CN115498890A - Method, device and storage medium for controlling a high voltage generator - Google Patents

Method, device and storage medium for controlling a high voltage generator Download PDF

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Publication number
CN115498890A
CN115498890A CN202211293311.2A CN202211293311A CN115498890A CN 115498890 A CN115498890 A CN 115498890A CN 202211293311 A CN202211293311 A CN 202211293311A CN 115498890 A CN115498890 A CN 115498890A
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voltage generator
signal
pulse width
width modulation
difference value
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吴昊
王丹
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Chenxin Electronics Suzhou Co ltd
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Chenxin Electronics Suzhou Co ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/3353—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The application relates to the field of DC-DC converters, which comprises a method for controlling a high-voltage generator, and the method comprises the steps of obtaining a first difference value between a real-time output voltage and a steady-state reference voltage at the output end of the high-voltage generator and a first phase-shifting angle between driving signals of a driving switch tube of the current high-voltage generator; in response to the first difference being greater than a first preset threshold and the first phase shift angle reaching a second preset threshold, adjusting a preset first switching frequency by using the first difference to obtain a second switching frequency; the pulse width modulation module uses the second switching frequency as input to obtain a third switching frequency which is output to a driving switching tube of the high-voltage generator; the third switching frequency is used to enable adjustment of the voltage gain of the high voltage generator. The switching method and the switching device have the advantages that the output voltage is prevented from being greatly vibrated and greatly overshot in the switching process, the rapidity of the switching process is improved, and the effect of greatly increasing the invalid dosage is avoided.

Description

Method, device and storage medium for controlling a high voltage generator
Technical Field
The present application relates to the field of DC-DC converters, and more particularly, to a method of controlling a high voltage generator, an apparatus for controlling a high voltage generator, and a computer storage medium.
Background
At present, in order to reduce the influence of the parasitic parameters of the transformer during high-voltage output, the topology of the medical X-ray high-voltage generator is an LCC resonant converter. Meanwhile, in order to adapt to different tissues and different diagnostic requirements, the output of the medical X-ray high-voltage generator usually has a wide variation range, the output voltage is usually dozens of kilovolts to hundreds of kilovolts, and the output current is usually dozens of milliamperes to hundreds of milliamperes. In order to meet the requirement of extremely wide range output, if the control scheme adopts a traditional Frequency conversion PFM (Pulse Frequency Modulation) mode, the operating Frequency range of the switching tube becomes extremely wide, which is not beneficial to the design of magnetic components and the processing of EMI. Therefore, the control scheme often adopts a control scheme combining frequency-conversion PFM and Phase Shift PSM (Phase Shift Modulation) control.
In addition, during the use process, the output load needs to be adjusted online, so that the switching between the PFM mode and the PSM mode may be problematic. In order to implement switching between PFM and PSM, a current control scheme first needs to determine a load demarcation point for switching between PFM and PSM, and needs to perform multiple experiments to establish demarcation point information of loads under different outputs. In addition, in order to cover a wide range of output, the bandwidth of a proportional integral controller (PI) is often designed to be very low, and if the control mode is directly switched from a PFM mode to a PSM mode in the load switching process, oscillation or overshoot of the output voltage may occur, and in addition, the problem of too long adjustment time also exists, so that the invalid dose in the diagnosis process is increased, and the health of a patient is affected.
Therefore, in order to meet the requirement of fast and smooth switching during on-line load switching so as to bring minimum influence to a patient, the invention provides a control mode for light load and heavy load switching, wherein the control mode is used for judging the output of a proportional integral controller (PI) controller, selecting different control loops and combining a feedforward control quantity to realize the aim of smooth and fast switching.
In view of the above-mentioned related art, the inventors found that at least the following problems exist in the related art: .
Disclosure of Invention
In order to meet the requirement of fast and smooth switching during on-line load switching so as to bring the minimum influence to a patient, the invention provides a control mode for light load and heavy load switching, which judges the output of a proportional integral controller (PI), selects different control loops and combines a feedforward control quantity to realize the aim of smooth and fast switching.
The application provides a method for controlling a high voltage generator, which adopts the following technical scheme:
in a first aspect, there is provided a method of controlling a high voltage generator, comprising,
acquiring a first difference value between a real-time output voltage of an output end of a high-voltage generator and a steady-state reference voltage, and a first phase-shifting angle between driving signals of a driving switch tube of the current high-voltage generator;
in response to the first difference being larger than a first preset threshold and the first phase shift angle reaching a second preset threshold, adjusting a preset first switching frequency signal by using the first difference to obtain a second switching frequency signal;
the pulse width modulation module uses the second switching frequency signal as input to obtain a first pulse width modulation signal output to a driving switching tube of the high-voltage generator; the first pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
In a second aspect, there is also provided a method of controlling a high voltage generator, comprising,
acquiring a first difference value between a real-time output voltage of an output end of a high-voltage generator and a steady-state reference voltage, and a first phase-shifting angle between driving signals of a driving switch tube of the current high-voltage generator;
in response to the first difference value being larger than a first preset threshold value and the first phase shift angle reaching a second preset threshold value, performing proportional integral on the first difference value to obtain a second difference value; adjusting a preset first switching frequency signal by using the second difference value to obtain a third switching frequency signal;
the pulse width modulation module uses the third switching frequency signal as input to obtain a second pulse width modulation signal output to a driving switching tube of the high-voltage generator; the second pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
In a third aspect, there is also provided a method of controlling a high voltage generator, comprising,
acquiring a first difference value between a real-time output voltage of an output end of a high-voltage generator and a steady-state reference voltage, and a first phase-shifting angle between driving signals of a driving switch tube of the current high-voltage generator;
in response to the first difference value being larger than a first preset threshold value and the first phase shift angle reaching a second preset threshold value, performing proportional integral on the first difference value to obtain a second difference value; adjusting and presetting a first switching frequency signal by using the second difference value to obtain a third switching frequency signal;
inputting the third switching frequency signal into a first amplitude limiter to obtain a fourth switching frequency signal with limited amplitude; the fourth switching frequency signal is used as the input of the pulse width modulation module to obtain a third pulse width modulation signal which is output to a driving switching tube of the high-voltage generator; the third pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
In a fourth aspect, there is also included a method of controlling a high voltage generator, comprising:
acquiring a first difference value between a real-time output voltage of an output end of the high-voltage generator and a steady-state reference voltage, and a fifth switching frequency of a driving signal of a driving switching tube of the current high-voltage generator;
in response to that the first difference value is larger than a first preset threshold value and the fifth switching frequency reaches a third preset threshold value, adjusting a preset second phase-shifting angle signal by using the first difference value to obtain a third phase-shifting angle signal;
the pulse width modulation module uses the third phase-shifting angle signal as input to obtain a fourth pulse width modulation signal output to a driving switch tube of the high-voltage generator; the fourth pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
In a fifth aspect, there is also provided a method of controlling a high voltage generator, comprising:
acquiring a first difference value between a real-time output voltage of an output end of the high-voltage generator and a steady-state reference voltage, and a fifth switching frequency of a driving signal of a driving switching tube of the current high-voltage generator;
in response to that the first difference value is larger than a first preset threshold value and the fifth switching frequency reaches a third preset threshold value, performing proportional integral on the first difference value to obtain a third difference value; adjusting a preset second phase-shifting angle signal by using the third difference to obtain a fourth phase-shifting angle signal;
the pulse width modulation module takes the fourth phase-shifting angle signal as input to obtain a fifth pulse width modulation signal which is output to a driving switch tube of the high-voltage generator; the fifth pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
In a sixth aspect, there is also provided a method of controlling a high voltage generator, comprising,
acquiring a first difference value between a real-time output voltage of an output end of the high-voltage generator and a steady-state reference voltage, and a fifth switching frequency of a driving signal of a driving switching tube of the current high-voltage generator;
in response to that the first difference value is larger than a first preset threshold value and the fifth switching frequency reaches a third preset threshold value, performing proportional integral on the first difference value to obtain a third difference value; adjusting a preset second phase-shifting angle signal by using the third difference value to obtain a fourth phase-shifting angle signal;
inputting the fourth phase-shift angle signal into a second amplitude limiter to obtain a fifth phase-shift angle signal with limited amplitude; the fifth phase-shift angle signal is used as the input of the pulse width modulation module to obtain a sixth pulse width modulation signal which is output to a driving switch tube of the high-voltage generator; the sixth pulse width modulation signal is used to implement the adjustment of the voltage gain of the high voltage generator.
In a seventh aspect, there is also provided an apparatus for controlling a high voltage generator, comprising:
the comparator is used for comparing the real-time output voltage of the output end of the high-voltage generator with the steady-state reference voltage to obtain a first difference value;
the superimposer is used for superimposing the first difference value on a preset first switching frequency signal or a preset second phase-shifting angle signal to respectively obtain a second switching frequency signal or a third phase-shifting angle signal;
the pulse width modulation module is used for obtaining a first pulse width modulation signal which is output to a driving switch tube of the high-voltage generator by using the second switching frequency signal as input; the first pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high-voltage generator;
or, the fourth pulse width modulation signal is used for obtaining a fourth pulse width modulation signal which is output to a driving switch tube of the high-voltage generator by using the third phase-shifting angle signal as input; the fourth pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
Preferably, the method further comprises the following steps:
the proportional integrator is used for performing proportional integration on the first difference value to obtain a second difference value; adjusting and presetting a first switching frequency signal by using the second difference value to obtain a third switching frequency signal;
or, the first difference value is subjected to proportional integral to obtain a third difference value; and adjusting a preset second phase-shifting angle signal by using the third difference to obtain a fourth phase-shifting angle signal.
Preferably, the method further comprises the following steps:
the amplitude limiter is used for inputting the third switching frequency into the amplitude limiter to obtain a fourth switching frequency signal with limited amplitude; the fourth switching frequency signal is used as the input of the pulse width modulation module to obtain a third pulse width modulation signal which is output to a driving switching tube of the high-voltage generator; the third pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high-voltage generator;
or, the fourth phase shift angle is input to an amplitude limiter, and a fifth phase shift angle signal with limited amplitude is obtained; the fifth phase-shifting angle signal is used as the input of the pulse width modulation module to obtain a sixth pulse width modulation signal which is output to a driving switch tube of the high-voltage generator; the sixth pulse width modulation signal is used to implement the adjustment of the voltage gain of the high voltage generator.
In an eighth aspect, a machine-readable storage medium is provided, which stores instructions that, when executed by a controller, can cause the controller to perform any one of the above-mentioned method aspects.
In summary, the present application includes at least one of the following beneficial technical effects:
1. PFM and PSM demarcation point information under different output voltages does not need to be determined through multiple experiments in the initial stage;
2. the large oscillation and large overshoot of the output voltage in the switching process are avoided;
3. the rapidity of the switching process is improved, and the invalid dosage is prevented from being greatly increased;
4. and the online smooth switching between frequency modulation control and phase shift control is realized.
Drawings
FIG. 1 is a schematic diagram of a prior art LCC resonant tank;
FIG. 2 is a schematic diagram of a first embodiment of a method of controlling a high voltage generator;
FIG. 3 is a schematic diagram of a second embodiment of a method of controlling a high voltage generator;
FIG. 4 is a schematic diagram of a third embodiment of a method of controlling a high voltage generator;
FIG. 5 is a schematic diagram of a fourth embodiment of a method of controlling a high voltage generator;
FIG. 6 is a schematic diagram of a fifth embodiment of a method of controlling a high voltage generator;
FIG. 7 is a schematic diagram of a sixth embodiment of a method of controlling a high voltage generator;
FIG. 8 is a block diagram of a first embodiment of an apparatus for controlling a high voltage generator;
FIG. 9 is a configuration diagram of a second embodiment of an apparatus for controlling a high voltage generator;
FIG. 10 is a configuration diagram of a third embodiment of an apparatus for controlling a high voltage generator;
FIG. 11 is a block diagram of the LCC resonant tank and an apparatus for controlling the high voltage generator;
FIG. 12 is a graph of the output voltage and current of an LCC resonator when switching from light load to heavy load in accordance with the present invention;
fig. 13 is a graph of the output voltage and current of the LCC resonator when switching from a heavy load to a light load in the present invention.
Description of reference numerals: 1. a comparator; 2. a superimposer; 3. a proportional integrator;
4. 5 an amplitude limiter; 6. and a pulse width modulation module.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is further described in detail below with reference to fig. 1-13 and the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
Interpretation of terms:
PFM: pulse Frequency Modulation; pulse frequency modulation is commonly applied to improve heavy load efficiency.
PSM: pulse Shift Modulation; the pulse phase shift modulation is generally used for controlling a high-voltage generator under light load, and the larger the phase shift angle is, the smaller the voltage gain is.
PWM: pulse Width Modulation; pulse width modulation.
PI: proportional Integral; proportional integral.
The application provides a method for controlling a high voltage generator, which adopts the following technical scheme:
the present application is essentially a control method for an LCC resonant converter. As shown in fig. 1, the LCC resonant converter includes 4 switching tubes, and an LCC resonant unit, and 1: n, of the transformer. LCC resonant converter for utilizing an input DC voltage V in Controlling on-off signals of the 4 switching tubes to realize inversion, and amplifying the alternating voltage obtained after inversion by a certain proportion; rectifying and filtering the amplified alternating voltage to obtain direct voltage V o Outputting; practical results, i.e. V in Amplification to V o (ii) a The high voltage generator for control is mainly a high voltage generator for medical X-rays. It is known that medical X-rays are rays used for checking images in a patient's body, and cannot be used for a long time, which may damage organs in the body if used for a long time. To accurately use medical X-rays for examining an organ of a patient, a high voltage generator generating X-rays needs to be accurately controlled. The disadvantages of the prior art, which have already been mentioned above, are not described in detail here. The technical scheme provided by the application is to provide a method for switching the high-voltage generators under different load conditions.
In a first aspect, as shown in fig. 2, there is provided a method of controlling a high voltage generator, comprising,
s101: acquiring a first difference value between a real-time output voltage of an output end of a high-voltage generator and a steady-state reference voltage, and a first phase-shifting angle between driving signals of a driving switch tube of the current high-voltage generator; in the application, the relation between the existing real-time output voltage and the real-time input voltage is actually established, and the relation is used for feeding back the change of the real-time output voltage to a device for controlling the input voltage so as to achieve the purpose of obtaining the real-time output voltage meeting the requirement; namely, a feedback mechanism is established to complete the steady state regulation of the real-time output voltage. Therefore, the real-time output voltage is firstly obtained and then is matched with the preset voltage V meeting the requirement ref And comparing to obtain a first difference value between the two values. In practical conditions, the first difference value fluctuates in a range, which reflects possible fluctuation and instability of real-time input voltage; or unstable real-time output voltage caused by different control signals of 4 switching tubes, unstable transformer and unstable resonator.
S102: in response to the first difference being larger than a first preset threshold and the first phase shift angle reaching a second preset threshold, adjusting a preset first switching frequency signal by using the first difference to obtain a second switching frequency signal; if the first difference value is continuously larger than a first preset threshold value, the real-time output voltage V is o With a preset voltage V ref The difference of (d) is not stable; when the first phase shift angle among the signals of the 4 switching tubes is controlled to be adjusted to a second preset threshold value, adjusting a first switching frequency signal by using the first difference value; the first switching frequency signal is preset, and it is desirable to control the frequency values of the signals of the 4 switching tubes. The second switching frequency signal is a frequency signal of the first switching frequency signal adjusted by a first difference value; the second switching frequency signal is used for modulation of a subsequent PWM module. The second preset threshold comprises 0 degrees. The first preset threshold value can be artificially set and is determined according to the requirement of the actual high-voltage generator, for example, 0.01V-1V. In generalPreset voltage V ref In the KV class.
S103: the pulse width modulation module (PWM module) uses the second switching frequency signal as input to obtain a first pulse width modulation signal output to a driving switching tube of the high-voltage generator; the first pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator. The PWM module outputs 4 values which are respectively used for controlling the on and off of 4 switching tubes so as to realize the direct current input voltage V by combining with the LCC resonance device in Inversion of (1).
Under the working mode of the embodiment, the phase-shifting angle is controlled, and the adjustment of the voltage gain is realized by changing the phase-shifting angle among the 4 switching tube driving signals. For example, if the first phase shift angle is larger, the actual output voltage V is larger o The smaller the gain; if the first phase shift angle is smaller, the actual output voltage V is o The greater the gain.
If V of the high voltage generator in Increase, resulting in V of actual output o The increase results in a larger first phase shift angle, which in turn results in a lower gain of the overall high voltage generator, resulting in a V of the actual output o And reducing and finishing steady state regulation.
If V of the high voltage generator in Decrease, resulting in V of the actual output o The decrease results in a smaller first phase shift angle, which increases the gain of the overall high voltage generator, resulting in a V of the actual output o And increasing to complete steady state regulation.
In a second aspect, as shown in fig. 3, there is also provided a method of controlling a high voltage generator, comprising:
s201: acquiring a first difference value between a real-time output voltage of an output end of a high-voltage generator and a steady-state reference voltage, and a first phase-shifting angle between driving signals of a driving switch tube of the current high-voltage generator;
s202: in response to the first difference value being larger than a first preset threshold value and the first phase shift angle reaching a second preset threshold value, performing proportional integral on the first difference value to obtain a second difference value; adjusting a preset first switching frequency signal by using the second difference value to obtain a third switching frequency signal;
s203: the pulse width modulation module uses the third switching frequency signal as input to obtain a second pulse width modulation signal output to a driving switching tube of the high-voltage generator; the second pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
Performing proportional integral on the first difference value to obtain a second difference value; and adjusting the preset first switching frequency signal by using the second difference value to obtain a third switching frequency signal. In the foregoing step, the first switching frequency signal is directly adjusted by the first difference, and the final V may be adjusted o Is caused to fluctuate so that V o Instability out of range and resulting in V in the switch from PSM to PFM o Is greater than the expected range. This is particularly undesirable for high voltage generators of medical X-rays. Therefore, the first difference value may be subjected to proportional integration to obtain a second difference value. The proportional integral is used here to accumulate errors and improve stability, and is used to adjust the preset first switching frequency signal. So that the first switching frequency signal is adjusted to the third switching frequency signal by the smoother second difference. Obtaining a second pulse width modulation signal output to a driving switch tube of the high-voltage generator by using the third switching frequency signal as input; the second pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
In a third aspect, as shown in fig. 4, there is also provided a method of controlling a high voltage generator, comprising:
s301: acquiring a first difference value between a real-time output voltage of an output end of a high-voltage generator and a steady-state reference voltage, and a first phase-shifting angle between driving signals of a driving switch tube of the current high-voltage generator;
s302: in response to the first difference value being larger than a first preset threshold value and the first phase shift angle reaching a second preset threshold value, performing proportional integral on the first difference value to obtain a second difference value; adjusting a preset first switching frequency signal by using the second difference value to obtain a third switching frequency signal;
s303: inputting the third switching frequency signal into a first amplitude limiter to obtain a fourth switching frequency signal with limited amplitude; the fourth switching frequency signal is used as the input of the pulse width modulation module to obtain a third pulse width modulation signal which is output to a driving switching tube of the high-voltage generator; the third pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
Inputting the third switching frequency into a first amplitude limiter to obtain a fourth switching frequency signal with limited amplitude; and the fourth switching frequency signal is used as the input of the pulse width modulation module to obtain a third pulse width modulation signal which is output to a driving switch tube of the high-voltage generator. Since the third switching frequency signal may have an amplitude greater than the expected value, a limiting amplitude is required when the third switching frequency signal is fed to the pulse width modulation module. After the first amplitude limiter is introduced, the obtained fourth switching frequency signal is input into a Pulse Width Modulation (PWM) module, and the third PWM signal is used to realize the adjustment of the voltage gain of the high voltage generator. The output fourth switching frequency is the frequency of the switch of the 4 switching tubes which finally controls the high-voltage generator.
To this end, a process of switching from PSM to PFM is achieved. I.e. the change of the method of controlling the high voltage generator which is implemented when the load of the high voltage generator needs to be switched from light load to heavy load.
Of course, if in response to the first difference being less than a first predetermined threshold, the first phase shift angle reaches a second predetermined threshold; i.e. the real-time output voltage V o And if the phase shift angle reaches the second preset threshold value, continuing the control mode of the PSM.
In a fourth aspect, as shown in fig. 5, there is also provided a method of controlling a high voltage generator, comprising:
s401: acquiring a first difference value between a real-time output voltage of an output end of the high-voltage generator and a steady-state reference voltage, and a fifth switching frequency of a driving signal of a driving switching tube of the current high-voltage generator; the first difference truly reflects whether the current real-time output voltage of the high-voltage generator is different from the expected steady-state reference voltage or not; reflecting the difference between the actual demand and the actual output. Since the PFM state is present, a fifth switching frequency of the driving signal needs to be obtained; at this time, the switching tube is driven by the fifth switching frequency to control the switching frequency of the switching tube. Because of the switching frequency, the output signals of the 4 switching tubes are different, so that the LCC resonant circuit starts to vibrate.
S402: in response to that the first difference value is larger than a first preset threshold value and the fifth switching frequency reaches a third preset threshold value, adjusting a preset second phase-shifting angle signal by using the first difference value to obtain a third phase-shifting angle signal; the first difference is larger than a first preset threshold value, which indicates that the actual output voltage of the high-voltage generator is still in an unstable state; the setting of the first preset threshold is flexible and depends mainly on the use of the high voltage generator itself. The stability of the output of the high-voltage generator is ensured by the smaller first preset threshold value; a larger first preset threshold value indicates that the output stability of the high voltage generator is less important. The first difference reflects the difference between the actual output voltage and the expected voltage, and the preset second phase-shift angle signal can be adjusted to obtain a third phase-shift angle signal by using the difference. The third phase-shifted angle signal is used for adjusting the phase shift of the input signal of the pulse width modulation module.
S403: the pulse width modulation module uses the third phase-shifting angle signal as input to obtain a fourth pulse width modulation signal output to a driving switch tube of the high-voltage generator; the fourth pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator. The third phase shift angle adjusts the phase shift angle among the driving signals of 4 switching tubes of the high-voltage generator;
under the working mode of PFM, the frequency conversion control realizes the adjustment of voltage gain by changing the frequency of 4 switching tube driving signals. For example, if the fifth switching frequency is smaller, the actual output voltage V is o The greater the gain; if the fifth switching frequency is higher, the actual output voltage V is o The smaller the gain.
If the pressure is highV of birth organ in Increase, resulting in V of actual output o The increase results in an increase in the fifth switching frequency, which in turn results in a decrease in the gain of the overall high voltage generator, resulting in a V of the actual output o And reducing and finishing steady state regulation.
If V of the high voltage generator in Decrease, resulting in V of actual output o The decrease results in a decrease of the fifth switching frequency, which in turn results in an increase of the gain of the overall high voltage generator, resulting in a V of the actual output o And increasing to complete steady state regulation.
In a fifth aspect, as shown in fig. 6, there is also provided a method of controlling a high voltage generator, comprising:
s501: acquiring a first difference value between a real-time output voltage of an output end of the high-voltage generator and a steady-state reference voltage, and a fifth switching frequency of a driving signal of a driving switching tube of the current high-voltage generator;
s502: in response to that the first difference value is larger than a first preset threshold value and the fifth switching frequency reaches a third preset threshold value, performing proportional integral on the first difference value to obtain a third difference value; adjusting a preset second phase-shifting angle signal by using the third difference to obtain a fourth phase-shifting angle signal;
s503: the pulse width modulation module takes the fourth phase-shifting angle signal as input to obtain a fifth pulse width modulation signal which is output to a driving switch tube of the high-voltage generator; the fifth pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
Performing proportional integral on the first difference value to obtain a third difference value; and adjusting a preset second phase-shifting angle by using the third difference to obtain a fourth phase-shifting angle. In the steady-state regulation, the first difference may be changed drastically, which results in the output V o It is easy to change drastically. Therefore, if proportional integral is added, the actual output voltage V can be smoothed o So that the output V of the whole high-voltage generator o The output can be gentle, large jitter can not appear, and especially for a medical X-ray high-voltage generator, in clinic, the side effect of a patient caused by severe X-ray change can be reduced. Ratio ofThe integration process is prior art and will not be described herein. Since the third difference is a relatively smooth change, the fourth phase-shifting angle obtained after controlling and adjusting the second phase-shifting angle is relatively smooth, and particularly, no large jitter occurs at the transition stage from PFM to PSM.
In a sixth aspect, as shown in fig. 7, there is also provided a method of controlling a high voltage generator, comprising:
s601: acquiring a first difference value between a real-time output voltage of an output end of the high-voltage generator and a steady-state reference voltage, and a fifth switching frequency of a driving signal of a driving switching tube of the current high-voltage generator;
s602: in response to that the first difference value is larger than a first preset threshold value and the fifth switching frequency reaches a third preset threshold value, performing proportional integral on the first difference value to obtain a third difference value; adjusting a preset second phase-shifting angle signal by using the third difference to obtain a fourth phase-shifting angle signal;
s603: inputting the fourth phase-shift angle signal into a second amplitude limiter to obtain a fifth phase-shift angle signal with limited amplitude; the fifth phase-shift angle signal is used as the input of the pulse width modulation module to obtain a sixth pulse width modulation signal which is output to a driving switch tube of the high-voltage generator; the sixth pulse width modulation signal is used to implement the adjustment of the voltage gain of the high voltage generator.
Inputting the fourth phase-shift angle signal into a second amplitude limiter to obtain a fifth phase-shift angle signal with limited amplitude; the fifth phase-shift angle signal is used as the input of the pulse width modulation module to obtain a sixth pulse width modulation signal which is output to a driving switch tube of the high-voltage generator; the sixth pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator. Because the amplitude of the fourth phase-shifting angle signal may exceed the expected value, a second amplitude limiter needs to be arranged to obtain a fifth phase-shifting angle signal with limited amplitude; in addition, the fifth phase-shift angle signal is used for adjusting the angle between the driving signals of 4 switching tubes of the high-voltage generator, thereby controlling the final actual voltage output V o And the control of the high-voltage generator is realized.
To this end, a process of switching from PFM to PSM is achieved. I.e. the change of the method of controlling the high voltage generator which is implemented when the load of the high voltage generator needs to be switched from a heavy load to a light load.
Of course, if it responds that the first difference is smaller than the first preset threshold and the fifth switching frequency reaches the third preset threshold, i.e. the actual output voltage V of the high voltage generator o And if the third switching frequency reaches a third preset threshold value, namely the maximum frequency value which can be reached by the fifth switching frequency, the PFM control mode is continued.
In a seventh aspect, as shown in fig. 8, there is also provided an apparatus for controlling a high voltage generator, comprising:
the comparator 1 is used for comparing the real-time output voltage of the output end of the high-voltage generator with the steady-state reference voltage to obtain a first difference value; in this embodiment, the comparator 1 may perform the addition with the real-time output voltage by an adder after inverting the steady-state reference voltage.
The superimposer 2 is used for superimposing the first difference value on a preset first switching frequency signal or a preset second phase-shifting angle signal to respectively obtain a second switching frequency signal or a third phase-shifting angle signal; in this embodiment, the superimposer 2 is an adder, and adds the first difference to the first switching frequency signal or the preset second phase-shifted angle signal to obtain the second switching frequency signal or the third phase-shifted angle signal, respectively.
The pulse width modulation module 6 is used for obtaining a first pulse width modulation signal which is output to a driving switch tube of the high-voltage generator by using the second switching frequency signal as input; the first pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high-voltage generator; and the pulse width modulation module (PWM) modulates the bias of a base electrode or a grid electrode of the MOS tube according to corresponding change to change the transistor or the conduction time, so that the output of the switching voltage-stabilized power supply is changed. This way the output voltage of the power supply can be kept constant as the operating conditions change. In the present embodiment, the pulse width modulation module 6 (PWM) is required regardless of whether it is in the light load state or the heavy load state.
Or, the fourth pulse width modulation signal is used for obtaining a fourth pulse width modulation signal which is output to a driving switch tube of the high-voltage generator by using the third phase-shifting angle signal as input; the fourth pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator. The third switching frequency signal or the fourth phase-shifted angle signal is an output of a Pulse Width Modulation (PWM) module. The respective functions are to adjust the driving signals of 4 switching tubes. The third switching frequency signal is used for adjusting the driving frequency of 4 switching tubes; and the fourth phase-shift angle signal is used for adjusting the phase-shift angle between the driving signals of the 4 switching tubes.
Preferably, as shown in fig. 9, the method further includes:
a proportional integrator 3, configured to perform proportional integration on the first difference value to obtain a second difference value; adjusting and presetting a first switching frequency signal by using the second difference value to obtain a third switching frequency signal;
or, the first difference value is subjected to proportional integral to obtain a third difference value; and adjusting a preset second phase-shifting angle signal by using the third difference to obtain a fourth phase-shifting angle signal. The function of the proportional integrator 3 is to smooth the first difference to obtain the second difference or the third difference. If the proportional integrator 3 is not provided, the second difference value is directly adopted for subsequent adjustment of the preset first switching frequency signal or the preset second phase-shifting angle signal, so that the real-time output voltage V of the high-voltage generator can still be ensured o Unevenness affects the output of the medical X-ray in this embodiment to fluctuate.
Preferably, as shown in fig. 10, the method further includes:
the amplitude limiters 4 and 5 are used for inputting the third switching frequency into the amplitude limiters to obtain a fourth switching frequency signal with limited amplitude; the fourth switching frequency signal is used as the input of the pulse width modulation module to obtain a third pulse width modulation signal which is output to a driving switching tube of the high-voltage generator; the third pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high-voltage generator;
or, the fourth phase-shifting angle is input to an amplitude limiter, and a fifth phase-shifting angle signal with limited amplitude is obtained; the fifth phase-shift angle signal is used as the input of the pulse width modulation module to obtain a sixth pulse width modulation signal which is output to a driving switch tube of the high-voltage generator; the sixth pulse width modulation signal is used to implement the adjustment of the voltage gain of the high voltage generator. The purpose of the limiters 4, 5 is to make the input of the pulse width modulation module (PWM) not too large, thereby affecting the use of the PWM.
As shown in fig. 11, is a complete diagram of the LCC resonant tank and the means to control the high voltage generator.
At V in Under the condition of input, the pulse width modulation module 6 (PWM) outputs and controls the switching frequency or the phase-shifting angle of 4 switching tubes; when the input voltage V in Increasing then the output voltage V o The increase results in an increase in the difference voltage output to the proportional integrator 3, and the output of the proportional integrator 3 also increases, resulting in an increase in the switching frequency or phase shift angle, so that the voltage output V of the LCC tank is increased o And reducing and finishing steady state regulation. If when the input voltage V is in Decrease, then output voltage V o The decrease results in a decrease of the difference voltage output to the proportional integrator 3, and the decrease of the output of the proportional integrator 3 results in a decrease of the switching frequency or the phase shift angle, so that the voltage output V of the LCC resonant tank is reduced o And increasing to finish steady state adjustment.
Fig. 12 is a graph showing the output voltage and current of the LCC resonator when switching from light load to heavy load in the present invention; also, the output voltage and current of the LCC resonator at the switching time from PSM to PFM are plotted. As is clear from the figure, both the voltage waveform and the current waveform are smooth. The voltage is in KV magnitude and the current is in mA magnitude. The switching time is short, and the change time period of the voltage waveform and the current waveform is short. The solid line represents a voltage waveform, and the dotted line represents a current waveform.
Fig. 13 is a graph showing the output voltage and current of the LCC resonator when switching from the heavy load to the light load in the present invention; also a plot of the output voltage, current of the LCC resonator at the time of switching from PFM to PSM. As is clear from the figure, both the voltage waveform and the current waveform are smooth. The voltage is in KV magnitude and the current is in mA magnitude. The switching time is short, and the change time period of the voltage waveform and the current waveform is short. The solid line represents a voltage waveform, and the dotted line represents a current waveform.
In an eighth aspect, there is also provided a machine-readable storage medium having stored thereon instructions which, when executed by a controller, are capable of causing the controller to perform the method of any of the above method claims.
In summary, the present application includes at least one of the following beneficial technical effects:
1. PFM and PSM demarcation point information under different output voltages does not need to be determined through multiple experiments in the initial stage;
2. the large oscillation and large overshoot of the output voltage in the switching process are avoided;
3. the rapidity of the switching process is improved, and the invalid dose is prevented from being greatly increased;
and the online smooth switching between frequency modulation control and phase shift control is realized.
Those skilled in the art will appreciate that all or part of the steps in the method for implementing the above embodiments may be implemented by a program, which is stored in a storage medium and includes several instructions to enable a single chip, a chip, or a processor (processor) to execute all or part of the steps in the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as disclosed in the embodiments of the present invention as long as it does not depart from the spirit of the embodiments of the present invention.
The foregoing is a preferred embodiment of the present application and is not intended to limit the scope of the present application in any way, and any features disclosed in this specification (including the abstract and drawings) may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.

Claims (10)

1. A method of controlling a high voltage generator, comprising: comprises the steps of (a) preparing a mixture of a plurality of raw materials,
acquiring a first difference value between a real-time output voltage of an output end of a high-voltage generator and a steady-state reference voltage and a first phase-shifting angle between driving signals of a driving switch tube of the current high-voltage generator;
in response to the first difference value being larger than a first preset threshold value and the first phase shift angle reaching a second preset threshold value, adjusting a preset first switching frequency signal by using the first difference value to obtain a second switching frequency signal;
the pulse width modulation module uses the second switching frequency signal as input to obtain a first pulse width modulation signal output to a driving switching tube of the high-voltage generator; the first pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
2. A method of controlling a high voltage generator, comprising: comprises the steps of (a) preparing a mixture of a plurality of raw materials,
acquiring a first difference value between a real-time output voltage of an output end of a high-voltage generator and a steady-state reference voltage and a first phase-shifting angle between driving signals of a driving switch tube of the current high-voltage generator;
in response to the first difference value being larger than a first preset threshold value and the first phase shift angle reaching a second preset threshold value, performing proportional integral on the first difference value to obtain a second difference value; adjusting a preset first switching frequency signal by using the second difference value to obtain a third switching frequency signal;
the pulse width modulation module uses the third switching frequency signal as input to obtain a second pulse width modulation signal output to a driving switching tube of the high-voltage generator; the second pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
3. A method of controlling a high voltage generator, comprising: comprises the steps of (a) preparing a substrate,
acquiring a first difference value between a real-time output voltage of an output end of a high-voltage generator and a steady-state reference voltage, and a first phase-shifting angle between driving signals of a driving switch tube of the current high-voltage generator;
in response to the first difference value being larger than a first preset threshold value and the first phase shift angle reaching a second preset threshold value, performing proportional integral on the first difference value to obtain a second difference value; adjusting and presetting a first switching frequency signal by using the second difference value to obtain a third switching frequency signal;
inputting the third switching frequency signal into a first amplitude limiter to obtain a fourth switching frequency signal with limited amplitude; the fourth switching frequency signal is used as the input of the pulse width modulation module to obtain a third pulse width modulation signal which is output to a driving switching tube of the high-voltage generator; the third pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
4. A method of controlling a high voltage generator, comprising:
acquiring a first difference value between a real-time output voltage of an output end of the high-voltage generator and a steady-state reference voltage, and a fifth switching frequency of a driving signal of a driving switching tube of the current high-voltage generator;
in response to that the first difference value is larger than a first preset threshold value and the fifth switching frequency reaches a third preset threshold value, adjusting a preset second phase-shifting angle signal by using the first difference value to obtain a third phase-shifting angle signal;
the pulse width modulation module uses the third phase-shifting angle signal as input to obtain a fourth pulse width modulation signal output to a driving switch tube of the high-voltage generator; the fourth pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
5. A method of controlling a high voltage generator, comprising:
acquiring a first difference value between a real-time output voltage of an output end of the high-voltage generator and a steady-state reference voltage, and a fifth switching frequency of a driving signal of a driving switching tube of the current high-voltage generator;
in response to that the first difference value is larger than a first preset threshold value and the fifth switching frequency reaches a third preset threshold value, performing proportional integral on the first difference value to obtain a third difference value; adjusting a preset second phase-shifting angle signal by using the third difference to obtain a fourth phase-shifting angle signal;
the pulse width modulation module uses the fourth phase-shift angle signal as input to obtain a fifth pulse width modulation signal output to a driving switch tube of the high-voltage generator; the fifth pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
6. A method of controlling a high voltage generator, comprising: comprises the steps of (a) preparing a substrate,
acquiring a first difference value between a real-time output voltage of an output end of the high-voltage generator and a steady-state reference voltage, and a fifth switching frequency of a driving signal of a driving switching tube of the current high-voltage generator;
in response to that the first difference value is larger than a first preset threshold value and the fifth switching frequency reaches a third preset threshold value, performing proportional integral on the first difference value to obtain a third difference value; adjusting a preset second phase-shifting angle signal by using the third difference to obtain a fourth phase-shifting angle signal;
inputting the fourth phase-shift angle signal into a second amplitude limiter to obtain a fifth phase-shift angle signal with limited amplitude; the fifth phase-shift angle signal is used as the input of the pulse width modulation module to obtain a sixth pulse width modulation signal which is output to a driving switch tube of the high-voltage generator; the sixth pulse width modulation signal is used to implement the adjustment of the voltage gain of the high voltage generator.
7. An apparatus for controlling a high voltage generator, comprising:
the comparator is used for comparing the real-time output voltage of the output end of the high-voltage generator with the steady-state reference voltage to obtain a first difference value;
the superimposer is used for superimposing the first difference value on a preset first switching frequency signal or a preset second phase-shifting angle signal to respectively obtain a second switching frequency signal or a third phase-shifting angle signal;
the pulse width modulation module is used for obtaining a first pulse width modulation signal which is output to a driving switch tube of the high-voltage generator by using the second switching frequency signal as input; the first pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high-voltage generator;
or, the fourth pulse width modulation signal is used for obtaining a fourth pulse width modulation signal which is output to a driving switch tube of the high-voltage generator by using the third phase-shifting angle signal as input; the fourth pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high voltage generator.
8. The apparatus of claim 7, further comprising:
the proportional integrator is used for performing proportional integration on the first difference value to obtain a second difference value; adjusting and presetting a first switching frequency signal by using the second difference value to obtain a third switching frequency signal;
or, the first difference value is subjected to proportional integral to obtain a third difference value; and adjusting a preset second phase-shifting angle signal by using the third difference to obtain a fourth phase-shifting angle signal.
9. The apparatus of claim 7, further comprising:
the amplitude limiter is used for inputting the third switching frequency into the amplitude limiter to obtain a fourth switching frequency signal with limited amplitude; the fourth switching frequency signal is used as the input of the pulse width modulation module to obtain a third pulse width modulation signal which is output to a driving switching tube of the high-voltage generator; the third pulse width modulation signal is used for realizing the adjustment of the voltage gain of the high-voltage generator;
or, the fourth phase-shifting angle is input to an amplitude limiter, and a fifth phase-shifting angle signal with limited amplitude is obtained; the fifth phase-shift angle signal is used as the input of the pulse width modulation module to obtain a sixth pulse width modulation signal which is output to a driving switch tube of the high-voltage generator; the sixth pulse width modulation signal is used to implement the adjustment of the voltage gain of the high voltage generator.
10. A machine-readable storage medium having stored thereon instructions, which when executed by a controller, are capable of causing the controller to perform the method of any one of claims 1-6.
CN202211293311.2A 2022-10-21 2022-10-21 Method, device and storage medium for controlling a high voltage generator Pending CN115498890A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211293311.2A CN115498890A (en) 2022-10-21 2022-10-21 Method, device and storage medium for controlling a high voltage generator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211293311.2A CN115498890A (en) 2022-10-21 2022-10-21 Method, device and storage medium for controlling a high voltage generator

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