectively determine whether the abnormality of the CT device is caused by the actual CT tube or other reasons.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a CT test tube. Background Art

[0002] Computed Tomography (CT) is a medical imaging technology. A CT imaging device (also known as a CT device) uses an X-ray beam to perform tomographic scanning on an object and generates a detailed image of the internal structure of the object with the aid of computer processing. A CT tube is a key component in a CT device and is used to generate an X-ray beam for detecting an object. The performance of the CT tube directly affects the clarity of the obtained CT image and the stability of the CT device.

[0003] The CT tube operates in an environment of high temperature, high heat, high pressure, high vacuum, and high gravitational acceleration. During the operation process, there are many risks of failure, such as abnormal filament, abnormal vacuum degree, anode stall or jamming, etc. The CT device also includes a high-voltage generator, which also has the risk of failure and thus cannot work normally. If an abnormality occurs in the CT device, it is difficult to effectively distinguish whether the abnormality is caused by the CT tube or the high-voltage generator. Summary of the Invention

[0004] The purpose of the present invention is at least to provide a CT test tube that can output feedback data of an actual CT tube to determine whether the abnormality of the CT device is caused by the CT tube.

[0005] In a first aspect, the present invention provides a CT test tube, including: a filament equivalent circuit, whose input end inputs an actual filament current flowing through a cathode filament when an actual CT tube works, and whose output end outputs an equivalent voltage associated with the actual filament current; the association relationship between the equivalent voltage and the actual filament current is determined by an actual resistance-current curve of the cathode filament; a tube current equivalent circuit, whose input end inputs the actual filament current, and whose output end outputs an equivalent tube current; the association relationship between the equivalent tube current and the actual filament current is determined by the association relationship between an actual tube current and the actual filament current when the actual CT tube works.

[0006] Optionally, the filament equivalent circuit includes: a first resistor, a second resistor, a third resistor, a first operational amplifier, and a first control unit, where: for the first resistor, its first end inputs the actual filament current, and its second end is coupled to the first input end of the first operational amplifier and the input end of the first control unit; for the first operational amplifier, its second input end is coupled to the second resistor, and its output end is coupled to the second end of the third resistor; for the first control unit, its output end is coupled to the first end of the third resistor; the first control unit is adapted to control the first operational amplifier to output the equivalent voltage based on the actual filament current; for the second resistor, its second end is grounded.

[0007] Optionally, the filament equivalent circuit further includes: a first triode and a first diode, where: for the first triode, its emitter is coupled to the output end of the first control unit, its base is coupled to the first end of the third resistor, and its collector is coupled to the anode of the first diode; for the first diode, its cathode is grounded.

[0008] Optionally, the tube current equivalent circuit includes: a fourth resistor, a second control unit, a second operational amplifier, a fifth resistor, and a sixth resistor, where: for the fourth resistor, its first end inputs the actual filament current, and its second end is coupled to the first input end of the second operational amplifier and the input end of the second control unit; for the second operational amplifier, its second input end is coupled to the fifth resistor, and its output end is coupled to the first end of the sixth resistor; for the second control unit, its output end is coupled to the first end of the sixth resistor; it is adapted to control the second operational amplifier to output the equivalent tube current based on the actual filament current; for the fifth resistor, its second end is grounded.

[0009] Optionally, the tube current equivalent circuit further includes: a second triode and a second diode, where: for the second triode, its emitter is coupled to the output end of the second control unit, its base is coupled to the first end of the sixth resistor, and its collector is coupled to the output end of the second operational amplifier; for the second diode, its anode is coupled to the emitter of the second triode, and its cathode is coupled to the collector of the second triode.

[0010] Optionally, the tube current equivalent circuit further includes: a first adjustable capacitor, coupled between the collector of the second triode and the output end of the second operational amplifier.

[0011] Optionally, the sixth resistor is an adjustable resistor.

[0012] Optionally, the CT test tube further includes: an equivalent three-phase induction motor circuit, adapted to simulate the rotational speed value of the anode target disc in the actual CT tube.

[0013] Optionally, the equivalent three-phase induction motor circuit includes: an equivalent branch of phase A, an equivalent branch of phase B, and an equivalent branch of phase C. Any one of the equivalent branches includes: a first equivalent resistor, a first equivalent inductor, a second equivalent resistor, a second equivalent inductor, a third equivalent resistor, a third equivalent inductor, and a variable resistor, where: the first end of the first equivalent resistor is coupled to the corresponding phase of the three-phase motor input line in the actual CT tube, and its second end is coupled to the first end of the first equivalent inductor; the second end of the first equivalent inductor is coupled to the first end of the second equivalent resistor, the first end of the third equivalent resistor, and the first end of the third equivalent inductor; the second end of the second equivalent resistor is coupled to the first end of the second equivalent inductor; the second end of the second equivalent inductor is coupled to the first end of the variable resistor; the second end of the third equivalent resistor is coupled to the second end of the variable resistor; the second end of the third equivalent inductor is coupled to the second end of the third equivalent inductor; the resistance value of the first equivalent resistor is the resistance value of the corresponding phase of the motor stator coil in the actual CT tube; the inductance value of the first equivalent inductor is the inductance value of the corresponding phase of the motor stator coil; the resistance value of the second equivalent resistor is the resistance value of the corresponding phase when the motor rotor is reduced to the stator side, and the inductance value of the second equivalent inductor is the inductance value of the corresponding phase when the motor rotor is reduced to the stator side; the resistance value of the third equivalent resistor is the core loss resistance value of the corresponding phase, and the inductance value of the third equivalent inductor is the core magnetization inductance value of the corresponding phase; the resistance value of the variable resistor is: the product of the resistance value of the second equivalent resistor and a first quotient value, and the first quotient value is the quotient of (1 - s) and s, where s is the slip rate of the motor.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The CT test tube includes a filament equivalent circuit and a tube current equivalent circuit. Through the filament equivalent circuit, the actual resistance current curve of the cathode filament of the actual CT tube is simulated. Thus, the failure of the actual CT tube caused by the instability of the cathode filament at high temperatures can be avoided. Based on the correlation between the actual filament current and the actual tube current, the equivalent tube current is simulated through the tube current equivalent circuit. The tube current equivalent circuit does not generate high heat, and can effectively avoid the CT tube from arcing while also avoiding high temperatures and high heat. Moreover, by using the filament equivalent circuit and the tube current equivalent circuit, it is not necessary to maintain a high vacuum inside the tube core of the CT tube. Therefore, compared with the actual CT tube, the CT test tube does not need to operate in an environment of high temperature, high heat, and high vacuum, so the failure of the CT test tube is greatly reduced. When the CT test tube is applied to the scenario of CT equipment testing, the CT test tube can simulate the output data of a normal actual CT tube, so it can effectively distinguish whether the abnormality of the CT equipment is caused by the abnormality of the actual CT tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of a CT test tube in an embodiment of the present invention;

[0017] Figure 2 is a schematic diagram of the actual resistance current curve of a cathode filament;

[0018] Figure 3 is a schematic structural diagram of a filament equivalent circuit in an embodiment of the present invention;

[0019] Figure 4 is a schematic diagram of the mapping relationship between the actual tube current and the actual filament current;

[0020] Figure 5 is a schematic structural diagram of a tube current equivalent circuit in an embodiment of the present invention;

[0021] Figure 6 is a schematic structural diagram of an equivalent three-phase induction motor circuit in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] As described in the background art, if an abnormality occurs in a CT device, it is difficult to effectively distinguish whether the abnormality is caused by the CT tube or the high-voltage generator.

[0023] In the embodiments of the present invention, through the filament equivalent circuit, the actual resistance-current curve of the cathode filament of the actual CT tube is simulated. Thus, it is possible to avoid the failure of the actual CT tube caused by the instability of the cathode filament at high temperatures. Based on the correlation between the actual filament current and the actual tube current, the equivalent tube current is simulated through the tube current equivalent circuit. The tube current equivalent circuit does not generate high heat, and can effectively avoid the CT tube from arcing, while also avoiding the occurrence of high temperature and high heat. Moreover, by using the filament equivalent circuit and the tube current equivalent circuit, it is not necessary to maintain a high vacuum inside the tube core of the CT tube. Therefore, compared with the actual CT tube, the CT test tube does not need to operate in an environment of high temperature, high heat, and high vacuum, so the failure of the CT test tube is greatly reduced. When the CT test tube is applied to the scenario of CT equipment testing, the CT test tube can simulate the output data of a normal actual CT tube, so it can effectively distinguish whether the abnormality of the CT equipment is caused by the abnormality of the actual CT tube.

[0024] To make the above objects, features, and beneficial effects of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given with reference to the accompanying drawings.

[0025] Embodiments of the present invention provide a CT test tube, referring to Figure 1 .

[0026] As Figure 1 shown, the CT test tube may include: a filament equivalent circuit 1, a tube current equivalent circuit 2. The CT test tube may further include: a cathode high-voltage insulating ceramic head 4, a cathode high-voltage cable 5, a pressure relief valve 6, an anode high-voltage cable 7, an anode high-voltage insulating ceramic head 8, a three-phase motor input line 9, a cooling oil outlet 10, a temperature control switch 11, a cooling oil inlet 12, etc.

[0027] In a specific implementation, the above-mentioned cathode high-voltage insulating ceramic head 4, cathode high-voltage cable 5, pressure relief valve 6, anode high-voltage cable 7, anode high-voltage insulating ceramic head 8, three-phase motor input line 9, cooling oil outlet 10, temperature control switch 11, cooling oil inlet 12, etc. may follow the corresponding structures in the actual CT tube, and the embodiments of the present invention do not modify the above structures.

[0028] In the embodiments of the present invention, the above-mentioned actual CT tube is the CT tube actually used in the CT equipment. The following CT test tube can simulate the working characteristic parameters of the actual CT tube during normal operation, and under the same working conditions, its output data is the same as or almost the same as the output data of the actual CT tube.

[0029] That is to say, the CT test tube provided in the embodiments of the present invention can be equivalent to the actual CT tube. However, compared with the actual CT tube, the CT test tube in the embodiments of the present invention has been correspondingly modified.

[0030] In practical applications, the material of the cathode filament in an actual CT tube is tungsten metal. The wire diameter of the cathode filament is 0.2 - 0.3 millimeters (mm), and the length is 7 - 15 mm. When the working current of the cathode filament is 4 - 7 amperes (A), it heats up rapidly. When the temperature is higher than 2500 °C, it emits thermoelectrons. By controlling the working current input to the cathode filament, the temperature of the cathode filament can be maintained within a stable temperature range.

[0031] When the temperature of the cathode filament changes, the resistance of the cathode filament will change accordingly. Therefore, at different filament currents, there are corresponding resistances of the cathode filament.

[0032] As Figure 2 shown, a schematic diagram of the actual resistance - current curve of a cathode filament is given. Figure 2 In it, the abscissa is the actual filament current of the cathode filament, and the ordinate is the resistance value of the cathode filament. The actual filament current is the filament current on the cathode filament when the actual CT tube is working normally.

[0033] Based on Figure 2 it can be seen that as the current of the cathode filament increases, the temperature of the cathode filament rises, and the resistance of the cathode filament increases accordingly.

[0034] In the embodiments of the present invention, through the filament equivalent circuit, based on the actual resistance - current curve of the cathode filament, an equivalent voltage corresponding to the actual filament current can be simulated.

[0035] In specific implementation, when using a CT test tube, the actual filament current can be input to the input end of the filament equivalent circuit, and the equivalent voltage associated with the actual filament current can be output from the output end of the filament equivalent circuit. Since the quotient of the equivalent voltage and the actual filament current is the equivalent resistance of the cathode filament, therefore, based on the actual resistance - current curve of the cathode filament and the actual filament current of the cathode filament, the corresponding equivalent voltage can be determined.

[0036] Referring to Figure 3 , a schematic structural diagram of a filament equivalent circuit in the embodiments of the present invention is given.

[0037] In specific implementation, the filament equivalent circuit may include: a first resistor R1, a second resistor R2, a third resistor R3, a first operational amplifier OP1, and a first control unit, where:

[0038] The first end of the first resistor R1 inputs the actual filament current, and the second end of the first resistor R1 is coupled to the first input end of the first operational amplifier OP1 and the input end of the first control unit;

[0039] The second input terminal of the first operational amplifier OP1 is coupled to the second resistor R2, and the output terminal of the first operational amplifier OP1 is coupled to the second end of the third resistor R3;

[0040] The output terminal of the first control unit is coupled to the first end of the third resistor R3; the first control unit can control the output terminal of the first operational amplifier OP1 to output an equivalent voltage based on the actual filament current;

[0041] The second end of the second resistor R2 is grounded.

[0042] In some embodiments, the first input terminal of the first operational amplifier OP1 is the positive input terminal "+", and the second input terminal of the first operational amplifier OP1 is the negative input terminal "-".

[0043] In a specific implementation, the filament equivalent circuit may further include: a first triode N1 and a first diode D1, where:

[0044] The emitter of the first triode N1 is coupled to the output terminal of the first control unit, the base of the first triode N1 is coupled to the first end of the third resistor R3, and the collector of the first triode N1 is coupled to the anode of the first diode D1;

[0045] The cathode of the first diode D1 is grounded.

[0046] In summary, through the filament equivalent circuit, the actual resistance current curve of the cathode filament of the actual CT tube is simulated. Since the CT test tube is only used for testing and does not need to emit thermoelectrons, the equivalent circuit does not need to be in a high-temperature state like the cathode filament. Thus, the CT test tube can avoid failure caused by the instability of the cathode filament at high temperatures.

[0047] In practical applications, there is a tube voltage between the anode and the cathode of the actual CT tube, and the tube voltage can reach 150 kV. In the double-ended high-voltage mode, the cathode of the CT tube is connected to a high voltage of -75 kV, and the anode of the CT tube is connected to a high voltage of 75 kV. Thus, the thermoelectrons generated by the cathode filament are accelerated and bombarded on the anode target disk to form a tube current and generate X-rays. The intensity of the X-rays is related to the magnitude of the tube current. The correlation between the actual filament current and the actual tube current under different tube voltages is called the emission curve of the actual CT tube.

[0048] Refer to Figure 4 , which gives a schematic diagram of the mapping relationship between the actual filament current and the actual tube current, that is, a schematic diagram of the emission curve of the actual CT tube. Figure 4In the figure, the abscissa is the actual filament current, and the ordinate is the actual tube current. Under different tube voltages, the mapping relationship between the actual filament current and the actual tube current may be different. Under different tube voltages, as the actual filament current increases, the actual tube current correspondingly increases.

[0049] In an embodiment of the present invention, a tube current equivalent circuit is provided. The input end of the tube current equivalent circuit can input the actual filament current, and the output end of the tube current equivalent circuit outputs an equivalent tube current. The correlation between the equivalent tube current and the actual filament current can be determined by the correlation between the actual tube current and the actual filament current.

[0050] Specifically, the correlation between the actual tube current and the actual filament current can be used as the correlation between the equivalent tube current and the actual filament current. Thus, through the tube current equivalent circuit, the equivalent tube current corresponding to the actual filament current can be obtained (the equivalent tube current is equal to the actual tube current).

[0051] Referring to Figure 5 , a schematic structural diagram of a tube current equivalent circuit in an embodiment of the present invention is given.

[0052] In a specific implementation, the tube current equivalent circuit includes: a fourth resistor R4, a second control unit, a second operational amplifier OP2, a fifth resistor R5, and a sixth resistor R6, where:

[0053] The first end of the fourth resistor R4 inputs the actual filament current, and the second end of the fourth resistor R4 is coupled to the first input end of the second operational amplifier OP2 and the input end of the second control unit;

[0054] The second input end of the second operational amplifier OP2 is coupled to the fifth resistor R5, and the output end of the second operational amplifier OP2 is coupled to the first end of the sixth resistor R6;

[0055] The output end of the second control unit is coupled to the first end of the sixth resistor R6; the second control unit is adapted to control the second operational amplifier OP2 to output an equivalent tube current based on the actual filament current;

[0056] The second end of the fifth resistor R5 is grounded.

[0057] In some embodiments, the first input end of the second operational amplifier OP2 is the positive input end "+", and the second input end of the second operational amplifier OP2 is the negative input end "-".

[0058] In a specific implementation, the tube current equivalent circuit may further include a second triode N2 and a second diode D2, where:

[0059] The emitter of the second triode N2 is coupled to the output terminal of the second control unit. The base of the second triode N2 is coupled to the first end of the sixth resistor R6. The collector of the second triode N2 is coupled to the output terminal of the second operational amplifier OP2.

[0060] The anode of the second diode D2 is coupled to the emitter of the second triode N2. The cathode of the second diode D2 is coupled to the collector of the second triode N2.

[0061] In a specific implementation, the tube current equivalent circuit may further include a first adjustable capacitor C1. The first adjustable capacitor C1 may be coupled between the collector of the second triode N2 and the output terminal of the second operational amplifier OP2.

[0062] In a specific implementation, the above-mentioned sixth resistor R6 is an adjustable resistor. That is to say, the resistance value of the sixth resistor R6 is adjustable.

[0063] In practical applications, it can be known that the structure between the cathode and the anode of an actual CT tube is relatively complex. When a high voltage is connected between the cathode and the anode of an actual CT tube, a sparking phenomenon is likely to occur. When the thermoelectrons generated by the cathode filament are accelerated between the cathode and the anode and bombard the anode target disc, a huge amount of heat will be generated. The high heat will affect the stability of the actual CT tube, such as affecting the anode bearing and the vacuum degree inside the tube core, and it is more likely to occur a sparking phenomenon.

[0064] Moreover, an actual CT tube belongs to an electro-vacuum device. In order to avoid the occurrence of sparking under high voltage as much as possible and facilitate the generation of actual tube current, that is, to prevent the electrons generated by the cathode filament from being blocked during the transport to the anode, a high vacuum needs to be maintained inside the tube core. Once the vacuum is damaged or reduced, there will be a risk of easy occurrence of sparking phenomenon or oxidation and fusing of the cathode filament.

[0065] In the CT test tube provided by the embodiment of the present invention, through the tube current equivalent circuit, an equivalent tube current associated with the actual filament current is generated. Therefore, no high heat will be generated, no high voltage is required, and it is not easy to occur a sparking phenomenon. Therefore, the CT test tube does not need a tube core in a high vacuum state either. A ceramic with better insulation can be used to replace the tube core in a high vacuum state, and it is easier to avoid the occurrence of sparking phenomenon.

[0066] In practical applications, when an actual CT tube is working, the thermoelectrons bombarding the anode target disc will generate a huge amount of heat. To avoid local high temperature, the anode target disc needs to rotate at a high speed driven by the stator winding, and the rotation speed can reach 8400 revolutions per minute to 10500 revolutions per minute. However, affected by the high gravitational acceleration under the rotation speed of the CT equipment rack, the bearing will bear higher resistance. And as the temperature inside the actual CT tube rises, the driving force of the stator winding may also be affected, which will in turn affect the rotation speed of the anode target disc, resulting in the failure of the actual CT tube.

[0067] In the embodiments of the present invention, the actual failure of the CT tube means that the actual CT tube cannot work properly, or the output data of the actual CT tube is abnormal data. The actual failure of the CT tube can also be referred to as the actual CT tube having an abnormality, the actual CT tube having a fault, etc.

[0068] Continue to refer to Figure 1 , in the embodiments of the present invention, the CT test tube may further include an equivalent three-phase induction motor circuit 3. The equivalent three-phase induction motor circuit 3 can be used to simulate the rotational speed value of the anode target disc in the actual CT tube.

[0069] In a specific implementation, the equivalent three-phase induction motor circuit may include: an A-phase equivalent branch, a B-phase equivalent branch, and a C-phase equivalent branch. Any one of the equivalent branches includes: a first equivalent resistor, a first equivalent inductor, a second equivalent resistor, a second equivalent inductor, a third equivalent resistor, a third equivalent inductor, and a variable resistor, where:

[0070] The first end of the first equivalent resistor is coupled to the corresponding phase of the three-phase motor input line in the actual CT tube, and the second end of the first equivalent resistor is coupled to the first end of the first equivalent inductor;

[0071] The second end of the first equivalent inductor is coupled to the first end of the second equivalent resistor, the first end of the third equivalent resistor, and the first end of the third equivalent inductor;

[0072] The second end of the second equivalent resistor is coupled to the first end of the second equivalent inductor;

[0073] The second end of the second equivalent inductor is coupled to the first end of the variable resistor;

[0074] The second end of the third equivalent resistor is coupled to the second end of the variable resistor;

[0075] The second end of the third equivalent inductor is coupled to the second end of the third equivalent inductor.

[0076] In a specific implementation, the resistance value of the first equivalent resistor is the resistance value of the corresponding phase of the motor stator coil in the actual CT tube; the inductance value of the first equivalent inductor is the inductance value of the corresponding phase of the motor stator coil; the resistance value of the second equivalent resistor is the resistance value of the corresponding phase when the motor rotor is referred to the stator side, and the inductance value of the second equivalent inductor is the inductance value of the corresponding phase when the motor rotor is referred to the stator side; the resistance value of the third equivalent resistor is the core loss resistance value of the corresponding phase, and the inductance value of the third equivalent inductor is the core magnetization inductance value of the corresponding phase; the resistance value of the variable resistor is: the product of the resistance value of the second equivalent resistor and the first quotient value, and the first quotient value is the quotient of (1 - s) and s, where s is the slip ratio of the actual three-phase induction motor.

[0077] Refer toFigure 6 shows a schematic structural diagram of an equivalent three-phase induction motor circuit in an embodiment of the present invention.

[0078] In a specific implementation, the A-phase equivalent branch includes: a first equivalent resistor R A1 , a first equivalent inductor X A1 , a second equivalent resistor R A2 , a second equivalent inductor X A2 , a third equivalent resistor R Ac , a third equivalent inductor X Am and a variable resistor R P1 , where:

[0079] The first end of the first equivalent resistor R A1 is coupled to the U phase of the three-phase motor input line, and the second end of the first equivalent resistor R A1 is coupled to the first end of the first equivalent inductor X A1 ; the resistance value of the first equivalent resistor R A1 is the resistance value of the A-phase of the motor stator coil in the actual CT tube;

[0080] The second end of the first equivalent inductor X A1 is coupled to the first end of the second equivalent resistor R A2 , the first end of the third equivalent resistor R Ac , and the first end of the third equivalent inductor X Am ; the inductance value of the first equivalent inductor X A1 is the inductance value of the A-phase of the motor stator coil;

[0081] The second end of the second equivalent resistor R A2 is coupled to the first end of the second equivalent inductor X A2 ; the resistance value of the second equivalent resistor R A2 is the resistance value of the A-phase when the motor rotor is referred to the stator side;

[0082] The second end of the second equivalent inductor X A2 is coupled to the first end of the variable resistor R P1 ; the inductance value of the second equivalent inductor X A2 is the inductance value of the A-phase when the motor rotor is referred to the stator side;

[0083] The second end of the third equivalent resistor R Ac is coupled to the second end of the variable resistor R P1 ; the resistance value of the third equivalent resistor R Ac is: the core loss resistance value of the A-phase of the motor stator coil;

[0084] The second end of the third equivalent inductor X Am is coupled to the second end of the third equivalent resistor R Acis coupled to the second end; the third equivalent inductor X Am The inductance value of is the core magnetization inductance value of phase A of the motor stator coil;

[0085] Variable resistor R P1 The resistance value of is: the second equivalent resistor R A2 multiplied by (1 - s) / s, where s is the slip ratio of the motor.

[0086] In a specific implementation, the B-phase equivalent branch includes: the first equivalent resistor R B1 , the first equivalent inductor X B1 , the second equivalent resistor R B2 , the second equivalent inductor X B2 , the third equivalent resistor R Bc , the third equivalent inductor X Bm and the variable resistor R P2 , where:

[0087] The first end of the first equivalent resistor R B1 is coupled to the U phase of the three-phase motor input line, and the second end of the first equivalent resistor R B1 is coupled to the first end of the first equivalent inductor X B1 ; the resistance value of the first equivalent resistor R B1 is the resistance value of phase B of the motor stator coil in the actual CT tube;

[0088] The second end of the first equivalent inductor X B1 is coupled to the first end of the second equivalent resistor R B2 , the first end of the third equivalent resistor R Bc , and the first end of the third equivalent inductor X Bm ; the inductance value of the first equivalent inductor X B1 is the inductance value of phase B of the motor stator coil;

[0089] The second end of the second equivalent resistor R B2 is coupled to the first end of the second equivalent inductor X B2 ; the resistance value of the second equivalent resistor R B2 is the resistance value of phase B when the motor rotor is referred to the stator side;

[0090] The second end of the second equivalent inductor X B2 is coupled to the first end of the variable resistor R P2 ; the inductance value of the second equivalent inductor X B2 is the inductance value of phase B when the motor rotor is referred to the stator side;

[0091] The second end of the third equivalent resistor R Bc is coupled to the second end of the variable resistor R P2 ; the second end of the third equivalent resistor R BcThe resistance value is: the core loss resistance value of phase B of the motor stator coil;

[0092] The third equivalent inductance X Bm The second end of is coupled to the third equivalent resistance R Bc The second end of; The third equivalent inductance X Bm The inductance value of is the core magnetization inductance value of phase B of the motor stator coil;

[0093] The variable resistance R P2 The resistance value of is: the second equivalent resistance R B2 The resistance value of multiplied by (1 - s) / s, where s is the slip ratio of the motor.

[0094] In a specific implementation, the C-phase equivalent branch includes: the first equivalent resistance R C1 , the first equivalent inductance X C1 , the second equivalent resistance R C2 , the second equivalent inductance X C2 , the third equivalent resistance R Cc , the third equivalent inductance X Cm and the variable resistance R P3 , where:

[0095] The first end of the first equivalent resistance R C1 is coupled to the U phase of the three-phase motor input line, and the second end of the first equivalent resistance R C1 is coupled to the first end of the first equivalent inductance X C1 ; The resistance value of the first equivalent resistance R C1 is the resistance value of phase C of the motor stator coil in the actual CT tube;

[0096] The second end of the first equivalent inductance X C1 is coupled to the first end of the second equivalent resistance R C2 , the first end of the third equivalent resistance R Cc , and the first end of the third equivalent inductance X Cm ; The inductance value of the first equivalent inductance X C1 is the inductance value of phase C of the motor stator coil;

[0097] The second end of the second equivalent resistance R C2 is coupled to the first end of the second equivalent inductance X C2 ; The resistance value of the second equivalent resistance R C2 is the resistance value of phase C when the motor rotor is referred to the stator side;

[0098] The second end of the second equivalent inductance X C2 is coupled to the first end of the variable resistance R P3 ; The inductance value of the second equivalent inductance X C2 is the inductance value of phase C when the motor rotor is referred to the stator side;

[0099] The third equivalent resistance R Cc The second end of is coupled to the variable resistor R P3 The second end of; the third equivalent resistance R Cc The resistance value of is: the core loss resistance value of the C-phase of the motor stator coil;

[0100] The third equivalent inductance X Cm The second end of is coupled to the second end of the third equivalent resistance R Cc The second end of; the third equivalent inductance X Cm The inductance value of is the core magnetization inductance value of the C-phase of the motor stator coil;

[0101] The variable resistor R P3 The resistance value of is: the resistance value of the second equivalent resistance R C2 Multiplied by (1 - s) / s, where s is the slip ratio of the motor in the actual CT tube.

[0102] In a specific implementation, the second end of the variable resistor R in the A-phase equivalent branch P1 Is coupled to the second end of the variable resistor R in the B-phase equivalent branch P2 The second end of, and the second end of the variable resistor R in the C-phase equivalent branch P3 Is coupled.

[0103] In an embodiment of the present invention, an equivalent three-phase induction motor circuit as shown in Figure 6 Is adopted. By adjusting the slip ratio of the motor, a feedback current output by the actual three-phase induction motor circuit can be simulated, and this feedback current is used to represent the actual rotational speed value of the anode target disc.

[0104] Thus, by simulating the actual rotational speed value of the anode target disc through the equivalent three-phase induction motor circuit, the failure of the actual CT tube caused by the influence of high temperature on the rotational speed of the anode target disc can be avoided.

[0105] In practical applications, when the actual CT tube is working, the insulating oil used for cooling will heat up as the power of the actual CT tube continues to be loaded. When the temperature of the insulating oil rises, its volume will gradually increase. To avoid overheating and overvoltage of the actual CT tube, a temperature control switch can be set in the actual CT tube. When the temperature of the insulating oil exceeds the safe temperature, an alarm is given and the power loading of the actual CT tube is disconnected. The pressure relief valve opens to relieve pressure when the pressure threshold is reached.

[0106] In an embodiment of the present invention, since the CT test tube does not need to work in a high-pressure, high-temperature and high-heat environment, so in Figure 1 The CT test tube can retain the temperature control switch 11 and not retain the pressure relief valve 6. Or, the CT test tube can not retain the temperature control switch 11 and the pressure relief valve 6.

[0107] In summary, the CT test tube provided in the embodiment of the present invention does not need to work in an environment of high temperature, high heat, high pressure, high vacuum, and high gravitational acceleration. Therefore, it can avoid failures caused by abnormal filaments, abnormal vacuum degrees, anode stall or jamming, etc., and can normally output the output data of an actual CT tube. Therefore, when an abnormality occurs in a CT device, the CT test tube can be used to replace the actual CT tube, and then the abnormality can be eliminated.

[0108] After replacing the actual CT tube with the CT test tube, if the CT device still has an abnormality, it can be determined that the abnormality of the CT device is not caused by the actual CT tube; if the CT device has no abnormality, it can be determined that the abnormality of the CT device is caused by the actual CT tube. Thus, the detection efficiency of the cause of the abnormality of the CT device can be effectively improved.

[0109] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A CT test tube, characterized in that: include: A filament equivalent circuit, wherein an input end of the circuit inputs an actual filament current flowing through the cathode filament when the actual CT tube is working, and an output end of the circuit outputs an equivalent voltage associated with the actual filament current; The correlation between the equivalent voltage and the actual filament current is determined by the actual resistance current curve of the cathode filament; The filament equivalent circuit comprises: a first resistor, a second resistor, a third resistor, a first operational amplifier and a first control unit, wherein: the first resistor has a first end for inputting the actual filament current, and a second end for coupling with a first input end of the first operational amplifier and an input end of the first control unit; the first operational amplifier has a second input end for coupling with the second resistor, and an output end for coupling with a second end of the third resistor; the first control unit has an output end for coupling with a first end of the third resistor; the first control unit is adapted to control the first operational amplifier to output the equivalent voltage based on the actual filament current; the second end of the second resistor is grounded; A tube current equivalent circuit, whose input end inputs the actual filament current, and whose output end outputs the equivalent tube current; the correlation between the equivalent tube current and the actual filament current is determined by the correlation between the actual tube current and the actual filament current when the actual CT tube is working; the tube current equivalent circuit comprises: a fourth resistor, a second control unit, a second operational amplifier, a fifth resistor and a sixth resistor, wherein: the fourth resistor, whose first end inputs the actual filament current, and whose second end is coupled to the first input end of the second operational amplifier and the input end of the second control unit; the second operational amplifier, whose second input end is coupled to the fifth resistor, and whose output end is coupled to the first end of the sixth resistor; the second control unit, whose output end is coupled to the first end of the sixth resistor; is suitable for controlling the second operational amplifier to output the equivalent tube current based on the actual filament current; the second end of the fifth resistor is grounded; The equivalent three-phase induction motor circuit is suitable for simulating the rotation speed value of the anode target disk in the actual CT tube, including: an A-phase equivalent branch, a B-phase equivalent branch and a C-phase equivalent branch, wherein any phase equivalent branch includes: a first equivalent resistor, a first equivalent inductor, a second equivalent resistor, a second equivalent inductor, a third equivalent resistor, a third equivalent inductor and a variable resistor, wherein: the first equivalent resistor, a first end thereof is coupled to a corresponding phase of the three-phase motor input line in the actual CT tube, and a second end thereof is coupled to a first end of the first equivalent inductor; the first equivalent inductor, a second end thereof is coupled to a first end of the second equivalent resistor, a first end of the third equivalent resistor and a first end of the third equivalent inductor; the second equivalent resistor, a second end thereof is coupled to a first end of the second equivalent inductor; the second equivalent inductor, a second end thereof is coupled to a first end of the variable resistor; the third equivalent resistor, a second end thereof is coupled to a second end of the variable resistor; the first equivalent resistor, a second end thereof is coupled to a second end of the variable resistor; three equivalent inductors, the second end of which is coupled with the second end of the third equivalent inductor; the resistance value of the first equivalent resistor is the resistance value of the corresponding phase of the motor stator coil in the actual CT tube; the inductance value of the first equivalent inductor is the inductance value of the corresponding phase of the motor stator coil; the resistance value of the second equivalent resistor is the resistance value of the corresponding phase when the motor rotor is converted to the stator side, and the inductance value of the second equivalent inductor is the inductance value of the corresponding phase when the motor rotor is converted to the stator side; the resistance value of the third equivalent resistor is the iron core loss resistance value of the corresponding phase, and the inductance value of the third equivalent inductor is the iron core magnetizing inductance value of the corresponding phase; the resistance value of the variable resistor is: the product of the resistance value of the second equivalent resistor and the first quotient value, the first quotient value is the quotient of (1-s) and s, s is the slip rate of the motor; the second end of the variable resistor of the A-phase equivalent branch is coupled with the second end of the variable resistor of the B-phase equivalent branch and the second end of the variable resistor of the C-phase equivalent branch.

2. The CT test tube according to claim 1, characterized in that: The filament equivalent circuit further includes: a first triode and a first diode, wherein: The first triode has an emitter coupled to the output end of the first control unit, a base coupled to the first end of the third resistor, and a collector coupled to the anode of the first diode; The cathode of the first diode is grounded.

3. The CT test tube according to claim 1, characterized in that: The tube current equivalent circuit further includes: a second triode and a second diode, wherein: The second triode, whose emitter is coupled to the output end of the second control unit, whose base is coupled to the first end of the sixth resistor, and whose collector is coupled to the output end of the second operational amplifier; The second diode has an anode coupled to the emitter of the second transistor, and a cathode coupled to the collector of the second transistor.

4. The CT test tube according to claim 3, characterized in that: The tube current equivalent circuit further includes: a first adjustable capacitor coupled between the collector of the second transistor and the output end of the second operational amplifier.

5. The CT test tube according to claim 3, characterized in that: The sixth resistor is an adjustable resistor.

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