Transformer design methods

Abstract

The transformer design method provided by this invention involves repeatedly performing the following steps until a preset condition is met: determining the output voltage difference of any pair of secondary windings in each secondary winding set based on the phase shift angle and number of turns of each secondary winding in each secondary winding set; adjusting the phase shift angle of at least one secondary winding in the secondary winding set when the preset condition is not met; wherein, the phase shift angle when the preset condition is met is the final phase shift angle of the secondary winding; and the number of turns corresponding to the final phase shift angle is the final number of turns of the secondary winding. This invention solves the problem of excessive voltage difference caused by rounding the number of turns of the secondary winding of the transformer by continuously adjusting and iterating the phase shift angle of the secondary winding of the transformer, realizing input voltage regulation and current sharing of the rectifier bridge arm, and effectively reducing the size and cost of the charging system.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and more particularly to a transformer design method. Background Technology

[0002] Existing centralized high-power electric vehicle charging systems typically connect the power grid to the primary winding of a multi-pulse transformer. Multiple secondary windings of the multi-pulse transformer are then connected to an AC-DC charging module (also known as a power conversion unit), which in turn connects to the device being charged. However, due to the rounding effect of the number of turns in the secondary winding of the multi-pulse transformer, the output voltage of the secondary winding becomes unequal. This leads to uneven current distribution in the input current of the rectifier bridge arms in the AC-DC charging module. This uneven current distribution increases the current stress on the diodes, requiring sufficient margin in the components, which is detrimental to rectifier bridge selection and capacitor ripple current selection.

[0003] In the prior art, in order to achieve current sharing among the input rectifier bridge arms, a balancing inductor is used at the output end of the rectifier bridge arm. However, using a balancing inductor increases the size and cost of the AC-DC charging module.

[0004] Therefore, there is an urgent need for a new transformer design method to effectively reduce the size and cost of the charging system while achieving voltage stabilization and current equalization. Summary of the Invention

[0005] To address the above problems, this invention provides a transformer design method.

[0006] In a first aspect, the present invention provides a transformer design method, the transformer comprising at least one set of secondary windings disposed on the secondary side, each set of secondary windings comprising multiple secondary windings; the output terminal of each secondary winding in each set of secondary windings is connected to the input terminal of a corresponding power conversion unit; the method comprising: repeatedly performing the following steps until a preset condition is met: determining the difference in output voltage of any pair of secondary windings in each set of secondary windings based on the phase shift angle and number of turns of each secondary winding in each set of secondary windings; when the preset condition is not met, adjusting the phase shift angle of at least one secondary winding in the set of secondary windings; wherein, the preset condition is that the difference in output voltage of any pair of secondary windings in the set of secondary windings is less than or equal to a preset threshold; wherein, the phase shift angle when the preset condition is met is the final phase shift angle of the secondary winding; the number of turns corresponding to the final phase shift angle is the final number of turns of the secondary winding.

[0007] In other optional embodiments, determining the difference in output voltage between any pair of secondary windings in each secondary winding set based on the phase shift angle and number of turns of each secondary winding in each secondary winding set includes: determining the theoretical number of turns of each secondary winding based on transformer parameters and the phase shift angle of each secondary winding; rounding the theoretical number of turns of each secondary winding to obtain the actual number of turns of each secondary winding; calculating the output voltage of each secondary winding based on the transformer parameters and the actual number of turns of each secondary winding; and determining the difference in output voltage between any pair of secondary windings based on the output voltage of each secondary winding.

[0008] In other optional embodiments, adjusting the phase shift angle of at least one secondary winding in each secondary winding set includes: adjusting the phase shift angle of the i-th secondary winding in the secondary winding set according to a first preset interval angle, where i is greater than or equal to 1; if the number of times the phase shift angle of the i-th secondary winding is adjusted according to the first preset interval angle is greater than a preset number, and the preset condition is still not met, adjusting the phase shift angle of the (i+1)-th secondary winding in the secondary winding set according to the first preset interval angle.

[0009] In other optional embodiments, the method further includes: if the number of times the phase shift angle of each secondary winding in the secondary winding set is adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, then the phase shift angle of all secondary windings in the secondary winding set is adjusted according to the second preset interval angle, and the step of adjusting the phase shift angle of at least one secondary winding in each secondary winding set is repeated; wherein the second preset interval angle is greater than the first preset interval angle.

[0010] In other optional embodiments, each secondary winding set includes N winding pairs, each winding pair includes a first secondary winding and a second secondary winding, and the phase shift angle difference between the first secondary winding and the second secondary winding is 30°; each power conversion unit includes two input terminals and one output terminal, and the output terminals of the first secondary winding and the second secondary winding are electrically connected to the two input terminals of the same power conversion unit respectively; where N is a positive integer; adjusting the phase shift angle of at least one secondary winding in each secondary winding set includes: determining that the difference in output voltage of j winding pairs is greater than a preset threshold, which does not meet the preset condition; adjusting the phase shift angle of the first secondary winding of each winding pair in the j winding pairs according to a first preset interval angle; if the number of times the phase shift angle of the first secondary winding of each winding pair in the j winding pairs is adjusted according to the first preset interval angle is greater than a preset number, and the preset condition is still not met, adjusting the phase shift angle of the second secondary winding of each winding pair in the j winding pairs according to the first preset interval angle; 1<=j<=N.

[0011] In other optional embodiments, the method further includes: if the number of times the phase shift angles of the first secondary winding and the second secondary winding of any winding pair in the j winding pairs are adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, then the phase shift angles of all secondary windings in the secondary winding set are adjusted according to the second preset interval angle, and the step of adjusting the phase shift angle of at least one secondary winding in each secondary winding set is repeated; wherein the second preset interval angle is greater than the first preset interval angle.

[0012] In other optional embodiments, the secondary winding set includes a first winding pair and a second winding pair. The first winding pair includes a first secondary winding and a second secondary winding. The output terminals of the first and second secondary windings are connected to the input terminal of the first power conversion unit corresponding to the first winding pair. The second winding pair includes a third secondary winding and a fourth secondary winding. The output terminals of the third and fourth secondary windings are connected to the input terminal of the second power conversion unit corresponding to the second winding pair. The phase of the output voltages of the first, third, second, and fourth secondary windings is shifted to the left or to the right by 15° sequentially. Adjusting the phase shift angle of at least one secondary winding in each secondary winding set includes: according to a first preset interval angle, for the first secondary winding in the first winding pair... The phase shift angle of the secondary winding is adjusted. If the number of times the phase shift angle of the first secondary winding is adjusted according to the first preset interval angle is greater than the preset number, and the difference between the output voltages of the first secondary winding and the second secondary winding still does not meet the preset condition, the phase shift angle of the second secondary winding in the set of first secondary windings is adjusted according to the first preset interval angle. The phase shift angle of the third secondary winding in the set of second secondary windings is adjusted according to the first preset interval angle. If the number of times the phase shift angle of the third secondary winding is adjusted according to the first preset interval angle is greater than the preset number, and the difference between the output voltages of the third secondary winding and the fourth secondary winding still does not meet the preset condition, the phase shift angle of the fourth secondary winding in the set of second secondary windings is adjusted according to the first preset interval angle.

[0013] In other optional embodiments, the method further includes: if the number of times the phase shift angles of the first secondary winding and the second secondary winding are adjusted according to the first preset interval angle is greater than a preset number, and the difference between the output voltages of the first secondary winding and the second secondary winding does not meet a preset condition; or if the number of times the phase shift angles of the third secondary winding and the fourth secondary winding are adjusted according to the first preset interval angle is greater than a preset number, and the difference between the output voltages of the third secondary winding and the fourth secondary winding does not meet a preset condition, then, according to the second preset interval angle, the phase shift angles of the first secondary winding, the second secondary winding, the third secondary winding, and the fourth secondary winding are all adjusted, and the step of adjusting the phase shift angle of at least one secondary winding in each set of secondary windings is repeated.

[0014] In other optional implementations, the preset threshold is 1.5V, the first preset interval angle is 0.1°, the second preset interval angle is 1°, and the preset number of times is 10.

[0015] The transformer design method provided by this invention involves repeatedly executing the following steps until a preset condition is met: determining the output voltage difference between any pair of secondary windings in each secondary winding set based on the phase shift angle and number of turns of each secondary winding; adjusting the phase shift angle of at least one secondary winding in the secondary winding set when the preset condition is not met; wherein the preset condition is that the output voltage difference between any pair of secondary windings in the secondary winding set is less than or equal to a preset threshold; wherein the phase shift angle when the preset condition is met is the final phase shift angle of the secondary winding; and the number of turns corresponding to the final phase shift angle is the final number of turns of the secondary winding. This invention, through continuous adjustment and iteration of the phase shift angle of the transformer's secondary windings, obtains the number of turns of the secondary windings that meets the preset condition, thereby solving the technical problem of excessive voltage difference caused by rounding the number of turns of the transformer's secondary windings, achieving input voltage regulation and current sharing of the rectifier bridge arm, and effectively reducing the size and cost of the charging system. Attached Figure Description

[0016] Figure 1 This invention provides a rectifier charging system based on a twelve-pulse transformer;

[0017] Figure 2 The present invention provides a rectifier charging system based on a 24-pulse transformer;

[0018] Figure 3 This invention provides an application scenario illustration;

[0019] Figure 4 A flowchart illustrating a transformer design method provided by the present invention;

[0020] Figure 5 Another rectifier charging system based on a multi-pulse transformer is provided by the present invention;

[0021] Figure 6 for Figure 5 A flowchart illustrating the design methodology for transformers;

[0022] Figure 7 A flowchart of phase shift angle adjustment for a novel 24-pulse transformer provided by the present invention;

[0023] Figure 8 This invention provides an iterative inner loop flowchart for adjusting the phase shift angle of a novel 24-pulse transformer.

[0024] Figure 9 A schematic diagram of the structure of a control device provided by the present invention;

[0025] Figure 10 This is a schematic diagram of the hardware structure of a control device provided by the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0027] Existing centralized high-power electric vehicle charging systems use isolation transformers to step down the 10kV grid voltage to a three-phase AC 380V voltage, which is then connected to n AC / DC (alternating current to direct current) charging modules, also known as power conversion units. Each AC / DC charging module consists of a power factor correction (PFC) pulse modulation (PWM) rectifier circuit and an isolated DC / DC (direct current to direct current) converter.

[0028] Another type of centralized high-power electric vehicle charging system is designed using a multi-pulse transformer-based rectifier charging system. In this system, a 10kV three-phase power grid is connected to the primary winding of the multi-pulse transformer, and multiple secondary windings of the transformer are connected to AC / DC charging modules. These AC / DC modules consist of uncontrolled rectification and non-isolated DC / DC converters. The multi-pulse transformer can be a twelve-pulse, twenty-four-pulse, thirty-six-pulse, or forty-eight-pulse transformer, etc.

[0029] Figure 1 This invention provides a rectifier charging system based on a twelve-pulse transformer, wherein every two secondary windings of the twelve-pulse transformer are input to a power conversion unit, such as... Figure 1 As shown, the first secondary winding 11 (Z1) and the second secondary winding 12 (Z3) on the secondary side of the transformer are input to the first power conversion unit 15, and the third secondary winding 13 (Z2) and the fourth secondary winding 14 (Z4) are input to the second power conversion unit 16. The first power conversion unit 15 includes a first input filter, a second input filter, a first rectifier bridge unit, a second rectifier bridge unit, a first DC-DC converter unit, and a first output filter. The first input filter, the second input filter, and the first output filter can further reduce harmonics. The first rectifier bridge unit consists of six diodes D... 11 D 12 D 13 D 14 D 15 D 16 Composition; the second rectifier bridge unit consists of six diodes D 21 D 22 D 23D 24 D 25 D 26 The system consists of two rectifier bridges. The output of Z1 is connected to the input of the first rectifier bridge unit via a first input filter, and the output of Z2 is connected to the input of the second rectifier bridge unit via a second input filter. The outputs of the first and second rectifier bridge units are then connected in parallel to form the first ports B1+ and B1-. The first ports B1+ and B1- are connected to the first power supply terminals V1+ and V1- via a first DC-DC converter unit. A first output filter can also be provided between the first DC-DC converter unit and the first power supply terminals V1+ and V1-.

[0030] In addition, Z2 and Z4 are input to the second power conversion unit 16, which provides the second power supply terminals V1+ and V1- for the device to be charged. The structure of the second power conversion unit 16 is similar to that of the first power conversion unit 15, and will not be described in detail here.

[0031] The phase shift angles of the first secondary winding 11 (Z1) and the second secondary winding 12 (Z3) differ by 30°; the phase shift angles of the third secondary winding 13 (Z2) and the fourth secondary winding 14 (Z4) differ by 30°.

[0032] Figure 2 Another rectifier charging system based on a 24-pulse transformer provided by the present invention, wherein every four secondary windings of the 24-pulse transformer are input to a power conversion unit, such as... Figure 2 As shown, the secondary windings Z1, Z3, Z2, and Z4 of the 24-pulse transformer are connected in parallel through their respective rectifier bridge units to form ports B1+ and B1-, and then connected to the power supply terminals V1+ and V1- through the first DC-DC conversion unit.

[0033] Similarly, a power conversion unit is input to every six secondary windings of a 36-pulse transformer, and a power conversion unit is input to every eight secondary windings of a 48-pulse transformer. The rectifier charging system based on either a 36-pulse or 48-pulse transformer has a structure similar to... Figure 2 The rectifier charging system shown is similar and will not be described in detail here.

[0034] However, in the above-mentioned rectifier charging system based on multi-pulse transformer, due to the influence of the rounding of the number of turns of the transformer winding, the output voltage of the secondary winding is not equal and the difference is large. This will cause uneven current flowing into the rectifier bridge arm. Uneven current will increase the current stress of the diode, and the device must have sufficient margin. This is not conducive to the selection of rectifier bridge and the selection of capacitor ripple current.

[0035] To address the aforementioned problems, the technical concept of this invention lies in obtaining the number of turns of the secondary winding when the output voltage difference between the secondary winding pairs is less than a preset threshold by continuously adjusting and iterating the phase shift angle of the secondary winding of the transformer. The number of turns of the secondary winding of the transformer is then adjusted according to the determined number of turns, thereby achieving voltage stabilization and current sharing. This eliminates the need for an external balancing reactor, reducing the size and cost of the charging system.

[0036] Figure 3 This is a schematic diagram of an application scenario provided by the present invention, such as... Figure 3 As shown, one application scenario provided by the present invention includes a transformer 1 and a control device 2, wherein the transformer 1 can be... Figure 1 or Figure 2 The multi-pulse transformer shown can also be other transformers; the control device 2 is used to execute the design methods of the following embodiments to determine the number of secondary turns of transformer 1.

[0037] This invention provides a method for designing a transformer. Figure 4 This is a flowchart illustrating a transformer design method provided by the present invention.

[0038] It should be noted that the transformer in this embodiment includes at least one set of secondary windings disposed on the secondary side, and each set of secondary windings includes multiple secondary windings; the output terminal of each secondary winding in each set of secondary windings is connected to the input terminal of the corresponding power conversion unit.

[0039] For example, a transformer can be Figure 1 The twelve-pulse transformer shown has two secondary windings in each set, such as Z1 and Z3, and the output terminals of Z1 and Z3 are connected to the input terminals of the corresponding power conversion units; the transformer can also be... Figure 2 The 24-pulse transformer shown has four secondary windings in each secondary winding set, such as Z1, Z3, Z2, and Z4, and the output terminals of Z1, Z3, Z2, and Z4 are connected to the input terminals of the corresponding power conversion units. Figure 1 In this case, secondary windings Z1 and Z3 form one set of secondary windings; secondary windings Z2 and Z4 form another set of secondary windings.

[0040] like Figure 4 As shown, the design method for this transformer includes:

[0041] Step 101: Determine the difference in output voltage between any pair of secondary windings in each secondary winding set based on the phase shift angle and number of turns of each secondary winding in each secondary winding set.

[0042] For example, regarding Figure 1The twelve-pulse transformer shown can determine the output voltage of Z1 based on the phase shift angle and number of turns of Z1 in one of the secondary winding sets. Then, it can determine the output voltage of Z3 based on the phase shift angle and number of turns of Z3 in the same secondary winding set, thereby determining the difference between the output voltages of Z1 and Z3 in the same secondary winding set. Similarly, it can determine the output voltage of Z2 based on the phase shift angle and number of turns of Z2 in another secondary winding set. Then, it can determine the output voltage of Z4 based on the phase shift angle and number of turns of Z4 in the same secondary winding set, thereby determining the difference between the output voltages of Z2 and Z4 in the same secondary winding set.

[0043] against Figure 2 Similarly, for the 24-pulse transformer shown, the output voltages of Z1, Z2, Z3, and Z4 in the secondary winding set can be determined based on the phase shift angle and number of turns of Z1, Z2, Z3, and Z4, respectively. Then, the difference in output voltage between any pair of secondary windings in the secondary winding set (i.e., between Z1-Z2, Z1-Z3, Z1-Z4, Z2-Z3, Z2-Z4, and Z3-Z4) can be determined. Figure 2 The secondary windings Z1, Z2, Z3, and Z4 form a set of secondary windings.

[0044] As an optional embodiment, step 101 includes: determining the theoretical number of turns of each secondary winding based on the transformer parameters and the phase shift angle of each secondary winding; rounding the theoretical number of turns of each secondary winding to obtain the actual number of turns of each secondary winding; calculating the output voltage of each secondary winding based on the transformer parameters and the actual number of turns of each secondary winding; and determining the difference in output voltage between any pair of secondary windings based on the output voltage of each secondary winding.

[0045] Specifically, the number of primary turns of the transformer can be selected based on predetermined transformer parameters (such as transformer size, input voltage, output voltage, current density, etc.). Then, the theoretical number of turns of the secondary winding can be calculated based on the transformer parameters, the number of primary turns, and the phase shift angle of the secondary winding, for example, 24.3 turns. However, considering that there will be no decimal number of turns in reality, the theoretical number of turns will be rounded to obtain the actual number of turns, for example, 24 turns. Then, the actual output voltage of the secondary winding can be calculated based on the transformer parameters and the actual number of turns of the secondary winding. Finally, the difference in output voltage between any pair of secondary windings in this set of secondary windings can be determined.

[0046] Step 102: Determine whether the preset conditions are met.

[0047] The preset condition is that the difference in output voltage between any pair of secondary windings in the set of secondary windings is less than or equal to a preset threshold.

[0048] If the preset conditions are met, proceed to step 104 and end; otherwise, proceed to step 103.

[0049] Specifically, those skilled in the art can set different preset thresholds according to different application scenarios. For example, for... Figure 1 For multi-pulse transformers, the following requirements apply to any set of secondary windings:

[0050] (1) Output voltage error of a single secondary winding Vo ± 5%;

[0051] (2) The output voltage difference between secondary windings with a phase shift angle difference of 30° is <1.5V;

[0052] (3) Short-circuit impedance 2%-10%.

[0053] For example, regarding Figure 2 For multi-pulse transformers, the following requirements apply to any set of secondary windings:

[0054] (1) Output voltage error of a single secondary winding Vo ± 5%;

[0055] (2) The output voltage difference between any two secondary windings is <1.5 volts;

[0056] (3) Short-circuit impedance 2%-10%.

[0057] Optionally, the preset threshold is selected as 1.5V, meaning the difference in output voltage between any pair of secondary windings in the secondary winding set must be less than 1.5V. Specifically, the difference in output voltage between the secondary windings connected to the same charging module (power conversion unit) is less than 1.5V, for example... Figure 1 The output voltage difference between the first secondary winding 11 and the second secondary winding 12 is less than 1.5V, and the output voltage difference between the third secondary winding 13 and the fourth secondary winding 14 is less than 1.5V; for example... Figure 2 The difference in output voltage between any pair of secondary windings is less than 1.5V.

[0058] Step 103: Adjust the phase shift angle of at least one secondary winding in the secondary winding set. Then repeat steps 101 and 102 until the preset conditions are met.

[0059] For example, regarding Figure 1 The twelve-pulse transformer shown can adjust the phase shift angle of Z1 or Z3. Then, based on the adjusted phase shift angle, the difference between the output voltages of Z1 and Z3 is calculated. If the difference between the output voltages of Z1 and Z3 meets the preset condition, step 104 is executed. If not, the phase shift angle of Z1 or Z3 is adjusted again until the difference between the output voltages of Z1 and Z3 meets the preset condition.

[0060] against Figure 2 The twelve-pulse transformer shown can adjust the phase shift angle of any one of the secondary windings Z1, Z2, Z3, and Z4. Based on the adjusted phase shift angle, it calculates whether the difference in output voltage between any pair of secondary windings of Z1, Z2, Z3, and Z4 meets the preset condition. If it does, step 104 is executed. If it does not meet the condition, the phase shift angle of any one of Z1, Z2, Z3, and Z4 is adjusted again until the difference in output voltage between any pair of secondary windings of Z1, Z2, Z3, and Z4 meets the preset condition.

[0061] As an optional embodiment, step 103 includes: adjusting the phase shift angle of the i-th secondary winding in the secondary winding set according to the first preset interval angle, where i is greater than or equal to 1; if the number of times the phase shift angle of the i-th secondary winding is adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, adjusting the phase shift angle of the (i+1)-th secondary winding in the secondary winding set according to the first preset interval angle.

[0062] As an optional embodiment, the method further includes: if the number of times the phase shift angle of each secondary winding in the secondary winding set is adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, then the phase shift angle of all secondary windings in the secondary winding set is adjusted according to the second preset interval angle, and the step of adjusting the phase shift angle of at least one secondary winding in each secondary winding set is repeated; wherein the second preset interval angle is greater than the first preset interval angle.

[0063] Specifically, the phase shift angle of the i-th secondary winding in the secondary winding set can be finely adjusted, for example, by adjusting it at a first preset interval of 0.1°. After each adjustment, the difference in output voltage between any pair of secondary windings in the secondary winding set is calculated. If the preset condition is still not met, the phase shift angle of the i-th secondary winding can be adjusted by another 0.1°. If the condition is still not met after a preset number of adjustments (e.g., 10 times), the phase shift angle of the (i+1)-th secondary winding can be adjusted at a first preset interval. This process is repeated until all secondary windings in the secondary winding set have been adjusted a preset number of times and the preset condition is still not met. In this case, the phase shift angle of all secondary windings in the secondary winding set can be uniformly adjusted, for example, by adjusting it at a second preset interval of 1°.

[0064] When adjusting a single secondary winding, the first preset interval angle is relatively small, for example, 0.1 degrees. If the preset condition is still not met after approximately 10 adjustments, another secondary winding needs to be adjusted. If all secondary windings in the set are adjusted by 0.1 degrees and the preset condition is still not met after 10 adjustments, all secondary windings can be uniformly adjusted by 1 degree. The process of adjusting according to the first preset interval can be called the inner loop of the adjustment iteration, and the process of adjusting according to the second preset interval can be called the outer loop of the adjustment iteration. In this embodiment, the inner loop of the adjustment iteration is first entered to adjust the phase shift angle of the secondary winding; if the condition is not met, the outer loop of the adjustment iteration is then entered. This invention, by setting the inner and outer loops of the adjustment iteration, keeps the difference in phase shift angles of the secondary windings around a set value, for example... Figure 1 In order to ensure that the phase shift angle difference between the secondary windings Z1 and Z3 is maintained at around 30°, Figure 2 The difference in phase shift angle between the secondary windings Z1 and Z3 remains around 15°.

[0065] Optionally, the first preset interval angle is 0.1°, the second preset interval angle is 1°, and the preset number of times is 10.

[0066] The following is combined with Figure 1 The twelve-pulse transformer shown below will be described in detail for this embodiment:

[0067] (1) Select the number of primary turns of the twelve-pulse transformer based on the predetermined transformer parameters (transformer size, input voltage, output voltage, current density).

[0068] (2) Initialize the phase shift angles of secondary windings Z1 and Z3: Take the initial phase shift angle of Z1 as 0° and the initial phase shift angle of Z3 as 30° as an example.

[0069] (3) Determine the theoretical number of turns of the secondary windings Z1 and Z3 based on the transformer parameters, the phase shift angle of the initialized secondary windings Z1 and Z3, and the number of turns of the primary winding;

[0070] (4) Round the theoretical number of turns of secondary windings Z1 and Z3 to obtain the actual number of turns of secondary windings Z1 and Z3;

[0071] (5) Determine the output voltages of Z1 and Z3 based on the actual number of turns of the secondary windings Z1 and Z3;

[0072] (6) Determine whether the output voltage difference between Z1 and Z3 is less than or equal to 1.5V;

[0073] (7) If the output voltage difference between Z1 and Z3 is not less than or equal to 1.5V, then add 0.1 degrees to the initial value of the phase shift angle of Z1, and recalculate the corresponding theoretical number of turns - rounded down - actual number of turns for Z1 and Z3. Determine whether the voltage difference between Z1 and Z3 is less than or equal to 1.5V. If yes, end; if no, add another 0.1 degrees to the phase shift angle of Z1 and repeat the calculation. If after repeating 10 times (for example, Z1 = 0.1, 0.2, 0.3, ... 0.9, 1, Z3 = 30° output voltage difference), the voltage difference between Z1 and Z3 is still not less than or equal to 1.5V, then adjust the initial value of the phase shift angle of Z3 again. If the initial phase shift angle of Z1 and Z3 is increased by 1 degree after 10 different values ​​(e.g., when Z1 = 0.1, Z3 = 30.1, 30.2, 30.3, ..., 30.9, 31; when Z1 = 0.2, Z3 = 30.1, 30.2, 30.3, ..., 30.9, 31; when Z1 = 0.9, Z3 = 30.1, 30.2, 30.3, ..., 30.9, 31), and the condition is still not met, the initial phase shift angle of Z1 and Z3 is increased by 1 degree. If the preset condition is still not met, the initial phase shift angle of Z1 = 1 and Z3 = 31 is adjusted by 0.1 degree again until the preset condition is met.

[0074] Combination Figure 2 The 24-pulse transformer shown is similar to the 12-pulse transformer in its adjustment. First, it enters the inner loop of the adjustment iteration, adjusting Z1, Z2, Z3, and Z4 sequentially by 0.1 degrees. It then checks if the output voltage difference between any two secondary windings (Z1-Z2, Z1-Z3, Z1-Z4, Z2-Z3, Z2-Z4, Z3-Z4) is less than or equal to 1.5V. If, after 10 adjustments, the voltage difference still does not meet the 1.5V requirement, it enters the outer loop of the adjustment iteration, simultaneously adjusting the phase shift angle of Z1, Z2, Z3, and Z4 by 1°. Then, it re-enters the inner loop of the adjustment iteration until the preset condition is met. Similarly, this embodiment can be used to adjust 36-pulse transformers, 48-pulse transformers, etc.

[0075] Step 104: Determine the phase shift angle when the preset conditions are met, which is the final phase shift angle of the secondary winding; the number of turns corresponding to the final phase shift angle is the final number of turns of the secondary winding.

[0076] Specifically, once the preset conditions are met, the phase shift angle at this point can be determined as the final phase shift angle of the secondary winding, and the number of turns corresponding to the final phase shift angle is the final number of turns of the secondary winding. Then, the number of turns on the secondary side of the transformer can be determined based on the determined final number of turns.

[0077] The transformer design method provided in this invention involves repeatedly performing the following steps until a preset condition is met: determining the output voltage difference of any pair of secondary windings in each secondary winding set based on the phase shift angle and number of turns of each secondary winding in each secondary winding set; adjusting the phase shift angle of at least one secondary winding in the secondary winding set when the preset condition is not met; wherein, the preset condition is that the output voltage difference of any pair of secondary windings in the secondary winding set is less than or equal to a preset threshold; wherein, the phase shift angle when the preset condition is met is the final phase shift angle of the secondary winding; the number of turns corresponding to the final phase shift angle is the final number of turns of the secondary winding; that is, this invention obtains the number of turns of the secondary winding that meets the preset condition by continuously adjusting and iterating the phase shift angle of the transformer's secondary winding, thereby solving the technical problem of excessive voltage difference caused by rounding the number of turns of the transformer's secondary winding, realizing current stabilization and current sharing of the input rectifier bridge arm, and effectively reducing the size and cost of the charging system.

[0078] Figure 5 Another rectifier charging system based on a multi-pulse transformer is provided by the present invention. For example... Figure 5 As shown, the secondary winding set includes N winding pairs, each winding pair including a first secondary winding and a second secondary winding; the charging system also includes N AC-DC conversion units and N power supply terminals, where N is a positive integer greater than or equal to 2. It should be noted that... Figure 5 The figure only shows one set of secondary windings, but it actually includes the primary winding and multiple sets of secondary windings. The structures of the sets of secondary windings are basically the same. To simplify the structure, only one set of secondary windings is shown in the figure.

[0079] exist Figure 5 Of the N winding pairs shown, the first winding pair (corresponding to) Figure 5 The topmost winding pair includes the first secondary winding Z1 and the second secondary winding Z2, and the Nth winding pair (corresponding to...) Figure 5 The bottommost winding pair includes a first secondary winding Z(2N-1) and a second secondary winding Z(2N). N AC-DC conversion units correspond one-to-one with the N winding pairs. Each AC-DC conversion unit includes a first input terminal, a second input terminal, and an output terminal, wherein the first input terminal is connected to the corresponding first secondary winding, and the second input terminal is connected to the corresponding second secondary winding. For example... Figure 5As shown, AC-DC converter 1 is connected to the first winding pair. Specifically, the first input terminal of AC-DC converter 1 is electrically connected to the first secondary winding Z1, and the second input terminal is electrically connected to the second secondary winding Z2. AC-DC converter N is connected to the Nth winding pair. Specifically, the first input terminal of AC-DC converter N is connected to the first secondary winding Z(2N-1), and the second input terminal is connected to the second secondary winding Z(2N). N power supply terminals correspond one-to-one with the N AC-DC converter units, and each power supply terminal is connected to its corresponding output terminal. Figure 5 As shown, AC-DC conversion unit 1 corresponds to power supply terminal D1. Specifically, the output terminal of AC-DC conversion unit 1 is electrically connected to power supply terminal D1 or directly forms power supply terminal D1; AC-DC conversion unit N corresponds to power supply terminal DN. Specifically, the output terminal of AC-DC conversion unit N is electrically connected to power supply terminal DN or directly forms power supply terminal DN.

[0080] In the same winding pair, the phase shift angle difference between the first secondary winding and the second secondary winding is 30° (for example, the phase shift angle difference between the first secondary winding Z1 and the second secondary winding Z2 is 30°). In adjacent winding pairs, the phase shift angle difference between the first secondary windings is 360° / 12N, and the phase shift angle difference between the second secondary windings in adjacent winding pairs is 360° / 12N.

[0081] When N power supply terminals are simultaneously connected to the charging device, 12N pulse rectification charging is performed. This can be understood as the power supply device forming a 12N pulse rectification charging structure when all N power supply terminals are in operation.

[0082] The specific structure of the AC-DC conversion unit can be found in [reference]. Figure 1 The first power conversion unit 15 shown here will not be described in detail here.

[0083] Figure 6 for Figure 5 A flowchart illustrating the design methodology for transformers.

[0084] like Figure 6 As shown, the design method for this transformer includes:

[0085] Step 201: Based on the phase shift angle and number of turns of each secondary winding in each secondary winding set, determine the difference in output voltage between each winding pair in the N winding pairs of each secondary winding set.

[0086] Specifically, based on the phase shift angle and number of turns of the first and second secondary windings in each winding pair, the output voltage of the first and second secondary windings in each winding pair is calculated, and then the difference in output voltage of each winding pair is calculated.

[0087] Step 202: Determine that the difference in output voltage of the j winding pairs is greater than a preset threshold, which does not meet the preset condition.

[0088] Where 1 <= j <= N.

[0089] Specifically, after step 201, it can be determined whether the difference in output voltage of each of the N winding pairs meets the preset condition, that is, whether the difference in output voltage of each winding pair is less than or equal to the preset threshold. If it meets the condition, then step 206 is executed. If it does not meet the condition, that is, it is determined that the difference in output voltage of j winding pairs is greater than the preset threshold, then step 203 is executed.

[0090] Step 203: Adjust the phase shift angle of the first secondary winding of each of the j winding pairs according to the first preset interval angle.

[0091] Step 204: If the number of times the phase shift angle of the first secondary winding of each of the j winding pairs is adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, then the phase shift angle of the second secondary winding of each of the j winding pairs is adjusted according to the first preset interval angle.

[0092] Step 205: If the number of times the phase shift angle of the first secondary winding and the second secondary winding of any winding pair in the j winding pairs is adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, then according to the second preset interval angle, the phase shift angle of all secondary windings in the secondary winding set is adjusted, and the step of adjusting the phase shift angle of at least one secondary winding in each secondary winding set is repeated.

[0093] The second preset interval angle is greater than the first preset interval angle.

[0094] Step 206: Determine the phase shift angle when the preset conditions are met, which is the final phase shift angle of the secondary winding; the number of turns corresponding to the final phase shift angle is the final number of turns of the secondary winding.

[0095] Step 206 in this embodiment is similar to step 104 in the aforementioned embodiment, and will not be described in detail here.

[0096] In this embodiment, each secondary winding set of the transformer includes N winding pairs, and each winding pair includes a first secondary winding and a second secondary winding. The phase shift angle difference between the first secondary winding and the second secondary winding is 30°. Each power conversion unit includes two input terminals and one output terminal. The output terminals of the first secondary winding and the second secondary winding are electrically connected to the two input terminals of the same power conversion unit, respectively. N is a positive integer. Adjusting the phase shift angle of at least one secondary winding in each secondary winding set includes: determining that the difference in output voltage of j winding pairs is greater than a preset threshold, which does not meet a preset condition; adjusting the phase shift angle of the first secondary winding of each winding pair in the j winding pairs according to a first preset interval angle; if the number of times the phase shift angle of the first secondary winding of each winding pair in the j winding pairs is adjusted according to the first preset interval angle is greater than a preset number, and the preset condition is still not met, adjusting the phase shift angle of the second secondary winding of each winding pair in the j winding pairs according to the first preset interval angle; 1 <= j <= N.

[0097] Specifically, in this transformer, the transformer can only achieve stable current sharing and normal operation when the difference in output voltage between each of the N winding pairs on the secondary side is less than or equal to a preset threshold. Therefore, if the output voltage difference of at least one winding pair does not meet the preset condition, the phase shift angle of that winding pair needs to be adjusted. In this embodiment, the first secondary winding of the winding pair that does not meet the preset condition is first adjusted iteratively, that is, the phase shift angle is slightly changed, increasing by 0.1 degrees each time, to obtain the output voltage of the first and second secondary windings, and the voltage difference is compared to see if it is less than or equal to 1.5V. If it still does not meet the condition after a preset number of adjustments, the second secondary winding is adjusted by 0.1 degrees; and so on, j winding pairs are adjusted sequentially.

[0098] As an optional embodiment, the method further includes step 205: if the number of times the phase shift angles of the first secondary winding and the second secondary winding of any winding pair in the j winding pairs are adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, then the phase shift angles of all secondary windings in the secondary winding set are adjusted according to the second preset interval angle, and the step of adjusting the phase shift angle of at least one secondary winding in each secondary winding set is repeated; wherein, the second preset interval angle is greater than the first preset interval angle.

[0099] Specifically, if the first and second secondary windings of any one of the j winding pairs are adjusted by 0.1 degrees 10 times and the preset conditions are still not met, then each secondary winding of the N winding pairs is adjusted by 1 degree as a whole (i.e., entering the outer loop of adjustment iteration), and then adjusted by 0.1 degrees again until the preset conditions are met.

[0100] The windings with a phase shift angle difference of 30° have the lowest harmonic output voltage. Adjusting the inner loop of the iteration ensures that the same winding is centered, and the phase shift angle difference between the first secondary winding and the second secondary winding is kept at about 30°. Adjusting the outer loop of the iteration ensures that adjacent windings are centered, and the phase shift angle difference between the first secondary winding and the second secondary winding is kept at about 360° / 12N.

[0101] As an optional embodiment, the secondary winding set includes a first winding pair and a second winding pair. The first winding pair includes a first secondary winding and a second secondary winding. The output terminals of the first and second secondary windings are connected to the input terminal of the first power conversion unit corresponding to the first winding pair. The second winding pair includes a third secondary winding and a fourth secondary winding. The output terminals of the third and fourth secondary windings are connected to the input terminal of the second power conversion unit corresponding to the second winding pair. The phase of the output voltages of the first, third, second, and fourth secondary windings is shifted to the left or to the right by 15° sequentially. This optional embodiment actually corresponds to... Figure 6 When N equals 2, the rectifier charging system is a 24-pulse rectifier charging system.

[0102] The adjustment of the phase shift angle of at least one secondary winding in each secondary winding set includes: adjusting the phase shift angle of the first secondary winding in the first winding pair according to a first preset interval angle; if the number of times the phase shift angle of the first secondary winding is adjusted according to the first preset interval angle is greater than a preset number, and the difference between the output voltages of the first secondary winding and the second secondary winding still does not meet the preset condition, adjusting the phase shift angle of the second secondary winding in the first secondary winding set according to the first preset interval angle; adjusting the phase shift angle of the third secondary winding in the second secondary winding set according to the first preset interval angle; if the number of times the phase shift angle of the third secondary winding is adjusted according to the first preset interval angle is greater than a preset number, and the difference between the output voltages of the third secondary winding and the fourth secondary winding still does not meet the preset condition, adjusting the phase shift angle of the fourth secondary winding in the second secondary winding set according to the first preset interval angle.

[0103] As an optional embodiment, the method further includes: if the number of times the phase shift angles of the first secondary winding and the second secondary winding are adjusted according to the first preset interval angle is greater than a preset number, and the difference between the output voltages of the first secondary winding and the second secondary winding does not meet a preset condition; or if the number of times the phase shift angles of the third secondary winding and the fourth secondary winding are adjusted according to the first preset interval angle is greater than a preset number, and the difference between the output voltages of the third secondary winding and the fourth secondary winding does not meet a preset condition, then, according to the second preset interval angle, the phase shift angles of the first secondary winding, the second secondary winding, the third secondary winding, and the fourth secondary winding are all adjusted, and the step of adjusting the phase shift angle of at least one secondary winding in each set of secondary windings is repeated.

[0104] Specifically, this embodiment defines a novel 24-pulse transformer, the structure of which is similar to... Figure 1 Similar to the twelve-pulse transformer shown, the difference lies in that the output voltages of Z1 and Z3 in the twelve-pulse transformer differ by 30 degrees, and it is only necessary to ensure that the difference between the output voltages of Z1 and Z3 meets a preset condition. The secondary windings Z1 and Z3 and secondary windings Z2 and Z4 belong to different sets of secondary windings. In contrast, the output voltages of the secondary windings Z1, Z2, Z3, and Z4 in the new twenty-four-pulse transformer differ by 15 degrees sequentially, and the secondary windings Z1, Z2, Z3, and Z4 need to operate simultaneously, belonging to the same set of secondary windings.

[0105] Figure 7 This invention provides a flowchart of the phase shift angle adjustment process for a novel 24-pulse transformer. Figure 8 This invention provides an iterative inner loop flowchart for adjusting the phase shift angle of a novel 24-pulse transformer. The following is in conjunction with... Figure 7 , Figure 8 The embodiments of the present invention will be described in detail below.

[0106] (1) Determine the number of primary turns of the transformer based on the predetermined transformer parameters (transformer size, input voltage, output voltage, current density).

[0107] (2) Initialize the corresponding phase shift angles Φ1, Φ2, Φ3, and Φ4 of Z1, Z2, Z3, and Z4 as follows: Φ1 = α°, then Φ2 = Φ1 + 15°, Φ3 = Φ1 + 30°, Φ4 = Φ1 + 45°

[0108] (3) Round the number of turns of secondary windings Z1 and Z3 to the nearest integer, and round the number of turns of secondary windings Z2 and Z4 to the nearest integer.

[0109] Specifically, based on the transformer parameters, the corresponding phase shift angles Φ1, Φ2, Φ3, and Φ4 of Z1, Z2, Z3, and Z4, and the number of primary turns, the theoretical number of turns of Z1, Z2, Z3, and Z4 is determined; then the theoretical number of turns of Z1, Z2, Z3, and Z4 is rounded down.

[0110] (4) Determine the output voltages of secondary windings Z1 and Z3, and the output voltages of secondary windings Z2 and Z4;

[0111] (5) Calculate the voltage difference ΔV1 between secondary windings Z1 and Z3, and the voltage difference ΔV2 between secondary windings Z2 and Z4;

[0112] (6) Determine whether ΔV1 is less than or equal to 1.5 and whether ΔV2 is less than or equal to 1.5;

[0113] (7) If satisfied, end the adjustment; if not satisfied, determine whether the adjustment times n1, n2, n3, and n4 corresponding to Z1, Z2, Z3, and Z4 are greater than the preset number (e.g., 10 times);

[0114] (8) If the number of iterations is less than the preset number, enter the inner loop of the adjustment iteration; if the number of iterations is greater than the preset number, enter the outer loop of the adjustment iteration, i.e., Φ1=Φ1+1°, then Φ2=Φ2+1°, Φ3=Φ3+1°, Φ4=Φ4+1°, and n1, n2, n3, and n4 are returned to 0.

[0115] For the new 24-pulse transformer, its adjustment iteration inner loop is as follows: Figure 8As shown, firstly, Z1 in the first winding pair is adjusted by 0.1 degrees, and n1 = 1, n3 = 0 is recorded. Then, with Z1 adjusted once, Z3 is adjusted. First, it is determined whether n3 is less than 10 (preset number of times). If it is less than 10, then n3 + 1, and Z3 is adjusted by n3 * 0.1 degrees accordingly. Then, the voltage difference ΔV1 between Z1 and Z3 is calculated, and it is determined whether ΔV1 is less than or equal to 1.5 (preset threshold). If not, it is returned to re-determine whether n3 is less than 10. When n3 is not less than 10, it means that the calculation of ΔV1 for Z3 = 30.1, 30.2, ..., 31 when Z1 = 0.1 has been completed. At this time, it is necessary to judge... If n1 is less than 10, then n1+1 and n3 returns to 0; at this point, the calculation loop (Z1=0.2, Z3=30.1, 30.2, ..., 31) begins; if n1 is greater than 10, it means that even after Z1 and Z3 have each completed 10 adjustments, the preset conditions are still not met. At this point, the inner loop of the iteration ends, and the outer loop of the iteration needs to be entered for adjustment (that is, the phase shift angles corresponding to Z1, Z2, Z3, and Z4 are all increased by 1 degree from the initial angle); if the preset conditions are met within 10 adjustments of Z1 or Z3, the phase shift angles of Z2 and Z4 of the second winding pair can continue to be adjusted. The adjustment process is similar to that of the first winding pair and will not be described in detail here.

[0116] And, through Figure 8 It can be seen that in the new 24-pulse transformer, if the preset conditions are still not met after adjusting the inner loop of the first winding pair or the second winding pair, Z1, Z2, Z3 and Z4 need to be adjusted by 1 degree at the same time, that is, enter the outer loop of the iteration.

[0117] Furthermore, in the transformer defined in this embodiment, it is only necessary to determine whether the output voltage between the first winding pairs Z1 and Z3, and the output voltage between the second winding pairs Z2 and Z4, meet the preset conditions. Compared to... Figure 2 In the 24-pulse transformer shown, it is necessary to determine the output voltage difference between Z1-Z2, Z1-Z3, Z1-Z4, Z2-Z3, Z2-Z4, and Z3-Z4. The transformer specified in this embodiment improves the adjustment efficiency of the phase shift angle.

[0118] The transformer design method provided in this embodiment of the invention includes N winding pairs in each secondary winding set, and each winding pair includes a first secondary winding and a second secondary winding. The phase shift angle difference between the first secondary winding and the second secondary winding is 30°. Each power conversion unit includes two input terminals and one output terminal. The output terminals of the first secondary winding and the second secondary winding are electrically connected to the two input terminals of the same power conversion unit, respectively. N is a positive integer. If the difference in output voltage of j winding pairs is greater than a preset threshold, and a preset condition is not met, the phase shift angle of the first secondary winding of each winding pair in the j winding pairs is adjusted according to a first preset interval angle. If the number of times the phase shift angle of the first secondary winding of each winding pair in the j winding pairs is adjusted according to the first preset interval angle is greater than a preset number, and the preset condition is still not met, the phase shift angle of the second secondary winding of each winding pair in the j winding pairs is adjusted according to the first preset interval angle. 1 <= j <= N. This embodiment improves the efficiency of adjusting the phase shift angle of the secondary windings.

[0119] Secondly, an example of the present invention provides a control device. Figure 9 This is a schematic diagram of a control device provided by the present invention. The control device is used in the design of a transformer. The transformer includes at least one set of secondary windings disposed on the secondary side, and each set of secondary windings includes multiple secondary windings. The output terminal of each secondary winding in each set of secondary windings is connected to the input terminal of a corresponding power conversion unit, such as... Figure 9 As shown, the control device includes:

[0120] The determining module 10 is used to determine the difference in output voltage between any pair of secondary windings in each secondary winding set based on the phase shift angle and number of turns of each secondary winding in each secondary winding set; the adjusting module 20 is used to adjust the phase shift angle of at least one secondary winding in the secondary winding set when the preset condition is not met; wherein, the preset condition is that the difference in output voltage between any pair of secondary windings in the secondary winding set is less than or equal to a preset threshold; wherein, the phase shift angle when the preset condition is met is the final phase shift angle of the secondary winding; and the number of turns corresponding to the final phase shift angle is the final number of turns of the secondary winding.

[0121] In other optional embodiments, the determining module 10 is specifically used to: determine the theoretical number of turns of each secondary winding based on the transformer parameters and the phase shift angle of each secondary winding; round down the theoretical number of turns of each secondary winding to obtain the actual number of turns of each secondary winding; calculate the output voltage of each secondary winding based on the transformer parameters and the actual number of turns of each secondary winding; and determine the difference in output voltage between any pair of secondary windings based on the output voltage of each secondary winding.

[0122] In other optional embodiments, the adjustment module 20 is specifically used to: adjust the phase shift angle of the i-th secondary winding in the secondary winding set according to the first preset interval angle, where i is greater than or equal to 1; if the number of times the phase shift angle of the i-th secondary winding is adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, adjust the phase shift angle of the (i+1)-th secondary winding in the secondary winding set according to the first preset interval angle.

[0123] In other optional embodiments, the adjustment module 20 is further configured to: if the number of times the phase shift angle of each secondary winding in the secondary winding set is adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, adjust the phase shift angle of all secondary windings in the secondary winding set according to the second preset interval angle, and repeat the step of adjusting the phase shift angle of at least one secondary winding in each secondary winding set; wherein the second preset interval angle is greater than the first preset interval angle.

[0124] In other optional embodiments, each secondary winding set includes N winding pairs, each winding pair includes a first secondary winding and a second secondary winding, and the phase shift angle difference between the first secondary winding and the second secondary winding is 30°; each power conversion unit includes two input terminals and one output terminal, and the output terminals of the first secondary winding and the second secondary winding are electrically connected to the two input terminals of the same power conversion unit respectively; where N is a positive integer; the adjustment module 20 is used to: determine that the difference in output voltage of j winding pairs is greater than a preset threshold, and does not meet the preset condition; adjust the phase shift angle of the first secondary winding of each winding pair in the j winding pairs according to a first preset interval angle; if the number of times the phase shift angle of the first secondary winding of each winding pair in the j winding pairs is adjusted according to the first preset interval angle is greater than a preset number, and the preset condition is still not met, adjust the phase shift angle of the second secondary winding of each winding pair in the j winding pairs according to the first preset interval angle; 1<=j<=N.

[0125] In other optional embodiments, the adjustment module 20 is further configured to: if the number of times the phase shift angles of the first secondary winding and the second secondary winding of any winding pair in the j winding pairs are adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, then, according to the second preset interval angle, the phase shift angles of all secondary windings in the secondary winding set are adjusted, and the step of adjusting the phase shift angle of at least one secondary winding in each secondary winding set is repeated; wherein, the second preset interval angle is greater than the first preset interval angle.

[0126] In other optional embodiments, the secondary winding set includes a first winding pair and a second winding pair. The first winding pair includes a first secondary winding and a second secondary winding. The output terminals of the first and second secondary windings are connected to the input terminal of the first power conversion unit corresponding to the first winding pair. The second winding pair includes a third secondary winding and a fourth secondary winding. The output terminals of the third and fourth secondary windings are connected to the input terminal of the second power conversion unit corresponding to the second winding pair. The phase of the output voltages of the first, third, second, and fourth secondary windings is shifted to the left or to the right by 15° sequentially. The adjustment module 20 is specifically used to: adjust the phase shift angle of the first secondary winding in the first winding pair according to a first preset interval angle. Adjustments are made as follows: If the number of times the phase shift angle of the first secondary winding is adjusted according to the first preset interval angle is greater than a preset number, and the difference between the output voltages of the first secondary winding and the second secondary winding still does not meet the preset condition, the phase shift angle of the second secondary winding in the set of first secondary windings is adjusted according to the first preset interval angle; the phase shift angle of the third secondary winding in the set of second secondary windings is adjusted according to the first preset interval angle; if the number of times the phase shift angle of the third secondary winding is adjusted according to the first preset interval angle is greater than a preset number, and the difference between the output voltages of the third secondary winding and the fourth secondary winding still does not meet the preset condition, the phase shift angle of the fourth secondary winding in the set of second secondary windings is adjusted according to the first preset interval angle.

[0127] In other optional embodiments, the adjustment module 20 is further configured to: if the number of times the phase shift angles of the first secondary winding and the second secondary winding are adjusted according to the first preset interval angle is greater than the preset number, and the difference between the output voltages of the first secondary winding and the second secondary winding does not meet the preset condition; or if the number of times the phase shift angles of the third secondary winding and the fourth secondary winding are adjusted according to the first preset interval angle is greater than the preset number, and the difference between the output voltages of the third secondary winding and the fourth secondary winding does not meet the preset condition, adjust the phase shift angles of the first secondary winding, the second secondary winding, the third secondary winding and the fourth secondary winding according to the second preset interval angle, and repeat the step of adjusting the phase shift angle of at least one secondary winding in each set of secondary windings.

[0128] In other optional implementations, the preset threshold is 1.5V, the first preset interval angle is 0.1°, the second preset interval angle is 1°, and the preset number of times is 10.

[0129] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process and corresponding beneficial effects of the control device described above can be referred to the corresponding process in the aforementioned method examples, and will not be repeated here.

[0130] The present invention also provides a control device. Figure 10 A schematic diagram of the hardware structure of a control device provided by the present invention is shown below. Figure 10 As shown, it includes:

[0131] At least one processor 1001 and memory 1002.

[0132] In the specific implementation process, at least one processor 1001 executes the computer execution instructions stored in the memory 1002, causing at least one processor 1001 to execute the above transformer design method, wherein the processor 1001 and the memory 1002 are connected through the bus 1003.

[0133] The specific implementation process of processor 1001 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0134] In the above Figure 10 In the illustrated embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0135] The memory may include high-speed RAM, and may also include non-volatile storage (NVM), such as at least one disk storage.

[0136] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0137] The present invention also provides a transformer system, which may be referred to. Figure 3 As shown, the device includes a transformer and the control equipment described above; wherein the transformer includes at least one set of secondary windings disposed on the secondary side, and each set of secondary windings includes multiple secondary windings; the output terminal of each secondary winding in each set of secondary windings is connected to the input terminal of the corresponding power conversion unit.

[0138] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process and corresponding beneficial effects of the transformer system described above can be found in the corresponding process in the aforementioned method examples, and will not be repeated here.

[0139] The present invention also provides a readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described transformer design method.

[0140] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0141] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0142] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for designing a transformer, characterized in that, The transformer includes at least one set of secondary windings disposed on the secondary side, each set of secondary windings including multiple secondary windings; the output terminal of each secondary winding in each set of secondary windings is electrically connected to at least one input terminal of a corresponding power conversion unit, each power conversion unit further including an output terminal; the method includes: Repeat the following steps until a preset condition is met: determine the difference in output voltage between any pair of secondary windings in each secondary winding set based on the phase shift angle and number of turns of each secondary winding in each secondary winding set; if the preset condition is not met, adjust the phase shift angle of at least one secondary winding in the secondary winding set; wherein, the preset condition is that the difference in output voltage between any pair of secondary windings in the secondary winding set is less than or equal to a preset threshold. Wherein, the phase shift angle when the preset condition is met is the final phase shift angle of the secondary winding; the number of turns corresponding to the final phase shift angle is the final number of turns of the secondary winding; Adjusting the phase shift angle of at least one secondary winding in each set of secondary windings includes: Based on the first preset interval angle, the phase shift angle of the i-th secondary winding in the secondary winding set is adjusted, where i is greater than or equal to 1; If the number of times the phase shift angle of the i-th secondary winding is adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, then the phase shift angle of the (i+1)-th secondary winding in the set of secondary windings is adjusted according to the first preset interval angle.

2. The method according to claim 1, characterized in that, The step of determining the output voltage difference between any pair of secondary windings in each secondary winding set based on the phase shift angle and number of turns of each secondary winding in each secondary winding set includes: The theoretical number of turns for each secondary winding is determined based on the transformer parameters and the phase shift angle of each secondary winding. The theoretical number of turns for each secondary winding is rounded down to obtain the actual number of turns for each secondary winding. Calculate the output voltage of each secondary winding based on the transformer parameters and the actual number of turns of each secondary winding. The difference in output voltage between any pair of secondary windings is determined based on the output voltage of each secondary winding.

3. The method according to claim 1, characterized in that, The method further includes: if the number of times the phase shift angle of each secondary winding in the secondary winding set is adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, then the phase shift angle of all secondary windings in the secondary winding set is adjusted according to the second preset interval angle, and the step of adjusting the phase shift angle of at least one secondary winding in each secondary winding set is repeated; wherein the second preset interval angle is greater than the first preset interval angle.

4. The method according to claim 1 or 2, characterized in that, Each secondary winding set includes N winding pairs, and each winding pair includes a first secondary winding and a second secondary winding. The phase shift angle difference between the first secondary winding and the second secondary winding is 30°. Each power conversion unit includes two input terminals. The output terminals of the first secondary winding and the second secondary winding are electrically connected to the two input terminals of the same power conversion unit, respectively. Where N is a positive integer; The adjustment of the phase shift angle of at least one secondary winding in each set of secondary windings includes: It is determined that the difference in output voltage of j winding pairs is greater than a preset threshold, and the preset condition is not met; According to the first preset interval angle, the phase shift angle of the first secondary winding of each of the j winding pairs is adjusted; If the number of times the phase shift angle of the first secondary winding of each of the j winding pairs is adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, then the phase shift angle of the second secondary winding of each of the j winding pairs is adjusted according to the first preset interval angle; 1≤j≤N.

5. The method according to claim 4, characterized in that, The method further includes: if the number of times the phase shift angles of the first secondary winding and the second secondary winding of any winding pair in the j winding pairs are adjusted according to the first preset interval angle is greater than the preset number, and the preset condition is still not met, then the phase shift angles of all secondary windings in the secondary winding set are adjusted according to the second preset interval angle, and the step of adjusting the phase shift angle of at least one secondary winding in each secondary winding set is repeated; wherein the second preset interval angle is greater than the first preset interval angle.

6. The method according to claim 5, characterized in that, The secondary winding set includes a first winding pair and a second winding pair. The first winding pair includes a first secondary winding and a second secondary winding. The output terminals of the first and second secondary windings are connected to the input terminal of the first power conversion unit corresponding to the first winding pair. The second winding pair includes a third secondary winding and a fourth secondary winding. The output terminals of the third and fourth secondary windings are connected to the input terminal of the second power conversion unit corresponding to the second winding pair. The phase of the output voltages of the first, third, second, and fourth secondary windings is shifted to the left or to the right by 15° sequentially. Adjusting the phase shift angle of at least one secondary winding in each secondary winding set includes: According to the first preset interval angle, the phase shift angle of the first secondary winding in the first winding pair is adjusted; If the number of times the phase shift angle of the first secondary winding is adjusted according to the first preset interval angle is greater than the preset number, and the difference between the output voltages of the first secondary winding and the second secondary winding still does not meet the preset condition, the phase shift angle of the second secondary winding in the set of first secondary windings is adjusted according to the first preset interval angle. Based on the first preset interval angle, the phase shift angle of the third secondary winding in the second secondary winding set is adjusted; If the number of times the phase shift angle of the third secondary winding is adjusted according to the first preset interval angle is greater than the preset number, and the difference between the output voltages of the third and fourth secondary windings still does not meet the preset condition, then the phase shift angle of the fourth secondary winding in the set of second secondary windings is adjusted according to the first preset interval angle.

7. The method according to claim 6, characterized in that, The method further includes: if the number of times the phase shift angle of the first secondary winding and the second secondary winding is adjusted according to the first preset interval angle is greater than the preset number, and the difference between the output voltages of the first secondary winding and the second secondary winding does not meet the preset condition; or if the number of times the phase shift angle of the third secondary winding and the fourth secondary winding is adjusted according to the first preset interval angle is greater than the preset number, and the difference between the output voltages of the third secondary winding and the fourth secondary winding does not meet the preset condition, then the phase shift angles of the first secondary winding, the second secondary winding, the third secondary winding and the fourth secondary winding are all adjusted according to the second preset interval angle, and the step of adjusting the phase shift angle of at least one secondary winding in each set of secondary windings is repeated.

8. The method according to any one of claims 3, 5-7, characterized in that, The preset threshold is 1.5V, the first preset interval angle is 0.1°, the second preset interval angle is 1°, and the preset number of times is 10.

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