JP2017147812A - Power supply device and its first charge control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power supply and an initial charge control method therefor, which can be miniaturized while including a function for suppressing an in-rush current.SOLUTION: An electric power supply sequentially comprises: a first capacitor for smoothing; a first inverter part; a LLC transformer; a second rectifier part; and a secondary capacitor for smoothing from an input side to an output side, and comprises: an initial charging transformer on a primary side or a secondary side of the LLC transformer; and a main circuit constructed by parallelly connecting an initial charging output switch. At first, the first and second capacitors are charged in the main circuit connected to a neutral point of a Y-connection line three-phase circuit from an initial charging electric supply circuit. After the charging, the first and second capacitors in the main circuit on a high voltage side adjacent to the main circuit are charged. After that, the first and second capacitors in the main circuit on the high voltage side adjacent to the main circuit are sequentially charged.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply apparatus that performs power conversion for direct current power and alternating current power, and an initial charge control method thereof.

  Many isolation transformers are used in the power system, but it is difficult to reduce the size and weight because it is driven at a low frequency of several tens of Hz (50/60 Hz in Japan). There was a problem.

  On the other hand, by adopting SST (Solid State Transformer: hereinafter simply referred to as SST) technology that has been studied for application to high-voltage and high-power applications in recent years, it is expected to contribute to reduction in size and weight. ing. The SST is composed of a high-frequency transformer and a power conversion circuit, and the output or input of the SST is AC power having the same frequency as the conventional one. In SST, a high frequency is generated by a power conversion circuit (DC / DC converter or inverter) and a high frequency transformer is driven to connect an input or output to an AC power system having the same frequency as the conventional one. It replaces the isolation transformer. According to this configuration, the high-frequency transformer can be driven at a high frequency of several tens to several hundreds of kHz, so that a significant reduction in size and weight can be realized as compared to a conventional insulating transformer alone.

  For example, as a new application of power converters for power systems, high-performance power conversion that controls the power of natural energy and outputs it to the power system with the global expansion of natural energy introduction such as solar power generation and wind power generation. PCS (Power Conditioning System: hereinafter simply referred to as PCS) is required. Since the PCS is connected to the power system and used, a high-voltage insulation transformer is used on its output side, and it must be driven at a low frequency of several tens of Hz, which is the same as the frequency of the power system. There is a problem that the equipment becomes larger.

  In addition to power grid interconnections, for example, power converters that use high voltage power such as for high voltage motors and pumps, railways, etc., use a high voltage insulation transformer on the input side. Even when the output side is the same as the output side, the high voltage isolation transformer is driven at a low frequency of several tens of Hz that is the same as the frequency of the power system by receiving power from the power system. Have

  By adopting the SST concept, it is possible to realize with a miniaturized device in expanding the application to these power applications. Even in a power supply device employing such an SST concept, it is necessary to reduce the inrush current flowing through the power supply device when connected to an AC input as in a normal power supply device. It is necessary to install a charging current suppression circuit on the input side.

Japanese Patent Laid-Open No. 5-48479

  In order to realize SST to reduce the size and weight of the power converter that steps down from the high-voltage system, it is necessary to insulate between the system side and the low-voltage side. Therefore, an initial charge suppression circuit that suppresses the charging current to the capacitor on the system side SST when connecting to the system is required. For example, when connecting to a 6.6 kV system, an initial charging resistor and an initial charging relay are required in addition to the main transformer. Since the equipment required for the initial charging needs to be compatible with 6.6 kV, there is a problem that the power supply using the power converter becomes large.

  In view of the above, an object of the present invention is to provide a power supply apparatus that can be reduced in size, including the function of suppressing inrush current, and an initial charge control method thereof.

  In the present invention, the first capacitor for smoothing, the first inverter unit, the LLC transformer, the second rectifier unit, and the second smoothing unit are sequentially applied from the input side to the above problems. A power supply device comprising a main circuit configured by connecting a first charge transformer and an initial charge output switch in parallel on a primary side or a secondary side of an LC transformer. is there.

  In the present invention, the first and second capacitors in the main circuit connected to the neutral point of the Y-connected three-phase circuit are charged from the initial charging power supply circuit first, and the high voltage adjacent to the main circuit is charged after the charging. The first and second capacitors in the main circuit on the side are charged, and then the first and second capacitors in the main circuit on the high voltage side adjacent to the main circuit are sequentially charged. This is the first charge control method.

  According to the present invention, insulation from the system can be ensured, and a small initial charge control circuit can be obtained. Furthermore, according to the embodiment of the present invention, the volume of the initial charging transformer is reduced by increasing the frequency input to the initial charging transformer. In addition, a low-voltage element can be used as an element for driving the initial charge transformer. As a result, the first charge power supply circuit as a whole can be reduced in size and weight, so that the power converter for high voltage can be reduced in size and weight.

The figure which shows the structural example of the power supply device which concerns on Example 1 of this invention. The figure which shows the detailed structural example of the main circuit 10 comprised by SST. The figure which shows a voltage and electric current waveform when LLC resonant frequency is equal to a drive frequency. The figure which shows the voltage and electric current waveform when LLC resonance frequency> drive frequency. The figure which shows a voltage and electric current waveform at the time of LLC resonance frequency <drive frequency. The figure which shows the power flow at the time of charge control in the structure of the power supply device of FIG. The figure which shows the difference in the frequency in initial charge control. The figure which shows the view of the charge control to the high voltage | pressure side main circuit implemented between several main circuits. The figure which shows the structural example of the power supply device which concerns on Example 2 of this invention.

  Embodiments of a power supply apparatus and an initial charge control method thereof according to the present invention will be described below with reference to the drawings.

  FIG. 1 shows a configuration example of a power supply device according to Embodiment 1 of the present invention. In the power supply device of the present invention, the input side or the output side of a plurality of main circuits 10 configured by SST are connected in series to form each phase of a Y-connected three-phase circuit. FIG. 1 shows an example in which the input side is Δ-connected and the output side is Y-connected. An example in which the input side is Y-connected will be described later as a second embodiment.

  The power supply device of FIG. 1 connects the input sides of a plurality of main circuits 10 composed of SSTs in series to form each phase of a Δ-connected three-phase circuit, and outputs the plurality of main circuits 10 composed of SSTs. Are connected in series to form each phase of the Y-connected three-phase circuit. The configuration of the first embodiment is a configuration in which the input is connected to the system, the output is connected to a high voltage load such as a high voltage motor, the input side is Δ connection, and the output side is Y connection. Although it is assumed that the main circuit 10 composed of SST is connected to 6.6 kV in eight or six stages, of course, the number of stages is not limited to this, and the number of stages and the withstand voltage can be changed by changing the number of stages. It is also possible to raise and lower to 3 kV, 11 kV, and the like. Although not shown, it is preferable to add an input filter and an output filter as appropriate.

  FIG. 2 shows a detailed configuration example of the main circuit 10 configured by SST. The main circuit 10 is configured using a full-bridge type LLC resonant converter, and sequentially from the input terminal Ti side, a first rectifier unit R1, a smoothing capacitor C1, a first inverter unit In1, The circuit includes an LLC transformer 3, a second rectifier unit R2, a smoothing capacitor C2, and a second inverter unit In2. Here, the LLC transformer 3 is a transformer primary winding side of a first reactor 31, a second reactor 32 as a primary winding, and a capacitor 33 arranged in series. It is a vessel. FIG. 2 illustrates the main circuit 10a on the neutral point N side in the Y-connected three-phase circuit among the plurality of main circuits, but the other main circuits 10 have basically the same configuration.

  In the configuration of the main circuit 10, the first rectifier unit R1 has a single-phase full-bridge configuration, the semiconductor elements Q1, Q2, Q3, and Q4 are configured by MOS-FETs, and the first inverter unit In1 is In this example, a single-phase full-bridge configuration is used, and the semiconductor elements H1, H2, H3, and H4 are configured by MOS-FETs. The second rectifier section R2 has a single-phase full-bridge configuration with a diode, and the second inverter section In2 has a single-phase full-bridge configuration. The semiconductor elements S1, S2, S3, and S4 are connected to the MOS− An example of an FET is shown.

  According to the configuration of the main circuit 10, the first rectifier unit R1 converts the power of the AC system into DC, the first inverter unit In1 converts the DC into high-frequency AC, and the LLC transformer 3 arbitrarily And then converted to a direct current in the second rectifier section R2, and then converted to an alternating current having a frequency as appropriate in the second inverter section In2 and output to the output terminal To.

  Further, the main circuit 10 in FIG. 2 is provided with an initial charge transformer 1 and an initial charge output switch 2 for branching from the connection point between the LLC transformer 3 and the second rectifier unit R2 for the initial charge process. As shown in FIG. 1, these initial charging processing units perform initial charging of the main circuit 10 a on the neutral point N side in the Y-connected three-phase circuit among the plurality of main circuits 10 configured in a multistage product. The transformer 1 is connected to the initial charging power supply circuit 20, and the initial charging output switch 2 is connected to the initial charging transformer 1 of the main circuit 10b on the high voltage side adjacent to the neutral point N side in the Y-connected three-phase circuit. The subsequent adjacent main circuits 10 are sequentially connected by a low voltage side initial charge transformer 1 and a high voltage side initial charge output switch 2.

  Thus, in the power supply device of the present invention, the initial charge power supply circuit 20 is connected to the secondary winding side of the LLC transformer 3 of the neutral point side main circuit 10a via the initial charge transformer 1. The initial charging power supply circuit 20 includes a low voltage DC power supply 21 and an initial charging inverter unit 22. The DC voltage of the low voltage DC power supply 21 is converted into an AC voltage by the initial charging inverter unit 22, and the initial charging transformer 1 is converted. The capacitors C1 and C2 for smoothing are charged via these. The capacitors C1 and C2 are charged from the time before the voltage is applied to the input terminal Ti, and the connected state may be maintained even after the power supply device is operated. As a result, the inrush current that flows to the power supply device by applying a voltage to the input terminal Ti is charged by the smoothing capacitors C1 and C2, so that only the amount corresponding to the difference voltage flows, so that the inrush current is suppressed. ing.

  Further, after the charging of the capacitors C1 and C2 in the neutral point side main circuit 10a is completed, the capacitors C1 and C2 of the adjacent high-voltage side main circuit 10b are initially charged. 1 and a circuit formed by the initial charge output switch 2 on the high voltage side. The present invention is devised for the initial charging process on the high voltage side, and the detailed processing procedure will be described later.

  Hereinafter, the operation content of the power supply device according to the first embodiment of the present invention illustrated in FIGS. 1 and 2 will be described. First, the processing content in the normal operation state will be described, and then the initial charging process will be described. To do.

  In the configuration of FIGS. 1 and 2, since the DC voltage Vd2 provided by the full bridge type LLC resonant converter is a DC voltage of 1000 V or less, it is assumed that a MOS FET suitable for high frequency driving is applied. The switching frequency is assumed to be several tens kHz to several hundreds kHz. As the MOS FET to be used, a SiC MOS FET suitable for high withstand voltage and high frequency switching may be applied, and any other MOS FET having the same function may be used. The secondary side of the LLC resonant converter is assumed to be smoothed by a diode. In addition to Si diodes, Si-type Schottky barrier diodes and SiC Schottky barrier diodes may be applied to reduce conduction loss, and loss can be reduced by using SiC MOS FETs in synchronization. It may be any other one having the same function.

  Further, the LLC transformer 3 has an insulating function with respect to the system voltage, and in order to achieve LLC resonance, the leakage inductance Lr (first reactor 31) corresponding to resonance with the exciting inductance Lm (second reactor 32) of the high-frequency transformer. And a resonance capacitor Cr (capacitor 33). The leakage inductance Lr is assumed to be integrated in the high-frequency transformer as a structure capable of adjusting the constant of the leakage magnetic flux in the high-frequency transformer, but is not limited thereto. The resonance capacitor Cr is assumed to use a film capacitor or a ceramic capacitor, but may have any similar function.

  FIG. 2 shows a normal output power flow in the main circuit 10 of FIG. 1 as P1. Normally, the power flow is such that the DC voltage Vd1 rectified by the single-phase converter is output to Vd2 by a full-bridge type LLC resonant converter.

  In this case, the control of the LLC resonant converter is not PWM but frequency control of duty 50% with a dead time. The resonance frequency is determined by the values of the excitation inductance Lm, the leakage inductance Lr, and the resonance capacitor Cr described above, and is assumed to be set to several tens to several hundreds kHz.

  Note that the control of the LLC resonant converter is executed by a control circuit that controls on / off of the four sets of semiconductor elements H1, H2, H3, and H4 that constitute the full-bridge first inverter unit In1. The control circuit itself has a circuit configuration that is usually performed, and a specific circuit configuration is omitted. In short, the semiconductor element is controlled as follows.

  For example, among the four full-bridge semiconductor elements H1, H2, H3, and H4, the upper right and lower left semiconductor elements H3 and H2 in FIG. 2 are the first set, and the lower right and upper left semiconductor elements H1 and H4 are the first. In the case of two sets, the first conduction state in which the first group is ON and the second group is OFF, and the second conduction state in which the second group is ON and the first group is OFF Are controlled to be alternately formed, and ON / OFF control is performed with a driving frequency having a period from the first conduction state to the first conduction state again through the second conduction state. is there.

  The relationship between the LLC resonance frequency and the drive frequency and the voltage and current waveforms of the first inverter unit In1 will be described with reference to FIGS. In these figures, the horizontal axis represents time, and the vertical axis represents the magnitude of voltage and current during one cycle.

  FIG. 3 shows voltage and current waveforms when the LLC resonance frequency is equal to the drive frequency. In this case, the drive frequency is controlled by a control circuit that controls on / off of the four sets of semiconductor elements constituting the full-bridge first inverter unit In1, and the drive frequency is a high-frequency transformer. This coincides with the resonance frequency determined by the values of the excitation inductance Lm, leakage inductance Lr, and resonance capacitor capacitance Cr of a certain LLC transformer 3.

  In the state where the LLC resonance frequency is equal to the drive frequency, as shown in the waveform of the primary current ITin of the LLC transformer 3, when the MOS-FET which is a semiconductor element is ON, the current flowing through the MOS-FET is MOS- Since it flows in the reverse direction through the body diode of the FET, it becomes ZVS (zero volt switching), and no switching loss occurs when it is ON. When the MOS-FET is turned off, the current flowing through the MOS-FET is peaked out and suppressed sufficiently, and the switching loss at the time of turning off is also reduced. Therefore, highly efficient switching can be realized by LLC resonance control, and the power device is cooled. The device can be downsized.

  When the LLC resonance frequency is controlled to be equal to the drive frequency by the LLC control, the voltage on the secondary side of the LLC transformer 3 is VTout, and in short, a rectangular voltage output is obtained. Therefore, a rectangular wave voltage is input to the control circuit power transformer 4. For this reason, since the voltage corresponding to the turn ratio with respect to the terminal voltage Vdc of the second capacitor C2 is output to the secondary side output of the power transformer 4 for the control circuit, the voltage fluctuation is similar to the LLC resonant converter. There is no need for a DC reactor.

  FIG. 4 shows voltage and current waveforms when the drive frequency is lowered below the LLC resonance frequency and the boost operation is performed.

  When the drive frequency is lower than the LLC resonance frequency, as shown in the waveform of the primary current ITin of the LLC transformer 3, when the MOS-FET is ON, the current flowing through the MOS-FET is that of the MOS-FET. Since it flows in the reverse direction through the body diode, it becomes ZVS (zero volt switching) and no switching loss occurs when it is ON. At OFF, the current flowing through the MOS-FET is sufficiently low and kept flat after peaking out. Therefore, the switching loss at OFF is small as in the case of resonance frequency driving.

  When the LLC resonance frequency is controlled to be higher than the drive frequency by the LLC control, the voltage on the secondary side of the LLC transformer 3 becomes a rectangular wave voltage such as VTout. This rectangular wave voltage is a waveform with a slight delay between rising and falling with respect to the power transformer 4 for the control circuit, but basically a rectangular wave is input. For this reason, since the voltage corresponding to the turn ratio with respect to the terminal voltage Vdc of the second capacitor C2 is output to the secondary side output of the power transformer 4 for the control circuit, the voltage fluctuation is similar to the LLC resonant converter. There is no need for a DC reactor.

  FIG. 5 shows voltage and current waveforms when the drive frequency is raised above the LLC resonance frequency and the step-down operation is performed.

  In a state where the drive frequency is higher than the LLC resonance frequency, as shown in the waveform of the primary side current ITin of the LLC transformer 3, when the MOS-FET is ON, the current flowing through the MOS-FET is that of the MOS-FET. Since it flows in the reverse direction through the body diode, it becomes ZVS (zero volt switching) and no switching loss occurs when it is ON. Since the current flowing through the MOS-FET does not decrease at the time of OFF, the switching loss at the time of OFF increases. However, in the case of the control operation by the PCS, the reduction in efficiency can be minimized by limiting the voltage range for the step-down control.

  When the drive frequency is raised above the LLC resonance frequency by the LLC control, the voltage on the secondary side of the LLC transformer 3 is like VTout. In short, a rectangular voltage output is obtained. Therefore, a rectangular wave voltage is input to the control circuit power transformer 4. For this reason, since the voltage corresponding to the turn ratio with respect to the terminal voltage Vdc of the second capacitor C2 is output to the secondary side output of the power transformer 4 for the control circuit, the voltage fluctuation is the same as in the LLC resonant converter 1. There is no need for a DC reactor.

  The three operation modes in the above-described LLC control (LLC resonance frequency = drive frequency, LLC resonance frequency> drive frequency, LLC resonance frequency <drive frequency) are appropriately selected and executed in the actual operation scene of the power converter.

  Next, the initial charging process in the present invention will be described. First, initial charging for the neutral point side main circuit 10a will be described.

  FIG. 6 shows a power flow at the time of initial charge control for the neutral point side main circuit 10a. In this power flow, the second capacitor C2 is charged from the low voltage DC power source 21 via the first charging inverter unit 22 (low voltage full-bridge MOS FET), the initial charging transformer 1, and the second rectifier unit R2. Further, the first capacitor C1 is charged from the low-voltage DC power source 21 via the initial charging inverter unit 22 (low-voltage full-bridge MOS FET), the initial charging transformer 1, and the first inverter unit R1. The flow in this case is as illustrated in F1, F2, F3, and F4, but the flows F3 and F4 in the first inverter unit R1 are not performed by controlling the semiconductor elements H1, H2, H3, and H4. The semiconductor elements H1, H2, H3, and H4 are formed of parallel diodes. This means that the capacitors C1 and C2 can be initially charged only by the initial charge power supply circuit 20 even when the main circuit is not connected to the AC power supply and power is not obtained from the outside. .

  In forming this power flow, initial charge control is performed by inputting a rectangular wave of 50% duty from the secondary side of the LLC transformer 3 in the inverter unit 22 for initial charge (low voltage full bridge MOS FET). As described above, since the transformer voltage in the LLC control is a rectangular wave, the initial charge control is possible. Further, since the frequency of the rectangular wave is assumed to be a high frequency of about several tens of kHz that is the same as the frequency in the LLC control, the initial charge transformer can be miniaturized by increasing the frequency as in the LLC transformer.

  The difference in frequency in the initial charge control is shown in FIG. By changing the DC voltage Vd1 on the system side before and after the resonance frequency of the LLC, it becomes possible to change the DC voltage Vd1 in the direction opposite to the normal output. Therefore, in Example 1, it is assumed that the charging current is suppressed as a high frequency at the start of the initial charging, and the initial charging is completed until the DC voltage Vd1 is increased to a high voltage by further reducing the frequency after the resonance frequency is lowered. Of course, if there is no problem in the current value, control at a constant frequency may be used.

  From the above description, by connecting the initial charging transformer 1 to the secondary side of the LLC transformer 2, miniaturization by using a low-voltage drive element, control of initial charging by frequency, and miniaturization of the initial charging transformer by high frequency are satisfied. This makes it possible to reduce the size and weight of the entire power supply device.

  Thus, the initial charging process for the neutral point side main circuit 10a is performed. Next, the adjacent high voltage side first circuit is charged for the first time. In order to make this possible, in the present invention, in order to perform initial charging from the low-voltage side main circuit to the high-voltage side main circuit, an initial charging transformer 1 and an upper stage initial charging output switch 2 are provided in the main circuit. It has a configuration. In order to make the main circuit 10 configured by SST have a common configuration, the main circuit 10 includes the initial charge transformer 1 and the initial charge output switch 2 to the upper stage. The initial charge transformer 1 and the initial charge output switch 2 to the upper stage have a breakdown voltage equivalent to that of the semiconductor element used in the main circuit 10 because the main circuit 10 needs to have a breakdown voltage equivalent to one stage. On the other hand, the pressure can be reduced. Although the semiconductor element is represented by a MOS FET, the frequency characteristic is not required, and therefore an IGBT may be used as long as a similar function can be realized.

  FIG. 8 shows the concept of charge control for the high-voltage side main circuit implemented between a plurality of main circuits. As described above, after the initial charging of the first stage main circuit 10a is completed by the initial charging power supply circuit 20, the initial charging output switch 2 to the upper stage is turned on to start the second stage initial charging. Similarly, after the second stage initial charge is completed, the initial charge is completed up to the uppermost stage by repeatedly turning on the initial charge output switch 2 to the upper stage in the second stage main circuit 10b. Although not shown, the same initial charging process is performed on each of the U, V, and W phases of the Y connection, but they may be performed simultaneously or sequentially. The initial charge control circuit 20 may also be configured as a collective configuration for the U, V, and W phases, or may be configured as a divided configuration including one for each phase.

  As described above, by connecting the initial charging transformer 1 to the secondary side of the LLC transformer 3, miniaturization by using a low-voltage drive element, control of initial charging by frequency, and miniaturization of the initial charging transformer by high frequency are satisfied. This makes it possible to reduce the size and weight of the entire power supply device.

  In the first embodiment, the main circuit configuration in the case where the input side of the main circuit using SST is the Δ connection and the output side is the Y connection has been described. On the other hand, the second embodiment shown in FIG. 9 shows a configuration example in which the input side is Y-connected and the output side is Δ-connected, contrary to the first embodiment.

  Also in the case of the second embodiment, it is assumed that the main circuit 10 is connected in 8 or 6 stages to 6.6 kV, but of course, the present invention is not limited to this, and the number of stages and the withstand voltage can be changed. It is also possible to raise and lower to 3.3 kV, 11 kV, and the like. Although not shown, an input filter and an output filter can be added as appropriate. Also, in order to perform the initial charging in the upper direction by driving the initial charging power supply circuit 20 from the lowest limit near the neutral point on the Y connection side, an initial charging transformer 1 and an initial charging output switch 2 to the upper stage are provided. It is configured. In order to make the main circuit 10 have a common configuration, the main circuit 10 includes the initial charge transformer 1 and the output switch 3 to the upper stage. Since the initial charge transformer 1 and the output switch 3 to the upper stage need to have a withstand voltage equivalent to one SST stage, the withstand voltage is the same as that of the semiconductor element used in the main circuit 10, and the input / output voltage can be lowered. It becomes. The semiconductor element is represented by a MOS FET, but it may be an IGBT because frequency characteristics are not required, and any semiconductor device that can realize the same function may be used.

  However, since the input side is Y-connected in the second embodiment, the initial charge transformer 1 and the first charge output switch 3 to the upper stage are connected to the primary side of the LLC transformer 3 having the resonance capacitor. In the second embodiment, an initial charging transformer 1A is provided in the initial charging power supply circuit 20 separately from the main circuit 10. With this configuration, the breakdown voltage of the semiconductor element in the initial charge power supply circuit 20 can be made lower than that in the first embodiment.

  Note that the charging control can be realized by the same control as in the first embodiment even when connected to the primary side. In the second embodiment, similarly to the first embodiment, the initial charging transformer 1 is connected to the primary side of the LLC transformer 2 to reduce the size by using the low-voltage drive element, to control the initial charging by the frequency, and to perform the initial charging by increasing the frequency. The transformer can be miniaturized, and the entire power supply can be reduced in size and weight.

  Two examples have been described above. Of course, the contents described in the above examples may be used in combination depending on the application.

  In the third embodiment, the configuration of the main circuit 10 will be described. In the first and second embodiments, a full-bridge type LLC resonant converter is used, and sequentially from the input terminal Ti side, the first rectifier unit R1, the smoothing capacitor C1, the first inverter unit In1, and the LLC The description has been given on the assumption that the transformer 3 is configured by the second rectifier unit R2, the smoothing capacitor C2, and the second inverter unit In2.

  However, when the power supply circuit of the present invention is applied, the relationship between input and output is various. For example, in addition to the case of AC input and AC output, there may be a case of DC input, AC output, AC input, and DC output. Considering the circumstances of these application targets, the minimum standardized configuration of the main circuit 10 of the power supply circuit includes a smoothing capacitor C1, a first inverter unit In1, an LLC transformer 3, and a second rectifier unit. R2, a smoothing capacitor C2, an initial charge transformer 1, and an initial charge output switch 3 are provided, and a first rectifier unit R1 and a second inverter unit In2 are additionally installed depending on the application target, or It is preferable that the connection location of the initial charging transformer 1 and the initial charging output switch 2 is designed to be selectable on the primary side and the secondary side of the LLC transformer 3.

10: Main circuit R1, R2: Rectifier part In1, In2: Inverter part 1: Initial charge transformer 2: Initial charge output switch 3: LLC transformer 20: Initial charge power supply circuit 21: Low voltage DC power supply 22: Inverter part for initial charge

Claims (10)

  In order from the input side, the first capacitor for smoothing, the first inverter unit, the LLC transformer, the second rectifier unit, and the second capacitor for smoothing are provided to the output side, and the LLC A power supply apparatus comprising: a main circuit configured by connecting an initial charge transformer and an initial charge output switch in parallel on a primary side or a secondary side of a transformer. The power supply device according to claim 1,
A main circuit comprising one or both of a first rectifier section on the input side of the first capacitor for smoothing and a second inverter section on the output side of the second capacitor for smoothing A power supply apparatus comprising: The power supply device according to claim 1 or 2,
The initial charging transformer and the initial charging output switch are connected in parallel so as to be switchable to a primary side or a secondary side of the LLC transformer. The power supply device according to claim 2,
Either or both of the input side of the first rectifier unit and the output side of the second inverter unit are connected to each phase of a Y-connected three-phase circuit. The power supply device according to claim 4,
Each phase of the Y-connected three-phase circuit is formed by connecting in series the terminals on the input side of the plurality of main circuits or the terminals on the output side of the plurality of main circuits. . The power supply device according to claim 5,
The initial charge output switch in the main circuit on the neutral point side of the Y-connected three-phase circuit is connected to the LLC transformer of the main circuit on the high voltage side via the initial charge transformer of the main circuit on the high voltage side adjacent to the main circuit. A power supply device connected to the power supply. The power supply device according to claim 6, wherein
The power supply device, wherein the initial charging transformer in the main circuit connected to a neutral point of the Y-connected three-phase circuit is connected to an initial charging power supply circuit. The power supply device according to claim 7,
The initial charging power supply circuit includes a low-voltage DC power supply and an initial charging inverter unit, and outputs a high-frequency AC voltage. The power supply device according to any one of claims 1 to 8,
The first inverter unit provides a high-frequency alternating current output. An initial charge control method for a power supply device according to any one of claims 7 to 9,
First, from the initial charging power supply circuit, the first and second capacitors in the main circuit connected to the neutral point of the Y-connected three-phase circuit are charged, and after the charging, the high-voltage side adjacent to the main circuit A power supply device characterized in that the first and second capacitors in the main circuit are charged, and thereafter the first and second capacitors in the high-voltage side main circuit adjacent to the main circuit are sequentially charged. First charge control method.

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