JP6720056B2 - Power supply system and power supply - Google Patents

Description

The present invention relates to a power supply system including a plurality of power supply devices connected in parallel to a common load and a power supply device that constitutes the power supply system.

There are devices that require a large current exceeding 500 to 1000 A, such as arc welding machines and arc cutting machines. Patent Document 1 discloses a power supply device which is formed by connecting a plurality of switching converter circuits for AC/DC conversion of commercial alternating current in parallel and can output a large current to an arc welding machine. The operation of each switching converter circuit is controlled by one controller, and constitutes one power supply device as a whole. The controller detects the combined current output from each switching converter, and PWM-controls each switching converter circuit so that the detected current matches the target current.

JP 2001-129667A

However, a power supply device configured to output a large current with a single device as described above has various problems such as a heat resistant design that can withstand long-term operation and a safety design, and is generally expensive. is there. Therefore, it is considered that a plurality of power supply devices are connected in parallel to a common load and current is supplied from each power supply device to the load. Specifically, a power supply system has been considered in which power supply devices are connected by a communication line, a master power supply communicates with other slave power supplies, and the output of each power supply is centrally controlled. More specifically, the master power supply communicates with the slave power supplies to collect information on the output current of each slave power supply, and sends the PWM output width information calculated based on the collected information to each slave power supply. By doing so, the outputs of the respective power supplies are synchronized to perform PWM control in parallel.

By the way, in such welding power supply system, high-speed response of PWM output control is required, and each power supply device needs to perform high-speed communication. When other slave power supplies are directly connected to the main power supply, high-speed communication is possible, but it is necessary to provide communication ports as many as the other power supply devices, which causes a problem of high cost. On the other hand, when a plurality of other power supply devices are connected in series to the main power supply, the number of communication ports can be reduced to two. However, transmission and reception with the main power supply can be performed by the number of power supply devices connected in series. There is a problem in that the amount of information that is used increases and the response of communication decreases.

The present invention has been made in view of the above circumstances, and an object thereof is a power supply system including a plurality of power supply devices that are connected in parallel to a common load, each power supply while suppressing the number of communication ports. An object of the present invention is to provide a power supply system capable of realizing high-speed communication between devices and stably controlling an output current to a load, and a power supply device configuring the power supply system.

The power supply system according to the present invention includes a plurality of power supply devices connected in parallel to a common load, which are connected in series via a communication line, and control information for controlling a voltage or a current output to the load. Is a power supply system for controlling a voltage or a current output to the load by transmitting a first power supply device to a plurality of second power supply devices via the communication line. Includes a current detection unit that detects a current output from the device itself to the load, and a communication unit that transmits and receives current information related to the current output to the load, and communicates with the second power supply device at the end. The unit transmits current information indicating a current output from the device itself to the load to the non-terminal second power supply device, and the communication unit of the non-terminal second power supply device is the other terminal side device. Current information transmitted from the second power supply device, and current information relating to the sum of the current indicated by the received current information and the current output from the self device to the load is supplied to the first power supply device or The first power supply device transmits to the second power supply device on the side of the first power supply device, and the first power supply device detects the voltage output from the device itself to the load, and the voltage detection unit detects the voltage. Control information for controlling the voltage or current output to the load based on the information of the voltage, the current information received by the communication unit, and the information of the current detected by the current detection unit. And a calculation unit that calculates

In the present invention, the first and second power supply devices connected in parallel to a common load communicate with each other, and the first power supply device controls the output of the entire power supply system. Therefore, the current output from each power supply device to the load can be stably controlled.
Specifically, the first power supply device calculates control information for controlling the output to the load. Then, the first power supply device controls the output of its own device based on the calculated control information and transmits the control information to the second power supply device.
The second power supply device does not calculate the control information for controlling the output, receives the control information transmitted from the first power supply device, and automatically outputs the control information based on the control information calculated by the first power supply device. Control the output of the device. It should be noted that the plurality of second power supply devices connected in series sequentially transmit the control information from the first power supply device side to the end side, whereby each power supply device can receive the same control information.
Then, the second power supply device detects the current output from the device itself to the load, and sequentially transmits the detected current information to the first power supply device side from the end side. Specifically, the terminal second power supply device transmits current information indicating the current output from the self device to the load to the non-terminal second power supply device. The non-terminal second power supply device receives the current information transmitted from the terminal side, and based on the received current information and the information of the current output to the load by the device itself, the second power supply device of the terminal side includes the device itself. Current information relating to the sum of currents output from the power supply device to the load is obtained, and the current information is further transmitted to the first power supply device side. Hereinafter, similarly, each second power supply device sequentially transmits current information to the first power supply device side. Finally, the first power supply device receives current information related to the sum of the currents output from the plurality of second power supply devices connected in series to the load. Then, the first power supply device calculates the control information based on the current information and the current and voltage information output from the device to the load. The control information calculated here is calculated based on the current and voltage output from the first and second power supply devices, and is information that can control the output of the entire power supply system. Since the first and second power supply devices control the output based on the control information, the current output from each power supply device to the load is not unstable, and stable output control is possible. Will be possible. Further, each second power supply device is configured to collect the respective current information and transmit the current information to the first power supply device side, so that high-speed communication is possible and high-speed response of PWM output control is realized.

In the power supply system according to the present invention, the current information related to the sum transmitted from the second power supply device includes a plurality of the second power supply devices on the terminal side and the number of own devices, and the plurality of second power supply devices. It includes the average value of the current output from the power supply device and the device itself.

In the present invention, each second power supply device has the average number of currents output from its own device and the second power supply device on the terminal side and the current output from the second power supply device on the terminal side and its own device. The current information including the value and the value is transmitted to the first power supply device side. Therefore, the amount of current information can be reduced.

In the power supply system according to the present invention, the current information related to the sum transmitted from the second power supply device is obtained by adding the currents output from the plurality of second power supply devices on the terminal side and the own device. Including the obtained value.

According to the present invention, each of the second power supplies supplies current information including a value obtained by adding currents output to the load from the self-device and the second power supply on the terminal side to the first power supply. Send to the device side. Therefore, the amount of current information can be reduced.

In the power supply system according to the present invention, the communication unit includes a first communication unit and a second communication unit for connecting the plurality of power supply devices in series.

In the present invention, each power supply device can connect a plurality of power supply devices in series by connecting the first communication unit and the second communication unit with a communication line.

In the power supply system according to the present invention, the plurality of second power supply devices are respectively connected in series to the first communication unit and the second communication unit of the first power supply device.

In the present invention, the plurality of second power supply devices are serially connected to the first communication unit of the first power supply device, and the plurality of second power supply devices are also serially connected to the second communication unit. It Therefore, it is possible to reduce the number of second power supply devices connected in series and to connect more second power supply devices to the first power supply device.
For example, when three power supply devices are connected in series to each of the first communication unit and the second communication unit of the first power supply device, seven power supply devices are connected to each other. The number of second power supply devices connected in series to the device, that is, the number of layers can be suppressed to three. Therefore, the amount of current information transmitted and received can be suppressed, the first power supply device can perform high-speed communication with each second power supply device, and high-speed response of PWM output control can be realized.

A power supply device according to the present invention is a power supply device that receives control information for controlling voltage or current output to a load, and outputs voltage and current to the load based on the received control information. The other power supply device is connected, the first communication unit and the second communication unit for transmitting and receiving information to and from the power supply device, and a current detection unit for detecting a current output to the load, The second communication unit receives current information indicating the current output from the other power supply device connected to the second communication unit to the load, and the first communication unit detects the current indicated by the received current information. , And sends current information relating to the sum of the current output from the device itself to the load to the other power supply device connected to the first communication unit.

According to the present invention, it is possible to configure a power supply system capable of realizing high-speed communication between power supply devices and stably controlling an output current to a load while suppressing the number of communication ports.

A power supply device according to the present invention transmits control information for controlling a voltage or current output to a load to a plurality of other power supply devices, and controls a voltage or current output from each power supply device to the load. A current detection unit that detects a current output from the device to the load, a voltage detection unit that detects a voltage output from the device to the load, and the load from the other plurality of power supply devices. To the communication unit that receives the current information related to the sum of the currents output to the voltage detection unit, the information about the voltage detected by the voltage detection unit, the current information received by the communication unit, and the current detection unit. And a calculation unit that calculates control information for controlling the voltage or current to be output to the load, based on the information on the obtained current.

According to the present invention, it is possible to configure a power supply system capable of realizing high-speed communication between power supply devices and stably controlling an output current to a load while suppressing the number of communication ports.

According to the present invention, there is provided a power supply system including a plurality of power supply devices connected in parallel to a common load, which realizes high-speed communication between the power supply devices while suppressing the number of communication ports, and outputs to the load. The current can be controlled stably.

It is a block diagram showing an example of 1 composition of a power supply system concerning this embodiment. It is a conceptual diagram which shows the hierarchy of the some 2nd power supply device connected in series. It is a block diagram which shows one structural example of a power supply device. It is a flowchart which shows the process procedure of each power supply device which concerns on electric power feeding control. It is a flowchart which shows the process procedure of each power supply device which concerns on electric power feeding control. It is a flowchart which shows the process procedure of each power supply device which concerns on electric power feeding control.

Hereinafter, the present invention will be described in detail with reference to the drawings showing an embodiment thereof.
FIG. 1 is a block diagram showing a configuration example of a power supply system according to the present embodiment, and FIG. 2 is a conceptual diagram showing a hierarchy of a plurality of second power supply devices 1 connected in series. The power supply system according to the present embodiment includes a plurality of power supply devices 1 that are connected in parallel to a common load 2 related to arc welding and supply power to the load 2. The power supply devices 1 are connected in series by a communication line 3. The plurality of power supply devices 1 are insulation type switching power supplies, which AC/DC convert AC into required DC and supply AC 2 to the load 2.

Of the plurality of power supply devices 1, one power supply device 1 functions as a master power supply that controls the output of each power supply device 1 by transmitting PWM control information to another power supply device 1 via the communication line 3. .. The other power supply device 1 functions as a slave power supply that receives the PWM control information transmitted from the one power supply device 1 and controls the output based on the received PWM control information. Hereinafter, the power supply device 1 functioning as a master power supply will be appropriately referred to as a first power supply device 1, and the power supply device 1 functioning as a slave power supply will be referred to as a second power supply device 1.

Further, each power supply device 1 includes a communication unit 19c that transmits and receives various information to and from each other. The communication unit 19c includes a first communication unit 19d and a second communication unit 19e for connecting the plurality of power supply devices 1 in series. The first communication unit 19d and the second communication unit 19e have independent communication ports. A plurality of second communication devices are serially connected to the first communication unit 19d of the first power supply device 1. Specifically, the first communication unit 19d of the second power supply device 1 directly connected to the first power supply device 1 is connected to the first communication unit 19d of the first power supply device 1 via the communication line 3. Connected. The second communication unit 19e of the second power supply device 1 is connected to the first communication unit 19d of the other second power supply device 1 via the communication line 3. Hereinafter, similarly, the plurality of second power supply devices 1 are connected in series with each other. Similarly, a plurality of second communication devices are serially connected to the second communication unit 19e of the first power supply device 1.
Hereinafter, as shown in FIG. 2, the second power supply device 1 directly connected to the first power supply device 1 is the first layer, and the other second power supply device is connected to the second power supply device 1. The device 1 is called the second layer. Hereinafter, the second power supply device 1 connected in series in the same manner is referred to as a third layer, a fourth layer,... Nth layer. However, N is a natural number of 2 or more. In addition, a layer having a small number in a layer is called an upper layer, and a layer having a large number is called a lower layer.

The second power supply device 1 detects a current output from the device itself to the load 2, and transmits current information related to the detected current from the lower layer to the upper layer via the communication line 3 to the first power supply device 1. To do. Details of the current information will be described later. The first power supply device 1 receives the current information transmitted from the second power supply device 1, and outputs from the power supply system to the load 2 based on the current indicated by the current information and the current detected by the device itself. Calculate the total current applied. Then, the first power supply device 1 detects the voltage output from the device itself to the load 2, and outputs the power of each power supply device 1 constituting the power supply system based on the detected voltage and the total current. PWM control information for controlling the control signal is calculated. The first power supply device 1 controls the output of the device itself based on the PWM control information calculated in this way, and outputs the PWM control information from the upper layer to the lower layer as described above. To the power supply device 1 to control the operation of each power supply device 1.

As will be described later, by switching the operation mode, each power supply device 1 can function as either a master power supply or a slave power supply. Further, by switching the operation mode, it is possible to function as one independent power supply device 1.

FIG. 3 is a block diagram showing a configuration example of the power supply device 1. Since the configurations of the first and second power supply devices 1 are the same, the configuration of one power supply device 1 will be mainly described.

The power supply device 1 includes an operation panel 10, an input unit 11, a rectifier 12, an inverter 13, a transformer 14, a rectifying/smoothing unit 15, a voltage detecting unit 16, a current detecting unit 17, a main control unit 18, and a signal processing unit 19.

The input unit 11 is an input terminal connected to, for example, a three-phase AC power supply (not shown). The input unit 11 is connected to the rectifier 12, and the three-phase alternating current applied to the input terminal is input to the rectifier 12.

The rectifier 12 is, for example, a diode bridge circuit. The diode bridge has a circuit configuration in which three sets of series circuits (not shown) each including two diodes connected in sequence are arranged in parallel. A smoothing capacitor (not shown) is provided at the output end of the diode bridge circuit. The rectifier 12 full-wave rectifies the alternating current input from the three-phase alternating current power supply via the input unit 11 and outputs the direct current smoothed by the smoothing capacitor to the inverter 13.

The inverter 13 is a circuit that converts the direct current rectified and smoothed by the rectifier 12 into a high frequency alternating current and outputs it to the transformer 14. The inverter 13 is, for example, a full bridge circuit including four switching elements. The full-bridge circuit has a circuit configuration in which two pairs of legs formed by connecting two switching elements in series are connected in parallel. Each switching element is a power device such as an IGBT (Insulated Gate Bipolar Transistor) and a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor).

The transformer 14 transforms the alternating current output from the inverter 13 and outputs the transformed alternating current to the rectifying/smoothing device 15. The transformer 14 includes a primary coil and a secondary coil which are wound around a core and magnetically coupled to each other. The primary coil is connected to the inverter 13 and the secondary coil is connected to the rectifying/smoothing device 15.

The rectifying/smoothing device 15 is a circuit that rectifies and smoothes the alternating current output from the transformer 14, and the rectified direct current voltage and current are output to the load 2 from the positive output terminal 1a and the negative output terminal 1b. The rectifying/smoothing device 15 is composed of, for example, a full-wave rectifying circuit using a center tap, a smoothing circuit using a reactor, and the like.

The load 2 is related to, for example, arc welding, and the welding wire 21, the base material 22, the arc in which the shield gas is ionized, and the like serve as the load 2. The positive output terminal 1a is electrically connected to the welding wire 21 via the positive side power supply line and the welding torch 20, and the negative output terminal 1b is connected to the base material 22 via the negative side power supply line.

The voltage detection unit 16 is connected to, for example, the output side of the rectifying/smoothing unit 15, detects the voltage output from the self device to the load 2, and outputs a voltage value signal indicating the detected voltage value to the main control unit 18. This is the output circuit.

The current detection unit 17 is provided, for example, on the output side of the rectifying/smoothing unit 15, detects the current output from the device to the load 2, and sends a current value signal indicating the detected current value to the main control unit 18. This is the output circuit. The current detector 17 is, for example, a Hall-type current sensor including a magnetoelectric conversion element such as a Hall element.

The main control unit 18 is a processor having a CPU (Central Processing Unit), a ROM, a RAM, an interface, and the like, and controlling the operation of the entire power supply device 1. A control terminal 1c is connected to the interface of the main controller 18. The control communication line of the welding machine is connected to the control terminal 1c of the power supply device 1 that functions as a master power supply, and the drive instruction signal output from the welding machine is input. The main control unit 18 monitors the input state of the drive instruction signal, and when the drive instruction signal is input, outputs a drive request for operating the inverter 13 to the signal processing unit 19. The drive instruction signal is not input to the control terminal 1c of the power supply device 1 functioning as a slave power supply.
The voltage detection unit 16 and the current detection unit 17 are connected to the interface of the main control unit 18, and the voltage value signal and the current value signal are input. The main control unit 18 AD-converts the input voltage value signal and current value signal, and outputs voltage information and current information obtained by AD conversion to the signal processing unit 19.
Further, the main controller 18 is connected to the operation panel 10, and a signal according to an operation on the operation panel 10 is input. The main control unit 18 receives an operation on the operation panel 10 by monitoring the signal. The main control unit 18 according to the present embodiment can accept selection of the operation mode of the power supply device 1 on the operation panel 10. The operation modes include a master power supply mode (first control method) that causes the power supply device 1 to function as a master power supply, a slave power supply mode (second control method) that causes the power supply device 1 to function as a slave power supply, and a single power supply function to operate as a single power supply. There is a power mode. In addition, the main control unit 18 outputs a display instruction signal for displaying various operation states such as an operation mode, an output voltage, and an output current of the own apparatus to the operation panel 10, thereby the operation state of the own apparatus is displayed on the operation panel. Display on 10.
Furthermore, the main controller 18 of the power supply device 1 operating as the master power source outputs a wire feeding control signal for controlling the feeding of the welding wire 21 in the welding machine from the control terminal 1c to the welding machine. .. The power supply device 1 operating as a slave power supply does not output the wire feeding control signal.

The signal processing unit 19 is a DSP (digital signal processor) that outputs a PWM signal to a switching element that configures the inverter 13 and performs PWM control of on/off of the switching element, and includes a control information calculation unit 19a and a PWM control unit (control unit. ) 19b and the communication part 19c. The communication unit 19c has a first communication unit 19d and a second communication unit 19e. The signal processing unit 19 is connected to the inverter 13 and the main control unit 18, and the voltage information, the current information, the drive request, etc. output from the main control unit 18 are input to the signal processing unit 19. The signal processing unit 19 stores the operation mode of its own device, and its signal processing content differs depending on the operation mode of the power supply device 1. Details of the signal processing content will be described later.

The control information calculation unit 19a is a functional unit that controls the operation of the inverter 13 to calculate PWM control information for controlling the voltage or current output to the load 2. The PWM control information is information indicating the pulse width and pulse waveform of the PWM signal output to the inverter 13.
When the operation mode is the single power supply mode, the control information calculation unit 19a determines the inverter of its own device based on the voltage information and the current information output from the main control unit 18, that is, the voltage and the current detected by the own device. PWM control information for performing PWM control of 13 is calculated.
When the operation mode is the master power supply mode, the control information calculation unit 19a determines the first based on the voltage information and the current information of its own device output from the main control unit 18 and the current information of the other power supply device 1. PWM control information for PWM controlling the inverters 13 of the first and second power supply devices 1 is calculated. That is, the control information calculation unit 19a calculates the PWM control information based on the voltage and current detected by the device itself and the current detected by the other power supply device 1 that is the slave power supply. The current information detected by the other power supply device 1 can be received by the first communication unit 19d and the second communication unit 19e.
When the operation mode is the slave power supply mode, the control information calculator 19a does not calculate the PWM control information.

The PWM control unit 19b is a functional unit that uses the PWM control information to generate a PWM signal having a required pulse width and pulse waveform and output the PWM signal to the inverter 13. The PWM control unit 19b causes the inverter 13 to output an alternating current by alternately switching the switching elements of the full bridge circuit between the on state and the off state by crossing.
When the operation mode is the single power supply mode or the master power supply mode, the PWM control unit 19b uses the PWM control information calculated by the control information calculation unit 19a of its own device to generate the PWM signal.
When the operation mode is the slave power supply mode, the PWM control unit 19b uses the PWM control information calculated by the first power supply device 1 to generate the PWM signal. The PWM control information calculated by the first power supply device 1 can be received by the first communication unit 19d. When the own device and the other power supply device 1 have the same output capacity, the PWM signal of the own device and the PWM signal of the other power supply device 1 result in substantially the same signal. When the output capacities are different, the PWM control unit 19b generates a PWM signal in which the output capacity difference is corrected using the PWM control information calculated by the other power supply device 1. In this case, the PWM signal of its own device and the PWM signal of the other power supply device 1 are different signals.

The first communication unit 19d and the second communication unit 19e are communication circuits for transmitting and receiving various information to and from the other power supply device 1, and each have a communication port. The first communication unit 19d and the second communication unit 19e transmit and receive information according to, for example, HCI (Host Control Interface) communication standard. The power supply device 1 on the upper layer side is connected to the first communication unit 19d, and the power supply device 1 on the lower layer side is connected to the second communication unit 19e. The second communication unit 19e of the power supply device 1 at the end is an empty port, and the signal processing unit 19 of the power supply device 1 is located at the end because no signal is input to the second communication unit 19e. Can recognize that.
When the operation mode is the master power supply mode, the signal processing unit 19 operates the PWM control information calculated by the control information calculation unit 19a in the slave power supply mode via the first communication unit 19d and the second communication unit 19e. Is transmitted to another power supply device 1. The power supply device 1 operating in the slave power supply mode receives the PWM control information transmitted from the power supply device 1 operating in the master power supply mode at the first communication unit 19d. When the second power supply device 1 in a lower layer than the own device is connected, the signal processing unit 19 transmits the received PWM control information to the second power supply device 1 in a lower layer by the second communication unit 19e. Send. Further, the signal processing unit 19 operating in the slave power supply mode operates, in the master power supply mode, on current information related to the current output from the power supply device 1 in the lower layer of the device to the load 2 via the first communication unit 19d. It is transmitted to the power supply device 1 in the upper layer. The power supply device 1 that is the master power supply receives the current information transmitted from the power supply device 1 operating in the slave power supply mode in the first communication unit 19d and the second communication unit 19e.

The operation panel 10 includes a current display unit and a voltage display unit that show the current and voltage output to the load 2.
When the operation mode is the master power supply mode, the main control unit 18 causes the current display unit to display the value of the total current obtained by adding the currents output from the power supply devices 1. Further, the value of the voltage detected by the device itself is displayed on the voltage display unit. When the operation mode is the slave power supply mode, the main control unit 18 causes the current display unit and the voltage display unit to display predetermined information indicating that the device is being driven. The predetermined information is, for example, character information such as “during driving” or “RUN”, but the content of the information to be displayed is not particularly limited, and the display pixel or segment forming the current display unit and the voltage display unit is displayed. A configuration in which all lights or all lights are turned off is also included. When the operation mode is the single power supply mode, the main control unit 18 causes the current display unit and the voltage display unit to display the values of the current and the voltage output from the own device.

The operation panel 10 also includes an operation unit for switching the operation mode of the power supply device 1 and an operation mode display unit for displaying the current operation mode of the own device. The operation unit is, for example, a sealed tactile switch, push button switch, or the like. The main control unit 18 of the power supply device 1 switches the current operation mode to another operation mode when the operation unit is operated. For example, the signal processing unit 19 stores the current operation mode, and the main control unit 18 switches the operation mode of the signal processing unit 19 by outputting a mode switching instruction to the signal processing unit 19. The operation modes are switched in the order of, for example, a single power source mode, a master power source mode, a slave power source mode, a single power source mode...
The operation mode display unit has a plurality of light emitting elements. The plurality of light emitting elements include, for example, a light emitting element that lights up in the master power supply mode and a light emitting element that lights up in the slave power supply mode.

FIG. 4 to FIG. 6 are flowcharts showing the processing procedure of each power supply device 1 related to power supply control. Here, the processing of the first power supply device 1 operating in the master power supply mode and the two second power supply devices 1 connected in series to the power supply device 1 will be described. It should be noted that although there are two series of the plurality of second power supply devices 1 connected in series to the first power supply device 1, the operation of each system is the same, and therefore the operation of one system will be described here and the other system will be described. The description of the operation of the series is omitted.

When the drive instruction signal is input to the first power supply device 1 that is the master power supply, the main control unit 18 determines the current and voltage output from the device to the load 2 by the current detection unit 17 and the voltage detection unit 16. (Step S11). The main control unit 18 outputs the detected current information and voltage information to the signal processing unit 19.

The signal processing unit 19 in the master power supply mode calculates the PWM control information based on the current and the voltage indicated by the current information and the voltage information (step S12). At the time of startup, the slave power supply device 1 has not started operating, and therefore, for example, the PWM control information is calculated using the current and voltage detected by the first power supply device 1.
Then, the signal processing unit 19 performs PWM control of the inverter 13 based on the calculated PWM control information (step S13). Next, the signal processing unit 19 transmits the PWM control information to the second power supply device 1 that is the slave power supply via the first communication unit 19d and the second communication unit 19e (step S14).

The signal processing unit 19 of the power supply device 1 operating in the slave power supply mode receives the PWM control information transmitted from the first power supply device 1 at the first communication unit 19d (step S15). Then, the signal processing unit 19 in the slave power supply mode PWM-controls the inverter 13 of the own device based on the received PWM control information (step S16). Next, in the slave power supply mode, the signal processing unit 19 receives the PWM control information received in step S15 from the lower layer via the second communication unit 19e when the second power supply device 1 is connected to the lower layer than the own device. To the power supply device 1 (step S17).

The signal processing unit 19 of the second power supply device 1 in the lower layer receives the PWM control information transmitted from the second power supply device 1 in the upper layer at the first communication unit 19d (step S18). The signal processing unit 19 in the slave power supply mode PWM-controls the inverter 13 of the own device based on the received PWM control information (step S19).

Next, the main control unit 18 of the second power supply device 1 at the end detects the current output from its own device to the load 2 by the current detection unit 17 (step S20). The main controller 18 outputs the detected current information to the signal processor 19.

The current information transmitted from the second power supply device 1 to the upper first power supply device 1 or the second power supply device 1 includes the current output to the load 2 from the device itself and the power supply device 1 in a lower layer than itself. The average value I(T) and the number K(T) of the power supply devices 1 connected to itself and the lower layer are included. The average value I(T) and the number of units K(T) are represented by the following formula.
I(T)=
(I(T+1)×K(T+1)+Ifb(T))/(K(T+1)+1)...(1)
K(T)=K(T+1)+1...(2)
However,
Ifb(T): own output current I(T): average value of output current below layer T K(T): number of connected power supply devices 1 below layer T T: layer number N: bottom layer number I( T=N+1)=0
K (T=N+1)=0

The signal processing unit 19 of the power supply device 1 located at the end sets the number K (T=N)=1 of the power supply devices 1 and the current I (T=N)=Ifb(T) output from the self device to the load 2. The electric current information including is transmitted to the upper layer power supply device 1 via the first communication unit 19d (step S21).

The signal processing unit 19 of the non-terminal second power supply device 1 receives the current information transmitted from the terminal-side power supply device 1 at the second communication unit 19e (step S22). The main control unit 18 of the second power supply device 1 detects the current output from its own device to the load 2 by the current detection unit 17 (step S23). The main controller 18 outputs the detected current information to the signal processor 19. Then, the signal processing unit 19 calculates the average value of the currents output from its own device and the power supply device 1 in the layer lower than the own device by the above equations (1) and (2) (step S24). Then, the signal processing unit 19 determines the average value I(T) of the current output from the power supply device 1 in the lower layer of the self device and itself to the load 2, and the power supply device 1 connected to the lower layer of the self device and itself. The current information including the number of units K(T) is transmitted to the upper power supply device 1 via the first communication unit 19d (step S25).

The signal processing unit 19 in the master power supply mode that has transmitted the PWM control information and the like receives the current information transmitted from the second power supply device 1 (step S26). Then, in the signal processing unit 19, the main control unit 18 of the first power supply device 1 detects in the current detection unit 17 the current output from the self-device to the load 2 (step S17). S27). Then, the signal processing unit 19 loads the load from all the power supply devices 1 based on the current information detected by the current detection unit 17 and the current information received by the first communication unit 19d and the second communication unit 19e. The total sum of the electric currents output to 2 is calculated (step S28).

The total current Isum is represented by the following formula.
Isum=I1×N1+I2×N2+Ifb... (3)
However,
Isum: total current I1: average output current I2 in the first system connected to the first communication unit 19d: average output current N2 in the second system connected to the second communication unit 19e: to the first communication unit 19d Number of connected power supply devices 1 connected N2: Number of connected power supply devices 1 connected to second communication unit 19e Ifb: Output current of master power supply

Next, the main control unit 18 of the first power supply device 1 causes the voltage detection unit 16 to detect the voltage output from the device to the load 2 by the voltage detection unit 16 (step S29). Then, the signal processing unit 19 calculates the PWM control information based on the total current calculated in step S28 and the voltage detected by the device itself (step S30). The PWM control information calculated here is based on the current and voltage output from the entire power supply system to the load 2, and is information that can control the output of the entire power supply system.

Then, the main control unit 18 determines whether or not the drive instruction signal is continuously input (step S31). When it is determined that the drive instruction signal is not input (step S31: NO), the control of the inverter 13 by the signal processing unit 19 is stopped to stop the output to the load 2 (step S32), and the process is ended. When determining that the drive instruction signal is input (step S31: YES), the main control unit 18 returns the process to step S13 and continues the power supply control to the load 2.

In the power supply system configured as described above, the first power supply device 1 that is the master power supply acquires current information from the second power supply device 1 that is the slave power supply, and controls the output of each power supply device 1. PWM control information is calculated. Then, the first power supply device 1 transmits the calculated PWM control information to the second power supply device 1, and the power supply device 1 that is a slave power supply outputs based on the PWM control information calculated on the master power supply side. To control. Therefore, in the power supply system according to the present embodiment, the current output from each power supply device 1 to the load 2 can be stably controlled.

Further, since the power supply devices 1 are connected in series, the number of communication ports connecting the plurality of power supply devices 1 can be suppressed to two.

Further, since the lower layer power supply device 1 is configured to transmit the average current of the lower layer side and the number of connected devices to the upper layer, the amount of information communicated between the power source devices 1 can be suppressed, and the PWM output control High-speed response is realized.

Furthermore, the power supply device 1 according to the present embodiment can function as either a master power supply or a slave power supply by operating the operation unit. Therefore, even if the master power supply forming the power supply system fails, the power supply system can be easily reconstructed by switching the operation mode of the power supply device 1 functioning as the slave power supply to the master power supply mode.

Furthermore, the power supply device 1 according to the present embodiment can also function as a single power supply by operating the operation unit.

In the present embodiment, an example in which a plurality of power supply devices 1 are connected in series to the first communication unit 19d and the second communication unit 19e of the first power supply device 1 that is the master power supply has been described. A plurality of power supply devices 1 may be connected in series to either one of 19d and the second communication unit 19e. For example, two power supply devices 1 may be connected in series to the first communication unit 19d, and one power supply device 1 may be connected to the second communication unit 19e.

Although the load 2 related to arc welding has been described as the load 2, the load 2 may be used as a power supply system that supplies power to the load 2 that requires arc cutting or other large current.

Furthermore, the power supply system according to the present embodiment can output a large current to the arc welder.

Furthermore, in the present embodiment, an example in which the insulation transformer type switching power supply is PWM-controlled has been described, but the configuration and control method of the power supply device 1 are not particularly limited, and a known configuration and control method may be used. good. Known control methods include, for example, a pulse frequency modulation method in addition to the pulse width modulation method.

In the embodiment, the example in which the second power supply device 1 transmits the average value of the currents output from the self-device and the power supply device 1 on the lower layer side and the number of the power supply devices 1 on the lower layer side to the upper layer side has been described. Alternatively, the currents output from the self-device and the power supply device 1 on the lower layer side may be added, and the current information indicating the current value obtained by the addition may be transmitted to the upper layer side.

Further, although the example in which each power supply device 1 is provided with two communication ports has been described, three or more communication ports may be provided. When the number of communication ports is S and the power supply devices 1 are connected in series up to N layers, the number of connectable power supply devices 1 is represented by the following formula.

For example, when S=3 and N=2, the number of power supply devices 1 connected is nine. When S=3 and N=3, the number of power supply devices 1 connected is 21.

Further, the configuration in which nothing is connected to the second communication unit 19e of the terminal power supply device 1 has been described, but the second communication unit 19e of the two terminal power supply devices 1 may be connected by the communication unit 19c. In this case, the plurality of power supply devices 1 are connected in a ring shape. Even if a part of the communication line 3 is disconnected, the first power supply device 1 can continue the output control of the plurality of second power supply devices 1.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is not defined by the above meaning but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

1 Power Supply Device 2 Load 3 Communication Line 1a Positive Output Terminal 1b Negative Output Terminal 1c Control Terminal 10 Operation Panel 11 Input Section 12 Rectifier 13 Inverter 14 Transformer 15 Rectifier/Smoother 16 Voltage Detection Section 17 Current Detection Section 18 Main Control Section 19 Signal Processing Part 19a Control information calculating part 19b PWM control part 19c Communication part 19d First communication part 19e Second communication part 20 Welding torch 21 Welding wire 22 Base metal

Claims (5)

A plurality of power supply devices connected in parallel to a common load are connected in series via a communication line, and the first power supply device transmits control information for controlling voltage or current output to the load. A power supply system for controlling voltage or current output to the load by transmitting to a plurality of second power supply devices via the communication line,
The plurality of power supply devices,
A current detection unit that detects a current output from the device to the load,
A communication unit that transmits and receives current information related to the current output to the load,
The communication unit of the second power supply device at the terminal transmits current information indicating the current output from the device to the load to the second power supply device at the non-terminal, and the second power supply at the non-terminal The communication unit of the device receives the current information transmitted from the other second power supply device on the terminal side, and calculates the sum of the current indicated by the received current information and the current output from the device to the load. And transmitting the current information to the first power supply device or the second power supply device on the first power supply device side,
The first power supply device is
A voltage detection unit that detects the voltage output from the device to the load,
The voltage or current output to the load based on the information of the voltage detected by the voltage detection unit, the current information received by the communication unit, and the information of the current detected by the current detection unit. and a calculation unit for calculating a control information for controlling,
The current information related to the sum total transmitted from the second power supply device is
The number of the plurality of second power supply devices and the self device on the terminal side, and the average value of the currents output from the plurality of second power supply devices and the self device
Including power supply system. The communication unit is
The power supply system according to claim 1 , comprising a first communication unit and a second communication unit for connecting the plurality of power supply devices in series. The first communication unit and the second communication unit of the first power supply device,
The power supply system according to claim 2 , wherein each of the plurality of second power supply devices is connected in series. A power supply device that receives control information for controlling voltage or current output to a load, and outputs voltage and current to the load based on the received control information,
A first communication unit and a second communication unit that are connected to a plurality of other power supply devices and that transmit and receive information to and from the power supply devices;
A current detection unit that detects a current output to the load,
The second communication unit receives current information indicating a current output to the load from the other power supply device connected to the second communication unit, and the first communication unit indicates the received current information. The current information related to the sum of the current and the current output from the device to the load is transmitted to the other power supply device connected to the first communication unit ,
The current information related to the sum is
The number of the other power supply devices and the own device connected to the second communication unit, and the average value of the currents output from the other power supply devices and the own device
Power supply including . A power supply device that transmits control information for controlling a voltage or current output to a load to a plurality of other power supply devices, and controls the voltage or current output from each power supply device to the load,
A current detection unit that detects a current output from the device to the load,
A voltage detection unit that detects the voltage output from the device to the load,
A communication unit that receives current information related to the sum of currents output to the load from the other plurality of power supply devices,
Voltage or current output to the load based on information on the voltage detected by the voltage detection unit, current information received by the communication unit, and information on the current detected by the current detection unit and a calculation unit for calculating a control information for controlling,
The current information related to the sum is
The number of the other plurality of power supply devices and the average value of the currents output from the other plurality of power supply devices
Power supply including .

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