CT (Computed Tomography) test bulb tube

Abstract

A CT test bulb tube comprises a filament equivalent circuit, the input end of which inputs actual filament current flowing through a cathode filament when an actual CT bulb tube works, and the output end of which outputs equivalent voltage associated with the actual filament current; the incidence relation between the equivalent voltage and the actual filament current is determined by an actual resistance current curve of the cathode filament; the input end of the tube current equivalent circuit inputs the actual filament current, and the output end of the tube current equivalent circuit outputs equivalent tube current; the incidence relation between the equivalent tube current and the actual filament current is determined by the incidence relation between the actual tube current and the actual filament current when the actual CT bulb tube works. By adopting the CT test bulb tube, feedback data of an actual CT bulb tube can be output, and whether CT equipment abnormity is caused by the actual CT bulb tube or other reasons can be effectively judged.

Description

Technical Field

[0001] The invention relates to the technical field of medical equipment, and in particular to a CT test tube. Background Art

[0002] Computed Tomography (CT) is a medical imaging technology. CT imaging equipment (also known as CT equipment) uses X-ray beams to scan objects layer by layer and uses computer processing to produce detailed images of the internal structure of the object. The CT tube is a key component in the CT equipment, which is used to generate X-ray beams to detect objects. The performance of the CT tube directly affects the clarity of the resulting CT image and the stability of the CT equipment.

[0003] CT tubes operate in an environment of high temperature, high heat, high pressure, high vacuum, and high gravitational acceleration. During operation, there are many risks of failure, such as abnormal filament, abnormal vacuum, anode stall or jamming, etc. CT equipment also includes high-voltage generators, which also have the risk of failure and thus not being able to work properly. If an abnormality occurs in the CT equipment, 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 an abnormality in the CT tube causes an abnormality in the CT device.

[0005] In a first aspect, the present invention provides a CT test tube, comprising: a filament equivalent circuit, an input end of which inputs the actual filament current flowing through the cathode filament when the actual CT tube is working, and an output end of which 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; a tube current equivalent circuit, an input end of which inputs the actual filament current, and an output end of which outputs an 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.

[0006] Optionally, 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 the first input end of the first operational amplifier and the 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 the second end of the third resistor; the first control unit has an output end for coupling with the first end of the third resistor; the first control unit is suitable for controlling the first operational amplifier to output the equivalent voltage based on the actual filament current; the second resistor has a second end for grounding.

[0007] Optionally, the filament equivalent circuit also includes: a first transistor and a first diode, wherein: the first transistor 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 first diode has a cathode connected to ground.

[0008] Optionally, 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 has a first end for inputting the actual filament current, and a second end for coupling with the first input end of the second operational amplifier and the input end of the second control unit; the second operational amplifier has a second input end coupled with the fifth resistor, and an output end coupled with the first end of the sixth resistor; the second control unit has an output end coupled with the first end of the sixth resistor; and is suitable for controlling the second operational amplifier to output the equivalent tube current based on the actual filament current; the fifth resistor has a second end connected to ground.

[0009] Optionally, the tube current equivalent circuit also includes: a second triode and a second diode, wherein: the second triode has an emitter coupled to the output end of the second control unit, a base coupled to the first end of the sixth resistor, and a collector coupled to the output end of the second operational amplifier; the second diode has an anode coupled to the emitter of the second triode, and a cathode 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 transistor 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 comprises: an equivalent three-phase induction motor circuit, suitable for simulating the rotation speed value of the anode target disk in the actual CT tube.

[0013] Optionally, the equivalent three-phase induction motor circuit includes: 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, its first end 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 first equivalent inductor, its second end 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 equivalent resistor, its second end is coupled to the first end of the second equivalent inductor; the second equivalent inductor, its second end is coupled to the first end of the variable resistor; the third equivalent resistor, its The second end is coupled to the second end of the variable resistor; the third equivalent inductor, whose second end 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 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 core loss resistance value of the corresponding phase, and the inductance value of the third equivalent inductor is the 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, and 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. The actual resistance current curve of the cathode filament of the actual CT tube is simulated by the filament equivalent circuit. Thus, the failure of the actual CT tube due to the instability of the cathode filament at high temperature can be avoided. Based on the correlation between the actual filament current and the actual tube current, the equivalent tube current is simulated by the tube current equivalent circuit. The tube current equivalent circuit does not generate high heat, which can effectively avoid the CT tube from igniting while also avoiding high temperature and high heat. In addition, by using the filament equivalent circuit and the tube current equivalent circuit, it is not necessary to maintain a high vacuum in the tube core of the CT tube. Therefore, compared with the actual CT tube, the CT test tube does not need to work in a high temperature and high vacuum environment, so the failure of the CT test tube is greatly reduced. When the CT test tube is applied to the scene of CT equipment testing, the CT test tube can simulate the output data of the 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 structural schematic diagram of a CT test tube in an embodiment of the present invention;

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

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

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

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

[0021] Figure 6 Schematic diagram of an equivalent three-phase induction motor circuit in an embodiment of the present invention. DETAILED DESCRIPTION

[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 an embodiment of the present invention, the actual resistance current curve of the cathode filament of the actual CT tube is simulated by a filament equivalent circuit. Thus, the failure of the actual CT tube due to the instability of the cathode filament at high temperature can be avoided. Based on the correlation between the actual filament current and the actual tube current, the equivalent tube current is simulated by the tube current equivalent circuit. The tube current equivalent circuit does not generate high heat, which can effectively avoid the CT tube from igniting while also avoiding the high temperature and high heat. In addition, by using the filament equivalent circuit and the tube current equivalent circuit, it is not necessary to maintain a high vacuum in the tube core of the CT tube. Therefore, compared with the actual CT tube, the CT test tube does not need to work in a high temperature and high vacuum environment, so the failure of the CT test tube is greatly reduced. When the CT test tube is applied to the scene of CT equipment testing, the CT test tube can simulate the output data of the 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] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0025] The embodiment of the present invention provides a CT test tube, referring to Figure 1 .

[0026] like Figure 1 As shown, the CT test tube may include: a filament equivalent circuit 1, a tube current equivalent circuit 2. The CT test tube may also 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 circuit outlet 10, a temperature control switch 11, a cooling oil inlet 12, etc.

[0027] In a specific implementation, the 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 circuit outlet 10, temperature control switch 11, cooling oil inlet 12, etc. can use the corresponding structures in the actual CT tube, and the embodiment of the present invention does not modify the above structure.

[0028] In the embodiment of the present invention, the actual CT tube mentioned above is the CT tube actually used in the CT equipment. The CT test tube described below can simulate the working characteristic parameters of the actual CT tube when it is working normally. Under the same working conditions, its output data is the same 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 embodiment of the present invention can be equivalent to an actual CT tube. However, compared with the actual CT tube, the CT test tube in the embodiment of the present invention has been modified accordingly.

[0030] In actual applications, the cathode filament in the actual CT tube is made of metal tungsten, with a diameter of 0.2~0.3 mm and a length of 7~15 mm. The cathode filament heats up rapidly when the working current is 4~7 amps (A), and emits thermal electrons when the temperature is higher than 2500℃. By controlling the working current input to the cathode filament, the temperature of the cathode filament can be kept within a stable temperature range.

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

[0032] like Figure 2 As shown, a schematic diagram of the actual resistance-current curve of a cathode filament is given. Figure 2 In the figure, the horizontal axis is the actual filament current of the cathode filament, and the vertical axis 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 embodiment of the present invention, the equivalent voltage corresponding to the actual filament current can be simulated based on the actual resistance-current curve of the cathode filament through the filament equivalent circuit.

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

[0036] Reference Figure 3 , a structural schematic diagram of a filament equivalent circuit in an embodiment of the present invention is given.

[0037] In a 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, wherein:

[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] A second input terminal of the first operational amplifier OP1 is coupled to the second resistor R2, and an output terminal of the first operational amplifier OP1 is coupled to a second terminal of the third resistor R3;

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

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

[0042] In some embodiments, the first input terminal of the first operational amplifier OP1 is a positive input terminal “+”, and the second input terminal of the first operational amplifier OP1 is a negative input terminal “−”.

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

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

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

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

[0047] In actual applications, there is a tube voltage between the anode and cathode of the actual CT tube, and the tube voltage can reach 150kV. In the double-end high-voltage mode, the cathode of the CT tube is connected to a high voltage of -75kV, and the anode of the CT tube is connected to a high voltage of 75kV, so that the thermal electrons generated by the cathode filament are accelerated, bombarding the anode target to form a tube current and generate X-rays. The intensity of X-rays is related to the tube current. Under different tube voltages, the correlation between the actual filament current and the actual tube current is called the emission curve of the actual CT tube.

[0048] Reference Figure 4 , a schematic diagram of the mapping relationship between the actual filament current and the actual tube current is given, that is, a schematic diagram of the emission curve of the actual CT tube. Figure 4In the figure, the horizontal axis is the actual filament current, and the vertical axis 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 also increases accordingly.

[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 the 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, the equivalent tube current corresponding to the actual filament current can be obtained through the tube current equivalent circuit (the equivalent tube current is equal to the actual tube current).

[0051] Reference Figure 5 , a structural schematic 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, wherein:

[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] A second input terminal of the second operational amplifier OP2 is coupled to the fifth resistor R5, and an output terminal of the second operational amplifier OP2 is coupled to a first terminal 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] A second terminal of the fifth resistor R5 is grounded.

[0057] In some embodiments, the first input terminal of the second operational amplifier OP2 is a positive input terminal “+”, and the second input terminal of the second operational amplifier OP2 is a negative input terminal “−”.

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

[0059] The emitter of the second transistor N2 is coupled to the output terminal of the second control unit, the base of the second transistor N2 is coupled to the first terminal of the sixth resistor R6, and the collector of the second transistor N2 is coupled to the output terminal of the second operational amplifier OP2;

[0060] An anode of the second diode D2 is coupled to the emitter of the second transistor N2 , and a cathode of the second diode D2 is coupled to the collector of the second transistor N2 .

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

[0062] In a specific implementation, the sixth resistor R6 is an adjustable resistor, that is, the resistance value of the sixth resistor R6 is adjustable.

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

[0064] In addition, the actual CT tube is an electric vacuum device. In order to avoid sparking under high voltage and to facilitate the generation of actual tube current, that is, to avoid the electrons generated by the cathode filament from being blocked when transporting to the anode, a high vacuum needs to be maintained inside the tube core. Once the vacuum is destroyed or reduced, sparking or the cathode filament oxidation and melting risk will easily occur.

[0065] In the CT test tube provided by the embodiment of the present invention, an equivalent tube current associated with the actual filament current is generated through a tube current equivalent circuit, so high heat is not generated, high voltage is not required, and sparking is not likely to occur. Therefore, the CT test tube does not need a tube core in a high vacuum state, and ceramic with better insulation can be used to replace the tube core in a high vacuum state, which can more easily avoid the occurrence of sparking.

[0066] In actual applications, when the actual CT tube is working, the thermal electrons bombarding the anode target will generate huge heat. To avoid local high temperature, the anode target needs to rotate at high speed under the drive of the stator coil, and the speed can reach 8400 rpm~10500 rpm. However, due to the high gravitational acceleration at the gantry speed of the CT equipment, the bearing will be subject to higher resistance. In addition, as the temperature inside the actual CT tube increases, the driving force of the stator coil may also be affected, which in turn affects the speed of the anode target and causes the actual CT tube to fail.

[0067] The actual CT tube failure described in the embodiment of the present invention means that the actual CT tube cannot work normally, or the output data of the actual CT tube is abnormal data. The actual CT tube failure can also be referred to as an abnormality of the actual CT tube, a malfunction of the actual CT tube, etc.

[0068] Continue to refer to Figure 1 In the embodiment 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 may be used to simulate the rotation speed value of the anode target 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, 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:

[0070] A first end of the first equivalent resistor is coupled to a corresponding phase of a three-phase motor input line in an actual CT tube, and a second end of the first equivalent resistor is coupled to a first end of a 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 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 core loss resistance value of the corresponding phase, and the inductance value of the third equivalent inductor is the 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, and s is the slip rate of the actual three-phase induction motor.

[0077] Reference Figure 6 , a structural schematic diagram of an equivalent three-phase induction motor circuit in an embodiment of the present invention is given.

[0078] In a specific implementation, the A phase equivalent branch includes: a first equivalent resistor R A1 , the first equivalent inductance X A1 , the second equivalent resistance R A2 , the second equivalent inductance X A2 , the third equivalent resistance R A3 , the third equivalent inductance X A3 And the variable resistor R P1 ,in:

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

[0080] The first equivalent inductance X A1 The second end of the second equivalent resistor R A2 The first end of the third equivalent resistor R A3 The first end, the third equivalent inductance X A3 The first end of the first equivalent inductor X is coupled; A1 The inductance value is the inductance value of phase A of the motor stator coil;

[0081] The second equivalent resistance R A2 The second end and the second equivalent inductance X A2 The first end of the second equivalent resistor R A2 The resistance value is the resistance value of phase A when the motor rotor is converted to the stator side;

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

[0083] The third equivalent resistance R A3 The second end of the variable resistor R P1 The second end of the third equivalent resistor R A3 The resistance value is: the core loss resistance of phase A of the motor stator coil;

[0084] The third equivalent inductance X A2 The second end and the third equivalent resistor R A3The second end of the third equivalent inductor X A2 The inductance value is the magnetizing inductance value of the iron core of phase A of the motor stator coil;

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

[0086] In a specific implementation, the B-phase equivalent branch includes: a first equivalent resistor R B1 , the first equivalent inductance X B1 , the second equivalent resistance R B2 , the second equivalent inductance X B2 , the third equivalent resistance R B3 , the third equivalent inductance X B3 And the variable resistor R P2 ,in:

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

[0088] The first equivalent inductance X B1 The second end of the second equivalent resistor R B2 The first end of the third equivalent resistor R B3 The first end, the third equivalent inductance X B3 The first end of the first equivalent inductor X is coupled; B1 The inductance value is the inductance value of the motor stator coil phase B;

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

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

[0091] The third equivalent resistance R B3 The second end of the variable resistor R P2 The second end of the third equivalent resistor R B3The resistance value is: the core loss resistance of phase B of the motor stator coil;

[0092] The third equivalent inductance X B2 The second end and the third equivalent resistor R B3 The second end of the third equivalent inductor X B2 The inductance value is the magnetizing inductance value of the iron core of phase B of the motor stator coil;

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

[0094] In a specific implementation, the C phase equivalent branch includes: a first equivalent resistor 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 C3 , the third equivalent inductance X C3 And the variable resistor R P3 ,in:

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

[0096] The first equivalent inductance X C1 The second end of the second equivalent resistor R C2 The first end of the third equivalent resistor R C3 The first end, the third equivalent inductance X C3 The first end of the first equivalent inductor X is coupled; C1 The inductance value is the inductance value of the motor stator coil C phase;

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

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

[0099] The third equivalent resistance R C3 The second end of the variable resistor R P3 The second end of the third equivalent resistor R C3 The resistance value is: the core loss resistance of the C phase of the motor stator coil;

[0100] The third equivalent inductance X C2 The second end and the third equivalent resistor R C3 The second end of the third equivalent inductor X C2 The inductance value is the magnetizing inductance value of the C-phase iron core of the motor stator coil;

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

[0102] In a specific implementation, the adjustable resistance R of the A phase equivalent branch P1 The second end of the B phase equivalent branch is connected to the adjustable resistor R P2 The second end of the C phase equivalent branch has an adjustable resistor R P3 is coupled to the second end of .

[0103] In the embodiment of the present invention, the Figure 6 The equivalent three-phase induction motor circuit shown can simulate the feedback current output by the actual three-phase induction motor circuit by adjusting the slip rate of the motor. The feedback current is used to represent the actual rotation speed value of the anode target disk.

[0104] Therefore, by simulating the actual rotation speed value of the anode target disk through an equivalent three-phase induction motor circuit, it is possible to avoid failure of the actual CT tube caused by the rotation speed of the anode target disk being affected by high temperature.

[0105] In actual 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 is continuously loaded. When the temperature of the insulating oil rises, its volume will gradually increase. To avoid overheating and overpressure 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 triggered 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 the 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, Figure 1 In the embodiment, the CT test bulb tube may retain the temperature control switch 11 but not the pressure relief valve 6. Alternatively, the CT test bulb tube may 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, so it can avoid failures caused by filament abnormality, vacuum abnormality, anode stall or jamming, and can normally output the output data of the actual CT tube. Therefore, when an abnormality occurs in the CT device, the CT test tube can be used to replace the actual CT tube to eliminate the abnormality.

[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 does not have an abnormality, it can be determined that the abnormality of the CT device is caused by the actual CT tube. In this way, the efficiency of detecting the abnormal cause 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 shall 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; A tube current equivalent circuit, wherein the actual filament current is input into the input end thereof and the equivalent tube current is output from the output end thereof; 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.

2. The CT test tube according to claim 1, characterized in that: 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 the first input end of the first operational amplifier and the input end of the first control unit; The first operational amplifier has a second input terminal coupled to the second resistor and an output terminal coupled to the second terminal of the third resistor; The first control unit has an output terminal coupled to the first terminal 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; A second end of the second resistor is grounded.

3. The CT test tube according to claim 2, 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.

4. The CT test tube according to claim 1, characterized in that: 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 has a first end for inputting the actual filament current, and a second end for coupling with the first input end of the second operational amplifier and the input end of the second control unit; The second operational amplifier has a second input terminal coupled to the fifth resistor and an output terminal coupled to the first terminal of the sixth resistor; The second control unit, whose output end is coupled to the first end of the sixth resistor, is adapted to control the second operational amplifier to output the equivalent tube current based on the actual filament current; A second end of the fifth resistor is grounded.

5. The CT test tube according to claim 4, 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.

6. The CT test tube according to claim 5, 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.

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

8. The CT test tube according to claim 1, characterized in that: Also includes: 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.

9. The CT test tube according to claim 8, characterized in that: The equivalent three-phase induction motor circuit includes: 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 has a first end coupled to a corresponding phase of a three-phase motor input line in the actual CT tube, and a second end coupled to a first end of the first equivalent inductor; The first equivalent inductor, a second end of which 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 equivalent resistor, a second end of which is coupled to the first end of the second equivalent inductor; The second equivalent inductor, a second end of which is coupled to the first end of the variable resistor; The third equivalent resistor, a second end of which is coupled to the second end of the variable resistor; The third equivalent inductor, a second end of which 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 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 core loss resistance value of the corresponding phase, and the inductance value of the third equivalent inductor is the 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, and s is the slip rate of the motor.

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