A control method of a point scanning power supply device and a point scanning power supply device

Abstract

The application relates to the technical field of point scanning, and provides a control method of a point scanning power supply device and the point scanning power supply device. The method determines a current segment control strategy according to the numerical relationship between current platforms. In the case that the numerical relationship between the current platforms is less than a first preset threshold, a second voltage unit supplies power, and a first voltage unit freewheels. In the case that the numerical relationship between the current platforms is not less than the first preset threshold, a time-sharing control strategy is determined according to the numerical relationship between a load current of a scanning magnet load and a target current. In the case that the numerical relationship between the load current and the target current is greater than a second preset threshold, the first voltage unit supplies power, and the second voltage unit freewheels. In the case that the numerical relationship between the load current and the target current is not greater than the second preset threshold, the second voltage unit supplies power, and the first voltage unit freewheels. The application takes into account the dynamic response speed and the current control precision, and is suitable for a heavy ion / proton accelerator point scanning treatment system.

Description

Technical Field

[0001] This invention relates to the field of point scanning technology, and in particular to a control method for a point scanning power supply device and a point scanning power supply device. Background Technology

[0002] Point scanning technology is a core technology in modern heavy ion / proton tumor therapy. It precisely guides the particle beam to different locations within the tumor target area by rapidly controlling changes in the current of the scanning magnet, achieving precision treatment. The dynamic response speed and current control accuracy of the point scanning magnet power supply directly determine the beam scanning positioning accuracy and treatment effect. With the miniaturization of heavy ion / proton therapy devices, the current and voltage of the scanning power supply are also increasing. In existing technologies, the single high-voltage H-bridge scheme requires high-voltage power supply to overcome the back electromotive force of the large inductance of the scanning magnet. However, high-voltage switching devices have high switching losses, limiting their operation to lower switching frequencies, resulting in large current ripple, low control accuracy, and limited dynamic response speed, making it difficult to meet the requirements of rapid current rise and high plateau accuracy. Summary of the Invention

[0003] This invention provides a control method and a point-scanning power supply device to address the shortcomings of existing point-scanning magnet power supplies in terms of response speed and control accuracy under large inductive loads. This invention balances dynamic response speed and current control accuracy, and is suitable for point-scanning therapy systems in heavy ion / proton accelerators.

[0004] This invention provides a control method for a point scanning power supply device, applied to a point scanning power supply device including a first voltage unit and a second voltage unit. A first terminal of a scanning magnet load is electrically connected to the output terminal of the first voltage unit, and a second terminal of the scanning magnet load is electrically connected to the output terminal of the second voltage unit. The supply voltage of the first voltage unit is greater than the supply voltage of the second voltage unit. The control method for the point scanning power supply device includes: determining a segmented current control strategy based on the numerical relationship between current plateaus; when the numerical relationship between the current plateaus is less than a first preset threshold, the segmented current control strategy supplies power to the second voltage unit, and the first voltage unit continues to supply power. When the numerical relationship between the current plateaus is not less than the first preset threshold, the current segment control strategy is to determine the time-sharing control strategy based on the numerical relationship between the load current of the scanning magnet load and the target current; when the numerical relationship between the load current of the scanning magnet load and the target current is greater than the second preset threshold, the time-sharing control strategy is to supply power to the first voltage unit, allow the second voltage unit to continue flowing, and the load current is in the current rising phase or the current falling phase; when the numerical relationship between the load current of the scanning magnet load and the target current is not greater than the second preset threshold, the time-sharing control strategy is to supply power to the second voltage unit, allow the first voltage unit to continue flowing, and the load current is in the current plateau phase.

[0005] According to a control method for a point scanning power supply device provided by the present invention, the numerical relationship between the current platforms is the absolute value of the difference between two adjacent current platforms, and the numerical relationship between the load current and the target current is the difference between the load current and the target current.

[0006] According to a control method for a point-scanning power supply device provided by the present invention, the first voltage unit includes a plurality of first voltage power modules connected in series. The first voltage power module includes a front-stage first voltage source, a first bus capacitor, and a rear-stage first H-bridge converter. The common terminal of the output positive terminal of the front-stage first voltage source and the first terminal of the first bus capacitor is electrically connected to the input positive terminal of the rear-stage first H-bridge converter. The common terminal of the output negative terminal of the front-stage first voltage source and the second terminal of the first bus capacitor is electrically connected to the input negative terminal of the rear-stage first H-bridge converter. The output terminal of the rear-stage first H-bridge converter serves as the output terminal of the first voltage unit.

[0007] According to a control method for a point-scanning power supply device provided by the present invention, the second voltage unit includes a plurality of parallel sub-power supply units, each sub-power supply unit including a plurality of second voltage power modules connected in series, the second voltage power module including a front-stage second voltage source, a second bus capacitor and a rear-stage second H-bridge converter, the common terminal of the output positive terminal of the front-stage second voltage source and the first terminal of the second bus capacitor being electrically connected to the input positive terminal of the rear-stage second H-bridge converter, the common terminal of the output negative terminal of the front-stage second voltage source and the second terminal of the second bus capacitor being electrically connected to the input negative terminal of the rear-stage second H-bridge converter, and the output terminal of the rear-stage second H-bridge converter serving as the output terminal of the second voltage unit.

[0008] According to a control method for a point scanning power supply device provided by the present invention, the power supply voltage of the first voltage unit is in the range of 200V~5000V, and the power supply voltage of the second voltage unit is in the range of 0V~200V.

[0009] According to a control method for a point-scanning power supply device provided by the present invention, the switching frequency range of the first H-bridge converter in the subsequent stage is 1kHz to 20kHz, and the switching frequency range of the second H-bridge converter in the subsequent stage is 20kHz to 100kHz.

[0010] According to the control method of a point scanning power supply device provided by the present invention, the method further includes: using a first proportional-integral regulator for current tracking when the load current is in the current rising phase or the current falling phase; and using a second proportional-integral regulator for current closed-loop control when the load current is in the current plateau phase.

[0011] According to the control method of a point scanning power supply device provided by the present invention, the method further includes: when the first voltage unit and the second voltage unit switch operating modes, determining the power supply duty cycle of the second voltage unit, and setting the second proportional-integral regulator according to the power supply duty cycle to perform a smooth transition of the current stage.

[0012] According to a control method for a point scanning power supply device provided by the present invention, the method further includes: determining the duty cycle of the second H-bridge converter after the second voltage unit based on the target current value, the supply voltage of the second voltage unit, and the resistance value of the scanning magnet load.

[0013] The present invention also provides a point scanning power supply device, including a first voltage unit and a second voltage unit, wherein a first end of the scanning magnet load is electrically connected to the output end of the first voltage unit, and a second end of the scanning magnet load is electrically connected to the output end of the second voltage unit, wherein the supply voltage of the first voltage unit is greater than the supply voltage of the second voltage unit; the point scanning power supply device adopts the control method of the point scanning power supply device described above.

[0014] The present invention provides a control method and a point scanning power supply device, which balances dynamic response speed and current control accuracy, and is suitable for point scanning therapy systems of heavy ion / proton accelerators.

[0015] The present invention has the following beneficial effects: (1) Extremely fast dynamic response: The high voltage series module provides a high total voltage and can achieve a current change rate of tens of thousands of A / s, which meets the requirements of point scanning and rapid beam positioning.

[0016] (2) Extremely high steady-state accuracy: The steady-state is controlled by a closed loop of low-voltage high-frequency module, with small ripple, high resolution, and current accuracy of ±5E-4 and below.

[0017] (3) The overall efficiency is significantly improved: the high-voltage unit only works when the current rises or falls and is turned off most of the time; the low-voltage unit has low voltage and low loss, resulting in high overall efficiency.

[0018] (4) Extremely scalable: By increasing or decreasing the number of series modules in the high-voltage unit and the number of low-voltage unit groups, it can flexibly adapt to scanning magnets with different inductance and current levels without redesigning the overall topology.

[0019] (5) Small current overshoot: The smooth adjustment algorithm is adopted so that the current overshoot is minimal when the power supply rises to the plateau. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a flowchart illustrating a control method for a point scanning power supply device provided by the present invention.

[0022] Figure 2 This is a schematic diagram of the structure of a point scanning power supply device provided by the present invention.

[0023] Figure 3This is one of the current waveforms and operating modes corresponding to a typical working process provided by the present invention.

[0024] Figure 4 This is the second diagram showing the correspondence between the current waveform and the operating mode of a typical working process provided by the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0026] Particle accelerator therapy devices are advanced medical equipment with advantages such as minimal damage to surrounding healthy tissue and significant killing effect on cancer cells. After being accelerated to a high-energy state by the accelerator, the particle beam is extracted and guided by a scanning magnetic field for precise irradiation according to the shape of the tumor. The main function of the point scanning power supply is to generate the excitation current required for the scanning magnetic field in real time. The treatment efficiency and effectiveness of particle accelerator therapy devices are highly dependent on the rate of change and accuracy of the scanning magnetic field.

[0027] As heavy ion / proton therapy devices become miniaturized, the current and voltage of the scanning power supply are also increasing, and the scanning power supply must also meet the following stringent requirements: Extremely high current change rate (di / dt): It is necessary to overcome the back electromotive force of a large inductor and achieve microsecond-level current plateau switching; Ultra-high steady-state current accuracy: Typically, the platform current accuracy is required to be better than ±5E-3; Low ripple and low overshoot: to avoid beam jitter or deviation from the target area, which could damage normal tissue; High efficiency and high reliability: meet the needs of continuous clinical work and avoid interruptions in treatment; Scalability: It can flexibly adapt to scanning magnets with different power levels and different inductance parameters.

[0028] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating a control method for a point scanning power supply device provided by the present invention.

[0029] Please refer to Figure 2 , Figure 2 This is a schematic diagram of a point scanning power supply device provided by the present invention.

[0030] This invention provides a control method for a point scanning power supply device, applied to a point scanning power supply device including a first voltage unit and a second voltage unit. A first terminal of a scanning magnet load is electrically connected to the output terminal of the first voltage unit, and a second terminal of the scanning magnet load is electrically connected to the output terminal of the second voltage unit. The supply voltage of the first voltage unit is greater than the supply voltage of the second voltage unit. The control method for the point scanning power supply device includes: 101: Determine the current segment control strategy based on the numerical relationship between current platforms; 102: When the numerical relationship between current platforms is less than the first preset threshold, the current segment control strategy supplies power to the second voltage unit and the first voltage unit continues to flow. 103: When the numerical relationship between current platforms is not less than the first preset threshold, the current segment control strategy is to determine the time-sharing control strategy based on the numerical relationship between the load current of the scanning magnet load and the target current. 104: When the numerical relationship between the load current of the scanning magnet load and the target current is greater than the second preset threshold, the time-sharing control strategy supplies power to the first voltage unit and freewheels the second voltage unit, and the load current is in the current rising stage or the current falling stage. 105: When the numerical relationship between the load current of the scanning magnet load and the target current is not greater than the second preset threshold, the time-sharing control strategy supplies power to the second voltage unit, the first voltage unit continues to flow, and the load current is in the current plateau stage.

[0031] In a preferred embodiment, the numerical relationship between current plateaus is the absolute value of the difference between two adjacent current plateaus, and the numerical relationship between the load current and the target current is the difference between the load current and the target current.

[0032] In a preferred embodiment, the first voltage unit includes multiple first voltage power modules connected in series. Each first voltage power module includes a front-end first voltage source, a first bus capacitor, and a rear-end first H-bridge converter. The common terminal of the front-end first voltage source, which is electrically connected to the first terminal of the first bus capacitor, is electrically connected to the positive input terminal of the rear-end first H-bridge converter. The common terminal of the front-end first voltage source, which is electrically connected to the second terminal of the first bus capacitor, is electrically connected to the negative input terminal of the rear-end first H-bridge converter. The output terminal of the rear-end first H-bridge converter serves as the output terminal of the first voltage unit.

[0033] In a preferred embodiment, the second voltage unit includes multiple parallel sub-power supply units. Each sub-power supply unit includes multiple second voltage power modules connected in series. Each second voltage power module includes a front-stage second voltage source, a second bus capacitor, and a rear-stage second H-bridge converter. The common terminal of the output positive terminal of the front-stage second voltage source and the first terminal of the second bus capacitor is electrically connected to the input positive terminal of the rear-stage second H-bridge converter. The common terminal of the output negative terminal of the front-stage second voltage source and the second terminal of the second bus capacitor is electrically connected to the input negative terminal of the rear-stage second H-bridge converter. The output terminal of the rear-stage second H-bridge converter serves as the output terminal of the second voltage unit.

[0034] To address the technical challenge of existing point-scanning magnet power supplies failing to simultaneously achieve high response speed, control accuracy, efficiency, and reliability under large inductive loads, this invention provides a point-scanning magnet power supply device with high and low voltage modular series connection and time-sharing and current segment coordinated control. This enables high-voltage rapid drive during the rise process, ensuring ultra-large di / dt; low-voltage fine adjustment of the current platform, ensuring ultra-high current accuracy; modular structure facilitates power expansion; and overall high efficiency, low overshoot, and low ripple.

[0035] The execution entity of the control method for the point scanning power supply device of the present invention is a control unit. The control unit can be set on the point scanning power supply device, which includes a first voltage unit and a second voltage unit. The current sampling unit and the scanning magnet load can also be set on the point scanning power supply device. The first voltage unit can be composed of m identical first voltage power modules (high voltage power modules) connected in series, where m≥1. The first voltage unit outputs a first DC voltage. The first voltage power module consists of a front-stage first voltage source (front-stage high voltage source), a first bus capacitor, and a rear-stage first H-bridge converter. The second voltage unit can be composed of one or two sets of identical sub-power supply units connected in parallel; each set of sub-power supply units consists of n identical second voltage power modules (low-voltage power modules) connected in series, where n≥1. The second voltage unit outputs a second DC voltage, which is less than the first DC voltage; the second voltage power module consists of a front-stage second voltage source (front-stage low-voltage source), a second bus capacitor, and a rear-stage second H-bridge converter; the output terminals of the first voltage unit and the second voltage unit are connected in series, and the two ends of the series connection are connected to a scanning magnet load; the control unit is connected to both the first and second voltage units respectively, and the control unit is configured as follows: In current segment control, when the absolute value of the difference between two given current plateaus is less than a first preset threshold, both the rising or falling current segment and the plateau segment are output by the low-voltage unit (second voltage unit), while the high-voltage unit (first voltage unit) provides freewheeling. When the absolute value of the difference between two given current plateaus is greater than the first preset threshold, time-sharing control is implemented.

[0036] Time-sharing control: When the difference between the load current and the target current is greater than the second preset threshold, the high-voltage unit is controlled to output a voltage of the corresponding polarity, and the low-voltage unit continues to flow, so as to realize rapid changes in the load current; when the difference between the load current and the target current is less than or equal to the second preset threshold, the high-voltage unit is controlled to be in the continuous flow state, and only the low-voltage unit group performs closed-loop regulation of the load current, while the high-voltage unit continues to flow, so as to realize high-precision steady-state control of the load current.

[0037] Furthermore, when the second voltage unit is a group of 1 sub-power supply units, the output current range is ±I0; when the second voltage unit is a group of 2 sub-power supply units, the output current range is ±2I0, thus doubling the current capacity.

[0038] Furthermore, when the two sets of sub-power supply units operate in parallel, the control unit adopts a master-slave current sharing or average current sharing strategy to control the output current deviation of the two sets of sub-power supply units to ≤±1%.

[0039] Furthermore, the first preset threshold is 3A, the second preset threshold is 0.5A, and the parameters of the first preset threshold and the second preset threshold are adjustable.

[0040] In a preferred embodiment, the power supply voltage of the first voltage unit is in the range of 200V to 5000V, and the power supply voltage of the second voltage unit is in the range of 0V to 200V.

[0041] In a preferred embodiment, the switching frequency of the first H-bridge converter in the subsequent stage ranges from 1kHz to 20kHz, and the switching frequency of the second H-bridge converter in the subsequent stage ranges from 20kHz to 100kHz.

[0042] As a preferred embodiment, the method further includes: using a first proportional-integral regulator for current tracking when the load current is in the current rising phase or the current falling phase; and using a second proportional-integral regulator for current closed-loop control when the load current is in the current plateau phase.

[0043] Furthermore, the control unit adopts a time-sharing composite control architecture with high-voltage feedback and low-voltage feedback; during the current rise or fall phase, the high-voltage unit H-bridge outputs the highest positive and negative voltages to achieve rapid current changes; during the current plateau phase, the low-voltage feedback uses a PI regulator to achieve closed-loop current control.

[0044] In a preferred embodiment, the method further includes: when the first voltage unit and the second voltage unit switch operating modes, determining the power supply duty cycle of the second voltage unit, and setting the second proportional-integral regulator according to the power supply duty cycle to achieve a smooth transition of the current stage.

[0045] As a preferred embodiment, the method further includes: determining the duty cycle of the second H-bridge converter following the second voltage unit based on the target current value, the supply voltage of the second voltage unit, and the resistance value of the scanning magnet load.

[0046] Furthermore, the control unit also employs a smooth transition algorithm, which adjusts the operating mode based on the current target current value when switching between the high-voltage and low-voltage unit groups. Second output voltage and the resistance value of the scanning magnet The required duty cycle of the low-voltage unit H-bridge converter during platform operation is calculated in advance. D And the integral value of the low-voltage PI regulator The value corresponding to this duty cycle is directly preset to ensure a smooth transition from the current rise segment to the current plateau segment.

[0047] ; .

[0048] The point scanning power supply device provided by the present invention is described below. The point scanning power supply device described below and the control method of the point scanning power supply device described above can be referred to in correspondence.

[0049] The present invention also provides a point scanning power supply device, including a first voltage unit and a second voltage unit, wherein a first end of a scanning magnet load is electrically connected to the output end of the first voltage unit, and a second end of the scanning magnet load is electrically connected to the output end of the second voltage unit, and the supply voltage of the first voltage unit is greater than the supply voltage of the second voltage unit; the point scanning power supply device adopts the control method of the point scanning power supply device described above.

[0050] In a preferred embodiment, the numerical relationship between current plateaus is the absolute value of the difference between two adjacent current plateaus, and the numerical relationship between the load current and the target current is the difference between the load current and the target current.

[0051] In a preferred embodiment, the first voltage unit includes multiple first voltage power modules connected in series. Each first voltage power module includes a front-end first voltage source, a first bus capacitor, and a rear-end first H-bridge converter. The common terminal of the front-end first voltage source, which is electrically connected to the first terminal of the first bus capacitor, is electrically connected to the positive input terminal of the rear-end first H-bridge converter. The common terminal of the front-end first voltage source, which is electrically connected to the second terminal of the first bus capacitor, is electrically connected to the negative input terminal of the rear-end first H-bridge converter. The output terminal of the rear-end first H-bridge converter serves as the output terminal of the first voltage unit.

[0052] In a preferred embodiment, the second voltage unit includes multiple parallel sub-power supply units. Each sub-power supply unit includes multiple second voltage power modules connected in series. Each second voltage power module includes a front-stage second voltage source, a second bus capacitor, and a rear-stage second H-bridge converter. The common terminal of the output positive terminal of the front-stage second voltage source and the first terminal of the second bus capacitor is electrically connected to the input positive terminal of the rear-stage second H-bridge converter. The common terminal of the output negative terminal of the front-stage second voltage source and the second terminal of the second bus capacitor is electrically connected to the input negative terminal of the rear-stage second H-bridge converter. The output terminal of the rear-stage second H-bridge converter serves as the output terminal of the second voltage unit.

[0053] In a preferred embodiment, the power supply voltage of the first voltage unit is in the range of 200V to 5000V, and the power supply voltage of the second voltage unit is in the range of 0V to 200V.

[0054] In a preferred embodiment, the switching frequency of the first H-bridge converter in the subsequent stage ranges from 1kHz to 20kHz, and the switching frequency of the second H-bridge converter in the subsequent stage ranges from 20kHz to 100kHz.

[0055] As a preferred embodiment, a first proportional-integral regulator is used for current tracking when the load current is in the rising or falling phase; and a second proportional-integral regulator is used for current closed-loop control when the load current is in the current plateau phase.

[0056] In a preferred embodiment, when the first voltage unit and the second voltage unit switch operating modes, the power supply duty cycle of the second voltage unit is determined, and the second proportional-integral regulator is set according to the power supply duty cycle to achieve a smooth transition of the current stage.

[0057] In a preferred embodiment, the duty cycle of the second H-bridge converter following the second voltage unit is determined based on the target current value, the supply voltage of the second voltage unit, and the resistance value of the scanning magnet load.

[0058] The point-scanning power supply device of the present invention includes a first voltage unit (high-voltage unit) and a second voltage unit (low-voltage unit), as well as a control unit, a current sampling unit, and a scanning magnet load. The first voltage unit is composed of four identical first voltage power modules (high-voltage power modules) connected in series. Each first voltage power module includes a three-phase rectifier circuit, a high-voltage DC bus capacitor, and a high-voltage full-bridge H-bridge inverter circuit. The DC bus voltage of a single module is 400V, and the total output voltage range of the first voltage unit is ±1600V. The second voltage unit is composed of two sets of identical sub-power supply units connected in parallel. Each set of sub-power supply units consists of four identical second voltage power modules (low-voltage power modules) connected in series. Each second voltage power module includes a three-phase rectifier circuit, a low-voltage DC bus capacitor, and a low-voltage full-bridge H-bridge inverter circuit. The DC bus voltage of a single module is 50V, and the total output voltage range of each set of sub-power supply units is ±200V. The output terminals of the two sets of sub-power supply units are connected in parallel, and the total output current range of the second voltage unit is ±2000A.

[0059] The output terminals of the first voltage unit and the second voltage unit are connected in series, and the two ends of the series connection are connected to a scanning magnet load. The scanning magnet load is equivalent to a series circuit of inductance L=4mH and resistance R=0.03Ω.

[0060] A current sampling unit is connected in series in the load circuit to collect the actual load current signal and transmit it to the control unit. The control unit outputs drive signals to the first voltage unit and the second voltage unit respectively to control the entire power supply device.

[0061] The control logic flow of this invention is as follows: Receive current command signal; Acquire the actual load current signal and calculate the current error; Current segment control determines whether the given current step current value is less than or equal to the first preset threshold 3A. If the given current step is less than or equal to 3A, the low-voltage unit is under closed-loop control during the current step and plateau phases, while the high-voltage unit continues to run current throughout the entire process. If the given current step is greater than 3A, the time-sharing control stage is entered. Determine if the time-sharing switching condition is met: current error > ±0.5A; If the condition of rapid current change is met, the high-voltage working mode is entered: the high-voltage unit outputs a voltage of the corresponding polarity, and the low-voltage unit group outputs 0V or freewheeling current. If the high voltage condition is not met, and the current error is less than ±0.5A, the system enters the low voltage operating mode: the high voltage unit is turned off, and it is placed in freewheeling mode; the low voltage unit group performs PI closed-loop regulation to stabilize the load current. Repeat the above steps until the system stops running.

[0062] The typical working process is as follows: Please refer to Figure 3 , Figure 3 This is one of the current waveforms and operating modes corresponding to a typical working process provided by the present invention.

[0063] Current segment control: The current jumps positively from 0A to 2A, and 2A is less than the first preset threshold of 3A. During the t0~t3 stage, the high-voltage unit is in freewheeling mode, and the low-voltage unit is in closed-loop control mode. The output current is stable at 2A during the t2~t3 stage.

[0064] Please refer to Figure 4 , Figure 4 The second diagram shows the current waveform and operating mode correspondence of a typical working process provided by this invention.

[0065] Current segment control: When the current jumps from 0A to 26A, and 26A is greater than the first preset threshold of 3A, time-sharing control is initiated. (1) Rapid current rise phase (t0~t1) The control unit detects a current error > ±0.5A and enters high-voltage mode; All four high-voltage power modules of the H-bridge inverter are working, with each module outputting +400V voltage, and the total output of the high-voltage unit is +1600V. The low-voltage unit group outputs 0V and is in freewheeling mode; The total output voltage overcomes the inductive back electromotive force of the scanning magnet, and the current rises rapidly at a rate of approximately 433333 A / s, reaching 26 A in about 60 μs.

[0066] (2) Pre-stabilization transition stage (t1~t2) When the current approaches the target value (error enters ±0.5A), the control unit first starts the low-voltage unit. Based on the target current of 26A and the scanning magnet resistance of 0.03Ω, it calculates that the output voltage required by the low-voltage unit in steady state is 0.78V, corresponding to an H-bridge duty cycle of 0.39%, and presets the integral value of the low-voltage power unit PI regulator. (3) Current steady-state maintenance stage (t2~t3) The high-voltage unit is completely shut off and is in freewheeling mode; The low-voltage unit uses PI closed-loop regulation at a switching frequency of 50kHz. The current stabilizes within the range of 26A ± 0.1A; Typical output ends.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for a point scanning power supply device, characterized in that, The power supply is applied to a dot scanning power supply device, which includes a first voltage unit and a second voltage unit. The first end of the scanning magnet load is electrically connected to the output end of the first voltage unit, and the second end of the scanning magnet load is electrically connected to the output end of the second voltage unit. The supply voltage of the first voltage unit is greater than the supply voltage of the second voltage unit. The control method for the point scanning power supply device includes: Based on the numerical relationship between current platforms, determine the current segment control strategy; When the numerical relationship between the current platforms is less than a first preset threshold, the current segment control strategy supplies power to the second voltage unit and the first voltage unit continues to flow. When the numerical relationship between the current platforms is not less than the first preset threshold, the current segment control strategy is to determine the time-sharing control strategy based on the numerical relationship between the load current of the scanning magnet load and the target current. When the numerical relationship between the load current of the scanning magnet load and the target current is greater than the second preset threshold, the time-sharing control strategy supplies power to the first voltage unit, the second voltage unit freewheels, and the load current is in the current rising stage or the current falling stage. When the numerical relationship between the load current of the scanning magnet load and the target current is not greater than the second preset threshold, the time-sharing control strategy supplies power to the second voltage unit, the first voltage unit continues to flow, and the load current is in the current plateau stage.

2. The control method for the point scanning power supply device according to claim 1, characterized in that, The numerical relationship between the current plateaus is the absolute value of the difference between two adjacent current plateaus, and the numerical relationship between the load current and the target current is the difference between the load current and the target current.

3. The control method for the point scanning power supply device according to claim 1, characterized in that, The first voltage unit includes multiple first voltage power modules connected in series. Each first voltage power module includes a front-end first voltage source, a first bus capacitor, and a rear-end first H-bridge converter. The common terminal of the front-end first voltage source, which is electrically connected to the first terminal of the first bus capacitor, is electrically connected to the positive input terminal of the rear-end first H-bridge converter. The common terminal of the front-end first voltage source, which is electrically connected to the second terminal of the first bus capacitor, is electrically connected to the negative input terminal of the rear-end first H-bridge converter. The output terminal of the rear-end first H-bridge converter serves as the output terminal of the first voltage unit.

4. The control method for the point scanning power supply device according to claim 3, characterized in that, The second voltage unit includes multiple parallel sub-power supply units. Each sub-power supply unit includes multiple second voltage power modules connected in series. Each second voltage power module includes a front-stage second voltage source, a second bus capacitor, and a rear-stage second H-bridge converter. The common terminal of the front-stage second voltage source, which is electrically connected to the first terminal of the second bus capacitor, is electrically connected to the positive input terminal of the rear-stage second H-bridge converter. The common terminal of the front-stage second voltage source, which is electrically connected to the second terminal of the second bus capacitor, is electrically connected to the negative input terminal of the rear-stage second H-bridge converter. The output terminal of the rear-stage second H-bridge converter serves as the output terminal of the second voltage unit.

5. The control method for the point scanning power supply device according to claim 1, characterized in that, The power supply voltage of the first voltage unit is in the range of 200V to 5000V, and the power supply voltage of the second voltage unit is in the range of 0V to 200V.

6. The control method for the point scanning power supply device according to claim 4, characterized in that, The switching frequency range of the first H-bridge converter in the subsequent stage is 1kHz to 20kHz, and the switching frequency range of the second H-bridge converter in the subsequent stage is 20kHz to 100kHz.

7. The control method for the point scanning power supply device according to any one of claims 1 to 6, characterized in that, Further includes: When the load current is in the rising or falling phase, the first proportional-integral regulator is used for current tracking. When the load current is at its current plateau, a second proportional-integral regulator is used for closed-loop current control.

8. The control method for the point scanning power supply device according to claim 7, characterized in that, Also includes: When the first voltage unit and the second voltage unit switch operating modes, the power supply duty cycle of the second voltage unit is determined, and the second proportional-integral regulator is set according to the power supply duty cycle to achieve a smooth transition of the current stage.

9. The control method for the point scanning power supply device according to claim 8, characterized in that, Further includes: The duty cycle of the second H-bridge converter following the second voltage unit is determined based on the target current value, the supply voltage of the second voltage unit, and the resistance value of the scanning magnet load.

10. A point scanning power supply device, characterized in that, The device includes a first voltage unit and a second voltage unit. A first end of the scanning magnet load is electrically connected to the output end of the first voltage unit, and a second end of the scanning magnet load is electrically connected to the output end of the second voltage unit. The supply voltage of the first voltage unit is greater than the supply voltage of the second voltage unit. The point scanning power supply device adopts the control method of the point scanning power supply device according to any one of claims 1 to 9.

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