WO2017098763A1

WO2017098763A1 - Power supply device and method for controlling initial charging thereof

Info

Publication number: WO2017098763A1
Application number: PCT/JP2016/076158
Authority: WO
Inventors: 泰明乗松; 叶田　玲彦; 馬淵　雄一; 尊衛嶋田; 充弘門田; 祐樹河口; 瑞紀中原; 輝米川
Original assignee: 株式会社日立製作所
Priority date: 2015-12-11
Filing date: 2016-09-06
Publication date: 2017-06-15
Also published as: JP2019041428A

Abstract

Reduction in size and weight is demanded of a transformer for system interconnection. By employing a SST for the transformer, reduction in size and weight can be achieved; however, reduction in size and weight is also demanded of a power supply for a control circuit, in addition to reduction in size and weight of the main-circuit transformer. There is also a need for reduction in size and weight of an initial charging circuit, which is necessary at the time of connecting a system as an input, and elements that are used need to be reduced in size and lowered in withstanding voltage. Provided is an initial charging circuit for a power conversion device, wherein: an LLC converter including an LLC transformer capable of insulation against system voltage is employed in a main circuit; a transformer for initial charging is connected to the secondary side of the LLC transformer; the initial-charging transformer drives at around a few tens of volts; and a low-voltage semiconductor element is used in a control circuit.

Description

Power supply device and its first charge control method

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 with a conventional insulation 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, there are some power converters that use high voltage power, such as for high voltage motors and pumps, and railways, that use a high voltage isolation 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 miniaturized including a function of suppressing inrush current and a method for controlling the initial charge thereof.

In order to solve the above problems, in the present invention, a first inverter unit that is connected to a power source via a switch and converts a DC input from a first capacitor to a high frequency and gives the output, and an output of the first inverter unit A power supply device comprising a main circuit composed of a transformer connected to the side, a rectifier unit for rectifying the output of the transformer, and a second capacitor provided on the output side of the rectifier unit, The apparatus is connected to a low-voltage DC power source for applying a DC voltage, an initial charging inverter unit that converts the output of the low-voltage DC power source into a high frequency, and an output side of the initial charging inverter unit. An initial charging circuit including an initial charging transformer connected to the secondary side is provided.

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 charging circuit as a whole can be reduced in size and weight, so that a high-voltage power converter can be reduced in size and weight.

1 is a diagram illustrating a configuration of a power supply device according to a first embodiment. The figure which shows the normal output power flow in the structure of the power supply device of FIG. 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. FIG. 6 is a diagram illustrating a configuration of a power supply device according to a second embodiment. FIG. 6 is a diagram illustrating a configuration of a power supply device according to a third embodiment. FIG. 10 is a diagram illustrating a configuration of a power supply device according to a fourth embodiment. FIG. 10 is a diagram illustrating a configuration of a power supply device according to a fifth embodiment.

Hereinafter, an embodiment of a power supply device and an initial charge control method thereof according to the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of the power supply device according to the first embodiment. The power supply device according to the embodiment has a configuration in which an input is connected to an AC system and a low-voltage DC is connected to an output. Note that the output low-voltage direct current may be further converted into alternating current at the subsequent stage and output.

1, the main circuit 10 is configured using a full-bridge type LLC resonant converter. The main circuit 10 using a full-bridge type LLC resonant converter is connected to the input terminal Ti through an switch CB and a current suppressing coil L1 to an AC system, and provides a DC output to the output terminal To of the main circuit 10.

The main circuit 10 using a full-bridge type LLC resonant converter includes, from the input side, a first rectifier unit R1, a smoothing capacitor C1, a first inverter unit In1, an LLC transformer 3, and a second rectifier unit. R2 and a smoothing capacitor C2. 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.

In the configuration of the main circuit 10, the first inverter unit In1 has a single-phase full bridge configuration, and the semiconductor elements H1, H2, H3, and H4 are configured by MOS-FETs.

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 direct current in the second rectifier section R2 and then output to the output terminal To.

As described above, in the first embodiment, the circuit configuration of the full-bridge type LLC resonant converter is applied to the subsequent stage of the first rectifier unit R1 (single-phase converter) composed of the semiconductor elements Q1, Q2, Q3, and Q4. 2 is configured to output a direct current output after full-bridge diode rectification by two rectifier units R2. In the first embodiment, a single-phase converter is assumed as the first rectifier unit R1, but it may be applied to a three-phase converter. The output is a direct current, but an inverter (second inverter unit In2) may be added to the subsequent stage to obtain an alternating current output.

In the power supply device of the present invention, the initial charging circuit 20 is connected to the secondary winding side of the LLC transformer 3 of the main circuit 10. The initial charging circuit 20 includes a low-voltage DC power source 21, an initial charging inverter unit 22, and an initial charging transformer 23. The DC voltage of the low-voltage DC power source 21 is converted into an AC voltage by the initial charging inverter unit 22, The smoothing capacitors C1 and C2 are charged via the charging transformer 23. The capacitors C1 and C2 are charged from the time before the switch CB is turned on, and the connected state may be maintained even after the power supply device is operated. As a result, since the inrush current flowing through the power supply device by turning on the switch CB is charged by the smoothing capacitors C1 and C2, only the amount corresponding to the difference voltage flows, so that the inrush current is suppressed.

Moreover, in the power supply device of the present invention, the second inverter unit In2 is provided in the subsequent stage of the second rectifier unit R2, and when the direct current is converted into the alternating current and then the alternating current is output to the output terminal To, the second inverter unit Is connected to the secondary winding side of the LLC transformer 3 of the main circuit 10 for supplying the gate power of the semiconductor elements Q5, Q6, Q7, Q8 and the power of the control circuit for generating the gate signal. Good.

1, the power supply circuit 17 obtains power from the secondary winding 34 of the LLC transformer 3 via the control circuit power supply transformer 4. In the illustrated example, the control circuit power transformer 4 includes a primary winding 41 and a secondary winding 42 electromagnetically coupled to the primary winding 41. The secondary winding 42 supplies DC power to the power supply circuit 17 via the single-phase bridge rectifier circuit 16. The DC power of the power supply circuit 17 is used as gate power given to the gates of the semiconductor elements Q5, Q6, Q7, Q8 of the second inverter unit In2 or control circuit power.

Further, voltage dividing resistors R1 and R2 are connected in series on the output side of the single-phase bridge rectifier circuit 16, and the connection point potential is used as a detection signal for the DC voltage Vdc of the main circuit.

According to this configuration, since the LLC transformer 3 operates at a high frequency, the device configuration can be reduced in size. Since the control circuit power transformer 4 also operates at a high frequency, it can be miniaturized. Further, the voltage dividing circuit for detecting the main circuit DC voltage Vdc is also lower in potential than the case where it is installed in the main circuit and is insulated, so that the circuit is miniaturized.

In this figure, the power supply circuit 17 supplies the gate power of the MOS-FET semiconductor elements Q5, Q6, Q7, and Q8 constituting the second inverter unit In2 and the power supply for the gate control circuit. The power supply circuit for one inverter unit In1 is not shown. A power supply circuit for the first inverter unit In1 is separately installed but is not described here. The reason for this is that the voltage level to be insulated (usually about 100 volts AC) is low on the first inverter unit In1 side, so that a high degree of insulation measure that is applied to the power supply circuit 17 is not required. This is because it can be handled by technology.

In the configuration of FIG. 1, the DC voltage Vd2 provided by the full-bridge type LLC resonant converter is a DC voltage of 1000 V or less, and therefore 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 the normal output power flow of Fig. 1. 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 dead time. It is assumed that the resonance frequency is determined by the values of the excitation inductance Lm, the leakage inductance Lr, and the resonance capacitor Cr, and is set to several tens to several hundreds kHz.

The control of the LLC resonant converter is executed by a control circuit that controls on / off of four sets of semiconductor elements constituting 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, the upper right and lower left semiconductor elements H3 and H2 in FIG. 1 are the first set, and the lower right and upper left semiconductor elements H1 and H4 are the second set. The first conductive state in which the first set is ON and the second set is OFF, and the second conductive state in which the second set is ON and the first set is OFF are alternately formed. The ON / OFF control is performed with a drive frequency having a period from the first conduction state to the first conduction state again through the second conduction state.

3, 4, and 5, the magnitude relationship between the LLC resonance frequency and the drive frequency, and the relationship between the voltage and current waveform of the first inverter unit In <b> 1 will be described. 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 side 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 OFF, the current flowing through the MOS-FET peaks out and is kept low enough, and the switching loss when OFF is also small. Therefore, high-efficiency 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.

In a state where the drive frequency is lower 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 equal to 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 is sufficiently low and leveled off after peaking out when it is OFF, the switching loss when OFF is small as with resonant frequency driving.

When the LLC resonance frequency is controlled to be higher than the drive frequency by the LLC control, the secondary side voltage 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 the 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 equal to 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, 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 the same as in the LLC resonant converter 1. There is no need for a DC reactor.

The above three operation modes in the 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.

FIG. 6 shows a power flow during charge control according to the present invention. In this power flow, the second capacitor C2 is charged from the low-voltage DC power source 21 through the initial charging inverter unit 22 (low-voltage full-bridge MOS FET), the initial charging transformer 23, 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 23, 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 charging circuit 20 even when the main circuit is not connected to the AC power source and power is not obtained from the outside.

In this power flow formation, the initial charge control is performed by inputting a duty 50% rectangular wave from the secondary side of the LLC transformer 3 in the first charge inverter unit 22 (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.

Fig. 7 shows the frequency difference in the initial charge control. 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.

FIG. 8 shows the configuration of the power supply device according to the second embodiment.

Example 2 is a configuration in which a suppression reactor L2 is added in addition to the current suppression control at the start of initial charging using the circuit configuration of FIG. 1 shown in Example 1, for example. Since the initial charging inverter unit 22 performs high-frequency driving that is equal to or higher than the LLC resonance frequency at the start of the initial charging, the current suppressing effect at the start of the initial charging can be obtained in the first embodiment or more. In addition, although the reactor L2 is used in FIG. 8, you may use resistance. In addition, an impedance component inside the initial charging transformer 23 may be used, or any component that can obtain the same effect may be used.

In the second embodiment, similarly to the first embodiment, the initial charging transformer 23 is connected to the secondary side of the LLC transformer 3 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.

FIG. 9 shows the configuration of the power supply device according to the third embodiment.

The third embodiment has a multi-level configuration in which outputs of a plurality of main circuits 10 are connected in series, and is configured to step down from the system voltage and connect the output side of the main circuit 10 in parallel to increase the output voltage. . The multi-level configuration may be a single phase as shown in FIG. 9, or may be a three-phase connection configuration of Δ connection or Y connection.

In addition, about the charge of the system side capacitor | condenser C2 of each LLC converter, the structure connected to the secondary side of the LLC transformer 22 similarly to Example 1, 2 is employ | adopted.

In addition, since the LLC transformer 3 has an insulation function in multiple levels, the first charging circuit 20 has an advantage that an insulation function for the system is not required.

In the third embodiment, similarly to the first and second embodiments, the first charging transformer 23 is connected to the secondary side of the LLC transformer 3, thereby reducing the size by using the low-voltage drive element, controlling the initial charging by the frequency, and increasing the frequency. It becomes possible to satisfy the downsizing of the initial charging transformer, and the power supply as a whole can be reduced in size and weight.

FIG. 10 shows the configuration of the power supply device according to the fourth embodiment.

Example 4 is a multi-level configuration in which outputs of a plurality of main circuits 10 are connected in series, and is configured to step down from a system voltage and output in parallel. Further, the charging of the system side capacitor C2 of each LLC converter is connected to the secondary side of the LLC transformer 3 and controlled as in the other embodiments.

Further, in the fourth embodiment, the effect of miniaturization in which only one control circuit is controlled can be obtained by making the first charging transformer 22 connected to the LLC transformer 3 have multiple outputs. Specifically, a plurality of windings (secondary windings) on the LLC transformer 3 side of the initial charging transformer 22 are provided, and these secondary winding sides are connected to the secondary winding side of the LLC transformer 3 of the different main circuit 10. Connected. Also in this configuration, since the LLC transformer 3 has an insulating function, there is an advantage that the initial charging circuit 20 does not need an insulating function for the system.

In the fourth embodiment, as in the other embodiments, the initial charging transformer 23 is connected to the secondary side of the LLC transformer 3 to reduce the size by using the low-voltage drive element, to control the initial charging by the frequency, and to increase the initial frequency by increasing the frequency. It becomes possible to satisfy the size reduction of the charging transformer, and the power supply device as a whole can be reduced in size and weight.

FIG. 11 shows the configuration of the power supply device according to the fifth embodiment.

Example 5 is a multi-level configuration in which outputs of a plurality of main circuits 10 are connected in series, and is configured to step down from a system voltage and output in parallel.

The charging of the system side capacitor C2 of each LLC converter is connected to the secondary side of the LLC transformer 3 and controlled as in the other embodiments. Furthermore, by switching the connection destination of the initial charging transformer 22 connected to the LLC transformer 3 with the switching relay 40, the effect of miniaturization of controlling the initial charging transformer 22 and the control circuit with only one can be obtained. Also in this configuration, since the LLC transformer has an insulating function, there is an advantage that the initial charging circuit does not need an insulating function for the system.

In the fifth embodiment, as in the other embodiments, the initial charge transformer 23 is connected to the secondary side of the LLC transformer 3 to reduce the size by using the low-voltage drive element, to control the initial charge by frequency, and to increase the initial frequency by increasing the frequency. It becomes possible to satisfy the size reduction of the charging transformer, and the power supply device as a whole can be reduced in size and weight.

Although many examples have been described above, the contents described in the examples may be combined as appropriate according to the application.

Through the above embodiments, in the present invention, the initial charging circuit 20 at high frequency is connected to the secondary winding side of the LLC transformer 3 and the capacitors C1 and C2 are initially charged, so Inrush current can be suppressed.

Regarding the initial charge control method using the initial charge circuit 20, the initial charge is performed by applying a high-frequency current to the secondary winding side of the LLC transformer 3 in a stage before connection to the AC system. The high frequency applied to the secondary side of the LLC transformer is changed from a high frequency to a low frequency according to the initial charge voltage.

Here, a circuit is formed via a parallel diode of a semiconductor element constituting the first inverter unit In1, and the capacitor C1 is initially charged. Further, after the power supply is connected, special disconnect control for the initial charging circuit 20 is unnecessary, and it may be left as it is. When the power supply circuit 13 is juxtaposed as shown in FIG. 1, the initial charge transformer 23 has a capacity different from that of the control circuit power supply transformer 4, so that it is preferable to arrange them separately.

In addition, in the power supply device according to the present invention described above, an example in which power is obtained from an AC system and DC or AC output is described has been described. This is because the main purpose was to alleviate the inrush current when connecting to the AC system. For example, when a solar power generation device is connected as DC input, the DC voltage is gradually generated and rises at dawn if it is connected at night when power generation is not performed. This is because there is no fear of inrush current. Therefore, when connecting with direct-current power supplies other than a solar power generation device is assumed, it cannot be overemphasized that this invention is applicable similarly.

CB: Switch, L1, L2: Reactor, 10: Main circuit, R1, R2: Rectifier part, In1, In2: Inverter part, 3: LLC transformer, 20: Initial charging circuit, 13: Power supply circuit, 21: Low voltage DC power supply , 22: Inverter section for initial charging, 23: Initial charging transformer

Claims

A first inverter unit that is connected to a power source via a switch and converts the DC input from the first capacitor to a high frequency, and a transformer connected to the output side of the first inverter unit; A power supply device configured to include a main circuit composed of a rectifier unit that rectifies an output and a second capacitor provided on the output side of the rectifier unit,
The power supply device is connected to an output side of the low-voltage DC power supply for applying a DC voltage, an initial charging inverter unit for converting the output of the low-voltage DC power source into a high frequency, and an output side of the initial charging inverter unit. A power supply device comprising: an initial charging circuit configured by an initial charging transformer for connecting a power source to a secondary side of the transformer.
The power supply device according to claim 1,
The transformer is an LLC transformer in which a reactor and a capacitor are arranged in series with a primary winding of the transformer.
The power supply device according to claim 1 or 2, wherein
The power supply apparatus according to claim 1, wherein the first inverter unit includes a full bridge circuit including a semiconductor element including a parallel diode.
The power supply device according to any one of claims 1 to 3,
The power supply device includes a second inverter unit that converts the output of the second capacitor into an alternating current of commercial frequency,
A control circuit power transformer connected to the secondary winding of the transformer; a rectifier circuit connected to the secondary side of the control circuit power transformer; and direct current power of the rectifier circuit to the second inverter unit A power supply device comprising a gate power supply including a power supply circuit used as gate power applied to a gate of a semiconductor element to be configured or power for control circuit.
The power supply device according to any one of claims 1 to 4,
A power supply device comprising a reactor in a circuit connecting a secondary side of the initial charging transformer and a secondary side of the transformer.
The power supply device according to any one of claims 1 to 5,
The power supply apparatus according to claim 1, wherein the plurality of main circuits are increased in voltage by connecting their output sides in series.
The power supply device according to claim 6,
A power supply apparatus comprising the initial charging circuit for each of the plurality of main circuits.
The power supply device according to any one of claims 1 to 5,
The main circuit has a large current by connecting its output sides in parallel, and the power supply device is characterized in that:
The power supply device according to claim 8, wherein
A power supply apparatus comprising the initial charging circuit in common for each of the plurality of main circuits.
The power supply device according to claim 9,
The initial charging transformer of the initial charging circuit provided in common includes a plurality of secondary windings, and each secondary winding is provided on the secondary side of the transformer of the plurality of main circuits. A power supply device characterized by being connected.
The power supply device according to claim 9,
The initial charging transformer of the first charging circuit provided in common has its secondary winding output switched and connected to the secondary side of the transformers of the plurality of main circuits. apparatus.
A first inverter unit that is connected to a power source via a switch and converts the DC input from the first capacitor to a high frequency, and a transformer connected to the output side of the first inverter unit; An initial charge control method for a power supply device configured to include a main circuit composed of a rectifier unit that rectifies an output and a second capacitor provided on the output side of the rectifier unit,
An initial charge control method for a power supply device, characterized in that a direct current is converted into a high frequency and applied to a secondary side of the transformer.
An initial charge control method for a power supply device according to claim 12,
An initial charge control method for a power supply apparatus, wherein a high frequency applied to a secondary side of the transformer is changed from a high frequency to a low frequency according to an initial charge voltage.