Gradient power amplifier and control method thereof, and magnetic resonance imaging system

Abstract

The present application relates to a gradient power amplifier and a control method thereof, and a magnetic resonance imaging system. The gradient power amplifier comprises: a control module having a first interface, a second interface, a third interface and a fourth interface, wherein the first interface and the third interface are used to output control data; N power modules are used to receive the control data and output a gradient current to the gradient coil according to the control data, wherein N≥2; and a power module is connected to the N power modules to provide power to the N power modules; the first interface, the N power modules and the second interface are connected in series in sequence, thereby constructing a first annular data transmission path flowing from the first interface to the second interface; the third interface, the N power modules and the fourth interface are connected in series in sequence, thereby constructing a second annular data transmission path flowing from the third interface to the fourth interface; on the first data transmission path, the i-th power module is located downstream of the i-1-th power module; on the second data transmission path, the i-th power module is located upstream of the i-1-th power module; i=2, 3...N.

Description

Technical Field

[0001] The present application relates to a gradient power amplifier and a control method thereof, and a magnetic resonance imaging system. Background Art

[0002] Magnetic resonance imaging (MRI) is an imaging technology that uses the magnetic resonance phenomenon to obtain electromagnetic signals from the human body and reconstruct human body information. It has been widely used in the medical field because it has no ionizing radiation damage, high imaging contrast and resolution, and supports multiple parameter imaging and arbitrary direction cross-sectional imaging. The gradient power amplifier (GPA) is an important part of the magnetic resonance imaging system. The system drives the gradient coil to generate a linearly changing gradient magnetic field, thereby realizing functions such as layer selection and spatial encoding.

[0003] With years of development, MRI system products have become more and more diversified, and the requirements for gradient power amplifiers have become higher and higher. For example, some require high voltage and low current output, some require low voltage and high current output, and some require high voltage and high current output. In order to optimize cost control, gradient power amplifiers with different requirements often require major adjustments or even redesigns. This prolongs the R&D cycle and slows down market iteration. Summary of the invention

[0004] The technical problem solved by the present application is to provide a gradient power amplifier and a control method thereof, and a magnetic resonance imaging system.

[0005] The technical solution of this application is:

[0006] In a first aspect, the present application proposes a gradient power amplifier, comprising:

[0007] A control module, the control module having a corresponding first interface and a second interface, and a corresponding third interface and a fourth interface, wherein the first interface and the third interface are used to output control data;

[0008] N power modules, each of which is used to receive the control data and output a gradient current to a gradient coil according to the control data, wherein N≥2; and

[0009] A power module, the power module is connected to the N power modules to provide power to the N power modules;

[0010] The first interface of the control module, the N power modules, and the second interface of the control module are connected in series in sequence, so as to construct a first annular data transmission path flowing from the first interface to the second interface;

[0011] The third interface of the control module, the N power modules and the fourth interface of the control module are connected in series in sequence, so as to construct a second annular data transmission path flowing from the third interface to the fourth interface;

[0012] On the first data transmission path, the i-th power module is located downstream of the i-1-th power module; on the second data transmission path, the i-th power module is located upstream of the i-1-th power module; wherein i=2, 3...N.

[0013] In an optional design, the power supply module is serially connected to both the first data transmission path and the second data transmission path;

[0014] On the first data transmission path, the power module is located downstream of the Nth power module; on the second data transmission path, the power module is located upstream of the Nth power module.

[0015] In an optional design, the gradient power amplifier further includes:

[0016] an output filter module, the output filter module being connected between the power module and the gradient coil and configured to filter the harmonic components of the gradient current; and

[0017] a current detection module, the current detection module is connected to both the output filter module and the gradient coil and the control module, so as to collect current data output by the output filter module and generate feedback data to be transmitted to the control module based on the current data, so that the control module can generate control data for adjusting the gradient current output by the power module based on the feedback data.

[0018] In an optional design, each of the power modules includes a synchronous counter and an execution delay comparator connected to each other, and each of the power modules includes a first level output interface and a second level output interface.

[0019] In a second aspect, the present application provides a magnetic resonance imaging system, comprising the gradient power amplifier as described in the first aspect.

[0020] In a third aspect, the present application provides a control method, applied to the gradient power amplifier as described in the first aspect, the control method comprising:

[0021] Controlling the control module to output a first control data frame to the first data transmission path through the first interface, and controlling the control module to output a second control data frame to the second data transmission path through the third interface; wherein the first control data frame and the second control data frame are the same data frame;

[0022] Obtaining the jth time difference between when the jth power module receives the first control data frame and when it receives the second control data frame, taking half of the jth time difference, to obtain the jth duration threshold; wherein j=1, 2, 3...N;

[0023] Controlling the control module to output a third control data frame to the first data transmission path through the first interface, and controlling the control module to output a fourth control data frame to the second data transmission path through the third interface; wherein the third control data frame and the fourth control data frame are the same data frame;

[0024] In response to the jth power module receiving any one of the third control data frame and the fourth control data frame for the first time, after delaying for the jth time length threshold, the jth power module is controlled to execute instructions in any one of the data frames.

[0025] In an optional design, the “obtaining a jth time difference between when the jth power module receives the first control data frame and when the jth power module receives the second control data frame, taking half of the jth time difference, and obtaining a jth duration threshold” includes:

[0026] In response to the j-th power module receiving any one of the first control data frame and the second control data frame for the first time, controlling the synchronization counter in the j-th power module to perform a first count upward from zero based on time;

[0027] In response to the j-th power module receiving the other data frame of the first control data frame and the second control data frame, stopping the first counting, obtaining the count value of the first counting, taking half of the count value, and obtaining a j-th counting threshold, wherein the j-th counting threshold corresponds to the j-th duration threshold;

[0028] The “in response to the jth power module receiving for the first time any one of the third control data frame and the fourth control data frame, after delaying the jth time length threshold, controlling the jth power module to execute the instruction in any one of the data frames” includes:

[0029] In response to the j-th power module receiving any one of the third control data frame and the fourth control data frame for the first time, controlling the synchronization counter to perform a second count upward from zero based on time;

[0030] In response to a count value of the second count being greater than or equal to the j-th count threshold, controlling the j-th power module to execute instructions in any one of the data frames.

[0031] In an optional design, after “controlling the control module to output the first control data frame to the first data transmission path through the first interface, and controlling the control module to output the second control data frame to the second data transmission path through the third interface”, the control method further includes:

[0032] Obtaining the N+1th time difference between when the power module receives the first control data frame and when the power module receives the second control data frame, taking half of the N+1th time difference to obtain the N+1th duration threshold;

[0033] After the step of “controlling the control module to output a third control data frame to the first data transmission path through the first interface, and controlling the control module to output a fourth control data frame to the second data transmission path through the third interface”, the control method further includes:

[0034] In response to the power module receiving any one of the third control data frame and the fourth control data frame for the first time, after delaying the N+1th time length threshold, the power module is controlled to execute instructions in any one of the data frames.

[0035] In an optional design, after the “in response to the jth power module receiving for the first time any one of the third control data frame and the fourth control data frame, after delaying the jth time length threshold, controlling the jth power module to execute the instruction in any one of the data frames”, the control method further includes:

[0036] In response to the j-th power module receiving the other data frame of the third control data frame and the fourth control data frame, the j-th power module is controlled to discard the other data frame.

[0037] In an optional design, the control method further includes:

[0038] Obtaining a second j-th time difference between when the j-th power module receives the third control data frame and when the j-th power module receives the fourth control data frame, taking half of the second j-th time difference to obtain a second j-th duration threshold;

[0039] Controlling the control module to output a fifth control data frame to the first data transmission path through the first interface, and controlling the control module to output a sixth control data frame to the second data transmission path through the third interface; wherein the fifth control data frame and the sixth control data frame are the same data frame;

[0040] In response to the jth power module receiving for the first time any one of the fifth control data frame and the sixth control data frame, after delaying for the second jth time length threshold, the jth power module is controlled to execute instructions in any one of the fifth control data frame and the sixth control data frame.

[0041] This application has at least the following beneficial effects:

[0042] The gradient power amplifier provided by the present application is configured with multiple power modules, and two opposite data transmission paths are established between these power modules and the control module in series, so that the control module can not only uniformly control the actions of each power module, but also uniformly obtain the status information of each power module, so that the control module can adjust the next output data according to the status information of each power module. In addition, multiple power modules are uniformly controlled by one control module, and the output performance of the gradient power amplifier can be quickly adjusted, such as cascading the power modules and outputting them to obtain a higher output voltage, or connecting the power modules in parallel to obtain a larger current output.

[0043] In addition, the gradient power amplifier provided by the present application can enable each power module to respond to the control instruction of the control module synchronously and as quickly as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present application, rather than limiting the present application.

[0045] Figure 1 It is a schematic block diagram of the application of a gradient power amplifier in one embodiment of the present application.

[0046] Figure 2 yes Figure 1 Another application schematic block diagram of a medium gradient power amplifier.

[0047] Figure 3 yes Figure 1 Another schematic block diagram of a medium gradient power amplifier application.

[0048] Figure 4It is a schematic diagram of data transmission between related devices in a gradient power amplifier in one embodiment of the present application.

[0049] Figure 5 It is a schematic diagram of the structure of the third control data frame and the fourth control data frame in one embodiment of the present application.

[0050] Figure 6 It is a schematic flow chart of a control method of a gradient power amplifier in one embodiment of the present application.

[0051] Figure 7 It is a schematic flow chart of a control method of a gradient power amplifier in another embodiment of the present application.

[0052] Figure 8 yes Figure 6 A schematic flow chart of step S602 in the illustrated embodiment.

[0053] Fig. 9 yes Figure 6 A schematic flow chart of step S604 in the illustrated embodiment.

[0054] Fig.10 It is a schematic block diagram of a control module in one embodiment of the present application.

[0055] Fig.11 It is a schematic block diagram of a power module in one embodiment of the present application.

[0056] Fig.12 It is a schematic block diagram of a power supply module in one embodiment of the present application.

[0057] Fig.13 It is a schematic block diagram of a current detection module in an embodiment of the present application.

[0058] Description of reference numerals:

[0059] 100-gradient power amplifier;

[0060] 1-control module, 2-power module, 3-power module, 4-output filter module, 5-current detection module, 6-gradient coil;

[0061] 1a-first interface, 1b-second interface, 1c-third interface, 1d-fourth interface;

[0062] L1-first data transmission path, L2-second data transmission path. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the embodiment of the present application will be clearly and completely described below in conjunction with the drawings of the embodiment of the present application. Obviously, the described embodiment is a part of the embodiment of the present application, rather than all the embodiments. Based on the described embodiment of the present application, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of this application. It can be understood that, in the absence of conflict, some technical means of the various embodiments described herein can be replaced or combined with each other.

[0064] In the description of the specification and claims of this application, if there are terms such as "first", "second", etc., they are only used to distinguish the objects described and do not have any order or technical meaning. Therefore, the objects defined as "first", "second", etc. may explicitly or implicitly include one or more of the objects. In addition, "one" or "a" and similar words do not indicate a quantitative limitation, but indicate the existence of at least one, and "multiple" means no less than two.

[0065] In the description of the specification and claims of this application, if there are terms such as "connect", "install", "fix", "contain", etc., unless otherwise specified, they should be understood in a broad sense. For example, "connection" can be a separate connection or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a non-detachable connection or a detachable connection. For another example, "contain" does not necessarily mean complete containment of the whole. The concept also includes the partial containment of a part protruding from the outside. For those skilled in the art, the specific meanings of the aforementioned terms in this application can be understood according to the specific circumstances.

[0066] In the description of the specification and claims of this application, if there are terms such as "upper", "lower", "horizontal" and the like indicating an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it is only for the convenience of describing the application clearly and simply, and does not indicate or imply that the elements referred to must have a specific direction, be constructed and operated in a specific orientation. These directional terms are relative concepts, used for relative description and clarification, and may change accordingly according to the change in the orientation of the components placed in the drawings. For example, if the device in the figure is turned over, the elements described as "below" other elements will be positioned "above" other elements.

[0067] In the description of the specification and claims of this application, if the terms "sequentially" or "in sequence" appear, for example, the phrase "A, B, C arranged sequentially" only indicates the arrangement order of elements A, B, C, and does not exclude the possibility of arranging other elements between A and B and / or between B and C.

[0068] In the description of the specification and claims of this application, if there is a term "based on" or "according to", it is used to describe one or more factors that affect the determination. The term does not exclude additional factors that affect the determination. That is, the determination may be based only on these factors or at least partially on these factors. For example, the phrase "based on A, B is determined". In this case, A is a factor that affects the determination of B. This phrase does not exclude that the determination of B may also be based on C.

[0069] In the description of the specification and claims of this application, the term "responsive to" and related terms refer to a signal or event being affected to a certain extent by another signal or event, but not necessarily completely or directly. If event A occurs "responsive to" event B, A may be directly or indirectly responsive to B. For example, the occurrence of B may eventually lead to the occurrence of A, but there may be other intermediate events and / or conditions. In other cases, B may not necessarily lead to the occurrence of A, and A may occur even if B has not yet occurred. In addition, the term "responsive to" may also mean "at least partially responsive to".

[0070] Now, embodiments of the present application are described with reference to the accompanying drawings.

[0071] Please refer to Figure 1 , the embodiment of the present application provides a gradient power amplifier, which includes a control module 1, a power module 3 and N power modules 2, N can be any natural number ≥ 2, for example, Figure 1 In another embodiment, N=3. Figure 4 As shown, N=4.

[0072] Please refer to Figure 1 Combined with Figure 4 The control module 1 has at least a first interface 1a, a second interface 1b, a third interface 1c and a fourth interface 1d, wherein the first interface 1a corresponds to the second interface 1b, the third interface 1c corresponds to the fourth interface 1d, and the first interface and the third interface are used to output control data.

[0073] The power module 2 is used to receive control data and output gradient current to the gradient coil 6 according to the control data.

[0074] The power module 3 is connected to the N power modules 2 to provide power to the N power modules 2 .

[0075] Please refer to Figure 1 Combined with Figure 4, the first interface 1a of the control module 1, the N power modules 2 and the second interface 1b of the control module 1 are connected in series through optical fibers, thereby constructing a first annular data transmission path L1 flowing from the first interface 1a to the second interface 1b. The third interface 1c of the control module 1, the N power modules 2 and the fourth interface 1d of the control module 1 are connected in series through optical fibers, thereby constructing a second annular data transmission path L2 flowing from the third interface 1c to the fourth interface 1d. Moreover, on the first data transmission path L1, the i-th power module 2 is located downstream of the i-1th power module 2; on the second data transmission path L2, the i-th power module 2 is located upstream of the i-1th power module 2; i=2, 3, 4...N.

[0076] The first data transmission path L1 and the second data transmission path L2 are used to transmit the control data output by the control module 1 to each power module 2 .

[0077] During operation, the N power modules 2 receive the control data output from the control module 1 and respectively perform their own response actions based on the control data. Figure 6 Combined with Figure 1 and Figure 4 This embodiment also provides a control method for the above-mentioned gradient power amplifier, and the control method includes:

[0078] S601, the control module 1 outputs a first control data frame to the first data transmission path L1 through the first interface 1a, and the control module 1 outputs a second control data frame to the second data transmission path L2 through the third interface 1c; wherein the first control data frame and the second control data frame are the same data frame.

[0079] The so-called “same data frame” means that the first control data frame and the second control data frame have the same control instructions.

[0080] S602, obtaining the jth time difference between when the jth power module 2 receives the first control data frame and when it receives the second control data frame, taking half of the jth time difference to obtain the jth duration threshold; wherein j=1, 2, 3...N.

[0081] It can be understood that j=1, 2, 3...N, which means that the time difference between each power module 2 among the N power modules 2 receiving the first control data frame and the time difference between each power module 2 receiving the second control data frame is to be obtained. Each power module 2 has its own duration threshold respectively - the first power module 2 corresponds to the first duration threshold, and the third power module 2 corresponds to the third duration threshold.

[0082] In the above S601, the control module 1 simultaneously outputs two identical data frames, the first control data frame and the second control data frame, which are transmitted in opposite directions along the first data transmission path L1 and the second data transmission path L2, respectively. It can be understood that since the positions of the power modules 2 on the two data transmission paths are different, the time when the power modules 2 receive the first data frame and the second data frame is different. For example, Figure 4 In the described embodiment, with the control module 1 as the starting point, the four power modules 2 along the direction are the first power module 2, the second power module 2, the third power module 2, and the fourth power module 2. Then, the first power module 2 will receive the first data frame first, and then the second data frame. There is a time difference between the time when the first power module 2 receives the first data frame and the second data frame - the first time difference (for example, 5 microseconds), half of the first time difference is taken and recorded as the first duration (for example, 2.5 microseconds); the fourth power module 2 will receive the second data frame first, and then the first data frame. There is also a time difference between the time when the fourth power module 2 receives the first data frame and the second data frame - recorded as the fourth time difference (for example, 6 microseconds), half of the fourth time difference is taken and recorded as the fourth duration (for example, 3 microseconds); in addition, the first power module 2 receives the first data frame before the second power module 2, and receives the second data frame after the second power module 2.

[0083] S603, while controlling the control module 1 to output a third control data frame to the first data transmission path L1 through the first interface 1a, the control module 1 outputs a fourth control data frame to the second data transmission path L2 through the third interface 1c; wherein the third control data frame and the fourth control data frame are the same data frame.

[0084] It can be understood that the two identical control data frames, the third data frame and the fourth data frame, outputted simultaneously by the control module 1 are synchronously transmitted along the first data transmission path L1 and the second data transmission path L2, respectively. Figure 4 In the example, the first power module 2 will receive the third data frame first and then the fourth data frame; and the first power module 2 will receive the third data frame before the second power module 2 and will receive the fourth data frame after the second power module 2.

[0085] S604, in response to the j-th power module 2 receiving for the first time any one of the third control data frame and the fourth control data frame, after delaying for the j-th time length threshold, controls the j-th power module 2 to execute the instructions in any one of the data frames (i.e., any one of the data frames mentioned in S604).

[0086] It should be noted that the above “the jth power module 2 receives any one of the third control data frame and the fourth control data frame for the first time” has the following meaning: the third control data frame and the fourth control data frame are regarded as two identical data frames X, and the jth power module 2 will receive these two data frames X successively. Only when the jth power module 2 receives the data frame X for the first time (the data frame X may be the third control data frame or the fourth control data frame), the above action will be performed—after delaying the jth time length threshold, the jth power module 2 is controlled to execute the instruction in the data frame X. Then, when the jth power module 2 receives the data frame X for the second time (for example, the data frame X received for the first time is the fourth data frame, and the data frame X received for the second time is the third control data frame), the above action does not need to be performed.

[0087] Normally, the user does not want the jth power module 2 to immediately execute or delay the execution of the instruction of the later data frame X when it receives the data frame X for the second time. Figure 7 In another embodiment, after “in response to the j-th power module 2 receiving any one of the third control data frame and the fourth control data frame for the first time, after delaying the j-th time length threshold, controlling the j-th power module 2 to execute the instruction in any one of the data frames”, the control method further includes:

[0088] S705 , in response to the jth power module 2 receiving the other data frame of the third control data frame and the fourth control data frame, controlling the jth power module 2 to discard the other data frame.

[0089] The so-called “discard” means “not execute”, and the other data frame will still be transmitted downstream along the data transmission path.

[0090] In the aforementioned S603, the two identical data frames simultaneously output by the control module 1, the third control data frame and the fourth control data frame, are synchronously transmitted along the first data transmission path L1 and the second data transmission path L2, respectively. Since the positions of the power modules 2 on the two data transmission paths are different, the time when the power modules 2 receive the third control data frame and the fourth control data frame is different. If each power module 2 immediately executes the control instruction in the response data frame and responds once it receives the third control data frame or the fourth control data frame, the action pace of each power module 2 will be seriously out of sync. In this regard, the present embodiment sets the above control strategy to ensure that each power module 2 has a uniform action pace.

[0091] Since the physical structure of the first data transmission path L1 and the second data transmission path L2 has not changed, the transmission speed of the data frame between any two adjacent nodes on the first data transmission path L1 and the second data transmission path L2 remains unchanged, and the transmission time of the third control data between the i-1th power module 2 and the i-th power module 2 is equal to the transmission time of the fourth control data between the i-th power module 2 and the i-1th power module 2. Figure 4 In the embodiment shown, assuming that the number of power modules 2 is expanded to 10, that is, N=10, then usually the first power module 2 and the second power module 2 first receive the third control data frame transmitted via the first data transmission path L1, and the tenth power module 2 and the ninth power module 2 first receive the fourth control data frame transmitted via the second data transmission path L2. Combined with the description of S601 and S602, it can be known that the time when the fourth control data frame arrives at the first power module 2 is the time point when the first power module 2 receives the third control data frame and then delays by the first time difference, and the time when the fourth control data frame arrives at the second power module 2 is the time point when the second power module 2 receives the third control data frame and then delays by the second time difference, and the first time difference is greater than the second time difference; the time when the third control data frame arrives at the tenth power module 2 is the time point when the tenth power module 2 receives the fourth control data frame and then delays by the tenth time difference, and the time when the third control data frame arrives at the ninth power module 2 is the time point when the ninth power module 2 receives the fourth control data frame and then delays by the ninth time difference, and the tenth time difference is greater than the ninth time difference. Through simple mathematical calculations, it can be known that the duration of the third control data frame transmitted from the first interface 1a to the first power module 2 + half of the first time difference = the duration of the third control data frame transmitted from the first interface 1a to the second power module 2 + half of the second time difference = the duration of the fourth control data frame transmitted from the third interface 1c to the ninth power module 2 + half of the ninth time difference = the duration of the fourth control data frame transmitted from the third interface 1c to the tenth power module 2 + half of the tenth time difference. The aforementioned half of the first time difference, half of the second time difference, half of the ninth time difference and half of the tenth time difference correspond to the first time duration, the second time duration, the ninth time duration and the tenth time duration in S602, respectively.

[0092] In summary, the duration of the transmission of the first data frame in the third control data frame and the fourth data frame from the first interface 1a or the third interface 1c to the i-th power module 2 + the i-th duration = the duration of the transmission of the first data frame in the third control data frame and the fourth data frame from the first interface 1a or the third interface 1c to the i-1-th power module 2 + the i-1-th duration, i=2, 3, 4...N. More importantly, the duration of receiving the first data frame in the third control data frame and the fourth data frame is very close to (slightly less than) or even completely equal to the duration of the transmission of the first data frame from the first interface 1a or the third interface 1c to the i-th power module 2 + the i-th duration among all the power modules 2. In this way, each power module 2 can respond to the control instruction of the control module synchronously and as quickly as possible.

[0093] It should be noted that, in some embodiments, it is possible that one of the power modules 2 will receive the third control data frame and the fourth data frame at the same time. In this case, the j-th duration threshold corresponding to the power module 2 is zero.

[0094] In this embodiment, each power module 2 includes a synchronous counter and an execution delay comparator connected to each other. Correspondingly, in the above S602, "obtaining the jth time difference between the jth power module 2 receiving the first control data frame and the second control data frame, taking half of the jth time difference, and obtaining the jth duration threshold" can be further optimized to include:

[0095] S6021, in response to the j-th power module 2 receiving any one of the first control data frame and the second control data frame for the first time, controlling the synchronization counter of the j-th power module 2 to perform a first count upward from zero based on time;

[0096] S6022, in response to the j-th power module 2 receiving the first control data frame and another data frame in the second control data frame, stop the first count, obtain the count value of the first count, take half of the count value of the first count, and obtain the j-th count threshold, the j-th count threshold corresponds to the j-th duration threshold.

[0097] Correspondingly, in the above S604, “in response to the j-th power module 2 receiving any one of the third control data frame and the fourth control data frame for the first time, after delaying the j-th time length threshold, controlling the j-th power module 2 to execute the instruction in any one of the data frames” can be further optimized to include:

[0098] S6041, in response to the j-th power module 2 receiving any one of the third control data frame and the fourth control data frame for the first time, controlling the synchronization counter to perform a second count upward from zero based on time;

[0099] S6042, in response to the count value of the second count being greater than or equal to the jth count threshold, controlling the jth power module 2 to execute the instruction in any one of the data frames (ie, any one of the data frames mentioned in the aforementioned S6041).

[0100] Please refer to Figure 1 Combined with Figure 4 In this embodiment, the power module 3 is serially connected to both the first data transmission path L1 and the second data transmission path L2. On the first data transmission path L1, the power module 3 is located downstream of the Nth power module 2; on the second data transmission path L2, the power module 3 is located upstream of the Nth power module 2. Specifically, the power module 3 is serially connected to the first data transmission path L1 between the Nth power module 2 and the second interface 1b of the control module 1, and to the second data transmission path L2 between the third interface 1c of the control module 1 and the Nth power module 2.

[0101] Based on the above design, the power module 3 can also receive the control data output by the control module 1 to make a response action based on the control data. Correspondingly, the control method provided in this embodiment can also be optimized as follows.

[0102] Specifically, after “controlling the control module 1 to output the first control data frame to the first data transmission path L1 through the first interface 1a, and controlling the control module 1 to output the second control data frame to the second data transmission path L2 through the third interface 1c”, that is, after the above S601, the control method provided in this embodiment may further include:

[0103] The N+1th time difference between when the power module 3 receives the first control data frame and when the power module 3 receives the second control data frame is obtained, and half of the N+1th time difference is taken to obtain the N+1th duration threshold.

[0104] Furthermore, after “controlling the control module 1 to output the third control data frame to the first data transmission path L1 through the first interface 1a, and controlling the control module 1 to output the fourth control data frame to the second data transmission path L2 through the third interface 1c”, that is, after the above S603, the control method provided in this embodiment may further include:

[0105] In response to the power module 3 receiving for the first time any one of the third control data frame and the fourth control data frame (considering the position of the power module 3, the power module 3 usually receives the fourth control data frame first), after delaying for the above-mentioned N+1 time length threshold, the power module 3 is controlled to execute the instructions in any one of the data frames (that is, any one of the data frames mentioned in this paragraph, usually the fourth control data frame).

[0106] Please refer to Figure 5, the data frame consists of a frame header, a frame trailer and N+1 data slots. The frame header contains bit synchronization, frame synchronization information and a frame number, and the frame trailer contains frame check information. The frame number increases after each control data frame transmission. When the control data frame is sent from the control module 1, each data slot contains the control data that the control module 1 (master node) wants to pass to the corresponding slave node (power module 2 and power module 3). After each slave node receives the control data frame, it stores the control data of the corresponding data slot of this node, and sets the content of the corresponding data slot as the status information data of this node, and continues to pass it down.

[0107] In addition, please refer to Figure 1 In this embodiment, the gradient power amplifier also includes an output filtering module 4 and a current detection module 5.

[0108] The output filter module 4 is connected between the power module 2 and the gradient coil 6 and is used to filter the harmonic components of the gradient current.

[0109] The current detection module 5 is connected between the output filter module 4 and the gradient coil 6, and is also connected to the control module 1, so as to collect the current data output by the output filter module 4, and generate feedback data to be transmitted to the control module 1 based on the current data, so that the control module 1 can generate control data for adjusting the gradient current output by the power module 2 based on the feedback data.

[0110] Similar to the conventional power module 2, in this embodiment, each power module 2 includes a first level output interface and a second level output interface. The voltage between the first level output interface and the second level output interface can usually be adjusted in response to a control instruction. For example, the power module 2 adjusts the voltage between the first level output interface and the second level interface in response to the control data generated by the control module 1 received by the power module 2.

[0111] After the control module 1 outputs the third and fourth control data frames, it usually continues to periodically output other control data frames to the two data transmission paths respectively. If each power module 2 still uses the aforementioned j-th time length threshold as the delay time for executing the control instruction, there will inevitably be a problem of error accumulation. In order to solve this problem, in other embodiments, the control method further includes:

[0112] Obtain the second j-th time difference between when the j-th power module 2 receives the third control data frame and when it receives the fourth control data frame, and take half of the second j-th time difference to obtain the second j-th duration threshold;

[0113] While the control module 1 outputs the fifth control data frame to the first data transmission path through the first interface, the control module outputs the sixth control data frame to the second data transmission path through the third interface; wherein the fifth control data frame and the sixth control data frame are the same data frame;

[0114] In response to the jth power module receiving any one of the fifth control data frame and the sixth control data frame for the first time, after delaying the second jth time length threshold, the jth power module is controlled to execute the instructions in any one of the data frames (i.e., "any one of the data frames" mentioned in this paragraph).

[0115] Furthermore, each power module 2 will update the next delay time threshold each time it receives a late data frame among two identical and corresponding control data frames on the two data transmission paths.

[0116] The control module 1 can be purchased from the market and slightly debugged, or it can be used Fig.10 The structure shown. Fig.10 In the embodiment, the control module 1 mainly includes a crystal oscillator, a control module 1 processor, a liquid crystal display (LCD) and multiple groups of photoelectric converters, and the control module 1 processor mainly includes a communication controller and a state controller. The instructions sent by the MRI system and the feedback data fed back by the current detection module 5 enter the control module 1 processor through the photoelectric converter, and the control data (such as the third control data and the fourth control data mentioned above) for the power module 2 and the power supply module 3 are obtained after being calculated by the output controller, and are sent out through the communication controller and the photoelectric converter. The state information of the power module 2 and the power supply module 3 returned from the communication controller (especially the second interface 1b and the fourth interface 1d connected to the communication controller) is analyzed by the state controller, displayed through the state display interface, and also fed back to the MRI system through the system command interface, and also enters the output controller to participate in adjusting the next output or making it enter the protection state. The control module 1 processor is mainly implemented by FPGA.

[0117] Power module 2 can be purchased from the market and slightly debugged, or it can be used Fig.11 The structure shown. Fig.11In the embodiment, the power module 2 mainly includes two pairs (4) of photoelectric converters, a power module 2 processor, a crystal oscillator, M power full bridges and their drivers (M≥1, the typical value is 5), as well as a small signal power supply and a water cooling plate. One pair of the two pairs of photoelectric converters is used to connect the upstream node, and the other pair is used to connect the downstream node. The power module 2 processor is implemented by a programmable logic device (CPLD or FPGA), which mainly includes a communication controller, a PWM generator, and a state monitor. The outputs of the M power full bridges are cascaded and output to the outside, and each level of the power full bridge is provided with a high power input by a set of isolated bus DC power supplies. The small signal power supply powers the electronic devices in the power module 2. The water cooling plate provides heat dissipation for the power full bridge.

[0118] The power module 3 can be purchased from the market and slightly debugged, or it can be used Fig.12 The structure shown. Fig.12 In the embodiment, the power module 3 is mainly composed of two pairs (4) of photoelectric converters, a power module 3 processor, a crystal oscillator, M high-power DC power modules 3 (M≥1, a typical value is 5), and a low-power multi-channel DC power supply. One pair of the two pairs of photoelectric converters is used to connect the upstream node, and the other pair is used to connect the downstream node. The power module 3 processor is implemented by a programmable logic device (CPLD or FPGA), which mainly includes a communication controller, a power controller and a power monitor. The M high-power DC power modules 3 provide power to the M power full bridges of the power module 2. The M high-power DC power modules 3 can also be replaced by a power transformer with M output windings and a rectifier filter circuit. The low-power multi-channel DC power supply provides the power required for the control and signal links to this module and other modules.

[0119] The current detection module 5 can be purchased from the market and slightly debugged, or it can be used Fig.13 The structure shown. Fig.13 In the embodiment, the current detection module 5 mainly includes a crystal oscillator, a photoelectric converter, a current detection module 5 processor and at least one current sensor. The current detection module 5 processor is implemented by a programmable logic device (CPLD or FPGA), which mainly includes a control module 1 interface, a sensor signal conditioner, and a sensor interface. The current detection module 5 can be cascaded. After the previous stage signal enters the current detection module 5 processor through the photoelectric converter, it is pre-processed and serially connected with the current sensor signal entering the current stage through the sensor interface by the signal conditioner, and then sent to the next stage current detection module 5 or control module 1 through the control module 1 interface.

[0120] The output filter module 4 is mainly composed of parallel filter inductors.

[0121] The gradient power amplifier provided in this embodiment can cascade its power modules 2 and output them, thereby obtaining a higher output voltage. Figure 2 The power modules 2 can also be connected in parallel to obtain a higher current output. Figure 3 .

[0122] In addition, an embodiment of the present application further provides a magnetic resonance imaging system, which includes a gradient power amplifier with the above structure.

Claims

1. A gradient power amplifier, comprising: A control module, the control module having a corresponding first interface and a second interface, and a corresponding third interface and a fourth interface, wherein the first interface and the third interface are used to output control data; N power modules, each of which is used to receive the control data and output a gradient current to a gradient coil according to the control data, wherein N≥2; and A power module, the power module is connected to the N power modules to provide power to the N power modules; an output filter module, the output filter module being connected between the power module and the gradient coil and being used for filtering the harmonic components of the gradient current; The first interface of the control module, the N power modules, and the second interface of the control module are connected in series in sequence, so as to construct a first annular data transmission path flowing from the first interface to the second interface; The third interface of the control module, the N power modules and the fourth interface of the control module are connected in series in sequence, so as to construct a second annular data transmission path flowing from the third interface to the fourth interface; On the first data transmission path, the i-th power module is located downstream of the i-1-th power module; on the second data transmission path, the i-th power module is located upstream of the i-1-th power module; wherein i=2, 3...N.

2. The gradient power amplifier according to claim 1, characterized in that: The power supply module is serially connected to both the first data transmission path and the second data transmission path; On the first data transmission path, the power module is located downstream of the Nth power module; on the second data transmission path, the power module is located upstream of the Nth power module.

3. The gradient power amplifier according to claim 1, characterized in that: Each of the power modules includes a synchronous counter and an execution delay comparator connected to each other, and each of the power modules includes a first level output interface and a second level output interface.

4. A magnetic resonance imaging system, characterized in that: Comprising the gradient power amplifier as claimed in any one of claims 1 to 3.

5. A control method, applied to the gradient power amplifier according to any one of claims 1 to 3, characterized in that: The control method comprises: Controlling the control module to output a first control data frame to the first data transmission path through the first interface, and controlling the control module to output a second control data frame to the second data transmission path through the third interface; wherein the first control data frame and the second control data frame are the same data frame; Obtaining the jth time difference between when the jth power module receives the first control data frame and when it receives the second control data frame, taking half of the jth time difference, to obtain the jth duration threshold; wherein j=1, 2, 3...N; Controlling the control module to output a third control data frame to the first data transmission path through the first interface, and controlling the control module to output a fourth control data frame to the second data transmission path through the third interface; wherein the third control data frame and the fourth control data frame are the same data frame; In response to the jth power module receiving any one of the third control data frame and the fourth control data frame for the first time, after delaying the jth time length threshold, the jth power module is controlled to execute instructions in any one of the data frames.

6. The control method according to claim 5, characterized in that: The control method is applied to the gradient power amplifier as claimed in claim 4; The "obtaining the jth time difference between when the jth power module receives the first control data frame and when it receives the second control data frame, taking half of the jth time difference to obtain the jth duration threshold" includes: In response to the j-th power module receiving any one of the first control data frame and the second control data frame for the first time, controlling the synchronization counter in the j-th power module to perform a first count upward from zero based on time; In response to the j-th power module receiving the other data frame of the first control data frame and the second control data frame, stopping the first counting, obtaining the count value of the first counting, taking half of the count value, and obtaining a j-th counting threshold, wherein the j-th counting threshold corresponds to the j-th duration threshold; The “in response to the jth power module receiving for the first time any one of the third control data frame and the fourth control data frame, after delaying the jth time length threshold, controlling the jth power module to execute the instruction in any one of the data frames” includes: In response to the j-th power module receiving any one of the third control data frame and the fourth control data frame for the first time, controlling the synchronization counter to perform a second count upward from zero based on time; In response to a count value of the second count being greater than or equal to the j-th count threshold, controlling the j-th power module to execute instructions in any one of the data frames.

7. The control method according to claim 5, characterized in that: The control method is applied to the gradient power amplifier as claimed in claim 2; After the step of "controlling the control module to output the first control data frame to the first data transmission path through the first interface, and controlling the control module to output the second control data frame to the second data transmission path through the third interface", the control method further includes: Obtaining the N+1th time difference between when the power module receives the first control data frame and when the power module receives the second control data frame, taking half of the N+1th time difference to obtain the N+1th duration threshold; After the step of "controlling the control module to output a third control data frame to the first data transmission path through the first interface, and controlling the control module to output a fourth control data frame to the second data transmission path through the third interface", the control method further includes: In response to the power module receiving any one of the third control data frame and the fourth control data frame for the first time, after delaying the N+1th time length threshold, the power module is controlled to execute instructions in any one of the data frames.

8. The control method according to claim 5, characterized in that: After the step of "in response to the jth power module receiving for the first time any one of the third control data frame and the fourth control data frame, after delaying the jth time length threshold, controlling the jth power module to execute the instruction in any one of the data frames", the control method further includes: In response to the j-th power module receiving the other data frame of the third control data frame and the fourth control data frame, the j-th power module is controlled to discard the other data frame.

9. The control method according to any one of claims 5 to 8, characterized in that: The control method further comprises: Obtaining a second j-th time difference between when the j-th power module receives the third control data frame and when the j-th power module receives the fourth control data frame, taking half of the second j-th time difference to obtain a second j-th duration threshold; Controlling the control module to output a fifth control data frame to the first data transmission path through the first interface, and controlling the control module to output a sixth control data frame to the second data transmission path through the third interface; wherein the fifth control data frame and the sixth control data frame are the same data frame; In response to the jth power module receiving for the first time any one of the fifth control data frame and the sixth control data frame, after delaying for the second jth time length threshold, the jth power module is controlled to execute instructions in any one of the fifth control data frame and the sixth control data frame.

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