Active point scanning power supply and control method

Abstract

The application relates to an active point scanning power supply and a control method, which comprises the following steps: a low-voltage pre-stage voltage source module, a first pre-stage switching switch device, a second pre-stage switching switch device and a high-voltage pre-stage voltage source power supply module are connected in series to form a pre-stage voltage source; a rear-stage H-bridge module input end is connected between the first pre-stage switching switch device and the second pre-stage switching switch device, the first pre-stage switching switch device and the second pre-stage switching switch device change the pre-stage voltage source used by the rear-stage H-bridge module by changing the on and off states, and two output ends of the rear-stage H-bridge module are used for connecting an external load to output a preset current; a power supply controller is used for controlling the on and off states of the first pre-stage switching switch device, the second pre-stage switching switch device and the rear-stage H-bridge module to change the output current, and the closed-loop regulation of the output current is realized by using a pre-stage voltage feedback value and an output current feedback value.

Description

TECHNICAL FIELD

[0001] The application relates to a high-speed precision active point scanning power supply and a control method applied to high-performance irradiation, and relates to the field of particle accelerators. BACKGROUND

[0002] A particle accelerator generates charged ions by an ion source device, deflects an ion beam by a magnet device, and accelerates the ion beam by a high-frequency cavity, so as to finally obtain an ion beam or a charged single particle with a certain energy, which is used for research in the fields of high-energy physics, chemistry, materials, biomedicine, aerospace science, and the like. In the particle accelerator, heavy ion irradiation cancer treatment and microbeam irradiation device are two major application fields.

[0003] At present, a heavy ion treatment scheme mainly includes two categories: passive beam distribution and active beam distribution. In the passive beam distribution scheme, a heavy ion accelerator provides a fixed-energy beam for a terminal, a scanning magnet and a scatterer are used to longitudinally broaden an original Bragg peak, a range shifter on a path of the terminal is used to reduce the energy of the beam, so as to change the irradiation depth, and a collimator is used to intercept an irradiation field to achieve irradiation treatment in a predetermined range. In the active beam distribution scheme, the heavy ion accelerator changes the energy of a heavy ion beam according to the required irradiation depth, and adjusts the magnetic field strength of a pair of scanning dipole magnets of a beam terminal according to the required irradiation angle, so as to achieve accurate point-by-point irradiation treatment of the heavy ion on a cancer lesion of a patient. The magnetic field directions of the two scanning magnets are perpendicular to each other and perpendicular to the central axis of the track, one of the magnetic field directions is vertical, and the other of the magnetic field directions is horizontal.

[0004] During operation of the particle accelerator, a scanning power supply is connected with the scanning dipole magnet, and the output current of the scanning power supply induces a magnetic field with a corresponding size on the magnet after passing through the coil of the scanning magnet. The response speed and output precision of the scanning power supply greatly affect the magnetic field precision of the scanning magnet, and then affect the precision of the deflection angle of the ion beam, and finally affect the position precision of the beam or the single particle irradiated on the target material. In actual application, the output current waveform of the two scanning power supplies and the beam energy of the accelerator need to be preset according to the position and shape of the target material, the irradiation point sequence, the irradiation dose and the like. The irradiation experiment needs to achieve high precision in time and space. In the process of heavy ion irradiation cancer treatment, the irradiation area needs to be strictly controlled to reduce the irradiation dose of the normal tissue; in the single particle effect experiment, the irradiation precision affects the obtained sensitive position distribution information, and then affects the reinforcement strength of the device against the single particle effect, and then threatens the safe use of the microelectronic device for spaceflight. Therefore, the response speed and output precision of the active point scanning power supply need to reach a high standard to meet the needs of the above-mentioned accurate irradiation application.

[0005] At present, the traditional scanning power supply technology usually adopts a single front-end voltage source or a cascaded topology, and the control is usually adopted by a proportional integral derivative (PID) adjustment method. In high-performance irradiation occasions, the switching between different currents of the point scanning power supply and the platform time are required to be short enough to increase the irradiation point density and ultimately improve the performance of the ion beam irradiation. In such application occasions, the current response speed and control accuracy are required to be quite high. For example, in the scanning power supply of the first generation of domestic heavy ion therapy device, the adjacent current platform difference is 12A, the platform conversion time is about 200 microseconds, and the platform current duration is at least 100us. However, this index cannot meet the requirements of high-performance treatment. In the new generation of domestic heavy ion therapy device, the point scanning power supply requires that the adjacent current platform difference is 6A, the platform conversion time is at least 20us, and the platform current duration can reach 40us at least. The current response speed and output accuracy of the traditional scanning power supply need to be improved. SUMMARY

[0006] In view of the above problems, the purpose of the present application is to provide a high-speed precision active point scanning power supply and control method applied to high-performance irradiation, which can realize high-precision and fast-response current output and meet the high-irradiation precision requirements in the point scanning heavy ion therapy scheme and precise microbeam irradiation experiment.

[0007] To achieve the above purpose, the technical scheme provided by the present application is as follows:

[0008] In a first aspect, the present application provides an active point scanning power supply, comprising: a low-voltage front-end voltage source module, a high-voltage front-end voltage source module, a first front-end switching switch device, a second front-end switching switch device, a rear-end H-bridge module and a power supply controller.

[0009] The low-voltage front-end voltage source module, the first front-end switching switch device, the second front-end switching switch device and the high-voltage front-end voltage source supply module are connected in series to form a front-end voltage source.

[0010] The input end of the rear-end H-bridge module is connected between the first front-end switching switch device and the second front-end switching switch device, and the first front-end switching switch device and the second front-end switching switch device switch the front-end voltage source used by the rear-end H-bridge module by changing the on and off states.

[0011] The power supply controller is used to control the on and off states of the first front-end switching switch device, the second front-end switching switch device and the rear-end H-bridge module to change the output current, and to realize the closed-loop adjustment of the scanning power supply output current by using the front-end voltage feedback value and the output current feedback value.

[0012] Further, the low-voltage pre-stage voltage source module comprises a low-voltage pre-stage voltage source, a first pre-stage energy storage capacitor and a first voltage sensor; the low-voltage pre-stage voltage source is connected in parallel with the first pre-stage energy storage capacitor and the first voltage sensor, and is connected in series with the first pre-stage switching switch device;

[0013] The high-voltage pre-stage voltage source module comprises a high-voltage pre-stage voltage source, a second pre-stage energy storage capacitor and a second voltage sensor; the high-voltage pre-stage voltage source is connected in parallel with the second pre-stage energy storage capacitor and the second voltage sensor, and is connected in series with the second pre-stage switching switch device.

[0014] Further, the anode output end of the post-stage H-bridge module is provided with a DCCT for collecting the current amplitude output by the current voltage source.

[0015] Further, the post-stage H-bridge module comprises four switching devices S1-S4; only one of the switching device S1 and the switching device S2 of a vertical bridge arm of the post-stage H-bridge module is conductive; only one of the switching device S3 and the switching device S4 of another vertical bridge arm of the post-stage H-bridge module is conductive.

[0016] Further, only one of the first pre-stage switching switch device and the second pre-stage switching switch device is conductive;

[0017] When the first pre-stage switching switch device is conductive, the low-voltage pre-stage voltage source module is put into use;

[0018] When the second pre-stage switching switch device is conductive, the high-voltage pre-stage voltage source module is put into use;

[0019] When the switching device S1 and the switching device S4 are conductive, the scanning output voltage is equal to the input pre-stage voltage source, and the corresponding switching combination variable k=1;

[0020] When the switching device S2 and the switching device S3 are conductive, the scanning output voltage is equal to the negative input pre-stage voltage source, and the corresponding switching combination variable k=-1;

[0021] When the switching device S1 and the switching device S3 are conductive or the switching device S2 and the switching device S4 are conductive, the scanning output voltage is equal to zero.

[0022] Further, the power supply controller comprises a read-back interface, a control core, a driving interface and a communication interface;

[0023] The read-back interface is used for converting the digital signal converted from the analog signal fed back by the DCCT and the voltage sensor;

[0024] The control core is configured to acquire waveform and circuit parameter data through the communication interface, acquire a front-stage energy storage capacitor voltage value and an output current value through the read-back interface, calculate optimal switching combination variable k and duty cycle d required in a control period, and output a corresponding pulse width modulation waveform to the driving interface.

[0025] The driving interface is configured to control on-off states of switching devices of the front-stage switching device and the rear-stage H-bridge module, so as to make the scanning power supply output a current with a corresponding amplitude and realize closed-loop regulation of the scanning power supply output current.

[0026] Further, a plurality of active point scanning power supplies are connected in series or in parallel to meet the use requirements according to different load parameters, different output current rising rates and output power requirements.

[0027] In a second aspect, the present application further provides a control method of an active point scanning power supply, comprising:

[0028] The power supply controller controls the high-low voltage front-stage voltage source switching based on a scanning current given waveform judgment result.

[0029] The power supply controller detects the current power supply output current and the front-stage energy storage capacitor voltage in each control period in real time, and predicts the scanning power supply output current at the end of the current control period according to the optimal switching combination variable k and the optimal duty cycle variable d calculated in the last control period, so as to realize optimal control of the scanning power supply output current.

[0030] Further, the high-low voltage front-stage voltage source switching comprises:

[0031] The power supply controller calculates a current given waveform current variation rate, and judges whether the waveform is in a platform segment or a variation segment according to the current variation rate; if the given waveform is in the platform segment, the power supply controller switches the front stage to the low voltage front-stage voltage source; if the given waveform is in the variation segment, the power supply controller switches the front stage to the high voltage front-stage voltage source.

[0032] Further, the prediction of the scanning power supply output current at the end of the current control period to realize optimal control of the scanning power supply output current comprises:

[0033] The control core of the power supply controller acquires circuit parameters, a current given waveform and start time information through the communication interface.

[0034] The control core of the power supply controller starts to control the scanning power supply output current after the local timer reaches the preset start time.

[0035] In each control cycle, the control core of the power supply controller acquires the voltage of the front-stage energy storage capacitor and the amplitude of the output current through the read-back interface, and outputs corresponding pulse width modulation waveforms to the drive interface according to the k and d variables calculated in the last control cycle, and controls the switching devices of the active scanning power supply to act through the drive interface, so as to make the scanning power supply output a current with a corresponding amplitude.

[0036] The present application has the following characteristics due to the above technical solutions.

[0037] 1. The present application provides a front-stage switchable active point scanning power supply for providing excitation current for a scanning dipole magnet. The high-voltage front-stage voltage source enables the power supply to output current with a fast change rate, and the low-voltage front-stage voltage source enables the power supply to output current with high ripple precision. Therefore, the front-stage voltage sources are replaceable, adjustable and modular, and the active point scanning power supply can be used in series or in parallel, so as to meet different current change rate and current ripple precision requirements, and ensure that the ion beam or charged single particle can achieve high irradiation precision and density, thereby greatly improving the irradiation performance.

[0038] 2. The high-low voltage switching method provided by the present application enables the active point scanning power supply to use the high-voltage front-stage voltage source in the current change section and use the low-voltage front-stage voltage source in the current platform section, so that the output current has a large rising rate or falling rate in the change section, the irradiation point can be quickly switched, the time efficiency of irradiation experiment or irradiation treatment is improved, and the output current has a small ripple amplitude in the platform section, thereby improving the irradiation precision.

[0039] 3. The output prediction optimal control method provided by the present application ensures that the output current of the scanning power supply is accurately aligned with the given waveform at the starting moment of each control cycle.

[0040] In summary, the active point scanning power supply provided by the present application uses the high-low voltage switching method and the analytical model optimal control method to realize high-precision and fast-response current output, provides accurate excitation current for the scanning magnet of the active beam distribution scheme heavy ion cancer treatment accelerator terminal or precise microbeam irradiation terminal, and is suitable for scanning magnet excitation in heavy ion cancer treatment occasions and microbeam irradiation occasions under active and passive beam distribution modes, including single particle irradiation scanning magnet excitation. BRIEF DESCRIPTION OF DRAWINGS

[0041] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of preferred embodiments, and are not meant to limit the present application. Throughout the drawings, the same reference numerals are used for the same components. In the drawings:

[0042] Figure 1Active spot scanning power supply and scanning magnet load circuit model for the embodiment of the present application.

[0043] Figure 2 Active spot scanning power supply series-parallel connection schematic diagram for the embodiment of the present application.

[0044] Figure 3 Active spot scanning power supply output current waveform for the embodiment of the present application.

[0045] Figure 4 Power supply controller structure and its connection with external for the embodiment of the present application.

[0046] Figure 5 Output prediction optimal control flow chart for the embodiment of the present application. DETAILED DESCRIPTION

[0047] It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described, unless specifically identified as an order dependent step. It is also to be understood that additional or alternative steps can be employed.

[0048] Although the terms first, second, third, and the like can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can be only used to differentiate one element, component, region, layer or section from another region, layer or section. Terms such as "first", "second", and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0049] Spatially relative terms, such as "inner", "outer", "beneath", "below", "lower", "above", "upper", and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms can be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.

[0050] This invention provides an active point scanning power supply suitable for heavy ion irradiation therapy and precision microbeam irradiation, capable of providing high-speed response and precise excitation current to the diode scanning magnets of heavy ion accelerator terminals and precision microbeam terminals. This active point scanning power supply employs a high-low voltage dual-front-end circuit topology, giving it high current response speed and high output accuracy. The power supply utilizes a high-low voltage switching control strategy, satisfying both the high current rise rate requirement under dynamic output conditions and the current accuracy requirement under steady-state output conditions. Furthermore, the active point scanning power supply applies an output predictive optimal control method, ensuring that the output current is precisely equal to the given current at the end of each control cycle. The power supply can change the given current waveform according to the needs of heavy ion irradiation therapy or microbeam irradiation experiments. It allows for individual replacement of the low-voltage front-end module or the high-voltage front-end module, or the series-parallel connection of multiple active point scanning power supplies, depending on different current accuracy and current rise rate requirements. This invention significantly improves the irradiation quality in active and passive beam delivery schemes for cancer treatment and in precise microbeam irradiation experiments, including irradiation point accuracy, irradiation point density, and irradiation time efficiency.

[0051] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0052] Example 1: As Figure 1 As shown, the fast-response active point scanning power supply provided in this embodiment includes: a low-voltage front-end voltage source V1, a high-voltage front-end voltage source V2, and a first front-end energy storage capacitor C. Low Second pre-stage energy storage capacitor C High The system comprises: a first pre-stage switching device K1, a second pre-stage switching device K2, a rear-stage H-bridge module, a power controller, a DCCT (zero flux current sensor), a first voltage sensor M1, and a second voltage sensor M2, wherein:

[0053] Low-voltage front-end voltage source V1 and first front-end energy storage capacitor C Low The first voltage sensor M1 is connected in parallel to form a low-voltage front-end voltage source module, and the low-voltage front-end voltage source module is connected in series with the first front-end switching device K1.

[0054] High-voltage front-end voltage source V2 and second front-end energy storage capacitor C HighThe second voltage sensor M2 is connected in parallel with the high-voltage pre-stage voltage source module, and is connected in series with the second pre-stage switching switch device K2.

[0055] The low-voltage pre-stage voltage source module, the first pre-stage switching switch device K1, the second pre-stage switching switch device K2 and the high-voltage pre-stage voltage source module are connected in series to form a pre-stage voltage source.

[0056] The input end of the post-stage H-bridge module is connected with the pre-stage voltage source, that is, the input end of the post-stage H-bridge module is connected between the first pre-stage switching switch device K1 and the second pre-stage switching switch device K2, and the two pre-stage switching switch devices switch the pre-stage voltage source used by the post-stage H-bridge module by changing the on and off states. The two output ends of the post-stage H-bridge module are connected with the two ends of the external scanning magnet load, and the post-stage H-bridge module can output a preset current to the scanning magnet load by the chopper modulation method. The anode output end of the post-stage H-bridge module is provided with a DCCT for collecting the current amplitude of the current output by the current power supply.

[0057] The power supply controller is used to control the on and off states of the pre-stage switching switch device and the post-stage H-bridge module to change the output current, and realizes the closed-loop regulation of the output current by using the pre-stage voltage feedback value and the output current feedback value.

[0058] In a preferred embodiment, the scanning magnet load includes an inductance and a resistance, and the inductance L is connected in series with the resistance R.

[0059] In a preferred embodiment, the post-stage H-bridge module includes four switching devices S1-S4, and the switching devices can be transistor devices such as insulated gate bipolar transistors (IGBTs) and silicon carbide metal oxide semiconductor field effect transistors (SiC MOSFETs).

[0060] In a preferred embodiment, the low-voltage pre-stage voltage source V1 is a replaceable rectifier module, and the selected rectifier module needs to ensure that the output voltage range is relatively low compared with the high-voltage pre-stage voltage source, and the output voltage can be manually adjusted. The high-voltage pre-stage voltage source V2 is a replaceable rectifier module, and the selected rectifier module needs to ensure that the output voltage range is relatively high compared with the low-voltage pre-stage voltage source, and the output voltage can be manually adjusted.

[0061] In a preferred embodiment, as shown in FIG. 1, the power supply controller includes a control core, a read-back interface, a driving interface, a communication interface and a computing interface. Figure 4

[0062] The read-back interface converts the analog signals fed back by the DCCT and the voltage sensor into digital signals available for the power supply controller.

[0063] ​The control core obtains the voltage value of the front-stage energy storage capacitor and the output current value of the power supply through the read-back interface, controls the on-off state of the front-stage switching device and the rear-stage H-bridge switching device of the power supply through the driving interface, obtains the current given waveform data from the upper computer through the communication interface, calculates the optimal switching combination variable k and the duty cycle d required in the control period, outputs the corresponding pulse width modulation (PWM) waveform to the driving interface, and controls the switching device of the scanning power supply to act through the driving interface, so as to make the scanning power supply output the current with the corresponding amplitude, and realize the closed-loop regulation of the output current.

[0064] In a preferred embodiment, the active point scanning power supply can meet the requirements of various application occasions through series-parallel connection according to different scanning magnet load parameters, different output current rising rates and output power requirements, as shown in the circuit schematic diagram. Figure 2 The circuit schematic diagram shown contains n series branches, and each branch is composed of a plurality of parallelly connected active point scanning power supplies. All the modules in series-parallel connection collectively provide the excitation current for the scanning magnet load. The purpose of series connection is to improve the output voltage capability of the power supply, and the purpose of parallel connection is to improve the output power capability of the power supply.

[0065] In use, only one of the first front-stage switching device K1 and the second front-stage switching device K2 is turned on, the rear-stage H-bridge module includes the switching devices S1 to S4, and is the main circuit for controlling the output current amplitude. Only one of the switching devices S1 and S2 is turned on, and only one of the switching devices S3 and S4 is turned on. When the first front-stage switching device K1 is turned on, the low-voltage front-stage power supply V1 is put into use; when the second front-stage switching device K2 is turned on, the high-voltage front-stage power supply V2 is put into use. When the switching devices S1 and S4 are turned on, the output voltage of the scanning power supply is equal to the voltage of the input front-stage voltage source, corresponding to the switching combination variable k = 1; when the switching devices S2 and S3 are turned on, the output voltage of the scanning power supply is equal to the negative voltage of the input front-stage voltage source, corresponding to the switching combination variable k = -1; when the switching devices S1 and S3 are turned on or the switching devices S2 and S4 are turned on, the output voltage of the scanning power supply is equal to zero, which is the switching combination required by the power supply in the d·Ts to Ts period in the control period, d is the duty cycle variable, and T is the control period.

[0066] The active point scanning power supply of the embodiment provides the excitation current for the scanning magnet load, as shown in Figure 3As shown, the current is given as a waveform with step changes, and the waveform is divided into plateau segments and change segments. The current in the plateau segments remains constant, and the difference between the currents of two adjacent plateau segments is in the range of -6A to -1A and 1A to 6A. The change segment is the transition stage between two adjacent plateau segments, and the current change time is not more than the specified time. According to the requirements of the active beam distribution scheme, the scanning power supply needs to maintain the constant output current in the plateau segments, thereby maintaining the constant scanning magnet magnetic field and the fixed beam or single particle irradiation position. When the irradiation position needs to be changed, the scanning power supply needs to complete the output current amplitude change within the specified time. The output current change step is in the range of -6A to -1A and 1A to 6A, so if the specified time is 20 microseconds, the maximum current change rate is 300kA / s. The actual scanning power supply output waveform needs to be re-planned according to the information such as the irradiation point position, irradiation time, etc. required in heavy ion cancer treatment. The number of plateau segments in the actual waveform corresponds to the number of irradiation points, the plateau segment time corresponds to the irradiation time of each irradiation point, and the current change amplitude of each current change segment is determined by the difference between the positions of two adjacent irradiation points in the planning.

[0067] Embodiment 2: The embodiment also provides a control method of the active point drawing power supply, comprising:

[0068] Step S1: The power supply controller determines whether the current waveform output by the scanning power supply is in a plateau segment or a change segment, and controls the front-stage switching switch device to switch the front-stage voltage source, thereby realizing the switching of the high-voltage and low-voltage voltage sources.

[0069] Step S2: In each control cycle, the power supply controller calculates the optimal control variable of the next control cycle according to the circuit model parameters, the current front-stage voltage feedback value, the output current feedback value, and the current given waveform, the control variable including the switching combination variable k and the duty cycle variable d, thereby realizing the predictive optimal control of the scanning current output.

[0070] In a preferred embodiment, in the high-voltage and low-voltage voltage source front-stage switching control in step S1, the power supply controller calculates the current change rate of the current given waveform output by the scanning power supply, and determines whether the waveform is in a plateau segment or a change segment according to the current change rate. If the given waveform is in a plateau segment, the power supply controller switches the front stage to the low-voltage front-stage voltage source, and if the given waveform is in a change segment, the power supply controller switches the front stage to the high-voltage front-stage voltage source. The current change rate of the given waveform is the "derivative" of the waveform, and in actual calculation, the difference between two adjacent points is divided by the time difference between the two points. For example, if the point interval of the given waveform is 1us, the first given point is 0A, and the second given point is 0.01A, then the change rate at the first given point is equal to (0.01A-0A) / 1us=10000A / s. If the change rate is equal to 0A / s, it is considered that the given point is in a plateau segment, otherwise it is considered to be in a change segment.

[0071] In a preferred embodiment, the optimal control prediction in step S2 comprises the following steps:

[0072] Step S21: The power supply controller obtains the circuit parameters, current set waveform and start time from the host computer.

[0073] Step S22: The power supply controller controls the output current of the scanning power supply at the start time.

[0074] Step S23: In each control period, the power supply controller predicts the output current and calculates the optimal control variables for the next period, including the switching state combination variable of the switching device and the duty cycle variable.

[0075] Step S24: In each control period, the power supply controller controls the output current of the scanning power supply by using the optimal switching state combination and the optimal duty cycle calculated in the previous control period.

[0076] Further, in step S21, the host computer sets the power supply parameters and the circuit model parameters of the magnet load to the power supply controller, including the current set waveform, the control period Ts, the load inductance parameter L, the load resistance parameter R, and the front-end energy storage capacitor parameter C (C is equal to the first front-end energy storage capacitor value C low in the variation section, and is equal to the second front-end energy storage capacitor value C high ).

[0077] Further, in step S23, the power supply controller uses the optimal control variables k and d calculated in the previous control period to control the action of the four switching devices of the rear H-bridge module of the scanning power supply in each period, so that the scanning power supply outputs a high-precision predicted size of current. The power supply controller detects the current power supply output current and the front-end energy storage capacitor voltage in real time in each control period, and predicts the power supply output current and the front-end energy storage capacitor voltage at the end of the current control period according to the optimal control variables k and d calculated in the previous control period. The power supply controller calculates the optimal control variables for the next period, including the optimal switching combination variable k and the optimal duty cycle variable d, according to the current set value, the predicted power supply output current at the end of the current control period, and the front-end energy storage capacitor voltage.

[0078] The working process of the output prediction optimal control method in the high-precision control method of the fast-response scanning power supply will be described in detail through specific embodiments, including:

[0079] 1. The host computer plans the sequence of heavy ion beam irradiation points, the irradiation duration at each point, and the switching time between two points based on the three-dimensional shape of the cancer cell tissue in the patient undergoing irradiation treatment. Based on the heavy ion irradiation requirements and the circuit model parameters of the scanning power supply and scanning magnet, the host computer plans the beam energy of the accelerator, the given waveform of the active point scanning power supply current, and selects appropriate low-voltage and high-voltage pre-amplifier voltage sources (e.g., low-voltage pre-amplifier voltage source output range 5V to 30V, high-voltage pre-amplifier voltage source output range 100V to 500V).

[0080] 2. The host computer transmits the parameters C(C) of the pre-amplifier energy storage capacitor of the scanning power supply via the communication interface. High With C Low The inductance parameter L of the scanning magnet load, the resistance parameter R of the scanning magnet load, the current given waveform data, and the start-up time information are sent to the power controller control core.

[0081] 3. After the local timer reaches the preset start time, the control core begins to control the output current of the scanning power supply.

[0082] 4. During each control cycle, the first or second voltage sensor on the scanning power supply obtains the voltage of the activated pre-stage energy storage capacitor in real time, and the DCCT sensor obtains the output current amplitude in real time. The control core collects the readback values ​​of each sensor through the readback interface and saves the pre-stage energy storage capacitor voltage and output current in real time.

[0083] 5. In each control cycle, the control core calculates the optimal control variables k and d required for the next control cycle.

[0084] 6. In each control cycle, the control core outputs the corresponding pulse width modulation (PWM) waveform to the drive interface based on the k and d variables calculated in the previous control cycle, and controls the switching device of the scanning power supply through the drive interface, thereby causing the scanning power supply to output a current of the corresponding amplitude.

[0085] Furthermore, such as Figure 5 As shown, steps 4 to 6 are performed simultaneously. Taking the i-th and i+1-th control cycles as an example, for instance, the control cycle is 100 microseconds, and it is assumed that the current setpoint I at the end of the i+1-th control cycle is... 3i+1 * The current setpoint I at the end of the i-th control cycle is greater than 3i * (Equivalent to the current setpoint I at the start of the (i+2)th control cycle) 1i+2 * The current setpoint I at the start of the (i+1)th control cycle 1i+1 * The required switch combination variable k = 1, and the detailed process is as follows:

[0086] Step a: control core has completed the calculation of control parameters of the i-th control cycle in the i-1-th control cycle, including switch combination variable k i and duty cycle variable d i .

[0087] Step b: at the beginning of the i-th control cycle, the control core sets the switch combination and switch action time according to the optimal control variable k i and d i .

[0088] Since the switch combination variable k i = 1, switch devices S1 and S4 are in the on state, and S2 and S3 are in the off state during the 0 to d i · T S period; S1 and S3 are in the on state, and S2 and S3 are in the off state during the d i · T S to T S period. Each drive signal is output by the control core to the drive interface module, and then each switch device changes state according to the above sequence.

[0089] Step c: during the i-th control cycle, the control core collects the front-stage energy storage capacitor voltage and output current in real time through the voltage sensor, DCCT, and read-back interface.

[0090] Step d: during the i-th control cycle, the control core predicts the front-stage energy storage capacitor voltage and output current at the end of the i-th control cycle, i.e., the front-stage energy storage capacitor voltage and output current at the beginning of the i+1-th control cycle, according to the front-stage energy storage capacitor voltage and output current, k i , d i calculated in the i-th control cycle, and the preset C, L, and R.

[0091] Step e: during the i-th control cycle, the control core determines the switch combination variable k i+1 of the i+1-th control cycle according to the current given value change trend. If the current change rate is positive, k i+1 = 1, otherwise, k i+1 = -1.

[0092] Step f: during the i-th control cycle, the control core predicts and calculates the front-stage energy storage capacitor voltage and output current at the beginning of the i+1-th control cycle, and optimizes the d i+1 as the duty cycle parameter of the i+1-th control cycle according to the preset C, L, and R, switch combination variable k i+1 , and the optimal calculation of the current given value.

[0093] Step g: at the beginning of the i+1th control cycle, the control core determines the optimal control variable k i+1 and d i+1 The switch combination and switch action time in the control cycle are preset, and then the current output of the control cycle is completed.

[0094] Each of the embodiments in the specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the difference from other embodiments. In the description of the specification, the description of the terms "one embodiment", "some implementations" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the specification. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, a person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0095] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An active spot scanning power supply characterized by, The application relates to a high-voltage scanning power supply, which comprises the following parts: a low-voltage pre-stage voltage supply module, a high-voltage pre-stage voltage supply module, a first pre-stage switching switch device, a second pre-stage switching switch device, a post-stage H-bridge module and a power supply controller; the low-voltage pre-stage voltage supply module, the first pre-stage switching switch device, the second pre-stage switching switch device and the high-voltage pre-stage voltage supply supply module are connected in series to form a pre-stage voltage supply; The rear stage H bridge module input end is connected between the first front stage switching switch device and the second front stage switching switch device, the first front stage switching switch device and the second front stage switching switch device change the on, off state to switch the front stage voltage source used by the rear stage H bridge module;The rear stage H bridge module includes four switching devices S1-S4, the switching device S1 and the switching device S2 of a vertical bridge arm of the rear stage H bridge module have and only have one switching device on, the switching device S3 and the switching device S4 of the other vertical bridge arm of the rear stage H bridge module have and only have one switching device on;The first front stage switching switch device and the second front stage switching switch device have and only have one switching device on;When the first front stage switching switch device is on, the low-voltage front stage voltage source module is put into use;When the second front stage switching switch device is on, the high-voltage front stage voltage source module is put into use;When the switching device S1 and the switching device S4 are on, the scanning output voltage is equal to the input front stage voltage source, and the corresponding switching combination variable k= 1;When the switching device S2 and the switching device S3 are on, the scanning power output voltage is equal to the negative input front stage voltage source voltage, and the corresponding switching combination variable k= -1;When the switching device S1 and the switching device S3 are on or the switching device S2 and the switching device S4 are on, the scanning power output voltage is equal to zero. The power controller is used for controlling the conduction states of the first front-stage switching switch device, the second front-stage switching switch device and the rear-stage H-bridge module to change the output current, and realizes closed-loop regulation of the scanning power output current by using the front-stage voltage feedback value and the output current feedback value, specifically: the power controller detects the current scanning power output current and the front-stage energy storage capacitor voltage in real time in each control period, and predicts the scanning power output current at the end of the current control period according to the optimal switching combination variable and the optimal duty cycle variable obtained in the last control period k , so as to realize optimal control of the scanning power output current. d ​ 2. The active point scanning power supply of claim 1, wherein, the low-voltage pre-stage voltage supply module comprises a low-voltage pre-stage voltage supply, a first pre-stage energy storage capacitor and a first voltage sensor; the low-voltage pre-stage voltage supply is connected in parallel with the first pre-stage energy storage capacitor and the first voltage sensor and is connected in series with the first pre-stage switching switch device; the high-voltage pre-stage voltage supply module comprises a high-voltage pre-stage voltage supply, a second pre-stage energy storage capacitor and a second voltage sensor; the high-voltage pre-stage voltage supply is connected in parallel with the second pre-stage energy storage capacitor and the second voltage sensor and is connected in series with the second pre-stage switching switch device.

3. The active point scanning power supply of claim 2, wherein, A DCCT is arranged at an anode output end of the post-stage H-bridge module and is used for collecting the current amplitude output by the current voltage supply.

4. The active point scanning power supply of claim 3, wherein, The power supply controller comprises a back-reading interface, a control core, a driving interface and a communication interface; the back-reading interface is used for converting the digital signals of the analog signals fed back by the DCCT and the voltage sensor; The control core is used for acquiring waveform and circuit parameter data through the communication interface, acquiring front-stage energy storage capacitor voltage value and output current value through the read-back interface, and calculating optimal switching combination variable required by a control period k and duty cycle d , and outputting corresponding pulse width modulation waveform to a driving interface the driving interface is used for controlling the on-off state of the switching devices of the pre-stage switching switch device and the post-stage H-bridge module, so that the scanning power supply outputs the current with the corresponding amplitude and realizes the closed-loop regulation of the scanning power supply output current.

5. The active point scanning power supply of claim 1, wherein, According to different load parameters, different output current rising rates and different output power requirements, a plurality of active point scanning power supplies are connected in series and in parallel to meet the use requirements.

6. A method of controlling an active spot scanning power supply according to any one of claims 1 to 5, characterized by The power supply controller controls the switching of the high-voltage pre-stage voltage supply and the low-voltage pre-stage voltage supply based on the judgment result of the scanning current given waveform; controlling the switching of the high-voltage pre-stage voltage supply and the low-voltage pre-stage voltage supply comprises: The power supply controller detects the current power output current and the previous-stage energy storage capacitor voltage in real time in each control period, and changes the optimal switch combination variable calculated in the last control period k and the optimal duty cycle variable d to predict the scanning power output current at the end of the current control period, thereby achieving optimal control of the scanning power output current.

7. The control method according to claim 6, characterized by the power supply controller calculates the current given waveform current variation rate and judges whether the waveform is in a platform section or a variation section; if the given waveform is in the platform section, the power supply controller switches the pre-stage to the low-voltage pre-stage voltage supply; if the given waveform is in the variation section, the power supply controller switches the pre-stage to the high-voltage pre-stage voltage supply. The power supply controller predicts the scanning power supply output current at the end of the current control period and realizes the optimal control of the scanning power supply output current, which comprises:

8. The control method according to claim 6, characterized by, the control core of the power supply controller obtains the circuit parameters, the current given waveform and the starting time information through the communication interface; after the local timer of the control core of the power supply controller reaches the preset starting time, the control core starts to control the scanning power supply output current. ​ In each control cycle, the control core of the power supply controller acquires the voltage of the front-stage energy storage capacitor and the amplitude of the output current through the read-back interface, and according to the calculation of the variable in the last control cycle k 、 d the variable outputs a corresponding pulse width modulation waveform to the drive interface, and controls the switching device of the active scanning power supply to act through the drive interface, so as to make the scanning power supply output a current with a corresponding amplitude.

Images