Fast correction magnet power supply based on GaN HEMT and correction method

Abstract

The invention provides a fast correction magnet power supply based on a GaN HEMT, and the power supply comprises an AC-DC conversion unit which is used for converting a power grid voltage into a DC input voltage; the power conversion unit is used for performing power conversion on the direct-current input voltage and outputting power to a magnet load; the DCCT is used for carrying out current sampling on the power output; the input and output voltage sampling unit is used for respectively sampling the input voltage and the output voltage of the power conversion unit; and the micro-control unit is used for outputting and adjusting a PWM (Pulse Width Modulation) control signal acting on the power conversion unit in real time according to the received correction instruction, the current sampling result and the voltage sampling result so as to realize stable output of the magnet power supply. The invention further provides a correction method based on the magnet power supply.

Description

Technical Field

[0001] The present disclosure relates to the technical field of magnet power supplies, and in particular to a low-latency GaN HEMT-based fast correction magnet power supply and a correction method for beam trajectory correction. Background Art

[0002] Existing light sources usually have magnetic field defects and installation errors of the magnets, setting errors of the excitation power supply, drift, ripple, changes in the foundation and vibration, etc., which cause the beam to deviate from the designed ideal orbit. The beam operating aperture of the strong focusing synchrotron accelerator is small, and there are extremely high requirements for the deviation of the beam orbit. Therefore, it is necessary to perform high-precision orbit measurement and correction of the beam running in the storage ring in real time. However, the current magnet power supply and correction methods can hardly meet the requirements. Summary of the invention

[0003] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, the present disclosure provides a fast correction magnet power supply and a correction method based on GaN HEMT.

[0004] In order to achieve the above purpose, the technical solution of the present invention is as follows:

[0005] According to an embodiment of one aspect of the present disclosure, a fast correction magnet power supply based on GaN HEMT is provided, comprising: an AC-DC conversion unit, a power conversion unit, a DCCT, an input\output voltage sampling unit, and a microcontroller unit. The AC-DC conversion unit is used to convert the grid voltage into a DC input voltage; the power conversion unit is used to perform power conversion on the DC input voltage to complete the power output to the magnet load; the DCCT (DC current sensor) is used to perform current sampling on the power output; the input\output voltage sampling unit is used to perform voltage sampling on the input and output voltages of the power conversion unit respectively; the microcontroller unit is used to output and adjust the PWM control signal acting on the power conversion unit in real time according to the received correction instruction, the current sampling result and the voltage sampling result, so as to achieve stable output of the magnet power supply.

[0006] According to an embodiment of the present disclosure, the power conversion unit is based on a topology structure of an H-type dual synchronous BUCK converter.

[0007] According to an embodiment of the present disclosure, a power conversion unit includes two half-bridge power stage modules based on GaN HEMT, namely a first half-bridge power stage module and a second half-bridge power stage module, wherein: the first half-bridge power stage module includes a first GaN HEMT (GaN HEMT-1) and a second GaN HEMT (GaN HEMT-2) arranged in parallel, respectively used to receive a first high-order PWM control signal H1 and a first low-order PWM control signal L1 issued by the power conversion unit; the second half-bridge power stage module includes a third GaN HEMT (GaN HEMT-3) and a fourth GaN HEMT (GaN HEMT-4) arranged in parallel, respectively used to receive a second high-order PWM control signal H2 and a second low-order PWM control signal L2 of the power conversion unit; the outputs of the first half-bridge power stage and the second half-bridge power stage are both connected to both ends of the magnetic load.

[0008] According to an embodiment of the present disclosure, the first high-order PWM control signal H1 and the second high-order PWM control signal H2 are two independent PWM signals directly generated by the microcontroller unit, and the first low-order PWM control signal L1 and the second low-order PWM control signal L2 are obtained by performing high-ground level complementary processing on the first high-order PWM control signal H1 and the second high-order PWM control signal H2, and inserting dead time.

[0009] According to the embodiment of the present disclosure, the combination of the first high-order PWM control signal H1 and the second low-order PWM control signal L2, or the second high-order PWM control signal H2 and the first low-order PWM control signal L1, will not be at high level at the same time, so no current output will be generated; when the duty cycle of the first high-order PWM control signal H1 is greater than the duty cycle of the second high-order PWM control signal H2, there will be a moment when the first high-order PWM control signal H1 and the second low-order PWM control signal L2 are at high level at the same time, thereby obtaining a positive current output; on the contrary, when the duty cycle of the first high-order PWM control signal H1 is less than the duty cycle of the second high-order PWM control signal H2, at certain moments the second high-order PWM control signal H2 and the first low-order PWM control signal L1 will be at high level at the same time, thereby generating a negative current output; for the situation where a larger current output is required, the duty cycles of the first high-order PWM control signal H1 and the second high-order PWM control signal H2 can be adjusted at the same time to enhance the current output and dynamic response performance.

[0010] According to the embodiment of the present disclosure, the microcontroller unit realizes closed-loop feedback by performing PID calculation, thereby adjusting the power output size or changing the output current direction in real time.

[0011] According to an embodiment of the present disclosure, the magnet power supply also includes an instruction receiving unit for receiving a current correction instruction issued by a host computer and transmitting it to a microcontroller unit, so that the microcontroller unit sends a PWM control signal to control the power conversion unit to output a target current value.

[0012] According to an embodiment of the present disclosure, the instruction receiving unit includes an optical fiber communication module and an Ethernet communication module.

[0013] According to an embodiment of the present disclosure, the magnet power supply further includes an ADC conversion module, which is used to convert current sampling and voltage sampling results into digital signals.

[0014] According to an embodiment of another aspect of the present disclosure, there is provided a correction method for a magnet power supply based on any one of the above items, comprising: performing voltage sampling on the input voltage and output voltage of the magnet power supply respectively; performing current sampling on the output of the magnet power supply; inputting a correction instruction including a target current value through a host computer; and adjusting a PWM control signal according to the voltage sampling result, the current sampling result, and the correction instruction until a target output result is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0016] Figure 1 A schematic diagram of a fast correction magnet power supply based on GaN HEMT according to an embodiment of the present disclosure is shown.

[0017] Figure 2 A schematic diagram of a power conversion unit according to an embodiment of the present disclosure is shown.

[0018] Figure 3 A schematic diagram of the timing sequence of PWM control signals of a fast correction magnet power supply based on GaN HEMT according to an embodiment of the present disclosure is shown.

[0019] Figure 4 A flow chart of a correction method for a fast correction magnet power supply based on GaN HEMT according to an embodiment of the present disclosure is shown.

[0020] Figure 5 The test waveform diagram of the GaN HEMT-based fast correction magnet power supply according to the embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0021] The present invention provides a fast correction magnet power supply and correction method based on GaN HEMT, introduces GaN HEMT devices in the power part of the magnet power supply for the first time, discloses a power supply topology composed of an H-type dual synchronous BUCK converter based on two GaN HEMT half-bridge power stages, two GaN chips form a dual synchronous BUCK circuit for power conversion, and its control logic is that two independent PWM signals are transformed into two pairs of complementary PWM signals through hardware complementation, which directly drive two GaN chips respectively, and realizes a bidirectional current output function by comparing the duty ratio of the independent PWM signals. The design realizes bidirectional current output, with a maximum output current of ±20A, a maximum output power of 600W, and a full load efficiency of 94%.

[0022] Compared with the third-generation light sources, the fourth-generation light sources currently under development use the design concept of diffraction limit cycles, which makes the electron beam stability at the light source point have a significant impact on the brightness, position, polarization and coherence of the light spot of the experimental station. Therefore, the fourth-generation light sources not only require higher control accuracy of orbit errors, but also need to control high-frequency orbit jitter, and put forward feedback bandwidth requirements of several kHz for the correction of the fast orbit feedback system.

[0023] As an important actuator of the fast orbit feedback system, the fast correction power supply can suppress the beam orbit disturbance within a certain bandwidth range, thereby ensuring the stability of the beam orbit near the extraction light source point. Compared with ordinary high-stability regulated current power supplies, it has higher requirements on the frequency response parameter of the system. The new fast correction power supply not only needs to meet the low drift and high precision (50ppm) of conventional magnet power supplies, but also needs to have extremely high dynamic response (higher than 5kHz) for magnet inductive loads.

[0024] The third generation of power semiconductor devices represented by gallium nitride high electron mobility transistors (GaN HEMT) have higher switching frequency and efficiency than traditional silicon-based devices. The high frequency characteristics of GaN HEMT can greatly improve the power density of the system. Secondly, at the same rated voltage, GaN HEMT has lower conduction losses, which can improve conversion efficiency while improving system reliability and service life. The use of GaN HEMT can reduce the overall system size and weight.

[0025] 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.

[0026] In an embodiment of the present disclosure, a fast correction magnet power supply based on GaN HEMT is provided, such as Figure 1As shown, the GaN HEMT-based fast correction magnet power supply includes: an AC-DC conversion unit, a power conversion unit, a DCCT, an input\output voltage sampling unit, and a microcontroller unit. The AC-DC conversion unit is used to convert the grid voltage into a DC input voltage; the power conversion unit is used to perform power conversion on the DC input voltage and complete the power output to the magnet load; the DCCT is used to perform current sampling on the power output; the input\output voltage sampling unit is used to perform voltage sampling on the input and output voltages of the power conversion unit respectively; the microcontroller unit is used to output and adjust the PWM control signal acting on the power conversion unit in real time according to the received correction instruction, the current sampling result and the voltage sampling result, so as to achieve stable output of the magnet power supply.

[0027] According to the embodiment of the present disclosure, Figure 1 , Figure 2 and Figure 3 As shown, the power conversion unit is based on the topology of the H-type dual synchronous BUCK converter, including two half-bridge power stage modules based on GaN HEMT, namely a first half-bridge power stage module and a second half-bridge power stage module, wherein: the first half-bridge power stage module includes a first GaN HEMT and a second GaN HEMT arranged in parallel, respectively used to receive a first high-order PWM control signal H1 and a first low-order PWM control signal L1 emitted by the power conversion unit, and the outputs of the first GaN HEMT and the second GaN HEMT are both connected to both ends of the load; the second half-bridge power stage module includes a third GaN HEMT and a fourth GaN HEMT arranged in parallel, respectively used to receive a second high-order PWM control signal H2 and a second low-order PWM control signal L2 of the power conversion unit, and the outputs of the third GaN HEMT and the fourth GaN HEMT are both connected to both ends of the load.

[0028] Combination Figure 2 and Figure 3 As shown, the first half-bridge power stage module and the second half-bridge power stage module are both equipped with a gate driver (GaN driver), with a nanosecond pulse width modulation (PWM) transmission delay, a minimum 3 nanosecond PWM dead time, and a maximum continuous current of 60A, which fully meets the design specification of the power supply of 20A. The two half-bridge power stage modules form a dual synchronous buck circuit for power conversion. Figure 3As shown, PWM H and PWM L signals control two half-bridge power stage modules respectively; PWM H includes a first high-order PWM control signal H1 and a second high-order PWM control signal H2, which are two independent PWM signals directly generated by the microcontroller unit, and PWM L signal includes a first low-order PWM control signal L1 and a second low-order PWM control signal L2, which are obtained by performing high-ground level complementary processing on the first high-order PWM control signal H1 and the second high-order PWM control signal H2, and inserting dead time.

[0029] According to the embodiment of the present disclosure, Figure 2 and Figure 3 As shown, when the duty cycle of the first high-order PWM control signal H1 and the second high-order PWM control signal H2 are the same, the combination of the first high-order PWM control signal H1 and the second low-order PWM control signal L2, or the second high-order PWM control signal H2 and the first low-order PWM control signal L1 will not be at high level at the same time, so no current output will be generated; when the duty cycle of the first high-order PWM control signal H1 is greater than the duty cycle of the second high-order PWM control signal H2, there will be a moment when the first high-order PWM control signal H1 and the second low-order PWM control signal L2 are at high level at the same time, thereby obtaining a positive current output; on the contrary, when the duty cycle of the first high-order PWM control signal H1 is less than the duty cycle of the second high-order PWM control signal H2, at certain moments, the second high-order PWM control signal H2 and the first low-order PWM control signal L1 will be at high level at the same time, thereby generating a negative current output; for the case where a larger current output is required, the duty cycles of the first high-order PWM control signal H1 and the second high-order PWM control signal H2 can be adjusted at the same time to enhance the current output and dynamic response performance. Compared with the metal oxide semiconductor field effect transistor (MOSFET) used in the previous switching power supply, those MOSFETs require complex peripheral driving circuits, while the GaN HEMT-based fast correction magnet power supply disclosed in the present invention allows direct TTL level driving. This feature simplifies the circuit and is conducive to the miniaturization of the power supply.

[0030] According to the embodiment of the present disclosure, the microcontroller unit realizes closed-loop feedback by performing PID calculation, thereby adjusting the power output size or changing the output current direction in real time.

[0031] According to an embodiment of the present disclosure, the magnet power supply also includes an instruction receiving unit for receiving a current correction instruction issued by a host computer and transmitting it to a microcontroller unit, so that the microcontroller unit sends a PWM control signal to control the power conversion unit to output a target current value.

[0032] According to an embodiment of the present disclosure, the instruction receiving unit includes an optical fiber communication module and an Ethernet communication module.

[0033] According to an embodiment of the present disclosure, the magnet power supply further includes an ADC conversion module, which is used to convert current sampling and voltage sampling results into digital signals.

[0034] According to another embodiment of the present disclosure, Figure 4 As shown, a correction method for a magnet power supply based on any one of the above items is provided, comprising: operations S1-S4. S1: voltage sampling of the input voltage and output voltage of the magnet power supply respectively; S2: current sampling of the output of the magnet power supply; S3: inputting a correction instruction including a target current value through a host computer; and S4: adjusting a PWM control signal according to the voltage sampling result, the current sampling result, and the correction instruction until a target output result is obtained.

[0035] More specifically: the target current value can be input through Ethernet or optical port; the controller receives the instruction to set the current value and parses the set value; the controller obtains high-precision ADC data through the SPI bus and performs algorithm processing, and the processing result will change the PWM output duty cycle; the change of PWM duty cycle will cause the change of output current, and then the collected high-precision ADC data will also change accordingly; repeating the above steps can achieve high-speed update and fast correction of the power supply output target current value. The current step response time can be measured by an oscilloscope, which is 36.56μs.

[0036] The microcontroller unit of the fast correction magnet power supply disclosed in the present invention has a main frequency of 170MHz and a high-resolution timer (HRTIM) (resolution 184ps), adopts a single-precision floating point unit (FPU) and implements a complete set of digital signal processing (DSP) instructions, which meets the needs of high-precision PWM regulators and high-speed computing controllers. Compared with the traditional fast correction power supply using FPGA as the main controller, the circuit is complicated and the peripheral circuit is simpler. The present invention uses the Ethernet chip W5500 and the optical fiber transceiver as the remote control terminal of the power supply.

[0037] The present invention integrates the control part microcontroller unit and the power part (power conversion unit, DCCT, input / output voltage sampling unit) on a 210mm*80mm board, and uses circuit board grooving and component isolation solutions to isolate power conversion heat and control signals. At the same time, precise acquisition and measurement signals and PWM signals are connected internally over a short distance, which effectively improves the dynamic response and electromagnetic compatibility of the power supply, simplifies the circuit structure design, and improves system reliability.

[0038] In response to the demand for fast correction magnet power supply in fast track feedback system, the present invention discloses the industry's first fast correction magnet power supply based on GaN HEMT power core and single-power supply PCB type DCCT, etc. The power supply combines 20-bit wide ADC, efficient control software and dynamic PID regulator, and its performance index is better than the current fast correction power supply. At the same time, it is small, efficient, modular and low-cost, and easy to assemble and maintain. The present invention discloses a 60V / ±20A fast correction magnet power supply based on GaN HEMT as a power device. For a load magnet inductance of 1mH, the frequency response of the input signal reaches 11kHz. At the same time, for magnet loads with different inductance values ​​within 10mH, the response frequency can also reach 5kHz by adjusting the control parameters; a high-speed optical fiber communication module is used to obtain a maximum data transmission delay of 7.2us; a power loop bandwidth of up to 250kHz has a good suppression effect on the jitter on the input and output sides of the power supply, and the application of a high-precision low-drift acquisition unit ensures that the long-term stability of the output current can reach 13ppm; thanks to the application of GaN devices, the response speed for a step current of 0.1A is within 40us, and the step response of a large current of 1.0A is tested for the first time by an oscilloscope (such as Figure 5 As shown in the figure, the total delay from given current to steady current output is controlled within 60us, which meets the fast track feedback system's requirement to suppress abnormal beam disturbances.

[0039] 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.

[0040] Based on the above description, those skilled in the art should have a clear understanding of the fast correction magnet power supply and correction method based on GaN HEMT disclosed in the present invention.

[0041] In summary, the present disclosure provides a fast correction magnet power supply and correction method based on GaN HEMT. The power supply uses GaN HEMT as a power device. The high frequency characteristics of GaN HEMT can greatly improve the power density of the power supply. Secondly, under the same rated voltage, GaN HEMT has lower conduction loss, which can improve conversion efficiency and improve system reliability and service life. The use of GaN HEMT can reduce the overall system size and weight, and greatly improve the power supply performance.

[0042] It should be noted that, in this document, unless otherwise specified, “a” element is not limited to a single element, but may include one or more elements.

[0043] In addition, in this document, unless otherwise specified, ordinal numbers such as "first" and "second" are only used to distinguish multiple components with the same name, and do not indicate that there is a hierarchy, level, execution order, or process order between them. A "first" component and a "second" component may appear together in the same component, or appear in different components. The presence of a component with a larger ordinal number does not necessarily indicate the presence of another component with a smaller ordinal number.

[0044] In this document, unless otherwise specified, the so-called feature A "or" or "and / or" (and / or) feature B means that A exists alone, B exists alone, or A and B exist at the same time; the so-called feature A "and" (and) or "and" (and) or "and" (and) feature B means that A and B exist at the same time; the so-called "include", "comprise", "have" and "contain" mean including but not limited to these.

[0045] In addition, in this document, the terms "upper", "lower", "left", "right", "front", "back", or "between" are only used to describe the relative positions between multiple elements, and can be extended to include translation, rotation, or mirroring. In addition, in this document, unless otherwise specified, "an element is on another element" or similar descriptions do not necessarily mean that the element contacts the other element.

[0046] 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.

[0047] 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 fast correction magnet power supply based on GaN HEMT, comprising: An AC-DC conversion unit, used for converting a grid voltage into a DC input voltage; A power conversion unit is used to convert the DC input voltage into power and output the power to the magnet load; DCCT, used for current sampling of the power output; An input / output voltage sampling unit, used to sample the input and output voltages of the power conversion unit respectively; as well as The micro control unit is used to output and adjust the PWM control signal acting on the power conversion unit in real time according to the received correction instruction, the current sampling result and the voltage sampling result, so as to achieve stable output of the magnet power supply.

2. The magnet power supply according to claim 1, wherein the power conversion unit is based on a topology of an H-type dual synchronous BUCK converter.

3. The magnet power supply according to claim 2, wherein the power conversion unit comprises two half-bridge power stage modules based on GaN HEMT, namely a first half-bridge power stage module and a second half-bridge power stage module, wherein: The first half-bridge power stage module includes a first GaN HEMT and a second GaN HEMT arranged in parallel, respectively used to receive a first high-order PWM control signal H1 and a first low-order PWM control signal L1 sent by the power conversion unit; The second half-bridge power stage module includes a third GaN HEMT and a fourth GaN HEMT arranged in parallel, and are used to receive a second high-order PWM control signal H2 and a second low-order PWM control signal L2 of the power conversion unit respectively; The outputs of the first half-bridge power stage module and the second half-bridge power stage module are both connected to both ends of the magnetic load.

4. According to the magnet power supply of claim 2, the first high-order PWM control signal H1 and the second high-order PWM control signal H2 are two independent PWM signals directly generated by the microcontroller unit, and the first low-order PWM control signal L1 and the second low-order PWM control signal L2 are obtained by performing high-ground level complementary processing on the first high-order PWM control signal H1 and the second high-order PWM control signal H2, and inserting dead time.

5. According to the magnet power supply of claim 4, in the combination of the first high-order PWM control signal H1 and the second low-order PWM control signal L2, or the second high-order PWM control signal H2 and the first low-order PWM control signal L1, the situation of being at high level at the same time will not occur, so no current output will be generated; when the duty cycle of the first high-order PWM control signal H1 is greater than the duty cycle of the second high-order PWM control signal H2, there will be a moment when the first high-order PWM control signal H1 and the second low-order PWM control signal L2 are at high level at the same time, thereby obtaining a positive current output; on the contrary, when the duty cycle of the first high-order PWM control signal H1 is less than the duty cycle of the second high-order PWM control signal H2, at certain moments the second high-order PWM control signal H2 and the first low-order PWM control signal L1 will be at high level at the same time, thereby generating a negative current output; for the situation where a larger current output is required, the duty cycles of the first high-order PWM control signal H1 and the second high-order PWM control signal H2 can be adjusted simultaneously to enhance the current output and dynamic response performance.

6. According to the magnet power supply of claim 1, the micro control unit realizes closed-loop feedback by performing PID calculation, and adjusts the power output size or changes the output current direction in real time.

7. The magnet power supply according to claim 1 further includes an instruction receiving unit for receiving a current correction instruction issued by a host computer and transmitting it to a microcontroller unit, so that the microcontroller unit sends a PWM control signal to control the power conversion unit to output a target current value.

8. The magnet power supply according to claim 1, wherein the instruction receiving unit comprises an optical fiber communication module and an Ethernet communication module.

9. The magnet power supply according to claim 1, further comprising an ADC conversion module, wherein the ADC conversion module is used to convert current sampling and voltage sampling results into digital signals.

10. A method for calibrating a magnet power supply according to any one of claims 1 to 9, comprising: The input voltage and output voltage of the magnet power supply are sampled respectively; Current sampling is performed on the output of the magnet power supply; Input correction instructions including target current value through the host computer; as well as The PWM control signal is adjusted according to the voltage sampling result, the current sampling result, and the correction instruction until the target output result is obtained.

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