Ray tube training method and power generator

Abstract

The invention belongs to the technical field of X-ray tube control methods, and particularly provides a ray tube training method and a power generator. The ray tube training method specifically comprises the following steps: acquiring the last working date and time of a ray tube and the type of the ray tube; confirming that the preheating time of the ray tube is long, and setting a starting time function and an ending time function of ray preheating; determining basic parameters of the ray tube; deriving the final preheating power of the ray tube; drawing a curve; and executing ray tube training operation. A power generator comprises a main loop and a control loop, the control loop is used for controlling the main loop, and the control loop operates based on the PID control theory. According to the scheme, a PID (Proportion Integration Differentiation) control principle is adopted in a tube voltage and tube current control method to form a double-closed-loop feedback control system, so that accidental overshoot and oscillation of the control system are prevented; and obtaining a training machine power supply curve according to the intersection area of the curve, and smoothly and continuously supplying power according to the curve.

Description

Technical Field

[0001] The invention belongs to the technical field of X-ray tube control methods, and in particular provides a ray tube training method and a power generator. Background Art

[0002] Training is the pre-startup operation of the X-ray tube. Figure 4 , U is the tube voltage, U a is the filament voltage, I a is the filament current, I is the tube current, W in is the coolant inflow, W out To cool the liquid out, the X-ray tube produces X-rays by ionization, also known as ionizing radiation, which means that the filament ionizes electrons, which are accelerated to the plate, and then reflected by the plate through the focus to the lead hole (focus) and radiate out to form X-rays.

[0003] CT machines, DR machines and other X-ray tube-based imaging equipment need to be trained when they are shut down and restarted to ensure that the X-ray tube is in the best condition during the formal imaging process.

[0004] Most power generators on the market are mainly composed of a main circuit (including a rectifier unit, a filter unit, an inverter unit, a transformer unit and a voltage doubler rectifier unit, the input circuit is sequentially connected to the rectifier unit, the filter unit, the inverter unit, the transformer unit and the voltage doubler rectifier unit, and the voltage doubler rectifier unit is electrically connected to the X-ray tube via the output circuit), a control circuit and software. The control circuit part is prone to overshoot in the tube current control due to the lack of closed-loop control during use, causing equipment damage. At the same time, due to its software and design limitations, it can only use a segmented method to set the power curve. Figure 5 , the same output current is used for power supply within a power range, and the X-ray tube cannot reach the optimal operating power within the range under this current. There are also loopholes in the training control logic of this type of power generator. The training function cannot be paused after it is started (suddenly pausing the training operation, the X-ray tube loses power, which may pose a safety hazard), and there is no restriction on forced training when the X-ray tube is shut down for a long time (generally limited to 72 hours, equipment shutdown for more than 72 hours is a long shutdown, equipment shutdown for less than 72 hours is a short shutdown, and equipment shutdown for less than 8 hours does not require training), resulting in a high failure rate of the shooting equipment. Summary of the invention

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for training a ray tube, the specific process is as follows:

[0006] Step 1, obtaining the last X-ray tube working date and time and the X-ray tube type;

[0007] Step 2: confirm that the preheating time of the X-ray tube is t, and assume that the start time of the radiation preheating is T1 and the end time is T2, T2 = T1 + t;

[0008] Step 3: Confirm the basic parameters of the X-ray tube;

[0009] Step 4: derive the final preheating power of the X-ray tube;

[0010] Step 5, draw a curve of the tube voltage of the X-ray tube changing with time;

[0011] Step 6: Draw a curve of the tube current of the X-ray tube changing with time;

[0012] Step 7: Draw the tube power curve of the X-ray tube;

[0013] P=U·I

[0014] Where P is the preheating tube power, U is the preheating tube voltage, and I is the preheating tube power;

[0015] Step 8: Perform the X-ray tube training operation;

[0016] According to the above curve dynamics, the power supply parameters of the power generator are adjusted in real time until the training time reaches time T2, and the training is completed.

[0017] Furthermore, in step one, recording the last working date and time of the ray tube is a basic function of the ray tube control system. The ray tube type is the model of the ray tube installed on the current device. The ray tubes used on the market are generally standardized devices, and the basic parameters of the ray tube can be obtained by looking up the table.

[0018] Furthermore, in step 3, the basic parameters specifically include the maximum preheating tube voltage U max , Maximum preheating tube current I max , Maximum preheating power P max , Preheating starting tube voltage U s and preheating starting tube current I s .

[0019] Furthermore, in step 4, the final preheating power of the X-ray tube is P over ;

[0020] P over =P MAX ·K p ;

[0021] In the formula, K p is the preheating power percentage, the theoretical value is between 0 and 100%. The power used by the power generator is calculated based on the radiation intensity required for this shooting task, K p = Power used / maximum power of power generator.

[0022] Furthermore, in step 5, according to the formula:

[0023] U=U s ·log 10 (10P t +a);

[0024] P t =t i / t;

[0025] Where, U is the preheating tube voltage, U s is the preheating starting tube voltage, P t is the ratio of preheating timing time to tube preheating time, a is a constant describing the leading amount of the preheating voltage rising trend (obtained by looking up the table), t i is the time interval between a single sampling cycle, T C The current time T of the X-ray tube preheating C =T1+t i ;

[0026] With a fixed sampling period, take multiple different T C Substituting numerical values ​​into the formula, we can obtain multiple discrete points that express the relationship between time and tube voltage. We use a smooth curve to connect the discrete points to form a curve of tube voltage changing with time.

[0027] Further, in step 6, the tube voltage U max As the dividing point, the X-ray tube current curve is divided into two parts;

[0028] When the tube voltage rises to U max Previously, it was obtained according to the following formula:

[0029] I=I s ;

[0030] When the tube voltage rises to U max Then, according to the following formula:

[0031] I=t i ·K+I s ;

[0032] K=P over / U over / t i ;

[0033] Where, I is the preheating tube current, I s is the preheating starting tube current, I s To preheat the starting tube current;

[0034] With a fixed sampling period, take multiple different t iSubstituting numerical values ​​into the formula, we can obtain multiple discrete points that express the relationship between time and tube current. We connect the discrete points with a smooth curve to form a curve of tube current changing with time.

[0035] A power generator comprises a main circuit and a control circuit, wherein the control circuit is used to control the main circuit;

[0036] The main circuit includes a rectifier unit, a filter unit, an inverter unit, a transformer unit and a voltage-doubling rectifier unit. The input circuit is sequentially connected to the rectifier unit, the filter unit, the inverter unit, the transformer unit and the voltage-doubling rectifier unit. The voltage-doubling rectifier unit is electrically connected to the ray tube via the output circuit.

[0037] The control loop operates based on PID control theory and is used to control the main loop.

[0038] Furthermore, the control circuit has a built-in independent timing unit, and the timing unit is directly associated with the main circuit, and a duration value of the forced training is preset.

[0039] The beneficial effects of using the present invention are:

[0040] This solution adopts the PID control principle in the control method of tube voltage and tube current to form a double closed-loop feedback control system, which can prevent accidental overshoot to ensure equipment safety and prevent control system oscillation from causing X-ray dose fluctuations, providing a hardware basis for the training pause function and forced training function.

[0041] At the same time, the data curves of tube current and tube voltage during the startup of the X-ray tube and the current and voltage data curves at the power supply end are calculated and drawn, and the training power supply curve is obtained according to the intersection area of ​​the curves. The power supply is implemented smoothly and continuously according to the curve, so that the power supply parameters at any time during the training process match the current optimal working power of the X-ray tube, thereby optimizing the rationality of the training process. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a module schematic diagram of the main circuit of the power generator of the present invention;

[0043] Figure 2 It is a schematic diagram of a voltage detection control circuit of a power generator of the present invention;

[0044] Figure 3 It is a schematic diagram of a current detection control loop of a power generator of the present invention;

[0045] Figure 4 It is a schematic diagram of the operating principle of a ray tube in the background technology;

[0046] Figure 5 It is a step-type power supply curve diagram of the existing training method in the background technology;

[0047] Figure 6 It is a power supply curve diagram of the training method of the present invention; DETAILED DESCRIPTION

[0048] The present invention is described in detail below with reference to the accompanying drawings.

[0049] A method for training a ray tube, using a power generator capable of linearly outputting a stable voltage as a power supply module for a training object, and the specific process is as follows:

[0050] Step 1, obtaining the last X-ray tube working date and time and the X-ray tube type;

[0051] Specifically, recording the last working date of the X-ray tube is the basic function of the X-ray tube control system. The X-ray tube type is the model of the X-ray tube installed on the current device. The X-ray tubes used on the market are generally standardized devices. The basic parameters of the X-ray tube can be obtained by looking up the table.

[0052] Step 2: confirm that the preheating time of the X-ray tube is t, and assume that the start time of the radiation preheating is T1 and the end time is T2, T2 = T1 + t;

[0053] Step 3: Confirm the basic parameters of the X-ray tube, including the maximum preheating tube voltage U max , Maximum preheating tube current I max , Maximum preheating power P max , Preheating starting tube voltage U s and preheating starting tube current I s ;

[0054] Step 4: Derivation of the final preheating power P of the X-ray tube over ;

[0055] P over =P MAX ·K p ;

[0056] In the formula, K p is the preheating power percentage, the theoretical value is between 0 and 100%. The power used by the power generator is calculated based on the radiation intensity required for this shooting task, K p = Power used / maximum power of power generator.

[0057] Step 5, draw a curve of the tube voltage of the X-ray tube changing with time;

[0058] Specifically, according to the formula:

[0059] U=U s ·log 10 (10P t +a);

[0060] Pt =t i / t;

[0061] Where, U is the preheating tube voltage, U s is the preheating starting tube voltage, P t is the ratio of preheating timing time to tube preheating time, a is a constant describing the leading amount of the preheating voltage rising trend (obtained by looking up the table), t i is the time interval between a single sampling cycle, T C The current time T of the X-ray tube preheating C =T1+t i ;

[0062] With a fixed sampling period, take multiple different T C Substituting numerical values ​​into the formula, we can obtain multiple discrete points that express the relationship between time and tube voltage. We use a smooth curve to connect the discrete points to form a curve of tube voltage changing with time.

[0063] Step 6: Draw a curve of the tube current of the X-ray tube changing with time;

[0064] Tube voltage U max As the dividing point, the X-ray tube current curve is divided into two parts;

[0065] When the tube voltage rises to U max Previously, it was obtained according to the following formula:

[0066] I=I s ;

[0067] When the tube voltage rises to U max Then, according to the following formula:

[0068] I=t i ·K+I s ;

[0069] K=P over / U over / t i ;

[0070] Where, I is the preheating tube current, I s is the preheating starting tube current, I s To preheat the starting tube current;

[0071] With a fixed sampling period, take multiple different t i Substituting numerical values ​​into the formula, we can obtain multiple discrete points that express the relationship between time and tube current. We connect the discrete points with a smooth curve to form a curve of tube current changing with time.

[0072] Step 7: Draw the tube power curve of the X-ray tube;

[0073] P=U·I

[0074] Where P is the preheating tube power, U is the preheating tube voltage, and I is the preheating tube power.

[0075] Step 8: Perform the X-ray tube training operation;

[0076] According to the above curve dynamics, the power supply parameters of the power generator are adjusted in real time until the training time reaches time T2, and the training is completed.

[0077] Reference Figure 6 The training curve is continuous and smooth, and the power supply data at any time point matches the current optimal working power of the X-ray tube.

[0078] Reference Figure 1-Figure 3 , a power generator, comprising a main circuit and a control circuit, the control circuit being used to control the main circuit;

[0079] The main circuit includes a rectifier unit, a filter unit, an inverter unit, a transformer unit and a voltage-doubling rectifier unit. The input circuit is sequentially connected to the rectifier unit, the filter unit, the inverter unit, the transformer unit and the voltage-doubling rectifier unit. The voltage-doubling rectifier unit is electrically connected to the ray tube via the output circuit.

[0080] The rectifier and filter unit adopts a bridge rectifier circuit and installs a filter capacitor in the loop. After the current is input into the rectifier and filter unit, it is first rectified and then filtered by the capacitor to obtain a smooth DC voltage.

[0081] The inverter unit can convert the DC voltage output by the rectifier and filter unit into a high-frequency square wave and output it to the next unit;

[0082] The transformer unit uses a high-voltage transformer, which consists of a primary coil and a secondary coil. The leakage inductance of the high-voltage transformer and the secondary current jointly resonate at the primary of the transformer, and the resonant frequency is synchronized with the inverter frequency, which reduces circuit loss and electromagnetic interference.

[0083] The voltage doubler rectifier unit is connected to the X-ray tube through a high-voltage cable. The current transmitted by the upper unit is amplified by the voltage doubler rectifier unit and then transmitted to the X-ray tube through the high-voltage cable.

[0084] The control loop is based on PID control theory and is used to control the main loop. The control loop has an independent timing unit built in, and the timing unit is directly associated with the main loop, and the duration of the forced training is preset;

[0085] The control circuit includes a voltage measurement and control unit and a current measurement and control unit. The specific control principle is as follows:

[0086] The differential equation for PID control is:

[0087]

[0088] Where:

[0089] y(t) is the output of the tube voltage;

[0090] n(t) is the given value of tube voltage;

[0091] e(t) is the control input, i.e. the deviation: e(t) = n(t) - y(t) the deviation between the controlled quantity and the given value;

[0092] u(t) is the output of control;

[0093] K p is the proportionality coefficient;

[0094] T i is the integration time constant;

[0095] T d is the differential time constant.

[0096] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, many changes can be made in the specific implementation methods and application scopes based on the ideas of the present invention. As long as these changes do not deviate from the concept of the present invention, they all belong to the protection scope of the present invention.

Claims

1. A method for training a X-ray tube, characterized in that: The specific process is as follows: Step 1, obtaining the last X-ray tube working date and time and the X-ray tube type; Step 2: confirm that the preheating time of the X-ray tube is t, and assume that the start time of the radiation preheating is T1 and the end time is T2, T2 = T1 + t; Step 3: Confirm the basic parameters of the X-ray tube; Step 4: derive the final preheating power of the X-ray tube; Step 5, draw a curve of the tube voltage of the X-ray tube changing with time; Step 6: Draw a curve of the tube current of the X-ray tube changing with time; Step 7: Draw the tube power curve of the X-ray tube; P=U·I Where P is the preheating tube power, U is the preheating tube voltage, and I is the preheating tube power; Step 8: Perform the X-ray tube training operation; According to the above curve dynamics, the power supply parameters of the power generator are adjusted in real time until the training time reaches time T2, and the training is completed.

2. A method for training a X-ray tube according to claim 1, characterized in that: In step 1, recording the last working date of the X-ray tube is the basic function of the X-ray tube control system. The X-ray tube type is the model of the X-ray tube installed on the current equipment. The X-ray tubes used on the market are generally standardized devices. The basic parameters of the X-ray tube can be obtained by looking up the table.

3. A method for training a X-ray tube according to claim 1, characterized in that: In step 3, the basic parameters specifically include the maximum preheating tube voltage U max , Maximum preheating tube current I max , Maximum preheating power P max , Preheating starting tube voltage U s and preheating starting tube current I s .

4. A method for training a X-ray tube according to claim 1, characterized in that: In step 4, the final preheating power of the X-ray tube is P over ; P over =P MAX ·K p ; In the formula, K p is the preheating power percentage, the theoretical value is between 0 and 100%. The power used by the power generator is calculated based on the radiation intensity required for this shooting task, K p = Power used / maximum power of power generator.

5. A method for training a X-ray tube according to claim 1, characterized in that: In step 5, according to the formula: U=U s ·log 10 (10P t +a); P t =t i / t; Where, U is the preheating tube voltage, U s is the preheating starting tube voltage, P t is the ratio of preheating timing time to tube preheating time, a is a constant describing the leading amount of the preheating voltage rising trend (obtained by looking up the table), t i is the time interval between a single sampling cycle, T C The current time T of the X-ray tube preheating C =T1+t i ; With a fixed sampling period, take multiple different T C Substituting numerical values ​​into the formula, we can obtain multiple discrete points that express the relationship between time and tube voltage. We use a smooth curve to connect the discrete points to form a curve of tube voltage changing with time.

6. A method for training a X-ray tube according to claim 1, characterized in that: In step 6, the tube voltage U max As the dividing point, the X-ray tube current curve is divided into two parts; When the tube voltage rises to U max Previously, it was obtained according to the following formula: I=I s ; When the tube voltage rises to U max Then, according to the following formula: I=t i ·K+I s ; K=P over / U over / t i ; Where, I is the preheating tube current, I s is the preheating starting tube current, I s To preheat the starting tube current; With a fixed sampling period, take multiple different t i Substituting numerical values ​​into the formula, we can obtain multiple discrete points that express the relationship between time and tube current. We connect the discrete points with a smooth curve to form a curve of tube current changing with time.

7. A power generator, characterized in that: It includes a main circuit and a control circuit, and the control circuit is used to control the main circuit; The main circuit includes a rectifier unit, a filter unit, an inverter unit, a transformer unit and a voltage-doubling rectifier unit. The input circuit is sequentially connected to the rectifier unit, the filter unit, the inverter unit, the transformer unit and the voltage-doubling rectifier unit. The voltage-doubling rectifier unit is electrically connected to the ray tube via the output circuit. The control loop operates based on PID control theory and is used to control the main loop.

8. A power generator according to claim 7, characterized in that: The control circuit has a built-in independent timing unit, which is directly linked to the main circuit and has a preset duration value for forced training.

Images