Energy feedback high-capacity high-frequency transformer test power supply topology and control method

Abstract

The present application belongs to the technical field of power supply for large-capacity high-frequency transformer testing, and particularly relates to an energy feedback large-capacity high-frequency transformer testing power supply topology and control method, aiming to solve the problem of resource waste caused by large power consumption in the temperature field testing of large-capacity high-frequency transformers in the prior art. The present application comprises: a three-phase multi-winding transformer, including one primary three-phase winding and M+N secondary three-phase windings; M+N AC / AC modules corresponding to the secondary three-phase windings; a first resonant capacitor connected in series between the first AC / AC module and the high-voltage side of the large-capacity high-frequency transformer to be tested; a second resonant capacitor connected in series between the M+1th AC / AC module and the low-voltage side of the large-capacity high-frequency transformer to be tested; and a first bypass switch and a second bypass switch connected in parallel with the first resonant capacitor and the second resonant capacitor, respectively. The present application saves electric energy and occupies less resources, has a modular structure, a wide test voltage range, a low rated voltage of a single module, and strong reconfigurability.

Description

Technical Field

[0001] This invention belongs to the field of power supply technology for testing large-capacity high-frequency transformers, and specifically relates to a power supply topology and control method for testing large-capacity high-frequency transformers with energy feedback. Background Technology

[0002] Isolated DC / DC converters, as fundamental components of renewable energy integration and flexible AC / DC transmission equipment, achieve voltage level conversion and electrical isolation. The key component is the transformer. As my country gradually builds a new power system dominated by renewable energy, the scale of renewable energy integration and the demand for flexible AC / DC transmission are constantly increasing. This requires isolated DC / DC converters to have larger capacity and higher frequency isolation transformers to achieve greater transmission power and higher power density.

[0003] Because high-capacity high-frequency transformers have large capacities, their rated voltage exceeds the withstand voltage range of existing power semiconductor devices in order to maintain their rated current at a reasonable level, rendering traditional two-level converters unsuitable. Multilevel converters use low-voltage power semiconductor devices to achieve high-voltage, high-capacity power conversion. However, for modular multilevel converters, which currently have potential practical application value, their cost is high when the number of levels is large, and when operating at high-frequency square wave output on the AC side, it is difficult to balance the voltage of the submodule capacitors.

[0004] Most parameters of large-capacity high-frequency transformers can be measured quickly using specialized instruments. However, measuring parameters such as the temperature field distribution of large-capacity high-frequency transformers requires long-term operation under rated conditions to verify the rationality of the transformer's design. Traditional high-frequency transformer temperature rise testing involves connecting a load resistor to the load side of an isolated DC / DC converter to operate the large-capacity high-frequency transformer under rated conditions. However, this method consumes a large amount of electrical energy, resulting in resource waste. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies—namely, the high energy consumption and resource waste in existing power supply topologies for large-capacity high-frequency transformer temperature field testing, coupled with the high cost of modular multilevel converters (which have potential practical applications) and the difficulty in achieving voltage balancing of submodule capacitors when operating at high-frequency square wave output on the AC side—this invention provides an energy feedback power supply topology for testing large-capacity high-frequency transformers. The power supply topology includes:

[0006] The three-phase multi-winding transformer comprises a primary three-phase winding, M secondary three-phase windings corresponding to the AC / DC power units of the AC / AC modules on the high-voltage side of the large-capacity high-frequency transformer to be tested, and N secondary three-phase windings corresponding to the AC / DC power units of the AC / AC modules on the low-voltage side of the large-capacity high-frequency transformer to be tested, M≥N;

[0007] M+N AC / AC modules corresponding to the M secondary three-phase windings and the N secondary three-phase windings;

[0008] A first resonant capacitor is connected in series between the first output terminal of the first AC / AC module of the M AC / AC modules and the first input terminal of the high-voltage side of the large-capacity high-frequency transformer to be tested.

[0009] A second resonant capacitor is connected in series between the first output terminal of the first AC / AC module of the N AC / AC modules and the first input terminal of the low-voltage side of the large-capacity high-frequency transformer to be tested.

[0010] The first bypass switch is connected in parallel with the first resonant capacitor, and the second bypass switch is connected in parallel with the second resonant capacitor.

[0011] In some preferred embodiments, when the large-capacity high-frequency transformer to be tested needs to operate in a resonant mode, the first bypass switch and the second bypass switch are opened, and the first resonant capacitor and the second resonant capacitor resonate with the inductance in the primary and secondary circuits of the large-capacity high-frequency transformer to be tested, respectively, so that the large-capacity high-frequency transformer to be tested operates in a resonant mode.

[0012] In some preferred embodiments, when the large-capacity high-frequency transformer to be tested needs to operate in a phase-shift mode, the first bypass switch and the second bypass switch are closed, and the first resonant capacitor and the second resonant capacitor are bypassed, so that the large-capacity high-frequency transformer to be tested operates in a phase-shift mode.

[0013] In some preferred embodiments, the three AC terminals T P1 , T P2 and T P3 of the primary three-phase winding are connected to the A-phase, B-phase and C-phase of the three-phase AC power grid, respectively.

[0014] In some preferred embodiments, the three AC terminals T i,1 , T i,2 and T i,3 of the i-th secondary three-phase winding of the M secondary three-phase windings are connected to the three AC terminals T i,4 , T i,5 and T i,6 on the input side of the corresponding AC / AC module, respectively.

[0015] the jth secondary three-phase winding of the N secondary three-phase windings has three AC terminals T j,1 , T j,2 and T j,3 connected to the three AC terminals T j,4 , T j,5 and T j,6 of the input side of the corresponding AC / AC module respectively;

[0016] wherein 1≤i≤M and M+1≤j≤M+N.

[0017] In some preferred embodiments, the output side AC terminal T 1,11 of the first AC / AC module of the M+N AC / AC modules is connected to the terminal T r1,1 of the first resonant capacitor, the terminal T r1,2 of the first resonant capacitor is connected to the first input terminal P1 of the high voltage side of the large-capacity high-frequency transformer to be tested, the output side AC terminal T M,12 of the Mth AC / AC module is connected to the second input terminal P2 of the high voltage side of the large-capacity high-frequency transformer to be tested, the output side AC terminal T M+1,11 of the M+1th AC / AC module is connected to the terminal T r2,2 of the second resonant capacitor, the terminal T r2,1 of the second resonant capacitor is connected to the first input terminal S1 of the low voltage side of the large-capacity high-frequency transformer to be tested, the output side AC terminal T M+N,12 of the M+Nth AC / AC module is connected to the second input terminal S2 of the low voltage side of the large-capacity high-frequency transformer to be tested, the output side AC terminal T i,11 of the ith AC / AC module is connected to the output side AC terminal T i-1,12 of the (i-1)th AC / AC module, and the output side AC terminal T j,11 of the jth AC / AC module is connected to the output side AC terminal T j-1,12 of the (j-1)th AC / AC module.

[0018] In some preferred embodiments, the kth AC / AC module of the M+N AC / AC modules comprises an AC / DC power unit k, a DC / AC power unit k and a bypass switch SW k , wherein 1≤k≤M+N.

[0019] In another aspect of the present application, a control method for the energy feedback large-capacity high-frequency transformer test power supply topology is provided, based on the above-mentioned energy feedback large-capacity high-frequency transformer test power supply topology, the control method comprises:

[0020] Let U be the DC bus voltage of the AC / DC power unit of the k-th AC / AC module in the M+N AC / AC modules. dck And satisfy and Where 1≤k≤M+N, U N,H and U N,L These are the AC bypass switches SW1 to SW1 of the DC / AC power units of the M+N AC / AC modules. M+N When disconnected, test the high-voltage side rated voltage and low-voltage side rated voltage of the energy feedback high-capacity high-frequency transformer test power supply topology;

[0021] The high-voltage side voltage U of the large-capacity high-frequency transformer to be tested H Its scope is:

[0022]

[0023] Where, δ max,H and δ min,H Let δ be the maximum and minimum regulation coefficients of the DC bus voltage for AC / DC power units 1 to M in the M AC / AC modules, respectively, and let δ be the maximum and minimum regulation coefficients of the DC bus voltage for AC / DC power units 1 to M in the M AC / AC modules. min,H <1<δ max,H ;m SW This refers to the number of power units from AC / DC power unit 1 to AC / DC power unit M in M ​​AC / AC modules that are bypassed by the AC side bypass switch, where 1 ≤ m. SW ≤M-1;

[0024] The low-voltage side voltage U of the large-capacity high-frequency transformer to be tested L Its scope is:

[0025]

[0026] Where, δ max,L and δ min,L Let δ represent the maximum and minimum regulation coefficients of the DC bus voltage for AC / DC power units (M+1) to AC / DC power units (M+N) in N AC / AC modules, respectively, and let δ min,L <1<δ max,L ;n SW This refers to the number of power units in the N AC / AC modules, from AC / DC power units (M+1) to AC / DC power units (M+N), that are bypassed by the AC-side bypass switch, where 1 ≤ n. SW ≤N-1;

[0027] The maximum active power P of the large-capacity high-frequency transformer under test was tested using a power supply topology with energy feedback. max for:

[0028]

[0029] wherein P N is the rated power of the energy feedback large-capacity high-frequency transformer test power supply topology, δ H and δ L are the DC bus voltage regulation coefficients of the AC / DC power units 1-AC / DC power unit M in the M AC / AC modules and the DC bus voltage regulation coefficients of the AC / DC power units M+1-AC / DC power unit M+N in the N AC / AC modules, respectively.

[0030] In some preferred embodiments, when the large-capacity high-frequency transformer to be tested needs to operate in a resonant operating mode, the energy feedback large-capacity high-frequency transformer test power supply topology operating control process is as follows:

[0031] The first bypass switch and the second bypass switch are placed in an open state, the grid-side voltage of the primary winding of the three-phase multi-winding transformer is phase-locked by a controller of the energy feedback large-capacity high-frequency transformer test power supply topology, and the real-time phase of the grid voltage is obtained;

[0032] The DC bus voltage of the AC / DC power unit p (1≤p≤M-m SW ) is controlled by adopting outer loop DC bus voltage closed loop and inner loop AC side current closed loop, the active power of the AC / DC power unit q (M+1≤q≤M+N-n SW ) is controlled by adopting outer loop DC voltage closed loop and power feedforward and inner loop AC side current closed loop, and the DC voltage of the AC / DC power unit is stabilized, in order to facilitate the implementation of the energy feedback large-capacity high-frequency transformer test power supply topology, the rated electrical parameters of the AC / DC power units (M+1) to (M+N) are selected to be consistent, the rated electrical parameters of the DC / AC power units (M+1) to (M+N) are selected to be consistent, and the reference current given by the outer loop power feedforward of the AC / DC power unit q is as follows:

[0033]

[0034] wherein P ref,T is the operating power instruction of the large-capacity high-frequency transformer to be tested, γ is the operating efficiency of the AC / DC power unit q, ε is the operating efficiency of the DC / AC power unit q, U acL is the AC side rated voltage of the AC / DC power unit q.

[0035] The reference current generated by the outer loop DC voltage controller is as follows:

[0036]

[0037] wherein the voltage controller is:

[0038]

[0039] wherein k 1,q and k 2,q are proportional and integral coefficients, respectively;

[0040] The reference current of the AC / DC power unit q is:

[0041] I refq = I ref + ΔI refq

[0042] The AC / DC power unit (M-m SW +1)~AC / DC power unit M and the AC / DC power unit (M+N-n SW +1)~AC / DC power unit (M+N) are blocked, the bypass switches ~bypass switch SW M and the bypass switches ~bypass switch SW M+N are placed in the closed state, other bypass switches are placed in the open state, the DC / AC power unit (M-m SW +1)~DC / AC power unit M is blocked, the DC / AC power unit (M+N-n SW +1)~DC / AC power unit (M+N) is blocked, the DC / AC power unit 1~DC / AC power unit (M-m SW ), the large-capacity high-frequency transformer to be tested, and the DC / AC power unit (M+1)~DC / AC power unit (M+N-n SW ) constitute a resonant dual active bridge converter, the controller controls the AC side output of the DC / AC power unit which is not bypassed to be a square wave voltage, the AC side voltage frequency is the same as the rated frequency of the large-capacity high-frequency transformer to be tested, and the AC side output voltages of the DC / AC power unit 1~DC / AC power unit (M-m SW ) and the DC / AC power unit (M+1)~DC / AC power unit (M+N-n SW ) are in phase, so that the primary side and secondary side voltages of the large-capacity high-frequency transformer to be tested are square wave voltages, the controller issues a power instruction of the AC / DC power unit (M+1)~AC / DC power unit (M+N-n SW ) to make it feed power to the power grid or take power from the power grid, and adjusts the power instruction to make the large-capacity high-frequency transformer to be tested operate in a rated state.

[0043] In some preferred embodiments, when the large-capacity high-frequency transformer to be tested needs to operate in a phase-shifting operation mode, the energy feedback large-capacity high-frequency transformer test power supply topology operation control process is as follows:

[0044] The first bypass switch and the second bypass switch are placed in a closed state, the controller of the energy feedback large-capacity high-frequency transformer test power supply topology phase-locks the grid side voltage of the primary winding of the three-phase multi-winding transformer, and the real-time phase of the grid voltage is obtained;

[0045] The DC bus voltage of the DC / AC power unit t (1≤t≤M-m SW , M+1≤t≤M+N-n SW ) is controlled by adopting outer loop DC bus voltage closed loop and inner loop AC side current closed loop, the bypass switch ~ the bypass switch SW M and the bypass switch ~ the bypass switch SW M+N are placed in a closed state, other bypass switches are placed in an open state, the DC / AC power unit (M-m SW +1) ~ the DC / AC power unit M are locked, the DC / AC power unit (M+N-n SW +1) ~ the DC / AC power unit (M+N) are locked, the DC / AC power unit 1 ~ the DC / AC power unit (M-m SW ), the large-capacity high-frequency transformer to be tested and the DC / AC power unit (M+1) ~ the DC / AC power unit (M+N-n SW ) constitute a phase-shifting dual active bridge converter, the controller controls the AC side output of the DC / AC power unit which is not bypassed to be a square wave voltage, the frequency of the AC side voltage is the same as the rated frequency of the large-capacity high-frequency transformer to be tested, the AC side output voltages of the DC / AC power unit 1 ~ the DC / AC power unit (M-m SW ) are controlled to be in the same phase, the AC side output voltages of the DC / AC power unit (M+1) ~ the DC / AC power unit (M+N-n SW ) are controlled to be in the same phase, the phase of the AC side output voltage of the DC / AC power unit (M+1) ~ the DC / AC power unit (M+N-n SW ) is controlled, so that u s lags behind or leads u p , and the large-capacity high-frequency transformer to be tested operates in a rated capacity state, wherein u p is the sum of the AC output voltages of all DC / AC power units on the high-voltage side of the large-capacity high-frequency transformer to be tested, and u s is the sum of the AC output voltages of all DC / AC power units on the low-voltage side of the large-capacity high-frequency transformer to be tested.

[0046] The present application has the following advantages:

[0047] (1) The energy feedback large-capacity high-frequency transformer test power supply topology of the present application can realize energy feedback through a three-phase multi-winding transformer when measuring the temperature field parameters of a large-capacity high-frequency transformer to be tested, thereby saving a large amount of electric energy and greatly reducing resource consumption compared with traditional methods.

[0048] (2) The energy feedback large-capacity high-frequency transformer test power supply topology of the present application adopts a modular structure, has a wide test voltage range, low rated voltage of a single module, and strong reconfigurability. BRIEF DESCRIPTION OF DRAWINGS

[0049] Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments made with reference to the accompanying drawings:

[0050] Figure 1 is a structural schematic diagram of the energy feedback large-capacity high-frequency transformer test power supply topology of the present application;

[0051] Figure 2 is a structural schematic diagram of an AC / AC module of an embodiment of the energy feedback large-capacity high-frequency transformer test power supply topology;

[0052] Figure 3 is a DC voltage closed-loop and power feed-forward outer-loop control block diagram when the large-capacity high-frequency transformer to be tested operates in a resonant mode in an embodiment of the energy feedback large-capacity high-frequency transformer test power supply topology; SW

[0053] Figure 4 is a first simulation result when the large-capacity high-frequency transformer to be tested operates in a resonant mode in an embodiment of the energy feedback large-capacity high-frequency transformer test power supply topology;

[0054] Figure 5 is a second simulation result when the large-capacity high-frequency transformer to be tested operates in a resonant mode in an embodiment of the energy feedback large-capacity high-frequency transformer test power supply topology;

[0055] Figure 6 is a third simulation result when the large-capacity high-frequency transformer to be tested operates in a resonant mode in an embodiment of the energy feedback large-capacity high-frequency transformer test power supply topology;

[0056] Figure 7 is a fourth simulation result when the large-capacity high-frequency transformer to be tested operates in a resonant mode in an embodiment of the energy feedback large-capacity high-frequency transformer test power supply topology;

[0057] Figure 8 ​is the fifth simulation result of the to-be-tested large-capacity high-frequency transformer in the resonant mode of the energy feedback large-capacity high-frequency transformer test power supply topology of one embodiment;

[0058] Figure 9 is the first simulation result of the to-be-tested large-capacity high-frequency transformer in the phase-shift control mode of the energy feedback large-capacity high-frequency transformer test power supply topology of one embodiment;

[0059] Figure 10 is the second simulation result of the to-be-tested large-capacity high-frequency transformer in the phase-shift control mode of the energy feedback large-capacity high-frequency transformer test power supply topology of one embodiment;

[0060] Figure 11 is the third simulation result of the to-be-tested large-capacity high-frequency transformer in the phase-shift control mode of the energy feedback large-capacity high-frequency transformer test power supply topology of one embodiment;

[0061] Figure 12 is the fourth simulation result of the to-be-tested large-capacity high-frequency transformer in the phase-shift control mode of the energy feedback large-capacity high-frequency transformer test power supply topology of one embodiment;

[0062] Figure 13 is the fifth simulation result of the to-be-tested large-capacity high-frequency transformer in the phase-shift control mode of the energy feedback large-capacity high-frequency transformer test power supply topology of one embodiment. DETAILED DESCRIPTION

[0063] The application will be further described below in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, and not to limit the application. In addition, it should be noted that only the parts related to the application are shown in the drawings for ease of description.

[0064] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0065] The energy feedback large-capacity high-frequency transformer test power supply topology of the present application comprises:

[0066] The three-phase multi-winding transformer comprises one primary three-phase winding, M secondary three-phase windings corresponding to the AC / DC power units of the AC / AC modules on the high-voltage side of the to-be-tested large-capacity high-frequency transformer, and N secondary three-phase windings corresponding to the AC / DC power units of the AC / AC modules on the low-voltage side of the to-be-tested large-capacity high-frequency transformer, and M≥N;

[0067] M+N AC / AC modules, each corresponding one-to-one with the M secondary three-phase windings and the N secondary three-phase windings;

[0068] The first resonant capacitor is connected in series with the first output terminal of the M AC / AC modules and the first input terminal of the high-voltage side of the large-capacity high-frequency transformer under test.

[0069] The second resonant capacitor is connected in series with the first output terminal of the N AC / AC modules and the first input terminal of the low-voltage side of the large-capacity high-frequency transformer under test.

[0070] The first bypass switch is connected in parallel with the first resonant capacitor, and the second bypass switch is connected in parallel with the second resonant capacitor.

[0071] To more clearly explain the topology of the energy feedback high-capacity high-frequency transformer test power supply of this invention, the following will be combined with... Figure 1 The modules in the embodiments of the present invention will be described in detail below.

[0072] The energy feedback high-capacity high-frequency transformer test power supply topology of the first embodiment of the present invention includes a three-phase multi-winding transformer, M+N AC / AC modules (AC / AC module 1 to AC / AC module M+N), a first bypass switch, a second bypass switch, a first resonant capacitor, and a second resonant capacitor. Each module is described in detail below:

[0073] A three-phase multi-winding transformer includes one primary three-phase winding, M secondary three-phase windings corresponding one-to-one with the AC / DC power units of the AC / AC module on the high-voltage side of the large-capacity high-frequency transformer under test, and N secondary three-phase windings corresponding one-to-one with the AC / DC power units of the AC / AC module on the low-voltage side of the large-capacity high-frequency transformer under test, where M ≥ N.

[0074] The three AC terminals T of the primary three-phase winding P1 T P2 and T P3 Phases A, B, and C are respectively connected to a three-phase AC power grid;

[0075] The three AC terminals T of the i-th secondary three-phase winding in M ​​secondary three-phase windings i,1 T i,2 and T i,3 The three AC terminals T are respectively connected to the input side of the corresponding AC / AC module (the i-th of M AC / AC modules). i,4 T i,5 and T i,6 ;

[0076] The j-th secondary three-phase winding in N secondary windings has three AC terminals T. j,1 T j,2 and Tj,3 The three AC terminals T are respectively connected to the input side of the corresponding AC / AC module (the j-th of N AC / AC modules). j,4 T j,5 and T j,6 ;

[0077] Where 1≤i≤M, M+1≤j≤M+N.

[0078] The M secondary three-phase windings and N secondary three-phase windings of the three-phase multi-winding transformer provide three-phase AC voltage to the AC / DC power units in the corresponding AC / AC modules.

[0079] There are M+N AC / AC modules, each corresponding one-to-one with M secondary three-phase windings and N secondary three-phase windings. The output AC terminal T of the first AC / AC module... 1,11 Terminal T connected to the first resonant capacitor r1,1 Terminal T of the first resonant capacitor r1,2 Connect to the first input terminal P1 on the high-voltage side of the high-capacity high-frequency transformer under test, and the output AC terminal T of the Mth AC / AC module. M,12 Connect to the second input terminal P2 on the high-voltage side of the large-capacity high-frequency transformer under test, and the output AC terminal T of the (M+1)th AC / AC module. M+1,11 Terminal T connected to the second resonant capacitor r2,2 Terminal T of the second resonant capacitor r2,1 Connect to the first input terminal S1 on the low-voltage side of the high-frequency transformer under test, and the AC terminal T on the output side of the M+Nth AC / AC module. M+N,12 The second input terminal S2 is connected to the low-voltage side of the large-capacity high-frequency transformer under test, and the output AC terminal T of the i-th AC / AC module is connected to the AC terminal T of the i-th AC / AC module. i,11 Connect to the output side AC terminal T of the (i-1)th AC / AC module i-1,12 The output AC terminal T of the j-th AC / AC module j,11 Connect to the output side AC terminal T of the (j-1)th AC / AC module j-1,12 .

[0080] like Figure 2 The diagram shown illustrates the AC / AC module structure of an embodiment of the energy feedback high-capacity high-frequency transformer test power supply topology of the present invention. It contains M+N AC / AC modules, with the k-th AC / AC module comprising an AC / DC power unit k, a DC / AC power unit k, and a bypass switch SW. k , 1≤k≤M+N:

[0081] The first output terminal T of the AC / DC power unit k,7a first input terminal T connected to the DC / AC power unit k,9 a second output terminal T of the AC / DC power unit k,8 a second input terminal T connected to the DC / AC power unit k,10 three input terminals of the AC / DC power unit are three input terminals T k,4 , T k,5 and Tk j,6 of the AC / AC module k,11 two output terminals of the DC / AC power unit are two output terminals T k,12 , T k , and a bypass switch SW M+N is arranged between the two output terminals.

[0082] The AC / DC power units 1-AC / DC power unit (M+N) are three-phase voltage source converters, which are used to provide DC bus voltage or DC power for the DC / AC power units.

[0083] The DC / AC power units 1-DC / AC power unit (M+N) are single-phase voltage source converters, which are used to provide square wave voltage for the primary side and the secondary side of the large-capacity high-frequency transformer to be tested.

[0084] The bypass switches SW1-bypass switch SW M+N are used to bypass the AC side output of the DC / AC power unit to expand the voltage range of the test loop of the large-capacity high-frequency transformer.

[0085] The first resonant capacitor is arranged in series at the first output terminal T 1,11 of the first AC / AC module of the M AC / AC modules and the first input terminal P1 of the high-voltage side of the large-capacity high-frequency transformer to be tested.

[0086] The second resonant capacitor is arranged in series at the first output terminal T M+1,11 of the first AC / AC module of the N AC / AC modules and the first input terminal S1 of the low-voltage side of the large-capacity high-frequency transformer to be tested.

[0087] The first bypass switch is arranged in parallel with the first resonant capacitor, and the second bypass switch is arranged in parallel with the second resonant capacitor.

[0088] When the large-capacity high-frequency transformer to be tested needs to operate in a resonant operation mode, the first bypass switch and the second bypass switch are opened, and the first resonant capacitor and the second resonant capacitor respectively resonate with the inductance in the primary side and the secondary side loop of the large-capacity high-frequency transformer to be tested, so that the large-capacity high-frequency transformer to be tested operates in the resonant operation mode.

[0089] When the high-capacity high-frequency transformer under test needs to be operated in phase-shifting mode, close the first bypass switch and the second bypass switch to bypass the first resonant capacitor and the second resonant capacitor, so that the high-capacity high-frequency transformer under test can be operated in phase-shifting mode.

[0090] The control method for the energy feedback large-capacity high-frequency transformer test power supply topology of the second embodiment of the present invention, based on the above-described energy feedback large-capacity high-frequency transformer test power supply topology, includes:

[0091] Let U be the DC bus voltage of the AC / DC power unit of the k-th AC / AC module in the M+N AC / AC modules. dck U dck Satisfying equations (1) and (2):

[0092]

[0093]

[0094] Where 1≤k≤M+N, U N,H and U N,L These are the AC bypass switches SW1 to SW1 of the DC / AC power units of the M+N AC / AC modules. M+N When disconnected, test the high-voltage side rated voltage and low-voltage side rated voltage of the energy feedback high-capacity high-frequency transformer test power supply topology;

[0095] The high-voltage side voltage U of the large-capacity high-frequency transformer to be tested H Its range is shown in equation (3):

[0096]

[0097] Where, δ max,H and δ min,H Let δ be the maximum and minimum regulation coefficients of the DC bus voltage for AC / DC power units 1 to M in the M AC / AC modules, respectively, and let δ be the maximum and minimum regulation coefficients of the DC bus voltage for AC / DC power units 1 to M in the M AC / AC modules. min,H <1<δ max,H m SW This refers to the number of power units from AC / DC power unit 1 to AC / DC power unit M in M ​​AC / AC modules that are bypassed by the AC side bypass switch, where 1 ≤ m. SW ≤M-1;

[0098] The low-voltage side voltage U of the large-capacity high-frequency transformer to be tested L Its range is shown in equation (4):

[0099]

[0100] Where, δmax,L and δ min,L Let δ represent the maximum and minimum regulation coefficients of the DC bus voltage for AC / DC power units (M+1) to AC / DC power units (M+N) in N AC / AC modules, respectively, and let δ min,L <1<δ max,L ;n SW This refers to the number of power units in the N AC / AC modules, from AC / DC power units (M+1) to AC / DC power units (M+N), that are bypassed by the AC-side bypass switch, where 1 ≤ n. SW ≤N-1;

[0101] The maximum active power P of the large-capacity high-frequency transformer under test was tested using a power supply topology with energy feedback. max As shown in equation (5):

[0102]

[0103] Among them, P N The rated power of the power supply topology for testing large-capacity high-frequency transformers with energy feedback is δ. H δ L These are the DC bus voltage regulation coefficients for AC / DC power units 1 to M in M ​​AC / AC modules, and the DC bus voltage regulation coefficients for AC / DC power units M+1 to M+N in N AC / AC modules, respectively.

[0104] like Figure 3 As shown, this is an embodiment of the energy feedback high-capacity high-frequency transformer test power supply topology of the present invention. The AC / DC power unit q(M+1≤q≤M+Nn) of the high-capacity high-frequency transformer under test is operating in resonant mode. SW The DC voltage closed-loop and power feedforward outer loop control block diagram shows the operation control process of the energy feedback high-capacity high-frequency transformer test power supply topology when the transformer under test needs to operate in resonant mode:

[0105] With the first and second bypass switches in the open state, the grid-side voltage of the primary winding of the three-phase multi-winding transformer is phase-locked through the controller of the energy feedback high-capacity high-frequency transformer test power supply topology to obtain the real-time phase of the grid voltage.

[0106] The AC / DC power unit p (1≤p≤Mm) is stabilized by using an outer loop DC bus voltage closed-loop control and an inner loop AC side current closed-loop control. SW The DC bus voltage is controlled by an outer loop DC voltage closed-loop and power feedforward, and an inner loop AC side current closed-loop control for AC / DC power units q(M+1≤q≤M+Nn). SW) to control the active power, and to stabilize the DC voltage of the AC / DC power unit. In order to realize the energy feedback large-capacity high-frequency transformer test power supply topology, the rated electrical parameters of the AC / DC power unit (M+1) to the AC / DC power unit (M+N) are selected to be consistent, the rated electrical parameters of the DC / AC power unit (M+1) to the DC / AC power unit (M+N) are selected to be consistent, and the reference current of the outer loop power feed of the AC / DC power unit q is shown in formula (6):

[0107]

[0108] wherein, P ref,T is the operating power instruction of the large-capacity high-frequency transformer to be tested, γ is the operating efficiency of the AC / DC power unit q, ε is the operating efficiency of the DC / AC power unit q, U acL is the rated voltage of the AC side of the AC / DC power unit q;

[0109] The reference current generated by the outer loop DC voltage controller is shown in formula (7):

[0110]

[0111] wherein, the voltage controller is shown in formula (8):

[0112]

[0113] wherein, k 1,q and k 2,q are proportional coefficient and integral coefficient respectively;

[0114] The reference current of the AC / DC power unit q is shown in formula (9):

[0115] I refq = I ref + ΔI refq (9)

[0116] The AC / DC power unit (M-m SW +1) to the AC / DC power unit M and the AC / DC power unit (M+N-n SW +1) to the AC / DC power unit (M+N) are locked, the bypass switch to the bypass switch SW M and the bypass switch to the bypass switch SW M+N are placed in the closed state, and other bypass switches are placed in the open state, the DC / AC power unit (M-m SW +1) to the DC / AC power unit M are locked, and the DC / AC power unit (M+N-n SW+1)~DC / AC power unit (M+N) latching, DC / AC power unit 1~DC / AC power unit (M-m SW ), the large-capacity high-frequency transformer to be tested and DC / AC power unit (M+1)~DC / AC power unit (M+N-n SW ) constitute a resonant dual active bridge converter, the controller controls the AC side output of the DC / AC power unit which is not bypassed to be a square wave voltage, the AC side voltage frequency is the same as the rated frequency of the large-capacity high-frequency transformer to be tested, and the AC side output voltages of DC / AC power unit 1~DC / AC power unit (M-m SW ) and DC / AC power unit (M+1)~DC / AC power unit (M+N-n SW ) are in phase, so that the primary side and secondary side voltages of the large-capacity high-frequency transformer to be tested are square wave voltages, the controller issues power instructions of AC / DC power unit (M+1)~AC / DC power unit (M+N-n SW ) to make it feed power to the grid or take power from the grid, and adjusts the power instructions to make the large-capacity high-frequency transformer to be tested operate in a rated state;

[0117] When AC / DC power unit M+1~AC / DC power unit M+N-n SW feed power to the grid, the energy flow in the large-capacity high-frequency transformer test power supply topology is as follows: energy flows from secondary three-phase winding 1~secondary three-phase winding M-m SW to AC / DC power unit 1~AC / DC power unit (M-m SW ) respectively, and then flows to DC / AC power unit 1~DC / AC power unit (M-m SW ) through the DC bus in AC / AC module 1~AC / AC module M respectively, and then flows to the primary winding of the large-capacity high-frequency transformer to be tested through the AC output of DC / AC power unit 1~DC / AC power unit (M-m SW ), and flows to the secondary winding of the large-capacity high-frequency transformer to be tested through electromagnetic induction, and then flows to the DC side through the AC side of DC / AC power unit (M+1)~DC / AC power unit (M+N-n SW ), and AC / DC power unit (M+1)~AC / DC power unit (M+N-n SW ) feeds the DC side power into secondary three-phase winding (M+1)~secondary three-phase winding (M+N-n SW ) of the multi-winding transformer respectively;

[0118] When DC / AC power unit (M+1)~DC / AC power unit (M+N-n SW) from the power grid, the energy flow path is opposite to the above, the energy flow path can be inferred by referring to the above process, the present application does not detail here.

[0119] When the to-be-tested large-capacity high-frequency transformer needs to operate in a phase-shift operation mode, the energy feedback large-capacity high-frequency transformer test power supply topology operation control process is:

[0120] The first bypass switch and the second bypass switch are placed in a closed state, and the controller of the energy feedback large-capacity high-frequency transformer test power supply topology phase-locks the grid-side voltage of the primary winding of the three-phase multi-winding transformer to obtain the real-time phase of the grid voltage;

[0121] The DC bus voltage of the DC / AC power unit (1≤t≤M-m SW , M+1≤t≤M+N-n SW ) is controlled by adopting outer loop DC bus voltage closed loop and inner loop AC side current closed loop, the bypass switch ~ the bypass switch SW M and the bypass switch ~ the bypass switch SW M+N are placed in a closed state, other bypass switches are placed in an open state, the DC / AC power unit (M-m SW +1)~DC / AC power unit M is locked, the DC / AC power unit (M+N-n SW +1)~DC / AC power unit (M+N) is locked, the DC / AC power unit 1~DC / AC power unit (M-m SW ), the to-be-tested large-capacity high-frequency transformer and the DC / AC power unit (M+1)~DC / AC power unit (M+N-n SW ) constitute a phase-shift dual active bridge converter, the controller controls the AC side output of the DC / AC power unit which is not bypassed to be a square wave voltage, the AC side voltage frequency is the same as the rated frequency of the to-be-tested large-capacity high-frequency transformer, the AC side output voltages of the DC / AC power unit 1~DC / AC power unit (M-m SW ) are controlled to be in phase, the AC side output voltages of the DC / AC power unit (M+1)~DC / AC power unit (M+N-n SW ) are controlled to be in phase, the AC side output voltage phase of the DC / AC power unit (M+1)~DC / AC power unit (M+N-n SW ) is controlled, so that u s phase lags behind or leads u p , and the to-be-tested large-capacity high-frequency transformer operates in a rated capacity state, wherein u p is the sum of the AC output voltages of all DC / AC power units on the high-voltage side of the to-be-tested large-capacity high-frequency transformer, u sThe sum of AC output voltages of all DC / AC power units on the low-voltage side of the large-capacity high-frequency transformer to be tested;

[0122] When u s is ahead of u p , the energy flow in the energy feedback large-capacity high-frequency transformer test power supply topology is as follows: energy flows from the secondary three-phase winding 1 to the secondary three-phase winding (M-m SW ) respectively to the AC / DC power unit 1 to the AC / DC power unit (M-m SW ), and then flows to the DC / AC power unit 1 to the DC / AC power unit (M-m SW ) through the DC bus in the AC / AC module 1 to the AC / AC module (M-m SW ), and then flows to the primary winding of the large-capacity high-frequency transformer to be tested through the AC output of the DC / AC power unit 1 to the DC / AC power unit (M-m SW ), and then flows to the secondary winding of the large-capacity high-frequency transformer to be tested through electromagnetic induction, and then flows to the DC side through the AC side of the DC / AC power unit M+1 to the DC / AC power unit (M+N-n SW ), and since the AC / DC power unit M+1 to the AC / DC power unit M+N operates in the controlled DC voltage source mode, it feeds the power on the DC side into the secondary three-phase winding M+1 to the secondary three-phase winding (M+N-n SW ) of the multi-winding transformer respectively.

[0123] When u s is ahead of u p , the energy flow path is opposite to that when u s is behind u p , and the energy flow path when u s is ahead of u p can be inferred by referring to the energy flow path when u s is behind u p , and the present application will not be described in detail here.

[0124] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process and related description of the above-described method can refer to the corresponding process in the foregoing system embodiment, and will not be described here.

[0125] It should be noted that the energy feedback large-capacity high-frequency transformer test power supply topology and control method provided by the above embodiments are only exemplified by the division of the above functional modules, and in actual application, the above functions can be completed by different functional modules according to needs, that is, the modules or steps in the embodiments of the present application are further decomposed or combined, for example, the modules of the above embodiments can be combined into one module, or can be further split into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present application are only for distinguishing the respective modules and steps, and should not be considered as improper limitation of the present application.

[0126] The device of the third embodiment of the present application comprises:

[0127] at least one processor; and

[0128] a memory in communication with the at least one processor; wherein

[0129] The memory stores instructions executable by the processor, and the instructions are executed by the processor to implement the control method of the energy feedback large-capacity high-frequency transformer test power supply topology described above.

[0130] The computer readable storage medium of the fourth embodiment of the present application stores computer instructions, and the computer instructions are executed by the computer to implement the control method of the energy feedback large-capacity high-frequency transformer test power supply topology described above.

[0131] Those skilled in the art can clearly understand the specific working processes of the storage device and the processing device described above and the related descriptions, which can be referred to the corresponding processes in the foregoing method embodiments for description convenience and brevity, and will not be described here.

[0132] Those skilled in the art should realize that the modules and method steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware, computer software or a combination of both. The programs corresponding to the software modules and method steps can be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. In order to clearly illustrate the interchangeability of electronic hardware and software, the components and steps of each example have been generally described in the foregoing description. Whether the functions are performed by electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0133] The 3kV / 1kV / 10kHz / 1MW energy feedback large-capacity high-frequency transformer test power supply topology built by applying the present application is used for temperature field test simulation, and the simulation parameters are as follows:

[0134] The effective value of the primary three-phase winding voltage of the multi-winding transformer: 380V;

[0135] The effective value of the secondary three-phase winding voltage of the multi-winding transformer: 380V;

[0136] The number of the secondary three-phase winding of the multi-winding transformer corresponding to the high-voltage side AC / DC power unit of the large-capacity high-frequency transformer to be tested, i.e. the number M of the high-voltage side AC / AC module of the large-capacity high-frequency transformer to be tested: 4;

[0137] The number of the secondary three-phase winding of the multi-winding transformer corresponding to the low-voltage side AC / DC power unit of the large-capacity high-frequency transformer to be tested, i.e. the number N of the low-voltage side AC / AC module of the large-capacity high-frequency transformer to be tested: 2;

[0138] The DC bus voltage of the AC / DC power unit 1-AC / DC power unit 6: 750V;

[0139] The rated capacity of the AC / DC power unit 1-AC / DC power unit 4 and the DC / AC power unit 1-DC / AC power unit 4: 300kVA;

[0140] The rated capacity of the AC / DC power unit 5-AC / DC power unit 6 and the DC / AC power unit 5-DC / AC power unit 6: 600kVA;

[0141] The first resonance capacitor: 8.4μF;

[0142] The second resonance capacitor: 50.66μF;

[0143] The rated capacity of the large-capacity high-frequency transformer to be tested: 1.2MVA;

[0144] The transformation ratio of the large-capacity high-frequency transformer to be tested: 3000:1500;

[0145] The rated working frequency of the large-capacity high-frequency transformer to be tested: 10kHz;

[0146] The switching frequency of each DC / AC power unit and the resonance frequency when the large-capacity high-frequency transformer to be tested operates in the resonance state: 10kHz;

[0147] The high-voltage side leakage inductance of the large-capacity high-frequency transformer to be tested: 30μH;

[0148] The low-voltage side leakage inductance of the large-capacity high-frequency transformer to be tested: 5μH.

[0149] Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 are respectively five simulation results of the to-be-tested large-capacity high-frequency transformer operating in the resonance mode. Figure 4 u p , i p are respectively the sum of the AC output voltages of the DC / AC power units 1-4 and the high-voltage side winding current of the to-be-tested large-capacity high-frequency transformer. s , i s are respectively the sum of the AC output voltages of the DC / AC power units 5-6 and the low-voltage side winding current of the to-be-tested large-capacity high-frequency transformer. It can be known from the simulation results that the to-be-tested large-capacity high-frequency transformer operates in the resonance state, and the active power is 1 MW. Figure 5 u dc1 , u dc2 , u dc3 , u dc4 , u dc5 , u dc6 are respectively the DC bus voltages of the AC / DC power units 1-6. It can be known from the simulation results that the power among the AC / DC power units is balanced. Figure 6 u A , u B , u C are the primary three-phase winding voltages of the multi-winding transformer, i 1,a , i 1,b , i 1,c are the three-phase AC currents of the AC / DC power unit 1. It can be known from the simulation results that the AC / DC power unit 1 is connected to the grid with a unit power factor, and the active power is 250 kW. Figure 7 i 5,a , i 5,b , i 5,c are the three-phase AC currents of the AC / DC power unit 5. It can be known from the simulation results that the AC / DC power unit 5 is connected to the grid with a unit power factor, and the active power is 500 kW. Figure 8 i A , i B , i C are the primary three-phase winding currents of the multi-winding transformer. It can be known from the simulation results that the primary three-phase winding currents of the multi-winding transformer are very small, and the power absorbed from the grid is very small, which is only used to compensate for the losses of the energy feedback large-capacity high-frequency transformer test power supply and the to-be-tested large-capacity high-frequency transformer, thereby reducing the waste of electric energy.

[0150] Figure 9 、 Figure 10 ,Figure 11 、 Figure 12 、 Figure 13 are respectively five simulation results of the large-capacity high-frequency transformer to be tested operating in the phase-shift control mode. Figure 9 u p , i p are respectively the sum of the AC output voltages of the DC / AC power units 1-4 and the high-voltage side winding current of the large-capacity high-frequency transformer to be tested. s , i s are respectively the sum of the AC output voltages of the DC / AC power units 5-6 and the low-voltage side winding current of the large-capacity high-frequency transformer to be tested. It can be seen from the simulation results that the large-capacity high-frequency transformer to be tested operates in the resonance state, and the apparent power is 1.2 MVA, and the active power is 1 MW. Figure 10 u dc1 , u dc2 , u dc3 , u dc4 , u dc5 , u dc6 are respectively the DC bus voltages of the AC / DC power units 1-6. It can be seen from the simulation results that the power among the AC / DC power units is balanced. Figure 11 u A , u B , u C are the primary three-phase winding voltages of the multi-winding transformer, i 1,a , i 1,b , i 1,c are the three-phase AC currents of the AC / DC power unit 1. It can be seen from the simulation results that the AC / DC power unit 1 is connected to the grid with a unit power factor, and the active power is 250 kW. Figure 12 i 5,a , i 5,b , i 5,c are the three-phase AC currents of the AC / DC power unit 5. It can be seen from the simulation results that the AC / DC power unit 5 is connected to the grid with a unit power factor, and the active power is 500 kW. Figure 13 i A , i B , i C are the primary three-phase winding currents of the multi-winding transformer. It can be seen from the simulation results that the primary three-phase winding currents of the multi-winding transformer are very small, and the power absorbed from the grid is very small. The absorbed power is only used to compensate for the power supply and transformer losses during the test of the large-capacity high-frequency transformer, reducing the waste of electrical energy.

[0151] The terms "first", "second", and the like are used to distinguish similar objects, rather than to describe or indicate a particular order or sequence.

[0152] The term "comprising" or any other similar word is intended to encompass the inclusion of one or more steps, features, or elements but not to the exclusion of any other steps, features, or elements. The term "comprising" therefore indicates that the inclusion of one or more steps, features, or elements is not a requirement and that other steps, features, or elements can also be included.

[0153] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without deviating from the principles of the present application, and the technical solutions after these changes or replacements will all fall within the protection scope of the present application.

Claims

1. A topology of energy feedback bulk high frequency transformer test power supply, characterized in that, The power supply topology comprises: a three-phase multi-winding transformer, comprising one primary three-phase winding, M secondary three-phase windings corresponding to the AC / DC power units of the AC / AC modules on the high-voltage side of the large-capacity high-frequency transformer to be tested, and N secondary three-phase windings corresponding to the AC / DC power units of the AC / AC modules on the low-voltage side of the large-capacity high-frequency transformer to be tested, M≥N; M+N AC / AC modules corresponding to the M secondary three-phase windings and the N secondary three-phase windings respectively; a first resonant capacitor connected in series between the first output end of the first AC / AC module of the M AC / AC modules and the first input end of the high-voltage side of the large-capacity high-frequency transformer to be tested; a second resonant capacitor connected in series between the first output end of the first AC / AC module of the N AC / AC modules and the first input end of the low-voltage side of the large-capacity high-frequency transformer to be tested; a first bypass switch connected in parallel with the first resonant capacitor, and a second bypass switch connected in parallel with the second resonant capacitor; when the large-capacity high-frequency transformer to be tested needs to operate in a resonant mode, the first bypass switch and the second bypass switch are opened, and the first resonant capacitor and the second resonant capacitor resonate with the inductance in the primary and secondary circuits of the large-capacity high-frequency transformer to be tested respectively, so that the large-capacity high-frequency transformer to be tested operates in the resonant mode; when the large-capacity high-frequency transformer to be tested needs to operate in a phase-shifting mode, the first bypass switch and the second bypass switch are closed, bypassing the first resonant capacitor and the second resonant capacitor, so that the large-capacity high-frequency transformer to be tested operates in the phase-shifting mode.

2. The energy feedback high-power high-frequency transformer test power supply topology according to claim 1, characterized in that, The primary three-phase winding has three AC terminals T P1 , T P2 , and T P3 connected to the A-phase, B-phase, and C-phase of a three-phase AC power grid, respectively.

3. The energy feedback high-power high-frequency transformer test power supply topology of claim 1, wherein, The M secondary side three-phase windings, three AC terminals T i,1 ,and T i,2 of the i-th secondary side three-phase winding are respectively connected to the input side three AC terminals T i,3 , T i,4 , and T i,5 of the corresponding AC / AC module. i,6 The N secondary side three-phase windings, the jth secondary side three-phase winding three AC terminals T j,1 , j,2 and T j,3 are connected to the corresponding AC / AC module input side three AC terminals T j,4 , j,5 and T j,6 respectively; wherein 1≤i≤M, M+1≤j≤M+N.

4. The energy feedback high-power high-frequency transformer test power supply topology of claim 3, wherein, The M+N AC / AC modules, the output side AC terminal T of the first AC / AC module 1,11 The terminal T connected to the first resonant capacitor r1,1 The terminal T of the first resonant capacitor r1,2 The first input end P1 connected to the high voltage side of the large-capacity high-frequency transformer to be tested, the output side AC terminal T of the Mth AC / AC module M,12 The second input end P2 connected to the high voltage side of the large-capacity high-frequency transformer to be tested, the output side AC terminal T of the M+1th AC / AC module M+1,11 The terminal T connected to the second resonant capacitor r2,2 The terminal T of the second resonant capacitor r2,1 The first input end S1 connected to the low voltage side of the large-capacity high-frequency transformer to be tested, the output side AC terminal T of the M+Nth AC / AC module M+N,12 The second input end S2 connected to the low voltage side of the large-capacity high-frequency transformer to be tested, the output side AC terminal T of the ith AC / AC module i,11 The output side AC terminal T connected to the i-1th AC / AC module i-1,12 The output side AC terminal T of the jth AC / AC module j,11 The output side AC terminal T connected to the j-1th AC / AC module j-1,12 ​ 5. The energy feedback high-power high-frequency transformer test power supply topology of claim 1, wherein, the M+N AC / AC modules, a kth AC / AC module comprising an AC / DC power unit k, a DC / AC power unit k and a bypass switch SW k , 1≤k≤M+N.

6. A control method of an energy feedback large-capacity high-frequency transformer test power supply topology, based on any one of claims 1-5, the control method comprising: Let the DC bus voltage of the AC / DC power unit of the kth AC / AC module in the M+N AC / AC modules be denoted as U dck , and satisfy and, wherein 1≤k≤M+N, U N,H and U N,L are respectively the AC bus voltage of the DC / AC power unit of the M+N AC / AC modules, and the DC bus voltage of the DC / AC power unit of the M+N AC / AC modules. M+N The rated voltage of the high-voltage side and the rated voltage of the low-voltage side of the energy feedback large-capacity high-frequency transformer test power supply topology when the AC bypass switches SW1-SW The high voltage side voltage U of the high-capacity high-frequency transformer to be tested H ranging from: wherein δ max,H and δ min,H are the maximum and minimum regulating coefficients of the DC bus voltage of the AC / DC power unit 1-AC / DC power unit M in the M AC / AC modules, respectively, and δ min,H <1<δ max,H ; m SW is the number of power units of the AC / DC power unit 1-AC / DC power unit M in the M AC / AC modules which are bypassed by the AC-side bypass switch, 1≤m SW ≤M-1; The low voltage side voltage U of the high-capacity high-frequency transformer to be tested L ranging from: wherein δ max,L and δ min,L are respectively the maximum and minimum regulating coefficients of the DC bus voltage of the AC / DC power unit (M+1) to the AC / DC power unit (M+N) in the N AC / AC modules, and δ min,L <1<δ max,L ; n SW is the number of power units bypassed by the AC side bypass switch among the AC / DC power unit (M+1) to the AC / DC power unit (M+N) in the N AC / AC modules, 1≤n SW ≤N-1. The maximum active power P for testing a large-capacity high-frequency transformer to be tested by an energy feedback large-capacity high-frequency transformer test power supply topology max is: where P N is the rated power of the energy feedback large-capacity high-frequency transformer test power supply topology, δ H , δ L are the DC bus voltage regulation coefficients of the AC / DC power units 1-AC / DC power units M in the M AC / AC modules and the DC bus voltage regulation coefficients of the AC / DC power units M+1-AC / DC power units M+N in the N AC / AC modules, respectively.

7. The control method of the energy feedback high-capacity high-frequency transformer test power supply topology according to claim 6, characterized in that, when the large-capacity high-frequency transformer to be tested needs to operate in a resonant mode, the operation control process of the energy feedback large-capacity high-frequency transformer test power supply topology is: placing the first bypass switch and the second bypass switch in an open state, and using the controller of the energy feedback large-capacity high-frequency transformer test power supply topology to phase-lock the grid-side voltage of the primary winding of the three-phase multi-winding transformer to obtain the real-time phase of the grid voltage; The AC / DC power unit p (1≤p≤Mm) is stabilized by using an outer loop DC bus voltage closed-loop control and an inner loop AC side current closed-loop control. SW The DC bus voltage is controlled by an outer loop DC voltage closed-loop and power feedforward, and an inner loop AC side current closed-loop control for AC / DC power units q(M+1≤q≤M+Nn). SW The active power of the AC / DC power unit (Mm) is controlled. SW +1)~AC / DC power unit M and AC / DC power unit (M+Nn) SW +1) ~ AC / DC power unit (M+N) interlock, bypass switch Bypass switch SW M With bypass switch Bypass switch SW M+N With the circuit breaker in the closed position and other bypass switches in the open position, the DC / AC power unit (Mm) is in the closed position. SW +1) ~ DC / AC power unit M is locked, DC / AC power unit (M+Nn) SW +1)~DC / AC power unit (M+N) is locked, DC / AC power unit 1~DC / AC power unit (Mm) SW ), the large-capacity high-frequency transformer under test and the DC / AC power unit (M+1) to DC / AC power unit (M+Nn) SW This forms a resonant dual active bridge converter. The controller controls the AC output of the unbypassed DC / AC power unit to be a square wave voltage. The frequency of the AC voltage is the same as the rated frequency of the large-capacity high-frequency transformer under test. This controls DC / AC power unit 1 to DC / AC power unit (Mm)... SW ) and DC / AC power unit (M+1) to DC / AC power unit (M+Nn) SW The AC output voltage is in phase, therefore the primary and secondary voltages of the large-capacity high-frequency transformer under test are square wave voltages. The controller sends AC / DC power unit (M+1) to AC / DC power unit (M+Nn) voltages. SW The power command is given to enable the transformer to feed power to or draw power from the grid, and the power command is adjusted to make the large-capacity high-frequency transformer under test operate at its rated state.

8. The control method of the energy feedback high-capacity high-frequency transformer test power supply topology according to claim 6, characterized in that, when the large-capacity high-frequency transformer to be tested needs to operate in a phase-shifting mode, the operation control process of the energy feedback large-capacity high-frequency transformer test power supply topology is: placing the first bypass switch and the second bypass switch in a closed state, and using the controller of the energy feedback large-capacity high-frequency transformer test power supply topology to phase-lock the grid-side voltage of the primary winding of the three-phase multi-winding transformer to obtain the real-time phase of the grid voltage; The DC / AC power unit t (1≤t≤Mm) is stabilized by using an outer loop DC bus voltage closed-loop control and an inner loop AC side current closed-loop control. SW M+1≤t≤M+Nn SW DC bus voltage, bypass switch Bypass switch SW M With bypass switch Bypass switch SW M+N With the circuit breaker in the closed position and other bypass switches in the open position, the DC / AC power unit (Mm) is in the closed position. SW +1) ~ DC / AC power unit M is locked, DC / AC power unit (M+Nn) SW +1)~DC / AC power unit (M+N) is locked, DC / AC power unit 1~DC / AC power unit (Mm) SW ), the large-capacity high-frequency transformer under test and the DC / AC power unit (M+1) to DC / AC power unit (M+Nn) SW This constitutes a phase-shifting dual active bridge converter. The controller controls the AC output of the unbypassed DC / AC power unit to be a square wave voltage. The frequency of the AC voltage is the same as the rated frequency of the large-capacity high-frequency transformer under test. This controls DC / AC power unit 1 to DC / AC power unit (Mm)... SW The AC side output voltage is in phase, controlling the DC / AC power unit (M+1) to the DC / AC power unit (M+Nn). SW The AC side output voltage is in phase, controlling the DC / AC power unit (M+1) to the DC / AC power unit (M+Nn). SW The phase of the AC side output voltage of ) makes u s Phase lag or lead u p Furthermore, the large-capacity high-frequency transformer under test is operating at its rated capacity, where u p u is the sum of the AC output voltages of all DC / AC power units on the high-voltage side of the large-capacity high-frequency transformer under test. s This is the sum of the AC output voltages of all DC / AC power units on the low-voltage side of the large-capacity high-frequency transformer under test.

Images