Power supply module and modularized power supply

Abstract

The invention discloses a power supply module and a modular power supply. The power supply module comprises a multi-winding high-frequency transformer, a power frequency rectifier, a high-frequency converter, a diode rectifier bridge, an LC branch, a direct-current interface circuit and an equalization interface circuit, the first part is connected with a primary side high-frequency converter through an LC branch, the primary side high-frequency converter is connected with a power frequency rectifier, and the output of the power frequency rectifier forms an alternating current port; the second part is connected with a secondary side rectifier bridge through an LC branch, the secondary side rectifier bridge is connected with a direct-current interface circuit, and the output of the direct-current interface circuit forms a total direct-current port; and the third part is connected with the equalization interface circuit through an LC branch to form an equalization port. The size and the weight of the magnetic element are greatly reduced, and the power density of equipment is improved; a resonance technology is introduced to reduce switching loss and improve system efficiency; in addition, a three-phase four-wire alternating current port is constructed by matching with an independent AC accessory, and multi-type multifunctional electrical interfaces are provided.

Description

Technical Field

[0001] The invention relates to the technical field of power electronic electric energy conversion, and in particular to a power supply module and a modular power supply. Background Art

[0002] In recent years, the scale of the data center industry has continued to expand, the number and scale of data centers have continued to increase, and the proportion of land occupation and energy consumption costs in the operating costs of data centers has gradually increased. How to reduce the floor space and energy consumption of data center computer rooms has become an urgent problem to be solved in this field. Common power supply solutions for data centers at this stage include uninterruptible power supply (UPS), high-voltage DC system power supply, Panama power supply, etc. Traditional UPS and HVDC solutions have many power conversion links, and have problems such as low efficiency, large floor space, poor flexibility and scalability; Panama power supply saves many power conversion links compared to the previous two generations of solutions, and has certain advantages in reducing energy consumption, but it uses an industrial frequency transformer. Due to the low operating frequency and huge magnetic core volume and weight, the power density of the entire device is severely limited. In addition, none of the above power supply solutions can provide a three-phase four-wire AC interface to meet the power needs of lighting systems, air conditioning systems, maintenance systems and other systems, and need to be equipped with auxiliary equipment distribution cabinets, which increases the power supply cost.

[0003] The electric vehicle industry has achieved rapid development in recent years with its environmental advantages, and has driven the continuous upgrading of the electric vehicle industry. New electric vehicles have higher mileage and larger battery capacity, and require faster charging speeds. However, the charging infrastructure supporting the electric vehicle industry generally has disadvantages such as complex structure, simple functions, high cost, and low efficiency. At present, electric vehicle charging stations are mainly divided into AC connection systems and DC connection systems. The AC connection system reduces the voltage of the medium-voltage distribution network through the power frequency transformer, and then connects multiple AD / DC and DC / DC cascade converters to the AC bus on the secondary side of the transformer. This structure makes it have multiple conversion levels from the distribution network to the DC port, which increases the complexity and cost of the system and reduces the system efficiency; the DC connection system connects the AD / DC converter on the secondary side of the power frequency transformer to construct the DC bus. Compared with the AC connection system, the AD / DC conversion stage of the cascade converter is removed, which improves the system efficiency to a certain extent. However, the power frequency transformer and more isolation transformers lead to low system power density, complex system structure, and low reliability, and it is impossible to provide an AC port to meet the charging needs of electric vehicles equipped with on-board chargers.

[0004] In summary, in fields such as data centers and electric vehicles, power supplies based on power electronic transformers generally have common problems such as low efficiency, low power density, and few port types. Summary of the invention

[0005] In order to overcome the defects of the above-mentioned prior art, the present invention provides a power supply module and a modular power supply, which adopts a multi-winding high-frequency transformer to replace the traditional industrial frequency transformer or multiple two-winding transformers, greatly reducing the volume and weight of magnetic components and improving the power density of the equipment; at the same time, the resonance technology is introduced to reduce the switching loss and improve the system efficiency; and an independent AC accessory is used to construct a three-phase four-wire AC port to provide a multi-type and multi-functional electrical interface.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A power module includes a multi-winding high-frequency transformer, an industrial frequency rectifier, a high-frequency converter, a secondary-side rectifier bridge, an LC branch, a DC interface circuit, and a balanced interface circuit;

[0008] The total number of windings n of the multi-winding high-frequency transformer is divided into the following three parts according to the port configuration type:

[0009] The first part is connected to the primary side high frequency converter through the LC branch, the primary side high frequency converter is connected to the power frequency rectifier, and the power frequency rectifier output constitutes an AC port;

[0010] The second part is connected to the secondary side rectifier bridge through the LC branch, the secondary side rectifier bridge is connected to the DC interface circuit, and the output of the DC interface circuit constitutes a DC port;

[0011] The third part is connected to the balanced interface circuit through an LC branch to form a balanced port.

[0012] The total number of windings of the multi-winding high-frequency transformer is n=n1+n2+n3; the frequency of the multi-winding high-frequency transformer is any frequency in the range of several hundred hertz to several hundred kilohertz.

[0013] Among the n1≥≥0 windings of the first part of the multi-winding high-frequency transformer, one terminal of each winding is connected to one terminal of an LC branch, the other terminal of the LC branch is connected to the positive terminal of the output side of the primary-side high-frequency converter, the negative terminal of the output side of the primary-side high-frequency converter is connected to the other terminal of the winding, the positive and negative terminals of the input side of the primary-side high-frequency converter are respectively connected to the positive and negative terminals of the input side of the power frequency rectifier, and the positive and negative terminals of the output side of the power frequency rectifier constitute an AC port;

[0014] Among the n2≥≥0 windings of the second part of the multi-winding high-frequency transformer, one terminal of each winding is connected to one terminal of an LC branch, the other terminal of the LC branch is connected to the positive terminal on the output side of the secondary-side rectifier bridge, the negative terminal on the output side of the secondary-side rectifier bridge is connected to the other terminal of the winding, the positive and negative terminals on the input side of the secondary-side rectifier bridge are respectively connected to the positive and negative terminals on the input side of the DC interface circuit, the positive and negative terminals on the output side of the DC interface circuit constitute a DC port, and the n2 DC ports can be sequentially connected in parallel to constitute a total DC port;

[0015] Among the n3≥≥0 windings of the third part of the multi-winding high-frequency transformer, one terminal of each winding is connected to one terminal of an LC branch, the other terminal of the LC branch is connected to the positive terminal on the output side of the balancing interface circuit, the negative terminal on the output side of the balancing interface circuit is connected to the other terminal of the winding, and the positive and negative terminals on the input side of the balancing interface circuit are led out to form a balancing port.

[0016] The industrial frequency rectifier is a single-phase full-bridge circuit; the primary-side high-frequency converter is a single-phase full-bridge circuit or is replaced by a single-phase half-bridge, and the number of levels is two-level, three-level or multi-level; the DC interface circuit is a Buck circuit or is replaced by a direct-connected wire or other DC / DC converter; the balancing interface circuit is a single-phase full-bridge circuit or is replaced by a direct-connected wire, a three-phase inverter or a single-phase half-bridge, and the number of levels is two-level, three-level or multi-level.

[0017] The secondary side rectifier bridge is a diode uncontrolled rectifier bridge or a fully controlled rectifier bridge;

[0018] When applied to power supply of data center, power only flows from AC port to DC port in one direction. Diode has unidirectional conduction characteristic, and the secondary rectifier bridge is an uncontrolled rectifier bridge composed of diodes, thus reducing cost.

[0019] When used for charging electric vehicles, power flows bidirectionally between the AC port and the DC port. The secondary-side rectifier bridge needs to have bidirectional current-carrying capability and is designed as a fully-controlled rectifier bridge composed of fully-controlled power switch tubes.

[0020] The LC branch is an LC series resonant branch, and the inductance in the LC branch is the leakage inductance of the transformer winding or the sum of the leakage inductance and the external series inductance.

[0021] The single-phase full-bridge circuit includes four power switch tubes S1, S2, S3 and S4. The power switch tubes S1 and S2, S3 and S4 are respectively connected in series to form two half-bridges. The DC positive and negative terminals of the two half-bridges are respectively connected in parallel to form the positive and negative terminals on the input side. The midpoints of the two half-bridges are respectively led out to form the positive and negative terminals on the output side.

[0022] The diode uncontrolled rectifier bridge includes four power diodes D1, D2, D3 and D4. The power diodes D1 and D2, D3 and D4 are respectively connected in series to form two diode half-bridges. The DC positive and negative terminals of the two diode half-bridges are respectively connected in parallel to form the positive and negative terminals on the input side. The midpoints of the two diode half-bridges are respectively led out to form the positive and negative terminals on the output side.

[0023] The Buck circuit includes two power switch tubes Q1 and Q2 and an LC filter. The power switch tubes Q1 and Q2 are connected in series to form a half bridge. The DC positive and negative terminals of the half bridge constitute the positive and negative terminals on the input side. The midpoint of the half bridge is connected to the LC filter to form the positive and negative terminals on the output side.

[0024] The power switch tubes of the industrial frequency rectifier, primary-side high-frequency converter, secondary-side rectifier bridge, DC interface circuit, and balanced interface circuit are one of diodes, silicon-based MOSFETs, silicon-based IGBTs, silicon carbide-based MOSFETs, silicon carbide-based IGBTs, or gallium nitride-based FETs.

[0025] The DC ports derived from the DC interface circuit are connected in parallel to form multiple interleaved parallel Buck circuits. Carrier phase shift control is adopted to control the phase difference of each Buck circuit to cancel out the ripples of the output current, thereby increasing the equivalent switching frequency, reducing the current ripple, and thus reducing the volume of the inductor. According to the technical requirements of the power module application field, the DC interface circuit works in a voltage regulation mode or a current regulation mode;

[0026] When used for power supply in data centers, the output voltage does not need to be actively controlled, and the DC interface circuit achieves precise power control by controlling the output current. When used for charging electric vehicles, the DC interface circuit achieves constant voltage charging or constant current charging by controlling the output voltage or output current.

[0027] When the balancing interface circuits are respectively a direct-connected wire, a single-phase half-bridge or full-bridge circuit and a three-phase inverter, the composition of the balancing port is divided into the following three cases;

[0028] When the balancing interface circuit is a direct-connected wire, the balancing port is a single-phase AC balancing port;

[0029] When the balancing interface circuit is a single-phase half-bridge or full-bridge circuit, the balancing port is a DC balancing port;

[0030] When the balancing interface circuit is a three-phase inverter, the balancing port is a three-phase four-wire balancing port;

[0031] A modular power supply, comprising one or more power modules as described above; the AC input port and DC output port of each power module are connected in series and in parallel respectively; the modular power supply is boosted or expanded; the modular power supply has a three-phase AC port, a DC port and a balancing port; the modular power supply is connected to an AC accessory circuit to provide a three-phase four-wire port.

[0032] The AC accessory circuit includes a DC input type AC accessory circuit and an AC input type AC accessory circuit;

[0033] The DC input type AC accessory circuit is composed of four single-phase half-bridge circuits and a three-phase LC filter circuit. The positive and negative terminals on the input side of the four single-phase half-bridges are respectively connected in parallel and led out to form the positive and negative terminals on the DC input side. The midpoints of the three bridge arms are respectively connected to the LC filter circuit and then led out to form the three-phase AC output terminals. The midpoint of the fourth bridge arm is connected to the common end of the capacitor in the three-phase LC filter circuit and led out as the neutral line output terminal.

[0034] The AC input type AC accessory circuit is formed by six single-phase half-bridge circuits connected in parallel, and the positive and negative terminals on the input side of the six single-phase half-bridges are connected in parallel respectively, wherein the midpoints of the 1st and 2nd bridge arms are respectively led out to form the single-phase AC input positive and negative terminals, the midpoints of the 3rd, 4th and 5th bridge arms are respectively connected to the three-phase LC filter circuit and then led out to form the three-phase AC output terminal, and the midpoint of the bridge arm 6 is connected to the common end of the capacitor in the three-phase LC filter circuit and led out as the neutral line output terminal.

[0035] The connection method of the three-phase AC port of the modular power supply includes:

[0036] The AC input port of each power module forms a three-phase circuit, and each module forms A0≥(A 0+ ,A 0- ≥) port’s positive and negative terminals are connected in series between modules to form an A-phase circuit; each module forms B0(B 0+ ,B 0- ) port are connected in series between modules to form a B-phase circuit; each module forms C0 (C 0+ ,C 0- The positive and negative terminals of the A, B, and C phase circuits are connected in series between the modules to form a neutral point N.

[0037] The modular power supply DC port configuration includes:

[0038] The DC ports (h0, l0) of each power module are connected in parallel to each other to form the total DC port (h, l) of the modular power supply;

[0039] The power module balancing port configuration includes:

[0040] When the balanced port of the power module is a single-phase AC balanced port, the single-phase AC balanced ports of the k modules constituting the modular power supply are connected in parallel to form a common high-frequency AC bus. At this time, the positive and negative terminals on the input side of the AC input type AC accessory circuit can be connected to the common high-frequency AC bus, and the output side terminals of the AC accessory lead out a three-phase four-wire port;

[0041] When the balancing port of the power module is a DC balancing port, the DC balancing ports of the k modules constituting the modular power supply are connected in parallel to form a common DC bus. At this time, the positive and negative terminals on the input side of the DC input type AC accessory circuit can be connected to the common DC bus, and the output side terminals of the AC accessory lead out a three-phase four-wire port;

[0042] When the balancing port of the power module is a three-phase four-wire AC balancing port, the three-phase four-wire AC balancing ports of the k modules constituting the modular power supply are connected in parallel to form a common three-phase four-wire AC bus. At this time, there is no need to connect the AC accessory circuit, and the three-phase four-wire terminal can be directly led out;

[0043] The common high-frequency AC bus, the common DC bus, and the common three-phase four-wire AC bus can achieve a spontaneously balanced power flow and realize a self-balance of the DC capacitor voltage in each module.

[0044] The three-phase four-wire port has different functions according to the application field of the modular power supply. When used for power supply of data center, the three-phase four-wire port supplies power for lighting system, air conditioning system, maintenance system and other systems; when used for charging electric vehicles, the three-phase four-wire port meets the charging needs of electric vehicles equipped with on-board chargers, realizing AC / DC integrated charging.

[0045] Beneficial effects of the present invention:

[0046] (1) The modular power supply of the present invention adopts a multi-winding high-frequency transformer to replace the traditional industrial frequency transformer or multiple two-winding transformers, so that it has a smaller volume and weight, greatly reduces the volume and weight of magnetic components, and improves the power density of the equipment.

[0047] (2) The modular power supply of the present invention integrates multi-stage power conversion equipment into one device, thereby avoiding line losses between the multi-stage equipment. At the same time, the resonance technology is introduced to ensure that the quasi-sinusoidal current of the winding is almost in phase with the square wave voltage, so that the switching devices in the high-frequency converter bear very small current stress when turning on and off, and even when working at a higher switching frequency, it still produces smaller turn-on and turn-off losses, thereby improving the system efficiency.

[0048] (3) The modular power supply of the present invention can be used for both power supply of data centers and charging of electric vehicles. The number of windings n2 constituting the DC port can be set according to specific circumstances, and the DC interface circuit can operate in a voltage regulation mode or a current regulation mode, so that the DC port meets the technical requirements of different application fields and has high practicality and flexibility.

[0049] (4) The modular power supply of the present invention has a variety of electrical interfaces and more functions. The public AC bus or DC bus can be connected to compatible AC accessories, providing a three-phase four-wire port with different functions in different application fields. When used for power supply in data centers, the three-phase four-wire port can power lighting systems, air-conditioning systems, maintenance systems and other systems without the need for additional auxiliary equipment distribution cabinets, thereby reducing power supply costs; when used for charging electric vehicles, the three-phase four-wire port can meet the charging needs of electric vehicles equipped with on-board chargers, realizing AC / DC integrated charging.

[0050] (5) The fluctuating power between the three phases of the AC port of the modular power supply of the present invention can be partially or completely offset by the coupled transformer magnetic circuit to significantly reduce the capacitance of the DC side capacitor in the module for buffering the fluctuating power, and then the traditional electrolytic capacitor can be replaced by a film capacitor, which not only reduces the volume and weight but also overcomes the defects in life. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a structural schematic diagram of the power module of the present invention.

[0052] Figure 2 It is a schematic diagram of the structure of the AC accessories of the modular power supply of the present invention.

[0053] Figure 3 It is a schematic diagram of the structure of the three-phase AC port and the DC port of the modular power supply of the present invention.

[0054] Figure 4 It is a schematic diagram of the balanced busbar structure and AC accessories connection of the modular power supply of the present invention.

[0055] Figure 5 It is a schematic diagram of the modular power supply structure of an embodiment of the present invention.

[0056] Figure 6 It is a simulation waveform diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0057] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0058] like Figure 1As shown, a power supply module includes a multi-winding high-frequency transformer, an industrial frequency rectifier, a high-frequency converter, a diode rectifier bridge, an LC branch, a DC interface circuit and a balanced interface circuit;

[0059] The total number of windings n of the multi-winding high-frequency transformer is divided into the following three parts according to the port configuration type:

[0060] The first part is connected to the primary side high frequency converter through the LC branch, the primary side high frequency converter is connected to the power frequency rectifier, and the power frequency rectifier output constitutes an AC port;

[0061] The second part is connected to the secondary side rectifier bridge through the LC branch, the secondary side rectifier bridge is connected to the DC interface circuit, and the output of the DC interface circuit constitutes a DC port;

[0062] The third part is connected to the balanced interface circuit through an LC branch to form a balanced port.

[0063] In the n1≥0 windings of the multi-winding high-frequency transformer, one terminal of each winding is connected to one terminal of an LC branch, the other terminal of the LC branch is connected to the positive terminal on the output side of the primary-side high-frequency converter, the negative terminal on the output side of the primary-side high-frequency converter is connected to the other terminal of the winding, the positive and negative terminals on the input side of the primary-side high-frequency converter are respectively connected to the positive and negative terminals on the input side of the power frequency rectifier, and the positive and negative terminals on the output side of the power frequency rectifier constitute an AC port;

[0064] In the n2≥0 windings of the multi-winding high-frequency transformer, one terminal of each winding is connected to one terminal of an LC branch, the other terminal of the LC branch is connected to the positive terminal on the output side of the secondary-side rectifier bridge, the negative terminal on the output side of the secondary-side rectifier bridge is connected to the other terminal of the winding, the positive and negative terminals on the input side of the secondary-side rectifier bridge are respectively connected to the positive and negative terminals on the input side of the DC interface circuit, the positive and negative terminals on the output side of the DC interface circuit constitute a DC port, and the n2 DC ports can be sequentially connected in parallel to constitute a total DC port;

[0065] In the n3≥0 windings of the multi-winding high-frequency transformer, one terminal of each winding is connected to one terminal of an LC branch, the other terminal of the LC branch is connected to the output side positive terminal of the balancing interface circuit, the output side negative terminal of the balancing interface circuit is connected to the other terminal of the winding, and the input side positive and negative terminals of the balancing interface circuit are led out to form a balancing port.

[0066] The total winding n of the multi-winding high-frequency transformer is n1+n2+n3; the frequency of the multi-winding high-frequency transformer is any frequency in the range of several hundred hertz to several hundred kilohertz.

[0067] The industrial frequency rectifier is a single-phase full-bridge circuit; the primary-side high-frequency converter is a full-bridge circuit, which can be replaced by a single-phase half-bridge, and the number of levels can be two-level, three-level or multi-level; the DC interface circuit is a Buck circuit, which can be replaced by a direct-connected wire or other DC / DC converters; the balancing interface circuit is a full-bridge circuit, which can be replaced by a direct-connected wire, a three-phase inverter or a single-phase half-bridge, and the number of levels is two-level, three-level or multi-level.

[0068] The secondary side rectifier bridge is designed as a diode or a fully controlled tube according to the technical requirements of the power module application field. For example, when applied to data center power supply, power only flows from the AC port to the DC port in one direction. The diode has a unidirectional conduction characteristic, so the secondary side rectifier bridge can be designed as follows: Figure 1 (b) shows an uncontrolled rectifier bridge composed of diodes, thereby reducing costs; when used for charging electric vehicles, power flows bidirectionally between the AC port and the DC port, and the secondary side rectifier bridge needs to have bidirectional current flow capability, so it needs to be designed as follows Figure 1 (c)(d) shows a fully controlled rectifier bridge composed of fully controlled power switching tubes.

[0069] The LC branch is an LC series resonant branch, and the inductance in the LC branch is the leakage inductance of the transformer winding or the sum of the leakage inductance and the external series inductance.

[0070] The single-phase full-bridge circuit includes four power switch tubes S1, S2, S3 and S4. The power switch tubes S1 and S2, S3 and S4 are respectively connected in series to form two half-bridges. The DC positive and negative terminals of the two half-bridges are respectively connected in parallel to form the positive and negative terminals on the input side. The midpoints of the two half-bridges are respectively led out to form the positive and negative terminals on the output side.

[0071] The diode uncontrolled rectifier bridge includes four power diodes D1, D2, D3 and D4. The power diodes D1 and D2, D3 and D4 are respectively connected in series to form two diode half-bridges. The DC positive and negative terminals of the two diode half-bridges are respectively connected in parallel to form the positive and negative terminals on the input side. The midpoints of the two diode half-bridges are respectively led out to form the positive and negative terminals on the output side.

[0072] The Buck circuit includes two power switch tubes Q1 and Q2 and an LC filter. The power switch tubes Q1 and Q2 are connected in series to form a half bridge. The DC positive and negative terminals of the half bridge constitute the positive and negative terminals on the input side. The midpoint of the half bridge is connected to the LC filter to form the positive and negative terminals on the output side.

[0073] The power switch tubes of the industrial frequency rectifier, primary-side high-frequency converter, secondary-side rectifier bridge, DC interface circuit, and balanced interface circuit are one of diodes, silicon-based MOSFETs, silicon-based IGBTs, silicon carbide-based MOSFETs, silicon carbide-based IGBTs, or gallium nitride-based FETs.

[0074] The number of windings n2 constituting the DC port of the power module is determined by the technical requirements of the power module application field, the module rated power, and the withstand voltage and current of the switching device, and can be flexibly set according to the specific situation. The following examples specifically illustrate the selection basis.

[0075] (1) When the power module is used for power supply in a data center, the input is required to be three-phase AC, so the number of windings constituting the AC port is n1=3; the rated power of the module is 80kW, the output DC voltage is required to be 200V~280V, the DC side voltage of the diode rectifier bridge is 300V, and the switch tube model IPW65R018CFD7 (650V / 106A) produced by Infineon is selected. Due to the current carrying capacity limitation of the switch tube, n2=6 windings are required to constitute the DC port connected in parallel for current shunting; the power module also needs n3≥=1 balancing port connected to the balancing port of other modules to achieve self-balancing of power and capacitor voltage of multiple power modules. At this time, the total number of windings is n=10.

[0076] (2) When the power module is used for charging electric vehicles, the input is required to be three-phase AC, so the number of windings constituting the AC port is n1=3; in order to ensure compatibility with various electric vehicle batteries, the output DC voltage is required to be 200V~850V, the module power is 80kW, the DC side voltage of the diode rectifier bridge is 850V, and the switch tube model IDWD100E120D7 (1200V / 100A) produced by Infineon is selected. Due to the current carrying capacity limitation of the switch tube, n2=3 windings are required to constitute the DC port and be connected in parallel for current shunting; the power module also needs n3≥=1 balancing port connected to the balancing port of other modules to achieve self-balancing of power and capacitor voltage of multiple power modules. At this time, the total number of windings is n=7.

[0077] The DC ports derived from the DC interface circuit are connected in parallel to form a multiple interlaced parallel Buck circuit, which uses carrier phase shift control to control the phase difference of each Buck circuit to cancel out the ripples of the output current, thereby increasing the equivalent switching frequency, reducing the current ripple, and thus reducing the volume of the inductor. According to the technical requirements of the power module application field, the DC interface circuit can operate in a voltage regulation mode or a current regulation mode. For example, when applied to power supply in a data center, the output voltage does not need to be actively controlled, and the DC interface circuit achieves precise power control by controlling the output current; when applied to charging electric vehicles, the DC interface circuit achieves constant voltage charging or constant current charging by controlling the output voltage or output current.

[0078] When the balancing interface circuits are respectively a direct-connected wire, a single-phase half-bridge or full-bridge circuit and a three-phase inverter, the composition of the balancing port is divided into the following three cases;

[0079] When the balancing interface circuit is a direct-connected wire, the balancing port is a single-phase AC balancing port;

[0080] When the balancing interface circuit is a single-phase half-bridge or full-bridge circuit, the balancing port is a DC balancing port;

[0081] When the balancing interface circuit is a three-phase inverter, the balancing port is a three-phase four-wire balancing port.

[0082] A modular power supply comprises one or more power modules as described above; the AC input port and DC output port of each power module are respectively connected in series and in parallel to realize the boosting or capacity expansion of the modular power supply; the modular power supply has a three-phase AC port, a DC port and a balancing port; the modular power supply can be connected to an AC accessory circuit to provide a three-phase four-wire port.

[0083] like Figure 2 The AC accessory circuit shown includes a DC input type AC accessory circuit and an AC input type AC accessory circuit; Figure 2 As shown in (a), the DC input type AC accessory circuit includes 8 power switch tubes S1, S2, S3, S4, S5, S6, S7, S8 and a three-phase LC filter circuit. The power switch tubes S1 and S2, S3 and S4, S5 and S6, S7 and S8 are connected in series to form 4 single-phase half-bridge circuits, and the DC positive and negative terminals of the 4 single-phase half-bridges are connected in parallel and respectively lead out to form the DC input side positive and negative terminals (H dc+ , H dc- ), where the midpoints of the three half-bridges are connected to the LC filter circuit and then lead out to form a three-phase AC output terminal (H a , H b , H c ), the midpoint of the fourth half bridge is connected to the common end of the capacitor in the three-phase LC filter circuit and is led out as the neutral line output terminal (H n ). DC input side positive and negative terminals (H dc+ , H dc- ) can be connected to the DC port or DC bus of the power module to invert DC into three-phase AC, and then lead out to the three-phase four-wire port after filtering.

[0084] like Figure 2 As shown in (b), the AC input type AC accessory circuit includes 12 power switch tubes S1, S2, S3, S4, S5, S6, S7, S8, S9, S 10 , S 11 , S 12 And three-phase LC filter circuit, power switch tube S1 and S2, S3 and S4, S5 and S6, S7 and S8, S9 and S 10 , S 11and S 12 Six single-phase half-bridge circuits are connected in series, and the DC positive and negative terminals of the six single-phase half-bridges are connected in parallel, respectively. The midpoints of the first and second half-bridges are respectively connected to form the single-phase AC input positive and negative terminals (G ac+ , G ac- ), the midpoints of the 3rd, 4th, and 5th half bridges are connected to the three-phase LC filter circuit and then lead out to form the three-phase AC output terminal (G a , G b , G c ), the midpoint of bridge arm 6 is connected to the common end of the capacitor in the three-phase LC filter circuit and is led out as the neutral line output terminal (G n ). Single-phase AC input positive and negative terminals (G ac+ , G ac- ≥) can be connected to the AC port or AC bus of the power module, rectify the AC to DC and then invert it to three-phase AC, and then lead out to the three-phase four-wire port after filtering.

[0085] like Figure 3 As shown, the connection method of the three-phase AC port of the modular power supply includes:

[0086] The AC input port of each power module forms a three-phase circuit, and each module forms A0≥(A 0+ ,A 0- ≥) port’s positive and negative terminals are connected in series between modules to form an A-phase circuit; each module forms B0(B 0+ ,B 0- ) port are connected in series between modules to form a B-phase circuit; each module forms C0 (c 0+ ,C 0- The positive and negative terminals of the ) port are connected in series between the modules to form a C-phase circuit; the negative terminals of the A, B, and C phase circuits are connected together to form a neutral point N; by connecting in series to divide the voltage, the three-phase AC port of the modular power supply is connected to a medium voltage or higher voltage level three-phase power grid, improving its practical application flexibility. ≥

[0087] The modular power supply DC port configuration includes:

[0088] The DC ports (h0, l0) of each power module are connected in parallel to form the total DC port (h, l) of the modular power supply. By connecting in parallel to perform current splitting, the modular power supply can more conveniently expand its capacity, and the DC port outputs higher power to meet different power requirements in actual applications.

[0089] The power module balancing port configuration includes:

[0090] like Figure 4As shown in (a), when the balanced port of the power module is a single-phase AC balanced port, the single-phase AC balanced ports of the k modules constituting the modular power supply are connected in parallel to form a common high-frequency AC bus. At this time, the positive and negative terminals on the input side of the AC input type AC accessory circuit can be connected to the common high-frequency AC bus, and the output side terminals of the AC accessory lead out a three-phase four-wire port;

[0091] like Figure 4 As shown in (b), when the balancing port of the power module is a DC balancing port, the DC balancing ports of the k modules constituting the modular power supply are connected in parallel to form a common DC bus. At this time, the positive and negative terminals on the input side of the DC input type AC accessory circuit can be connected to the common DC bus, and the output side terminals of the AC accessory lead out a three-phase four-wire port;

[0092] like Figure 4 As shown in (c), when the balancing port of the power module is a three-phase four-wire AC balancing port, the three-phase four-wire AC balancing ports of the k modules constituting the modular power supply are connected in parallel to form a common three-phase four-wire AC bus. At this time, there is no need to connect the AC accessory circuit, and the three-phase four-wire terminal can be directly led out;

[0093] The common high-frequency AC bus, the common DC bus, and the common three-phase four-wire AC bus can achieve a spontaneously balanced power flow and realize a self-balance of the DC capacitor voltage in each module.

[0094] The three-phase four-wire port has different functions according to the application field of the modular power supply. For example, when used for power supply in a data center, the three-phase four-wire port can power lighting systems, air-conditioning systems, maintenance systems and other systems; when used for charging electric vehicles, the three-phase four-wire port can meet the charging needs of electric vehicles equipped with on-board chargers, and realize AC / DC integrated charging. In summary, the power module of the present invention uses a multi-winding high-frequency transformer to replace the traditional industrial frequency transformer or multiple two-winding transformers, which greatly reduces the volume and weight of the magnetic components; at the same time, it introduces resonance technology, so that the power switching device still produces smaller turn-on and turn-off losses even when working at a higher switching frequency; and it has a variety of electrical interfaces and more functions. Figure 1As shown, the n1 windings in the multi-winding high-frequency transformer are used to construct an AC port. When connected to a three-phase AC power grid, the fluctuating power between the three phases can be partially or completely offset by the coupled transformer magnetic circuit to significantly reduce the capacitance of the DC side capacitor used to buffer the fluctuating power in the module; n2 windings are used to construct a DC port. The number of windings can be flexibly set according to the specific application field and work in different control modes, so that the modular power supply can be suitable for both data center power supply and electric vehicle charging; n3 windings are used to construct a balanced port. When one or more power modules are selected to construct a modular power supply according to the requirements of voltage and power level, the interconnection of the balanced ports can realize the self-balancing of power and capacitor voltage between modules. The common DC or AC busbar formed by the interconnection of the balanced ports can also be connected to a DC input type or AC input type AC accessory circuit to provide a three-phase four-wire port, which has different functions in different application fields. The power module and modular power supply of the present invention are intended to solve the common problems of low efficiency, low power density, and few port types commonly found in fields such as data center power supply and electric vehicle charging.

[0095] See also Figure 5 , Figure 5 It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0096] Specifically, Figure 5 As shown in (a), in a power module, the high-frequency transformer has ten windings, of which the three windings on the primary side form three AC ports A0 (A 0+ ,A 0- )、B0(B 0+ ,B 0- )、C0(C 0+ ,C 0- ); six windings on the secondary side form six DC ports and are connected in parallel to form the total DC port (h0, l0) of the power module; one winding on the secondary side forms a balanced port. The power frequency rectifier and high frequency converter are single-phase full-bridge circuits, the DC voltage regulation circuit is a Buck circuit, and the balanced interface circuit is a single-phase full-bridge circuit. The embodiment of the present invention is applied to power supply of a data center, so the secondary side rectifier bridge is a diode uncontrolled rectifier bridge.

[0097] Specifically, Figure 5 As shown in (b), the A0 (A 0+ ,A 0- ) port are connected in series between the modules to form an A-phase circuit; at the same time, the B0 (B 0+ ,B 0- )、C0(C 0+ ,C 0-) ports are connected in series between modules to form B-phase and C-phase circuits; the negative terminals of the A, B, and C-phase circuits are connected together to form a neutral point N. The DC ports (h0, l0) of the ten power modules are connected in parallel to form a total DC port (h, l). The balanced ports (dc+, dc-) of the ten power modules are connected in parallel to form a common DC bus. The three-phase AC ports (A, B, C) are each connected in series with an inductor and then connected to a three-phase medium-voltage AC source, and the DC ports (h, l) are connected to a DC load. The common DC bus of the modular power supply is connected to a DC input AC accessory, and the output side of the DC input AC accessory is connected to a three-phase four-wire load.

[0098] The simulation parameters of the modular power supply model designed in this embodiment are summarized in Table 1. Based on this, the modular power supply simulation model constructed by Matlab / Simulink achieves the expected design goals and realizes the control function. The simulation waveforms are summarized in Figure 6 middle.

[0099] Table 1≥Data center power supply simulation parameters

[0100]

[0101] Figure 6 : is a simulation waveform diagram of an embodiment of the present invention. Figure 6 As shown, (a) is the three-phase grid voltage waveform; (b) is the three-phase grid current waveform; (c) is the low-voltage DC output voltage waveform; (d) is the low-voltage DC output current waveform; (e) is the output power waveform; (f) is the A-phase voltage modulation waveform; (g) is the DC side capacitor voltage waveform; (h) is the three-phase four-wire port output voltage waveform.

[0102] When the simulation model is started normally, the output power is the rated power of 1MW, the three-phase grid voltage and current are in phase to ensure high power factor operation, and the output voltage is stable at 270VDC. At t = 0.2s, the output voltage drops to 220VDC, the Buck circuit works in the current regulation mode, the current of the DC port changes rapidly with the control command to maintain the rated output power, the three-phase grid current and DC capacitor voltage remain basically unchanged before and after the voltage drop, and the output voltage of the three-phase four-wire port is normal, proving that the modular power supply simulation model works normally and has good dynamic performance.

Claims

1. A power module, characterized in that: It includes a multi-winding high-frequency transformer, an industrial frequency rectifier, a high-frequency converter, a secondary-side rectifier bridge, an LC branch, a DC interface circuit and a balanced interface circuit; The total number of windings n of the multi-winding high-frequency transformer is divided into the following three parts according to the port configuration type: The first part is connected to the primary side high frequency converter through the LC branch, the primary side high frequency converter is connected to the power frequency rectifier, and the power frequency rectifier output constitutes an AC port; The second part is connected to the secondary side rectifier bridge through the LC branch, the secondary side rectifier bridge is connected to the DC interface circuit, and the output of the DC interface circuit constitutes a DC port; The third part is connected to the balanced interface circuit through an LC branch to form a balanced port.

2. A power module according to claim 1, characterized in that: The total number of windings of the multi-winding high-frequency transformer is n=n1+n2+n3; the frequency of the multi-winding high-frequency transformer is any frequency in the range of several hundred hertz to several hundred kilohertz.

3. A power module according to claim 2, characterized in that: Among the n1≥0 windings of the first part of the multi-winding high-frequency transformer, one terminal of each winding is connected to one terminal of an LC branch, the other terminal of the LC branch is connected to the positive terminal of the output side of the primary-side high-frequency converter, the negative terminal of the output side of the primary-side high-frequency converter is connected to the other terminal of the winding, the positive and negative terminals of the input side of the primary-side high-frequency converter are respectively connected to the positive and negative terminals of the input side of the power frequency rectifier, and the positive and negative terminals of the output side of the power frequency rectifier constitute an AC port; Among the n2≥0 windings of the second part of the multi-winding high-frequency transformer, one terminal of each winding is connected to one terminal of an LC branch, the other terminal of the LC branch is connected to the positive terminal on the output side of the secondary-side rectifier bridge, the negative terminal on the output side of the secondary-side rectifier bridge is connected to the other terminal of the winding, the positive and negative terminals on the input side of the secondary-side rectifier bridge are respectively connected to the positive and negative terminals on the input side of the DC interface circuit, the positive and negative terminals on the output side of the DC interface circuit constitute a DC port, and the n2 DC ports can be sequentially connected in parallel to constitute a total DC port; Among the n3≥0 windings of the third part of the multi-winding high-frequency transformer, one terminal of each winding is connected to one terminal of an LC branch, the other terminal of the LC branch is connected to the output side positive terminal of the balancing interface circuit, the output side negative terminal of the balancing interface circuit is connected to the other terminal of the winding, and the input side positive and negative terminals of the balancing interface circuit are led out to form a balancing port.

4. A power module according to claim 3, characterized in that: The secondary side rectifier bridge is a diode uncontrolled rectifier bridge or a fully controlled rectifier bridge; When applied to power supply of data center, power only flows from AC port to DC port in one direction, diode has unidirectional conduction characteristic, and the secondary side rectifier bridge is an uncontrolled rectifier bridge composed of diodes; When used for charging electric vehicles, power flows bidirectionally between the AC port and the DC port. The secondary-side rectifier bridge needs to have bidirectional current-carrying capability and is designed as a fully-controlled rectifier bridge composed of fully-controlled power switch tubes. The LC branch is an LC series resonant branch, and the inductance in the LC branch is the leakage inductance of the transformer winding or the sum of the leakage inductance and the external series inductance.

5. A power module according to claim 1, characterized in that: The industrial frequency rectifier is a single-phase full-bridge circuit; the primary-side high-frequency converter is a single-phase full-bridge circuit or is replaced by a single-phase half-bridge, and the number of levels is two-level, three-level or multi-level; the DC interface circuit is a Buck circuit or is replaced by a direct-connected wire or other DC / DC converter; the balancing interface circuit is a single-phase full-bridge circuit or is replaced by a direct-connected wire, a three-phase inverter or a single-phase half-bridge, and the number of levels is two-level, three-level or multi-level.

6. A power module according to claim 5, characterized in that: The single-phase full-bridge circuit comprises four power switch tubes S1, S2, S3 and S4, the power switch tubes S1 and S2, S3 and S4 are respectively connected in series to form two half-bridges, the DC positive and negative terminals of the two half-bridges are respectively connected in parallel to form the positive and negative terminals on the input side, and the midpoints of the two half-bridges are respectively led out to form the positive and negative terminals on the output side; The diode rectifier bridge comprises four power diodes D1, D2, D3 and D4, the power diodes D1 and D2, D3 and D4 are respectively connected in series to form two diode half-bridges, the DC positive and negative terminals of the two diode half-bridges are respectively connected in parallel to form the positive and negative terminals on the input side, and the midpoints of the two diode half-bridges are respectively led out to form the positive and negative terminals on the output side; The Buck circuit includes two power switch tubes Q1 and Q2 and an LC filter. The power switch tubes Q1 and Q2 are connected in series to form a half bridge. The DC positive and negative terminals of the half bridge constitute the positive and negative terminals on the input side. The midpoint of the half bridge is connected to the LC filter to form the positive and negative terminals on the output side. The power switch tubes of the industrial frequency rectifier, primary-side high-frequency converter, secondary-side rectifier bridge, DC interface circuit, and balanced interface circuit are one of diodes, silicon-based MOSFETs, silicon-based IGBTs, silicon carbide-based MOSFETs, silicon carbide-based IGBTs, or gallium nitride-based FETs.

7. A power module according to claim 1, characterized in that: The DC ports derived from the DC interface circuit are connected in parallel to form multiple interleaved parallel Buck circuits, and carrier phase shift control is adopted to control the phase difference of each Buck circuit to cancel out the ripples of the output current; the DC interface circuit works in a voltage regulation mode or a current regulation mode; When used in data center power supply, the output voltage does not need to be actively controlled, and the DC interface circuit achieves precise power control by controlling the output current; when used in electric vehicle charging, the DC interface circuit achieves constant voltage charging or constant current charging by controlling the output voltage or output current; When the balancing interface circuits are respectively a direct-connected wire, a single-phase half-bridge or full-bridge circuit and a three-phase inverter, the composition of the balancing port is divided into the following three cases; When the balancing interface circuit is a direct-connected wire, the balancing port is a single-phase AC balancing port; When the balancing interface circuit is a single-phase half-bridge or full-bridge circuit, the balancing port is a DC balancing port; When the balancing interface circuit is a three-phase inverter, the balancing port is a three-phase four-wire balancing port.

8. A modular power supply, comprising one or more power modules according to any one of claims 1 to 7; characterized in that: The AC input port and DC output port of each power module are connected in series and in parallel respectively; the modular power supply is boosted or expanded; the modular power supply has a three-phase AC port, a DC port and a balancing port; the modular power supply is connected to an AC accessory circuit to provide a three-phase four-wire port. The AC accessory circuit includes a DC input type AC accessory circuit and an AC input type AC accessory circuit: The DC input type AC accessory circuit is composed of four single-phase half-bridge circuits and a three-phase LC filter circuit. The positive and negative terminals on the input side of the four single-phase half-bridges are respectively connected in parallel and respectively led out to form the positive and negative terminals on the DC input side. The midpoints of the three bridge arms are respectively connected to the LC filter circuit and then led out to form the three-phase AC output terminal. The midpoint of the fourth bridge arm is connected to the common end of the capacitor in the three-phase LC filter circuit and led out as the neutral line output terminal. The AC input type AC accessory circuit is formed by six single-phase half-bridge circuits connected in parallel, and the positive and negative terminals on the input side of the six single-phase half-bridges are connected in parallel respectively, wherein the midpoints of the 1st and 2nd bridge arms are respectively led out to form the single-phase AC input positive and negative terminals, the midpoints of the 3rd, 4th and 5th bridge arms are respectively connected to the three-phase LC filter circuit and then led out to form the three-phase AC output terminal, and the midpoint of the bridge arm 6 is connected to the common end of the capacitor in the three-phase LC filter circuit and led out as the neutral line output terminal.

9. The power module according to claim 8, characterized in that: The connection method of the three-phase AC port of the modular power supply includes: The AC input port of each power module forms a three-phase circuit, and each module forms A0((A 0+ ,A 0- The positive and negative terminals of the () port are connected in series between the modules to form an A phase circuit; each module forms B0 (B 0+ ,B 0- ) port are connected in series between modules to form a B-phase circuit; each module forms C0 (C 0+ ,C 0- The positive and negative terminals of the A, B, and C phase circuits are connected in series between the modules to form a neutral point N. The modular power supply DC port configuration includes: The DC ports (h0, l0) of each power module are connected in parallel to each other to form the total DC port (h, l) of the modular power supply; The power module balancing port configuration includes: When the balanced port of the power module is a single-phase AC balanced port, the single-phase AC balanced ports of the k modules constituting the modular power supply are connected in parallel to form a common high-frequency AC bus. At this time, the positive and negative terminals on the input side of the AC input type AC accessory circuit can be connected to the common high-frequency AC bus, and the output side terminals of the AC accessory lead out a three-phase four-wire port; When the balancing port of the power module is a DC balancing port, the DC balancing ports of the k modules constituting the modular power supply are connected in parallel to form a common DC bus. At this time, the positive and negative terminals on the input side of the DC input type AC accessory circuit can be connected to the common DC bus, and the output side terminals of the AC accessory lead out a three-phase four-wire port; When the balancing port of the power module is a three-phase four-wire AC balancing port, the three-phase four-wire AC balancing ports of the k modules constituting the modular power supply are connected in parallel to form a common three-phase four-wire AC bus. At this time, there is no need to connect the AC accessory circuit, and the three-phase four-wire terminal can be directly led out; The common high-frequency AC bus, the common DC bus, and the common three-phase four-wire AC bus can achieve a spontaneously balanced power flow and realize a self-balance of the DC capacitor voltage in each module.

10. The power module according to claim 9, characterized in that: The three-phase four-wire port has different functions according to the application field of the modular power supply. When used for power supply of data center, the three-phase four-wire port supplies power for lighting system, air conditioning system, maintenance system and other systems; when used for charging electric vehicles, the three-phase four-wire port meets the charging needs of electric vehicles equipped with on-board chargers, realizing AC / DC integrated charging.

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