Power conversion apparatus and power conversion system

Abstract

A power conversion apparatus, comprising a plurality of three-phase power modules (11-1N), a switch matrix (20), and a controller (30). Each of the three-phase power modules (11-1N) comprises three single-phase alternating current-to-direct current conversion units (111, 112, 113), which respectively receive three-phase alternating current voltages of a three-phase alternating current power supply, and convert the three-phase alternating current voltages to provide a direct current. The switch matrix (20) receives the direct currents provided by the three-phase power modules (11-1N). The controller (30) provides a switch control signal to control the switch matrix (20) so as to determine output power provided by the direct currents. The present disclosure further relates to a power conversion system.

Description

Power conversion device and power conversion system Technical Field

[0001] This invention relates to a power conversion device and a power conversion system, and particularly to a power conversion device and a power conversion system with low-frequency ripple current suppression function. Background Technology

[0002] With the rise of environmental awareness and green energy consciousness, the sales of electric vehicles are increasing exponentially, leading to a greater demand for charging stations. Meeting the charging needs of electric vehicles, especially those requiring very light loads, and providing a balance between overall power efficiency and charging quality is a common goal for those skilled in the art.

[0003] Therefore, how to design a power conversion device and power conversion system to solve the problems and technical bottlenecks of the existing technology is an important research topic for the inventors of this disclosure. Summary of the Invention

[0004] One object of the present invention is to provide a power conversion device. The power conversion device includes a plurality of three-phase power modules, a switch matrix, and a controller. Each three-phase power module includes three single-phase AC-to-DC conversion units, which respectively receive the three-phase AC voltage from a three-phase AC power supply and convert the three-phase AC voltage to provide DC current. The switch matrix receives the DC current provided by the three-phase power modules. The controller provides switch control signals to control the switch matrix to determine the output power provided by the DC current.

[0005] Therefore, the power conversion device proposed in this invention has the following features and advantages: 1. Under light load conditions, in order to reduce the power supply of the power conversion device to meet the reduced power demand of the load, the three-phase power module can be controlled to shut down, so that the power conversion device outputs a balanced three-phase current to suppress the generation of ripple current; 2. Under light load conditions, in order to reduce the power supply of the power conversion device to meet the reduced power demand of the load, the alternating shutdown of the single-phase AC to DC conversion unit can be controlled, so that the power conversion device outputs a balanced three-phase current to suppress the generation of ripple current; 3. Through simple circuit design, the control of the low-frequency ripple current suppression circuit is realized, so that under extremely light load conditions, the system efficiency can be maintained and the ripple component of DC current can be eliminated, so that the output current flowing to the load is a DC current without ripple component.

[0006] Another object of the present invention is to provide a power conversion system. The power conversion system includes a plurality of power conversion devices and a system controller. Each power conversion device includes a plurality of three-phase power modules, a switch matrix, and a controller. Each three-phase power module includes three single-phase AC-to-DC conversion units, which respectively receive the three-phase AC voltage from a three-phase AC power supply and convert the three-phase AC voltage to provide DC current. The switch matrix receives the DC current provided by the three-phase power modules. The controller provides switch control signals to control the switch matrix to determine the output power provided by the DC current. The system controller is connected to the controllers of the power conversion devices and controls the controllers via communication to control the corresponding power conversion devices to output balanced output power.

[0007] Therefore, the power conversion system proposed in this invention has the following features and advantages: 1. Under light load conditions, in order to reduce the power supply to the power conversion device in response to the reduced load power demand, the three-phase power module can be shut down, so that the power conversion device outputs a balanced three-phase current to suppress the generation of ripple current; 2. Under light load conditions, in order to reduce the power supply to the power conversion device in response to the reduced load power demand, the alternating shutdown of the single-phase AC to DC conversion unit can be controlled, so that the power conversion device outputs a balanced three-phase current to suppress the generation of ripple current, and at the same time, the three-phase power supply at the grid end will not have the problem of uneven load withdrawal, thereby maintaining the power supply balance at the grid end; 3. Through simple circuit design, the control of the low-frequency ripple current suppression circuit is realized, so that under extremely light load conditions, the system efficiency can be maintained and the ripple component of DC current can be eliminated, so that the output current flowing to the load is a DC current without ripple component; 4. Through the system controller, multiple power conversion devices are integrated and controlled to achieve balanced output current across rack application areas to maintain the power supply balance at the grid end.

[0008] To gain a deeper understanding of the techniques, means, and effects employed by this invention to achieve its intended purpose, please refer to the following detailed description and accompanying drawings. It is believed that the purpose, features, and characteristics of this invention can be understood in a thorough and specific manner from these drawings. However, the drawings are provided for reference and illustration only and are not intended to limit the scope of this invention. Attached Figure Description

[0009] Figure 1: A block diagram of the first embodiment of the power conversion device of the present invention.

[0010] Figure 2: A block diagram of the three-phase power module of the power conversion device of the present invention.

[0011] Figure 3: A block diagram of a second embodiment of the power conversion device of the present invention.

[0012] Figure 4: A schematic diagram of one of the three-phase power modules of the power conversion device of the present invention being turned off.

[0013] Figure 5: A schematic diagram showing that one of the single-phase AC to DC conversion units of the complex three-phase power modules of the power conversion device of the present invention is turned off.

[0014] Figure 6: A circuit diagram of the low-frequency ripple current suppression circuit of the power conversion device of the present invention.

[0015] Figure 7: A block diagram of the power conversion system of the present invention.

[0016] Explanation of reference numerals in the attached figures: 10, 10-1~10-3: Power conversion device; 11~1N: Three-phase power module; 20: Switch matrix; 30: Controller; 41~4N: Low-frequency ripple current suppression circuit; 1111, 1121, 1131: Rectifier; 1112, 1122, 1132: Single-stage isolated power converter; 90: System controller; 411: First boost circuit; L1: First inductor; S1: First switch group. 11 First switch S 12 Second switch C1; First capacitor 412; Second boost circuit L2; Second inductor S2; Second switch group S 21 Third switch S 22 Fourth switch C2: Second capacitor

[0017] 413: Filter circuit C f1 First filter capacitor C f2 Second filter capacitor O: Equipotential node DC1: First DC side DC2: Second DC side V AC3 Three-phase AC power supply V R V S V T Three-phase AC voltage i dc1 i dc2 i dc3 ,…,i dcN DC current I rip Ripple Component I dc Output current P OUT ,P OUT1 ~P OUT3 Output power V RR V SR V TR : Rectified voltage i Rdc i Sdc i Tdc : Conversion current S SC Control signal S PM1 ,S PM2 ,S PM3 ,…,S PMN Module control signal SSYS1 ,S SYS2 ,S SYS3 System control signals Detailed Implementation

[0018] The technical content and detailed description of the present invention are explained below with reference to the accompanying drawings.

[0019] Figure 1 shows a block diagram of a first embodiment of the power conversion device of the present invention. In this embodiment, the power conversion device 10 includes a plurality of three-phase power modules 11, 12, 13, ..., 1N, a switch matrix 20, and a controller 30. Specifically, the plurality of three-phase power modules 11, 12, 13, ..., 1N includes a first three-phase power module 11, a second three-phase power module 12, a third three-phase power module 13, ... and an Nth three-phase power module 1N.

[0020] Each three-phase power module 11, 12, 13, ..., 1N includes three single-phase AC to DC conversion units 111, 112, 113 (see Figure 2, to be explained later), which respectively receive three-phase AC power V AC3 Three-phase AC voltage V R V S V T And convert the three-phase AC voltage V R V S V T Provide DC current i dc1 i dc2 i dc3 ,…,i dcN In embodiments of the present invention, each single-phase AC-to-DC conversion unit 111, 112, 113 is a resonant AC-to-DC conversion unit, such as an LLC AC-to-DC conversion unit, but this is not intended to limit the present invention. Specifically, the first three-phase power supply module 11 receives a three-phase AC power supply V. AC3 Three-phase AC voltage V R V S V T And convert the three-phase AC voltage V R V S V T Provide the first DC current i dc1 The second three-phase power module 12 receives three-phase AC power V. AC3 Three-phase AC voltage V R V S V T And convert the three-phase AC voltage V R V S V T Provide a second DC current i dc2 The third three-phase power module 13 receives three-phase AC power V.AC3 Three-phase AC voltage V R V S V T And convert the three-phase AC voltage V R V S V T Provide a third DC current i dc3 And so on, the Nth three-phase power module 1N receives three-phase AC power V. AC3 Three-phase AC voltage V R V S V T And convert the three-phase AC voltage V R V S V T Provide the Nth DC current i dcN .

[0021] Switch matrix 20 receives the DC current i provided by the three-phase power modules 11, 12, 13, ..., 1N. dc1 i dc2 i dc3 ,…,i dcN Specifically, the switch matrix 20 receives the first DC current i provided by the first three-phase power module 11. dc1 Receives the second DC current i provided by the second three-phase power module 12 dc2 Receives the third DC current i provided by the third three-phase power module 13 dc3 And so on, receiving the Nth DC current i provided by the Nth three-phase power module 1N. dcN In this invention, the switch matrix 20 is a device that can dynamically connect different power paths, commonly used in various electronic systems, especially in applications requiring flexible path selection. The basic structure of the switch matrix 20 typically includes multiple input and output channels, and the conduction paths of the input and output channels are determined by switching elements and corresponding control signals.

[0022] Controller 30 provides switch control signal S SC The control switch matrix 20 determines the DC current i. dc1 i dc2 i dc3 ,…,i dcN Provided output power P OUT Specifically, the controller 30 controls the signal S. SC Turning the input and output channels of the switch matrix 20 on or off determines the DC current i. dc1 i dc2 i dc3 ,…,i dcNThe output. For example, if the control signal S SC The switching matrix 20 is connected to the second DC current i dc2 up to the Nth DC current i dcN The input and output channels, and the off switch matrix 20 is connected to the first DC current i dc1 The input and output channels are thus turned off, thus shutting off the first DC current i. dc1 The output of and conduct the second DC current i dc2 up to the Nth DC current i dcN The output of makes the output power P OUT It can be the second DC current i dc2 up to the Nth DC current i dcN Determined by, and related to the first DC current i dc1 Irrelevant.

[0023] Please refer to Figure 2, which is a block diagram of the three-phase power module of the power conversion device of the present invention. As mentioned above, each three-phase power module 11, 12, 13, ..., 1N includes three single-phase AC-to-DC conversion units 111, 112, 113. Taking the first three-phase power module 11 shown in Figure 2 as an example, the first three-phase power module 11 includes a first single-phase AC-to-DC conversion unit 111, a second single-phase AC-to-DC conversion unit 112, and a third single-phase AC-to-DC conversion unit 113. Each single-phase AC-to-DC conversion unit 111, 112, 113 includes rectifiers 1111, 1121, 1131 and single-stage isolated power converters 1112, 1122, 1132. The rectifiers 1111, 1121, 1131 receive three-phase AC voltage V. R V S V T The voltage of one phase, and the rectified voltage is the rectified voltage V. RR V SR V TR Single-stage isolated power converters 1112, 1122, and 1132 receive rectified voltage V. RR V SR V TR And the converted rectified voltage V RR V SR V TR For the conversion current i Rdc i Sdc i Tdc The conversion current i of these single-phase AC to DC conversion units 111, 112, 113 Rdc i Sdc i Tdc Sum of the currents is the DC current i dc1 i dc2 i dc3 ,…,idcN .

[0024] Specifically, as shown in Figure 2, the first single-phase AC-to-DC conversion unit 111 includes a first rectifier 1111 and a first single-stage isolated power converter 1112. The second single-phase AC-to-DC conversion unit 112 includes a second rectifier 1121 and a second single-stage isolated power converter 1122. The third single-phase AC-to-DC conversion unit 113 includes a third rectifier 1131 and a third single-stage isolated power converter 1132. The first rectifier 1111 receives a three-phase AC power supply V. AC3 R-phase AC voltage V R And the rectified R-phase AC voltage V R The first rectified voltage V RR The first single-stage isolated power converter 1112 receives the first rectified voltage V. RR And convert the first rectified voltage V RR The first conversion current i Rdc The second rectifier 1121 receives three-phase AC power V. AC3 S-phase AC voltage V S And the rectified S-phase AC voltage V S The second rectified voltage V SR The second single-stage isolated power converter 1122 receives the second rectified voltage V. SR And convert the second rectified voltage V SR For the second conversion current i Sdc The third rectifier 1131 receives three-phase AC power V. AC3 The T-phase AC voltage V T And the rectified T-phase AC voltage V T The third rectified voltage V TR The third single-stage isolated power converter 1132 receives the third rectified voltage V. TR And convert the third rectified voltage V TR For the third conversion current i Tdc Furthermore, the first conversion current i Rdc Second conversion current i Sdc and the third conversion current i Tdc Sum of these as the first DC current i dc1 In summary, the same applies to the second three-phase power module 12, the third three-phase power module 13, and so on, to the Nth three-phase power module 1N, to obtain the second DC current i. dc2 Third DC current i dc3 And so on, the Nth DC current i dcN This will not be elaborated upon further here.

[0025] Please refer to Figure 3, which is a block diagram of a second embodiment of the power conversion device of the present invention. Compared to the first embodiment shown in Figure 1, the second embodiment shown in Figure 3 further includes a plurality of low-frequency ripple current suppression circuits 41, 42, ..., 4N. The number of these low-frequency ripple current suppression circuits 41, 42, ..., 4N is equal to the number of the three-phase power modules 11, 12, 13, ..., 1N, and each low-frequency ripple current suppression circuit 41, 42, ..., 4N is connected to the output side of each three-phase power module 11, 12, 13, ..., 1N. Specifically, these low-frequency ripple current suppression circuits 41, 42, ..., 4N include a first low-frequency ripple current suppression circuit 41, a second low-frequency ripple current suppression circuit 42, a third low-frequency ripple current suppression circuit 43, and so on, up to an Nth low-frequency ripple current suppression circuit 4N. The first low-frequency ripple current suppression circuit 41 is connected to the output side of the first three-phase power module 11, the second low-frequency ripple current suppression circuit 42 is connected to the output side of the second three-phase power module 12, the third low-frequency ripple current suppression circuit 43 is connected to the output side of the third three-phase power module 13, and so on, with the N low-frequency ripple current suppression circuit 4N connected to the output side of the Nth three-phase power module 1N.

[0026] Please refer to Figure 6, which is a circuit diagram of the low-frequency ripple current suppression circuit of the power conversion device of the present invention. As shown in Figure 6, taking the first low-frequency ripple current suppression circuit 41 as an example, the first low-frequency ripple current suppression circuit 41 includes a first boost circuit 411 and a second boost circuit 412. The second boost circuit 412 is connected to the first boost circuit 411. The first low-frequency ripple current suppression circuit 41 receives a voltage with ripple component I. rip The first DC current i dc1 Furthermore, the ripple component I is absorbed through the first boost circuit 411 and the second boost circuit 412. rip Therefore, by utilizing the circuit architecture design of the first low-frequency ripple current suppression circuit 41 described above, the suppression of the first DC current i can be achieved. dc1 Ripple component I rip Elimination.

[0027] The first boost circuit 411 includes a first inductor L1, a first switch group S1, and a first capacitor C1. The first inductor L1 has a first terminal and a second terminal, and the first terminal of the first inductor L1 is connected to the first DC side DC1. The first switch group S1 includes a first switch S 11 With the second switch S 12 First switch S 11 The first switch S has a first terminal and a second terminal. 11 The first terminal is connected to the second terminal of the first inductor L1, and the first switch S 11 The second end is connected to the equipotential node O. The second switch S... 12 The second switch S has a first terminal and a second terminal.12 The first terminal is connected to the second terminal of the first inductor L1. The first capacitor C1 has a first terminal and a second terminal; the first terminal of the first capacitor C1 is connected to the second switch S. 12 The second terminal of the first capacitor C1 is connected to the equipotential node O. Furthermore, the circuit structure of the second boost circuit 412 is similar to that of the first boost circuit 411, and therefore will not be described in detail here.

[0028] Referring again to Figure 6, the first low-frequency ripple current suppression circuit 41 further includes a filter circuit 413. The filter circuit 413 includes a first filter capacitor C. f1 With the second filter capacitor C f2 First filter capacitor C f1 It has a first terminal and a second terminal, and a first filter capacitor C f1 The first terminal is connected to the first DC side DC1, and the first filter capacitor C f1 The second terminal is connected to the equipotential node O. The second filter capacitor C... f2 It has a first terminal and a second terminal, and a second filter capacitor C. f2 The first terminal is connected to the second DC side DC2, and the second filter capacitor C f2 The second end is connected to the equipotential node O.

[0029] As mentioned above, in order to achieve the control of the first DC current i dc1 Ripple component I rip The elimination of [something] is achieved through the following control methods for the first switch group S1 of the first boost circuit 411 and the second switch group S2 of the second boost circuit 412. Incidentally, regarding the first switch group S1, the first switch S... 11 With the second switch S 12 and the third switch S of the second switch group S2 21 With the fourth switch S 22 The control can be achieved through the control signals generated by the controller or control unit. Therefore, the controller or control unit will not be drawn separately in the attached drawings, but will be described in advance.

[0030] The control signal generated by the controller (which may be controller 30 shown in Figure 1 or another controller) affects the first switch S of the first switch group S1. 11 With the second switch S 12 To achieve synchronous and complementary on / off switching. Furthermore, the control signal generated by the controller affects the third switch S of the second switch group S2. 21 With the fourth switch S 22 To enable synchronous and complementary on / off switching.

[0031] In one embodiment, the first switch S of the first switch group S1 11 The third switch S of the second switch group S2 21To ensure synchronous switching on and off. In another embodiment, the first switch S of the first switch group S1... 11 The third switch S of the second switch group S2 21 To enable asynchronous switching on and off.

[0032] The specific operation instructions for the first low-frequency ripple current suppression circuit 41 are as follows. The DC current i output from the output side of the first three-phase power supply module 11... dc1 The current flows into the first DC side DC1 and is filtered at high frequency by the filter circuit 413. Therefore, the filtered output DC current i dc1 The current flows into the first boost circuit 411 and the second boost circuit 412. As previously explained, the DC current i flowing into the first boost circuit 411 and the second boost circuit 412... dc1 By turning on the first switch S of the first switch group S1 11 and turn off the second switch S 12 , making the ripple component I rip via the first switch S 11 Energy is stored in the first inductor L1, and then the first switch S of the first switch group S1 is turned off. 11 and turn on the second switch S 12 This allows the energy stored in the first inductor L1 to pass through the second switch S. 12 Released to the first capacitor C1.

[0033] Similarly, by turning on the third switch S of the second switch group S2... 21 And turn off the fourth switch S 22 , making the ripple component I rip via the third switch S 21 Energy is stored in the second inductor L2, and then the third switch S of the second switch group S2 is turned off. 21 And turn on the fourth switch S 22 This allows the energy stored in the second inductor L2 to pass through the fourth switch S. 22 The current is released to the second capacitor C2. Thus, the DC current i can be converted through the first boost circuit 411 and the second boost circuit 412. dc1 Ripple component I rip The absorbed current, therefore the output current I flowing to the load. dc That is, it does not have ripple component I rip DC current.

[0034] Furthermore, reducing load demand can be achieved by shutting down the three-phase power module 11-1N. The load can be the electric vehicle's battery V. BATFor example (as shown in Figure 6). Please refer to Figure 4, which is a schematic diagram of one of the three-phase power modules of the power conversion device of the present invention being turned off. Specifically, as shown in Figure 4, according to the load power demand supplied by the power conversion device 10 (taking an electric vehicle as an example, the controller 30 can receive the charging information required by the electric vehicle), the controller 30 provides at least one module control signal S. PM1 ,S PM2 ,S PM3 ,…,S PMN At least one three-phase power module 11, 12, 13, ..., 1N is shut down. As shown in Figure 4, when the load power demand decreases, the module control signal S provided by the controller 30... PMN Power can be shut off from the Nth three-phase power module 1N, and only the three-phase power modules other than the Nth three-phase power module 1N can be used for operation. Alternatively, if the load power demand is further reduced, the power supply to other three-phase power modules can be shut off. Therefore, the number of three-phase power modules 11, 12, 13, ..., 1N can be controlled according to the load power demand.

[0035] Furthermore, in response to reduced load power demand, this can be achieved not only by shutting off the power supply to the three-phase power modules mentioned earlier, but also by shutting off at least one single-phase AC-to-DC conversion unit 111, 112, 113 of the three-phase power modules 11, 12, 13, ..., 1N. Specifically, based on the load power demand supplied by the power conversion device 10, the controller 30 provides at least one module control signal S. PM1 ,S PM2 ,S PM3 ,…,S PMN At least one single-phase AC-to-DC conversion unit 111, 112, 113 of the three-phase power modules 11, 12, 13, ..., 1N is turned off. Incidentally, the module control signal S... PM1 ,S PM2 ,S PM3 ,…,S PMN In addition to controlling the on / off state of individual three-phase power modules 11, 12, 13, ..., 1N, it can also further control the individual single-phase AC-to-DC conversion units 111, 112, 113 within them. For ease of explanation, only the module control signal S is used. PM1 ,S PM2 ,S PM3 ,…,S PMN The meaning is as shown.

[0036] For example, as shown in Figure 5, when the load power demand decreases, the module control signal S provided by the controller 30... PM1 The first single-phase AC to DC conversion unit 111 of the first three-phase power module 11 can be shut down, module control signal S PM2The second single-phase AC-to-DC conversion unit 122 of the second three-phase power module 12 can be shut down, as well as the module control signal S. PM3 The third single-phase AC-to-DC converter unit 133 of the third three-phase power module 13 can be shut down. In this embodiment, the controller 30 controls the shutdown of one single-phase AC-to-DC converter unit 111, 122, 133 in each of the three three-phase power modules 11-13. That is, the shut-down single-phase AC-to-DC converter units 111, 122, 133 receive three-phase AC voltage in staggered phases. Specifically, the shut-down single-phase AC-to-DC converter unit 111 receives the R-phase voltage of the three-phase AC voltage, the shut-down single-phase AC-to-DC converter unit 122 receives the S-phase voltage of the three-phase AC voltage, and the shut-down single-phase AC-to-DC converter unit 133 receives the three-phase AC voltage. The T-phase voltage of the AC voltage is maintained such that the number and configuration of the un-shutdown single-phase AC-to-DC converter units receiving the three-phase AC voltage are the same. That is, the un-shutdown single-phase AC-to-DC converter units 121 and 131 are connected to the R-phase voltage of the three-phase AC voltage, the un-shutdown single-phase AC-to-DC converter units 112 and 132 are connected to the S-phase voltage of the three-phase AC voltage, and the un-shutdown single-phase AC-to-DC converter units 113 and 123 are connected to the T-phase voltage of the three-phase AC voltage. This allows the power conversion device 10 to output a balanced three-phase current to suppress the generation of ripple current.

[0037] Alternatively, if the load power demand is further reduced, more single-phase AC to DC conversion units can be shut down. For example, the controller 30 can shut down the first single-phase AC-to-DC conversion unit 111 and the second single-phase AC-to-DC conversion unit 112 of the first three-phase power module 11, i.e., the T-phase voltage of the single-phase AC-to-DC conversion unit 113 that is not shut down is connected to the three-phase AC voltage; shut down the second single-phase AC-to-DC conversion unit 122 and the third single-phase AC-to-DC conversion unit 123 of the second three-phase power module 12, i.e., the R-phase voltage of the single-phase AC-to-DC conversion unit 121 that is not shut down is connected to the three-phase AC voltage; and shut down the third single-phase AC-to-DC conversion unit 133 and the first single-phase AC-to-DC conversion unit 131 of the third three-phase power module 13, i.e., the S-phase voltage of the single-phase AC-to-DC conversion unit 132 that is not shut down is connected to the three-phase AC voltage. In this way, the power supply of the power conversion device 10 can be reduced according to the load demand, and the power conversion device 10 can output a balanced three-phase current to suppress the generation of ripple current. Furthermore, under conditions of further reduced load power demand, i.e., extremely light load operation, if it is impossible to maintain the same number and configuration of single-phase AC-to-DC converters receiving three-phase AC voltage as before, for example, when all three single-phase AC-to-DC converters 111, 112, and 113 of the first three-phase power module 11 are turned off, while only single-phase AC-to-DC converters 122 and 123 are turned off in the second three-phase power module 12, and only single-phase AC-to-DC converters 133 and 131 are turned off in the third three-phase power module 13, under this situation, due to the asymmetrical three-phase power supply (in this example, the asymmetrical power supply caused by the reduction of the T-phase voltage output), the DC output terminal contains AC components with a harmonic frequency of more than twice the line frequency, and the DC (output) current i dc This will generate ripple components, affecting the quality of power supply to the load and even the lifespan of the load. Therefore, it is necessary to control and adjust the low-frequency ripple current suppression circuits 42 and 43 to achieve control over the DC current i. dc1 -i dc3 Ripple component I rip Elimination.

[0038] Furthermore, if the load power demand is so low that it only needs to be powered by a single-phase AC to DC conversion unit 132 in the third three-phase power module 13, the DC current ripple component caused by the unbalanced three-phase power supply can be eliminated by the control and adjustment of the low-frequency ripple current suppression circuit 43 corresponding to the third three-phase power module 13.

[0039] Therefore, even if the load power needs to be reduced further, the larger ripple component can be fully suppressed.

[0040] Furthermore, in response to reduced load power demand, this can be achieved not only by shutting down the three-phase power module (as described above) or by shutting down at least one single-phase AC-to-DC conversion unit of the three-phase power module, but also by simultaneously shutting down both the three-phase power module and the single-phase AC-to-DC conversion unit according to load demand. Specifically, the power conversion device 10 provides at least one module control signal S to the controller 30 according to the power demand of the supplied load. PM1 ,S PM2 ,S PM3 ,…,S PMN At least one three-phase power module 11, 12, 13, ..., 1N is shut down, and at least one single-phase AC-to-DC conversion unit 111, 112, 113 of the remaining three-phase power modules 11, 12, 13, ..., 1N is also shut down. For the operation combining the two shutdown methods, please refer to the foregoing description, which will not be repeated here. Any method that can reduce the power supply of the power conversion device 10 according to load demand and enable the power conversion device 10 to output a balanced three-phase current to suppress ripple current generation should be included within the scope of this invention.

[0041] Please refer to Figure 7, which is a block diagram of the power conversion system of the present invention. The power conversion system includes a plurality of power conversion devices 10-1, 10-2, 10-3 and a system controller 90. As shown in Figure 7, the invention is illustrated using three power conversion devices 10-1, 10-2, 10-3 as an example, but this is not intended to limit the invention. Specifically, the three power conversion devices 10-1, 10-2, 10-3 include a first power conversion device 10-1, a second power conversion device 10-2, and a third power conversion device 10-3. Incidentally, the circuit architecture and control method of each power conversion device 10-1, 10-2, 10-3 shown in Figure 7 are the same as those of the power conversion device 10 shown in Figure 1. In other words, if the power conversion device 10 in Figure 1 is a rack architecture, then Figure 7 indicates that the application environment includes three racks. That is, the multi-rack architecture shown in Figure 7 is cross-rack operation.

[0042] For the specific circuit architecture of each power conversion device 10-1, 10-2, and 10-3, please refer to the aforementioned content, which will not be repeated here. The system controller 90 is connected to the controllers 30 of the power conversion devices 10-1, 10-2, and 10-3, and controls these controllers 30 via communication to control the corresponding power conversion devices 10-1, 10-2, and 10-3 to output balanced power P. OUT1 ,P OUT2 ,P OUT3 Specifically, the system controller 90 is responsible for controlling and communicating all power conversion devices in the field, ensuring that the output power P output by these power conversion devices 10-1, 10-2, and 10-3 is...OUT1 ,P OUT2 ,P OUT3 This allows for a reduction in the power supply to the power conversion device in response to load demands, and enables the power conversion device 10 to output a balanced three-phase current to suppress ripple current generation. For example, under a light load power demand, the system controller 90 can provide multiple system control signals S. SYS1 ,S SYS2 ,S SYS3 That is, the first system control signal S SYS1 The first power conversion device 10-1 is controlled to retain power supply only to the first single-phase AC to DC conversion unit 111 of the first three-phase power module 11, and the second system control signal S SYS2 The control second power conversion device 10-2 retains only the power supply to the second single-phase AC to DC conversion unit 112 of the first three-phase power module 11, and the third system control signal S. SYS3 The third power conversion device 10-3 is controlled to retain power supply only to the third single-phase AC-to-DC conversion unit 113 of the first three-phase power module 11. This allows for a reduction in the power supply to the power conversion device 10 according to load demand, and ensures that the power conversion device 10 outputs a balanced three-phase current to suppress ripple current generation. Simultaneously, because the power supplied to each power conversion device 10-1, 10-2, and 10-3 by the three-phase power supply is balanced, there is no problem of uneven load shedding at the grid end, thus maintaining grid power balance. However, this is not intended to limit the invention. Any achievement of the invention's objectives and technical effects by shutting down or turning on the corresponding interleaved three-phase power modules or single-phase AC-to-DC conversion units should be included within the scope of this invention.

[0043] In summary, the present invention has the following features and advantages:

[0044] 1. Under light load conditions, in order to reduce the power supply to the power conversion device in response to the reduced power demand of the load, the three-phase power module can be shut down, so that the power conversion device outputs a balanced three-phase current to suppress the generation of ripple current.

[0045] 2. Under light load conditions, in order to reduce the power supply of the power conversion device in response to the reduced power demand of the load, the alternating shutdown of the single-phase AC to DC conversion unit can be controlled so that the power conversion device outputs a balanced three-phase current to suppress the generation of ripple current. At the same time, it also ensures that there is no problem of uneven load withdrawal of the three-phase power supply at the grid end, thereby maintaining the power supply balance at the grid end.

[0046] 3. By using a simple circuit design to control the low-frequency ripple current suppression circuit, the system efficiency can be maintained even under extremely light load conditions, and the ripple component of the DC current can be eliminated, so that the output current flowing to the load is a DC current without ripple components.

[0047] 4. By integrating and controlling multiple power conversion devices through the system controller, balanced output current can be achieved across rack application areas to maintain power supply balance at the grid end.

[0048] The above description is merely a detailed description and accompanying drawings of preferred embodiments of the present invention, and the features of the present invention are not limited thereto, nor are they intended to limit the present invention. The entire scope of the present invention should be determined by the following claims. All embodiments that conform to the concept of the claims of the present invention and similar variations thereof should be included in the scope of the present invention. Any variations or modifications that can be easily conceived by those skilled in the art within the field of the present invention can be covered by the following patent scope of the present disclosure.

Claims

1. A power conversion device, comprising: A plurality of three-phase power supply modules, each of which includes: Three single-phase AC to DC conversion units each receive the three-phase AC voltage from a three-phase AC power supply and convert the three-phase AC voltage to provide DC current. A switching matrix receives the DC current provided by the three-phase power module; and A controller provides a switching control signal to control the switching matrix to determine the output power provided by the DC current.

2. The power conversion device as claimed in claim 1, wherein each of the single-phase AC to DC conversion units comprises: A rectifier receives a voltage from one phase of the three-phase AC voltage and rectifies that voltage into a rectified voltage; and A single-stage isolated power converter receives the rectified voltage and converts the rectified voltage into a switching current; The sum of the conversion currents of the single-phase AC to DC conversion unit is the DC current.

3. The power conversion device of claim 1, wherein, in response to a decrease in the load power demand of a load supplied by the power conversion device, the controller provides at least one module control signal to shut down at least one three-phase power module.

4. The power conversion device of claim 1, wherein, in response to a decrease in the load power demand of a load supplied by the power conversion device, the controller provides at least one module control signal to shut down at least one single-phase AC-to-DC conversion unit of the three-phase power module.

5. The power conversion device as claimed in claim 4, wherein the at least one single-phase AC-to-DC conversion unit of the three-phase power module that is turned off receives the three-phase AC voltage in phase-shifted manner.

6. The power conversion device of claim 1, wherein, in response to a decrease in the load power demand of a load supplied by the power conversion device, the controller provides at least one module control signal to shut down the at least one three-phase power module and shuts down at least one single-phase AC-to-DC conversion unit of the remaining three-phase power modules.

7. The power conversion device of claim 6, wherein the at least one single-phase AC-to-DC conversion unit of the three-phase power module that is turned off receives the three-phase AC voltage in phase-out.

8. The power conversion device as claimed in claim 1, further comprising: A plurality of low-frequency ripple current suppression circuits are provided, the number of which is equal to the number of the three-phase power supply modules, and each low-frequency ripple current suppression circuit is connected to the output side of the respective three-phase power supply module.

9. The power conversion device of claim 8, wherein each of the low-frequency ripple current suppression circuits comprises: A first boost circuit includes: A first inductor, a first switching group, and a first capacitor; and A second boost circuit is connected to the first boost circuit, the second boost circuit comprising: A second inductor, a second switch group, and a second capacitor; Each of the low-frequency ripple current suppression circuits receives the DC current having a ripple component and absorbs the ripple component through the first boost circuit and the second boost circuit.

10. The power conversion device as claimed in claim 1, wherein each of the single-phase AC to DC conversion units is a resonant AC to DC conversion unit.

11. A power conversion system, comprising: A plurality of power conversion devices, each power conversion device comprising: A plurality of three-phase power supply modules, each of which includes: Three single-phase AC to DC conversion units each receive the three-phase AC voltage from a three-phase AC power supply and convert the three-phase AC voltage to provide DC current. A switching matrix receives the DC current provided by the three-phase power module; and A controller provides a switching control signal to control the switching matrix to determine the output power provided by the DC current; and A system controller is connected to the controller of the power conversion device and controls the controller via communication to control the output power of the corresponding power conversion device to achieve a balanced output power.

12. The power conversion system of claim 11, wherein each of the single-phase AC to DC conversion units comprises: A rectifier receives a voltage from one phase of the three-phase AC voltage and rectifies that voltage into a rectified voltage; and A single-stage isolated power converter receives the rectified voltage and converts the rectified voltage into a switching current; The sum of the conversion currents of the single-phase AC to DC conversion unit is the DC current.

13. The power conversion system of claim 11, wherein, in response to a decrease in the load power demand of a load supplied by the power conversion device, the controller provides at least one module control signal to shut down at least one three-phase power module.

14. The power conversion system of claim 11, wherein, in response to a decrease in the load power demand of a load supplied by the power conversion device, the controller provides at least one module control signal to shut down at least one single-phase AC-to-DC conversion unit of the three-phase power module.

15. The power conversion system of claim 14, wherein the at least one single-phase AC-to-DC conversion unit of the shut-down three-phase power module receives the three-phase AC voltage in phase-out.

16. The power conversion system of claim 11, wherein, in response to a decrease in the load power demand of a load supplied by the power conversion device, the controller provides at least one module control signal to shut down the at least one three-phase power module and shuts down at least one single-phase AC-to-DC conversion unit of the remaining three-phase power modules.

17. The power conversion system of claim 16, wherein the at least one single-phase AC-to-DC conversion unit of the three-phase power module that is turned off receives the three-phase AC voltage in phase-out.

18. The power conversion system of claim 11, wherein each of the power conversion devices further comprises: A plurality of low-frequency ripple current suppression circuits are provided, the number of which is equal to the number of the three-phase power supply modules, and each low-frequency ripple current suppression circuit is connected to the output side of the respective three-phase power supply module.

19. The power conversion system of claim 18, wherein each of the low-frequency ripple current suppression circuits comprises: A first boost circuit includes: A first inductor, a first switching group, and a first capacitor; and A second boost circuit is connected to the first boost circuit, the second boost circuit comprising: A second inductor, a second switch group, and a second capacitor; Each of the low-frequency ripple current suppression circuits receives the DC current having a ripple component and absorbs the ripple component through the first boost circuit and the second boost circuit.

20. The power conversion system of claim 11, wherein each of the single-phase AC-to-DC conversion units is a resonant AC-to-DC conversion unit.

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