X-ray machine startup control system and method

Abstract

The present invention belongs to the technical field of radiological diagnostic instruments, and relates to a startup control method for an X-ray machine. The startup control method first calculates the starting frequency of variable frequency startup, and adjusts the voltage to a minimum value; then performs open-loop frequency soft start; at the same time, detects the mA value of the X-ray machine cycle by cycle according to the operating frequency, and determines whether the mA value of the X-ray machine reaches a current startup threshold value; when the mA value of the X-ray machine is equal to or greater than the current startup threshold value, adjusts the voltage to a target set value, and starts closed-loop frequency adjustment to stabilize the mA value of the X-ray machine; finally, performs current soft start adjustment to the mA rated value of the X-ray machine, and realizes automatic soft start adjustment of the X-ray machine, which effectively reduces labor and time costs.

Description

Technical Field

[0001] The invention belongs to the technical field of radiological diagnostic instruments, and in particular relates to a start-up control system and method for an X-ray machine. Background Art

[0002] The X-ray machine adjustment process is to detect the mA value of the X-ray machine as feedback, and then perform PID calculation to output the frequency value to achieve the purpose of stabilizing the secondary current; in order to prevent the X-ray tube filament from being insufficiently preheated and affecting the safe operation of the X-ray machine, a reasonable startup method is required when starting the X-ray machine. The X-ray tube filament can be fully preheated during a slower startup process, but the effective working life of the X-ray tube is shortened, resulting in energy waste and low work efficiency; a too-fast startup method can easily cause damage to the X-ray machine and require a relatively high instantaneous power of the power supply, so the startup of the X-ray machine requires a method that matches performance and work efficiency. The previous X-ray machine startup method required adjusting different starting frequencies and starting speeds for each machine by observing the instrument parameters. Due to the differences in the X-ray tube filament characteristics, this method required setting the starting frequency and speed parameters for each machine. The parameter setting completely relied on technicians to check the instrument measurements and make repeated adjustments. The steps were cumbersome, required high personnel requirements, and were not conducive to industrial production. In addition, the previous adjustment method was only a single continuous closed-loop adjustment. Due to the hysteresis of the secondary current of the X-ray machine, it was easy to cause the closed-loop adjustment to produce integral saturation, resulting in the X-ray machine current overshoot fault protection. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a starting control system and method for an X-ray machine. The invention can effectively solve the technical problems that the soft-start parameters of the existing X-ray machine need to be repeatedly debugged and set by humans, the parameters are difficult to achieve automation and consistency, and the production efficiency is low; a single closed-loop adjustment cannot guarantee continuous soft-start before the current of the X-ray machine reaches the rated value, and it is very easy to cause overshoot of the filament current and false protection.

[0004] The present invention solves the technical problem by the following technical solutions:

[0005] A startup control system for an X-ray machine includes a voltage regulating circuit, a variable frequency drive circuit, and a control regulating circuit. The control regulating circuit is connected to the voltage regulating circuit and the variable frequency drive circuit respectively, and the control regulating circuit detects the mA current of the X-ray machine, controls the variable frequency drive circuit to adjust the operating frequency, and controls the voltage regulating circuit to adjust the working voltage.

[0006] A startup control method for an X-ray machine comprises the following steps:

[0007] Step S1 frequency soft start:

[0008] Calculate the starting frequency of variable frequency startup and adjust the voltage to the minimum value; increase the frequency cycle by cycle according to the operating frequency to perform frequency soft start. This stage is an open loop method;

[0009] Step S2 detects the mA value of the X-ray machine:

[0010] The mA value of the X-ray machine is detected cycle by cycle according to the operating frequency, and it is determined whether the mA value of the X-ray machine reaches the current starting threshold value; when the mA value of the X-ray machine is equal to or greater than the current starting threshold value, the voltage is adjusted to the rated value, and the frequency soft start ends;

[0011] Step S3 current soft start:

[0012] The initial target current value of the closed-loop regulation is set as the current starting threshold value. The closed-loop regulation frequency stabilizes the mA value of the X-ray machine, and the target current value is increased cycle by cycle according to the operating frequency. When the target current value is equal to the mA rated value of the X-ray machine, the current soft start ends.

[0013] Preferably, the current starting threshold value in step S2 is I f The calculation formula is:

[0014] I f =I s ×K1

[0015] Where Is is the mA rated value of the X-ray machine, and K1 is the proportionality coefficient, which ranges from 0.02 to 0.1.

[0016] Preferably, the current start threshold value is used as a characteristic critical point to determine the time point of closed-loop regulation and current soft start operation.

[0017] Preferably, the starting frequency f of the variable frequency start in step S1 is s The calculation formula is

[0018] f s =K2 / H

[0019] Where H is the high pulse width of the set rated frequency; K2 is the proportional coefficient, which takes a value of 0.1-0.2.

[0020] Preferably, in step S1, the open-loop frequency soft-start frequency output f n The calculation formula is

[0021] f n =f n-1 +f n-1 ×S

[0022] Where S is the rate coefficient, which ranges from 0.003 to 0.01.

[0023] Preferably, adjusting the voltage to a minimum value in step S1 means that the voltage should be kept at a minimum value during the open-loop frequency soft start process.

[0024] Preferably, during the current soft start process of step S3, the initial target current value of the closed-loop regulation is set as the current start threshold value, the closed-loop regulation frequency stabilizes the mA value of the X-ray machine, and the target current value is increased by calculating the following formula according to the operating frequency cycle by cycle;

[0025] I n =I n-1 +I n-1 ×0.02

[0026] In the formula, I n is the target current value of the nth cycle, I n-1 is the target current value of the n-1th cycle; when the target current value is equal to the mA rated value of the X-ray machine, the soft start ends.

[0027] The advantages and positive effects of the present invention are:

[0028] Compared with the existing X-ray machine startup control method, the present invention can better ensure continuous and smooth startup before the X-ray tube reaches the rated working state, reduce the current overshoot on the X-ray tube during startup, and reduce the impact on the input power load, simplify the production debugging steps, and only need to set a set of coefficients for the same type of machine, without the need to adjust the parameters of each X-ray machine, effectively reducing labor and time costs, and facilitating rapid industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is an electrical structure diagram of the start-up control system of the X-ray machine of the present invention.

[0030] Figure 2 It is a flow chart of the startup control method of the X-ray machine of the present invention.

[0031] Figure 3 It is a schematic diagram of frequency soft start in an example of the method of the present invention.

[0032] Figure 4 It is a schematic diagram of current soft starting in an example of the method of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and through specific embodiments. The following embodiments are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0034] Example:

[0035] like Figure 1As shown, the startup control system of the X-ray machine of the present invention includes a voltage regulating circuit, a variable frequency drive circuit, and a control regulating circuit. The control regulating circuit is connected to the voltage regulating circuit and the variable frequency drive circuit respectively, and the control regulating circuit detects the mA current of the X-ray machine, controls the variable frequency drive circuit to adjust the operating frequency, and controls the voltage regulating circuit to adjust the working voltage.

[0036] like Figure 2 As shown, the startup control method of the X-ray machine of the present invention comprises the following steps:

[0037] Step S1 frequency soft start:

[0038] Calculate the starting frequency of variable frequency starting according to the following formula:

[0039] f s =K2 / H

[0040] Where H is the high pulse width of the set rated frequency; K2 is the proportional coefficient, which takes a value of 0.1-0.2.

[0041] H is the inherent rated parameter of the X-ray machine. In this embodiment, the conventional parameters are taken as an example, H = 0.0012s, K2 = 0.15, and the calculated frequency conversion starting frequency f s =125Hz, such as Figure 3 The frequency at the start of medium frequency conversion T0-T1 should be 125Hz.

[0042] After calculating the starting frequency, adjust the voltage to the minimum value, such as Figure 3 The voltage V of the medium frequency waveform min The marked line starts to drive the frequency conversion circuit according to the calculated starting frequency, and the frequency is increased cycle by cycle according to the operating frequency for frequency soft start. This stage is an open loop mode. Open loop frequency soft start frequency output f n Calculated using the following formula:

[0043] f n =f n-1 +f n-1 ×S

[0044] Where S is the rate coefficient, which ranges from 0.001 to 0.005.

[0045] In this embodiment, S=0.002 is used for calculation. The frequency at the start of the frequency conversion T0-T1 is 125Hz, so f0=125Hz. If the frequency is increased period by period, Figure 3 The T1-T2 moment should correspond to f1=125.25Hz, Figure 3 Medium T2-T n The frequency calculation is similar.

[0046] Step S2 detects the mA value of the X-ray machine:

[0047] Keep the minimum voltage unchanged, gradually increase the frequency, the X-ray machine mA value will gradually increase, detect the X-ray machine mA value cycle by cycle, when it is detected that the X-ray machine mA value is equal to or greater than the current starting threshold value I f When Figure 3 Medium T n At this moment, the frequency soft start ends. f Calculated using the following formula:

[0048] I f =I s ×K1

[0049] Is is the mA rated value of the X-ray machine, K1 is the proportionality coefficient, and its value is 0.02-0.1.

[0050] Is is the inherent rated parameter of the X-ray machine. In this embodiment, the conventional parameters are taken as an example, Is = 5.0mA, K1 = 0.05, and the current starting threshold value I f =0.25mA, such as Figure 3 Medium T n I corresponding to the moment f The current start threshold should be 0.25mA.

[0051] It is detected that the mA value of the X-ray machine has reached the current start threshold, indicating that the X-ray machine filament has been preheated enough and can effectively emit electrons to generate current. The voltage begins to be adjusted to the target set value, such as Figure 4 The Vset line in the middle (because the voltage change in the actual circuit is not a sudden change, it takes a certain amount of time to change from the lowest voltage to the target set value, such as Figure 4 The variable frequency waveform voltage in the T0-Tx stage and the stable mA value are achieved through closed-loop frequency conversion. The speed of voltage change can be controlled in a balanced manner through closed-loop frequency conversion, so this embodiment does not consider the time change of voltage regulation).

[0052] Step S3 current soft start:

[0053] Start current soft start and set the initial target current value of closed-loop regulation to the current start threshold value I f , I has been calculated above f =0.25mA, then I n =0.25mA, such as Figure 4 The initial target current value corresponding to time T0.

[0054] Increase the target current value I cycle by cycle according to the operating frequency n , the specific method is calculated according to the following formula:

[0055] I n =I n-1 +In-1 ×0.02

[0056] The above calculation has been made f =0.25mA, Figure 4 T0 time I n =0.25mA, calculated according to the formula, Figure 4 The T1 moment should be I n =0.255mA, Figure 4 Medium T1-T n The target current value I n The calculation is similar.

[0057] As the target current value increases, the error between the target value and the actual mA value detected gradually increases. The closed-loop regulation uses this error to adjust the frequency change. The larger the error, the higher the frequency. Conversely, the smaller the error, the lower the frequency. When the detected mA value is equal to the current target value, the frequency reaches a balance and no longer changes. When the target current value increases to equal the mA rated value of the X-ray machine, Figure 4 T n At this moment, the soft start ends and the X-ray machine enters a stable working state.

[0058] Compared with the existing X-ray machine startup control system and method, the present invention can better ensure continuous and smooth startup before the X-ray tube reaches the rated working state, reduce the current overshoot on the X-ray tube during startup, and reduce the impact on the input power load, simplify the production debugging steps, and only need to set a set of coefficients for the same type number, without the need to adjust the parameters of each X-ray machine, effectively reducing labor and time costs, and facilitating rapid industrial production.

Claims

1. A startup control method for an X-ray machine, characterized in that: The following steps are involved: Step S1 frequency soft start: Calculate the starting frequency of variable frequency startup and adjust the voltage to the lowest value; increase the frequency cycle by cycle according to the operating frequency to perform frequency soft start. This stage is an open loop method; Step S2 detects the mA value of the X-ray machine: The mA value of the X-ray machine is detected cycle by cycle according to the operating frequency, and it is determined whether the mA value of the X-ray machine reaches the current starting threshold value; when the mA value of the X-ray machine is equal to or greater than the current starting threshold value, the voltage is adjusted to the rated value, and the frequency soft start ends; Step S3 current soft start: The initial target current value of the closed-loop regulation is set as the current starting threshold value. The frequency is adjusted through the closed loop to stabilize the mA value of the X-ray machine. The target current value is increased cycle by cycle according to the operating frequency. When the target current value is equal to the mA rated value of the X-ray machine, the current soft start ends.

2. The X-ray machine startup control method according to claim 1, characterized in that: The current starting threshold value I f The calculation formula is I f =I s ×K1 Where Is is the mA rated value of the X-ray machine, and K1 is the proportionality coefficient, which ranges from 0.02 to 0.

1.

3. The startup control method of an X-ray machine according to claim 2, characterized in that: The current start threshold value serves as a characteristic critical point and determines the timing of closed-loop regulation and current soft start operation.

4. The startup control method of an X-ray machine according to claim 2, characterized in that: The starting frequency f of variable frequency starting s The calculation formula is f s =K2 / H Where H is the high-level pulse width corresponding to the set rated frequency; K2 is the proportional coefficient, which takes a value of 0.1-0.

2.

5. The startup control method of an X-ray machine according to claim 2, characterized in that: The open-loop frequency soft-start frequency output f n The calculation formula is f n =f n-1 +f n-1 ×S In the formula, f n is the output frequency of the nth cycle, f n-1 is the output frequency of the n-1th cycle; S is the rate coefficient, which ranges from 0.003 to 0.

01.

6. The startup control method of an X-ray machine according to claim 2, characterized in that: The regulation voltage is the minimum value, which means that the voltage should be kept at the minimum value during the open-loop frequency soft start process.

7. The startup control method of an X-ray machine according to claim 2, characterized in that: During the current soft start process, the initial target current value of the closed-loop regulation is set as the current start threshold value, and the closed-loop frequency is adjusted to stabilize the mA value of the X-ray machine, and the target current value is increased cycle by cycle according to the operating frequency according to the following formula; I n =I n-1 +I n-1 ×0.02 In the formula, I n is the target current value of the nth cycle, I n-1 is the target current value of the n-1th cycle; When the target current value is equal to the mA rated value of the X-ray machine, the soft start ends.

8. A startup control system for an X-ray machine, characterized in that: The startup control method of the X-ray machine according to any one of claims 1 to 7 is adopted, and the system includes a voltage regulation circuit, a variable frequency drive circuit, and a control regulation circuit. The control regulation circuit is connected to the voltage regulation circuit and the variable frequency drive circuit respectively. The control regulation circuit detects the mA current of the X-ray machine, controls the variable frequency drive circuit to adjust the operating frequency, and controls the voltage regulation circuit to adjust the working voltage.

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