A high voltage DC transformer and system

Abstract

The invention discloses a high-voltage direct current transformer and a system. The transformer comprises: a primary side of a multi-winding transformer connected to a DC / AC module, a secondary side of the multi-winding transformer connected to a first AC / DC module and / or a second AC / DC module, wherein the DC / AC module converts high-voltage direct current into alternating current, and the first AC / DC module and the second AC / DC module directly convert alternating current into direct current to supply power to a load and a common direct current bus, respectively, thereby realizing direct conversion of high voltage to efficiently supply power to the load, and having the advantages of fewer conversion links, higher efficiency, and diversified ports, etc. The first AC / DC module is internally composed of one or more voltage converters, and the output voltage of the first AC / DC module can be finely adjusted in a wide power range by accurately adjusting the output voltage of the voltage converter, thereby being more suitable for electrolysis fields such as electrolysis of water to produce hydrogen, which require adjusting the output current within a small voltage range or have a large power range.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current power supply, and in particular to a high-voltage direct current transformer and a system. Background Art

[0002] DC transmission and distribution technology has developed rapidly in the fields of high-voltage transmission network, medium-voltage distribution network and microgrid due to its unique technical advantages. Its core is DC conversion technology or DC transformer technology, which is responsible for converting high-voltage DC to low-voltage DC. Usually, the voltage level conversion span is large, requiring the input and output of the conversion device to be relatively large, and the output voltage needs to be adjustable within a certain range, and even the output port of the conversion device needs to be directly connected to the load, or the output port needs to have multiple voltage levels.

[0003] The existing technology usually uses a multi-stage conversion method to achieve DC conversion between high and low voltage and multiple ports. There are problems such as many conversion device links, large losses, complex control, and low regulation accuracy. It is difficult to achieve high-voltage direct power supply to the load and improve conversion efficiency and regulation accuracy. For example, in the application field of new energy DC microgrid hydrogen production, it is usually necessary to convert high-voltage DC into low-voltage DC and then electrolyze water to produce hydrogen. It is usually achieved by cascading two or more power conversion units. The first stage converts the high-voltage DC voltage into a low-level public DC voltage. The second stage usually adjusts the public DC voltage to a wide power range voltage to power the electrolyzer. At the same time, the electrolysis process is usually carried out within a smaller voltage range (such as 170V ~ 200V). Although the output voltage range of traditional power supplies can be wider (such as 0V ~ 200V), its effective working range during electrolysis is narrow (such as 200V-170V=30V), and within this smaller voltage range, the electrolysis power needs to be adjusted from no-load to full-load full power. Therefore, it is more difficult to adjust the output power with high precision within a narrow range (30V). Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the multi-stage conversion method in the prior art, such as many conversion device links, large losses, complex control, and difficulty in adjusting the output high-precision power within a narrow range, thereby providing a high-voltage DC transformer and system.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a high-voltage direct current transformer, including: a DC / AC module, a multi-winding transformer, a first AC / DC module and / or a second AC / DC module, wherein the DC / AC module includes a total input positive pole, a total input negative pole, and multiple groups of output terminals, wherein the total input positive pole of the DC / AC module is connected to the high-voltage direct current positive pole, the total input negative pole of the DC / AC module is connected to the high-voltage direct current negative pole, each group of output terminals of the DC / AC module is connected to two input terminals of a primary winding of the multi-winding transformer, and the DC / AC module is used to convert high-voltage direct current into medium- and low-frequency alternating current; the first group of input terminals of the first AC / DC module is connected to the two ends of a winding of the multi-winding transformer, the second group of input terminals of the first AC / DC module is connected to the two ends of another winding of the multi-winding transformer, and the first output terminal, the second The output end is respectively connected to the positive electrode and the negative electrode of the load power supply end of the corresponding voltage level. The first AC / DC module is used to convert medium and low frequency alternating current into direct current to supply power to the load of the corresponding voltage level; the first AC / DC module is composed of one or more voltage converters, and the output voltage of the voltage converter is adjusted so that the output voltage range of the first AC / DC module is the difference between the upper limit voltage and the lower limit voltage of the load effective working voltage; the first input end and the second input end of the second AC / DC module are respectively connected to the first output end and the second output end of a secondary winding of the multi-winding transformer, the first output end and the second output end of the second AC / DC are respectively connected to the positive electrode and the negative electrode of the common DC bus of the corresponding voltage level, and the second DC / DC module is used to convert medium and low frequency alternating current into direct current to supply power to the common DC bus of the corresponding voltage level.

[0007] In one embodiment, when there are two or more first AC / DC modules, two output terminals of the first AC / DC modules outputting the same level of voltage are connected in parallel and then connected to the positive and negative terminals of the power supply terminal of the load respectively.

[0008] In one embodiment, the DC / AC module is a series circuit composed of multiple DC / AC converters, wherein the first input end of the DC / AC converter at this stage in the series circuit is connected to the second input end of the DC / AC converter at the upper stage, the second input end of the DC / AC converter at this stage in the series circuit is connected to the first input end of the DC / AC converter at the lower stage, the first input end of the DC / AC converter at the first stage in the series circuit is connected to the positive pole of the high-voltage DC, the second input end of the DC / AC converter at the last stage in the series circuit is connected to the negative pole of the high-voltage DC, and the first output end and the second output end of each DC / AC converter in the series circuit are respectively connected to the two ends of a primary winding of a multi-winding transformer.

[0009] In one embodiment, the DC / AC converter and the second AC / DC module both include: any one of a half-bridge converter and a full-bridge converter.

[0010] In one embodiment, the first AC / DC module is composed of a first AC / DC converter, a second AC / DC converter, a first capacitor, a second capacitor, and a third capacitor, wherein the positive input terminal and the negative input terminal of the first AC / DC converter are connected to the two ends of a secondary winding of a multi-winding transformer, and the positive input terminal and the negative input terminal of the second AC / DC converter are connected to the two ends of a secondary winding of the multi-winding transformer; the positive output terminal of the first AC / DC converter is respectively connected to the first end of the first capacitor and the first end of the second capacitor, and the negative output terminal of the first AC / DC converter is respectively connected to the positive output terminal of the second AC / DC converter, the second end of the first capacitor, and the first end of the third capacitor; the negative output terminal of the second AC / DC converter is respectively connected to the second end of the third capacitor and the second end of the second capacitor; the first end and the second end of the second capacitor are respectively connected to the positive pole and the negative pole of the load power supply end of the corresponding voltage level, or the first end and the second end of the second capacitor are respectively connected in parallel with the first end and the second end of the second capacitor in other first AC / DC modules that output the same level of voltage, and then connected to the positive pole and the negative pole of the load power supply end.

[0011] In one embodiment, the first AC / DC module is composed of a first AC / DC converter, a second AC / DC converter, a DC / DC converter, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor and an inductor, wherein the positive input terminal and the negative input terminal of the first AC / DC converter are connected to the two ends of a secondary winding of a multi-winding transformer, and the positive input terminal and the negative input terminal of the second AC / DC converter are connected to the two ends of a secondary winding of the multi-winding transformer; the positive output terminal of the first AC / DC converter is respectively connected to the first end of the first capacitor and the positive input terminal of the DC / DC converter, and the negative output terminal of the first AC / DC converter is respectively connected to the second end of the first capacitor and the negative input terminal of the DC / DC converter; D The positive output end of the C / DC converter is connected to the first end of the inductor, and the negative output end of the DC / DC converter is respectively connected to the first end of the fourth capacitor, the first end of the third capacitor, and the positive output end of the second AC / DC converter; the negative output end of the second AC / DC converter is respectively connected to the second end of the third capacitor and the second end of the second capacitor; the second end of the inductor is connected to the second end of the fourth capacitor and the first end of the second capacitor; the first end and the second end of the second capacitor are respectively connected to the positive and negative poles of the load power supply end of the corresponding voltage level, or the first end and the second end of the second capacitor are respectively connected in parallel with the first end and the second end of the second capacitor in the first AC / DC module that outputs the same level of voltage, and then connected to the positive and negative poles of the load power supply end.

[0012] In one embodiment, the first AC / DC converter and the second AC / DC converter are any one of a diode uncontrolled rectifier, a thyristor half-controlled rectifier, a PWM fully-controlled rectifier, and a rectifier implemented with synchronous rectification technology.

[0013] In one embodiment, the DC / DC converter is any one of a boost DC-DC converter, a buck DC-DC converter, a buck-boost DC-DC converter, and a DC-DC converter using synchronous rectification technology.

[0014] In a second aspect, an embodiment of the present invention provides a high-voltage direct current transformer system, comprising: two or more high-voltage direct current transformers of the first aspect, wherein the input ends of all DC / AC modules are connected in series: the first input ends of the DC / AC modules at this stage are all connected to the second input ends of the DC / AC modules at the upper stage, the second input ends of the DC / AC modules at this stage are all connected to the first input ends of the DC / AC modules at the lower stage, the first input end of the DC / AC module at the first stage is connected to the positive pole of the high-voltage direct current, and the second input end of the DC / AC module at the last stage is connected to the negative pole of the high-voltage direct current; the first output ends of the first AC / DC modules that output the same level of voltage are connected in parallel to the positive pole of the corresponding load power supply end, and the second output ends of the first AC / DC modules that output the same level of voltage are connected in parallel to the negative pole of the corresponding load power supply end; the first output end of the second AC / DC module that outputs the same level of voltage is connected to the positive pole of the same common direct current bus, and the second output end of the second AC / DC module that outputs the same level of voltage is connected to the negative pole of the same common direct current bus.

[0015] The technical solution of the present invention has the following advantages:

[0016] 1. The high-voltage direct current transformer provided by the present invention comprises: a DC / AC module, a multi-winding transformer, a first AC / DC module and / or a second AC / DC module, the primary side of the multi-winding transformer is connected to the DC / AC module, the secondary side of the multi-winding transformer is connected to the first AC / DC module and / or the second AC / DC module, wherein the DC / AC module converts high-voltage direct current into alternating current, and the first AC / DC module and the second AC / DC module directly convert alternating current into direct current to supply power to the load and the common DC bus, respectively, thereby directly converting the high voltage to supply power to the load efficiently, with the advantages of fewer conversion links, higher efficiency, and diversified ports. The first AC / DC module is internally composed of one or more voltage converters, and the output voltage of the first AC / DC module can be finely adjusted over a wide power range by accurately adjusting the output voltage of the voltage converter, so that it is more suitable for electrolysis fields such as electrolysis of water to produce hydrogen, which need to adjust the output current within a small voltage range or have a large power range.

[0017] 2. The high-voltage direct current conversion system provided by the present invention is expanded by means of series input and parallel output through the high-voltage direct current transformer, so that the power supply mode of the entire system is more diversified. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1(a) to Figure 1(c) A composition diagram of a specific example of a high-voltage DC transformer provided by an embodiment of the present invention;

[0020] Figure 2 A composition diagram of another specific example of a high-voltage DC transformer provided by an embodiment of the present invention;

[0021] Figure 3 A composition diagram of another specific example of a high-voltage DC transformer provided by an embodiment of the present invention;

[0022] Figure 4(a) to Figure 4(g) The specific circuit structure of the DC / AC converter and the second AC / DC module provided in the embodiment of the present invention;

[0023] FIG. 5( a ) and FIG. 5( b ) are specific circuit structures of a first AC / DC module provided in an embodiment of the present invention;

[0024] FIG. 6( a ) and FIG. 6( b ) are specific circuit structures of the first AC / DC module provided in an embodiment of the present invention;

[0025] FIG7( a) is a circuit diagram of a diode uncontrolled rectifier provided in an embodiment of the present invention;

[0026] FIG7( b) is a circuit diagram of a thyristor half-controlled rectifier provided in an embodiment of the present invention;

[0027] FIG7( c ) is a circuit diagram of a PWM fully-controlled rectifier provided in an embodiment of the present invention;

[0028] FIG7( d ) is a circuit diagram of a typical rectifier implemented by the synchronous rectification technology provided in an embodiment of the present invention;

[0029] FIG8( a) is a circuit diagram of a boost DC-DC converter provided in an embodiment of the present invention;

[0030] FIG8( b ) is a circuit diagram of a step-down DC-DC converter provided in an embodiment of the present invention;

[0031] FIG8( c ) is a circuit diagram of a buck-boost DC-DC converter provided in an embodiment of the present invention;

[0032] FIG8( d) is a circuit diagram of a synchronous rectification type DC-DC converter provided in an embodiment of the present invention;

[0033] Fig. 9 A composition diagram of a specific example of a high-voltage direct current transformer system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] Example 1

[0039] An embodiment of the present invention provides a high voltage DC transformer, such as Figure 1(a) to Figure 1(c)As shown, it includes: a DC / AC module 1, a multi-winding transformer 2, a first AC / DC module 3 and / or a second AC / DC module 4, the DC / AC module 1 includes a total input positive pole, a total input negative pole, and multiple groups of output terminals, wherein the number of primary windings and secondary windings of the multi-winding transformer 2 can be the same or different, and there is no limitation here.

[0040] like Figure 1(a) to Figure 1(c) As shown, the total input positive pole of the DC / AC module 1 is connected to the positive pole of the high-voltage DC, the total input negative pole of the DC / AC module 1 is connected to the negative pole of the high-voltage DC, each group of output ends of the DC / AC module 1 is connected to two input ends of a primary winding of a multi-winding transformer 2, and the DC / AC module is used to convert high-voltage DC power into medium- and low-frequency AC power.

[0041] Specifically, the DC / AC module 1 of the embodiment of the present invention is composed of multiple inverters, and the input ends of all the inverters are connected in series. Each inverter converts the input high-voltage direct current into medium- and high-frequency alternating current, and then passes through the electromagnetic effect of the multi-winding transformer 2. The corresponding first AC / DC module 3 and the second AC / DC module 4 convert the induced alternating current into low-voltage direct current.

[0042] As shown in Figure 1(a) and Figure 1(b), the first group of input terminals of the first AC / DC module 3 are connected to the two ends of one winding of the multi-winding transformer 2, the second group of input terminals of the first AC / DC module 3 are connected to the two ends of another winding of the multi-winding transformer 2, the first output terminal and the second output terminal of the first AC / DC module 3 are respectively connected to the positive pole and the negative pole of the load power supply terminal of the corresponding voltage level, and the first AC / DC module 3 is used to convert medium and low frequency alternating current into direct current to supply power to the load of the corresponding voltage level.

[0043] Specifically, the first AC / DC module 3 of the embodiment of the present invention is internally composed of one or more voltage converters, and the output voltage of the voltage converter is accurately adjusted so that the output voltage range of the first AC / DC module 3 is the difference between the upper limit voltage and the lower limit voltage of the load effective working voltage.

[0044] Specifically, the number of load power supply terminals in the embodiment of the present invention may be one or more, wherein, when the number is multiple, each load power supply terminal can supply power to loads requiring different levels of power supply voltages. For example, as shown in FIG. 1(a) and FIG. 1(b), the first AC / DC module #1 to the first AC / DC module #k can obtain multiple levels of power supply voltages and can supply power to loads #1 to #M.

[0045] As shown in Figure 1(a) and Figure 1(c), the first input terminal and the second input terminal of the second AC / DC module 4 are respectively connected to the first output terminal and the second output terminal of a secondary winding of the multi-winding transformer 2, and the first output terminal and the second output terminal of the second AC / DC are respectively connected to the positive pole and the negative pole of the common DC bus of the corresponding voltage level. The second DC / DC module is used to convert medium and low frequency AC power into DC power to supply power to the common DC bus of the corresponding voltage level.

[0046] Specifically, the common DC bus of the embodiment of the present invention can be one or more, wherein, when the number is multiple, each common DC bus provides different levels of power supply voltage, for example: as shown in Figure 1(a) and Figure 1(c), the second AC / DC module #1 to the second AC / DC module #m can obtain multiple levels of power supply voltage, and the common DC bus #1 to the common DC bus #H can provide different DC voltages.

[0047] It should be noted that the DC output port of each AC / DC module is in a classified parallel connection relationship, and the DC port is not limited to the load port and the common DC output port.

[0048] In a specific embodiment, when there are two or more first AC / DC modules 3, two output ends of the first AC / DC modules 3 that output the same level of voltage are connected in parallel and then connected to the positive and negative poles of the power supply end of the load respectively.

[0049] Specifically, for example, the first output terminal and the second output terminal of the first AC / DC module #1 and the first AC / DC module #2 in FIG. 1( a ) can be directly connected to the positive electrode and the negative electrode of the load #1, or as shown in FIG. Figure 2 As shown, the first output terminal and the first output terminal of the first AC / DC module #1 are connected to the first output terminal and the second output terminal of the second AC / DC module #2 respectively, and then directly connected to the positive and negative electrodes of the load #1. No limitation is made here. It should be noted that this specific embodiment takes the structure of Figure 1(a) as an example, but when the high-voltage direct current multi-port conversion device is the structure of Figure 1(b) or Figure 1(c), the output terminals of the first AC / DC modules 3 that output the same level of voltage are connected in parallel and then connected to the positive and negative electrodes of the power supply terminal of the load.

[0050] In a specific embodiment, if Figure 3As shown, the DC / AC module 1 is a series circuit composed of multiple DC / AC converters 11, wherein the first input end of the DC / AC converter 11 at this stage in the series circuit is connected to the second input end of the DC / AC converter 11 at the upper stage, the second input end of the DC / AC converter 11 at this stage in the series circuit is connected to the first input end of the DC / AC converter 11 at the lower stage, the first input end of the DC / AC converter 11 at the first stage in the series circuit is connected to the positive pole of the high-voltage direct current, the second input end of the DC / AC converter 11 at the last stage in the series circuit is connected to the negative pole of the high-voltage direct current, and the first output end and the second output end of each DC / AC converter 11 in the series circuit are respectively connected to the two ends of a primary winding of the multi-winding transformer 2.

[0051] Specifically, Figure 3 As shown, the DC / AC module 1 can be composed of one or more DC / AC converters 11. When multiple DC / AC converters 11 are included, the P-terminal of the DC / AC converter #1 is connected to the positive pole of the high-voltage DC, the n-terminal of the DC / AC converter #1 is connected to the p-terminal of the DC / AC converter #2, the n-terminal of the DC / AC converter #2 is connected to the p-terminal of the DC / AC converter #3, and so on. The n-terminal of the DC / AC converter #5 is connected to the p-terminal of the DC / AC converter #N, and the n-terminal of the DC / AC converter #N is connected to the negative pole of the high-voltage DC.

[0052] It should be noted that the sum of the number of the DC / AC converters 11 and the number of the first AC / DC modules 3 and the second AC / DC modules 4 may be equal or unequal, and this is not limited herein.

[0053] In a specific embodiment, the DC / AC converter 11 and the second AC / DC module 4 both include: any one of a half-bridge converter and a full-bridge converter.

[0054] Specifically, the DC / AC converter 11 and the second AC / DC module 4 may be as follows: Figure 4(a) to Figure 4(g) As shown, Figure 4(a) to Figure 4(e) The circuit topology of FIG4(d) and FIG4(e) is a single-phase half-bridge converter, and the circuit topology of FIG4(d) and FIG4(e) is a three-level half-bridge converter. Figure 4(f) to Figure 4(g) The circuit topology is a single-phase full-bridge converter. It should be noted that Figure 4(a) to Figure 4(g) The circuit topologies shown are for example only and are not intended to be limiting.

[0055] In a specific embodiment, as shown in Figures 5(a) and 5(b), the first AC / DC module 3 is composed of a first AC / DC converter 31, a second AC / DC converter 32, a first capacitor C1, a second capacitor C2, and a third capacitor C3, wherein the positive input terminal and the negative input terminal of the first AC / DC converter 31 are connected to the two ends of a secondary winding of the multi-winding transformer 2, and the positive input terminal and the negative input terminal of the second AC / DC converter 32 are connected to the two ends of a secondary winding of the multi-winding transformer 2; the positive output terminal of the first AC / DC converter 31 is connected to the first end of the first capacitor C1 and the first end of the second capacitor C2, respectively. The negative output end of the first AC / DC converter 31 is respectively connected to the positive output end of the second AC / DC converter 32, the second end of the first capacitor C1, and the first end of the third capacitor C3; the negative output end of the second AC / DC converter 32 is respectively connected to the second end of the third capacitor C3 and the second end of the second capacitor C2; the first end and the second end of the second capacitor C2 are respectively connected to the positive and negative poles of the load power supply end of the corresponding voltage level, or the first end and the second end of the second capacitor C2 are respectively connected in parallel with the first end and the second end of the second capacitor C2 in the other first AC / DC module 3 that outputs the same level of voltage, and then connected to the positive and negative poles of the power supply end of the load.

[0056] Specifically, the full voltage adjustment range of the first AC / DC module 3 is the difference between the upper limit voltage and the lower limit voltage of the effective working voltage of the load. The first AC / DC converter 31 is used to finely adjust the output voltage in a wide power range. The first AC / DC converter 31 and the second AC / DC converter 32 are connected in series to power the load, that is, the sum of their output voltages is the power supply voltage of the load, and by adjusting the output voltages of the first AC / DC converter 31 and the second AC / DC converter 32, the output voltage range can be expanded to meet the effective working voltage range of the load to be powered.

[0057] In a specific embodiment, as shown in Figures 6(a) and 6(b), the first AC / DC module 3 is composed of a first AC / DC converter 31, a second AC / DC converter 32, a DC / DC converter 33, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and an inductor L, wherein the positive input terminal and the negative input terminal of the first AC / DC converter 31 are connected to the two ends of a secondary winding of the multi-winding transformer 2, and the positive input terminal and the negative input terminal of the second AC / DC converter 32 are connected to the two ends of a secondary winding of the multi-winding transformer 2; the positive output terminal of the first AC / DC converter 31 is respectively connected to the first end of the first capacitor C1 and the positive input terminal of the DC / DC converter 33, and the negative output terminal of the first AC / DC converter 31 is respectively connected to the second end of the first capacitor C1 and the DC / DC converter 3 3 is connected to the negative input terminal of the DC / DC converter 3; the positive output terminal of the DC / DC converter 33 is connected to the first end of the inductor L, and the negative output terminal of the DC / DC converter 33 is respectively connected to the first end of the fourth capacitor C4, the first end of the third capacitor C3, and the positive output terminal of the second AC / DC converter 32; the negative output terminal of the second AC / DC converter 32 is respectively connected to the second end of the third capacitor C3 and the second end of the second capacitor C2; the second end of the inductor L is connected to the second end of the fourth capacitor C4 and the first end of the second capacitor C2; the first end and the second end of the second capacitor C2 are respectively connected to the positive and negative electrodes of the load power supply terminal of the corresponding voltage level, or the first end and the second end of the second capacitor C2 are respectively connected in parallel with the first end and the second end of the second capacitor C2 in the first AC / DC module 3 that outputs the same level of voltage, and then connected to the positive and negative electrodes of the power supply terminal of the load.

[0058] Specifically, the full voltage adjustment range of the first AC / DC module 3 is the difference between the upper limit voltage and the lower limit voltage of the effective working voltage of the load. The first AC / DC converter 31 is used to finely adjust the output voltage in a wide power range. For example, if the effective working voltage range of the load is 450V to 500V, the first AC / DC converter 31 outputs a fixed 50V DC power, the voltage range of the DC / DC converter 33 output is 0 to 50V, and the second AC / DC converter 32 outputs a fixed 450V DC power. Then, the range of the power supply voltage output after the second AC / DC converter 32 and the DC / DC converter 33 are connected in series is 450V to 500V, thereby satisfying the effective working voltage range of the load to be powered.

[0059] In a specific embodiment, the output voltages of the first AC / DC converter 31 and the second AC / DC converter 32 are adjusted by the turns ratio of the windings of the multi-winding transformer 2 connected to the first AC / DC module 3 .

[0060] Specifically, the turns ratio of the windings of the multi-winding transformer 2 connected to the first AC / DC module 3 in the embodiment of the present invention can be fixed or variable. When the turns ratio is fixed, the supply voltage range can be adjusted by adjusting the turns of the two secondary windings or adjusting the duty cycle of the internal components of the DC / DC converter 33. When the turns ratio is variable, the supply voltage range can be adjusted by adjusting the turns of the three windings or adjusting the duty cycle of the internal components of the DC / DC converter 33, wherein the internal components are not limited to controllable switch components such as IGBT and MOSFET.

[0061] In a specific embodiment, the first AC / DC converter 31 and the second AC / DC converter 32 are any one of diode uncontrolled rectifiers, thyristor half-controlled rectifiers, PWM fully controlled rectifiers, and rectifiers implemented with synchronous rectification technology.

[0062] Specifically, the first AC / DC converter 31 and the second AC / DC converter 32 of the embodiment of the present invention can be rectifiers of the same type or different types. The types of rectifiers include: a diode uncontrolled rectifier in Figure 7(a), a thyristor half-controlled rectifier in Figure 7(b), a PWM fully-controlled rectifier in Figure 7(c), and a typical rectifier implemented by synchronous rectification technology in Figure 7(d), but these are only examples and are not intended to be limiting.

[0063] It should be noted that the fully-controlled switching device in the PWM fully-controlled rectifier of Figure 7(c) is only IGBT as an example, but it can also be other fully-controlled switching devices. The switching device in the typical rectifier implemented by synchronous rectification technology in Figure 7(d) is MOS tube as an example, but it can also be other controllable switching devices, which is not limited here.

[0064] In a specific embodiment, the DC / DC converter 33 is any one of a boost DC-DC converter, a buck DC-DC converter, a buck-boost DC-DC converter, and a DC-DC converter using synchronous rectification technology.

[0065] Specifically, the DC / DC converter 33 of the embodiment of the present invention can be a step-up DC-DC converter, i.e., a Boost converter, as shown in Figure 8(a), or can be a step-down DC-DC converter, i.e., a Buck converter, as shown in Figure 8(b), or can be a step-up / step-down DC-DC converter, i.e., a Buck-Boost converter, as shown in Figure 8(c), or can be a synchronous rectification DC-DC converter, as shown in Figure 8(d).

[0066] Specifically, the embodiment of the present invention adjusts the output voltage of the DC-DC converter by adjusting the duty cycle (or switching frequency) of the switching device in the DC-DC converter. Figure 8(a) to Figure 8(d) The circuits shown are all for illustrative purposes, and the DC / DC converter 33 may also be other converters having a DC-to-DC conversion function, such as a Cuk converter.

[0067] Example 2

[0068] An embodiment of the present invention provides a high-voltage direct current transformer system, comprising: two or more high-voltage direct current transformers of Embodiment 1.

[0069] Specifically, the input ends of all DC / AC modules 1 are connected in series: the first input end of the DC / AC module 1 at this stage is connected to the second input end of the DC / AC module 1 at the upper stage, the second input end of the DC / AC module 1 at this stage is connected to the first input end of the DC / AC module 1 at the lower stage, the first input end of the DC / AC module 1 at the first stage is connected to the positive pole of the high-voltage direct current, and the second input end of the DC / AC module 1 at the last stage is connected to the negative pole of the high-voltage direct current.

[0070] Specifically, the first output ends of the first AC / DC modules 3 outputting the same level of voltage are connected in parallel and connected to the positive pole of the corresponding load power supply end, and the second output ends of the first AC / DC modules 3 outputting the same level of voltage are connected in parallel and connected to the negative pole of the corresponding load power supply end.

[0071] Specifically, the first output end of the second AC / DC module 4 outputting the same level of voltage is connected to the positive pole of the same common DC bus, and the second output end of the second AC / DC module 4 outputting the same level of voltage is connected to the negative pole of the same common DC bus.

[0072] Now as Fig. 9 Taking the high-voltage direct current multi-port conversion system shown as an example, the high-voltage direct current multi-port conversion system includes a high-voltage direct current multi-port conversion device #1 to a high-voltage direct current multi-port conversion device #N, the high-voltage direct current multi-port conversion device #1 includes a DC / AC converter #11 to a DC / AC converter #1n, a first AC / DC module #11 to a first AC / DC module #1k, and a second AC / DC module #11 to a second AC / DC module #1m, and the high-voltage direct current multi-port conversion device #nN includes a DC / AC converter #N1 to a DC / AC converter #Nn, a first AC / DC module #N1 to a first AC / DC module #Nk, and a second AC / DC module #N1 to a second AC / DC module #Nm.

[0073] It should be noted that the number of DC / AC converters 11 of each high-voltage DC multi-port conversion device can be equal or unequal, the number of first AC / DC modules 3 can be equal or unequal, and the number of second AC / DC modules 4 can be equal or unequal, and there is no limitation here.

[0074] Fig. 9 In the embodiment, the p-end of the DC / AC converter #11 of the high-voltage DC multi-port converter #1 is connected to the positive electrode of the high-voltage DC, the n-end of the DC / AC converter #11 is connected to the p-end of the DC / AC converter #12, the n-end of the DC / AC converter #12 is connected to the p-end of the DC / AC converter #13, and so on, the n-end of the DC / AC converter #1n-1 is connected to the p-end of the DC / AC converter #1n, the n-end of the DC / AC converter #1n is connected to the p-end of the DC / AC converter #21 of the high-voltage DC multi-port converter #2, and the DC / AC converter #21 is connected to the p-end of the DC / AC converter #22. The n-end of converter #21 is connected to the p-end of DC / AC converter #22, the n-end of DC / AC converter #22 is connected to the p-end of DC / AC converter #23, and so on, the n-end of DC / AC converter #2n-1 is connected to the p-end of DC / AC converter #2n, the n-end of DC / AC converter #2n is connected to the p-end of DC / AC converter #31 of high-voltage DC multi-port conversion device #3, and so on, the n-end of DC / AC #Nn-1 is connected to the p-end of DC / AC #N, and the n-end of DC / AC #Nn is connected to the negative pole of the high-voltage DC.

[0075] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A high voltage DC transformer, characterized in that: include: A DC / AC module, a multi-winding transformer, a first AC / DC module and / or a second AC / DC module, wherein the DC / AC module comprises a total input positive pole, a total input negative pole, and multiple groups of output terminals, wherein: The total input positive pole of the DC / AC module is connected to the positive pole of the high-voltage direct current, the total input negative pole of the DC / AC module is connected to the negative pole of the high-voltage direct current, each group of output ends of the DC / AC module is connected to two input ends of a primary winding of the multi-winding transformer, and the DC / AC module is used to convert high-voltage direct current into medium- and low-frequency alternating current; The first group of input ends of the first AC / DC module are connected to the two ends of one winding of the multi-winding transformer, the second group of input ends of the first AC / DC module are connected to the two ends of another winding of the multi-winding transformer, the first output end and the second output end of the first AC / DC module are respectively connected to the positive electrode and the negative electrode of the load power supply end of the corresponding voltage level, and the first AC / DC module is used to convert medium and low frequency alternating current into direct current to supply power to the load of the corresponding voltage level; The first AC / DC module is internally composed of one or more voltage converters, and the output voltage of the voltage converter is adjusted so that the output voltage range of the first AC / DC module is the difference between the upper limit voltage and the lower limit voltage of the load effective working voltage; The first input terminal and the second input terminal of the second AC / DC module are respectively connected to the first output terminal and the second output terminal of a secondary winding of the multi-winding transformer, and the first output terminal and the second output terminal of the second AC / DC are respectively connected to the positive electrode and the negative electrode of a public DC bus of a corresponding voltage level, and the second AC / DC module is used to convert medium and low frequency AC power into DC power to supply power to the public DC bus of the corresponding voltage level; The first AC / DC module is composed of a first AC / DC converter, a second AC / DC converter, a DC / DC converter, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor and an inductor, wherein the positive input terminal and the negative input terminal of the first AC / DC converter are connected to the two ends of a secondary winding of the multi-winding transformer, and the positive input terminal and the negative input terminal of the second AC / DC converter are connected to the two ends of a secondary winding of the multi-winding transformer; the positive output terminal of the first AC / DC converter is respectively connected to the first end of the first capacitor and the positive input terminal of the DC / DC converter, and the negative output terminal of the first AC / DC converter is respectively connected to the second end of the first capacitor and the negative input terminal of the DC / DC converter; the DC / DC converter The positive output end of the converter is connected to the first end of the inductor, and the negative output end of the DC / DC converter is respectively connected to the first end of the fourth capacitor, the first end of the third capacitor, and the positive output end of the second AC / DC converter; the negative output end of the second AC / DC converter is respectively connected to the second end of the third capacitor and the second end of the second capacitor; the second end of the inductor is connected to the second end of the fourth capacitor and the first end of the second capacitor; the first end and the second end of the second capacitor are respectively connected to the positive and negative poles of the load power supply end of the corresponding voltage level, or the first end and the second end of the second capacitor are respectively connected in parallel with the first end and the second end of the second capacitor in the first AC / DC module that outputs the same level of voltage, and then connected to the positive and negative poles of the power supply end of the load.

2. The high voltage DC transformer according to claim 1, characterized in that: When there are two or more first AC / DC modules, two output terminals of the first AC / DC modules that output the same level of voltage are connected in parallel and then connected to the positive and negative terminals of the power supply terminal of the load respectively.

3. The high voltage DC transformer according to claim 1, characterized in that: The DC / AC module is a series circuit consisting of multiple DC / AC converters, wherein: The first input end of the DC / AC converter at this stage in the series circuit is connected to the second input end of the DC / AC converter at the upper stage, the second input end of the DC / AC converter at this stage in the series circuit is connected to the first input end of the DC / AC converter at the lower stage, the first input end of the DC / AC converter at the first stage in the series circuit is connected to the positive pole of the high-voltage DC, the second input end of the DC / AC converter at the last stage in the series circuit is connected to the negative pole of the high-voltage DC, and the first output end and the second output end of each DC / AC converter in the series circuit are respectively connected to the two ends of a primary winding of the multi-winding transformer.

4. The high voltage DC transformer according to claim 3, characterized in that: The DC / AC converter and the second AC / DC module both include: any one of a half-bridge converter and a full-bridge converter.

5. The high voltage DC transformer according to claim 1, characterized in that: The first AC / DC converter and the second AC / DC converter are any one of a diode uncontrolled rectifier, a thyristor half-controlled rectifier, a PWM fully-controlled rectifier, and a rectifier implemented with synchronous rectification technology.

6. The high voltage DC transformer according to claim 1, characterized in that: The DC / DC converter is any one of a boost DC-DC converter, a buck DC-DC converter, a buck-boost DC-DC converter, and a DC-DC converter using synchronous rectification technology.

7. A high voltage direct current transformer system, characterized in that: include: Two or more high-voltage direct current transformers according to any one of claims 1 to 6, wherein: The input terminals of all DC / AC modules are connected in series: the first input terminal of the DC / AC module of this stage is connected to the second input terminal of the DC / AC module of the upper stage, the second input terminal of the DC / AC module of this stage is connected to the first input terminal of the DC / AC module of the lower stage, the first input terminal of the DC / AC module of the first stage is connected to the positive pole of the high-voltage direct current, and the second input terminal of the DC / AC module of the last stage is connected to the negative pole of the high-voltage direct current; The first output ends of the first AC / DC modules that output the same level of voltage are connected in parallel and then connected to the positive pole of the corresponding load power supply end, and the second output ends of the first AC / DC modules that output the same level of voltage are connected in parallel and then connected to the negative pole of the corresponding load power supply end; The first output end of the second AC / DC module that outputs the same level of voltage is connected to the positive pole of the same common DC bus, and the second output end of the second AC / DC that outputs the same level of voltage is connected to the negative pole of the same common DC bus.

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