JP2011055636A - Dc power supply apparatus and method for controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC power supply apparatus reducing power loss by controlling the number of rectifier units to operate the rectifier units at high power conversion efficiency when the DC power supply apparatus having a plurality of rectifier units for converting AC power into DC power operates with inefficient load rate. <P>SOLUTION: This DC power supply apparatus includes: a plurality of rectifier units connected in parallel between output terminals for inputting AC power and outputting DC power; a current sensor for measuring the current value of the DC power; and an available unit number controller for controlling the number of available rectifier units at which the loss generated in a power conversion process from AC to DC in each rectifier unit becomes minimum at the current value. Each rectifier unit compares a detected voltage value detected by dividing its own voltage by a voltage dividing circuit with a reference voltage, controls the detected voltage to be equal to the reference voltage, and outputs the voltage via a diode and a semiconductor switch which are connected in parallel. The available unit number controller controls the voltage dividing ratio and the operation of the number of available rectifier units. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a DC power supply device used in a communication building, a data center, and the like and a control method thereof.

A DC power supply device is usually configured by connecting a plurality of rectifier units in parallel to a load (see, for example, Patent Document 1 and Patent Document 2).
Since each rectifier unit is connected in parallel with the load, each of the load currents connected to the load in parallel is uniformly supplied. For example, when supplying 100 A to the load, if five rectifier units are provided in parallel, each rectifier unit supplies power by 20 A.

JP 2006-311736 A JP 2007-318949 A

  However, when actually operating the DC power supply device, it is always necessary to operate all the rectifier units in the DC power supply device assuming that the load current becomes maximum, and the rectifier unit is low. There are cases where it is necessary to operate at a load factor (output current / rated current). However, generally, when the rectifier unit is operated at a low load factor, the power conversion efficiency is low, and extra power loss may occur in the power conversion in the rectifier unit.

  The present invention has been made in view of such circumstances, and in the case where a DC power supply device equipped with a plurality of rectifier units that convert AC power into DC power is operating at an inefficient load factor, the load current is It is an object of the present invention to provide a DC power supply device and a control method thereof that can control the number of rectifier units that output power to operate the rectifier units with high power conversion efficiency and reduce power loss.

  The direct current power supply device of the present invention has a plurality of rectifier units (for example, the rectifier units 2-1 and 2-2 in the embodiment, connected in parallel with an output terminal that inputs alternating current power and outputs direct current power). 2-3, ..., 2-n), a current sensor that measures the current value of the DC power, and outputs the current value of the DC power (for example, the current sensor 3 in the embodiment), and the current value, Operation number control for determining the number of operating rectifier units that minimizes the loss generated in the process of power conversion from alternating current to direct current of each of the rectifier units, and controlling so that DC power is output from the rectifier units of the operating number Unit (for example, the operating number control unit 5 in the embodiment), and the rectifier unit distributes its output voltage by a voltage dividing circuit (for example, the voltage dividing circuit 2-1d in the embodiment). The divided detection voltage value is compared with a preset reference voltage, and control is performed so that the detection voltage becomes equal to the reference voltage, and a diode (for example, the diode 2-1g1 in the embodiment) and a semiconductor switch (For example, a semiconductor switch 2-1g2 in the embodiment) A voltage is output via a parallel connection, and the operation number control unit controls the voltage dividing ratio of the voltage dividing circuit, so that the rectification unit corresponding to the operation number It is characterized by performing operation control.

  In the DC power supply device of the present invention, the operating number control unit controls the voltage dividing ratio of the voltage dividing circuit, raises the detected voltage value compared to before voltage division, and sets the voltage value of the output voltage before the control. The power supply of the rectifier unit is stopped by lowering the voltage compared to the voltage.

  In the DC power supply device according to the present invention, the operating number control unit sets the semiconductor switch provided in the rectifier unit to be supplied with power to a conductive state and disables the semiconductor switch provided in the rectifier unit to stop the power supply. It is characterized by reducing the power loss which generate | occur | produces in the said diode part by performing control which makes it a conduction | electrical_connection state.

  In the DC power supply device of the present invention, the voltage dividing circuit is configured by connecting resistors in series, and a switch (for example, the switch 2-1e in the embodiment) is connected in parallel with any of the resistors. The operating number control section controls the voltage dividing ratio of the voltage dividing circuit by controlling the opening and closing of the switch.

  In the DC power supply device of the present invention, the voltage dividing ratio of the detected voltage value is set in advance so that any of the voltages controlled by the operating number control unit is within a voltage range (load input voltage range) in which the load can operate. It is characterized by.

  In the DC power supply device of the present invention, the operating number control unit sets the current value of the DC power and the operating number of rectifier units that minimize the conversion loss at the current value. A table (for example, the number of operating units shown in FIG. 3 in the embodiment) and the number of operating rectifier units corresponding to the current value from the current sensor are read from the operating number table to obtain the number of operating rectifier units. It has a calculation part and a control part which controls the switch according to the number of operation which the calculation part asked.

  The DC power supply device according to the present invention includes a loss table in which the operating number control unit associates a current value output per rectifier unit with a power loss in the case of the current value, and a current from the current sensor. The current value is divided by the number of currently operating rectifier units to obtain a first current value of the output current per unit, and the power loss corresponding to the first current value is represented in the loss table. The current value from the current sensor is divided by the number obtained by increasing or decreasing the current operating number by one to obtain the second and third current values, respectively, and the second and third current values are obtained. When the power loss corresponding to each is read from the loss table and the power loss at the first current value is smaller than the power loss at the second and third current values, the current operating number is calculated. If the power loss in the reduced number is small, subtract to the number with the smallest power loss, while if the power loss in the increased number is small, increase to the number with the smallest power loss. A calculation unit that outputs the number of small power losses obtained as the number of operating rectifier units, and a control unit that controls the switch in correspondence with the number of operating units determined by the calculation unit. Features.

In the DC power supply device of the present invention, the semiconductor switch is any one of a MOS-FET, a junction transistor, a static induction transistor, or an insulated gate bipolar transistor, and the diode is a parasitic diode of the transistor. And
In the DC power supply device of the present invention, the semiconductor switch is one of a MOS-FET, a junction transistor, an electrostatic induction transistor, or an insulated gate bipolar transistor, and the diode indicates the output direction of the DC power with the transistor. It is a forward direction and is connected in parallel.
The method for controlling a DC power supply device according to the present invention includes a process in which each of a plurality of rectifier units connected in parallel converts AC power into DC power, and outputs the DC power to the same output terminal. The process of measuring the current value of the DC power and outputting the current value of the DC power, and the loss that the operating unit control unit generates in the process of power conversion from AC to DC of each of the rectifier units by the current value The number of operating rectifier units that minimizes the number of rectifier units, the process of controlling DC power to be output from the rectifier units of the operating number, and the detected voltage obtained by dividing the output voltage of the rectifier units by a voltage dividing circuit The value is compared with a preset reference voltage, control is performed so that the detected voltage is equal to the reference voltage, and the voltage is connected via a parallel connection of a diode and a semiconductor switch. The steps of outputting, the operation number controller, by controlling the voltage dividing ratio of the voltage dividing circuit, and having a process of performing the operation control of the rectifier unit corresponding to said operating quantity.

As described above, according to the present invention, even when the load power changes and the load current supplied to the load (the output current output from the DC power supply) fluctuates, Determine the number of rectifier units in operation that reduce power loss.
Further, according to the present invention, in order to set the number of operating rectifier units to be in the operating state as described above, the output voltage of the rectifier unit that stops the supply of the load current is reduced, and the load current is forwarded from the diode. Since the load current is supplied from the rectifier unit of an appropriate number of operating units so that it does not flow, it is possible to supply load power more efficiently, and it is possible to suppress excessive energy consumption compared to the conventional case. .

  Further, according to the present invention, the output voltage of the rectifier unit to be stopped is made lower than the output voltage of the rectifier unit not to be stopped, that is, the output voltage of the rectifier unit to be stopped is made lower than the voltage value of the output terminal on the cathode side of the diode. Since the output of the load current of the rectifier unit is stopped by turning off the diode, the voltage value of the output terminal is equal to the forward voltage drop of the diode with respect to the output voltage even if the load current increases rapidly. By lowering the voltage, the diode is turned on, and the rectifier unit that has stopped outputting supplies the load current, so that the voltage level required by the load can be maintained.

It is a block diagram which shows the structural example of the DC power supply device by the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the operation number control part 5 of FIG. In 1st Embodiment, the calculating part 12 is a conceptual diagram which shows the structure of the operation number table used for the calculation process of the operation number of a rectifier unit. It is a graph which shows a response | compatibility with the output [%] and output voltage of each rectifier unit. It is a wave form diagram explaining the process of the control part 15 when the output voltage of a DC power supply device increases rapidly. In 2nd Embodiment, it is a conceptual diagram which shows the structure of the loss table which the calculating part 12 memorize | stored in the memory | storage part 14 uses for calculation of the number of operation. It is a flowchart which shows the operation example of the calculation process of the calculating part 12 in 2nd Embodiment of the operation number of a rectifier unit. It is another flowchart in which the calculating part 12 in 2nd Embodiment shows the operation example of the calculation process of the operation number of a rectifier unit. It is a flowchart in which the calculating part 12 in 2nd Embodiment shows the other operation example of the calculation process of the operation number of a rectifier unit. It is a flowchart in which the calculating part 12 in 2nd Embodiment shows the other operation example of the calculation process of the operation number of a rectifier unit.

<First Embodiment>
Hereinafter, the DC power supply device according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of a DC power supply device according to the first embodiment of the present invention.
As shown in this figure, the DC power supply device 1 according to the present embodiment receives AC power from a commercial power source (AC power supply) 100, and DC power is supplied to the PFC unit 2-1b via the FIL unit 2-1a. The DC power stabilized by the DC-DC unit 2-1c controlled by the negative feedback circuit and supplied to the load facility 200 is supplied to the load facility 200.
The DC power supply device 1 includes a rectifier unit 2-1, a rectifier unit 2-2, a rectifier unit 2-3,..., A rectifier unit 2-n, a current sensor 3, a current measuring unit 4, and an operating number control unit 5. Have.

Each of the rectifier unit 2-1 to the rectifier unit 2-n is provided in parallel between the commercial power source 100 and the load facility 200, each input is connected to the commercial power source 100, and each output terminal C Are connected at connection point A.
The current sensor 3 is provided between the connection point A and the load facility 200. The current measuring unit 4 is connected to the current sensor 3 and the operating number control unit 5. The operating number control unit 5 is connected to each of the rectifier unit 2-1 to the rectifier unit 2-n.

Next, the function of each part will be described.
The current sensor 3 measures the current value of the load current output from the output terminal 9 and outputs the measured current value to the current measuring unit 4.
The current measuring unit 4 reads an input current value at a predetermined measurement cycle (a cycle shorter than a control cycle described later), and outputs the read current value data to the operating number control unit 5 as current value data.
Based on the current value data input from the current measuring unit 4, the operating unit control unit 5 operates the rectifier that minimizes the power loss when converting the direct current from the alternating current of each of the rectifier units 2-1 to 2-n. The number of units is obtained, and the operating state and standby state of each rectifier unit are controlled so that DC power is output from the rectifier units of the obtained number of operating units. Here, the operating state is a state where the rectifier unit is operating and outputting DC power to the load, while the stopped state is a state where the rectifier unit is operating but the DC power to the load is being output. Indicates that no power is being output. The operation of the supply state and the standby state will be described in the description of the rectifier unit.

Next, the configuration of the rectifier unit 2-1 to rectifier unit 2-n in FIG. 1 will be described.
Each of the rectifier unit 2-1 to rectifier unit 2-n has the same configuration. Hereinafter, the configuration of the rectifier unit will be described with reference to the rectifier unit 2-1, but the other rectifier units 2-2 to 2- n also has the same configuration as that of the rectifier unit 2-1 described below.
The rectifier unit 2-1 includes an FIL unit 2-1a, a PFC unit (rectifier circuit having a power factor improving function) 2-1b, a DC-DC unit 2-1c, a voltage dividing circuit 2-1d, and a conversion control unit 2- 1f and a parallel circuit 2-1g.
In the voltage dividing circuit 2-1d, for example, resistors R1 (resistance value r1), R2 (resistance value r2), and R3 (resistance value r3) are output via the output of the DC-DC unit 2-1c (diode 2-1g). Switch 2 is connected in series between the positive side terminal of the rectifier unit and the negative side terminal of the rectifier unit. At the connection point P of the resistors R2 and R3 and the negative side terminal of the rectifier unit, the switch 2 -1e is connected in parallel with the resistor R3.
The conversion control unit 2-1f includes an amplifier circuit 2-1f1, a comparator 2-1f2, a drive circuit 2-1f3, a reference voltage source 2-1f4, and a triangular wave generation circuit 2-1f5.
The parallel circuit 2-1g is configured by a parallel connection of a diode 2-1g1 and a semiconductor switch 2-1g2.
As the semiconductor switch 2-1g2, a MOS (Metal Oxide Semiconductor) -FET (Field Effect Transistor), a junction transistor (BJT), a static induction transistor (SIT), an insulated gate bipolar transistor (IGBT: Insulated Gate Bipolar Transistor) may be used. The diode 2-1g1 can be a diode element or a parasitic diode of each transistor. For example, in FIG. 1, an n-channel MOS-FET is used as the semiconductor switch 2-1g2.
The FIL unit 2-1a has an input side connected to the commercial grid power 100 and an output side connected to an input of the PFC unit 2-1b. The output side of the PFC unit 2-1b is connected to the DC-DC unit 2-1c. In the DC-DC unit 2-1c, the output terminal C is connected to the output terminal C of the rectifier unit 2-1 via the parallel circuit 2-1g. The diode 2-1g1 of the parallel circuit 2-1g has an anode connected to the output terminal B of the DC-DC unit 2-1c and a cathode connected to the output terminal A of the rectifier unit 2-1. The semiconductor switch 2-1g2 of the parallel circuit 2-1g has a drain connected to the output terminal B, a source connected to the output terminal C, and a gate connected to the operating number control unit 5.
In the DC-DC unit 2-1c, a voltage dividing circuit 2-1d and a conversion control unit 2-1f are connected in series between the output terminal B and the control terminal D.

Next, the function of each part of the rectifier unit 2-1 will be described.
The FIL unit 2-1a is composed of a low-pass filter, and removes noise superimposed on the waveform of the alternating current input from the commercial power source 100. The PFC unit 2-1b is a rectifier circuit having a power factor improvement function by high-frequency switching.
The DC-DC unit 2-1c is input according to the duty ratio of the drive pulse output from the conversion control unit 2-1f (ratio of the “H” level period and the “L” level period in one cycle of the pulse). DC voltage corresponding to the duty ratio is converted to a DC voltage having a stable voltage value.
The voltage dividing circuit 2-1d outputs a divided voltage that is a voltage at a connection point Q between the resistors R1 and R2. Here, when the switch 2-1e is opened (non-conducting state), the divided voltage value at the connection point Q is Vins = Vh where the voltage output from the DC-DC unit 2-1c is Vh. (R2 + r3) / (r1 + r2 + r3) On the other hand, when the switch 2-1e is closed (conductive state), the resistor R3 is canceled, so the divided voltage value at the connection point Q is Vdis = Vh (R2) / (r1 + r2) Here, the switch 2-1e is used, but a relay, contactor, semiconductor switch (for example, transistor), or a circuit breaker that can be opened and closed by an external signal may be used.
Here, by setting the resistance values of the resistors R1 to R3 so that Vdis> Vins at the same Vh, the conversion control unit 2-1f closes the switch 2-1e (conduction state). ) To open (non-conducting state), the voltage value of the output voltage of the rectifier unit 2-1 is controlled to be lower than the voltage value of the output voltage of the rectifier unit in the operating state as compared with the closed state. It will be. As a result, the rectifier unit 2-1 can be turned off by the diode 2-1g1 to enter a standby state in which output of current is stopped.

The amplifier circuit 2-1f1 controls the divided voltage value input from the voltage dividing circuit 2-1d and the reference voltage value output from the internal reference voltage source 2-1f4 (the output voltage is controlled to a preset voltage value). Voltage), and the difference is amplified and output to the next-stage comparator 2-1f2.
In the amplifier circuit 2-1f1, the reference voltage value is applied to the non-inverting input terminal (+), the resistor R4 is connected between the inverting input terminal (−) and the output terminal, and the resistance is connected to the inverting input terminal (−). The divided voltage value is input via R5.

The comparator 2-1f2 compares the voltage value obtained by amplifying the difference between the reference voltage value and the divided voltage value by the amplifier circuit 2-1f1 with the voltage value of the triangular wave output from the triangular wave generation circuit 2-1f5. The drive circuit 2-1f3 is a pulse in which the time width of the voltage value of the triangular wave exceeding the amplified voltage value is “H” level and the time width of the voltage value of the triangular wave less than the amplified voltage value is “L” level. Output for.
The drive circuit 2-1f3 outputs the input pulse as a drive pulse to the DC-DC unit 2-1c.
The DC-DC unit 2-1c increases the voltage value of the output voltage as the period of the “H” level becomes longer in the duty ratio (duty ratio) of the input drive pulse.

That is, if the divided voltage value output from the voltage dividing circuit 2-1d is higher than the reference voltage, the conversion control unit 2-1f determines that the voltage value of the preset output voltage is output, and the DC-DC The period of the “H” level of the drive pulse for the part 2-1c is shortened.
For this reason, when the detection voltage value rises by opening the switch 2-1e from the closed state, the conversion control unit 2-1f is less than the preset output voltage value during operation, and the diode 2-1g A drive pulse is output to the DC-DC unit 2-1c so that the DC-DC unit 2-1c outputs a voltage value (standby voltage value) that turns off.

With the configuration described above, in the rectifier unit 2-1 in the standby state, the semiconductor switch 2-1 g 2 is in the off state (non-conduction state), and the output of the DC-DC unit 2-1 c is in parallel with this semiconductor switch 2-1 g 2. Since it is electrically connected to the connection point A only through the connected diode 2-1g1, when the switch 2-1e is opened from the closed state, the output voltage is the standby voltage value. Since the diode 2-1g is turned off lower than the operating voltage value output by the other rectifying unit that is operating, no current flows from the anode to the cathode of the diode 2-1g1, and the DC power output It will be in the standby state which stopped.
On the other hand, in the operating rectifier unit 2-1, the semiconductor switch 2-1g2 is in an on state (conducting state), and the output of the DC-DC unit 2-1c is connected to the connection point A via the semiconductor switch 2-1g2. And the switch 2-1e is closed, the output voltage is a movable voltage value, and a DC power output is supplied to the connection point A.

Therefore, the operation number control unit 5 operates each switch unit by controlling the switch 2-1e in each rectifier unit to open / close and controlling the semiconductor switch 2-1g2 to be turned on / off so that the calculated operation number is obtained. State (state in which the rectifier unit is operating and outputting DC power to the load) or standby state (state in which the rectifier unit is operating but not outputting DC power to the load).
That is, the operating number control unit 5 controls the voltage dividing ratio of each voltage dividing circuit of the rectifier units 2-1 to 2-n, increases the detected voltage value compared to before voltage dividing, and sets the voltage value of the output voltage. The DC power output from the rectifier unit is stopped by lowering the output voltage compared with the operating output voltage, and the standby state is set.
Here, the operating number control unit 5 opens (non-conducting) the switch 2-1e in the rectifier unit that is in the standby state, and turns off the semiconductor switch 2-1g2. On the other hand, the operating number control unit 5 closes the switch 2-1e in the movable rectifier unit (turns on) and turns on the semiconductor switch 2-1g2.

In the present embodiment, the B contact type switch 2-1e is used in the voltage dividing circuit 2-1d. However, the A contact type switch of the voltage dividing circuit 2-1d described in the frame Z is used. It is good also as a structure using 2-1e.
That is, in the voltage dividing circuit 2-1d in the frame Z, the detected voltage value input to the inverting input terminal (−) of the amplifier circuit 2-1f1 is output from the connection point Q between the resistors R2 and R3. Is done. The switch 2-1e is connected between a connection point P between the resistors R1 and R2 and a connection point Q between the resistors R2 and R3.
Therefore, when the voltage dividing circuit 2-1d of the frame Z is used, contrary to the switching control of the switch described above, when the rectifier unit is put into operation, the switch 21e is opened and the output voltage of the rectifier unit is opened. The output voltage is output from the rectifier unit. On the other hand, when the rectifier unit is set to the standby state, the switch 2-1e is closed, the detected voltage value is increased compared to the operating state, the output voltage of the rectifier unit is decreased to the standby voltage value, and the cathode side Control so that the voltage value on the anode side becomes lower (the output voltage of the operating voltage value is output by the other rectifier unit to the connection point A to which the cathode is connected), and the diode 2-1g is turned off. Then, the DC power output of the rectification unit is stopped.
With the above-described configuration, a switch or the like is inserted between the rectifier unit and the load, and the DC power output can be easily supplied from each rectifier unit to the load without turning off the switch and turning it off. It is possible to enter a standby state that is not performed.

Next, the operation number control unit 5 in FIG. 1 will be described with reference to FIG. FIG. 2 is a conceptual diagram showing the configuration of the operating number control unit 5 in FIG.
The operating number control unit 5 includes an input unit 11, a calculation unit 12, a timer 13, a storage unit 14, and a control unit 15.
The control unit 15 reads, via the input unit 11, the operating number table in which the current value of the load current and the operating number that minimizes the power loss at the current value are indicated, and the storage unit 14. Are stored in advance before the operation of the DC power supply, that is, before the time when the DC power supply is first activated.
Further, the control unit 15 reads the current value of the load power input from the current measurement unit 4 for each preset measurement cycle, and stores the read time and the current value read at this time in association with each other. Write to part 14. In addition, when calculating the number of operating units in the control cycle notified by the cycle notification signal indicating that the control cycle has been reached, the control unit 15 detects the latest time stored, and this detected latest The current value of the load power corresponding to the time is read from the storage unit 14 and the read current value is output to the calculation unit 12.

The timer 13 is a timer that counts the control cycle in which the operating number control unit 5 controls the operating number of rectifiers. The timer 13 counts the time and compares the counted value with a preset value set as a control cycle. In addition, when the count value exceeds the set value, it is detected that the control cycle has been reached, and a cycle notification signal indicating the control cycle is output to the control unit 15, and the count value is reset, Perform a new count operation.
The calculation unit 12 reads the number of operating units corresponding to the current value of the load current input from the control unit 15 in the control cycle from the operating unit table of the storage unit 14.

  The operating unit table shows a correspondence between the current value of the load current and the number of standby rectifier units (standby units) in order to obtain the operating unit with the smallest power loss at the load current. It is the table provided in. FIG. 3 is a conceptual diagram showing a configuration example of this operating number table. 3 is a table in which the load current supplied to the load corresponds to the standby number which is the number of the standby state in order to obtain the most efficient operating number with the least power loss in the load current. Is stored in the storage unit 14. In addition, the number of operating tables in FIG. 3 shows that n = 8 rectifier units included in the DC power supply device. In this figure, the number of standby units is shown, but it may be formed so as to show the number of operating units with the lowest power loss in load current and the efficiency.

A method for creating this table will be described below.
Each of the rectifier units 2-1 to 2-n samples the voltage at the point B at the point B in FIG. 1, feeds back the sampled voltage, and is constant and the same voltage so that the voltage becomes a set voltage. Constant voltage control (CV) with the target of
Further, each of the rectifier units 2-1 to 2-n is connected in parallel between the commercial grid power 100 and the point A, that is, all the outputs are commonly connected to the point A. For this reason, each rectifier unit uniformly outputs a current value obtained by dividing the load current output from the DC power supply device by the number of operating units.
The load current IL output from the DC power supply is divided by the number of the minimum number of operating units or more that can be supplied in total, and the output current of each rectifier unit for each different number of operating units is calculated.

For example, in the case of the maximum load current IL that can be supplied by one rectifier unit, the output current output from each rectifier unit is obtained as I _{un ′} by the following equation.
Iun _' = IL / n', Iun _' = IL / (n'-1), ..., Iun _' = IL
Here, the output current _{Iun ′} indicates the output current of each rectifier unit when the rectifier unit n _′ is operated.

Then, the power loss P corresponding to each calculated output current is obtained from the “load current-loss power” characteristic table of the rectifier unit (for example, a table showing the loss corresponding to the load current shown in FIG. 6 described later). The power loss corresponding to the calculated output current (load current) is read out. Then, the total power loss for each number is calculated by multiplying the number of rectifier units when divided. That is, when the output current is I _{un ′} , the obtained power loss P _un ′ is multiplied by n ′ to calculate the total power loss in the DC power supply device. Then, the number of rectifier units with the smallest total power loss is set as the number of operating load currents IL, and this number of operating units is subtracted from the total number of rectifier units to obtain the number of standby units. This processing is performed for each predetermined load current range from the load current IL that can be output by one rectifier unit to the maximum load current ILunit that can be output by the number of all rectifier units provided in the DC power supply unit. Then, an operating number table having the table configuration shown in FIG. 3 is created that shows the number of standby rectifier units that are set to the standby state at the time of the load current IL.

  In the above-described processing, the configuration of the table of FIG. 3 showing the load current value and the number of standby units corresponding to the load current value is shown, but the load current value and the load current value correspond to the load current value. An operating number table may be created in which the number of operating units is stored correspondingly. Here, the operating number table shows the load current and the optimum operating number that minimizes the total power loss in the load current.

Next, an operation example of the DC power supply device according to the first embodiment will be described with reference to FIGS. 1 to 3.
The storage unit 14 will be described in a state where the operating number table (table indicating the number of standby units at each load current value) shown in FIG. 3 has already been read.
a. The current measuring unit 4 reads the current value of the load current output from the current sensor 3 at every preset measurement cycle, and outputs it to the operating number control unit 5.
The control unit 15 writes the current value of the input load current in the storage unit 14 corresponding to the input time.
b. When a cycle notification signal indicating a control cycle is input from the timer 13, the control unit 15 corresponds to the time closest to the current time and the current value of the load current stored in the storage unit 14, that is, the latest current. The value is read and output to the calculation unit 12.
d. The calculation unit 12 reads out the standby number corresponding to the current value of the input load current from the operating number table of the storage unit 14 and outputs it to the control unit 15.
e. Since the control unit 15 has the same number of standby units input from the calculation unit 12 in the current DC power supply device, the switch 2-1e of the voltage dividing circuit 2-1d in each rectifier unit is opened (non-conductive state). Close (conduction state) control and on / off control of the semiconductor switch 2-1g2 are performed.
B. ~ E. This process is performed for each cycle and each control cycle. a. Is repeatedly performed in a preset measurement cycle shorter than the control cycle.

In the above e, for example, when the DC power supply device has eight rectifier units 2-1 to 2-8, and the number of standby units currently in the standby state is three (2-1 to 2-3), When the number of units is four and input from the calculation unit 12, the control unit 15 opens the switch 2-1e in the voltage dividing circuit of the rectifier unit 2-4 in order of numbers (decreases the output voltage of the rectifier unit). Then, the semiconductor switch 2-1g2 is turned off, and the four rectifier units 2-1 to 2-4 are placed in a standby state where no load current is supplied by turning off the diodes.
On the other hand, if the DC power supply device has eight rectifier units 2-1 to 2-8 and the number of units currently in standby, that is, the number of standby units is three (2-1 to 2-3), Are input from the arithmetic unit 12 as two units, the control unit 15 turns on the semiconductor switch 1-1g2 of the rectifier unit 2-3 in the reverse order of the case of stopping, and the switch 2-in the voltage divider circuit. 1e is closed, the rectifier unit 2-3 is set in an operating state, and the two rectifier units 2-1 and 2-2 are controlled in a standby state in which no load current is supplied by turning off the diode.

As described above, according to the present embodiment, the load current supplied to the load facility 200 operates in the state where the total loss of the current units provided in the DC power supply device is the smallest, that is, the state where the power conversion efficiency is the highest. It is possible to suppress wasteful consumption of electrical energy.
Further, in the present embodiment, as shown in the table of FIG. 3, when the current value of the load current is 0, it is included when the total loss of the rectifier unit is the smallest when the number of operating units is one. The switch 2-1e of each of the rectifier units is opened, the switch 2-1e of one rectifier unit is closed, and at least one rectifier unit is in an operating state.

Further, as shown in FIG. 4, each rectifier unit has a characteristic that the output voltage decreases as the load capacity of the connected load equipment 200 increases (impedance decreases). Here, FIG. 4 is a graph showing the correspondence between the output [%] of each rectifier unit and the output voltage, where the horizontal axis is the output and the vertical axis is the output voltage.
For example, if two units of rectifier units 2-1 and 2-2 are provided in the DC power supply device and each rectifier unit is operating at 40% output, it operates at 80% output with one rectifier unit. Since the conversion efficiency is better, it shows a state in which one of the rectifier units 2-1 is operated. Here, the load factor [%] is a ratio of the load current value output from the rectifier unit to the unit maximum output current value of the rectifier.

Line L1 indicates the output characteristic of the rectifier unit 2-1 that outputs the load current, and line L2 indicates the output characteristic of the rectifier unit 2-2 in the standby state in which the output of the load current is stopped.
At this time, if the load capacity is suddenly reduced and the load current is increased during the control cycle for performing the operation number control, the load current is insufficient in the current operating number (one of the rectifier units 2-1). The voltage value of the output voltage at the output terminal of the DC power supply device is reduced from the constant voltage value Vn (operating voltage value).
Here, the standby voltage value of the output voltage output from the rectifier unit in the standby state is set as a voltage value V1 which is a lower limit value as an input allowable range in which the load facility 200 can normally operate.

As a result, for example, when the load facility 200 is added or the load power increases rapidly due to a change in the operation state of the load facility 200 and the load current increases, the voltage of the output voltage of the rectifier unit in the operating state Even when the operating voltage value, which is a value, drops from the constant voltage value Vn, when the voltage of the rectifier unit in the standby state is turned on and the current starts to flow when the voltage value decreases to the voltage value V1, the current state starts. The rectifier unit starts operating, and all the rectifier units in the DC power supply device are in a state of sharing and supplying the load current with the output voltage as the voltage value V1.
As a result, even if the load power changes abruptly, the voltage value V1 of the operating range voltage is supplied from the DC power source to the load equipment 200, so that the load equipment 200 changes so that the load current increases rapidly. Even if it exists, it does not stop, and as shown in FIG. 5, a stable operation state can be maintained until the number of operating units is controlled in the next control cycle. FIG. 5 is a waveform diagram for explaining the processing of the control unit 15 when the output voltage of the DC power supply device suddenly increases. The horizontal axis represents time, and the vertical axis represents the voltage value of the output voltage.

In order to perform the above-described operation, the output voltage of the rectifier unit is set to the voltage value V1, that is, Vins = V1 · (r2 + r3) / (r1 + r2 + r3) and Vcon = Vn · (r2) / (r1 + r2) Therefore, it is necessary to set the resistance value r1 of the resistor R1, the resistance value r2 of the resistor R2, and the resistance value r3 of the resistor R3.
Thereby, the detected voltage value is set so that the voltage value V1 is included in the voltage range in which the load facility 200 operates.

<Second Embodiment>
Hereinafter, the DC power supply device according to the second embodiment of the present invention will be described with reference to the drawings. The configuration of the second embodiment is the same as that of the first embodiment shown in FIG. 1 except that the number of operating units calculated by the calculation unit 12 and the calculation unit 12 stored in the storage unit 14 are different. Only the table used for calculating the number of operating units is different.
Hereinafter, the points of the second embodiment different from the first embodiment will be described.
As shown in FIG. 6, the table stored in the storage unit 14 includes the output current I _{LS of} one rectifier unit (output current of 0% to 100% with respect to the rated current) I _LS and the output current I _LS . It is a loss table with which power loss P _{loss at the} time of output is matched.
The control unit 15 also inputs the loss table from the outside via the input unit 11, and writes and stores the loss table in the storage unit 14 in advance before the DC power supply device is activated for the first time. FIG. 6 is a conceptual diagram illustrating a configuration of a loss table stored in the storage unit 14 and used by the calculation unit 12 to calculate the number of operating units in the second embodiment.
The control unit 15 detects the number of operating rectifier units from the number of closed switches 2-1e, outputs the current number of operating rectifier units n _t to the computing unit 12, and simultaneously outputs the current. The current value of the load power input from the measurement unit 4 is output to the calculation unit 12 as the total current _ILt of the current value data.

Operation Example of Operation Number Calculation Processing in Calculation Unit 12 Hereinafter, with reference to the flowcharts of FIGS. 7 and 8, an operation example of operation number calculation processing using the total current _ILt of the current value data performed by the calculation unit 12 will be described. It explains using. 7 and 8 are flowcharts illustrating an operation example of the DC power supply device according to the second embodiment. In the following processing, the total number of rectifier units provided in the DC power supply device is n _all .
When the total current _ILt is input from the control unit 15, the calculation unit 12 inputs the current operating number _nt and the total current _ILt from the control unit 15 (step ST1), and the total current input I _Lt is divided by the number of operating units n _t and a predetermined digit number processing (for example, rounding off) is performed to calculate a unit load current I _Ltn per rectifier unit (step ST2).
And the calculating part 12 reads the electric power loss P _lossn memorize _| stored corresponding to the calculated unit load current _ILtn from the loss table of the memory _| storage part 14 (step ST3).

Next, the computing unit 12 determines whether or not the current operating number is 1, that is, whether or not n _t = 1 (step ST13). Here, the operation unit 12 proceeds the process to step ST15 when n _t = 1, and proceeds the process to step ST14 when n _t ≠ 1.
When the determination in step ST13 is n _t ≠ 1, the arithmetic unit 12 determines whether all the rectifier units are currently in operation, that is, whether n _t = n _all (step ST14). . Here, the arithmetic unit 12 advances the process to step ST18 when n _t = n _all , and advances the process to step ST4 when n _t ≠ n _all .
Next, the calculation unit 12 divides the total current I _Lt by the number n (= n _t +1) obtained by adding 1 to the current operating number n _t and performs a predetermined number of digits processing (for example, rounding off). And unit load current I _{Ltn + 1} per rectifier unit is calculated (step ST4).
And the calculating part 12 _{reads the} electric power loss P _{lossn + 1} memorize _| stored corresponding to the calculated unit load current _{ILtn + 1} from the loss table of the memory _| storage part 14 (step ST5).

Next, the operation unit 12 determines whether or not the read power loss P _{lossn + 1} is larger than the current power loss P _lossn (step ST8). If larger, the process proceeds to step ST6. Then, the process proceeds to step ST10.
When the power loss _{P lossn + 1} is greater than the power loss _{P Lossn,} computing unit 12, obtained by subtracting 1 from the current operating number _{n t,} the number n ₍₌ n t -1) by dividing the total current I _Lt Then, preset digit number processing (for example, rounding off) is performed to calculate a unit load current I _Ltn-1 per rectifier unit (step ST6).
And the calculating part 12 _{reads the} electric power loss P _lossn-1 memorize _| stored corresponding to the calculated unit load current _ILtn-1 from the loss table of the memory _| storage part 14 (step ST7).

Next, the calculation unit 12 determines whether or not the power loss P _lossn-1 is larger than the power loss P _lossn (step ST9). If larger, the process proceeds to step ST12, and if smaller, the process is performed. Proceed to step ST11.
When the power loss P _lossn-1 is larger than the power loss P _lossn , the calculation unit 12 outputs the number of operating units corresponding to the smallest power loss P to the control unit 15 (step ST12).
When the power loss P _lossn-1 is smaller than the power loss P _lossn , the calculation unit 12 determines whether n _t -1 is 1 (step ST11), and n _t -1 is 1. In this case, since the number of operating units cannot be decreased from n = 1, the process proceeds to step ST12. On the other hand, when n _t −1 is not 1, after performing the process of changing the operating unit n _t to n _t −1. Then, the process proceeds to step ST6.
Further, in step ST8, when the power loss _{P lossn + 1} less than the power loss _{P Lossn,} arithmetic unit _12, a determination _n t +1 is whether n _all (step _{S10), n} t +1 is n _all If n _t +1, the number of operating units cannot be increased beyond n _all , so the process proceeds to step ST12. On the other hand, if n _t +1 is not n _all , processing is performed to change the operating unit n _t to n _t +1. Then, the process proceeds to step ST4.

In step ST14, when n _t = n _all , the calculation unit 12 subtracts 1 from the current operating number n _t and divides the total current I _Lt by the number n (= n _t −1), _Preset digit processing (for example, rounding off, etc.) is performed to calculate a unit load current I _Ltn-1 per rectifier unit (step ST18).
And the calculating part 12 _{reads the} electric power loss P _lossn-1 memorize _| stored corresponding to the calculated unit load current _ILtn-1 from the loss table of the memory _| storage part 14 (step ST19).
Next, the operation unit 12 determines whether or not the power loss P _lossn-1 is larger than the power loss P _lossn (step ST20). If larger, the process proceeds to step ST12, and if smaller, the process is performed. Proceed to step ST21.
When the power loss P _lossn-1 is smaller than the power loss P _lossn , the calculation unit 12 determines whether n _t -1 is 1 (step ST21), and n _t -1 is 1. In this case, since the number of operating units cannot be decreased from n = 1, the process proceeds to step ST12. On the other hand, when n _t −1 is not 1, after performing the process of changing the operating unit n _t to n _t −1. Then, the process proceeds to step ST18.

In step ST13, when the current operating number n _t is 1, the calculation unit 12 divides the total current I _Lt by the number n (= n _t +1) obtained by adding 1 to the current operating number n _t. Then, preset digit number processing (for example, rounding off) is performed to calculate a unit load current I _{Ltn + 1} per rectifier unit (step ST15).
And the calculating part 12 _{reads the} electric power loss P _{lossn + 1} memorize _| stored corresponding to the calculated unit load current _{ILtn + 1} from the loss table of the memory _| storage part 14 (step ST16).
Next, the operation unit 12 determines whether or not the read power loss P _{lossn + 1} is larger than the current power loss P _lossn (step ST17), and proceeds to step ST12 if larger, whereas if smaller, it is smaller. Then, the process proceeds to step ST22.
When the power loss P _{lossn + 1} is smaller than the power loss P _lossn , the calculation unit 12 determines whether n _t +1 is n _all (step ST22). If n _t +1 is n _all , Since the number of operating units cannot be increased beyond n _all , the process proceeds to step ST12. On the other hand, when n _t +1 is not n _all , the processing is performed after changing the operating unit n _t to n _t +1. To step ST15.

Through the above-described processing, in step ST <b> 12, the calculation unit 12 outputs a new operating number corresponding to the smallest power loss P to the control unit 15 corresponding to the operating state of the load.
For example, when the power loss P _lossn is the smallest, the calculation unit 12 _outputs the current operation number n _t as the operation number of the calculation result to the control unit 15, and when the power loss P _{lossn + 1} is the smallest, the current operation number n _t + m units (m is the number of times step ST4 or ST15 has been processed) is output to the control unit 15 as the operation number of operation results, and when the power loss P _lossn−1 is the smallest, the current operation number n _t −m The table (m is the number of times step ST6 or ST18 has been processed) is output to the control unit 15 as the number of operating results.
Thereby, similarly to the first embodiment, the control unit 15 controls the switching of the switch 2-1e in the rectifier unit and the on / off of the semiconductor switch 2-1g2 so that the operating number input from the calculation unit 12 is obtained. Take control. That is, the control unit 15 closes the switch 2-1e in the movable rectifier unit and turns on the semiconductor switch 2-1g2, while opening the switch 2-1e in the non-movable rectifier unit. At the same time, the semiconductor switch 2-1g2 is turned off. As a result, the direct-current power supply apparatus supplies the direct-current power to the load by setting the rectifier units to the operating state corresponding to the operating state of the load and operating the number of operating units with the least power loss.

-Another example of operation of calculating the number of units in operation unit 12
Next, another operation example of the operation number calculation process using the total current _ILt of the current value data performed by the arithmetic unit 12 will be described with reference to the flowcharts of FIGS. 9 and 10. FIG. 9 and FIG. 10 are flowcharts showing other operation examples of the DC power supply device in the second embodiment. In the following processing, it is assumed that the total number of rectifier units provided in the DC power supply device is n _all as in the description of the operations in the flowcharts of FIGS. As shown in FIGS. 9 and 10, the flowcharts of other operation examples are shown in the order of steps ST13 and ST14 in the flowcharts of FIGS. 7 and 8, and steps ST4, ST5, ST8 and steps ST6, ST7, The order in the flow of ST9 is changed.

When the total current _ILt is input from the control unit 15, the calculation unit 12 inputs the current operating number _nt and the total current _ILt from the control unit 15 (step ST1), and the total current input I _Lt is divided by the number of operating units n _t and a predetermined digit number processing (for example, rounding off) is performed to calculate a unit load current I _Ltn per rectifier unit (step ST2).
And the calculating part 12 reads the electric power loss P _lossn memorize _| stored corresponding to the calculated unit load current _ILtn from the loss table of the memory _| storage part 14 (step ST3).

Next, the arithmetic unit 12 determines whether all the rectifier units are currently in operation, that is, whether n _t = n _all (step ST14). Here, the arithmetic unit 12 proceeds to step ST18 when n _t = n _all , and proceeds to step ST13 when n _t ≠ n _all .
When n _t ≠ n _all , the calculation unit 12 determines whether or not the current operating number is 1, that is, whether n _t = 1 (step ST13). Here, the arithmetic unit 12 advances the process to step ST15 when n _t = 1, and advances the process to step ST6 when n _t ≠ 1.

Next, when n _t ≠ 1 in step ST13, the calculation unit 12 subtracts 1 from the current operating number n _t and divides the total current I _Lt by the number n (= n _t −1). The set digit number processing (for example, rounding off) is performed to calculate a unit load current I _Ltn-1 per rectifier unit (step ST6).
And the calculating part 12 _{reads the} electric power loss P _lossn-1 memorize _| stored corresponding to the calculated unit load current _ILtn-1 from the loss table of the memory _| storage part 14 (step ST7).
Next, the operation unit 12 determines whether or not the power loss P _lossn-1 is larger than the power loss P _lossn (step ST9). If larger, the process proceeds to step ST4, while if smaller, the process is performed. Proceed to step ST11.

At this time, when the power loss _{P lossn-1} smaller than the power loss _{P Lossn,} computing unit _{12, n} t -1 is a judgment of whether or not 1 (step _{ST11), n} t -1 1 In some cases, since the number of operating units cannot be decreased from n = 1, the process proceeds to step ST12. On the other hand, when n _t −1 is not 1, processing for changing the operating unit n _t to n _t −1 was performed. Thereafter, the process proceeds to step ST6.
Here, when the power loss P _{lossn + 1} is larger than the power loss P _lossn , the calculation unit 12 outputs the number of operating units corresponding to the smallest power loss P to the control unit 15 (step ST12).

Then, when the power loss _{P lossn-1} greater than or equal to the power loss _{P Lossn,} computing unit 12, by adding 1 to the current operating number _{n t,} the total current I by the number n ₍₌ n t +1) _Lt is divided, a predetermined number of digits processing (for example, rounding off) is performed, unit load current _{ILtn + 1} per rectifier unit is calculated, and the process proceeds to step ST5 (step ST4).
Next, the calculating part 12 _{reads the} electric power loss P _{lossn + 1} memorize _| stored corresponding to the calculated unit load current _{ILtn + 1} from the loss table of the memory _| storage part 14 (step ST5).

Then, the calculation unit 12 determines whether or not the read power loss P _{lossn + 1} is larger than the current power loss P _lossn (step ST8). If larger, the process proceeds to step ST12. The process proceeds to step ST10.
In this case, in step ST8, when the power loss _{P lossn + 1} is not greater than the power loss _{P Lossn,} arithmetic unit _12, a determination _n t +1 is whether n _all (step _{S10), and} the _n t +1 If it is n _all, since beyond n _all not increase the operation number, the process proceeds to step ST12, _whereas, if _n t +1 is not n _all, to change the operation number _{n t} in _n t +1 process Then, the process proceeds to step ST4.

In step ST13, when the current operating number n _t is 1, the calculation unit 12 divides the total current I _Lt by the number n (= n _t +1) obtained by adding 1 to the current operating number n _t. Then, preset digit number processing (for example, rounding off) is performed to calculate a unit load current I _{Ltn + 1} per rectifier unit (step ST15).
And the calculating part 12 _{reads the} electric power loss P _{lossn + 1} memorize _| stored corresponding to the calculated unit load current _{ILtn + 1} from the loss table of the memory _| storage part 14 (step ST16).
Next, the operation unit 12 determines whether or not the read power loss P _{lossn + 1} is larger than the current power loss P _lossn (step ST17), and proceeds to step ST12 if larger, whereas if smaller, it is smaller. Then, the process proceeds to step ST22.
Then, when the power loss _{P lossn + 1} is not greater than the power loss _{P Lossn,} computing unit _{12, n} t +1 is a judgment of whether or not n _all (step _ST22), when _n t +1 is n _all , Since the number of operating units cannot be increased beyond n _all , the process proceeds to step ST12. On the other hand, if n _t +1 is not n _all , the processing of changing the operating unit n _t to n _t +1 is performed. The process proceeds to step ST15.

In step ST14, when n _t = n _all , the calculation unit 12 subtracts 1 from the current operating number n _t and divides the total current I _Lt by the number n (= n _t −1), _Preset digit processing (for example, rounding off, etc.) is performed to calculate a unit load current I _Ltn-1 per rectifier unit (step ST18).
And the calculating part 12 _{reads the} electric power loss P _lossn-1 memorize _| stored corresponding to the calculated unit load current _ILtn-1 from the loss table of the memory _| storage part 14 (step ST19).
Next, the operation unit 12 determines whether or not the power loss P _lossn-1 is larger than the power loss P _lossn (step ST20). If larger, the process proceeds to step ST12, and if smaller, the process is performed. Proceed to step ST21.
When the power loss P _lossn-1 is smaller than the power loss P _lossn , the calculation unit 12 determines whether n _t -1 is 1 (step ST21), and n _t -1 is 1. In this case, since the number of operating units cannot be decreased from n = 1, the process proceeds to step ST12. On the other hand, when n _t −1 is not 1, after performing the process of changing the operating unit n _t to n _t −1. Then, the process proceeds to step ST18.

By the above-described processing, as in the flowcharts of FIGS. 7 and 8, in step ST <b> 12, the calculation unit 12 determines the new number of operating units corresponding to the smallest power loss P corresponding to the operating state of the load. 15 is output.
For example, when the power loss P _lossn is the smallest, the calculation unit 12 _outputs the current operation number n _t as the operation number of the calculation result to the control unit 15, and when the power loss P _{lossn + 1} is the smallest, the current operation number n _t + m units (m is the number of times step ST4 or ST15 has been processed) is output to the control unit 15 as the operation number of operation results, and when the power loss P _lossn−1 is the smallest, the current operation number n _t −m The table (m is the number of times step ST6 or ST18 has been processed) is output to the control unit 15 as the number of operating results.
As a result, the control unit 15 determines the number of operating rectifier units with the smallest power loss corresponding to the operating state of the load, as in the flowcharts of FIGS. As many rectifier units as possible are put into operation, and DC power is supplied to the load.

As described above, in the second embodiment, when the number of rectifier units operating corresponding to the load power is determined so as to minimize the power loss of each rectifier unit, the load facility 200 is operated. It obtains the total current I _Li is the total load current of the rectifier unit in the state, dividing this total current in the current production volume. Then, the power loss P _iosan corresponding to the unit load current I _Lin per unit obtained as a result of the division is read from the loss table. Then, the number of operating rectifier units is increased / decreased, and the power loss _{Piosan of} each of the increased / decreased operating numbers is compared to determine the operating number with the least power loss, and the control unit that _sets the rectifier unit of this operating number to the operating state. I do.
For this reason, in the present embodiment, the DC load power can be supplied with the number of operating rectifier units with the least power loss corresponding to the load current supplied to the load facility 200, and the power loss compared to the conventional case. Can be reduced.

Further, in the configuration of FIG. 1, the semiconductor switch 2-1g2 may not be provided, and only the diode 2-1g1 may be provided.
In the case of this configuration, the control unit 15 performs switching control of the switch 2-1e in the rectifier unit when each rectifier unit is set to an active state or a standby state, and the detected voltage at the connection point Q in the voltage dividing circuit 2-1d. The value is adjusted, and the voltage value output from the DC-DC unit 2-1c is controlled.
That is, when the rectifier unit is set to the standby state, by opening the switch 2-1e, the detected voltage value at the connection point Q is adjusted to be higher than the detected voltage value in the operating state, and the DC-DC unit 2-1c The output voltage value is reduced compared to the operating state, and the supply of load current is stopped by turning off the diode 2-1g1.
With the configuration described above, by adjusting the voltage value at the connection point Q, each rectifier unit can be easily put into an operating state or a standby state.

  Note that a program for realizing the function of the operating number control unit in FIG. 1 (the operations in the flowcharts in FIGS. 7 and 8 and FIGS. 9 and 10) is recorded on a computer-readable recording medium, and this recording is performed. The program recorded on the medium may be read into the computer system and executed to calculate the number of operating units and control the operation of the rectifier unit. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer system” includes a WWW system having a homepage providing environment (or display environment). The “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and a storage device such as a hard disk built in the computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

DESCRIPTION OF SYMBOLS 1 ... DC power supply device 2-1, 2-2, 2-3, 2-n ... Rectifier unit 2-1a ... FIL part 2-1b ... PFC part 2-1c ... DC-DC part 2-1d ... Voltage dividing circuit 2-1e: Switch 2-1f: Conversion control unit 2-1f1: Amplifier circuit 2-1f2: Comparator 2-1f3: Drive circuit 2-1f4: Reference voltage source 2-1f5 ... Triangular wave generation circuit 3 ... Current sensor 4 ... Current measuring unit 5 ... Number of operating units control unit 9 ... Output terminal 11 ... Input unit 12 ... Calculation unit 13 ... Timer 14 ... Storage unit 15 ... Control unit 100 ... Commercial power source 200 ... Load facility

Claims (10)

A plurality of rectifier units connected in parallel with an output terminal for inputting AC power and outputting DC power;
A current sensor that measures the current value of the DC power and outputs the current value of the DC power;
Based on the current value, the number of operating rectifier units that minimizes the loss generated in the process of power conversion from alternating current to direct current of each of the rectifier units is obtained, and direct current power is output from the rectifier units of the operating number. And an operating unit control unit to control,
The rectifier unit compares a detected voltage value obtained by dividing its output voltage by a voltage dividing circuit with a preset reference voltage, and performs control so that the detected voltage becomes equal to the reference voltage, and a diode And a voltage is output via a parallel connection of semiconductor switches, and the operation number control unit performs operation control of the rectification unit corresponding to the operation number by controlling the voltage dividing ratio of the voltage dividing circuit. DC power supply device.   The operating number control unit controls the voltage dividing ratio of the voltage dividing circuit, increases the detection voltage value compared to before voltage division, and decreases the voltage value of the output voltage compared to the voltage before the control. The DC power supply device according to claim 1, wherein the operation of the rectifier unit is stopped by the operation.   The operating number control unit performs control to turn on the semiconductor switch provided in the rectifier unit to be supplied with power and to turn off the semiconductor switch provided in the rectifier unit to stop power supply. The DC power supply device according to claim 1, wherein power loss generated in the diode unit is reduced. The voltage dividing circuit is configured by connecting resistors in series, and a switch is connected in parallel with any of the resistors,
The DC power supply device according to any one of claims 1 to 3, wherein the operating number control unit controls the voltage dividing ratio of the voltage dividing circuit by controlling the switching of the switch.   The voltage dividing ratio of the detected voltage value is set in advance so that any of the voltages controlled by the operating number control unit falls within a voltage range in which the load can operate (input voltage range of the load). The DC power supply device according to any one of claims 1 to 4. The operating number control unit is
An operating number table in which the current value of the DC power and the operating number of rectifier units that minimize the conversion loss at the current value are set correspondingly,
The number of operating units of the rectifier unit corresponding to the current value from the current sensor is read from the operating unit table, and a calculating unit for obtaining the number of operating rectifier units;
6. The DC power supply device according to claim 1, further comprising: a control unit that controls the switch according to the number of operating units obtained by the calculation unit. The operating number control unit is
A loss table that associates the current value output per rectifier unit with the power loss in the case of the current value;
The current value from the current sensor is divided by the number of currently operating rectifier units to obtain a first current value of the output current per unit, and the power corresponding to the first current value The loss is read from the loss table, and the current value from the current sensor is divided by the number of current operating units that are increased or decreased by one to obtain the second and third current values, respectively. When the power loss corresponding to each of the third current values is read from the loss table and the power loss at the first current value is smaller than the power loss at the second and third current values, the current operating number is calculated as the result. When the power loss in the reduced number of units is small, the number of units with the smallest power loss is subtracted. On the other hand, if the power loss in the increased number is small, the smallest A calculation unit increases to the number to be had power loss, and outputs the number of smallest obtain a power loss as number of operating the rectifier unit,
6. The DC power supply device according to claim 1, further comprising: a control unit that controls the switch according to the number of operating units obtained by the calculation unit.   2. The semiconductor switch according to claim 1, wherein the semiconductor switch is one of a MOS-FET, a junction transistor, an electrostatic induction transistor, or an insulated gate bipolar transistor, and the diode is a parasitic diode of the transistor. The DC power supply device according to any one of 7.   The semiconductor switch is one of a MOS-FET, a junction transistor, a static induction transistor, or an insulated gate bipolar transistor, and the diode is connected to the transistor in parallel with the output direction of DC power as the forward direction. The DC power supply device according to any one of claims 1 to 7, wherein the DC power supply device is provided. Each of the plurality of rectifier units connected in parallel converts AC power into DC power, and outputs the DC power to the same output terminal.
A process in which a current sensor measures the current value of the DC power and outputs the current value of the DC power;
The operating unit control unit obtains the operating number of the rectifier unit that minimizes the loss generated in the process of power conversion from AC to DC of each of the rectifier units according to the current value. A process of controlling power to be output;
The rectifier unit compares a detected voltage value obtained by dividing the output voltage of the rectifier unit by a voltage dividing circuit with a preset reference voltage, and performs control so that the detected voltage becomes equal to the reference voltage. A process of outputting a voltage through parallel connection of semiconductor switches;
The method for controlling a DC power supply apparatus, comprising: a step of controlling the operation of the rectification unit corresponding to the number of operating units by controlling the voltage dividing ratio of the voltage dividing circuit.

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