Multi-level correction magnet power supply based on Buck circuit cascade

Abstract

This disclosure provides a multi-level calibrated magnet power supply based on cascaded Buck circuits, comprising: a power conversion unit including a switching power supply module, a Buck circuit module, and an H-bridge connected in sequence, for converting an external grid voltage into a DC voltage signal; a filter circuit unit connected to the power conversion unit, for filtering out high-frequency ripple in the DC voltage signal output by the power conversion unit before inputting it to the load; and a digital controller, one end of which is connected to the filter circuit unit for sampling the DC voltage signal, and the other end of which is connected to the power conversion unit for generating a PWM signal to drive the Buck circuit module, thereby adjusting the DC voltage signal in real time.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power supply, and in particular to a multi-level correction magnet power supply based on Buck circuit cascade. Background Art

[0002] In electron storage rings, the correction magnet power supply is an important component for real-time correction of beam position. It poses a challenge to researchers because it requires both fast response speed and high stability. H-bridge is widely used in correction magnet power supply because its power can flow in both directions and can quickly recover load power. To ensure its fast responsiveness, a higher voltage needs to be loaded on the DC side, which will increase the output ripple and affect the stability of the system; conversely, to ensure the stability of the system, it is necessary to increase the filter parameters, which affects the fast responsiveness of the power supply.

[0003] At present, the multi-level strategy is a good way to solve the response speed and stability. The cascaded H-bridge circuit is used to switch the working mode under different circuit states to take into account the system response speed and stability. However, this method greatly increases the complexity of the power supply through the cascade of multiple groups of H-bridge circuits, and the number of switching devices used is also greater. In addition, the use of wide bandgap devices to increase the switching frequency and reduce the filter parameters can also improve the system response speed and stability, but this method depends on the device characteristics.

[0004] Public Content

[0005] 1. Technical issues to be resolved

[0006] Based on the above problems, the present invention provides a multi-level correction magnet power supply based on Buck circuit cascade to alleviate the technical problems in the prior art that the complexity of the power supply is greatly increased by cascading multiple groups of H-bridge circuits, the number of switching devices used is also larger, and there is dependence on the characteristics of wide bandgap devices.

[0007] (II) Technical solution

[0008] The present disclosure provides a multi-level correction magnet power supply based on Buck circuit cascade, comprising:

[0009] A power conversion unit, including a switching power supply module, a Buck circuit module, and an H-bridge connected in sequence, for converting an external grid voltage into a DC voltage signal;

[0010] A filter circuit unit, connected to the power conversion unit, for filtering out high-frequency ripples in the DC voltage signal output by the power conversion unit and then inputting the signal into a load; and

[0011] A digital controller, one end of which is connected to the filter circuit unit for sampling the DC voltage signal, and the other end of which is connected to the power conversion unit for generating a PWM signal to drive the Buck circuit module, thereby adjusting the DC voltage signal in real time.

[0012] In the embodiment of the present disclosure, the switching power supply module includes N switching power supplies, where N≥2.

[0013] In the disclosed embodiment, the Buck circuit module includes N Buck circuits, which are connected in series and are independently connected to use the N switching power supplies.

[0014] In the disclosed embodiment, the outputs of the N Buck circuits connected in series are connected to the H bridge.

[0015] In the disclosed embodiment, the H-bridge includes a plurality of switching devices; the plurality of switching devices are used to switch the current direction according to load requirements and do not need to operate in a high-frequency switching state.

[0016] In the embodiment of the present disclosure, the digital controller includes an FPGA core control chip, a current sampling chip, and a current sensor.

[0017] In the disclosed embodiment, the N serially connected Buck circuits are modulated by means of carrier phase shifting.

[0018] In the disclosed embodiment, during modulation, the phases of the driving signals of the switching devices in the N Buck circuits are shifted by (360° / N)° respectively.

[0019] In an embodiment of the present disclosure, the switching device in the power conversion module is a silicon carbide MOSFET.

[0020] In the embodiment of the present disclosure, the sampling is closed-loop sampling.

[0021] (III) Beneficial effects

[0022] It can be seen from the above technical solution that the multi-level correction magnet power supply based on Buck circuit cascade disclosed in the present invention has at least one or part of the following beneficial effects:

[0023] (1) The multi-level purpose of the circuit is achieved by adding only a small number of switch tubes;

[0024] (2) Effectively balance the requirements of rapidity and stability of the correction magnet power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1It is a schematic diagram of the composition of a multi-level correction magnet power supply based on Buck circuit cascade according to an embodiment of the present disclosure;

[0026] Figure 2 1 is a schematic diagram of the circuit structure of a multi-level correction magnet power supply based on Buck circuit cascade according to an embodiment of the present disclosure;

[0027] Figure 3 It is a modulation principle diagram of carrier phase shifting of a multi-level correction magnet power supply based on Buck circuit cascade in an embodiment of the present disclosure;

[0028] Figure 4 is the output current step response waveform measured by the multi-level correction magnet power supply based on Buck circuit cascade in the embodiment of the present disclosure;

[0029] Figure 5 It is the measured output current step response waveform of ordinary H-bridge;

[0030] Figure 6 is the output current ripple measured by the multi-level correction magnet power supply based on Buck circuit cascade in the embodiment of the present disclosure;

[0031] Figure 7 It is the measured output current ripple of ordinary H-bridge. DETAILED DESCRIPTION

[0032] The present invention discloses a multi-level correction magnet power supply based on Buck circuit cascade. Aiming at the current situation that the fast response speed and low current ripple of the existing fast correction magnet power supply cannot be satisfied at the same time, a multi-level topology based on Buck circuit cascade is used to realize multi-level by using multiple Buck circuit cascades, which effectively takes into account the requirements of rapidity and stability of the correction magnet power supply.

[0033] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0034] In the embodiment of the present disclosure, a multi-level correction magnet power supply based on Buck circuit cascade is provided, combined with Figure 1 and Figure 2 As shown, the multi-level correction magnet power supply based on Buck circuit cascade includes:

[0035] A power conversion unit, including a switching power supply module, a Buck circuit module, and an H-bridge connected in sequence, for converting an external grid voltage into a DC voltage signal;

[0036] A filter circuit unit, connected to the power conversion unit, for filtering out high-frequency ripples in the DC voltage signal output by the power conversion unit and then inputting the signal into a load; and

[0037] A digital controller, one end of which is connected to the filter circuit unit for sampling the DC voltage signal, and the other end of which is connected to the power conversion unit for generating a PWM signal to drive the Buck circuit module, thereby adjusting the DC voltage signal in real time.

[0038] The switching power supply module includes three 12V switching power supplies;

[0039] The Buck circuit module includes three Buck circuits, which are connected in series and are independently connected to the three 12V switching power supplies.

[0040] It should be noted that the number of the above-mentioned switching power supply modules, the voltage values, and the number of Buck circuits are only used to illustrate this specific embodiment, and are not used to limit the present disclosure. Any adaptive adjustments made by any technical personnel in this field without departing from the technical ideas of the present disclosure shall not depart from the protection scope of the present disclosure.

[0041] The number of the H-bridge is set to 1, which includes 4 switch devices;

[0042] The outputs of the three Buck circuits connected in series are connected to the H-bridge. The four switch devices of the H-bridge do not need to work in a high-frequency switching state, and their function is to switch the output current direction according to load requirements.

[0043] All the switching devices in the power conversion module use silicon carbide MOSFET, which improves efficiency and reduces temperature rise while ensuring the switching frequency.

[0044] The DC voltage signal after LC filtering can be directly provided to the load.

[0045] The filter circuit unit is composed of a conventional LC filter;

[0046] The digital controller is used to control the sampling of output current and voltage, perform closed-loop PI operation of current, output PWM (Pulse width modulation) waves to drive switching devices in the Buck circuit, and realize local and / or remote control of the multi-level correction magnet power supply based on the Buck circuit cascade.

[0047] The digital controller includes a current sampling chip and a current sensor; the current sampling chip adopts AD7634; the current sensor adopts IT60S produced by LEM Company.

[0048] The digital controller is an indispensable part of the correction magnet power supply. The digital controller in the present disclosure uses FPGA as the core control chip.

[0049] In the embodiments of the present disclosure, Figure 3 As shown, in order to increase the equivalent switching frequency of the magnet power supply and improve the rapid response of the DC voltage signal, the multi-channel Buck circuit in the front stage adopts a carrier phase shifting method to form a modulation wave for modulation, and the phases of the switch tubes (switching devices) driving signals in the three Buck circuits are shifted by 120° respectively.

[0050] In the embodiments of the present disclosure, Figure 4 As shown, the correction magnet power supply is matched with a 1mH inductive load, the switching frequency is set to 100kHz, the filter inductor is 8μH, and the filter capacitor is 1.6μF. Figure 4 The output current and bridge output voltage waveforms under the step response from 0 to 5A, the current rise time is about 300μs. From the figure, we can see that during the current rise process, the bridge output voltage changes at different stages. At the beginning of the power rise, since the initial value of the PI regulator is 0, the duty cycle of the Buck circuit also starts from 0. At this time, the bridge output voltage is low and the output has only one level. When the output of the PI regulator increases, the duty cycle also increases. The bridge output voltage has a DC superimposed pulse voltage waveform. At this stage, the current rises rapidly; after the current reaches the target value, the circuit enters the steady state stage, and the output voltage pulse changes from the DC superimposed pulse state to the pulse output state again. In this process, the output voltage switches seamlessly between multiple levels, achieving a fast and stable output of the output current.

[0051] In this disclosure, Figure 5 This is the output current step response waveform of the H-bridge circuit, and the current rise time is about 1ms. Figure 5 The output voltage of the bridge circuit during the current rise process shown in the figure shows that since there is only one level, when the H-bridge reaches saturation output, the voltage is limited to the DC output voltage of the H-bridge and exits the saturation state after reaching steady state. Figure 4 , Figure 5 It can be seen that since the Buck circuit cascade topology has multiple levels, it can output different numbers of levels at different stages, and has a faster dynamic response than the traditional H-bridge topology.

[0052] Figure 6 and Figure 7 Comparison of the output current ripple between the Buck circuit cascade topology and the H-bridge, both using a 100 kHz switching frequency. Figure 6 The waveform shown is the equivalent output current ripple of 300kHZ when three Buck circuits are cascaded topology is applied. Figure 7 The output current ripple of the conventional H-bridge topology is shown as 100kHZ. Figure 6 and Figure 7By comparison, we can see that the H-bridge has a 100kHZ, 10mV fluctuation, while the output current ripple of the Buck circuit cascade topology is greatly reduced. Figure 7 The glitch in the waveform shown in is the measurement interference caused by the switch tube (switching device).

[0053] It can be seen from the above comparison that, compared with the traditional H-bridge circuit, the technical solution proposed in the present disclosure effectively takes into account the requirements of rapidity and stability of the correction magnet power supply.

[0054] The above is a detailed introduction to a multi-level correction magnet power supply and test method based on Buck circuit cascade provided in an embodiment of the present disclosure. This article uses specific examples to illustrate the principles and implementation methods of the present disclosure. The description of the above embodiments is only used to help understand the method of the present disclosure and its core idea; at the same time, for general technical personnel in this field, according to the ideas of the present disclosure, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present disclosure.

[0055] So far, the embodiments of the present disclosure have been described in detail in conjunction with the accompanying drawings. It should be noted that the implementation methods not shown or described in the drawings or the body of the specification are all forms known to ordinary technicians in the relevant technical field and are not described in detail. In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and ordinary technicians in the field can simply change or replace them.

[0056] According to the above description, those skilled in the art should have a clear understanding of the multi-level correction magnet power supply based on Buck circuit cascade disclosed in the present invention.

[0057] In summary, the present invention provides a multi-level correction magnet power supply based on Buck circuit cascade. In view of the current situation that the fast response speed and low current ripple of the existing fast correction magnet power supply cannot be satisfied at the same time, a multi-level topology based on Buck circuit cascade is used to realize multi-level by using multiple Buck circuit cascades, which effectively takes into account the requirements of speed and stability of the correction magnet power supply.

[0058] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure.

[0059] Moreover, the shapes and sizes of the components in the figures do not reflect the real size and proportion, but only illustrate the contents of the embodiments of the present disclosure. In addition, in the claims, any reference symbols between brackets shall not be constructed as limiting the claims.

[0060] Unless otherwise indicated, the numerical parameters in this specification and the appended claims are approximate values ​​and can vary according to the desired properties obtained through the content of the present disclosure. Specifically, all numbers used in the specification and claims to express the content of the composition, reaction conditions, etc., should be understood to be modified by the term "about" in all cases. In general, the meaning of the expression is to include a variation of ±10% in some embodiments, ±5% in some embodiments, ±1% in some embodiments, and ±0.5% in some embodiments by a specific number.

[0061] Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0062] The ordinal numbers used in the specification and claims, such as "first", "second", "third", etc., to modify the corresponding elements, do not themselves mean that the elements have any ordinal numbers, nor do they represent the order of one element and another element, or the order in the manufacturing method. The use of these ordinal numbers is only used to clearly distinguish a component with a certain name from another component with the same name.

[0063] In addition, unless the steps are specifically described or must occur in sequence, the order of the above steps is not limited to the above list, and can be changed or rearranged according to the required design. And the above embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, the technical features in different embodiments can be freely combined to form more embodiments.

[0064] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and set in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and in addition they may be divided into multiple submodules or subunits or subcomponents. All features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this manner may be combined in any combination, except that at least some of such features and / or processes or units are mutually exclusive. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose. Furthermore, in a unit claim that lists several devices, several of these devices may be embodied by the same hardware item.

[0065] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various disclosed aspects, in the above description of the exemplary embodiments of the present disclosure, the various features of the present disclosure are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the following intention: the claimed disclosure requires more features than the features explicitly recited in each claim. More specifically, as reflected in the claims below, the disclosed aspects are less than all the features of the single embodiment disclosed above. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, with each claim itself serving as a separate embodiment of the present disclosure.

[0066] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above description is only a specific embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A multi-level correction magnet power supply based on Buck circuit cascade, comprising: A power conversion unit, including a switching power supply module, a Buck circuit module, and an H-bridge connected in sequence, for converting an external grid voltage into a DC voltage signal; A filter circuit unit, connected to the power conversion unit, for filtering out high-frequency ripples in the DC voltage signal output by the power conversion unit and then inputting the signal into a load; as well as A digital controller, one end of which is connected to the filter circuit unit and is used to sample the DC voltage signal, and the other end of which is connected to the power conversion unit and is used to generate a PWM signal to drive the Buck circuit module, thereby adjusting the DC voltage signal in real time; The switching power supply module includes N switching power supplies, N≥2; the Buck circuit module includes N Buck circuits, the N Buck circuits are connected in series and are independently connected to the N switching power supplies; the N series-connected Buck circuits are modulated by carrier phase shifting; the phases of the driving signals of the switching devices in the N Buck circuits are shifted by 360° / N respectively; The H-bridge includes a plurality of switch devices; the plurality of switch devices are used to switch the current direction according to load requirements and do not need to operate in a high-frequency switching state.

2. According to the multi-level correction magnet power supply based on Buck circuit cascade in claim 1, the outputs of the N Buck circuits connected in series are connected to the H bridge.

3. According to the multi-level correction magnet power supply based on Buck circuit cascade in claim 1, the digital controller comprises an FPGA core control chip, a current sampling chip, and a current sensor.

4. According to the multi-level correction magnet power supply based on Buck circuit cascade according to claim 1, the switching device in the power conversion unit is a silicon carbide MOSFET.

5. According to the multi-level correction magnet power supply based on Buck circuit cascade as claimed in claim 1, the sampling is closed-loop sampling.

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