Power converter and power conversion system

Abstract

Provide a power conversion device. 【Solution means】It includes a plurality of three-phase power modules 11, 12, 13, 1N, a switch matrix 20, and a controller 30. Each three-phase power module 11, 12, 13, 1N receives a three-phase AC voltage V AC3 of a three-phase AC power supply V R 、V S 、V T and converts the three-phase AC voltage V R 、V S 、V T into direct current i dc1 、i dc2 、i dc3 、i dcN and includes three single-phase AC / DC conversion units for supplying. The switch matrix 20 receives the direct current i dc1 、i dc2 、i dc3 、i dcN supplied from these three-phase power modules 11, 12, 13, 1N. The controller 30 supplies a switch control signal S SC for controlling the switch matrix 20 in order to determine the output power P OUT supplied by the direct current i dc1 、i dc2 、i dc3 、i dcN .

Description

[Technical Field]

[0001] The present invention relates to a power conversion device and a power conversion system, and more particularly to a power conversion device and a power conversion system equipped with a low-frequency ripple current suppression function. [Background technology]

[0002] With growing interest in environmental protection and green energy, electric vehicle sales are tending to double, and the demand for charging stations is increasing. Meeting the charging needs of electric vehicles, especially those with very light loads, while balancing overall power efficiency and charging quality is a goal that those skilled in the art should jointly address. [Overview of the Initiative] [Problems that the invention aims to solve]

[0003] Therefore, designing power conversion devices and power conversion systems that overcome the problems and technical bottlenecks of conventional technologies is an important challenge for the inventors of this application. [Means for solving the problem]

[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 receives a three-phase AC voltage from a three-phase AC power supply and includes three single-phase AC / DC conversion units that convert the three-phase AC voltage to supply a DC current. The switch matrix receives the DC current supplied from the three-phase power modules. The controller supplies switch control signals to control the switch matrix in order to determine the output power supplied by the DC current.

[0005] As a result, the power converter according to the present invention has the following features and advantages: 1. In the case of light load, in order to reduce the power supply of the power converter in accordance with the decrease in load power demand, it is possible to suppress the generation of ripple current by controlling the power converter to receive a balanced three-phase current from the AC power source by turning off the three-phase power module. 2. In the case of light load, in order to reduce the power supply of the power converter in accordance with the decrease in load power demand, it is possible to suppress the generation of ripple current by shifting and turning off the single-phase AC / DC conversion unit, thereby allowing the power converter to receive a balanced three-phase current from the AC power source. 3. By realizing the control of the low-frequency ripple current suppression circuit with a simple circuit design, it is possible to remove the ripple component of the DC current while maintaining system efficiency in the case of extremely light load, and to make the output current flowing to the load a DC current that does not contain the 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 / DC conversion units that receive the three-phase AC voltage of a three-phase AC power supply and convert the three-phase AC voltage to supply DC current. The switch matrix receives the DC current supplied from the three-phase power modules. The controller supplies switch control signals to control the switch matrix in order to determine the output power supplied by the DC current. The system controller is connected to the controller of the power conversion device and controls the controller via communication so that the corresponding power conversion device outputs the balanced output power.

[0007] As a result, the power conversion system according to the present invention has the following features and advantages: 1. In the case of light load, in order to reduce the power supply of the power conversion device in accordance with the decrease in load power demand, it is possible to suppress the generation of ripple current by controlling the power conversion device to receive a balanced three-phase current from the AC power source by turning off the three-phase power module. 2. In the case of light load, in order to reduce the power supply of the power conversion device in accordance with the decrease in load power demand, it is possible to suppress the generation of ripple current by shifting and turning off the single-phase AC / DC conversion unit, thereby allowing the power conversion device to receive a balanced three-phase current from the AC power source, and also eliminating load imbalance in the three-phase power source on the power grid side, thereby maintaining the power supply balance on the power grid side. 3. By realizing the control of the low-frequency ripple current suppression circuit with a simple circuit design, it is possible to remove the ripple component of the DC current while maintaining system efficiency in the case of extremely light load, and to make the output current flowing to the load a DC current that does not contain the ripple component. 4. By integrally controlling multiple power conversion devices using a system controller, it is possible to realize a balanced input current in the usage field across cross cabinets, and maintain the power supply balance on the power grid side.

[0008] To further understand the techniques, means, and effects for achieving the predetermined objectives of the present invention, please refer to the following detailed description of the invention and the accompanying drawings. The following detailed description and accompanying drawings will provide a more concrete and in-depth understanding of the objectives, features, and characteristics of the present invention, but the accompanying drawings are not intended to limit the invention and are provided for reference and illustrative purposes only. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram of a first embodiment of the power conversion device according to the present invention. [Figure 2] This is a block diagram of a three-phase power module in a power conversion device according to the present invention. [Figure 3] This is a block diagram of a second embodiment of the power conversion device according to the present invention. [Figure 4] It is a schematic diagram showing that one of the three - phase power modules in the power conversion device according to the present invention is turned off. [Figure 5] It is a schematic diagram showing that one of the single - phase AC / DC conversion units of a plurality of three - phase power modules in the power conversion device according to the present invention is turned off. [Figure 6] It is a circuit diagram of a low - frequency ripple current suppression circuit in the power conversion device according to the present invention. [Figure 7] It is a block diagram of a power conversion system according to the present invention.

Embodiments for Carrying out the Invention

[0010] Hereinafter, the specific technical content of the present invention will be described while referring to the drawings.

[0011] FIG. 1 is a block diagram of a first embodiment of a power conversion device according to 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 include 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.

[0012] Each of the three - phase power modules 11, 12, 13, …, 1N receives three - phase AC voltages V AC3 of a three - phase AC power supply V R , V S , V T and converts the three - phase AC voltages V R , V S , V T into direct - current currents i dc1 , i dc2 , i dc3 , …, i dcNThe invention includes three single-phase AC / DC conversion units 111, 112, and 113 (see Figure 2; details will be described later) that supply a three-phase AC power supply V AC3 3-phase AC voltage V R , V S , V T In response, the three-phase AC voltage V R , V S , V T Convert to the first DC current i dc1 The second three-phase power module 12 supplies the three-phase AC power V AC3 3-phase AC voltage V R , V S , V T In response, the three-phase AC voltage V R , V S , V T Convert to the second DC current i dc2 The third three-phase power module 13 supplies the three-phase AC power V AC3 3-phase AC voltage V R , V S , V T In response, the three-phase AC voltage V R , V S , V T Convert to the third DC current i dc3 It supplies the following. Similarly, the Nth three-phase power module 1N supplies the three-phase AC power V AC3 3-phase AC voltage V R , V S , V T In response, the three-phase AC voltage V R , V S , V T Convert to obtain the Nth DC current i dcN To supply.

[0013] The switch matrix 20 receives DC current i from the 3-phase power modules 11, 12, 13, ..., 1N. dc1 i dc2 i dc3 , ..., i dcNSpecifically, the switch matrix 20 receives the first DC current i supplied from the first three-phase power module 11. dc1 In response, the second DC current i supplied from the second three-phase power module 12 dc2 In response, the third DC current i supplied from the third three-phase power module 13 dc3 Following this, the Nth DC current i supplied from the Nth three-phase power module 1N is then calculated in the same manner. dcN In this invention, the switch matrix 20 is a device that can dynamically connect different power paths and is widely used in various electronic systems, especially in applications where flexible path selection is required. The basic structure of the switch matrix 20 generally includes multiple input channels and output channels, and the conduction paths of the input channels and output channels are determined by switch elements and corresponding control signals.

[0014] Controller 30 controls the DC current i dc1 i dc2 i dc3 , ..., i dcN Output power P supplied by OUT Switch control signals S for controlling the switch matrix 20 to determine this. SC It supplies the control signal S. Specifically, the controller 30 supplies the control signal S. SC By turning the input and output channels of the switch matrix 20 on or off, the DC current i dc1 i dc2 i dc3 , ..., i dcN Determine the output of the control signal S. SC Therefore, the second DC current i dc2 From the Nth DC current i dcN The input and output channels of the corresponding switch matrix 20 are turned on, and the first DC current i dc1 When the input and output channels of the corresponding switch matrix 20 are turned off, the first DC current i dc1 The output of is turned off, and the second DC current i dc2from the first to the Nth DC current i dcN The output is turned on, so the output power P OUT is determined by the second DC current i dc2 from the second to the Nth DC current i dcN and is independent of the first DC current i dc1 .

[0015] Figure 2 is a block diagram of the three-phase power module of the power conversion device according to the present invention. As described above, each of the three-phase power modules 11, 12, 13,..., 1N includes three single-phase AC / DC conversion units 111, 112, 113. Taking the first three-phase power module 11 shown in FIG. 2 as an example, the first three-phase power module 11 includes a first single-phase AC / DC conversion unit 111, a second single-phase AC / DC conversion unit 112, and a third single-phase AC / DC conversion unit 113. Each single-phase AC / DC conversion unit 111, 112, 113 includes a rectifier 1111, 1121, 1131 and a single-stage isolation type power converter 1112, 1122, 1132. The rectifiers 1111, 1121, 1131 receive one phase voltage of the three-phase AC voltages V R , V S , V T and rectify the voltage to the rectified voltages V RR , V SR , V TR . The single-stage isolation type power converters 1112, 1122, 1132 receive the rectified voltages V RR , V SR , V TR and convert the rectified voltages V RR , V SR , V TR into the conversion currents i Rdc , i Sdc , i Tdc . In each three-phase power module, the conversion currents i Rdc , i Sdc , i Tdc output from the single-phase AC / DC conversion units 111, 112, 113 are summed up to become the DC current (for example, i dc1 in the first module) of the three-phase power module.

[0016] Specifically, as shown in FIG. 2, the first single-phase AC / DC conversion unit 111 includes a first rectifier 1111 and a first single-stage isolated power converter 1112. The second single-phase AC / DC conversion unit 112 includes a second rectifier 1121 and a second single-stage isolated power converter 1122. The third single-phase AC / DC conversion unit 113 includes a third rectifier 1131 and a third single-stage isolated power converter 1132. The first rectifier 1111 receives the R-phase AC voltage V AC3 of the three-phase AC power supply V R and rectifies the R-phase AC voltage V R into the first rectified voltage V RR . The first single-stage isolated power converter 1112 receives the first rectified voltage V RR and converts the first rectified voltage V RR into the first converted current i Rdc . The second rectifier 1121 receives the S-phase AC voltage V AC3 of the three-phase AC power supply V S and rectifies the S-phase AC voltage V S into the second rectified voltage V SR . The second single-stage isolated power converter 1122 receives the second rectified voltage V SR and converts the second rectified voltage V SR into the second converted current i Sdc . The third rectifier 1131 receives the T-phase AC voltage V AC3 of the three-phase AC power supply V T and rectifies the T-phase AC voltage V T into the third rectified voltage V TR . The third single-stage isolated power converter 1132 receives the third rectified voltage V TR and converts the third rectified voltage V TR into the third converted current i Tdc . Furthermore, the sum of the first converted current i Rdc , the second converted current i Sdc and the third converted current i Tdc is the first DC current i dc1 . The above description is similarly applicable to the second three-phase power module 12, the third three-phase power module 13,..., the Nth three-phase power module 1N, and the second DC current i dc2 , the third DC current i dc3 ,..., the Nth DC current idcN This is obtained, and a repeated explanation here will be omitted.

[0017] Figure 3 is a block diagram of a second embodiment of the power conversion device according to the present invention. The second embodiment shown in Figure 3 further includes a plurality of low-frequency ripple current suppression circuits 41, 42, ..., 4N compared to the first embodiment shown in Figure 1. Here, the number of low-frequency ripple current suppression circuits 41, 42, ..., 4N is the same as the number of 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, the 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 an Nth low-frequency ripple current suppression circuit 4N. A first low-frequency ripple current suppression circuit 41 is connected to the output side of the first three-phase power module 11, a second low-frequency ripple current suppression circuit 42 is connected to the output side of the second three-phase power module 12, a 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 nth low-frequency ripple current suppression circuit 4N being connected to the output side of the nth three-phase power module 1N.

[0018] Figure 6 is a circuit diagram of a low-frequency ripple current suppression circuit of a power converter according to 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 suppresses the ripple component I rip A first DC current i having dc1 In response, the ripple component I is passed through the first boost circuit 411 and the second boost circuit 412. rip This eliminates the first low-frequency ripple current suppression circuit 41 described above. dc1 Ripple component I rip It can be removed.

[0019] 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 end connected to the first DC side DC1 and a second end. The first switch group S1 includes a first switch S 11 and the second switch S 12 Includes the first switch S 11 It includes a first end connected to the second end of the first inductor L1 and a second end connected to the equipotential node O. Second switch S 12 This includes a first terminal connected to the second terminal of the first inductor L1, and a second terminal. The first capacitor C1 is connected to the second switch S 12 It includes a first end connected to the second end of and a second end connected to the equipotential node O. Since the circuit configuration of the second boost circuit 412 is the same as that of the first boost circuit 411, a detailed explanation is omitted here.

[0020] 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 And the second filter capacitor C f2 This includes the first filter capacitor C. f1 It includes a first end connected to the first DC side DC1 and a second end connected to the equipotential node O. The second filter capacitor C f2 It includes a first end connected to a second DC side DC2 and a second end connected to an equipotential node O.

[0021] As mentioned above, the first DC current i dc1 Ripple component I rip In order to achieve the removal of the first switch group S1 of the first boost circuit 411 and the second switch group S2 of the second boost circuit 412 are controlled as follows. Incidentally, the first switch S of the first switch group S1 11 and the second switch S 12 , and the third switch S of the second switch group S2 21 and the fourth switch S22 Control can be achieved by control signals generated by a controller or control unit, and the controller or control unit is not shown separately in the drawings.

[0022] The control signal generated by the controller (controller 30 shown in Figure 1 or another controller) is transmitted to the first switch S of the first switch group S1. 11 and the second switch S 12 The switches are turned on / off synchronously and complementaryly. Furthermore, the control signals generated by the controller are used to control the third switch S of the second switch group S2. 21 and the fourth switch S 22 Turn them on / off synchronously and complementaryly.

[0023] In one embodiment, the first switch S of the first switch group S1 11 and the third switch S of the second switch group S2 21 These are switched on / off synchronously. In another embodiment, the first switch S of the first switch group S1 11 and the third switch S of the second switch group S2 21 It is turned on / off asynchronously.

[0024] The specific operation of the first low-frequency ripple current suppression circuit 41 is as follows: The DC current i output from the output side of the first three-phase power module 11 dc1 It flows into the first DC side DC1, where high-frequency noise is removed by the filter circuit 413. Then the filtered DC current i dc1 The current flows into the first boost circuit 411 and the second boost circuit 412. As described above, the DC current i flows into the first boost circuit 411 and the second boost circuit 412. dc1 Ripple component I rip This is the first switch S of the first switch group S1. 11 Turn on the second switch S 12 By turning it off, energy is stored in the first inductor L1. Then, the first switch S of the first switch group S1 11 Turn off the second switch S12 By turning on the first inductor L1, the energy stored in the second switch S 12 It is discharged to the first capacitor C1 via [the specified method].

[0025] Similarly, the third switch S of the second switch group S2 21 Turn on the fourth switch S 22 By turning off Ripple component I rip The third switch S 21 The energy is then guided to the second inductor L2, where it is stored, and then to the third switch S of the second switch group S2. 21 Turn off the fourth switch S 22 By turning it on, the energy stored in the second inductor L2 is released by the fourth switch S 22 It is discharged to the second capacitor C2 via this. In this way, the DC current i dc1 Ripple component I rip The first boost circuit 411 and the second boost circuit 412 can remove the output current I flowing to the load. dc Ripple component I rip This results in a DC current that does not include [something].

[0026] Furthermore, operation in the event of a decrease in load demand can be achieved by turning off the 3-phase power module 11-1N. Here, the load is the battery V of an electric vehicle. BAT Examples include (see Figure 6). Figure 4 is a schematic diagram showing that one of the three-phase power modules in the power conversion device according to the present invention has been turned off. Specifically, as shown in Figure 4, the controller 30 issues at least one module control signal S in response to the power demand of the load to which the power conversion device 10 supplies power (taking an electric vehicle as an example load, the controller 30 can receive charging information required by the electric vehicle). PM1 S PM2 S PM3 , ..., S PMNThe controller 30 supplies a module control signal S when the load power demand decreases, for example, as shown in Figure 4. PMN This switches off the power supply to the Nth three-phase power module 1N, leaving only the other three-phase power modules operational. Furthermore, if the load power demand decreases further, it is possible to switch off the power supply to other three-phase power modules as well. Thus, the number of three-phase power modules 11, 12, 13, ..., 1N supplied with power can be controlled according to the load power demand.

[0027] Furthermore, responding to a decrease in load power demand can be achieved not only by turning off the power supply to the three-phase power module as described above, but also by turning off at least one single-phase AC / DC conversion unit 111, 112, 113 of the three-phase power modules 11, 12, 13, ..., 1N. Specifically, the controller 30 issues at least one module control signal S in response to the load power demand supplied by the power converter 10. PM1 S PM2 S PM3 , ..., S PMN The module control signal S is supplied to turn off at least one single-phase AC / DC conversion unit 111, 112, 113 of the three-phase power modules 11, 12, 13, ..., 1N. PM1 S PM2 S PM3 , ..., S PMN It is not only capable of controlling the on / off state of a single three-phase power module 11, 12, 13, ..., 1N, but can also further control the single single-phase AC / DC conversion units 111, 112, 113 located within it, but for the sake of explanation, the module control signal S PM1 S PM2 S PM3 , ..., S PMN Only the basics are shown schematically.

[0028] For example, as shown in Figure 5, when the load power demand decreases, the module control signal S supplied from the controller 30...PM1 This turns off the first single-phase AC / DC conversion unit 111 of the first three-phase power module 11, and the module control signal S PM2 This turns off the second single-phase AC / DC conversion unit 122 of the second three-phase power module 12, and the module control signal S PM3 It is possible to turn off the third single-phase AC / DC converter unit 133 of the third three-phase power module 13. In this embodiment, the controller 30 controls the turning off of one single-phase AC / DC converter unit 111, 122, and 133 in each of the three three-phase power modules 11-13, i.e., the turned-off single-phase AC / DC converter units 111, 122, and 133 each correspond to different AC voltage phases. Specifically, the turned-off single-phase AC / DC converter unit 111 corresponds to the R-phase voltage of the three-phase AC voltage, the turned-off single-phase AC / DC converter unit 122 corresponds to the S-phase voltage of the three-phase AC voltage, and the turned-off single-phase AC / DC converter unit 133 corresponds to the T-phase voltage of the three-phase AC voltage. This ensures that the number and arrangement of single-phase AC / DC conversion units connected to each AC voltage phase and not switched off remain the same; that is, the single-phase AC / DC conversion units 121 and 131 that are not switched off are connected to the R-phase voltage of the three-phase AC voltage, the single-phase AC / DC conversion units 112 and 132 that are not switched off are connected to the S-phase voltage of the three-phase AC voltage, and the single-phase AC / DC conversion units 113 and 123 that are not switched off are connected to the T-phase voltage of the three-phase AC voltage. As a result, the power converter 10 can suppress the generation of ripple current by inputting a balanced three-phase current from the AC power supply.

[0029] Furthermore, if the load power demand decreases further, it is possible to turn off other single-phase AC / DC conversion units. For example, the controller 30 turns off the first single-phase AC / DC conversion unit 111 and the second single-phase AC / DC conversion unit 112 of the first three-phase power module 11 (the single-phase AC / DC conversion unit 113, which is not turned off, is connected to the T-phase voltage of the three-phase AC voltage), and turns off the second single-phase AC / DC conversion unit 122 and the third single-phase AC / DC conversion unit 123 of the second three-phase power module 12 (the single-phase AC / DC conversion unit 121, which is not turned off, is connected to the R-phase voltage of the three-phase AC voltage). It is possible to turn off the third single-phase AC / DC conversion unit 133 and the first single-phase AC / DC conversion unit 131 of the third three-phase power module 13 (the single-phase AC / DC conversion unit 132 that is not turned off is connected to the S-phase voltage of the three-phase AC voltage), and in this case as well, it is possible to reduce the power supply to the power converter 10 in response to the decrease in load demand and suppress the generation of ripple current so that the power converter 10 receives a balanced three-phase current from the AC power supply.

[0030] Furthermore, if the load power demand decreases further, i.e., operation at extremely light loads is required, it may not be possible to maintain the same AC voltage across all AC voltage phases for the operating single-phase AC / DC conversion units. For example, in the first three-phase power module 11, all three single-phase AC / DC conversion units 111, 112, and 113 are turned off; in the second three-phase power module 12, only single-phase AC / DC conversion units 122 and 123 are turned off; and in the third three-phase power module 13, only single-phase AC / DC conversion units 133 and 131 are turned off. In this case, asymmetrical three-phase power draw-in occurs (in this example, asymmetrical power draw-in due to the absence of current draw-in from the T phase), resulting in the inclusion of harmonic components at the DC output terminal that are more than twice the line frequency, causing the DC (output) current i dc Ripple components are generated, which can negatively affect the quality of power supply to the load and, consequently, the lifespan of the load. Therefore, by controlling and adjusting the low-frequency ripple current suppression circuits 42 and 43, the DC current i dc1 -i dc3Ripple component I rip It is necessary to eliminate it.

[0031] Furthermore, if the load power demand decreases to the point where power supply from only the single-phase AC / DC conversion unit 132 of the third three-phase power module 13 is sufficient, the ripple component of the DC current due to the unbalanced three-phase power draw can be eliminated by controlling and adjusting the low-frequency ripple current suppression circuit 43 corresponding to the third three-phase power module 13.

[0032] Therefore, even if the load power demand decreases further, it will be possible to sufficiently suppress larger ripple components.

[0033] Furthermore, responding to a decrease in load power demand can be achieved by turning off the power supply to the three-phase power module or by turning off at least one single-phase AC / DC conversion unit of the three-phase power module, as described above. Alternatively, it can be achieved by simultaneously turning off the three-phase power module and the single-phase AC / DC conversion unit depending on the load demand. Specifically, the controller 30 sends at least one module control signal S to turn off at least one three-phase power module 11, 12, 13, ..., 1N and at least one single-phase AC / DC conversion unit 111, 112, 113 of the remaining three-phase power modules 11, 12, 13, ..., 1N, depending on the load power demand of the load power supplied by the power converter 10. PM1 S PM2 S PM3 , ..., S PMN The power supply is supplied. For the operation of combining the two off methods, please refer to the above description, and a detailed explanation will not be repeated here. As long as it is possible to reduce the power supply of the power converter 10 in response to a decrease in load demand and to suppress the generation of ripple current so that the power converter 10 receives a balanced three-phase current from the AC power supply, all of these are included within the scope of the present invention.

[0034] Figure 7 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. Although Figure 7 illustrates three power conversion devices 10-1, 10-2, and 10-3 as examples, the present invention is not limited thereto. Specifically, the three power conversion devices 10-1, 10-2, and 10-3 include the first power conversion device 10-1, the second power conversion device 10-2, and the third power conversion device 10-3. The circuit configuration and control method of each power conversion device 10-1, 10-2, and 10-3 shown in Figure 7 are the same as those of the power conversion device 10 shown in Figure 1. That is, if the power conversion device 10 in Figure 1 is assumed to be a single cabinet configuration, Figure 7 shows that it includes three cabinets in the field of use. In other words, the multiple cabinet configurations shown in Figure 7 represent cross-cabinet control.

[0035] For the specific circuit configurations of each power converter 10-1, 10-2, and 10-3, please refer to the explanation above. A detailed explanation is omitted here. The system controller 90 is connected to the controllers 30 of the power converters 10-1, 10-2, and 10-3, and communicates with the controllers 30 to control the balanced output power P of the corresponding power converters 10-1, 10-2, and 10-3. OUT1 , P OUT2 , P OUT3 Specifically, the system controller 90 is responsible for controlling and communicating with all power converters in the field, and controls the output power P output from power converters 10-1, 10-2, and 10-3. OUT1 , P OUT2 , P OUT3 Regarding this, the power supply to the power converter is reduced in response to a decrease in load demand, and the power converter 10 is made capable of suppressing the generation of ripple current by inputting a balanced three-phase current from the AC power source. For example, in the case of a light load power supply demand, the system controller 90 outputs multiple system control signals S SYS1 S SYS2 S SYS3 It supplies the first system control signal S SYS1The first power converter 10-1 controls the first power converter 10-1 to maintain only the power supply from the first single-phase AC / DC converter 111 of the first three-phase power module 11, and the second system control signal S SYS2 The second power converter 10-2 controls the first three-phase power module 11 to maintain only the power supply by the second single-phase AC / DC conversion unit 112, and the third system control signal S SYS3 This controls the third power converter 10-3 to maintain only the power supply from the third single-phase AC / DC conversion unit 113 of the first three-phase power module 11. This reduces the power supply from the power converter 10 in response to a decrease in load demand, and suppresses the generation of ripple current so that the power converter 10 receives a balanced three-phase current from the AC power supply. As a result, since the power supplied from the three-phase power supply to each power converter 10-1, 10-2, and 10-3 is balanced, it prevents problems such as load imbalance in the three-phase power supply on the power grid side, and maintains the power supply balance of the power grid. However, the present invention is not limited thereto, and everything that can achieve the objectives and effects of the present invention by switching the three-phase power module or single-phase AC / DC conversion unit on / off in a staggered manner by the corresponding phases is included within the scope of the present invention.

[0036] As described above, the present invention has the following features and advantages.

[0037] 1. In the case of light load, in order to reduce the power supply from the power converter in accordance with the decrease in load power demand, it is possible to suppress the generation of ripple current by turning off the 3-phase power module and controlling the power converter to receive a balanced 3-phase current from the AC power source.

[0038] 2. In the case of light load, in order to reduce the power supply of the power converter in accordance with the decrease in load power demand, it is possible to reduce the power supply to the power converter by shifting and turning off the single-phase AC / DC conversion unit, thereby inputting a balanced three-phase current from the AC power source to the power converter and suppressing the generation of ripple current. Furthermore, it is possible to eliminate load imbalance in the three-phase power source on the power grid side and maintain the power supply balance on the power grid side.

[0039] 3. By implementing control of the low-frequency ripple current suppression circuit with a simple circuit design, it is possible to remove the ripple component of the DC current while maintaining system efficiency under extremely light loads, thereby providing the output current flowing to the load as a DC current free of ripple components.

[0040] 4. By using a system controller to integrally control multiple power converters, it is possible to achieve balanced input currents in the usage field across cross cabinets and maintain the power supply balance on the power grid side.

[0041] The above is merely a detailed description and drawings of preferred specific embodiments of the present invention and is not intended to limit the present invention, nor are its features limited thereto. The scope of the present invention is entirely subject to the following claims, and any similar embodiments without departing from the spirit of the claims are included within the scope of the present invention, and any changes or modifications that are easily conceivable by a person skilled in the art may be included within the claims of the present invention. [Explanation of Symbols]

[0042] 10, 10-1~10-3 Power Conversion Device 11~1N 3-phase power supply module 20-switch matrix 30 controllers 41-4N Low-Frequency Ripple Current Suppression Circuit 1111, 1121, 1131 rectifier 1112, 1122, 1132 Single-stage isolated power converter 90 System Controllers 411 First Boost Circuit L1 First Inductor S1 1st group of switches S 11 First switch S 12 Second switch C1 First capacitor 412 Second Boost Circuit L2 Second Inductor S2 Second Switch Group S 21 The third switch S 22 The fourth switch C2 Second capacitor 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 3 phase AC power supply V R , V S , V T 3-phase AC voltage i dc1 i dc2 i dc3 , ..., i dcN direct current I rip Ripple components 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 signals S PM1 S PM2 SPM3 , ..., S PMN Module control signals S SYS1 S SYS2 S SYS3 System control signals

Claims

1. Multiple three-phase power modules, each having three single-phase AC / DC conversion units that receive a three-phase AC voltage from a three-phase AC power supply and convert the three-phase AC voltage to supply a DC current, A switch matrix that receives the DC current supplied from the three-phase power module, A controller that supplies switch control signals for controlling the switch matrix in order to determine the output power supplied by the DC current, A power conversion device, including a power converter.

2. Each of the single-phase AC / DC conversion units is, A rectifier that receives the voltage of one phase of the three-phase AC voltage and rectifies the voltage into a rectified voltage, A single-stage isolated power converter that receives the rectified voltage, converts the rectified voltage, and outputs it as a converted current, Includes, The power conversion device according to claim 1, wherein the sum of the conversion currents of the single-phase AC / DC conversion unit becomes the DC current.

3. The power converter according to claim 1, wherein the controller supplies at least one module control signal to turn off at least one three-phase power module in response to a decrease in the load power demand of a load powered by the power converter.

4. The power converter according to claim 1, wherein the controller supplies at least one module control signal to turn off at least one single-phase AC / DC conversion unit of the three-phase power module in response to a decrease in the load power demand of the load power supplied by the power converter.

5. The power conversion device according to claim 4, wherein the at least one single-phase AC / DC conversion unit of the three-phase power module that is turned off is configured to receive AC voltage of a different phase of the three-phase AC voltage.

6. The power converter according to claim 1, wherein the controller supplies at least one module control signal to turn off at least one three-phase power module and at least one single-phase AC / DC conversion unit of the remaining three-phase power modules in response to a decrease in the load power demand of the load power supplied by the power converter.

7. The power converter according to claim 6, wherein the at least one single-phase AC / DC converter unit of the three-phase power module that is turned off is configured to receive AC voltages of different phases of the three-phase AC voltages.

8. The power conversion device according to claim 1, further comprising a plurality of low-frequency ripple current suppression circuits, the same number as the number of three-phase power modules, and each of the three-phase power modules being connected to the output side.

9. Each of the low-frequency ripple current suppression circuits is: A first boost circuit having a first inductor, a first group of switches, and a first capacitor, A second boost circuit is connected to the first boost circuit and includes a second inductor, a second group of switches, and a second capacitor. Includes, The power conversion device according to claim 8, wherein each of the low-frequency ripple current suppression circuits receives the DC current having a ripple component and removes the ripple component via the first boost circuit and the second boost circuit.

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

11. Multiple power conversion devices, each of which, Multiple three-phase power modules, each having three single-phase AC / DC conversion units that receive a three-phase AC voltage from a three-phase AC power supply and convert the three-phase AC voltage to supply a DC current, A switch matrix that receives the DC current supplied from the three-phase power module, A controller that supplies switch control signals for controlling the switch matrix in order to determine the output power supplied by the DC current, Multiple power converters, A system controller connected to the controller of the power converter, which controls the controller via communication so that the corresponding power converter outputs the balanced output power, A power conversion system, including a power conversion system.

12. Each of the single-phase AC / DC conversion units is, A rectifier that receives the voltage of one phase of the three-phase AC voltage and rectifies the voltage into a rectified voltage, A single-stage isolated power converter that receives the rectified voltage, converts the rectified voltage, and outputs it as a converted current, Includes, The power conversion system according to claim 11, wherein the sum of the conversion currents of the single-phase AC / DC conversion unit becomes the DC current.

13. The power conversion system according to claim 11, wherein the controller supplies at least one module control signal to turn off at least one three-phase power module in response to a decrease in the load power demand of a load powered by the power conversion device.

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

15. The power conversion system according to claim 14, wherein the at least one single-phase AC / DC conversion unit of the three-phase power module that is turned off is configured to receive the AC voltage of a different phase of the three-phase AC voltage.

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

17. The power conversion system according to claim 16, wherein the at least one single-phase AC / DC conversion unit of the three-phase power module that is turned off is configured to receive the AC voltage of a different phase of the three-phase AC voltage.

18. Each of the aforementioned power conversion devices, The power conversion system according to claim 11, further comprising a plurality of low-frequency ripple current suppression circuits, the same number as the number of three-phase power modules, and each of the three-phase power modules being connected to the output side.

19. Each of the low-frequency ripple current suppression circuits is: A first boost circuit having a first inductor, a first group of switches, and a first capacitor, A second boost circuit is connected to the first boost circuit and includes a second inductor, a second group of switches, and a second capacitor. Includes, The power conversion system according to claim 18, wherein each of the low-frequency ripple current suppression circuits receives the DC current having a ripple component and removes the ripple component via the first boost circuit and the second boost circuit.

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

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